Publications by authors named "Haisheng Lin"

21 Publications

  • Page 1 of 1

Co-hydrothermal carbonization of swine manure and cellulose: Influence of mutual interaction of intermediates on properties of the products.

Sci Total Environ 2021 May 29;791:148134. Epub 2021 May 29.

School of Material Science and Engineering, University of Jinan, Jinan 250022, China. Electronic address:

Co-hydrothermal carbonization (HTC) of livestock manure and biomass might improve the fuel properties of the hydrochar due to the high reactivity of the biomass-derived intermediates with the abundant oxygen-containing functionalities. However, the complicated compositions make it difficult to explicit the specific roles of the individual components of biomass played in the co-HTC process. In this study, cellulose was used for co-HTC with swine manure to investigate the influence on the properties of the hydrochar. The yield of hydrochar obtained from co-HTC reduced gradually with the cellulose proportion increased, and the solid yield was lower than the theoretical value. This was because the cellulose-derived intermediates favored the stability of the fragments from hydrolysis of swine manure. The increased temperature resulted in the reduction of the hydrochar yield whereas the prolonged time enhanced the formation of solid product. The interaction of the co-HTC intermediates facilitated the formation of O-containing species, thus making the solid more oxygen- and hydrogen-rich with a higher volatility. In addition, the co-HTC affected the evolution of functionalities like -OH and CO during the thermal treatment of the hydrochar and altered its morphology by stuffing the pores from swine manure-derived solid with the microspheres from HTC of cellulose. The interaction of the varied intermediates also impacted the formation of amines, ketones, carboxylic acids, esters, aromatics and the polymeric products in distinct ways.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148134DOI Listing
May 2021

Collagen Peptides Derived from Accelerate Wound Healing.

Molecules 2021 Mar 4;26(5). Epub 2021 Mar 4.

College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China.

Marine collagen peptides have high potential in promoting skin wound healing. This study aimed to investigate wound healing activity of collagen peptides derived from (SNCP). The effects of SNCP on promoting healing were studied through a whole cortex wound model in mice. Results showed that SNCP consisted of peptides with a molecular weight less than 5 kDa accounted for 81.95%, rich in Gly and Arg. SNCP possessed outstanding capacity to induce human umbilical vein endothelial cells (HUVEC), human immortalized keratinocytes (HaCaT) and human skin fibroblasts (HSF) cells proliferation and migration in vitro. In vivo, SNCP could markedly improve the healing rate and shorten the scab removal time, possessing a scar-free healing effect. Compared with the negative control group, the expression level of tumor necrosis factor-α, interleukin-1β and transforming growth factor-β1 (TGF-β1) in the SNCP group was significantly down-regulated at 7 days post-wounding ( < 0.01). Moreover, the mRNA level of mothers against decapentaplegic homolog 7 (Smad7) in SNCP group was up-regulated ( < 0.01); in contrast, type II TGF-β receptors, collagen I and α-smooth muscle actin were significantly down-regulated at 28 days ( < 0.01). These results indicate that SNCP possessed excellent activity of accelerating wound healing and inhibiting scar formation, and its mechanism was closely related to reducing inflammation, improving collagen deposition and recombination and blockade of the TGF-β/Smads signal pathway. Therefore, SNCP may have promising clinical applications in skin wound repair and scar inhibition.
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http://dx.doi.org/10.3390/molecules26051385DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961935PMC
March 2021

Pediatric anti-N-methyl-d-aspartate receptor encephalitis in southern China: Analysis of 111 cases.

J Neuroimmunol 2021 03 15;352:577479. Epub 2021 Jan 15.

Department of Neurology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9# Jin Sui Road, 510623 Guangzhou, Guangdong Province, PR China. Electronic address:

Objective: To study the clinical features of children diagnosed with anti-NMDAR encephalitis in southern China.

Methods: Clinical data of children diagnosed with anti-NMDAR encephalitis from October 2014 to June 2020 from one national regional medical center were analyzed. Neurological disability was assessed by modified Rankin Scale (mRS) throughout the course of disease.

Results: 111 children (M/F = 49/62; mean onset age = 6.8 y) with anti-NMDAR encephalitis were involved. Prodromal events occurred in 34.2% of patients with infectious events being the most common. Seizure was the most common initial symptom, though movement disorder served as the most common event throughout the course of disease. 9.9% of patients had overlapped with other neuronal autoantibodies. Electroencephalogram showed abnormalities with slow wave (100.0%), epileptic discharge (31.5%) and delta brush (8.1%) respectively. 41.4% of patients had abnormal brain MRI, with focal lesions being the most common. None patients had tumor. 80.9% of patients had good response to first line therapy (steroid plus immunoglobulin), while 14 patients accepted second-line therapy (Rituximab) and all had a good response. Boys were significantly more likely to need more course of steroid. 13.8% of patients relapsed. 2 male patients died. mRS score was significantly improved after treatment. 51.4% of patients had a full recovery and 81.7% had mRS score ≤ 2. The median mRS score of boys after treatment was higher than that of girls. Non-infectious prodromal event, past medical history, perivascular lesions in brain MRI, hospital stay, initial mRS score higher than 3, and RTX treatment were independent risk factors associated with poor prognosis, defined as mRS score > 2.

