Genomic variation and point mutations analysis of Indian COVID-19 patient samples submitted in GISAID database

Corona virus disease 2019 (COVID-19) endemic has havoc on the world; the causative virus of the pandemic is SARS CoV-2. Pharmaceutical companies and academic institutes are in continuous efforts to identify anti-viral therapy or vaccines, but the most significant challenge faced is the highly evolving genome of SARS CoV-2, which is imparting evolutionary selective benefits to the virus. To understand the viral mutations, we have retrieved nine hundred and thirty-four samples from different states of India via the GISAID database and analyzed the frequency of all types of point mutation in all structural, non-structural proteins, and accessory factors of SARS CoV-2. Spike glycol protein, nsp3, nsp6, nsp12, N and NS3 were the most evolving proteins. High frequency point mutations were Q496P (nsp2), A380V (nsp4), A994D (nsp3), L37F (nsp6), P323L & A97V (nsp12), Q57H (ns3), D614G (S), P13L (N), R203K (N), G204R (N) and S194L (N).     

A micro/nanocasting method for replicating soft micro/nanosurface structures using a dynamic electrical field

We propose a new electric field-induced micro/nanocasting method to replicate soft patterns using micro/nanocasting techniques without pressure. The process uses an alternating current (AC) electrical field and rotation of one electrode, generating a dynamic electrical field that induces electrokinetic flow motion in a dielectric solution (polydimethylsilane, PDMS). We used a lotus leaf as a replication template and characterised the PDMS flow motion to observe the effects of various process parameters (e.g., electrical field strength, rotation speed of an electrode, and electrode shape). The unstable flow motion was significantly dependent on the processing parameters, especially the rotation speed of the electrode. Using the optimised processing conditions, the replication efficiency was about 88%. We believe that this method has potential for fabricating soft micro/nanosized structures.     

Replication and surface properties of micro injection molded PLA/MWCNT nanocomposites

Multi-walled carbon nanotube (MWCNT) reinforced polylactide (PLA) nanocomposites were injected molded into a mold with micro needle patterns. In order to alleviate the hesitation effect caused by an increased melt viscositgy of PLA/CNT nanocomposites, the effects of the injection speed and holding pressure on the replication property were investigated. The effects of MWCNTs on the crystallization, thermal behavior, replication properties, replication and surface properties of micro injection molded PLA/CNT nanocomposites were investigated. An analysis of crystallinity and thermal behavior indicated that the MWCNTs promoted the unique α’ to α crystal transition of PLA, leading to an enhancement of surface modulus and hardness, as measured using a nanoindentation technique. The specific interaction between PLA and MWCNTs was characterized using an equilibrium melting point depression technique. Furthermore, the MWCNTs increased the activation energy for thermal degradation of PLA due to the physical barrier effect. The improved replication quality of the microfeatures in the PLA/MWCNT nanocomposites has been achieved by elevating injection speed and holding pressure, which enhances the polymer filling ability within the micro cavity. A replication ratio greater than 96% for the micro injection molded PLA/CNT nanocomposites were achieved at holding pressure of 100 MPa and injection speed of 120 mm/s. This study shows that processing conditions significantly influence the replication and surface properties of micro injection molded PLA/CNT nanocomposites.     

Replication of microchannel structures in polymers using laser fabricated glass–ceramic stamp

A new microreplication process with photo-etchable glass–ceramic stamps and polymers is presented. This process has two main advantages: a rapid master fabrication with a laser process and a flexible replication process compared with conventional nano- or microreplication technique on polymers. Photo-etchable glass–ceramics are used for the master stamp. Micropatterns can be rapidly transferred with a laser direct writing process and the removal of the glass–ceramics can be efficiently achieved with a wet etching process. Therefore, microstructures with flat bottom surfaces and straight sidewall structures can be obtained, which is difficult in the laser direct writing process. A microstamping process of applying heat and pressure, also referred to as hot embossing lithography or microstamping, can replicate microstructures on polymer surfaces. In this work, the fabricated glass–ceramic stamps are used for the replication process and various replicated polymer microstructures are presented.     

微透镜阵列的铸塑复制技术

在光刻热熔成型以及电铸复制得到的微透镜阵列镍板基础上,采用静态铸塑技术,得到了高质量的PMMA微透镜阵列。本文介绍了静态铸塑的聚合反应理论基础、模具设计以及工艺过程。最后对微透镜阵列的复制精度进行分析,结果表明复制精度优于0.5μm.     

Anisotropic spin-glasses with broken replica symmetry

A simple mechanism of replica symmetry breaking for spin-glass, as suggested by Parisi, has been used to solve the anisotropic spin-glass model of Sherrington and Ghatak. Temperature variation of the correlation parameters and the resulting variations with the temperature of the thermodynamic quantities like internal energy, specific heat and entropy have been evaluated. It is found that the anisotropy has considerable effect on the properties of the spin system. At low temperatures, the specific heat varies asT ². However, the entropy is positive for temperatures above 0.1°K, which is a considerable improvement on the results of Sherrington and Ghatak. The results are expected to be in good agreement with experiment or computer simulation studies near transition temperatures.     

Inspecting the foundations of claims about cognitive demand and student learning: A citation analysis of Stein and Lane (1996)

Educational research communities bear responsibility for establishing a substantial body of evidence to support claims that drive the field. For example, one commonly accepted claim is that there is a relationship between the cognitive demand of mathematical task enactments and students’ learning. One study that is often cited in association with this claim is Stein and Lane (1996), and in 44% of those citations, Stein and Lane (1996) is the sole reference. Citation analysis reveals that many of these claims go beyond the warrants provided by the Stein and Lane study, either by granting more confidence in the relationship than the study design allows or by phrasing the claim as a causal relationship between cognitive demand and student learning. A few other studies are occasionally cited in conjunction with Stein and Lane (1996) and are summarized in this article, but there remains a need for replication studies to provide better empirical support for claims about cognitive demand and student learning and to refine our shared understanding.     

Replication and shortfall risk in a binomial model with transaction costs

The shortfall risk is defined as the optimal mean value of the terminal deficit produced by a self-financing portfolio whose initial value is smaller than what is required to replicate a contingent claim. In this paper we look for an explicit expression for it, as well as for the optimal strategy, when the market model is a binomial model with proportional transaction costs. We first study replication of European claims which satisfy suitable assumptions. We then investigate the shortfall minimization problem in a framework very similar to that without transaction costs. The author thanks the referee for useful comments on an earlier version of the present paper.     

Replication and Evolution in Inorganic Systems

Using layer silicates as models, the principle of replication, i.e. the spontaneous self-multiplication of a carrier of information, can be shown to be a general property of certain macromolecular systems. Errors in replication and feedback together with environmental influences may lead to mutants with higher or lower replication rates, thus enabling evolution. In the light of these findings, the question of whether or not chemical evolution resulted directly in the nucleic acid/protein system, i.e. the genetic principle common to all living systems known up to now, has to be answered. It seems conceivable that as a first step a much simpler replicating system was formed: such a system might then have undergone an evolution of replicating systems, resulting in the final nucleic acid/protein system.