bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic theoretical study on sensing behaviors of defects and doping coexistence of black phosphorene to formaldehyde
Authors: Zhang Guo-Ying , Jiao Xing-Qiang , Liu Ye-Shu , Zhang An-Guo , Meng Chun-Xue ,   College of Physics Science and Technology, Shenyang Normal University, Shenyang 110034, China,   College  of Life and Health Sciences, Northeastern University, Shenyang 110819, China
Published: December 2020

Black phosphorene (BP) has a high specific surface area due to its puckered honeycomb lattice structure, so it has great advantages in gas sensor applications. Doping and defects have a great effect on its sensitivity. Our aim is to obtain an insight into the sensing mechanism of black phosphorene towards CH2O, a hazardous organic compound. Based on the first-principles method of density functional theory (DFT), the sensing behaviors of the BP system, with intrinsic, Al doped, P vacancy-defected and P-vacancy and Al doping coexistent, before and after CH2O adsorption are studied. By establishing the structural models of four BP systems, the values of adsorption energy, energy band structure and charge transfer are calculated. Calculation results show that CH2O molecule prefers to be adsorbed perpendicular to the P vacancy-defected BP nanosheet with oxygen atom on the top site and close to the sheet. For the intrinsic, Al doped, P-vacancy and Al doping coexisting BP nanosheet, the CH2O molecule tilts towards the sheet surface. It is found that the CH2O adsorption on intrinsic BP nanosheet (adsorption energy is 0.179 eV) is very weak. In contrast, the adsorption of CH2O to the BP systems, with P vacancy-defected BP, Al doped, P-vacancy and Al doping coexistent, shows relatively high affinity (0.875, 0.542, 0.824 eV). Thus, Al doping, P vacancy or P-vacancy and Al-doping coexistence can substantially improve the adsorption ability of BP systems towards CH2O. In order to investigate the sensing mechanism of BP systems, the electronic properties such as the density of states, energy band and charge transfer are calculated. The change of energy gap of intrinsic BP nanosheet before and after CH2O adsorption is 0.024 eV, and that for P vacancy-defected BP nanosheet is zero. In addition, P atom vacancy has no effect on charge transfer. These suggest that the conductivity of intrinsic BP or P vacancy-defected BP nanosheet has not obviously changed, thereby, they are not suitable for sensor materials. For the BP system with Al doping or the coexistence of P vacancy and Al doping, it is obviously seen that an impurity level is generated in the energy band diagram, the effective band gap is significantly narrowed, indicating that the Al doping improves the sensitivity of BP. In addition, the charge transfer is significantly increased, which changes the carrier concentration and improves the electrical conductivity. Therefore, the BP system with Al doping or the coexistence of P vacancy and Al doping is expected to become a kind of new sensor material.
Design and experiment of X-band high-repetition rate high-power multi-beam relativistic klystron amplifier
Authors: Liu Zhen-Bang , Huang Hua , Jin Xiao , Wang Teng-Fang , Li Shi-Feng ,   Science and Technology on High Power Microwave Laboratory, Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The relativistic klystron amplifier (RKA) is a very important kind of high power microwave device, which has the advantages of high power, high efficiency, stable output phase and amplitude. The development of multi-injection RKA toward engineering and practical application needs to further improve operating frequency and output power of klystron amplifier, while the RKA of conventional circular waveguide drift tubes is restricted by the physical factors such as geometric size, space charge force and high-voltage breakdown. The multi-beam RKA based on the technology of multiple electron beams can work at low voltage and guiding magnetic field, and can also possess high electron beam current and diversion coefficient. The physical limitation of conventional structure RKA is overcome, and the working frequency and the output power are improved. In the experiment, the X-band GW level power of microwave is obtained. The multi-beam RKA needs to further improve its working frequency and working life. In the experiment, the power conversion efficiency of multi-beam RKA is about 35%, and most of the remaining electron energy will accumulate on the collection pole at the end. If the heat dissipation of the collector is not designed appropriately, the collection will be seriously ablated when working at high heavy frequency. Thus a large quantity of plasma and secondary electrons are generated, which affects the stability of the device. To solve the problem of electron reflux bombarding the output cavity after electron beam exchanging energy in the gap of output cavity, the reflux process of relativistic electron beam in the device is analyzed in this paper. On this basis, a coaxial extraction structure with four-gap extension interaction is designed to avoid electron reflux and reduce the gap electric field, thus improving the working life of the device. At the same time, in order to solve the problem that the conventional water cooling channel can affect the output microwave mode in a high-frequency over-mode device, a mode transformation structure of coaxial TEM mode-fan-shaped TE10 mode-coaxial TEM mode-circular waveguide TM01 mode is designed. The mode conversion efficiency is greater than 99.9%, and the influence of collecting polar water cooling channel on the output microwave mode is avoided. The stable operation of multi-beam RKA in the X-band with a repetition rate of 45 Hz is realized experimentally, while the output power is over 1 GW and the microwave pulse width is over 100 ns. At present, the multi-beam RKA runs about 10000 times in total, and the output microwave parameters do not decrease significantly.
New advances in biomedical applications of multiphoton imaging technology
Authors: Li Shao-Qiang , Geng Jun-Xian , Li Yan-Ping , Liu Xiong-Bo , Peng Xiao , Qu Jun-Le , Liu Li-Wei , Hu Rui ,   College of Physics and Optoelectronic Engineering, Shenzhen University, Ministry of Education/ Guangdong Key Laboratory of Optoelectronic Devices and Systems, Shenzhen 518060, China
Published: December 2020

