Staphylococcus aureus DivIB is a peptidoglycan-binding protein that is required for a morphological checkpoint in cell division

Bacterial cell division is a fundamental process that requires the coordinated actions of a number of proteins which form a complex macromolecular machine known as the divisome. The membrane-spanning proteins DivIB and its orthologue FtsQ are crucial divisome components in Gram-positive and Gram-negative bacteria respectively. However, the role of almost all of the integral division proteins, including DivIB, still remains largely unknown. Here we show that the extracellular domain of DivIB is able to bind peptidoglycan and have mapped the binding to its β subdomain. Conditional mutational studies show that divIB is essential for Staphylococcus aureus growth, while phenotypic analyses following depletion of DivIB results in a block in the completion, but not initiation, of septum formation. Localisation studies suggest that DivIB only transiently localises to the division site and may mark previous sites of septation. We propose that DivIB is required for a molecular checkpoint during division to ensure the correct assembly of the divisome at midcell and to prevent hydrolytic growth of the cell in the absence of a completed septum

Антропометрические исследования в диагностике эндокринопатий, сопровождающихся поликистозом яичников

На основе соматогенетического обследования и синдромологического анализа у больных с избыточной массой тела и поликистозом яичников выделено пять вариантов эндокринопатий и определены характерные для них особенности антропометрических показателей. Обнаружена положительная корреляционная зависимость абдоминального типа ожирения не только от повышенного содержания в крови тестостерона, но и от гиперкортизолемии.Based on somatogenic study and syndrome analysis of the patients with excessive body mass and polycystic ovary, five variants of endocrinopathy were distinguished as well as characteristic anthropometric indices were determined. A positive correlation of abdominal obesity and increased testosterone blood content as well as hypercortisolemia was revealed

Estimating Watershed Evapotranspiration with PASS. Part I: Inferring Root-Zone Moisture Conditions Using Satellite Dat

A model framework for parameterized subgrid-scale surface fluxes (PASS) has been modified and applied as PASS1 to use satellite data, models, and limited surface observations to infer root-zone available moisture (RAM) content with high spatial resolution over large terrestrial areas. Data collected during the 1997 Cooperative Atmosphere–Surface Exchange Study field campaign at the Atmospheric Boundary Layer Experiments site in the Walnut River watershed in Kansas were used to evaluate applications of the PASS1 approach to infer soil moisture content at times of satellite overpasses during cloudless conditions. Data from Advanced Very High Resolution Radiometers on the NOAA-14 satellite were collected and then adjusted for atmospheric effects by using LOWTRAN7 and local atmospheric profile data from radiosondes. The input variables for PASS1 consisted of normalized difference vegetation index and surface radiant temperature, together with representative observations of downwelling solar irradiance, air temperature, relative humidity, and wind speed. Surface parameters, including roughness length, albedo, surface conductance for water vapor, and the ratio of soil heat flux to net radiation, were estimated with parameterizations suitable for the area using satellite data and land-use information; pixel-specific near-surface meteorological conditions such as air temperature, vapor pressure, and wind speed were adjusted according to local surface forcing; and RAM content was estimated using surface energy balance and aerodynamic methods. Comparisons with radar cumulative precipitation observations and in situ soil moisture estimates indicated that the spatial and temporal variations of RAM at the times of satellite overpasses were simulated reasonably well by PASS1

Impact of substrates and quantum effects on exciton line shapes of 2D semiconductors at room temperature

Exciton resonances in monolayer transition-metal dichalcogenides (TMDs) provide exceptionally strong light-matter interaction at room temperature. Their spectral line shape is critical in the design of a myriad of optoelectronic devices, ranging from solar cells to quantum information processing. However, disorder resulting from static inhomogeneities and dynamical fluctuations can significantly impact the line shape. Many recent works experimentally evaluate the optical properties of TMD monolayers placed on a substrate and the line shape is typically linked directly to the material's quality. Here, we highlight that the interference of the substrate and TMD reflections can strongly influence the line shape. We further show how basic, room-temperature reflection measurements allow investigation of the quantum mechanical exciton dynamics by systematically controlling the substrate reflection with index-matching oils. By removing the substrate contribution with properly chosen oil, we can extract the excitonic decay rates including the quantum mechanical dephasing rate. The results provide valuable guidance for the engineering of exciton line shapes in layered nanophotonic systems.</p

Proteorhodopsin overproduction enhances the long-term viability of Escherichia coli

Genes encoding the photoreactive protein proteorhodopsin (PR) have been found in a wide range of marine bacterial species, reflecting the significant contribution that PR makes to energy flux and carbon cycling in ocean ecosystems. PR can also confer advantages to enhance the ability of marine bacteria to survive periods of starvation. Here, we investigate the effect of heterologously produced PR on the viability of Escherichia coli. Quantitative mass spectrometry shows that E. coli, exogenously supplied with the retinal cofactor, assembles as many as 187,000 holo-PR molecules per cell, accounting for approximately 47% of the membrane area; even cells with no retinal synthesize ∼148,000 apo-PR molecules per cell. We show that populations of E. coli cells containing PR exhibit significantly extended viability over many weeks, and we use single-cell Raman spectroscopy (SCRS) to detect holo-PR in 9-month-old cells. SCRS shows that such cells, even incubated in the dark and therefore with inactive PR, maintain cellular levels of DNA and RNA and avoid deterioration of the cytoplasmic membrane, a likely basis for extended viability. The substantial proportion of the E. coli membrane required to accommodate high levels of PR likely fosters extensive intermolecular contacts, suggested to physically stabilize the cell membrane and impart a long-term benefit manifested as extended viability in the dark. We propose that marine bacteria could benefit similarly from a high PR content, with a stabilized cell membrane extending survival when those bacteria experience periods of severe nutrient or light limitation in the oceans