Conclusion: Of pediatric anti-NMDAR encephalitis in southern China: median onset age around 7 years; girls more common; boys might have poor outcome than girls; seizure or movement disorder respectively being most common onset or course symptom; a few overlapped with other neuronal autoantibodies; rare combined with tumor; most had a good response to immunotherapy and a good prognosis; relapse rate relatively high; fatality rate relatively low; some risk factors associated with poor prognosis.
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http://dx.doi.org/10.1016/j.jneuroim.2021.577479DOI Listing
March 2021

[Wound-healing acceleration of mice skin by extract and its mechanism].

Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2020 Jun;37(3):460-468

College of Food Science and Technology, Guangdong Ocean University, Zhanjiang, Guangdong 524088, P.R. China.

In order to explore the effect of extract (SNE) on skin wound healing in mice and its mechanism, hemostasis effect of SNE was measured, the mouse skin wound model was established by full-thickness excision. The morphological changes of the wound were observed after the treatment with SNE and the healing rate was measured. The changes of wound histology were observed by hematoxylin eosin (HE) staining, Masson staining and transmission electron microscope (TEM). The expression of cell factors and related proteins was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Results showed that the SNE possessed hemostatic function. SNE could obviously improve the healing rate of wound in mouse and shorten time of scab removal compared with the none-treatment (NT) group ( < 0.05).The pathological histology analysis results showed complete epidermal regeneration, with remarkable capillary and collagen fiber observed in the SNE group. The expression level of tumor necrosis factor-α (TNF -α), interleukin-1β (IL-1β) and transforming growth factor-β1 (TGF-β1) in SNE group was significantly lower than that of the NT group on 7 d ( < 0.05). Moreover, compared with the NT group, the gene expressions level of Smad7 was significantly increased and the level of type II TGF-β receptors (TGF-βRII), collagen I (COL1A1) and α-smooth muscle actin (α-SMA) were significantly reduced in the SNE group on 28 d ( < 0.05), but the difference was not statistically significant compared to Yunnanbaiyao group (PC group) ( > 0.05). These results indicated that SNE possessed obvious activity of accelerating wound healing and inhibiting scar formation, and its mechanism was closely related to hemostatic function, regulation of inflammatory factors, collagen deposition, collagen fiber remodeling and intervening TGF-β/Smads signal pathway. Therefore, SNE may have promising clinical applications in skin wound repair and scar inhibition.
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http://dx.doi.org/10.7507/1001-5515.201908008DOI Listing
June 2020

Effect of Oral Administration of Active Peptides of on the Repair of Skin Wounds.

Mar Drugs 2019 Dec 12;17(12). Epub 2019 Dec 12.

College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China.

Skin wound healing, especially chronic wound healing, is a common challenging clinical problem. It is urgent to broaden the sources of bioactive substances that can safely and efficiently promote skin wound healing. This study aimed to observe the effects of active peptides (APs) of the mantle of on wound healing. After physicochemical analysis of amino acids and mass spectrometry of APs, the effect of APs on promoting healing was studied through a whole cortex wound model on the back of mice for 18 consecutive days. The results showed that APs consisted of polypeptides with molecular weights in the range 302.17-2936.43 Da. The content of polypeptides containing 2-15 amino acids accounted for 73.87%, and the hydrophobic amino acids accounted for 56.51%. Results of in vitro experimentation showed that mice in APs-L group which were fed a low dose of APs (0.5 g/kg bw) had a shortened epithelialization time due to a shortening inflammatory period ( < 0.05). Mechanistically, this relied on its specific ability to promote the proliferation of CD31, FGF and EGF which accelerated the percentage of wound closure. Moreover, the APs-L group mice had enhanced collagen synthesis and increased type III collagen content in their wounds through a TGF-β/Smad signaling pathway ( > 0.05). Consequently, scar formation was inhibited and wound healing efficiency was significantly improved. These results show that the APs of promote dermal wound healing in mice and have tremendous potential for development and utilization in skin wound healing.
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http://dx.doi.org/10.3390/md17120697DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6950544PMC
December 2019

Evaluation of Small Molecular Polypeptides from the Mantle of on Promoting Skin Wound Healing in Mice.

Molecules 2019 Nov 21;24(23). Epub 2019 Nov 21.

College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China.

