Publications by authors named "Carlo Cavallotti"

89 Publications

Crossed-Beam and Theoretical Studies of the O(P, D) + Benzene Reactions: Primary Products, Branching Fractions, and Role of Intersystem Crossing.

J Phys Chem A 2021 Sep 17;125(38):8434-8453. Epub 2021 Sep 17.

Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, 20131 Milano, Italy.

Reliable modeling of hydrocarbon oxidation relies critically on knowledge of the branching fractions (BFs) as a function of temperature () and pressure () for the products of the reaction of the hydrocarbon with atomic oxygen in its ground state, O(P). During the past decade, we have performed in-depth investigations of the reactions of O(P) with a variety of small unsaturated hydrocarbons using the crossed molecular beam (CMB) technique with mass spectrometric (MS) detection and time-of-flight (TOF) analysis, combined with synergistic theoretical calculations of the relevant potential energy surfaces (PESs) and statistical computations of product BFs, including intersystem crossing (ISC). This has allowed us to determine the primary products, their BFs, and extent of ISC to ultimately provide theoretical channel-specific rate constants as a function of and . In this work, we have extended this approach to the oxidation of one of the most important species involved in the combustion of aromatics: the benzene (CH) molecule. Despite extensive experimental and theoretical studies on the kinetics and dynamics of the O(P) + CH reaction, the relative importance of the CHO (phenoxy) + H open-shell products and of the spin-forbidden CH (cyclopentadiene) + CO and phenol adduct closed-shell products are still open issues, which have hampered the development of reliable benzene combustion models. With the CMB technique, we have investigated the reaction dynamics of O(P) + benzene at a collision energy () of 8.2 kcal/mol, focusing on the occurrence of the phenoxy + H and spin-forbidden CH + CO and phenol channels in order to shed further light on the dynamics of this complex and important reaction, including the role of ISC. Concurrently, we have also investigated the reaction dynamics of O(D) + benzene at the same . Synergistic high-level electronic structure calculations of the underlying triplet/singlet PESs, including nonadiabatic couplings, have been performed to complement and assist the interpretation of the experimental results. Statistical (RRKM)/master equation (ME) computations of the product distribution and BFs on these PESs, with inclusion of ISC, have been performed and compared to experiment. In light of the reasonable agreement between the CMB experiment, literature kinetic experimental results, and theoretical predictions for the O(P) + benzene reaction, the so-validated computational methodology has been used to predict (i) the BF between the CHO + H and CH + CO channels as a function of collision energy and temperature (at 0.1 and 1 bar), showing that their increase progressively favors radical (phenoxy + H)-forming over molecule (CH + CO and phenol stabilization)-forming channels, and (ii) channel-specific rate constants as a function of and , which are expected to be useful for improved combustion models.
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http://dx.doi.org/10.1021/acs.jpca.1c06913DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8488941PMC
September 2021

Theoretical Study of the Extent of Intersystem Crossing in the O(P) + CH Reaction with Experimental Validation.

J Phys Chem Lett 2020 Nov 30;11(22):9621-9628. Epub 2020 Oct 30.

Laboratory of Molecular Processes in Combustion, Department of Chemistry, Biology and Biotechnologies, University of Perugia, 06123 Perugia, Italy.

The extent of intersystem crossing in the O(P) + CH reaction, a prototypical system for spin-forbidden reactions in oxygenated aromatic molecules, is theoretically evaluated for the first time. Calculations are performed using nonadiabatic transition-state theory coupled with stochastic master equation simulations and Landau-Zener theory. It is found that the dominant intersystem crossing pathways connect the T2 and S0 potential energy surfaces through at least two distinct minimum-energy crossing points. The calculated channel-specific rate constants and intersystem crossing branching fractions differ from previous literature estimates and provide valuable kinetic data for the investigation of benzene and polycyclic aromatic hydrocarbons oxidation in interstellar, atmospheric, and combustion conditions. The theoretical results are supported by crossed molecular beam experiments with electron ionization mass-spectrometric detection and time-of-flight analysis at 8.2 kcal/mol collision energy. This system is a suitable benchmark for theoretical and experimental studies of intersystem crossing in aromatic species.
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http://dx.doi.org/10.1021/acs.jpclett.0c02866DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8016199PMC
November 2020

Electronic structure-based rate rules for addition-elimination reactions on mono-aromatic hydrocarbons with single and double OH/CH/OCH/CHO/CH substituents: a systematic theoretical investigation.

Phys Chem Chem Phys 2020 Sep;22(36):20368-20387

CRECK Modelling Lab, Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133 Milano, Italy.

The recent interest in bio-oils combustion and the key role of mono-aromatic hydrocarbons (MAHs) in existing kinetic frameworks, both in terms of poly-aromatic hydrocarbons growth and surrogate fuels formulation, motivates the current systematic theoretical investigation of one of the relevant reaction classes in MAHs pyrolysis and oxidation: ipso substitution by hydrogen. State-of-the-art theoretical methods and protocols implemented in automatized computational routines allowed to investigate 14 different potential energy surfaces involving MAHs with hydroxy and methyl single (phenol and toluene) and double (o-,m-,p-C6H4(OH)2, o-,m-,p-CH3C6H4OH, and o-,m-,p-C6H4(CH3)2) substituents, providing rate constants for direct implementation in existing kinetic models. The accuracy of the adopted theoretical method was validated by comparison of the computed rate constants with the available literature data. Systematic trends in energy barriers, pre-exponential factors, and temperature dependence of the Arrhenius parameters were found, encouraging the formulation of rate rules for ipso substitutions on MAHs. The rules here proposed allow to extrapolate from a reference system the necessary activation energy and pre-exponential factor corrections for a large number of reactions from a limited set of electronic structure calculations. We were able to estimate rate constants for other 63 ipso addition-elimination reactions on di-substituted MAHs, reporting in total 75 rate constants for ipso substitution reactions o-,m-,p-R'C6H4R + → C6H5R + ', with R,R' = OH/CH3/OCH3/CHO/C2H5, in the 300-2000 K range. Additional calculations performed for validation showed that the proposed rate rules are in excellent agreement with the rate constants calculated using the full computational protocol in the 500-2000 K range, generally with errors below 20%, increasing up to 40% in a few cases. The main results of this work are the successful application of automatized electronic structure calculations for the derivation of accurate rate constants for ipso substitution reactions on MAHs, and an efficient and innovative approach for rate rules formulation for this reaction class.
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http://dx.doi.org/10.1039/d0cp03099fDOI Listing
September 2020

State-of-the-Art Quantum Chemistry Meets Variable Reaction Coordinate Transition State Theory to Solve the Puzzling Case of the HS + Cl System.

J Chem Theory Comput 2020 Aug 15;16(8):5090-5104. Epub 2020 Jul 15.

Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.

