bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and enrichment of Ginkgo biloba extract by a continuous chromatography system
Authors: Zhu Jingbo , Cui Weibin , Xiao Wei , Ding Yan , Huang Wenzhe , Tu Pengfei , Wang Yonghua 
Published: March 2018

AbstractIn this study, an effective method was developed for the isolation and enrichment of Ginkgo biloba extract by continuous chromatography system. The adsorption and desorption ratio of flavonoids as main index, the best macroporous resin was screened out from six resins by static adsorption and desorption tests. At the same time the adsorption and desorption parameters were optimized by dynamic adsorption and desorption tests. Under optimal parameters, five operations consisting of loading, washing, desorbing, regenerating, and balancing were integrated across the continuous chromatography system for the purpose of refining 66 L of crude extract solution. The results were as follows, 198.22 g of Ginkgo biloba extracts was produced, which contained 65.83 g of flavonoids and 15.44 g of lactones. The content of flavonoids and lactones increased from 2.76 and 0.72% in the crude extract to 33.21 and 7.79%, with a recovery yield of 91.26 and 81.21%. Methodology validation showed that the proposed method had high stability and reproducibility. Compared with the traditional macroporous resin method, the proposed method had a short processing time and low solvent consumption. Our studies indicated that the newly developed method is an effective procedure for the isolation and enrichment of Ginkgo biloba extract.
Northern bobwhite foraging response to hunting
Authors: McGrath Diana J. , Terhune Theron M. , Martin James A. 
Published: March 2018

ABSTRACTPrey species must consistently balance the need for resource acquisition with the threat of predation. This balance is particularly true for gallinaceous birds, such as the northern bobwhite (Colinus virginianus), which are ground foragers and are often exposed to increased predation risk compared to arboreal foragers. We studied how bobwhites might mitigate the threat of human hunting pressure by altering their foraging strategy. We directly monitored hunting encounters with bobwhites, during October 2014–March 2015, and collected daily movement paths (n = 514) using radio‐telemetry. We performed first‐passage time analysis to infer foraging behavior by calculating bout frequency, area, duration, and timing. We found bobwhites mitigated exposure to human hunters by increasing foraging frequency coupled with a decrease in duration (15.4%) and area (7.1%) in response to hunting pressure. We observed a temporal shift in foraging away from peak hunting hours by 30 minutes when birds were recently exposed to a discharged firearm. Our results imply that hunting game species can disrupt timing of foraging and therefore influence allocation to competing activities such as anti‐predator vigilance. We propose implementing a dynamic harvest management regime that distributes hunting activity temporally and spatially to mitigate high hunting pressure and reduce behavioral effects on bobwhites. Careful planning of hunting activity should reduce its additive effects on natural mortality while improving hunter satisfaction. © 2018 The Wildlife Society.
Improved calculation of the equilibrium magnetization of arterial blood in arterial spin labeling
Authors: Ahlgren André , Wirestam Ronnie , Knutsson Linda , Petersen Esben Thade 
Published: March 2018

PurposeTo propose and assess an improved method for calculating the equilibrium magnetization of arterial blood (
), used for calibration of perfusion estimates in arterial spin labeling.MethodsWhereas standard
calculation is based on dividing a proton density–weighted image by an average brain–blood partition coefficient, the proposed method exploits partial‐volume data to adjust this ratio. The nominator is redefined as the magnetization of perfused tissue, and the denominator is redefined as a weighted sum of tissue‐specific partition coefficients. Perfusion data were acquired with a pseudo‐continuous arterial spin labeling sequence, and partial‐volume data were acquired using a rapid saturation recovery sequence with the same readout module. Results from 7 healthy volunteers were analyzed and compared with the conventional method.ResultsThe proposed method produced improved
homogeneity throughout the brain in all subjects. The mean gray matter perfusion was significantly higher with the proposed method compared with the conventional method: 61.2 versus 56.3 mL/100 g/minute (+8.7%). Although to a lesser degree, the corresponding white matter values were also significantly different: 20.8 versus 22.0 mL/100 g/minute (−5.4%). The spatial and quantitative differences between the 2 methods were similar in all subjects.ConclusionCompared with the conventional approach, the proposed method produced more homogenous
maps, corresponding to a more accurate calibration. The proposed method also yielded significantly different perfusion values across the whole brain, and performed consistently in all subjects. The new
method improves quantitative perfusion estimation with arterial spin labeling, and can therefore be of considerable value in perfusion imaging applications.
Dynamic multivoxel‐localized 31P MRS during plantar flexion exercise with variable knee angle
Authors: Niess Fabian , Fiedler Georg B. , Schmid Albrecht I. , Laistler Elmar , Frass‐Kriegl Roberta , Wolzt Michael , Moser Ewald , Meyerspeer Martin 
Published: March 2018

