bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolated left ventricular failure is a predictor of poor outcome in patients receiving veno‐arterial extracorporeal membrane oxygenation
Authors: den Uil Corstiaan A. , Jewbali Lucia S. , Heeren Martijn J. , Constantinescu Alina A. , Van Mieghem Nicolas M. , Reis Miranda Dinis dos
Published: May 2017

Aims

We investigated survival according to the nature of heart failure (isolated left, vs isolated right, vs biventricular heart failure) in patients undergoing extracorporeal membrane oxygenation (ECMO) for refractory cardiogenic shock of different causes.

Methods and results

This single‐center study included 132 patients with acute myocardial infarction (20%), acute on chronic heart failure (14%), post cardiotomy (17%), cardiac allograft failure (8%), pulmonary embolism (16%), and acute nonischemic heart failure (25%). Ventricular function was a priori assessed by transthoracic echocardiography (isolated left (26%), isolated right (22%), or biventricular heart failure (52%)). The primary endpoint was all‐cause mortality at 90 days and long‐term. Predictors for adverse outcome were identified by univariate and multivariate Cox regression analysis.

Median duration of ECMO support was 6 [3–9] days. Ninety‐day survival was 51% (isolated LV failure 32% vs. isolated RV failure 62% vs. biventricular failure 55%, p = 0.04). The presence of isolated left ventricular failure was a predictor for 90‐day mortality, irrespective of diagnosis and SAVE score. In patients who survived 90 days following ECMO implantation, long‐term (4‐year) survival was excellent (95%, no difference between subgroups).

Conclusion

Isolated left ventricular failure was an independent predictor for 90‐day outcome.
MicroRNA‐142 controls thymocyte proliferation
Authors: Mildner Alexander , Chapnik Elik , Varol Diana , Aychek Tegest , Lampl Nardi , Rivkin Natalia , Bringmann Anita , Paul Franziska , Boura‐Halfon Sigalit , Hayoun Yifat Segal , Barnett‐Itzhaki Zohar , Amit Ido , Hornstein Eran , Jung Steffen
Published: May 2017

T‐cell development is a spatially and temporally regulated process, orchestrated by well‐defined contributions of transcription factors and cytokines. Here, we identify the noncoding RNA miR‐142 as an additional regulatory layer within murine thymocyte development and proliferation. MiR‐142 deficiency impairs the expression of cell cycle‐promoting genes in mature mouse thymocytes and early progenitors, accompanied with increased levels of cyclin‐dependent kinase inhibitor 1B (Cdkn1b, also known as p27Kip1). By using CRISPR/Cas9 technology to delete the miR‐142‐3p recognition element in the 3’UTR of cdkn1b, we confirm that this gene is a novel target of miR‐142‐3p in vivo. Increased Cdkn1b protein expression alone however was insufficient to cause proliferation defects in thymocytes, indicating the existence of additional critical miR‐142 targets. Collectively, we establish a key role for miR‐142 in the control of early and mature thymocyte proliferation, demonstrating the multifaceted role of a single miRNA on several target genes.
Boundary frame contribution in coupled and uncoupled steel plate shear walls
Authors: Wang Meng , Borello Daniel J. , Fahnestock Larry A.
Published: May 2017

The steel plate shear wall (SPSW) system is a robust option for earthquake resistance due to the strength, stiffness, ductility and energy dissipation that it provides. Although thin infill plates are efficient for resisting lateral loads, boundary frames that are proportioned based on capacity design requirements add significant structural weight that appears to be one of the factors limiting the use of the system in practice. An alternate configuration, the SPSW with coupling (SPSW‐WC), was explored recently as an option for increasing architectural flexibility while also improving overall system economy and seismic performance. The SPSW‐WC, which extensively employs flexural boundary frame contribution, has shown promise in analytical, numerical and experimental studies, but recent research on uncoupled SPSWs suggests that boundary frame contribution should not be considered for carrying seismic design shear. As a result, in the present study, boundary frame contribution in SPSWs was explored with detailed three‐dimensional finite element models, which were validated against large‐scale SPSW‐WC tests. Six‐story systems were considered, and the study matrix included single and double uncoupled SPSWs along with coupled SPSWs that had various degrees of coupling. Variations in design methodology were also explored. The modeling framework was employed to conduct static monotonic and cyclic pushover analyses and dynamic response history analysis. These analyses demonstrate the beneficial effect of coupling in SPSWs and illustrate the need to consider boundary frame contribution in design of coupled SPSWs. In addition, sharing design shear between the infill plate and the boundary frame is more generally shown to not be detrimental if this sharing is done in the design stage based on elastic analysis and the resulting boundary frame provides adequate secondary strength and stiffness following infill plate yielding. Copyright © 2017 John Wiley & Sons, Ltd.
The rapid mass calorimeter: A route to high throughput fire testing
Authors: Rabe Sebastian , Schartel Bernhard
Published: May 2017