In contrast to single photon excitation fluorescence imaging, laser scanning confocal imaging, and wide-field imaging, the multi-photon imaging has advantages of minimal invasion and deeper penetration by using near-infrared (NIR) laser source. Moreover, it can carry out three-dimensional high-spatial-resolution imaging of biological tissues due to its natural optical tomography capability. Since its advent, multi-photon imaging has become a powerful tool in biomedicine and achieved a series of significant discoveries in cancer pathology, neurological diseases and brain functional imaging. In the past decade, as a major form of multi-photon imaging techonoogy, two-photon excited fluorescence microscopy imaging has a great potential in biomedical applications. In order to satisfy the practical biomedical applications, multi-photon imaging technologies have made significant breakthroughs in improving the deficiencies of traditional 2PEF in multi-color imaging, functional imaging, live imaging and imaging depth, such as multicolor two-photon excitation fluorescence microscopy, two-photon fluorescence lifetime imaging microscopy, two-photon fiber endoscopic imaging, and three-photon microscopy imaging technology. For example, multicolor two-photon excitation fluorescence microscopy is demonstrated to achieve simultaneous imaging of multiple fluorophores with multiple wavelenth excitation lasers or continuous spectrum. In addition, the two-photon fluorescence lifetime microscopic imaging provides a method to achieve high-resolution three-dimensional imaging of biological tissue with multi-dimensional information including fluorescence intensity and lifetime. In addition, two-photon optical fiber endoscopic imaging with small system size and mimal invasion is developed and used to image the tissue inside the deep organ. Finally, two-photon excitation fluorescence microscopy technique still has relatively strong scattering for brain functional imaging in vivo. Therefore, the imaging depth is limited by the signal-to-background ratio. Three-photon microscopic imaging technique can achieve higher imaging depth and a desired signal-to-noise ratio by extending the wavelength from 1600 nm to 1820 nm because the attenuation of the excitation light in this wavelenth range is much smaller. In this article, we briefly introduce the principles and applications of these multi-photon imaging technologies, and finally provide our view for their future development.
Interference rings induced by ultrafast laser pulse in GaAs crystal
Authors: Shang Ling-Ling , Qian Xuan , Sun Tian-Jiao , Ji Yang ,   State key Laboratory of Supperlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China,   College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Gallium arsenide (GaAs) is an important semiconductor material with direct bandgap and clear-cut absorption edge. High-quality crystal is available, which has excellent performances in the field of high power transmission and luminescence because of high laser damage threshold and high thermal conductivity. Nonlinear optics is of great significance for developing the laser technology, spectroscopy, and optoelectronic devices. The Z-scan technology is a nonlinear measurement method based on the analysis of single beam transmittance. Previous studies mainly focused on the measurement of the nonlinear absorption coefficient of the sample by open-aperture configuration of Z-scan and the nonlinear refractive index of the sample by shut-aperture configuration of Z-scan. We build a dual-channel Z-scan system with variable optical path difference, equipped together with a high speed camera, to observe the spatial distribution of transmitted light. Besides, we find the interference rings induced by nonlinear absorption in semiconductor GaAs crystals. Using three kinds of lasers (continuous-wave laser, 80 MHz femtosecond pulsed laser, 1 kHz femtosecond pulsed laser) to illuminate the GaAs crystal separately, multi-level interference rings come out only when a GaAs crystal wafer is illuminated by a femtosecond pulsed laser. In the single-channel Z-scan experiment, we observe that the interference rings contract or expand regularly when changing pulsed laser intensity incident on the surface of GaAs crystal. The higher the intensity of pulse, the more interference rings appear, and the maximum exiting angle becomes larger. Nonlinear effect of high intensity femtosecond pulsed laser locally changes the refractive index of GaAs crystals, resulting in optical path difference (Kerr lens effect). However, the Kerr lens generated by ultrafast light pulse in GaAs crystal cannot focus a beam as done by an ideal thin lens, leading the transmitted light to form interference rings instead. By analyzing the variation of the interference rings, the nonlinear absorption coefficient and refractive index of GaAs crystal can be obtained. In the dual-channel Z-scan experiment, different interference rings are induced in the GaAs crystal as the path difference between the two pulses changes, as done by the nonlinear transmission power. Thus we obtain the formation time of the interference rings and ascribe it to the ultrafast relaxation process of GaAs carriers.
Superconducting and flux pinning properties of FeSexTe1–x topological superconductors
Authors: Liang Chao , Zhang Jie , Zhao Ke , Yang Xin-Sheng , Zhao Yong ,   School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China,   Superconductivity and New Energy R & D Center, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

