bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the interaction between gelatin and polyurethanes derived from fatty acids
Authors: González‐Paz R. J. , Lligadas G. , Ronda J. C. , Galià M. , Ferreira A. M. , Boccafoschi F. , Ciardelli G. , Cádiz V.
Published: September 2012

In this study, gelatin was blended to proprietary noncytotoxic polyurethanes (PU) derived from vegetable oils with different weight ratios, as material for the preparation of novel biomedical products. The PU/gelatin blends were characterized for their morphology through scanning electron microscopy. Mechanical and thermal properties, chemical interactions between components, degradation behavior, surface properties, cell adhesion, and bioactivity were investigated as a function of the protein content. Higher blend miscibility was observed for the amorphous PUs, derived from oleic acid. Properties of PU/gelatin films were strongly influenced by the concentration of gelatin in the films. Gelatin enhanced the hydrophilicity, bioactivity, and cell adhesion of PUs. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Surface chemistry of grafted expanded poly(tetrafluoroethylene) membranes modifies the in vitro proinflammatory response in macrophages
Authors: Chandler‐Temple Adrienne , Kingshott Peter , Wentrup‐Byrne Edeline , Cassady A. Ian , Grøndahl Lisbeth
Published: September 2012

A series of surface‐modified expanded poly(tetrafluoroethylene) membranes showed varied levels of in vitro macrophage proinflammatory response. Membranes containing a mixture of phosphate and hydroxyl groups (as determined by X‐ray photoelectron spectroscopy analysis) stimulate greater macrophage activation than samples containing a mixture of phosphate and carboxylic acid segments. The types of proteins that adsorbed irreversibly from serum onto the two samples with the highest and lowest cellular response were investigated using surface‐matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry. Distinct differences in the number and type of proteins that adsorbed were observed between these samples. A correlation was found between the main protein components adsorbed onto the surfaces and the resulting in vitro proinflammatory response. This study strongly supports the hypothesis that the cellular response is not controlled directly by surface properties but is mediated by specific protein adsorption events. This in turn highlights the importance of better understanding and controlling the properties of intelligent surface‐modified biomaterials. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Osteoblasts response to nylon 6,6 blended with single‐walled carbon nanohorn
Authors: Misra R.D.K. , Chaudhari P.M.
Published: September 2012

Bioactivity is an important aspect that can be appropriately used to tune the cellular interactions occurring at the biomaterial‐physiological interface. In this regard, we explore here the nano‐ or quantum‐size effects of a highly dispersible nanostructured carbon present in the void space between the polymers chains (Nylon 6,6) in modulating the cellular functions when osteoblasts are seeded on biocompatible substrates. The filling‐up of void space in polymer facilitates filopodia to access the extracellular matrix, enabling integrin receptors to bind to the artificial biomedical device, promoting cellular interactions. In this regard, the fundamental principles of materials processing and cellular biology were combined to elucidate the mechanism of cell‐substrate interactions and the molecular machinery controlling the cell response. This is accomplished by investigating cell attachment, proliferation, and morphology, including cytomorphometry evaluation and quantitative assessment of prominent proteins, actin, vinculin, and fibronectin that are sensitive to cell‐substrate interactions. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Nuclear and cellular alignment of primary corneal epithelial cells on topography
Authors: Raghunathan Vijay Krishna , McKee Clayton T. , Tocce Elizabeth J. , Nealey Paul F. , Russell Paul , Murphy Christopher J.
Published: September 2012

The basement membrane of the corneal epithelium presents biophysical cues in the form of topography and compliance that can modulate cytoskeletal dynamics, which, in turn, can result in altering cellular and nuclear morphology and alignment. In this study, the effect of topographic patterns of alternating ridges and grooves on nuclear and cellular shape and alignment was determined. Primary corneal epithelial cells were cultured on either planar or topographically patterned (400–4000 nm pitch) substrates. Alignment of individual cell body was correlated with respective nucleus for the analysis of orientation and elongation. A biphasic response in alignment was observed. Cell bodies preferentially aligned perpendicular to the 800 nm pitch; and with increasing pitch, cells increasingly aligned parallel to the substratum. Nuclear orientation largely followed this trend with the exception of those on 400 nm. On this biomimetic size scale, some nuclei oriented perpendicular to the topography while their cytoskeleton elements aligned parallel. Both nuclei and cell bodies were elongated on topography compared to those on flat surfaces. Our data demonstrate that nuclear orientation and shape are differentially altered by topographic features that are not mandated by alignment of the cell body. This novel finding suggests that nuanced differences in alignment of the nucleus versus the cell body exist and that these differences could have consequences on gene and protein regulation that ultimately regulate cell behaviors. A full understanding of these mechanisms could disclose novel pathways that would better inform evolving strategies in cell, stem cell, and tissue engineering as well as the design and fabrication of improved prosthetic devices. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
MesoBioNano explorer—A universal program for multiscale computer simulations of complex molecular structure and dynamics
Authors: Solov'yov Ilia A. , Yakubovich Alexander V. , Nikolaev Pavel V. , Volkovets Ilya , Solov'yov Andrey V.
Published: September 2012