Skin wound healing, especially chronic wound healing, is a common challenging clinical problem. It is urgent to broaden the sources of bioactive substances that can safely and efficiently promote skin wound healing. This study aimed to observe the effects of small molecular peptides (SMPs) of the mantle of on wound healing. After physicochemical analysis of amino acids and mass spectrometry of SMPs, the effect of SMPs on promoting healing was studied through a whole cortex wound model on the back of mice for 18 consecutive days. The results showed that SMPs consisted of polypeptides with a molecular weight of 302.17-2936.43 Da. The content of polypeptides containing 2-15 amino acids accounted for 73.87%, and the hydrophobic amino acids accounted for 56.51%. Results of in vitro experimentation showed that SMPs possess a procoagulant effect, but no antibacterial activity. Results of in vivo experiments indicated that SMPs inhibit inflammatory response by secretion of anti-inflammatory factor IL-10 during the inflammatory phase; during the proliferative phase, SMPs promote the proliferation of fibroblasts and keratinocytes. The secretion of transforming growth factor-β1 and cyclin D1 accelerates the epithelialization and contraction of wounds. In the proliferative phase, SMPs effectively promote collagen deposition and partially inhibit superficial scar hyperplasia. These results show that SMPs promotes dermal wound healing in mice and have a tremendous potential for development and utilization in skin wound healing.
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http://dx.doi.org/10.3390/molecules24234231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6930615PMC
November 2019

Functionalization of Molecularly Imprinted Polymer Microspheres for the Highly Selective Removal of Contaminants from Aqueous Solutions and the Analysis of Food-Grade Fish Samples.

Polymers (Basel) 2018 Oct 11;10(10). Epub 2018 Oct 11.

College of Materials Science and Energy Engineering, Foshan University, Foshan 528000, China.

The proliferation of pollution in aquatic environments has become a growing concernand calls for the development of novel adsorbents capable of selectively removing notorious andrecalcitrant pollutants from these ecosystems. Herein, a general strategy was developed for thesynthesis and functionalization of molecularly imprinted polymer microspheres (MIPs) that couldbe optimized to possess a significant adsorption selectivity to an organic pollutant in aqueousmedia, in addition to a high adsorption capacity. Considering that the molecular imprinting alonewas far from satisfactory to produce a high-performance MIPs-based adsorbent, further structuralengineering and surface functionalization were performed in this study. Although the more carboxylgroups on the surfaces of the MIPs enhanced the adsorption rate and capacity toward an organicpollutant through electrostatic interactions, they did not strengthen the adsorption selectivity in aproportional manner. Through a systematic study, the optimized sample exhibiting both impressiveselectivity and capacity for the adsorption of the organic pollutant was found to possess a smallparticle size, a high specific surface area, a large total pore volume, and an appropriate amount ofsurface carboxyl groups. While the pseudo-second-order kinetic model was found to better describethe process of the adsorption onto the surface of MIPs as compared to the pseudo-first-order kineticmodel, neither Langmuir nor Freundlich isothermal model could be used to well fit the isothermaladsorption data. Increased temperature facilitated the adsorption of the organic pollutant onto theMIPs, as an endothermic process. Furthermore, the optimized MIPs were also successfully employedas a stationary phase for the fabrication of a molecularly imprinted solid phase extraction column,with which purchased food-grade fish samples were effectively examined.
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http://dx.doi.org/10.3390/polym10101130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6403773PMC
October 2018

Humidity-tolerant rate-dependent capillary viscous adhesion of bee-collected pollen fluids.

Nat Commun 2019 03 26;10(1):1379. Epub 2019 Mar 26.

School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.

We report a two-phase adhesive fluid recovered from pollen, which displays remarkable rate tunability and humidity stabilization at microscopic and macroscopic scales. These natural materials provide a previously-unknown model for bioinspired humidity-stable and dynamically-tunable adhesive materials. In particular, two immiscible liquid phases are identified in bioadhesive fluid extracted from dandelion pollen taken from honey bees: a sugary adhesive aqueous phase similar to bee nectar and an oily phase consistent with plant pollenkitt. Here we show that the aqueous phase exhibits a rate-dependent capillary adhesion attributed to hydrodynamic forces above a critical separation rate. However, the performance of this adhesive phase alone is very sensitive to humidity due to water loss or uptake. Interestingly, the oily phase contributes scarcely to the wet adhesion. Rather, it spreads over the aqueous phase and functions as a barrier to water vapor that tempers the effects of humidity changes and stabilizes the capillary adhesion.
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http://dx.doi.org/10.1038/s41467-019-09372-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6435648PMC
March 2019

Correlation between human leukocyte antigen-G expression and clinical parameters in oral squamous cell carcinoma.

Indian J Cancer 2018 Oct-Dec;55(4):340-343

Department of Stomatology, Taizhou Hospital, Wenzhou Medical University, Linhai 317000, China.

Background: Human leukocyte antigen-G (HLA-G) is a tumor-associated molecule, whose expression may help the cancer cells to escape the immune response.

Aims: The aim of this study was to evaluate the diagnostic value of HLA-G level in oral squamous cell carcinoma (OSCC).