Iron-based superconductor FeSexTe1–x has attracted attention because of its high upper critical field, low anisotropy, and high critical current density. Also, it is predicted to have nontrivial topological properties, so that it is a candidate of realizing Majorana fermion, when the superconductivity is combined with topological features. However, its flux pinning behavior and mechanism in superconducting state with varying Se/Te ratio have not been systematically studied . We use self-flux method to grow single crystal samples of FeSexTe1–x with different x values (0.3, 0.4, 0.5 and 0.6). The structural and morphological properties of the monocrystalline samples are characterized by XRD and SEM. All samples show that they possess the expected crystalline structures and their lattice parameters vary with x value. The magnetic properties at low temperatures are also measured, showing that all samples have good superconductivity. Superconducting properties, such as critical current densities and flux pinning force densities, are extracted from the magnetic measurements and analyzed, and the flux pinning behavior is discussed. The best Se:Te ratio is determined to be nearly 0.4/0.6 based on the comparison among these properties of different samples. By utilizing the Dew-Hughes theory and analyzing the pinning force density peak, the flux pinning mechanism in the best samples (x = 0.4, 0.5) can be regarded as the mixture of normal point pinning and Δκ volume pinning. This work provides important information for the further study of the topological and superconducting properties of FeSexTe1–x.
Anode interface in all-solid-state lithium-metal batteries: Challenges and strategies
Authors: Yu Qi-Peng , Liu Qi , Wang Zi-Qiang , Li Bao-Hua ,   Shenzhen Key Laboratory on Power Battery Safety Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China,   School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China,   Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
Published: December 2020

The developing of all-solid-state lithium-metal batteries promises to improve safety and energy density. The challenges in the anode|electrolyte interface are crucial and divided into static and dynamic issues in this review. The static issues are mainly shown as the huge resistances appearing in the assembled batteries, while the dynamic issues are reflected in the rapid deterioration of cycling performance. The static issues are mainly due to the poor chemical stability and interfacial contact, while dendrite growth and void formation are contained in the dynamic issues. Solving dynamic issues on the basis of static issues can conduce to the construction of stable all-solid-state lithium-metal batteries.
Development and applications of schlieren system for measuring characteristics of supersonic molecular beam
Authors: Yin Jiao , Xiao Guo-Liang , Chen Cheng-Yuan , Feng Bei-Bin , Zhang Yi-Po , Zhong Wu-Lü ,   Southwestern Institute of Physics, Chengdu 610225, China
Published: December 2020

Supersonic molecular beam injection (SMBI) is an effective fueling method for the magnetic fusion plasmas. The fueling method was first proposed in the HL-1 tokamak, and now has been applied to several tokamaks and stellarators. Pulsed molecular beam passes from a Laval type nozzle and has a high instantaneous intensity, high directionality and deep deposition in the plasma. The fueling efficiency is higher than the gas puffing efficiency. In addition, it is widely used for controlling plasma density and investigating plasma physics. To further improve the fueling capability in future fusion devices, it is highly desirable to optimize the characteristic of the SMB and further investigate the interactions between the molecular beam and the plasma. In this paper, a schlieren diagnostic system is developed to measure the parameters of molecular beam, and the testing application is performed. The schlieren system, which is based on the schlieren photography, is designed with the zigzag optical path and equipped on the SMBI testing platform to measure the characteristics of the supersonic molecular beam. In order to verify the effectiveness of the system, a series of tests is carried out with different nozzle shapes under atmospheric and vacuum conditions. The beam profiles of CO2 and D2 under different background pressures are obtained. The testing results indicate that the directionality of the integrated Laval nozzle is much better than that of the pinhole nozzle. The schlieren system provides a testing tool for optimizing the supersonic molecular beam.
Research progress of interface problems and optimization of garnet-type solid electrolyte
Authors: Zhang Nian , Ren Guo-Xi , Zhang Hui , Zhou Deng , Liu Xiao-Song ,   State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China,   Tianmu Lake Institute of Advanced Energy Storage Technologies, Liyang 213300, China,   School of Physical Science and Technology, Shanghai Tech University, Shanghai 201210, China
Published: December 2020

With the increasing demand for storage devices with higher energy output and better safety performance, all-solid-state batteries show their potential to replace the traditional liquid-based Li-ion batteries in the future storage market. Garnet-type Li7La3Zr2O12 is one of the most attractive solid electrolyte materials because of its high ionic conductivity and stability to lithium metal. However, the large interfacial resistance originating from the insufficient solid-solid contact and the penetration of the lithium dendrite due to the inhomogeneous dissolution and deposition of lithium, hinder the all-solid-state batteries from developing. Focusing on the main interfacial problems in garnet-type all-solid battery, this review provides a fundamental understanding of the Li2CO3 issues in Li7La3Zr2O12 solid electrolyte and addresses the key factors influencing Li/ Li7La3Zr2O12/cathode interfacial wettability and the growth of Li dendrite, thus giving the key factors of constructing ideal interfaces. Finally, the possible research direction of garnet-type all-solid-state battery in the future is also prospected, which provides a guidance for developing and using all-solid-state batteries.
Analysis of sound field distribution of angle dimension in deep ocean bottom bounce area and its application to active sonar vertical beam pitch
Authors: Han Zhi-Bin , Peng Zhao-Hui , Liu Xiong-Hou ,   University of Chinese Academy of Sciences, Beijing 100049, China,   State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China,   Unit 92578 of the People’s Liberation Army of China, Beijing 100161, China,   School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
Published: December 2020

