bluuebunny/crossref_metadata_2025_split huggingface dataset:
Porcine natriuretic peptide type B (pNPPB) maintains mouse oocyte meiotic arrest via natriuretic peptide receptor 2 (NPR2) in cumulus cells
Authors: Zhang Yu , Hao Xiaoqiong , Xiang Xi , Wei Kaiwen , Xia Guoliang , Zhang Meijia 
Published: February 2014

SUMMARYIn mouse ovarian follicles, the oocyte is maintained in meiotic prophase arrest by natriuretic peptide type C (NPPC) acting via its cognate receptor, natriuretic peptide receptor 2 (NPR2). As there is a marked species difference in the receptor selectivity of the natriuretic peptide family, this study examined the functional effect of other natriuretic peptides, type A (NPPA) and type B (NPPB), acting via NPR2 on mouse‐oocyte meiotic arrest. The results by quantitative, reverse‐transcriptase PCR showed that Npr2 was the predominant natriuretic peptide receptor transcript, and that Npr1 and Npr3 mRNA levels were negligible in cumulus cells isolated from equine chorionic gonadotropin (eCG)‐primed, immature female mice. While NPPA and NPPB from human and rat had no effect on oocyte maturation, porcine NPPB (pNPPB) maintained oocyte meiotic arrest in a dose‐dependent manner. Furthermore, pNPPB‐mediated meiotic arrest and cGMP production could be completely blocked by the NPR2 inhibitor sphingosine‐1‐phosphate (S1P). Neither the NPR1 antagonist anantin or Npr1 knockout had an effect on pNPPB‐mediated meiotic arrest. Thus, pNPPB can functionally maintain mouse‐oocyte meiotic arrest by the receptor NPR2 of cumulus cells. These findings demonstrate that pNPPB may be used as a probe to identify the essential amino acid sequences for activation of NPR2. Mol. Reprod. Dev. 81: ???–???, 2014. © 2014 Wiley Periodicals, Inc.
Accelerated and navigator‐gated look‐locker imaging for cardiac t1 estimation (ANGIE): Development and application to T1 mapping of the right ventricle
Authors: Mehta Bhairav B. , Chen Xiao , Bilchick Kenneth C. , Salerno Michael , Epstein Frederick H. 
Published: February 2014

PurposeTo develop a method for high‐resolution cardiac T1 mapping.MethodsA new method, accelerated and navigator‐gated look‐locker imaging for cardiac T1 estimation (ANGIE), was developed. An adaptive acquisition algorithm that accounts for the interplay between navigator gating and undersampling patterns well‐suited for compressed sensing was used to minimize scan time. Computer simulations, phantom experiments, and imaging of the left ventricle (LV) were used to optimize and evaluate ANGIE. ANGIE's high spatial resolution was demonstrated by T1 mapping of the right ventricle (RV). Comparisons were made to modified Look‐Locker imaging (MOLLI).ResultsRetrospective reconstruction of fully sampled datasets demonstrated the advantages of the adaptive algorithm. For the LV, ANGIE measurements of T1 were in good agreement with MOLLI. For the RV, ANGIE achieved a spatial resolution of 1.2 × 1.2 mm2 with a scan time of 157 ± 53 s per slice, and measured RV T1 values of 980 ± 96 ms versus 1076 ± 157 ms for lower‐resolution MOLLI. ANGIE provided lower intrascan variation in the RV T1 estimate compared with MOLLI (P < 0.05).ConclusionANGIE enables high‐resolution cardiac T1 mapping in clinically reasonable scan times. ANGIE opens the prospect of quantitative T1 mapping of thin cardiovascular structures such as the RV wall. Magn Reson Med 73:150–160, 2015. © 2014 Wiley Periodicals, Inc.
Comparison of myelin water fraction from multiecho T2 decay curve and steady‐state methods
Authors: Zhang Jing , Kolind Shannon H. , Laule Cornelia , MacKay Alex L. 
Published: February 2014

