bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three‐dimensional mapping of soil salinity in the southern coastal area of Laizhou Bay, China
Authors: Liu Wenquan , Xu Xingyong , Lu Fang , Cao Jianrong , Li Ping , Fu Tengfei , Chen Guangquan , Su Qiao 
Published: June 2018

AbstractSoil salinization is an important driver of land degradation and has been a major factor inhibiting agricultural production and development in the southern coastal area of Laizhou Bay. In this study, 3‐D and 2‐D geostatistics were respectively used to evaluate the spatial distribution of soil salinity and groundwater total dissolved solids (TDS) and depth. Results showed that soil electrical conductivity differed greatly within the same soil layer, and the difference in average electrical conductivity of different soil layers was relatively small. The mean value of TDS exceeded 3.0 g L−1 and the mean value of groundwater depth was 13.359 m. The geographic distribution showed that the soil salinity gradually decreased from the north to the south horizontally, and the soil salinity showed a bottom accumulation tendency vertically. Over 90% of the study area has TDS values exceeding 1.0 g L−1, and approximately one‐third of the area had a groundwater depth less than 3.0 m. TDS and groundwater depth had good correlations with soil salinity, with coefficients of determination of 0.544 and 0.572, respectively. Changes in vegetation corresponded to changes in soil salinity. Soil salinity gradually decreased perpendicular to coastal lines in tidal flats without vegetative coverage to inland agricultural areas of wheat and vegetables. Soil salinization in the study area is mainly slight and moderate. Reasonable regional management measures are conducive to improving land economic benefits. The results provide a theoretical basis and reference for the partition, improvement, management of saline soil, and support for land degradation control.
Frataxin‐Mediated PINK1–Parkin‐Dependent Mitophagy in Hepatic Steatosis: The Protective Effects of Quercetin
Authors: Liu Peiyi , Lin Hongkun , Xu Yanyan , Zhou Feng , Wang Jing , Liu Jingjing , Zhu Xinhong , Guo Xiaoping , Tang Yuhan , Yao Ping 
Published: June 2018

ScopeNaturally occurring quercetin has been found to induce mitophagy and prevent nonalcoholic fatty liver disease (NAFLD). However, it still remains elusive whether frataxin upregulation by quercetin contributes to the beneficial effect through mitophagy or not.Methods and resultsAdult male C57BL/J mice were fed a high‐fat diet (HFD, 60% of energy from fat) with quercetin (100 mg kg−1 body weight) or not for 10 weeks. Quercetin alleviated HFD‐induced histopathological changes, disorders of lipid metabolism, and mitochondrial damage. Moreover, quercetin blocked mitophagy suppression by HFD based on the increased LC3II, PTEN‐induced putative kinase 1 (PINK1) and Beclin1 expressions, as well as decreased p62 levels. Quercetin also improved the Parkin translocation to mitochondria confirmed by immunofluorescence. Specifically, frataxin was lowered in the liver of HFD‐fed mice or HepG2 cell incubated with oleate/palmitate but restored by quercetin, and quercetin's regulation of frataxin may depend on p53. Furthermore, lentivirus‐mediated stable knockdown of frataxin in HepG2 inhibited PINK1–Parkin‐associated mitophagy and resulted in lipid accumulation. Frataxin was further decreased by free fatty acids in knockdown cells concomitantly with depressed PINK1–Parkin‐associated mitophagy, which was partially normalized by quercetin.ConclusionQuercetin alleviated hepatic steatosis by enhancing frataxin‐mediated PINK1/Parkin‐dependent mitophagy, highlighting a promising preventive strategy and mechanism for NAFLD by quercetin.
Essential Fatty Acids Linoleic Acid and α‐Linolenic Acid Sex‐Dependently Regulate Glucose Homeostasis in Obesity
Authors: Zhuang Pan , Shou Qiyang , Wang Wenqiao , He Lilin , Wang Jun , Chen Jingnan , Zhang Yu , Jiao Jingjing 
Published: June 2018