The atmospheric reaction of HS with Cl has been reinvestigated to check if, as previously suggested, only explicit dynamical computations can lead to an accurate evaluation of the reaction rate because of strong recrossing effects and the breakdown of the variational extension of transition state theory. For this reason, the corresponding potential energy surface has been thoroughly investigated, thus leading to an accurate characterization of all stationary points, whose energetics has been computed at the state of the art. To this end, coupled-cluster theory including up to quadruple excitations has been employed, together with the extrapolation to the complete basis set limit and also incorporating core-valence correlation, spin-orbit, and scalar relativistic effects as well as diagonal Born-Oppenheimer corrections. This highly accurate composite scheme has also been paralleled by less expensive yet promising computational approaches. Moving to kinetics, variational transition state theory and its variable reaction coordinate extension for barrierless steps have been exploited, thus obtaining a reaction rate constant (8.16 × 10 cm molecule s at 300 K and 1 atm) in remarkable agreement with the experimental counterpart. Therefore, contrary to previous claims, there is no need to invoke any failure of the transition state theory, provided that sufficiently accurate quantum-chemical computations are performed. The investigation of the puzzling case of the HS + Cl system allowed us to present a robust approach for disclosing the thermochemistry and kinetics of reactions of atmospheric and astrophysical interest.
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http://dx.doi.org/10.1021/acs.jctc.0c00354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8009477PMC
August 2020

Combined Experimental and Theoretical Studies of the O(P) + 1-Butene Reaction Dynamics: Primary Products, Branching Fractions, and Role of Intersystem Crossing.

J Phys Chem A 2019 Nov 8;123(46):9934-9956. Epub 2019 Nov 8.

Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta" , Politecnico di Milano , 20131 Milano , Italy.

Information on the detailed mechanism and dynamics (primary products, branching fractions (BFs), and channel specific rate constants as a function of temperature) for many important combustion reactions of O(P) with unsaturated hydrocarbons is still lacking. We report synergistic experimental/theoretical studies on the mechanism and dynamics of the O(P) + 1-CH (1-butene) reaction by combining crossed molecular beam (CMB) experiments with soft electron ionization mass-spectrometric detection and time-of-flight analysis at 10.5 kcal/mol collision energy () to high-level electronic structure calculations of the underlying triplet and singlet potential energy surfaces (PESs) and statistical Rice-Ramsperger-Kassel-Marcus/Master Equation (RRKM/ME) computations of BFs including intersystem crossing (ISC). The reactive interaction of O(P) with 1-butene is found to mainly break apart the 4-carbon atom chain, leading to the radical product channels ethyl + vinoxy (BF = 0.34 ± 0.11), methyl + CHO (BF = 0.28 ± 0.09), formyl + propyl (BF = 0.17 ± 0.05), ethyl + acetyl (BF = 0.014 ± 0.007), and butanal radical (ethylvinoxy) + H (BF = 0.013 ± 0.004), and molecular product channels formaldehyde + propenylidene/propene (BF = 0.15 ± 0.05) and butenone (ethyl ketene) + H (BF = 0.037 ± 0.015). As some of these products can only be formed via ISC from triplet to singlet PESs, from BFs an extent of ISC of 50% is inferred. This value is significantly larger than that recently observed for O(P) + propene (22%) at similar , underlying the question of how important it is to consider nonadiabatic effects for these and similar combustion reactions. Comparison of the derived BFs with those of statistical (RRKM/ME) simulations on the coupled triplet/singlet PESs shows good agreement, warranting the use of the RRKM/ME approach to provide information on the variation of BFs with temperature and to derive channel specific rate constants as a function of temperature () and pressure (). Notably, ISC is predicted to decrease strongly with increasing temperature (from about 70% at 300 K to 46% at = 10.5 kcal/mol, and about 1% at 2000 K). The present results lead to a detailed understanding of the complex reaction mechanism of O(P) + 1-butene and, by providing channel specific rate constants as a function of and , should facilitate the improvement of current fossil-fuel (1-butene) as well as biofuel (1-butanol) combustion models.
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http://dx.doi.org/10.1021/acs.jpca.9b07621DOI Listing
November 2019

Molecular Modeling of the Interaction of Protein L with Antibodies.

ACS Omega 2017 Oct 6;2(10):6464-6472. Epub 2017 Oct 6.

Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy.

Protein L (PpL) is a bacterial protein which is used in the affinity chromatography stage of the production of monoclonal antibodies because of its ability to form high affinity complexes with the light chains of immunoglobulins. In the present work, the binding interfaces between one domain of PpL and antigen-binding fragments (Fab) have been investigated adopting molecular dynamics with the aim of determining the binding contribution of the residues located at the Fab-PpL interface. Because it is known that PpL binds antibodies through two distinct binding sites with different affinities, simulations were performed for both sites to determine interaction free energies to assess the relative binding contribution of the two sites. Mutational studies were then performed only on the dominant binding site. The binding free energy was evaluated with the molecular mechanics Poisson-Boltzmann surface area (MMPBSA) and umbrella sampling/weighted histogram analysis methods. Key residues for the formation of the dominant binding site complex were identified by means of alanine scanning performed both for the Fab and PpL domains. Residues of the light chain of the antibody that contribute most to binding were found to be located between SER7 and VAL13. Four residues from PpL are important for the stability of the complex: PHE839, LYS840, GLU849, and TYR853. Three residues of PpL that do not contribute to the interaction were mutated to histidine (HIS), which changes its protonation state as a function of pH, to find whether this could allow us to control the binding interaction energy. This can be useful in the elution stage of the affinity chromatography purification of antibodies if PpL is used as a ligand. These residues are GLN835, THR836, and ALA837. Molecular dynamics simulations with both protonated and unprotonated HIS were performed to mimic how changing pH may reflect on protein-ligand interaction energies. The MMPBSA approach was used to evaluate the variation of the affinity of the mutated systems with reference to the wild type. Our results show that these mutations could help in disrupting the complex under acidic conditions without impairing the affinity of PpL for the light chains at higher pHs.
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http://dx.doi.org/10.1021/acsomega.7b01123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6645367PMC
October 2017

Molecular insight into protein binding orientations and interaction modes on hydrophobic charge-induction resin.

J Chromatogr A 2017 Aug 30;1512:34-42. Epub 2017 Jun 30.

Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address:

Hydrophobic charge-induction chromatography (HCIC) with 4-mercaptoethyl-pyridine (MEP) as the functional ligand has been developed as a new technology for antibody purification. In the present work, molecular simulation methods were developed to investigate the interactions between the Fc fragment of IgG and a MEP ligand net. The MM/PBSA method was used to evaluate the binding energy for the MEP ligand net at different densities. It was found that ligand density had significant influence on the binding of Fc. Potential binding conformations were further analyzed by molecular dynamics simulation. It was found that the interaction between Fc and MEP ligand net is driven by self-adaptive conformation adjustment and multiple-site binding. Hydrophobic forces dominate the binding interaction, which appeared as the results of synergistic actions of binding sites located on CH2, CH3, and the consensus binding site (CBS) of the Fc fragment. At acidic pH, the electrostatic repulsion between the basic residues and the protonated pyridine ring group on MEP ligands is the main driving force for the detachment of the Fc fragment from the MEP net.
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http://dx.doi.org/10.1016/j.chroma.2017.06.071DOI Listing
August 2017

Exploring short intramolecular interactions in alkylaromatic substrates.