In the deep ocean environment, the sound energy from the direct path is very hard to illuminate a target located in the shadow zone. To solve the problem, the bottom bouncing technique, in which the vertical transmitting beamforming and the bottom bouncing are used to illuminate the target in the shadow zone, provides a potential way. However, due to the sound field interference in the bottom bouncing area in the deep ocean environment, the sound energy in the bottom bouncing area is fluctuant, which produces several discrete detectable areas. In order to detect underwater targets in these areas when using an active sonar with a transmitting vertical linear array, the selecting of reasonable vertical transmitting beam angles is necessary. Therefore, the relationship between the discrete detectable area and the transmitting vertical angle in deep ocean is very important for the active sonar using a transmitting vertical linear array. In this paper, it is shown that the sound field fluctuation in the bottom bouncing area is due to the energy fluctuation of the rays having different grazing angles. And the active sonar can achieve high noise gain in a detectable area when the vertical transmitting angle is equal to the grazing angle of the sound ray with the peak energy. To obtain a high noise gain of the active sonar using the vertical transmitting array, an efficient method to estimate the grazing angle of sound rays with peak energy according to the sound field distribution of angle dimension is proposed, which is helpful for selecting a group of best vertical transmitting angles. Meanwhile, a transmitting signal which contains a group of subpulses is designed. Furthermore, each subpulse is applied to the whole transmitting array by using the vertical steering to illuminate a certain detectable area in the bottom bouncing area. By doing so, a subpulse steered to the previously selected vertical angle will ensure a high transmitting array gain in a detectable area, and all of pulses will illuminate the whole detectable areas with high array gains almost simultaneously. Numerical simulations show that the proposed method is stable and efficient, and has good noise gain in the shadow zone (where almost no direct path exists) in the deep ocean environment.
Residence-times distribution function in asymmetric bistable system driven by noise recycling
Authors: Wu Ya-Zhen , Sun Zhong-Kui ,   School of Mathematics and Information Technology, Yuncheng University, Yuncheng 044000, China,   Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an 710072, China
Published: December 2020

Residence-times distribution function (RTDF), as a distribution function of times between two consecutive switches in a bistable system, is extensively used to characterize the phenomenon of stochastic resonance (SR). However, most of the studies focus on the symmetric bistable systems. As a matter of fact, the majority of asymmetric systems encountered in nature are more universal and practical. Additionally, due to the combination of diverse propagations or transduction mechanisms, noise recycling, constituted by the superposition of a master noise with a secondary component delayed by a time shift τ, can be generated while a noise is injected into a system and transmitted across the system. Therefore, an asymmetric system subjected to noise recycling is no longer non-Markovian. As a result, it is essential to take the special correlation of noise recycling into account when studying the transition dynamics of particles, which makes it difficult to obtain the analytical formula of RTDF. To solve the above problem, a theoretical method to calculate the RTDF of an asymmetric bistable system driven by noise recycling is put forward in this paper. By using the two-state model with piecewise escape rate, the piecewise escape rate function can be established, based on which the RTDF is derived theoretically with a piecewise formula. It is emphatically demonstrated theoretically and numerically that the RTDF exhibits a feedback-induced structure due to the asymmetry of system. Meanwhile, the effects of relative strength and recycling lag on the structure of RTDF are investigated theoretically and numerically. The results are shown as follows: when the asymmetry satisfies γ > 0 and taking γ as the appropriate values, the RTDF decays exponentially and exhibits a sharp dip at t = τ. Nevertheless, on the contrary, under the condition for γ < 0, the dip at t = τ of RTDF almost disappears and the rate of decay of RTDF turns to increase. When the relative strength and recycling lag take the appropriate values separately, the RTDF displays piecewise exponential decay and declines sharply at t = τ. It is worth noting that the interval between discontinuities becomes smaller, or even disappears with the relative strength and recycling lag increasing separately. Further, the value of RTDF at t = τ presents a maximum value with the noise intensity and the relative strength varying, which illustrates that the noise recycling procedure can play a crucial role in inducing the phenomenon of SR in the asymmetric bistable system.
Brief introduction to flux pinning and vortex dynamics in high temperature superconductors
Authors: Wen Hai-Hu ,   Physics Department, Nanjing University, Nanjing 210093, China
Published: December 2020

