bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐intensity laser irradiation at 660 nm stimulates cytochrome c oxidase in stressed fibroblast cells
Authors: Houreld Nicolette N. , Masha Roland T. , Abrahamse Heidi 
Published: April 2012

AbstractBackground and ObjectiveLow‐intensity laser irradiation (LILI) has been used to modulate a variety of biological processes, including diabetic wound healing. The mechanism of action is thought to exist primarily with the mitochondria. This study aimed to determine the effect of irradiation on normal, diabetic, and ischemic mitochondrial electron transport chain (ETC) complexes.Materials and MethodsNormal, diabetic and ischemic human skin fibroblast mitochondria were irradiated in vitro at a wavelength of 660 nm and a fluence of either 5 or 15 J/cm2. Non‐irradiated mitochondria served as controls. Enzyme activities of mitochondrial complexes I, II, III, and IV were determined immediately post‐irradiation. Normal, diabetic, and ischemic cells were irradiated and adenosine triphosphate (ATP) and active mitochondria were determined by luminescence and fluorescent microscopy, respectively.ResultsIrradiated diabetic mitochondria at a fluence of 15 J/cm2 showed a significant decrease in complex III activity (P < 0.05). Normal (P < 0.01) and diabetic (P < 0.05) mitochondria irradiated at either 5 or 15 J/cm2 showed a significant increase in complex IV activity. ATP results showed a significant increase in irradiated normal cells (5 J/cm2; P < 0.05) and diabetic cells (15 J/cm2; P < 0.01). There was a higher accumulation of active mitochondria in irradiated cells than non‐irradiated cells.ConclusionIrradiation at 660 nm has the ability to influence mitochondrial enzyme activity, in particular cytochrome c oxidase. This leads to increased mitochondrial activity and ATP synthesis. Lasers Surg. Med. 44: 429–434, 2012. © 2012 Wiley Periodicals, Inc.
Quantification of venous vessel size in human brain in response to hypercapnia and hyperoxia using magnetic resonance imaging
Authors: Shen Yuji , Pu Ida M. , Ahearn Trevor , Clemence Matthew , Schwarzbauer Christian 
Published: April 2012

AbstractHypercapnia and hyperoxia give rise to vasodilation and vasoconstriction, respectively. This study investigates the influence of hypercapnia and hyperoxia on venous vessel size in the human brain. Venous vessel radii were measured in response to hypercapnia and hyperoxia. The venous vessel radii were determined by calculation of the changes in R2* and R2 that are induced by breathing 6% CO2 or pure oxygen. The experimental paradigm consisted of two 3‐min intervals of inhaling 6% CO2 or 100% O2 interleaved with three 2‐min intervals of breathing air. Hypercapnic and hyperoxic experiments were performed on eight subjects on a 3T scanner. Parametric maps of mean venous vessel radius were calculated from the changes in R2* and R2, which were measured by simultaneous acquisition of gradient‐echo and spin‐echo signals. The mean venous vessel radii in hypercapnia were 7.3 ± 0.3 μm in gray matter and 6.6 ± 0.5 μm in white matter. The corresponding vessel radii in hyperoxia were 5.6 ± 0.2 μm in gray matter and 5.4 ± 0.2 μm in white matter. These results show that the venous vessel radius was larger in hypercapnia than that in hyperoxia in both gray matter and white matter (P < 0.005), which agrees with the hypothesis that hypercapnia causes vasodilation and hyperoxia induces vasoconstriction. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
ε‐Caprolactone polymerization under air by the biocatalyst: Magnesium 2,6‐di‐tert‐butyl‐4‐methylphenoxide
Authors: Fang Hsin‐Jou , Lai Ping‐Shan , Chen Jia‐Yun , Hsu Sodio C. N. , Peng Wei‐De , Ou Siou‐Wei , Lai Yi‐Chun , Chen Yen‐Jen , Chung Hsuan , Chen Yun , Huang Ta‐Chou , Wu Bo‐Sheng , Chen Hsuan‐Ying 
Published: April 2012

