bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional inhibition of acid sphingomyelinase by Fluphenazine triggers hypoxia-specific tumor cell death
Authors: Klutzny Saskia , Lesche Ralf , Keck Matthias , Kaulfuss Stefan , Schlicker Andreas , Christian Sven , Sperl Carolyn , Neuhaus Roland , Mowat Jeffrey , Steckel Michael , Riefke Björn , Prechtl Stefan , Parczyk Karsten , Steigemann Patrick
Published: March 2017

Owing to lagging or insufficient neo-angiogenesis, hypoxia is a feature of most solid tumors. Hypoxic tumor regions contribute to resistance against antiproliferative chemotherapeutics, radiotherapy and immunotherapy. Targeting cells in hypoxic tumor areas is therefore an important strategy for cancer treatment. Most approaches for targeting hypoxic cells focus on the inhibition of hypoxia adaption pathways but only a limited number of compounds with the potential to specifically target hypoxic tumor regions have been identified. By using tumor spheroids in hypoxic conditions as screening system, we identified a set of compounds, including the phenothiazine antipsychotic Fluphenazine, as hits with novel mode of action. Fluphenazine functionally inhibits acid sphingomyelinase and causes cellular sphingomyelin accumulation, which induces cancer cell death specifically in hypoxic tumor spheroids. Moreover, we found that functional inhibition of acid sphingomyelinase leads to overactivation of hypoxia stress-response pathways and that hypoxia-specific cell death is mediated by the stress-responsive transcription factor ATF4. Taken together, the here presented data suggest a novel, yet unexplored mechanism in which induction of sphingolipid stress leads to the overactivation of hypoxia stress-response pathways and thereby promotes their pro-apoptotic tumor-suppressor functions to specifically kill cells in hypoxic tumor areas.
The role of autophagy in asparaginase-induced immune suppression of macrophages
Authors: Song Ping , Wang Ziyu , Zhang Xuyao , Fan Jiajun , Li Yubin , Chen Qicheng , Wang Shaofei , Liu Peipei , Luan Jingyun , Ye Li , Ju Dianwen
Published: March 2017

Erwinia asparaginase, a bacteria-derived enzyme drug, has been used in the treatment of various cancers, especially acute lymphoblastic leukemia (ALL). One of the most significant side effects associated with asparaginase administration is immune suppression, which limits its application in clinic. Macrophages are phagocytic immune cells and have a central role in inflammation and host defense. We reported here that asparaginase disturbed the function of macrophages including phagocytosis, proliferation, ROS and nitric oxide secretion, interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) secretion, and major histocompatibility complex II (MHC-II) molecule expression, thus induced immune suppression in interferon-γ and lipopolysaccharide-stimulated macrophages. We also observed that asparaginase inhibited autophagy in macrophages via activating Akt/mTOR and suppressing Erk1/2 signaling pathway as evidenced by less formation of autophagosomes, downregulation of autophagy-related protein LC3-II, and decreased number of autophagy-like vacuoles. Further study discovered that treatment with autophagy inhibitor 3-MA in place of asparaginase on activated macrophages could also downregulate phagocytosis, cytokine secretion, and MHC-II expression. Moreover, incubation with autophagy inducer trehalose restored the capacity of phagocytosis, IL-6 and TNF-α secretion, and MHC-II expression in macrophages. These results prove the important role of autophagy in the function of macrophages, and activation of autophagy can overcome asparaginase-induced immune suppression in macrophages.
Pressure modulates the self-cleavage step of the hairpin ribozyme
Authors: Schuabb Caroline , Kumar Narendra , Pataraia Salome , Marx Dominik , Winter Roland
Published: March 2017

The ability of certain RNAs, denoted as ribozymes, to not only store genetic information but also catalyse chemical reactions gave support to the RNA world hypothesis as a putative step in the development of early life on Earth. This, however, might have evolved under extreme environmental conditions, including the deep sea with pressures in the kbar regime. Here we study pressure-induced effects on the self-cleavage of hairpin ribozyme by following structural changes in real-time. Our results suggest that compression of the ribozyme leads to an accelerated transesterification reaction, being the self-cleavage step, although the overall process is retarded in the high-pressure regime. The results reveal that favourable interactions between the reaction site and neighbouring nucleobases are strengthened under pressure, resulting therefore in an accelerated self-cleavage step upon compression. These results suggest that properly engineered ribozymes may also act as piezophilic biocatalysts in addition to their hitherto known properties.
Recombinant tandem of pore-domains in a Weakly Inward rectifying K+ channel 2 (TWIK2) forms active lysosomal channels
Authors: Bobak Nicole , Feliciangeli Sylvain , Chen Cheng-Chang , Ben Soussia Ismail , Bittner Stefan , Pagnotta Sophie , Ruck Tobias , Biel Martin , Wahl-Schott Christian , Grimm Christian , Meuth Sven G. , Lesage Florian
Published: March 2017

Recombinant TWIK2 channels produce weak basal background K+ currents. Current amplitudes depend on the animal species the channels have been isolated from and on the heterologous system used for their re-expression. Here we show that this variability is due to a unique cellular trafficking. We identified three different sequence signals responsible for the preferential expression of TWIK2 in the Lamp1-positive lysosomal compartment. Sequential inactivation of tyrosine-based (Y308ASIP) and di-leucine-like (E266LILL and D282EDDQVDIL) trafficking motifs progressively abolishes the targeting of TWIK2 to lysosomes, and promotes its functional relocation at the plasma membrane. In addition, TWIK2 contains two N-glycosylation sites (N79AS and N85AS) on its luminal side, and glycosylation is necessary for expression in lysosomes. As shown by electrophysiology and electron microscopy, TWIK2 produces functional background K+ currents in the endolysosomes, and its expression affects the number and mean size of the lysosomes. These results show that TWIK2 is expressed in lysosomes, further expanding the registry of ion channels expressed in these organelles.
Synthesis and Characterization of Porous MnCo2O4 for Electrochemical Determination of Cadmium ions in Water Samples
Authors: Velmurugan Murugan , Chen Shen-Ming
Published: March 2017

