Two-dimensional (2D) magnets with intrinsic ferromagnetic/antiferromagnetic (FM/AFM) ordering are highly desirable for future spintronic devices. However, the direct growth of their crystals is in its infancy. Here we report a chemical vapor deposition approach to controllably grow layered tetragonal and non-layered hexagonal FeTe nanoplates with their thicknesses down to 3.6 and 2.8 nm, respectively. Moreover, transport measurements reveal these obtained FeTe nanoflakes show a thickness-dependent magnetic transition. Antiferromagnetic tetragonal FeTe with the Néel temperature ( T N ) gradually decreases from 70 to 45 K as the thickness declines from 32 to 5 nm. And ferromagnetic hexagonal FeTe is accompanied by a drop of the Curie temperature ( T C ) from 220 K (30 nm) to 170 K (4 nm). Theoretical calculations indicate that the ferromagnetic order in hexagonal FeTe is originated from its concomitant lattice distortion and Stoner instability. This study highlights its potential applications in future spintronic devices.

The beautiful interplay between light and matter can give rise to many striking physical phenomena, surface plasmon resonance (SPR) being one of them. Plasmonic immunosensors monitor refractive index changes that occur as a result of specific ligand–analyte or antibody–antigen interactions taking place on the sensor surface. The coronavirus disease (COVID‐19) pandemic has jeopardized the entire world and has resulted in economic slowdown of most countries. In this work, a model of a sandwich plasmonic biosensor that utilizes gold nanorods (Au NRs) for the detection of COVID‐19 SARS‐CoV‐2 spike protein is presented. Simulation results for different prismatic configurations for the basic Kretschmann layout are presented. It is found that a BK7 glass prism‐based SPR sensor has an incremental sensitivity of 111.11 deg RIU−1. Additionally, using Comsol Multiphysics the electric field enhancement observed for various aspect ratios and layouts of Au NRs are discussed in depth.

Plants with self‐incompatibly (SI) frequently exhibit variable expression of this trait. The study reported here investigates the breakdown of SI in a perennial bellflower (Campanula rapunculoides) using a standard quantitative genetics approach to examine the relative influences of genotype, prior fruit‐set and floral age on seed‐set from self‐pollinations with standardized pollen loads. Cross‐pollen was used on separate flowers for comparison. The results obtained indicate that genotype (clone) explained a significant amount of the total variation and plants with few developing fruits showed stronger expression of SI on young flowers, and weaker expression of SI on old flowers than plants with many fruits (fruit‐by‐floral‐age interaction, P<0.02). A second experiment determined that the stigmatic curling accompanying floral age does not influence expression of SI. A significant clone‐by‐floral‐age interaction suggests that continuous variation in self seed‐set of putatively SI species may be the result of genotype‐by‐environment interactions. It is concluded that SI is a phenotypically plastic trait in C. rapunculoides and its breakdown responds to conditions that are indicative of low pollinator activity.

The arginine-rich domains of several RNA-binding proteins have been shown to bind their cognate RNAs with high affinities and specificities as isolated peptides, adopting different conformations within different complexes. The sequence simplicity and structural diversity of the arginine-rich motif has made it a good framework for constructing combinatorial libraries and identifying novel RNA-binding peptides, including those targeted to the HIV Rev response element (RRE). Here we describe a modified transcription antitermination reporter assay engineered with kanamycin resistance that enables larger in vivo screens (∼ 10 9 sequences) than previously possible. We show that the assay detects only specific RNA-protein complexes, and that binders are enriched at least 300-fold per round of selection. We screened a large peptide library in which amino acids with charged, polar, and small side chains were randomly distributed within a polyarginine framework and identified a set of high affinity RRE-binding peptides. Most contain glutamine at one particular peptide position, and the best peptides display significantly higher antitermination activities than Rev or other previously described high-affinity RRE-binding peptides. The kanamycin antitermination (KAN) assay should be useful for screening relatively large libraries and thereby facilitate identification of novel RNA binders.

