New approach to the use of 2-bromoethyl esters in peptide synthesis

1988 ◽  
Vol 53 (11) ◽  
pp. 2787-2790 ◽  
Author(s):  
M. Joaquina S. A. Amaral Trigo ◽  
M. Isabel A. Oliveira Santos
Keyword(s):  
Peptide Synthesis ◽  
Room Temperature ◽  
New Method ◽  
New Approach

The synthesis of six new fully protected dipeptides 2-bromoethyl esters and a new method for the removal of the C-protection by the action of the sulphide anion, at room temperature, are described.

A New Approach for the Analysis of Mixture Toxicity Data

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2345-2348 ◽  
Author(s):  
C. N. Haas
Keyword(s):  
Quantitative Analysis ◽  
Mixture Toxicity ◽  
New Method ◽  
Metal Exposure ◽  
Positive Interactions ◽  
Toxicity Data ◽  
Data Set ◽  
New Approach ◽  
Negative Interactions

A new method for the quantitative analysis of multiple toxicity data is described and illustrated using a data set on metal exposure to copepods. Positive interactions are observed for Ni-Pb and Pb-Cr, with weak negative interactions observed for Ni-Cr.

scholarly journals New Method for Generating New Families of Distributions

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 726
Author(s):  
Lamya A. Baharith ◽  
Wedad H. Aljuhani
Keyword(s):  
Exponential Distribution ◽  
Real Data ◽  
Rate Function ◽  
New Method ◽  
Likelihood Method ◽  
Alpha Power ◽  
Unknown Parameters ◽  
Failure Rate Function ◽  
New Approach ◽  
Numerical Studies

This article presents a new method for generating distributions. This method combines two techniques—the transformed—transformer and alpha power transformation approaches—allowing for tremendous flexibility in the resulting distributions. The new approach is applied to introduce the alpha power Weibull—exponential distribution. The density of this distribution can take asymmetric and near-symmetric shapes. Various asymmetric shapes, such as decreasing, increasing, L-shaped, near-symmetrical, and right-skewed shapes, are observed for the related failure rate function, making it more tractable for many modeling applications. Some significant mathematical features of the suggested distribution are determined. Estimates of the unknown parameters of the proposed distribution are obtained using the maximum likelihood method. Furthermore, some numerical studies were carried out, in order to evaluate the estimation performance. Three practical datasets are considered to analyze the usefulness and flexibility of the introduced distribution. The proposed alpha power Weibull–exponential distribution can outperform other well-known distributions, showing its great adaptability in the context of real data analysis.

Cholinium-amino acid based ionic liquids: a new method of synthesis and physico-chemical characterization

2015 ◽  
Vol 17 (32) ◽  
pp. 20687-20698 ◽  
Author(s):  
Serena De Santis ◽  
Giancarlo Masci ◽  
Francesco Casciotta ◽  
Ruggero Caminiti ◽  
Eleonora Scarpellini ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Amino Acid ◽  
Room Temperature ◽  
Chemical Characterization ◽  
New Method ◽  
Room Temperature Ionic Liquids ◽  
Synthetic Method ◽  
Chemical Structures ◽  
Physico Chemical ◽  
Wide Range

Fourteen cholinium-amino acid based room temperature ionic liquids were prepared using a cleaner synthetic method. Chemicophysical properties were well correlated with the wide range of amino acid chemical structures.

Comparison of New Telescopic Video Microlaryngoscopic and Standard Microlaryngoscopic Techniques

1992 ◽  
Vol 101 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Eiji Yanagisawa ◽  
Ken Yanagisawa ◽  
Jay B. Horowitz ◽  
Lawrence J. Mambrino
Keyword(s):  
Video Camera ◽  
New Method ◽  
Depth Of Field ◽  
Microscopic Technique ◽  
New Approach ◽  
Advantages And Disadvantages ◽  
Laryngeal Surgery ◽  
Valuable Method ◽  
Microlaryngeal Surgery ◽  
Television Image

A new approach to microlaryngeal surgery using a specially designed video microlaryngoscope with a rigid endoscopic telescope and an attached video camera was introduced by Kantor et al in 1990. The ability to video document and perform surgery of the larynx by viewing a high-resolution television image was demonstrated. This method was recommended over the standard microscopic technique for increased visibility with greater depth of field, unimpeded instrument access, instant documentation, and superior teaching value. The authors tried this new method and the standard microscopic technique at the same sitting on a series of patients. This paper will compare these two different techniques and discuss their advantages and disadvantages. Although the new method has many advantages, the standard microscopic technique remains as a valuable method in laryngeal surgery.

