A Comprehensive Review on Therapeutic Potentials of Natural Cyclic Peptides

Cyclic peptides have emerged as a promising class of organic compounds that possess polypeptide chains with a cyclic ring structure. There is a circular sequence of bonds in which the ring structure is formed via linkage between one end of the peptide bond and the other end with an amide bond or any other chemically stable bonds like ether, thioether, lactone, and disulfide. Generally, the cyclic peptides are isolated from natural resources like invertebrate animals, micro-organisms of marine habitats, and higher plants. These cyclic peptides possess unique structures with diverse pharmacological activities. Now a day, cyclic peptides possess superior therapeutic value due to several reasons such as greater resistance to enzymatic degradation (in vivo) and higher bio-availability. Some of these cyclic peptides are rich in leucine, proline while some have other amino acids as their major constituents. Numerous novel cyclic peptides isolated from natural sources are successfully developed as bioactive products. Recently, cyclic peptides derived from natural resources have attracted attention for exploring their numerous beneficial effects. Moreover, it is reported that natural cyclic peptides exhibit various therapeutic activities like an anthelmintic, ACE inhibitor, anti-tumor, microtubule inhibitor, anti-fungal, anti-malarial, and platelet aggregation inhibiting activity. In this review, various cyclic peptides are reported with structures and biological activities that are isolated from various natural sources. The natural cyclic peptides possess a wide spectrum of biological activities and can become a drug of the future for replacing the existing drugs which develop resistance

Proposing a method to design secure digital signature scheme on the ring structure Zn

Abstract—In this paper, we propose a method to design signature scheme on ring structure with residual classes modulo composite. At the same time, we develop several new digital signature schemes that are more secure, with faster signature generation than ElGamal digital signature scheme and its variants. Furthermore, our proposed signature scheme has overcome some weaknesses of some published signature scheme of the same type, which are built on ring structure. Tóm tắt—Trong bài báo này, chúng tôi đề xuất một phương pháp thiết kế lược đồ chữ ký trên cấu trúc vành các lớp thặng dự theo modulo hợp số, đồng thời phát triển một số lược đồ chữ ký số mới an toàn hơn, tốc độ sinh chữ ký nhanh hơn so với lược đồ chữ ký số ElGamal cùng với những biến thể của nó. Hơn nữa, lược đồ chữ ký do chúng tôi đề xuất cũng khắc phục được một số nhược điểm của một số lược đồ chữ ký cùng loại, được xây dựng trên cấu trúc vành.

Molecules Containing Cyclobutyl Fragments as Therapeutic Tools: A Review on Cyclobutyl Drugs

In recent years, cyclobutyl has become ever more influential in the field of drug design. Its unique four-membered ring structure is not only a useful intermediate for the synthesis of biomedical candidate materials, but also an indispensable framework for drug design and application. According to the therapeutic field, cyclobutyl drugs are roughly divided into tumor and cancer drugs, nervous system drugs, analgesics, antiviral drugs, and gastrointestinal drugs. Among them, platinum-based anticancer drugs containing cyclobutyl fragments have achieved remarkable success in the treatment of cancer, bringing new hope for the development of more cyclobutyl drugs. This article provides details of the research progress of the structure types, structure-activity relationships, targets, and mechanisms of cyclobutyl drugs that have been on the market or are in the clinical stage, and provides ideas for the discovery and synthesis of novel cyclobutyl-containing drugs.

Designing of Microwave Metamaterial Biosensor for Water Pollution Monitoring

This paper focuses on developing a microwave metamaterial-based Microstrip Ring Resonator for water quality monitoring. Water pollution is increasing at an alarming rate, worsening pollution and destroying natural habitats. This paper aims to design a metamaterial-based resonator, analyse its performance with various biosamples, and then fabricate the designed product to validate the sensing performance. For this purpose, Computer Simulation Technology (CST) is used to design and simulate the proposed biosensor, with Rogers-RO3003 as the substrate material. In addition, for the proof of concept, different types of liquid materials under test were used in simulation and measurement. The procedures begin with the design and simulation of the MRR using CST, followed by the fabrication stage when the simulation produced the desired results, and finally, laboratory measurements for data collection. The sensing area of the microstrip ring resonator was observed through electric field distribution, where a gap was introduced in the ring structure. The results show that proposed structure of the resonator was able to distinguish different types of liquid that were placed in the sensing gap, by shifting the resonance frequency based on their dielectric constant. In summary, a new metamaterial-based microstrip ring resonator is produced to monitor liquid quality. The concept behind the paper was proven through simulations and experiments where it is suitable to be used as a sensing algorithm. In future work, this product could be used to monitor residue in our clean water, such as river, to minimise the polluted drinking water risk.

A Novel Polishing Process with Rigid-Flexible Composite Structure Plate and Its Performance in Polishing Sapphire Wafer

A novel flexible polishing process has been developed for sapphire wafer by using a polishing plate with rigid-flexible composite structure to satisfy the demands of excellent surface shape accuracy and high surface topography quality simultaneously. This new polishing plate was fabricated by alternately casting and curing the ring structure of soft and hard unsaturated resins. It is found that the overall stiffness of the polishing plate is improved due to the “hard support frame” of rigid-flexible polishing plate, as well as the ability of removal selectivity of the polishing plate is strengthened. The topography quality and shape accuracy of sapphire wafer polished by presented novel polishing process have been compared with those polished by conventional flexible polishing, respectively. Both experiment and simulation results are shown that the surface roughness and topographical variations of sapphire wafer polished by the novel rigid-flexible composite structure polishing plate have been greatly improved. Comparing with the conventional flexible polishing, the surface shape accuracy of the sapphire wafer polished by the presented novel polishing process can be improved by 54.1%.

Formation and Evolution of sp2 Hybrid Conjugate Structure of Polyacrylonitrile Precursor during Stabilization

The generated sp2 hybrid conjugate structure of a C atom, which resulted from the chemical reaction affected by temperature and time, is an effective six-membered ring planar structure of the final carbon fiber. This kind of hybrid conjugate structure determined the formation of the final structure and mechanical properties of carbon fiber. In this paper, the formation and evolution of sp2 hybrid conjugated structures of PAN precursor during thermal stabilization were investigated by Raman, UV-vis and 13C-NMR methods. The results indicated that with the increase of stabilization temperature, the degree of the sp2 hybrid conjugated structure of stabilized PAN fiber increases “linearly”, while the content of the sp2 hybrid carbon atoms increases with “S-type”. The final sp2 hybrid conjugated ring structure is mainly composed of single-ring, double-ring, triple-ring, and double-bond structures. Compared with the time factor, the temperature effect plays a decisive role in the formation of the sp2 hybrid conjugate structure.

Specific Design Solution for Covering Large Areas With Spatial Metal Truss

. The relevance of the research results given in the article lies in the need to apply new constructive solutions for large spaces. The purpose of this work is to search for new design solutions for covering large areas with spatial metal trusses. The problems of forming a computational spatial bar finite element model of a steel spatial truss of a dome-shaped radial-ring structure were solved. The calculation of the spatial system was carried out using the finite element method of current computer programs, new constructive solutions for spatial metal trusses were adopted. The stress-strain states of the model from a given load have been determined. The calculation of the spatial system was carried out using the finite element method of current computer programs, new constructive solutions for spatial metal trusses were adopted. The research results can be used in the formation of architectural and structural solutions of a building using a new structural arrangement of the elements of a spatial truss.