bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal Structure, Infrared Spectrum and Elastic Anomalies in Tuperssuatsiaite
Authors: Colmenero Francisco , Sejkora Jiří , Plášil Jakub
Published: May 2020

The full crystal structure of the phyllosilicate mineral tuperssuatsiaite, including the positions of the hydrogen atoms in its unit cell, is determined for the first time by using first-principles solid-state methods. From the optimized structure, its infrared spectrum and elastic properties are determined. The computed infrared spectrum is in excellent agreement with the experimental spectrum recorded from a natural sample from Ilímaussaq alkaline complex (Greenland, Denmark). The elastic behavior of tuperssuatsiaite is found to be extremely anomalous and significant negative compressibilities are found. Tuperssuatsiaite exhibits the important negative linear compressibility phenomenon under small anisotropic pressures applied in a wide range of orientations of the applied strain and the very infrequent negative area compressibility phenomenon under external isotropic pressures in the range from 1.9 to 2.4 GPa. The anisotropic negative linear compressibility effect in tuperssuatsiaite is related to the increase of the unit cell along the direction perpendicular to the layers charactering its crystal structure. The isotropic negative area compressibility effect, however, is related to the increase of the unit cell dimensions along the directions parallel to the layers.
Quantification of tRNA fragments by electrochemical direct detection in small volume biofluid samples
Authors: McArdle Hazel , Hogg Marion C. , Bauer Sebastian , Rosenow Felix , Prehn Jochen H. M. , Adamson Kellie , Henshall David C. , Spain Elaine
Published: May 2020

Elevated levels of transfer RNA (tRNA) fragments were recently identified in plasma samples from people with epilepsy in advance of a seizure, indicting a potential novel class of circulating biomarker. Current methods for detection and quantitation of tRNA fragments (tRFs) include northern blotting, RNA sequencing or custom Taqman-based PCR assays. The development of a simple, at home or clinic-based test, would benefit from a simple and reliable method to detect the tRFs using small volumes of biofluids. Here we describe an electrochemical direct detection method based on electrocatalytic platinum nanoparticles to detect 3 specific tRFs: 5’AlaTGC, 5'GlyGCC, and 5'GluCTC. Using synthetic tRF mimics we showed this system was linear over 9 orders of magnitude with sub-attomolar limits of detection. Specificity was tested using naturally occurring mismatched tRF mimics. Finally, we quantified tRF levels in patient plasma and showed that our detection system recapitulates results obtained by qPCR. We have designed a tRF detection system with high sensitivity and specificity capable of quantifying tRFs in low volumes of plasma using benchtop apparatus. This is an important step in the development of a point-of-care device for quantifying tRFs in whole blood.
Application of Optical Laser 3D Surface imaging system (Sentinel) in breast cancer radiotherapy
Authors: Liu Mengjiao , Wei Xiaobo , Ding Yun , Cheng Changhai , Yin Wenming , Chen Jie , Wang Kou , Gu Wendong
Published: May 2020

It has been clearly confirmed that radiation therapy (RT) after breast conserving surgery (BCS) is an effective treatment modality comparable to mastectomy for early breast cancer. The purpose of this study was to further evaluate the accuracy of 3D surface imaging system (Sentinel) for breast cancer patients received BCS. The optical surface scans and CBCT scans were acquired before and immediately after couch movement correction. The deviation of the CBCT scans from the reference planning CT was considered an estimate for the residual errors for patient setup correction. The planning target volume (PTV) margins for treatment sessions was calculated according to the setup errors. We obtained a total of 245 sets of data collected from 49 breast cancer patients. Compared with Sentinel setup errors, the residual setup errors as determined by the CBCT scans after couch movement correction were reduced in the six directions. The PTV margins derived from the CBCT residual errors were all less than 5 mm in X, Y, and Z directions. Our results suggested that Optical surface imaging can be applied in positioning for breast cancer patient accurately without unnecessary imaging dose.
A novel functional cross-interaction between opioid and pheromone signaling may be involved in stress avoidance in Caenorhabditis elegans
Authors: Park Jun Young , Cheong Mi Cheong , Cho Jin-Young , Koo Hyeon-Sook , Paik Young-Ki
Published: May 2020

Upon sensing starvation stress,Caenorhabditis eleganslarvae (L2d) elicit two seemingly opposing behaviors to escape from the stressful condition: food-seeking roaming mediated by the opioid peptide NLP-24 and dauer formation mediated by pheromones. Because opioid and pheromone signals both originate in ASI chemosensory neurons, we hypothesized that they might act sequentially or competitively to avoid starvation stress. Our data shows that NPR-17 opioid receptor signaling suppressed pheromone biosynthesis and the overexpression of opioid genes disturbed dauer formation. Likewise, DAF-37 pheromone receptor signaling negatively modulatednlp-24expression in the ASI neurons. Under short-term starvation (STS, 3 h), both pheromone and opioid signaling were downregulated ingpa-3mutants. Surprisingly, thegpa-3;nlp-24double mutants exhibited much higher dauer formation than seen in either of the single mutants. Under long-term starvation (LTS, >24 h), the stress-activated SKN-1a downregulated opioid signaling and then enhanced dauer formation. Both insulin and serotonin stimulated opioid signaling, whereas NHR-69 suppressed opioid signaling. Thus, GPA-3 and SKN-1a are proposed to regulate cross-antagonistic interaction between opioids and pheromones in a cell-specific manner. These regulatory functions are suggested to be exerted via the selective interaction of GPA-3 with NPR-17 and site-specific SKN-1 binding to the promoter ofnlp-24to facilitate stress avoidance.
Identification of potential microRNA panels for pancreatic cancer diagnosis using microarray datasets and bioinformatics methods
Authors: Shams Roshanak , Saberi Samaneh , Zali Mohammadreza , Sadeghi Amir , Ghafouri-Fard Soudeh , Aghdaei Hamid Asadzadeh
Published: May 2020

