bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic modeling of a flexible beam with large overall motion and nonlinear deformation using the finite element method
Authors: He Xing-Suo  , Deng Feng-Yan  , Wu Gen-Yong  , Wang Rui  ,   西北工业大学工程力学系，西安  710072
Published: December 2020

In this paper, the dynamic modeling theory of a flexible beam, which incorporates large overall motion and nonlinear deformation, is investigated. As we knows, in spacecraft and space station, there are a lot of flexible appendices, the dynamic modeling of a flexible beam is essential. Yet existing such models, in our opinion, lack several important coupling terms. This paper supplies these important coupling terms. It is reasonable to use geometrically nonlinear deformation fields to demonstrate and simplify a flexible beam undergoing large overall motion. In this paper, the finite element method is used for the system discretization and the coupling dynamic equations of flexible beam are obtained by Lagrange’s equations. The complete expression of stiffness matrix and all coupling terms are included in the dynamic equations. The second order coupling terms among rigid large overall motion, arc length stretch, lateral flexible deformation kinematics and torsional deformation terms are concluded in the present exact coupling model to expand the theory of one-order coupling model. The dynamic properties of a planar flexible rotating beam in the non-inertial reference frame are developed.
Effects of end groups on the rectifying performance in molecular devices
Authors: Deng Xiao-Qing  , Zhou Ji-Cheng  , Zhang Zhen-Hua  ,   (1)长沙理工大学物理与电子科学学院，长沙 410004; (2)中南大学能源科学与工程学院,长沙 410083; (3)中南大学能源科学与工程学院,长沙 410083；长沙理工大学物理与电子科学学院，长沙 410004
Published: December 2020

Based on the density-functional theory and the non-equilibrium Greens function method, a theoretical study of the electron transport for the systems consisting of the terphenyl molecule connected to two Au electrodes through end-group S (Se) is carried out. The results show that these systems have good rectifying performance and the maximum rectification ratio may reach approximately 6 at a bias of 2.8 V. The rectifying behavior is reduced significantly when one of the two S(Se) atoms located at right end of the molecule is replaced by H. The asymmetric coupling between the molecule and the metal interface leads to different spatial distributions of the MPSH and different shifts of molecular orbital energy levels under positive and negative biases, which is the mechanism of rectifying performance. The systems with S end-groups have obvious rectifying performance because the interaction between S and Au electrode is stronger than that between Se and Au electrode.
Finding conserved quantities of three-dimensional second-order nonlinear coupled dynamics systems by the extended Prelle-Singer method
Authors: Lou Zhi-Mei  ,   绍兴文理学院物理系,绍兴 312000
Published: December 2020

In this paper, the extended Prelle-Singer (P-S) method is employed to finding the conserved quantities of three-dimensional second-order nonlinear coupled dynamic systems, the determining equations, the constraint equations of integral factors and the general expression of conserved quantities are obtained. The calculation method of integral factors is disscussed. Finally, two conserved quantities of three-particles Tada crystal lattice problem are found by extended P-S method.
Lie-Mei symmetry and conserved quantities of Appell equation for a holonomic mechanical system
Authors: Li Yuan-Cheng  , Xia Li-Li  , Wang Xiao-Ming  , Liu Xiao-Wei  ,   (1)河南教育学院物理系,郑州 450046; (2)中国石油大学(华东)物理科学与技术学院,青岛 266555
Published: December 2020

The Lie-Mei symmetry and conserved quantities of Appell equation for a holonomic mechanical system are studied. On the basis of the Appell equation, we first obtain the Lie symmetry and the Mei symmetry for the equation and the conserved quantities deduced from them, then the definition and the criterion for Lie-Mei symmetry of Appell equation are presented. Lastly, the Mei conserved quantity and the Hojman conserved quantity are deduced from the Lie-Mei symmetry. An example is given to illustrate the application of the result.
Nonlinear vibration in metal plate excited by high-power ultrasonic pulses
Authors: Chen Zhao-Jiang  , Zhang Shu-Yi  , Zheng Kai  ,   南京大学声学研究所，近代声学教育部重点实验室,南京 210093
Published: December 2020

Nonlinear vibration phenomena including superharmonics, subharmonics, quasi-subharmonics and chaos in metal plate excited by intensive ultrasonic pulses are studied experimentally and theoretically. In the experiments, the plates are excited by the ultrasonic pulse modulated high frequency vibration, and the nonlinear vibration velocities of the plates are measured by laser vibrometer for different sizes and fixing conditions of the plates. The analysis of time series, frequency spectrum and phase space are also performed to characterize the nonlinear vibration of the plate. According to the experimental conditions, a vibro-impact model with nonlinear contact damping is presented to explore the generation mechanism of the complicated nonlinear vibration in the plate. In the dynamic model, the intermittent vibro-impact between the ultrasonic transducer horn and plate are considered as the main source for generating the strongly nonlinear vibration in the plate. The numerical calculation results are in agreement with the observed experimental phenomena.
Hetero-structure coherent epitaxial growth in AlN/NbN nano-structured multilayers
Authors: Yu Li-Hua  , Xue An-Jun  , Dong Song-Tao  , Xu Jun-Hua  ,   江苏科技大学材料科学与工程学院,江苏省先进焊接技术重点实验室,镇江 212003
Published: December 2020

