BINA

The current work presents a facile and green synthesis of carbon quantum dots (C-dots), which could serve as initiators for polymerization. Herein, C-dots have been synthesized from an easily available green herb, dill leaves, by a single-step hydrothermal method. These C-dots were efficiently utilized as initiators for the photopolymerization of the polymer poly(norepinephrine) (PNE) for the first time. The photopolymerization is discussed by a factorial design, and the optimized synthesis conditions were evaluated by a third-order regression model of three reaction parameters: monomer concentration, C-dots concentration, and UV exposure time. The sign convention of the factorial design mode indicated that monomer concentration and time of exposure are the most important factors for polymerization. The photopolymerized poly(norepinephrine) was extensively studied using Fourier transform infrared (FTIR …

H08. 00001: Observation of coherent oscillations in molecular association from ultra cold thermal gasץ

The parasite Trypanosoma brucei cycles between an insect and a mammalian host and is the causative agent of sleeping sickness. Here, we performed high‐throughput mapping of pseudouridines (Ψs) on mRNA from two life stages of the parasite. The analysis revealed ~273 Ψs, including developmentally regulated Ψs that are guided by homologs of pseudouridine synthases (PUS1, 3, 5, and 7). Mutating the U that undergoes pseudouridylation in the 3′ UTR of valyl‐tRNA synthetase destabilized the mRNA level. To investigate the mechanism by which Ψ affects the stability of this mRNA, proteins that bind to the 3′ UTR were identified, including the RNA binding protein RBSR1. The binding of RBSR1 protein to the 3′ UTR was stronger when lacking Ψ compared to transcripts carrying the modification, suggesting that Ψ can inhibit the binding of proteins to their target and thus affect the stability of mRNAs …

We measured the photon count rate (PCR) and dark count rate (DCR) of a superconducting nanowire single photon detector (SNSPD) exposed to either a DC magnetic field (up to 60 mT) or to a low-amplitude oscillating field ( 0.12 – 0.48 mT, up to 50 kHz). In both cases, the results show an increase in the PCR and the DCR as the DC field or the frequency of the AC field increase. However, the ratio DCR/(PCR + DCR) increases significantly with an increasing DC field, whereas this ratio is approximately constant as the frequency of the AC field increases up to frequencies in the kHz regime. The results suggest a more favorable effect of AC fields on the operation of the SNSPD.

We have studied the effect of doping on the temperature performance of a split-well (SW) direct-phonon (DP) terahertz (THz) quantum-cascade laser (QCL) scheme supporting a clean three-level system. Achieving a system that is as close as possible to a clean n-level system proved to be the strategy that led to the best temperature performance in THz-QCLs. We expected to obtain a similar improvement to that observed in resonant-phonon (RP) schemes after increasing the carrier concentration from 3× 10 10 cm− 2 to 6× 10 10 cm− 2. Our goal was to improve the temperature performance by increasing the doping, ideally the results should have improved. To our surprise, in the devices we checked, the results show the contrary. Although an increase in doping had previously shown a positive effect in RP schemes, our results indicated that this does not happen with SW–DP devices. However, we observed a significant increase in gain broadening and a reduction in the dephasing time as the doping and temperature increased. We attribute these effects to enhanced ionized-impurity scattering (IIS). The observation and study of effects related to dephasing included in our experimental work have previously only been possible via simulation. View Full-Text

Long-range structures and dynamics are central to coordination chemistry, yet are hard to identify experimentally. By combining polarized low-frequency Raman spectroscopy with single crystal XRD to study barium nitrilotriacetate, a metal-organic coordination polymer and a useful pyrolysis precursor, we could assign Raman peaks experimentally to layer shear motions and perpendicular hydrogen bond vibrations. These directional long-range interactions further determined the preferred fracture directions during crystallization, establishing an important link between structural motifs in the precursor, and the porosity of the carbon it yields upon pyrolysis.

