Bacteria-Responsive Self-Assembly of Antimicrobial Peptide Nanonets for Trap-and-Kill of Antibiotic-Resistant Strains

Bacterial trapping using nanonets is a ubiquitous immune defense mechanism against infectious microbes. These nanonets can entrap microbial cells, effectively arresting their dissemination and rendering them more vulnerable to locally secreted microbicides. Inspired by this evolutionarily conserved anti-infective strategy, a series of 15 to 16 residue-long synthetic β-hairpin peptides is herein constructed with the ability to self-assemble into nanonets in response to the presence of bacteria, enabling spatiotemporal control over microbial killing. Using amyloid-specific K114 assay and confocal microscopy, the membrane components lipoteichoic acid and lipopolysaccharide are shown to play a major role in determining the amyloid-nucleating capacity as triggered by Gram-positive and Gram-negative bacteria respectively. These nanonets displayed both trapping and killing functionalities, hence offering a direct improvement from the trap-only biomimetics in literature. By substituting a single turn residue of the non-amyloidogenic BTT1 peptide, the nanonet-forming BTT1-3A analog is produced with comparable antimicrobial potency. With the same sequence manipulation approach, BTT2-4A analog modified from BTT2 peptide showed improved antimicrobial potency against colistin-resistant clinical isolates. The peptide nanonets also demonstrated robust stability against proteolytic degradation, and promising in vivo efficacy and biosafety profile. Overall, these bacteria-responsive peptide nanonets are promising clinical anti-infective alternatives for circumventing antibiotic resistance.     

Chryseobacterium meningosepticum in a parapneumonic effusion in a chronic kidney disease patient on hemodialysis

Chryseobacterium meningosepticum is an uncommon human pathogen, which is an inhabitant of soil and water. It should be included in the list of suspected nosocomial infections, especially in patients with immunocompromised status. C. meningosepticum infections are not common but are clinically important because the organism is naturally resistant to multiple antibiotics. We report a case where the bacterium was isolated from the pleural fluid from a chronic kidney disease patient on hemodialysis, who developed pneumonia with complicated parapneumonic effusion. To the best of our knowedge, this is the first case where C. meningosepticum is isolated from the pleural effusion, from India.     

Textural and microstructural developments during fabrication of Zr-2.5Nb pressure tubes

Zr-2.5wt%Nb pressure tubes, as used in the Indian pressurized heavy water reactors (PHWR), are fabricated through a combination of hot extrusion followed by two stages of cold pilgering and annealing. The present study makes an effort to systematically characterize the textural changes during the fabrication stages. The starting single-phase hcp martensitic structure was textured to start with and it also went through strong texture developments during hot extrusion. First and especially the second pilgering modified the texture. Such modifications were related to local discontinuity of the softer second phase, as an apparent continuity restricted lattice rotation in the primary hcp phase. Annealing caused discontinuity or spherodization of the bcc phase, but did not create recrystallization in the hcp matrix. The combination of two pilgering plus annealing operations, though the latter did not cause noticeable texture changes, however, reverted the final texture close to the parent hot-extruded texture.     

Effect of hinokitiol impregnated sheets on shelf life and quality of “KEK‐1” tomatoes during storage

Hinokitiol (β‐thujaplicin, volatile oil extracted from the wood of Hiba arborvitae [Thujopsis dolabrata var. hondae], cypress family) is a natural preservative, antimicrobial, and chelating agent, used to prevent decay and extend the shelf life of fruits and vegetables. In the present study, we used nonwoven rayon sheets impregnated with hinokitiol to conduct packaging studies. Mature green tomatoes var. “KEK‐1” were packaged under three packaging conditions, ie, modified atmosphere packaging (MAP), MAP + hinokitiol (MH), and perforated film package (as control), and their quality attributes were compared during storage. The packaging materials used were low‐density polyethylene (LDPE) film (40 μm) and fresh sheets of nonwoven rayon impregnated with hinokitiol. O₂ in the MAP packaged tomatoes were retained throughout the storage period (3% to 5% O₂). Results showed that MH had slightly improved quality attributes throughout the storage period when compared with MAP alone. Expression levels of LeACS, LeADH, and LeTBG4 genes were higher in 5 and 9 days of control when compared with MAP and MH. “KEK‐1” tomatoes had longer shelf life under MAP and MH packaging and maintained the quality at 15°C. Hence, the effect of the MAP with bioactive packaging treatments could be effective in the future application for the extension of shelf life and quality of fruits and vegetables.     