Monolithic AlN，NbN films and AlN/NbN multilayers with different modulation periods were prepared by reactive magnetic sputtering. The films were characterized by X-ray diffraction, X-ray reflectivity and high-resolution transmission electron microscopy. The results showed that the crystal structure of monolithic AlN and NbN films is close-packed hexagonal (hcp) and face-centered cubic (fcc), respectively. The crystal structure of AlN and NbN is hcp and fcc, respectively, in AlN/NbN multilayers. The interfaces between AlN layers and NbN layers are coherent， i.e., c-NbN (111)∥h-AlN(0002). The lattice mismatch of AlN/NbN multilayers is 013%. The thermodynamic calculation revealed that no matter how thickness of AlN or NbN layer is, the AlN layer does not form nonequilibrium structure of fcc, but the equilibrium structure of hcp. The AlN layers grow in the way of hetero-epitaxial coherent growth with NbN layers.
Structural transformation of multiwalled carbon nanotubes under γ-ray irradiation
Authors: Yang Tong-Zai  , Luo Shun-Zhong  ,   中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

Purified multiwalled carbon nanotubes (MWCNTs) were irradiated by 60Co γ-ray with different doses. The structural change of the MWCNTs was revealed by high-resolution transmission electron microscopy and Raman spectroscopy. It was found that under γ-ray irradiation some amorphous structure homogeneously covers the inner tube walls with graphite structure in irradiated MWCNTs. Moreover, the amorphous structure continuously proceeds and the graphite structure is reduced during the γ-ray irradiation till the irradiated MWCNTs become amorphous nanowires with a hollow structure. Based on the interaction between photons and carbon nanotubes, the structural transformation process and the corresponding mechanisms are discussed. In MWCNTs, the collision of a photon with a carbon atom will result in displacement of the atom, i.e. formation of a vacancy (single- or multi- vacancy) and a number of primary knock-on atoms which, if their energy is high, leave the tube or displace other atoms in the MWCNTs. If their energy is low, they can be adsorbed onto the tube walls. These adsorbed atoms play the role of interstitials. All the displaced atoms can be sputtered from the MWSNTs. The carbon atoms sputtered from the MWCNTs can further create some damage in a nearby MWCNTs or be absorbed onto its surface. Along with the simple defects, a number of more complex defects can be formed. The behavior of complex irradiation-induced defects is governed in part by annealing and diffusion of original defects-vacancies and interstitials. The γ-ray irradiation induced structural transformation of MWCNTs was a unique graphite to amorphous structural transition from the outer walls to the inner walls of the irradiated MWCNTs due to the removal of carbon atoms by knock-on displacements.
First-principles study of the multilayer relaxation of Cu stepped surfaces
Authors: Zhang Jian-Min  , Xu Ke-Wei  , Shu Yu  , Wang Guo-Hong  ,   (1)College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China; (2)State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China; (3)The Science Institute, Air Force Engineering University, Xi'an 710051, China
Published: December 2020

Using the pseudopotential plane wave (PPPW) method, we performed first principles calculation for the multilayer relaxations and the electron properties of the high-Miller-index stepped Cu(311), (511), (331) and (221) surfaces, which are expressed by 2(100)×(111), 3(100)×(111), 3(111)×(111) and 4(111)×(111), respectively, in the terrace-step notation, i.e. n(hkl)×(uvw). The interlayer relaxations of them are -+-…, --+-…, --+-… and ---+-…, respectively, which follow the atom-row trend: for stepped Cu surface which has n atom rows in the (100) or (111) terrace, the outermost n－1 interlayer spaces contract, then the n interlayer space expands, and the following n+1 interlayer space contracts again. For the stepped surfaces with the same (hkl)×(uvw), the larger the number of atom rows n in the terrace, the greater the contraction magnitude for Δd1,n. We did not find any indication of anomalous relaxation behavior for Cu(511) and (331) as mentioned in some references. Below Fermi energy level, the density of states of the first layer atom at stepped edge has the largest peak value in higher energy regions and has no peak in lower energy regions, so the first layer atom is most unstable and can be dislodged and peeled off more easily than other surface atoms. For the stepped surfaces with the same (hkl)×(uvw), the curves of the density of states have similar shapes for the atoms at the step edge, at the corner, at the terrace and near the corner, and the atoms under the step edge and near the corner.
First-principles study on electronic structure and optical properties of anatase TiO2 codoped with nitrogen and iron
Authors: Zhang Xue-Jun  , Gao Pan  , Liu Qing-Ju  ,   (1)Key Laboratory of Nanomaterials & Nanotechnology of Yunnan Province, College of Physical Science and Technology, Yunnan University, Kunming 650091, China; (2)Key Laboratory of Nanomaterials & Nanotechnology of Yunnan Province, College of Physical Science and Technology, Yunnan University, Kunming 650091, China; Department of Physics and Electric Information Engineering, Hunan City University, Yiyang 413000, Ch
Published: December 2020

The crystal structure, electronic structure and optical properties of nitrogen and iron codoped anatase TiO2 were studied by using the plane-wave ultrasoft pesudopotentials method based on density functional theory. The calculated results show that the octahedral dipole moments in nitrogen and iron codoped TiO2 increase due to the changes in lattice parameters, bond length and charge of atoms, which is very effective for the separation of photoexcited electron-hole pairs and the improvement of the photocatalytic activity of TiO2. Some impurity energy levels of codoped TiO2 are below the conduction band minimum, and others are above the valence band maximum. The distance between them is narrowed, which results in the redshift of the optical absorption edges to visible-light region. These impurity energy levels can reduce the recombination rate of photoexcited carriers and improve the photocatalytic efficiency of TiO2. Compared with that of Fe doped TiO2, for the codoped TiO2, the density of states peak of impurity energy levels above the valence band maximum increase apparently, which increases the electronic transition probability from the impurity energy levels to the conduction band, and improves the solar energy utilization. If the impurity level is not taken into account, compared with that of pure TiO2, the CB edge position and the VB edge position of codoped TiO2 is only slightly changed, it means that the strong redox capacity of codoping photocatalysts is still excellent.
Characteristics of dielectric resonators for high-transition-temperature radio frequency superconducting quantum interference devices
Authors: Gao Ji  , Yang Tao  , Ma Ping  , Dai Yuan-Dong  ,   State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
Published: December 2020

