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Enzymatic time–temperature indicators (TTIs) usually suffer from instability and inefficiency in practical use as food quality indicator during storage. The aim of this study was to address the aforementioned problem by immobilizing laccase on electrospun chitosan fibers to increase the stability and minimize the usage of laccase. The addition of NaN3, as and enzyme inhibitor, was intended to extend this laccase TTI coloration rate and activation energy (Ea) range, so as to expand the application range of TTIs for evaluating changes in the quality of foods during storage. A two-component time–temperature indicator was prepared by immobilizing laccase on electrospun chitosan fibers as a TTI film, and by using guaiacol solution as a coloration substrate. The color difference of the innovative laccase TTI was discovered to be &lt, 3, and visually indistinguishable when OD500 reached 3.2, the response reaction time was regarded as the TTI’s coloration endpoint. Enzyme immobilization and the addition of NaN3 increased coloration Km and reduced coloration Vmax. The coloration Vmax decreased to 64% when 0.1 mM NaN3 was added to the TTI, which exhibited noncompetitive inhibition and a slower coloration rate. Coloration hysteresis appeared in the TTI with NaN3, particularly at low temperatures. For TTI coloration, the Ea increased to 29.92–66.39 kJ/mol when 15–25 μg/cm2 of laccase was immobilized, and the endpoint increased to 11.0–199.5 h when 0–0.10 mM NaN3 was added. These modifications expanded the applicability of laccase TTIs in intelligent food packaging.

Metal injection molding (MIM) is a near net-shape manufacturing process combing conventional plastic injection molding and powder metallurgy. Two kinds of injections molds for MIM were developed using conventional mold steel and aluminum (Al)-filled epoxy resins in this study. The characteristics of the mold made by rapid tooling technology (RTT) were evaluated and compared to that fabricated conventional machining method through MIM process. It was found that the service life of the injection mold fabricated by Al-filled epoxy resins is about 1300 molding cycles. The saving in manufacturing cost of an injection mold made by Al-filled epoxy resins is about 30.4% compared to that fabricated conventional mold steel. The saving in manufacturing time of an injection mold made by RT technology is about 30.3% compared to that fabricated conventional machining method.

Coastal waters are polluted by heavy metals to varying degrees, posing potential risks to marine ecology and human health. In May 2006, the pollution levels, sources, and ecological risks of heavy metals (Cu, Pb, Zn, Cd, Hg, and As) in seawater, surface sediments, and living organisms were studied in Jiuzhen Bay in Fujian, China. This study identified Hg (0.26–0.72 µg/L) and As (20.3–31.5 µg/L) pollution in the seawater of Jiuzhen Bay. In sediments, heavy Pb pollution (946 µg/g dw) was only detected at one station at a level posing very serious potential risk, while Hg pollution (0.052–0.087 µg/g dw) was observed at three stations at a level posing serious potential risk. No heavy metal pollution was detected in sediments at other stations. The concentrations of five heavy metals (Cu, Zn, As, Cd, and Pb) exceeded the corresponding National Quality Standards for oysters, indicating heavy pollution, based on an ecological risk assessment. In clams, two heavy metals (Pb and As) exceeded the standards, indicating light pollution, based on an ecological risk assessment. No heavy metal pollution was found in fish or shrimps. The heavy metals in the seawater and sediments of Jiuzhen Bay are mainly derived from the river discharges of Luxi and Wujiang Rivers although sewage discharge along the coast of Jiuzhen Bay is another source of heavy metal pollution at some stations. Given the pollution of Pb, Hg, and As in seawater and sediments at some stations within the bay, the potential risks of Pb, Hg, and As in living organisms to both the marine ecology and human health deserve increased attention.