To utilize the maximum activity of nanomaterials, it was specifically synthesized by appropriate physicochemical properties. In that aspect, we have described the synthesis of porous MnCo2O4 by simple chemical route and applied for the selective detection of cadmium (Cd (II)). The as-prepared porous MnCo2O4 was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) adsorption isotherm, X-ray diffraction pattern analysis (XRD), Fourier transform infra-red spectroscopy (FT-IR), energy dispersive X-ray (EDX) and electrochemical techniques. The porous MnCo2O4 exhibited an excellent electrochemical behaviour and good analytical response towards the determination of Cd (II). Those analytical factors such as pH, deposition potential and deposition time are optimized by using differential pulse anodic stripping voltammetry (DPASV). A wide linear concentration range from 2.3 to 120 µg L−1, limit of detection (LOD) of 0.72 µg L−1 and the limit of quantification (LOQ) of 0.91 µg L−1 were achieved for determination of Cd (II). The selectivity of the developed sensor was explored in the presence of co-interfering ions. Also our sensor exhibits a good stability, reproducibility and repeatability. In addition, the practicability of proposed sensor was evaluated for the detection of Cd (II) in real water samples.
Spatial and molecular resolution of diffuse malignant mesothelioma heterogeneity by integrating label-free FTIR imaging, laser capture microdissection and proteomics
Authors: Großerueschkamp Frederik , Bracht Thilo , Diehl Hanna C. , Kuepper Claus , Ahrens Maike , Kallenbach-Thieltges Angela , Mosig Axel , Eisenacher Martin , Marcus Katrin , Behrens Thomas , Brüning Thomas , Theegarten Dirk , Sitek Barbara , Gerwert Klaus
Published: March 2017

Diffuse malignant mesothelioma (DMM) is a heterogeneous malignant neoplasia manifesting with three subtypes: epithelioid, sarcomatoid and biphasic. DMM exhibit a high degree of spatial heterogeneity that complicates a thorough understanding of the underlying different molecular processes in each subtype. We present a novel approach to spatially resolve the heterogeneity of a tumour in a label-free manner by integrating FTIR imaging and laser capture microdissection (LCM). Subsequent proteome analysis of the dissected homogenous samples provides in addition molecular resolution. FTIR imaging resolves tumour subtypes within tissue thin-sections in an automated and label-free manner with accuracy of about 85% for DMM subtypes. Even in highly heterogeneous tissue structures, our label-free approach can identify small regions of interest, which can be dissected as homogeneous samples using LCM. Subsequent proteome analysis provides a location specific molecular characterization. Applied to DMM subtypes, we identify 142 differentially expressed proteins, including five protein biomarkers commonly used in DMM immunohistochemistry panels. Thus, FTIR imaging resolves not only morphological alteration within tissue but it resolves even alterations at the level of single proteins in tumour subtypes. Our fully automated workflow FTIR-guided LCM opens new avenues collecting homogeneous samples for precise and predictive biomarkers from omics studies.
Epidemic trend of periodontal disease in elderly Chinese population, 1987–2015: a systematic review and meta-analysis
Authors: Yang Hongmei , Xiao Li , Zhang Lei , Deepal Stacytabi , Ye Guo , Zhang Xiaonan
Published: March 2017

Periodontal disease is a common oral health problem in the elderly population. The prevalence varied substantially due to absence of a universal diagnostic criteria. We conducted a systematic review to identify the epidemiological characteristics of periodontal diseases among Chinese elderly people. A total of 19 articles were included. The pooled detection rates for three indicators, including bleeding on probing (BOP), pocket depth (PD) and clinical attachment loss (CAL), were 53.9% (95% CI: 43.8–63.9%), 57.0% (50.8–63.2%), and 70.1% (65.4–74.8%), respectively. No significant differences in these indicators between urban and rural population. When stratified by gender, BOP (+) detection rates did not show any differences, but the detection rates of PD ≥ 4 mm and CAL ≥ 4 mm were significantly higher in males than in females (59.3% [53.4–65.2%] versus 50.8% [43.5–58.0%], RRPD = 1.13 [1.01–1.26]; 73.8% [70.0–77.7%] versus 65.2% [60.2–70.2%], RRCAL = 1.21 [1.11–1.32]). No statistically significant differences were observed between CAL ≥ 4 mm and PD ≥ 4 mm (RR = 1.12, [0.83–1.50]). A geographical map based on available data during 1987–2015 showed wide variations of periodontal disease across the mainland China. Some factors such as heterogeneity of case definitions, no specific diagnosis of periodontitis, and variable quality of the included studies could affect the final results. Hence, further high-quality epidemiological studies with standardized diagnostic criteria are needed.
A pilot study on transient ischemic stroke induced with endothelin-1 in the rhesus monkeys
Authors: Dai PeiMin , Huang Hui , Zhang Lin , He Jing , Zhao XuDong , Yang FuHan , Zhao Ning , Yang JianZhen , Ge LongJiao , Lin Yu , Yu HuaLin , Wang JianHong
Published: March 2017