The rapid mass calorimeter based on reduced‐size specimens is proposed for accelerated fire testing and put up for discussion, particularly for flame retarded polymeric materials. A mass loss calorimeter is combined with a semiautomatic sample changer. Experiments on specimens of reduced size were conducted on poly(methyl methacrylate), poly(propylene), polyamide 66, poly(ether ether ketone), and pine sapwood square samples with edge lengths of 100, 75, 50, 25, 20, and 10 mm. Specimens of 20 × 20 mm2 were selected to achieve a crucial reduction in specimen size and a measuring protocol developed. A total of 71 different polymeric materials were investigated in the rapid mass calorimeter and cone calorimeter for comparison and several materials with different heat release rate characteristics in the pyrolysis combustion flow calorimeter to test this additional screening method as well. The important fire properties obtained in the rapid mass calorimeter show reasonable correlation with the cone calorimeter results but also with the oxygen index. All in all, the rapid mass calorimeter produces reliable and meaningful results and, despite acceleration and size reduction, still allows for a certain degree of burning behavior interpretation. Material savings of 96% and time savings of around 60%‐70% are achieved compared to measure cone calorimeter.
A presumed antagonistic LPS identifies distinct functional organization of TLR4 in mouse microglia
Authors: Döring Christin , Regen Tommy , Gertig Ulla , van Rossum Denise , Winkler Anne , Saiepour Nasrin , Brück Wolfgang , Hanisch Uwe‐Karsten , Janova Hana
Published: May 2017

Microglia as principle innate immune cells of the central nervous system (CNS) are the first line of defense against invading pathogens. They are capable of sensing infections through diverse receptors, such as Toll‐like receptor 4 (TLR4). This receptor is best known for its ability to recognize bacterial lipopolysaccharide (LPS), a causative agent of gram‐negative sepsis and septic shock. A putative, naturally occurring antagonist of TLR4 derives from the photosynthetic bacterium Rhodobacter sphaeroides. However, the antagonistic potential of R. sphaeroides LPS (Rs‐LPS) is no universal feature, since several studies suggested agonistic rather than antagonistic actions of this molecule depending on the investigated mammalian species. Here we show the agonistic versus antagonistic potential of Rs‐LPS in primary mouse microglia. We demonstrate that Rs‐LPS efficiently induces the release of cytokines and chemokines, which depends on TLR4, MyD88, and TRIF, but not CD14. Furthermore, Rs‐LPS is able to regulate the phagocytic capacity of microglia as agonist, while it antagonizes Re‐LPS‐induced MHC I expression. Finally, to our knowledge, we are the first to provide in vivo evidence for an agonistic potential of Rs‐LPS, as it efficiently triggers the recruitment of peripheral immune cells to the endotoxin‐challenged CNS. Together, our results argue for a versatile and complex organization of the microglial TLR4 system, which specifically translates exogenous signals into cellular functions. Importantly, as demonstrated here for microglia, the antagonistic potential of Rs‐LPS needs to be considered with caution, as reactions to Rs‐LPS not only differ by cell type, but even by function within one cell type.
Supercritical CO2 assisted process for the production of high‐purity and sterile nano‐hydroxyapatite/chitosan hybrid scaffolds
Authors: Ruphuy G. , Souto‐Lopes M. , Paiva D. , Costa P. , Rodrigues A. E. , Monteiro F. J. , Salgado C. L. , Fernandes M. H. , Lopes J. C. , Dias M. M. , Barreiro M. F.
Published: May 2017

Hybrid scaffolds composed of hydroxyapatite (HAp), in particular in its nanometric form (n‐HAp), and chitosan (CS) are promising materials for non‐load‐bearing bone graft applications. The main constraints of their production concern the successful implementation of the final purification/neutralization and sterilization steps. Often, the used purification strategies can compromise scaffold structural features, and conventional sterilization techniques can result in material's thermal degradation and/or contamination with toxic residues. In this context, this work presents a process to produce n‐HAp/CS scaffolds mimicking bone composition and structure, where an innovative single step based on supercritical CO2 extraction was used for both purification and sterilization. A removal of 80% of the residual acetic acid was obtained (T = 75°C, p = 8.0 MPa, 2 extraction cycles of 2 h) giving rise to scaffolds exhibiting adequate interconnected porous structure, fast swelling and storage modulus compatible with non‐load‐bearing applications. Moreover, the obtained scaffolds showed cytocompatibility and osteoconductivity without further need of disinfection/sterilization procedures. Among the main advantages, the proposed process comprises only three steps (n‐HAp/CS dispersion preparation; freeze‐drying; and supercritical CO2 extraction), and the supercritical CO2 extraction show clear advantages over currently used procedures based on neutralization steps. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 965–975, 2018.
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

