Publications by authors named "Maddalena P"

59 Publications

Giant O-Induced Photoluminescence Modulation in Hierarchical Titanium Dioxide Nanostructures.

ACS Sens 2017 Jan 4;2(1):61-68. Epub 2017 Jan 4.

Institute of Applied Sciences and Intelligent Systems (CNR-ISASI) , Via Campi Flegrei 34, I-80078 Pozzuoli, Italy.

We demonstrate exceptionally large modulation of PL intensity in hierarchical titanium dioxide (TiO) nanostructures exposed to molecular oxygen (O). Optical responsivities up to about 1100% at 20% O concentrations are observed in hyperbranched anatase-phase hierarchical structures, outperforming those obtainable by commercial TiO nanopowders (up to a factor of ∼7 for response to synthetic air) and significantly improving the ones typically reported in PL-based opto-chemical gas sensing using MOXs. The improved PL response is discussed in terms of the specific morphology of hierarchical structures, characterized by simultaneous presence of small nanoparticles, large surface areas, and large voids. These characteristics guarantee an optimal interplay between photogenerated charges, PL-active centers, and adsorbed gas molecules. The results highlight the potentialities offered by hierarchical structures based on TiO or other MOXs and open interesting scenarios toward the development of all-optical and/or hybrid (opto/electrical) chemical sensors with improved sensitivity.
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http://dx.doi.org/10.1021/acssensors.6b00432DOI Listing
January 2017

Graphene oxide prepared by graphene nanoplatelets and reduced by laser treatment.

Nanotechnology 2017 Jun 10;28(22):224002. Epub 2017 Apr 10.

Institute for Polymers, Composites and Biomaterials, National Research Council, UOS Napoli/Portici, Piazzale Enrico Fermi, 1, I-80055, Portici, Italy.

The Hummers' method for graphite oxide (GO) preparation has been applied to graphite nanoplatelets, in order to achieve higher reaction yield and faster kinetics. Aqueous GO solutions have been used to produce uniform GO films on a polyethylene terephthalate substrate, generating graphene patterns in a controlled way (widths of a few tens of microns). The reduction of GO deposited on the polymeric substrate has been performed by using a Nd:YVO continuous-wave frequency-duplicated laser. Spectroscopic and diffractometric characterizations (FT-IR, visible-NIR, Raman, XPS, and XRD) have shown that the reduction process induced by the laser annealing technique is mainly due to dehydration of the GO layers. It has been obtained by means of a suitable laser optical apparatus, a controlled reduction of GO without damaging the substrate, and precise writing of micro-tracks that can be used as electrically and thermally conductive patterns.
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http://dx.doi.org/10.1088/1361-6528/aa6c3cDOI Listing
June 2017

Anomalous evolution of broadband optical absorption reveals dynamic solid state reorganization during eumelanin build-up in thin films.

Sci Rep 2017 03 31;7(1):522. Epub 2017 Mar 31.

INFN, Sezione di Napoli, Via Cintia, 80126, Napoli, Italy.

The origin of eumelanin optical properties remains a formidable conundrum preventing a detailed understanding of the complex photo-protective role of these widespread natural pigments and the rational design of innovative bioinspired materials for optoelectronic applications. Here we report the unusual kinetic and thickness-dependent evolution of the optical properties of black eumelanin polymers generated by spontaneous aerial polymerization of 5,6-dihydroxyindole (DHI) thin films (0.1-1 μm), consistent with peculiar solid state reorganization mechanisms governing broadband absorption. The complete reversal of eumelanin UV-visible transmittance spectrum curvature on passing from 0.2 to 0.5 μm thick films, the marked increase in visible extinction coefficients with increasing film thickness and the higher UV extinction coefficients in slowly vs. rapidly generated polymers concur to support distinct dynamic regimes of solid-state molecular reorganization at the nanoscale level and to do affect the development of broadband visible absorption. Solid state control of molecular reorganization disclosed herein may delineate new rational strategies for tuning optical properties in eumelanin thin films for optoelectronic applications.
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http://dx.doi.org/10.1038/s41598-017-00597-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5428701PMC
March 2017

Spin-to-orbital angular momentum conversion in dielectric metasurfaces: erratum.

