bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaf epidermal characters of Solanum sect. polytrichum (Solanaceae) as taxonomic evidence
Authors: Nurit‐Silva Kiriaki , De Fátima Agra Maria 
Published: May 2011

AbstractThe morphological similarities among the species of Solanum are remarkable, and are often very difficult one clear distinction between them. This paper presents a comparative anatomical study of the leaf epidermis of five Brazilian species of Solanum sect. Polytrichum, carried out using light and scanning electron microscopy. The leaf epidermis surfaces were investigated to evaluate their taxonomic significance to be used for separation and delimitation of the species of the section. As results, some micro‐morphological characters of the leaf epidermis, such as density, distribution and type of stellate trichomes, and the anticlinal walls of epidermal cells, and also the type and distribution of stomata proved to be the most useful and distinctive characters for the separation and delimitation of the species, and also may contribute as an additional support to the interspecific taxonomy and systematic of Solanum sect. Polytrichum. Microsc. Res. Tech., 2011. © 2011 Wiley Periodicals, Inc.
Free body analysis, beam mechanics, and finite element modeling of the mandible of Alligator mississippiensis
Authors: Porro Laura B. , Holliday Casey M. , Anapol Fred , Ontiveros Lupita C. , Ontiveros Lolita T. , Ross Callum F. 
Published: May 2011

AbstractThe mechanical behavior of mammalian mandibles is well‐studied, but a comprehensive biomechanical analysis (incorporating detailed muscle architecture, accurate material properties, and three‐dimensional mechanical behavior) of an extant archosaur mandible has never been carried out. This makes it unclear how closely models of extant and extinct archosaur mandibles reflect reality and prevents comparisons of structure–function relationships in mammalian and archosaur mandibles. We tested hypotheses regarding the mechanical behavior of the mandible of Alligator mississippiensis by analyzing reaction forces and bending, shear, and torsional stress regimes in six models of varying complexity. Models included free body analysis using basic lever arm mechanics, 2D and 3D beam models, and three high‐resolution finite element models of the Alligator mandible, incorporating, respectively, isotropic bone without sutures, anisotropic bone with sutures, and anisotropic bone with sutures and contact between the mandible and the pterygoid flange. Compared with the beam models, the Alligator finite element models exhibited less spatial variability in dorsoventral bending and sagittal shear stress, as well as lower peak values for these stresses, suggesting that Alligator mandibular morphology is in part designed to reduce these stresses during biting. However, the Alligator models exhibited greater variability in the distribution of mediolateral and torsional stresses than the beam models. Incorporating anisotropic bone material properties and sutures into the model reduced dorsoventral and torsional stresses within the mandible, but led to elevated mediolateral stresses. These mediolateral stresses were mitigated by the addition of a pterygoid‐mandibular contact, suggesting important contributions from, and trade‐offs between, material properties and external constraints in Alligator mandible design. Our results suggest that beam modeling does not accurately represent the mechanical behavior of the Alligator mandible, including important performance metrics such as magnitude and orientation of reaction forces, and mediolateral bending and torsional stress distributions. J.Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Comparative retinal morphology of the platypus
Authors: Zeiss Caroline J. , Schwab Ivan R. , Murphy Christopher J. , Dubielzig Richard W. 
Published: May 2011