Pancreatic cancer (PC) is a malignancy with little/no warning signs before the disease reaches its ultimate stages. Currently early detection of PC is very difficult because most patients have non-specific symptoms leading to postponing the correct diagnosis. In this study, using multiple bioinformatics tools, we integrated various serum expression profiles of miRNAs to find the most significant miRNA signatures helpful in diagnosis of PC and constructed novel miRNA diagnosis models for PC. Altogether, 27 differentially expressed miRNAs (DEMs) showed area under curve (AUC) score >80%. The most promising miRNAs, miR-1469 and miR-4530, were individually able to distinguish two groups with the highest specificity and sensitivity. By using multivariate cox regression analyses, 5 diagnostic models consisting of different combinations of miRNAs, based on their significant expression algorithms and functional properties were introduced. The correlation model consisting of miR-125a-3p, miR-5100 and miR-642b-3p was the most promising model in the diagnosis of PC patients from healthy controls with an AUC of 0.95, Sensitivity 0.98 and Specificity 0.97. Validation analysis was conducted for considered miRNAs on a final cohort consist of the microarray data from two other datasets (GSE112264 & GSE124158) . These results provide some potential biomarkers for PC diagnosis after testing in large case-control and cohort studies.
Saliva proteomic patterns in patients with molar incisor hypomineralization
Authors: Bekes K. , Mitulović G. , Meißner N. , Resch U. , Gruber R.
Published: May 2020

Molar incisor hypomineralization (MIH) is an endemic pediatric disease with an unclear pathogenesis. Considering that saliva controls enamel remineralization and that MIH is associated with higher saliva flow rate, we hypothesized that the protein composition of saliva is linked to disease. To test this, we enrolled 5 children aged 6–14 years with MIH showing at least one hypersensitive molar and 5 caries-free children without hypomineralization. Saliva samples were subjected to proteomic analysis followed by protein classification in to biological pathways. Among 618 salivary proteins identified with high confidence, 88 proteins were identified exclusively in MIH patients and 16 proteins in healthy controls only. Biological pathway analysis classified these 88 patient-only proteins to neutrophil-mediated adaptive immunity, the activation of the classical pathway of complement activation, extracellular matrix degradation, heme scavenging as well as glutathione -and drug metabolism. The 16 controls-only proteins were associated with adaptive immunity related to platelet degranulation and the lysosome. This report suggests that the proteaneous composition of saliva is affected in MIH patients, reflecting a catabolic environment which is linked to inflammation.
Allelic variants between mouse substrains BALB/cJ and BALB/cByJ influence mononuclear cardiomyocyte composition and cardiomyocyte nuclear ploidy
Authors: Gan Peiheng , Patterson Michaela , Watanabe Hirofumi , Wang Kristy , Edmonds Reilly A. , Reinholdt Laura G. , Sucov Henry M.
Published: May 2020

Most mouse cardiomyocytes (CMs) become multinucleated shortly after birth via endoreplication and interrupted mitosis, which persists through adulthood. The very closely related inbred mouse strains BALB/cJ and BALB/cByJ differ substantially (6.6% vs. 14.3%) in adult mononuclear CM level. This difference is the likely outcome of a single X-linked polymorphic gene that functions in a CM-nonautonomous manner, and for which the BALB/cByJ allele is recessive to that of BALB/cJ. From whole exome sequence we identified two new X-linked protein coding variants that arose de novo in BALB/cByJ, in the genes Gdi1 (R276C) and Irs4 (L683F), but show that neither affects mononuclear CM level individually. No BALB/cJ-specific X-linked protein coding variants were found, implicating instead a variant that influences gene expression rather than encoded protein function. A substantially higher percentage of mononuclear CMs in BALB/cByJ are tetraploid (66.7% vs. 37.6% in BALB/cJ), such that the overall level of mononuclear diploid CMs between the two strains is similar. The difference in nuclear ploidy is the likely result of an autosomal polymorphism, for which the BALB/cByJ allele is recessive to that of BALB/cJ. The X-linked and autosomal genes independently influence mitosis such that their phenotypic consequences can be combined or segregated by appropriate breeding, implying distinct functions in karyokinesis and cytokinesis.
Loss of SRSF2 triggers hepatic progenitor cell activation and tumor development in mice
Authors: Zhang Chang , Shen Lei , Yuan Wei , Liu Yuguo , Guo Ruochen , Luo Yangjun , Zhan Zheng , Xie Zhiqin , Wu Guohao , Wu Wenwu , Feng Ying
Published: May 2020