PurposeMyelin water fraction is conventionally measured from the T2 decay curve. Recently, a steady‐state approach entitled multicomponent‐driven equilibrium single pulse observation of T1/T2 (mcDESPOT) was employed for myelin water fraction mapping. However, no direct comparison between the established multiecho T2 relaxation method and mcDESPOT has been performed.MethodsGradient and spin echo (GRASE) acquired T2 decay curve and mcDESPOT measurements were acquired from 10 healthy volunteers using a 3T MRI. We compared myelin water fraction, transmit radio frequency field (B1), and T2's of intra‐ and extracellular water obtained from both methods.ResultsFor all brain regions examined, myelin water fractions from mcDESPOT were significantly higher than those from multiecho GRASE. B1 maps were qualitatively similar between GRASE and mcDESPOT, but multicomponent T2 times were significantly different. To investigate the effect of exchange, mcDESPOT data were analyzed with and without exchange. When exchange was turned off, intra‐ and extracellular T2 times from mcDESPOT were roughly consistent with GRASE results; however, myelin water fractions derived from mcDESPOT were still significantly higher than those derived from GRASE.ConclusionMyelin water fraction values derived from mcDESPOT cannot be considered to be equivalent to those derived from T2 decay curve approaches. Magn Reson Med 73:223–232, 2015. © 2014 Wiley Periodicals, Inc.
Brain high‐energy phosphates and creatine kinase synthesis rate under graded isoflurane anesthesia: An in vivo 31P magnetization transfer study at 11.7 tesla
Authors: Bresnen Andrew , Duong Timothy Q. 
Published: February 2014

PurposeThe creatine kinase rate of metabolic adenosine triphosphate (ATP) synthesis is an important metabolic parameter but is challenging to measure in vivo due to limited signal‐to‐noise ratio and long measurement time.Theory and MethodsThis study reports the implementation of an accelerated 31P Four Angle Saturation Transfer (FAST) method to measure the forward creatine kinase (CK) rate of ATP synthesis. Along with a high‐field scanner (11.7 Tesla) and a small sensitive surface coil, the forward CK rate in the rat brain was measured in ∼5 min.ResultsUnder 1.2% isoflurane, the forward CK rate constant and metabolic flux were, respectively, kf,CK = 0.26 ± 0.02 s−1 and Ff,CK = 70.8 ± 4.6 μmol/g/min. As a demonstration of utility and sensitivity, measurements were made under graded isoflurane. Under 2.0% isoflurane, kf,CK = 0.16 ± 0.02 s−1 and Ff,CK = 41.0 ± 4.2 μmol/g/min, corresponding to a 38% and 42% reduction, respectively, relative to 1.2% isoflurane. By contrast, the ATP and phosphocreatine concentrations were unaltered.ConclusionThis study demonstrated the 31P FAST measurement of creatine kinase rate of ATP synthesis in rat brain with reasonable temporal resolution. Different isoflurane levels commonly used in animal models significantly alter the CK reaction rate but not ATP and phosphocreatine concentrations. Magn Reson Med 73:726–730, 2015. © 2014 Wiley Periodicals, Inc.
A scalable multigrid method for solving indefinite Helmholtz equations with constant wave numbers
Authors: Livshits Ira 
Published: February 2014

SUMMARYMultigrid techniques are applied to two‐dimensional indefinite Helmholtz equations, with a standard geometric approach aided by a special treatment of oscillatory near‐kernel components of the Helmholtz operator. The algorithm is a modification of the wave‐ray method by Brandt and Livshits, 1997. Its biggest difference from the original is a more traditional problem formulation: the Helmholtz equations with standard, in applications, Sommerfeld boundary conditions. The new slimmed wave‐ray solver is less technical, and it is easier to implement. The algorithm is tested for a combination of problems and discretization parameters, and in all experiments with constant wave numbers, it shows stable convergence and scalability, all at computational costs comparable to the ones of the V (1,1) multigrid cycle. While not the main focus of the paper, Helmholtz equations with variable coefficients are considered, and some preliminaries are presented, followed by a discussion of the limited applicability of the method for such problems and the ways to expand it. Also briefly outlined is the potential and plans for a parallel implementation. Copyright © 2014 John Wiley & Sons, Ltd.
Theoretical bounds for algebraic multigrid performance: review and analysis
Authors: MacLachlan Scott P. , Olson Luke N. 
Published: February 2014

SUMMARYAlgebraic multigrid methods continue to grow in robustness as effective solvers for the large and sparse linear systems of equations that arise in many applications. Unlike geometric multigrid approaches, however, the theoretical analysis of algebraic multigrid is less predictive of true performance. Multigrid convergence factors naturally depend on the properties of the relaxation, interpolation, and coarse‐grid correction routines used, yet without the tools of Fourier analysis, optimal and practical bounds for algebraic multigrid are not easily quantified. In this paper, we survey bounds from existing literature, with particular focus on the predictive capabilities of the theory, and provide new results relating existing bounds. We highlight the impact of these theoretical observations through several model problems and discuss the role of theoretical bounds on practical performance. Copyright © 2014 John Wiley & Sons, Ltd.
Reducing the stigma of bariatric surgery: Benefits of providing information about necessary lifestyle changes
Authors: Vartanian Lenny R. , Fardouly Jasmine 
Published: February 2014