Phys Chem Chem Phys 2016 Oct;18(42):29616-29628

Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta", Politecnico di Milano, via Mancinelli 7, I-20131 Milano, Italy.

From proteins and peptides to semiconducting polymers, aliphatic chains on aromatic groups are recurring motifs in macromolecules from very diverse application fields. Fields in which molecular folding and packing determine the macroscopic physical properties that make such advanced materials appealing in the first place. Within each macromolecule, the intrinsic structure of each unit defines how it interacts with its neighbours, ultimately opening up or denying certain backbone conformations. This eventually also determines how macromolecules interact with each other. This account deals specifically with the conformational problem of many common alkylaromatic units, examining the features of an intramolecular interaction involving a side chain with as few as three methylene groups. A set of 23 model compounds featuring an intramolecular interaction between an aliphatic X-H (X = C, N, O, and S) bond and an aromatic ring was considered. Quantitative computational analysis was made possible, thanks to complete basis set extrapolated CCSD(T) calculations and NCI topological analysis, the latter of which revealed an elaborate network of dispersive and steric interactions leading to somewhat unintuitive and unexpected results, such as the higher energetic stability of certain twisted conformational isomers over those with extended side chains. Vicinal covalent effects from polarizing groups and various heteroatoms, along with the occurrence of non-dispersive phenomena, were also investigated. The conclusions drawn from the investigation include a comprehensive set of guidelines intended to aid in the prediction of the most stable conformation for this class of building blocks. Our findings affect a variety of different research fields, including the tailoring of functional materials for organic electronics and photovoltaics, with insights into a rational treatment of conformational disorder, and the study of protein- and peptide-folding preferences, putting an emphasis on peculiar interactions between the backbone and aromatic residues.
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http://dx.doi.org/10.1039/c6cp03323gDOI Listing
October 2016

A Qualitative and Quantitative Study of the Innervation of the Human Non Pregnant Uterus.

Curr Protein Pept Sci 2017 ;18(2):140-148

Division of Medical Genetics, Department of Biomedical Sciences and Human Oncology, Universita di Bari "Aldo Moro", 70124 Bari, Italy.

Human female reproductive system is closely dependent by hormonal stimulation. Anyway it is now commonly stated that autonomic innervation system regulates, along with hormonal stimulation, the uterine physiology. Cholinergic and adrenergic innervations have a critical role in mediating input to the uterus, but other neurotransmitters and neuropeptides exist that influence uterine physiology, as well. In the present investigation, we analyzed the uterine distribution of a large set of neurotransmitters, focusing on adrenergic, noradredenergic, acetylcholine (AChE) positive, dopaminergic, serotoninergic and peptidergic neurofibers; among these latter, we focused on those releasing prolattine, enkephalines (ENKs), Vasoactive Intestinal Polypeptide (VIP), substance P (SP) and oxytocine. Authors demonstrate the differential localization of these neurofibers in non pregnant uterine fundus, corpus and cervix, sampling myometrial assays of 31 patients submitted to hysterectomy. In fundus uteri, we observed a prevalence of prolactinergic (32.1 ± 1.4 Conventional Unit, C.U.) and adrenergic (36.4 ± 4.5 C.U.) neurofibers; in uterine body VIP positive neurofibers (32.6 ± 4.8 C.U.) and prolactinergic neurofibers (30.3 ± 1.2 C.U.) were the most represented. In uterine cervix, we detected the highest concentration of all the neurofibers analysed, with enkephalinergic neurofibers (94 ± 1.7 C.U.), oxitocinergic neurofibers (72.1 ± 5.1 C.U.), SP positive neurofibers (66.1 ± 4.4 C.U.), acetylcholine positive neurofibers (64.5± 3.6 C.U.), serotoninergic neurofibers (56.4 ± 3.9 C.U.) and VIP positive neurofibers (58.3 ± 5.2 C.U.) being the most expressed. This study demonstrates that uterine cervix harbors a higher concentration of almost all neurotransmitters, compared to the other two uterine anatomic sites. The uterine cervix is largely involved during pregnancy and labor, and the rich neurotransmitters density could contribute to confer to the cervix a proper potential plasticity, necessary for pregnancy and labour.
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http://dx.doi.org/10.2174/1389203717666160330105341DOI Listing
October 2017

Reaction Dynamics of O((3)P) + Propyne: I. Primary Products, Branching Ratios, and Role of Intersystem Crossing from Crossed Molecular Beam Experiments.

J Phys Chem A 2016 Jul 12;120(27):4603-18. Epub 2016 Apr 12.

Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano , 20131 Milano, Italy.

We performed synergic experimental/theoretical studies on the mechanism of the O((3)P) + propyne reaction by combining crossed molecular beams experiments with mass-spectrometric detection and time-of-flight analysis at 9.2 kcal/mol collision energy (Ec) with ab initio electronic structure calculations at a high level of theory of the relevant triplet and singlet potential energy surfaces (PESs) and statistical calculations of branching ratios (BRs) taking into account intersystem crossing (ISC). In this paper (I) we report the results of the experimental investigation, while the accompanying paper (II) shows results of the theoretical investigation with comparison to experimental results. By exploiting soft electron ionization detection to suppress/mitigate the effects of the dissociative ionization of reactants, products, and background gases, product angular and velocity distributions at different charge-to-mass ratios were measured. From the laboratory data angular and translational energy distributions in the center-of-mass system were obtained for the five competing most important product channels, and product BRs were derived. The reactive interaction of O((3)P) with propyne under single collision conditions is mainly leading to the rupture of the three-carbon atom chain, with production of the radical products methylketenyl + atomic hydrogen (BR = 0.04), methyl + ketenyl (BR = 0.10), and vinyl + formyl (BR = 0.11) and the molecular products ethylidene/ethylene + carbon monoxide (BR = 0.74) and propandienal + molecular hydrogen (BR = 0.01). Because some of the products can only be formed via ISC from the entrance triplet to the low-lying singlet PES, we infer from their BRs an amount of ISC larger than 80%. This value is dramatically large when compared to the negligible ISC reported for the O((3)P) reaction with the simplest alkyne, acetylene. At the same time, it is much larger than that (∼20%) recently observed in the related reaction of the three-carbon atom alkene, O((3)P) + propene at a comparable Ec. This poses the question of how important it is to consider nonadiabatic effects and their dependence on molecular structure for this kind of combustion reactions. The prevalence of the CH3 over the H displacement channels is not explained by invoking a preference for the addition on the methyl-substituted acetylenic carbon atom, but rather it is believed to be due to the different tendencies of the two addition triplet intermediates CH3CCHO (preferentially leading to H elimination) and CH3COCH (preferentially leading to CH3 elimination) to undergo ISC to the underlying singlet PES. It is concluded that the main coproduct of the CO forming channel is singlet ethylidene ((1)CH3CH) rather than ground-state ethylene. By comparing the derived BRs with those very recently derived from kinetics studies at room temperature and 4 Torr we obtained information on how BRs vary with collision energy. The extent of ISC is estimated to remain essentially constant (∼85%) with increasing Ec from ∼1 to ∼10 kcal/mol. The present experimental results shed light on the mechanism of the title reaction at energies comparable to those involved in combustion and, when compared with the results from the statistical calculations on the ab initio coupled PESs (see accompanying paper II), lead to an in-depth understanding of the rather complex reaction mechanism of O + propyne. The overall results are expected to contribute to the development of more refined models of hydrocarbon combustion.
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http://dx.doi.org/10.1021/acs.jpca.6b01563DOI Listing
July 2016

Reaction Dynamics of O((3)P) + Propyne: II. Primary Products, Branching Ratios, and Role of Intersystem Crossing from Ab Initio Coupled Triplet/Singlet Potential Energy Surfaces and Statistical Calculations.