Opt Express 2017 02;25(4):4239

We would like to clarify our paper [Opt. Express25, 377 (2017)] abstract sentence "These beams carry orbital angular momentum proportional to the number of intertwined helices constituting the wavefront."
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http://dx.doi.org/10.1364/OE.25.004239DOI Listing
February 2017

Spin-to-orbital angular momentum conversion in dielectric metasurfaces.

Opt Express 2017 Jan;25(1):377-393

Vortex beams are characterized by a helical wavefront and a phase singularity point on the propagation axis that results in a doughnut-like intensity profile. These beams carry orbital angular momentum proportional to the number of intertwined helices constituting the wavefront. Vortex beams have many applications in optics, such as optical trapping, quantum optics and microscopy. Although beams with such characteristics can be generated holographically, spin-to-orbital angular momentum conversion has attracted considerable interest as a tool to create vortex beams. In this process, the geometrical phase is exploited to create helical beams whose handedness is determined by the circular polarization (left/right) of the incident light, that is by its spin. Here we demonstrate high-efficiency Spin-to-Orbital angular momentum-Converters (SOCs) at visible wavelengths based on dielectric metasurfaces. With these SOCs we generate vortex beams with high and fractional topological charge and show for the first time the simultaneous generation of collinear helical beams with different and arbitrary orbital angular momentum. This versatile method of creating vortex beams, which circumvents the limitations of liquid crystal SOCs and adds new functionalities, should significantly expand the applications of these beams.
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http://dx.doi.org/10.1364/OE.25.000377DOI Listing
January 2017

Simple and Flexible Model for Laser-Driven Antibody-Gold Surface Interactions: Functionalization and Sensing.

ACS Appl Mater Interfaces 2016 Aug 9;8(33):21762-9. Epub 2016 Aug 9.

Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore.

Interactions between biomolecules and between substrates and biomolecules is a crucial issue in physics and applications to topics such as biotechnology and organic electronics. The efficiency of bio- and mechanical sensors, of organic electronics systems, and of a number of other devices critically depends on how molecules are deposited on a surface so that these acquire specific functions. Here, we tackle this vast problem by developing a coarse grained model of biomolecules having a recognition function, such as antibodies, capable to quantitatively describe in a simple manner essential phenomena: antigen-antibody and antibody substrate interactions. The model is experimentally tested to reproduce the results of a benchmark case, such as (1) gold surface functionalization with antibodies and (2) antibody-antigen immune-recognition function. The agreement between experiments and model prediction is excellent, thus unveiling the mechanism for antibody immobilization onto metals at the nanoscale in various functionalization schemes. These results shed light on the geometrical packing properties of the deposited molecules, and may open the way to a novel coarse-grained based approach to describe other processes where molecular packing is a key issue with applications in a huge number of fields from nano- to biosciences.
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http://dx.doi.org/10.1021/acsami.6b04449DOI Listing
August 2016

Observation of a photoinduced, resonant tunneling effect in a carbon nanotube-silicon heterojunction.

Beilstein J Nanotechnol 2015 10;6:704-10. Epub 2015 Mar 10.

INFN, Sezione di Bari and Dipartimento di Fisica, Università degli Studi di Bari, Via Amendola 173, 70126 Bari, Italy.

