bluuebunny/crossref_metadata_2025_split huggingface dataset:
Osteocytes Acidify Their Microenvironment in Response to PTHrP In Vitro and in Lactating Mice In Vivo
Authors: Jähn Katharina , Kelkar Shilpa , Zhao Hong , Xie Yixia , Tiede-Lewis LeAnn M , Dusevich Vladimir , Dallas Sarah L , Bonewald Lynda F 
Published: May 2017

ABSTRACT

Osteocytes appear to mobilize calcium within minutes in response to PTH injections; we have previously shown that osteocytes remove their perilacunar matrix during lactation through activation of the PTH type 1 receptor. Mechanisms utilized by osteocytes to mobilize calcium are unknown but we hypothesized that the molecular components may be similar to those used by osteoclasts. Here we show, using IDG-SW3 cells that ATP6V0D2, an essential component of vacuolar ATPase in osteoclasts, and other genes associated with osteoclastic bone resorption, increase with osteoblast to osteocyte differentiation. Furthermore, PTHrP increases ATP6V0D2 expression and induces proton generation by primary osteocytes, which is blocked by bafilomycin, a vacuolar ATPase inhibitor. These in vitro proton measurements raised the question of osteocyte viability in an acidic environment. Interestingly, osteocytes, showed enhanced viability at pH as low as 5 compared to osteoblasts and fibroblasts in vitro. To study in vivo acidification by osteocytes, virgin and lactating CD1 mice on a low calcium diet were injected with the pH indicator dye, acridine orange, and their osteocyte lacuno-canalicular system imaged by confocal microscopy. Lower pH was observed in lactating compared to virgin animals. In addition, a novel transgenic mouse line with a topaz variant of green fluorescent protein (GFPtpz)-tagged collagen α2(I) chain was used. Instead of the expected reduction in GFP-fluorescence only in the perilacunar matrix, reduced fluorescence was observed in the entire bone matrix of lactating mice. Based on our experiments showing quenching of GFP in vitro, we propose that the observed reduction in GFP fluorescence in lactating mice is due to quenching of GFP by the acidic pH generated by osteocytes. Together these findings provide novel mechanistic insight into how osteocytes remove calcium from their perilacunar/pericanalicular matrices through active acidification of their microenvironment and show that osteocytes, like osteoclasts, are resistant to the negative effects of acid on viability. © 2017 American Society for Bone and Mineral Research.
Comparison of fast acquisition strategies in whole‐heart four‐dimensional flow cardiac MR: Two‐center, 1.5 Tesla, phantom and in vivo validation study
Authors: Garg Pankaj , Westenberg Jos J.M. , van den Boogaard Pieter J. , Swoboda Peter P. , Aziz Rahoz , Foley James R.J. , Fent Graham J. , Tyl F.G.J. , Coratella L. , ElBaz Mohammed S.M. , van der Geest R.J. , Higgins David M. , Greenwood John P. , Plein Sven 
Published: May 2017

PurposeTo validate three widely‐used acceleration methods in four‐dimensional (4D) flow cardiac MR; segmented 4D‐spoiled‐gradient‐echo (4D‐SPGR), 4D‐echo‐planar‐imaging (4D‐EPI), and 4D‐k‐t Broad‐use Linear Acquisition Speed‐up Technique (4D‐k‐t BLAST).Materials and MethodsAcceleration methods were investigated in static/pulsatile phantoms and 25 volunteers on 1.5 Tesla MR systems. In phantoms, flow was quantified by 2D phase‐contrast (PC), the three 4D flow methods and the time‐beaker flow measurements. The later was used as the reference method. Peak velocity and flow assessment was done by means of all sequences. For peak velocity assessment 2D PC was used as the reference method. For flow assessment, consistency between mitral inflow and aortic outflow was investigated for all pulse‐sequences. Visual grading of image quality/artifacts was performed on a four‐point‐scale (0 = no artifacts; 3 = nonevaluable).ResultsFor the pulsatile phantom experiments, the mean error for 2D PC = 1.0 ± 1.1%, 4D‐SPGR = 4.9 ± 1.3%, 4D‐EPI = 7.6 ± 1.3% and 4D‐k‐t BLAST = 4.4 ± 1.9%. In vivo, acquisition time was shortest for 4D‐EPI (4D‐EPI = 8 ± 2 min versus 4D‐SPGR = 9 ± 3 min, P < 0.05 and 4D‐k‐t BLAST = 9 ± 3 min, P = 0.29). 4D‐EPI and 4D‐k‐t BLAST had minimal artifacts, while for 4D‐SPGR, 40% of aortic valve/mitral valve (AV/MV) assessments scored 3 (nonevaluable). Peak velocity assessment using 4D‐EPI demonstrated best correlation to 2D PC (AV:r = 0.78, P < 0.001; MV:r = 0.71, P < 0.001). Coefficient of variability (CV) for net forward flow (NFF) volume was least for 4D‐EPI (7%) (2D PC:11%, 4D‐SPGR: 29%, 4D‐k‐t BLAST: 30%, respectively).ConclusionIn phantom, all 4D flow techniques demonstrated mean error of less than 8%. 4D‐EPI demonstrated the least susceptibility to artifacts, good image quality, modest agreement with the current reference standard for peak intra‐cardiac velocities and the highest consistency of intra‐cardiac flow quantifications.Level of Evidence: 1Technical Efficacy: Stage 2J. Magn. Reson. Imaging 2018;47:272–281.
Interdecadal variation of tropical cyclone genesis frequency in late season over the western North Pacific
Authors: Choi Jae‐Won , Cha Yumi , Kim Taeyun , Kim Hae‐Dong 
Published: May 2017