Endothelin-1 (ET-1), a vasoconstrictor, has recently been used to induce focal ischemia in rodents and marmoset monkeys. The rhesus monkey, however, has numerous advantages to the rodent and marmoset that make it a superior and irreplaceable animal model for studying stroke in the brain. In the present study, after mapping the preferred hand representation in two healthy male monkeys with intracortical micro-stimulation, ET-1 was microinjected into the contralateral motor cortex (M1) to its preferred hand. The monkeys had been trained in three manual dexterity tasks before the microinjection and were tested for these tasks following the ET-1 injection. Brain Magnetic Resonance Imaging scans were performed 1, 7, 14 and 28 days post ischemia. It was found that ET-1 impaired the manual dexterity of the monkeys in the vertical slot and rotating Brinkman board tasks 3–8 days after the injection. Brain imaging found that severe edema was present 7 days after the focal ischemia. This data suggest that ET-1 can induce transient ischemic stroke in rhesus monkey and that ET-1 induced focal ischemia in non-human primates is a potential model to study the mechanism of stroke and brain repair after stroke.
A Hierarchical Feature and Sample Selection Framework and Its Application for Alzheimer’s Disease Diagnosis
Authors: An Le , Adeli Ehsan , Liu Mingxia , Zhang Jun , Lee Seong-Whan , Shen Dinggang
Published: March 2017

Classification is one of the most important tasks in machine learning. Due to feature redundancy or outliers in samples, using all available data for training a classifier may be suboptimal. For example, the Alzheimer’s disease (AD) is correlated with certain brain regions or single nucleotide polymorphisms (SNPs), and identification of relevant features is critical for computer-aided diagnosis. Many existing methods first select features from structural magnetic resonance imaging (MRI) or SNPs and then use those features to build the classifier. However, with the presence of many redundant features, the most discriminative features are difficult to be identified in a single step. Thus, we formulate a hierarchical feature and sample selection framework to gradually select informative features and discard ambiguous samples in multiple steps for improved classifier learning. To positively guide the data manifold preservation process, we utilize both labeled and unlabeled data during training, making our method semi-supervised. For validation, we conduct experiments on AD diagnosis by selecting mutually informative features from both MRI and SNP, and using the most discriminative samples for training. The superior classification results demonstrate the effectiveness of our approach, as compared with the rivals.
High Speed Computational Ghost Imaging via Spatial Sweeping
Authors: Wang Yuwang , Liu Yang , Suo Jinli , Situ Guohai , Qiao Chang , Dai Qionghai
Published: March 2017

Computational ghost imaging (CGI) achieves single-pixel imaging by using a Spatial Light Modulator (SLM) to generate structured illuminations for spatially resolved information encoding. The imaging speed of CGI is limited by the modulation frequency of available SLMs, and sets back its practical applications. This paper proposes to bypass this limitation by trading off SLM’s redundant spatial resolution for multiplication of the modulation frequency. Specifically, a pair of galvanic mirrors sweeping across the high resolution SLM multiply the modulation frequency within the spatial resolution gap between SLM and the final reconstruction. A proof-of-principle setup with two middle end galvanic mirrors achieves ghost imaging as fast as 42 Hz at 80 × 80-pixel resolution, 5 times faster than state-of-the-arts, and holds potential for one magnitude further multiplication by hardware upgrading. Our approach brings a significant improvement in the imaging speed of ghost imaging and pushes ghost imaging towards practical applications.
Spin filtering effect generated by the inter-subband spin-orbit coupling in the bilayer nanowire with the quantum point contact
Authors: Wójcik Paweł , Adamowski Janusz
Published: March 2017

The spin filtering effect in the bilayer nanowire with quantum point contact is investigated theoretically. We demonstrate the new mechanism of the spin filtering based on the lateral inter-subband spin-orbit coupling, which for the bilayer nanowires has been reported to be strong. The proposed spin filtering effect is explained as the joint effect of the Landau-Zener intersubband transitions caused by the hybridization of states with opposite spin (due to the lateral Rashba SO interaction) and the confinement of carriers in the quantum point contact region.
Phosphatidylinositol (4,5)-bisphosphate dynamically regulates the K2P background K+ channel TASK-2
Authors: Niemeyer María Isabel , Cid L. Pablo , Paulais Marc , Teulon Jacques , Sepúlveda Francisco V.
Published: March 2017

Two-pore domain K2P K+ channels responsible for the background K+ conductance and the resting membrane potential, are also finely regulated by a variety of chemical, physical and physiological stimuli. Hormones and transmitters acting through Gq protein-coupled receptors (GqPCRs) modulate the activity of various K2P channels but the signalling involved has remained elusive, in particular whether dynamic regulation by membrane PI(4,5)P2, common among other classes of K+ channels, affects K2P channels is controversial. Here we show that K2P K+ channel TASK-2 requires PI(4,5)P2 for activity, a dependence that accounts for its run down in the absence of intracellular ATP and its full recovery by addition of exogenous PI(4,5)P2, its inhibition by low concentrations of polycation PI scavengers, and inhibition by PI(4,5)P2 depletion from the membrane. Comprehensive mutagenesis suggests that PI(4,5)P2 interaction with TASK-2 takes place at C-terminus where three basic aminoacids are identified as being part of a putative binding site.
HIVed, a knowledgebase for differentially expressed human genes and proteins during HIV infection, replication and latency
Authors: Li Chen , Ramarathinam Sri H. , Revote Jerico , Khoury Georges , Song Jiangning , Purcell Anthony W.
Published: March 2017