Inferring age from otolith measurements: a review and a new approach

2004 ◽  
Vol 61 (7) ◽  
pp. 1269-1284 ◽  
Author(s):  
RIC Chris Francis ◽  
Steven E Campana
Keyword(s):  
Simulation Experiment ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
New Method ◽  
Population Parameters ◽  
Benefit Analysis ◽  
Mixture Analysis ◽  
New Approach ◽  
Individual Fish ◽  
The Cost

In 1985, Boehlert (Fish. Bull. 83: 103–117) suggested that fish age could be estimated from otolith measurements. Since that time, a number of inferential techniques have been proposed and tested in a range of species. A review of these techniques shows that all are subject to at least one of four types of bias. In addition, they all focus on assigning ages to individual fish, whereas the estimation of population parameters (particularly proportions at age) is usually the goal. We propose a new flexible method of inference based on mixture analysis, which avoids these biases and makes better use of the data. We argue that the most appropriate technique for evaluating the performance of these methods is a cost–benefit analysis that compares the cost of the estimated ages with that of the traditional annulus count method. A simulation experiment is used to illustrate both the new method and the cost–benefit analysis.

A Novel and Efficient Alkoxylselenenylation of Alkenes

2019 ◽  
Vol 41 (6) ◽  
pp. 1039-1039
Author(s):  
Yingguo Fang and Jie Yan Yingguo Fang and Jie Yan
Keyword(s):  
Room Temperature ◽  
Electrophilic Addition ◽  
New Method ◽  
Reaction Conditions ◽  
Selenium Species

A novel and efficient alkoxylselenenylation from alkenes, diselenides, and alcohols mediated by iodine is developed, with which a series of β-alkoxy selenides are synthesized. In this procedure, firstly, I2 reacts with diselenide to form in situ the active electrophilic selenium species RSeI, then following an electrophilic addition of it to alkenes provides β-alkoxy selenides with high regioselectivity and in good yields. This new method for achieving β-alkoxy selenides has some advantages over other methods such as using available and cheap iodine as the oxidizing species at room temperature, which makes this reaction has milder reaction conditions and simpler procedure.

Heteroepitaxy and Characterization of Low-Dislocation-Density GaN on Periodically Grooved Substrates

2000 ◽  
Vol 639 ◽  
Author(s):  
T. Detchprohm ◽  
M. Yano ◽  
R. Nakamura ◽  
S. Sano ◽  
S. Mochiduki ◽  
...  
Keyword(s):  
Dislocation Density ◽  
New Method ◽  
Growth Technique ◽  
New Approach ◽  
Density Area ◽  
Low Dislocation Density ◽  
Dislocation Densities ◽  
Movpe Growth

ABSTRACTWe have developed a new method to prepare low-dislocation-density GaN by using periodically grooved substrates in a conventional MOVPE growth technique. This new approach was demonstrated for GaN grown on periodically grooved α-Al2O3(0001), 6H-SiC(0001)Si and Si(111) substrates. Dislocation densities were 2×107 cm−2 in low-dislocation-density area.

scholarly journals A New Approach to Gauging Inflation Expectations

2009 ◽  
pp. 1-4
Author(s):  
Joseph G. Haubrich
Keyword(s):  
Interest Rates ◽  
Risk Premium ◽  
New Method ◽  
Inflation Expectations ◽  
Real Interest Rates ◽  
Inflation Risk ◽  
New Approach ◽  
Expected Inflation ◽  
Inflation Risk Premium

This Economic Commentary explains a relatively new method of uncovering inflation expectations, real interest rates, and an inflation-risk premium. It provides estimates of expected inflation from one month to 30 years, an estimate of the inflation-risk premium, and a measure of real interest rates, particularly a short (one-month) rate, which is not readily available from the TIPS market. Calculations using the method suggest that longer-term inflation expectations remain near historic lows. Furthermore, the inflation-risk premium is also low, which in the model means that inflation is not expected to deviate far from expectations.