Superconductivity is achieved through macroscopic phase coherence; the charge carriers are Cooper pairs. In absence of an external magnetic field and applied current, the behavior of these Cooper pairs can be described by a single wave function \begin{document}$ \psi = {\psi _{\rm{0}}}{e^{i\varphi }}$\end{document}, and the phase is uniform over the space. When applying an external field but still below a certain threshold, a screening current will be established at the surface, which prohibits the entering of magnetic field, that is so-called Meissner effect. When the external field is larger than this threshold, the magnetic flux will penetrate into the sample, forming the interface of superconducting and normal state regions. According to the sign of this interface energy, we can categorize superconductors into type-I (positive interface energy) and type-II (negative interface energy). Most superconductors found so far are type-II in nature. Due to the negative interface energy in type-II superconductors, the penetrated magnetic flux will separate into the smallest bundle, namely the quantum flux line, with a quantized flux \begin{document}${\varPhi _0} = h/2e$\end{document} (h is the Planck constant and e is the charge of an electron). There are weak repulsive interactions among these vortices, thus usually they will form a lattice, called mixed state. When applying a current, a Lorentz force will exert on the flux lines (vortices) and will make them to move, this will induce energy dissipation and the appreciable feature of zero resistance of a superconductor will be lost. By introducing some defects, impurities or dislocations into the system, it is possible to pin down these vortices and restore the state of zero resistance. The study concerning vortex pinning and dynamics is very important, which helps not only the understanding of fundamental physics, but also to the high power application of type-II superconductors. This paper gives a brief introduction to the vortex dynamics of type-II superconductors.
Instruction Sequence Faults with Formal Change Justification
Authors:   Informatics Institute, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands, Bergstra Jan
Published: December 2020

The notion of an instruction sequence fault is considered as a theoretical concept, for which the justification of the qualification of a fragment as faulty is mathematical instead of pragmatic, the latter approach being much more common. Starting from so-called Laski faults a range of patterns of faults and changes thereof for instruction sequences is developed.
Complexities of assessing palaeocave stratigraphy: reconstructing site formation of the ∼2.61 Ma Drimolen Makondo fossil site
Authors: Murszewski Ashleigh , Boschian Giovanni , Herries Andy I.R.
Published: December 2020

Palaeocave sites in South Africa are world renowned repositories for palaeontological and archaeological material, dating from the terminal Pliocene to the Early Pleistocene. Due to their antiquity, complex karstification history and multifaceted infilling phases, palaeocave sites are notoriously difficult to contextualise. Further to this, 19th century lime-mining and diverse excavation and sampling techniques, have complicated stratigraphic interpretations of fossil-bearing deposits within the region. Locating and assessing newly discovered, minimally disturbed palaeocave sites allow for contextual information to be gathered with greater confidence and can aid in constructing a more robust understanding of the South African fossil record. Here, we use Drimolen Makondo; a minimally lime-mined ∼2.61 Ma palaeontological site, to apply a series of in-depth stratigraphic and micromorphological studies. Contextual data presented within this study, testifies to a relatively rapid infill with greater fluvial activity when compared to adjacent deposits at the younger ∼2.04–1.95 Ma Drimolen Main Quarry. The quantity of articulated macromammalian remains, high density of micromammalian remains and pollen identified, also highlights Drimolen Makondo as a key site for ongoing palaeoenvironmental studies at the Pliocene to Pleistocene transition in South Africa.
Cinnamtannin B1 attenuates rosacea-like signs via inhibition of pro-inflammatory cytokine production and down-regulation of the MAPK pathway
Authors: Kan Hung-Lin , Wang Chia-Chi , Cheng Yin-Hua , Yang Chi-Lung , Chang Hsun-Shuo , Chen Ih-Sheng , Lin Ying-Chi
Published: December 2020

Background

Rosacea is a common inflammatory disease of facial skin. Dysregulation of innate immunity with enhanced inflammation and increased abundance of LL-37 at the epidermal site is a characteristic feature of rosacea. Cinnamtannin B1 (CB1) is a condensed tannin with anti-inflammatory and anti-microbial activities. The aims of the study were to evaluate the potential of CB1 as a therapy for rosacea and to characterize the potential mechanisms of action.

Methods

We intraperitoneally administered 20 mg/kg CB1 once daily for 2 days into the LL-37-induced mouse model of rosacea. The effects of CB1 in vivo were evaluated by the observations of lesions, histology, immunohistochemistry, and the transcription and translation of pro-inflammatory cytokines and chemokines. Human keratinocyte HaCaT and monocyte THP-1 were used to characterize the effects of CB1 on LL-37-induced inflammation in vitro. The changes in pro-inflammatory chemokine interleukin-8 (IL-8) were quantitated by enzyme-linked immunosorbent assay (ELISA), and the expressions of genes involved were determined by Western blotting.

Results

CB1 attenuated local redness, inflammation, and neutrophil recruitment in the mouse model of rosacea in vivo. CB1 suppressed myeloperoxidase (MPO) and macrophage inflammatory protein 2 (MIP-2) production, a functional homolog of interleukin-8 (IL-8), at the lesions. In vitro experiments confirmed that CB1 reversed the LL-37-induced IL-8 production in human keratinocytes HaCaT and monocyte THP-1 cells. CB1 inhibited IL-8 production through downregulating the phosphorylation of extracellular signal-regulated kinase (ERK) in the mitogen-activated protein kinase (MAPK) pathway.

Conclusion

CB1 attenuated LL-37-induced inflammation, specifically IL-8 production, through inhibiting the phosphorylation of ERK. CB1 has potential as a treatment for rosacea.
Dnajb8, a target gene of SOX30, is dispensable for male fertility in mice
Authors: Wang Fengsong , Kong Shuai , Hu Xuechun , Li Xin , Xu Bo , Yue Qiuling , Fu Kaiqiang , Ye Lan , Bai Shun
Published: December 2020

Background

The DNAJ family of molecular chaperones maintains protein homeostasis in mitotic and postmeiotic cells, especially germ cells. Recently, we found that the transcription factor SOX30 initiates transcription of Dnajb8 during late meiosis and spermiogenesis in mouse testes.