At present, the high-transition-temperature radio frequency superconducting quantum interference device (High- T c RF SQUID) is usually coupled to a dielectric resonator which is a standard 10 mm×10 mm× 1 mm SrTiO3 (STO) substrate with a YBa2Cu3O7-δ (YBCO) thin-film flux focuser deposited on it. The dielectric resonator for the High- Tc RF SQUID has a high quality factor and a resonant frequency in the microwave range. In order to find out the effect of the flux focuser’s geometry on the dielectric resonator’s resonant frequency, we used ANSOFT high frequency structure simulator (ANSOFT HFSS) to simulate the resonance characteristics of some dielectric resonators with different flux focuser geometries. Our simulation results show that when the width of the flux focuser’s slit increases or the radius of the flux focuser’s inner hole decreases, the dielectric resonator’s resonant frequency increases. To estimate the reliability of our simulation results, we selectively prepared a few dielectric resonators and measured their resonance characteristics. The experimental results are virtually consistent with the simulation results. Our study shows that changing the flux focuser geometry is an effective way to adjust the dielectric resonator’s resonant frequency.
Infrared multi-photon quantum cutting of Er-doped nanophase oxyfluoride vitroceramics
Authors: Zhang Chun-Lin  , Chen Xiao-Bo  , Yu Chun-Lei  , Hu Li-Li  , Pan Wei  , Wu Zheng-Long  , Liao Hong-Bo  ,   College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China;,   Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   Key Laboratory of Applied Optics of Beijing, Beijing Normal University, Beijing 100875, China;,   Shanghai Research Center of High Power Laser Glass, Chinese Academy of Sciences, Shanghai 201800, China;,   Shanghai Research Center of High Power Laser Glass, Chinese Academy of Sciences, Shanghai 201800, China; Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

The article reports the infrared quantum cutting phenomenon of the Er-doped nanophase oxyfluoride vitroceramics (Er(3):FOV). The infrared and visible fluorescence spectra of Er(3):FOV are measured carefully. It is found that the approximate quantum cutting efficiency of the 1543.0 nm 4I13/2→4I15/2 fluorescence, when the 2H11/2 levels are excited, is about 186.28%. The relative nonradiative relaxation rate and spontaneous emission rate and energy transfer rate are calculated. The relative energy transfer dynamics is analyzed. It is found that the {2H11/2→4I9/2, 4I15/2→4I13/2} energy transfer channel, with the rate of 371000 s-1, is the main reason for 2H11/2 energy level to have high quantum cutting efficiency. To our best knowledge, the present article for the first time reports Er(3):FOV to have an effective three-photon infrared quantum cutting excited by visible light and a four-photon infrared quantum cutting excited by near-violet light.
Research progress of applications of acoustic-vortex information
Authors: Guo Zhong-Yi , Liu Hong-Jun , Li Jing-Jing , Zhou Hong-Ping , Guo Kai , Gao Jun ,   School of Computer Science and Information Engineering, Hefei University of Technology, Hefei 230009, China
Published: December 2020

The orbital angular momentum (OAM) carried by acoustic vortex beam can be transmitted to objects, which has a good application prospect in particle manipulation. In addition, the acoustic vortex beam also has great potentials in acoustic communication. The acoustic vortex beams with different OAM modes are orthogonal to each other, so the OAM mode can be introduced into the traditional acoustic communication, which provides a potential solution for realizing the high-speed, large-capacity and high-spectral efficiency of underwater acoustic communication technology in future. In this paper, we summarize the research progress of acoustic vortex beam, in which we mainly introduce the generation and detection scheme of acoustic vortex beam, its transmission characteristics, and its typical research cases in communication. Finally, the future development trend and the outlook of acoustic vortex beam are also analyzed and prospected.
A gustatory receptor tuned to the steroid plant hormone brassinolide in Plutella xylostella (Lepidoptera: Plutellidae)
Authors: Yang Ke , Gong Xin-Lin , Li Guo-Cheng , Huang Ling-Qiao , Ning Chao , Wang Chen-Zhu
Published: December 2020

Feeding and oviposition deterrents help phytophagous insects to identify host plants. The taste organs of phytophagous insects contain bitter gustatory receptors (GRs). To explore their function, the GRs inPlutella xylostellawere analyzed. Through RNA sequencing and qPCR, we detected abundantPxylGr34transcripts in the larval head and adult antennae. Functional analyses using theXenopusoocyte expression system and 24 diverse phytochemicals showed that PxylGr34 is tuned to the canonical plant hormones brassinolide (BL) and 24-epibrassinolide (EBL). Electrophysiological analyses revealed that the medial sensilla styloconica of 4thinstar larvae are responsive to BL and EBL. Dual-choice bioassays demonstrated that BL inhibits larval feeding and female oviposition. Knock-down of PxylGr34 by RNAi attenuates the taste responses to BL, and abolishes BL-induced feeding inhibition. These results increase our understanding of how herbivorous insects detect compounds that deter feeding and oviposition, and may be useful for designing plant hormone-based pest management strategies.
Profissionais de Secretariado: caracterização do perfil requerido pelos empregadores portugueses
Authors: Ribeiro Sílvia Isabel do Rosário , Calvão Ana Rita Paçó , Simões Anabela Valente
Published: December 2020

