Gadolinium(III) ion selective sensor using a new synthesized Schiff's base as a sensing material

2012 ◽  
Vol 32 (4) ◽  
pp. 712-717 ◽  
Author(s):  
Hassan Ali Zamani ◽  
Majid Mohammadhosseini ◽  
Saeed Haji-Mohammadrezazadeh ◽  
Farnoush Faridbod ◽  
Mohammad Reza Ganjali ◽  
...  
Keyword(s):  
Schiff’S Base ◽  
Sensing Material ◽  
Selective Sensor

Quantitative Analysis of Holmium Ion by a Ho3+ Ion-Selective Sensor Based on a Symmetric Thio-Schiff's Base

2011 ◽  
Vol 29 (7) ◽  
pp. 1523-1528 ◽  
Author(s):  
Ali Zamani Hassan ◽  
Rahimi Fatemeh ◽  
Naghavi-Reyabbi Fatemeh ◽  
Arvinfar Ali ◽  
Imani Alihossien ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Schiff’S Base ◽  
Holmium Ion ◽  
Selective Sensor

Aldehyde gold clusters for molecular labeling

1995 ◽  
Vol 53 ◽  
pp. 858-859
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya
Keyword(s):  
Covalent Bond ◽  
Aldehyde Group ◽  
Gold Clusters ◽  
Side Reactions ◽  
Amino Groups ◽  
Sodium Cyanoborohydride ◽  
Schiff’S Base ◽  
Protein Molecules ◽  
Hydroxysuccinimide Esters ◽  
Primary Amino

Glutaraldehyde is a useful tissue and molecular fixing reagents. The aldehyde moiety reacts mainly with primary amino groups to form a Schiff's base, which is reversible but reasonably stable at pH 7; a stable covalent bond may be formed by reduction with, e.g., sodium cyanoborohydride (Fig. 1). The bifunctional glutaraldehyde, (CHO-(CH2)3-CHO), successfully stabilizes protein molecules due to generally plentiful amines on their surface; bovine serum albumin has 60; 59 lysines + 1 α-amino. With some enzymes, catalytic activity after fixing is preserved; with respect to antigens, glutaraldehyde treatment can compromise their recognition by antibodies in some cases. Complicating the chemistry somewhat are the reported side reactions, where glutaraldehyde reacts with other amino acid side chains, cysteine, histidine, and tyrosine. It has also been reported that glutaraldehyde can polymerize in aqueous solution. Newer crosslinkers have been found that are more specific for the amino group, such as the N-hydroxysuccinimide esters, and are commonly preferred for forming conjugates. However, most of these linkers hydrolyze in solution, so that the activity is lost over several hours, whereas the aldehyde group is stable in solution, and may have an advantage of overall efficiency.

scholarly journals Optimization of a Low-Power Chemoresistive Gas Sensor: Predictive Thermal Modelling and Mechanical Failure Analysis

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 783 ◽  
Author(s):  
Andrea Gaiardo ◽  
David Novel ◽  
Elia Scattolo ◽  
Michele Crivellari ◽  
Antonino Picciotto ◽  
...  
Keyword(s):  
Low Power ◽  
Failure Analysis ◽  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Mechanical Failure ◽  
Sensing Applications ◽  
Theoretical Approaches ◽  
Sensing Material ◽  
Silicon Bulk

The substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane sizes were developed using the microfabrication process. The performance of these devices was evaluated to predict their thermal and mechanical behaviors by using both experimental and theoretical approaches. Finally, a statistical method was employed to cross-correlate the thermal predictive model and the mechanical failure analysis, aiming at microheater design optimization for gas-sensing applications.

scholarly journals Lipid Metabolic Events Underlying the Formation of the Corneocyte Lipid Envelope

2021 ◽  
pp. 1-13
Author(s):  
Philip W. Wertz
Keyword(s):  
Stratum Corneum ◽  
Outer Surface ◽  
Barrier Function ◽  
Skin Surface ◽  
Schiff’S Base ◽  
Cornified Envelope ◽  
Epoxy Alcohol ◽  
Viable Epidermis ◽  
Transglutaminase 1 ◽  
Base Formation

