bluuebunny/crossref_metadata_2025 huggingface dataset:
Space–time pressure–velocity correlations in a turbulent boundary layer
Authors: Naka Yoshitsugu , Stanislas Michel , Foucaut Jean-Marc , Coudert Sebastien , Laval Jean-Philippe , Obi Shinnosuke
Published: April 2015

The spatio-temporal pressure–velocity correlation in a turbulent boundary layer is investigated so as to understand the link between pressure fluctuations and turbulent coherent structures. A new experimental set-up is developed to measure the pressure fluctuations at the wall and in the field and, simultaneously, the velocity field by stereoscopic particle image velocimetry. The present measurement area covers the whole boundary layer thickness, and the spatial resolution of the measurement is good enough to assess the representative length scales of the flow. The Reynolds number effect is quantified from the data at $\mathit{Re}_{{\it\theta}}=7300$, 10 000, 18 000. The spatio-temporal three-dimensional structures of the pressure–velocity correlations, $\boldsymbol{R}_{pu}$, $\boldsymbol{R}_{pv}$ and $\boldsymbol{R}_{pw}$, are evaluated. The wall pressure fluctuations are closely coupled with coherent structures which occupy a large region of the boundary layer in the wall-normal and spanwise directions and up to $10{\it\delta}/U_{e}$ in time, where ${\it\delta}$ and $U_{e}$ denote the boundary layer thickness and the free stream velocity. Reynolds number effects are mainly observed on the size and intensity of the pressure–velocity correlations. Conditioning the correlations on the pressure signal sign shows different types of flow phenomena linked to the positive and negative pressure events. For the wall pressure, positive pressure fluctuations appear to be correlated with the leading edge of a large sweeping motion of splatting type followed by a large ejection. The negative pressure fluctuations are linked to a localized ejection upstream, followed by a large sweeping motion downstream. For the pressure fluctuations in the field, in addition to the structures observed with the wall pressure, the pressure–velocity correlations exhibit a significant correlation in a region very extended in time. Such long structures appear to be independent of the one observed at the wall and to grow significantly in time with the Reynolds number when scaling with external variables. When conditioned by the pressure sign, clear ejection and sweeping motions are observed with associated streamwise vortical structures at a scale of the order of $0.2{\it\delta}$. These structures can be linked to the large-scale motion and very-large-scale motion previously observed by different authors and seem to organize in a scheme analogous to the near-wall cycle, but at a much larger scale.
‘If I Wanted to Have More Opportunities and Go to a Better School, I Just Had to Get Used to It’: Aboriginal Students’ Perceptions of Going to Boarding School in Western Australia
Authors: Mander David J. , Cohen Lynne , Pooley Julie Ann
Published: April 2015

This study explored the experiences of 32 male Aboriginal students from regional and remote towns and communities while they attended a metropolitan boarding school away from home and family in Perth, Western Australia. Using narrative interviews it specifically investigated how these Aboriginal students construct meaning around the transition experience to boarding school. Three major themes emerged from the data: (1) Decision Making and the subthemes of Choice-less Choice and Opportunity; (2) Organisational Climate and the subthemes of School Environment and Belonging, Culture Shock, Homesickness, Identity, Code Switching, Teachers, Academic Expectations, Residential Life, and Friendships and Peer Relations; and (3) Relational Change and the subthemes of Family Dynamics, Friendships at Home, and Cultural Connectedness. This study emphasises the importance of conceptualising and understanding social phenomena from the perspective of those who actually undertake the experience, and the findings are discussed in terms of policy and practice relevant to Australian boarding schools.
Genomic composition and yield heterosis of the partial inter-specific hybrid rice between Oryza sativa L. and Oryza glaberrima Steud.
Authors: ADEDZE Y. M. N. , HE W. C. , SAMOURA A. D. , HUANG F. , TONDI Y. N. , EFISUE A. , ZHANG S. S. , XIE G. S. , JIN D. M.
Published: April 2015

Development of partial inter-specific hybrid (PIH) rice is a promising approach for exploiting inter-specific heterosis between Oryza glaberrima and Oryza sativa. In the present study, the relationship between genetic distance (GD) of parental lines and yield performance of the PIHs was assessed using partial diallel crosses between three indica male sterile lines and 14 introgression lines (ILs) with different fragments of O. glaberrima genes. Twenty two out of the 42 PIHs expressed positive heterobeltiosis (i.e., the Fl hybrid showed superiority over the better parent in the target trait) for panicle number, spikelet number, thousand grain weight and grain yield/plant. The proportion of O. glaberrima genome in the ILs ranged from 0·03 to 0·41, as revealed by 16 informative simple sequence repeat markers. Significant positive correlations were found between the proportion of O. glaberrima genome of the ILs and the GD between the ILs and the three different female parents. Heterosis of spikelet number per panicle in the hybrids was positively proportional with the O. glaberrima genome content of the parental ILs, while that of fertile grain percentage was negatively proportional to the O. glaberrima genome proportion. On average, the PIHs with higher grain yield and highest heterobeltiosis were obtained from the ILs carrying between 0·15 and 0·30 of O. glaberrima genome. The results indicated that a small proportion (<0·15) of the O. glaberrima genome in the ILs might limit heterosis expression of spikelet number per panicle, while a very large proportion (>0·30) of the O. glaberrima genome decreased the grain filling percentage in the PIHs, thus an intermediate range of O. glaberrima genome proportion should be more suitable for breeding heterotic PIHs. The exploitation of inter-specific heterosis between O. glaberrima and O. sativa has potential value for heterotic breeding in rice.
Mechanism and kinetics of early transition metal hydrides, oxides, and chlorides to enhance hydrogen release and uptake properties of MgH2
Authors: Korablov Dmytro , Nielsen Thomas K. , Besenbacher Flemming , Jensen Torben R.
Published: April 2015

