bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of surface structures and functionalities in perovskite-type ferroelectric oxides and their potential applications
Authors: Pei Ming-Hui , Tian Yu , Zhang Jin-Xing ,   Department of Physics, Beijing Normal University, Beijing 100875, China,   School of Basic Medical Sciences, Air Force Medical University, Xi’an 710032, China
Published: December 2020

Over the past decades, exploration and artificial control of the surface and interfacial structure of the materials have played an important role in chemical catalyzing, energy conversion, information storage and medical field, and thus the finding of suitable materials with controllable surface/interface properties has attracted intense interest in recent years. Perovskite-type ferroelectric oxides are considered to be one of the most promising functional materials due to their intrinsic, non-volatile, reversible spontaneous polarization and controllable polar surface with high charge density. The investigating of the interaction between polarization and surface structure of perovskite-type ferroelectric oxide is very important for understanding the surface (interface) energy conversion, regulating the adsorption and desorption on the surface, controlling interfacial chemical reaction, and designing stable low-power electronic devices. In this paper, we summarize the theoretical mechanism and potential applications of the surface structures and functionality in perovskite-type ferroelectric oxide from three aspects. Firstly, we describe the inseparable relationship between the stabilized ferroelectric phase and surface structure of ferroelectric material, and illustrate the formation mechanism of complex surface structure of perovskite-type ferroelectric oxide. In order to reduce the surface energy to stabilize the polar surface of the material, perovskite-type ferroelectric oxide always needs to absorb foreign charged particles, change the stoichiometry and conduct electron orbital hybridization or surface relaxation, etc., which will cause the complexity of the surface structure of ferroelectric. Secondly, we outline the influence of ferroelectric polarization on the surface structure of ferroelectric and the behavior of changing ferroelectric polarization by controlling surface structure through adjusting the external environment, which provides an important basis for the subsequent regulation of the surface performance and functionality of perovskite-type ferroelectric oxide. Finally, we introduce the utilization of the controllable physical and chemical properties of ferroelectric surface (interface) into large area and into nanoscale (nanodomain), which has bright application prospects in many frontier fields, including non-volatile memory system, cell proliferation, microfluidic control system, catalysis, optical device and photodetector and so on. Furthermore, considering the limitations of current scientific research about the ferroelectric surface, we put forward the prospects for the future development of the ferroelectric material in the areas of information storage, controllable chemical reactions and new energy conversion.
Terahertz coding metasurface based vanadium dioxide
Authors: Li Jia-Hui , Zhang Ya-Ting , Li Ji-Ning , Li Jie , Li Ji-Tao , Zheng Cheng-Long , Yang Yue , Huang Jin , Ma Zhen-Zhen , Ma Cheng-Qi , Hao Xuan-Ruo , Yao Jian-Quan ,   The Institute of Laser and Opto-electronics, School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China,   Key Laboratory of the Ministry of Education on Optoelectronic Information Technology, Tianjin University, Tianjin 300072, China
Published: December 2020

Terahertz (THz) has the characteristics of non ionization, penetration, water absorption, high resolution, etc. It has shown an important application prospect in many fields, such as non-destructive testing, imaging and communication. However, THz is in the transition frequency band ranges from macro-electronics to micro-photonics, so, it belongs to the interdisciplinary field, forming the “terahertz gap” in electromagnetic wave. In recent years, with the continuous development and improvement of THz radiation source and detection technology, the THz modulation technology has gradually aroused the interest of researchers. Metamaterials with many properties that natural materials do not possess provide a common way to control THz. The two-dimensional structure of a metamaterial is called a metasurface. The coding metasurface encodes the phase digitally so that the electromagnetic wave can be regulated. It is proposed that it is first in the microwave band and then extended to the THz band. In the microwave band, the number, direction and amplitude of the far-field beams can be changed dynamically by programming, which is connected with the integrated circuit such as FPGA by using diodes, but due to the limitation of diode size and micro-nano manufacturing technology, the programmable metasurface in microwave band cannot be well used in THz band. In order to improve the flexibility of THz coding metasurface, in this paper we choose the phase change material vanadium dioxide (VO2) to active modulation coding metasurface. In this paper, we analyze the VO2’s insulating state before the phase transformation and metallic state after the phase transformation. Then designing an active control 1 bit coding metasurface by using the influence of the two states on the amplitude and phase of the unit structure, which is composed of VO2, polyimide and aluminum, can not only realize the basic function of coding metasurface adjusting the electromagnetic wave beams, but alsoimplement the switching of two kinds of far-field beams at 1.1 THz for the same coding sequence by thermal stimulated VO2. The coding metasurface also realizes the switching between two near-field focal points at 1.1 THz for the same coding sequence. Based on the effect of VO2 on the phase, this coding metasurface provides a new way to adjust and control the THz wave flexibly, and will have a great application prospect in THz transmission, imaging and communication.
Digital line scanning fluorescence microscopy based on digital micromirror device
Authors: Wang Mei-Chang , Yu Bin , Zhang Wei , Lin Dan-Ying , Qu Jun-Le ,   Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
Published: December 2020