J Phys Chem A 2016 Jul 13;120(27):4619-33. Epub 2016 Apr 13.

Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia , 06123 Perugia, Italy.

The mechanism of the O((3)P) + CH3CCH reaction was investigated using a combined experimental/theoretical approach. Experimentally the reaction dynamics was studied using crossed molecular beams (CMB) with mass-spectrometric detection and time-of-flight analysis at 9.2 kcal/mol collision energy. Theoretically master equation (ME) simulations were performed on a potential energy surface (PES) determined using high-level ab initio electronic structure calculations. In this paper (II) the theoretical results are described and compared with experiments, while in paper (I) are reported and discussed the results of the experimental study. The PES was investigated by determining structures and vibrational frequencies of wells and transition states at the CASPT2/aug-cc-pVTZ level using a minimal active space. Energies were then determined at the CASPT2 level increasing systematically the active space and at the CCSD(T) level extrapolating to the complete basis set limit. Two separate portions of the triplet PES were investigated, as O((3)P) can add either on the terminal or the central carbon of the unsaturated propyne bond. Minimum energy crossing points (MECPs) between the triplet and singlet PESs were searched at the CASPT2 level. The calculated spin-orbit coupling constants between the T1 and S0 electronic surfaces were ∼25 cm(-1) for both PESs. The portions of the singlet PES that can be accessed from the MECPs were investigated at the same level of theory. The system reactivity was predicted integrating stochastically the one-dimensional ME using Rice-Ramsperger-Kassel-Marcus theory to determine rate constants on the full T1/S0 PESs, accounting explicitly for intersystem crossing (ISC) using the Landau-Zener model. The computational results are compared both with the branching ratios (BRs) determined experimentally in the companion paper (I) and with those estimated in a recent kinetic study at 298 K. The ME results allow to interpret the main system reactivity: CH3CCO + H and CH3 + HCCO are the major channels active on the triplet PES and are formed from the wells accessed after O addition to the terminal and central C, respectively; (1)CH3CH + CO and C2H3 + HCO are the major channels active on the singlet PES and are formed from the methylketene and acrolein wells after ISC. However, also a large number of minor channels (∼15) are active, so that the system reactivity is quite complicated. The comparison between computational and experimental BRs is quite good for the kinetic study, while some discrepancy with the CMB estimations suggests that dynamic non-ergodic effects may influence the system reactivity. Channel specific rate constants are calculated in the 300-2250 K and 1-30 bar temperature and pressure ranges. It is found that as the temperature increases the H abstraction reaction, whose contribution is negligible in the experimental conditions, increases in relevance, and the extent of ISC decreases from ∼80% at 300 K to less than 2% at 2250 K.
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http://dx.doi.org/10.1021/acs.jpca.6b01564DOI Listing
July 2016

Neurotransmitters and Neuropeptides Expression in the Uterine Scar After Cesarean Section.

Curr Protein Pept Sci 2017 ;18(2):175-180

Department of Gynecology and Obstetrics, Santa Maria Hospital, Bari, Italy.

Peptides and neuropeptides influence the uterine disorders of healing or cicatrization, chronic pelvic pain and disorder of pregnancy, labor and puerperium. They also promote changes in the lower uterine segment (LUS) during pregnancy, labor and delivery. We investigated the tissue quantity of neurotensin (NT), neuropeptide tyrosin (NPY) and Protein Gene Product 9.5 (PGP 9.5) in women submitted to elective cesarean section (CS) and urgent CS. During surgery, authors biopsied tissue samples of vesico-uterine space (VUS) to detect nerve fibers, and compared them. VUS samples from 106 patients have been evaluated with light microscopy, immunochemistry and Immunohistochemistry, and finally by Quantimet Leica analyzer software. Significantly higher amount of nerve fibers, containing NT, NPY and PGP 9.5 have been found in VUS tissue samples obtained during the first elective CS and during the first urgent CS were respectively 5±0.7, 7±0.6 and 5±0.9 CU and 2.5±0.5, 3.6±0.4 and 3.5±0.9 CU (p<0.05). This neurotransmitter reduction should indicate the inflammatory damage of cervical tissue for LUS over distension in dystocic-prolonged labor before CS. These results may be correlated with the decrease of NT, NPY and PGP 9.5, responsible for an optimal healing and LUS functions. In our opinion, the presence of neuropeptides reduction in uterine samples of women undergoing urgent CS may be due to a prolonged fetal head station in LUS, with a tissue denervation, in consequence of both overdistension and inflammatory process of the dystocic LUS.
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http://dx.doi.org/10.2174/1389203717666160322150034DOI Listing
October 2017

Laminin and Collagen IV: Two Polypeptides as Marker of Dystocic Labor.

Curr Protein Pept Sci 2017 ;18(2):149-154

Department of Gynecology and Obstetrics, Santa Maria Hospital, Bari, Italy.

Collagen IV and Laminin are localized in cells and tissue of numerous human organs including the uterus, where these polypeptides control either age changes, or uterus growth in pregnancy, or ripening and dilatation in labor. Authors examined the polypeptides distribution of collagen IV and Laminin in the human pregnant uterus, in normal and dystocic labor, to clarify their physiologic role, by distribution and/or their changes in prolonged dystocic labor. We collected lower uterine segment (LUS) fragments during cesarean section (CS); these biopsies were treated with basic morphological staining for the observation of microscopic- anatomic details. Other samples were processed with immunohistochemical staining for collagen IV and for membrane bound Laminin. All morphological and immunochemical results were analyzed with quantitative analysis of images and statistical analysis of data. Both Collagen IV and Laminin show changes in the pregnant uterus before 4 hours of full cervical dilatation in patients after 4 hours. All the three types of the human uterine cells, mucosal, submucosal and smooth muscular cells, are more reduced in LUS after 4 hours of cervical dilatation in dystocic labor. The connective tissues (including fibroblast) show the most evident changes in the dystocic LUS, collagen IV and laminin changes during cervical dilatation in prolonged dystocic labor, with a decreased elasticity with increased roughness and dryness. The LUS anatomical modifications during labor can be the cause of pathological changes in protracted dystocic labor. In the dystocic labor that lasts more than 4 hours from the complete cervical ripening and dilatation, the laminin and collagen IV concentration reduces in the LUS tissue. In dystocic labor, delivery should be completed before the 3 hours of full dilation, to avoid a reduction of laminin and collagen IV and a worsening of LUS healing for the next pregnancy.
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http://dx.doi.org/10.2174/1389203717666160322150125DOI Listing
October 2017

Isomer-Specific Chemistry in the Propyne and Allene Reactions with Oxygen Atoms: CH3CH + CO versus CH2CH2 + CO Products.

