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Spectrophotometric Determination of Thiosulfate in Desulfurization Solutions by Decoloration of Methylene Blue Published on: May 1, 2023 Xiuxiu Zhao, Ming Xu, Chunying Ma, Yingying Ma, Xianji Ma Spectroscopy, May 2023, Volume 38, Issue 5 Pages: 19–22,34 This article proposes a method for the determination of thiosulfate by decoloring spectrophotometry with methylene blue as an oxidant. Methylene blue has redox properties. Its oxidized form is blue, and its reduced form is colorless. Thiosulfate is a medium-strength reducing agent. In an acidic medium, the two can undergo redox reactions to reduce methylene blue and cause the solution to exhibit a fading reaction within a certain range, and the degree of fading is proportional to the amount of thiosulfate added. This method measures the change in absorbance (AU) at a fixed wavelength of 664 nm, and ΔAU has a linear relationship with the content of thiosulfate. The linear range is 0–0.3 mmol/L. From this curve, the content of thiosulfate in the desulfurization solution can be accurately measured. This method is not interfered with by other secondary salts in the desulfurization solution during the thiosulfate determination process, and has high sensitivity. The color change can be observed by the naked eye to judge whether there is thiosulfate in the solution. This method is simple to perform and is an improved method for the determination of thiosulfate in a desulfurization solution.

Ammonium sulfate and ammonium chloride are widely used in daily production and life. They can be used as nitrogen fertilizer in agricultural fields and as raw materials for other chemical products in factories. Under the action of precipitation and other factors, these compounds can have a certain impact on water ecology when they enter natural water bodies. In the paper, the acute toxicity of ammonium sulfate and ammonium chloride was investigated using water fleas as indicator organisms. According to GB/T 16125- 2012 test method for acute toxicity of water flea, the 24h-LC50 values of the acute toxicity of ammonium sulfate and ammonium chloride to water flea were 469. 894mg/L and 546. 720mg/L respectively, which were classified as slightly toxic according to the toxicity class.

This study summarizes the recent advances of functional separators for stable aqueous zinc batteries.

Wntless (WLS), an evolutionarily conserved multi-pass transmembrane protein, is essential for secretion of Wnt proteins. Wnt-triggered signaling pathways control many crucial life events, whereas aberrant Wnt signaling is tightly associated with many human diseases including cancers. Here, we report the cryo-EM structure of human WLS in complex with Wnt3a, the most widely studied Wnt, at 2.2 Å resolution. The transmembrane domain of WLS bears a GPCR fold, with a conserved core cavity and a lateral opening. Wnt3a interacts with WLS at multiple interfaces, with the lipid moiety on Wnt3a traversing a hydrophobic tunnel of WLS transmembrane domain and inserting into membrane. A β-hairpin of Wnt3a containing the conserved palmitoleoylation site interacts with WLS extensively, which is crucial for WLS-mediated Wnt secretion. The flexibility of the Wnt3a loop/hairpin regions involved in the multiple binding sites indicates induced fit might happen when Wnts are bound to different binding partners. Our findings provide important insights into the molecular mechanism of Wnt palmitoleoylation, secretion and signaling., The transmembrane protein Wntless (WLS) is essential for the secretion of Wnt proteins, which are signaling molecules of the Wnt signaling pathways. Here, the authors present the 2.2 Å cryo-EM structure of human WLS in complex with Wnt3a and discuss mechanistic implications for the palmitoleoylation of Wnt3a that is required for WLS mediated Wnt secretion.

Tea, which is usually made from the new shoots of tea plants (Camellia sinensis), is one of the most popular and healthy beverages. The tenderness of new shoots plays a critical role in the production of high-quality tea; however, the factors affecting the tenderness of the new shoots of tea have not been extensively studied. Here, we show that cellulose accumulation is negatively correlated with the tenderness of new shoots, including leaves and stems, by characterizing the cellulose content and visualizing cellulose in the new shoots of two cultivars ("Huangjinya" and "Yujinxiang") via toluidine blue staining. We further found that the number of cells with secondary cell walls (SCWs) and the thickness of SCWs increased with the maturity degree of stems in both cultivars. Because cellulose is the most abundant polymer in SCW, we next identified three cellulose synthase CsCesAs, CsCesA4, 7, and 8A, through homologous alignment with Arabidopsis AtCesAs. Protein sequence analysis revealed that these proteins were closely related based on the phylogenetic analysis. We finally showed that the gene expression of the three CsCesAs was positively correlated with the maturity degree and cellulose content of the new shoots. Thus, our data suggest that cellulose accumulation, especially in the SCWs, is negatively correlated with the tenderness of new shoots in tea plants.