A significant resonant tunneling effect has been observed under the 2.4 V junction threshold in a large area, carbon nanotube-silicon (CNT-Si) heterojunction obtained by growing a continuous layer of multiwall carbon nanotubes on an n-doped silicon substrate. The multiwall carbon nanostructures were grown by a chemical vapor deposition (CVD) technique on a 60 nm thick, silicon nitride layer, deposited on an n-type Si substrate. The heterojunction characteristics were intensively studied on different substrates, resulting in high photoresponsivity with a large reverse photocurrent plateau. In this paper, we report on the photoresponsivity characteristics of the device, the heterojunction threshold and the tunnel-like effect observed as a function of applied voltage and excitation wavelength. The experiments are performed in the near-ultraviolet to near-infrared wavelength range. The high conversion efficiency of light radiation into photoelectrons observed with the presented layout allows the device to be used as a large area photodetector with very low, intrinsic dark current and noise.
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http://dx.doi.org/10.3762/bjnano.6.71DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4362292PMC
March 2015

Instability-induced pattern formation of photoactivated functional polymers.

Proc Natl Acad Sci U S A 2014 Dec 17;111(48):17017-22. Epub 2014 Nov 17.

School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138;

Since the pioneering work of Turing on the formation principles of animal coat patterns [Turing AM (1952) Phil Trans R Soc Lond B 237(641):37-72], such as the stripes of a tiger, great effort has been made to understand and explain various phenomena of self-assembly and pattern formation. Prominent examples are the spontaneous demixing in emulsions, such as mixtures of water and oil [Herzig EM, et al. (2007) Nat Mater 6:966-971]; the distribution of matter in the universe [Kibble TWB (1976) J Phys A: Math Gen 9(8):1387]; surface reconstruction in ionic crystals [Clark KW, et al. (2012) Nanotechnol 23(18):185306]; and the pattern formation caused by phase transitions in metal alloys, polymer mixtures and binary Bose-Einstein condensates [Sabbatini J, et al. (2011) Phys Rev Lett 107:230402]. Photoactivated pattern formation in functional polymers has attracted major interest due to its potential applications in molecular electronics and photoresponsive systems. Here we demonstrate that photoactivated pattern formation on azobenzene-containing polymer films can be entirely explained by the physical concept of phase separation. Using experiments and simulations, we show that phase separation is caused by an instability created by the photoactivated transitions between two immiscible states of the polymer. In addition, we have shown in accordance with theory, that polarized light has a striking effect on pattern formation indicated by enhanced phase separation.
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http://dx.doi.org/10.1073/pnas.1409718111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4260583PMC
December 2014

Holographic patterning of graphene-oxide films by light-driven reduction.

Opt Lett 2014 Jul;39(14):4263-6

We report on the patterning and reduction of graphene-oxide films by holographic lithography. Light reduction can be used to engineer low-cost graphene-based devices by performing a local conversion of insulating oxide into the conductive graphene. In this work, computer-generated holograms have been exploited to realize complex graphene patterns in a single shot, different from serial laser writing or mask-based photolithographic processes. The technique has been further improved by achieving speckle noise reduction: submicron and diffraction-limited features have been obtained. In addition we have also demonstrated that the gray-scale lithography capability can be used to obtain different reduction levels in a single exposure.
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http://dx.doi.org/10.1364/OL.39.004263DOI Listing
July 2014

Acute effect on satiety, resting energy expenditure, respiratory quotient, glucagon-like peptide-1, free fatty acids, and glycerol following consumption of a combination of bioactive food ingredients in overweight subjects.

J Am Coll Nutr 2013 ;32(1):41-9

Department of Applied Health Sciences, Section of Human Nutrition and Dietetics, Faculty of Medicine, Endocrinology and Nutrition Unit, University of Pavia, Pavia, Italy.

Objective: A combination of bioactive food ingredients (capsaicinoids, epigallocatechin gallate, piperin, and l-carnitine, CBFI) may promote satiety and thermogenesis. The study was conducted in order to assess whether there is any effect on satiety, resting energy expenditure (REE), respiratory quotient, glucagon-like peptide-1 (GLP-1), free fatty acids (FFA) and glycerol release, following a standardized mixed meal with or without single consumption of a CBFI.

Design: An 8-week randomized double-blind placebo-controlled trial.

