Optical remote measurement of toxic gases.

Enactment of the Clean Air Act Amendments (CAAA) of 1990 has resulted in increased ambient air monitoring needs for industry, some of which may be met efficiently using open-path optical remote sensing techniques. These techniques include Fourier transform spectroscopy, differential optical absorption spectroscopy, laser long-path absorption, differential absorption lidar, and gas cell correlation spectroscopy. With this regulatory impetus, it is an opportune time to consider applying these technologies to the remote and/or path-averaged measurement and monitoring of toxic gases covered by the CAAA. This article reviews the optical remote sensing technology and literature for that application.     

Genotoxicity of chromium in vitro on yeast: Interaction with DNA†

The genotoxicity of chromium chloride was investigated in cells of D₇ strain of Saccharomyces cerevisiae harvested either from logarithmic or stationary growth phase.

A weak induction of mifotic gene conversion and point reverse mutation was obtained when the incubations were performed using phosphate buffer. No genetic effect was observed when the incubations were performed using Tris‐HCl buffer.

The experiments with ⁵¹Cr radiotracer demonstrated that Cr³⁺ ion enters the yeast cells and binds to DNA even if the incubation mixture was performed with Tris HCl buffer. This behaviour could be due to the highest concentration of CrCl₃ that cause some damages to cytoplasmatic membrane.     

Fluoride distribution in groundwater and survey of dental fluorosis among school children in the villages of the Jhajjar District of Haryana,India

Fluoride concentration of groundwater reserves occurs in many places in the world. A critical area for such contamination in India is alluvial soil of the plain region, consisting of five blocks (Jhajjar, Bahadurgarh, Beri, Matanhail, and Sahalawas) of the Jhajjar District adjacent to the National Capital Territory of India, New Delhi. The purpose of this study was to assess the association between water fluoride levels and prevalence of dental fluorosis among school children of the Jhajjar District of Haryana, India. The fluoride content in underground drinking water sources was found to vary in villages. Hence, the villages were categorized as high-fluoride villages (1.52–4.0 mg F/l) and low/normal-fluoride villages (0.30–1.0 mg F/l). The source of dental fluorosis data was school-going children (7–15 years) showing different stages and types of fluorosis who were permanent resident of these villages. The fraction of dental fluorosis-affected children varied from 30% to 94.85% in the high-fluoride villages and from 8.80% to 28.20% in the low/normal-fluoride villages. The results of the present study revealed that there existed a significant positive correlation between fluoride concentration in drinking water and dental fluorosis in high-fluoride villages (r = 0.508; p < 0.001) and insignificant correlation in low-fluoride villages.     

Behavioral aspects of sperm competition in cuttlefish, Sepia officinalis (Sepioidea: Cephalopoda)

Sexual selection studies in cephalopods indicate that sperm competition is a central feature of their mating systems, yet this has not been studied experimentally in any detail. In 1998 we staged 20 matings of the cuttlefish, Sepia officinalis L., in the laboratory. Males rapidly initiated mating in the “head-to-head” position, with no apparent courtship. Mating lasted an average of 10 min (range 7 to 14 min). For the first 6 min (on average 63% of the mating duration), the male flushed strong jets of water directly at the female's buccal membrane, which sometimes resulted in the expulsion of parts of spermatangia placed there in recent matings. Then, in a single discrete movement that lasted an average of only 14 s, the male's modified fourth left arm – the hectocotylus – wrapped around a single large bundle of spermatophores (ca. 150 to 300) and transferred them to the female's buccal membrane. For the remainder of the mating (average 3 min, range 1.5 to 5.0 min), the hectocotylus repeatedly broke the spermatophores open, and manipulated them, so that sperm were released and many spermatangia were attached along the ventral buccal membrane, near the paired seminal receptacles. Approximately 140 spermatangia were attached in rows 3 to 5 deep around the ventral buccal membrane in a single mating; the rest were usually discarded during mating. Histology revealed that each of the seminal receptacles consists of a series of sperm storage bulbs connected by a central duct, which leads to a single pore at the surface of the buccal membrane. Baseline data on sperm motility were obtained, but the mechanism by which sperm enter the seminal receptacle remains unknown. Females seemed to initiate termination of mating, then males guarded their mates temporarily. These results, combined with other recent laboratory experiments, provide evidence that sperm competition may be a major feature of the mating system of S. officinalis. Received: 4 January 1999 / Accepted: 18 May 1999     