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.
Jumping between protein conformers using normal modes
Authors: Mahajan Swapnil , Sanejouand Yves‐Henri
Published: May 2017

The relationship between the normal modes of a protein and its functional conformational change has been studied for decades. However, using this relationship in a predictive context remains a challenge. In this work, we demonstrate that, starting from a given protein conformer, it is possible to generate in a single step model conformers that are less than 1 Å (Cα‐RMSD) from the conformer which is the known endpoint of the conformational change, particularly when the conformational change is collective in nature. Such accurate model conformers can be generated by following either the so‐called robust or the 50 lowest‐frequency modes obtained with various Elastic Network Models (ENMs). Interestingly, the quality of many of these models compares well with actual crystal structures, as assessed by the ROSETTA scoring function and PROCHECK. The most accurate and best quality conformers obtained in the present study were generated by using the 50 lowest‐frequency modes of an all‐atom ENM. However, with less than ten robust modes, which are identified without any prior knowledge of the nature of the conformational change, nearly 90% of the motion described by the 50 lowest‐frequency modes of a protein can be captured. Such results strongly suggest that exploring the robust modes of ENMs may prove efficient for sampling the functionally relevant conformational repertoire of many proteins. © 2017 Wiley Periodicals, Inc.
Fasting inhibits hepatic stellate cells activation and potentiates anti‐cancer activity of Sorafenib in hepatocellular cancer cells
Authors: Lo Re Oriana , Panebianco Concetta , Porto Stefania , Cervi Carlo , Rappa Francesca , Di Biase Stefano , Caraglia Michele , Pazienza Valerio , Vinciguerra Manlio
Published: May 2017

Hepatocellular carcinoma (HCC) has a poor outcome. Most HCCs develop in the context of liver fibrosis and cirrhosis caused by chronic inflammation. Short‐term fasting approaches enhance the activity of chemotherapy in preclinical cancer models, other than HCC. Multi‐tyrosine kinase inhibitor Sorafenib is the mainstay of treatment in HCC. However, its benefit is frequently short‐lived. Whether fasting can alleviate liver fibrosis and whether combining fasting with Sorafenib is beneficial remains unknown. A 24 hr fasting (2% serum, 0.1% glucose)‐induced changes on human hepatic stellate cells (HSC) LX‐2 proliferation/viability/cell cycle were assessed by MTT and flow cytometry. Expression of lypolysaccharide (LPS)‐induced activation markers (vimentin, αSMA) was evaluated by qPCR and immunoblotting. Liver fibrosis and inflammation were evaluated in a mouse model of steatohepatitis exposed to cycles of fasting, by histological and biochemical analyses. A 24 hr fasting‐induced changes were also analyzed on the proliferation/viability/glucose uptake of human HCC cells exposed to Sorafenib. An expression panel of genes involved in survival, inflammation, and metabolism was examined by qPCR in HCC cells exposed to fasting and/or Sorafenib. Fasting decreased the proliferation and the activation of HSC. Repeated cycles of short term starvation were safe in mice but did not improve fibrosis. Fasting synergized with Sorafenib in hampering HCC cell growth and glucose uptake. Finally, fasting normalized the expression levels of genes which are commonly altered by Sorafenib in HCC cells. Fasting or fasting‐mimicking diet diets should be evaluated in preclinical studies as a mean to potentiate the activity of Sorafenib in clinical use.
Folic acid is necessary for proliferation and differentiation of C2C12 myoblasts
Authors: Hwang Seong Y. , Kang Yong J. , Sung Bokyung , Jang Jung Y. , Hwang Na L. , Oh Hye J. , Ahn Yu R. , Kim Hong J. , Shin Jin H. , Yoo Mi‐ae , Kim Cheol M. , Chung Hae Y. , Kim Nam D.
Published: May 2017