Setting: Dietetic and Metabolic Unit, Azienda di Servizi alla Persona, University of Pavia and "Villa delle Querce" Clinical Rehabilitation Institute, Rome, Italy.

Participants: Thirty-seven overweight adults (body mass index [BMI]: 25-35).

Intervention: Nineteen overweight subjects were included in the supplemented group (14 women, 5 men; age 46.4 ± 6.4; BMI: 30.5 ± 3.3) and 18 in the placebo group (13 women, 5 men; age 40.8 ± 11.5; BMI: 30.1 ± 2.6). Satiety was assessed using 100-mm visual analogue scales (VAS) and the area under the curve was calculated.

Results: All measured parameters increased significantly in comparison with baseline in response to meal, both with CBFI and with placebo. However, throughout the study day, the supplemented group experienced a significantly greater increase than the placebo group in their sensation of satiety following acute administration of the supplement.

Conclusion: CBFI may therefore be of great value in the treatment of overweight patients by increasing satiety and stimulating thermogenesis.
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http://dx.doi.org/10.1080/07315724.2013.767667DOI Listing
February 2014

Molecular model for light-driven spiral mass transport in azopolymer films.

Phys Rev Lett 2013 Apr 5;110(14):146102. Epub 2013 Apr 5.

CNR-SPIN, Complesso Universitario di Monte Sant'Angelo, 80126 Napoli, Italy and Dipartimento di Fisica, Università di Napoli "Federico II," Complesso Universitario di Monte Sant'Angelo, 80126 Napoli, Italy.

Azopolymer films exposed to nonuniform illumination exhibit a phenomenon of light-induced mass transport, leading to the formation of permanent relief patterns on the film surface. Its underlying microscopic mechanism remains unclear, despite many years of research effort. Here we introduce a model of the mass migration process based on anisotropic light-driven molecular diffusion. A key ingredient of our model is an enhanced molecular diffusion in proximity of the free polymer surface, which is essential for explaining, in particular, the recently observed spiral-shaped reliefs resulting from vortex-beam illumination.
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http://dx.doi.org/10.1103/PhysRevLett.110.146102DOI Listing
April 2013

Improvement in insulin resistance and favourable changes in plasma inflammatory adipokines after weight loss associated with two months' consumption of a combination of bioactive food ingredients in overweight subjects.

Endocrine 2013 Oct 28;44(2):391-401. Epub 2012 Dec 28.

Department of Applied Health Sciences, Section of Human Nutrition and Dietetics, Faculty of Medicine, University of Pavia, Azienda di Servizi alla Persona di Pavia, Servizio Endocrino Nutrizionale, Istituto di Riabilitazione "Santa Margherita", Via Emilia 12, Pavia, Italy,

This randomized, double blind, placebo-controlled, 8 week trial assessed the efficacy on metabolic changes produced by a consumption of a combination of bioactive food ingredients (epigallocatechin gallate, capsaicins, piperine and L-carnitine) versus a placebo, as part of a therapeutic 'lifestyle change' diet, in 86 overweight subjects. Forty-one patients (2/14 F/M; age 43.7 ± 8.5; BMI 30.3 ± 3.5 kg/m(2)) were randomized to the supplemented group and 45 (29/16; age 40.7 ± 10.2; BMI 30.0 ± 2.7) to the control group. We observed that consumption of the dietary supplement was associated with a significantly greater decrease in insulin resistance, assessed by homostasis model assessment (p < 0.001), leptin/adiponectin ratio (p < 0.04), respiratory quotient (p < 0.008). LDL-cholesterol levels (p < 0.01). Moreover, statistically significant differences were recorded between the two groups in relation to urinary norepinephrine levels (p < 0.001). Leptin, ghrelin, C-reactive protein decreased and resting energy expenditure increased significantly in the supplemented group (p < 0.05, 0.03, 0.02 and 0,02 respectively), but not in the placebo group; adiponectin decreased significantly in the placebo group (0.001) but not in the supplemented group, although no statistical significance between the groups was elicited. BMI, fat mass (assessed by DXA) and vascular endothelial growth factor significantly decreased, whilst the resting energy expenditure/free fat mass significantly increased in both groups. In general, a greater change was recorded in the supplemented group compared to the placebo, although no statistically significant difference between the two groups was recorded. These results suggest that the combination of bioactive food ingredients studied might be useful for the treatment of obesity-related inflammatory metabolic dysfunctions.
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http://dx.doi.org/10.1007/s12020-012-9863-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3790246PMC
October 2013

Light-induced spiral mass transport in azo-polymer films under vortex-beam illumination.