Selected hydrides (TiH2, ZrH2), chlorides (VCl3, ScCl3) or oxides (V2O5) utilized as additives facilitating hydrogen release and uptake for magnesium hydride were investigated using mechano-chemical treatment and in-situ synchrotron radiation powder X-ray diffraction studies. The fastest hydrogen desorption and absorption kinetics for MgH2 was observed for a sample with 5 mol% V2O5 at 320 °C. Additional activation of the system (2 cycles, vacuum/p(H2) ~150 bar, 450 °C) leads to significant improvement of the kinetics even at lower temperatures, 270 °C. The observed prolific effect is achieved through the full reduction of vanadium oxides and formation of an efficient vanadium catalyst as nanoparticles and possibly interfacial effects in the MgO/Mg/MgH2/V system introduced during cycling hydrogen release and uptake in hydrogen/dynamic vacuum at 450 °C. Nanostructuring as well as hydrogen permeability via vanadium nanoparticles may improve kinetics and reduce the apparent activation energy for hydrogen release. Thus, the enhancement of hydrogen release/uptake in the MgH2 owe to “in situ” formation of vanadium nanoparticles by reduction of V2O5.
Geochemistry of recent lacustrine sediments from Fildes Peninsula, King George Island, maritime Antarctica
Authors: Alfonso Juan A. , Vasquez Yaneth , Hernandez Ana C. , Mora Abrahan , Handt Helga , Sira Eloy
Published: April 2015

Comprehensive geochemical analyses (bulk parameters, major and trace elements, organic matter, mineralogy and particle analysis) were carried out on sediments from seven lakes on Fildes Peninsula, King George Island. The resulting compositional dataset was subjected to principal component analysis and cluster analysis. The results showed that four different lacustrine sedimentary environments can be distinguished: i) lakes 1 and 2 with relatively high values of secondary aluminous clay minerals, ii) lake 4 with anthropogenic enrichment of Co, Cu and Zn, iii) lake 7 with relatively high values of Ba and P and a high zeolite content, and iv) all the other studied lakes. Our results indicate moderate chemical weathering in all lacustrine sediments and that the distance to the glacial ice margin is one of the most important factors influencing the chemical weathering in the area. Furthermore, depositional processes have little influence on the geochemistry of the investigated elements and that local bedrock is the main source of sediments in the lakes on Fildes Peninsula.
Chlorophyta, Xanthophyceae and Cyanobacteria in Wright Valley, Antarctica
Authors: Novis Phil M. , Aislabie Jackie , Turner Susan , McLeod Malcolm
Published: April 2015

Wright Valley, Victoria Land contains numerous aquatic habitats suitable for the growth of algae in summer. Excepting diatoms and lichen phycobionts, algal diversity and distribution in the valley was documented. Using cultures and environmental cloning eight cyanobacterial and 14 eukaryotic species were revealed. The cyanobacterium Microcoleus vaginatus and the chlorophycean Chlorococcum sp. 1 were the most common, both occurring in more than one habitat (ponds, soils or streams). Ponds harboured the most diverse communities. Habitat specialization was rare. Chlamydomonads were not found outside ponds, but species capable of zoospore production were able to colonize ponds and soils. Nostocalean cyanobacteria were not detected. Results suggest dispersal within and between valleys, with little evidence of Antarctic endemism. All but one cyanobacterium with similar internally transcribed spacer (ITS) length to clones from Miers Valley proved to be different species when 16S rRNA gene sequences were also considered; thus, ITS length is unreliable for assessing identity and biogeography of these cyanobacteria. Comparison with a 454 16S rRNA gene soil dataset from Wright Valley indicated the occurrence of only one of the cyanobacterial species, the distribution of which may be limited by salinity.
Impulsivity and aggression in schizophrenia: a neural circuitry perspective with implications for treatment
Authors: Hoptman Matthew J.
Published: April 2015

Elevations of impulsive behavior have been observed in a number of serious mental illnesses. These phenomena can lead to harmful behaviors, including violence, and thus represent a serious public health concern. Such violence is often a reason for psychiatric hospitalization, and it often leads to prolonged hospital stays, suffering by patients and their victims, and increased stigmatization. Despite the attention paid to violence, little is understood about its neural basis in schizophrenia. On a psychological level, aggression in schizophrenia has been primarily attributed to psychotic symptoms, desires for instrumental gain, or impulsive responses to perceived personal slights. Often, multiple attributions can coexist during a single aggressive incident. In this review, I discuss the neural circuitry associated with impulsivity and aggression in schizophrenia, with an emphasis on implications for treatment. Impulsivity appears to account for a great deal of aggression in schizophrenia, especially in inpatient settings. Urgency, defined as impulsivity in the context of strong emotion, is the primary focus of this article. It is elevated in several psychiatric disorders, and in schizophrenia, it has been related to aggression. Many studies have implicated dysfunctional frontotemporal circuitry in impulsivity and aggression in schizophrenia, and pharmacological treatments may act via that circuitry to reduce urgency and aggressive behaviors; however, more mechanistic studies are critically needed. Recent studies point toward manipulable neurobehavioral targets and suggest that cognitive, pharmacological, neuromodulatory, and neurofeedback treatment approaches can be developed to ameliorate urgency and aggression in schizophrenia. It is hoped that these approaches will improve treatment efficacy.
Clustering-Initiated Factor Analysis Application for Tissue Classification in Dynamic Brain Positron Emission Tomography
Authors: Boutchko Rostyslav , Mitra Debasis , Baker Suzanne L , Jagust William J , Gullberg Grant T
Published: April 2015

