bluuebunny/crossref_metadata_2025_split huggingface dataset:
Demography of greater prairie‐chickens: Regional variation in vital rates, sensitivity values, and population dynamics
Authors: McNew Lance B. , Gregory Andrew J. , Wisely Samantha M. , Sandercock Brett K. 
Published: March 2012

AbstractIntensification of rangeland management has coincided with population declines among obligate grassland species in the largest remaining tallgrass prairie in North America, although causes of declines remain unknown. We modeled population dynamics and conducted sensitivity analyses from demographic data collected for an obligate grassland bird that is an indicator species for tallgrass prairie, the greater prairie‐chicken (Tympanuchus cupido), during a 4‐year study in east‐central Kansas, USA. We examined components of reproductive effort and success, juvenile survival, and annual adult female survival for 3 populations of prairie‐chickens across an ecological gradient of human landscape alteration and land use. We observed regional differences in reproductive performance, survivorship, and population dynamics. All 3 populations of prairie‐chickens were projected to decline steeply given observed vital rates, but rates of decline differed across a gradient of landscape alteration, with the greatest declines in fragmented landscapes. Elasticity values, variance‐scaled sensitivities, and contribution values from a random‐effects life‐table response experiment all showed that the finite rate of population change was more sensitive to changes in adult survival than other demographic parameters in our declining populations. The rate of population change was also sensitive to nest survival at the most fragmented and least intensively grazed study site; suggesting that patterns of landscape fragmentation and land use may be affecting the relative influences of underlying vital rates on rates of population growth. Our model results indicate that 1) populations of prairie‐chickens in eastern Kansas are unlikely to be viable without gains from immigration, 2) rates of population decline vary among areas under different land management practices, 3) human land‐use patterns may affect the relative influences of vital rates on population trajectories, and 4) anthropogenic effects on population demography may influence the regional life‐history strategies of a short‐lived game bird. © 2012 The Wildlife Society.
Peroxidase‐catalyzed electrochemical assay of hydrogen peroxide: A ping–pong mechanism
Authors: Deyhimi F. , Nami F. 
Published: March 2012

AbstractIn view of the great importance of determination of hydrogen peroxide in many scientific fields and industrial applications and the attractive operational simplicity of potentiometric approach for the enzymatic assay, the kinetics of horseradish peroxidase–catalyzed electrochemical assay of H2O2 was studied in this work at 25°C. All kinetic characteristics were determined by the double reciprocal Lineweaver–Burk and (primary and secondary) double reciprocal Hanes–Woolf plots. The results confirmed that the reaction follows a ping–pong mechanism. The Michaelis–Menten constants for H2O2 and 4‐fluorophenol were Km = 0.081 ± 0.001 mM and K4‐FPm = 0.185 ± 0.002 mM, respectively. The maximum rate was also estimated to be Vmax  = 0.182 ± 0.002 mM min−1 (at 25 ± 0.05°C). © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 699–704, 2012
Kinetic studies of glucose electrocatalytic oxidation on GC/Ni electrode
Authors: Danaee I. , Jafarian M. , Forouzandeh F. , Gobal F. 
Published: March 2012

AbstractNickel‐modified glassy carbon electrode (GC/Ni) prepared by galvanostatic deposition was used for the electrocatalytic oxidation of glucose in alkaline solutions where different electrochemical methods were employed. In cyclic voltammetry studies, in the presence of glucose an increase in the peak current of the oxidation of nickel hydroxide is followed by a decrease in the corresponding cathodic current. This suggests that the oxidation of glucose is being catalyzed through mediated electron transfer across the nickel hydroxide layer comprising nickel ions of various valence states. Under the chronoamperometric regime, the reaction followed a Cottrellian behavior and the diffusion coefficient of glucose was found to be 8 × 10−6 cm2 s−1. A mechanism based on the electrochemical generation of Ni3+‐active sites and their subsequent consumptions by glucose has been discussed, and kinetic parameters have been derived. The heterogeneous rate constants for the oxidation of glucose at the surface of modified electrodes were determined by rotating disk electrode using the Koutecky–Levich plots, which are in agreement with the data obtained by chronoamperometry. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 712–721, 2012
Modeling of Network Formation in Nitroxide‐Mediated Radical Copolymerization of Vinyl/Divinyl Monomers Using a Multifunctional Polymer Molecule Approach
Authors: Hernández‐Ortiz Julio C. , Vivaldo‐Lima Eduardo , Penlidis Alexander 
Published: March 2012