Nat Commun 2012 ;3:989

CNR-SPIN and Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, Via Cintia, Napoli 80126, Italy.

When an azobenzene-containing polymer film is exposed to non-uniform illumination, a light-induced mass migration process may be induced, leading to the formation of relief patterns on the polymer-free surface. Despite many years of research effort, several aspects of this phenomenon remain poorly understood. Here we report the appearance of spiral-shaped relief patterns on the polymer film under the illumination of focused Laguerre-Gauss beams with helical wavefronts and an optical vortex at their axis. The induced spiral reliefs are sensitive to the vortex topological charge and to the wavefront handedness. These findings are unexpected because the doughnut-shaped intensity profile of Laguerre-Gauss beams contains no information about the wavefront handedness. We propose a model that explains the main features of this phenomenon through the surface-mediated interference of the longitudinal and transverse components of the optical field. These results may find applications in optical nanolithography and optical-field nanoimaging.
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http://dx.doi.org/10.1038/ncomms1996DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3432464PMC
November 2012

Primary bilateral malignant melanoma of the lower limbs.

Dermatol Reports 2011 Aug 15;3(2):e20. Epub 2011 Sep 15.

Department of Dermatology, University of Naples Federico II, Naples, Italy;

Malignant melanoma is the eighth most common cancer in European women. Its incidence is increasing rapidly and it has been demonstrated that this is related to sun exposure. Although few cases of bilateral uveal or choroidal melanoma are described in literature, there are no cases reporting bilateral cutaneous malignant melanoma. We report a singular case of a 43-year-old woman with two primary bilateral melanomas localized on the flexural surface of both legs.
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http://dx.doi.org/10.4081/dr.2011.e20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4211534PMC
August 2011

Recombination dynamics of deep defect states in zinc oxide nanowires.

Nanotechnology 2009 Apr 3;20(17):175706. Epub 2009 Apr 3.

CNR-INFM COHERENTIA, Complesso Universitario di Monte Sant'Angelo, Naples, Italy.

The recombination dynamics of defect states in zinc oxide nanowires has been studied by developing a general expression for time-resolved photoluminescence intensity based on a second-order approximation for the radiative and non-radiative recombination rates. The model allows us to determine the parameters that characterize the recombination from deep defect states (defect concentration, unimolecular lifetime and bimolecular coefficient) through multi-fitting analysis of time-resolved photoluminescence measurements. Analyses conducted on zinc oxide nanowires gave deep state concentrations of the order of 10(18) cm(-3) and unimolecular lifetimes and bimolecular recombination coefficient comparable to those typical of interband recombination in direct gap semiconductors. The consistency of a 'two-channel decay' model (double exponential decay) has been tested by means of a similar analysis procedure. The results suggest that double exponential fitting of time-resolved photoluminescence data of zinc oxide nanowires may be just a mere phenomenological tool which does not reflect the real recombination dynamics of the visible emission band.
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http://dx.doi.org/10.1088/0957-4484/20/17/175706DOI Listing
April 2009

Direct role of surface oxygen vacancies in visible light emission of tin dioxide nanowires.

J Chem Phys 2008 Dec;129(24):244710

CNR-INFM, CRS Coherentia, Via Cintia, I-80126 Napoli, Italy.