The goal is to quantify the fraction of tissues that exhibit specific tracer binding in dynamic brain positron emission tomography (PET). It is achieved using a new method of dynamic image processing: clustering-initiated factor analysis (CIFA). Standard processing of such data relies on region of interest analysis and approximate models of the tracer kinetics and of tissue properties, which can degrade accuracy and reproducibility of the analysis. Clustering-initiated factor analysis allows accurate determination of the time–activity curves and spatial distributions for tissues that exhibit significant radiotracer concentration at any stage of the emission scan, including the arterial input function. We used this approach in the analysis of PET images obtained using 11C-Pittsburgh Compound B in which specific binding reflects the presence of β-amyloid. The fraction of the specific binding tissues determined using our approach correlated with that computed using the Logan graphical analysis. We believe that CIFA can be an accurate and convenient tool for measuring specific binding tissue concentration and for analyzing tracer kinetics from dynamic images for a variety of PET tracers. As an illustration, we show that four-factor CIFA allows extraction of two blood curves and the corresponding distributions of arterial and venous blood from PET images even with a coarse temporal resolution.
Real-time observation of domain fluctuations in a two-dimensional magnetic model system
Authors: Kronseder M. , Meier T. N. G. , Zimmermann M. , Buchner M. , Vogel M. , Back C. H.
Published: April 2015

Domain patterns of perpendicularly magnetized ultra-thin ferromagnetic films are often determined by the competition of the short range but strong exchange interaction favouring ferromagnetic alignment of magnetic moments and the long range but weak antiferromagnetic dipolar interaction. Detailed phase diagrams of the resulting stripe domain patterns have been evaluated in recent years; however, the domain fluctuations in these pattern forming systems have not been studied in great detail so far. Here we show that domain fluctuations can be observed in ultra-thin two-dimensional ferromagnetic Fe/Ni/Cu(001) films with perpendicular magnetization in the stripe domain phase. Non-stroboscopic time-resolved threshold photoemission electron microscopy with high temporal resolution allows analysing the dynamic fingerprint of the topological excitations in the nematic domain phase. Furthermore, proliferation of domain ending defects in the vicinity of the spin reorientation transition is witnessed.
Three-terminal heterojunction bipolar transistor solar cell for high-efficiency photovoltaic conversion
Authors: Martí A. , Luque A.
Published: April 2015

Here we propose, for the first time, a solar cell characterized by a semiconductor transistor structure (n/p/n or p/n/p) where the base–emitter junction is made of a high-bandgap semiconductor and the collector is made of a low-bandgap semiconductor. We calculate its detailed-balance efficiency limit and prove that it is the same one than that of a double-junction solar cell. The practical importance of this result relies on the simplicity of the structure that reduces the number of layers that are required to match the limiting efficiency of dual-junction solar cells without using tunnel junctions. The device naturally emerges as a three-terminal solar cell and can also be used as building block of multijunction solar cells with an increased number of junctions.
Functional Optical Coherence Tomography Enables In Vivo Physiological Assessment of Retinal Rod and Cone Photoreceptors
Authors: Zhang Qiuxiang , Lu Rongwen , Wang Benquan , Messinger Jeffrey D. , Curcio Christine A. , Yao Xincheng
Published: April 2015

Transient intrinsic optical signal (IOS) changes have been observed in retinal photoreceptors, suggesting a unique biomarker for eye disease detection. However, clinical deployment of IOS imaging is challenging due to unclear IOS sources and limited signal-to-noise ratios (SNRs). Here, by developing high spatiotemporal resolution optical coherence tomography (OCT) and applying an adaptive algorithm for IOS processing, we were able to record robust IOSs from single-pass measurements. Transient IOSs, which might reflect an early stage of light phototransduction, are consistently observed in the photoreceptor outer segment almost immediately (<4 ms) after retinal stimulation. Comparative studies of dark- and light-adapted retinas have demonstrated the feasibility of functional OCT mapping of rod and cone photoreceptors, promising a new method for early disease detection and improved treatment of diseases such as age-related macular degeneration (AMD) and other eye diseases that can cause photoreceptor damage.
Landslide susceptibility mapping using GIS-based statistical models and Remote sensing data in tropical environment
Authors: Shahabi Himan , Hashim Mazlan
Published: April 2015

This research presents the results of the GIS-based statistical models for generation of landslide susceptibility mapping using geographic information system (GIS) and remote-sensing data for Cameron Highlands area in Malaysia. Ten factors including slope, aspect, soil, lithology, NDVI, land cover, distance to drainage, precipitation, distance to fault and distance to road were extracted from SAR data, SPOT 5 and WorldView-1 images. The relationships between the detected landslide locations and these ten related factors were identified by using GIS-based statistical models including analytical hierarchy process (AHP), weighted linear combination (WLC) and spatial multi-criteria evaluation (SMCE) models. The landslide inventory map which has a total of 92 landslide locations was created based on numerous resources such as digital aerial photographs, AIRSAR data, WorldView-1 images and field surveys. Then, 80% of the landslide inventory was used for training the statistical models and the remaining 20% was used for validation purpose. The validation results using the Relative landslide density index (R-index) and Receiver operating characteristic (ROC) demonstrated that the SMCE model (accuracy is 96%) is better in prediction than AHP (accuracy is 91%) and WLC (accuracy is 89%) models. These landslide susceptibility maps would be useful for hazard mitigation purpose and regional planning.
Extraction induced by emulsion breaking as a tool for simultaneous multi-element determination in used lubricating oils by ICP-MS
Authors: He Yang-Ming , Zhao Fang-Fang , Zhou Ying , Ahmad Farooq , Ling Zhao-Xing
Published: April 2015