We present a multipurpose computer code MesoBioNano Explorer (MBN Explorer). The package allows to model molecular systems of varied level of complexity. In particular, MBN Explorer is suited to compute system's energy, to optimize molecular structure as well as to consider the molecular and random walk dynamics. MBN Explorer allows to use a broad variety of interatomic potentials, to model different molecular systems, such as atomic clusters, fullerenes, nanotubes, polypeptides, proteins, DNA, composite systems, nanofractals, and so on. A distinct feature of the program, which makes it significantly different from the existing codes, is its universality and applicability to the description of a broad range of problems involving different molecular systems. Most of the existing codes are developed for particular classes of molecular systems and do not permit multiscale approach while MBN Explorer goes beyond these drawbacks. On demand, MBN Explorer allows to group particles in the system into rigid fragments, thereby significantly reducing the number of dynamical degrees of freedom. Despite the universality, the computational efficiency of MBN Explorer is comparable (and in some cases even higher) than the computational efficiency of other software packages, making MBN Explorer a possible alternative to the available codes. © 2012 Wiley Periodicals, Inc.
Minimally invasive ultrasound‐guided carpal tunnel release: A cadaver study
Authors: de la Fuente Javier , Miguel‐Perez Maria Isabel , Balius Ramon , Guerrero Valentin , Michaud Johann , Bong David
Published: September 2012

Background.

Carpal tunnel syndrome is a common condition frequently requiring surgical intervention. We describe a new minimally invasive surgical technique for carpal tunnel release utilizing ultrasound (US) visualization.

Methods.

The technique was performed on 20 fresh frozen cadaver specimens. A surgical metallic probe with a “U”‐shaped trough and upward curved distal tip was precisely positioned in the carpal tunnel with US guidance followed by division of the flexor retinaculum (FR) with a “V”‐shaped scalpel.

Results.

Complete division of the FR was confirmed by US. Dissection performed on the specimens confirmed complete release of FR and absence of neurovascular injury. The distance from the division of the FR to these structures, the “safety margins,” was measured.

Conclusions.

This new technique for carpal tunnel release appears to combine the safety and efficacy of open carpal tunnel surgery with the advantages of the minimally invasive techniques. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2013
Intima‐medial thickness homogeneity in the common carotid artery: Measurement method and preliminary clinical study
Authors: Cheng Xinyao , Zhou Yuan , Jin Yalei , Li Guokuan , Wang Hua , Song Enmin
Published: September 2012

Background.

To propose and test in a preliminary clinical study a novel method for calculating intima‐medial thickness (IMT) homogeneity (IMTH).

Methods.

IMT was measured off‐line on every horizontal pixel line along the far wall of the common carotid artery, with previously validated software. IMTH was assessed by the SD, coefficient of variation, and interval distribution of obtained IMT values. This method was applied to 129 individuals (age, 40–60 years), including 49 healthy control subjects, 44 subjects at high risk of atherosclerosis, and 36 subjects with known atherosclerosis. Differences with a p value <0.05 were considered statistically significant.

Results.

SD and coefficient of variation were higher in the high‐risk than in the control group, as well as in high‐risk and control subgroups with maximal IMT = 0.8 mm or mean IMT = 0.55–0.65 mm. There were 85.7, 62.8, and 36% of IMT values in the 0.4‐ to 0.6‐mm range and 0.89, 13.8, and 21.2% of IMT values in the 0.8‐ to 1.2‐mm range in the control, high‐risk, and atherosclerosis groups, respectively.

Conclusions.

IMTH is a promising approach for the assessment of atherosclerosis, in addition to conventional IMT measurement. Further clinical studies are needed to assess its clinical usefulness. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012
Morphology of the tongue dorsal surface of gilthead seabream (Sparus aurata)
Authors: Abbate F. , Guerrera M.C. , Montalbano G. , Ciriaco E. , Germanà A.
Published: September 2012

The gilthead seabream is a food fish, one of the most frequently used in aquaculture. In the species of commercial interest, feeding in captivity is very important and this process is strictly related to the morphological characteristics of the oral cavity. The aim of this study is, using the standard procedures for light and scanning electron microscopy, to analyze the morphology of the tongue dorsal surface to show if relationships are present between the tongue morphology and the nutritional habits and choices of this farmed species. The main characteristic of the gilthead seabream oral cavity floor is the presence of an apical pouch, with, probably, a protective role mainly for the apical, free part of the tongue. Three zones, like in other teleosts, an apex, a body and a root, can be clearly distinguished. In the pouch foliate‐like papillae were observed, while the whole tongue is characterized by the presence of two types of papillae, respectively with a fungiform and cylindroid aspect, both randomly distributed throughout the whole dorsal surface of the tongue. Scattered and numerous taste buds, with the typical pear‐onion shape, together with small and numerous taste pores are also present, distributed throughout the tongue surface. Our results demonstrate that in the gilthead seabream important mechanic and sensory roles are carried out by specific anatomical structures. Our anatomical data could give, together with further biochemical and physiological data, an important support with the aim of improving the nutrition of aquaculture species. Microsc. Res. Tech. © 2012 Wiley Periodicals, Inc.
Genotoxic and mutagenic effects of permethrin in mice: Micronuclei analysis in peripheral blood erythrocytes
Authors: Roma Gislaine Cristina , De Oliveira Patrícia Rosa , Araujo Andrea Mendez , Bechara Gervásio Henrique , Mathias Maria Izabel Camargo
Published: September 2012