Laser scanning confocal microscope (LSCM) is one of the most important tools for biological imaging due to its strong optical sectioning capability, high signal-to-noise ratio, and high resolution. On the basis of LSCM, line-scanning fluorescence microscopy (LSFM) uses linear scanning instead of point scanning to improve the speed of image acquisition. It has the advantages of simple system structure, fast imaging speed, and weak phototoxicity, and in addition, it is more suitable for high-resolution and fast imaging of living thick samples. It is of great significance for studying the life science, biomedicine, and others. However, the current LSFM technology still faces many urgent problems in terms of system flexibility, imaging speed, resolution and optical sectioning capabilities. Therefore, based on the existing multifocal structured illumination microscopy (MSIM) in our laboratory, a digital line-scanning fluorescence microscopy (DLSFM) based on digital micromirror device(DMD) is presented in this paper. In the illumination path, a high-speed spatial light modulator DMD is adopted to realize multi-line parallel scanning excitation, which simplies the optical system and improves the flexibility and scanning speed of the system. A DLSFM image reconstruction algorithm based on the standard deviation of fluorescence signal is proposed, which is combined withthree-dimensional (3D) Landweber deconvolution algorithm to achieve 3D high-resolution optical slice image reconstruction. On this basis, the imaging experiments on fluorescent beads and standard samples of mouse kidney section are carried out by using DLSFM. The experimental results show that the resolution of DLSFM in the x, y and z directions is 1.33 times, 1.42 times and 1.19 times that of wide field microscope, respectively, and the fast 3D high-resolution optical sectioning imaging of biological samples is realized, which lays a technical foundation for further developing the rapid high-resolution imaging of the whole cells and tissues in vivo.
Temperature measurement in combustion flow field with femtosecond laser-induced filament
Authors: Li Shuai-Yao , Zhang Da-Yuan , Gao Qiang , Li Bo , He Yong , Wang Zhi-Hua ,   State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China,   State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
Published: December 2020

Laser-based diagnostic techniques are critical nonintrusive methods of measuring the in-situ temperature in combustion flow fields. Developing temperature measurement techniques with high accuracy and precision is of great significance for studying the combustion. At present, nanosecond (ns) lasers are commonly used in these methods. However, the researches based on femtosecond (fs) lasers are relatively few. Here, we develop a thermometry technique for combustion fields based on fs laser-induced filament. When the fs laser propagates in an optical medium, a long uniformly distributed plasma channel (also named filament) will be generated. The clamped intensity inside the filament is high enough to generate excited atoms/molecules through fs laser-induced photochemical reactions. Subsequently, the excited atoms/molecules release fluorescence signals. The length of the filament can be measured by imaging the fluorescence signal with an ICCD camera, which is evaluated by the full width at half maximum (FWHM) of the spatial distribution of the filament emission signal. Based on theoretical analysis, the experimental data of the filament length are fitted with a power function, and the result is satisfactory compared with the R-squared measure of goodness (R2) of 0.984. This indicates that the filament length is correlated well with the temperature of the combustion field. A monotonic quantitative relationship between the filament length and the temperature can be established by a calibration process, and then the temperature of the combustion field can be measured. When the temperature changes from 1630 to 2007 K, the length of the filament shortens by 38%. This indicates that the filament length is sensitive to the temperature of the flow field. When the temperature is 2007 K, the absolute uncertainty of the measurement is ±25 K, and the relative uncertainly is about 1.2%. The spatial resolution of the measurement system is 50 μm, which was determined by a USAF 1951 Target. Based on the spatial resolution, the measurement precision can arrive at 17 K. Although, at present, this temperature measurement technique based on femtosecond laser-induced filament is used only in laminar premixed flames, it has potential applications in temperature measurements ranging from room temperature to combustion temperatures.
Research progress of self-powered flexible biomedical sensors
Authors: Tan Pu-Chuan , Zhao Chao-Chao , Fan Yu-Bo , Li Zhou ,   School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China,   Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100083, China,   Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China,   Department of Biomedical Engineering, School of Medical Engineering, Foshan University, Foshan 528000, China
Published: December 2020

In recent years, flexible biomedical sensors have received extensive attention and achieved great development. However, the battery life of flexible biomedical sensors is limited, which has become a bottleneck restricting the development of flexible biomedical sensors. The concept of self-powered flexible biomedical sensor provides an important idea for solving battery life problem. This review summarizes the research progress of self-powered flexible biomedical sensors over the years. Besides, this review discusses several self-powered flexible biomedical sensors based on different power generation technologies and different materials, as well as their respective advantages and scope of application. Further, some representative research works are selected and discussed in detail. Self-powered flexible biomedical sensors can be divided into wearable self-powered flexible biomedical sensors and implantable self-powered flexible biomedical sensors according to their working positions, which can be used to collect important physiological indicators such as human respiration, pulse, temperature, etc. Finally, this paper also predicts and evaluates the future research direction of self-powered flexible biomedical sensors.
A tabletop experimental system for investigating ultrafast atomic dynamics based on femtosecond extreme ultraviolet photons
Authors: Hai Bang , Zhang Shao-Feng , Zhang Min , Dong Da-Pu , Lei Jian-Ting , Zhao Dong-Mei , Ma Xin-Wen ,   Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China,   University of Chinese Academy of Sciences, Beijing 100049, China,   School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
Published: December 2020