Este trabalho apresenta os resultados da análise de 844 anúncios de emprego para a área de Secretariado, publicados, em Portugal, no Jornal Expresso (formato papel), entre 1978 e 2018 e tem como objetivo geral identificar o perfil de profissional desta área procurado pelos empregadores durante estas quatro décadas. Sabendo que o profissional de Secretariado tem, atualmente, responsabilidades e características bastante diferentes das que lhe eram próprias no passado, este trabalho tem como objetivos específicos identificar alterações nos requisitos (idade, género, formação e experiência) presentes nos anúncios em análise e rastrear o espectro de competências – técnicas e transversais – mais relevantes para os empregadores. Os resultados confirmam mudanças significativas, nomeadamente no que concerne às profissões procuradas, ao género dos profissionais, ao domínio de ferramentas e técnicas de apoio à função, com o aparecimento e progressiva solicitação das ferramentas informáticas, bem como no que respeita às competências transversais mais valorizadas.
Didática de ensino aplicada por docentes-secretários executivos: quais as percepções de discentes?
Authors: Pinheiro Barros Conceição de Maria , Silva José Nardel Oliveira da , Rocha Letícia Santos da
Published: December 2020

A docência na educação superior emerge como área de atuação secretarial e evidencia desafios relacionados ao domínio de conhecimentos pedagógicos. Esta pesquisa tem como objetivo analisar as percepções de discentes de Secretariado Executivo sobre as práticas de ensino de docentes-secretários executivos. Realizou-se uma pesquisa qualitativa e descritiva com a participação de 46 estudantes do curso de Secretariado Executivo de uma Universidade Federal do Nordeste. A coleta de dados foi realizada em dois momentos. O primeiro momento utilizou a aplicação de questionário. Na segunda fase, recorreu-se à técnica de entrevista. A interpretação dos dados foi feita por meio da análise de conteúdo. Os resultados denotaram que a didática de ensino aplicada pelos professores secretários executivos visa estratégias participativas e inclusivas, bem como uma fusão entre o mundo real e as leituras, ao englobar experiências reais. Os docentes-secretários possuem um vínculo com o Curso e a profissão, o que contribui para a construção de conhecimentos específicos e para a relação professor-aluno. Porém, a didática aplicada por secretários executivos que se tornam docentes é marcada por diversos desafios oriundos da ausência de uma formação pedagógica. Na perspectiva dos discentes, ainda existem desafios a serem superados em relação às estratégias, a fim de que promovam um ensino que atenda às necessidades dos educandos.
An Autopsy Case Report of Von Hippel-Lindau Syndrome-Type 2C Masquerading as Pre-eclampsia and Resulting in Maternal and Foetal Mortality
Authors: Fernandes Gwendolyn , Deshpande Varsha
Published: December 2020

A 23-year-old female with seven months pregnancy, presented with gestational hypertension associated with mild proteinuria and was diagnosed clinically as pre-eclampsia and referred to tertiary care centre. She also had progressive breathlessness and giddiness. On examination, pallor, Blood pressure (BP) of 180/100 mm Hg and crepitations in left lower lung were noted. Laboratory investigations revealed neutrophilic leucocytosis and a profile of Disseminated Intravascular Coagulation (DIC). An ultrasound (USG) of the abdomen showed a gravid uterus with Intrauterine Foetal Death (IUFD) and a left adrenal mass. The clinical diagnosis was acute hypertensive heart failure with severe pre-eclampsia. She was put on three anti-hypertensives and ventilatory support, but she succumbed to her illness, within three days of admission. A complete autopsy was performed. The autopsy revealed hypertensive heart disease with marked left ventricular hypertrophy, severe coronary atherosclerosis, cystic bilateral adrenal pheochromocytoma, a cystic para-aortic paraganglioma, a pancreatic Neuroendocrine Tumour (NET) with lymph node metastasis. Hence, a diagnosis of DIC with refractory hypertension in Type 2C Von Hippel-Lindau (VHL) syndrome was established. VHL syndrome is an autosomal dominant disorder caused by germline VHL mutation which leads to development of various tumours. VHL disease is classified into four subtypes and VHL type 2C has predominantly pheochromocytomas without haemangioblastoma and Renal Cell Carcinoma (RCC). As the patient mimicked pre-eclampsia clinically, the diagnosis of VHL was missed. Bilateral adrenal cystic masses with gestational hypertension should be thoroughly evaluated, at the earliest, for familial pheochromocytomas or VHL syndromes as they may prove fatal.
Assessment of Complete Blood Counts of Cannabis sativa Smokers in Ekpoma, Edo State, Nigeria
Authors: Amaechi R. A. , Babatope I. O. , Abulele P. O. , Obodo B. N.
Published: December 2020

