Current Chinese Science - Volume 1, Issue 4, 2021

Background: MicroRNAs (miRNAs) are small endogenous non-coding RNAs that are roughly 18-22 nucleotides long. They play important roles in different natural procedures. As of now, little is known about their role in plant stress. The use of computational homology-based techniques for Expressed Sequence Tags (ESTs) with the Ambros exact method and other structural component criteria is a rational approach for the disclosure and confinement of conserved miRNAs from several species. Aims: The study aimed to identify novel stress induced miRNAs in tomato, using a computational approach. Methods: We used previously known sequences of mature miRNAs of different plants; Vitis, Oryza, Triticum and Sorghum for the prediction of potential novel miRNAs in tomatoes. The hairpin strucutres of miRNAs were predicted, their functional annotations were performed, and the targeted genes were identified. Results: Only two miRNAs were predicted and validated to be novel belonging to the family of miRNA1301. The expression analysis of the novel miRNAs showed their significant role in the growth and development of the respective tissues. We have found that the miRNAs in the leaf are highly conserved related to the seed. This discovery significantly broadens the understanding of the functions of miRNA in tomatoes. MiR1301 was found to play a role in transcriptional activation and transporter activity, also involved in ubiquitin-protein ligase translation and transcription. 7 potential targets were predicted for the two identified miRNAs. Conclusion: Identification of new miRNAs and their target genes will establish the potential roadmap for understanding the core regulatory interactions during abiotic stress in S. Lycopersicum.

Background: In 2020, when the World Health Organization (WHO) declared COVID-19 (Coronavirus disease 2019) a pandemic, many of the public managers faced challenging situations in their cities due to the simultaneous loss of lives and jobs. In this regard, this study aims to propose a concise model that considers variables like the number of deaths, lethality of the virus, number of jobs, and taxes collected by city halls. Our study considers these issues in providing a relevant response and consistent answer to deliberations on the way forward. Methods: Mathematical modeling was used to analyze the interaction between the agents involved, and computer simulation was chosen to collect results. Results: Changing the lockdown level (fixed and variable), the results of number of deaths per week, the total number of unemployed, cost of companies, and so on are shown. The levels of lockdowns adopted are: fixed (0%, 40%, 80%, 100%) and variable (30% to 60% and 80% to 40%). The results show that for the input data considered, the 0% lockdown (LD) policy is more effective for the economy and tax collection and also succeeds in repressing the effects on the number of deaths. The comparison between with pandemic and without pandemic is provided (in percentage). Adopting a 0% LD, it appears to be worse in couple of weeks compared to other LD levels with regard to the percentage increase in the number of deaths due to the pandemic virus (in particular, + 626% for the 4th week while + 398% for 100% LD). Fortunately, in absolute numbers this quantity is considered low in relation to the size of the population. The great advantage is seen mainly in tax collection and number of unemployment generated. For a 0% LD, in the worst scenario, the tax collection is reduced by 23.68% in the 8th week, while the worst (100% LD) the drop in tax collection reaches 91.70%. The highest percentage of unemployed generated for 0% LD occurs is in the 16th week, and for the worst LD (100%), the percentage of generation of unemployed number reaches 106.64%. The number of deaths caused by unemployment, for the worst case of 0% LD also occurs in the 16th week, with 46.65% while for the 100% LD, the percentage of deaths has increased by 97.48%. Conclusion: This study shows that implementing the lockdown did not bring expected benefits, because instead of reducing the number of deaths due to the COVID-19, individuals tend to die more from other causes.

Background: Li-air batteries have attracted huge attention in recent years due to the ultrahigh theoretical specific energy. The development of high-performance and low-cost cathode electrocatalysts for Li-air batteries is of great importance and has faced great challenges. Objective: This study aimed to design a new kind of cathode catalyst material for Li-air batteries. Methods: In this study, MoS2-rGO-Co was fabricated through a hydrothermal treatment following a chemical reduction process. A series of characterizations, including XRD, SEM, Raman, and XPS, were employed to explore the structure, morphology, and composition information of MoS2-rGOCo. The performance and stability of the MoS2-rGO-Co-based Li-air battery were tested in electrochemical measurements. Results: A composite of Co nanoparticles decorated flower-like MoS2 nanosheets grown on reduced graphene oxide (rGO), denoted as MoS2-rGO-Co, was successfully prepared. The MoS2-rGO-Cobased Li-air battery showed superior electrochemical performance with a capacity of 6591 mAh g^-1, a reduced overpotential of ∼500 mV, and enhanced cycling stability. Conclusion: Through a combination of hydrothermal method and chemical reduction, the hybrid cathode catalyst of MoS2-rGO-Co was successfully synthesized, which exhibited great electrochemical performance and stability in the Li-air battery. The high electrocatalytic activity of the composite benefits from the synergistic effect of MoS2 and Co as well as the rGO substrate, in which the high conductivity substrate provides the efficient electron transfer channel and the optimized electron structure of active components improves the electrocatalytic activity in battery reaction. All these advantages make great contributions to the superior performance of Li-air batteries. Our strategy paves a new way for exploring excellent electrocatalysts applied to other energy fields.

