Synthesis and thermal properties of polyamide 6 (A)-polyimide (B) block copolymers of ABA type

Summary Polyimides (PI) having different molecular weights were prepared by condensation of oxydiphthalic anhydride with 9,9-bis-(4-aminophenyl)fluorene in nitrobenzene solution at 180°C. These polyimides carried two amino chain ends which allowed us to fix polycaprolactam chains (PA6) to obtain PA6-PI-PA6 type copolymers. The elemental analysis and infrared spectroscopic determination gave the proportion of PA6 (or PI) in the copolymers. The studies of thermal properties-DSC and TGA-allowed us to characterize the copolymers.     

A prototype of a superconducting magnet for a 170-GHz gyrotron

Within the framework of the “International Thermonuclear Experimental Reactor” (ITER) program, a prototype of a superconducting magnet for a 170-GHz gyrotron has been developed, manufactured, and tested. The operating induction value (7.1 T at the center of a 219-mm-diameter cold hole and 8.1 T on the winding) is reached at a current of 185.2 A. In the final version of the magnet, the required induction value was reached without aging. Special requirements are imposed on the distribution of the magnetic field along the axis, including an abrupt field decrease on both sides of the magnet. Axial forces are additionally taken by a special device. The magnet’s sections are wound with multifiber conductors based on niobium-tin and niobium-titanium alloys. Seventeen resistive shunts are provided for protecting sections during their transition to the normal state. The magnet is equipped with a device for removing a part of energy from the sections. Mechanical stresses in the magnet’s sections and the structure’s power elements have been measured during tests.     

Preparation of a sensor substrate using functionalized mesoporous silica on a gold film for surface plasmon resonance (SPR) spectroscopy

The use of surface plasmon resonance (SPR) spectroscopy has been applied to a wide variety of fields such as biosensors and surface analysis instruments. In general, a SPR substrate is prepared using self-assembled monolayer (SAM) method of organic molecules as receptor for the target on a layer of gold or silver. However, mesoporous inorganic materials such as SBA-15 have benefits as sensor substrate for SPR. Mesoporous silica has a large surface area which receptor molecule can be attached and has a rigid body which has an excellent stability in the extreme condition compared to organic sensing layer. We prepared an organic modified mesoporous silica and successfully immobilized it on a gold surface, in an attempt to use as a substrate for SPR spectroscopy. For the comparison of sensitivity of prepared substrate, Pt²⁺ detection was selected as a model system. Substrate prepared in this study exhibited the capability of selective sensing for Pt²⁺ ions.     

Cerium oxide-modified surfaces of several carbons as supports for a platinum-based anode electrode for methanol electro-oxidation

Catalyst composites based on Pt and CeO₂ on carbon for methanol oxidation were successively prepared for application in direct-methanol fuel cells (DMFCs). In this work, the catalyst was modified by decoration of CeO₂ onto several carbons, including carbon black (CB), carbon nanotubes (CNT), graphene oxide (GO), reduced graphene oxide (rGO) and mixed carbons, followed by the electrochemical deposition of Pt. The dispersal of CeO₂ and Pt nanoparticles onto the carbon surfaces was confirmed with a face-centred cubic structure. The use of single and mixed carbons takes admirable advantage of the coexisting CeO₂ and Pt nanoparticles, confirming the positive effect of various carbon structures for electrocatalytic enhancement towards methanol oxidation. The CeO₂ also improves the ability for CO oxidation, resulting in a reduction of CO poisoning. The outcomes show an enhancement of the activity and stability so that such alternative as-prepared materials can be introduced to improve the anodic oxidation in DMFCs.     

Antimicrobial and Amyloidogenic Activity of Peptides. Can Antimicrobial Peptides Be Used against SARS-CoV-2?

At present, much attention is paid to the use of antimicrobial peptides (AMPs) of natural and artificial origin to combat pathogens. AMPs have several points that determine their biological activity. We analyzed the structural properties of AMPs, as well as described their mechanism of action and impact on pathogenic bacteria and viruses. Recently published data on the development of new AMP drugs based on a combination of molecular design and genetic engineering approaches are presented. In this article, we have focused on information on the amyloidogenic properties of AMP. This review examines AMP development strategies from the perspective of the current high prevalence of antibiotic-resistant bacteria, and the potential prospects and challenges of using AMPs against infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).     

Rapid Total Synthesis of DARPin pE59 and Barnase

We report the convergent total synthesis of two proteins: DARPin pE59 and Bacillus amyloliquefaciens RNase (Barnase). Leveraging our recently developed fast‐flow peptide‐synthesis platform, we rapidly explored numerous conditions for the assembly of long polypeptides, and were able to mitigate common side reactions, including deletion and aspartimide products. We report general strategies for improving the synthetic quality of difficult peptide sequences with our system. High‐quality protein fragments produced under optimal synthetic conditions were subjected to convergent native chemical ligation, which afforded native full‐length proteins after a final desulfurization step. Both DARPin and Barnase were folded and found to be as active as their recombinant analogues.     

High J Pure Inversion Spectrum of ND3 in the v2 = 1 State

OBJECTIVE: The authors examined the efficacy of intramuscular flunitrazepam compared with intramuscular haloperidol for the immediate control of agitated or aggressive behavior in acutely psychotic patients. METHOD: Twenty-eight actively psychotic inpatients, aged 20-60 years, who were under treatment with neuroleptic agents were selected for the study. Each was randomly assigned on a double-blind basis to receive either 5 mg i.m. of haloperidol (N=13) or 1 mg i.m. of flunitrazepam (N=15) during an aggressive event. Verbal and physical aggression was measured over time with the Overt Aggression Scale. Patients were also rated with the Brief Psychiatric Rating Scale and the Clinical Global Impression scale. RESULTS: Both flunitrazepam and haloperidol exhibited acute antiaggressive activity. This beneficial effect, as assessed by the Overt Aggression Scale, was obtained within 30 minutes. CONCLUSIONS: Intramuscular flunitrazepam may serve as a convenient, rapid, safe, and effective adjunct to neuroleptics in reducing aggressive behavior in emergency psychiatric settings.     

The possibility of reducing thermal conductivity in alloys

Reduction of thermal conductivity in nickel—titanium alloys by doping with elements having the greatest effect on phonon and electron components of thermal conductivity is considered.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 2, pp. 278–281, August, 1985.     

Nonlinear Filter Model for Digital Imaging of Contrast Images

This paper describes a model of digital filtering of noisy contrasting images with minimum blur of brightness at the overfall boundary, which is based on smoothing out digital images with the help of the generalized method of least absolute values. The model requires variation of two parameters of the loss function as a function on the degree of contrast and noise level. The results are based on extensive computational experiments performed by the Monte Carlo statistical test method.