AbstractA mathematical model for the kinetics of copolymerization with crosslinking of vinyl/divinyl monomers in the presence of stable nitroxyl radicals is presented. A reaction scheme considering multifunctional polymer molecules is proposed. The Flory‐Stockmayer theory is used for the post‐gelation period. Average crosslink and cyclization densities are calculated using two different approaches. Good agreement between predicted profiles and experimental data from our and other groups is observed in all cases. Overall monomer concentration, controller/initiator ratio, and crosslinker initial concentration are found to be the governing factors for the development of average crosslink and cyclization densities and therefore for the homogeneity of the resulting polymer network. magnified image
Cytoprotective effects of hesperetin and hesperidin against amyloid β‐induced impairment of glucose transport through downregulation of neuronal autophagy
Authors: Huang Shang‐Ming , Tsai Shin‐Yi , Lin Jer‐An , Wu Chi‐Hao , Yen Gow‐Chin 
Published: March 2012

ScopeThis study investigated whether flavonoids, such as hesperetin and hesperidin, inhibited amyloid β (Aβ)‐impaired glucose utilization through regulating cellular autophagy in insulin‐stimulated neuronal cells.Methods and resultsIn this study, we used a toxic Aβ1‐42 peptide to impair insulin‐stimulated glucose utilization in Neuro‐2A cells, and this study also hypothesized that Aβ‐induced autophagy might be emerging as a key process regulating neuronal glucose uptake. Additionally, hesperetin and hesperidin were used to test the neuroprotective effect against Aβ‐induced impairment of glucose utilization. Our data found that Aβ‐stimulated autophagy activation promoted the phenomenon of impairment of neuronal energy metabolism, including glucose uptake, glucose transporters (GLUTs), and insulin signaling cascades. In this study, confocal images of autophagy punctate further confirmed that downregulation of Aβ‐stimulated autophagy could increase insulin‐stimulated neuronal glucose uptake. Moreover, treatment with hesperetin and hesperidin improved Aβ‐impaired glucose utilization by inhibiting Aβ‐induced autophagy in neuronal cells.ConclusionThese findings suggest that downregulation of autophagy may be one of the approaches to control the impairment of energy metabolism leading to neuronal injury in the early development of Alzheimer's disease, and hesperetin or hesperidin may be a potential agent in the preventing of Alzheimer's disease progression.
The relationship between continence and perineal body tone before and after radical prostatectomy: A pilot study
Authors: Rigatti Lorenzo , Centemero Antonia , Lughezzani Giovanni , Larcher Alessandro , Giraudo Donatella , Scapaticci Emanuele , Sangalli Mattia , Lista Giuliana , Lazzeri Massimo , Montorsi Francesco , Rigatti Patrizio , Guazzoni Giorgio 
Published: March 2012

AbstractIntroductionRecent preliminary studies showed that tonic‐trophic characteristics of the pelvic muscles are related to postoperative male urinary incontinence. The aim of the current study was to test whether perineal body tone (PBT), evaluated using the Beco perineometer (Perineocaliper), is related to urinary continence recovery after robot‐assisted laparoscopic prostatectomy (RALP).Materials and MethodsThe study population consisted of 48 patients who underwent RALP between January and July 2009. Surgical interventions were performed by a single surgeon and patients were evaluated by a single physiotherapist. All patients were taught pelvic floor muscle exercises (PFME). PBT was evaluated in each patient preoperatively, as well 30 days and 3 months after surgery. In addition, patients were evaluated with a 24‐hr pad‐test and the International Consultation on Incontinence‐questionnaire (ICI‐Q).ResultsMean age at surgery was 65.5 years (range 46–63). Twenty‐four patients underwent a bilateral nerve‐sparing procedure (50%). One‐month after surgery, 25 (52.1%) patients were continent while 23 (47.9%) patients were still incontinent. A statistically significant difference in preoperative perineometric measures was observed between continent and incontinent patients (mean 1.36 cm vs. 0.80 cm; P < 0.001). This difference was even more pronounced when comparing postoperative perineometric measures (mean 1.24 cm vs. 0.43 cm; P < 0.001). Evaluation of patients 3 months after surgery showed an increase in perineometric measures (mean increase 0.76 cm). The increase was significantly higher in patients who became continent after 3 months relative to patients who were still incontinent despite PFME (mean perineometric measures 1.45 cm vs. 1.00 cm; P = 0.021).ConclusionsOur results demonstrate that urinary continence recovery is related to PBT recovery. Further studies are needed to confirm whether perineometric measures may be used as a predictive tool for the risk‐stratification of postoperative UI. Neurourol. Urodynam. 31:513–516, 2012. © 2012 Wiley Periodicals, Inc.
Simultaneous Extraction and Separation of Flavonols and Flavones from Chamaecyparis obtusa by Multi‐phase Extraction using an Ionic Liquid‐modified Microsphere Polymer
Authors: Tian Minglei , Bi Wentao , Row Kyung Ho 
Published: March 2012