Loss-attentional physics-informed neural networks

Physics-informed neural networks (PINNs) have emerged as a significant endeavour in recent years to utilize artificial intelligence technology for solving various partial differential equations (PDEs). Nevertheless, the vanilla PINN model structure encounters challenges in accurately approximating solutions at hard-to-fit regions with, for instance, “stiffness” points characterized by fast-paced alterations in timescale. To this end, we introduce a novel model architecture based on PINN, named loss-attentional physics-informed neural networks (LA-PINN), which equips each loss component with an independent loss-attentional network (LAN). Feeding the squared errors (SE) on every training point into LAN as the input, the attentional function is then built by each LAN and provides different weights to diverse point SEs. A point error-based weighting approach that utilizes the adversarial training between multiple networks in the LA-PINN model is proposed to dynamically update weights of SE during every training epoch. Additionally, the weighting mechanism of LA-PINN is analysed and also be validated by performing several numerical experiments. The experimental results indicate that the proposed method displays superior predictive performance compared to the vanilla PINN and holds a swift convergence characteristic. Moreover, it can advance the convergence of those hard-to-fit points by progressively increasing the growth rates of both the weight and the update gradient for point error

Quasi-Periodic Releases of Streamer Blobs and Velocity Variability of the Slow Solar Wind near the Sun

We search for persistent and quasi-periodic release events of streamer blobs during 2007 with the Large Angle Spectrometric Coronagraph on the \textit{Solar and Heliospheric Observatory} and assess the velocity of the slow solar wind along the plasma sheet above the corresponding streamer by measuring the dynamic parameters of blobs. We find 10 quasi-periodic release events of streamer blobs lasting for three to four days. In each day of these events, we observe three-five blobs. The results are in line with previous studies using data observed near the last solar minimum. Using the measured blob velocity as a proxy for that of the mean flow, we suggest that the velocity of the background slow solar wind near the Sun can vary significantly within a few hours. This provides an observational manifestation of the large velocity variability of the slow solar wind near the Sun.Comment: 14 pages, 5 figures, accepted by Soalr Physic

A Statistical Study on the Morphology of Rays and Dynamics of Blobs in the Wake of Coronal Mass Ejections

In this paper, with a survey through the Large Angle and Spectrometric Coronagraph (LASCO) data from 1996 to 2009, we present 11 events with plasma blobs flowing outwards sequentially along a bright coronal ray in the wake of a coronal mass ejection. The ray is believed to be associated with the current sheet structure that formed as a result of solar eruption, and the blobs are products of magnetic reconnection occurring along the current sheet. The ray morphology and blob dynamics are investigated statistically. It is found that the apparent angular widths of the rays at a fixed time vary in a range of 2.1-6.6 (2.0-4.4) degrees with an average of 3.5 (2.9) degrees at 3 (4) Rs, respectively, and the observed durations of the events vary from 12 h to a few days with an average of 27 h. It is also found, based on the analysis of blob motions, that 58% (26) of the blobs were accelerated, 20% (9) were decelerated, and 22% (10) moved with a nearly-constant speed. Comparing the dynamics of our blobs and those that are observed above the tip of a helmet streamer, we find that the speeds and accelerations of the blobs in these two cases differ significantly. It is suggested that these differences of the blob dynamics stem from the associated magnetic reconnection involving different magnetic field configurations and triggering processes.Comment: 12 pages, 6 figures, accepted by Solar Physic

A Purcell-enabled monolayer semiconductor free-space optical modulator

Dephasing and non-radiative decay processes limit the performance of a wide variety of quantum devices at room temperature. Here we illustrate a general pathway to notably reduce the detrimental impact of these undesired effects through photonic design of the device electrodes. Our design facilitates a large Purcell enhancement that speeds up competing, desired radiative decay while also enabling convenient electrical gating and charge injection functions. We demonstrate the concept with a free-space optical modulator based on an atomically thin semiconductor. By engineering the plasmonic response of a nanopatterned silver gate pad, we successfully enhance the radiative decay rate of excitons in a tungsten disulfide monolayer by one order of magnitude to create record-high modulation efficiencies for this class of materials at room temperature. We experimentally observe a 10% reflectance change as well as 3 dB signal modulation, corresponding to a 20-fold enhancement compared with modulation using a suspended monolayer in vacuum. We also illustrate how dynamic control of light fields can be achieved with designer surface patterns. This research highlights the benefits of applying radiative decay engineering as a powerful tool in creating high-performance devices that complements substantial efforts to improve the quality of materials.</p