scholarly journals Mono-6-Substituted Cyclodextrins—Synthesis and Applications

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5065
Author(s):  
Petr Kasal ◽  
Jindřich Jindřich
Keyword(s):  
Covalent Binding ◽  
Synthetic Methods ◽  
Optimal Solutions ◽  
Glucose Unit ◽  
Intended Purpose ◽  
Wide Range ◽  
Different Types ◽  
The Common ◽  
Common Problems ◽  
Number Of Publications

Cyclodextrins are well known supramolecular hosts used in a wide range of applications. Monosubstitution of native cyclodextrins in the position C-6 of a glucose unit represents the simplest method how to achieve covalent binding of a well-defined host unit into the more complicated systems. These derivatives are relatively easy to prepare; that is why the number of publications describing their preparations exceeds 1400, and the reported synthetic methods are often very similar. Nevertheless, it might be very demanding to decide which of the published methods is the best one for the intended purpose. In the review, we aim to present only the most useful and well-described methods for preparing different types of mono-6-substituted derivatives. We also discuss the common problems encountered during their syntheses and suggest their optimal solutions.

scholarly journals A comprehensive study of distributed Denial-of-Service attack with the detection techniques

2020 ◽  
Vol 10 (4) ◽  
pp. 3685
Author(s):  
H. H. Ibrahim ◽  
A. E. Hamzah ◽  
H. A. Saeed ◽  
H. H. Qasim ◽  
O. S. Hamed ◽  
...  
Keyword(s):  
Denial Of Service ◽  
Dos Attacks ◽  
Huge Amount ◽  
Detection Techniques ◽  
Denial Of Service Attack ◽  
Wide Range ◽  
Different Types ◽  
Service Attack ◽  
The Common ◽  
Comprehensive Study

With the dramatic evolution in networks nowadays, an equivalent growth of challenges has been depicted toward implementing and deployment of such networks. One of the serious challenges is the security where wide range of attacks would threat these networks. Denial-of-Service (DoS) is one of the common attacks that targets several types of networks in which a huge amount of information is being flooded into a specific server for the purpose of turning of such server. Many research studies have examined the simulation of networks in order to observe the behavior of DoS. However, the variety of its types hinders the process of configuring the DoS attacks. In particular, the Distributed DoS (DDoS) is considered to be the most challenging threat to various networks. Hence, this paper aims to accommodate a comprehensive simulation in order to figure out and detect DDoS attacks. Using the well-known simulator technique of NS-2, the experiments showed that different types of DDoS have been characterized, examined and detected. This implies the efficacy of the comprehensive simulation proposed by this study.

Synthetic Methods and Pharmacological Potential of Different Oxazine Analogs

2021 ◽  
Vol 18 ◽  
Author(s):  
Mohammad Asif ◽  
Mohd. Imran
Keyword(s):  
Organic Chemistry ◽  
Drug Resistance ◽  
Sodium Hydroxide ◽  
Crucial Role ◽  
Heterocyclic Compounds ◽  
Biological Activities ◽  
Synthetic Methods ◽  
Wide Range ◽  
Different Types ◽  
Pharmacological Potential

: Oxazine analog is a vital class of heterocyclic compounds and has attracted synthetic interest owing to their wide range of biological activities. Oxazine analogs are valuable in medicinal organic chemistry and exhibited different varieties of biological activities such as antimicrobial, anticancer, antimalarial, antitubercular, sedative, anticonvulsant, analgesic, anti-inflammatory, antipyretic, etc. Oxazine can be derived from benzene by appropriate substitution of carbon atoms of the ring by nitrogen and oxygen atoms. Nowadays, the development of drug resistance is a key problem, and to defeat this problem, it is crucial to synthesize novel compounds. So novel oxazine analogs may play a crucial role to overcome these problems. Oxazine analogs are prepared by reaction of chalcone derivatives with thiourea in the presence of alcohol and sodium hydroxide. The present aims of this review to give an outline of some different synthetic methods and different types of biological activities of oxazine analogs. We hope that this review will be motivating for researchers concerned with oxazine analogs.

Complete Equity and Trusts

2018 ◽  
Author(s):  
Richard Clements ◽  
Ademola Abass
Keyword(s):  
Subject Matter ◽  
Common Law ◽  
Wide Range ◽  
Specific Performance ◽  
Different Types ◽  
Complete Series ◽  
Explanatory Text ◽  
The Common ◽  
Primary Materials

Titles in the Complete series combine extracts from a wide range of primary materials with clear explanatory text to provide readers with a complete introductory resource.This book deals with the emergence of equity and how it differs from the common law. The trust concept is explained and the different types of trust that exist outlined. These include resulting, constructive, and charitable trusts. Trusts must obey certain basic rules such as legal formalities and the three certainties of intention, subject matter, and the need for a beneficiary. There are exceptions to these strict rules, such as proprietary estoppel and certain gifts made upon death, for example secret trusts and donatio mortis causa. The office of trustee is considered, including the methods of appointment; their powers of maintenance, advancement, variation, and investment; and the fiduciary nature of their office. Equitable remedies, such as injunctions, specific performance, and tracing are included. The use of constructive trusts in cohabitation disputes is analysed.