Measuring the altered gene expression level and identifying differentially expressed genes/proteins during HIV infection, replication and latency is fundamental for broadening our understanding of the mechanisms of HIV infection and T-cell dysfunction. Such studies are crucial for developing effective strategies for virus eradication from the body. Inspired by the availability and enrichment of gene expression data during HIV infection, replication and latency, in this study, we proposed a novel compendium termed HIVed (HIV expression database; http://hivlatency.erc.monash.edu/) that harbours comprehensive functional annotations of proteins, whose genes have been shown to be dysregulated during HIV infection, replication and latency using different experimental designs and measurements. We manually curated a variety of third-party databases for structural and functional annotations of the protein entries in HIVed. With the goal of benefiting HIV related research, we collected a number of biological annotations for all the entries in HIVed besides their expression profile, including basic protein information, Gene Ontology terms, secondary structure, HIV-1 interaction and pathway information. We hope this comprehensive protein-centric knowledgebase can bridge the gap between the understanding of differentially expressed genes and the functions of their protein products, facilitating the generation of novel hypotheses and treatment strategies to fight against the HIV pandemic.
High-performance nanotube-enhanced perovskite photodetectors
Authors: Ka Ibrahima , Gerlein Luis Felipe , Nechache Riad , Cloutier Sylvain G.
Published: March 2017

Organic-inorganic perovskites have already shown a tremendous potential for low-cost light-harvesting devices. Yet, the relatively low carrier mobilities in bulk perovskites still prevent large-area devices with performances competing with state-of-the-art technologies. Here, we tackle this fundamental challenge by incorporating single-wall carbon nanotubes within a perovskite matrix by means of a simple two-step method in ambient air. Using this nano-engineered hybrid film, we demonstrate large-area photodetectors with responsivities up-to 13.8 A.W−1 and a broad spectral response from 300 to 800 nm, indicating that photocurrent generation arises from the charge transfer from the perovskite matrix to the embedded nanotube network. As the nanotubes facilitate the carrier extraction, these photodetectors also show a fast response time of 10 ms. This is significantly faster than most of previous reports on perovskite-based photodetectors, including devices with much smaller photosensitive areas. This approach is also well-suited for large-scale production of other perovskite-based light-harvesting devices.
Differentiation of Pancreatic Cyst Types by Analysis of Rheological Behavior of Pancreatic Cyst Fluid
Authors: Khamaysi Iyad , Abu Ammar Aiman , Vasilyev Gleb , Arinstein Arkadii , Chowers Yehuda , Zussman Eyal
Published: March 2017

Differentiation between mucinous and non-mucinous pancreatic cysts is exceedingly important and challenging, particularly as the former bears malignant transformation potential. Pancreatic cyst fluid (PCF)-based diagnostics, including analyses of biochemical markers, as well as cytology, has shown inadequate accuracy. Herein, a preliminary single-center study of 22 PCF samples, collected by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), assessed the rheological behavior of PCF and its correlation with lesion type. The dependence of PCF shear viscosity on shear rate was found to follow a power law and could be fitted using Ostwald–de Waele model. Three types of flow curves were identified, where two types correlated with non-mucinous cysts, differing by their power law exponent, and the third type corresponding to mucinous cysts. Viscosity measured at a high shear rate was shown to serve as an accurate and independent marker distinguishing between mucinous and non-mucinous cysts, with an optimal cutoff value of ηc = 1.3 cP The accuracy of this novel technique proved superior to string-sign, cytology, carcinoembryonic antigen, and amylase assessments. Moreover, the combined predictive value of ηc and patient age provided for sensitivity and specificity of 100% and 95.5%, respectively. This simple and rapid diagnostic tool can be immediately implemented after EUS-FNA sampling.
Photostability of plasma polymerized γ-terpinene thin films for encapsulation of OPV
Authors: Bazaka Kateryna , Ahmad Jakaria , Oelgemöller Michael , Uddin Ashraf , Jacob Mohan V.
Published: March 2017

Optically transparent, smooth, defect-free, chemically inert and with good adhesion to a variety of substrates, plasma polymers from plant-derived secondary metabolites have been identified as promising encapsulating materials for organic electronics and photovoltaics. Here, we demonstrate that an encapsulating layer of plasma polymerized γ-terpinene reduces degradation-related loss in conversion efficiency in PCPDTBT:PC70BM solar cells under ambient operating conditions. The stability of γ-terpinene films was then investigated under extreme UV irradiation conditions as a function of deposition power. When exposed to ambient air, prolonged exposure to UV–A and UV–B light led to notable ageing of the polymer. Photooxidation was identified as the main mechanism of degradation, confirmed by significantly slower ageing when oxygen was restricted through the use of a quartz cover. Under unnatural high-energy UV–C irradiation, significant photochemical degradation and oxidation occurred even in an oxygen-poor environment.
Fluorescent nanodiamonds enable quantitative tracking of human mesenchymal stem cells in miniature pigs
Authors: Su Long-Jyun , Wu Meng-Shiue , Hui Yuen Yung , Chang Be-Ming , Pan Lei , Hsu Pei-Chen , Chen Yit-Tsong , Ho Hong-Nerng , Huang Yen-Hua , Ling Thai-Yen , Hsu Hsao-Hsun , Chang Huan-Cheng
Published: March 2017