Materials And Methods: A total of 52 patients who had definite pathological diagnosis and 20 cases of healthy controls were enrolled in this clinical trial. Immunohistochemisty (IHC) and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis were considered for HLA-G identification and multilevel validations. Statistical analysis was performed using SPSS and statistical significance was determined at P < 0.05.

Results: IHC results demonstrated that the expression of HLA-G in OSCC was strongly positive and the rate of positive expression was 55.77% (29/52), but the expression of HLA-G in healthy controls was negative (0/20). Furthermore, RT-PCR results showed that the positive expression rate of HLA-G messenger RNA was weak in healthy controls, but strong in OSCC. Besides, HLA-G expression in the tumors was significantly correlated with histological grade.

Conclusions: Our results suggested that HLA-G is associated with the prognosis of OSCC and may serve as a novel therapeutic target.
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http://dx.doi.org/10.4103/ijc.IJC_602_17DOI Listing
June 2019

Sustainable and long-time 'rejuvenation' of biomimetic water-repellent silica coating on polyester fabrics induced by rough mechanical abrasion.

J Colloid Interface Sci 2018 Apr 6;516:202-214. Epub 2018 Feb 6.

School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

The economical use of water-repellent coatings on polymeric materials in commercial and industrial applications is limited by their mechanical wear robustness and long-term durability. In this study, we demonstrate that polyethylene terephthalate (PET) fabric modified with inorganic, methyltrimethoxysilane (MTMS)-based coatings shows excellent resistance against various types of wear damage, thereby mimicking superhydrophobic biological materials. These features were facilitated by the rational design of coating processing that also enabled tunable hierarchical surface structure. A series of custom and standard testing protocols revealed that coating-to-substrate adhesion was remarkably high, as was the resistance to various mechanical abradents. The most intriguing characteristic observed during aging and abrasion cycles was the enhancement in non-wettability or 'rejuvenation' reflected by water droplet roll-off behavior, a characteristic of self-cleaning materials. Water-repellent properties of coated polyester were also enhanced by prolonged thermal annealing and were maintained after custom laundry. The developed technology offers opportunities to design low cost, durable and functional textiles for both indoor and outdoor applications.
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http://dx.doi.org/10.1016/j.jcis.2018.01.055DOI Listing
April 2018

Adhesion Enhancements and Surface-Enhanced Raman Scattering Activity of Ag and [email protected] Nanoparticle Decorated Ragweed Pollen Microparticle Sensor.

ACS Appl Mater Interfaces 2017 Jul 17;9(29):24804-24811. Epub 2017 Jul 17.

School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive, Atlanta, Georgia 30332, United States.

A simple solution processed layer-by-layer approach was used to immobilize metal nanoparticles (NPs) on the surface of ragweed pollen exine to obtain multifunctional particles with significant surface-enhanced Raman scattering (SERS), two-photon excited fluorescence, and enhanced adhesion properties. The rugged pollen exine was functionalized with an amine terminated silane and then treated with Ag or [email protected] NPs that were electrostatically attached to the exterior of the pollen by incubation in an NP solution of the appropriate pH. Nanoparticle agglomeration on the pollen gives rise to broadband near infrared (NIR) (785-1064 nm) plasmonic activity, and strong SERS signals from benzenedithiol deposited on NP-pollen composite particles were observed. In addition to SERS activity, the AgNP coating provides a twofold increase in the adhesive properties of the RW pollen exine on a silicon substrate, leading to a robust, adhesive, broadband NIR excitable SERS microparticle.
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http://dx.doi.org/10.1021/acsami.6b15664DOI Listing
July 2017

Comparative Transcriptomic Analysis of Vernalization- and Cytokinin-Induced Floral Transition in Dendrobium nobile.

Sci Rep 2017 03 31;7:45748. Epub 2017 Mar 31.

College of life sciences, South China Agricultural University, Guangzhou, 510642, China.

Vernalization is required for floral initiation in Dendrobium. Interestingly, those beneficial effects can also be achieved by exogenous cytokinin application in greenhouses. Thus, an as yet unknown crosstalk/interaction may exist between vernalization and cytokinin signaling pathways. In this study, we showed, by de novo transcriptome assembly using RNA-seq data from both vegetative and reproductive tissue samples, that some floral transition-related genes-DnVRN1, FT, SOC1, LFY and AP1-were differentially expressed in low-temperature-challenged (LT) or thidiazuron (TDZ)-treated plants, compared to those mock-treated (CK). Both LT and TDZ upregulated SOC1, LFY and AP1, while the upregulation of DnVRN1 and FT was only LT-induced. We further found that LT promoted the upregulation of some key cytokinin signaling regulators, including several cytokinin biosynthesis-related genes and type-B response regulator (RR)-encoding genes, and that both LT and TDZ triggered the significant upregulation of some marker genes in the gibberellin (GA) signaling pathway, indicating an important low temperature-cytokinin-GA axis in flowering. Our data thus have revealed a cytokinin-GA signal network underlying vernalization, providing a novel insight into further investigation of the molecular mechanism of floral initiation in Dendrobium.
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http://dx.doi.org/10.1038/srep45748DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5374638PMC
March 2017

Pressure sensitive microparticle adhesion through biomimicry of the pollen-stigma interaction.