Pyrethroids such as permethrin are synthetic compounds widely used in the agriculture of many countries to combat plagues and in domestic products, such as acaricides. Not so long ago these chemicals were characterized as non‐toxic for non‐target organisms; however, recent studies have showed that these compounds could present toxic potential for many organisms. In this sense, this study presents genotoxic and mutagenic potential of permethrin administered intraperitoneally in mice under artificial conditions by the use of micronucleus assay in the peripheral blood of these animals. The mice were divided into five groups: group I = negative control (distilled water), group II = positive control (cyclophosphamide), group III = 30% of permethrin LD50 (96 mg/kg), group IV = 50% of permethrin LD50 (160 mg/kg), and group V = 80% of permethrin LD50 (256 mg/kg). The peripheral blood was collected 24, 48, and 72 h after treatment. Results showed that all the tested permethrin dosages presented genotoxic and mutagenic effects 24 h after treatment, which would contradict the classification of this chemical product as moderately toxic, i.e., unable to cause damages to the cell DNA. Microsc. Res. Tech. © 2012 Wiley Periodicals, Inc.
Effects of extra‐embryonic provisioning on larval morphology and histogenesis in Boccardia proboscidea (Annelida, Spionidae)
Authors: Gibson Glenys , Carver David
Published: September 2012

Morphology is strongly correlated with trophic mode in marine invertebrate larvae. We asked if larval morphogenesis is influenced by adelphophagy, a trophic mode in which larvae are provisioned with additional yolk in the form of extra‐embryonic nurse eggs, instead of the more common increase in egg size. We used histology and scanning electron microscopy to analyze morphogenesis in Boccardia proboscidea, a polychaete that produces both small planktotrophic larvae and large adelphophagic larvae in a single egg capsule. Results indicate that both morphs are similar for histogenesis of ectodermal derivatives, and differ for the gut mucosa and coelom which show delayed differentiation in the adelphophagic morph. Heterochrony in gut and coelom development suggests that differentiation of these organ systems is decoupled from overall development, and that a trade‐off exists between maturation of these tissues and rapid growth. We also looked for potential barriers to adelphophagy in planktotrophic larvae that have nurse eggs available to them. These planktotrophic larvae appeared morphologically equipped for adelphophagy: the gut was differentiated at an early stage, and larvae had structures involved in nurse‐egg ingestion in the adelphophagic morph (e.g., oral cilia and ventral ciliated patches). Planktotrophic larvae were additionally capable of ingesting particles (Di‐I) while in the egg capsule. Lack of adelphophagy in planktotrophic larvae remains enigmatic but these results indicate that morphology alone does not account for the arrested development shown by these larvae. J. Morphol. 2013. © 2012 Wiley Periodicals, Inc.
Comparative morphology of porpoise (Cetacea: Phocoenidae) pterygoid sinuses: Phylogenetic and functional implications
Authors: Racicot Rachel A. , Berta Annalisa
Published: September 2012

High‐resolution X‐ray computed tomographic scans were used to examine pterygoid sinus morphology within extant porpoise species and one delphinid (Tursiops truncatus), in order to consider: 1) intraspecific and interspecific variation among the studied species; 2) the most parsimonious sequence of character acquisition; and 3) the potential functional roles of the preorbital lobes of the sinuses in sound reflection. Scans revealed that the pterygoid/palatine regions are mediolaterally broader in the earliest diverging phocoenid (Neophocaena phocaenoides) and Tursiops truncatus than the dorsoventrally elongated sinuses observed in other species. Rostrocaudal lengths of the sphenoidal regions of the sinuses in all individuals studied are proportionally similar, indicating conservatism in this region across species. The neonate Phocoena phocoena has shorter preorbital lobes than adults, but they are still proportionally longer than Neophocaena phocaenoides and Phocoena spinipinnis. The preorbital lobes broaden mediolaterally to varying degrees across species; in particular, Phocoenoides dalli has the largest dorsal and lateral expansion of this region. Assuming the highest pulse frequency produced by porpoises is 150 kHz, all regions of the preorbital lobes are thick enough to reflect the wavelengths produced. In addition, the neonate preorbital lobes are not as elongated as they are in adults, and the dorsal third of this region may not reflect sound to the same extent. This study reinforces the importance of using nondestructive methods to quantify variation in endocranial anatomy and the value of CT data for recovering phylogenetically useful information, as well as functional roles sinuses play in concert with the soft tissue head anatomy for biosonar. J. Morphol. 2013. © 2012 Wiley Periodicals, Inc.
Ultraviolet tip‐enhanced nanoscale Raman imaging
Authors: Park Kyoung‐Duck , Kim Yong Hwan , Park Jin‐Ho , Park Jung Su , Lee Hong Seok , Yim Sang‐Youp , Lee Young Hee , Jeong Mun Seok
Published: September 2012

We have constructed an ultraviolet (UV)‐apertureless near‐field scanning optical microscope‐Raman spectroscopy system by using an aluminum tip for the simultaneous measurement of topography and Raman scattering of nanomaterials with high spatial resolution. The topography, Rayleigh scattering image, and tip‐enhanced Raman scattering image of the carbon nanotube film showed that a spatial resolution of around 19 nm was achieved. This spatial resolution of UV‐Raman mapping image exceeds that of previous approaches, which have several hundred nanometers of spatial resolution. Copyright © 2012 John Wiley & Sons, Ltd.
Challenges in quantitative analyses for volatile organic compounds bound to lipocalins
Authors: Kwak Jae
Published: September 2012