Splicing factor SRSF2 is frequently mutated or up-regulated in human cancers. Here, we observe that hepatocyte-specific deletion of Srsf2 trigger development of hepatocellular carcinoma (HCC) in mice, which also involves inflammation and fibrosis. Importantly, we find that, when compensatory hepatocyte proliferation is impaired, activation of hepatic progenitor cells (HPCs) play an important role in liver regeneration and tumor formation. Moreover, the cells of HCC- bearing livers display both HPC and hepatocyte markers, with gene expression profiling suggesting HPC origin and embryonic origin. Mechanically, we demonstrate that levels of oncofetal genes insulin-like growth factor 2 (Igf2) and H19 are significantly increased in the tumors, likely due to decreased DNA methylation of the Igf2/H19 locus. Consequently, signaling via the Igf2 pathway is highly activated in the tumors. Thus, our data demonstrate that loss of Srsf2 triggers HPC-mediated regeneration and activation of oncofetal genes, which altogether promote HCC development and progression in mice.
Chemometrics as a Green Analytical Tool
Authors: Wongravee Kanet , Ishigaki Mika , Ozaki Yukihiro
Published: May 2020

Chemometrics is a very important technique for green analytical chemistry. In this chapter, after describing briefly the history of chemometrics in green chemistry and its application to green analytical chemistry, the complexity of datasets, the design of experiments (DOE) and pre-processing methods, which provide basic knowledge for chemometrics, are outlined. Various methodologies of chemometrics are then introduced, which are classified into unsupervised pattern recognition, such as hierarchical cluster analysis (HCA) and principal component analysis (PCA), and supervised pattern recognition, such as multiple linear regression (MLR), principal component regression (PCR) and partial least-squares regression (PLSR). Finally, some examples of applications of spectroscopy–chemometrics research are described, such as the application of moving window partial least-squares regression (MWPLSR) to in vivo non-invasive monitoring of blood glucose by near-infrared diffuse reflectance spectroscopy and a Raman imaging study of the aggregation of lycopene in vivo in tomato.
Development and application of a ratiometric nanosensor for measuring pH inside the gastrointestinal tract of zooplankton
Authors: Davis Adam , Nasser Fatima , Lead Jamie R. , Shi Zongbo
Published: May 2020

The pH in the anterior gut of Daphnia magna is more than 2 pH units lower than the cultural medium.
Transformation of ZIF-8 nanoparticles into 3D nitrogen-doped hierarchically porous carbon for Li–S batteries
Authors: Cao Guiqiang , Bi Da , Zhao Jingxiang , Zheng Jing , Wang Zhikang , Lai Qingxue , Liang Yanyu
Published: May 2020

A novel transformation strategy assisted with ammonia treatment was successfully developed to fabricate ZIF-8-derived nitrogen-doped hierarchically porous carbon (NHPC/NH3).
First-principles calculations of electronic structure and optical and elastic properties of the novel ABX3-type LaWN3perovskite structure
Authors: Liu Xing , Fu Jia , Chen Guangming
Published: May 2020

Using first-principles calculation, the stableR3cLaWN3as a new ABX3-type advanced perovskite structure is designed in the plan of the material genome initiative (MGI), which helps to widen the nowadays nitride perovskite material's application.
Applications of atomic layer deposition and chemical vapor deposition for perovskite solar cells
Authors: Raiford James A. , Oyakhire Solomon T. , Bent Stacey F.
Published: May 2020

A review on the versatility of atomic layer deposition and chemical vapor deposition for the fabrication of stable and efficient perovskite solar cells.
Effect of substituents in sulfoxides on the enhancement of thermoelectric properties of PEDOT:PSS: experimental and modelling evidence
Authors: Zhu Qiang , Yildirim Erol , Wang Xizu , Kyaw Aung Ko Ko , Tang Tao , Soo Xiang Yun Debbie , Wong Zicong Marvin , Wu Gang , Yang Shuo-Wang , Xu Jianwei
Published: May 2020

PEDOT:PSS doped with a series of functionalized sulfoxides exhibits enhanced electrical conductivity and Seebeck coefficient.
Bioinspired selective synthesis of liquid-crystalline nanocomposites: formation of calcium carbonate-based composite nanodisks and nanorods
Authors: Nakayama Masanari , Kajiyama Satoshi , Kumamoto Akihito , Ikuhara Yuichi , Kato Takashi
Published: May 2020

Colloidal nanodisk liquid-crystalline composites consisting of an acidic polymer and CaCO3 are developed. Selective synthesis of nanodisk and nanorod is achieved by biomineralization-inspired approaches.
Chemical affinity and dispersibility of boron nitride nanotubes
Authors: Torres Castillo C. S. , Bruel C. , Tavares J. R.
Published: May 2020

The chemical affinity of purified boron nitride nanotubes (BNNTs) is measured in terms of Hansen solubility parameters, taking into account relative sedimentation time in various solvents. This improves predictions for the dispersion of BNNTs.
Effect of graphene quantum dot size on plant growth
Authors: Xu Yao , Lu Yihua , Li Jiagen , Liu Rulin , Zhu Xi
Published: May 2020

By controlling the sizes of GQDs through the use of an intelligent robot, we found a GQD size that best promoted the growth of plants.
Light and latex: advances in the photochemistry of polymer colloids
Authors: Scott Philip J. , Kasprzak Christopher R. , Feller Keyton D. , Meenakshisundaram Viswanath , Williams Christopher B. , Long Timothy E.
Published: May 2020