Femtosecond extreme ultraviolet (XUV) light pulses play an important role in investigating the ultrafast dynamics of atoms and molecules, and are complementary to the conventional large facilities like synchrotron radiation and free electron laser. We build a table-top femtosecond extreme ultraviolet light source based on the high-order harmonic generation (HHG) process of gaseous medium in a strong laser field. We implement HHG by focusing an intense IR laser into a 5 cm long gas-filled hollow waveguide, instead of the conventional tightly focusing geometry with gas jet. Inside the waveguide, the laser peak intensity is nearly constant and the gas pressure is well-controlled, making it possible to maintain the phase matching condition over an extended distance. And a fully coherent high harmonic beam builds up along the waveguide, leading to a dramatically higher HHG efficiency. Monochromatic XUV light pulses are obtained by spectral selection of the HHG through employing the conical diffraction method of grating. With this geometry used, the pulse broadening caused by wave front tilting during the diffraction can be strongly suppressed, especially for the case of grazing incidence. And the femtosecond temporal character of the light pulse can be preserved while keeping a high reflectivity. The temporal broadening of the XUV light pulse in our setup is estimated to be within 100 femtosecond. By using different noble gases, photons with energy values ranging from 20 eV to 90 eV are produced. For the 27th-order harmonic centered at 41.9 eV, the flux is measured to be 1 × 1010 photons per second, with an energy spread of 0.4 eV. In order to investigate the ultrafast dynamic behaviors of gaseous atoms and molecules with an HHG-based XUV source, we develop a reaction microscope with ultrahigh vacuum of about 10–11 mbar. The combination of HHG-based XUV with the newly developed reaction microscope provides a unique tool for studying the XUV photon and atom/molecule interaction. A series of experiments has been successfully carried out on the platform and the system shows good performance.
Enhancement of Faraday rotation of black phosphorus by extraordinary optical transmission of the metal grating
Authors: Dong Da-Xing , Liu You-Wen , Fu Yang-Yang , Fei Yue ,   Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Published: December 2020

Black phosphorus(BP) is a kind of two-dimensional (2D) material with direct bandgap. Its adjustable bandgap fills the gap between graphene and transition metal dichalcogenides(TMDCs). At the same time, the black phosphorusalso has a higher charge carrier mobility. The unique fold-like crystal structure of the black phosphorus leads to in-plane anisotropy and it makes the photoelectric response anisotropic. It shows that the properties of black phosphorus can be dynamically adjusted by various methods. These characteristics make black phosphorus a two-dimensional material with great potential applications in the visible light to mid-infrared region and even terahertz bands. In view of this, this paper focuses on the magneto-optical response of black phosphorus. In this paper, we design a magneto-optical device in Au grating/black phosphorus/silicon hybrid plasmonic structures. The inducing of abnormal transmission through the metal grating significantly enhances the transmittance, while the Faraday rotation effect is enhanced through the mode coupling between the TE and TM in the THz range. The rigorous coupled wave analysis (RCWA) is used to calculate the transmittance of the grating. The finite element software COMSOL Multiphysics is used to calculate the transmittance and simulate the electric field distribution of the magneto-optical device. Under the optimal parameters, the Faraday rotation can increase 14.434 times, reaching to 2.7426°, and the transmittance is more than 85% with an external magnetic field of 5 T at the operation frequency (1.5 THz). We plot the electric profiles of the magneto-optical device with and without BP to prove that the Faraday rotation is a result of the magneto-optical property of the monolayer phosphorus and that the enhancement is due to the mode coupling between the TE and TM. Moreover, we extract the tunable character of the magneto-optical device with the external magnetic field and the carrier density of the black phosphorus. The external magnetic field can effectively tune the Faraday rotation angle while keeping the working wavelength and the transmittance substantially unchanged. The increasing of the carrier density will not improve the Faraday rotation angle, for the changes in surface conductivity under fixed structural parameters will disrupt the mode coupling. At the same time the transmittance will decrease, because the larger carrier density will enhance the absorption of the BP. Therefore, to obtain a higher FR angle with apparent transmittance, the carrier density should not be too high. Finally, the effects of the spoof surface plasmons on the waveguide mode and the Faraday magneto-optical effect are also discussed.
The effects of the recombinant YeaZ of Vibrio harveyi on the resuscitation and growth of soil bacteria in extreme soil environment
Authors: Li Yanlin , Chen Jixiang , Wang Yonggang , Ma Dan , Rui Wenhong
Published: December 2020