ObjectiveThe aim of this study was to determine whether providing information about the lifestyle changes required for an individual to lose weight following bariatric surgery would mitigate the negative judgments of that individual.MethodsIn an experimental design, participants provided their initial impressions of a woman with obesity before learning that she had lost a significant amount of weight through: (1) diet/exercise, (2) surgery, or (3) surgery + diet/exercise. Participants then provided their impressions of the woman after she had lost weight.ResultsFor ratings of laziness, competence, and responsibility for weight loss, the individual who lost weight through surgery was rated most negatively, followed by the individual who lost weight through surgery + diet/exercise, with the individual who lost weight through diet/exercise alone rated as least lazy, most competent, and most responsible for her weight loss. Mediation analyses further showed that group differences in target ratings of laziness/competence were due to perceptions of responsibility for weight loss.ConclusionsProviding information about the lifestyle changes required for losing weight following bariatric surgery can somewhat dampen the negative evaluations of surgery patients. These findings also highlight the importance of perceived effort in judgments of individuals with obesity.
Risk and resilience factors for grade retention in youth with sickle cell disease
Authors: Ladd Rebecca J. , Valrie Cecelia R. , Walcott Christy M. 
Published: February 2014

AbstractBackgroundYouth with sickle cell disease (SCD) are at higher risk for grade retention than healthy peers. This is salient because research suggests grade retention is ineffective and places youth at additional risk for negative outcomes. The aims of the present study were to identify possible risk factors for grade retention in youth with SCD and to examine positive family functioning as a possible resilience factor.ProcedureData were extracted from phase 3 of the Cooperative Study of Sickle Cell Disease, a multisite, longitudinal study of individuals with SCD. Participants were 370 youth, aged 6–16 years, with complete data on history of grade retention. Collected data included demographics, history of grade retention, disease severity factors, evidence of stroke, family functioning, and academic achievement. A logistic regression model predicting grade retention was calculated.ResultsIncreasing age, lower reading achievement, and lower family cohesion were predictive of higher likelihood of grade retention. Also, high family achievement‐orientation moderated the negative effects of increasing age on likelihood of grade retention, such that at increasing levels of family achievement‐orientation, the relationship between age and grade retention decreased.ConclusionsThese findings suggest the need for interventions that promote connectedness and achievement‐orientation in families of youth with SCD. Research is also needed to further explore other possible risk or resilience factors for grade retention in this population, such as school absenteeism. Pediatr Blood Cancer 2014;61:1252–1256. © 2014 Wiley Periodicals, Inc.
PLK1 expression and BI 2536 effects in childhood acute lymphoblastic leukemia
Authors: Oliveira J.C. , Pezuk J.A. , Brassesco M.S. , Morales A.G. , Queiroz R.G.P. , Scrideli C.A. , Tone L.G. 
Published: February 2014

BackgroundPolo‐like kinase 1 (PLK1) is a conserved kinase that mediates various mitotic events. Compelling data have repeatedly demonstrated its upregulation in different neoplasia, being frequently associated with poor prognosis. However, in childhood acute lymphoblastic leukemia (ALL), no studies have yet been conducted.ProcedurePLK1 expression and association with biological features were evaluated in 65 consecutively diagnosed childhood ALL samples by quantitative real‐time PCR. Moreover, the effects of a specific PLK1 inhibitor, BI 2536, was tested against a panel of nine ALL cell lines at nanomolar concentrations (10, 50, 100 nM).ResultsThe mRNA expression of PLK1 showed great variability in pediatric ALL, but no difference was evidenced compared to normal bone marrow. Additionally, no association was found between PLK1 mRNA expression with any clinical or biological features. Alternatively, high mRNA expression of PLK1 was present in ALL cell lines. In vitro treatment with BI 2536 strongly diminished growth, while presenting significant reduction in colony formation capacity and increased apoptosis rates. Moreover, strong G2/M arrest was detected suggesting important impaired proliferation after treatment.ConclusionsPLK1 mRNA expression level is not associated with prognosis in childhood ALL; however, considering the great variability observed in the sample and the in vitro experiments presented herein, BI 2536 treatment might serve as a promising therapeutic to enhance the efficacy of conventional treatment modalities in some childhood ALL cases. Pediatr Blood Cancer 2014;61:1227–1231. © 2014 Wiley Periodicals, Inc.
Medication use in adults living in Brasilia, Brazil: a cross‐sectional, population‐based study
Authors: Galvao Tais F. , Silva Marcus T. , Gross Raz , Pereira Mauricio G. 
Published: February 2014