AbstractThe purpose of this study is to identify evolutionary origin and fate of anatomic features of the duck‐billed platypus eye. Eyes from the duck‐billed platypus and four key evolutionary basal vertebrates (Pacific hagfish, north hemisphere sea lamprey, and Australian and South American lungfishes) were prepared for light microscopy. In addition to a standard panel of stains, tissues were immunostained against a variety of rod and cone opsins. Finally, published opsin sequences of platypus and several other vertebrate species were aligned and compared with immunohistochemical results. A complete scleral cartilage similar to that seen in birds, reptiles and amphibians encloses the platypus eye. This feature is present in sharks and rays, and in extant relatives of tetrapods, the lungfishes. The choroid lacks a tapetum. The retina is largely avascular and is rod‐dominated, with a minority of red‐ and blue‐ cone immunoreactive photoreceptors. Like marsupials and many nonmammalian vertebrates, cones contain clear inner segment droplets. Double cones were present, a feature not found in eutherian mammals or marsupials. Evaluation of opsins indicates that red and blue immunoreactive cone opsins, but not rhodopsin, are present in the most basal of the extant species examined, the Pacific hagfish. Rhodopsin appears in the Australian and South American lungfishes, establishing emergence of this pigment in an extant relative of tetrapods. Unlike eyes of eutherian mammals, the platypus eye has retained morphologic features present in early tetrapods such as amphibians and their evolutionarily basal sister group, the lungfishes. These include scleral cartilage, double cones and cone droplets. In the platypus, as in other mammals, rod rhodopsin is the predominant photoreceptor pigment, at expense of the cone system. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Acute hepatitis C in Korea: Different modes of infection, high rate of spontaneous recovery, and low rate of seroconversion
Authors: Kim Jong Yeop , Won Ji Eon , Jeong Sook‐Hyang , Park Sang Jong , Hwang Seong Gyu , Kang Sook‐Kyoung , Bae Si Hyun , Kim Young Seok , Lee Han Chu 
Published: May 2011

AbstractThe epidemiology and clinical outcomes of acute hepatitis C are different geographically. This study aimed to investigate the mode of infection, clinical characteristics, and outcomes of acute hepatitis C in Korea. Forty‐seven patients with acute hepatitis C were enrolled consecutively in a study conducted in seven medical centers. The patients with the mean age of 45.8 years had mostly mild symptoms. A healthcare‐related procedure was the most common exposure history (42.5%): acupuncture (17%), surgery (10.6%), needle‐stick injury (8.5%), and other medical procedures (6.4%). There was no case of intravenous drug use. Twenty‐one patients (44.7%) recovered spontaneously. Among the 16 patients who received antiviral therapy (34%), all of the 12 evaluable patients had a sustained virologic response, while 10 patients (21.3%) who did not receive antiviral therapy progressed to chronic infection. The overall seroconversion rate of anti‐HCV antibody was 61.7%. The patients who recovered spontaneously had significantly lower rate of seroconversion compared with the patients who did not clear spontaneously the infection. In conclusion, acute hepatitis C in Korea was related to various healthcare procedures, including acupuncture, characterized by high rates of spontaneous recovery and low rates of seroconversion, which may be associated with different modes of infection and ethnic differences. The characteristics of acute hepatitis C in Asian countries warrants further study. J. Med. Virol. 83:1195–1202, 2011. © 2011 Wiley‐Liss, Inc.
Torn human rotator cuff tendons have reduced collagen thermal properties on differential scanning calorimetry
Authors: Chaudhury Salma , Holland Christopher , Porter David , Tirlapur Uday K. , Vollrath Fritz , Carr Andrew J 
Published: May 2011

AbstractThe cause of the high failure rates often observed following rotator cuff tendon repairs, particularly massive tears, is not fully understood. Collagen structural changes have been shown to alter tendon thermal and mechanical properties. This study aimed to form a quantitative rather than qualitative assessment, of whether differences in collagen structure and integrity existed between small biopsies of normal, small, and massive rotator cuff tears using differential scanning calorimetry. Thermal properties were measured for 28 human biopsies taken intra‐operatively from normal, small, and massive rotator cuff tendon tears in this powered study. Denaturation temperatures are represented by Tonset (°C) and Tpeak (°C). The Tonset is proposed to represent water‐amide hydrogen bond breakage and resulting protein backbone mobility. Tpeak reportedly corresponds to the temperature at which the majority of proteins fall out of solution. Denaturation enthalpy (ΔH) should correlate with the amount of triple helical structure that is denatured. Fluorescence and confocal microscopy allowed quantitative validation. Small and massive rotator cuff tears had significantly higher Tonset, Tpeak, and ΔH compared to controls. Polarized light microscopy of torn tendons confirmed greater collagen structural disruption compared to controls. These novel findings suggest greater quantifiable collagen structural disruption in rotator cuff tears, compared to controls. This study offers insight into possible mechanisms for the reduced strength of torn tendons and may explain why repaired tendons fail to heal. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1938–1943, 2011
Polarization‐dependent Raman spectroscopy of LiBH4 single crystals and Mg(BH4)2 powders
Authors: Gebert Florian , Willenberg Britta , van Setten Michiel J. , Bardají Elisa G. , Roehm Eva , Fichtner Maximilian , Schoenes Joachim 
Published: May 2011