scholarly journals New Method for Nucleophilic Substitution on Hexachlorocyclotriphosphazene by Allylamine Using an Algerian Proton Exchanged Montmorillonite Clay (Maghnite-H+) as a Green Solid Catalyst

2016 ◽  
Vol 11 (2) ◽  
pp. 151 ◽  
Author(s):  
Lahouaria Medjdoub ◽  
Belbachir Mohammed
Keyword(s):  
Nucleophilic Substitution ◽  
Room Temperature ◽  
Montmorillonite Clay ◽  
New Method ◽  
Solid Catalyst ◽  
H Nmr ◽  
Flight Mass Spectrometry ◽  
Crystalline Product ◽  
First Time ◽  
C Nmr

<p>Nucleophilic substitution on hexachlorocyclotriphosphazene (HCCTP) with allylamine in order to give hexa(allylamino)cyclotriphosphazene (HACTP)  is performed for the first time under mild conditions by using diethylether as solvent to replace benzene which is very toxic. The reaction time is reduced to half and also performed at room temperature but especially in the presence of an eco-catalyst called Maghnite-H<sup>+</sup>. This catalyst has a significant role in the industrial scale. In fact, the use of Maghnite is preferred for its many advantages: a very low purchase price compared to other catalysts, the easy removal of the reaction mixture. Then, Maghnite-H<sup>+</sup> is became an excellent catalyst for many chemical reactions. The structure of HACTP synthesized in the presence of Maghnite-H<sup>+</sup> to 5% by weight is confirmed by <sup>1</sup>H-NMR, <sup>13</sup>C-NMR, <sup>31</sup>P-NMR (Nuclear magnetic resonance) and FTIR (Fourier Transform Infrared spectroscopy). MALDI-TOF (Matrix-Assisted Laser Desorption/Ionisation-time-of-flight mass spectrometry) is used to establish the molecular weight of HACTP which is 471 g/mol. DSC (Differential Scanning Calorimetery) and TGA (Thermogravimetric Analysis) show that HACTP is a crystalline product with a melting point of 88 °C. It is reactive after melting but is degraded from 230 °C. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 28<sup>th</sup> September 2015; Revised: 5<sup>th</sup> December 2015; Accepted: 4<sup>th</sup> January 2016</em></p><p><strong>How to Cite</strong>: Medjdoub, L., Mohammed, B. (2016). New Method for Nucleophilic Substitution on Hexachlorocyclotriphosphazene by Allylamine Using an Algerian Proton Exchanged Montmorillonite Clay (Maghnite-H+) as a Green Solid Catalyst. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (2): 151-160 (doi:10.9767/bcrec.11.2.541.151-160)</p><p><strong>Permalink/DOI:</strong> http://dx.doi.org/10.9767/bcrec.11.2.541.151-160</p>

Application of the Hansen Solubility Parameters Theory to Carbon Nanotubes

2008 ◽  
Vol 8 (11) ◽  
pp. 6082-6092 ◽  
Author(s):  
S. Detriche ◽  
G. Zorzini ◽  
J.-F. Colomer ◽  
A. Fonseca ◽  
J. B. Nagy
Keyword(s):  
Carbon Nanotubes ◽  
Present Approach ◽  
New Method ◽  
Solubility Parameters ◽  
Hansen Solubility Parameters ◽  
High Solubility ◽  
New Approach ◽  
Hansen Solubility

Carbon nanotubes (CNT) are very promising nano-objects due to their exceptional properties. However, their tendency to form bundles as well as their insolubility in common solvents makes them difficult to handle. The main way to solve the problem is chemical or physical CNTs functionalisations, with all the problems inherent to the methods. In this contribution, we present a new approach that allows predicting the solubility of carbon nanotubes in many solvents but also predicting the most appropriate solvents to use for given samples of CNTs. Solubilisation and dispersion being directly connected, the present approach of solubilisation proves also to be efficient in dispersing the CNTs bundles. This contribution is a first step toward the control of carbon nanotube's dispersion in polymers and their homogenous functionalisation. Moreover, we also report here a new method, based on solvents, to separate carbon nanotubes by size, the use of mixture of non-solvents in order to obtain good solvents and the use of mixture of good solvents to obtain higher solubility. The use of mixture of good solvents allowed us to obtain high solubility, up to three times higher then that reported in literature. We have also measured and analysed the solubility of some functionalised carbon nanotubes.

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