Soft Matter 2016 Mar;12(11):2965-75

School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, USA.

Many soft biomimetic synthetic adhesives, optimized to support macroscopic masses (∼kg), have been inspired by geckos, insects and other animals. Far less work has investigated bioinspired adhesion that is tuned to micro- and nano-scale sizes and forces. However, such adhesive forces are extremely important in the adhesion of micro- and nanoparticles to surfaces, relevant to a wide range of industrial and biological systems. Pollens, whose adhesion is critical to plant reproduction, are an evolutionary-optimized system for biomimicry to engineer tunable adhesion between particles and micro-patterned soft matter surfaces. In addition, the adhesion of pollen particles is relevant to topics as varied as pollinator ecology, transport of allergens, and atmospheric phenomena. We report the first observation of structurally-derived pressure-sensitive adhesion of a microparticle by using the sunflower pollen and stigma surfaces as a model. This strong, pressure-sensitive adhesion results from interlocking between the pollen's conical spines and the stigma's receptive papillae. Inspired by this behavior, we fabricated synthetic polymeric patterned surfaces that mimic the stigma surface's receptivity to pollen. These soft mimics allow the magnitude of the pressure-sensitive response to be tuned by adjusting the size and spacing of surface features. These results provide an important new insight for soft material adhesion based on bio-inspired principles, namely that ornamented microparticles and micro-patterned surfaces can be designed with complementarity that enable a tunable, pressure-sensitive adhesion on the microparticle size and length scale.
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http://dx.doi.org/10.1039/c5sm02845kDOI Listing
March 2016

Effect of water absorption on pollen adhesion.

J Colloid Interface Sci 2015 Mar 4;442:133-9. Epub 2014 Dec 4.

School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, GA 30332-0100, United States. Electronic address:

Pollens possess a thin liquid coating, pollenkitt, which plays a major role in adhesion by forming capillary menisci at interfaces. Unfortunately, the influence of humidity on pollenkitt properties and capillary adhesion is unknown. Because humidity varies widely in the environment, the answers have important implications for better understanding plant reproduction, allergy and asthma, and pollen as atmospheric condensation nuclei. Here, pollenkitt-mediated adhesion of sunflower pollen to hydrophilic and hydrophobic surfaces was measured as a function of humidity. The results quantify for the first time the significant water absorption of pollenkitt and the resulting complex dependence of adhesion on humidity. On hydrophilic Si, adhesion increased with increasing RH for pollens with or without pollenkitt, up to 200nN at 70% RH. In contrast, on hydrophobic PS, adhesion of pollenkitt-free pollen is independent of RH. Surprisingly, when pollenkitt was present adhesion forces on hydrophobic PS first increased with RH up to a maximum value at 35% RH (∼160nN), and then decreased with further increases in RH. Independent measurement of pollenkitt properties is used with models of capillary adhesion to show that humidity-dependent changes in pollenkitt wetting and viscosity are responsible for this complex adhesion behavior.
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http://dx.doi.org/10.1016/j.jcis.2014.11.065DOI Listing
March 2015

Copper-organic/octamolybdates: structures, bandgap sizes, and photocatalytic activities.

Inorg Chem 2014 Apr 7;53(7):3464-70. Epub 2014 Mar 7.

Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.