In this communication, I describe the challenges in quantitative analyses for volatile organic compounds in mouse urine, which are primarily caused by the presence of the major urinary proteins, a lipocalin subfamily, that sequester volatile ligands. The analyses of volatile compounds in mouse urine have been performed since the late 1970s. However, none of them considered the binding interactions of the quantified compounds with the urinary proteins. Some volatile ligands are tightly bound to the proteins and may not be extracted completely by organic solvents. The amounts of volatile ligands measured by external standard calibration represent those of the unbound ligands in the headspace, not the total amounts in urine. Addition of internal standards displaces ligands bound to the proteins, resulting in a completely different volatile profile. Normalization of volatile compounds using relative peak area (or height) ratios may not be used in the conditions where displacement of ligands bound to the proteins occurs. Because of the unique chemical properties of mouse urine, I have not been able to find a good quantification method for the volatile compounds released from mouse urine. I hope that the identification of these issues will stimulate others to come up with novel approaches.
Factors that affect deceased donor liver transplantation rates in the United States in addition to the model for end-stage liver disease score
Authors: Sharma Pratima , Schaubel Douglas E. , Messersmith Emily E. , Guidinger Mary K. , Merion Robert M.
Published: September 2012

Under an ideal implementation of Model for End-Stage Liver Disease (MELD)–based liver allocation, the only factors that would predict deceased donor liver transplantation (DDLT) rates would be the MELD score, blood type, and donation service area (DSA). We aimed to determine whether additional factors are associated with DDLT rates in actual practice. Data from the Scientific Registry of Transplant Recipients for all adult candidates wait-listed between March 1, 2002 and December 31, 2008 (n = 57,503) were analyzed. Status 1 candidates were excluded. Cox regression was used to model covariate-adjusted DDLT rates, which were stratified by the DSA, blood type, liver-intestine policy, and allocation MELD score. Inactive time on the wait list was not modeled, so the computed DDLT hazard ratios (HRs) were interpreted as active wait-list candidates. Many factors, including the candidate's age, sex, diagnosis, hospitalization status, and height, prior DDLT, and combined listing for liver-kidney or liver-intestine transplantation, were significantly associated with DDLT rates. Factors associated with significantly lower covariate-adjusted DDLT rates were a higher serum creatinine level (HR = 0.92, P < 0.001), a higher bilirubin level (HR = 0.99, P = 0.001), and the receipt of dialysis (HR = 0.83, P < 0.001). Mild ascites (HR = 1.15, P < 0.001) and hepatic encephalopathy (grade 1 or 2, HR = 1.05, P = 0.02; grade 3 or 4, HR = 1.10, P = 0.01) were associated with significantly higher adjusted DDLT rates. In conclusion, adjusted DDLT rates for actively listed candidates are affected by many factors aside from those integral to the allocation system; these factors include the components of the MELD score itself as well as candidate factors that were considered but were deliberately omitted from the MELD score in order to keep it objective. These results raise the question whether additional candidate characteristics should be explicitly incorporated into the prioritization of wait-list candidates because such factors are already systematically affecting DDLT rates under the current allocation system. Liver Transpl, 2012. © 2012 AASLD.
Increased pulse wave velocity and carotid intima–media thickness in patients with carpal tunnel syndrome
Authors: Emre Durakoğlugil Murtaza , Çiçek Yüksel , Altan Kocaman Sinan , Sabri Balik Mehmet , Kirbaş Serkan , Çetin Mustafa , Erdoğan Turan , Çanga Aytun
Published: September 2012

Introduction: Carpal tunnel syndrome (CTS) is associated with cardiovascular risk factors. The aim of our study was to determine whether carotid intima–media thickness (CIMT) and carotid–femoral pulse wave velocity (cf‐PWV), as surrogates of cardiovascular disease and arterial stiffness, are increased in patients with carpal tunnel syndrome. Methods: Forty patients with CTS and 40 gender‐ and age‐matched controls underwent cf‐PWV assessment, CIMT measurement, and nerve conduction study. Results: CIMT and cf‐PWV were increased significantly in patients with CTS. They correlated positively with median sensory and motor nerve distal latency. Whereas both CIMT and PWV related to CTS, only CIMT independently predicted CTS. Conclusions: There is both increased pulse wave velocity and CIMT and a positive correlation between these parameters and median nerve sensory distal latency in patients with CTS. CTS appears to be associated with arterial stiffness and atherosclerotic burden, but the underlying mechanisms require further study. Muscle Nerve 47: 872–877, 2013
Finite element method for two‐dimensional time‐fractional tricomi‐type equations
Authors: Zhang Xindong , Huang Pengzhan , Feng Xinlong , Wei Leilei
Published: September 2012

In this article, we consider the finite element method (FEM) for two‐dimensional linear time‐fractional Tricomi‐type equations, which is obtained from the standard two‐dimensional linear Tricomi‐type equation by replacing the first‐order time derivative with a fractional derivative (of order α, with 1 <α< 2 ). The method is based on finite element method for space and finite difference method for time. We prove that the method is unconditionally stable, and the error estimate is presented. The comparison of the FEM results with the exact solutions is made, and numerical experiments reveal that the FEM is very effective. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2013
A BGK‐penalization‐based asymptotic‐preserving scheme for the multispecies Boltzmann equation
Authors: Jin Shi , Li Qin
Published: September 2012