ABSTRACTIntroductionFlavonols and flavones, especially quercitrin, myricetin and amentoflavone, are the main anti‐bacterial and anti‐cancer compounds in Chamaecyparis obtuse. Multi‐phase extraction is a new method that can extract and separate target compounds simultaneously.ObjectiveAn amino ionic liquid immobilised microsphere polymer was used as a multi‐phase extraction sorbent to extract and separate quercitrin, myricetin and amentoflavone from Chamaecyparis obtusa.MethodologyThe sorbent and Chamaecyparis obtusa powder were packed into a single cartridge. Using a fixed volume of methanol with five repetitions, the target compounds were extracted from the powder to the sorbent. The sorbent was then washed with n‐hexane to remove any interfering species and the target compounds were eluted sequentially using water, methanol and methanol containing 1% acetic acid (vol.).ResultsUnder the optimised conditions, 0.45 mg/g of quercitrin, 0.18 mg/g of myricetin and 0.12 mg/g of amentoflavone from 2.0 g of powder were obtained by multi‐phase extraction using 0.3 g of sorbent.ConclusionThe method described has a low deviation error, requires a small amount of solvent and is highly selective and reproducible. Copyright © 2012 John Wiley & Sons, Ltd.
Use of thiazolidinediones and risk of osteoporotic fracture: disease or drugs?
Authors: Bazelier Marloes T. , Gallagher Arlene M. , van Staa Tjeerd‐Pieter , Cooper Cyrus , Leufkens Hubert G. M. , Vestergaard Peter , de Vries Frank 
Published: March 2012

ABSTRACTPurposeClinical and observational studies suggest that use of thiazolidinediones (TZDs) is associated with an increased fracture risk. In addition, type 2 diabetes mellitus (T2DM) is a risk factor for osteoporotic fracture. Our aim was to estimate fracture risks in TZD users and users of other antidiabetic drugs, classified according to proxies of disease severity.MethodsWe conducted a population‐based cohort study utilizing the Dutch PHARMO database (1998–2008). PHARMO links pharmacy‐dispensing data to the National Hospital Registry. Oral antidiabetic users (n = 123 452) were matched 1:4 by year of birth and sex to non‐users. Cox proportional hazards models were used to estimate hazard ratios (HRs) of fracture in TZD users. We created a proxy indicator for disease severity. The first stage was defined as current use of either a biguanide or a sulfonylureum, the second stage as current use of a biguanide and a sulfonylureum at the same time, the third stage was assigned to patients using TZDs and the fourth stage to patients using insulin.ResultsThe risk of osteoporotic fracture was increased 1.5‐fold (HR 1.49, 95%CI 1.28–1.73) in patients who currently used TZDs (stage 3), and for patients using insulin (stage 4), the risk was increased 1.2‐fold (HR 1.24, 1.14–1.36), as compared with controls. In the first and second stages, risks were lower: HR 1.11 (1.06–1.17) for stage 1 and HR 1.03 (0.96–1.11) for stage 2.ConclusionsWhen observational studies assess risk of fracture in patients with TZDs, the severity of T2DM should be taken into account. Copyright © 2012 John Wiley & Sons, Ltd.
α‐Propargyl amino acid‐derived optically active novel substituted polyacetylenes: Synthesis, secondary structures, and responsiveness to ions
Authors: Sogawa Hiromitsu , Shiotsuki Masashi , Sanda Fumio 
Published: March 2012