Tin dioxide (SnO(2)) nanowires exhibit a strong visible photoluminescence that is not observed in bulk crystalline SnO(2). To explain such effect, oxygen vacancies are often invoked without clarifying if they represent the direct origin of luminescence or if their presence triggers other radiative processes. Here we report an investigation of the nature of the visible light emission in SnO(2) nanowires, showing that both experimental and theoretical ab initio analyses support the first hypothesis. On the basis of photoluminescence quenching analysis and of first-principles calculations we show that surface bridging oxygen vacancies in SnO(2) lead to formation of occupied and empty surface bands whose transition energies are in strong agreement with luminescence features and whose luminescence activity can be switched off by surface adsorption of oxidizing molecules. Finally, we discuss how such findings may explain the decoupling between "electrical-active" and "optical-active" states in SnO(2) gas nanosensors [G. Faglia et al., Appl. Phys. Lett. 86, 011923 (2005)].
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http://dx.doi.org/10.1063/1.3041775DOI Listing
December 2008

Cerebellar hemorrhage in extremely low birth weight infants: incidence, risk factors, and impact on long-term outcomes.

Neonatal Netw 2008 Nov-Dec;27(6):387-96

Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.

Improvements in neuroimaging technology and techniques have contributed to the increased recognition of cerebellar hemorrhage (CBH) in the prererm infant. Studies have indicated that the extremely low birth weight (ELBW) infant (< 1,000 g) is at highest risk for this injury. Associated risk factors include a constellation of antenaral, intrapartum, and neonatal factors, with immaturity, fetal distress, and cardiorespiratory instability in the early neonatal course as significant contributors. The long-term impact of CBH for the ELBW infant is not fully understood, but recent reports suggest that, in addition to motor impairments, deficits in cognitive, language, and social-behavioral function are also apparent. This article reviews the current state of knowledge of cerebellar development, risk factors for injury, and long-term developmental consequences of injury. Implications for nursing practice, education, and research are discussed.
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http://dx.doi.org/10.1891/0730-0832.27.6.387DOI Listing
February 2009

Marine diatoms as optical biosensors.

Biosens Bioelectron 2009 Feb 20;24(6):1580-4. Epub 2008 Aug 20.

Unit of Naples-Institute for Microelectronics and Microsystems, Naples, Italy.

We have chemically modified the frustules of the marine diatom Coscinodiscus concinnus Wm. Smith to properly bind a highly selective bioprobe such as an antibody. By measuring the changes in the photoluminescence emission of diatoms frustules, we have monitored the molecular recognition event between the antibody and its ligand: the dissociation constant estimated is of the same order of that measured by standard Biacore. The nanostructured silica frustules, a low-cost and natural available material, have shown high sensitivity, equal to 1.2+/-0.2 nm microM(-1), and a detection limit of 100 nM, and thus are quite ideal candidates for lab-on-particle applications.
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http://dx.doi.org/10.1016/j.bios.2008.08.016DOI Listing
February 2009

Real-time monitoring of the surface relief formation on azo-polymer films upon near-field excitation.

J Microsc 2008 Feb;229(Pt 2):307-12

CNR-INFM CRS-COHERENTIA and Dipartimento di Scienze Fisiche, Università di Napoli Federico II, Via Cintia, I-80126 Napoli, Italy.

We use near-field optical microscopy to investigate the early state formation of photo-induced topographical structures on the free surface of azobenzene-containing polymers. The near-field technique is employed to monitor in real time the mass migration during the embossing of the surface of 50/50 copolymer films of polymethacrylate and polymethacrylate containing 3-methyl-4'-pentyloxy-azobenzene units. The dynamic of surface relief formation induced by light have been investigated as a function of the sample temperature. Furthermore, a formula derived from Navier-Stokes equations for classical laminar flow has been used to fit the mass displacement data during the embossing process. Excellent agreements between the experimental data and the fitting formula have been found for all the temperature considered.
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http://dx.doi.org/10.1111/j.1365-2818.2008.01905.xDOI Listing
February 2008

Testing the satisfaction and feasibility of a computer-based teaching module in the neonatal intensive care unit.