ABSTRACTThis study analysed the time series of tropical cyclone (TC) frequency during October–December (OND) for 32 years (1980–2011). There was a strong decreasing trend of TCs until recently, and the TC sharply decreased from 1996 after the statistical change‐point analysis was applied to this time series. To investigate the cause of such recent decrease in TC genesis frequency, the differences (TC activity and its relation to large‐scale environments, and others) between the mean of the period from 1996 to 2011 and the mean of the period from 1980 to 1995 were analysed. TCs during the period 1996–2011 mainly occurred in the western region of tropical western North Pacific (TWNP), whereas during the 1980–1995 period they mainly occurred in the eastern region of TWNP. In the analysis of differences periods in the 850 hPa and 500 hPa stream flows between the two periods, an anomalous huge anticyclone existed from the north Pacific to the TWNP, and an anomalous huge cyclone existed to the west of 125°E including the East Asian continent. In other words, this is a typical low‐west‐high‐east pressure system that appears in East Asia during summer, and this anomalous pressure system pattern caused the low TC genesis frequency during the 1996–2011 period. The low‐west‐high‐east anomalous pressure system pattern which has been strengthened recently in East Asia suggests that the East Asian winter monsoon (EAWM) has weakened during the 1996–2011 period. As a result, the amount of snow depth decreased in many areas of the East Asian continent except for the North China and the ground heat net flux also increased in many areas. This weakening of the EAWM strengthened the anomalous huge anticyclone in the TWNP as well as in the central North Pacific, which caused the low TC genesis frequency during the OND in recent years.
Quantitative Analysis of Hepatic Toxicity in Rats Induced by Inhalable Silica Nanoparticles Using Acoustic Radiation Force Imaging
Authors: Cao Wen , Zhou Yajing , Niu Yingmei , Zhu Xiaoli , Song Yuguo , Guo Ruijun 
Published: May 2017

ObjectivesThe purposes of this study were to verify whether inhalable silicon dioxide (SiO2) nanoparticles could induce hepatic injury and to investigate the relationship between the exposure time and SiO2 nanoparticle dosage by using acoustic radiation force impulse imaging (ARFI).MethodsA total of 72 rats were randomly separated into 9 groups with 8 in each: blank control group, 0.9% normal saline group, polyacrylate (PPE) group, 25%, 50%, and 100% SiO2 groups, and 25%, 50%, and 100% SiO2/PPE groups with inhaled SiO2 nanoparticle concentrations similar to the SiO2 groups. After successful modeling and design, the hepatic shear wave velocity (SWV) values of the 9 groups were obtained on days 3, 7, 14, 21, and 28 by using ARFI, and the intragroup and intergroups differences in the SWVs were compared. The serum alanine aminotransferase (ALT) and aspartate aminotransferase were tested and compared on day 28. Hepatic tissues were collected for histologic observation on day 28.ResultsThe pathologic results verified that inhalable SiO2 nanoparticles could induce hepatic injury. Compared with the control group, the hepatic SWV and serum ALT values in the SiO2 groups and SiO2/PPE groups were elevated (P < .05). The dosage and exposure time of SiO2 played a key role in the elevation of the SWV in the SiO2 and SiO2/PPE groups. The correlation between the ALT level and SWV was significant on day 28 (P < .05).ConclusionsInhalable SiO2 nanoparticles and SiO2/PPE were able to induce hepatic injury in rats. Using ARFI to evaluate hepatic toxicity induced by SiO2 nanoparticles was effective in this study.
Qualitative Slow Blood Flow in Lower Extremity Deep Veins on Doppler Sonography: Quantitative Assessment and Preliminary Evaluation of Correlation With Subsequent Deep Venous Thrombosis Development in a Tertiary Care Oncology Center
Authors: Jensen Corey T. , Chahin Antoun , Amin Veral D. , Khalaf Ahmed M. , Elsayes Khaled M. , Wagner‐Bartak Nicolaus , Zhao Bo , Zhou Shouhao , Bedi Deepak G. 
Published: May 2017