Effect of endosulfan on blood glucose

Endosulfan was administered to cats intravenously at different doses. The compound (3 and 4 mg/kg) showed marked rise in blood glucose level after 15 and 30 minutes of treatment with a gradual fall upto 4 hrs. No change in blood glucose was observed at 2.0 mg/kg dose. Adrenalectomy prevented this rise in glucose level.     

Comparative analysis of the structure of carbon materials relevant in combustion

The determination of the structure of carbon materials is an analytical problem that join the research scientific communities involved in the chemical characterization of heavy fuel-derived products (heavy fuel oils, coal-derived fuels, shale oil, etc.) and of carbon materials (polycyclic aromatic compounds, tar, soot) produced in many combustion processes.

The knowledge of the structure of these “difficult” fuels and of the carbon materials produced by incomplete combustion is relevant to research for the best low-environmental impact operation of combustion systems; but an array of many analytical and spectroscopic tools are necessary, and often not sufficient, to attempt the characterization of such complex products and in particular to determine the distribution of molecular masses.

In this paper the size exclusion chromatography using N-methyl-pyrrolidinone as eluent has been applied for the characterization of different carbon materials starting from typical carbon species, commercially available like polyacenaphthylene, carbon black, naphthalene pitch up to combustion products like soot and soot extract collected in fuel-rich combustion systems. Two main fractions were detected, separated and molecular weights (MWs) determined by comparison with polystyrene standards: a first fraction consisted of particles with very large molecular masses (>100 000 u); a second fraction consisted of species in a relatively small MW range (200–600 u). The distribution of these fractions changes in dependence on the carbon sample characteristics.

Fluorescence spectroscopy applied on the fractions separated by size-exclusion chromatography has been used and comparatively interpreted giving indications on the differences and similarities in chemical structure of such different materials.     

The ameliorative effect of kaempferol against CdCl2- mediated renal damage entails activation of Nrf2 and inhibition of NF-kB

Environmental Science and Pollution Research - This study evaluated the nephroprotective effect of kaempferol against cadmium chloride (CdCl2) -induced nephropathy in rats. It also investigated if...     

Evaluation of Saccharomyces cerevisiae strains as probiotic agent with aflatoxin B1 adsorption ability for use in poultry feedstuffs

In this study the aflatoxin B₁ (AFB₁) removal capacity, the tolerance to salivary and gastrointestinal conditions, autoaggregation and coaggregation with pathogenic bacteria of Saccharomyces cerevisiae strains isolated from broiler feces, were evaluated. Only four of twelve isolated strains were identified as Saccharomyces cerevisiae using molecular techniques. The results obtained in AFB₁ binding studies indicated that the amount of AFB₁ removed was both strain and mycotoxin-concentration dependent. Therefore, a theoretical model was applied in order to select the most efficient strain to remove AFB₁ in a wide range of mycotoxin concentration. The results indicated that S. cerevisiae 08 and S. cerevisiae 01 strains were the most efficient microorganisms in the mycotoxin removal. Viability on simulated salivary and gastrointestinal conditions was investigated and S. cerevisiae 08 strain showed the best results, achieving 98% of total survival whereas S. cerevisiae 01 reached only 75%. Autoaggregation and coaggregation assays showed S. cerevisiae 08 as the most appropriate strain, mainly because it was the unique strain able to coaggregate with the four bacterial pathogens assayed. Consequently, S. cerevisiae 08 is the best candidate for future in vivo studies useful to prevent aflatoxicosis. Further quantitative in vitro and in vivo studies are required to evaluate the real impact of yeast-binding activity on the bioavailability of AFB₁ in poultry. However, this study could be useful in selecting efficient strains in terms of AFB₁ binding and provide an important contribution to research into microorganisms with potential probiotic effects on the host.