Smoking of Cannabis sativa (Marijuana), a known psychoactive substance may result in side effect on living cells of the system. The aim of this study is to assess the complete blood count of Cannabis sativa smokers and make comparison with non-smokers in Ekpoma, Edo State. A total of one hundred subjects were recruited for this study which consist of Fifty (50) Cannabis sativa smokers and fifty (50) non Smokers which served as control. A complete record of medical and smoking history was obtained for each subject, with the use of the questionnaire. The samples obtained were taken to the laboratory for analysis using Sysmex KX auto analyzer. The result showed that the levels of WBC, RBC, granulocytes, lymphocytes, monocytes, Haemoglobin, packed cell volume and platelet levels were significantly lower (p<0.05) in cannabis smokers as compared to the control. The MCV, MCH, MCHC, RDW, PDW and MPV values of cannabis smokers were significantly different (p<0.05) as compared to the control subjects. In conclusion, this study showed that haematological parameters of cannabis smokers differed significantly from non-smokers.
Effect of Environmental Factors on Successful in vitro Morphogenesis of Madhuca longifolia
Authors: Shirin Fatima , Bhadrawale Deepti , Singh Sonam , Panika Shalu , Gupta Trilok
Published: December 2020

Madhuca longifolia is a commercially important tree species commonly known as mahua. The livelihood of large populations of tribal people depends on collection of its flowers and seeds. Almost all the parts of Mahua are utilized in diversified uses like in industry as artificial sweetner, biodiesel, food products, in soap industry etc. In the present study, a successful attempt was made to establish in vitro cultures of Mahua from nodal segments and factors influencing in vitro morphogenesis were evaluated as propagation through seeds and cuttings encounters problems. Axillary bud break (64.44%) was successfully achieved by culturing nodal segments on Murashige and Skoogs (MS) medium supplemented with 3 mg l-1Benzyladenine (BA) in nodal explants collected during the months ofJuly-September (rainy season).Shoot multiplication with maximum number of shoots, maximum number of leaves and longest shoots was achieved on MS medium supplemented with 3 mg l-1 BA when a subculture cycle of 30 days was followed. On MS medium supplemented with 2 mg l-1 Indole-3-Butyric Acid (IBA), in vitro excised shoots were successfully rooted (55.55%) after 40 days. A two step method was employed for successful hardening of rooted plantlets. Firstly, the plantlets were transferred for one week in 1/2 strength of MS liquid medium. Then, the plantlets were transferred to root trainers containing soilrite soaked with inorganic salts of ½ strength MS medium. The hardened plantlets were acclimatized firstly in a mist chamber and then in polybags in shade house. The present study provides an effective means for in vitro shoot regeneration and plantlet formation through nodal segments of Madhuca longifolia, a commercially important tropical tree with multifarious uses.
An Analysis of Extent of Farm Mechanization in North Bank Plains Agro-Climatic Zone of Assam
Authors: Rajkhowa A. , Barman I. , Das P. K. , Deka S. D. , Sonowal A.
Published: December 2020

Farm mechanization plays an important role for effective utilization of inputs which ultimately increase the productivity of land and labour by reducing the drudgery in farm operations in agriculture. There has been a substantial progress in farm mechanization in India; however, its spread has not been equal in all states for various reasons. This study was conducted in Sonitpur and Udalguri districts under North Bank Plain Agro-Climatic Zone of Assam with 160 farmers to analyse the factors influencing the extent of farm mechanization across different farm size groups. The findings revealed that majority of marginal (64.86%), small (64.52%), medium (72%) and large (72.73%) farmers had medium level of farm mechanization. In case of pooled sample, majority (67.5%) of the respondents had medium level of farm mechanization. The findings of the study indicated that majority of the respondents belonged to medium mechanization category. It implies that concerned agencies/ organizations should put more efforts in accelerating the adoption of farm mechanization by the farmers for sustainable agricultural production. The findings of regression analysis showed that in case of pooled farmers 8 variables, viz. education level, occupational status, scientific orientation, economic motivation, cropping intensity, social participation, working capital availability and innovativeness significantly contribute towards the extent of farm mechanization. It implies that there is possibility for the extension agencies to manipulate these crucial factors in order to bring about desirable changes in the farm mechanization adoption behaviour of farmers.
Effect of Serum Progesterone (P4) Level at the Day of Human Chorionic Gonadotropin (HCG) Administration on the Outcome of Intracytoplasmic Sperm Injection and Fresh Embryo Transfer
Authors: Masry Yasmine El- , Gharib Ashraf Elmohamdy , Allah Manal Moustafa Abd
Published: December 2020

Our aim was to investigate the effect of different progesterone (P4) at day of triggering HCG on the outcomes of ICSI with fresh embryo transfer in cases who underwent controlled ovarian stimulation (COS). Pituitary desensitization done either with long agonist or antagonist pituitary desensitization protocols, then analyzing the effect of serum P4-hCG level on ICSI-fresh embryos transfer outcome including; number and quality of retrieved oocytes (OR), embryo number (ER) & quality and ongoing pregnancy outcomes. The cases are which continued their pregnancy till 12 weeks, aborted cases, ectopic pregnancy & cancelled cases (for different reasons).

Materials and Methods: This prospective cohort study was carried on 120 cases who underwent ICSI cycles for different causes and types of infertility. Controlled ovarian stimulation (COS) protocol and pituitary down-regulation either by; GnRH long agonist /antagonist protocols then, fertilization, embryo grading, embryo transfer and hormonal luteal support was done. Blood samples were taken on the day of hCG administration to measure P4 in all cases. All patients who got pregnant and continue till 12 weeks, they were categorized into 3 subgroups as regard serum P4 level: Group A: (P4< 0.5 ng/ml), Group B: (P4=O.5-I.5 ng/ml) & Group C: (P4 >I.5 ng/ml) and correlated with their ICSI outcome. The outcomes of ICSI-ET cycles in those cases were compared with 3 groups of P4 levels in the controlled ovarian stimulation with two protocols.