A novel method was developed for determination of metals in lubricating oils by ICP-MS based on extraction induced by emulsion breaking.
A combination of positive dielectrophoresis driven on-line enrichment and aptamer-fluorescent silica nanoparticle label for rapid and sensitive detection of Staphylococcus aureus
Authors: Shangguan Jingfang , Li Yuhong , He Dinggeng , He Xiaoxiao , Wang Kemin , Zou Zhen , Shi Hui
Published: April 2015

The method combining positive dielectrophoresis (pDEP) enrichment and aptamer-fluorescent silica nanoparticle label for Staphylococcus aureus detection is rapid and sensitive.
A facile strategy to adjust the density of planar triangle units in lead borate–nitrates
Authors: Song Jun-Ling , Xu Xiang , Hu Chun-Li , Kong Fang , Mao Jiang-Gao
Published: April 2015

Three novel lead(ii) borate–nitrates were obtained through a facile hydrothermal reaction by adjusting the concentrations of the starting materials.
The biocompatibility and anti-biofouling properties of magnetic core–multishell Fe@C NWs–AAO nanocomposites
Authors: Lindo André M. , Pellicer Eva , Zeeshan Muhammad A. , Grisch Roman , Qiu Famin , Sort Jordi , Sakar Mahmut S. , Nelson Bradley J. , Pané Salvador
Published: April 2015

Magnetic core–multishell Fe@C NWs–AAO nanocomposites show anti-biofouling properties while cells attach and proliferate on unfilled porous AAO.
Perovskite photovoltaics: life-cycle assessment of energy and environmental impacts
Authors: Gong Jian , Darling Seth B. , You Fengqi
Published: April 2015

Life cycle assessment of perovskite photovoltaics provides comprehensive insights into diverse environmental impacts and possible improvements in manufacturing sustainable devices.
Effect of crude oil exposure and dispersant application on meiofauna: an intertidal mesocosm experiment
Authors: Elarbaoui Soumaya , Richard Marion , Boufahja Fehmi , Mahmoudi Ezzeddine , Thomas-Guyon Hélène
Published: April 2015

Dispersant application is used as a response technique to minimize the environmental risk of an oil spill.
Hepatoprotective and urease inhibitory activities of garlic conjugated gold nanoparticles
Authors: Ateeq Muhammad , Shah Muhammad Raza , Ali Hamid , Kabir Nurul , Khan Ajmal , Nadeem Said
Published: April 2015

Garlic conjugated gold nanoparticles were successfully synthesized and their hepatoprotective potential was determined in a CCl4-induced acute hepatic injury model.
Well-oriented epitaxial gold nanotriangles and bowties on MoS2 for surface-enhanced Raman scattering
Authors: Zhou Haiqing , Yu Fang , Guo Chuan Fei , Wang Zongpeng , Lan Yucheng , Wang Gang , Fang Zheyu , Liu Yuan , Chen Shuo , Sun Lianfeng , Ren Zhifeng
Published: April 2015

Due to the lattice epitaxy between MoS2 and gold, ultrathin equilateral gold nanotriangles and bowties can be grown on layered MoS2 with favorable orientations, which further enhance the Raman signals of MoS2 greatly.
A magnonic gas sensor based on magnetic nanoparticles
Authors: Matatagui D. , Kolokoltsev O. V. , Qureshi N. , Mejía-Uriarte E. V. , Saniger J. M.
Published: April 2015

A magnonic gas sensor was developed using spin waves to detect magnetic variations in nanoparticles due to the nanoparticle–gas interaction.
Photo-fluorescent and magnetic properties of iron oxide nanoparticles for biomedical applications
Authors: Shi Donglu , Sadat M. E. , Dunn Andrew W. , Mast David B.
Published: April 2015

Iron oxide exhibits fascinating physical properties especially in the nanometer range, not only from the standpoint of basic science, but also for a variety of engineering, particularly biomedical applications.
Closed-loop ARS mode for scanning ion conductance microscopy with improved speed and stability for live cell imaging applications
Authors: Jung Goo-Eun , Noh Hanaul , Shin Yong Kyun , Kahng Se-Jong , Baik Ku Youn , Kim Hong-Bae , Cho Nam-Joon , Cho Sang-Joon
Published: April 2015

A new algorithm-based method is reported in order to control the approach speed of the nano-pipette in scanning ion conductance microscopy, thereby achieving higher imaging speed and stability.
Biodegradation of 2,4-dinitrotoluene with Rhodococcus pyridinivorans NT2: characteristics, kinetic modeling, physiological responses and metabolic pathway
Authors: Kundu Debasree , Hazra Chinmay , Chaudhari Ambalal
Published: April 2015