ABSTRACTPurposeTo assess the prevalence of medicine use in adults of Brasilia and to elucidate the associated factors.MethodsA cross‐sectional study was conducted with adults (18 to 65 years) living in Brasilia, who were selected using a two‐stage probabilistic sampling and interviewed in their home, from February to May 2012. The primary outcome was the use of medicines in the last 7 days. A Poisson regression with robust variance was employed to adjust for covariates following a hierarchical model.ResultsThe study included 1820 individuals (11% losses), 60% of which were women, and the mean age was 37 ± 12.6 years. The prevalence of drug consumption was 35.7% (95% confidence interval [95%CI]: 33.5%–37.9%). Medicine consumption was significantly higher in women (prevalence ratio [PR] = 1.54; 95%CI: 1.28–1.85); unemployed or retired people (PR = 1.35; 95%CI: 1.15–1.59); people with hypertension (PR = 2.33; 95%CI: 2.00–2.71), diabetes (PR = 1.46; 95%CI: 1.22–1.74), depression (PR = 1.32; 95%CI: 1.13–1.53), or other chronic diseases (PR = 1.50; 95%CI: 1.26–1.79); and study participants who had a recent medical consultation (PR = 1.49; 95%CI: 1.29–1.71). Medication use was significantly higher at older ages. The participants obtained about half of the drugs from the Brazilian public health system, but this access was significantly different according to the economic class.ConclusionsMedication use was common among adults living in Brasilia and is associated with sex, age, health conditions, and access to healthcare. Copyright © 2014 John Wiley & Sons, Ltd.
Influence of Regular Physical Activity on Warfarin Dose and Risk of Hemorrhagic Complications
Authors: Shendre Aditi , Beasley Timothy Mark , Brown Todd M. , Hill Charles E. , Arnett Donna K. , Limdi Nita A. 
Published: February 2014

ObjectiveTo determine the influence of regular physical activity on stable warfarin dose and risk of major hemorrhage in patients on chronic anticoagulation therapy.DesignRegular physical activity (maintained over > 80% of visits) was ascertained by self‐report at initiation of warfarin therapy (target international normalized ratio [INR] = 2–3) in 1272 patients, with changes documented at monthly anticoagulation clinic visits in a population‐based prospective cohort. Multi‐variable linear regression and survival analysis, respectively, were used to assess influence on warfarin and risk of hemorrhage.SettingOutpatient anticoagulation clinicParticipants1272 anticoagulated patientsMeasurement and Main ResultsThere were 683 (53.7%) patients who were regularly physically active (≥ 30 min ≥ 3 times/week). Physically active patients required warfarin doses that were 6.9% higher (p=0.006) than in physically inactive patients after controlling for sociodemographic factors, vitamin K intake, clinical factors, and genetic variations.The overall incidence of major hemorrhagic events was 7.6/100 person‐years (p‐yrs, 95% confidence interval [CI] 6.4–8.9) in our population. The incidence was lower for physically active patients (5.6/100 p‐yrs, 95% CI 4.2–7.2) than in inactive patients (10.3/100 p‐yrs, 95% CI 8.2–12.9, p=0.0004). Active patients had a 38% lower risk of hemorrhage (hazard ratio 0.62, 95% CI 0.42–0.98, p=0.03) compared with inactive patients.ConclusionsRegular physical activity is associated with higher warfarin dose requirements and lower risk of hemorrhage. The influence of physical activity on drug response needs to be further explored, and the mechanisms through which it exerts these effects need to be elucidated.
Temperature accelerated life test on commercial concentrator III–V triple‐junction solar cells and reliability analysis as a function of the operating temperature
Authors: Espinet‐González P. , Algora C. , Núñez N. , Orlando V. , Vázquez M. , Bautista J. , Araki K. 
Published: February 2014

AbstractA temperature accelerated life test on commercial concentrator lattice‐matched GaInP/GaInAs/Ge triple‐junction solar cells has been carried out. The acceleration of the aging has been accomplished by subjecting the solar cells at temperatures markedly higher than the nominal working temperature inside a concentrator, and the nominal photo‐current condition (820 X) has been emulated by injecting current in darkness. Three tests at different temperatures have been carried out. The failure distributions across the three test temperatures have been fitted to an Arrhenius–Weibull model. An Arrhenius activation energy of 1.59 eV was determined from the fit. The reliability functions and parameters of these solar cells at two nominal working conditions (80 and 100 °C) have been obtained. In both cases, the instantaneous failure rate function monotonically increases, that is, the failures are of the wear‐out kind. We have also observed that the reliability data are very sensitive to the nominal temperature condition. In fact, at a nominal working condition of 820 X and 80 °C, assuming that the concentration module works 5 h per day, the warranty time obtained for a failure population of 5% has been 113 years. However, for a nominal working condition of 820 X and 100 °C, the warranty time obtained for a failure population of 5% has been 7 years. Therefore, in order to offer a long‐term warranty, the working temperature could be a key factor in the design of the concentration photovoltaic systems. Copyright © 2014 John Wiley & Sons, Ltd.
Synthesis and optical properties of poly(aryl ether ketone)s incorporating porphyrins in the backbones
Authors: Du Yinlong , Zhang Shuling , Jiang Xu , Zhu Kai , Geng Zhi , Fang Yu , Huo Pengfei , Liu Chuan , Song Yinglin , Wang Guibin 
Published: February 2014