J Phys Chem Lett 2016 Mar 4;7(6):1010-5. Epub 2016 Mar 4.

Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano , 20131 Milano, Italy.

We report direct experimental and theoretical evidence that, under single-collision conditions, the dominant product channels of the O((3)P) + propyne and O((3)P) + allene isomeric reactions lead in both cases to CO formation, but the coproducts are singlet ethylidene ((1)CH3CH) and singlet ethylene (CH2CH2), respectively. These data, which settle a long-standing issue on whether ethylidene is actually formed in the O((3)P) + propyne reaction, suggest that formation of CO + alkylidene biradicals may be a common mechanism in O((3)P) + alkyne reactions, in contrast to formation of CO + alkene molecular products in the corresponding isomeric O((3)P) + diene reactions, either in combustion or other gaseous environments. These findings are of fundamental relevance and may have implications for improved combustion models. Moreover, we predict that the so far neglected (1)CH3CH + CO channel is among the main reaction routes also when the C3H4O singlet potential energy surface is accessed from the OH + C3H3 (propargyl) entrance channel, which are radical species playing a key role in many combustion systems.
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http://dx.doi.org/10.1021/acs.jpclett.6b00262DOI Listing
March 2016

Human Lymphatic Mesenteric Vessels: Morphology and Possible Function of Aminergic and NPY-ergic Nerve Fibers.

Lymphat Res Biol 2015 Sep 25;13(3):170-5. Epub 2015 Aug 25.

2 Department of Sensory Organs, Sapienza University of Rome , Rome, Italy .

Background: The lymphatic vessels have been studied in different organs from a morphological to a clinical point of view. Nevertheless, the knowledge of the catecholaminergic control of the lymphatic circulation is still incomplete. The aim of this work is to study the presence and distribution of the catecholaminergic and NPY-ergic nerve fibers in the whole wall of the human mesenteric lymphatic vessels in order to obtain knowledge about their morphology and functional significance.

Materials And Methods: The following experimental procedures were performed: 1) drawing of tissue containing lymphatic vessels; 2) cutting of tissue; 3) staining of tissue; 4) staining of nerve fibers; 5) histofluorescence microscopy for the staining of catecholaminergic nerve fibers; 6) staining of neuropeptide Y like-immune reactivity; 7) biochemical assay of proteins; 8) measurement of noradrenaline; 9) quantitative analysis of images; 10) statistical analysis of data.

Results: Numerous nerve fibers run in the wall of lymphatic vessels. Many of them are catecholaminergic in nature. Some nerve fibers are NPY-positive. The biochemical results on noradrenaline amounts are in agreement with morphological results on catecholaminergic nerve fibers. Moreover, the morphometric results, obtained by the quantitative analysis of images and the subsequent statistical analysis of data, confirm all our morphological and biochemical data.

Conclusions: The knowledge of the physiological or pathological mechanism regulating the functions of the lymphatic system is incomplete. Nevertheless the catecholaminergic nerve fibers of the human mesenteric lymphatic vessels come from the adrenergic periarterial plexuses of the mesenterial arterial bed. NPY-ergic nerve fibers may modulate the microcirculatory mesenterial bed in different pathological conditions.
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http://dx.doi.org/10.1089/lrb.2015.0018DOI Listing
September 2015

Relevance of the Channel Leading to Formaldehyde + Triplet Ethylidene in the O((3)P) + Propene Reaction under Combustion Conditions.

J Phys Chem Lett 2014 Dec 21;5(23):4213-8. Epub 2014 Nov 21.

Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, 20131 Milano, Italy.

Comprehension of the detailed mechanism of O((3)P) + unsaturated hydrocarbon reactions is complicated by the existence of many possible channels and intersystem crossing (ISC) between triplet and singlet potential energy surfaces (PESs). We report synergic experimental/theoretical studies of the O((3)P) + propene reaction by combining crossed molecular beams experiments using mass spectrometric detection at 9.3 kcal/mol collision energy (Ec) with high-level ab initio electronic structure calculations of the triplet PES and RRKM/master equation computations of branching ratios (BRs) including ISC. At high Ec's and temperatures higher than 1000 K, main products are found to be formaldehyde (H2CO) and triplet ethylidene ((3)CH3CH) formed in a reaction channel that has never been identified or considered significant in previous kinetics studies at 300 K and that, as such, is not included in combustion kinetics models. Global and channel-specific rate constants were computed and are reported as a function of temperature and pressure. This study shows that BRs of multichannel reactions useful for combustion modeling cannot be extrapolated from room-temperature kinetics studies.
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http://dx.doi.org/10.1021/jz502236yDOI Listing
December 2014

A two level hierarchical model of protein retention in ion exchange chromatography.

J Chromatogr A 2015 Sep 29;1411:50-62. Epub 2015 Jul 29.

Department Chimica, Materiali e Ingegneria Chimica, via Mancinelli 7 20131 Milano, Italy. Electronic address:

Predicting protein retention in ion exchange chromatography (IEX) from first principles is a fascinating perspective. In this work a two level hierarchical modeling strategy is proposed in order to calculate protein retention factors. Model predictions are tested against experimental data measured for Lysozyme and Chymotrypsinogen A in IEX columns as a function of ionic strength and pH. At the highest level of accuracy Molecular Dynamics (MD) simulations in explicit water are used to determine the interaction free energy between each of the two proteins and the IEX stationary phase for a reference pH and ionic strength. At a lower level of accuracy a linear response model based on an implicit treatment of solvation and adopting a static protein structure is used to calculate interaction free energies for the full range of pHs and ionic strengths considered. A scaling coefficient, determined comparing MD and implicit solvent simulations, is then introduced in order to correct the linear response model for errors induced by the adoption of a static protein structure. The calculated free energies are then used to compute protein retention factors, which can be directly compared with experimental data. The possibility to introduce a third level of accuracy is explored testing the predictions of a semiempirical model. A quantitative agreement between the predicted and measured protein retention factors is obtained using the coupled MD-linear response models, supporting the reliability of the proposed approach. The model allows quantifying the electrostatic, van der Waals, and conformational contributions to the interaction free energies. A good agreement between experiments and model is obtained also using the semiempirical model that, although requiring parameterization over higher level models or experimental data, proves to be useful in order to rapidly determine protein retention factors across wide pH and ionic strength ranges as it is computationally inexpensive.
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http://dx.doi.org/10.1016/j.chroma.2015.07.101DOI Listing
September 2015

Analysis of the Gas Phase Kinetics Active during GaN Deposition from NH3 and Ga(CH3)3.