Cell therapy is a promising strategy for the treatment of human diseases. While the first use of cells for therapeutic purposes can be traced to the 19th century, there has been a lack of general and reliable methods to study the biodistribution and associated pharmacokinetics of transplanted cells in various animal models for preclinical evaluation. Here, we present a new platform using albumin-conjugated fluorescent nanodiamonds (FNDs) as biocompatible and photostable labels for quantitative tracking of human placenta choriodecidual membrane-derived mesenchymal stem cells (pcMSCs) in miniature pigs by magnetic modulation. With this background-free detection technique and time-gated fluorescence imaging, we have been able to precisely determine the numbers as well as positions of the transplanted FND-labeled pcMSCs in organs and tissues of the miniature pigs after intravenous administration. The method is applicable to single-cell imaging and quantitative tracking of human stem/progenitor cells in rodents and other animal models as well.
Reactive Hyperemia Index in Patients on Maintenance Hemodialysis: Cross-sectional Data from a Cohort Study
Authors: Liu Wenjin , Meng Meijuan , Chen Jianping , Wang Liang , Sun Zhuxing , Li Xiurong , Zhou Jianmei , Gao Chaoqing , Zhou Jiajun , Chu Hong , Fan Wei , Bai Youwei , Yang Junwei
Published: March 2017

Previous studies suggested that the reactive hyperemia index (RHI) is a promising cardiovascular risk predictor. We aimed to evaluate clinical determinants of RHI and its association with circulating endothelial injury and cardiac markers in hemodialysis patients. Among 368 patients recruited, RHI was evaluated by peripheral arterial tonometry (PAT) on a midweek nondialysis day. Clinical determinants of RHI were explored by multiple stepwise regression analysis and associations between RHI and circulating markers were evaluated by general linear models. The major cause of a failed PAT test was poor signal (82.1%). Intraclass correlation coefficient for reproducibility evaluation was 0.74. Multiple regression analysis showed traditional clinical factors only explained 7% of the variance of natural logarithm RHI (LnRHI) in the patients. In association analyses, LnRHI showed significant positive associations with Von Willebrand factor (vWF) (p = 0.04) and tissue factor (p = 0.047). It also associated positively with troponins (p ≤ 0.02 for both). In conclusion, performance of the PAT test was acceptable in dialysis patients and traditional clinical variables had very limited influence on RHI in these subjects. Among a panel of conventional endothelial injury markers, RHI showed very modest associations with only vWF and tissue factor. RHI associated positively with troponins in the patients.
An ultrasensitive “turn-off” SERS sensor for quantitatively detecting heparin based on 4-mercaptobenzoic acid functionalized gold nanoparticles
Authors: Zhang Chenmeng , Liang Xiu , You Tingting , Yang Nan , Gao Yukun , Yin Penggang
Published: March 2017

We develop an ultrasensitive “turn off” Surface Enhanced Raman Spectroscopy (SERS) sensor for the detection of heparin based on the anti-aggregation of 4-mercaptobenzoic acid stabilized gold nanoparticles.
Enhancing MRI of liver metastases with a zwitterionized biodegradable dendritic contrast agent
Authors: Zhou Xiaoxuan , Ye Mingzhou , Han Yuxin , Tang Jianbin , Qian Yue , Hu Hongjie , Shen Youqing
Published: March 2017

The MRI enhanced by a zwitterionized dendritic contrast agent clearly indicates metastatic tumors in the liver.
Direct copper-catalyzed oxidative trifluoromethylthiolation of aryl boronic acids with AgSCF3
Authors: Wu Wei , Wang Biyun , Ji Xinfei , Cao Song
Published: March 2017

A copper-catalyzed direct oxidative trifluoromethylthiolation of aryl boronic acids with AgSCF3 has been developed.
Study of dielectric relaxation and thermally activated a.c. conduction in lead containing topological glassy semiconductors
Authors: Sharma Arvind , Mehta N.
Published: March 2017

Illustration of CBH model of the Coulombic well.
PRAP-CVD: how to design high conformal PEDOT surfaces
Authors: Pistillo B. R. , Menguelti K. , Arl D. , Addiego F. , Lenoble D.
Published: March 2017

Deposition of conformal polymer thin layers is a key point for many applications where a high surface area is required. PRAP-CVD is emerging as an efficient technique to synthesise and deposit conjugated polymers on 3D complex shape substrates.
Electronic structure and multi-scale behaviour for the dislocation–doping complex in the gamma phase of nickel-base superalloys
Authors: Liu Feng-Hua , Wang Chong-Yu
Published: March 2017

By using the lattice Green-function multiscale method, the equilibrium geometry of the edge dislocation in the γ matrix was obtained and the electronic structure changes due to the addition of refractory elements Re, W and Ta were analysed.
High energy density supercapacitors composed of nickel cobalt oxide nanosheets on nanoporous carbon nanoarchitectures
Authors: Young Christine , Salunkhe Rahul R. , Alshehri Saad M. , Ahamad Tansir , Huang Zhenguo , Henzie Joel , Yamauchi Yusuke
Published: March 2017

This work demonstrates a simple approach to the development of NiCo2O4 and nanoporous carbon composites for high-performance supercapacitor application.
A general approach to synthesise ultrathin NiM (M = Fe, Co, Mn) hydroxide nanosheets as high-performance low-cost electrocatalysts for overall water splitting
Authors: Sun Xiuhui , Shao Qi , Pi Yecan , Guo Jun , Huang Xiaoqing
Published: March 2017

A general approach to ultrathin NiM (M = Fe, Co, Mn) hydroxide nanosheets as efficient electrocatalysts for overall water splitting.
Structural characterization and enhanced luminescence of Eu-doped 2CeO2–0.5La2O3composite phosphor powders by a facile solution combustion synthesis
Authors: Shi Shikao , Li Keyan , Wang Shuping , Zong Ruilong , Zhang Guanglei
Published: March 2017