AbstractThe phonons and the crystal structure of the complex hydride LiBH4 are studied on single crystals using micro‐Raman spectroscopy. The symmetry of the modes is determined by polarization‐dependent measurements at liquid helium temperature, allowing a better comparison and a more reliable assignment to the computed phonon wavenumbers. This has led to the revision of some former assignments made from Raman measurements on polycrystalline samples. In addition, a higher integration time allowed the detection of very weak lines, so that 35 out of 36 predicted Raman lines have been identified. We have also performed explorative Raman measurements on Mg(BH4)2 powders. In contrast to LiBH4, the very poor crystallinity of this material inhibits the exploitation of the full potential of Raman spectroscopy. Only broad lines are observed, which we compare to phonon wavenumbers calculated for various possible structures using density functional theory. Copyright © 2011 John Wiley & Sons, Ltd.
A detachable SERS active cellulose film: a minimally invasive approach to the study of painting lakes
Authors: Doherty B. , Brunetti B. G. , Sgamellotti A. , Miliani C. 
Published: May 2011

AbstractThe design and synthesis of a tailor‐made surface‐enhanced Raman scattering (SERS) active film that is fabricated to be removable from the surface of an artwork under study following effective measurements is detailed. It is shown that silver nanoparticles prepared by green chemical reduction with glucose can be effectively doped into a methylcellulose (MC) matrix for the formation of a gel, which can be subsequently applied to a minute area (ca 1–1.5 mm) of an artwork without posing a threat to its integrity. Studies have been aimed at characterizing this film's chemical and physical properties, with regard to the stability of the nanoparticles dispersed within the MC, the ease of application of the viscous gel, its speed of drying and the transparency of the dry film for SERS measurements. Importantly, results have led to reproducible SERS enhancements of the order 103–104 for studies carried out on reference laboratory dye components and unvarnished mock‐paintings. Techniques including optical and scanning electron microscopy were used to monitor the drying of the film and its resulting morphology, as well as to map the distribution of silver nanoparticles in the film so as to account for any visual modification to the underlying surface upon film removal. Copyright © 2011 John Wiley & Sons, Ltd.
Frohlich interaction and associated resonance enhancement in nanostructured copper oxide films
Authors: Mohemmed Shanid N. A. , Abdul Khadar M. , Sathe V. G. 
Published: May 2011

AbstractNanostructured copper oxide films were prepared by the oxidation of copper films by thermal evaporation of metallic copper. Analysis of HRTEM images showed that the films of Cu2O and CuO phases had. The band gap of the nanostructured sample of Cu2O was suitable for resonance scattering by intraband Fröhlich interaction in this sample. Micro‐Raman studies revealed an intense resonance Raman peak corresponding to a forbidden mode of Cu2O. Copyright © 2011 John Wiley & Sons, Ltd.
Herman–Wallis correction in vibrational CARS of oxygen
Authors: Marrocco Michele 
Published: May 2011

AbstractLight molecules are subject to vibration–rotation (VR) interaction, which implies corrections to the rigid rotor approximation and, in particular, corrections to spectral line intensities are related to the so‐called Herman–Wallis (HW) factor. This problem is outlined here for the spectral response of some medium‐weight diatomics in the gas phase and probed by means of vibrational coherent anti‐Stokes Raman scattering (CARS) used for diagnostic reasons in combustion science. However, different from other works on this subject, we specialized our analysis to oxygen and, since the peculiarity of its anti‐bonding molecular orbital, we find that the VR coupling is responsible for deviations that compete with the effect of Raman line widths typical of collisional environments of hot gases at room pressure. The HW correction is ultimately demonstrated to affect O2 CARS thermometry in such a manner that the accuracy for measurements at high temperatures can be improved. Copyright © 2011 John Wiley & Sons, Ltd.
Identifying habitat linkages to maintain connectivity for corridor dwellers in a fragmented landscape
Authors: Barrows Cameron W. , Fleming Kathleen D. , Allen Michael F. 
Published: May 2011