AbstractThis study investigated the synthesis of the biocatalyst, magnesium 2,6‐di‐tert‐butyl‐4‐methylphenoxide (Mg(BHT)2) complex, and the ring‐opening polymerization (ROP) of ε‐caprolactone (CL). The complex demonstrates high catalytic activity and controllable of molecular weight for the ROP of CL in tetrahydrofuran at room temperature, even when polymerization was performed under air. Before this study, the polymerization of CL had never been performed using a magnesium catalyst under air at room temperature. Various forms of alcohols with different purposes were also used as initiators with Mg(BHT)2. The results show that the magnesium complex acts as a perfect catalyst because of its high catalytic activity and control ability without any cytotoxicity in the polymerization of CL, making it suitable for biomedical applications. In addition, nanoparticle formation, cytotoxicity, and phototoxicity of tri‐2‐hydroxyethyl ester [Ce6‐(CH2CH2OPCL)3] were also studied in this article and Ce6‐(CH2CH2OPCL)3 formed nanoparticle can act as a nanophotosensitizer for photodynamic therapy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Hollow nanoparticles prepared from pH‐responsive template polymer micelles
Authors: Inoue Masamichi , Noda Kyohei , Yusa Shin‐ichi 
Published: April 2012

AbstractWater‐soluble crosslinked hollow nanoparticles were prepared using pH‐responsive anionic polymer micelles as templates. The template micelles were formed from pH‐responsive diblock copolymers (PAMPS‐PAaH) composed of the poly(sodium 2‐(acrylamido)‐2‐methylpropanesulfonate) and poly(6‐(acrylamido)hexanoic acid) blocks in an aqueous acidic solution. The PAMPS and PAaH blocks form a hydrophilic anionic shell and hydrophobic core of the core‐shell polymer micelle, respectively. A cationic diblock copolymer (PEG‐P(APTAC/CEA)) with the poly(ethylene glycol) block and random copolymer block composed of poly((3‐acrylamidopropyl)trimethylammonium chloride) containing a small amount of the 2‐(cinnamoyl)ethylacrylate photo‐crosslinkable unit can be adsorbed to the anionic shell of the template micelle due to electrostatic interaction, which form a core‐shell‐corona three‐layered micelle. The shell of the core‐shell‐corona micelle is formed from a polyion complex with anionic PAMPS and cationic P(APTAC/CEA) chains. The P(APTAC/CEA) chains in the shell of the core‐shell‐corona micelle can be photo‐crosslinked with UV irradiation. The template micelle can be dissociated using NaOH, because the PAaH blocks are ionized. Furthermore, electrostatic interactions between PAMPS and PAPTAC in the shell are screened by adding excess NaCl in water. The template micelles can be completely removed by dialysis against water containing NaOH and NaCl to prepare the crosslinked hollow nanoparticles. Transmission electron microscopy observations confirmed the hollow structure. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Twin liquid crystals and segmented thermotropic polyesters containing azobenzene—effect of spacer length on LC properties
Authors: Nardele Chinmay G. , Asha S. K. 
Published: April 2012

AbstractWe report systematic studies on a homologous series of twin liquid crystalline (LC) molecules based on phenyl and naphthyl azobenzene (PnP and NpnNp) as well as segmented copolyesters based on them. The twin series had the structure azobenzene–oligooxyethylene–azobenzene, where the ethyleneoxy length was varied from 2 to 6 units. The LC properties of the twin series depended on the chemical structure of the azochromophore and also the length of the central oligooxyethylene segment. The PnP series exhibited smectic LC properties for n > three oligooxyethylene units. Conversely, NpnNp series exhibited spherulitic phases only for the shortest member –Np2Np. One non‐LC short spacer twin (P2P) and one LC long spacer twin (P6P) were incorporated as part of a main chain polyester composed of fully aliphatic segments of sebacate and di or tetraethylene glycol (DEG/TEG) units by melt polycondensation. Non‐LC P2P formed LC polymers even at low (5 mol %) incorporation in DEG‐based copolymers, whereas the LC‐P6P could do so only at 30 mol % incorporation. The LC properties of the twin molecules as well as copolymers were studied using differential scanning calorimetry, polarized light microscopy (PLM) along with variable temperature wide angle X‐ray diffraction. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Gamma irradiation of electrospun poly(ε‐caprolactone) fibers affects material properties but not cell response
Authors: Bosworth L. A. , Gibb A. , Downes S. 
Published: April 2012

