Sulfur transfer reactions of tetrathiomolybdate in water: Synthesis of alkyl disulfides from alkyl halides

Reaction of a number of alkyl halides with tetrathiomolybdate in water as the solvent affords the corresponding disulfides in good yields.

Synthesis of thiolactones using benzyltriethylammonium tetrathiomolybdate as sulfur transfer reagent

An interesting sulfur transfer reaction mediated by benzyltriethylammonium tetrathiomolybdate [(PhCH2NEt3)(2)MoS4] converts omega-halo acid chlorides to the corresponding thiolactones in moderate to good yields in one step. (C) 1997 Elsevier Science Ltd.

The prop-2-ynyloxy carbonyl function (POC): A new amino-protecting group removable from sulfur-containing peptides by ultrasonic irradiation with tetrathiomolybdate under mild and neutral conditions

The prop-2-ynyloxy carbonyl function (POC) which can be cleaved under mild and neutral conditions in the presence of benzyltriethylammonium tetrathiomolybdate has been developed as a new protecting group for amines. (C) 1999 Elsevier Science Ltd. All rights reserved.

Structural model for the Cu-B site of dopamine beta-hydroxylase: Crystal structure of a copper(II) complex showing N3OS coordination with an axial sulfur ligation

A copper(II) complex containing a NSO-donor Schiff base and NN-donor 2,2'-bipyridine has been prepared and structurally characterized. The square pyramidal complex with an axial sulfur ligation is a structural model for the CUB site of dopamine-hydroxylase in its oxidized form. The copper(II) complex is catalytically active in the oxidation of ascorbic acid by dioxygen mediated by a copper(I) species which is proposed to have a four-coordinate structure with a N3S coordination geometry.

The hydrolytic reactivities of N-methyl-N(methylthiomethyl)acetamide and N-acetyl-1,3-thiazolidine: the influence of the sulfur atom

The sulfur atom in the substrates leads to modest enhancements in the titled phenomena: these are essentially derived from favourable enthalpies of activation, the negative entropies of activation possibly indicating a measure of stereoelectronic control.

Development and studies on microstrip detector

We report development of gas microstrip detectors using thin film and lithography techniques. The detectors were tested for their performance for X-rays (5.9 keV) and a maximum gas gain of similar to 13,000 and best resolution of similar to 12% was obtained. Factors affecting gain and resolution were investigated. The detectors were tested for their one-dimensional position sensitivity. Meandering resistive strips were used for charge division method. A position resolution of 0.48 mm was obtained.

Solution processed reduced graphene oxide ultraviolet detector

Electronic properties of graphene have been studied more extensively than its photonic applications, in spite of its exciting optical properties. Recent results on solar cells, light emitting diodes and photodetectors show its true potential in photonics and optoelectronics. Here, we have explored the use of reduced graphene oxide as a candidate for solution processed ultraviolet photodetectors. UV detection is demonstrated by reduced graphene oxide in terms of time resolved photocurrent as well as photoresponse. The responsivity of the detectors is found to be 0.12 A/W with an external quantum efficiency of 40%. (C) 2011 American Institute of Physics. [doi:10.1063/1.3640222]

A Sensor for Sulfur Gas Based on Silver β-Alumina

EMF measurements were made with an electrochemical cell of the type ~t/&(s)/&+-beta alumina/Ag~S(s)S. 2(g). S(s or 1)/R at temperatures between 95 and 241°C. Sflver $- alumina was prepared with the ion exchange technique. The patial pressure of diatomic gas obtained from cell voltages agreed with the literature data.