We live in a digitized era, where we are completely surrounded by a plethora of automated electronic systems, be it a smart home energy controller or a self‐operated diagnostic kiosk in a clinic. With the recent advent of one‐dimensional (1D) and two‐dimensional (2D) nanomaterials like carbon nanotube (CNT) and graphene, the world of electronics has revolutionized with state‐of‐the‐art product paradigms. These nanomaterials possess desirable features of large surface area, excellent electrical conductivity, and high mechanical strength. Electronic devices made out of these materials have the added advantages of being flexible, light‐weight, and durable. Thus, present‐day devices that utilize these substances as channel or electrode materials have been able to undergo a positive transformation as compared with conventional structures. Flexibility and bendability are some of the coveted aesthetics of modern‐day electronics and the use of these 1D and 2D nanomaterials imparts such features to the devices, without having to compromise on key output characteristics like sensitivity and efficiency. In this short review, we discuss about various new configurations that are based on graphene, CNT, and other materials like transition metal dichalcogenides, and how these materials have been able to metamorphose the attributes of conventional devices.image

The two identical genomic RNA strands inside each HIV-1 viral particle are linked through homodimerization of an RNA stem-loop, termed SL1, near their 5P P ends. SL1 first dimerizes through a palindromic sequence in its loop, forming a transient kissing-loop complex which then refolds to a mature, linear duplex. We previously reported the NMR structure of a 23-base truncate of SL1 in kissing-dimer form, and here report the high-resolution structure of its linear isoform. This structure comprises three short duplex regions^derived from the central palindrome and two stem regions of each strand, respectivelyŝ eparated by two bulges that each encompass three unpaired adenines flanking the palindromes. The stacking pattern of these adenines differs from that seen in the kissing-loop complex, and leads to greater colinear base stacking overall. Moreover, the mechanical distortion of the palindrome helix is reduced, and base pairs ruptured during formation of the kissing-loop complex are re-established, so that all potential Watson-Crick pairs are intact. These features together likely account for the greater thermodynamic stability of the mature dimer as compared to its kissing-loop precursor.z 1999 Federation of European Biochemical Societies.

Counting cells is often a necessary but tedious step for in vitro cell culture. Consistent cell concentrations ensure experimental reproducibility and accuracy. Cell counts are important for monitoring cell health and proliferation rate, assessing immortalization or transformation, seeding cells for subsequent experiments, transfection or infection, and preparing for cell-based assays. It is important that cell counts be accurate, consistent, and fast, particularly for quantitative measurements of cellular responses.Despite this need for speed and accuracy in cell counting, 71% of 400 researchers surveyed 1 who count cells using a hemocytometer. While hemocytometry is inexpensive, it is laborious and subject to user bias and misuse, which results in inaccurate counts. Hemocytometers are made of special optical glass on which cell suspensions are loaded in specified volumes and counted under a microscope. Sources of errors in hemocytometry include: uneven cell distribution in the sample, too many or too few cells in the sample, subjective decisions as to whether a given cell falls within the defined counting area, contamination of the hemocytometer, user-to-user variation, and variation of hemocytometer filling rate 2 .To alleviate the tedium associated with manual counting, 29% of researchers count cells using automated cell counting devices; these include vision-based counters, systems that detect cells using the Coulter principle, or flow cytometry 1 . For most researchers, the main barrier to using an automated system is the price associated with these large benchtop instruments 1 .The Scepter cell counter is an automated handheld device that offers the automation and accuracy of Coulter counting at a relatively low cost. The system employs the Coulter principle of impedance-based particle detection 3 in a miniaturized format using a combination of analog and digital hardware for sensing, signal processing, data storage, and graphical display. The disposable tip is engineered with a microfabricated, cellsensing zone that enables discrimination by cell size and cell volume at sub-micron and sub-picoliter resolution. Enhanced with precision liquid-handling channels and electronics, the Scepter cell counter reports cell population statistics graphically displayed as a histogram. Video LinkThe video component of this article can be found at

Human immunodeficiency virus type 1 (HIV-1) transcription is regulated by the viral Tat protein, which relieves a block to elongation by recruiting an elongation factor, P-TEFb, to the viral promoter. Here, we report the discovery of potent Tat inhibitors that utilize a localization signal to target a dominant negative protein to its site of action. Fusing the Tat activation domain to some splicing factors, particularly to the Arg-Ser (RS) domain of U2AF65, creates Tat inhibitors that localize to subnuclear speckles, sites where pre-mRNA processing factors are stored for assembly into transcription complexes. A U2AF65 fusion named T-RS interacts with the nonphosphorylated C-terminal domain of RNA polymerase II (RNAP II) via its RS domain and is loaded into RNAP II holoenzyme complexes. T-RS is recruited efficiently to the HIV-1 promoter in a TARindependent manner before RNAP II hyperphosphorylation but not to cellular promoters. The "preloading" of T-RS into HIV-1 preinitiation complexes prevents the entry of active Tat molecules, leaving the complexes in an elongation-incompetent state and effectively suppressing HIV-1 replication. The ability to deliver inhibitors to transcription complexes through the use of targeting/localization signals may provide new avenues for designing viral and transcription inhibitors.