AbstractFabrication of electrospun fibrous scaffolds as future medical devices is being widely researched, with particular emphasis given to their material properties and effect on cell response and differentiation. However, the vast majority of these scaffolds are sterilized via nonmedically approved methods, including submersion in ethanol and exposure to UV light. Although these techniques are adequate for laboratory‐based research, they are not sufficient for human implantation. In this case, regulatory approved, medical grade sterilization is required. In this study, we report the effects of gamma irradiation, a regulatory approved technique, on electrospun poly(ε‐caprolactone) fibers. Fabricated fibers were separately subjected to different dosages of irradiation ranging from 0 to 45 kGy and then assessed for their physicochemical properties. Gamma irradiation affected fiber properties irrespective of dosage. A dose‐dependent decrease in polymer molecular weight was observed and an increase in melting point and crystallinity reported. Similarly, irradiation had a significant effect on mechanical properties with greatest decrease in tensile strength (68%) for fibers exposed to 40 kGy. The method of sterilization had no effect on cell response. Seeded tenocytes attached to all fibers and elongated parallel to the underlying fiber direction. The results demonstrate the importance of incorporating medical grade sterilization procedures early in the research projects time line to assist translation from bench to clinic. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Thin macroporous silicon heterojunction solar cells
Authors: Ernst Marco , Brendel Rolf , Ferré Rafel , Harder Nils‐Peter 
Published: April 2012

AbstractWe demonstrate the processing of a heterojunction solar cell from a purely macroporous silicon (MacPSi) absorber that is generated and separated from a monocrystalline n‐type Cz silicon wafer by means of electrochemical etching. The etching procedure results in straight pores with a diameter of (4.7 ± 0.2) µm and a distance of 8.3 µm. An intrinsic amorphous Si (a‐Si)/p+‐type a‐Si/indium tin oxide (ITO) layer stack is on the front side and an intrinsic a‐Si/n+‐type a‐Si/ITO layer stack is on the rear side. The pores are open when depositing the layers onto the 3.92 cm2‐sized cell. The conductive layers do not cause shunting through the pores. A silicon oxide layer passivates the pore walls. The energy‐conversion efficiency of the (33 ± 2) µm thick cell is 7.2%. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A critical assessment of surface cloud observations and their use for verifying cloud forecasts
Authors: Mittermaier Marion 
Published: April 2012

AbstractTotal cloud amount and cloud‐base height are two quantities diagnosed from the vertical distribution of cloud in a model grid column. Together they form the basis of many cloud‐based forecast products. Forecasts from four Met Office Unified Model (MetUM) horizontal resolution configurations are compared against manual and automated conventional synoptic (SYNOP) observations. The analysis shows that observation‐type‐dependent characteristics feed through to model forecast biases and skill scores, where manual and automated cloud observations produce biases of opposite kind. The mixing of observation types is therefore not recommended, as the ability to interpret results is compromised. This is especially relevant when tuning model physics. The effect of horizontal grid resolution is mixed on both bias and skill. Copyright © 2012 British Crown copyright, the Met Office Published by John Wiley & Sons Ltd.
Super‐Clausius–Clapeyron scaling of rainfall in a model squall line
Authors: Singleton Andrew , Toumi Ralf 
Published: April 2012

AbstractThe sensitivity of squall rainfall to changes in atmospheric temperature is investigated. For instantaneous rainrates and accumulations up to one hour, extreme rainfall scales with Clausius‐Clapeyron (CC) for temperatures below 24°C and at up to twice CC above 24°C. For longer accumulation periods and higher temperatures the scaling breaks down due to increased propagation of the squall line. For all periods, the storm average rainfall is found to scale at approximately 1.5 times CC over the entire range of temperatures. These results have implications for design parameters for infrastructure that is vulnerable to flooding and for climate change projections. Copyright © 2012 Royal Meteorological Society
Assessing the performance of computational methods for the prediction of the ground state structure of a cyclic decapeptide
Authors: Doemer Manuel , Guglielmi Matteo , Athri Prashanth , Nagornova Natalia S. , Rizzo Thomas R. , Boyarkin Oleg V. , Tavernelli Ivano , Rothlisberger Ursula 
Published: April 2012