‘Huangjinya’ is a novel light-sensitive albino tea cultivar. Previously we have found that the leaves exhibit varying degrees of yellow coloration after being exposed to different light qualities, including red light (RL), blue light (BL), red + blue light (RB) and white light (WL). To understand the transcriptional response of different light qualities in leaf coloration of ‘Huangjinya’, RNA-seq analysis with three biological replicates was performed to identify differentially expressed genes (DEGs) involved in pigment metabolism pathways. With regard to porphyrin and chlorophyll metabolism, the protochlorophyllide oxidoreductase (POR) was upregulated and chlorophyllase (Chlase) was downregulated under RL compared with WL, which contributed to high chlorophyll content in ‘Huangjinya’. The upregulated POR and magnesium chelatase H subunit (CHLH) were identified under RB. BL significantly promoted carotenoid biosynthesis, accompanied by the related upregulated genes. However, upregulated xanthoxin dehydrogenase (ABA2) reduced carotenoid content under BL. Zeaxanthin epoxidase (ZEP) was upregulated and ABA2 was downregulated under RB, resulting in high accumulation of carotenoid content. BL and RL upregulated expressions of genes involved in flavonoid biosynthesis in ‘Huangjinya’. Differential expressions of genes involved in flavonoid biosynthesis was considered as the results of leaf color change. In addition, the genes related to photosynthesis were downregulated under RL, whereas these were upregulated under BL when compared with WL. In conclusion, the effect of light quality on the leaf coloration of ‘Huangjinya’ was mainly dependent on chlorophyll content by altering corresponding genes expressions. RL may promote the accumulation of chlorophyll in ‘Huangjinya’ leaves by upregulating the expression of genes related to chlorophyll synthesis (e.g., POR) and downregulating expression of genes related to chlorophyll degradation (e.g., Chlase). BL could upregulate the expression of genes related to both biosynthesis (e.g., POR, hemA) and degradation (e.g., Chlase) of chlorophyll, resulting in little change in leaf color of ‘Huangjinya’ under blue light when compared with white light. Upregulated genes involved in chlorophyll biosynthesis (e.g., POR, CHLH) induced greener color of ‘Huangjinya’ treated with RB.

The purpose of this study is to investigate the effect of coil structure on electromagnetic fields and temperature distributions of copper–steel tube induction brazing for compressor-automatic production line. To get a satisfied temperature distribution, five coil structures were designed and three-dimensional finite element models were established. The temperature distribution of the workpiece was numerically predicted and compared with the experimental values, and the simulated temperature field shows very good agreement with the experimental temperature measurements on the workpiece surface. The simulated results revealed that the coil structure was crucial and considerable to the thermal field of the workpiece and heating efficiency. Moreover, different materials have large differences in temperature change when heated by the same coil. To ensure good quality of the joints and high productivity, a reasonable heating time of rapid induction brazing was obtained at about 4 s. The comparison results indicated that the coil structure of square ring with series connection demonstrated the highest performance in terms of heating efficiency and energy usage among the coil designs.

Dimethylsulfoniopropionate (DMSP) is an important marine osmolyte. Aphotic environments are only recently being considered as potential contributors to global DMSP production. Here, our Mariana Trench study reveals a typical seawater DMSP/dimethylsulfide (DMS) profile, with highest concentrations in the euphotic zone and decreased but consistent levels below. The genetic potential for bacterial DMSP synthesis via the dsyB gene and its transcription is greater in the deep ocean, and is highest in the sediment.s DMSP catabolic potential is present throughout the trench waters, but is less prominent below 8000 m, perhaps indicating a preference to store DMSP in the deep for stress protection. Deep ocean bacterial isolates show enhanced DMSP production under increased hydrostatic pressure. Furthermore, bacterial dsyB mutants are less tolerant of deep ocean pressures than wild-type strains. Thus, we propose a physiological function for DMSP in hydrostatic pressure protection, and that bacteria are key DMSP producers in deep seawater and sediment., Dimethylsulfoniopropionate (DMSP) is an osmolyte produced by marine microbes that plays an important role in nutrient cycling and atmospheric chemistry. Here the authors go to the Mariana Trench—the deepest point in the ocean—and find bacteria are key DMSP producers, and that DMSP has a role in protection against high pressure.