Background: Great achievements have been made in improving the power conversion efficiencies of solar cells. However, the price of photovoltaic (PV)-generated electricity still cannot compete with that of conventionally generated power. Thus, novel solar cells made from non-toxic, earth-abundant, and chemically stable materials are desirable to decrease the costs of PV electricity generation. Objective: All-oxide solar cells are a promising next-generation PV technology, fulfilling the requirement of low-cost manufacturing under ambient conditions. This work aims to search for nontoxic, earth-abundant, and chemically stable narrow-bandgap semiconductors for energy applications like all-oxide solar cells. Methods: This work examines a family of perovskite rare-earth (i.e., Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Yb) orthoferrites with XRD analysis, SEM, photoresponse, absorption spectra, Xray photoelectron spectroscopy, fluorescence spectra measured with the laser Raman spectrometer, valence band spectra, the Kelvin probe, the Hall Effect experiment, and theoretical calculation on band structure and the density of states, to screen for the narrow-bandgap semiconductors. Results: The novel Pb-free perovskite narrow-bandgap absorbers, CeFeO3, PrFeO3, TbFeO3, DyFeO3, HoFeO3, and YbFeO3, which are earth-abundant and non-toxic, were screened out potentially for use in all-oxide solar cells or other photovoltaic and optoelectronic applications. Among them, YbFeO3 is approved, having an indirect bandgap of approximately 1.0 eV with a maximum Shockley-Queisser efficiency of 31% for single p-n junction solar cells. Conclusion: The chemically stable, non-toxic, earth-abundant, and narrow-bandgap semiconductors of rare-earth orthoferrites promisingly serve as absorbers, photocatalysts, photoelectrodes, photodetectors, and photoelectronic materials. This work breaks new ground in the search for narrow bandgap all-oxide semiconductors potential for energy applications.

Background: Topological insulator (TI), Bi2Te3 is a new class of quantum materials. Having ultralow dissipation surface states, TIs hold great promise toward different potential applications. Micro-Raman spectroscopy is a conventional and non-destructive technique, which has been widely used to characterize the structural and electronic properties of thermoelectric materials. Objective: The objective of this study is to review power dependent and temperature dependent Raman spectra of B2Te3 nanoflakes on SiO2/Si substrate to estimate the temperature coefficient and thermal conductivity of these flakes for possible application of this material in thermoelectrics. Methods: Bi2Te3 flakes of different thicknesses were mechanically exfoliated from high-quality bulk Bi2Te3 crystal using scotch tape on 300 nm SiO2/ Si substrates. The power dependent and temperature dependent Raman spectra were acquired with the help of HORIBA LabRAM confocal micro- Raman system in a backscattering geometry. Results: The observed power dependent and temperature dependent Raman spectra of Bi2Te3 nanoflakes follow the same trend as discussed in various pieces of literature. From temperature coefficient and power coefficient values, the in-plane thermal conductivity has been estimated, which is found to be in the order of 102 W/m-K. The enhancement in the thermal conductivity suggests that the underlying substrate significantly affects the heat dissipation of the Bi2Te3 flake based on the coupling strength with Bi2Te3. Conclusion: This work provides a good platform to understand the role of the substrate on the thermal conductivity of exfoliated Bi2Te3 nanoflakes and this study can be extended to other substrates.

Background: Intramammary infections constitute major animal health and economic problem in commercial dairy goat farms, being responsible for decreases in milk yield, alter milk composition, and lower milk quality. Objectives: This paper reviews the published literature during the last three decades, highlighting the multiplicity of non-infectious and infectious factors that influence somatic cell count (SCC). Besides that, it intends to contribute to understanding the conventional diagnostic methods and their limitations, and supports the implementation of new technologies for efficient mastitis control, including the use of infrared thermography and ultrasonography. Methods: A search on Medline, ScienceDirect, and University Institutional Repositories databases was performed using “goats, AND mastitis OR intramammary infections OR somatic cells count” for publications from 1990 to present (2020). Results: A total of 144 publications were selected. The SCC is the most important criteria to evaluate the inflammatory status of the mammary glands in goats, but several non-infectious factors (e.g., phenotypic, reproductive, lactational factors) should be taken into consideration for its interpretation. Bacteria and fungi as well as lentivirus are commonly responsive for intramammary infections. Intermittent secretion or environmental contamination of milk pathogens, costs, and time delay poses challenges using conventional diagnostic methods. Ultrasonographic and thermographic techniques applied to the udder seem to be of diagnostic value in acute and chronic mastitis. Conclusion: Unlike other ruminants species, non-infectious factors have a major impact on SCC which should be taken in account for mastitis diagnosis, and according to milk pathogens detection. Further research in imagological techniques is needed to accurately contribute to implant new mastitis control strategies.