AbstractWe benchmark the performance of various computational approaches, ranging from the classical nonpolarizable force fields AMBER FF96 and FF99SB, the polarizable force fields AMBER FF02polEP and AMOEBAbio09 to the semiempirical DFT method SCC‐DFTB. The test set consists of nine conformations of gas‐phase protonated gramicidin S, a cyclic decapeptide. We discuss their structural features in relation to the intrinsic lowest energy structure, which has been solved recently by a combination of cold ion spectroscopy and high level theoretical methods (Nagornova et al., Angew Chem Int Ed 2011, 50, 5383). As a reference, we use the energetics at the M05‐2X level of theory. The latter has been validated as a suitable reference method in predicting the correct ground state structure of gas‐phase protonated bare and microsolvated tryptophan as well as gas‐phase protonated gramicidin S by comparison to experiment. We discuss the performance of the different more approximate methods in relation to their potential use as efficient and reliable tools to explore conformational space for the generation of candidate structures before refinement at the DFT level. © 2012 Wiley Periodicals, Inc.
Selection of prophylactic antibiotics according to the microorganisms isolated from surgical site infections (SSIs) in a previous series of surgeries reduces SSI incidence after pancreaticoduodenectomy
Authors: Kondo Kazuhiro , Chijiiwa Kazuo , Ohuchida Jiro , Kai Masahiro , Fujii Yoshiro , Otani Kazuhiro , Hiyoshi Masahide , Nagano Motoaki , Imamura Naoya 
Published: April 2012

AbstractBackgroundThe incidence of surgical site infections (SSIs) is high after pancreaticoduodenectomy (PD).MethodsWe divided 116 consecutive patients who underwent PD into an early group (n = 58) and a later group (n = 58) according to time of surgery. In both groups, endoscopic retrograde biliary drainage was mainly employed for the patients with obstructive jaundice. In the later group, prophylactic antibiotics were selected according to the susceptibility of microorganisms isolated from SSIs in the early group. The incidence of SSIs was compared between the groups.ResultsThe background characteristics (including methods of preoperative biliary drainage and microorganisms in the bile obtained before or during operation) of the patients were not significantly different between the groups, except for the serum albumin level, which was lower in the later group than in the early group (P = 0.0026). The incidence of SSIs was significantly lower in the later group (24.1 %) than in the early group (46.6 %) (P = 0.0116). Belonging to the later group was one independent negative risk factor for SSI.ConclusionsSelection of prophylactic antibiotics on the basis of microorganisms isolated from SSIs in the early group contributed to the reduced incidence of SSIs in the later group after PD.
Disturbed apoptosis and cell proliferation in developing neuroepithelium of lumbo‐sacral neural tubes in retinoic acid‐induced spina bifida aperta in rat
Authors: Wei Xiaowei , Li Hui , Miao Jianing , Zhou Fenghua , Liu Bo , Wu Di , Li Shujing , Wang Lili , Fan Yang , Wang Weilin , Yuan Zhengwei 
Published: April 2012

AbstractSpina bifida is a complex congenital malformation resulting from failure of fusion in the spinal neural tube during embryogenesis. However, the cellular mechanism underlying spina bifida is not fully understood. Here, we investigated cell apoptosis in whole embryos and proliferation of neural progenitor cells in the spinal neural tube during neurulation in all‐trans retinoic acid (atRA)‐induced spina bifida in fetal rats. Cell apoptosis was assessed by TUNEL assay on whole‐mount and serially sectioned samples of rat embryos with spina bifida. Cell proliferation of lumbo‐sacral neural progenitor cells was assessed by staining for the mitotic marker Ki67 and pH3. We found an excess of apoptosis in the neuroepithelium of embryos with spina bifida, which became more marked as embryos progress from E11 to E13. Conversely, there was a reduction in cell proliferation in spina bifida embryos, with a progressively greater difference from controls with stage from E11 to 13. Thus, atRA‐induced spina bifida in rat shows perturbed apoptosis and proliferation of neural progenitors in the lumbo‐sacral spinal cord during embryonic development, which might contribute to the pathogenesis of spina bifida.
Wall accumulation and spatial localization in particle-laden wall flows
Authors: Sardina G. , Schlatter P. , Brandt L. , Picano F. , Casciola C. M. 
Published: April 2012