ScopeTo assess the associations of dietary linoleic acid (LA) and α‐linolenic acid (ALA) with type 2 diabetes (T2D) risk in a population‐based cohort and further explore the mechanism of action in a high‐fat‐diet (HFD) induced obese (DIO) mouse model.Methods and resultsThe occurrence of T2D among 15 100 Chinese adults from China Health and Nutrition Survey (CHNS, 1997–2011) were followed up for a median of 14 years. The relations of ALA and LA intakes with T2D risk were modified by BMI, with significant associations restricted to obese/overweight subjects. Among them, relative risks (95% confidence intervals) comparing extreme quartiles of intakes were 0.55 (0.32–0.93) in men and 0.53 (0.34–0.85) in women for ALA, while 0.71 (0.41–1.16) in men and 0.56 (0.36–0.89) in women for LA. DIO mice were fed with LA‐ or ALA‐enriched HFD (0.2% wt wt−1) for 15 weeks and then significant sex‐dependent changes of gut microbiota were detected. Endotoxemia, systematic and adipose inflammation were relieved in ALA‐fed male and LA‐fed female mice.ConclusionsLong‐term intake of LA (for women) and ALA may have a protective effect on T2D development for obese/overweight subjects through sex‐specific gut microbiota modulation and gut‐adipose axis.
An investigation into the INTRABEAM miniature x‐ray source dosimetry using ionization chamber and radiochromic film measurements
Authors: Watson Peter G. F. , Bekerat Hamed , Papaconstadopoulos Pavlos , Davis Stephen , Seuntjens Jan 
Published: June 2018

PurposeIntraoperative radiotherapy using The INTRABEAM System (Carl Zeiss Meditec AG, Jena, Germany), a miniature low‐energy x‐ray source, has proven to be an effective modality in the treatment of breast cancer. However, some uncertainties remain in its dosimetry. In this work, we investigated the INTRABEAM system dosimetry by performing ionization chamber and radiochromic film measurements of absorbed dose in a water phantom.MethodsIonization chamber measurements were performed with a PTW 34013 parallel‐plate soft x‐ray chamber at source to detector distances of 5 to 30 mm calculated using (a) the dose formula consistent with the TARGIT breast protocol (TARGIT), (b) the formula recommended by the manufacturer (Zeiss), and (c) the recently proposed formalism of Watson et al. (Physics in Medicine & Biology, 2018;63:015016) EBT3 Gafchromic film measurements were made at the same depths in water. To account for the energy dependence of EBT3 film, multiple dose response calibration curves were employed across a range of photon beam qualities relevant to the INTRABEAM spectrum in water.ResultsAt all depths investigated, the TARGIT dose was significantly lower than that measured by the Zeiss and methods, as well as film. These dose differences ranged from 14% to as large as 80%. In general, the doses measured by film, and the Zeiss and methods were in good agreement to within measurement uncertainties (5–6%).ConclusionsThese results suggest that the TARGIT dose underestimates the physical dose to water from the INTRABEAM source. Understanding the correlation between the TARGIT and physical dose is important for any studies wishing to make dosimetric comparisons between the INTRABEAM and other radiation emitting devices.
Interstitial assessment of aggressive prostate cancer by physio‐chemical photoacoustics: An ex vivo study with intact human prostates
Authors: Huang Shengsong , Qin Yu , Chen Yingna , Pan Jing , Xu Chengdang , Wu Denglong , Chao Wan‐Yu , Wei John T. , Tomlins Scott A. , Wang Xueding , Fowlkes J. Brian , Carson Paul L. , Cheng Qian , Xu Guan 
Published: June 2018

