bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rationale, design and methodology for Intraventricular Pressure Gradients Study: a novel approach for ventricular filling assessment in normal and falling hearts
Authors: Guerra Miguel , Amorim Mário J , Mota João C , Vouga Luís , Leite-Moreira# Adelino 
Published: May 2011

Abstract

Background
Intraventricular pressure gradients have been described between the base and the apex of the left ventricle during early diastolic ventricular filling, as well as, their increase after systolic and diastolic function improvement. Although, systolic gradients have also been observed, data are lacking on their magnitude and modulation during cardiac dysfunction. Furthermore, we know that segmental dysfunction interferes with the normal sequence of regional contraction and might be expected to alter the physiological intraventricular pressure gradients. The study hypothesis is that systolic and diastolic gradients, a marker of normal left ventricular function, may be related to physiological asynchrony between basal and apical myocardial segments and they can be attenuated, lost entirely, or even reversed when ventricular filling/emptying is impaired by regional acute ischemia or severe aortic stenosis.

Methods/Design

Animal Studies: Six rabbits will be completely instrumented to measuring apex to outflow-tract pressure gradient and apical and basal myocardial segments lengthening changes at basal, afterloaded and ischemic conditions. Afterload increase will be performed by abruptly narrowing or occluding the ascending aorta during the diastole and myocardial ischemia will be induced by left coronary artery ligation, after the first diagonal branch.

Patient Studies: Patients between 65-80 years old (n = 12), both genders, with severe aortic stenosis referred for aortic valve replacement will be selected as eligible subjects. A high-fidelity pressure-volume catheter will be positioned through the ascending aorta across the aortic valve to measure apical and outflow-tract pressure before and after aortic valve replacement with a bioprosthesis. Peak and average intraventricular pressure gradients will be recorded as apical minus outflow-tract pressure and calculated during all diastolic and systolic phases of cardiac cycle.

Discussion
We expect to validate the application of our method to obtain intraventricular pressure gradients in animals and patients and to promote a methodology to better understand the ventricular relaxation and filling and their correlation with systolic function.
Car sunshade-induced craniofacial injury: a case report
Authors: Sharif-Alhoseini Mahdi , Khatibi Hadi , Chardoli Mojtaba , Rahimi-Movaghar Vafa 
Published: May 2011

Abstract

Introduction
We report the case of a man who sustained a craniofacial injury after spontaneous lateral airbag deployment resulting in his face being struck by a car sunshade. This highlights the potential damage that can be caused by any object placed between a lateral airbag and a car occupant.

Case presentation
We report the case of a 33-year-old Caucasian man who was the driver in a frontal collision. He had opened the car sunshade and turned it 90° towards the left. As he was driving, he struck a bus, causing the driver's lateral airbag to spontaneously deploy. The airbag pushed the sunshade against his face and injured him.

Conclusions
Car sunshades can cause significant craniofacial injury. We suggest that sunshade design must be improved to reduce the risk of potential injuries to car occupants. We recommend a new, safer sunshade design.
A Metabolic Biofuel Cell: Conversion of Human Leukocyte Metabolic Activity to Electrical Currents
Authors: Justin Gusphyl A , Zhang Yingze , Cui X Tracy , Bradberry Charles W , Sun Mingui , Sclabassi Robert J 
Published: May 2011

Abstract
An investigation of the electrochemical activity of human white blood cells (WBC) for biofuel cell (BFC) applications is described. WBCs isolated from whole human blood were suspended in PBS and introduced into the anode compartment of a proton exchange membrane (PEM) fuel cell. The cathode compartment contained a 50 mM potassium ferricyanide solution. Average current densities between 0.9 and 1.6 μA cm-2 and open circuit potentials (Voc) between 83 and 102 mV were obtained, which were both higher than control values. Cyclic voltammetry was used to investigate the electrochemical activity of the activated WBCs in an attempt to elucidate the mechanism of electron transfer between the cells and electrode. Voltammograms were obtained for the WBCs, including peripheral blood mononuclear cells (PBMCs - a lymphocyte-monocyte mixture isolated on a Ficoll gradient), a B lymphoblastoid cell line (BLCL), and two leukemia cell lines, namely K562 and Jurkat. An oxidation peak at about 363 mV vs. SCE for the PMA (phorbol ester) activated primary cells, with a notable absence of a reduction peak was observed. Oxidation peaks were not observed for the BLCL, K562 or Jurkat cell lines. HPLC confirmed the release of serotonin (5-HT) from the PMA activated primary cells. It is believed that serotonin, among other biochemical species released by the activated cells, contributes to the observed BFC currents.
Prevalence of sacral dysmorphia in a prospective trauma population: Implications for a "safe" surgical corridor for sacro-iliac screw placement
Authors: Hasenboehler Erik A , Stahel Philip F , Williams Allison , Smith Wade R , Newman Justin T , Symonds David L , Morgan Steven J 
Published: May 2011