Alanine contributes to the taste and nutritional quality of tea and is an important member of alanine metabolism catalyzed by alanine aminotransferase (AlaAT, EC 2.6.1.2). However, the molecular mechanism underlying alanine metabolism in tea plants has not been fully elucidated. In this study, an increase in enzyme activity of AlaAT2 was detected in vitro, and the alanine aminotransferase activity was higher level in leaves than that in other tissues of tea plant, while the CsAlaAT2 transcription was high in leaves and root. Using phylogenetic analysis, an alanine aminotransferase gene CsAlaAT2 was identified as a member of group C, which was located in the mitochondrion. Additionally, the molecular mass of CsAlaAT2 protein was found to be approximately 53 kDa by SDS-PAGE and western blotting. The CsAlaAT2 expression level and the alanine content in photosynthetic tissues increased in response to the shade treatment. Furthermore, the involvement of CsAlaAT2 in alanine biosynthesis was confirmed based on transient suppression assays in tea leaves, and the alanine content and CsAlaAT2 transcript level decreased when CsAlaAT2 expression was suppressed in tea leaves. Thus, this study suggests that CsAlaAT2 is essential for the alanine metabolism in tea plants grown and its response to shade.

The purpose of this study is to investigate the effect of welding residual stress on operating stress in designing a nuclear turbine welded rotor. A two-dimensional axisymmetric finite element model is employed to calculate the residual stress before and after post weld heat treatment (PWHT), and then the superposition of residual stress after PWHT and operating stress at normal speed and overspeed were discussed. The investigated results show that operating stress can be affected significantly by welding residual stress, and the distribution trend of superposition stress at the weld area is mainly determined by welding residual stress. The superposition of residual stress and operating stress is linear superposition, and the hoop stress distribution of superposition stress is similar with the distribution of residual stress. With the increasing overspeed, the distribution pattern of the hoop superimposed stress remains almost unchanged, while the stress level increases.

The Mariana Trench is the deepest location on earth and harbors unique microbial communities as evidenced by 16S rRNA gene amplicon and metagenomic sequencing. Obtaining culturable microorganisms from the Mariana Trench will contribute to a further understanding of hadal biogeochemical processes and act as a unique microbial reservoir with potential applications. Here, 825 bacterial strains, identified by 16S rRNA gene sequencing, were isolated from 12 water depths (0–10,400 m) of the Mariana Trench with 2216E and R2A media at 4 °C or 28 °C on four cruises during 2015–2017. These bacteria belong to four phyla, nine classes, 27 orders, 45 families and 108 genera. Alphaproteobacteria, Gammaproteobacteria, Actinobacteria_c, Bacilli and Flavobacteriia were the most abundant classes, accounting for 37.9%, 33.0%, 11.8%, 8.6% and 8.0% of the total bacterial isolates, respectively. 2216E and R2A media were found to have a better selectivity to Bacilli and Flavobacteriia, respectively. Fifty strains were potential novel bacterial species with a 16S rRNA gene similarity

Purpose. This study aimed to investigate the relationship of partial pressure of carbon dioxide (PaCO2) with BODE and GOLD in stable COPD subjects and to explore the predictive value of PaCO2 for severe COPD (BODE index score ≥5 or GOLD index score ≥3). Patients and Methods. In total, 80 participants with COPD and free from other conditions affecting PaCO2 were recruited. Arterial blood gases, BODE, GOLD, SGRQ, lung function, and other data were collected. The BODE index was calculated, and patients were divided into two groups according to the BODE index and PaCO2 median, respectively. We used Pearson’s correlation test and the receiver operating characteristic curves to evaluate the utility of PaCO2. Besides, the univariate and multivariate logistic regression analyses were conducted to verify whether PaCO2 was an independent factor associated with BODE grades. Results. COPD subjects with BODE ≥5 and GOLD ≥3 had significantly higher levels of PaCO2 ( p = 0.004, p = 0.001, respectively). In the high PaCO2 group, patients underwent poorer outcomes than the low PaCO2 group. PaCO2 was negatively correlated with forced expiratory volume in 1 second in percent of the predicted value (FEV1%) (r = −0.612, p p = 0.019). Conclusions. A higher level of PaCO2 was associated with a higher index for BODE or GOLD in COPD and had the predictive value for severe COPD.