Exercise studies investigating the metabolic response of calf muscles using 31P MRS are usually performed with a single knee angle. However, during natural movement, the distribution of workload between the main contributors to force, gastrocnemius and soleus is influenced by the knee angle. Hence, it is of interest to measure the respective metabolic response of these muscles to exercise as a function of knee angle using localized spectroscopy.Time‐resolved multivoxel 31P MRS at 7 T was performed simultaneously in gastrocnemius medialis and soleus during rest, plantar flexion exercise and recovery in 12 healthy volunteers. This experiment was conducted with four different knee angles.PCr depletions correlated negatively with knee angle in gastrocnemius medialis, decreasing from 79±14 % (extended leg) to 35±23 %(∼40°), and positively in soleus, increasing from 20±21 % to 36±25 %; differences were significant. Linear correlations were found between knee angle and end‐exercise PCr depletions in gastrocnemius medialis (R2=0.8) and soleus (R2=0.53). PCr recovery times and end‐exercise pH changes that correlated with PCr depletion were consistent with the literature in gastrocnemius medialis and differences between knee angles were significant. These effects were less pronounced in soleus and not significant for comparable PCr depletions. Maximum oxidative capacity calculated for all knee angles was in excellent agreement with the literature and showed no significant changes between different knee angles.In conclusion, these findings confirm that plantar flexion exercise with a straight leg is a suitable paradigm, when data are acquired from gastrocnemius only (using either localized MRS or small surface coils), and that activation of soleus requires the knee to be flexed. The present study comprises a systematic investigation of the effects of the knee angle on metabolic parameters, measured with dynamic multivoxel 31P MRS during muscle exercise and recovery, and the findings should be used in future study design.
Retinoic acid and tracheal occlusion for diaphragmatic hernia treatment in rabbit fetuses
Authors: Delabaere Amélie , Blanchon Loïc , Coste Karen , Clairefond Gael , Belville Corinne , Blanc Pierre , Marceau Geoffroy , Sapin Vincent , Gallot Denis 
Published: March 2018

AbstractIntroductionLung hypoplasia and pulmonary arterial hypertension in congenital diaphragmatic hernia lead to a high perinatal mortality. Although sustained fetoscopic tracheal occlusion (TO) improves lung development, a major side effect is abnormal pneumocyte differentiation. This study evaluated the potential ability of intratracheal retinoic acid (RA) administration to reduce adverse effects of sustained TO in a rabbit model of diaphragmatic hernia.MethodsA left diaphragmatic defect was created on day 23 in time‐dated pregnant rabbits. On day 28, the same rabbits underwent sham surgery or TO, with an injection of empty or RA‐loaded liposomes. On day 30, the fetuses were harvested, and the lungs were processed for histology, immunohistochemistry, and gene expression quantification.ResultsA tracheal RA injection at the time of TO had no effect on the lung‐to‐body‐weight ratio, radial alveolar count or lung connective tissue composition. Retinoic acid plus TO had synergic effects on vascular measurements, proportional medial thickness, and endothelin‐1 receptor type‐A gene expression. The most noticeable effect was recovery of normal pneumocyte differentiation.ConclusionRetinoic acid plus TO prevented abnormal pneumocyte differentiation and seemed to have a beneficial effect on pulmonary vascularization.
Poly‐(pentaerythritol adipate)‐co‐(poly ethylene glycol) Elastomers for the Sustained Release of Paclitaxel
Authors: Navarro Lucila , Minari Roque J. , Ceaglio Natalia , Masin Marianela , Vaillard Santiago E. 
Published: March 2018