An asymptotic‐preserving (AP) scheme is efficient in solving multiscale problems where kinetic and hydrodynamic regimes coexist. In this article, we extend the BGK‐penalization‐based AP scheme, originally introduced by Filbet and Jin for the single species Boltzmann equation (Filbet and Jin, J Comput Phys 229 (2010) 7625–7648), to its multispecies counterpart. For the multispecies Boltzmann equation, the new difficulties arise due to: (1) the breaking down of the conservation laws for each species and (2) different convergence rates to equilibria for different species in disparate masses systems. To resolve these issues, we find a suitable penalty function—the local Maxwellian that is based on the mean velocity and mean temperature and justify various asymptotic properties of this method. This AP scheme does not contain any nonlinear nonlocal implicit solver, yet it can capture the fluid dynamic limit with time step and mesh size independent of the Knudsen number. Numerical examples demonstrate the correct asymptotic‐behavior of the scheme. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2013
Silane coupling agent modification on interlaminar shear strength of carbon fiber/epoxy/nano‐CaCo3 composites
Authors: He Hongwei , Li Kaixi
Published: September 2012

Four different types of composites were prepared based on unmodified and modified epoxy matrices: (A) unmodified epoxy/carbon fiber composites, (B) modified epoxy/carbon fiber composites by silane coupling agent/nano‐CaCO3 master batch, (C) modified epoxy/carbon fiber composites by nano‐CaCO3 particles directly, and (D) modified epoxy/carbon fiber composites by nano‐CaCO3 particles and silane coupling agent together. The interlaminar shear strength (ILSS) of the carbon fiber‐reinforced composites was investigated. The results show that the silane coupling agent/nano‐CaCO3 master batch can increase the ILSS to the highest degree. Nevertheless, Sample D, i.e., modified by nano‐CaCO3 particles and silane coupling agent together, even presents a decrease of the ILSS. The integration effect of silane coupling agent/nano‐CaCO3 master batch was concluded. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Proteomic studies highlight outer‐membrane proteins related to biofilm development in the marine bacterium Pseudoalteromonas sp. D41
Authors: Ritter Andrés , Com Emmanuelle , Bazire Alexis , Goncalves Marina Dos Santos , Delage Ludovic , Pennec Gaël Le , Pineau Charles , Dreanno Catherine , Compère Chantal , Dufour Alain
Published: September 2012

Bacterial biofilm development is conditioned by complex processes involving bacterial attachment to surfaces, growth, mobility, and exoproduct production. The marine bacterium Pseudoalteromonas sp. strain D41 is able to attach strongly onto a wide variety of substrates, which promotes subsequent biofilm development. Study of the outer‐membrane and total soluble proteomes showed ten spots with significant intensity variations when this bacterium was grown in biofilm compared to planktonic cultures. MS/MS de novo sequencing analysis allowed the identification of four outer‐membrane proteins of particular interest since they were strongly induced in biofilms. These proteins are homologous to a TonB‐dependent receptor (TBDR), to the OmpW and OmpA porins, and to a type IV pilus biogenesis protein (PilF). Gene expression assays by quantitative RT‐PCR showed that the four corresponding genes were upregulated during biofilm development on hydrophobic and hydrophilic surfaces. The Pseudomonas aeruginosa mutants unable to produce any of the OmpW, OmpA, and PilF homologues yielded biofilms with lower biovolumes and altered architectures, confirming the involvement of these proteins in the biofilm formation process. Our results indicate that Pseudoalteromonas sp. D41 shares biofilm formation mechanisms with human pathogenic bacteria, but also relies on TBDR, which might be more specific to the marine environment.
MS‐based ligand binding assays with speed, sensitivity, and specificity
Authors: Roth Michael J. , Kim Jaekuk , Maresh Erica M. , Plymire Daniel A. , Corbett John R. , Zhang Junmei , Patrie Steven M.
Published: September 2012

Immunoassays are widely used in biochemical/clinical laboratories owing to their simplicity, speed, and sensitivity. We combined self‐assembled monolayer‐based immunoassays with MALDI‐TOF MS to show that high‐fidelity surface preparations with a novel matrix deposition/crystallization technique permits quantitative analysis of monolayer‐bound antigens at picomolar detection limits. Calibration curves for intact proteins are possible over a broad concentration range and improved specificity of MS‐immunoassays is highlighted by simultaneous label‐free quantitation of ligand‐bound protein complexes.
Metabolic and proteomic adaptation of Lactobacillus rhamnosus strains during growth under cheese‐like environmental conditions compared to de Man, Rogosa, and Sharpe medium
Authors: Bove Claudio Giorgio , Angelis Maria De , Gatti Monica , Calasso Maria , Neviani Erasmo , Gobbetti Marco
Published: September 2012