Folic acid, a water soluble B vitamin, plays an important role in cellular metabolic activities, such as functioning as a cofactor in one‐carbon metabolism for DNA and RNA synthesis as well as nucleotide and amino acid biosynthesis in the body. A lack of dietary folic acid can lead to folic acid deficiency and result in several health problems, including macrocytic anemia, elevated plasma homocysteine, cardiovascular disease, birth defects, carcinogenesis, muscle weakness, and walking difficulty. However, the effect of folic acid deficiency on skeletal muscle development and its molecular mechanisms are unknown. We, therefore, investigated the effect of folic acid deficiency on myogenesis in skeletal muscle cells and found that folic acid deficiency induced proliferation inhibition and cell cycle breaking as well as cellular senescence in C2C12 myoblasts, implying that folic acid deficiency influences skeletal muscle development. Folic acid deficiency also inhibited differentiation of C2C12 myoblasts and induced deregulation of the cell cycle exit and many cell cycle regulatory genes. It inhibited expression of muscle‐specific marker MyHC as well as myogenic regulatory factor (myogenin). Moreover, immunocytochemistry and Western blot analyses revealed that DNA damage was more increased in folic acid‐deficient medium‐treated differentiating C2C12 cells. Furthermore, we found that folic acid resupplementation reverses the effect on the cell cycle and senescence in folic acid‐deficient C2C12 myoblasts but does not reverse the differentiation of C2C12 cells. Altogether, the study results suggest that folic acid is necessary for normal development of skeletal muscle cells.
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

Purpose

To 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 Methods

Acceleration 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).

Results

For 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).

Conclusion

In 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: 1

Technical Efficacy: Stage 2

J. 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

This 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

Objectives

The 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).

Methods

A 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.

Results

The 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).

Conclusions

Inhalable 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

Objectives

To 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.

Methods

In 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.

Results

Deep 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.

Conclusions

Qualitative 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

While 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

Purpose

To evaluate the combination of nonenhanced quiescent‐interval slice‐selective (QISS) magnetic resonance angiography (MRA) with super‐resolution reconstruction for portraying the intracranial arteries.

Methods

The 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.

Results

For 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.

Conclusion

Thin, 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

Purpose

The 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.

Methods

DWI 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.

Results

Using 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.

Conclusions

An 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.
Preparation and characterization of PbO/carboxymethyl cellulose/polyvinylpyrrolidone nanocomposite films
Authors: El‐Bana M.S. , Mohammed Gh. , El Sayed Adel M. , El‐Gamal S.
Published: May 2017

Lead oxide nanoparticles (PbO NPs) and carboxymethyl cellulose (CMC)/polyvinylpyrrolidone (PVP) nanocomposite films were prepared by sol‐gel and solution casting methods respectively. The structural properties of the samples were investigated by X‐ray diffraction (XRD), high‐resolution transmission electron microscopy (HR‐TEM) and Fourier transformation infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) revealed the good dispersion of PbO NPs on the surface of the blend films. CMC film exhibits a transmittance (T) of 72%, increased after mixing with PVP and then decreased to <38% after adding 4.0 wt% PbO NPs. Both the direct and indirect optical band gaps (Eg) of CMC equal to 3.97 and 3.7 eV, respectively. These values were increased after PVP addition and then decreased after loading PbO NPs. The conduction mechanism in CMC/PVP blend has changed from Schottky emission to Poole–Frenkel due to the effects of temperature and PbO NPs content. The effect of adding PVP & PbO NPs on the DC conductivity and the activation energy Ea values of the CMC are discussed. The dielectric constant (ε′) was investigated in the frequency and temperature ranges of 1 kHz–1.0 MHz and 293–393 K respectively. Its values depend on both the PbO content and temperature. The AC conductivity σac was increased with increasing PbO content. The correlated barrier hopping (CBH) was found to be the most appropriate mechanism for explaining the AC conduction behavior. POLYM. COMPOS., 39:3712–3725, 2018. © 2017 Society of Plastics Engineers
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

Cylindrical 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

States 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

Hydrological 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.
Autoregressive and cross‐lagged model for bivariate non‐commensurate outcomes
Authors: He Fei , Teixeira‐Pinto Armando , Harezlak Jaroslaw
Published: May 2017

Autoregressive and cross‐lagged models have been widely used to understand the relationship between bivariate commensurate outcomes in social and behavioral sciences, but not much work has been carried out in modeling bivariate non‐commensurate (e.g., mixed binary and continuous) outcomes simultaneously. We develop a likelihood‐based methodology combining ordinary autoregressive and cross‐lagged models with a shared subject‐specific random effect in the mixed‐model framework to model two correlated longitudinal non‐commensurate outcomes. The estimates of the cross‐lagged and the autoregressive effects from our model are shown to be consistent with smaller mean‐squared error than the estimates from the univariate generalized linear models. Inclusion of the subject‐specific random effects in the proposed model accounts for between‐subject variability arising from the omitted and/or unobservable, but possibly explanatory, subject‐level predictors. Our model is not restricted to the case with equal number of events per subject, and it can be extended to different types of bivariate outcomes. We apply our model to an ecological momentary assessment study with complex dependence and sampling data structures. Specifically, we study the dependence between the condom use and sexual satisfaction based on the data reported in a longitudinal study of sexually transmitted infections. We find negative cross‐lagged effect between these two outcomes and positive autoregressive effect within each outcome. Copyright © 2017 John Wiley & Sons, Ltd.
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