ObjectivesTo determine whether the qualitative sonographic appearance of slow deep venous flow in the lower extremities correlates with quantitative slow flow and an increased risk of deep venous thrombosis (DVT) in oncology patients.MethodsIn this Institutional Review Board–approved retrospective study, we reviewed lower extremity venous Doppler sonographic examinations of 975 consecutive patients: 482 with slow flow and 493 with normal flow. The subjective slow venous flow and absence of initial DVT were confirmed by 2 radiologists. Peak velocities were recorded at 3 levels. Each patient was followed for DVT development. The associations between DVT and the presence of slow venous flow were examined by the Fisher exact test; a 2‐sample t test was used for peak velocity and DVT group comparisons. The optimal cutoff peak velocity for correlation with the radiologists' perceived slow flow was determined by the Youden index.ResultsDeep venous thrombosis development in the slow‐flow group (21 of 482 [4.36%]) was almost doubled compared with patients who had normal flow (11 of 493 [2.23%]; P = .0456). Measured peak venous velocities were lower in the slow–venous flow group (P < .001). Patients with subsequent DVT did not have a significant difference in venous velocities compared with their respective patient groups. The sum of 3 venous level velocities resulted in the best cutoff for dichotomizing groups into normal versus slow venous flow.ConclusionsQualitative slow venous flow in the lower extremities on Doppler sonography accurately correlates with quantitatively slower flow, and this preliminary evaluation suggests an associated mildly increased rate of subsequent DVT development in oncology patients.
A terrain‐based weighted random forests method for radar quantitative precipitation estimation
Authors: Yang Xuebing , Kuang Qiuming , Zhang Wensheng , Zhang Guoping 
Published: May 2017

ABSTRACTWhile weather radar is widely used for quantitative precipitation estimation (QPE) in China and many other countries, the performance of radar QPE is unsatisfactory. A major reason for inaccurate radar QPE is the application of conventional Z–R relationships. In this study the entire vertical profile of reflectivity (VPR) is taken into consideration and a new relationship converting the VPR to rainfall rate is developed. The new relationship is obtained by a proposed terrain‐based weighted random forests (TWRF) method. The TWRF method regards 21 levels of constant altitude plan position indicator reflectivity (from 1 to 18 km) as features. The method consists of two parts: the first is to obtain subregions based on terrain, and the second is to refine the classical random forests method by computing feature weights based on correlation co‐efficients between features and rainfall rate. Radar QPE based on the TWRF method was tested within the 45–100 km range of the radar in Hangzhou, China, on rainfall events in 2014. The proposed method showed improved performance for all verification scores over the Z–R relationship and the classical random forests method. Use of the entire VPR and the terrain‐based study proved to be effective in this example. Experimental results indicate that the proposed TWRF method can improve the accuracy of radar QPE compared to an independent network of rain gauges.
Super‐resolution intracranial quiescent interval slice‐selective magnetic resonance angiography
Authors: Koktzoglou Ioannis , Edelman Robert R. 
Published: May 2017

PurposeTo evaluate the combination of nonenhanced quiescent‐interval slice‐selective (QISS) magnetic resonance angiography (MRA) with super‐resolution reconstruction for portraying the intracranial arteries.MethodsThe intracranial arteries of seven volunteers were imaged at 3T using QISS MRA acquired with a flow‐compensated fast low‐angle shot (FLASH) readout and thin overlapping slices. The impacts of super‐resolution reconstruction and various acquisition parameters on the delineation of intracranial arteries were quantified using four metrics: arterial‐to‐background contrast‐to‐noise ratio (CNR), arterial‐to‐background contrast, arterial sharpness, and arterial full‐width‐at‐half‐maximum (FWHM). Three‐dimensional time‐of‐flight (TOF) MRA was also acquired.ResultsFor similar voxel sizes, QISS MRA displayed the intracranial arteries with an arterial‐to‐background contrast that exceeded 3D TOF MRA by 59–84%, depending on the k‐space sampling trajectory (P < 0.001). Super‐resolution reconstruction improved CNR, contrast, and sharpness, while reducing arterial FWHM (P < 0.001). Cardiac triggering provided minimal benefits, while Cartesian sampling provided higher CNR than radial sampling for multishot QISS (P < 0.05). Scan time for a complete intracranial MRA was <90 s using an ungated single‐shot QISS acquisition.ConclusionThin, overlapping‐slice QISS leveraging super‐resolution reconstruction is a flexible approach for intracranial MRA that provides competitive image quality to standard‐of‐care 3D TOF, with the potential for reduced sensitivity to in‐plane flow saturation and motion artifacts. Magn Reson Med 79:683–691, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Multispectral diffusion‐weighted imaging near metal implants
Authors: Koch Kevin M. , Bhave Sampada , Gaddipati Ajeet , Hargreaves Brian A. , Gui Dawei , Peters Robert , Bedi Meena , Mannem Rajeev , Kaushik S. Sivaram 
Published: May 2017