Numerous bacteria entered the viable but non-culturable state due to the stresses of dry and salt in soils. YeaZ of Gram-negative bacteria is a resuscitation promoting factor (Rpf) homologous protein could resuscitate bacteria of natural environment in VBNC state. To investigate the promoting effect of YeaZ on the isolation of viable but non-culturable (VBNC) bacteria from soil samples in extreme environments, the recombinant YeaZ of Vibrio harveyi was prepared and added to the soil samples from volcanic soil and saline soil in Northwest China. The study has shown that YeaZ can promote the recovery and growth of soil microorganisms, and the number of cultivable bacteria in volcanic and saline soil has increased from 0.17 × 103 and 2.03 × 103 cfu⋅ml−1 to 1.00 × 103 and 5.55 × 103 cfu⋅ml−1, respectively. The 16S rDNA gene sequencing and phylogenetic analysis showed that YeaZ played an essential role in the increase of composition and diversity of bacteria. A total of 13 bacterial strains were isolated from the volcanic soil samples, which belong to phyla Actinobacteria, Firmicutes and Gamma-proteobacteria. Four species, including Ornithinimicrobium kibberense, Agrococcus citreus, Stenotrophomonas rhizophila and Pseudomonas zhaodongensis were found in the control group, while Micrococcus antarcticus, Kocuria rose, Salinibacterium xinjiangense, Planococcus antarcticus, Ornithinimicrobium kibberense and Pseudomonas zhaodongensis were isolated from the treatment groups (addition of YeaZ). Twenty-one strains were isolated from the saline soil samples, including eight species from the control group and thirteen species from the treatment groups, among which nine species were only found, including Bacillus oceanisediminis, Brevibacillus brevis, Paenibacillus xylanilyticus, Microbacterium maritypicum, B. subtilis, B. alcalophilus, B. niabensis, Oceanimonas doudoroffii and Zobellella taiwanensis. The results suggest that addition of YeaZ to soil samples can promote the recovery of VBNC. This method has the implications for the discovery of VBNC bacteria that have potential environmental functions.
Estimating salt content of vegetated soil at different depths with Sentinel-2 data
Authors: Chen Yinwen , Qiu Yuanlin , Zhang Zhitao , Zhang Junrui , Chen Ce , Han Jia , Liu Dan
Published: December 2020

The accurate and timely monitoring of the soil salt content (SSC) at different depths is the prerequisite for the solution to salinization in the arid and semiarid areas. Sentinel-2 has demonstrated significant superiority in SSC inversion for its higher temporal, spatial and spectral resolution, but previous research on SSC inversion with Sentinel-2 mainly focused on the unvegetated surface soil. Based on Sentinel-2 data, this study aimed to build four machine learning models at five depths (0∼20 cm, 20∼40 cm, 40∼60 cm, 0∼40 cm, and 0∼60 cm) in the vegetated area, and evaluate the sensitivity of Sentinel-2 to SSC at different depths and the inversion capability of the models. Firstly, 117 soil samples were collected from Jiefangzha Irrigation Area (JIA) in Hetao Irrigation District (HID), Inner Mongolia, China during August, 2019. Then a set of independent variables (IVs, including 12 bands and 32 spectral indices) were obtained based on the Sentinel-2 data (released by the European Space Agency), and the full subset selection was used to select the optimal combination of IVs at five depths. Finally, four machine learning algorithms, back propagation neural network (BPNN), support vector machine (SVM), extreme learning machine (ELM) and random forest (RF), were used to build inversion models at each depth. The model performance was assessed using adjusted coefficient of determination (R2adj), root mean square error (RMSE) and mean absolute error (MAE). The results indicated that 20∼40 cm was the optimal depth for SSC inversion. All the models at this depth demonstrated a good fitting (R2adj≈ 0.6) and a good control of the inversion errors (RMSE < 0.16%, MAE < 0.12%). At the depths of 40∼60 cm and 0∼20 cm the inversion performance showed a slight and a great decrease respectively. The sensitivity of Sentinel-2 to SSC at different depths was as follows: 20∼40 cm > 40∼60 cm > 0∼40 cm > 0∼60 cm > 0∼20 cm. All four machine learning models demonstrated good inversion performance (R2adj > 0.46). RF was the best model with high fitting and inversion accuracy. Its R2adj at five depths were between 0.5 to 0.68. The SSC inversion capabilities of all the four models were as follows: RF model > ELM model > SVM model > BPNN model. This study can provide a reference for soil salinization monitoring in large vegetated area.
Surface Hardness of Nanohybrid and Microhybrid Resin Composites Cured by Light Emitting Diode and Quartz Tungsten Halogen Light Curing Systems: An Invitro Study
Authors: Wankhade Anuradha Vitthal , Kamat Sharad Basavraj , Hugar Santosh Irappa , Nanjannawar Girish Shankar , Vhate Sumit Balasaheb
Published: December 2020

Introduction: New generation composite resin materials have revolutionized the art of aesthetic dentistry. The clinical success is dependent on effective polymerisation and surface hardness which in turn are dependent on the performance of Light Curing Units (LCU). This study utilises surface hardness as a measure of degree of polymerisation of composite resins achieved by LCUs. Aim: To evaluate the difference in surface hardness of nanohybrid and microhybrid resin composites cured by light curing systems, Light Emitting Diode (LED) and Quartz Tungsten Halogen (QTH). Materials and Methods: In this invitro experimental study, two types of hybrid composites (Nanohybrid and Microhybrid) were tested for surface hardness by using two different light curing systems (LED and QTH). All the Nanohybrid and Microhybrid specimens were cured using LED and QTH LCUs, thus giving four combinations. A total of 60 specimens (6 mm diameter and 2 mm depth) were prepared using Teflon mould with 15 samples for each combination. Surface hardness was measured on upper and lower surface after 24 hours and hardness ratio was calculated. Data was analysed using independent t-test for intergroup comparison. Level of significance was kept at 5%. Results: Surface hardness of resin composites cured by LED LCU was greater than those cured by QTH LCU. Additionally, the hardness value was greater for the upper surface. Nanohybrids showed better surface hardness than Microhybrids for both the LCUs. Conclusion: Nanohybrid composite resins and LED system were found to be more effective in terms of surface hardness as compared to their counterparts.
Association between Blood Pressure and Obesity Indices in Medical Students
Authors: Gandhi Shalini , Sorout Jitender , Raina Rohit , Raina Abhay , Miglani Urvashi , Manchanda Kailash , Reddy Satyanath
Published: December 2020

