Electroanalytical Overview: The Electroanalytical Sensing of Hydrazine

In this overview, we explore the electroanalytical sensing of the important chemical reagent hydrazine, highlighting the plethora of electrochemical sensing strategies utilised from the first reports in 1951 to the...

A Laboratory Manual for the Preparation of Chemical Reagents, Solutions and Special Indicators

A Laboratory Manual for the Preparation of Chemical Reagents, Solutions and Special Indicators. ETHIOPIAN BIODIVERSITY INSTITUTE, Microbial Biodiversity Directorate. This manual includes detailed view of the following: Laboratory Safety Precautions, Chemical Reagent Preparation, Buffer and Chemical Solution Preparation, Staining Solution Preparation, Indicators and Dye Solution Preparation, Preparation of Special Reagents, Known and Suspected List of Carcinogens and References.

Molecular Descriptors and Topological Analysis of Cyclooctane Derivatives

Cyclooctane is mainly used in the synthesis of cyclooctanone, cyclooctanol, caprolactam and octanoic acid. At the same time, it can also be used as an intermediate in organic synthesis and a chemical reagent. By discussing the resistance distance between any two points of cyclooctane derivative Tn(C8), some invariants about resistance distance are obtained, such as Kirchhoff index, multiplicative degree-Kirchhoff index, and additive degree-Kirchhoff index. Topological index can help scholars better understand some physical and chemical properties of compounds, and we obtain the closed expressions of valency-based topological indices for Tn(C8), such as ABC index, GA index, etc.

Blue-LED Calibration on DOAS System to Measure Nitrogen Dioxide Emission Compared with USEPA Method 7B Standard

Air polution level measurement sometime needs tricky instrumentation, costly, and use chemical reagent that could bad impact to environment, it also time consuming for analysis. In other hand, air polution level measurement, include nitrogen dioxide (NO2) needs accuracy, rapid and environment friendly for its analysis and measurement. Differential Optical Absorption Spectroscopy (DOAS) develop as spectrum measurements both UV and visible, transmitted by specific canal using absorption Lambert Beer’s Law principal. On this basic method, NO2 measurement needs light source with 330 – 500 nm wavelength, it is possible to use cheap blue-LED for this measurement. This research intends to calibrate prototype instrumentation for measuring NO2 by DOAS based using Blue-LED (375 nm) passed in continual gas container. NO2 emission simulated in laboratory scale by reacting copper (Cu) with nitric acid (HNO3) result NO2 gas formation. Blue-LED spectrum analysed by compact CCD Spectrometer for its absorbance spectrum, then calibrated with NO2 measurement using USEPA Method 7B standard that is commonly used in testing laboratory as standard method for NO2 measurement. It has good corelation between spectrum absorbance in CCD Spectrometer to USEPA Method 7B with more than 95% linierity. As rapidity of this measurement and shown good accuracy, more development for this method could carry fast, accurate, cheap, also environmentally friendly method for NO2 measurement.

Evaluation of a novel Nano diagnostic assay for Assessing the Prevalence of Schistosoma haematobium Infection in Areas at Risk in Upper Egypt