Design and performance analysis of a signal detector based on suprathreshold stochastic resonance

This paper presents the design and performance analysis of a detector based on suprathreshold stochastic resonance (SSR) for the detection of deterministic signals in heavy-tailed non-Gaussian noise. The detector consists of a matched filter preceded by an SSR system which acts as a preprocessor. The SSR system is composed of an array of 2-level quantizers with independent and identically distributed (i.i.d) noise added to the input of each quantizer. The standard deviation sigma of quantizer noise is chosen to maximize the detection probability for a given false alarm probability. In the case of a weak signal, the optimum sigma also minimizes the mean-square difference between the output of the quantizer array and the output of the nonlinear transformation of the locally optimum detector. The optimum sigma depends only on the probability density functions (pdfs) of input noise and quantizer noise for weak signals, and also on the signal amplitude and the false alarm probability for non-weak signals. Improvement in detector performance stems primarily from quantization and to a lesser extent from the optimization of quantizer noise. For most input noise pdfs, the performance of the SSR detector is very close to that of the optimum detector. (C) 2012 Elsevier B.V. All rights reserved.

Single electron transfer-driven multi-dimensional signal read-out function of TCNQ as an ``off-the-shelf'' detector for cyanide

Herein we report the first applications of TCNQ as a rapid and highly sensitive off-the-shelf cyanide detector. As a proof-of-concept, we have applied a kinetically selective single-electron transfer (SET) from cyanide to deep-lying LUMO orbitals of TCNQ to generate a persistently stable radical anion (TCNQ(center dot-)), under ambient condition. In contrast to the known cyanide sensors that operate with limited signal outputs, TCNQ(center dot-) offers a unique multiple signaling platform. The signal readability is facilitated through multichannel absorption in the UV-vis-NIR region and scattering-based spectroscopic methods like Raman spectroscopy and hyper Rayleigh scattering techniques. Particularly notable is the application of the intense 840 nm NIR absorption band to detect cyanide. This can be useful for avoiding background interference in the UV-vis region predominant in biological samples. We also demonstrate the fabrication of a practical electronic device with TCNQ as a detector. The device generates multiorder enhancement in current with cyanide because of the formation of the conductive TCNQ(center dot-).

The Presence of Multiple Cellular Defects Associated with a Novel G50E Iron-Sulfur Cluster Scaffold Protein ( ISCU) Mutation Leads to Development of Mitochondrial Myopathy

Background: Muscle-specific deficiency of iron-sulfur (Fe-S) cluster scaffold protein (ISCU) leads to myopathy. Results: Cells carrying the myopathy-associated G50E ISCU mutation demonstrate impaired Fe-S cluster biogenesis and mitochondrial dysfunction. Conclusion: Reduced mitochondrial respiration as a result of diminished Fe-S cluster synthesis results in muscle weakness in myopathy patients. Significance: The molecular mechanism behind disease progression should provide invaluable information to combat ISCU myopathy. Iron-sulfur (Fe-S) clusters are versatile cofactors involved in regulating multiple physiological activities, including energy generation through cellular respiration. Initially, the Fe-S clusters are assembled on a conserved scaffold protein, iron-sulfur cluster scaffold protein (ISCU), in coordination with iron and sulfur donor proteins in human mitochondria. Loss of ISCU function leads to myopathy, characterized by muscle wasting and cardiac hypertrophy. In addition to the homozygous ISCU mutation (g.7044GC), compound heterozygous patients with severe myopathy have been identified to carry the c.149GA missense mutation converting the glycine 50 residue to glutamate. However, the physiological defects and molecular mechanism associated with G50E mutation have not been elucidated. In this report, we uncover mechanistic insights concerning how the G50E ISCU mutation in humans leads to the development of severe ISCU myopathy, using a human cell line and yeast as the model systems. The biochemical results highlight that the G50E mutation results in compromised interaction with the sulfur donor NFS1 and the J-protein HSCB, thus impairing the rate of Fe-S cluster synthesis. As a result, electron transport chain complexes show significant reduction in their redox properties, leading to loss of cellular respiration. Furthermore, the G50E mutant mitochondria display enhancement in iron level and reactive oxygen species, thereby causing oxidative stress leading to impairment in the mitochondrial functions. Thus, our findings provide compelling evidence that the respiration defect due to impaired biogenesis of Fe-S clusters in myopathy patients leads to manifestation of complex clinical symptoms.