Chaos is generally considered a nuisance, inasmuch as it prevents long-term predictions in physical systems. Here, we present an easily accessible approach to undo deterministic chaos in arbitrary two-dimensional optical chaotic billiards, by introducing spatially varying refractive index therein. The landscape of refractive index is obtained by a conformal transformation from an integrable billiard. Our study shows that this approach is robust to small fluctuations. We show further that trajectory rectification can be realized by relating chaotic billiards with non-Euclidean billiards. Finally, we illustrate the universality of this approach by extending our investigations to arbitrarily deformed optical billiards. This work not only contributes in controlling chaos, but provides a novel pathway to the design of billiards and microcavities with desired properties and functionalities.

Is it possible that a measurement of a spin component of a spin-1/2 particle yields the value 100? In 1988 Aharonov, Albert and Vaidman argued that upon pre-and postselection of particular spin states, weakening the coupling of a standard measurement procedure ensures this paradoxical result 1. This theoretical prediction, called weak value, was realised in numerous experiments 2, 3, 4, 5, 6, 7, 8, 9, but its meaning remains very controversial 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, since its “anomalous” nature, ie, the possibility to exceed the eigenvalue spectrum, as well as its “quantumness” are debated 20, 21, 22. We address these questions by presenting the first experiment measuring anomalous weak values with just a single click, without the need for statistical averaging. The measurement uncertainty is significantly smaller than the gap between the measured weak value and the nearest eigenvalue. Beyond …

Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) 2015-04-06

Cancer immunotherapy focuses on inhibitors of checkpoint proteins, such as programmed death ligand 1 (PD-L1). Unlike RAS-mutated lung cancers, EGFR mutant tumors have a generally low response to immunotherapy. Because treatment outcomes vary by EGFR allele, intrinsic and microenvironmental factors may be involved. Among all non-immunological signaling pathways surveyed in patients’ datasets, EGFR signaling is best associated with high PD-L1. Correspondingly, active EGFRs stabilize PD-L1 transcripts and depletion of PD-L1 severely inhibits EGFR-driven tumorigenicity and metastasis in mice. The underlying mechanisms involve the recruitment of phospholipase C-γ1 (PLC-γ1) to a cytoplasmic motif of PD-L1, which enhances PLC-γ1 activation by EGFR. Once stimulated, PLC-γ1 activates calcium flux, Rho GTPases, and protein kinase C, collectively promoting an aggressive phenotype. Anti-PD …

The emergence of bacteria resistant to antibiotics and the resulting infections are increasingly becoming a public health issue. Multidrug-resistant (MDR) bacteria are responsible for infections leading to increased morbidity and mortality in hospitals, prolonged time of hospitalization, and additional burden to financial costs. Therefore, there is an urgent need for novel antibacterial agents that will both treat MDR infections and outsmart the bacterial evolutionary mechanisms, preventing further resistance development. In this study, a green synthesis employing nontoxic lignin as both reducing and capping agents was adopted to formulate stable and biocompatible silver–lignin nanoparticles (NPs) exhibiting antibacterial activity. The resulting silver–lignin NPs were approximately 20 nm in diameter and did not agglomerate after one year of storage at 4 °C. They were able to inhibit the growth of a panel of MDR clinical …

Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) 2017-05-16

High-photon-energy electromagnetic radiations in the forms of X-rays and c-rays and particles such as neutrons and electrons are routinely used for various imaging and diffraction modalities with applications ranging from materials science and chemistry to biomedical imaging and industrial imaging. They provide important unique information on the structure and the functionality of the investigated samples that other methods cannot provide. However, despite the extensive efforts, there are several critical challenges that hamper further improvements in the performances of the modalities and thus limit the accessible information. Interestingly, while very different in the way high-photon-energy radiation and particles interact with the sample, imaging modalities that utilize them share similar challenges. Among the major challenges are damage to the sample when it is exposed to the probe beam and the limited resolution of the images (for electrons the resolution can be high but only for small samples). The origin of the damage is the large quanta of energy that is absorbed during the interaction between the probe and the sample. The resolution is limited since magnification and point-to-point imaging are very challenging with high energy photons and particles due to the limited available optics. For some applications, the sensitivity and the slow time response are also obstructive. Traditionally, two approaches for imaging have been utilized. In the first approach, a wide beam irradiates the sample, and a pixelated detector is mounted after the sample to measure the intensity distribution of the transmitted or scattered beam. In the second approach, a …

