Signal transducer and activator of transcription (STAT) 3 is a key signalling protein engaged by a multitude of growth factors and cytokines to elicit diverse biological outcomes including cellular growth, differentiation, and survival. The complete loss of STAT3 is not compatible with life and even partial loss of function mutations lead to debilitating pathologies like hyper IgE syndrome. Conversely, augmented STAT3 activity has been reported in as many as 50% of all human tumours. The dogma of STAT3 activity posits that it is a tyrosine phosphorylated transcription factor which modulates the expression of hundreds of genes. However, the regulation and biological consequences of STAT3 activation are far more complex. In addition to tyrosine phosphorylation, STAT3 is decorated with a plethora of post-translational modifications which regulate STAT3's nuclear function in addition to its non-genomic activities. In addition to these emerging complexities in the biochemical regulation of STAT3 activity, recent studies reveal that STAT3 is either oncogenic or a tumour suppressor. This review will explore these complexities.

p-CuCNS, a three-dimensional polymeric solid with interbonded layers is found to have unusual photoelectrochemical and solid state properties. The material becomes por n-type depending on whether CNS or Cu is in stoichiometric excess. The n-type is found t o be sensitive to the visible spectrum. The methods of preparation of p-and n-type films of p-CuCNS and their photoelectrochemical and solid state properties are discussed.Es wird gefunden, daB B-CuCNS, ein dreidimensionaler polymerer Festkorper mit Interbindungsschichten, ungewohnliche photoelektrochemische und Festkorpereigenschaften besitzt. Das Material wird p-oder n-leitend in Abhangigkeit davon, ob CNS oder Cu im stochiometrischen UberschuB vorliegt. Es wird gefunden, daB die n-leitende Species im sichtbaren Spektrum empfindlich ist.

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BackgroundTea is the most consumed beverage in the world which is second only to water. Tea contains a broad spectrum of active ingredients which are responsible for its health benefits. The composition of constituents extracted to the tea brew depends on the method of preparation for its consumption. The objective of this study was to investigate the extraction kinetics of phenolic compounds, gallic acid, caffeine and catechins and the variation of antioxidant activity with time after tea brew is made.MethodsCTC (Crush, Tear, Curl) tea manufactured in Sri Lanka was used in this study. Tea brew was prepared according to the traditional method by adding boiling water to tea leaves. The samples were collected at different time intervals. Total phenolic and flavonoid contents were determined using Folin ciocalteu and aluminium chloride methods respectively. Gallic acid, caffeine, epicatechin, epigallocatechin gallate were quantified by HPLC/UV method. Antioxidant activity was evaluated by DPPH radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays.ResultsGallic acid, caffeine and catechins were extracted within a very short period. The maximum extractable polyphenols and flavanoids were achieved at 6–8 min after the tea brew is prepared. Polyphenols, flavanoids and epigallocatechin gallate showed a significant correlation (p < 0.001) with the antioxidant activity of tea.ConclusionThe optimum time needed to release tea constituents from CTC tea leaves is 2–8 min after tea is made.

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Hydrogen production through photocatalytic water reduction, a potential path for future renewable and sustainable energy generation.

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