Background We tend to find out whether BMI and weight have difference in the connection with the disease severity of AECOPD patients. Besides, we aim to explore the relationships between body fat (BF) and lean body mass (LBM) with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Methods Information like weight and body mass index (BMI) were recorded at hospital admission. BF and LBM were assessed using dual energy X-ray absorptiometry (DEXA). Logistic regression analysis, receiver operating characteristic (ROC) curves and other statistical analyses were performed. Results Weight and BF + LBM showed significant linkages with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) in multivariate logistic regression analysis (Model 3: OR = 0.932, p = 0.016; OR = 0.915, p = 0.006, respectively). And BMI did not show correlation with GOLD. In Stratification analysis, BF showed the predictive value for GOLD (AUC = 0.709, p = 0.004) while LBM showed the predictive ability for modified Medical Research Council scale (mMRC) (AUC = 0.761, p Conclusion BF + LBM and weight were better than BMI in the connection with the disease severity of AECOPD patients represtented by GOLD. BF and LBM may have different or even opposite effects on patients with AECOPD.

This study aimed to investigate the relationship of partial pressure of carbon dioxide (PaCOCOPD subjects with BODE ≥5 and GOLD ≥3 had significantly higher levels of PaCOA higher level of PaCO

Energetic compounds containing long nitrogen chain, have been a research hotspot. Fused heterocycles are stable due to their aromatic systems. The compound obtained by combining long nitrogen chain and fused ring can not only retain good energetic property, but also ensure better stability. This work designed eight fused heterocycle-based energetic compounds, 3H-tetrazolo[1,5-d]tetrazole (1) and its derivatives (2-8), containing a nitrogen chain with seven nitrogen atoms. The HOF, thermal stability, and energetic properties of these compounds were studied by using the DFT method. The results show that the introduction of -NO2, -N3, -NF2, -ONO2, -NHNO2 groups increased the density, HOF, detonation velocity, and detonation pressure greatly. The densities of 3, 5, 7, and 8 fall within the range designated for high-energy-density materials. The calculated detonation velocity of the compounds 3 and 8 are up to 9.86 km s-1 and 9.78 km s-1, which are superior to that of CL-20. The kinetic study of the thermal decomposition mechanism indicates that the N-R bonds maybe not the weakest bonds of these compounds. The tetrazole ring opening of the heterocycle-based energetic compounds, followed by N2 elimination is predicted to be the primary decomposition channel, whether or not they have substituent groups.

High-resolution observation of biological process is vital for biological researches and diagnosing diseases, which requires accurate diagnosis that involves coordinating imaging technologies such as fluorescence and magnetic resonance (MR). Nowadays, metal-based labels have been used for dual modality imaging. However, heavy metal ions are not environment-and organism-friendly. Therefore, it is a desirable to fabricate a metal-free label with fluorescence and MR properties. Herein, we synthesized boron–doped carbon dots (B–CDs) with dual modal properties through a one-pot solvothermal process. Compared with boron-free CDs, B–CDs exhibited apparent red-shift fluoresence emission, higher fluorescence intensity, and higher longitudinal relaxivity (r1 = 5.13 mM−1 s−1). It demonstrated that boron doping can enhance the fluorescence intensity of CDs, and maybe lead to form paramagnetic centers. The fluorescence and MR imaging of B–CDs make them a prospective label for clinical applications as a result of their oversimplified synthesis process, low cost, good biocompatibility and low toxicity. It will open a new window for building novel imaging labels.