scholarly journals Human Uterine Biopsy: Research Value and Common Pitfalls

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Alison Maclean ◽  
Areege Kamal ◽  
Meera Adishesh ◽  
Rafah Alnafakh ◽  
Nicola Tempest ◽  
...  
Keyword(s):  
Current Understanding ◽  
Future Research ◽  
Human Uterus ◽  
Oncology Research ◽  
Human Fertility ◽  
Different Types ◽  
Health And Disease ◽  
The Common ◽  
Common Problems

The human uterus consists of the inner endometrium, the myometrium, and the outer serosa. Knowledge of the function of the uterus in health and disease is relevant to reproduction, fertility, embryology, gynaecology, endocrinology, and oncology. Research performed on uterine biopsies is essential to further the current understanding of human uterine biology. This brief review explores the value of the uterine biopsy in gynaecological and human fertility research and explores the common problems encountered when analysing data generated from different types of uterine biopsies, with the aim of improving the quality, reproducibility, and clinical translatability of future research.

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

2020 ◽  
Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer
Keyword(s):  
Wittig Reaction ◽  
Condensation Reaction ◽  
Synthetic Methods ◽  
Anthracene Derivative ◽  
Double Ring ◽  
Mild Conditions ◽  
Wide Range ◽  
Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

Small Molecule Permeation Across Membrane Channels: Chemical Modification to Quantify Transport Across OmpF

2018 ◽  
Author(s):  
Jiajun Wang ◽  
Jayesh Arun Bafna ◽  
Satya Prathyusha Bhamidimarri ◽  
Mathias Winterhalter
Keyword(s):  
Dwell Time ◽  
Covalent Binding ◽  
Channel Structure ◽  
Ion Current ◽  
E Coli ◽  
Current Fluctuation ◽  
Wide Range ◽  
Outer Membrane Channel ◽  
Biological Channels ◽  
Constriction Region

Biological channels facilitate the exchange of small molecules across membranes, but surprisingly there is a lack of general tools for the identification and quantification of transport (i.e., translocation and binding). Analyzing the ion current fluctuation of a typical channel with its constriction region in the middle does not allow a direct conclusion on successful transport. For this, we created an additional barrier acting as a molecular counter at the exit of the channel. To identify permeation, we mainly read the molecule residence time in the channel lumen as the indicator whether the molecule reached the exit of the channel. As an example, here we use the well-studied porin, OmpF, an outer membrane channel from <i>E. coli</i>. Inspection of the channel structure suggests that aspartic acid at position 181 is located below the constriction region (CR) and we subsequently mutated this residue to cysteine, where else cysteine free and functionalized it by covalent binding with 2-sulfonatoethyl methanethiosulfonate (MTSES) or the larger glutathione (GLT) blockers. Using the dwell time as the signal for transport, we found that both mono-arginine and tri-arginine permeation process is prolonged by 20% and 50% respectively through OmpF<sub>E181C</sub>MTSES, while the larger sized blocker modification OmpF<sub>E181C</sub>GLT drastically decreased the permeation of mono-arginine by 9-fold and even blocked the pathway of the tri-arginine. In case of the hepta-arginine as substrate, both chemical modifications led to an identical ‘blocked’ pattern observed by the dwell time of ion current fluctuation of the OmpF<sub>wt</sub>. As an instance for antibiotic permeation, we analyzed norfloxacin, a fluoroquinolone antimicrobial agent. The modulation of the interaction dwell time suggests possible successful permeation of norfloxacin across OmpF<sub>wt</sub>. This approach may discriminate blockages from translocation events for a wide range of substrates. A potential application could be screening for scaffolds to improve the permeability of antibiotics.

COPPER ALLOY No. 268

Alloy Digest ◽  
1976 ◽  
Vol 25 (2) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Copper Alloy ◽  
Cold Working ◽  
Heat Treating ◽  
Zinc Alloy ◽  
Good Resistance ◽  
Wide Range ◽  
Copper Zinc ◽  
The Common ◽  
Cold Worked

Abstract Copper Alloy No. 268 is a copper-zinc alloy with excellent cold-working properties and good resistance to corrosion. It can be cold worked by all the common fabrication processes and has a wide range of applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-306. Producer or source: Brass mills.