The structures, optical bandgap sizes, and photocatalytic activities are described for three copper-octamolybdate hybrid solids prepared using hydrothermal methods, [Cu(pda)]4[β-Mo8O26] (I; pda = pyridazine), [Cu(en)2]2[γ-Mo8O26] (II; en = ethylenediamine), and [Cu(o-phen)2]2[α-Mo8O26] (III; o-phen = o-phenanthroline). The structure of I consists of a [Cu(pda)]4(4+) tetramer that bridges to neighboring [β-Mo8O26](4-) octamolybdate clusters to form two-dimensional layers that stack along the a axis. The previously reported structures of II and III are constructed from [Cu2(en)4Mo8O26] and [Cu2(o-phen)4Mo8O26] clusters. The optical bandgap sizes were measured by UV-vis diffuse reflectance techniques to be ∼1.8 eV for I, ∼3.1 eV for II, and ∼3.0 eV for III. Electronic structure calculations show that the smaller bandgap size of I originates primarily from an electronic transition between the valence and conduction band edges comprised of filled 3d(10) orbitals on Cu(I) and empty 4d(0) orbitals on Mo(VI). Both II and III contain Cu(II) and exhibit larger bandgap sizes. Accordingly, aqueous suspensions of I exhibit visible-light photocatalytic activity for the production of oxygen at a rate of ∼90 μmol O2 g(-1) h(-1) (10 mg samples; radiant power density of ∼1 W/cm(2)) and a turnover frequency per calculated surface [Mo8O26](4-) cluster of ∼36 h(-1). Under combined ultraviolet and visible-light irradiation, I also exhibits photocatalytic activity for hydrogen production in 20% aqueous methanol of ∼316 μmol H2 g(-1) h(-1). By contrast, II decomposed during the photocatalysis measurements. The molecular [Cu2(o-phen)4(α-Mo8O26)] clusters of III dissolve into the aqueous methanol solution under ultraviolet irradiation and exhibit homogeneous photocatalytic rates for hydrogen production of up to ∼8670 μmol H2·g(-1) h(-1) and a turnover frequency of 17 h(-1). The clusters of III can be precipitated out by evaporation and redispersed into solution with no apparent decrease in photocatalytic activity. During the photocatalysis measurements, the dissolution of the clusters in III is found to occur with the reduction of Cu(II) to Cu(I), followed by subsequent detachment from the octamolybdate cluster. The lower turnover frequency, but higher photocatalytic rate, of III arises from the net contribution of all dissolved [Cu2(o-phen)4(α-Mo8O26)] clusters, compared to only the surface clusters for the heterogeneous photocatalysis of I.
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http://dx.doi.org/10.1021/ic402910aDOI Listing
April 2014

Pollenkitt wetting mechanism enables species-specific tunable pollen adhesion.

Langmuir 2013 Mar 22;29(9):3012-23. Epub 2013 Feb 22.

School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, USA.

Plant pollens are microscopic particles exhibiting a remarkable breadth of complex solid surface features. In addition, many pollen grains are coated with a viscous liquid, "pollenkitt", thought to play important roles in pollen dispersion and adhesion. However, there exist no quantitative studies of the effects of solid surface features or pollenkitt on adhesion of pollen grains, and it remains unclear what role these features play in pollen adhesion and transport. We report AFM adhesion measurements of five pollen species with a series of test surfaces in which each pollen has a unique solid surface morphology and pollenkitt volume. The results indicate that the combination of surface morphology (size and shape of echinate or reticulate features) with the pollenkitt volume provides pollens with a remarkably tunable adhesion to surfaces. With pollenkitt removed, pollen grains had relatively low adhesion strengths that were independent of surface chemistry and scalable with the tip radius of the pollen's ornamentation features, according to the Hamaker model. With the pollenkitt intact, adhesion was up to 3-6 times higher than the dry grains and exhibited strong substrate dependence. The adhesion enhancing effect of pollenkitt was driven by the formation of pollenkitt capillary bridges and was surprisingly species-dependent, with echinate insect-pollinated species (dandelion and sunflower) showing significantly stronger adhesion and higher substrate dependence than wind-pollinated species (ragweed, poplar, and olive). The combination of high pollenkitt volume and large convex, spiny surface features in echinate entomophilous varieties appears to enhance the spreading area of the liquid pollenkitt relative to varieties of pollen with less pollenkitt volume and less pronounced surface features. Measurements of pollenkitt surface energy indicate that the adhesive strength of capillary bridges is primarily dependent on nonpolar van der Waals interactions, with some contribution from the Lewis basic component of surface energy.
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http://dx.doi.org/10.1021/la305144zDOI Listing
March 2013

Multivariate statistical analysis of Raman images of a pharmaceutical tablet.

Appl Spectrosc 2012 Mar;66(3):272-81

School of Electrical and Electronic Engineering, University of Manchester, UK.

This paper describes the application of principal component analysis (PCA) and independent component analysis (ICA) to identify the reference spectra of a pharmaceutical tablet's constituent compounds from Raman spectroscopic data. The analysis shows, first with a simulated data set and then with data collected from a pharmaceutical tablet, that both PCA and ICA are able to identify most of the features present in the reference spectra of the constituent compounds. However, the results suggest that the ICA method may be more appropriate when attempting to identify unknown reference spectra from a sample. The resulting PCA and ICA models are subsequently used to estimate the relative concentrations of the constituent compounds and to produce spatial distribution images of the analyzed tablet. These images provide a visual representation of the spatial distribution of the constituent compounds throughout the tablet. Images associated with the ICA scores are found to be more informative and not as affected by measurement noise as the PCA based score images. The paper concludes with a discussion of the future work that needs to be undertaken for ICA to gain wider acceptance in the applied spectroscopy community.
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http://dx.doi.org/10.1366/11-06238DOI Listing
March 2012

Ligand-based modification of the structures and optical properties of new silver(I)-rhenate(VII) oxide/organic hybrid solids.

Inorg Chem 2009 Dec;48(23):11265-76

Department of Chemistry, North Carolina State University, Raleigh North Carolina 27695-8204, USA.