ABSTRACTA series of novel soluble poly(aryl ether ketone)s (PAEKs) based on 5,10‐bis(4‐hydroxyphenyl)−15,20‐diphenylporphyrin (cis‐DHTPP), 4,4′‐(hexafluoroisopropylidene) diphenol (6FBPA) and 4,4′‐difluorobenzophenone (DFB) were synthesized and characterized by FT‐IR, 1H‐NMR, UV–vis and fluorescence spectroscopies. The intrinsic photophysical properties of porphyrins were preserved because of the absence of photoinduced electron transfer in the polymer chains. Investigation of the copolymers thermal properties indicated that these polymers had high glass transition temperatures and excellent thermal stabilities. The results of Z‐scan and optical limiting measurements manifested that incorporation of the porphyrin chromophore into the main chain engendered the novel PAEKs with superior nonlinear optical properties and optical limiting function, which could be effectively tuned by varying the molar ratio of porphyrin monomers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1282–1290
An approach to improve the efficiency of polymerization and enhance biological activity of poly(lactide‐co‐ethylene oxide fumarate) hydrogels
Authors: Lee Sherry , Zhong Xia , Ravarian Roya , Valtchev Peter , Dehghani Fariba 
Published: February 2014

ABSTRACTThe synthesis and purification of poly(lactide ethylene oxide fumarate) (PLEOF) involved using organic solvents and triethylamine, an acid scavenger that produces toxic complexes. These issues were addressed by using potassium carbonate as an alternative acid scavenger and CO2 gas expanded solution as a media for reaction. Conducting the reaction at these conditions resulted in reducing the number of stages for purification, enhancing the yield of polymerization by 31%, and increasing the fumarate fraction by 110% compared with conventionally produced polymers. Therefore, the capacity of polymer for crosslinking was significantly promoted that resulted in elevating the compression modulus of hydrogel by 119%. Eliminating the toxic chemical residues and strengthening the mechanical property of PLEOF led to enhancement in primary osteoblast cell proliferation on this hydrogel. The new strategy for the synthesis of PLEOF had paramount impact on the characteristics of this polymer and enhanced its biocompatibility for tissue engineering applications, particularly bone repair. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1291–1299
Carbon fibers prepared from tailored reversible‐addition‐fragmentation transfer copolymerization‐derived poly(acrylonitrile)‐co‐poly(methylmethacrylate)
Authors: Spörl Johanna M. , Ota Antje , Beyer Ronald , Lehr Thomas , Müller Alexandra , Hermanutz Frank , Buchmeiser Michael R. 
Published: February 2014

ABSTRACTReversible‐addition fragmentation‐transfer (RAFT) polymerization of acrylonitrile (AN) was performed with 2‐(2‐cyano‐2‐propyl‐dodecyl)trithiocarbonate as RAFT agent and azobis(isobutyronitrile) as initiator. Linear polyacrylonitrile (Mn = 133,000 g/mol, PDI = 1.34) was prepared within 7 h in 86% isolated yield. High‐yield copolymerization with methyl methacrylate (MMA) was performed and copolymerization parameters were determined according to Kelen and Tüdös at 90 °C in ethylene carbonate yielding rAN = 0.2 and rMMA = 0.42. The molecular weights, polydispersity indices (PDIs), and MMA content of the copolymer were adjusted in a way that precursor fibers could be prepared via wet spinning. These precursor fibers had round cross‐sections and a dense morphology, showing tenacities of 40–50 cN/tex and elastic moduli of 900–1000 cN/tex at a fineness of 1 dtex and an elongation of 13–17%. Precursor fibers were oxidatively stabilized and then carbonized at different temperatures. A maximum tensile strength of 2.5 GPa was reached at 1350 °C. Thermal analysis, infrared and Raman spectroscopy, wide‐angle X‐ray scattering, scanning electron microscopy, and tensile testing were used to characterize the resulting carbon fibers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1322–1333