Current Chinese Science - Volume 1, Issue 5, 2021

Jet impingement in engineering applications is used because of the capacity to transport high levels of heat flux from a surface of interest for cooling purposes. Thus far, based on a vast database of experiments and numerical simulations, several correlations have been established for local and average heat transfer on target surfaces as functions of relevant fluid properties and geometric parameters. In addition to these correlations, significant efforts have been made to gain fundamental understanding of jet impingement in varying configurations. However, the physics governing heat transfer by jet impingement is conjectured and even unclear. Thus, this article collates and discusses recent advances in fluidic mechanisms underlying the heat transfer by submerged jet impingement on a convex surface. The fluid properties developed on a convex surface due to jet impingement with varied characteristics, including jet-to-target surface spacing, interchange their primary roles in heat transfer from/to a convex surface. Particularly, conjectures associated with relevant fluidic mechanisms that have been widely accepted, are confirmed, clarified, and corrected.

The development of fluorescent and colorimetric chemosensors for selective recognition and sensing of cations has received significant attention in recent decades attributed to their diverse applications in the area of environmental and biological sciences. Chemosensors for the detection of different ions offer advantages, such as high selectivity, sensitivity, low cost and rapid response time with versatility. Therefore, a large number of fluorescent/colorimetric chemosensors have been reported for the detection of biologically and environmentally important species. This review introduces the history, provides a general overview of the recent advances in the developments of fluorescent and colorimetric chemosensors, and discusses some innovative and representative works done by our research group and researchers in the field of chemosensors for target metal ions, such as Al³⁺, Fe³⁺, Cu²⁺, Ag⁺, Cd²⁺, Hg²⁺ and Sn²⁺ over 7 years’ period, from 2013 to 2020.

Non-coding RNAs (ncRNAs) play significant roles in various physiological and pathological proces ses via interacting with the proteins. The existing experimental methods used for predicting ncRNA-protein interactions are costly and time-consuming. Therefore, an increasing number of machine learning models have been developed to efficiently predict ncRNA-protein interactions (ncRPIs), including shallow machine learning and deep learning models, which have achieved dramatic advancements on the identification of ncRPIs. In this review, we provided an overview of the recent advances in various machine learning methods for predicting ncRPIs, mainly focusing on ncRNAs-protein interaction databases, classical datasets, ncRNA/protein sequence encoding methods, conventional machine learning-based models, deep learning-based models, and the two integration- based models. Furthermore, we compared the reported accuracy of these approaches and discussed the potential and limitation of deep learning applications in ncRPIs. Finding that the predictive performance of integrated deep learning is the best, and those deep learning-based methods do not always perform better than shallow machine learning-based methods. We discussed the potential of using deep learning and proposed a research approach on the basis of the existing research. We believe that the model based on integrated deep learning is able to achieve a higher accuracy in the prediction if substantial experimental data were available in the near future.

Background: CRISPR activation (CRISPRa) uses non-functional Cas9 endonuclease (dCas9) but retains the genome targeting ability through its single guide RNAs (sgRNAs). CRISPRa is widely used as a gene activation system exploiting its ability in recruiting various transcriptional activation domains (TADs) for enhancing expression of the target gene(s). Drought tolerant and resource-efficient crops like millets have the potential for mitigating effects of climate change and for enhancing food security. Objective: This study aimed to use the Setaria italica (foxtail millet) genome sequence in the identification of a target gene and the subsequent generation of sgRNAs for use in CRISPRa for conferring water logging tolerance that will benefit the future expansion of its cultivation area. Methods and Results: Leveraging existing RNA-seq data and information on functional studies in model plants and from other cereal species, maize and barley, have enabled the identification of candidate ERFVII from the foxtail millet genome sequence in the attempt to engineer water logging tolerance. The study provides a step-by-step example for using publicly accessible databases and bioinformatics tools from NCBI and Phytozome for the identification and characterization of the ortholog from Setaria italica. Soft berry was used for promoter annotation to obtain the transcription start site (TSS). Subsequently, CRISP-P 2.0 design tools were employed to generate and select a few efficient sgRNAs for CRISPRa that minimize potentially deleterious off-target binding. Conclusion: The study is a useful example of how to advance in genomics research including the revolutionizing CRISPR technology in Setaria italica, which can be adopted in other plant species, through the utilization of the available genome sequence.

Scintillators are currently widely used in high energy physics, nuclear physics, nuclear medical imaging, industrial exploration, security inspection and so on. The development of new applications puts forward the new requirements for scintillators, and it is becoming extremely urgent to discover the new scintillators. In recent years, perovskite materials present their advantages in the field of solar cell, light-emitting diode, laser, photodetector, memory and so on, owing to their high carrier mobility, long diffusion distance and continuously adjustable emission wavelength. Therefore, the perovskite-based scintillators have attracted great attention and interest due to their low detection threshold, high light yield, fast attenuation, and tunable emission wavelength. This review article summarizes the crystal structure and luminescence properties of organic-inorganic hybrid perovskite and inorganic perovskite scintillators. In addition, the fundamental application of perovskite scintillators for radiation detection has been discussed. The goal of this review article is to introduce the recent advances and development in perovskite scintillators, and a particular focus is given on the challenges and perspectives for their enormous potential application in nuclear medical imaging and radiation detection.

Aims: The study aimed at investigating interactions between zinc(II) complexes with different geometrical structures and relevant nitrogen donor nucleophiles at physiological pH. Background: Lack of clear distinction between the therapeutic and toxic doses of platinum drugs is a major challenge for the design of novel non-platinum DNA and protein targeting metal-based anticancer agents. The non-platinum antitumor complexes could be alternatives to platinum-based drugs due to their better characteristics and different mechanisms of action. Objective: This study could provide more information regarding the design of future zinc-based anticancer drugs, providing a better understanding of the mechanism of interactions between Zn(II) complexes and nitrogen-donor nucleophiles (important from the medical point of view), and clarifying the changes in geometrical structures of zinc(II) that are referred to structure-reactivity correlations. Methods: Mole-ratio method and UV-V is spectroscopic kinetic method have been used. Results: The results indicated additional coordination of chlorides in the first coordination sphere with changes in coordination geometry and formation of the octahedral complex anion [ZnCl4(en)]^2- while the excess of chloride did not affect the square-pyramidal structure of [ZnCl2(terpy)]. The substitutions of studied complexes and relevant nucleophiles proceeded in two consecutive reaction steps that depended on the nucleophile concentration. Octahedral complex anion [ZnCl4(en)]^2- forms rapidly and all substitution processes of this complex species should be considered. We assume that the first reaction step is accompanied by the dissociation of chloride ligands. Nucleophile 1,2,4- triazoles have shown the highest affinity toward [ZnCl2(en)], and rates of both steps were almost of the same value, indicating parallel reactions. Conclusion: The different order of reactivity of relevant N-donor ligands toward [ZnCl2(en)] and [ZnCl2(terpy)] complexes for the first reaction step occurred because of the influence of different geometrical structures of complexes, while low reaction rates for the second reactions of [ZnCl2(en)] complex with imidazole and pyrazine were a consequence of interconversion between octahedral and tetrahedral structure during substitution processes.