Adv Neonatal Care 2007 Feb;7(1):43-9

Sunnybrook & Women's College, Health Sciences Centre, 76 Grenville Street, Room 456, Toronto, Ontario, Canada M5A 1B2.

Purpose: To examine the satisfaction with and feasibility of a computer-based teaching module to teach healthcare professionals how to use and apply the Premature Infant Pain Profile (PIPP) to clinical scenarios.

Subjects: Sixty-eight healthcare professionals who were employed in the neonatal intensive care unit (NICU) on a full-time or part-time basis and had received an educational session regarding the PIPP.

Design And Methods: A pilot study using an exploratory descriptive design was used to answer: (1) How satisfied are healthcare professionals with the computer-based teaching module? and (2) What is the feasibility of a computer-based teaching module in the clinical setting? Satisfaction was measured using an investigator-developed 5-point Likert scale. Feasibility was measured in terms of time to complete the module, satisfaction with instructions and ability to navigate through the module, acceptability of the module as a teaching method, and format with the computer-based module.

Principal Results: Ninety percent of those sampled were very satisfied with the computer-based teaching method. Use of video and audio clips and photographs enhanced the learning process. Healthcare professionals identified the computer-based teaching method as an effective way of learning about the PIPP and thought that it was feasible to use within the clinical setting.

Conclusions: Computer-based teaching is a feasible method for educating NICU healthcare professionals about the PIPP. Additional research is required to examine the effectiveness of this teaching method on relevant patient outcomes such as pain management.
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http://dx.doi.org/10.1097/00149525-200702000-00012DOI Listing
February 2007

Field localization and enhanced Second-Harmonic Generation in silicon-based microcavities.

Opt Express 2007 Apr;15(7):4159-67

High-quality amorphous Silicon Nitride (a-Si(1-x)N(x):H) Fabry-Pérot microcavities can show resonant surface Second Harmonic Generation (SHG) effect. We consider two different layouts of planar microcavities with almost identical linear reflectance and show how the structure geometry can strongly affect SHG yield. In particular, a difference of more than one order of magnitude in the SHG intensity is observed when the fundamental beam is tuned at the cavity resonance frequency. We explain this finding on the basis of a theoretical model taking into account the spatial distribution of the electric fields of the pump and harmonic frequencies inside the structure. A satisfactory matching of experimental data with the theoretical model is obtained by considering the source of second-order nonlinearity as limited to surface contributions.
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http://dx.doi.org/10.1364/oe.15.004159DOI Listing
April 2007

Pain assessment and pharmacologic management for infants with NEC: a retrospective chart audit.

Neonatal Netw 2006 Sep-Oct;25(5):339-45

Sunnybrook Health Sciences Centre, Sunnybrook and Women's College Hospital, The Hospital for Sick Children, Toraonto, ON, Canada.

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http://dx.doi.org/10.1891/0730-0832.25.5.339DOI Listing
October 2006

Silicon infrared diffuser for wireless communication.

Appl Opt 2006 Sep;45(26):6746-9

Research Center Ente Nazionale Energia e Ambiente, Portici (Napoli), Italy.

We show what we believe to be a novel way to use silicon in infrared radio communication as a suitable material for the realization of optical diffusers in the range of 850-1600 nm. A crystalline silicon wafer is made porous by means of electrochemical etching. The porous silicon produced is optically characterized, and measurements report a high reflectance in the band of interest. We also study the angular distribution of diffused radiation by the porous silicon surface at different angles of incident radiation. Measurements show that radiation diffuses in a quasi-Lambertian manner, confirming the good performance of this material as an incident radiation diffuser.
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http://dx.doi.org/10.1364/ao.45.006746DOI Listing
September 2006

Lagrangian approach to light propagation in liquid crystals.

Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1995 Nov;52(5):5053-5060

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http://dx.doi.org/10.1103/physreve.52.5053DOI Listing
November 1995
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