The horizontal/geographical variations in dissolved dimethylsulfide (DMS), its precursor dimethylsulfoniopropionate (DMSPd and DMSPp), and chlorophyll a (Chl a), as well as the oceanographic parameters influencing the concentrations of dimethylated sulfur compounds, were investigated in the Bering Sea from July to August 2012. Similar to Chl a, the surface DMS and DMSPp levels, as well as DMS(P) production and consumption rates, exhibited a declining gradient from the central basin to the continental shelf, with high-value areas appearing in the central basin, the slope regions, and Anadyr Strait but a low-value area occurring on the outer-middle continental shelf. Considerably high values of DMS and DMSP were measured in the saline Bering Sea Basin Deep Water (>2,000 m) located at the southwest of the Bering Basin because of the release of resuspension in 2,000 m depth and the DMSP production from endogenous benthic bacteria and cyanobacteria population. Chl a was positively correlated with DMSPp and DMS in the surface waters and the upper water of the basin, whereas significant negative correlations were found between DMS and nutrients (dissolved inorganic nitrogen [DIN], phosphorus, and silicate) in the inner shelf of the Bering Sea. DMS microbial consumption was approximately 6.26 times faster than the DMS sea-air exchange, demonstrating that the major loss of DMS in the surface water occurred through biological consumption relative to evasion into the atmosphere. Average sea-to-air DMS fluxes were estimated to be 4.66 μmol/(m2·d), and consequently oceanic biogenic DMS emission had a dominant contribution to the sulfur budget over the observational area.

The spatial and interannual variations of dimethylsulfide (DMS) and its precursors, dissolved and particulate dimethylsulfoniopropionate (DMSP), were discussed on the basis of field observations in the surface waters of the Yellow Sea during spring 2007. Maxima of dimethylated sulfur compounds and low chlorophyll a concentrations were found in the central southern Yellow Sea, whereas low concentrations of DMS and DMSP were detected at the boundary between the northern and southern parts of the Yellow Sea. This frontal region is influenced by active water currents, air–sea interface exchanges, and biological turnover. The horizontal variations in DMS production and consumption rates showed a decreasing tendency from the coastal to offshore areas mainly due to the complicated biological features. DMS positively correlated with dissolved CH4 and CO2 but negatively correlated with nutrients (nitrite and phosphate). Particulate DMSP concentrations and DMS production rates positively correlated with dinoflagellate abundances but negatively correlated with diatom cell densities. DMS and DMSP concentrations, as well as DMS production and consumption rates, exhibited approximately 2.0-2.8 fold increases from 2005 to 2012. This finding was likely caused by shifts in the phytoplankton communities from diatoms to dinoflagellates and the increases in abundances of zooplankton and bacteria. Average sea-to-air DMS fluxes were estimated to be 8.12 ± 1.24 µmol·(m−2·d−1), and DMS microbial consumption was approximately 1.68 times faster than the DMS sea–air exchange. These findings imply that biological consumption, relative to ventilation, is a predominant mechanism in DMS removal from the surface water. This article is protected by copyright. All rights reserved.

Mounting evidence shows that chronic stress can affect both the structure and function of the brain resulting in decreased synaptic plasticity and cognitive dysfunction. Although several studies have indicated that aged brains are more vulnerable to chronic stress, it remains unknown how to prevent stress-induced memory deficits in aged animals. Neuroinflammation plays an important role in the pathogenesis of chronic stress-related brain dysfunction. Receptor-interacting protein 1 (RIP1) is a key molecule that can modulate inflammation, apoptosis, and necroptosis. Here, we investigated whether inhibiting RIP1 using necrostatin-1 during chronic stress could improve chronic stress-related brain dysfunction in D-galactose-induced aging mice. The stressed mice underwent restraint stress for 14 days. Necrostatin-1 (6.25 mg/kg) or vehicle was administered intraperitoneally once every 3 days during the stress period. Locomotor activity was tested using the open field test and cognitive function was assessed using the novel object recognition and Barnes maze tests. The hippocampus was collected to assess neuroinflammation (Iba1, IL-1α, IL-1β, TNF-α, and C1q), necroptosis [RIP1, RIP3, mixed lineage kinase domain-like (MLKL), and NF-κB], neuroplasticity (doublecortin, NR1, NR2A, NR2B, GluA1, and GluA2), and the expression of glucocorticoid and mineralocorticoid receptors. Blood samples were collected to quantify the levels of corticosterone. We found that chronic stress induced obvious memory impairment and neuroinflammation, decreased neurogenesis and GluA2 expression, and increased the expression of RIP1 and NF-κB. Inhibiting RIP1 by necrostatin-1 during chronic stress rescued the memory impairment and alleviated the pathological changes induced by stress. These suggest that inhibiting RIP1 using necrostatin-1 improves chronic stress-related brain dysfunction in D-galactose-induced aging mice. The potential mechanisms include limitation of neuroinflammation and the rescue of neurogenesis and GluA2 expression.

