Pughmichelsen2290

Resistance to last-resort carbapenem antibiotics is an increasing threat to human health, as it critically limits therapeutic options. Metallo-β-lactamases (MBLs) are the largest family of carbapenemases, enzymes that inactivate these drugs. Among MBLs, New Delhi metallo-β-lactamase 1 (NDM-1) has experienced the fastest and largest worldwide dissemination. This success has been attributed to the fact that NDM-1 is a lipidated protein anchored to the outer membrane of bacteria, while all other MBLs are soluble periplasmic enzymes. By means of a combined experimental and computational approach, we show that NDM-1 interacts with the surface of bacterial membranes in a stable, defined conformation, in which the active site is not occluded by the bilayer. Although the lipidation is required for a long-lasting interaction, the globular domain of NDM-1 is tuned to interact specifically with the outer bacterial membrane. In contrast, this affinity is not observed for VIM-2, a natively soluble MBL. Finally, we identify key residues involved in the membrane interaction with NDM-1, which constitute potential targets for developing therapeutic strategies able to combat resistance granted by this enzyme.ConspectusAluminum in its nanostructured form is generating increasing interest because of its light-harvesting properties, achieved by excitation of its localized surface plasmon resonance. Compared to traditional plasmonic materials, the coinage metals Au and Ag, Al is far more earth-abundant and, therefore, more suitable for large-area applications or where cost may be an important factor. Its optical properties are far more flexible than either Au or Ag, supporting plasmon resonances that range from UV wavelengths, through the visible regime, and into the infrared region of the spectrum. However, the chemical synthesis of Al nanocrystals (NCs) of controlled size and shape has historically lagged far behind that of Au and Ag. This is partially due to the high reactivity of Al precursors, which react readily with O2, H2O, and many reagents used in traditional NC syntheses. The first chemical synthesis of Al NCs was demonstrated by Haber and Buhro in 1998, decomposing AlH3 using titanium isopropoxide (TIP), and low-cost plasmonic nanomaterial complementary to Au and Ag.The modulation of conformational flexibility in antimicrobial peptides (AMPs) has been investigated as a strategy to improve their efficacy against bacterial pathogens while reducing their toxicity. Here, we synthesized a library of helicity-modulated antimicrobial peptoids by the position-specific incorporation of helix-inducing monomers. The peptoids displayed minimal variations in hydrophobicity, which permitted the specific assessment of the effect of conformational differences on antimicrobial activity and selectivity. Among the moderately helical peptoids, the most dramatic increase in selectivity was observed in peptoid 17, providing more than a 20-fold increase compared to fully helical peptoid 1. Peptoid 17 had potent broad-spectrum antimicrobial activity that included clinically isolated multi-drug-resistant pathogens. Compared to pexiganan AMP, 17 showed superior metabolic stability, which could potentially reduce the dosage needed, alleviating toxicity. Dye-uptake assays and high-resolution imaging revealed that the antimicrobial activity of 17 was, as with many AMPs, mainly due to membrane disruption. However, the high selectivity of 17 reflected its unique conformational characteristics, with differential interactions between bacterial and erythrocyte membranes. Our results suggest a way to distinguish different membrane compositions solely by helicity modulation, thereby improving the selectivity toward bacterial cells with the maintenance of potent and broad-spectrum activity.Homogeneous ternary oxides of silicon-, niobium-, and molybdenum-aluminate were deposited by plasma-enhanced ALD using sequential metal precursor pulses prior to the oxidation step, to reduce interfacial defects usually observed in nanolaminate growth. The growth kinetics can be understood in terms of competitive adsorption. Trimethyl aluminum (TMA) is strongly chemisorbed to the growth surface and does not permit coadsorption of any of the other precursors; when we lead with a TMA pulse, the resulting film is always Al2O3. When we lead with the Si or Nb precursors, the growth surface is partially saturated, but open sites are available for TMA coadsorption. The Mo precursor is weakly chemisorbed and is largely displaced by a subsequent TMA dose. As compared to nanolaminate films of the constituent binary oxides, the interface state density is reduced by up to a factor of 5.NH4+ preintercalated V2O5·nH2O nanobelts with a large interlayer distance of 10.9 Å were prepared by the hydrothermal method. The material showed a large specific capacity of 391 mA·h·g-1 at the 500 mA·g-1 current density in aqueous rechargeable zinc batteries. In operando synchrotron X-ray diffraction demonstrated that the material experienced reversible solid-solution reaction and two-phase transition during charge-discharge cycling, accompanied by the reversible formation/decomposition of a ZnSO4Zn3(OH)6·5H2O byproduct. In operando X-ray absorption spectroscopy confirmed the reversible reduction/oxidation of V, together with small changes in the VO6 local structure. The formation of byproduct was attributed to the dehydration of [Zn(H2O)6]2+, which concurrently improved the desolvation of [Zn(H2O)6]2+ into Zn2+. Bond valence sum map analysis and electrochemical impedance spectroscopy demonstrated that the byproduct improved the charge transfer kinetics of the electrode. Cyclic voltammetry and galvanostatic intermittent titration technique showed that the electrode reaction was dominated by ionic intercalation where the discharge capacity in the voltage window of 1.4-0.85 V was attributed to