PurposeThe need for diffusion‐weighted‐imaging (DWI) near metallic implants is becoming increasingly relevant for a variety of clinical diagnostic applications. Conventional DWI methods are significantly hindered by metal‐induced image artifacts. A novel approach relying on multispectral susceptibility artifact reduction techniques is presented to address this unmet need.MethodsDWI near metal implants is achieved through a combination of several advanced MRI acquisition technologies. Previously described approaches to Carr–Purcell–Meiboom–Gill spin‐echo train DWI sequences using the periodically rotated overlapping parallel lines with enhanced reconstruction are combined with multispectral‐imaging metal artifact reduction principles to provide DWI with substantially reduced artifact levels. The presented methods are applied to limited sets of slices over areas of sarcoma risk near six implanted devices.ResultsUsing the presented methods, DWI assessment without bulk image distortions is demonstrated in the immediate vicinity of metallic interfaces. In one subject, the apparent diffusion coefficient was reduced in a region of suspected sarcoma directly adjacent to fixation hardware.ConclusionsAn initial demonstration of minimal‐artifact multispectral DWI in the near vicinity of metallic hardware is described and successfully demonstrated on clinical subjects. Magn Reson Med 79:987–993, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Full‐field Peak Pressure Prediction of Shock Waves from Underwater Explosion of Cylindrical Charges
Authors: Liu Lei , Guo Rui , Gao Ke , Zeng Ming‐chao 
Published: May 2017

AbstractCylindrical charge is a main form in most application of explosives. By employing numerical calculation and an indirect mapping method, the relation between peak pressures from underwater explosion of cylindrical and spherical charges is investigated, and further a model to predict full‐field peak pressures by the former one is developed and then verified by experiments. Besides, a method to intuitively sketch the corresponding orientational performance is proposed and discussed. The results indicate the following: when R/R0 ranges from 12 to 100, the mapping relation is nearly dominated by the amplitude similarity constant Kp, and an approximate shifted sine relation between Kp/K0 and action angle exists; in cases that L/d is over 1.5, the prediction model shows a good agreement with experimental data, with most errors below 10% and it is also universally applicable for different explosives; the directivity of peak pressure distribution in underwater explosion is continuously improved along the increasing L/d but no significant influence appears after L/d becomes over 5.
What drives ‘soft deportation’? Understanding the rise in Assisted Voluntary Return among rejected asylum seekers in the Netherlands
Authors: Leerkes Arjen , van Os Rianne , Boersema Eline 
Published: May 2017

AbstractStates experience difficulties in realizing the return of rejected asylum seekers, but migration control policies are becoming increasingly sophisticated. Against this background, we consider explanations for the increase in Assisted Voluntary Return from the Netherlands in the 2005–2011 period. Both macro‐level factors (source country societal conditions and characteristics of the Dutch “deportation regime”) and individual‐level factors (applicants' demographic characteristics and variation in status determination time) are examined. The study, which is based on a unique multilevel dataset (N = 15,682) with data from governmental and other sources (including International Organisation for Migration), is the first to quantitatively test assumed Assisted Voluntary Return determinants and contributes to the study of policy effects in migration studies. We find that states are capable of increasing return rates by expanding the use of “hard” and “soft” power. We propose the term “soft deportation” as a way to go beyond the dichotomy of “voluntary” and “forced” return.
Classification of natural flow regimes in Poland
Authors: Piniewski M. 
Published: May 2017