Unparalleled temporal and spatial control of colloidal chemical processes introduces immense potential for the manufacturing, modification, and manipulation of latex particles.
Polymerization-induced self-assembly for the fabrication of polymeric nano-objects with enhanced structural stability by cross-linking
Authors: Zhang Wen-Jian , Kadirkhanov Jamshid , Wang Chang-Hui , Ding Sheng-Gang , Hong Chun-Yan , Wang Fei , You Ye-Zi
Published: May 2020

This review discusses the strategies of core-cross-linking in most of the PISA literatures (including post-polymerization cross-linking, photo-cross-linking and in situ cross-linking) and the applications of the cross-linked nano-objects.
Effects of ozone treatment on SOD activity and genes in postharvest cantaloupe
Authors: Zhang Huijie , Zhang Xiaojun , Dong Chenghu , Zhang Na , Ban Zhaojun , Li Li , Yu Jinze , Hu Yunfeng , Chen Cunkun
Published: May 2020

Ozone has been shown to play a positive role in the storage and preservation of agricultural products.
Polypyrrole modified magnetic reduced graphene oxide composites: synthesis, characterization and application for selective lead adsorption
Authors: Liu Zhanmeng , Gao Zhimin , Xu Lichun , Hu Fengping
Published: May 2020

Compared to Fe3O4/rGO, the PPy-FG composites showed desirable adsorption capacity and selectivity for Pb(ii) from water.
Deposition of an ultra-thin polyaniline coating on a TiO2 surface by vapor phase polymerization for electrochemical glucose sensing and photocatalytic degradation
Authors: Majumdar Sibani , Mahanta Debajyoti
Published: May 2020

Here, we have synthesized an ultra-thin coating of polyaniline on a TiO2 nanoparticle surface (PANI–TiO2) using a simple vapor phase polymerization method.
Cs2NaGaBr6: a new lead-free and direct band gap halide double perovskite
Authors: Saeed Yasir , Amin Bin , Khalil Haleema , Rehman Fida , Ali Hazrat , Khan M. Imtiaz , Mahmood Asif , Shafiq M.
Published: May 2020

In this work, we have studied new double perovskite materials, A21+B2+B3+X61−, where A21+ = Cs, B2+ = Li, Na, B3+ = Al, Ga, In, and X61−.
Post-synthetic modification of imine linkages of a covalent organic framework for its catalysis application
Authors: Yan Qianqian , Xu Huanjun , Jing Xuechao , Hu Hui , Wang Shenglin , Zeng Chaoyuan , Gao Yanan
Published: May 2020

A new approach for post-synthetic modification of covalent organic frameworks has been developed based on the modification of the linkages and the resulting COF exhibited excellent catalytic performance towards cycloaddition of epoxides and CO2.
Enhanced thermal stability, hydrophobicity, UV radiation resistance, and antibacterial properties of wool fabric treated with p-aminobenzenesulphonic acid
Authors: Hassan Mohammad Mahbubul
Published: May 2020

The treatment with para-aminobenzenesulphonic acid produced a multifunctional wool fabric with enhanced hydrophobicity, thermal stability, UV resistance, and antibacterial properties.
Wrist flexible heart pulse sensor integrated with a soft pump and a pneumatic balloon membrane
Authors: Yamaguchi Takafumi , Yamamoto Daisuke , Arie Takayuki , Akita Seiji , Takei Kuniharu
Published: May 2020

Wearable and flexible heart pulse sensor is proposed to monitor the detailed pulse signal from a wrist stably and reliably by integrating a tactile pressure sensor and a soft pneumatic balloon operated by a soft pump.
Detection of L-band electron paramagnetic resonance in the DPPH molecule using impedance measurements
Authors: Chaudhuri Ushnish , Mahendiran R.
Published: May 2020

(a) Schematic diagram of our experimental set up. (b) Resistance and reactance of the DPPH molecule for 2 GHz current in the strip coil.
Borohydride catalyzed redistribution reaction of hydrosilane and chlorosilane: a potential system for facile preparation of hydrochlorosilanes
Authors: Chen Yi , Ai Liqing , Li Yongming , Xu Caihong
Published: May 2020

A borohydride catalyzed Si–H/Si–Cl redistribution system was established to prepare hydrochlorosilanes facilely and efficiently.
Rapidly self-deoxygenating controlled radical polymerization in water via in situ disproportionation of Cu(i)
Authors: Liarou Evelina , Han Yisong , Sanchez Ana M. , Walker Marc , Haddleton David M.
Published: May 2020

The rapidly self-deoxygenating Cu-RDRP in aqueous media is investigated.
Boosting cell performance with self-supported PtCu nanotube arrays serving as the cathode in a proton exchange membrane fuel cell
Authors: Yao Dewei , Yu Hongmei , Song Wei , Gao Xueqiang , Fan Zhixuan , Jiang Guang , Sun Xinye , Shao Zhigang
Published: May 2020

The high cost and huge consumption of the Pt catalyst hinder the large-scale commercialization of fuel cells.
One‐pot green and simple synthesis of polyvinyl pyrrolidone capped for copper nanoclusters for high selectivity sensing of fluazinam
Authors: Cai Zhifeng , Pang Shulin , Ma Xinru , Zhu Li , Zhang Yefan , Tian Fang , Zhang Caifeng
Published: May 2020

