Measurement of radon concentration and assessment of associated cancer risk in some fertilizer warehouses in the Punjab province of Pakistan

Radon concentration was measured by using ³⁹CR track etched detectors in five fertilizer warehouses in the Punjab province of Pakistan. The average concentration of radon was determined to be 20–88 Bq m⁻³. Annual effective dose (AED) and excess lifetime cancer risk (ELCR) have also been assessed using the models of UNSCEAR and ICRP. The corresponding annual dose and ELCR to the workers of warehouses have been estimated to be 0.30–1.02 mSv year⁻¹ and 0.44–1.02%, respectively.

     

Synthesis of Highly Potent Anti-Inflammatory Compounds (ROS Inhibitors) from Isonicotinic Acid

In search of anti-inflammatory compounds, novel scaffolds containing isonicotinoyl motif were synthesized via an efficient strategy. The compounds were screened for their in vitro anti-inflammatory activity. Remarkably high activities were observed for isonicotinates 5–6 and 8a–8b. The compound 5 exhibits an exceptional IC₅₀ value (1.42 ± 0.1 µg/mL) with 95.9% inhibition at 25 µg/mL, which is eight folds better than the standard drug ibuprofen (11.2 ± 1.9 µg/mL). To gain an insight into the mode of action of anti-inflammatory compounds, molecular docking studies were also performed. Decisively, further development and fine tuning of these isonicotinates based scaffolds for the treatment of various aberrations is still a wide-open field of research.     

The Adsorption of Herbicides and Pesticides on Clay Minerals and Soils. Part 2. Atrazine

The adsorption of atrazine and two model compounds,2-chloropyrimidine and 3-chloropyridine on clay minerals(bentonite, montmorillonite and kaolinite), organic matter (humic acid) and soil (with and without organic matter) has beenstudied using FT-infrared spectroscopy (IR), thermogravimetric analysis (TGA), high pressureliquid chromatography (HPLC) and X-ray diffraction (XRD).3-Chloropyridine, 2-chloropyrimidine and atrazine were adsorbedthrough hydrogen bonding on bentonite, montmorillonite, humic acid and soil. In addition tohydrogen bonding, protonation of 3-chloropyridine and atrazine was also observed.In the adsorption of 2-chloropyrimidine on bentonite and montmorillonitean ion exchange mechanism also occurred. No adsorption of 3-chloropyridine or 2-chloropyrimidine wasobserved on the kaolinite clay mineral.Both the clay minerals and organic matter of soil contribute tothe adsorption of organic compounds on soil but the clay minerals bentonite and montmorilloniteplay a major role in their adsorption on soil.     

A Novel Spectrophotometric Method for the Determination of Zolmitriptan in Pharmaceutical Formulations

A simple, rapid, cost effective and extraction‐free spectrophotometric method has been developed for the determination of zolmitriptan in pharmaceutical raw and dosage forms. The method is based on the charge‐transfer reaction of zolmitriptan in acetonitrile medium with 0.2% 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone to form a colored product peaking at 555 nm. Beer's law is obeyed in the concentration range 10‐250 μg mL^?1 with molar absorptivity of 1.7 × 10³ L mole^?1 cm^?1. The effects of variables such as reagent concentration, time of reaction, color stability and interferences have been investigated to optimize the procedure. The results have been validated analytically and statistically. The proposed method has been successfully applied for the determination of zolmitriptan in pharmaceutical formulations. Results indicate that the method is accurate, precise and reproducible (relative standard deviation < 2%).     

Chemical synthesis of zinc oxide nanorods for enhanced hydrogen gas sensing

Zinc oxide(ZnO) nanorods are prepared using equimolar solution of zinc nitrate((Zn(NO3)2) and hexamethylenetetramine(C6H12N4) by the hydrothermal technique at 80 C for 12 h. Epitaxial growth is explored by X-ray diffraction(XRD) patterns, revealing that the ZnO nanorods have a hexagonal(wurtzite) structure. Absorption spectra of ZnO are measured by UV–visible spectrometer. The surface morphology is investigated by field emission scanning electron microscopy(FESEM). The synthesized ZnO nanorods are used for detecting the 150 C hydrogen gas with a concentration over 1000 ppm. The obtained results show a reversible response. The influence of operating temperature on hydrogen gas detecting characteristic of ZnO nanorods is also investigated.     

Growth by molecular beam epitaxy and electrical characterization of GaAs nanowires

We report on structural and electrical properties of GaAs nanowires (NWs) grown by molecular beam epitaxy (MBE) on GaAs and SiO₂ substrates using Au as growth catalyst. Au–Ga particles are observed on the top of the NWs by transmission electron microscopy (TEM). In most of the observed cases, individual particles contain two Au–Ga compositions, in particular orthorhombic AuGa and β′ hexagonal Au₇Ga₂. The wires grown on GaAs are regularly shaped and tidily oriented on both (1 0 0) and (1 1 1)B substrates. TEM also reveals that the NWs have a wurtzite lattice structure. Electrical transport measurements indicate that nominally undoped NWs are weakly n-type while both Be- and Si-doped wires show p-type behaviour. The effect of the lattice structure on impurity incorporation is briefly discussed.     

Probing the stereoselectivity of P-glycoprotein-synthesis, biological activity and ligand docking studies of a set of enantiopure benzopyrano[3,4-b][1,4]oxazines

A series of enantiomerically pure benzopyrano[3,4-b][1,4]oxazines have been synthesised and tested for their ability to inhibit P-glycoprotein. Reducing the conformational flexibility of the molecules leads to remarkable differences in the activity of diastereoisomers. Docking studies into a homology model of human P-gp provide first insights into potential binding areas for these compounds.     

Analysis and experiment of all-optical time-interleaved multi-channel regeneration based on higher-order four-wave mixing in a fiber

Simultaneous all-optical multi-channel regeneration based on second-order four-wave mixing (FWM) in a single highly nonlinear fiber (HNLF) is studied. Interchannel crosstalk, especially cross gain saturation and generation of interchannel FWM, is avoided by properly time-interleaved channels. Preliminary experiment of 2 ch × 10 Gbit/s operation shows simultaneous noise reduction of the two channels and good agreement with numerical analysis. Numerical investigation on 2 ch × 40 Gbit/s operation using the same parameters as the experiment shows that the regeneration can improve qualities of both channels. For more number of channels and higher speed of operation, several parameters need to be adjusted to avoid interchannel crosstalks. Time synchronization techniques for the input channels are also discussed.     

Seimatoric acid and colletonoic acid:Two new compounds from the endophytic fungi,Seimatosporium sp.and Colletotrichum sp.

A new metabolite,named seimatoric acid(1),representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz.,2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone(2),(-)-phyllostine(3),(+)-epiepoxydon(4) and(+)-epoxydon monoacetate(5).Similarly one new benzoic acid derivative,named colletonoic acid(6) was isolated from the ethyl acetate fraction of Colletotrichum sp.The structures of the new compounds were elucidated by detailed ~1 H NMR,~(13)C NMR,COSY,HMQC.HMBC spectroscopic analysis,and HR-E1-MS.Seimatoric acid(1)was also isolated from another taxonomical unidentified fungal strain 4295 in ourgroup.The structures of the known compounds were elucidated by their spectral data comparison to literature data.Preliminary studies showed that colletonoic acid(6) showed good antibacterial,antifungal,and antialgal activities.