AbstractBackgroundPercutaneous sacro-iliac (SI) screw fixation represents a widely used technique in the management of unstable posterior pelvic ring injuries and sacral fractures. The misplacement of SI-screws under fluoroscopic guidance represents a critical complication for these patients. This study was designed to determine the prevalence of sacral dysmorphia and the radiographic anatomy of surgical S1 and S2 corridors in a representative trauma population.MethodsProspective observational cohort study on a consecutive series of 344 skeletally mature trauma patients of both genders enrolled between January 1, 2007, to September 30, 2007, at a single academic level 1 trauma center. Inclusion criteria included a pelvic CT scan as part of the initial diagnostic trauma work-up. The prevalence of sacral dysmorphia was determined by plain radiographic pelvic films and CT scan analysis. The anatomy of sacral corridors was analyzed on 3 mm reconstruction sections derived from multislice CT scan, in the axial, coronal, and sagittal plane. "Safe" potential surgical corridors at S1 and S2 were calculated based on these measurements.ResultsRadiographic evidence of sacral dysmorphia was detected in 49 patients (14.5%). The prevalence of sacral dysmorphia was not significantly different between male and female patients (12.2%vs. 19.2%;P= 0.069). In contrast, significant gender-related differences were detected with regard to radiographic analysis of surgical corridors for SI-screw placement, with female trauma patients (n= 99) having significantly narrower corridors at S1 and S2 in all evaluated planes (axial, coronal, sagittal), compared to male counterparts (n= 245;P< 0.01). In addition, the mean S2 body height was higher in dysmorphic compared to normal sacra, albeit without statistical significance (P= 0.06), implying S2 as a safe surgical corridor of choice in patients with sacral dysmorphia.ConclusionsThese findings emphasize a high prevalence of sacral dysmorphia in a representative trauma population and imply a higher risk of SI-screw misplacement in female patients. Preoperative planning for percutaneous SI-screw fixation for unstable pelvic and sacral fractures must include a detailed CT scan analysis to determine the safety of surgical corridors.
The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City
Authors: Diaz-Badillo Alvaro , Bolling Bethany G , Perez-Ramirez Gerardo , Moore Chester G , Martinez-Munoz Jorge P , Padilla-Viveros America A , Camacho-Nuez Minerva , Diaz-Perez Alfonso , Beaty Barry J , de Lourdes Munoz Maria 
Published: May 2011

Abstract

Background

Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids.

Results
Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected.

Conclusions
Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.
Aerodynamics of tip-reversal upstroke in a revolving pigeon wing
Authors: Crandell Kristen E. , Tobalske Bret W. 
Published: May 2011

SUMMARYDuring slow flight, bird species vary in their upstroke kinematics using either a ‘flexed wing’ or a distally supinated ‘tip-reversal’ upstroke. Two hypotheses have been presented concerning the function of the tip-reversal upstroke. The first is that this behavior is aerodynamically inactive and serves to minimize drag. The second is that the tip-reversal upstroke is capable of producing significant aerodynamic forces. Here, we explored the aerodynamic capabilities of the tip-reversal upstroke using a well-established propeller method. Rock dove (Columba livia, N=3) wings were spread and dried in postures characteristic of either mid-upstroke or mid-downstroke and spun at in vivo Reynolds numbers to simulate forces experienced during slow flight. We compared 3D wing shape for the propeller and in vivo kinematics, and found reasonable kinematic agreement between methods (mean differences 6.4% of wing length). We found that the wing in the upstroke posture is capable of producing substantial aerodynamic forces. At in vivo angles of attack (66 deg at mid-upstroke, 46 deg at mid-downstroke), the upstroke wings averaged for three birds produced a lift-to-drag ratio of 0.91, and the downstroke wings produced a lift-to-drag ratio of 3.33. Peak lift-to-drag ratio was 2.5 for upstroke and 6.3 for downstroke. Our estimates of total force production during each half-stroke suggest that downstroke produces a force that supports 115% of bodyweight, and during upstroke a forward-directed force (thrust) is produced at 36% of body weight.
Mechanisms underlying rhythmic locomotion: dynamics of muscle activation
Authors: Chen Jun , Tian Jianghong , Iwasaki Tetsuya , Friesen W. Otto 
Published: May 2011