Characterization of structural differences between coexisting conformational states of protein is difficult with conventional biophysical techniques. Hydrogen/deuterium exchange (HDX) coupled with top-down mass spectrometry (MS) allows different conformers to be deuterated to different extents and distinguished through gas-phase separation based on molecular weight distributions prior to determination of deuteration levels at local sites for each isolated conformer. However, application of this strategy to complex systems is hampered by the interference from conformers with only minor differences in overall deuteration levels. In this work, we performed differential HDX while the different conformers were separated according to their differing charge to size ratios in capillary electrophoresis. Mixtures of holo- and apo-myoglobin (Mb) and disulfide isomers of lysozyme (Lyz) were characterized in a conformer-specific fashion using this strategy, followed by conformation interrogation for the sequentially eluted

Nitrogen and sulfur co-doped graphene oxide nanosheets (N,S-GO) were prepared via a facile one-step solvent-free approach using citric acid as a precursor and cysteine as a dopant. First, the graphene nucleus was formed via intermolecular dehydration of citric acid; N and S were then incorporated into the graphene structure by attacking the margin of the graphene nucleus. Crosslinking among the graphene nucleus via intermolecular condensation led to the final N,S-GO. The latter exhibited favorable photoluminescence behaviors, such as a high fluorescent quantum yield of 56.0%, excellent photoluminescence stability within the pH range 5–12, and high tolerance to external ionic strength ≤1.0 mol L−1 NaCl. The fluorescence energy transfer between AgNPs and N,S-GO could induce efficient quenching of N,S-GO fluorescence, and the presence of biothiols in the system restored fluorescence effectively, so a fluorescence “off–on” procedure was developed for quantitative detection of biothiols. Under optimal conditions, the limit of detection for cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) was 11.8, 4.9, and 7.3 nmol L−1, respectively. This sensing platform exhibited good selectivity toward biothiols in the presence of other amino acids. The practicability of this sensing platform was well demonstrated by determining biothiol content in human plasma samples, which revealed spiking recoveries of 97.10–101.50% with Cys.

Traditional approaches to recycle and regenerate spent lithium-ion batteries by leaching are polluted and complicated. In this study, a green and simple technique has been provided to regenerate spent LiNi0.5Co0.2Mn0.3O2 cathode material, besides, the regenerated mechanisms are investigated. Studies indicate that lost lithium ions in material lattice are replenished by added lithium, meanwhile, insulting impurities on particle surface remove basically, cracked and broken particles disappear during the regeneration process. Electrochemical tests demonstrate that the performances of regenerated material improve significantly. The discharge capacities are 164.6 mAh g−1 at 0.1 C rate and 147 mAh g−1 at 1 C rate, respectively. They still could deliver a discharge capacity of 131 mAh g-1 with a high capacity retention rate of 89.12% after 100 cycles at 1 C, which can be considered as a preferable electrical energy storage system. The improved electrochemical performances prove a facial and effective regeneration process.

Energetic compounds containing long nitrogen chain, have been a research hotspot. Fused heterocycles are stable due to their aromatic systems. The compound obtained by combining long nitrogen chain and fused ring can not only retain good energetic property, but also ensure better stability. This work designed eight fused heterocycle-based energetic compounds, 3H-tetrazolo[1,5-d]tetrazole (1) and its derivatives (2-8), containing a nitrogen chain with seven nitrogen atoms. The HOF, thermal stability, and energetic properties of these compounds were studied by using the DFT method. The results show that the introduction of -NO2, -N3, -NF2, -ONO2, -NHNO2 groups increased the density, HOF, detonation velocity, and detonation pressure greatly. The densities of 3, 5, 7, and 8 fall within the range designated for high-energy-density materials. The calculated detonation velocity of the compounds 3 and 8 are up to 9.86 km s-1 and 9.78 km s-1, which are superior to that of CL-20. The kinetic study of the thermal decomposition mechanism indicates that the N-R bonds maybe not the weakest bonds of these compounds. The tetrazole ring opening of the heterocycle-based energetic compounds, followed by N2 elimination is predicted to be the primary decomposition channel, whether or not they have substituent groups.