We studied the spatial variations of six volatile halocarbons (VHCs), namely, iodomethane (CH3I), chloroform (CHCl3), tetrachloroethylene (C2Cl4), bromodichloromethane (CHBrCl2), dibromomethane (CH2Br2), and carbon tetrachloride (CCl4), and the environmental influencing factors involved in the cycling of VHCs in the upper ocean (0–500 m) off the Northern Antarctic Peninsula (NAP) during the summer of 2018. About 5%–10% of the total biogenic VHCs in the upper ocean were accumulated in the assemblage layer (AL) with high chlorophyll a. However, higher VHCs levels were observed in the dicothermal layer (DL) compared with the AL because of the preservation from winter and production from dinoflagellates and chlorophytes. Owing to the co-existence occurrence of sharp seasonal pycnocline and thick permanent pycnocline, DL could be an important VHCs reservoir in the upper water column during summer. In response to melting of sea ice and glacier, decreased salinity was responsible for ca. 50% of the variation in the CH2Br2 and CCl4 concentrations, which corresponded with increased CH2Br2 and CCl4 concentrations in the less saline water mass. Anthropogenic CCl4 was found with an average concentration of 44.9 pmol/L, and there was a strong positive relationship between CCl4 and CHCl3 in the upper water, indicating their similar source of pollutant transport caused by anthropogenic activities. Calculated sea-to-air fluxes of CCl4, C2Cl4, CHBrCl2, and CH2Br2 averaged 478.7, 93.7, 33.7, and 61.8 nmol/(m2·d) in summer, respectively, indicating that the waters off the NAP are important sources of VHCs for the atmosphere and exert potentially adverse impacts on the Antarctica ozone depletion.

Blue holes can provide valuable information regarding paleoclimate, climate change, karst processes, marine ecology, and carbonate geochemistry. The Sansha Yongle Blue Hole, located on Yongle Atoll in the Paracel Islands in the South China Sea, is the deepest blue hole in the world. A comprehensive investigation of the blue hole was conducted to determine the hydrochemical properties and associated redox processes active in the water column. Results indicate the presence of two thermoclines, one at 13–20 m and a second at 70–150 m, dividing the water column into five stratified water layers. Based on redox state, the water column can be divided into three layers: an oxic layer in the top 70 m, a chemocline at 70–100 m, which acts as a redox boundary, and an anoxic deep layer. In the oxic layer, photosynthesis in the oxic layer above the seasonal thermocline, results in nutrient uptake, transformation of inorganic carbon to organic carbon in the top mixed layer above the seasonal thermocline; Below the seasonal thermocline, organic matter degradation and nitrification, which are the main biological process at depths around 30 m and 50–70 m, lead to the accumulation of nitrate and a decrease in dissolved oxygen and pH; whereas photosynthesis is dominant at depths of 30–50 m, leading to increase in dissolved oxygen and pH. Within the chemocline, organic matter decays via a variety of reactions (e.g. aerobic mineralization, denitrification and anammox), leading to sharp decreases in the oxidizing chemical species (e.g., dissolved oxygen and nitrate) and corresponding increases in the reduced species (e.g., ammonium and sulfide). Within this layer, about 60% of the nitrogen is lost and chemoautotrophic/photoautotrophic production may contribute significantly to particulate organic carbon. Within the deep anoxic layer, sulfate reduction and degradation of organic matter result in accumulations of sulfide, dissolved inorganic carbon, and nutrients.

