Synthesis and Biocidal Activity of Organophosphates Derived from Benzothiazole

The synthesis, biocidal activity, and spectroscopic data of a new series of S-phosphorylated/thiophosphorylated derivatives of 2-(2′-mercaptophenyl) benzothiazole are reported in this study. Derivatives were prepared by reacting 2-(2′-mercaptophenyl) benzothiazole with phosphorus oxychloride/phosphorus thiochloride in different molar ratios [1:1, 2:1, 3:1]. All of the derivatives were found to be antifungal agents with less toxicity than the standard Dithane M-45.     

Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions (¹⁹⁶Hg, ¹⁹⁸Hg, ²⁰²Hg, ²⁰⁴Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope ²⁰⁴Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m³ for benzene) level, the interference from SO₂, NO₂, O₃, H₂S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m³ at 1 s averaging and 0.1 mg/m³ at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified.     

A Textile Dressing for Temporal and Dosage Controlled Drug Delivery

Chronic wounds do not heal in an orderly fashion in part due to the lack of timely release of biological factors essential for healing. Topical administration of various therapeutic factors at different stages is shown to enhance the healing rate of chronic wounds. Developing a wound dressing that can deliver biomolecules with a predetermined spatial and temporal pattern would be beneficial for effective treatment of chronic wounds. Here, an actively controlled wound dressing is fabricated using composite fibers with a core electrical heater covered by a layer of hydrogel containing thermoresponsive drug carriers. The fibers are loaded with different drugs and biological factors and are then assembled using textile processes to create a flexible and wearable wound dressing. These fibers can be individually addressed to enable on‐demand release of different drugs with a controlled temporal profile. Here, the effectiveness of the engineered dressing for on‐demand release of antibiotics and vascular endothelial growth factor (VEGF) is demonstrated for eliminating bacterial infection and inducing angiogenesis in vitro. The effectiveness of the VEGF release on improving healing rate is also demonstrated in a murine model of diabetic wounds.     

Physicochemical aspects of <Emphasis Type="Italic">Trichosporon cutaneum</Emphasis> CCY 30-5-10 adhesion and biofilm formation potential on cellophane

This paper focuses on the adhesion and biofilm formation potential of cellulolytic yeast Trichosporon cutaneum CCY 30-5-10 on solid cellophane from a novel perspective. First, physicochemical characterisation of the cells and carrier (cellophane) was performed to evaluate the effect of different culture media (complex vs mineral) on yeast cell adhesion. (Un)favourable adhesion conditions were predicted using the thermodynamic approach. Next, the ability of the cells to colonise the carrier under the above conditions was quantified and the biofilm structure was characterised using image analysis. The approaches described were found suitable to predict and experimentally verify favourable (cell-solid) adhesion, i.e. the hydrophobic and low electron-donor nature of cellophane together with hydrophobic cells (obtained when cultivated in a complex culture medium) were found to have a major impact in defining successful yeast adhesion with subsequent biofilm formation.     

Identification of the aromatic hydroxylamine group by mass spectrometry

The mass spectra of aromatic hydroxylamines are diagnostic; [M], [M – 2], [M – 16] and, in most instances, [M – 17] ions are observed.     

The investigation of sensing mechanism of ethanol vapour in polymer-nanostructured carbon composite

Polymer-nanostructured carbon composites (PNCC) using three different polymers as composite matrix materials (polyvinylacetate (PVAc), polyethylene glycol (PEG) and ethylene-vinylacetate copolymer (EVA)) have been developed. High structure carbon black Printex XE2 (Degussa AG) was used as a composites filler. Ethanol vapour sensor-effect of composites was determined as a change of electrical resistance as the composite was held in ethanol vapour for 30 seconds. Reversibility of electrical resistance of PNCC, response stability and repeatability have been measured and compared. The electrical resistance response of EVA-nanostructured carbon composite (EVA-NCC) to ethanol vapour as a function of vinylacetate content in the copolymer has been evaluated. Promising ethanol vapour sensor-effect has been observed for PEG-NCC followed by PVAc-NCC and EVA-NCC.     

Hydrolysis kinetics of the sulfonylurea herbicide Sulfosulfuron

The kinetics of hydrolytic degradation of Sulfosulfuron was investigated to predict the fate of the herbicide in an aqueous environment. The study revealed that the hydrolytic degradation of Sulfosulfuron followed first-order kinetics. The degradation of the herbicide was dependent on pH and temperature. Hydrolysis rate was faster in acidic condition (t _1/2 = 9.24 d at pH 4.0) than alkaline environment (t _1/2 = 14.14 d at pH 9.2). Several fold increase in the degradation rate was found when temperature was increased from 10 ± 1°C (t _1/2 = 518 h) to 50 ± 1°C (t _1/2 = 10 h). Activation energy (E _a) was also calculated as 63.87 KJ mol^?1, which is required for the hydrolytic degradation of the molecule. Both media pH and temperature effects were coupled together and derived a complex equation to estimate the overall effect of these two abiotic factors. The major degradation mechanism of the compound was the breaking of the sulfonylurea bridge yielding corresponding sulfonamide and aminopyrimidine. The possible significance of the results to persistence of the herbicide in the field condition is discussed.     

Studies on Rare Earth Polyphosphate Glasses of the Composition [NaxM(1 − x)/2aGd(1 − x)/2aPO3]n

A fusion technique was used for the preparation of derivatives of the composition [Na _x M_{(1? x)/2a} Gd_{(1? x)/2a} PO₃] _n (where M = bivalent metal like Cu(II), Ca(II), Zn(II), Ni(II), and Mg (II); x = 1/2, 3/4, & 2/3; and a = valency of metal). Composition of these polyphosphate glasses was confirmed by their analyses for metals and phosphorus. The polymeric nature of all polyphosphate glasses was confirmed by the determination of a number average molecular weight (M _n ). The characteristic frequencies in the IR spectra are supportive of the presence of polyphosphate indicative of the polymeric nature of these derivatives. From X-ray diffraction, the amorphous nature of complex polyphosphates has been determined.     

Synthesis and Biological Activity of Some Novel O-Phosphorylated Benzoxazole Derivatives

The phosphorylation of 2-(2′-hydroxyphenyl) benzoxazole has been accomplished with phosphorus oxychloride in a 1:1, 2:1, and 3:1 molar ratio in the presence of a base to yield O-phosphorylated benzoxazole derivatives. Their structures were confirmed by elemental analyses and IR, ¹H NMR, and ³¹P NMR spectral studies. These compounds have been screened for their insecticidal activity against Periplenata americana and were found to be quite active in this respect.