ABSTRACTOver the past 10 years poly‐(polyol alkanoate)s elastomers have intensively been investigated due to their extraordinary potential for soft tissue engineering applications. In this work, a family of novel hyperbranched elastomers based on pentaerythritol and adipic acid, modified with PEG of 200 and 400 Da, is synthesized. The polymers are obtained by a simple 2 steps thermal process that avoids the use of toxic catalysts. Noteworthy, elastomers properties can be finely tuned by adjusting the molar ratio of monomers and curing conditions. The elastomers, which are fully characterized by standard methods, show excellent results in the in vitro controlled release of Paclitaxel. Cell culture assays indicate that all materials are able to inhibit lung cancer cell proliferation and that the release of Paclitaxel reduce cancer cell viability, indicating that the elastomers prepared hereby are good candidates for their use as eluting systems in long term cancer treatment. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1199–1209
Electrocatalytically Active Hollow Carbon Nanospheres Derived from PS‐b‐P4VP Micelles
Authors: Cao Shubo , Qu Ting , Li Yayuan , Zhang Ang , Xue Longfei , Zhao Yongbin , Zheng Lirong , Chen Aihua , Shui Jianglan 
Published: March 2018

AbstractA facile method using polystyrene‐b‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) micelles is demonstrated to synthesize N/FeN4‐doped hollow carbon nanospheres (N/FeN4‐CHNS) with high electrocatalytic activity for oxygen reduction reactions (ORRs). Uniform spherical micelles with PS core and P4VP shell are prepared by exposing PS‐b‐P4VP in a mixture of ethanol/tetrahydrofuran. Pyridinic N in shell cooperates with Fe3+ to induce an in situ polymerization of pyrrole. Tuning molecular composition of PS‐b‐P4VP can form hollow carbon spheres with controlled size down to sub‐100 nm that remains challenge using traditional hard template strategies. N/FeN4‐CHNS possesses a series of desirable properties as electrode materials, including easy fabrication, high reproducibility, large surface area, and highly accessible porous surface. This electrocatalyst exhibits excellent ORR activity (onset potential of 0.976 V vs reversible hydrogen electrode (RHE) and half‐wave potential of 0.852 V vs RHE), higher than that of commercial Pt/C (20 wt%) in an alkaline media, and shows a good activity in an acidic media as well. In addition to its higher stability and methanol tolerance than Pt/C in both alkaline and acidic electrolytes, highly competitive single cell performance is achieved in a proton exchange membrane fuel cell. This work provides a general approach to preparing functionalized small hollow nanospheres based on self‐assembly of block copolymers.
Selectable high‐yield recombinant protein production in human cells using a GFP/YFP nanobody affinity support
Authors: Schellenberg Matthew J. , Petrovich Robert M. , Malone Christine C. , Williams R. Scott 
Published: March 2018

AbstractRecombinant protein expression systems that produce high yields of pure proteins and multi‐protein complexes are essential to meet the needs of biologists, biochemists, and structural biologists using X‐ray crystallography and cryo‐electron microscopy. An ideal expression system for recombinant human proteins is cultured human cells where the correct translation and chaperone machinery are present. However, compared to bacterial expression systems, human cell cultures present several technical challenges to their use as an expression system. We developed a method that utilizes a YFP fusion‐tag to generate recombinant proteins using suspension‐cultured HEK293F cells. YFP is a dual‐function tag that enables direct visualization and fluorescence‐based selection of high expressing clones for and rapid purification using a high‐stringency, high‐affinity anti‐GFP/YFP nanobody support. We demonstrate the utility of this system by expressing two large human proteins, TOP2α (340 KDa dimer) and a TOP2β catalytic core (260 KDa dimer). This robustly and reproducibly yields >10 mg/L liter of cell culture using transient expression or 2.5 mg/L using stable expression.
Ionization of tocopherols and tocotrienols in atmospheric pressure chemical ionization
Authors: Bartosińska Ewa , Borsuk‐De Moor Agnieszka , Siluk Danuta , Markuszewski Michał J. , Wiczling Paweł 
Published: March 2018