In the present work, the successful fabrication of highly sensitive formaldehyde sensor based on ZnO doped Pd and Pt nanoparticles. The Pt-Pt/ZnO has been synthesized through a simple, facile and rapid method and characterized by several techniques. The fabricated Pt-Pt/ZnO exhibited a very high HCHO gas sensor response of 289.2 to 10 ppm, good selectivity and experimental detection limit of 0.5 ppm at room temperature. Response and recovery times for formaldehyde are 96 s and 46 s, respectively, at room temperature. Therefore, Pt-Pt/ZnO is a promising application in the field of detection of formaldehyde.

The concentrations of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and chlorophyll a (Chl-a) as well as the size distribution of particulate DMSP (DMSPp) were determined in the Yellow Sea (YS) and Bohai Sea (BS) during two cruises from 1 to 20 November 2012 and from 21 June to 11 July 2013. Besides, the biological production and consumption rates of DMS and the degradation rates of dissolved DMSP (DMSPd) were also measured. The concentrations of DMS and DMSP showed a significant seasonal variation with higher values in summer, which corresponded well with the seasonal change of Chl-a in the study area. Both DMS and DMSPp concentrations were significantly correlated with Chl-a levels, implying that phytoplankton biomass might play an important role in controlling the distributions of DMS and DMSP in the study area. The size-fractionation research showed that nanophytoplankton (5–20 μm) contributed to most of Chl-a and DMSPp in autumn and summer. The average biological production and consumption rates of DMS during summer were 13.35 and 9.80 nmol L−1 d−1, respectively, which were much higher than those during autumn. The degradation rates of DMSPd during summer ranged from 7.10 to 21.70 nmol L−1 d−1, with an average of 14.71 nmol L−1 d−1, which was nearly equal to the average biological production rate (13.35 nmol L−1 d−1) of DMS. The average sea-to-air flux of DMS in the YS and BS were 12.06 and 20.81 μmol m−2 d−1 in autumn and in summer, respectively, which were much higher than the values reported in the ocean.

A novel, fast, and efficient two-step microextraction technique for preconcentration and extraction of trace amounts of malachite green in fishpond water, river water and flesh of fish was developed using spectrophotometry. MG with a pH of 6.5 was extracted and mediated by the coacervation phase of the anionic surfactant sodium dodecyl benzene sulfonate. The coacervation phase was then trapped by diatomite bonded Fe3O4 magnetic nanoparticles (DBMNPs) that can rapidly achieve two-phase separation in a magnetic field. The extracted surfactant-rich phase was diluted with ethanol and its absorbance was measured at 624 nm. A number of important parameters affecting extraction efficiency, such as the volume of extraction solvent, amount of salt, pH, amount of DBMNPs, equilibration temperature and time, were investigated. The calibration graph was linear for MG ranging from 2 ng mL−1 to 180 ng mL−1 in the initial solution, with r2 = 0.9994 (n = 10). The detection limit based on three times the standard deviation of the blank (3Sb) was 0.67 ng mL−1 and the relative standard deviation for 20 ng mL−1 of MG was 1.12% (n = 5). The method was applied to determine the trace amounts of MG from fishpond water, river water and flesh of fish.

In this paper, a resistance type gas sensor which consists of tungsten oxide (PEDOT:PSS), [Formula: see text] particles and silver finger electrodes was prepared on glass as well as (PET) substrates. The structural and surface morphological properties of the sensors were studied using (XRD), UV-visible, (FTIR), (FE-SEM) and 3D optical microscopy. The influence of fabrication parameters on the sensibility for nitrogen dioxide [Formula: see text] detection is discussed. Experimental results reveal that the sensor with [Formula: see text] content of 2 g/mL shows the highest response rate of 2.31 with increasing concentration up to 80 ppm of nitrogen dioxide gas. The response of the flexible gas sensor reveals improved sensing performance after 500 bending tests.

Nanosized ZnO was prepared successfully by solid phase coordination chemistry reaction and characterized by XRD and TEM techniques. The results of CV testing indicated that the peak shapes in CV diagrams were differed for the three electrodes when the scan rate was 1 mV s-1. The mixture electrode (sample D) that nanosized ZnO additives were 50% exhibited remarkable cyclic reversibility. The results indicated that the optimum ratio of ZnO additives were 50% by means of constant current charge-discharge. The rechargeability of the Zn electrode could be improved. But the nanosized ZnO were more effective in modifying Zn electrode than the common ZnO particles. Its discharge capacity at 25th and 30th charge-discharge cycle achieves 220 mAh g-1and 198 mAh g-1, respectively.