The coronavirus SARS-CoV-2 main protease, Mpro, is conserved among coronaviruses with no human homolog and has therefore attracted significant attention as an enzyme drug target for COVID-19. The number of studies targeting Mpro for in silico screening has grown rapidly, and it would be of great interest to know in advance how well docking methods can reproduce the correct ligand binding modes and rank these correctly. Clearly, current attempts at designing drugs targeting Mpro with the aid of computational docking would benefit from a priori knowledge of the ability of docking programs to predict correct binding modes and score these correctly. In the current work, we tested the ability of several leading docking programs, namely, Glide, DOCK, AutoDock, AutoDock Vina, FRED, and EnzyDock, to correctly identify and score the binding mode of Mpro ligands in 193 crystal structures. None of the codes …

We demonstrate that free electrons can be used as ultrafast non-destructive photon detectors. Particularly, we show how one can measure photon statistics, temporal coherence, and implement full quantum state tomography using free electrons.

Fluorescence standards allow for quality control and for the comparison of data sets across instruments and laboratories in applications of quantitative fluorescence. For example, users of microscopy core facilities can expect a homogenous and time‐invariant illumination and an uniform detection sensitivity, which are prerequisites for imaging analysis, tracking or fluorimetric pH or Ca2+‐concentration measurements. Similarly, confirming the three‐dimensional (3‐D) resolution of optical sectioning microscopes calls for a regular calibration with a standardized point source. The test samples required for such measurements are typically different ones, they are often expensive and they depend much on the very microscope technique used. Similarly, the ever‐increasing choice among microscope techniques and geometries increases the demand for comparison across instruments. Here, we advocate and …

A central issue in protein electronics is how far the structural stability of the protein is preserved under the very high electrical field that it will experience once a bias voltage is applied. This question is studied on the redox protein Azurin in the solid‐state Au/protein/Au junction by monitoring protein vibrations during current transport under applied bias, up to ≈1 GV m−1, by electrical detection of inelastic electron transport effects. Characteristic vibrational modes, such as CH stretching, amide (NH) bending, and AuS (of the bonds that connect the protein to an Au electrode), are not found to change noticeably up to 1.0 V. At >1.0 V, the NH bending and CH stretching inelastic features have disappeared, while the AuS features persist till ≈2 V, i.e., the proteins remain Au bound. Three possible causes for the disappearance of the NH and CH inelastic features at high bias, namely, i) resonance transport, ii …

Aqueous salt batteries with high concentrations of salt or water in salt aqueous systems have received considerable attention with focus on improving working voltage range and energy density. Here, the effect of NaClO4 salt concentration on the electrochemical performance and stability of tunnel-type Na0. 44MnO2 (NMO) cathodes and organic polyimide (PI) derivative anodes was studied. High capacity retention and 100% coulombic efficiency were shown for NMO/PI full cell in saturated NaClO4 electrolyte. A high, stable capacity of 115 mAh/g was achieved for the PI anode material, and the full cell showed a stable capacity of 41 mAh/g at 2C rate for 430 cycles (calculated for the weight of NMO cathode). Even at a fast 5C rate, a discharge capacity of 33 mAh/g was maintained for 2,400 prolonged cycles with nearly 100% efficiency. The full cell device can achieve an average voltage of 1 V with energy density of 24 Wh/kg. This study highlights concentrated sodium perchlorate as a promising electrolyte solution for stabilization enhancement of electrochemical performance in aqueous media. of electrodes and

In this research we present a basis for a solution for Age Related Macular Degeneration (AMD) patients. The proposed solution is a binocular passive optical device composed of a contact lens and spectacles, both coated by light-reflecting material in order to generate a Fabry-Perot-like resonator. This bounces the light rays several times between the two surfaces, achieving optical simultaneous magnifications for near and far distances as needed for AMD patients in early stages of the disease. Our work has two parts: numerical simulation of the magnification achieved by the device and a clinical experiment, with non-AMD patients, in which we examined visual skills with simultaneous magnifications. The numerical simulations proved mathematically that the device can produce several different magnifications simultaneously, Zemax simulations confirmed this. In the clinical study, simultaneous vision was found to …