In this contribution, polyvinyl pyrrolidone capped copper nanoclusters (PVP‐Cu NCs) were synthesised through a one‐pot route possessing the advantages of rapidness and environmental friendliness. Also, the optical characteristics of the as‐prepared Cu NCs were characterised using fluorescence spectroscopy, UV–vis absorption spectroscopy. The structure and composition were studied through Fourier transform infrared, transmission electron microscopy, X‐ray photoelectron spectroscopy. It exhibited good water solubility, excellent photo stability, and resistance to sodium chloride. The Cu NCs revealed blue fluorescence and displayed excitation‐dependent fluorescence characteristics. More importantly, the fluorescence intensity of PVP‐Cu NCs was linearly quenched in the range of 5–80 μM (concentrations of fluazinam) and the detection limit was 0.98 μM. Finally, the fluorescence sensor was successfully employed to detect fluazinam in natural water samples.
Nanoscale zero‐valent iron/zinc oxide flower‐like heterostructure composites: synthesis and removal of selenium in aqueous solution
Authors: Bu Xiaohai , Yang Jintao , Zhang Xian , Li Dongxian , Feng Mingxin , Fu Qiang
Published: May 2020

In this work, novel flower‐like nanoscale zero‐valent iron/zinc oxide heterostructure composites were prepared, characterised and used for the enhanced removal of Se(IV) from water. The morphological identification showed that nZVI nanoparticles were uniformly loaded on ZnO nanosheets to minimise their aggregation. Batch experimental results demonstrated that the composites exhibited higher removal efficiency and rate constant on Se(IV) immobilisation than pristine flower‐like ZnO and nZVI because of the enhanced dispersion of nZVI nanoparticles. Solution pH, initial Se(IV) concentration as well as interfering ions that affect the removal capacity of Se(IV) were further studied. These results suggested that the composites could be a promising candidate for the potential application in effective remediation of Se‐contaminated wastewater.
Microwave‐assisted synthesis of pectin‐stabilised CdS/ZnS core/shell nanocrystals and enhanced photocatalytic performance
Authors: Qin Dezhi , Yang Guangrui , Wang Yabo , Zhang Jiajia , Zhang Li
Published: May 2020

Pectin‐conjugated CdS/ZnS core/shell nanocrystals were prepared by using a microwave‐assisted approach without the addition of any external ligands. The prepared cubic phase CdS/ZnS nanocrystals were uniform and mono‐dispersed with sizes of 6–9 nm. The charge and long‐chain structure of pectin molecules effectively prevented the aggregation of CdS/ZnS nanocrystals. In addition, pectin molecules have multiple functional groups, such as O–H, C=O, and COO−, which could conjugate with the surface of samples to control the growth of CdS/ZnS nanocrystals. Thermogravimetric analysis provided evidence that the obtained products are inorganic–organic hybrid materials. Based on the analysis of ultraviolet–visible spectra, it was found that the formation of ZnS shell led to a red‐shift and an enhancement of absorption of CdS/ZnS nanocrystals compared with that of CdS. Photocatalytic activity of CdS/ZnS nanocrystals was monitored by the degradation of Rhodamine B under visible light irradiation. The presence of ZnS shell inhibited photo‐corrosion and photo‐dissolution of CdS nanocatalyst, thus resulting in a significant enhancement of photocatalytic activity and stability.
Highly efficient Michael additions of acrylonitrile with alcohols over K2CO3/zeolite catalysts in a solvent‐free system
Authors: Zhan Hongju , Zhao Lin , Xia Qinghua , Zhou Dan , Ma Xuetao , Lu Xinhuan
Published: May 2020

The supported base/zeolite catalysts are prepared and applied in the catalytic Michael additions of acrylonitrile with monohydric alcohols to 3‐alkoxypropanenitriles in a solvent‐free system. The catalysts are characterised by powder X‐ray diffraction. For the Michael addition of methanol to acrylonitrile, 10% K2CO3/ZSM‐5 shows the best activity with 98.3 mol% conversion of acrylonitrile and 100% selectivity of 3‐methoxypropanenitrile. The recyclable stability of the 10% K2CO3/ZSM‐5 catalyst is confirmed. The effects of various parameters are investigated systematically. By comparing the catalytic activity of anion‐exchanged CO32−‐resin for the titled addition, a feasible reaction route is proposed.
Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm
Authors: Kravchenko E. , Giroletti M. , Hada K. , Meier D. L. , Nakamura M. , Park J. , Walker R. C.
Published: May 2020

We report on high angular resolution polarimetric observations of the nearby radio galaxy M87 using the Very Long Baseline Array at 24 GHz (λ = 1.3 cm) and 43 GHz (λ = 7 mm) in 2017–2018. New images of the linear polarization substructure in the nuclear region are presented, characterized by a two-component pattern of polarized intensity and smooth rotation of the polarization plane around the 43 GHz core. From a comparison with an analogous dataset from 2007, we find that this global polarization pattern remains stable on a time interval of 11 yr, while showing smaller month-scale variability. We discuss the possible Faraday rotation toward the M87 nucleus at centimeter to millimeter wavelengths. These results can be interpreted in a scenario where the observed polarimetric pattern is associated with the magnetic structure in the confining magnetohydrodynamic wind, which also serves as the source of the observed Faraday rotation.
High angular resolution study of the super star cluster population in IRAS 17138−1017
Authors: Lam N. T. , Gratadour D. , Rouan D. , Grosset L.
Published: May 2020

Aims. Currently, the global characteristics and evolution of super star clusters (SSCs) are not well understood, due to the large distances to their host galaxies. We aim to study the population of SSCs in IRAS 17138-1017, a luminous infrared galaxy (LIRG), in terms of age, extinction, mass, and luminosity distribution.