We present a memory property study of floating gate structure embedded with Au–SiO2 core–shell nanoparticles (NPs). Herein, the Au–SiO2 core–shell configuration was readily fabricated by a self-assembly (SAM) layer-by-layer process using 3-aminopropyltrimethoxysilane (APTMS) as a versatile mediator. This functional APTMS served as both a binder for adsorbing colloidal Au NPs onto the substrate and to self-organize a SiO2 ultra-thin shell to cover the Au NP cores. A two-run APTMS SAM process was employed to develop the core–shell configuration. The first-run APTMS formed a well-organized monolayer on the substrate which was responsible for the obtained uniform SAM with high density of Au NPs. Next, the second-run APTMS formed an APTMS bilayer around the Au NPs. During the SAM process, a polymerization process simultaneously occurred with the reaction of neighboring silanol groups to form an Si–O–Si network structure. The polymerization was completed by a 400 °C-annealing to form a SiO2 layer within the APTMS bilayer. In addition, the annealing also resulted in the decomposition of the APTMS and released the preformed SiO2 layer from the APTMS bilayer. The ultra-thin SiO2 layer was flexible enough to cover the Au NP cores, eventually constructing the Au–SiO2 core–shell structure. Compared to Au nanocrystal (NC) memory, Au–SiO2 core–shell NCs show a larger memory window and significantly improved retention performance, which are attributed to the SiO2 shell-induced superior NP/oxide interface qualities and the characteristics of the Au NPs.

The effects of changing salinity and nitrogen limitation on dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) concentrations were investigated in batch cultures of coastal diatom Skeletonema costatum, an ecologically important species. Changes in salinity from 20–32 caused no measurable variation in cell growth or culture yield, but increased intracellular DMSP per cell by 30%. Nitrogen limitation caused up to a two-fold increase in total DMSP per cell and up to a three-fold increase in DMS per cell. These changes in DMSP and DMS per cell in the Skeletonema costatum cultures with nitrogen limitation and changing salinity were primarily attributed to the physiological functions of DMSP as an osmolyte and an antioxidant. The data obtained in this study indicated that nitrogen limitation and salinity may play an important role in climate feedback mechanisms involving biologically derived DMS.

The production of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) by marine microalgae was investigated to elucidate more on the role of marine phytoplankton in ocean-atmosphere interactions in the global biogeochemical sulfur cycle. Axenic laboratory cultures of four marine microalgae-Isochrysis galbana 8701, Pavlova viridis, Platymonas sp. and Chlorella were tested for DMSP production and conversion into DMS. Among these four microalgae, Isochrysis galbana 8701 and Pavlova viridis are two species of Haptophyta, while Chlorella and Platymonas sp. belong to Chlorophyta. The results demonstrate that the four algae can produce various amounts of DMS(P), and their DMS(P) production was species specific. With similar cell size, more DMS was released by Haptophyta than that by Chlorophyta. DMS and dissolved DMSP (DMSPd) concentrations in algal cultures varied significantly during their life cycles. The highest release of DMS appeared in the senescent period for all the four algae. Variations in DMSP concentrations were in strong compliance with variations in algal cell densities during the growing period. A highly significant correlation was observed between the DMS and DMSPd concentrations in algal cultures, and there was a time lag for the variation trend of the DMS concentrations as compared with that of the DMSPd. The consistency of variation patterns of DMS and DMSPd implies that the DMSPd produced by phytoplankton cells has a marked effect on the production of DMS. In the present study, the authors’ results specify the significant contribution of the marine phytoplankton to DMS(P) production and the importance of biological control of DMS concentrations in oceanic water.