PurposeTransrectal ultrasound (TRUS)‐guided biopsy is the standard procedure for evaluating the presence and aggressiveness of prostate cancer. TRUS biopsy involves tissue removal, and suffers from low core yield as well as high false negative rate. A less invasive and more accurate diagnostic procedure for prostate cancer is therefore highly desired. Combining the optical sensitivity and ultrasonic resolution to resolve the spatial distribution of the major molecular components in tissue, photoacoustic (PA) technology could be an alternative approach for the diagnosis of prostate cancer. The purpose of this study was to examine the feasibility of identifying aggressive prostate cancer using interstitial PA measurements.MethodsSeventeen patients with prebiopsy magnetic resonance imaging (MRI), TRUS biopsies, and planned prostatectomies were enrolled in this study. The interstitial PA measurements were achieved using our recently developed needle PA probe, which was inserted into the ex vivo prostates in the fashion of a biopsy needle. A total of 70 interstitial PA measurements were acquired. The PA measurements were quantified by a previously established PA physio‐chemical analysis (PAPCA) method. The histology has confirmed the nonaggressive and aggressive cancerous conditions at the insertion locations. The diagnostic accuracy was also compared to that provided by the prebiopsy MRI.ResultsThe quantitative study shows significant differences between the individual parameters of the nonaggressive and the aggressive cancerous regions (P < 0.005). Multivariate analysis of the quantitative features achieved a diagnostic accuracy of 78.6% for differentiating nonaggressive and aggressive prostate cancer tissues.ConclusionsThe proposed procedure has shown promises in the diagnosis of aggressive prostate cancer.
A phase field model for stress‐based evolution of load‐bearing structures
Authors: Muench I. , Gierden C. , Wagner W. 
Published: June 2018

SummaryWe present a continuum‐type optimality algorithm for the evolution of load‐bearing solid structures with linear elastic material. The objective of our model is to generate structures with help of a sensitivity function accounting for equivalent stress. Similar to Evolutionary Structural Optimization, a threshold of equivalent stress is evaluated. However, we do not consider a material rejection ratio. The evolution process is governed by an Allen‐Cahn equation in the context of phase field modeling. The steady state of phase transition is the final geometry of the structure. The model accounts for the desired filling level, geometry of the design space, static loadings, and boundary conditions. Our variational approach drops conservation of mass and couples density as well as stiffness of the continuum by a sophisticated function to the phase field variable. Continuous regions of voids and material evolve from the initial state of homogeneously distributed material. The complexity of evolving structures depends on two numerical parameters, which we discuss in several examples.
An optimization‐based phase‐field method for continuous‐discontinuous crack propagation
Authors: Geelen Rudy J. M. , Liu Yingjie , Dolbow John E. , Rodríguez-Ferran Antonio 
Published: June 2018

SummaryA new continuous‐discontinuous strategy for the computational modeling of crack propagation within the context of phase‐field models of fracture is presented. The method is designed to introduce and update a sharp crack surface within an evolving damage band and to enhance the kinematics of the finite element approximation accordingly. The proposed approach relies on three key elements. First, we propose the use of a crack length functional to provide a trigger for initiating a continuous to discontinuous transition. Next, the crack path identification is addressed by introducing the concept of an auxiliary damage field that varies with an extension of the sharp crack surface. The sharp crack surface is extended through an optimization algorithm, in which the difference between the auxiliary field and the actual damage field stemming from the phase‐field framework is minimized. Finally, a strong discontinuity is inserted in the wake of the diffuse crack tip with the extended finite element method, completing the continuous to discontinuous transition. Several benchmark problems in two‐dimensional quasi‐static fracture mechanics are presented to demonstrate the accuracy and robustness of the method.
Interfering effect of maternal cell contamination on invasive prenatal molecular genetic testing
Authors: Koczok Katalin , Gombos Éva , Madar László , Török Olga , Balogh István 
Published: June 2018

What is already known about this topic?

Analytical sensitivity of the studied molecular genetic methods such as Sanger DNA sequencing, multiplex ligation‐dependent probe amplification, and next‐generation sequencing has been studied previously in relation to somatic mosaicism testing.
What does this study add?