Background Urogenital schistosomiasis caused by Schistosoma heamatobium is one of the major public health problems worldwide. It is thought that despite extensive efforts and integrated control programs implicated over the last few decades, the global disease burden of schistosomiasis remains unacceptably high. This persistence of the disease may be due to in part the lack of accurate diagnostic tools for case detection and community screening in endemic areas. Aim of the work The present work aims to develop a novel nano-diagnostic assay using gold nanoparticles (nanomagnetic beads based- ELISA) which can utilize larger surface area, achieving a higher sensitivity for detection of urinary schistosomal egg antigen (SEA) in urine of human schistosomiasis haematobium and comparing it with the traditional sandwich ELISA and direct microscopic examination of urine sediments together with indirect screening by chemical reagent strips for microhaematiria and proteinuria for assessing prevalence of urinary schistosomiasis in some villages in Beni-Suef governorate. Subjects and methods A cross sectional study was conducted on 290 students (192 male and 98 female) selected randomly from Primary and Preparatory schools in four villages in Beni-Suef governorate; The participating children were aged 8–15 years old. A simple questionnaire was designed based on the key indicators of urinary schistosomiasis then, terminal urine samples were collected between 10 am and 2 pm in clean container from each participant to be screened by chemical reagent strips (Combi 10) and examined by urine microscopy and sandwich ELISA techniques (traditional and IMB) for S. haematobium detection. Soluble egg antigen (SEA) was used to produce specific polyclonal antibodies (pAbs) which were then used as a primary capture in the sandwich ELISA techniques. The anti-SEA pAbs were labeled with horse-radish peroxidase (HRP) and used as a secondary capture. Results Out of the 290 participants, 39 children (13.4%) were positive by UM, 53 were positive by traditional sandwich ELISA, with diagnostic sensitivity (87.2%) and specificity (92.4%) and 50 were positive by IMB-sandwich ELISA with diagnostic sensitivity (94.9%) and specificity (95.2%)based on UM results. Micro-haematuria and proteinuria were assessed by chemical reagent strips which gave sensitivity of 29.5%, specificity of 90.8% for micro-haematuria alone, sensitivity of 18.4%, specificity of 92.4% for proteinuria alone, while sensitivity of 35.9%, specificity of 94.9% for combined micro-haematuria and proteinuria which indicated a highly significant association with S. haematobium infection (p value<0.001). Conclusion Combination of both clinical and epidemiological data in addition to sensitive diagnostic tools is essential for diagnosis. The present study as with other studies revealed that, IMB-ELISA based on gold nanoparticles provides more rapid and sensitive detection for SEA in urine samples of patient with active schistosomiasis. Simplicity and fast detection (10 min) are its main advantages. Moreover, its high sensitivity and specificity ensure its application with greater precision and rapid detection. Also, in addition, the prevalence of urinary schistosomiasis in these regions is considered relatively high requiring rapid implementation of control programs to decrease the prevalence and improve the community's health status.

Phytochemical Analysis and Traditional uses of two locally available Ficus species (beneghalensis and sycomorus)

Two Ficus species that are commonly used in Sudanese Traditional Medicine for the management of various ailments were screened for their phytochemical groups using chemical reagent and Thin Layer Chromatography. Qualitative phytochemical tests were used to detect the presence of flavonoids, saponins, tannins, alkaloids, phenolic compounds and anthraquinones. Six compounds from F. benegalensis and seven from F. sycomorus quenching were reported from the various parts of these two plants. However , more number of compounds were found in the leaves. The data generated from this study have provided the chemical basis for wide use of F. sycomorus as therapeutic agent for treating various ailments. However, there is need to further carry out advanced hyphenated spectroscopic studies in order to elucidate the structure of these compounds. Furthermore, this data may be handy in probing of biochemistry of this plant in the future.

Sustainable and feasible reagent-free electro-Fenton via sequential dual-cathode electrocatalysis

Electro-Fenton processes aim at producing oxidizing radicals with fewer added chemicals and residues but are still unable to completely eliminate both. This study demonstrates that a reagent-free electro-Fenton process that runs solely on oxygen and electricity can be achieved by sequential dual-cathode electrocatalysis. H2O2 is produced on an electrodeposited PEDOT on carbon cloth (PEDOT/CC) cathode and subsequently converted to hydroxyl radicals on a stainless-steel–mesh cathode. The dual-cathode system demonstrates efficient decolorization and total organic carbon (TOC) removal toward organic dyes at optimized cathodic potentials of −0.9 V for PEDOT/CC and −0.8 V for the stainless-steel mesh. The sequential dual-cathode process also displays high reusability, no iron leaching, high removal efficiency using air instead of oxygen, and low installation and operation costs. This work demonstrates a preeminent and commercially viable example of pollution control rendered by the “catalysis instead of chemical reagent” philosophy of green chemistry.