Results: P4 level had insignificant relation with number and quality of retrieved oocytes, fertilized embryo number and quality and endometrial thickness regardless the protocol of COS. The low and high levels of P4 both, had a detrimental effect on CPR, meanwhile, with no harmful impact on the ongoing pregnancy rate was noticed, regardless the protocol of ovarian stimulation. P4-hCG isn’t considered to be the only predictive measure of ICSI outcome. Highest CRP was noticed in cases with P4 level (0.5-I.5 ng/ mI) regardless the type of protocol used.
Advanced Identification and Characterization of Listeria Species in Egyptian Local Soft Cheese
Authors: Dapgh Amany N. , ELGedawy A. A. , Abouelhag Hussien A. , Mansour Asmaa S. , Gaber E. S. , Farahat Engy
Published: December 2020

Aims: one of the most important foodborne microorganisms is the Gram’s positive environmental wide spread Listeria spp. As the Listeria may be considered a public health concern so there is in needing to rapid, precise and reliable diagnosis of the organism in consumed food. The present study aimed to survey the presence of Listeria spp. among two popular consuming Egyptian white soft cheese using advanced biochemical, antibiotic susceptibility and molecular techniques.

Methodology: Listeria spp. was investigated in 155 samples of two white soft cheeses (70 kareish cheese and 85 Damietta cheese) collected from street vendors and retail markets in Giza. The existence of Listeria spp. was tested through cultural and the identification was confirmed biochemically by Vitek2 compact system as well as molecular identification via diplex real time PCR using species specific primers.

Results: The results of the study revealed the isolation of two Listeria spp. in a total number of 22 from155 samples (14.19%); 14 isolate out of 70 (20%) Kareish cheese while 8 isolates out of 85 (9.4%) Damietta cheese's samples. The 22 Listeria spp. isolates were differentiated into L. innocua 15 (68.18%), and L. monocytogenes 7 (31.81%) also their antimicrobial susceptibility was declared using advanced Vitek-2 compact system. The two Listeria spp. isolates were definitely confirmed by using diplex DNA hybridization real PCR technique.

Conclusion: Soft raw milk based cheese is a popular food in Egypt and looked on as a risk for foodborne bacteria contamination. The data of this study pointed out that there is a potential risk of infection with Listeria, especially the public health concern L. monocytogenes. The current study presented Vitek-2 compact system as advanced technique for not only for identification and differentiation of Listeria strains but also for their antimicrobial susceptibility. Furthermore the using of diplex real PCR technique gives a chance for quick and precise identification.
Methods for Retrospective Detection of Exposure to Toxic Scheduled Chemicals. Part B: Mass Spectrometric and Immunochemical Analysis of Covalent Adducts to Proteins and DNA
Authors: Noort Daan , van der Schans Marcel J. , Black Robin M.
Published: December 2020

In this article, an overview is presented of the methods that are currently available for retrospective detection of exposure to a number of chemical warfare agents (CWAs), based on adducts formed with macromolecules such as proteins. These methods can be applied for various purposes, e.g. diagnosis and dosimetry of exposure of casualties, confirmation of nonexposure, and verification of nonadherence to the Chemical Weapons Convention, health surveillance, and forensic purposes. The advantage of using protein adducts as biomarkers in comparison with free metabolites is that they are potentially much more long‐lived. The methods are predominantly based on liquid chromatography–mass spectrometry (LC–MS) analysis of enzymatic digests of the (modified) proteins or on selective removal of the specific adduct moiety from the protein, followed by gas chromatography–mass spectrometry (GC–MS) or LC–MS. Several of the methods have been successfully applied to actual cases and were shown to be highly retrospective.
Elemental and Isotopic Analyses in Forensic Sciences
Authors: Irrgeher Johanna , Bandoniene Donata , Draxler Johannes , Prohaska Thomas
Published: December 2020

The focus of this work is a comprehensive overview of analytical techniques for elemental and isotopic analyses applied in forensic science (i.e. linking crime scene evidence to a crime by applying analytical techniques). The article provides a short description of the spectroscopic techniques and an overview of selected applications. In addition to general forensics, applications in nuclear forensics, environmental forensics, and food forensics are covered. Selected applications are linked to reviews and selected publications, which should allow for an overview of the current approaches in forensic analytical chemistry. This is an update article of its first version published in 2014 by Prohaska and Draxler.1
Ambient Ionization for the Detection of Chemical Warfare Agents and Related Chemistries
Authors: McBride Ethan M. , Mach Phillip M. , Dhummakupt Elizabeth S. , Hollinshead Donna E. , Glaros Trevor
Published: December 2020

The generation of ions outside of a mass spectrometer in the absence of a vacuum, under normal atmospheric conditions, is referred to as ambient ionization. Although many ionization techniques meet this broad definition, the term ‘ambient ionization’ is typically reserved for ionization techniques that allow for in situ sample analysis requiring little to no sample preparation. This cascade of techniques was first realized in 2004 with the introduction of desorption electrospray ionization (DESI). Since then, a whole host of ambient ionization techniques, each with categorical applications, have been developed. This article focuses on the most popular ambient ionization techniques: DESI, direct analysis in real time (DART), and paper spray (PS) ionization as they relate to the analysis of chemical warfare agents (CWAs) and related chemistries.
The Study on Enhanced Superhydrophobicity of Magnesium Hydroxide Corrosion‐Resistant Coating on AZ31B after 8 Months
Authors: Zhang Yu , Feng Yu , Meng Xue , Wang Jinlei , Niu Baolong , Yan Hong
Published: December 2020