SUMMARYWe have studied the dynamical properties of tension development in leech longitudinal muscle during swimming. A new method is proposed for modeling muscle properties under functionally relevant conditions where the muscle is subjected to both periodic activation and rhythmic length changes. The ‘dual-sinusoid’ experiments were conducted on preparations of leech nerve cord and body wall. The longitudinal muscle was activated periodically by injection of sinusoidal currents into an identified motoneuron. Simultaneously, sinusoidal length changes were imposed on the body wall with prescribed phase differences (12 values equally spaced over 2π radians) with respect to the current injection. Through the singular value decomposition of appropriately constructed tension data matrices, the leech muscle was found to have a multiplicative structure in which the tension was expressed as the product of activation and length factors. The time courses of activation and length factors were determined from the tension data and were used to develop component models. The proposed modeling method is a general one and is applicable to contractile elements for which the effects of series elasticity are negligible.
Seasonal plasticity of auditory hair cell frequency sensitivity correlates with plasma steroid levels in vocal fish
Authors: Rohmann Kevin N. , Bass Andrew H. 
Published: May 2011

SUMMARYVertebrates displaying seasonal shifts in reproductive behavior provide the opportunity to investigate bidirectional plasticity in sensory function. The midshipman teleost fish exhibits steroid-dependent plasticity in frequency encoding by eighth nerve auditory afferents. In this study, evoked potentials were recorded in vivo from the saccule, the main auditory division of the inner ear of most teleosts, to test the hypothesis that males and females exhibit seasonal changes in hair cell physiology in relation to seasonal changes in plasma levels of steroids. Thresholds across the predominant frequency range of natural vocalizations were significantly less in both sexes in reproductive compared with non-reproductive conditions, with differences greatest at frequencies corresponding to call upper harmonics. A subset of non-reproductive males exhibiting an intermediate saccular phenotype had elevated testosterone levels, supporting the hypothesis that rising steroid levels induce non-reproductive to reproductive transitions in saccular physiology. We propose that elevated levels of steroids act via long-term (days to weeks) signaling pathways to upregulate ion channel expression generating higher resonant frequencies characteristic of non-mammalian auditory hair cells, thereby lowering acoustic thresholds.
Striped marsh frog (Limnodynastes peronii) tadpoles do not acclimate metabolic performance to thermal variability
Authors: Niehaus Amanda C. , Wilson Robbie S. , Seebacher Frank , Franklin Craig E. 
Published: May 2011

SUMMARYHuman-induced climate change is predicted to affect not only the mean temperature of the environment but also the variability and frequency of extreme climatic events. Variability in an organism's developmental environment has the potential to markedly affect an individual's growth trajectory and physiological function, leading to impacts on individual fitness and population dynamics. Thus, it is important to consider the consequences of thermal variability on developing organisms and understand their capacity to respond to such increased variation. We investigated the capacity of larval striped marsh frogs (Limnodynastes peronii) to initiate a response to increases in the thermal variability of their developmental environment by reducing the sensitivity of their physiological rate functions to changes in temperature. In variable environments, we expected the thermal sensitivity of rate functions to decrease and their performance breadth to widen so as to buffer the effect of thermal variability. We raised larvae in stable (24°C), narrowly variable (22–26°C; mean 24°C) and widely variable (14–34°C; mean 24°C) thermal environments and measured the thermal sensitivity of their locomotor performance, heart rate, oxygen consumption and activities of two metabolic enzymes, lactate dehydrogenase and cytochrome c oxidase. We found that the temperature-dependent relationships of these physiological functions did not differ between tadpoles raised in stable or variable thermal conditions. Furthermore, the Q10 values of each response variable were virtually unaffected by treatment when measured over the entire thermal range. Our results reveal that larval amphibians exhibit little plasticity in metabolic traits to thermal variability. This lack of plasticity may have important implications for the growth and population dynamics of organisms in environments that are beginning to experience increased thermal variability.
Fibroblasts from long-lived bird species are resistant to multiple forms of stress
Authors: Harper James M. , Wang Min , Galecki Andrzej T. , Ro Jennifer , Williams Joseph B. , Miller Richard A. 
Published: May 2011