Methods. We analyzed imaging data in the near-infrared from the GeMS/GSAOI instrument on the Gemini telescope and generated simulations with the radiative transfer code MontAGN. The extraction of SSCs from the images and their photometry in J, H, and Ks allowed us to derive color-color and color-magnitude diagrams. Comparison with a theoretical stellar evolutionary track gives a first hint into the extinction towards each SSC, as well as their ages, despite some degeneracy between those two quantities. Spectra given by our radiative transfer code MontAGN, which includes dust emission, also provide insightful predictions and comparisons.

Results. We detect with a fair degree of confidence 54 SSCs of mKs between 16 mag and 21 mag with a median instrumental uncertainty of 0.05 mag. When plotted on a color–color diagram and a color–magnitude diagram, it appears that most of the sources are very much extinct with respect to an intrinsic theoretical evolutionary track. Once de-reddened, the colors point unambiguously to two distinct and very recent starburst episodes at 2.8 and 4.5 Myr. While the SSCs in the 4.5 Myr starburst are distributed along the spiral arms, the 2.8 Myr SSCs are concentrated in the central region. The luminosity and mass functions present a classical power-law behavior, although with shallower slopes than generally observed in LIRGs. Comparison with radiative transfer simulations shows that, the dust thermal emission and scattered light are negligible and could not explain the few very red SSCs that could not be de-reddened safely.
Satellite image analysis reveals changes in seagrass beds at Van Phong Bay, Vietnam during the last 30 years
Authors: Vo Trong-Thach , Lau Khin , Liao Lawrence M. , Nguyen Xuan-Vy
Published: May 2020

Seagrass meadows are fragile ecosystems in the coastal zone. Natural disasters, land reclamation and various human activities seem to exert negative impacts on the distribution and biological performance of seagrass beds in Vietnam. In this present study, satellite Landsat TM/OLI image analysis was applied to determine changes in seagrass distribution at Van Phong Bay, Vietnam in the last 30 years. The maximum likelihood decision rule was used to extract seagrass bed distribution data. The error matrix using the in situ reference data for HLM image classification was 81–95% accurate, and Kappa coefficients were between 0.72 and 0.91. The results indicated that 186.2 ha (or 35.8%) of the original seagrass beds were lost in the last three decades at Van Phong Bay, and decline in each specific site may have been due to different causes. Typhoons may have caused the loss of seagrass beds at open-sea sites whereas aquaculture activities, excavation and terrigenous obliteration may have caused such losses in protected sites.
Experimental studies of benthos resistance to mechanical burying under the dredging material
Authors: Chusov Alexander , Shilin Mikhail , Gogoberidze George , Lednova Julia , Bobylev Nikolai
Published: May 2020

The goal of the fulfilled research is the study of the influence of the sedimentary suspension from the dredging material on the benthic hydrobionts. In laboratory aquariums six series of experiments were carried out with triple replication on the ability of different benthic organisms to dig out the soil strata due to their periodic burying by marine sand. These experiments were oriented on biota of Eastern Gulf of Finland and the Neva Bay, where a number of deposit sites for dredging material are located presently. Representatives of three main groups of hydrobionts of these areas were selected for experiments – Chironomidae, Gastropoda and Oligochaeta. The ability of different hydrobiont species to overcome the stress effect of the burying under the dredged material was estimated quantitatively. The results show, that the resistance of the studied species to mechanical burying is decreasing in accordance to the scheme: Chironomus plumosus > Melanoides tuberculata > Tubifex tubifex, and depends from the thickness of the layer of dredged material.
Life cycle cost and energy conservation for water system pumping station reconstruction
Authors: Maksimova Svetlana , Shkileva Anna , Verevkina Ekaterina
Published: May 2020

The main goal of this study is evaluation of reconstruction options for water pumping stations, regarding various factors (equipment purchase cost, maintenance, energy consumption). The search for the most profitable solution was carried out using the life cycle cost methodology for the urban water supply system’s first lift pump station. An analysis of the operating modes of the pumping station was carried out using curves of pumps and system. It was found that the option with a higher purchase price has the best technological indicators, including energy consumption. The expediency of the complete replacement of pumping equipment is confirmed by an analysis of life cycle costs.
Optimal parameters for drilling explosions when developing coal deposits by open-pit method
Authors: Afanasev Pavel , Pasynkov Andrey , Kurta Ivan
Published: May 2020

The article discusses two deposits of coal mining by the open method. The «Zarechnyi» open-pit is located in Kuzbass, and the «Vostochno-Beiskyi» open-pit is in Khakassia. The main parameters of drilling and blasting operations are given, the geological structure of the deposits is described. The methods of calculating the specific charge, the diameter of the wells and the grid of wells are considered. Blasting operations are an integral part of the mining process. The cost of finished products and the quality of raw materials supplied to the crushing and screening complexes depend on the results of blasting of the rock mass. The currently used retractable blasting technologies, produced according to standard designs, lead to large energy losses during the explosion, as well as to the output of the oversized fraction, which in turn leads to downtime, reduced productivity and breakdown of transport and loading equipment. The paper substantiates the parameters of drilling and blasting operations taking into account the physical processes occurring in the explosive cavity and during the stress wave propagation in the rock mass. Parameters of detonation products are estimated on the basis of shock-wave compression, the refraction of a detonation wave into a rock based on the theory of the breakdown of an arbitrary discontinuity, the stress wave propagation taking into account polymorphic transformations and dissipation energy. Recommendations for reducing the specific charge of explosives, for choosing the diameter of the borehole charge and the grid of wells are proposed.
Influence of air temperature and snow cover accumulation regimes on ground freezing depth variations in Moscow region
Authors: Frolov Denis
Published: May 2020