AbstractWe study the two main phenomenologies associated with the transport of inertial particles in turbulent flows, turbophoresis and small-scale clustering. Turbophoresis describes the turbulence-induced wall accumulation of particles dispersed in wall turbulence, while small-scale clustering is a form of local segregation that affects the particle distribution in the presence of fine-scale turbulence. Despite the fact that the two aspects are usually addressed separately, this paper shows that they occur simultaneously in wall-bounded flows, where they represent different aspects of the same process. We study these phenomena by post-processing data from a direct numerical simulation of turbulent channel flow with different populations of inertial particles. It is shown that artificial domain truncation can easily alter the mean particle concentration profile, unless the domain is large enough to exclude possible correlation of the turbulence and the near-wall particle aggregates. The data show a strong link between accumulation level and clustering intensity in the near-wall region. At statistical steady state, most accumulating particles aggregate in strongly directional and almost filamentary structures, as found by considering suitable two-point observables able to extract clustering intensity and anisotropy. The analysis provides quantitative indications of the wall-segregation process as a function of the particle inertia. It is shown that, although the most wall-accumulating particles are too heavy to segregate in homogeneous turbulence, they exhibit the most intense local small-scale clustering near the wall as measured by the singularity exponent of the particle pair correlation function.
An analytically predictive model for moderately rarefied gas flow
Authors: Veltzke Thomas , Thöming Jorg 
Published: April 2012

AbstractIn microducts deviation from continuum flow behaviour of a gas increases with rarefaction. When using Navier–Stokes equations to calculate a flow under slightly and moderately rarefied conditions, slip boundary conditions are used which in turn refer to the tangential momentum accommodation coefficient (TMAC). Here we demonstrate that, in the so-called slip and transition regime, the flow in microducts can be reliably described by a consistently non-empirical model without considering the TMAC. We obtain this equation by superposition of convective transport and Fickian diffusion using two-dimensional solutions of Navier–Stokes equations and a description for the Knudsen diffusion coefficient as derived from kinetic theory respectively. For a wide variety of measurement series found in the literature the calculation predicts the data accurately. Surprisingly only size of the duct, temperature, gas properties and inlet and outlet pressure are necessary to calculate the resulting mass flow by means of a single algebraic equation. From this, and taking the discrepancies of the TMAC concerning surface roughness and nature of the gases into account, we could conclude that neither the diffusive proportions nor the total mass flow rates are influenced by surface topology and chemistry at Knudsen numbers below unity. Compared to the tube geometry, the model slightly underestimates the flow rate in rectangular channels when rarefaction increases. Likewise, the dimensionless mass flow rate and the diffusive proportion of the total flow are distinctly higher in a tube. Thus the cross-sectional geometry has a significant influence on the transport mechanisms under rarefied conditions.
Weight change before and after the introduction of solids: results from a longitudinal birth cohort
Authors: Rossem Lenie van , Kiefte-de Jong Jessica C. , Looman Caspar W. N. , Jaddoe Vincent W. V. , Hofman Albert , Hokken-Koelega Anita C. S. , Mackenbach Johan P. , Moll Henriëtte A. , Raat Hein 
Published: April 2012

We studied the association, and its direction, between the introduction of solids and weight-for-height (WFH) change between birth and 45 months. Pregnant women were asked to participate in a birth cohort during their first antenatal visit. Data from 3184 children were used. The timing of the introduction of solids was reported by the mother from a questionnaire at 12 months postpartum, and categorised into very early (0–3 months), early (3–6 months) and timely (after 6 months) introduction of solids. Anthropometric data were collected during standardised child health centre visits. WFH was converted into a z-score. Repeated-measurements analyses with splines positioned according to the moments of solid introduction were used to obtain estimates for WFH change before and after the introduction of solids. Analyses were adjusted for educational level, ethnicity, smoking during pregnancy, mother's BMI, breast-feeding, history of food allergy and infant's hospital admission. Before solids were introduced, weight gain was higher in children introduced to solids early (z= 0·65, 95 % CI 0·34, 0·95) than in children introduced to solids very early (z= 0·02, 95 % CI − 0·03, 0·08) and timely (z= − 0·04, 95 % CI − 0·05, − 0·03). Shortly after the introduction of solids, children introduced to solids very early and early showed a relative decrease in WFH. WFH change did not differ between the solid introduction groups after 12 months, and at that time, weight change was as expected (i.e. z= 0). We therefore conclude that differences in WFH in childhood are not the result of early introduction to solids.