To improve the corrosion resistance of magnesium alloy, the superhydrophobic coating is prepared on AZ31B magnesium alloy by hydrothermal treatment and surface modification in the fluorosilane methanol solution. The effects of samples kept in sealable plastic bags for 8 months on the superhydrophobic properties and corrosion resistance of superhydrophobic samples are investigated. The results show that the water contact angle of the newly prepared superhydrophobic coating can reach 164° ± 2° and can be increased to about 180° after being stored for 8 months. Compared with the AZ31B matrix sample, the corrosion current density of the newly prepared superhydrophobic AZ31B sample is reduced by about four orders of magnitude. After 8 months of storage, the corrosion current density of the sample is further reduced by about one order of magnitude, and the corrosion voltage is further increased.
3D Imaging of Lithium Protrusions in Solid‐State Lithium Batteries using X‐Ray Computed Tomography
Authors: Hao Shuai , Bailey Josh J. , Iacoviello Francesco , Bu Junfu , Grant Patrick S. , Brett Dan J. L. , Shearing Paul R.
Published: December 2020

Solid‐state lithium batteries will revolutionize the lithium‐ion battery and energy storage applications if certain key challenges can be resolved. The formation of lithium‐protrusions (dendrites) that can cause catastrophic short‐circuiting is one of the main obstacles, and progresses by a mechanism that is not yet fully understood. By utilizing X‐ray computed tomography with nanoscale resolution, the 3D morphology of lithium protrusions inside short‐circuited solid electrolytes has been obtained for the first time. Distinguishable from adjacent voids, lithium protrusions partially filled cracks that tended to propagate intergranularly through the solid electrolyte, forming a large waved plane in the shape of the grain boundaries. Occasionally, the lithium protrusions bifurcate into flat planes in a transgranular mode. Within the cracks themselves, lithium protrusions are preferentially located in regions of relatively low curvature. The crack volume filled with lithium in two samples is 82.0% and 83.1%, even though they have distinctly different relative densities. Pre‐existing pores in the solid electrolyte, as a consequence of fabrication, can also be part‐filled with lithium, but do not have a significant influence on the crack path. The crack/lithium‐protrusion behavior qualitatively supports a model of propagation combining electrochemical and mechanical effects.
Selective Synthesis of Benzothiophene‐Fused Polycyclic, Eight‐Membered N‐Heterocycles via Amine‐Mediated Three‐Component Domino Strategy
Authors: Deng Qingsong , Yu Aimin , Zhang Lei , Meng Xiangtai
Published: December 2020

A product‐selective strategy was used to synthesize benzothiophene‐fused polycyclic, eight‐membered N‐heterocycles via a three‐component domino reaction of thioisatins under catalyst‐free conditions. The reaction between tryptamine, thioisatin, and bromoacetophenone produced benzothiophene‐fused polycyclic compounds. In contrast, using D‐tryptophan methyl ester hydrochloride instead of tryptamine afforded benzothiophene‐fused eight‐membered N‐heterocycles. DFT calculations showed that the benzothiophene‐fused polycyclic compounds formed via the Pictet‐Spengler reaction. However, the ester group in D‐tryptophan methyl ester hydrochloride changed the reaction pathway and produced benzothiophene‐fused eight‐membered N‐heterocycles.

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Synthesis of Hydrophilic Phosphorus Ligands and Their Application in Aqueous‐Phase Metal‐Catalyzed Reactions
Authors: Schlatzer Thomas , Breinbauer Rolf
Published: December 2020

Transition metal‐catalyzed reactions in aqueous media are experiencing a constant increase in interest. In homogenous catalysis the use of water as a solvent offers advantages in cost, safety, the possibility of two‐phase catalysis and simplified separation strategies. In the life sciences, transition metal catalysis in aqueous systems enables the ligation or modification of biopolymers in buffer systems or even in their cellular environment. In biocatalysis, aqueous systems allow the simultaneous use of enzymes and transition metal catalysts in cascade reactions. The use of water‐soluble phosphine ligands still represents the most reliable and popular strategy for transferring metal catalysts into the aqueous phase. This review summarizes the recent advancements in this field since 2009 and describes current synthetic strategies for the preparation of hydrophilic phosphines and phosphites. In addition, recent applications of transition metal catalysis in aqueous solvents using these hydrophilic ligands are presented.

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Engineering an Alcohol Dehydrogenase from Kluyveromyces polyspora for Efficient Synthesis of Ibrutinib Intermediate
Authors: Wu Yanfei , Zhou Jieyu , Ni Jie , Zhu Cheng , Sun Zewen , Xu Guochao , Ni Ye
Published: December 2020

(S)‐N‐Boc‐3‐hydroxypiperidine [(S)‐NBHP] is a key intermediate for the synthesis of mantle cell lymphoma drug, ibrutinib. Here, KpADH, an alcohol dehydrogenase from Kluyveromyces polyspora, exhibits evolutionary potential in the asymmetric reduction of N‐Boc‐3‐piperidone (NBPO) to (S)‐NBHP. By screening key residues in substrate binding pocket of KpADH, an excellent variant Y127W was obtained with 6‐fold improved activity of 119.3 U mg−1, 1.8‐fold enhanced half‐life of 147 h and strict S‐stereoselectivity (>99% ee). When catalyzed by Y127W, a complete conversion of 600 g L−1 NBPO was achieved at a substrate to catalyst ratio (S/C) of 30 in 10 h. Based on crystal‐structure of Y127W, molecular docking and dynamic simulations reveal hydrogen bonds formed between W127 and Boc group of NBPO, as well as improved structural stability mainly contribute to the increased catalytic activity and stereoselectivity of Y127W. This study offers guidance for engineering ADHs for biosynthesis of chiral heterocyclic alcohols, and provides insights into mechanisms in catalytic activity and stereoselectivity toward carbonyl‐containing heterocyclic substrates.