Applying Possessive pronoun in Writing Sentences: Exploring Students’ Ability and Problems in a Mixed Method Study

2019 ◽  
Vol 1 (3) ◽  
pp. 79-83
Author(s):  
Eka Utami Putri ◽  
Syahdan Syahdan
Keyword(s):  
Mixed Method ◽  
Simple Random Sampling ◽  
Average Score ◽  
Mixed Method Study ◽  
Z Score ◽  
Possessive Pronoun ◽  
Efl Students ◽  
The Common ◽  
Common Problems ◽  
Essay Test

The purpose of this research was to find out the students' ability in applying Possessive pronoun in writing sentences and the problems encounter it.  This mixed method study employs an explanatory design to reveals it. 53 students out of 105 students from1st semester EFL students from one reputable University in Pekanbaru, Indonesia, were invited to this study. These 53 students were selected using simple random sampling and enrolled for an essay test and interview to see the students' ability and explaining the problems. The data analysis using SPSS showed that the average score of students was 52.98. Meanwhile for the median is 48, the mode is 20. The score of Standard Deviation is 27.93, Variance is 780.25, and Range is 84.  Z-Score was found 41.5%, which is means higher than average and 58.5% while, students' ability was indicated below the average. It showed that the students were low ability in applying possessive pronoun in writing sentences. The study also found the common problems, i.e., (1) students still mixed up between possessive pronoun and possessive adjectives. (2) students used the wrong pattern in using a possessive pronoun. (3) students did not understand clearly about a possessive pronoun, (4) experiencing difficulties in learning possessive pronoun. 

Nanoparticles Functionalized with Venom-Derived Peptides and Toxins for Pharmaceutical Applications

2020 ◽  
Vol 21 (2) ◽  
pp. 97-109 ◽  
Author(s):  
Ana P. dos Santos ◽  
Tamara G. de Araújo ◽  
Gandhi Rádis-Baptista
Keyword(s):  
Oral Absorption ◽  
Current Data ◽  
Pharmacological Activities ◽  
Venom Peptides ◽  
Essential Components ◽  
Wide Range ◽  
Different Types ◽  
Direct Use ◽  
Animal Venoms ◽  
Pharmaceutical Biotechnology

Venom-derived peptides display diverse biological and pharmacological activities, making them useful in drug discovery platforms and for a wide range of applications in medicine and pharmaceutical biotechnology. Due to their target specificities, venom peptides have the potential to be developed into biopharmaceuticals to treat various health conditions such as diabetes mellitus, hypertension, and chronic pain. Despite the high potential for drug development, several limitations preclude the direct use of peptides as therapeutics and hamper the process of converting venom peptides into pharmaceuticals. These limitations include, for instance, chemical instability, poor oral absorption, short halflife, and off-target cytotoxicity. One strategy to overcome these disadvantages relies on the formulation of bioactive peptides with nanocarriers. A range of biocompatible materials are now available that can serve as nanocarriers and can improve the bioavailability of therapeutic and venom-derived peptides for clinical and diagnostic application. Examples of isolated venom peptides and crude animal venoms that have been encapsulated and formulated with different types of nanomaterials with promising results are increasingly reported. Based on the current data, a wealth of information can be collected regarding the utilization of nanocarriers to encapsulate venom peptides and render them bioavailable for pharmaceutical use. Overall, nanomaterials arise as essential components in the preparation of biopharmaceuticals that are based on biological and pharmacological active venom-derived peptides.

The chemistry of 4-(dicyanomethylene)-3-methyl-l-phenyl-2-pyrazoline-5- ones as a privileged scaffold in synthesis of heterocycles

2020 ◽  
Vol 17 ◽  
Author(s):  
Mohsen A.-M. Gomaa ◽  
Huda A. Ali
Keyword(s):  
Building Block ◽  
Heterocyclic Compounds ◽  
Recent Progress ◽  
Reaction Conditions ◽  
Azacrown Ethers ◽  
Wide Range ◽  
Privileged Scaffold ◽  
Number Of Publications ◽  
Near Future

Background : The reactivity of 4-(dicyanomethylene)-3-methyl-l-phenyl-2-pyrazoline-5-one DCNP 1 and its derivatives makes it valuable as a building block for the synthesis of heterocyclic compounds like pyrazolo-imidazoles, - thiazoles, spiropyridines, spiropyrroles, spiropyrans and others. As a number of publications have reported on the reactivity of DCNP and its derivatives, we compiled some features of this interesting molecule. Objective: This article aims to review the preparation of DCNP, its reactivity and application in heterocyclic and dyes synthesis. Conclusion: In this review we have provided an overview of recent progress in the chemistry of DCNP and its significance in synthesis of various classes of heterocyclic compounds and dyes. The unique reactivity of DCNP offers unprecedentedly mild reaction conditions for the generation of versatile cynomethylene dyes from a wide range of precursors including amines, α-aminocarboxylic acids, their esters, phenols, malononitriles and azacrown ethers. We anticipate that more innovative transformations involving DCNP will continue to emerge in the near future.

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