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.
Experimental evaluation of lightweight aggregate concrete beam–column joints with different strengths and reinforcement ratios
Authors: Carmo Ricardo N. F. do , Costa Hugo , Gomes Gonçalo , Valença Jonatas
Published: May 2017

The performance of beam–column joints significantly affects the overall behavior of reinforced concrete (RC) frames and, in some cases, can reduce the load carrying capacity and increase the lateral displacements of the frames. Also, when simultaneously small cross sections and a high number of rebar are used, the reinforcement detailing and the casting of concrete can be a difficult task. Despite this, there is a lack of attention for design and detailing the RC joints. The experimental study herein presented is focused on the behavior of exterior beam–column joints of lightweight aggregate concrete (LWAC) under monotonic loads. The study aims to evaluate the influence of rebar detailing of LWAC strength and of reinforcement ratio on the joints’ behavior. Five specimens, combining different reinforcement ratios and concrete strengths, were properly monitored and tested. The strength capacity, deformability, and stiffness of the LWAC joints were analyzed. The experimental results enhance the importance of an adequate reinforcement detailing of the beam–column joint, because incorrect detailing decreases considerably the load capacity. Based on the results, it is highly recommended to use larger columns than beams, to reduce the cracking and increase the joint's stiffness.
A new under‐voltage load shedding scheme for islanded distribution system based on voltage stability indices
Authors: Yusof Nurul Aisyah , Mohd Rosli Hazwani , Mokhlis Hazlie , Karimi Mazaher , Selvaraj Jeyraj , Sapari Norazliani Md
Published: May 2017

Under‐voltage load shedding (UVLS) is an important technique to maintain the voltage stability and frequency of a power system network. UVLS has been applied widely in transmission systems to avoid system blackouts. However, with increasing penetration of distributed generation such as photovoltaic (PV) systems, the application of UVLS becomes important for islanded distribution systems. Under this condition, the network does not have a frequency reference as when it is connected to the grid. In this condition, when the load demand exceeds the PV capacity, UVLS is the only option to stabilize the system by shedding the load based on the changes of the voltage magnitude. In this work, a new UVLS scheme based on voltage stability indices is proposed. Four voltage stability indices are used as indicators for load shedding. Based on the stability indices, the loads that have the highest tendency of voltage collapse shall be the first ones to be shed. The proposed scheme is tested on a practical distribution network energized by a grid, a mini hydro generator, and a PV system. The test results on various scenarios prove that the proposed method is able to restore the system stability. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Re: Prospective temporal validation of mathematical models to calculate risk of endometrial malignancy in patients with postmenopausal bleeding. P. Sladkevicius, G. Opolskiene and L. Valentin. Ultrasound Obstet Gynecol 2017;49: 649–656.
Authors: Jurkovic D.
Published: May 2017

Linked Comment: Ultrasound Obstet Gynecol 2017;49: 649–656
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.1315

This article is categorized under:

Structure and Mechanism > Molecular Structures
Moment‐matching based model reduction for Navier–Stokes type quadratic‐bilinear descriptor systems
Authors: Ahmad Mian Ilyas , Benner Peter , Goyal Pawan , Heiland Jan
Published: May 2017

We discuss a Krylov subspace projection method for model reduction of a special class of quadratic‐bilinear descriptor systems. The goal is to extend the two‐sided moment‐matching method for quadratic‐bilinear ODEs to descriptor systems in an efficient and reliable way. Recent results have shown that the direct application of interpolation based model reduction techniques to linear descriptor systems, without any modifications, may lead to poor reduced‐order systems. Therefore, for the analysis, we transform the quadratic‐bilinear descriptor system into an equivalent quadratic‐bilinear ODE system for which the moment‐matching is performed. In view of implementation, we provide algorithms that identify the required Krylov subspaces without explicitly computing the projectors used in the analysis. The benefits of our approach are illustrated for the quadratic‐bilinear descriptor systems corresponding to semi‐discretized Navier–Stokes equations.