Cornified cells of the stratum corneum have a monolayer of an unusual lipid covalently attached to the outer surface. This is referred to as the corneocyte lipid envelope (CLE). It consists of a monolayer of ω-hydroxyceramides covalently attached to the outer surface of the cornified envelope. The CLE is essential for proper barrier function of the skin and is derived from linoleate-rich acylglucosylceramides synthesized in the viable epidermis. Biosynthesis of acylglucosylceramide and its conversion to the cornified envelope is complex. Acylglucosylceramide in the bounding membrane of the lamellar granule is the precursor of the CLE. The acylglucosylceramide in the limiting membrane of the lamellar granule may be oriented with the glucosyl moiety on the inside. Conversion of the acylglucosylceramide to the CLE requires removal of the glucose by action of a glucocerebrosidase. The ester-linked fatty acid may be removed by an as yet unidentified esterase, and the resulting ω-hydroxyceramide may become ester linked to the outer surface of the cornified envelope through action of transglutaminase 1. Prior to removal of ester-linked fatty acids, linoleate is oxidized to an epoxy alcohol through action of 2 lipoxygenases. This can be further oxidized to an epoxy-enone, which can spontaneously attach to the cornified envelope through Schiff’s base formation. Mutations of genes coding for enzymes involved in biosynthesis of the CLE result in ichthyosis, often accompanied by neurologic dysfunction. The CLE is recognized as essential for barrier function of skin, but many questions about details of this essentiality remain. What are the relative roles of the 2 mechanisms of lipid attachment? What is the orientation of acylglucosylceramide in the bounding membrane of lamellar granules? Some evidence supports a role for CLE as a scaffold upon which intercellular lamellae unfold, but other evidence does not support this role. There is also controversial evidence for a role in stratum corneum cohesion. Evidence is presented to suggest that covalently bound ω-hydroxyceramides serve as a reservoir for free sphingosine that can serve in communicating with the viable epidermis and act as a potent broad-acting antimicrobial at the skin surface. Many questions remain.

scholarly journals A Molecularly Imprinted Sol-Gel Electrochemical Sensor for Naloxone Determination

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 631
Author(s):  
Narges Shaabani ◽  
Nora W. C. Chan ◽  
Abebaw B. Jemere
Keyword(s):  
Indium Tin Oxide ◽  
Sol Gel ◽  
Electrochemical Techniques ◽  
Electrochemical Determination ◽  
Multiwall Carbon Nanotube ◽  
Molecularly Imprinted ◽  
Gel Layer ◽  
Sensing Material ◽  
Relative Standard ◽  
Optimized Conditions

A molecularly imprinted sol-gel is reported for selective and sensitive electrochemical determination of the drug naloxone (NLX). The sensor was developed by combining molecular imprinting and sol-gel techniques and electrochemically grafting the sol solution onto a functionalized multiwall carbon nanotube modified indium-tin oxide (ITO) electrode. The sol-gel layer was obtained from acid catalyzed hydrolysis and condensation of a solution composed of triethoxyphenylsilane (TEPS) and tetraethoxysilane (TES). The fabrication, structure and properties of the sensing material were characterized via scanning electron microscopy, spectroscopy and electrochemical techniques. Parameters affecting the sensor’s performance were evaluated and optimized. A sensor fabricated under the optimized conditions responded linearly between 0.0 µM and 12 µM NLX, with a detection limit of 0.02 µM. The sensor also showed good run-to-run repeatability and batch-to-batch performance reproducibility with relative standard deviations (RSD) of 2.5–7.8% (n = 3) and 9.2% (n = 4), respectively. The developed sensor displayed excellent selectivity towards NLX compared to structurally similar compounds (codeine, fentanyl, naltrexone and noroxymorphone), and was successfully used to measure NLX in synthetic urine samples yielding recoveries greater than 88%.

Schiff's base (SB) modified zirconium dioxide reinforced PLA bio-composite film for industrial packaging applications

2021 ◽  
pp. 100750
Author(s):  
N. Sundar ◽  
S. Ananda Kumar ◽  
P. Keerthana ◽  
S. Johan Stanley ◽  
G. Ananda Kumar
Keyword(s):  
Composite Film ◽  
Zirconium Dioxide ◽  
Schiff’S Base ◽  
Industrial Packaging
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