AbstractAnthropogenic habitat fragmentation typically precedes conservation planning; maintaining remaining linkages among core habitat areas can thus become a key conservation objective. Identifying linkages for dispersal and ensuring those linkages have long‐term protection and management are challenging tasks for wildlife managers. These tasks can be especially daunting for smaller species with low mobility, termed corridor dwellers, which must maintain sustainable populations within corridors. Between May 2007 and June 2009, we collected occurrence locations for a corridor dweller, the Palm Springs pocket mouse (Perognathus longimembris bangsii), from museums, previous research, and our own field sampling. We used those data to model their suitable niche space and then identify suitable linkages between proposed conservation areas. We used a partitioned Mahalanobis D2 statistic to create a spatially explicit niche model describing the distribution of a suitable niche space, and we validated the model statistically, with live trapping and with burrowing owl (Athene cunnicularia) diets. Our model identified soil characteristics, topographic ruggedness, and vegetation as variables delimiting Palm Springs pocket mouse habitat; sand content of the soils was an especially important characteristic. Our historic distribution model identified 120,000–90,000 ha as historically potential Palm Springs pocket mouse habitat; roughly 39% of that has been lost to more recent development. Most of the remaining suitable habitat occurred in the northwestern portion of the valley. We modeled habitat within core reserves as well as within proposed linkages between those reserves as having high similarity to known occupied habitats. Live trapping in areas with high (≥0.95) Habitat Suitability Index (HSI) values resulted in captures at 66% of those locations and, along with burrowing owl diets, refined a qualitative model as to what constituted a suitable Palm Springs pocket mouse corridor. While most corridor analyses have focused on mobile species which may traverse corridors in hours, days, or weeks, linkages for corridor dwellers must include habitat for sustaining multi‐generational populations. This requires evaluating whether continuous suitable habitat exists within proposed corridors. Our research demonstrates how niche modeling can provide a landscape‐scale view of the distribution of suitable habitat to evaluate conservation objectives for connectivity. © 2011 The Wildlife Society.
Application of the simple saddlepoint approximation to estimate probability distributions in wildlife research
Authors: Demaso Stephen J. , Hernández Fidel , Brennan Leonard A. , Bingham Ralph L. 
Published: May 2011

AbstractThe simple saddlepoint approximation (SSA) uses the mean, variance, and skewness (a measure of the asymmetry of the distribution) of a data set to algebraically approximate the probability density function of a selected variable. We compared habitat‐suitability bounds estimated with SSAs and continuous selection functions. Habitat‐suitability bounds for bobwhite nesting based on the SSA method were biologically comparable to the results of the method based on continuous selection functions. The SSA approach allows habitat‐suitability bounds to be estimated using algebra and can be calculated in computer spreadsheets. © 2011 The Wildlife Society.
Evaluation of noninvasive genetic sampling methods for cougars in Yellowstone National Park
Authors: Sawaya Michael A. , Ruth Toni K. , Creel Scott , Rotella Jay J. , Stetz Jeffrey. B. , Quigley Howard B. , Kalinowski Steven T. 
Published: May 2011

AbstractConventional methods for monitoring cougar, Puma concolor, populations involve capture, tagging, and radio‐collaring, but these methods are time‐consuming, expensive, and logistically challenging. For difficult‐to‐study species such as cougars, noninvasive genetic sampling (NGS) may be a useful alternative. The ability to identify individuals from samples collected through NGS methods provides many opportunities for developing population‐monitoring tools, but the utility of these survey methods is dependent upon collection of samples and accurate genotyping of those samples. In January 2003, we initiated a 3‐yr evaluation of NGS methods for cougars using a radio‐collared population in Yellowstone National Park (YNP), USA. Our goals were to: 1) determine which DNA collection method, hair snares or snow tracking, provided a better method for obtaining samples for genetic analysis, 2) evaluate reliability of the genetic data derived from hair samples collected in the field, and 3) evaluate the potential of NGS for demographic monitoring of cougar populations. Snow tracking yielded more hair samples and was more cost effective than snagging hair with rub pads. Samples collected from bed sites and natural hair snags (e.g., branch tips, thorn bushes) while snow tracking accurately identified and sexed 22 individuals (9 F, 13 M). The ratio of the count from snow tracking to the count from radio‐telemetry was 15:24 in winter 2004, 13:12 in 2005, and 22:29 for both years combined. Annual capture probabilities for obtaining DNA from snow tracking varied considerably between years for females (0.42 in 2004 and 0.88 in 2005) but were more consistent for males (0.77 in 2004 and 0.88 in 2005). Our results indicate that snow tracking can be an efficient, reliable NGS method for cougars in YNP and has potential for estimating demographic and genetic parameters of other carnivore populations in similar climates. © 2011 The Wildlife Society.
Narrow Bandgap Donor–Acceptor Conjugated Polymer: Synthesis, Properties and Photovoltaic Application
Authors: Zhao Chunchang , Feng Peng , Chen Xiaohong , Ng Man‐Kit 
Published: May 2011