High Performance GCM Architecture for the Security of High Speed Network

Advanced Encryption Standard (AES) is an effective cryptography algorithm for providing the better data communication since it guaranties high security. The Galois/Counter Mode (AES-GCM) has been integrated in various security constrained applications because it provides both authentication and confidentiality. AES algorithm helps to provide data confidentiality while authentication is provided by a universal GHASH function. Since most of existing GCM architectures concentrated on power and area reduction but an compact and efficient hardware architecture should also be considered. In this paper, high-performance architecture for GCM is proposed and its implementation is described. In order to achieve higher operating frequency and throughput, pipelined S-boxes are used in AES algorithm. For a GCM realization of AES, a high-speed, high-throughput, parallel architecture is proposed. Experimental results proves that the performance of the proposed work is around 17% higher than the existing architecture with 3 Gb/s throughput using TSMC 45-nm CMOS technology.     

Monthly flow forecast for Mississippi River basin using artificial neural networks

Long-term monthly flow forecasts are essential for decision making in a river basin system. Many studies have already been reported on monthly as well as seasonal forecast using artificial neural networks (ANNs). This study demonstrates that monthly forecasts can be significantly improved if the input variables in ANN models are chosen with due consideration, even if number of training patterns are less. Monthly forecast models up to 12-month lead-time have been developed for Mississippi River in USA. It is seen that direct forecast with only antecedent flows as inputs does not improve the result. It is better to develop individual models for each month separately with information from previous years for the same month. Further, the forecast is found to significantly improve if the difference in predicted and actual flows is also included as one of the input variables (i.e. error updating), particularly where there is a clearly observed pattern in the historical information.     

Investigation of the reaction impurities associated with methylamphetamine synthesized using the Nagai method

The synthesis of methylamphetamine hydrochloride from l-ephedrine or d-pseudoephedrine hydrochloride via reduction with hydriodic acid and red phosphorus was investigated. Eighteen batches of methylamphetamine hydrochloride were synthesized in six replicate batches using three different reaction times. This allowed the investigation of the variation of impurities in the final product with reaction time. The results obtained have resolved previously conflicting impurity profile data reported in the literature for this synthesis route. The impurity profile was shown to change with reaction time, and all previously reported impurity components were identified but not in all batches. Additionally, 20 batches of methylamphetamine hydrochloride were synthesized from either from l-ephedrine or d-pseudoephedrine hydrochloride in reactions which were allowed to proceed for 24 h. The impurities present in the resulting batches were investigated, and route-specific impurities present in all batches were identified. Batch-to-batch fluctuations in the resultant chromatographic impurity profile, despite careful synthetic monitoring and control, were also noted.     

Perpendicular magnetization in self-assembled films of citrate-capped gamma-Fe2O3 nanocrystals on Si(100) surfaces

gamma-Fe2O3 nanocrystals capped with citrate and octylamine have been chemically prepared. The octylamine-capped nanocrystals exhibit a tendency to form ordered lattices. Films of nanocrystals of varying thickness (454, 720, and 1400 microg/cm2 in the case of citrate-capped nanocrystals and 300 microg/cm2 in the case of octylamine-capped nanocrystals) have been prepared on Si(100) substrates by drop casting and have been characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. Magnetic measurements have been carried out on the films as well as on nanocrystal powders. The films of citrate-capped gamma-Fe2O3 nanocrystals exhibit enhanced perpendicular magnetization, with the anisotropy depending on the film thickness.