Introduction: Obesity is strongly associated with other metabolic disorders including Hypertension (HTN), diabetes and Cardiovascular Diseases (CVD). High Blood Pressure (BP) is ranked as the third most important risk factor for attributable burden of disease in South Asia. Aim: The aim of present was to study the association between BP and obesity indices in medical student’s population. Materials and Methods: A cross sectional study was conducted on a group of 100 healthy young medical students. BP, pulse and Hb O2% was measured by using sphygmomanometer, pulse oximeter. Obesity indices were measured by using weighing machine, stadiometer, measuring tape and impedance based Body Composition Analyser (BCA). Results: There was poor correlation of Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) with Total Body Fat (TF) and the association was not significant. SBP and DBP were mildly correlated with BMI. Whole body Visceral Fat (VF) correlation of SBP was moderate and significant. DBP was correlated with whole body VF and correlation was significant. But the whole body, trunk, leg Skin Fat (SF) and Muscle Fat (MF) were not having significant correlation with SBP and DBP. Finger to heart distance was positively correlated with SBP (p<0.05). Also, O2%, chest and hip size were positively correlated with SBP (p<0.05). Only whole body VF and Waist Hip Ratio (WHR) were significantly (p<0.05) affected SBP. None of the other parameters affected DBP. Conclusion: The present study results found that Body Mass Index (BMI), VF and WHR had significant correlation with systolic and SBP and DBP. VF and WHR were significant predictors of SBP.
The Professional Satisfaction of Tunisian Secondary School Teachers after the Deconfinement of the COVID-19 Epidemic
Authors: Hawani Aymen , Chikha Anis Ben
Published: December 2020

In Tunisia, as in the rest of the world, the Covid-19 crisis has forced the authorities to suspend classes. More than 2 million pupils and 90 thousand of teachers have been deprived of school. After three months of confinement, authorities say the school year is over except for baccalaureate candidates. Indeed, the resumption of courses for final classes (bac) is set for May 27, 2020. The question of the professional satisfaction of Tunisian secondary school teachers after the DE confinement of the COVID 19 epidemic for teachers during the period of DE confinement seems essential. The objective of this article is to highlight the degree of professional satisfaction perceived by secondary education teachers in the governorate of 'Nabeul' in different subjects (Mathematics, Physics, SVT, French, English ...) in the presence of the stress and anxiety caused by the current situation of the emergence of the COVID-19 epidemic and in the presence of the health protocol in schools. (1) Background: Personal satisfaction linked to the professional context was measured using the Austrian questionnaire "Qualität in Schulen", translated into French by the Luxembourg Ministry of Education. (2) Methods: after 3 weeks of resuming the course, during the period from 06/22/2020 to 06/27/2020 Three hundred and sixty (n = 360) questionnaires were sent and two hundred and forty-six (n = 246) questionnaires for processing, hence the return rate is 68.33%, which can be considered satisfactory. (3) Results : secondary teachers demonstrated a high degree of satisfaction at the relational level (students, administrative bodies, colleagues, etc.). Whereas, the teaching aids presented to schools during this period were not satisfactory despite the establishments' desire to remain operational during this period of the resumption of classes. (4) Conclusion: These preliminary results elucidate that the resumption of classes in Tunisia for the final classes (baccalaureate) after a period of confinement due to the emergence of the COVID-19; made it possible to create a specific climate in the high school. Consequently, the teachers showed a high degree of satisfaction at the relational level while they were not satisfied with the level of the didactic means presented to the breasts of the high school.
Market Orientation of KVK Adopter Farmers: The Socio-Ecological and Managerial Interpretation
Authors: Mahato Mrityunjoy , Ghosh Arindam , Acharya S. K. , Ghoshal Swagata , Mazumder Debashis , Haque Monirul , Biswas Amitava
Published: December 2020