Physiological responses ofRhodococcus pyridinivoransNT2 and elucidation of metabolic intermediates formed during biodegradation of 2,4-DNT.
Environmentally benign synthesis of vinyl ester resin from biowaste glycerin
Authors: Shah Priyank N. , Kim Namjoon , Huang Zhuangrong , Jayamanna Mahesh , Kokil Akshay , Pine Alex , Kaltsas Jarmin , Jahngen Edwin , Ryan David K. , Yoon Seongkyu , Kovar Robert F. , Lee Yongwoo
Published: April 2015

We present here for the first time a novel environmentally benign protocol for the synthesis of vinyl ester resin (VER).
PEG-assisted hydrothermal synthesis and electrochemical performance of ZnO/Ketjenblack nanocomposite for lithium ion batteries
Authors: Chen Chao , Zhang Huang , Xu Yunlong , Ji Mandi , Dong Hui , Zhao Chongjun
Published: April 2015

A ZnO/Ketjenblack(KB) composite, exhibiting a special porous structure with ZnO particles embedded in the mesopores of KB, was fabricated. The combined KB acts as a conducting buffering matrix during the lithiation/delithiation process, improving electrochemical performance.
New insights into the microbial degradation of polyurethanes
Authors: Mahajan Neha , Gupta Pankaj
Published: April 2015

Frequent and frequently deliberate release of plastics leads to accumulation of plastic waste in the environment which is an ever increasing ecological threat.
Zwitterionic carbene adducts and their carbene isomers
Authors: Kelemen Z. , Streubel R. , Nyulászi L.
Published: April 2015

N-heterocyclic carbenes (NHC) and abnormal NHCs (aNHC) form the stable adducts,1and2, with X (CH2, SiH2, NH, PH, O, S), which are excellent nucleophiles at X.
Ruthenium nanoparticles mounted on multielement co-doped graphene: an ultra-high-efficiency cathode catalyst for Li–O2batteries
Authors: Zeng Xiaoyuan , You Chenghang , Leng Limin , Dang Dai , Qiao Xiaochang , Li Xuehui , Li Yingwei , Liao Shijun , Adzic Radoslav R.
Published: April 2015

An ultra-high performance bifunctional cathode catalyst was prepared by mounting Ru nanoparticles on multielement co-doped graphene for Li–O2batteries.
Selective activators of protein phosphatase 5 target the auto-inhibitory mechanism
Authors: Haslbeck Veronika , Drazic Adrian , Eckl Julia M. , Alte Ferdinand , Helmuth Martin , Popowicz Grzegorz , Schmidt Werner , Braun Frank , Weiwad Matthias , Fischer Gunter , Gemmecker Gerd , Sattler Michael , Striggow Frank , Groll Michael , Richter Klaus
Published: April 2015

Protein phosphatase 5 (PP5) is an evolutionary conserved serine/threonine phosphatase. Its dephosphorylation activity modulates a diverse set of cellular factors including protein kinases and the microtubule-associated tau protein involved in neurodegenerative disorders. It is auto-regulated by its heat-shock protein (Hsp90)-interacting tetratricopeptide repeat (TPR) domain and its C-terminal α-helix. In the present study, we report the identification of five specific PP5 activators [PP5 small-molecule activators (P5SAs)] that enhance the phosphatase activity up to 8-fold. The compounds are allosteric modulators accelerating efficiently the turnover rate of PP5, but do barely affect substrate binding or the interaction between PP5 and the chaperone Hsp90. Enzymatic studies imply that the compounds bind to the phosphatase domain of PP5. For the most promising compound crystallographic comparisons of the apo PP5 and the PP5–P5SA-2 complex indicate a relaxation of the auto-inhibited state of PP5. Residual electron density and mutation analyses in PP5 suggest activator binding to a pocket in the phosphatase/TPR domain interface, which may exert regulatory functions. These compounds thus may expose regulatory mechanisms in the PP5 enzyme and serve to develop optimized activators based on these scaffolds.
Suitable parameter choice on quantitative morphology of A549 cell in epithelial–mesenchymal transition
Authors: Ren Zhou-Xin , Yu Hai-Bin , Li Jian-Sheng , Shen Jun-Ling , Du Wen-Sen
Published: April 2015

Evaluation of morphological changes in cells is an integral part of study on epithelial to mesenchymal transition (EMT), however, only a few papers reported the changes in quantitative parameters and no article compared different parameters for demanding better parameters. In the study, the purpose was to investigate suitable parameters for quantitative evaluation of EMT morphological changes. A549 human lung adenocarcinoma cell line was selected for the study. Some cells were stimulated by transforming growth factor-β1 (TGF-β1) for EMT, and other cells were as control without TGF-β1 stimulation. Subsequently, cells were placed in phase contrast microscope and three arbitrary fields were captured and saved with a personal computer. Using the tools of Photoshop software, some cells in an image were selected, segmented out and exchanged into unique hue, and other part in the image was shifted into another unique hue. The cells were calculated with 29 morphological parameters by Image Pro Plus software. A parameter between cells with or without TGF-β1 stimulation was compared statistically and nine parameters were significantly different between them. Receiver operating characteristic curve (ROC curve) of a parameter was described with SPSS software and F-test was used to compare two areas under the curves (AUCs) in Excel. Among them, roundness and radius ratio were the most AUCs and were significant higher than the other parameters. The results provided a new method with quantitative assessment of cell morphology during EMT, and found out two parameters, roundness and radius ratio, as suitable for quantification.
Interleukin 34: a new modulator of human and experimental inflammatory bowel disease
Authors: Zwicker Stephanie , Martinez Gisele L. , Bosma Madeleen , Gerling Marco , Clark Reuben , Majster Mirjam , Söderman Jan , Almer Sven , Boström Elisabeth A.
Published: April 2015