When Eu3+occupied Ce4+rather than the La3+site, the Ce2LaO5.5:Eu3+composite exhibited remarkably enhanced luminescence as compared with CeO2:Eu3+.
Rice husk-based hierarchically porous carbon and magnetic particles composites for highly efficient electromagnetic wave attenuation
Authors: Fang Jiyong , Shang Yingshuang , Chen Zheng , Wei Wei , Hu Ying , Yue Xigui , Jiang Zhenhua
Published: March 2017

For RHPC/Fe, RL of −21.8 dB can be achieved with the absorption bandwidth (RL ≤ −10 dB, ABW) of 5.6 GHz at a thickness of 1.4 mm, while for RHPC/Co, RL of −40.1 dB can be achieved with ABW of 2.7 GHz at a thickness of 1.8 mm.
Smart approach to liquid electrolyte-based multi-colored electrochemiluminescence for lighting applications
Authors: Kim J. Y. , Cheon S. , Lee H. , Oh J.-Y. , Lee J.-I. , Ryu H. , Kim Y.-H. , Hwang C.-S.
Published: March 2017

As potential lighting-emitting devices, electrochemiluminescence (ECL) devices are promising in terms of device structure and fabrication and involve low processing cost compared to organic light-emitting devices (OLEDs).
Structural basis of molecular recognition of helical histone H3 tail by PHD finger domains
Authors: Bortoluzzi Alessio , Amato Anastasia , Lucas Xavier , Blank Manuel , Ciulli Alessio
Published: March 2017

The plant homeodomain (PHD) fingers are among the largest family of epigenetic domains, first characterized as readers of methylated H3K4. Readout of histone post-translational modifications by PHDs has been the subject of intense investigation; however, less is known about the recognition of secondary structure features within the histone tail itself. We solved the crystal structure of the PHD finger of the bromodomain adjacent to zinc finger 2A [BAZ2A, also known as TIP5 (TTF-I/interacting protein 5)] in complex with unmodified N-terminal histone H3 tail. The peptide is bound in a helical folded-back conformation after K4, induced by an acidic patch on the protein surface that prevents peptide binding in an extended conformation. Structural bioinformatics analyses identify a conserved Asp/Glu residue that we name ‘acidic wall’, found to be mutually exclusive with the conserved Trp for K4Me recognition. Neutralization or inversion of the charges at the acidic wall patch in BAZ2A, and homologous BAZ2B, weakened H3 binding. We identify simple mutations on H3 that strikingly enhance or reduce binding, as a result of their stabilization or destabilization of H3 helicity. Our work unravels the structural basis for binding of the helical H3 tail by PHD fingers and suggests that molecular recognition of secondary structure motifs within histone tails could represent an additional layer of regulation in epigenetic processes.
Mobile ultrasonic transducer positioning
Authors: Khyam Mohammad Omar , Ge Shuzhi Sam , Xinde Li , Pickering Mark
Published: March 2017

For positioning a moving ultrasonic transmitter, most of the existing ultrasonic positioning systems require the use of a bank of correlators to estimate the Doppler shift associated with its movement which require high computational complexity. In this paper, for positioning a moving transmitter, a computationally efficient a Doppler shift estimation and compensation technique is proposed. As the proposed approach has the ability to measure the Doppler shift directly from the received signal, it does not require to use a bank of correlators to estimate the Doppler shift associated with its movement of the transmitter.
Green preparation of Ag nanoparticles/graphite nanosheets composite
Authors: Gan Xinxin , Xue Feng , Ding Enyong
Published: March 2017

A simple chemical edge doping method to prepare the Ag nanoparticles/graphite nanosheets (Ag/GNS) composite is presented. The GNS were fabricated in water with the assistance of a high pressure homogenisation (HPH). Ag nanoparticles (Ag‐NPs) were decorated on GNS by edge doping. HPH was proved to be an efficient way to fabricate GNS with active sites to anchor metal nanoparticles in the authors’ work. The Ag/GNS composite synthesised by edge doping barely had any defects. The average diameter of the Ag‐NPs in this case was 52.6 nm. It was observed that the fabricated Ag‐NPs distributed mainly on the edge of GNS where the active sites were. The Ag/GNS composite exhibited a distinct surface‐enhanced Raman scattering effect with a low concentration of silver. The Ag‐NPs on the composite had improved stability (up to a month). It is believed that this simple and green method of nanocomposite preparation will shed some lights on the large‐scale production of metal‐nanoparticles‐decorated carbon matrices.
Edge effect enhanced photo-thermionic emission from a carbon nanotubes array
Authors: Li Chi , Li Zhenjun , Chen Ke , Bai Bing , Dai Qing
Published: March 2017

Employing optical field enhancement at the edges of the nanostructures, an enhanced photo-thermionic emission (PTE) was obtained from a well-defined carbon nanotube (CNT) cluster array. Compared with the un-patterned carbon nanotube film, the PTE from the CNT cluster array was enhanced 10 times at the same laser intensity. The concept was proved by the computer simulation as well. We believe that an edge effect enhanced CNT PTE emitter is of great potential for application in next-generation portable and inexpensive vacuum electronic devices.
FCS experiments to quantify Ca2+ diffusion and its interaction with buffers
Authors: Sigaut Lorena , Villarruel Cecilia , Ponce Dawson Silvina
Published: March 2017