Krishi Vigyan Kendra was established initially to impart training to the different stake holder of the farming community as a method of technology delivery system. As the time passed by this grass root institution has undergone a tremendous change, starting from technology generation, testing, verification and ultimately onwards transmission to the end users for the enhancement of the productivity in particular and for the overall socio- economic development of the rural people in general with its mandated programmes.  The work was conducted with 10 independent variables and one dependent variable-.i.e. Market orientation (y). Purposive as well as simple random techniques were adopted for the study. Among 50 adopted KVK farmers of the selected villages only 22 adopted farmers have been randomly selected and more 22 non adopted farmers and thus altogether 44 farmers have been randomly selected for the study. It is found from the results that cropping intensity plays an important role on market orientation. Cropping intensity determines the cultivated area which contributes to the income and forest coverage of a family on their daily Market orientation. So, far as the management dimension is concern, human resource development through training, planning orientation, market orientation has got tremendous impact almost in every sphere of KVK activities.
Gender Based Comparison of Nutrition Status among Primary School Children in Selected Urban and Rural Areas in Ondo State, Nigeria
Authors: Akindele Onetufo Kolawole , Obaghwarhievwo Adjene Josiah
Published: December 2020

In today’s Nigeria, widespread and severe poverty is a reality that depicts a lack of food, clothes, education and other basic amenities and basically affects women and children. This study compared and contrasts gender-based nutritional status in primary school children of selected rural and urban settlements in Ondo State, South-West Nigeria. Using the Multi-staged sampling technique, two hundred and forty (240) primary school students of between the ages of 5 and 10 years were ethically recruited from aforementioned area. Socio-demographic data was collected by way of interview, using a research administered questionnaire that contained both open and closed ended questions. Secondary information was also sourced from the ministry of health, internet, published research papers, journals and other relevant sources. Here, dependent variables consisted of the nutritional status of children in study area(s) that were measured through various nutrition indicators as; height-for-age, weight-for-height, weight-for-age. These indicators were measured through anthropometric techniques, as well as gender specific variations in target variables. Results were sorted, analysed and presented in percentage (using the statistical package for social sciences, SPSS) were used for quantitative data integration on socio-economic and demographics. From the result, most (60.0%) of the respondents’ parents in the urban are within the age range of 31-40 years while most (44.0%) in the rural were within the age range of 21-30 years. In all, none of the urban parents were within the age range of 15-20 years while 10.0% of the rural parents were within the age range of 15-21 years. The mean age of urban parents was 34 years while the mean age of rural parents was 31 years. It can be deduced from the results that rural parents involved were higher than their urban counterparts. Mean consumption pattern of carbohydrates by urban respondents was higher than that of the rural counterparts, lower for proteins consumption pattern as well as in vitamins, even though nutritional status proved otherwise for urban against rural children. Nutritional enlightenment programmes is recommended for parents of rural settled children in order keep abreast of the importance of healthy eating. Further study aimed at corroborating these findings should also be carried out.
Resource Development and Market Value for Non-wood Forest Products of the Banyang-Mbo Sanctuary of Nguti, Cameroon
Authors: Buh Tem Henry , Samuel Tchatat Kezeta Bili
Published: December 2020

The research begins with a brief history of the Banyang-Mbo Sanctuary (BMS) of Nguti, its demographic and geographic dispersion. Next, we aim to identify and analyze the various non-timber forest products, which range from plants, animals, birds and marine species.

With the aid of write-ups from the Wildlife Conservation Society (WCS) Cameroon, the spatial distribution of these products, vis-à-vis their proximity to surrounded villages is presented. Effort is equally made to know the activities of the villages and other environmental factors that affect the growth and existence of these products. Three objectives and three hypotheses were formulated to give direction to the study. Convenient and purposive sampling techniques were used in the study with the help of questionnaires for data gathering. The population of the study comprised 141 households in Nguti vicinity and a sample size of 105 respondents obtained with the use of Yaro Yamen’s formula. The statistical tools used for data analysis were frequency, mean and tables of percentages to organize the data collected. The instrument was validated by three experts and reliability justified by a coefficient. The study recommended that education on the development of non-wood forest resources should be practically oriented and existing markets should be sustained while new ones be sought for the sales of the final products.
Cashless Society: The Effect of Financial Ability, Ease and Security on Behavior of the Use of Financial Technology System
Authors: Kamil Islamiah
Published: December 2020

This study aims to examine the factors that influence the system using Financial Technology (Fintech) by using multiple linear regression. This research was conducted in the Jakarta, Bogor, Depok, Tangerang and Bekasi areas using survey methods. This study obtained 200 respondents who had used Cashless Payment (Example: GO-PAY, GRAB-PAY, FUNDS, LINKS, TAPCASH, OVO, T-Cash, etc.). Researchers used SPSS 22 software to test research data. The results of the analysis for this model show that Financial Capability, Ease and Safety have a positive and significant effect on the Use of Financial Technology (Fintech) System.
Phytochemical Screening and Anti-inflammatory Properties of Henna Leaves (Lawsonia inermis)
Authors: Chuku L. C. , Chinaka N. C. , Damilola Dada
Published: December 2020

In traditional West African setting, plants are commonly used for cosmetic and medicinal benefits such as antibacterial, antifungal, anti-inflammatory, antioxidant and antiparasitic effect of which Henna (Lawsonia inermis), a natural occurring plant of the lythraceae family is not an exception. A preliminary qualitative phytochemical screening and anti-inflammatory properties of Lawsonia inermis leaves extracted with N-butanol and ethyl acetate was investigated. Standard analytical procedures were observed, and statistical analysis using ANOVA version 20.0 was conducted to analyze for mean ± standard deviation (SD) and the least significant difference (LSD) obtained from the study. Results revealed the presence of flavonoids, tannins, terpenes, cyanogenic and cardiac glycosides; while In vivo anti-inflammatory activity wasobserved on a week old cockerel chicks induced carrageenan inflammation post extract administration, using aspirin tablet as control. The anti-inflammatory activity of the extract as portrayed could be attributed to the plants rich phytochemical potential.
Preparation, Characterization and Utilization of Coconut Adsorbents as a Filter Media for Wastewater Treatment
Authors: Kaviya S. , Jayabalakrishnan R. M. , Maheswari M. , Selvakumar S.
Published: December 2020