Methods

We used the CRISPR/Cas9 system to generate Dnajb8 mutant mice and analyze the phenotype of the Dnajb8 mutants.

Results

AlthoughDnajb8 is an evolutionarily conserved gene, it is not essential for spermatogenesis and male fertility. We provide this phenotypic information, which could prevent duplicative work by other groups.
Sevoflurane preconditioning attenuates hypoxia/reoxygenation injury of H9c2 cardiomyocytes by activation of the HIF-1/PDK-1 pathway
Authors: Hou Tianliang , Ma Haiping , Wang Haixia , Chen Chunling , Ye Jianrong , Ahmed Ahmed Mohamed , Zheng Hong
Published: December 2020

Background

Sevoflurane preconditioning (SPC) can provide myocardial protective effects similar to ischemic preconditioning (IPC). However, the underlying molecular mechanism of SPC remains unclear. Studies confirm that hypoxia-inducible factor-1 (HIF-1) can transform cells from aerobic oxidation to anaerobic glycolysis by activating the switch protein pyruvate dehydrogenase kinase-1 (PDK-1), thus providing energy for the normal life activities of cells under hypoxic conditions. The purpose of this study was to investigate whether the cardioprotective effects of SPC are associated with activation of the HIF-1a/PDK-1 signal pathway.

Methods

The H9c2 cardiomyocytes hypoxia/reoxygenation model was established and treated with 2.4% sevoflurane at the end of equilibration. Lactate dehydrogenase (LDH) level, cell viability, cell apoptosis, mitochondrial membrane potential, key enzymes of glycolysis, ATP concentration of glycolysis were assessed after the intervention. Apoptosis related protein(Bcl-2, Bax), HIF-1a protein, and PDK-1 protein were assessed by western blot.

Results

Compared with the H/R group, SPC significantly increased the expression of HIF-1a, PDK-1, and Bcl-2 and reduced the protein expression of Bax, which markedly decreased the apoptosis ratio and Lactate dehydrogenase (LDH) level, increasing the cell viability, content of key enzymes of glycolysis, ATP concentration of glycolysis and stabilizing the mitochondrial membrane potential. However, the cardioprotective effects of SPC were disappeared by treatment with a HIF-1a selective inhibitor.

Conclusion

This study demonstrates that the cardioprotective effects of SPC are associated with the activation of the HIF-1a/PDK-1 signaling pathway. The mechanism may be related to increasing the content of key enzymes and ATP of glycolysis in the early stage of hypoxia.
Effectiveness of the Greater Palatine Nerve Block for Anaesthetising Anterior Palate: A Prospective Study
Authors: Sundar Gopinath Thilak Parepady , Shetty Tripthi Prakash , Bylapudi Bhanuprakash , Shetty Vikram , Castellino Chrysl , Rai Ashish , Karikal Arvind , Shetty Pratiksha
Published: December 2020

Introduction: Local Anaesthesia (LA) is the mainstay of any routine dental extraction. Accomplishing optimum anaesthesia with least pain and anxiety to patients is a challenge. Hence, modification of technique and application of routine dental LA to enhance patient comfort is the need of the hour. In this pursuit, a prospective cohort study was carried out to evaluate the effectiveness of greater palatine nerve block as an alternative to nasopalatine nerve block in anaesthetising the anterior palatal mucosa and to achieve optimum palatal anaesthesia. Aim: The primary outcome variable is to assess the extent of the anaesthetic effect of greater palatine nerve block in maxillary anterior palatal region. Materials and Methods: A total of 100 patients scheduled for the extraction of ipsilateral anterior and posterior maxillary teeth were included in this prospective study between June 2017 to June 2019. Palatal anaesthesia for all the extractions done was achieved only with greater palatine nerve block. After an interval of five minutes, the extent of palatal anaesthesia from the posterior palatal tissue to the anterior region was evaluated for both subjective and objective symptoms. Pain on the palatal mucosa was assessed using Numerical rating scale of 0-10. Post-evaluation, depending on the proposed tooth of extraction, buccal anaesthesia was achieved with Posterior superior alveolar nerve block for posterior teeth and infraorbital nerve block for anterior teeth. Results: Of the 100 patients administered with greater palatine nerve block, it was observed that in 36 patients (36%) had effectiveness in anaesthesia till central incisor, 28 (28%) patients had effectiveness in anaesthesia till lateral incisor, 20 (20%) patients had effective in anaesthesia till the canine and 16 (16%) patients anaesthetic effects were limited to posterior teeth. Overall, 84% had varied degree of positive anterior anaesthesia with greater palatine nerve block alone. Conclusion: Greater palatine nerve block was effective in providing anaesthesia to the posterior region till the premolars, with the extended complete anaesthesia in the anterior region with similar action as the nasopalatine nerve block administered to anaesthetise the anterior palate for extraction of the anterior teeth.
Molecular Mechanism of Oral Submucous Fibrosis induced by Arecoline: A Literature Review
Authors: Cui Lin , Cai Xinjia , Huang Junhui , Li Huiling , Yao Zhigang
Published: December 2020