SUMMARY
Evolutionary senescence theory postulates that aging results from the declining force of natural selection with increasing chronological age. A goal of comparative studies in the biology of aging is to identify genetic and biochemical mechanism(s) driving species-specific differences in the aging process that are the end product of life history trade-offs. We hypothesized that cells from long-lived bird species are more resistant to stress agents than are cells from short-lived species, and that cells from birds are more resistant to stress than are cells from relatively short-lived mammals of similar size. We tested primary fibroblast cultures from 35 species of free-living birds for their resistance to multiple forms of cellular stress and found that cell lines from longer-lived species were resistant to death caused by cadmium (R2=0.27, P=0.002), paraquat (R2=0.13, P=0.03), hydrogen peroxide (R2=0.09, P=0.07) and methyl methanesulfonate (R2=0.13, P=0.03), as well as to the metabolic inhibition seen in low-glucose medium (R2=0.37, P&lt;0.01). They did not differ in their resistance to UV radiation, or to thapsigargin or tunicamycin, inducers of the unfolded protein response. These results were largely consistent even after accounting for the influence of body mass and phylogeny. Cell lines from longer-lived bird species also proliferate more rapidly than cells from short-lived birds, although there was no relationship between proliferation and stress resistance. Finally, avian fibroblasts were significantly more resistant than rodent fibroblasts to each of the tested stressors. These results support the idea that cellular resistance to injury may be an important contributor to the evolution of slow aging and long lifespan among bird species, and may contribute to the relatively long lifespan of birds compared with rodents of the same body size.
Proteomic response to elevated PCO2 level in eastern oysters, Crassostrea virginica: evidence for oxidative stress
Authors: Tomanek Lars , Zuzow Marcus J. , Ivanina Anna V. , Beniash Elia , Sokolova Inna M. 
Published: May 2011

SUMMARY
Estuaries are characterized by extreme fluctuations in CO2 levels due to bouts of CO2 production by the resident biota that exceed its capacity of CO2 consumption and/or the rates of gas exchange with the atmosphere and open ocean waters. Elevated partial pressures of CO2 (PCO2; i.e. environmental hypercapnia) decrease the pH of estuarine waters and, ultimately, extracellular and intracellular pH levels of estuarine organisms such as mollusks that have limited capacity for pH regulation. We analyzed proteomic changes associated with exposure to elevated PCO2 in the mantle tissue of eastern oysters (Crassostrea virginica) after 2 weeks of exposure to control (∼39 Pa PCO2) and hypercapnic (∼357 Pa PCO2) conditions using two-dimensional gel electrophoresis and tandem mass spectrometry. Exposure to high PCO2 resulted in a significant proteome shift in the mantle tissue, with 12% of proteins (54 out of 456) differentially expressed under the high PCO2 compared with control conditions. Of the 54 differentially expressed proteins, we were able to identify 17. Among the identified proteins, two main functional categories were upregulated in response to hypercapnia: those associated with the cytoskeleton (e.g. several actin isoforms) and those associated with oxidative stress (e.g. superoxide dismutase and several peroxiredoxins as well as the thioredoxin-related nucleoredoxin). This indicates that exposure to high PCO2 (∼357 Pa) induces oxidative stress and suggests that the cytoskeleton is a major target of oxidative stress. We discuss how elevated CO2 levels may cause oxidative stress by increasing the production of reactive oxygen species (ROS) either indirectly by lowering organismal pH, which may enhance the Fenton reaction, and/or directly by CO2 interacting with other ROS to form more free radicals. Although estuarine species are already exposed to higher and more variable levels of CO2 than other marine species, climate change may further increase the extremes and thereby cause greater levels of oxidative stress.
Syntheses of High Molecular Weight Poly(l-phenyllactic acid)s by a Direct Polycondensation in the Presence of Stable Lewis Acids
Authors: Nguyen Hieu Duc , Jin Xin , Kaneko Daisaku , Kaneko Tatsuo 
Published: May 2011

Abstract
Poly(l-phenyllactic acid)s (PlPhLAs) with high molecular weight were prepared by a direct polycondensation of l-phenyllactic acid in the presence of stable Lewis acids such as HfCl4·2THF under various reaction conditions. As a result, PlPhLAs with a number-average molecular weight (Mn) more than 100000 g mol−1 were obtained and showed specific optical rotation [α ]D25 of −46° and the glass-transition temperature (Tg) of 55 °C whose absolute values were higher than the reported values and was comparable with Tg of poly(l-lactic acid).
Synthesis and Characterization of Surface-modified FePt Nanocrystals by Supercritical Hydrothermal Method
Authors: Arita Toshihiko , Hitaka Hidetsugu , Minami Kimitaka , Naka Takashi , Adschiri Tadafumi 
Published: May 2011

Abstract
We have synthesized single nanosized FePt nanocrystals (NCs) by supercritical (sc-) hydrothermal synthesis. The synthesized FePt NCs were characterized by X-ray diffraction (XRD), transmission electron micrography (TEM), electron diffraction (ED), superconducting quantum interference device magnetometry (SQUID), and Fourier transform infrared spectroscopy (FTIR). Surface modification with oleic acid was also successful, and it gave spherical FePt NCs that had average particle size (APS) of 5.0 ± 1.5 nm. In addition, the surface-modified FePt NCs showed good dispersition into organic solvents. A dispersion in tetrahydrofuran (THF) was stable for at least 3 days. The dried surface-modified FePt NCs were easily oxidized in the atmosphere. This high reactivity to oxygen makes the characterization difficult and, at the same time, may indicate that quite a small amount of Fe NC is included in the reaction products.