J Phys Chem A 2015 Jul 11;119(28):7858-71. Epub 2015 May 11.

†Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, via Mancinelli 7, 20131 Milano, Italy.

The results of a systematic investigation aimed at determining the dominant gas phase chemistry active during GaN MOVPE are reported and discussed in this work. This study was performed developing a thermodynamic database including the most stable GaN gas phase species and a gas phase mechanism that could efficiently describe their interconversion kinetics. The thermodynamic data and the kinetic mechanism were calculated combining density functional theory and ab initio simulations. Structures and vibrational frequencies of reactants and transition states were determined at the M062X/6-311+G(d,p) level, while energies were computed at the ROCBS-QB3 level. Rate constants were calculated using transition state theory using the rigid rotor - harmonic oscillator approximation and considering the possible degeneration of internal motions in torsional rotations. The thermodynamic analysis indicated that the Ga gas phase species formed in the highest concentration at the standard GaN deposition temperature (1300 K) is GaNH2, followed by GaH and Ga. The diatomic GaN gas phase species, often considered to be the main precursor to the film growth, is predicted to be unstable with respect to GaNH2. Among the gas phase species containing two Ga atoms, the most stable are GaNHGaH(NH2)3, GaNHGaH2(NH2)2, and GaNHGa(NH2)4, thus indicating that the substitution of the methyl groups of the precursor with H or amino groups is thermodynamically favored. Several kinetic routes leading to the formation of these species were examined. It was found that the condensation of Ga(R1)x(R2)3-x species, with R1 and R2 being either CH3, NH2, or H, is a fast process, characterized by the formation of a precursor state whose decomposition to products requires overcoming submerged energy barriers. It is suggested that these species play a key role in the formation of the first GaN nuclei, whose successive growth leads to the formation of GaN powders. A kinetic analysis performed using a fluid dynamic model allowed us to identify the main reactive routes of this complex system.
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http://dx.doi.org/10.1021/acs.jpca.5b01425DOI Listing
July 2015

Molecular modeling of the affinity chromatography of monoclonal antibodies.

Methods Mol Biol 2015 ;1286:321-35

Department of Chimica Materiali e Ingegneria Chimica, G. Natta, Politecnico di Milano, via Mancinelli 7, Milano, 20131, Italy.

Molecular modeling is a methodology that offers the possibility of studying complex systems such as protein-ligand complexes from an atomistic point of view, making available information that can be difficultly obtained from experimental studies. Here, a protocol for the construction of molecular models of the interaction between antibodies and ligands that can be used for an affinity chromatography process is presented. The outlined methodology focuses mostly on the description of a procedure that may be adopted to determine the structure and free energy of interaction between the antibody and the affinity ligand. A procedure to extend the proposed methodology to include the effect of the environment (buffer solution, spacer, support matrix) is also briefly outlined.
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http://dx.doi.org/10.1007/978-1-4939-2447-9_25DOI Listing
December 2015

Glycosaminoglycans in the human cornea: age-related changes.

Ophthalmol Eye Dis 2015 27;7:1-5. Epub 2015 Jan 27.

Section of Human Anatomy, Sapienza University of Rome, Rome, Italy.

Aim: To investigate possible age-related changes in glycosaminoglycans (GAGs) in the human cornea. The substances today called GAGs were previously referred to as mucopolysaccharides.

Methods: Samples of human cornea were taken from 12 younger (age 21 ± 1.2) and 12 older (age 72 ± 1.6) male subjects. Samples were weighed, homogenized, and used for biochemical and molecular analyses. All the quantitative results were statistically analyzed.

Results: The human cornea appears to undergo age-related changes, as evidenced by our biochemical and molecular results. The total GAG and hyaluronic acid counts were significantly higher in the younger subjects than in the older subjects. The sulfated heavy GAGs, such as chondroitin, dermatan, keratan, and heparan sulfate, were lower in the younger subjects than in the older subjects.

Discussion: GAGs of the human cornea undergo numerous age-related changes. Their quantity is significantly altered in the elderly in comparison with younger subjects. GAGs play an important role in age-related diseases of the human cornea.
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http://dx.doi.org/10.4137/OED.S17204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4310673PMC
February 2015

Potential regulatory molecules in the human trabecular meshwork of patients with glaucoma: immunohistochemical profile of a number of inflammatory cytokines.

Mol Med Rep 2015 Feb 27;11(2):1384-90. Epub 2014 Oct 27.

Department of Sensory Organs, Sapienza University of Rome, Rome 00161, Italy.

Glaucoma occurs when there are imbalances between the production and the drainage of the eye liquid. The vast majority of the aqueous humor leaves the eye through the trabecular meshwork (TM). The cause of hypertonicity may be due to an alteration in the thickness of the TM. In the majority of cases the molecular changes that determine primary open‑angle glaucoma (POAG) are unclear. However, it has been hypothesized that the significant increase in the extracellular matrix (ECM) of the fibrillary bands in the TM is associated with possible inflammatory conditions. In this study the tissue distribution of interleukin (IL)‑6, IL‑1β, transforming growth factor-β1 (TGF‑β1), vascular endothelial growth factor (VEGF) and tumor necrosis factor α (TNF‑α) was analyzed in TM samples from patients with POAG by immunohistochemistry. Seven specimens from patients with POAG and three control tissues were analyzed by immunohistochemistry using specific antibodies against these cytokines. Morphological changes in the TM, such as increased cell content, macrophages, fibrosis and accumulation of neutrophils, were observed by transmission electron microscopy. In human TM tissues, an evident immunoreactivity for IL‑6, IL‑1β and TNF‑α was observed in patients with POAG when compared with the control subjects, indicating that these cytokines may be correlated with disease activity. TM endothelial cells secrete a number of factors and cytokines that modulate the functions of the cells and the ECM of the conventional outflow pathway. In the TM in glaucoma, macrophages produce cytokines, including IL‑6, IL‑1β and TNF‑α, leading to an acute inflammatory response and recruitment of other immune cells, including T lymphocytes. In addition, TGF‑β1 regulates and induces the expression of IL‑6 in TM that indirectly induces angiogenesis by stimulating VEGF expression. The present results support previous evidence that suggests that growth factors and cytokines can induce ECM remodelling and alter cytoskeletal interactions in the TM.
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http://dx.doi.org/10.3892/mmr.2014.2772DOI Listing
February 2015

Investigation of the initial steps of the electrochemical reduction of CO2 on Pt electrodes.

J Phys Chem A 2014 Sep 12;118(38):8676-88. Epub 2014 Sep 12.

Dept. di Chimica Materiali e Ingegneria chimica "G. Natta", Politecnico di Milano , via Mancinelli 7, 20131 Milano, Italy.