Ca2+ signals are ubiquitous. One of the key factors for their versatility is the variety of spatio-temporal distributions that the cytosolic Ca2+ can display. In most cell types Ca2+ signals not only depend on Ca2+ entry from the extracellular medium but also on Ca2+ release from internal stores, a process which is in turn regulated by cytosolic Ca2+ itself. The rate at which Ca2+ is transported, the fraction that is trapped by intracellular buffers, and with what kinetics are thus key features that affect the time and spatial range of action of Ca2+ signals. The quantification of Ca2+ diffusion in intact cells is quite challenging because the transport rates that can be inferred using optical techniques are intricately related to the interaction of Ca2+ with the dye that is used for its observation and with the cellular buffers. In this paper, we introduce an approach that uses Fluorescence Correlation Spectroscopy (FCS) experiments performed at different conditions that in principle allows the quantification of Ca2+ diffusion and of its reaction rates with unobservable (non-fluorescent) Ca2+ buffers. To this end, we develop the necessary theory to interpret the experimental results and then apply it to FCS experiments performed in a set of solutions containing Ca2+, a single wavelength Ca2+ dye, and a non-fluorescent Ca2+ buffer. We show that a judicious choice of the experimental conditions and an adequate interpretation of the fitting parameters can be combined to extract information on the free diffusion coefficient of Ca2+ and of some of the properties of the unobservable buffer. We think that this approach can be applied to other situations, particularly to experiments performed in intact cells.
Magnetic gaps in organic tri-radicals: From a simple model to accurate estimates
Authors: Barone Vincenzo , Cacelli Ivo , Ferretti Alessandro , Prampolini Giacomo
Published: March 2017

The calculation of the energy gap between the magnetic states of organic poly-radicals still represents a challenging playground for quantum chemistry, and high-level techniques are required to obtain accurate estimates. On these grounds, the aim of the present study is twofold. From the one side, it shows that, thanks to recent algorithmic and technical improvements, we are able to compute reliable quantum mechanical results for the systems of current fundamental and technological interest. From the other side, proper parameterization of a simple Hubbard Hamiltonian allows for a sound rationalization of magnetic gaps in terms of basic physical effects, unraveling the role played by electron delocalization, Coulomb repulsion, and effective exchange in tuning the magnetic character of the ground state. As case studies, we have chosen three prototypical organic tri-radicals, namely, 1,3,5-trimethylenebenzene, 1,3,5-tridehydrobenzene, and 1,2,3-tridehydrobenzene, which differ either for geometric or electronic structure. After discussing the differences among the three species and their consequences on the magnetic properties in terms of the simple model mentioned above, accurate and reliable values for the energy gap between the lowest quartet and doublet states are computed by means of the so-called difference dedicated configuration interaction (DDCI) technique, and the final results are discussed and compared to both available experimental and computational estimates.
Design of zero index metamaterials with PT symmetry using epsilon-near-zero media with defects
Authors: Fu Yangyang , Zhang Xiaojing , Xu Yadong , Chen Huanyang
Published: March 2017

Inspired by the design of matched zero-index metamaterials (ZIMs) using defects in epsilon-near-zero (ENZ) media, we demonstrate in this letter that ZIMs with parity-time (PT) symmetry in a waveguide system can be achieved by introducing defects with loss/gain inside ENZ media. Such results are well verified from the phenomenon of unidirectional transparency, corresponding to the exceptional points in PT symmetric systems. Moreover, by changing the geometry configuration of ENZ, the effective loss/gain in the structure composed of ENZ and defects can be amplified immensely by virtue of the resonances of defects. Therefore, our work also provides a blueprint for obtaining amplified loss/gain in PT symmetric systems.
Temperature fluctuations and the thermodynamic determination of the cooperativity length in glass forming liquids
Authors: Chua Y. Z. , Zorn R. , Holderer O. , Schmelzer J. W. P. , Schick C. , Donth E.
Published: March 2017

The aim of this paper is to decide which of the two possible thermodynamic expressions for the cooperativity length in glass forming liquids is the correct one. In the derivation of these two expressions, the occurrence of temperature fluctuations in the considered nanoscale subsystems is either included or neglected. Consequently, our analysis gives also an answer to the widely discussed problem whether temperature fluctuations have to be generally accounted for in thermodynamics or not. To this end, the characteristic length-scales at equal times and temperatures for propylene glycol were determined independently from AC calorimetry in both the above specified ways and from quasielastic neutron scattering (QENS), and compared. The result shows that the cooperative length determined from QENS coincides most consistently with the cooperativity length determined from AC calorimetry measurements for the case that the effect of temperature fluctuations is incorporated in the description. This conclusion indicates that—accounting for temperature fluctuations—the characteristic length can be derived by thermodynamic considerations from the specific parameters of the liquid at glass transition and that temperature does fluctuate in small systems.
Perfect monochromatic acoustic anti-reflection: A first-principles study
Authors: Zhu XingFeng , Wei Qi , Cheng Ying , Wu DaJian , Liu XiaoJun
Published: March 2017

A first-principles method is introduced to design and achieve perfect monochromatic acoustic anti-reflection (AR) at any frequency. We established the relationship between the mass density and bulk modulus of the AR coating, which enabled the removal of any impedance mismatch. Perfect acoustic AR was realized by designing explicit conditions for the impedance matching. Theoretical results were numerically obtained using the finite element method. Importantly, perfect monochromatic acoustic AR was even realized for an ultra-thin AR layer at a deep subwavelength scale. We further approximated a multilayered AR coating with varying bulk moduli, which could provide perfect AR at any frequency. This ultra-thin multilayered AR structure may be beneficial for the minimization and integration of related acoustic devices.
Displacement damage and predicted non-ionizing energy loss in GaAs
Authors: Gao Fei , Chen Nanjun , Hernandez-Rivera Efrain , Huang Danhong , LeVan Paul D.
Published: March 2017

