Safety Critical Systems Analysis

Abstract - A brief overview of the fields that must be considered when designing, implementing safety-critical systems is presented. The notion of safety is most likely to come to mind when we drive a car, fly on an airliner, or take an elevator ride. In each case, we are concerned with the threat of a mishap, which defined as an unplanned event or series of events that result in death, injury, occupational illness, damage to or loss of equipment or property or damage to the environment

Studies of Phosphazenes: Part II*-Reactions of Hexachlorocyclotriphosphazatriene with N-Methylaniline

823-82

Oxidation by chloramine-T. Part II. Redox potential of chloramine-T-sulphonamide systems

This article does not have an abstract

Retinal vascular tortuosity in schizophrenia and bipolar disorder

\u3cp\u3eThe micro-vasculature of retina and brain share common morphological, physiological, and pathological properties. Retina being easily accessible, retinal vascular examination provides an indirect assessment of cerebral vasculature. Considering the high prevalence of vascular morbidity in SCZ and BD a few studies have examined retinal vascular caliber and have reported increased retinal venular caliber in schizophrenia (SCZ). Retinal vascular tortuosity could serve as a better structural measure than caliber as it is static and less susceptible to pulse period variations. However, to date, no study has examined retinal vascular tortuosity in SCZ and bipolar disorder (BD). Hence, we examined retinal vascular tortuosity in comparison with healthy volunteers (HV). We included 255 subjects (78 HV, 79 SCZ, and 86 BD) in the age range of 18 to 50 years. Trained personnel acquired images using a non-mydriatic fundus camera. To measure the average retinal arteriolar tortuosity index (RATI) and retinal venular tortuosity index (RVTI), we used a previously validated, semi-automatic algorithm. The results showed significant differences across the three groups in RATI but not in RVTI; both BD and SCZ had significantly increased RATI compared to HV. There was also a significant difference between SCZ and BD, with BD having higher RATI. If shown to be of predictive utility in future longitudinal studies, it has the potential to identify patients at risk of development of adverse vascular events. As retinal vascular imaging is non-invasive and inexpensive, it could serve as a proxy marker and window to cerebral vasculature.\u3c/p\u3

Traditional use of medicinal plants by the Jaintia tribes in North Cachar Hills district of Assam, northeast India

The study of ethnobotany relating to any tribe is in itself a very intricate or convoluted process. This paper documents the traditional knowledge of medicinal plants that are in use by the indigenous Jaintia tribes residing in few isolated pockets of northeast India. The present study was done through structured questionnaires in consultations with the tribal practitioners and has resulted in the documentation of 39 medicinal plant species belonging to 27 families and 35 genera. For curing diverse form of ailments, the use of aboveground plant parts was higher (76.59%) than the underground plant parts (23.41%). Of the aboveground plant parts, leaf was used in the majority of cases (23 species), followed by fruit (4). Different underground plant forms such as root, tuber, rhizome, bulb and pseudo-bulb were also found to be in use by the Jaintia tribe as a medicine. Altogether, 30 types of ailments have been reported to be cured by using these 39 medicinal plant species. The study thus underlines the potentials of the ethnobotanical research and the need for the documentation of traditional ecological knowledge pertaining to the medicinal plant utilization for the greater benefit of mankind

Mycobacterium tuberculosis acg Gene Is Required for Growth and Virulence In Vivo

Mycobacterium tuberculosis dosRS two-component regulatory system controls transcription of approximately 50 genes including hspX, acg and Rv2030c, in response to hypoxia and nitric oxide conditions and within macrophages and mice. The hspX lies between acg and Rv2030c. However, the functions of the dosR regulated genes in vitro and in vivo are largely unknown. Previously, we demonstrated that deletion of hspX gene produced a mutant which grew faster in macrophages and in mice. In this study, we attempted to determine the functions of acg and Rv2030c by gene inactivation. We demonstrate that Rv2030c is dispensable for virulence and growth. However, deletion of acg produced a mutant which is attenuated in both resting and activated macrophages and in acute and persistent murine infection models. Surprisingly, deletion of acg did not compromise the viability of the mutant to nitrosative and oxidative stresses in vitro and in vivo. In addition, when the WT and the acg mutants were treated with antibiotics such as the prodrugs nitrofurantoin and nitrofuran, the acg mutant became more sensitive than the WT strain to these drugs. This suggests that Acg may not function as a nitroreductase. These data indicate that acg encodes an essential virulence factor for M. tuberculosis and enables it to grow and survive in macrophages and in mouse organs

The chemical behaviour of sulphur compounds. Part III. Kinetics of the gaseous reaction between hydrogen sulphide and sulphur dioxide

Certain sulphides, in presence of a small amount of moisture were found to catalyse the reaction between hydrogen sulphide and sulphur dioxide. The kinetics of this reaction was studied in a closed system, using an all-glass, gas circulation pump. The partial pressure of water in the reacting system was maintained constant with the aid of a hygrostat [mixture of a hydrated salt and its anhydrous form (or lower hydrate)]. The higher the partial pressure of water, the greater was the velocity of reaction, for a given catalyst. Of the sulphides employed, cobalt thiomolybdate was found to be the best catalyst. Cobalt sulphide and molybdenum sulphide were less efficient. Next in order of efficiency, was silver sulphide. Boron trifluoride and anhydrous aluminium chloride were found to have no catalytic effect on the union between hydrogen sulphide and sulphur dioxide. The mechanism of the reaction could be explained on the basis of the formation of thiosulphurous acid, as the primary product

Oxidation by chloramine-T. Part I. Reaction between hydrogen sulphide and chloramine-T

This article does not have an abstract