We determine significant maternal cell contamination levels for these molecular genetic techniques in a comprehensive way and also evaluate previously published data in the context of maternal cell contamination and prenatal molecular testing.
Variability of urban surface temperatures and implications for aerodynamic energy exchange in unstable conditions
Authors: Crawford Ben , Grimmond Sue B. , Gabey Andrew , Marconcini Mattia , Ward Helen C. , Kent Christoph W. 
Published: June 2018

Sensible heat flux (QH) is a critical driver of surface and boundary layer meteorological processes, especially in urban areas. Aerodynamic resistance methods (ARM) for modelling QH are promising because, in principle, all that is needed is surface temperature (T0), air temperature (TA) and an aerodynamic resistance term (rH). There are significant challenges in urban areas, however, due to uncertainties in satellite‐derived land surface temperatures (LST), logistical challenges in obtaining high‐resolution air temperatures, and a limited understanding of spatial and temporal variability of rH and associated variables (e.g. thermal roughness length). This work uses an extensive LST dataset covering 6 years (2011–2016) in central London and a long‐term in situ observation network to analyse the variability of LST and rH variables. Results show that LST is spatially correlated with building and vegetation land cover with coherent thermal structures at length scales less than 500–1,000 m. Additionally, satellite‐observed LST varies with average building height (up to 10% cooler in areas with tall buildings). The rH term and associated variables are observed to vary on daily and seasonal cycles, and findings are used to model QH using five variations of an ARM‐based approach on a 100 m pixel basis. Modelled QH is compared to observations from three scintillometer paths and an eddy covariance flux tower. We find generally good agreement between observations and models, although there is uncertainty in all methods (mean absolute error ranges from 58.1–129.3 W/m2) due to the challenges involved in determining high‐resolution meteorological and surface inputs, particularly LST and friction velocity (u*). Additional complexity in evaluating modelled QH arises from anthropogenic heat sources: long‐term tower‐based observations show that TA and the radiometer‐derived T0 are warmer during working weekdays than non‐working days (up to 0.7 °C) and that there is an observed lag (2–3 hr) between energy consumption and the observed warming and modelled QH.
Characteristics of monsoonal precipitating cloud systems over the Indian subcontinent derived from weather radar data
Authors: Sindhu Kapil Dev , Bhat G. S. 
Published: June 2018

The convective area within a mesoscale convective system (MCS) contains intense convective cells or storms which themselves could be made of a single cumulonimbus cloud or several of them joined together. Interconnection between MCS evolution and storms has not been reported previously. We address this gap area by using the Doppler Weather Radar (DWR) data collected at four stations in India during the summer monsoon season of 2013. The four DWR locations selected have different climates ranging from coastal to semi‐arid. Storm is defined as a set of contiguous radar pixels in three‐dimensional space with a reflectivity threshold of 30 dBZ and the threshold criterion is satisfied in a volume of at least 50 km3. Monsoonal MCSs contain a few to more than 20 storms depending on geographic location and MCS life stage. The average area of storms ranges from 13 to 170 km2 while storm heights mostly lie between 6 and 10 km. The growth stage of an MCS is characterized by a rapid increase in the number of storms, while their number and average area decrease in the dissipation stage. Storms occupy 30–70% of the convective area within an MCS and contribute 90–97% of the convective precipitation at any given instant. Thus, a few to several cumulonimbus clouds grouped together in a contiguous manner matter most for convective precipitation, making storm scale an important scale in the hierarchy of scales in tropical deep convective cloud systems. This has implications for cumulus parametrization as well as planning satellite payloads for observing precipitation.
Characterization of in vitro metabolites of three tetrahydroprotoberberine alkaloids in rat liver S9 by high‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry
Authors: Lin Li , Liu Xiu‐Bin , Zhou Qiao‐Yun , Liu Sha‐Sha , Zuo Meng‐Ting , Zeng Jian‐Guo , Liu Zhao‐Ying 
Published: June 2018