RationaleTocopherols and tocotrienols are chemical compounds insusceptible to the ionization process under atmospheric pressure conditions. Therefore, the selection of the optimal ion source settings for their quantification requires special attention. The aim of this study was to analyse the influence of the APCI source parameters on the response of tocochromanols and two related compounds.MethodsStandard solutions of target compounds were injected on the high‐performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (HPLC/APCI‐MS/MS) system separately and analysed with 30 randomly selected ion source settings. The obtained responses were modelled by multivariate linear regression with least absolute shrinkage and selection operator. The developed models were used to choose the best APCI conditions.ResultsMultivariate linear models were built for eight tocochromanols, trolox and BHT. The APCI settings derived from the models did not increase the peak areas obtained for T and T3 during the ionization process. Ionization conditions based on models for trolox and BHT improved analytical responses by 12–36% and 4–32%, respectively. The application of the ion source settings optimal for trolox and BHT to tocochromanols did not result in better analytical responses.ConclusionsThe ionization pattern of tocochromanols in the APCI source is problematic and should be further investigated. Modelling methodology for response improvement presented in this study can be applied in similar studies.
Simultaneous determination of seven pesticide residues in soil samples using ultrasound‐assisted dispersive solid‐phase extraction combined with UHPLC–MS/MS
Authors: Guan Jin , Li Dongjing , Guo Yiguang , Shi Shuang , Yan Feng 
Published: March 2018

AbstractA novel and reliable method for the determination of seven pesticide residues (hexaconazole, flutriafol, triadimenol, tebuconazole, diniconazole, fipronil and picoxystrobin) in soil samples was developed by using ultrasound‐assisted dispersive solid‐phase extraction combined with ultra high performance liquid chromatography and tandem mass spectrometry. In this approach, the target analytes were first extracted from the soil samples into acetonitrile, and the ultrasound technique was applied to increase the extraction efficiency. Next, a dispersive solid‐phase extraction purification step was performed by directly adding adsorbents into the extraction solution. The effects of various parameters on the extraction efficiency of the proposed method were investigated and optimized. Under optimum conditions, the calibration curves showed good linearity in the range of 0.25–250 (hexaconazole, diniconazole and tebuconazole), 0.5–500 (flutriafol, triadimenol and fipronil) and 0.05–200 ng g−1 (picoxystrobin) with the correlation coefficients higher than 0.9994. The limits of detection and quantification for the present method were 0.01–0.08 and 0.03–0.25 ng g−1, respectively. The recoveries of the target analytes ranged from 69.5 to 105.9%. The full procedures were applied for the preconcentration and subsequent determination of seven pesticides in four kinds of real soil samples (corn soil, herbs soil, cucumis melo soil and city lawn soil), and satisfactory results were obtained.
Venous and autonomic function in formerly pre‐eclamptic women and controls matched for body mass index
Authors: Heidema W. M. , van Drongelen J. , Spaanderman M. E. A. , Scholten R. R. 
Published: March 2018