The aim of this study was to demonstrate the metabolic and proteomic adaptation of Lactobacillus rhamnosus strains, which were isolated at different stages of Parmigiano Reggiano cheese ripening. Compared to de Man, Rogosa, and Sharpe (MRS) broth, cultivation under cheese‐like conditions (cheese broth, CB) increased the number of free amino acids used as carbon sources. Compared with growth on MRS or pasteurized and microfiltrated milk, all strains cultivated in CB showed a low synthesis of d,l‐lactic acid and elevated levels of acetic acid. The proteomic maps of the five representative strains, showing different metabolic traits, were comparatively determined after growth on MRS and CB media. The amount of intracellular and cell‐associated proteins was affected by culture conditions and diversity between strains, depending on their time of isolation. Protein spots showing decreased (62 spots) or increased (59 spot) amounts during growth on CB were identified using MALDI‐TOF‐MS/MS or LC‐nano‐ESI‐MS/MS. Compared with cultivation on MRS broth, the L. rhamnosus strains cultivated under cheese‐like conditions had modified amounts of some proteins responsible for protein biosynthesis, nucleotide, and carbohydrate metabolisms, the glycolysis pathway, proteolytic activity, cell wall, and exopolysaccharide biosynthesis, cell regulation, amino acid, and citrate metabolism, oxidation/reduction processes, and stress responses.
Effect of side‐chain length on the electrospinning of perfluorosulfonic acid ionomers
Authors: Subianto Surya , Cavaliere Sara , Jones Deborah J. , Rozière Jacques
Published: September 2012

The effect of the side‐chain length (short side chain and long side chain, SSC and LSC, respectively) of perfluorosulfonic acid (PFSA) ionomers on the properties of nanofibers obtained by electrospinning ionomer dispersions in high dielectric constant liquids has been investigated with a view to obtaining electrospun webs as components of fuel cell membranes. Ranges of experimental conditions for electrospinning LSC and SSC PFSAs have been explored, with a scoping of solvents, carrier polymer and PFSA ionomer concentrations, and carrier polymer molecular weight. Under optimal conditions, the electrospun mats derived from SSC and from LSC PFSA show distinct fiber dimensions that arise from the different chain lengths of the respective ionomers. Enhanced interchain interactions in SSC PFSA with low equivalent weight compared to LSC PFSA result in a considerably lower average fiber diameter and a markedly narrower fiber size distribution. The proton conductivity of nanofiber mats of SSC and LSC PFSA with equivalent weights of 830 and 900 g mol−1, respectively, are 102 and 58 mS cm−1 at 80°C and 95% relative humidity. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Synthesis and polymerization kinetics of acrylamide phosphonic acids and esters as new dentine adhesives
Authors: Besse V. , Le Pluart L. , Cook W. D. , Pham T.‐N. , Madec P.‐J.
Published: September 2012

In restorative dentistry, acrylamide monomers bearing phosphonic acid moieties have proved to be useful species for the formulation of dental self‐etch adhesives since they provide enhanced adhesion to hydroxyapatite and are not subject to hydrolysis, thus potentially improving their adhesive durability. Previous studies have demonstrated that phosphonic acid acrylamides increase the rate of photopolymerization of diacrylamide monomers. To understand whether this rate acceleration is specific to the acrylamide function of the monomer, or due to the phosphonic acid group per se, or is applicable only with a crosslinking reaction, we have synthesized several acrylamide and methacrylate monomers bearing phosphonic acid or phosphonate moieties and studied their photopolymerization kinetics. The acrylamide phosphonic acid was found to accelerate the polymerization rate but similar monomers bearing a phosphonate ester group had a much smaller effect. A similar accelerating effect was observed when the phosphonic acid‐based monomers were copolymerized with a monofunctional acrylamide monomer, excluding the possibility that the rate acceleration might be related to the crosslinking process. This rate effect is also observed when a nonpolymerizable organic phosphonic acid is present in the polymerizing medium. We suggest that the increase of the medium polarity is responsible for this rate enhancement effect. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
New hyperbranched second‐order nonlinear optical poly(arylene‐ethynylene)s containing pentafluoroaromatic rings as isolation group: Facile synthesis and enhanced optical nonlinearity through Ar‐ArF self‐assembly effect
Authors: Wu Wenbo , Zhu Zhichao , Qiu Guofu , Ye Cheng , Qin Jingui , Li Zhen
Published: September 2012

In this article, a facile route was designed to prepare four new hyperbranched poly(arylene‐ethynylene)s containing azo‐chromophore moieties through one‐pot “A2+B3” approach via simple Sonogashira coupling reaction. The polymers were all soluble in organic solvents and demonstrated good nonlinear optical (NLO) properties, because of the three‐dimensional spatial isolation effect of these hyperbranched polymers. Due to the different B3‐type comonomer, the self‐assembly effect of pentafluoroaromatic in the interior of these polymers were different, leading to the different trends of the NLO activities. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of graft polymers with poly(isoprene) as main chain by living anionic polymerization mechanism
Authors: Tang Tingting , Huang Jian , Huang Bing , Huang Junlian , Wang Guowei
Published: September 2012

The graft polymers [poly(isoprene)‐graft‐poly(styrene)] (PI‐g‐PS), [poly(isoprene)‐graft‐poly(isoprene)] (PI‐g‐PI), [poly(isoprene)‐graft‐(poly(isoprene)‐block‐poly(styrene))] PI‐g‐(PI‐b‐PS), and [poly(isoprene)‐graft‐(poly(styrene)‐block‐poly(isoprene))] PI‐g‐(PS‐b‐PI) with PI as main chain were synthesized through living anionic polymerization (LAP) mechanism and the efficient coupling reaction. First, the PI was synthesized by LAP mechanism and epoxidized in H2O2/HCOOH system for epoxidized PI (EPI). Then, the graft polymers with controlled molecular weight of main chain and side chains, and grafting ratios were obtained by coupling reaction between PI−Li+, PS−Li+, PS‐b‐PI−Li+, or PI‐b‐PS−Li+ macroanions and the epoxide on EPI. The target polymers and all intermediates were well characterized by SEC,1H NMR, as well as their thermal properties were also evaluated by DSC. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Insights into poly(3‐hexylthiophene)‐b‐poly(ethylene oxide) block copolymer: Synthesis and solvent‐induced structure formation in thin films
Authors: Yang Hui , Xia Hao , Wang Guowei , Peng Juan , Qiu Feng
Published: September 2012

