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Department of Chemistry, Ravishankar University, Raipur-492 010 Manuscript received 15 June 1987, revised 21 December 1987, accepted 30 December 1987 FLUORIDES occur in the industrial effluents1 and also in water flowing over fluoride-containing rocks and minerals. The TLV (threshold limit value) as recommended by the American Conference of Governmental lndustrial Hygienists is 3 ppm in drinking water2. The toxic effects of excess fluorides are well established2,3.

Chemistry Department, Government Arts and Science College, Durg, India School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur-492 010, India Manuscript received 3 May 2001, revised 24 September 2001, accepted 28 December 2001 A sensitive spectrophotometric method has been developed for the determination of benzene based on nitration of benzene to 1,3-dinitrobenzene and its subsequent reduction to 1,3-phenylenediamine. The 1,3-phenylenediamine so formed is determined by diazotization-coupling reaction using 1,3,5-trihydroxybenzene as coupling agent. The yellow orange azo dye formed in alkaline medium is measured spectrophotometrically at 415 nm. Beer's law is obeyed at 0.2-2.0 ppm benzene. The molar absorptivity is 3.07 x 104 dm3 mo-1 cm-1• The standard deviation and relative standard deviation are ±0.01 and 1.62%, respectively, for 40 µg of benzene per 25 ml analyzed over 7 days. The method may be used to determine benzene in petrol vapour, coke oven effluent and cigarette smoke.

The study compares the steady state creep response of rotating Al-SiC discs having constant, linear, hyperbolic and exponential thickness with different thickness profiles. All the discs are assumed to have equal volume with the same average thickness. The creep behaviour of the disc material is described by threshold stress based law while the yielding is assumed to follow Tresca criterion. The variable thickness disc is observed to have superior creep response, expressed in terms of stresses and strain rates, to a constant thickness disc. Amongst variable thickness discs, the creep response is observed to be superior for linear thickness disc, when the inner thickness of all the discs is kept the same. However, for the same outer thickness, the disc having hyperbolic thickness profile exhibits the best creep response.

Berberine is an alkaloid with a wide range of reported beneficial health effects. The current work provides an extensive literature analysis on berberine. Bibliometric data were identified by means of the search string TOPIC=(berberin* OR umbellatine*), which yielded 5,547 publications indexed in the Web of Science Core Collection electronic database. The VOSviewer software generated bubble maps to visualize semantic terms with citation results. The ratio of original articles to reviews was 13.6:1. The literature has been growing more quickly since the 2010s. Major contributing countries were China, the United States, India, Japan, and South Korea. Most of the publications appeared in journals specialized in pharmacology pharmacy, biochemistry molecular biology, chemistry, and plant science. Some of the frequently mentioned chemicals/chemical classes were alkaloid, palmatine, jatrorrhizine, coptisine, isoquinoline, and sanguinarine. The prevalent medical conditions under investigation included Alzheimers disease, cancer, diabetes, and obesity. ; Acknowledge the support by the Polish KNOW (LeadingNational Research Centre) Scientific Consortium "Healthy Animal-Safe Food," decision of Ministry of Science and Higher Education No. 05-1/KNOW2/2015 and the European Union under the European Regional Development Fund (Homing/2017-4/41). Antoni Sureda has been supported by the Institute of Health Carlos III (Project CIBEROBN CB12/03/30038). Joanna Feder-Kubis was financed by the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Wrocław University of Science and Technology. ...

Resveratrol is a stilbene-type bioactive molecule with a broad spectrum of reported biological effects. In this sense, the current work provides a comprehensive literature analysis on resveratrol, representing a highly-researched commercially available dietary ingredient. Bibliometric data were identified by means of the search string TOPIC=(resveratrol*) and analyzed with the VOSviewer software, which yielded 17,561 publications extracted from the Web of Science Core Collection electronic database. The ratio of original articles to reviews was 9.5:1. More than half of the overall manuscripts have been published since 2013. Major contributing countries were USA, China, Italy, South Korea, and Spain. Most of the publications appeared in journals specialized in biochemistry and molecular biology, pharmacology and pharmacy, food science technology, cell biology, or oncology. The phytochemicals or phytochemical classes that were frequently mentioned in the keywords of analyzed publications included, in descending order: resveratrol, trans-resveratrol, polyphenols, flavonoids, quercetin, stilbenes, curcumin, piceatannol, cis-resveratrol, and anthocyanins. ; Atanas G. Atanasov and Dongdong Wang acknowledge the support by the Polish KNOW (Leading National Research Centre) Scientific Consortium "Healthy Animal - Safe Food," decision of Ministry of Science and Higher Education No. 05-1/KNOW2/2015 and the European Union under the European Regional Development Fund (Homing/2017-4/41). Antoni Sureda was supported by the Institute of Health Carlos III (Project CIBEROBN CB12/03/30038). ...