According to developed algorithm and calculating scheme the calculations of ground freezing depth variations for observation sites of meteorological stations of Moscow region (Mozhaysk, Kolomna) were performed on basis of meteorological data on air temperature and snow cover thickness for winter periods of 1988/89-2018/19. The comparison of calculated and available in open access observation data on ground freezing depth for these winter periods was also conducted and indicated good correspondence. The calculating scheme for ground freezing is constructed on basis of three layer media heat conductivity problem (snow cover, frozen and thawed ground) with phase transition on the boundary of frozen and unfrozen ground. Heat balance equation includes phase transition energy, inflow of heat from unfrozen ground and outflow to frozen ground, snow cover and atmosphere. The heat flux is calculated on basis of Fourier law as a product of heat conductivity and temperature gradient. It is supposed, that temperature changes in each media linearly.
Integrated efficiency evaluation of the heat- supplying enterprises activity
Authors: Еvseev Evgeny , Kisel Tatiana
Published: May 2020

Heat supply is the industry which forms the comfortable living environment in many respects. It is especially felt in those regions, where climatic conditions demand maintenance of the comfortable thermal mode during the cold winter period. On the one hand, the efficiency of the heat- supplying enterprises activity determines the level of the population comfort, including temperature condition in rooms, uninterrupted heat supply, on the other hand, it influences the tariff level for heat supply services. The article presents the results of the research, which purpose was to reveal the indicators of the heat-supplying enterprises activity, allowing to estimate their efficiency in the most complete way from the position of various stakeholders. The system of indicators, created as a result of the conducted research, can be used by both management of the enterprise, and external stakeholders for the efficiency evaluation of the heat-supplying enterprise in statics and in dynamics.
Vibration safety to reduce the risk of cardiovascular disease in workers
Authors: Il’ev Alexei , Chertov Yuri , Litvinov Artyom , Kobzeva Nataliya
Published: May 2020

Some manufacturing processes are accompanied by significant noise and vibration. Sources of intense noise and vibration are machines and mechanisms with unbalanced rotating masses, as well as technological installations and apparatuses in which the movement of gases and liquids occurs at high speeds and has a pulsating character. The modern development of technology, equipping enterprises with powerful and fast- moving machines and mechanisms leads to the fact that people are constantly exposed to noise of increasing intensity. Increasing noise and vibration in the workplace has a harmful effect on the human body. As a result of prolonged exposure to noise, the normal activity of the cardiovascular and nervous systems, digestive and hematopoietic organs is disturbed, and professional hearing loss develops, the progression of which can lead to complete hearing loss. Among industrial hazards, noise and vibration occupy one of the leading places among production hazards. The harmful effects of increased noise levels on the human body are well khown, therefore, the relevance of this problem is obvious.
The effect of noise on the human body, in particular, on cardiovascular diseases
Authors: Staseva Elena , Kvitkina Marina , Litvinov Artyom , Kobzeva Nataliya
Published: May 2020

Some manufacturing processes are accompanied by significant noise and vibration. Sources of intense noise and vibration are machines and mechanisms with unbalanced rotating masses, as well as technological installations and apparatuses in which the movement of gases and liquids occurs at high speeds and has a pulsating character. The modern development of technology, equipping enterprises with powerful and fast-moving machines and mechanisms leads to the fact that people are constantly exposed to noise of increasing intensity. Increasing noise and vibration in the workplace has a harmful effect on the human body. As a result of prolonged exposure to noise, the normal activity of the cardiovascular and nervous systems, digestive and hematopoietic organs is disturbed, and professional hearing loss develops, the progression of which can lead to complete hearing loss. Among industrial hazards, noise and vibration occupy one of the leading places among production hazards. The harmful effects of increased noise levels on the human body are well khown, therefore, the relevance of this problem is obvious.
Features of compressed rods calculations with account of initial imperfections and creep effects
Authors: Chepurnenko Viacheslav , Yazyev Batyr , Dubovitskaya Ludmila
Published: May 2020

The article presents solutions to the problem of rod buckling, taking into account creep effects. Trigonometric series, the finite difference method in combination with the programming language MATLAB, as well as the finite element method in the ANSYS software package were used in the solutions. The behavior of the rods is researched for two types of relations between strain and stress during creep, with strains in an explicit and implicit form. When solving, the criterion of initial imperfections with their different values is used, as well as the tangential-modular theory. The results obtained for the two creep models are compared. The conclusion is made about the accuracy of the results of calculations in ANSYS with the presence of a combination of geometric and physical nonlinearity for various creep models.
Flat area characteristics of polygons circumscribing parabolic figures
Authors: Egereva Elvira , Surovtsev Dmitry , Nepovinnyy Zakhar
Published: May 2020