the intercalation of [Zn(H2O)6]2+, followed by the intercalation of Zn2+ at 0.85-0.4 V.To respond to global challenges of environmental contaminations, pursue more advanced material technologies, and achieve novel biomedical therapies, a variety of plasmas have been applied to wastewater and food processing, biomaterial treatments, and plasma-liquid ignitions. As these applications highly depend on the plasma-liquid interactions, researchers are now focusing on the physical and chemical reactions on the plasma-liquid interface. With massive publications reporting the molecular transfers, chemical pathways, and their effects on plasma treatments, this work provides a new point of view that the plasma-liquid interface can be manipulated by the chamber structure. In the experiment, plasma jet expansion in water is recorded in a cylinder chamber and a stepped-wall one. Data collected from the images show that the stepped-wall structure results in a shorter axial interface propagation, a small volume, more symmetry for the plasma jet, and more stability for the interface. To discover the physical mechanism behind these phenomena, we derived the momentum and energy equations for the plasma-liquid interface during its propagation. Those equations reveal how the stepped-wall structure can be used to manipulate the interface behaviors. Along with our experimental and theoretical investigation of the plasma-liquid interface, such information also sheds light on how the chamber wall structure can be used to manipulate the interface chemical reaction rates, stability, and expansion rate. This work is thus a basis of the future optimization for plasma-liquid treatments and ignitions which will be equipped with a flexible wall controlled by artificial intelligence to automatically achieve a variety of plasma treatment requirements.Interface is the Achilles' heel in flexible electronics, where slipping, delamination, or cracking resulting from the intrinsic mechanical property mismatch of different materials might fail the device or cause degradation. Robust connections with strong interfacial strength and low interfacial impedance are highly desired in all kinds of flexible devices, especially when they require stretchability. Here, a new strategy of employing homogeneity is proposed to facilely achieve robust connection without introducing a third-party interlayer. The key to this strategy is implementing different functions in the same component materials, and in this work, this strategy is demonstrated by exploring the uniformity of carbon nanotube (CNT) in thermoplastic polyurethane (TPU) elastomer. Tuning the uniformity of CNT in TPU elastomer, two kinds of CNT-TPU composites (CTCs) are fabricated. check details They present contrasting properties of conductivity (281 folds), Young's modulus (7.1 folds), and strain sensitivity (15.7 folds) with the same weight fraction of CNT (15 wt %), and thus they can respectively act as strain sensor and interconnector in all-CNT-based stretchable strain monitoring electronics. The interlocking effect caused by spontaneous entanglement of surface polymer chains and the reconstruction of percolation network at the interface during drying confer the connection with robustness. link2 The practical value of this strategy has been exemplified by the fabrication of a robust epidermis device via additive manufacturing. link3 This epidermis device is patterned in a fractal motif for conformal contact and can sensitively monitor body motions and radial artery pulse.Understanding and controlling charge transfer through molecular nanostructures at interfaces is of paramount importance, particularly for electronic devices but also for contact electrification or in bioelectronics. We investigate the influence of intercalation and exchange of molecularly thin layers of small molecules (water, ethanol, 2-propanol, and acetone) on charge transfer at the well-defined interface between an insulator (muscovite mica) and a conductor (graphene). Raman spectroscopy is used to probe the charge carriers in graphene. While a molecular layer of water blocks charge transfer between mica and graphene, a layer of the organic molecules allows for it. The exchange of molecular water layers with ethanol layers switches the charge transfer very efficiently from off to on and back. We propose a charge transfer model between occupied mica trap states and electronic states of graphene, offset by the electrostatic potentials produced by the molecular dipole layers, as supported by molecular dynamics simulations. Our work demonstrates how intercalation of molecules of volatile liquids can reversibly affect charge transfer at interfaces. This implies its strong impact on the function of hybrid inorganic-organic electronic devices in different ambients and potential applications, including sensors and actuators.Gram-negative bacteria have developed several nanomachine channels known as type II, III, IV and VI secretion systems that enable export of effector proteins/toxins from the cytosol across the outer membrane to target host cells. Protein secretion systems are critical to bacterial virulence and interactions with other organisms. Aeromonas utilize various secretion machines e.g. two-step T2SS, a Sec-dependent system as well as one-step, Sec-independent T3SS and T6SS systems to transport effector proteins/toxins and virulence factors. Type III secretion system (T3SS) is considered the dominant virulence system in Aeromonas. The activity of bacterial T3SS effector proteins most often leads to disorders in signalling pathways and reorganization of the cell cytoskeleton. There are also scientific reports on the pathogenicity mechanism associated with host cell apopotosis/pyroptosis resulting from secretion of a cytotoxic enterotoxin, i.e. the Act protein, by the T2SS secretion system and an effector protein Hcp by the T6SS system.