Cotton fabric was first oxidized with sodium periodate, and then employed to immobilize catalase. Optimization studies for oxidation of the fabric and immobilization of the enzyme were performed. The properties of the immobilized catalase were examined and compared with those of the free enzyme. A high activity of the immobilized enzyme was obtained when the fabric was oxidized at 40°C and pH 6.0 for 8h in a bath containing 0.20 mol L−1 sodium periodate and the enzyme was immobilized at 4°C for 24h with a catalase dosage of 120.0 U mL−1. The immobilized enzyme exhibited optimum activity at 40°C, while the free enzyme had optimal temperature of 30°C, suggesting that the immobilized catalase could be used in a broader temperature range. Both the immobilized and free enzyme had pH optima of 7.0. The staining test and reusability showed that the catalase was fixed covalently on the oxidized cotton fabric.

In the title complex, C13H11N3O6, it is observed that the very strong NHO [N⋯sO 2.525(2) A] holds the molecules of 3,5-dinitrobenzoic acid and 4-methylpyridine together, and that the hydrogen atom is centered between the hydrogen donor and acceptor in that hydrogen bond. The heterocyclic moiety appears as an intermediate between pyridine and pyridinium, while the benzoic acid between carboxylate and carboxylic group. The title complex is further stabilized by CHO hydrogen bonds and π–π interaction.

Titanium oxide films were synthesized on titanium, cobalt alloy and low-temperature isotropic pryolytic carbon by ion beam enhanced deposition. The non-stoichiometrical titanium oxide films were obtained. Blood compatibility of the films were evaluated by clotting time measurement, platelet adhesion investigation and hemolysis analyses. The results revealed that blood compatibility of the materials was improved by the coating of titanium oxide films. Semiconductor nature of non-stoichiometric titanium oxide films might be responsible for the improvement of blood compatibility.

In the title compound, [CuCl2(C9H12N2O)], the Cu(II) atom is coordinated by two Cl- anions and two N atoms of one O-ethyl 3-methylpyridine-2-carboximidic acid molecule in a slightly distorted square-planar geometry, with Cu-N distances of 2.0483 (17) and 1.9404 (18) A, and Cu-Cl distances of 2.2805 (10) and 2.2275 (14) A. In addition, each Cu(II) atom is connected by one Cl- anion and the Cu(II) atom from a neighbouring molecule, with Cu...Cl and Cu...Cu distances of 2.9098 (13) and 3.4022 (12) A, respectively, and, therefore, a centrosymmetric dimer is formed. Adjacent molecular dimers are connected by pi-pi stacking interactions between pyridine rings to form a zigzag molecular chain. The molecular chains are also enforced by N-H...Cl and C-H...Cl interactions.

Environmental context DMSP is one of the most important substrates for marine bacteria and its cycling contributes substantially to fluxes of carbon and sulfur in the ocean. Accurate determination of the concentration of DMSP available to bacteria is essential to quantifying DMSP consumption rates, and this work improves those determinations by identifying non-bioavailable pools of DMSP that have previously gone unrecognised. Improved estimates of DMSP consumption rates will lead to better understanding of its role in ocean food web and biogeochemical dynamics. Abstract Dissolved dimethylsulfoniopropionate (DMSPd) is an important substrate for marine microbes and a precursor of sulfur gases. We compared DMSPd turnover flux rates in coastal seawater measured with a 35S-DMSPd tracer to those obtained with the DMSP-uptake inhibitor glycine betaine (GBT). The 35S-DMSP tracer method yielded DMSPd turnover fluxes (35.7–215nM day–1) that were 1.7 to 152 times higher than those obtained in parallel samples with the GBT inhibitor method (0.34–21.6nM day–1). Tests confirmed that GBT functioned as planned by strongly inhibiting DMSPd degradation and that 35S-DMSPd gave accurate estimates of DMSPd loss rate constants. This left the initial DMSPd concentrations, determined by small volume drip filtration (SVDF) through Whatman GF/F filters (0.7-μm nominal retention) ([DMSPd]SVDF), as a potential cause of the discrepancy in rate estimates. Indeed, GF/F filtrate incubations showed that the initial [DMSPd]SVDF overestimated the bioavailable DMSPd concentrations for at least two reasons: (1) a significant fraction (10–37%) of DMSP passing through GF/F filters was in particles >0.2μm (likely bacteria) and therefore not dissolved, and (2) a significant pool (0.44–1.0nM) of operationally dissolved, non-particle DMSP ([DMSPd]