The works elucidates the extremum areas of the polygons circumscribing parabolic figures. It is shown that the ratio of the areas of the polygons circumscribed near parabolic figures to the areas of the corresponding figures always remains a constant value, independent of the coefficients characterizing the quadratic function. The only point at which the function under study reaches its minimum value is found. The question of the necessary conditions for the existence of a circle circumscribed about a parabolic quadrilateral found in the Ptolemy theorem is being considered.
Spatial forced oscillations of axisymmetric inhomogeneous systems
Authors: Mirsaidov Mirziyod , Nosirov Abdurasul , Nasirov Ismoil
Published: May 2020

The aim of this paper is to develop an adequate mathematical model, methods and algorithms for solving three-dimensional problems for axisymmetric spatial inhomogeneous viscoelastic systems (shells, foundations and bases) and to assess the dynamics of protective shell (containment) of a nuclear power plant (NPP) under resonant modes of vibration. The problem is solved using the semi-analytical finite element method. Firstly, the eigenmodes of vibration of the system are determined in an elastic three-dimensional statement, secondly, the solution to the problem of forced vibrations of viscoelastic systems is constructed using the expansion of these eigenmodes of vibration. Viscoelastic properties of the material are described using the hereditary Boltzmann-Volterra theory. The principle of virtual displacements is used to simulate dynamic processes in inhomogeneous viscoelastic systems. The convergence and accuracy of the solutions obtained are investigated by test problems. The frequency response characteristics (FRC) in various points of the NPP containment are estimated at various viscosity parameters of the material. It was revealed that the highest amplitude of vibrations in resonance modes occurs at close values of the frequency of external effect to the first eigen frequencies of the system; in the presence of dense spectra of eigen frequencies of the system, the highest amplitudes can occur at higher frequencies of external effect.
Method of power consumption calculation of air conditioning systems on the basis of probability-statistic climate model
Authors: Malikova Olga
Published: May 2020

The article discusses the methodology for calculating the annual, seasonal and monthly consumption of heat, cold, electricity and water for air conditioning systems based on the temperatures and enthalpies of outdoor air averaged for each weather zone during the working day according to a probabilistic-statistical climate model. The article contains a brief description of the engineering methodology for quick manual calculation of resource consumption with a comparison of the results when using simplified tables of climatic information about weather zones of various external air purification in devices of the central air conditioning system. An example of calculating the annual costs for a system controlled by the "optimal modes" method according to the direct flow scheme with a bypass of the humidification chamber and the controlled process in the air cooler is studied. The advantages of the proposed engineering method lie not only in accuracy, but also in that it allows you to consider the operation of the installation during the year with greater detail for each air purifier. It is shown that the simplified procedure is suitable for use, since it gives discrepancies with machine calculation, which is no more than 10%, which is acceptable for engineering practice.
Flat bending shape stability of the beams with variable section width
Authors: Lapina Anastasia , Yazyev Serdar , Chepurnenko Anton , Dubovitskaya Irina
Published: May 2020

The paper proposes a methodology for calculating lateral buckling of beams of variable rectangular cross section based on the energy approach. The technique is considered on the example of a cantilever beam of variable width with two sections under the action of a concentrated force. The twist angle function was set in the form of a trigonometric series. As a result, the problem is reduced to a generalized secular equation.
Defects in the hydro-insulation of the underground part of the building of Tovstonogov Bolshoi Drama Theater after the reconstruction
Authors: Yudina Antonina
Published: May 2020

The paper presents the study of defects in the hydro-insulation of the underground part of the BDT building (“The Russian State Bolshoi Drama Theater named after Tovstonogov G.A.”) after the reconstruction. Within the reconstruction of such buildings, work is often performed to deepen the floor below the existing level of the foundation to create the additional area. During excavation works for deepening, demolition of the old concrete floors and after arrangement of a new floor slab in the basement, as a result of poorly executed hydro-insulation works, capillary moisture is raised along the body of the wall. As a result, wall structures are in conditions of high humidity, which leads to their gradual destruction.
Dismantling of hipped roof and restoration of cribbed structure of monastic buildings, churches and temples
Authors: Zhivotov Dmitry , Galaktionova Olga
Published: May 2020

The paper is devoted to the problem of adaptation and restoration of monastic structures, churches and temples without complete dismantling of the elements of the main load-bearing structures, using technologies and methods of work that allow delicately and effectively restoring the most important elements of buildings. The progress of work on the restoration of the hipped roof, using the lifting method - lifting the load-bearing part of the cribbed roof structure, is accurately and consistently described in the paper, as well as flexibility and efficiency in choosing a new solution for lifting, taking into account the features of the object identified during the work. The work on raising the roof was carried out during the course of adapting the building to modern use, based on the needs of the Kirillo-Belozersky museum-reserve.
Application of non-metric digital cameras to control the volume of soil displaced when performing earthworks
Authors: Rogova Nina
Published: May 2020

Moving soil during earthworks at a construction site requires its accounting and control. For this, expensive geodetic methods are widely used, while accounting and control must be performed with high accuracy and frequency. In practice, the use of terrestrial stereophotogrammetric survey can provide a high frequency and accuracy of the results obtained. The traditional stereophotogrammetric survey at this stage undergoes significant changes with the introduction of digital technologies, which allow it to be used more widely. It is proposed to use non-metric digital cameras when performing terrestrial stereophotogrammetric surveys, which will let to reduce the cost of performing the measurement works, as well as to increase the efficiency of field works. The main indicator of the possibility of using the non-metric digital cameras is their resolution, which allows ensuring the accuracy of definitions and acceptable parameters for their calibration.