AbstractNovel optically active substituted acetylenes HC CCH2CR1(CO2CH3)NHR2 [(S)‐/(R)‐1: R1 = H, R2 = Boc, (S)‐2: R1 = CH3, R2 = Boc, (S)‐3: R1 = H, R2 = Fmoc, (S)‐4: R1 = CH3, R2 = Fmoc (Boc = tert‐butoxycarbonyl, Fmoc = 9‐fluorenylmethoxycarbonyl)] were synthesized from α‐propargylglycine and α‐propargylalanine, and polymerized with a rhodium catalyst to provide the polymers with number‐average molecular weights of 2400–38,900 in good yields. Polarimetric, circular dichroism (CD), and UV–vis spectroscopic analyses indicated that poly[(S)‐1], poly[(R)‐1], and poly[(S)‐4] formed predominantly one‐handed helical structures both in polar and nonpolar solvents. Poly[(S)‐1a] carrying unprotected carboxy groups was obtained by alkaline hydrolysis of poly[(S)‐1], and poly[(S)‐4b] carrying unprotected amino groups was obtained by removal of Fmoc groups of poly[(S)‐4] using piperidine. Poly[(S)‐1a] and poly[(S)‐4b] also exhibited clear CD signals, which were different from those of the precursors, poly[(S)‐1] and poly[(S)‐4]. The solution‐state IR measurement revealed the presence of intramolecular hydrogen bonding between the carbamate groups of poly[(S)‐1] and poly[(S)‐1a]. The plus CD signal of poly[(S)‐1a] turned into minus one on addition of alkali hydroxides and tetrabutylammonium fluoride, accompanying the red‐shift of λmax. The degree of λmax shift became large as the size of cation of the additive. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Hypersonic surface waves in 2D titanium nanostructure on silicon
Authors: Mielcarek Slawomir , Trzaskowska Aleksandra , Graczykowski Bartlomiej , Sarkar Jayanta 
Published: March 2012

AbstractThe non‐destructive method of Brillouin spectroscopy was applied to investigate the vibrations of 2D titanium nanoislands. Simulations realized by the Finite Element Method permitted determination of the dispersion relations of the surface waves propagating in the island structure and silicon substrate as well as the width of the frequency gap for the system studied. 3D maps of unit cell deformation for the structure with nanoislands for individual modes were obtained. The Brillouin experiment is shown as an excellent tool for direct experimental determination of the presence of eigenvibrations and the frequency gap in phononic structures in the GHz range.magnified imageExemplary 3D map of unit cell deformation for the structure with titanium nanoislands of 150 nm.(© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Accelerating convergence in the antisymmetric product of strongly orthogonal geminals method
Authors: Tarumi Moto , Kobayashi Masato , Nakai Hiromi 
Published: March 2012

AbstractAntisymmetric product of strongly orthogonal geminals (APSG) method is a wavefunction theory that can effectively treat the static electron correlation using two‐electron wavefunctions, called geminals. However, the APSG method has the problem of slow convergence in the optimization of the geminal function. In this study, we introduced the direct inversion in the iterative subspace (DIIS) method, for both closed‐ and open‐shell systems, for accelerating its convergence. Two types of error vectors, that is, unitary transformation and orbital gradient, were examined for the DIIS procedure. Numerical assessments revealed that the orbital‐gradient error vector shows better performance than the unitary‐transformation one. © 2012 Wiley Periodicals, Inc.
Application of modified Neumann expansion for analytical evaluation of two‐center, two‐electron integrals over slater‐type orbitals
Authors: Budziński Jan 
Published: March 2012

AbstractA modified form of the Neumann expansion in terms of products of orthogonal polynomials for the inverse interelectronic distance r112 is proposed. This expansion has been applied in order to derive a unified analytical formula for two‐center and two‐electron integrals over Slater‐type orbitals. The results are equivalent to those given recently by Yasui and Saika, but the expansion itself can be used for building up a realistic algorithm for evaluation of three‐ and four‐electron integrals determined by using correlated variational wave functions.
The use of parallel segmented outlet flow columns for enhanced mass spectral sensitivity at high chromatographic flow rates
Authors: Camenzuli Michelle , Goodie Tiffany A. , Bassanese Danielle N. , Francis Paul S. , Barnett Neil W. , Ritchie Harald , LaDine James , Shalliker R. Andrew , Conlan Xavier A. 
Published: March 2012