We report the synthesis, characterization, and solvent‐induced structure formation in thin films of an amphiphilic rod‐coil conjugated block copolymer, poly(3‐hexylthiophene)‐b‐poly(ethylene oxide). The diblock copolymers were prepared by a facile click reaction and their characterizations as well as thermal, crystalline, optical properties, and self‐assembly behavior have been investigated in detail. A series of morphologies including two‐phase separated nanostructure, nanofibrils, and their mixed morphology could be obtained depending on the selectivity of solvents to different blocks. Structural analyses demonstrate there is a subtle balance between microphase separation of copolymer and the π‐π stacking of the conjugated P3HT and such balance can be controlled by changing the solvents of different selectivity in solution and the length of P3HT block. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
The study of organic semiconductor/ferromagnet interfaces in organic spintronics: A short review of recent progress
Authors: Zhan Yiqiang , Fahlman Mats
Published: September 2012

An overview is given on recent results in organic spintronic research. In particular, so‐called spinterfaces, spin‐injecting interfaces involving organic semiconductor (OSC) molecules and ferromagnetic metals, are discussed. The interfaces are classified in different categories depending on the type and strength of interface interaction and the relevant physics concerning energy level alignment and spin polarization of interface states are explained. Examples are given on characterization of both interface energetics and spin‐related properties obtained from a wide variety of experimental techniques, highlighting the different ways contacting can modify the electronic and magnetic properties of the OSC molecules and the ferromagnetic metals at the resulting spinterfaces. Finally, models for spin injection at spinterfaces are presented and discussed, followed by some speculations on consequences for device design and performance. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Atomic mobility in strained glassy polymers: The role of fold catastrophes on the potential energy surface
Authors: Chung Yongchul G. , Lacks Daniel J.
Published: September 2012

Deformation is known to enhance the atomic mobility in disordered systems such as polymer materials. To elucidate the origin of this phenomenon, we carry out two types of simulations: molecular dynamics (MD) simulations, which determine the atomic trajectories at finite temperature, and quasi‐static simulations, which determine the atomic trajectories in the limit of zero temperature (and in the limit of zero shear rate). The quasi‐static simulations show discontinuous changes in properties, such as system energy and atomic mobility. We use a normal mode analysis to show that these discontinuous changes arise from fold catastrophes of the potential energy landscape, in which energy minima flatten out and the heights of energy barriers decrease to zero; this was demonstrated by normal mode frequencies following a power law with an exponent of 0.5 as the discontinuous change is approached. After the fold catastrophe, the system relaxes to a different energy minimum, giving rise to atomic displacements. These fold catastrophes are the only mechanism for diffusive atomic displacements in the quasi‐static simulations, where there is no thermal energy. We compared the mean‐squared displacements as a function of strain from the quasi‐static simulations to those from MD simulations (which do include thermal effects)—the similarity of the values of the mean‐squared displacements in these two types of simulations demonstrates that the fold catastrophes underlie the enhanced dynamics in strained polymer systems even at finite temperature. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Synthesis, solid‐state, and charge‐transport properties of conjugated polythiophene‐S,S‐dioxides
Authors: Cochran Justin E. , Amir Elizabeth , Sivanandan Kulandaivelu , Ku Sung‐Yu , Seo Jung Hwa , Collins Brian A. , Tumbleston John R. , Toney Michael F. , Ade Harald , Hawker Craig J. , Chabinyc Michael L.
Published: September 2012

An alkylated semiconducting polymer comprising alternating bithiophene‐[all]‐S,S‐dioxide and aromatic monothiophene units in the polymer backbone was synthesized with the intent of modifying the energy gap and lowest unoccupied molecular orbital for use as a stable n‐type semiconductor. Films spun from this semiconducting polymer were characterized utilizing X‐ray scattering, near edge X‐ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy, and thin‐film field effect transistors to determine how oxidation of the thiophene ring systems impacts the structural and electronic properties of the polymer. The thiophene‐S,S‐dioxide polymers have lower optical and electrical band gaps than corresponding thiophene polymers. X‐ray scattering results indicate that the polymers are well ordered with the π–π stacking distances increased by 0.4 Å relative to analogous thiophene polymers. The electrical stability of these polymers is poor in transistors with a drop in the field effect mobility by approximately one order of magnitude upon addition of just 5% of the thiophene‐S,S‐dioxide unit in a copolymer with thiophene. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013
Kinetic Monte Carlo simulation of the epitaxial growth of Si(100)
Authors: Günther Vivien , Mauß Fabian , Klauer Christian , Schlawitschek Christiane
Published: September 2012