A novel and simple rapid shaking-based method of ionic liquid dispersive liquid phase microextraction for the determination of six synthetic food colourants (Tartrazine, Amaranth, Sunset Yellow, Allura Red, Ponceau 4R, and Erythrosine) in soft drinks, sugar- and gelatin-based confectionery was established. High-performance liquid chromatography coupled with an ultraviolet detector was used for the determinations. The extraction procedure did not require a dispersive solvent, heat, ultrasonication, or additional chemical reagents. 1-Octyl-3-methylimidazolium tetrafluoroborate ([C8MIM][BF4]) was dispersed in an aqueous sample solution as fine droplets by manual shaking, enabling the easier migration of analytes into the ionic liquid phase. Factors such as the [C8MIM][BF4] volume, sample pH, extraction time, and centrifugation time were investigated. Under the optimum experimental conditions, the proposed method showed excellent detection sensitivity with limits of detection (signal-to-noise ratio = 3) within 0.015–0.32 ng/mL. The method was also successfully used in analysing real food samples. Good spiked recoveries from 95.8%–104.5% were obtained.

The title compound, [ZnIICl2(C4H6N2O)2], is built up from two isoxazole rings and two Cl atoms in a tetrahedral arrangement around the Zn atom. There are intramolecular N—H⋯Cl hydrogen bonds. Infinite supramolecular chains, formed by N—H⋯Cl intermolecular hydrogen bonds, are associated further with each other by π–π interactions between the anti-parallel isoxazole rings.

An experimental animal model has been established using i.v. fat injection to mimic fat embolism syndrome (FES). Fourteen healthy mongrel dogs who were administered 0.7 ml/kg of fluid marrow fat obtained from the long bone marrow cavity of mongrel dogs were divided into control and therapeutic groups. The therapeutic group (n = 7) was given dexamethasone (1.0 mg/kg) and repeated every 6 h i.v. During 48 h of observation, blood gas analysis and frozen sections were performed on blood samples collected from the pulmonary vessels by a floating catheter and from a peripheral vein at different time intervals. The frozen sections were stained with Oil Red O. Positive results were seen 2 h after fat injection in both pulmonary and peripheral blood samples of both control and therapeutic groups. By computer image analysis, the average median number of fat droplets per section and the average median diameter of fat droplets in pulmonary blood of the control group were found to be significantly higher and larger than were those of the therapeutic group. The average median number and diameter of fat droplets in pulmonary blood were significantly higher and larger than were those of peripheral blood in both control and therapeutic groups. These findings correlated well with blood gas changes and the clinical appearance of the experimental animals. The fat droplets from pulmonary or peripheral blood as demonstrated by Oil Red O staining in combination with blood gases changes [PaO27.99 KPa, difference between the alveolar and arterial oxygen tension (P(A - a)O2)6.09 KPa] may be a rapid method for screening of an earlier diagnosis of FES.(ABSTRACT TRUNCATED AT 250 WORDS)

The crystal structure of the dodecamer, d(CGCIAATTCGCG), has been determined at 2.4 A resolution by molecular replacement, and refined to an R-factor of 0.174. The structure is isomorphous with that of the B-DNA dodecamer, d(CGCGAATTCGCG), in space group P2(1)2(1)2(1) with cell dimensions of a = 24.9, b = 40.4, and c = 66.4 A. The initial difference Fourier maps clearly indicated the presence of inosine instead of guanine. The structure was refined with 44 water molecules, and compared to the parent dodecamer. Overall the two structures are very similar, and the I:C forms Watson-Crick base pairs with similar hydrogen bond geometry to the G:C base pairs. The propeller twist angle is low for I4:C21 and relatively high for the I16:C9 base pair (-3.2 degrees compared to -23.0 degrees), and the buckle angles alter, probably due to differences in the contacts with symmetry related molecules in the crystal lattice. The central base pairs of d(CGCIAATTCGCG) show the large propeller twist angles, and the narrow minor groove that characterize A-tract DNA, although I:C base pairs cannot form the major groove bifurcated hydrogen bonds that are possible for A:T base pairs.