ABSTRACTObjectivePrepregnancy reduced plasma volume (PV) increases the risk of subsequent pre‐eclamptic pregnancy. Reduced PV is thought to reflect venous reserve capacity, especially when venous vasculature is constricted and sympathetic tone is elevated. As obesity might affect these variables, and is associated with pre‐eclampsia, increased body weight may underlie these observations. The aim of this study was to determine whether the relationship between reduced venous reserve and pre‐eclampsia is independent of body mass index (BMI).MethodsThis was an observational case–control study in which venous reserve capacity in 30 formerly pre‐eclamptic, but currently non‐pregnant, women divided equally into three groups based on BMI (BMI 19.5–24.9, 25.0–29.9 or ≥ 30.0 kg/m2), was compared with that in 30 healthy parous, non‐pregnant controls. Cases and controls were matched for BMI, age and parity. Venous reserve capacity was quantified by assessing PV and venous compliance (VeC). The autonomic nervous system regulating venous capacitance was evaluated using heart rate (HR) variability analysis, with the women in a resting supine position and during positive head‐up tilt (HUT).ResultsCompared with controls, formerly pre‐eclamptic women had, when in a resting supine position, lower PV (1339 ± 79 vs 1547 ± 139 mL/m2 (P < 0.0001)), lower VeC (0.04 ± 0.02 vs 0.07 ± 0.02 mL/dL/mmHg (P < 0.0001)), higher sympathetic tone (1.9 ± 1.1 vs 1.2 ± 0.7 (P = 0.002)) and lower baroreceptor sensitivity (BRS; 8.7 ± 3.8 vs 19.0 ± 1.7 ms/mmHg (P < 0.0001)). During HUT, women with a history of pre‐eclampsia had less modulatory capacity over VeC and BRS, while HR and sympathetic tone remained consistently higher.ConclusionsWomen with a history of pre‐eclampsia had reduced venous reserve capacity compared with that in BMI‐matched controls. This is reflected by lower PV and VeC, with the autonomic balance being shifted towards sympathetic dominance and lower BRS. This suggests that underlying reduced venous reserve, but not BMI, relates to pre‐eclampsia. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.
High‐throughput measurement of recombination rates and genetic interference in Saccharomyces cerevisiae
Authors: Raffoux Xavier , Bourge Mickael , Dumas Fabrice , Martin Olivier C. , Falque Matthieu 
Published: March 2018

AbstractAllelic recombination owing to meiotic crossovers is a major driver of genome evolution, as well as a key player for the selection of high‐performing genotypes in economically important species. Therefore, we developed a high‐throughput and low‐cost method to measure recombination rates and crossover patterning (including interference) in large populations of the budding yeast Saccharomyces cerevisiae. Recombination and interference were analysed by flow cytometry, which allows time‐consuming steps such as tetrad microdissection or spore growth to be avoided. Moreover, our method can also be used to compare recombination in wild‐type vs. mutant individuals or in different environmental conditions, even if the changes in recombination rates are small. Furthermore, meiotic mutants often present recombination and/or pairing defects affecting spore viability but our method does not involve growth steps and thus avoids filtering out non‐viable spores.
A Generalizable, Data-Driven Approach to Predict Daily Risk ofClostridium difficileInfection at Two Large Academic Health Centers
Authors: Oh Jeeheh , Makar Maggie , Fusco Christopher , McCaffrey Robert , Rao Krishna , Ryan Erin E. , Washer Laraine , West Lauren R. , Young Vincent B. , Guttag John , Hooper David C. , Shenoy Erica S. , Wiens Jenna 
Published: March 2018

OBJECTIVEAn estimated 293,300 healthcare-associated cases ofClostridium difficileinfection (CDI) occur annually in the United States. To date, research has focused on developing risk prediction models for CDI that work well across institutions. However, this one-size-fits-all approach ignores important hospital-specific factors. We focus on a generalizable method for building facility-specific models. We demonstrate the applicability of the approach using electronic health records (EHR) from the University of Michigan Hospitals (UM) and the Massachusetts General Hospital (MGH).METHODSWe utilized EHR data from 191,014 adult admissions to UM and 65,718 adult admissions to MGH. We extracted patient demographics, admission details, patient history, and daily hospitalization details, resulting in 4,836 features from patients at UM and 1,837 from patients at MGH. We used L2 regularized logistic regression to learn the models, and we measured the discriminative performance of the models on held-out data from each hospital.RESULTSUsing the UM and MGH test data, the models achieved area under the receiver operating characteristic curve (AUROC) values of 0.82 (95% confidence interval [CI], 0.80–0.84) and 0.75 ( 95% CI, 0.73–0.78), respectively. Some predictive factors were shared between the 2 models, but many of the top predictive factors differed between facilities.CONCLUSIONA data-driven approach to building models for estimating daily patient risk for CDI was used to build institution-specific models at 2 large hospitals with different patient populations and EHR systems. In contrast to traditional approaches that focus on developing models that apply across hospitals, our generalizable approach yields risk-stratification models tailored to an institution. These hospital-specific models allow for earlier and more accurate identification of high-risk patients and better targeting of infection prevention strategies.Infect Control Hosp Epidemiol2018;39:425–433