IBD (inflammatory bowel disease), where CD (Crohn's disease) and UC (ulcerative colitis) represent the two main forms, are chronic inflammatory conditions of the intestine. Macrophages play a central role in IBD pathogenesis and are regulated by major differentiation factors such as CSF-1 (colony-stimulating factor 1) in homoeostasis and inflammation. IL (interleukin)-34 has recently been discovered as a second ligand for CSF-1R (CSF-1 receptor). However, expression and involvement of IL-34 in IBD remain unknown. In the present paper, we investigated the expression of IL34, CSF1 and their shared receptor CSF1R in normal human ileum and colon, in inflamed and non-inflamed tissues of CD and UC patients, and in a mouse model of experimental colitis. We found distinct expression patterns of IL34 and CSF1 in ileum and colon, with higher IL34 in ileum and, in contrast, higher CSF1 in colon. Furthermore, IL34 and CSF1 expression was increased with inflammation in IBD patients and in experimental colitis. In humans, infiltrating cells of the lamina propria and intestinal epithelial cells expressed IL-34, and TNF-α (tumour necrosis factor α) regulated IL-34 expression in intestinal epithelial cells through the NF-κB (nuclear factor κB) pathway. These data demonstrate the expression pattern of IL-34 in ileum and colon and suggest IL-34 as a new modulator of inflammation in IBD.
Adaptive 3D object registration based on point cloud distribution for mobile robot
Authors: Yoo W.S. , Park J.B. , Lee B.H.
Published: April 2015

An efficient three‐dimensional (3D) object registration method considering the point cloud distribution for a mobile robot platform is suggested. This technique adjusts overlapping areas between two consecutive scan data according to the property of the observed object's surface. The proposed technique can reduce computational load and increase the accuracy of 3D object registration with less total number of scan data. The improved performance is verified by comparing the estimated pose with the ground truth pose for observation robots.
CMOS‐based implantable glucose monitoring device with improved performance and reduced invasiveness
Authors: Kawamura T. , Masuda K. , Hirai T. , Ohta Y. , Motoyama M. , Takehara H. , Noda T. , Sasagawa K. , Tokuda T. , Okitsu T. , Takeuchi S. , Ohta J.
Published: April 2015

An implantable glucose monitoring device based on a CMOS line sensor combined with a glucose‐responsive fluorescent hydrogel is developed. An implantable glucose monitoring device with sufficient sensitivity and response time is realised, which is an improvement over the authors' previous proof‐of‐concept device. A reduction of the sensor size made the device diameter injectable with a commercially available 16‐gauge syringe needle. The sensor's performance was confirmed through both in vitro and in vivo experiments.
Multiple resource allocation in device‐to‐device communication underlaying cellular networks from an end‐to‐end energy‐efficient perspective
Authors: Xu Quansheng , Ji Hong , Li Xi
Published: April 2015

In this study, a novel energy‐efficient resource allocation (RA) scheme is proposed for device‐to‐device communication underlaying cellular networks from an end‐to‐end energy‐efficient perspective. The time slot, sub‐channel (frequency) and power resources are allocated together to optimise the energy‐efficiency (EE) performance. Furthermore, to match the practical communication situations and achieve the best EE performance, the time–frequency resource units (RUs) are used in a complete‐shared pattern. Then, the multiuser interference is very severe and complex. With all these considerations, the energy‐efficient RA problem is formulated as a mixed integer and non‐convex optimisation problem, which is an non‐deterministic polynominal (NP)‐hard problem and extremely difficult to solve. To obtain a desirable solution with a reasonable computation cost, the authors tackle this problem with two steps. Step 1, the RU allocation policy is obtained via a greedy search method, and the original optimisation problem is reduced to a non‐convex fractional programming problem. Step 2, exploiting the properties of fractional programming and after some manipulations, they transform the reduced problem to a concave optimisation problem, and obtain the sub‐optimal power allocation strategy through the Lagrange dual approach. Finally, simulation results are presented to validate the effectiveness of the proposed RA scheme.
Reconfigurable planar metamaterial unit cell
Authors: Zarghooni Behnam , Dadgarpour Abdolmehdi , Denidni Tayeb A.
Published: April 2015

A new reconfigurable metamaterial unit cell is introduced. DC‐biased controlled PIN diodes are embedded in the structure of this unit cell so that its configuration can be controlled by switching the diodes. The presented unit cell operates in two different modes. In the first mode, which is called the horizontal mode, the unit cell shows an effective permittivity and permeability close to one which leads to a refractive index around 1, whereas at the other mode, which is called vertical configuration, it possesses a double positive behaviour for the constitutive parameters and shows a refractive index of 2. Both modes are simulated using a lumped‐element model for the embedded PIN diodes and the constitutive parameters are extracted using a well‐known algorithm. To validate the results, the unit cell is fabricated and the free‐space method is used to measure the S‐parameters of the unit cell. This unit cell will be used in advanced antenna applications.
Extremely low‐frequency surface response caused by underground resource
Authors: Wang Yi , Cao Qunsheng
Published: April 2015