Large-scale molecular dynamics (MD) simulations, along with bond-order interatomic potentials, have been applied to study the defect production for lattice atom recoil energies from 500 eV to 20 keV in gallium arsenide (GaAs). At low energies, the most surviving defects are single interstitials and vacancies, and only 20% of the interstitial population is contained in clusters. However, a direct-impact amorphization in GaAs occurs with a high degree of probability during the cascade lifetime for Ga PKAs (primary knock-on atoms) with energies larger than 2 keV. The results reveal a non-linear defect production that increases with the PKA energy. The damage density within a cascade core is evaluated, and used to develop a model that describes a new energy partition function. Based on the MD results, we have developed a model to determine the non-ionizing energy loss (NIEL) in GaAs, which can be used to predict the displacement damage degradation induced by space radiation on electronic components. The calculated NIEL predictions are compared with the available data, thus validating the NIEL model developed in this study.
Stability of runaway electron beam currents in nitrogen at 100 Torr. Experiments and numerical simulation
Authors: Shklyaev V. A. , Baksht E. Kh. , Belomyttsev S. Ya. , Burachenko A. G. , Grishkov A. A.
Published: March 2017

This paper reports on a series of identical experiments and on a respective particle-in-cell and Monte Carlo simulation to investigate the stability of runaway electron beam currents produced in nitrogen at a highly inhomogeneous electric field. The experiments demonstrate a strong effect of cathode emissivity on the beam current. The numerical simulation shows that the cathode emissivity influences not only the current of the beam but also the mechanisms of its formation.
A high-performance Raman-Ramsey Cs vapor cell atomic clock
Authors: Abdel Hafiz Moustafa , Coget Grégoire , Yun Peter , Guérandel Stéphane , de Clercq Emeric , Boudot Rodolphe
Published: March 2017

We demonstrate a high-performance coherent-population-trapping (CPT) Cs vapor cell atomic clock using the push-pull optical pumping technique in the pulsed regime, allowing the detection of high-contrast and narrow Ramsey-CPT fringes. The impact of several experimental parameters onto the clock resonance and short-term fractional frequency stability, including the laser power, the cell temperature, and the Ramsey sequence parameters, has been investigated. We observe and explain the existence of a slight dependence on laser power of the central Ramsey-CPT fringe line-width in the pulsed regime. We report also that the central fringe line-width is commonly narrower than the expected Ramsey line-width given by 1/(2TR), with TR the free-evolution time, for short values of TR. The clock demonstrates a short-term fractional frequency stability at the level of 2.3×10−13 τ−1/2 up to 100 s averaging time, mainly limited by the laser amplitude modulation noise. Comparable performances are obtained in the conventional continuous wave regime, with the use of an additional laser power stabilization setup. The pulsed interaction allows to reduce significantly the clock frequency sensitivity to laser power variations, especially for high values of TR. This pulsed CPT clock, ranking among the best microwave vapor cell atomic frequency standards, could find applications in telecommunication, instrumentation, defense or satellite-based navigation systems.
3D modeling and characterization of a calorimetric flow rate sensor for sweat rate sensing applications
Authors: Iftekhar Ahmed Tashfin , Ho Jenny Che-Ting , Mellinger Axel , Kaya Tolga
Published: March 2017

Sweat-based physiological monitoring has been intensively explored in the last decade with the hopes of developing real-time hydration monitoring devices. Although the content of sweat (electrolytes, lactate, urea, etc.) provides significant information about the physiology, it is also very important to know the rate of sweat at the time of sweat content measurements because the sweat rate is known to alter the concentrations of sweat compounds. We developed a calorimetric based flow rate sensor using PolydimethylSiloxane that is suitable for sweat rate applications. Our simple approach on using temperature-based flow rate detection can easily be adapted to multiple sweat collection and analysis devices. Moreover, we have developed a 3D finite element analysis model of the device using COMSOL Multiphysics™ and verified the flow rate measurements. The experiment investigated flow rate values from 0.3 μl/min up to 2.1 ml/min, which covers the human sweat rate range (0.5 μl/min–10 μl/min). The 3D model simulations and analytical model calculations covered an even wider range in order to understand the main physical mechanisms of the device. With a verified 3D model, different environmental heat conditions could be further studied to shed light on the physiology of the sweat rate.
Experimental studies on the power–frequency breakdown voltage of CF3I/N2/CO2 gas mixture
Authors: Zhang Xiaoxing , Tian Shuangshuang , Xiao Song , Li Yi , Deng Zaitao , Tang Ju
Published: March 2017

Trifluoroiodomethane is a promising alternative to SF6 because of its good insulation properties and much less serious greenhouse effect than SF6. Previous studies have shown that the insulation performance of CF3I mixed with CO2 or N2 can equal that of SF6. This study explored the frequency breakdown characteristics of CF3I and SF6 mixed with two buffer gases. The effects of air pressure and field strength were analyzed. The fixed mixing ratio of CF3I and SF6 was 30% in the experiment. The breakdown experiment was conducted by changing the mixing ratio of CO2 and N2. Results showed that the CO2/N2 mixture ratio did not exert a synergetic effect, and the CF3I/CO2 breakdown performance was better than that of CF3I/N2 in the quasi-uniform and highly non-uniform electric fields. CO2 possibly provided the C atoms for the entire system to maintain a certain balance in C, and this balance inhibited the decomposition of CF3I. The breakdown performance of SF6/N2 was good in quasi-uniform field, whereas that of SF6/CO2 was good in the highly non-uniform field.