RationaleTetrahydroberberine (THB), tetrahydrocoptisine (THCP) and tetrahydrocolumbamine (THCB) belong to the tetrahydroprotoberberine (THPB) alkaloids. Most of them have been extensively studied because of their pharmacological activities such as anti‐hypertension, anti‐arrhythmia, antimicrobial activity and antioxidant. However, limited information on the pharmacokinetics and metabolism of the three alkaloids has been reported. The purpose of this study was to investigate the in vitro metabolism of THB, THCP and THCB in rat liver S9 by using a rapid and accurate high‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (HPLC/QqTOF‐MS) method.MethodsThe incubation mixture was processed with 15% trichloroacetic acid. Chromatographic separation of the three THPB alkaloids and their metabolites was achieved by HPLC/QqTOF‐MS and accurate mass measurements of metabolites were automatically performed through data‐dependent acquisition in only a 30‐min analysis. The detailed structural elucidations of these metabolites were performed by comparing the changes in their accurate molecular masses, elemental compositions and product ions with those of the parent drug.ResultsFive, five and four metabolites of THB, THCP and THCB were identified in rat liver S9, respectively. The results show that O‐demethylenation of the 9,10‐vicinal methoxyl group was the main metabolic pathway of THB and THCB and that demethylenation of the two methylenedioxy groups was the main metabolic pathway of THCP. In addition, minor oxidation and methylation reactions could occur for these alkaloids in rat liver S9.ConclusionsThis was the first investigation of the in vitro metabolism of THB, THCP and THCB in rat liver S9 by using a sensitive and accurate HPLC/QqTOF‐MS method. The tentatively proposed metabolic pathways of the three alkaloids will provide a basis for further studies of the in vivo metabolism of the three compounds in animals and humans.
Evaluation of lipid peroxidation by the analysis of volatile aldehydes in the headspace of synthetic membranes using selected ion flow tube mass spectrometry
Authors: Shestivska Violetta , Olšinová Marie , Sovová Kristýna , Kubišta Jiří , Smith David , Cebecauer Marek , Španěl Patrik 
Published: June 2018

RationaleOxidative stress of cell membranes leads to a number of pathological processes associated with some diseases and is accompanied by the release of volatile aldehydes, which potentially can be used as biomarkers. Thus, the aim was to investigate peroxidation of defined synthetic membranes by direct quantitative analysis of volatile aldehydes.MethodsThe concentration spectra of volatile compounds present in the headspace of synthetic membranes under peroxidation stress and following mechanical stress due to sonication were obtained using solid‐phase microextraction (SPME) in combination with gas chromatography/mass spectrometry (SPME‐GC/MS) and selected ion flow tube mass spectrometry (SIFT‐MS). The focus was on the direct, real‐time quantification of volatile aldehydes. In addition, the total aldehydes in the aqueous membrane suspensions were quantified using the thiobarbituric acid reactive substances (TBARS) method.ResultsPropanal, butanal, pentanal, hexanal, heptanal and malondialdehyde were detected and quantified in the humid headspace of the media containing the synthetic membranes following peroxidation. The composition and concentration of these saturated aldehydes strongly depend on the representation of unsaturated fatty acids in the liposomes. Some protective effect of cholesterol was observed especially for membranes peroxidised by Fenton reagents and after application of a mechanical stress.ConclusionsThis study demonstrates that peroxidation of model synthetic membranes in vitro can be tracked in real time using direct quantification by SIFT‐MS of several specific aldehydes in the headspace of the membrane suspensions. Cholesterol plays an important role in retaining membrane structure and can indirectly protect membranes from lipid peroxidation.
Presynaptic GCaMP expression decreases vesicle release probability at the calyx of Held
Authors: Singh Mahendra , Lujan Brendan , Renden Robert 
Published: June 2018

AbstractSynaptic vesicle (SV) exocytosis is intimately dependent on free local Ca2+ near active zones. Genetically encoded calcium indicators (GECIs) have become an indispensable tool to monitor calcium dynamics during physiological responses, and they are widely used as a proxy to monitor activity in neuronal ensembles and at synaptic terminals. However, GECIs’ ability to bind Ca2+ at physiologically relevant concentration makes them strong candidates to affect calcium homeostasis and alter synaptic transmission by exogenously increasing Ca2+ buffering. In the present study, we show that genetically expressed GCaMP6m modulates SV release probability at the mouse calyx of Held synapse. GCaMP6m expression for approximately three weeks decreased initial SV release for both low‐frequency stimulation and high‐frequency stimulation trains, and slowed presynaptic short‐term depression. However, GCaMP6m does not affect quantal events during spontaneous activity at this synapse. This study emphasizes the careful use of GECIs as monitors of neuronal activity and inspects the role of these transgenic indicators which may alter calcium‐dependent physiological responses.