AbstractHydrological classifications are aimed at simplifying spatiotemporal variability of flow regimes and, secondly, at supporting environmental flow management. The objective of this study was to perform classification of natural flow regimes in Poland using an inductive approach based on a set of hydrological metrics (HMs) and to develop a model for prediction of class membership based on a set of environmental variables (EVs). A set of 147 gauges with unmodified flow regimes was identified, and for each gauge, values of 73 HMs and 28 EVs were computed. Classification was performed using k‐means and k‐medoids techniques, based on 4 principal components explaining 73.4% of variability in HMs. Out of 7 distinguished classes, 4 (P1–P4) were spread across the Polish Plain, 1 (U5) was restricted to uplands, and 2 (M6 and M7) to mountains. The between‐class differences in HMs and EVs were generally high, although classes P1 and P3 were not easily distinguishable. Mean predictive accuracy of the developed random forest model was 79%, which is high compared to other studies of this type. The lowest accuracies (0 and 50%) were achieved by 2 classes with the lowest counts. Variables representing diverse aspects: hydrography, climate, topography, and geology had the highest importance in the random forest model. Future research can benefit from the database of selected gauges with computed HMs, EVs, and assigned classes, freely available through a long‐lasting data repository. With this study, the first step towards application of the ELOHA framework for environmental flow management at regional scale has been achieved.
CD36 Is a Marker of Human Adipocyte Progenitors with Pronounced Adipogenic and Triglyceride Accumulation Potential
Authors: Gao Hui , Volat Fanny , Sandhow Lakshmi , Galitzky Jean , Nguyen Thuy , Esteve David , Åström Gaby , Mejhert Niklas , Ledoux Severine , Thalamas Claire , Arner Peter , Guillemot Jean-Claude , Qian Hong , Rydén Mikael , Bouloumié Anne 
Published: May 2017

Abstract
White adipose tissue (WAT) expands in part through adipogenesis, a process involving fat cell generation and fatty acid (FA) storage into triglycerides (TGs). Several findings suggest that inter-individual and regional variations in adipogenesis are linked to metabolic complications. We aimed to identify cellular markers that define human adipocyte progenitors (APs) with pronounced adipogenic/TG storage ability. Using an unbiased single cell screen of passaged human adipose-derived stromal cells (hADSCs), we identified cell clones with similar proliferation rates but discordant capabilities to undergo adipogenic differentiation. Transcriptomic analyses prior to induction of differentiation showed that adipogenic clones displayed a significantly higher expression of CD36, encoding the scavenger receptor CD36. CD36+ hADSCs, in comparison with CD36-cells, displayed almost complete adipogenic differentiation while CD36 RNAi attenuated lipid accumulation. Similar findings were observed in primary CD45-/CD34+/CD31-APs isolated from human WAT where the subpopulation of MSCA1+/CD36+ cells displayed a significantly higher differentiation degree/TG storage capacity than MSCA1+/CD36-cells. Functional analyses in vitro and ex vivo confirmed that CD36 conferred APs an increased capacity to take up FAs thereby facilitating terminal differentiation. Among primary APs from subcutaneous femoral, abdominal and visceral human WAT, the fraction of CD36+ cells was significantly higher in depots associated with higher adipogenesis and reduced metabolic risk (i.e., femoral WAT). We conclude that CD36 marks APs with pronounced adipogenic potential, most probably by facilitating lipid uptake. This may be of value in developing human adipocyte cell clones and possibly in linking regional variations in adipogenesis to metabolic phenotype.
Thiolate‐protected gold nanoclusters: structural prediction and the understandings of electronic stability from first principles simulations
Authors: Ma Zhongyun , Wang Pu , Xiong Lin , Pei Yong 
Published: May 2017

Thiolate‐protected gold nanoclusters (RS‐AuNCs) have aroused intensive research interests in field of nanoscience since the breakthroughs in structural determination of Au102(SR)44, Au25(SR)18
−, and Au38(SR)24 achieved by both theory and experiment. To date, single crystal structures of about 20 thiolate‐protected gold nanoclusters had been successfully resolved. The analysis on the structural patterns of the high symmetric cores and the types and numbers of the protecting ligand motifs in these nanoclusters provides deep insight into the inherent structural rule. On this basis, the developed conceptual models not only rationalize the known structures, but also help to predict new ones. Given that the synthesis and crystallization of RS‐AuNCs in experiment still remain challenging, theoretical calculations based on density functional theory play a crucial role in structural prediction. Herein, three developed conceptual models for explaining electronic stability and the recent progress of structural prediction through first principles simulations are highlighted. As more atomically precise structures of RS‐AuNCs being determined, further understanding of the structure–property relationships is expected to achieve and boost practical applications of metal nanoclusters. WIREs Comput Mol Sci 2017, 7:e1315. doi: 10.1002/wcms.1315This article is categorized under:

Structure and Mechanism > Molecular Structures