The initial steps of the electrochemical reduction of CO2 at Pt electrodes were computationally investigated at the molecular level. Simulations were performed with density functional theory using the B3LYP functional and effective core potential basis sets. The surface was modeled through two clusters comprising 13 and 20 atoms. An implicit solvation model was used to describe solvation effects for two different solvents: water and acetonitrile. It was found that CO2 adsorption is highly favored on negatively charged clusters and takes place passing from a well-defined transition state. The computational evidence suggests that the electrodic CO2 adsorption reaction may be described as a concerted process in which an electron-transfer reaction takes place contextually to CO2 adsorption. Also, the present results suggest that the formation of the CO2(•–) aqueous species is significantly unfavored from an energetic standpoint and that its main fate, if formed, would be most likely that of getting adsorbed again on the Pt surface. The calculation of the pKa of adsorbed CO2(–) showed that its protonation reaction is thermodynamically favored in most electrochemical conditions used for CO2 reduction. Also, it was found that the free-energy difference between adsorbed formate and adsorbed COOH favors the latter, suggesting that the interconversion kinetics of these two species at a Pt surface may play an important role in determining the system reactivity. A tentative global mechanism able to describe the CO2 reactivity on Pt surfaces is proposed.
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http://dx.doi.org/10.1021/jp505347kDOI Listing
September 2014

Neuro-immune modulation of the thymus microenvironment (review).

Int J Mol Med 2014 Jun 20;33(6):1392-400. Epub 2014 Mar 20.

Department of Sensory Organs, Sapienza University of Rome, Ι-00185 Rome, Italy.

The thymus is the primary site for T-cell lympho-poiesis. Its function includes the maturation and selection of antigen specific T cells and selective release of these cells to the periphery. These highly complex processes require precise parenchymal organization and compartmentation where a plethora of signalling pathways occur, performing strict control on the maturation and selection processes of T lymphocytes. In this review, the main morphological characteristics of the thymus microenvironment, with particular emphasis on nerve fibers and neuropeptides were assessed, as both are responsible for neuro-immune‑modulation functions. Among several neurotransmitters that affect thymus function, we highlight the dopaminergic system as only recently has its importance on thymus function and lymphocyte physiology come to light.
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http://dx.doi.org/10.3892/ijmm.2014.1709DOI Listing
June 2014

The opioid neuropeptides in uterine fibroid pseudocapsules: a putative association with cervical integrity in human reproduction.

Gynecol Endocrinol 2013 Nov 12;29(11):982-8. Epub 2013 Aug 12.

Department of Obstetric & Gynecology, Santa Maria Hospital , Bari , Italy .

The myoma pseudocapsule (MP) is a fibro-vascular network rich of neurotransmitters, as a neurovascular bundle, surrounding fibroid and separating myoma from myometrium. We investigated the distribution of the opioid neuropeptides, as enkephalin (ENK) and oxytocin (OXT), in the nerve fibers within MP and their possible influence in human reproduction in 57 women. An histological and immunofluorescent staining of OXT and ENK was performed on nerve fibers of MP samples from the fundus, corpus and isthmian-cervical regions, with a successive morphometric quantification of OXT and ENK. None of the nerve fibers in the uterine fundus and corpus MPs contained ENK and the nerve fibers in the isthmian-cervical region demonstrated an ENK value of up to 94 ± 0.7 CU. A comparatively lower number of OXT-positive nerve fibers were found in the fundal MP (6.3 ± 0.8 CU). OXT-positive nerve fibers with OXT were marginally increased in corporal MP (15.0 ± 1.4 CU) and were substantially higher in the isthmian-cervical region MP (72.1 ± 5.1 CU) (p < 0.01). The distribution of OXY neurofibers showed a slight into the uterine corpus, while are highly present into the cervico-isthmic area, with influence on reproductive system and sexual disorders manifesting after surgical procedures on the cervix.
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http://dx.doi.org/10.3109/09513590.2013.824958DOI Listing
November 2013

Analysis of the gas phase reactivity of chlorosilanes.

J Phys Chem A 2013 Jun 18;117(25):5221-31. Epub 2013 Jun 18.

Dipartimento di Chimica, Materiali e Ingegneria Chimica Giulio Natta, Politecnico di Milano via Mancinelli 7, 20131 Milano, Italy.

Trichlorosilane is the most used precursor to deposit silicon for photovoltaic applications. Despite of this, its gas phase and surface kinetics have not yet been completely understood. In the present work, it is reported a systematic investigation aimed at determining what is the dominant gas phase chemistry active during the chemical vapor deposition of Si from trichlorosilane. The gas phase mechanism was developed calculating the rate constant of each reaction using conventional transition state theory in the rigid rotor-harmonic oscillator approximation. Torsional vibrations were described using a hindered rotor model. Structures and vibrational frequencies of reactants and transition states were determined at the B3LYP/6-31+G(d,p) level, while potential energy surfaces and activation energies were computed at the CCSD(T) level using aug-cc-pVDZ and aug-cc-pVTZ basis sets extrapolating to the complete basis set limit. As gas phase and surface reactivities are mutually interlinked, simulations were performed using a microkinetic surface mechanism. It was found that the gas phase reactivity follows two different routes. The disilane mechanism, in which the formation of disilanes as reaction intermediates favors the conversion between the most stable monosilane species, and the radical pathway, initiated by the decomposition of Si2HCl5 and followed by a series of fast propagation reactions. Though both mechanisms are active during deposition, the simulations revealed that above a certain temperature and conversion threshold the radical mechanism provides a faster route for the conversion of SiHCl3 into SiCl4, a reaction that favors the overall Si deposition process as it is associated with the consumption of HCl, a fast etchant of Si. Also, this study shows that the formation of disilanes as reactant intermediates promotes significantly the gas phase reactivity, as they contribute both to the initiation of radical chain mechanisms and provide a catalytic route for the conversion between the most stable monosilanes.
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http://dx.doi.org/10.1021/jp403529xDOI Listing
June 2013

Monoamine oxidase enzymes and oxidative stress in the rat optic nerve: age-related changes.

Int J Exp Pathol 2012 Dec 22;93(6):401-5. Epub 2012 Oct 22.

Center of Ocular Electrophysiology, Department of Sense Organs, Sapienza University of Rome, Rome, Italy.

In this study, age-related changes in the monoamine oxidases (MAO) were studied in the optic nerve (ON) of both young and aged male rats. The aim of the study was to assess the role of MAO in age-related changes in the rat ON and explain the mechanisms of neuroprotection mediated by MAO-B-specific inhibitors. Fifteen three month old and fifteen 26 month old Sprague-Dawley rats were used. The animals were killed by terminal anaesthesia. Staining of MAO, quantitative analysis of images, biochemical assays and statistical analysis of data were carried out. Samples of the ON were washed in water, fixed in Bowen fluid, dehydrated and embedded in Entellan. Histological sections were stained for MAO-enzymatic activities. The specificity of the reaction was evaluated by incubating control sections in a medium either without substrate or without dye. The quantitative analysis of images was carried out at the same magnification and the same lighting using a Zeiss photomicroscope. The histochemical findings were compared with the biochemical results. After enzymatic staining, MAO could be demonstrated in the ON fibres of both young and aged animals; however, MAO were increased in the nerve fibres of the elderly rats. These morphological findings were confirmed biochemically. The possibility that age-related changes in MAO levels may be attributed to impaired energy production mechanisms and/or represent the consequence of reduced energy needs is discussed.
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http://dx.doi.org/10.1111/j.1365-2613.2012.00832.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521895PMC
December 2012

Surgical management of neurovascular bundle in uterine fibroid pseudocapsule.