The present study investigates the characterization of different coconut based low cost adsorbents like coconut shell biochar, zinc chloride impregnated coconut shell activated carbon, coir fibre and coir geotextile and their suitability characteristics as a filter bed in different wastewater treatment process. The characterization study helps to investigate their physical, chemical and morphological properties like proximate and ultimate analysis, iodine number, decolorizing power, SEM, Surface area using BET, Particle size and Zeta potential. The experiment results showed that among the different adsorbents activated carbon has high fixed carbon content (82.99 percent), more surface area (590.8 m2 g-1), low ash content (1.31 percent) with a decolorizing power of 240-300 mg g-1. The coir fibre and coir geotextile having neutral pH with negative surface charge easily adsorbs the positive cations from aqueous solutions at highest apparent density. The experimental findings suggest that the activated adsorbent which shows better results as an effective filter media for adsorption of organic compounds and pollutants from wastewater.
The Uniqueness of Stationary Solution for Nonlinear Random Reaction-diffusion Equation
Authors: Hoxha Sofije , Kolaneci Fejzi
Published: December 2020

We study a nonlinear random reaction-diffusion problem in abstract Banach spaces, driven by a real noise, with random diffusion coefficient and random initial condition. We consider a polynomial non linear term. The reaction-diffusion equation belongs to the class of parabolic stochastic partial differential equations. We assume that the initial condition is an element of Hilbert space. The real noise is a Wiener process. We construct a suitable stochastic basis and define the solution of reaction-diffusion problem in the weak sense. We define the stationary process in abstract Banach spaces in the strong sense of Doob-Rozanov. That is, the probability density function of the stochastic process is independent of time shift. We define the invariant measure for random reaction-diffusion equation in the sense of Arnold, DaPrato, and Zabczyk [1,2]. In other words, we define the invariant measure for random dynamical system, associated with random reaction-diffusion problem.

Using the Variation Inequalities Theory, we prove the uniqueness of stationary solution for nonlinear random reaction-diffusion problem. The obtained theoretical results have several applications in Quantum Physics, Biology, Medicine, and Economic Sciences. Especially, we can study the existence of stationary solution for the stochastic models of tumor growth.
Cost-benefit Analysis of Different Agroforestry Systems and Practices of Kaharole Upazila of Dinajpur District, Bangladesh
Authors: Rahman M. S. , Roy P. R. , Ali M. M. , Bari M. S. , Sarmin I. J. , Rahman M. A.
Published: December 2020

A study was carried out to evaluate the costs and benefits of three agroforestry systems like homestead, cropland and orchard agroforestry of Kaharole Upazila under Dinajpur district of Bangladesh. An extensive field survey and measurements were conducted during July 2017 to January 2018 at different unions and villages of Kaharole upazila. A multistage random sampling procedure was followed in this study to select the survey area. A pre-structured questionnaire was used for collecting the benefits and costs data. A total of 60 agroforestry practices including 20 homesteads, 20 orchards and 20 croplands were evaluated for cost and benefit analysis. Initial three years costs and income data were collected from the field survey. A projection of seven years cost and income was also produced using regression model. Results of the production cost analysis showed that significantly maximum production cost was in orchard agroforestry system (Tk. 98987 per ha.) followed by cropland (Tk. 90238 per ha.) and minimum in homestead system (Tk. 10854 per ha.) in the 1st year. But production cost decreasing trend was recorded in the successive years in all the systems. In case of gross income analysis showed that though initial income was significantly lower in orchard agroforestry followed by cropland and homestead but after tenth year higher income was found in orchard agroforestry system (Tk. 564758 per ha.) followed by cropland (Tk. 251914 per ha) and homestead (Tk.234234 per ha) agroforestry system. However, the net income indicated that orchard agroforestry system was financially more profitable than cropland and homestead agroforestry systems, but the benefit-cost ratio (BCR) was higher in homestead as well as cropland agroforestry systems and lower in orchard agroforestry system. On the other hand guava based agroforestry practice was more lucrative than all other practices. In spite of higher BCR of homestead agroforestry, farmers in the study area widely practiced the orchard agroforestry. It appears that the farmers’ decision regarding what kind of land use they will adopt depends not on the BCR, but largely on the net amount of income that they earn.
Kinetics of the electrogenic step and cytochrome b6 and f redox changes in chloroplasts
Authors: Selak M.A. , Whitmarsh J.
Published: July 2002