3D Kinetic Monte Carlo (KMC) simulations have been carried out on the epitaxial growth of the silicon (100)2×1 surface as a function of surface temperature (570‐870 °C). The KMC model explicitly takes into account the anisotropy of the silicon (100)2×1 surface and the interaction of neighboring sites as a reaction event at a given surface site not only depends on the chemical nature of the site itself but also on steric factors and the local environment. Thus the model includes data about the local structure of the surface, the nature of the surface adatoms and their neighbors, the kinetic reaction parameters, and the incident precursor atoms. Reaction probabilities are calculated with the Arrhenius equation, kinetic parameters are taken from experimental and calculated data from the literature. First estimations are given for missing values. Silane is assumed to be the only gas‐phase reactant on the surface, coupling with the gas phase is carried out by silane partial pressure. For the first time a really complex algorithm comprehending 12 different surface sites and more than 100 reactions such as silane adsorption, SiHx decomposition and diffusion of adsorbed species is presented. The model provides a good fit to experimental observations and theoretical knowledge. Experimental data of growth rate and hydrogen coverage can be reproduced (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Joint pricing and openness decisions in software markets with reinforcing loops
Authors: Rahmandad Hazhir , Sibdari Soheil
Published: September 2012

In software markets, pricing and openness interact to determine profitability through the direct effect of openness on feasible prices and costs, and their impact on different reinforcing feedback loops such as network effects. We develop a simulation model of the inner workings of a software firm, product life cycle and market aggregation, and analyze their interactions in a competitive market. The reinforcing loops increase the value of early market lead and put pressure on the competing firms to seek such advantage. The competitive equilibrium under strong reinforcing loops calls for highly open software products with early discounts that significantly compromise the profitability of the players. Proprietary platforms and higher prices are favored when those mechanisms are weak. We discuss the implications of this analysis for the dynamics of different competitive markets as well as the contributions to the system dynamics literature in analyzing Nash equilibrium of differential games. Copyright © 2012 System Dynamics Society.
Progesterone‐enhanced sperm hyperactivation through IP3–PKC and PKA signals
Authors: Fujinoki Masakatsu
Published: September 2012

Propose

The present study examined whether regulation of progesterone‐enhanced hyperactivation of spermatozoa is associated with the production of inositol 1,4,5‐trisphosphate (IP3) and diacylglycerol (DAG) by phospholipase C (PLC) and cyclic adenosine monophosphate (cAMP) by adenylate cyclase (AC), as well as activation of protein kinase C (PKC) and protein kinase A (PKA).

Methods

Hamster spermatozoa were hyperactivated by incubation for 4 h in modified Tyrode's albumin lactate pyruvate (mTALP) medium. In order to examine the effects of IP3 receptor (IP3R), PKC and PKA on progesterone‐enhanced hyperactivation, their inhibitors (xestospongin C, bisindolylmaleimide 1 and H‐89) were used.

Results

Progesterone‐enhanced hyperactivation was significantly suppressed by the inhibitors of IP3R, PKC and PKA.

Conclusions

The results suggest that progesterone‐enhanced sperm hyperactivation occurs through two signal pathways. One is an intracellular Ca2+ signal through production of IP3 and DAG by PLC, binding of IP3 to IP3R and activation of PKC by DAG and Ca2+. The other is a cAMP–PKA signal through production of cAMP by AC and activation of PKA by cAMP.
Cytoprotective effect of the small GTPase RhoB expressed upon treatment of fibroblasts with the Ras‐glucosylating Clostridium sordellii lethal toxin
Authors: Huelsenbeck Johannes , May Martin , Schulz Florian , Schelle Ilona , Ronkina Natalia , Hohenegger Martin , Fritz Gerhard , Just Ingo , Gerhard Ralf , Genth Harald
Published: September 2012

Mono‐glucosylation of (H/K/N)Ras by Clostridium sordellii lethal toxin (TcsL) blocks critical survival signaling pathways, resulting in apoptosis. In this study, TcsL and K‐Ras knock‐down by siRNA are presented to result in expression of the cell death‐regulating small GTPase RhoB. TcsL‐induced RhoB expression is based on transcriptional activation involving p38alpha MAP kinase. Newly synthesized RhoB protein is rapidly degraded in a proteasome‐ and a caspase‐dependent manner, providing first evidence for caspase‐dependent degradation of a Rho family protein. Although often characterised as a pro‐apoptotic protein, RhoB suppresses caspase‐3 activation in TcsL‐treated fibroblasts. The finding on the cytoprotective activity of RhoB in TcsL‐treated cells re‐enforces the concept that RhoB exhibits cytoprotective rather than pro‐apoptotic activity in a cellular background of inactive Ras.
Glycine decarboxylase controls photosynthesis and plant growth
Authors: Timm Stefan , Florian Alexandra , Arrivault Stephanie , Stitt Mark , Fernie Alisdair R. , Bauwe Hermann
Published: September 2012

Photorespiration makes oxygenic photosynthesis possible by scavenging 2‐phosphoglycolate. Hence, compromising photorespiration impairs photosynthesis. We examined whether facilitating photorespiratory carbon flow in turn accelerates photosynthesis and found that overexpression of the H‐protein of glycine decarboxylase indeed considerably enhanced net‐photosynthesis and growth of Arabidopsis thaliana. At the molecular level, lower glycine levels confirmed elevated GDC activity in vivo, and lower levels of the CO2 acceptor ribulose 1,5‐bisphosphate indicated higher drain from CO2 fixation. Thus, the photorespiratory enzyme glycine decarboxylase appears as an important feed‐back signaller that contributes to the control of the Calvin–Benson cycle and hence carbon flow through both photosynthesis and photorespiration.