AbstractNew soluble, narrow bandgap bithiophene‐based conjugated polymer poly[3‐(1,4‐dihydro‐5,8‐didodecanoxy‐1,4‐methano‐naphthalen‐6‐yl)‐2,2′‐bithiophene‐5,5′‐diyl(2‐cyano‐1,2‐ethenediyl)‐1,4‐diphenylene(1‐cyano‐1,2‐ethenediyl)] (PBT‐PDCN) has been synthesized by Knoevenagel polycondensation method. PBT‐PDCN exhibits high solubility in common organic solvents. Optical studies show that the higher‐energy absorption band of PBT‐PDCN is red‐shifted with increasing polarity of solvents from toluene to THF, and from solution to solid film. Electrochemical characterizations revealed that polymer PBT‐PDCN has a low bandgap. The hole mobility was found to be 1.4 · 10−4 cm2 V−1 s−1. Bulk heterojunction solar cells have been fabricated using blends of PBT‐PDCN with PCBM in different ratios. The best solar cell performance obtained was based on the blend of PBT‐PDCN with PCBM in 1:3 weight ratio with the power conversion efficiency reaching 0.71%. The photocurrent action spectrum showed a broad curve between 400 nm and 700 nm, with an external quantum efficiency (EQE) maximum of 20% at 570 nm, matching the PBT‐PDCN absorption spectrum very closely. magnified image
Radiation‐Induced Graft Copolymerization of Styrene into Tetrafluoroethylene‐Hexafluoropropylene‐Vinylidene Fluoride (THV) Terpolymer Films
Authors: Lappan Uwe , Geißler Uwe , Gohs Uwe 
Published: May 2011

AbstractThe objective of this work was to investigate the influence of irradiation conditions on grafting of styrene into tetrafluoroethylene‐hexafluoropropylene‐vinylidene fluoride (THV) terpolymer films. Stress–strain measurements, infrared spectroscopy and electron paramagnetic resonance spectroscopy have been used to characterize the pre‐irradiated polymer films regarding tensile strength, elongation at break, changes in the chemical structure and concentration of trapped radicals, respectively. Main‐chain scissions associated with the formation of carbonyl end groups and end‐chain double bond structures have been identified to be the reason for a moderate deterioration of the mechanical properties of the pre‐irradiated films. The yield of grafting has been found to be influenced by THV grade, irradiation temperature and concentration of cross‐linker. magnified image
RAFT Polymerization and Thiol Chemistry: A Complementary Pairing for Implementing Modern Macromolecular Design
Authors: Roth Peter J. , Boyer Cyrille , Lowe Andrew B. , Davis Thomas P. 
Published: May 2011

AbstractReversible addition fragmentation chain transfer (RAFT) polymerization is one of the most extensively studied reversible deactivation radical polymerization methods for the production of well‐defined polymers. After polymerization, the RAFT agent end‐group can easily be converted into a thiol, opening manifold opportunities for thiol modification reactions. This review is focused both on the introduction of functional end‐groups using well‐established methods, such as thiol‐ene chemistry, as well as on creating bio‐cleavable disulfide linkages via disulfide exchange reactions. We demonstrate that thiol modification is a highly attractive and efficient chemistry for modifying RAFT polymers. magnified image