JSLS 2012 Jan-Mar;16(1):119-29

Department of Obstetrics and Gynaecology, Vito Fazzi Hospital, Lecce, Italy.

The uterine fibroid pseudocapsule is a fibro-neurovascular structure surrounding a leiomyoma, separating it from normal peripheral myometrium. The fibroid pseudocapsule is composed of a neurovascular network rich in neurofibers similar to the neurovascular bundle surrounding a prostate. The nerve-sparing radical prostatectomy has several intriguing parallels to myomectomy. It may serve either as a useful model in modern fibroid surgical removal, or it may accelerate our understanding of the role of the fibrovascular bundle and neurotransmitters in the healing and restoration of reproductive potential after intracapsular myomectomy. Surgical innovations, such as laparoscopic or robotic myomectomy applied to the intracapsular technique with magnification of the fibroid pseudocapsule surrounding a leiomyoma, originated from the radical prostatectomy method that highlighted a careful dissection of the neurovascular bundle to preserve sexual functioning after prostatectomy. Gentle uterine leiomyoma detachment from the pseudocapsule neurovascular bundle has allowed a reduction in uterine bleeding and uterine musculature trauma with sparing of the pseudocapsule neuropeptide fibers. This technique has had a favorable impact on functionality in reproduction and has improved fertility outcomes. Further research should determine the role of the myoma pseudocapsule neurovascular bundle in the formation, growth, and pathophysiological consequences of fibroids, including pain, infertility, and reproductive outcomes.
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http://dx.doi.org/10.4293/108680812X13291597716302DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407432PMC
September 2012

NT, NPY and PGP 9.5 presence in myomeytrium and in fibroid pseudocapsule and their possible impact on muscular physiology.

Gynecol Endocrinol 2013 Feb;29(2):177-81

Department of Obstetric & Gynecology, Santa Maria Hospital, Bari, Italy.

The uterine myoma pseudocapsule is a neurovascular bundle surrounding fibroid, containing neuropeptides, probably involved in uterine scar healing. We studied neurotensin (NT), neuropeptide tyrosine (NPY), and protein gene product 9.5 (PGP 9.5) nerve fibres in the pseudocapsule neurovascular bundle of intramural uterine fibroids on 67 no pregnant women by intracapsular myomectomy sparing the neurovascular bundle, sampling full thickness specimens of the pseudocapsule of uterine fibroids (PUF) and normal myometrium (NM) obtained from the fundus uteri (FU) and the uterine body (UB). The samples were sent for histological and immunofluorescent analyses and compared by morphometrical quantification. The Conventional Unit (C.U.) difference of NT, NPY, and PGP 9.5 nerve fibres was statistically analyzed. Our results showed that NT, NPY, and PGP 9.5 neurofibers are almost equally present in PUF as in NM of a no pregnant uterus. As all of these neuropeptides are present in the uterine muscle and can affect muscle contractility, uterine peristalsis and muscular healing. A myomectomy respecting the pseudocapsule neurofibers should facilitate smooth muscle scarring and promote restoration of normal uterine peristalsis with a possible positive influence on fertility.
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http://dx.doi.org/10.3109/09513590.2012.708803DOI Listing
February 2013

Analysis of nerve supply pattern in thoracic duct in young and elderly men.

Lymphat Res Biol 2012 Jun 27;10(2):46-52. Epub 2012 Apr 27.

Anatomia Umana, Scuola di Scienza del Farmaco e dei Prodotti della Salute, Università di Camerino, Camerino, Italy.

Background: Analysis of the innervation pattern of the thoracic duct in young and elderly human subjects has been performed. The subdivision of the vessels in cervical and lumbar region were taken in consideration.

Methods And Results: Immunostaining for general nerve fibers with a PGP 9.5 marker disclosed a diffuse innervation of the thoracic duct in young subjects, which was strongly reduced in elderly subjects. In young subjects, tyrosine hydroxylase (TH) and neuropeptide Y (NPY) immunoreactive fibers, markers of noradrenergic postganglionic sympathetic fibers, were frequent; choline acetyltransferase (ChAT) immunoreactive fibers, marker of cholinergic parasympathetic nerve fibers, were also well represented. Therefore, the influence of sympathetic and parasympathetic nerve systems on the thoracic duct can be confirmed. The immunoreactivity of vasoactive intestinal peptide (VIP), a neuropeptide frequently present in cholinergic parasympathetic nerve fibers, was scarcely present. Dopamine-positive fibers were observed in few short nerve fibers. Substance P (SP)-positive fibers were widely distributed in the medial and intimal smooth muscle layers, suggesting their involvement as contractile modulating fibers and sensitive fibers. In elderly subjects, an evident reduction of all specific nerve fibers analyzed was detected, the ChAT-positive fibers being the most affected.

Conclusions: The lymphatic vessel thoracic duct is able to regulate hydrodynamic lymph flow by intrinsic contraction of its smooth muscle layer. Therefore, analysis of the thoracic duct innervation pattern may be important in assessing the regulation of vessel contraction. These findings called attention to the reduction of lymphatic drainage functionality affecting fluid balance in the elderly.
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http://dx.doi.org/10.1089/lrb.2011.0014DOI Listing
June 2012

Trabecular meshwork in normal and pathological eyes.

Ultrastruct Pathol 2012 Apr;36(2):102-7

Department of Science Cardiovascular Respiratory and Morphological Sciences, Sapienza University of Rome, Rome, Italy.

Purpose: The impact of glycosaminoglycans on intraocular pressure in glaucoma patients and in healthy young or aging subjects is explored.

Materials And Methods: Thirty small autoptic samples were harvested from the tissue localized around the iridocorneal angle of the eye, taking care not to cause aesthetic damage. The samples came from three groups (young, old, and subjects with glaucoma). All samples were divided in two fragments and both were used for morphological and biochemical analyses. Quantitative data were obtained from image analysis to correlate with biochemical values. All results were statistically analyzed.

Results: The findings show the following changes of iridocorneal angle are caused by glycosaminoglycans both in aging and in glacoumatous patients: (1) deposition of fibrous granular material and increased electron density of the structures close to the iridocorneal angle; and (2) strong decrease of hyaluronic acid content and increase of sulfated glycosaminoglycans.

Conclusions: Similar to what happens in other tissues in the body, glycosaminoglycans of the human iridocorneal angle undergo physiological and pathological changes. The trabecular meshwork is the structure responsible for the regulation of the aqueous humor outflow that is often altered in primary open-angle glaucoma patients.
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http://dx.doi.org/10.3109/01913123.2011.634090DOI Listing
April 2012
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