Oral Submucous Fibrosis (OSMF) is an oral mucosal disease with lamina propria collagen hyperplasia as the main pathological change, which belongs to Oral Potentially Malignant Disorders (OPMDs). Areca nut is identified as a class I carcinogen with complex components. Arecoline is the main component of areca nut which plays an important role in the pathogenesis of OSMF. Through the review of literature, it is shown that arecoline can lead to the change in level of cytokines in oral mucosa, which further leads to the imbalance of collagen metabolism. This article reviews the molecular mechanism research progress of arecoline in promoting the pathogenesis of OSMF in recent years, including Transforming Growth Factor-β (TGF-β) and Reactive Oxygen Species (ROS) associated with increased collagen production, Matrix Metalloproteinase (MMP) and Tissue Inhibitor of Metalloproteinase (TIMP) associated with reduced collagen degradation, hypoxia and microvascular related factors and in order to provide reference for the treatment of the disease at the molecular level.
The Impacts of Fee - Free Education Policy in Junior Secondary Schools in Tanzania
Authors: Lyanga Amani Abisai , Chen Ming-Kun
Published: December 2020

This study was based to examine the impacts of Fee-Free Education Policy in Junior Secondary Schools in Tanzania. The study used secondary data which were collected from the Ministry of Education Science and Technology (MOEST), National Examination Council of Tanzania (NECTA), United Republic of Tanzania (URT), Buchosa District Education Officer (BDEO), and other Non-governmental institutions. Finally, data were analyzed and presented. Data collection was guided by four objects such as the number of classrooms, the number of teachers, the number of students enrolled, and students’ pass rate. The findings from this study demonstrated that a fee-free education policy has shown a direct impact on junior secondary education. Through national examination, the students’ pass rate has improved, also to some extent number of teaches has increased. Apart from that, number of classrooms are imbalance with number of students. Therefore, this study recommended that the Tanzanian government should employ more qualified teachers, at the same time to build more classes to accommodate the number of students.
Characterization of Dry Matter Partition with Grain Yield in Advanced Breeding Lines of Rice (Oryza sativa L.)
Authors: Kumar D. Dev , Reddy D. Vishnu Vardhan , Rao P. Raghuveer , Madhav M. Sheshu , Shankar V. Gouri
Published: December 2020

The experimental field was laid in RBD replicated thrice with 30 high yielding rice genotypes which includes 26 advanced breeding lines (ABL) (SP-351, SP-352, SP-353, SP-354, SP-355, SP-356, SP-357, SP-358, SP-359, SP-360, SP-70, SP-72, SP-63, SP-61, SP-69, SP-55, SP-80, SP-25, SP-13,  SP-03, SP-02, SP-34, SP-37, SP-08, SP-75 and SP-57) and four checks (NDR-359, BPT-5204, IR-64, Jaya). Seven genotypes showed significantly higher leaf weight over the BPT-5204. Further, leaf weight at panicle initiation stage showed a positive relationship with TDM (Total Dry Matter) (r=0.51**). At the panicle initiation stage, only three genotypes (SP-354, SP-358, and SP-72) were superior to BPT-5204 in leaf weight. The shoot biomass and total dry weight was superior only in one genotype SP-72 as compared to BPT-5204. Similarly, the net assimilation rate at panicle initiation stage was maximum in SP-08 (9.92g m-2 day-1) and SP-72 (9.35g m-2 day-1) as compared to check BPT-5204 (6.47g m-2 day-1). These genotypes maintained higher photosynthetic rate (SP-72) and higher grain yield (SP-08). The relationship between CGR (Crop Growth Rate) and TDM (Total Dry Matter) and grain yield (r=0.61**) was positive and significant at physiological maturity. Genotypes SP-08 and SP-72 showed significantly higher CGR (Crop Growth Rate) over BPT-5204 and hence, yielded higher. In the present study compared to BPT-5204, genotypes SP-72, SP-08 maintained higher lea area index at all crop growth stages. These genotypes maintained higher photosynthetic rate (SP-72) and higher grain yield (SP-08). Positive significant relationship between LAI (Leaf Area Index) and total dry matter at harvest and; grain yield has been observed.
Combinatorial Evaluation of Antiviral Activity of some Nigerian Medicinal Plants on SARS-CoV-2Combinatorial Evaluation of Antiviral Activity of some Nigerian Medicinal Plants on SARS-CoV-2
Authors: Falang Kakjing D. , Poyi Catherine O. , Ajima Ukpe , Bukar Bukata B. , Amagon Kennedy I. , Damen James G. , Agabi Yusuf , Kutshik Richard J. , Longdet Ishaya Y. , Gomerep Simji S. , Shittu Ismaila , Davou Stephen D. , Kolawole Jacob A. , Wannang Noel N.
Published: December 2020

