N-methyl Benzimidazole Tethered Cholic Acid Amphiphiles Can Eradicate S. aureus-Mediated Biofilms and Wound Infections

Infections associated with Gram-positive bacteria like S. aureus pose a major threat as these bacteria can develop resistance and thereby limit the applications of antibiotics. Therefore, there is a need for new antibacterials to mitigate these infections. Bacterial membranes present an attractive therapeutic target as these membranes are anionic in nature and have a low chance of developing modifications in their physicochemical features. Antimicrobial peptides (AMPs) can disrupt the microbial membranes via electrostatic interactions, but the poor stability of AMPs halts their clinical translation. Here, we present the synthesis of eight N-methyl benzimidazole substituted cholic acid amphiphiles as antibacterial agents. We screened these novel heterocyclic cholic acid amphiphiles against different pathogens. Among the series, CABI-6 outperformed the other amphiphiles in terms of bactericidal activity against S. aureus. The membrane disruptive property of CABI-6 using a fluorescence-based assay has also been investigated, and it was inferred that CABI-6 can enhance the production of reactive oxygen species. We further demonstrated that CABI-6 can clear the pre-formed biofilms and can mitigate wound infection in murine models.     

MPI-HMMER-Boost: Distributed FPGA Acceleration

HMMER, based on the profile Hidden Markov Model (HMM) is one of the most widely used sequence database searching tools, allowing researchers to compare HMMs to sequence databases or sequences to HMM databases. Such searches often take many hours and consume a great number of CPU cycles on modern computers. We present a cluster-enabled hardware/software-accelerated implementation of the HMMER search tool hmmsearch. Our results show that combining the parallel efficiency of a cluster with one or more high-speed hardware accelerators (FPGAs) can significantly improve performance for even the most time consuming searches, often reducing search times from several hours to minutes.

Synthesis, characterization and photovoltaic properties of poly(thiophenevinylene-alt-benzobisoxazole)s

Herein we report the synthesis of two solution processible, conjugated polymers containing the benzobisoxazole moiety. The polymers were characterized using (1)H NMR, UV-Vis and fluorescence spectroscopy. Thermal gravimetric analysis shows that the polymers do not exhibit significant weight loss until approximately 300 °C under nitrogen. Cyclic voltammetry shows that the polymers have reversible reduction waves with estimated LUMO levels at -3.02 and -3.10 eV relative to vacuum and optical bandgaps of 2.04-2.17 eV. Devices based on blends of the copolymers and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) exhibited modest power conversion efficiencies. Theoretical models reveal that there is poor electron delocalization along the polymer backbone, leading to poor performance. However, the energy levels of these polymers indicate that the incorporation of benzobisoxazoles into the polymer backbone is a promising strategy for the synthesis of new materials.     

Physicochemical and Transmission Electron Micrograph (TEM) Studies of Few Carbohydrate Molecules with Aqueous and Aqueous Geraniol Oil Mixtures

Densities (ρ/10³ kg m^?3), viscosities (η/0.1 N s m^?2) and surface tension (γ/mN m^?1) of aqueous 0.005 to 0.02 mol L^?1 mannitol, glucose and fructose at an interval of 0.005 mol L^?1 and the 0.02, 0.025, and 0.03 v% aqueous geraniol oil were studied. The similar carbohydrates were also studied with 0.025 v% aqueous geraniol. TEM were recorded for sizes of molecules for analysis of probable energy consumption in flow through a capillary of Survismeter, like blood capillaries. The ρ values were used for viscosities (η) and surface tensions (γ). The η were fitted with extended Jones-Dole equation for B/L mol^?1 and D/(L mol^?1)² coefficients to explain carbohydrate-geraniol interactions. The B and γ values illustrate structural behavior of carbohydrates irrespective of the compositions. These data analyze hydrophilic and hydrophobic interactions of geraniol and carbohydrates where electron micrographs depict shortening of sizes and intermolecular distances with geraniol. The size with and without geraniol remained from 0.019–0.035 nm and 0.016–0.038 nm, respectively. The geraniol increased the densities and decreased the surface tension to almost one half of the binary systems with an effective intermixing.     

Conformationally constrained aliphatic-aromatic amino-acid-conjugated hybrid foldamers with periodic beta-turn motifs

In this note, we describe the design, synthesis, and structural studies of novel hybrid foldamers derived from Aib-Pro-Adb building blocks that display repeat beta-turn structure motif. The foldamer having a conformationally constrained aliphatic-aromatic amino acid conjugate adopts a well-defined, compact, three-dimensional structure, governed by a combined conformational restriction imposed by the individual amino acids with which it is made of. Conformational investigations by single-crystal X-ray and solution-state NMR studies were undertaken to investigate the conformational preference of these foldamers with a hetero-backbone. Our findings suggest that constrained aliphatic-aromatic amino acid conjugates would offer new avenues for the de novo design of hybrid foldamers with distinctive structural architectures.     

BPB dye confined growth of surfactant-assisted mesostructured silica matrix fiber optic sensing tracers

Thermally stable surfactant modified silica nano-matrix is synthesized by the sol–gel method at low temperature. The surfactant such as cetyltrimethylammonium bromide (CTAB) assisted silica matrix is encapsulated with bromophenol blue (BPB) for sensing activities. Prepared nano-matrix consists of numerous morphological structures such as a pseudo-spherical, hierarchal and islands. The morphology of mesoporous high surface area matrices is strongly affected by CTAB, BPB dye and the aging conditions that determine the transformation from disordered silica nano-matrix morphologies to ordered encapsulated structures. Furthermore, smooth surface matrices with low surface roughness 1.2 nm, low refractive index 1.36, large pores and small dimensions of heteroatoms contribute to the stable sensing activities. The response of coated fiber optic is determined at dynamic pH range 1–12. The prepared sensor has reversibility/repeatability, stability and fast response time of approximately 0.25 s in basic media. The accuracy of sensing device measurements in household ammonia solution and the borax solution suggested that prepared device has clear potential for daily life usage.     

Purification,growth and ESR studies of sodium nitrate

Single crystals of sodium nitrate have been purified and grown using zone-refining system fabricated in our laboratory. Laue photographs were employed to check the crystallinity. X-ray irradiated crystals have been studied by electron spin resonance.     

Laser-induced phase transitions in PbI2

Pure crystals of PbI₂ have been grown using zone-refining system. The structural phase transition 12 R → 2 H has been observed when exposed to ruby laser light. The results have been explained on the basis of structural considerations of PbI₂ and compared with the earlier existing findings in literature.     

Nonlinear Luminescence in CdI2 under Pulsed Laser Excitation

Cadmium iodide has been studied from the point of view of nonlinear processes by experiments of optical amplification under two photon excitation. The two photon absorption (2PA) coefficient is determined by nonlinear transmittance technique. By means of two and three photon comparative luminescence measurements carried out using a ruby and neodymium laser, the three photon absorption (3PA) coefficient is determined. The experimental values of the absorption coefficients are compared with the predictions of the existing theories.