Electromagnetic (EM) surface responses in the extremely low‐frequency (ELF) band caused by possible underground resources are studied. Unlike traditional solutions, the authors apply the geodesic finite‐difference time domain method to simulate ELF EM wave propagation in the whole Earth (including the crust)‐ionosphere (E‐I) system to study these responses. In this way, more rigorous analysis can be achieved by simulating the complex E‐I environments, including the inhomogeneous crust and part of the ionosphere. Based on this method, they established a hypothetical model to study the effects of underground objects on received artificial signals. Through simulations, local surface responses and response perturbations caused by underground objects are studied and approximate formulas are obtained for predicting the behaviour of these responses. Finally, potential applications of the method and the results of this work are discussed.
High step‐up Z‐source DC–DC converter with coupled inductors and switched capacitor cell
Authors: Poorali Behzad , Torkan Arash , Adib Ehsan
Published: April 2015

Z‐source converter has several advantages such as high‐voltage gain, clamped switch voltage and positive output voltage polarity. This study presents a new non‐isolated high step‐up DC–DC converter which is derived from Z‐source converter and provides higher‐voltage gain compared with its conventional counterpart. Owing to its high‐voltage conversion ratio, the proposed converter is a proper choice for photovoltaic applications. Furthermore, reverse‐recovery problems caused by the output diode are reduced in the proposed converter which reduces the switching losses. In addition, the leakage energy is recycled so the conversion efficiency is improved. Analysis and operating principles of the proposed converter are discussed and design guidelines are presented. Moreover, the effect of non‐ideal elements on the proposed converter performance is analysed. A 100 W laboratory prototype to convert 20–300 V is implemented and experimental results are presented to verify theoretical analysis.
Performance analysis and capacitor design of three‐phase uncontrolled rectifier in slightly unbalanced grid
Authors: Fang Zhi‐Jian , Cai Tao , Duan Shan‐Xu , Chen Changsong , Ren Cheng‐Da
Published: April 2015

Slightly unbalanced grid voltage can cause large unbalanced current and non‐characteristic harmonics in three‐phase uncontrolled rectifier. This study proposes an accurate model to analyse the performance of three‐phase uncontrolled rectifier in slightly unbalanced grid. Three appreciative operation modes (three‐phase rectifier, double‐phase rectifier and single‐phase rectifier with discontinuous rectifier current) in slightly unbalanced grid are discussed in detail in this study. Moreover, the closed‐form analytical expressions for boundaries of modes are also derived. To further aid the designer, the curves of current unbalance, third harmonic current, output average voltage, output voltage droop and output voltage harmonic as function of loads under the condition of 2% voltage imbalance are illustrated. Then the design procedure of capacitor is given considering the influence of unbalance and harmonics in slightly unbalanced grid. Finally, a design case is expressed. The design results are realised in a 5 kW three‐phase uncontrolled rectifier to verify the accuracy of the proposed models. The proposed model provides a tool for rapidly and accurately judging the impact of various loads on the rectifier performance in slightly unbalanced grid.
Materials investigation for thermally-assisted magnetic random access memory robust against 400 °C temperatures
Authors: Annunziata A. J. , Trouilloud P. L. , Bandiera S. , Brown S. L. , Gapihan E. , O'Sullivan E. J. , Worledge D. C.
Published: April 2015

Magnetic materials are investigated in order to enable a new type of Thermally Assisted Magnetic Random Access Memory (TAS-MRAM). A TAS-MRAM materials stack that is robust against the 400 °C process temperatures required for embedded integration with complementary metal oxide silicon processes is demonstrated. In unpatterned sheet film stacks, a stable resistance-area product, tunneling magnetoresistance (MR) > 100%, and temperature-dependent exchange bias of 1500 Oe after 400 °C anneal are shown for this stack. It is further shown that by doping the sense and storage layers with Ta using thin laminations of Ta/CoFeB, the moment of each layer can be reduced by more than 40% without a major reduction in MR. In patterned nanopillar devices, it is shown that by reducing the moment of the sense and storage layers with laminations of Ta, and by adding a second MgO barrier, the resistance versus applied field loop quality is maintained, while the read field is reduced by more than 40% and devices survive 108 write cycles without breakdown or significant degradation.
Characterizing the bending and flexibility induced by bulges in DNA duplexes
Authors: Schreck John S. , Ouldridge Thomas E. , Romano Flavio , Louis Ard A. , Doye Jonathan P. K.
Published: April 2015

Advances in DNA nanotechnology have stimulated the search for simple motifs that can be used to control the properties of DNA nanostructures. One such motif, which has been used extensively in structures such as polyhedral cages, two-dimensional arrays, and ribbons, is a bulged duplex, that is, two helical segments that connect at a bulge loop. We use a coarse-grained model of DNA to characterize such bulged duplexes. We find that this motif can adopt structures belonging to two main classes: one where the stacking of the helices at the center of the system is preserved, the geometry is roughly straight, and the bulge is on one side of the duplex and the other where the stacking at the center is broken, thus allowing this junction to act as a hinge and increasing flexibility. Small loops favor states where stacking at the center of the duplex is preserved, with loop bases either flipped out or incorporated into the duplex. Duplexes with longer loops show more of a tendency to unstack at the bulge and adopt an open structure. The unstacking probability, however, is highest for loops of intermediate lengths, when the rigidity of single-stranded DNA is significant and the loop resists compression. The properties of this basic structural motif clearly correlate with the structural behavior of certain nano-scale objects, where the enhanced flexibility associated with larger bulges has been used to tune the self-assembly product as well as the detailed geometry of the resulting nanostructures. We further demonstrate the role of bulges in determining the structure of a “Z-tile,” a basic building block for nanostructures.
Design and testing of miniaturized plasma sensor for measuring hypervelocity impact plasmas
Authors: Goel A. , Tarantino P. M. , Lauben D. S. , Close S.
Published: April 2015