A new series of silver(I)-rhenate(VII) hybrids was systematically prepared under hydrothermal conditions from eight different N-donor organic ligands (isonicotinate = inca, pyrazine-2-carboxylate = pzc, 1,2,4-triazole = tro, pyridazine = pda, 4,4'-bipyridine = bpy, 1,2-bis(4-pyridyl)-ethane = dpa, 2,3-bis(2-pyridyl)pyrazine = bpp, and tetra-2-pyridinylpyrazine = tpp), and their resulting structures and optical properties were investigated. The reactions targeted a 1:1 molar ratio of Ag/Re, and new hybrid solids were prepared with the compositions Ag(bpp)ReO(4) (1), Ag(tpp)ReO(4) x H(2)O (2), Ag(Hinca)(2)ReO(4) x H(2)O (3), Ag(tro)ReO(4) (4), Ag(pda)ReO(4) x 1/2 H(2)O (5), Ag(Hpzc)ReO(4) (6), Ag(2)(Hpzc)(pzc)(H(2)O)ReO(4) (7), Ag(bpy)ReO(4) (8), and Ag(dpa)(2)ReO(4) (9). Hybrid solids 1, 2, and 3 each exhibit low-dimensional structures, consisting of [Ag(2)(bpp)(4)](2+) and [Ag(2)(Hinca)(4)](2+) dimers in 1 and 3, respectively, and [Ag(tpp)](n)(n+) chains in 2. Hybrid solids 4 and 5 contain a [Ag(tro)](+) chain and a [Ag(3)(pda)(3)](3+) cyclic trimer, respectively, that are both ReO(4)-bridged into layered structures. Both 6 and 8 consist of ligand-pillared "AgReO(4)" layers, while 7 is a Re-deficient analogue of 6 that contains ligand-pillared [Ag(2)(H(2)O)ReO(4)](+) layers where H(2)O replaces the missing ReO(4)(-) anion. The hybrid networks of 8 and 9 are interpenetrating, owing to the length of the bpy and dpa ligands, and consist of bpy-pillared "AgReO(4)" layers and ReO(4)-filled [Ag(dpa)(2)](+) diamond-type networks that are 2-fold and 6-fold interpenetrating, respectively. Their optical properties and thermal stabilities were investigated using UV-vis transmittance, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The measured properties were analyzed with respect to the varying structural modifications. The Ag-ReO(4) network dimensionalities, Ag coordination environments, and the ligand lengths and geometries are found to play important roles in the absorption coefficients, bandgap sizes, and whether the structure collapses softly to give condensed AgReO(4), respectively.
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http://dx.doi.org/10.1021/ic901749rDOI Listing
December 2009

Ligand-mediated interconversion of multiply-interpenetrating frameworks in Cu(I)/Re(VII)-oxide hybrids.

Inorg Chem 2009 Sep;48(18):8940-6

Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.

Two new copper(I)-rhenate(VII) hybrid solids, Cu(bpy)ReO(4) (I) and Cu(bpy)(2)ReO(4).0.5H(2)O (II) (bpy = 4,4'-bipyridine), with 2-fold and 4-fold interpenetrating networks, respectively, were prepared from hydrothermal reactions, and their structures characterized by single-crystal X-ray diffraction [I, Pbca (No. 61), Z = 8, a = 10.8513(3) A, b = 12.9419(4) A, c = 15.6976(5) A; II, P1 (No. 2), Z = 2, a = 11.8190(4) A, b = 12.6741(4) A, c = 13.7585(5) A, alpha = 85.8653(13) degrees, beta = 81.6197(13) degrees, gamma = 84.0945(11) degrees]. The structure of I contains 6(3) nets of neutral CuReO(4) layers that are pillared via bpy ligands on the Cu sites {CuO(3)N(2)} to yield a 2-fold interpenetrating pillared-layered network. Conversely, the structure of II consists of a 4-fold interpenetrating diamond-type network with tetrahedral {CuN(4)} coordination nodes that are bridged by bpy ligands, with both H(2)O and ReO(4)(-) within the pores. A surprising reversible structural interconversion between these two interpenetrating structures is possible via the insertion and removal of a single bpy ligand and (1/2)H(2)O per copper atom. The structural interconversion is accompanied by a change in color from yellow to red for I and II, respectively. Measured UV-vis diffuse reflectance spectra exhibit a significant red-shift in the absorption edge of approximately 0.3 eV, with the optical bandgap size decreasing from approximately 2.5 eV to approximately 2.2 eV for I and II, respectively. X-ray photoelectron spectra and electronic structure calculations indicate that the valence band derived from the Cu 3d and N 2p orbitals in II are pushed higher in energy compared to those in I because of the coordination of the additional bpy ligand. There is a much smaller change in the energy of the conduction band that is derived from the Re 5d orbitals. These results demonstrate that the ligand-mediated structural transformations of (d(0)/d(10))-hybrid solids represent a new and convenient low-temperature approach to modulate their optical bandgap sizes toward the visible wavelengths for use with solar energy.
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September 2009

Synthesis and structures of a new series of silver-vanadate hybrid solids and their optical and photocatalytic properties.