The chloroplast-targeted ferredoxin-NADP + oxidoreductase (LFNR) is a hydrophilic flavin protein located at the end of the photosynthesis electron delivery chain in higher plants. It’s a hub for linking photosynthesis electronic transportation with chloroplast redox metabolism. In order to explore the relationship between LFNR gene and yellowing of ‘Huangjinya’controlled by light, we took separately one bud two leaves of ‘Huangjinya’ ‘Shuchazao’（CK） as the material to clone CsLFNR gene and then we obtained the sequence with a similarity of 100%, named CsLFNR1.1 (GenBank accession no. MT311318). Throw bioinformatics analysis, we know its cDNA gene length is 1095bp,coding 364 amino acids, The protein molecular weight is 40.623KDa, the theoretical isoelectric point is 8.86.CsLFNR1.1 is a alkaline protein without transmembrane structure and signal peptide, it has a chloroplast transport peptide(cTP), the secondary structure contains 23.35% alpha helix, 5.49% beta-corner, 28.85% extension chain and 42.31% irregular curling, It locates in the chloroplast. Through the Nucleotide BLAST, Protein BLAST and DNAMAN software, we found that C sLFNR1.1 and its translated amino acid sequences had 4 bases and 3 amino acid differences with NCBI ‘Shuchazao’ Gene CsLFNR1 (XM_028233617.1) and Protein (XP_028089418.1), the similarity reached 99.63% and 99.18%. CsLFNR1.1 and CsLFNR1 have small differences in the physical and chemical properties and secondary structure, the tertiary structure prediction template of them is consistent. In addition, they have the same conserved domain and active site. We took different shade ‘Huangjinya’ blades as the material for qRT-PCR, the result showed that the expression of CsLFNR1.1 gene response to the light intensity, its expression increased with the increase of light intensity. This study provides a theoretical basis and scientific basis for further exploring the role of CsLFNR1.1 gene in the light regulation process of the new shoots and leaves of ‘Huangjinya’.

In this study, we successfully developed a novel method to create [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) nanoscale aggregates using supercritical carbon dioxide (scCO2) annealing and fabricated bulk heterojunction (BHJ) solar cells with the nanoscale PCBM to improve device performance. PCBM forms nanoscale aggregates with a size of approximately 70 nm after scCO2 annealing at 11 MPa and 50 °C for 60 min. However, PCBM remains amorphous after thermal annealing (TA) at 150 °C for 5 min. The morphology, structure, and crystallinity of poly(3-hexylthiophene) (P3HT) in the scCO2-treated P3HT film are nearly the same as those in the TA-treated P3HT film. In the P3HT/PCBM blend, the formation of PCBM nanoscale aggregates by scCO2 treatment decreases the disturbance for P3HT crystallization and improves diffusion and regular packing of P3HT molecular chains. This increases the crystallinity of P3HT so that it becomes higher than that in the TA-treated blend film. The nanoscale aggregates of PCBM and the higher crystallinity of P3HT give the scCO2-treated P3HT/PCBM BHJ solar cells a maximum power conversion efficiency (PCE) of 2.74%, which is much higher than that of the as-cast device (PCE is 1.70%) and a little higher than the highest PCE (2.64%) of thermally annealed devices. These results indicate that scCO2 is an effective, mild, and environmental method to modulate the nanoscale aggregates of PCBM and to improve the PCE of BHJ solar cells. However, the size of the PCBM aggregates is a little larger than the most suitable size of the exciton diffusion length, leading to limited improvement of the PCE.

Elimination of harmful antibodies from organisms is a valuable approach for the intervention of antibody-associated diseases, such as Dengue hemorrhagic fever and autoimmune diseases. Since thousands of antibodies with different epitopes are circulating in blood, no universal method, except for the dual-functional conjugate of antigenic peptide and Fc-III mimetics (DCAF), was reported to target specific harmful antibodies. The development of DCAF molecules makes significant contribution to the progress of targeted therapy, which were demonstrated to eliminate the antibody dependent enhancement (ADE) effect in a Dengue virus (DENV) infection model and to boost the acetylcholine receptor activity in a myasthenia gravis model. Here, we describe a protocol for the synthesis of a DCAF molecule (DCAF1), which can selectively block 4G2 antibody to attenuate ADE effect during Dengue virus infection, and illustrate the binding of DCAF1 to 4G2 antibody by an ELISA assay. In our method, DCAF1 is synthesized by the conjugation of a hydrazine derivative of a Fc-III peptide and a recombinant expressed long α-helix with antigenic sequence through native chemical ligation (NCL). This protocol has been successfully applied to DCAF1 as well as other DCAF molecules for targeting their cognate antibodies.