RATIONALESpeed of analysis is a significant limitation to current high‐performance liquid chromatography/mass spectrometry (HPLC/MS) and ultra‐high‐pressure liquid chromatography (UHPLC)/MS systems. The flow rate limitations of MS detection require a compromise in the chromatographic flow rate, which in turn reduces throughput, and when using modern columns, a reduction in separation efficiency. Commonly, this restriction is combated through the post‐column splitting of flow prior to entry into the mass spectrometer. However, this results in a loss of sensitivity and a loss in efficiency due to the post‐extra column dead volume.METHODSA new chromatographic column format known as 'parallel segmented flow' involves the splitting of eluent flow within the column outlet end fitting, and in this study we present its application on a HPLC electrospray ionization time‐of‐flight mass spectrometer.RESULTSUsing parallel segmented flow, column flow rates as high as 2.5 mL/min were employed in the analysis of amino acids without post‐column splitting to the mass spectrometer. Furthermore, when parallel segmented flow chromatography columns were employed, the sensitivity was more than twice that of conventional systems with post‐column splitting when the same volume of mobile phase was passed through the detector.CONCLUSIONSThese finding suggest that this type of column technology will particularly enhance the capabilities of modern LC/MS enabling both high‐throughput and sensitive mass spectral detection. Copyright © 2012 John Wiley & Sons, Ltd.
Science in discussions: An analysis of the use of science content in socioscientific discussions
Authors: Nielsen Jan Alexis 
Published: March 2012

AbstractThis paper presents a normative pragmatics analysis of students' use of science content in eight socioscientific group discussions about human gene therapy. The specific focus of the paper is on the argumentative role that invocations of science had in the dialectics of the discussions. The analysis suggests that science content occasionally played an informative role in attempts to establish the factual background of parts of the deliberations, but that speakers often invoked science content creatively and selectively in argumentative strategies that aligned with an attempt to frame the issue of the discussion in ways that were favorable for the speaker. The paper aims at explaining how strategies that contained invocations of science worked pragmatically in the dialectical context of the discussions. The findings are discussed in relation to previous findings in the science education community as well as to more general questions pertaining to how science fits into socioscientific discussions in which the arguers deliberate about what to do, not just what is true. © 2012 Wiley Periodicals, Inc. Sci Ed 96:428–456, 2012
Study of the Combined TWIP/TRIP Effect in a High Mn Steel During Cold Rolling
Authors: Ofei Kirk Anguah , Zhao Lie , Sietsma Jilt 
Published: March 2012

AbstractA combined TWIP/TRIP effect has been observed in a high Mn cold rolled steel. The change in the magnetic property of the material with strain due to the austenite‐to‐martensite transformation has been measured and it shows increasing ferromagnetic behavior with strain. The texture development with strain has been analyzed via the Schmid factor for slip and twin systems in the material. The phase transformation has been related to changes occurring in the {110} <001> and {112} <111> texture components as well as to the profiles of XRD peaks at different strain levels.
Prospective Electromyographic Evaluation of Functional Postthyroidectomy Voice and Swallowing Symptoms
Authors: Lombardi Celestino P. , D’Alatri Lucia , Marchese Maria R. , Maccora Daria , Monaco Mauro Lo , De Crea Carmela , Raffaelli Marco 
Published: March 2012

AbstractBackgroundVoice and swallowing symptoms following thyroidectomy in the absence of any demonstration of laryngeal nerves injury are usually considered a functional outcome of uncomplicated operations, mainly related to scar formation and emotional reaction. They could be related to unapparent laryngeal nerve or cricothyroid (CT) muscle injuries detectable only by laryngeal electromyography (LEMG). We correlated such symptoms with LEMG patterns.MethodsA total of 33 consenting patients undergoing total thyroidectomy (TT) were enrolled. Video‐strobolaryngoscopy (VSL), acoustic voice analysis (AVA), and maximum phonation time (MPT) were performed preoperatively and 3 months postoperatively. Subjective evaluation of voice (Voice Impairment Score, or VIS) and swallowing (Swallowing Impairment Score, or SIS) were obtained preoperatively and 1 and 3 months postoperatively. At 1 month postoperatively LEMG was performed examining thyroarytenoid (TA) and CT muscles to evaluate the inferior laryngeal nerve (ILN) and the external branch of the superior laryngeal nerve (EBSLN), respectively.ResultsOne patient experienced transient vocal cord palsy and was excluded. The remaining 32 patients completed the postoperative evaluation. No significant difference was found between preoperative and postoperative AVA and MPT parameters. Mean VIS was significantly worse than preoperatively 1 and 3 months after TT. No significant difference was found between preoperative and postoperative SIS. LEMG evaluation of TA muscle showed decreased voluntary activity and spontaneous fibrillation potentials in one patient. LEMG of the CT muscle did not reveal any sign of EBSLN injury.ConclusionsPatients frequently complain of subjective symptoms early after TT. LEMG demonstrated the absence of subclinical laryngeal nerve injury in all but one patient, confirming their functional nature.