An increasingly notable component of the space environment pertains to the impact of meteoroids and orbital debris on spacecraft and the resulting mechanical and electrical damages. Traveling at speeds of tens of km/s, when these particles, collectively referred to as hypervelocity particles, impact a satellite, they vaporize, ionize, and produce a radially expanding plasma that can generate electrically harmful radio frequency emission or serve as a trigger for electrostatic discharge. In order to measure the flux, composition, energy distribution, and temperature of ions and electrons in this plasma, a miniaturized plasma sensor has been developed for carrying out in-situ measurements in space. The sensor comprises an array of electrostatic analyzer wells split into 16 different channels, catering to different species and energy ranges in the plasma. We present results from numerical simulation based optimization of sensor geometry. A novel approach of fabricating the sensor using printed circuit boards is implemented. We also describe the test setup used for calibrating the sensor and show results demonstrating the energy band pass characteristics of the sensor. In addition to the hypervelocity impact plasmas, the plasma sensor developed can also be used to carry out measurements of ionospheric plasma, diagnostics of plasma propulsion systems, and in other space physics experiments.
Invited Review Article: Error and uncertainty in Raman thermal conductivity measurements
Authors: Beechem Thomas , Yates Luke , Graham Samuel
Published: April 2015

Error and uncertainty in Raman thermal conductivity measurements are investigated via finite element based numerical simulation of two geometries often employed—Joule-heating of a wire and laser-heating of a suspended wafer. Using this methodology, the accuracy and precision of the Raman-derived thermal conductivity are shown to depend on (1) assumptions within the analytical model used in the deduction of thermal conductivity, (2) uncertainty in the quantification of heat flux and temperature, and (3) the evolution of thermomechanical stress during testing. Apart from the influence of stress, errors of 5% coupled with uncertainties of ±15% are achievable for most materials under conditions typical of Raman thermometry experiments. Error can increase to >20%, however, for materials having highly temperature dependent thermal conductivities or, in some materials, when thermomechanical stress develops concurrent with the heating. A dimensionless parameter—termed the Raman stress factor—is derived to identify when stress effects will induce large levels of error. Taken together, the results compare the utility of Raman based conductivity measurements relative to more established techniques while at the same time identifying situations where its use is most efficacious.
Electric field induced effects in Y3N@[C80]6− anionic solid
Authors: Sun Yong , Sezaimaru Hiroki , Sakaino Masamichi , Ogawa Naoto , Kirimoto Kenta
Published: April 2015

By measuring the i−v characteristics of Y3N@[C80]6− anionic solid at various temperatures and electric field strengths, four conducting phases with i∝v, i∝v2 with low resistance, i∝v4 and i∝v2 with high resistance were observed. First, at temperatures below 100 K and field strengths below 30 Vcm−1, the current passing through the sample was a linear function of the d.c. bias voltage due to free moving charges. Second, at the same field strengths, the trapped carrier was thermally activated with activation energies of 13.6 meV for temperature range of 100−250 K and 88.7 meV for 250−450 K. In this conducting phase, the carrier transport was governed by space charge limited conduction mechanism. Third, when the electric field increased from 30 to 120 Vcm−1, the i became a quartic function of the v because the carrier mobility is a quadratic function of the field strength. A conducting phase with high resistance was observed at temperatures below 100 K. The trapped carrier was thermally activated with activation energies of 146.5 meV for temperature range of 100−250 K and 288.5 meV for 250−450 K. Finally, in the electric field strengths of 120−2000 Vcm−1, a high resistance phase appeared in the anionic solid at temperatures below 100 K. The current was a quadratic function of the d.c. bias voltage, and the carrier mobility was independent of the field strength.
Mechanism of charge recombination in meso-structured organic-inorganic hybrid perovskite solar cells: A macroscopic perspective
Authors: Yang Wenchao , Yao Yao , Wu Chang-Qin
Published: April 2015

In the currently popular organic-inorganic hybrid perovskite solar cells, the slowness of the charge recombination processes is found to be a key factor for contributing to their high efficiencies and high open circuit voltages, but the underlying recombination mechanism remains unclear. In this work, we investigate the bimolecular recombination (BR) and the trap-assisted monomolecular recombination (MR) in meso-structured perovskite solar cells under steady state working condition, and try to reveal their roles on determining the device performance. Some interfacial effects such as the injection barriers at the selective contacts are examined as well. Based on the macroscopic device modeling, the recombination resistance-voltage (Rrec−V) and the current density-voltage (J–V) curves are calculated to characterize the recombination mechanism and describe the device performance, respectively. Through comparison with the impedance spectroscopy extracted Rrec data, it is found that under the typical BR reduction factor and deep trap densities observed in experiments, the MR dominates the charge recombination in the low voltage regime, while the BR dominates in the high voltage regime. The short circuit current and the fill factor could be reduced by the significant MR but the open circuit voltage is generally determined by the BR. The different electron injection barriers at the contact can change the BR rate and induce different patterns for the Rrec–V characteristics. For the perovskites of increased band gaps, the Rrec's are significantly enhanced, corresponding to the high open circuit voltages. Finally, it is revealed that the reduced effective charge mobility due to the transport in electron and hole transporting material makes the Rrec decrease slowly with the increasing voltage, which leads to increased open circuit voltage.