The coronavirus disease COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has presented unprecedented challenges to the healthcare systems in the world. There are no definite effective therapeutic agents or vaccines against the virus currently. However clinical management of the infection includes prevention, control measures, supportive care and repurposed drug therapy based on pathophysiology of the virus and manifestation of the disease condition thereby using antiviral agents such as remdesivir, lopinavir and favipiravir. Herbal preparations are being promoted for the management of Covid-19. Some selected Nigerian medicinal plants are hereby investigated by In-silico studies of the plant constituents. When compared with the listed therapeutic agents, the phytochemical constituents of the selected plants have better binding affinity to several Covid-19 viral target proteins. Also they were found to be safe for human use with LD50 of >2000 mg/Kg for the plant extracts. Some of the plants also contained phytochemicals that can be employed for the symptoms of covid-19.
Mechanisms of Diabetic Neuropathies and Antioxidant Therapy
Authors: Alsulaimani Mujahid A. , Magadmi Rania M. , Esmat Ahmed
Published: December 2020

Background: Diabetic neuropathy is very common and affects half of patients with either type 1 or type 2 diabetes mellitus. It is the leading cause of diabetes-related hospital admissions and nontraumatic amputations. Currently, the keys to management are maintaining blood glucose concentration within the normal range and treatment of symptoms. Despite many studies of chronic pain associated with diabetic neuropathy, few improvements have been made.

Main Finding: This is a review of the classification of diabetic neuropathy, molecular mechanisms, and treatment options focusing on antioxidants.

Conclusion: As oxidative stress may play a significant role in the pathophysiology of diabetic neuropathy, the study of molecular mechanisms by which hyperglycemia induces oxidative stress is important. New targets for disease-modifying drugs could be elucidated.
Box-Behnken Design Approach for Optimization of a Liquid Chromatographic Method for the Determination of Anti Leukemic Drugs in Bulk and Pharmaceutical Formulations
Authors: Suresh R. , Swamivelmanickam M. , Sivakrishnan S.
Published: December 2020

To develop and validate a RP-HPLC method for the determination of selected anti- leukemic drugs in bulk and pharmaceutical formulations using Design of experiments. Development of the chromatographic method is based on design of experiments (DOE) approach, utilizing two level full factorial design for screening and Box-Behnken experimental design for optimization. In order to identify the significant parameters for the optimization, by simultaneously registering the main, interaction and quadratic effects of three factors such as volume of methanol (X1), concentration of buffer(X2) and flow rate (X3) on the selected responses like capacity factor K1 of first eluted peak  (Y1), resolution of critical peaks RS (1,2) (Y2) and amp; RS (2,3) (Y3) and retention time of last peak tR4 (Y4) as responses. Analytes were separated on a Onyx monolithic- C18 (100×4.6mm) with mobile phase comprising Potassium dihydrogen orthophosphate (0.01M), Methanol and Acetonitrile in ratio of (30:34.29:35.71), with flow rate of 0.723 mL/min and pH 3.5 adjusted with dilute orthophosphoric acid. Total chromatographic analysis time per samples was approximately 5 minutes with DST(IS), IMT, IBT and SFN eluting with retention times of 2.64, 3.05, 3.81 and 4.59 minutes respectively. Calibration curves were linear over selected range 0.997 for the all analytes. The method was sensitive with the LODs were 10.457, 13.07 and 26.169 ng/mL and LOQs were 31.68, 39.6 and 79.3ng/mL for IMT, IBT and SFN respectively. Inter and Intra-day precision data (in terms of %RSD) was fond to be less than ≥3 respectively, Recoveries ranged ≥102±2% for Imatinib- Gleevec, Ibrutinib- Imbruvica and Sorafenib- Nexavar. The obtained results corroborated the potential of the proposed method for determination of all the three anti-leukemic drugs for routine analysis for products of similar type and composition.
Tetrapleura tetraptera of Ghanaian Origin: Phytochemistry, Antioxidant and Antimicrobial Activity of Extracts of Plant Parts
Authors: Larbie Christopher , Robertson Felix Charles Mills- , Quaicoe Emmanuel Bright , Opoku Rita , Kabiri Naomi Chounbayor , Abrokwah Rachel Owusu
Published: December 2020

Introduction: The role of medicinal plants in meeting the healthcare needs of the populace, particularly in developing countries cannot be overemphasized. They provide holistic treatment and wellbeing due to a plethora of phytochemicals found in them. Among such is Tetrapleura tetraptera (Schum. & Thonn.) Taub., a multipurpose tree plant with varied biological activities. The current study was aimed at assessing the basic phytochemical constituents, free radical scavenging activity as well as the antimicrobial effect on various solvent extracts of leaves, fruit and stem bark of T. tetraptera of Ghanaian origin.

Materials and Methods: Aqueous, 50% hydroethanolic and methanolic extracts were made from the leaves, fruits, and stem bark of T. tetraptera. They were assessed for the qualitative and quantitative phytochemical constituents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, antimicrobial activity as well as the spectroscopic properties (Ultraviolet – visible and Fourier-transform infrared spectroscopy). Compounds in the methanolic extracts were evaluated using the gas chromatography–mass spectrometry.

Results: Tannins, reducing sugars, coumarins and flavonoids were present in all extracts while hydroethanolic and methanolic extracts were rich in phenols, tannins and flavonoids, especially for the stem bark. Leaf extracts had better antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans and Proteus mirabilis.

Conclusion: Generally, leaves and stem bark extracts of T. tetraptera are rich in biologically active phytochemicals, supporting their use in ethnomedicine and could be exploited further for other biological activities.