Numerical Analysis of the Bond Strength between Two Methacrylic Polymers by Surface Modification

The creation of acrylic dentures involves many stages. One of them is to prepare the surfaces of artificial teeth for connection with the denture plates. The teeth could be rubbed with a chemical reagent, the surface could be developed, or retention hooks could be created. Preparation of the surface is used to improve the bond between the teeth and the plate. Choosing the right combination affects the length of denture use. This work focuses on a numerical analysis of grooving. The purpose of this article is to select the shape and size of the grooves that would most affect the quality of the bond strength. Two types of grooves in different dimensional configurations were analyzed. The variables were groove depth and width, and the distance between the grooves. Finally, 24 configurations were obtained. Models were analyzed in terms of their angular position to the loading force. Finite element method (FEM) analysis was performed on the 3D geometry created, which consisted of two polymer bodies under the shear process. The smallest values of the stresses and strains were characterized by a sample with parallel grooves with the grooving dimensions width 0.20 mm, thickness 0.10 mm, and distance between the grooves 5.00 mm, placed at an angle of 90°. The best dimensions from the parallel (III) and cross (#) grooves were compared experimentally. Specimens with grooving III were not damaged in the shear test. The research shows that the shape of the groove affects the distribution of stresses and strains. Combining the selected method with an adequately selected chemical reagent can significantly increase the strength of the connection.

Site-Specific Conversion of Cysteine in a Protein to Dehydroalanine Using 2-Nitro-5-thiocyanatobenzoic Acid

Dehydroalanine exists natively in certain proteins and can also be chemically made from the protein cysteine. As a strong Michael acceptor, dehydroalanine in proteins has been explored to undergo reactions with different thiolate reagents for making close analogues of post-translational modifications (PTMs), including a variety of lysine PTMs. The chemical reagent 2-nitro-5-thiocyanatobenzoic acid (NTCB) selectively modifies cysteine to form S-cyano-cysteine, in which the S–Cβ bond is highly polarized. We explored the labile nature of this bond for triggering E2 elimination to generate dehydroalanine. Our results indicated that when cysteine is at the flexible C-terminal end of a protein, the dehydroalanine formation is highly effective. We produced ubiquitin and ubiquitin-like proteins with a C-terminal dehydroalanine residue with high yields. When cysteine is located at an internal region of a protein, the efficiency of the reaction varies with mainly hydrolysis products observed. Dehydroalanine in proteins such as ubiquitin and ubiquitin-like proteins can serve as probes for studying pathways involving ubiquitin and ubiquitin-like proteins and it is also a starting point to generate proteins with many PTM analogues; therefore, we believe that this NTCB-triggered dehydroalanine formation method will find broad applications in studying ubiquitin and ubiquitin-like protein pathways and the functional annotation of many PTMs in proteins such as histones.

Gd Matrix Effects on Eu Isotope Fractionation in Geological Rocks Using MC-ICP-MS: Optimizing Europium Isotope Ratio Measurements in Geological Samples

<p></p><p>Eu has only two isotopes (151Eu and 153 Eu). Eu and Gd are one of the rare earth elements that are very difficult to completely separate from each other. Eu isotope ratio can be determined by MC-ICP-MS using internal Sm or Gd spikes to correct for mass discrimination. NIST3117a ultrapure chemical reagent shows almost no Eu isotope fractionation regardless of the kind of normalization isotope pair. However, Eu isotope ratio in the silicate rocks was effected by Gd matrix during MC-ICP-MS measurement if a trace amount of Gd impurity remains in the purified Eu fraction. In this report, we tried to determine optimizing conditions for precise and accurate Europium isotope ratio measurements in geological samples using MC-ICP-MS. The pure Eu fraction with almost no Gd matrix separated from geological samples and NIST3117a ultrapure chemical reagent show almost same degree of Eu isotope fractionation regardless of the kind of normalization isotope pair. However, Eu isotope ratio in the silicate rocks was effected by Gd matrix during MC-ICP-MS measurement using if 154 Gd interference relative to 154 Sm as internal standard is more than ca. 0.1%. Particularly, highly fractionated granite and high silica volcanic rock with extremely low Eu concentration compared to Gd require high – purity Eu separation with a high recovery rate to obtain the true value of the Eu isotope fractionation in the geological rocks. <br></p><br><p></p>