A Gram-staining-negative, strictly aerobic, long-rod shaped with no flagellum and yellow-pigmented bacterium designated strain ZXX205T, was isolated from the hadal seawater at the depth of 7500 m in the Mariana Trench, Pacific Ocean. Phylogenetic analysis based on 16S rRNA gene sequences placed strain ZXX205T within the genus Winogradskyella and strain ZXX205T was most closely related to Winogradskyella flava KCTC 52348T and Winogradskyella echinorum KCTC 22026T with 96.9 % and 96.6 % sequence similarity, respectively. The sequence similarities to all other type strains were 96.3 % or less, and to the type strain Winogradskyella thalassocola LMG 22492T was 94.1 %. Growth occurred in the presence of 0–9.0 % (w/v) NaCl (optimum 3.0 %), at 4–45 °C (optimum 28 °C) and pH 6.0–9.0 (optimum pH 7.5). The sole respiratory quinone was menaquinone 6 (MK-6). The dominant cellular fatty acids (>10 %) of strain ZXX205T were iso-C15 : 0, iso-C15 : 1 G, iso-C16 : 0 3-OH and iso-C16 : 0. The polar lipids profile contained predominantly phosphatidylethanolamine, four glycolipids, four unidentified aminolipids and three unidentified lipids. The genomic DNA G+C content was 35.5 %. The DNA–DNA relatedness (DDH) values between strain ZXX205T and the most closely related species Winogradskyella flava and Winogradskyella echinorum were 21.1 and 20.4 %, respectively. Based on polyphasic taxonomic analysis, strain ZXX205T is considered to represent a novel species in the genus Winogradskyella of the family Flavobacteriaceae , for which the name Winogradskyella ouciana is proposed. The type strain is ZXX205T (=MCCC 1K03851T=JCM 33665T).

A coordination polymer (CP) based nanoprobe is described for colorimetric and fluorometric (dual mode) determination of ferric ion. The method is making use of a nanosized Gd(III)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin coordination polymer that was prepared by a single-step hydrothermal procedure. The nanoprobe is monodisperse and has uniform size and good water solubility. It also exhibits strong fluorescence and magnetic resonance response. On exposure to Fe(III), the color of the solution changes from red to brown as the concentration of Fe(III) exceed 5 μM. Similarly, the red fluorescence of the probe (with excitation/emission peaks at 420/675 nm) decreases as concentrations of Fe(III) increase from 0.5 to 100 μM. The limit of detection is 98 nM in the fluorometric mode. The assay was applied to the determination of Fe(III) in fetal bovine serum samples. Graphical abstract Schematic presentation of the synthesis and application of lanthanide-porphyrin based coordination polymer for ferric ion detection in colorimetric and fluorometric dual modes.

The synthesis and analysis of tetrazolo[1,5-b][1,2,4]triazine (1), 5,6,7,8-tetrahydrotetrazolo[1,5-b][1,2,4]triazine (2), 5,8-dinitro-5,6,7,8-tetrahydrotetrazolo[1,5-b][1,2,4]triazine (3), tetrazolo[1,5-b][1,2,4]triazin-7(8H)-one (4), 6,7-dimethyltetrazolo[1,5-b][1,2,4]triazine (5), and 6,7-dimethyl-5,6,7,8-tetrahydrotetrazolo[1,5-b][1,2,4]triazine (6) (intra-annular N5 chains) and the thermal decomposition mechanism of these compounds are described. These tetrazolo[1,5-b][1,2,4]triazines were characterized by 1H and 13C NMR, mass spectrometry, elemental analysis, and differential scanning calorimetry (DSC). Compounds 2, 4, 5, and 6 were further confirmed by single-crystal X-ray diffraction. Electrostatic potentials were estimated by density functional theory to establish the molecular electron distribution and their stabilities. Careful characterization indicated that these compounds containing N5 chains exhibited relatively high thermal stability. The study of the thermal decomposition mechanism indicates that the tetrazole ring opening of the fused aza-cyclic compounds, followed by N2 elimination is predicted to be the primary decomposition channel, whether or not they are conjugated systems, and whether or not they have substituent groups. The results could lay the groundwork for the development of new long catenated nitrogen atom chains in fused heterocycles. Keywords: Decomposition mechanism, Nitrogen chains, Stability, Fused heterocycles