Inorg Chem 2008 Sep 13;47(18):8044-52. Epub 2008 Aug 13.

Department of Chemistry, North Carolina State University,Raleigh, North Carolina 27695-8204, USA.

Three new silver-vanadate hybrid solids, [Ag(bpy)]4V4O12 x 2 H2O (I), [Ag(dpa)]4V4O12 x 4 H2O (II), and Ag4(pzc)2V2O6 (III) (bpy = 4,4'-bipyridine, dpa = 1,2-bis(4-pyridyl)-ethane, pzc = pyrazinecarboxylate), were synthesized by hydrothermal methods and characterized using single crystal X-ray diffraction (I, P2(1)/c, Z = 4, a = 11.375(2) A, b = 14.281(4) A, c = 13.598(3) A, beta = 91.46(1) degrees; II, P2(1)/c, Z = 8, a = 13.5748(3) A, b = 15.3372(4) A, c = 14.1854(3) A, beta = 114.1410(9) degrees; III, P1, Z = 2, a = 3.580(1) A, b = 11.839(4) A, c = 19.321(7) A, alpha = 89.110(7) degrees, beta = 87.719(9) degrees, gamma = 86.243(8) degrees), thermogravimetric analysis, and UV-vis diffuse reflectance. The structures of I and II are constructed from neutral {Ag4V4O12}n layers of clusters that are pillared via the coordination of organic ligands (bpy for I and dpa for II) to the Ag sites in each layer. Conversely, the structure of III is composed of a three-dimensional {Ag2(pzc)(+)}n coordination network with channels containing {VO3(-)}n chains. The lattice water molecules can be removed upon heating to > or = 180 degrees C for I (reversibly) and to > or = 120 degrees C for II (irreversibly). All three decompose with the removal of organic ligands at higher temperatures of > 200-300 degrees C. Their optical bandgap sizes were measured to be 2.77 eV for I, 2.95 eV for II, and 2.45 eV for III, which decrease most notably as a result of the band widening for the more extended vanadate structure in III. All three hybrid solids are photocatalytically active for the decomposition of methylene blue under UV light (lambda < 400 nm; 1.01, 0.64, and 2.65 mg L(-1) h(-1) for I, II, and III, respectively), while only III exhibits a high activity under visible-light irradiation (lambda > 400 nm; 1.20 mg L(-1) h(-1) ). These new hybrid solids are among the first reported to exhibit high photocatalytic activities under either ultraviolet or visible-light irradiation and have also been analyzed with respect to the effect of the different organic ligands on their atomic- and electronic-structures.
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September 2008

Copper(I)-rhenate hybrids: syntheses, structures, and optical properties.

Inorg Chem 2007 Feb 27;46(4):1283-90. Epub 2007 Jan 27.

Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.

The new copper(I) rhenates, CuReO4(pyz) (I) and Cu3ReO4(q6c)2 (II) (pyz = pyrazine; q6c = quinoline-6-carboxylate), were synthesized by hydrothermal methods at 140-150 degrees C, and their structures determined via single-crystal X-ray diffraction (I, P21/n, No. 14, Z = 4, a = 7.972(1) A, b = 11.928(2) A, c = 8.430(1) A, beta = 102.161(2) degrees ; II, P21, No. 4, Z = 2, a = 8.253(2) A, b = 6.841(2) A, c = 18.256(6) A, beta = 101.37(2) degrees ) and characterized by thermogravimetric analyses and UV-vis diffuse reflectance. The structure of I contains 'CuReO4' layers that are pillared through bridging pyrazine ligands via the Cu sites, while the structure of II is polar and contains chains of 'Cu2ReO4' that are condensed into layers by coordination to linear 'Cu(q6c)2' bridges between the chains. In contrast to air-sensitive CuReO4, both hybrid analogues are stable in air owing to a stabilization of the Cu1+ oxidation state by N-donating ligands, but decompose upon heating with the removal of the organic ligands, which for I yields crystalline CuReO4. UV-vis diffuse reflectance measurements and electronic structure calculations on all three copper perrhenates, I, II, and CuReO4, show that each exhibits an optical band gap of approximately 2.1-2.2 eV, with conduction and valence band levels that are primarily derived from the Re d0 and Cu d10 orbitals, respectively, and mixed with O p-orbital contributions. In contrast to the silver rhenates, which have relatively lower energy Ag d10 orbitals, the inclusion of the organic ligands into the structures has only a very minor effect ( approximately 0.1 eV) on the band gap size. The optical absorptions, in combination with the air-stable open-framework layered structures, illustrate that heterometallic Cu1+/Re7+ oxides can be promising candidates for investigating in visible-light photocatalytic reactions.
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February 2007
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