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Deep Mining of Subtle Differences in Cell Morphology via Deep Learning
Authors: Xue Yunfan , Wang Jing , Ren Kefeng , Ji Jian
Published: December 2020

Cell morphology analysis is crucial in life science. Accurate determination of differences in cell morphology is of great significance in understanding cell states under different conditions. However, conventional approaches for morphology analysis are constrained in efficiency or accuracy under many circumstances. Thus, an efficient and reliable method to profile morphological differences is needed. In this study, deep learning is used in cell image analysis to demonstrate its ability to find non‐apparent cell morphology differences. The convolutional neural network can accurately classify cell images from substrates of different stiffness that are undistinguishable to the human eye or conventional statistical methods. Moreover, with analysis of feature maps, and the assistance of a fully connected neural network and a random forest classifier, morphological information in images is systematically proved as the main basis of classification for the deep learning model. The above results indicate that deep learning is valuable for the in‐depth analysis of morphology to better understand subtle changes in cells, which can provide people with deeper insights into cell biology.
Does Trade Policy Uncertainty Affect Agriculture?
Authors: Gopinath Munisamy
Published: December 2020

This article reviews evidence of trade war impacts and emerging concerns on trade policy uncertainty. Trade war's near‐perfect pass‐through of tariffs to US prices favored producers and generated government revenue at the expense of consumers. Facing retaliation, prices and trade volumes were found to be lower for US agricultural commodities. The recent rethink on the benefits of globalization by major economies has led to uncertain policy paths wherein firms and consumers continue to make decisions. Using quarterly data, a negative association between policy uncertainty and agricultural economic indicators is affirmed with implications for future evaluation of trade war impacts.
Advantageous factors of R0 curative conversion esophagectomy and the optimal extent of lymphadenectomy after induction therapy for cT4b thoracic esophageal cancer
Authors: Ohkura Yu , Ueno Masaki , Udagawa Harushi
Published: December 2020

Aim

This study aimed to clarify the prognostic factors, the advantageous factors of R0 curative resection, and optimal extents of lymph node dissection for conversion esophagectomy after induction therapy.

Methods

Among 1903 patients with esophageal cancer at Toranomon Hospital between January 2006 to May 2020, 151 patients with locally advanced T4b thoracic esophageal cancer were divided into two groups according to treatment: conversion surgery group (n = 54) and non‐surgical treatment group (n = 97) for comparison.

Results

The patients who underwent R0 curative resection showed preferable survival comparable to the survival rate of patients with cCR in the non‐surgical treatment group (1‐, 3‐ and 5‐year survival: 96.9%, 82.1% and 76.7% vs 94.1%, 86.3%, and 86.3%; P = 0.770). Multivariate analysis revealed that the T4b tumor invasion by primary site (odds ratio (OR) = 6.100; 95% CI, 1.439‐25.865: P = 0.014) and time to conversion surgery from start of induction therapy within four months (OR = 5.229; 95% CI, 1.296‐21.102: P = 0.020) were all independent advantageous factors of R0 curative resection. Actuarial 1‐, 3‐ and 5‐year survival rates in patients who underwent conversion surgery with D2‐3 lymphadenectomy were 90.9%, 48.6%, and 40.8%, respectively.

Conclusions

R0 resection led to improved prognosis in conversion esophagectomy for cT4b esophageal cancer. The T4b tumor invasion by primary site and time to conversion surgery from start of induction therapy within 4 months were independent advantageous factors of R0 curative resection. In addition, standard radical esophagectomy including prophylactic D2‐/3‐ lymphadenectomy should be performed if it is possible, while taking adequate care regarding the increased risk after induction therapy.
Case report: Maternal tyrosinemia type 1a under NTBC treatment with tyrosine‐ and phenylalanine restricted diet in Chile
Authors: Medina María F , Arias Carolina , Cabello Juan F , De la Parra Alicia , Valiente Alf , Castro Gabriela , Fuenzalida Karen , Cornejo Verónica
Published: December 2020

We report the case of a 17‐year‐old girl with Tyrosinemia type 1a who carried a planned pregnancy to term while being under 2‐(2‐nitro‐4‐trifluoromethylbenzoyl)‐1,3‐cyclohexanedione (NTBC, nitisinone) treatment and a tyrosine‐ and phenylalanine‐restricted diet. She was on treatment since 2 months of age with poor metabolic control prior to her pregnancy (tyrosine 838 ± 106 umol/L). NTBC and a low tyrosine and phenylalanine diet were continued during her pregnancy. She unfortunately suffered from urinary tract infection and anemia during her pregnancy, with median plasma tyrosine and phenylalanine levels of 613 ± 106 umol/L (200–400 umol/L) and 40.2 ± 8 umol/L (35–90 umol/L), respectively. After 40 weeks of gestation, the patient gave birth to a healthy boy, with no adverse effects related to the use of NTBC. The newborn presented with a transitory elevation of plasma tyrosine levels and normal phenylalanine, methionine, and succinylacetone levels. By 12 months of age, the child was determined to have normal psychomotor development. At 20 months old, he was diagnosed with a mild developmental delay; however, global cognitive evaluation with the Wechsler Intelligence Scale for Children (WISC) test at 5 years old showed normal performance. Here, we discuss one of the few reported cases of nitisinone treatment during pregnancy and demonstrate a lack of teratogenicity and long‐term cognitive disabilities.