The spectroscopic measurements of the slow phase of the electrochromic effect and the redox kinetics of cytochrome b
6 and f provide strong evidence that a Q cycle operates in chloroplasts under conditions of non‐cyclic electron transport. The effect of HQNO and DBMIB on the extent and kinetics of these light‐induced changes places several constraints on the mechanism of quinol oxidation by the cyt. b/f—FeS complex: for each electron removed from the cyt. b/f—FeS complex by P700 an additional charge is transferred across the membrane; the cyclic pathway of electrons involved in quinol oxidation by the cyt. b/f—FeS complex includes at least one of the two b6 cytochromes; the electrogenic step associated with quinol oxidation is subsequent to the reduction of at least one cytochrome b6 quinol oxidation may proceed in a stepwise manner, with the first electron going to cytochrome b6 and the second electron going to the FeS center and cytochrome f.
Kinetics of the oxidation—reduction reactions of the photosystem II quinone acceptor complex, and the pathway for deactivation
Authors: Robinson Howard H. , Crofts Antony R.
Published: July 2002

When the photosystem II quinone acceptor complex has been singly reduced to the state QAQ−
B, there is a 22 s half‐time back‐reaction of Q−
B with an oxidized photosystem II donor (S2), directly measured here for the first time. From the back‐reaction kinetics with and without inhibitors, kinetic and equilibrium parameters have been estimated. We suggest that the state QAQ−
B of the complex is formed by a second‐order reaction of vacant reaction centers in the state Q−
A with plastoquinone from the pool, and discuss the physico‐chemical parameters involved.
Isolation of oxygen‐evolving phycobilisome—photosystem II particles from Porphyridium cruentum
Authors: Clement-Metral Jenny D. , Gantt Elisabeth
Published: July 2002

Photosystem II phycobilisome particles were isolated from the red alga Porphyridium cruentum in a sucrose—phosphate—citrate—magnesium medium. These particles showed high rates of oxygen evolution in the water‐to‐silicomolybdate reaction (2300 μmol O2.mg chl‐1.h‐1). Photosystem I, according to fluorescence emission spectra (−196°C), was greatly reduced or absent. The results demonstrate a close physical relationship of photosystem II with the phycobilisomes which are the major light harvesting antennae in this organism.
Opsin pigments formed with acyclic retinal analogues
Authors: Crouch Rosalie , Or Yat Sun
Published: July 2002

Three acyclic derivatives (3,7‐dimethyl‐10‐ethyl‐2,4,6,8‐dodecatetraenal, 3,7,10‐trimethyl‐2,4,6,8‐dodecatetraenal, and 3,7,10‐trimethyl‐2,4,6,8‐undecatetraenal) have been synthesized and the 2‐cis, 6‐cis, 2,6‐dicis and all‐trans isomers of each isolated. Unlike the undecatetraenal compound, the dodecatetraenal derivatives, have methyl groups which can mimic the C‐1 and/or C‐5 methyl group of retinal. The 6‐cis and 2,6‐dicis isomers of the dodecatetraenal compounds form photosensitive pigments with bovine opsin. No pigment is obtained with the undecatetraenal derivative. Therefore, although the retinal cyclohexyl ring is not essential for pigment formation, at least one methyl group corresponding to the C‐1 or C‐5 retinal methyl may be required for obtaining stable opsin pigments.
Absorption spectrum of cattle hypsorhodopsin
Authors: Yoshizawa Tôru , Horiuchi Shinri , Tokunaga Fumio , Sasaki Norihiro
Published: July 2002

On irradiation at liquid helium temperatures, rhodopsin is converted into hypsorhodopsin which decays to bathorhodopsin above 23 K. The absorption spectrum of cattle hypsorhodopsin (λmax = 435 nm) is found to include a new sideband around 540 nm. This sideband may be due to π* ← π transition to 1A−
g like state, which is made partially allowed by distortion of polyene chain of the retinylidene chromophore.
A single subunit P‐700 reaction center of the thermophilic cyanobacteriumMastigocladus laminosus
Authors: Muster Peter , Binder Andres , Bachofen Reinhard
Published: July 2002

The isolation and characterization of a single subunit Photosystem I reaction center of the thermophilic cyanobacteriumMastigocladus laminosusis described. The subunit isolated in 0.1% SDS is fully active in P‐700 bleaching and oxidizes cytochromecin the light. Depending on denaturing conditions, the protein appears on SDS—PAGE in the 70 kDa or 50 kDa region and contains bound chlorophyll in both forms. The 70 kDa form shows all the activities of an intact reaction center.
Plastoquinone as a mobile redox carrier in the photosynthetic membrane
Authors: Millner P.A. , Barber J.
Published: July 2002

The role of plastoquinone as a mobile redox carrier linking photosystem II and the cytochrome b
6−f complex is considered. It is proposed that plastoquinone is located primarily within the fluid bilayer‐midplane region of the thylakoid membrane and thus can move laterally at very fast rates corresponding to a microscopic diffusion coefficient of 10−6 cm2·s−1. Because of the presence of integral proteins the diffusion path will be tortuous and extended, giving rise to a sub‐macroscopic diffusion coefficient which is lower than the above value. Even so it is concluded that within the half‐time for electron donation to the cytochrome b
6−f complex there is adequate time for plastoquinone to diffuse over a distance equivalent to the radius of a granum membrane.