Carbon-doped boron nitride nanosheets as an efficient metal-free catalyst for the selective oxidation of H2S.

We report the first use of carbon-doped boron nitride (BCN) for H2S-selective catalytic oxidation. The obtained carbon-doped BN with an ultrathin layer structure exhibits outstanding H2S elimination and high S yield. In particular, BN doped carbon nanosheets display better catalytic performance than traditional catalysts, such as iron- and carbon-based catalysts. The findings of the present work shed a new light on metal-free catalysts for efficient catalytic removal of toxic H2S.

Estimation of appropriate dietary intake of iodine among lactating women in China based on iodine loss in breast milk.

OBJECTIVE: Data on iodine loss in breast milk, which are critical for establishing the appropriate dietary iodine intake for lactating women, is currently limited. A study was conducted to assess iodine loss in breast milk among Chinese lactating women to estimate the appropriate dietary intake of iodine. METHODS: A total of 54 pairs of healthy, lactating women and their infants aged 0-6 months were recruited from Tianjin and Luoyang cities in China. A 4 days infant weighing study was conducted to assess iodine loss in the breast milk of lactating women. Mothers were required to weigh and record their infants' body weights before and after each feeding for a 24 h period from 8:00 am to 8:00 am. During the weighing study, 2812 breast milk samples and 216 24-h urine samples were collected from each lactating mother for four consecutive days. In addition, a 3 days 24 h dietary record, including salt weighing and drinking water samples collecting, was performed by each lactating mother to determine dietary iodine intake during the weighing study. RESULTS: The average dietary iodine intake of lactating women was 323 ± 80 µg/d. The median breast milk iodine concentration and 24 h urinary iodine concentration of lactating women were 154 (122-181) and 135 (104-172) µg/L, respectively. The mean volume of breast milk and the mean iodine loss in the breast milk of lactating women were 711 ± 157 mL/d and 112 ± 47 µg/d, respectively. The appropriate dietary intake of iodine among lactating Chinese women is approximately 260 µg/d. CONCLUSIONS: Based on the iodine loss in breast milk (110 µg/d) found in this study, and the estimated average requirement of iodine for adults, the appropriate dietary intake of iodine among lactating Chinese women is 260 µg/d, which is higher than the 240 µg/d recommended by the China Nutrition Science Congress in 2013.

Influence of Crowdsourcing Innovation Community Reference on Creative Territory Behavior.

Crowdsourcing innovation community has become an important platform for enterprises to gather group wisdom. However, how the crowdsourcing innovation community plays a reference role in creative crowdsourcing participation is unclear. Based on the reference group theory, taking online impression management as the explanatory framework, this study explores the impact of crowdsourcing innovation community reference on the creative territory behavior, and the differences in the crowdsourcing innovation community reference effect among members of different community age groups. A total 524 valid two-stage questionnaires were collected. The empirical analysis results show that under the influence of informational reference and utilitarian reference of the crowdsourcing innovation community, community members are significantly more likely to adopt acquired impression management (AIM) than defensive impression management (DIM); under the influence of value expressive reference of the crowdsourcing innovation community, the possibility of adopting DIM behavior is significantly greater than that of adopting AIM behavior; compared with DIM behavior, AIM behavior has a more inhibitory effect on creative territory behavior. Interestingly, there are different community reference effects among members of different community age groups. In particular, the positive contribution of the elder members is not as good as that of the newcomers. The above research conclusions not only confirm the influence of crowdsourcing community reference on crowd participation decision making but also provide theoretical and practical enlightenment for exploring the cooperation mechanism of crowdsourcing innovation.

Efficiently Integrated Desulfurization from Natural Gas over Zn-ZIF-Derived Hierarchical Lamellar Carbon Frameworks.

Selective removal of carbonyl sulfide (COS) and hydrogen sulfide (H2S) is the key step for natural gas desulfurization due to the highly toxic and corrosive features of these gaseous sulfides, and efficient and stable desulfurizers are urgently needed in the industry. Herein, we report a class of nitrogen-functionalized, hierarchically lamellar carbon frameworks (N-HLCF-xs), which are obtained from the structural transformation of Zn zeolitic imidazolate frameworks via controllable carbonization. The N-HLCF-xs possess the desirable characteristics of large Brunauer-Emmett-Teller surface areas (645-923 m2/g), combined primary three-dimensional microporosity and secondary two-dimensional lamellar microstructure, and high density of nitrogen base sites with enhanced pyridine ratio (17.52 wt %, 59.91%). The anchored nitrogen base sites in N-HLCF-xs show improved accessibility, which boosts their interaction with acidic COS and H2S. As expected, N-HLCF-xs can be employed as multifunctional and efficient desulfurizers for selective removal of COS and H2S from natural gas. COS was first transformed into H2S via catalytic hydrolysis, and the produced H2S was then captured and separated and catalyzed oxidation into elemental sulfur. The above continuous processes can be achieved with solo N-HLCF-xs, giving extremely high efficiencies and reusability. Their integrated desulfurization performance was better than many desulfurizers used in the area, such as activated carbon, ß zeolite, MIL-101(Fe), K2CO3/γ-Al2O3, and FeOx/TiO2.

Sustainable synthesis of ordered mesoporous materials without additional solvents.

Micelles with well-defined nanostructures were generally formed in the presence of a suitable solvent. We report herein the accelerated construction of micelles with ordered nanostructures without assistance of additional solvents. The micelles were employed for ultrafast fabrication of ordered mesoporous silicas (OMS) using tetramethyl orthosilicate (TMOS) as silica source. When γ-aminopropyl triethoxysilane precursor was introduced, we obtained amine group (-NH2) decorated ordered mesoporous silicas (OMS-NH2-x, where x stands for the molar ratio of γ-aminopropyl triethoxysilane to TMOS). The resulted materials are large in BET surface area and tunable in content of -NH2 site, which are highly efficient for catalytic elimination of gaseous carbonyl sulfide and hydrogen sulfide. Using this strategy, other functionalized groups such as thiol and benzene can be also introduced into OMS. Furthermore, the introducing of phenolic precursor into the system leads to multiphase co-assembly for the formation of ordered mesoporous silica-polymer nanocomposites. It is demonstrated that the solvent-free ultrafast assembly offers a sustainable route for preparation of ordered mesoporous functional materials.

Highly Poison-Resistant Single-Atom Co-N4 Active Sites with Superior Operational Stability over 460 h for H2 S Catalytic Oxidation.

Efficient catalytic elimination of hydrogen sulfide (H2 S) with high activity and durability in nature gas and blast-furnace gas is very critical for both fundamental catalytic research and applied environmental chemistry. Herein, atomically dispersed Co atom catalysts with Co-N4 sites that can transform H2 S into S with conversion rate of ≈100% are designed and prepared. The representative 4Co-N/NC achieves a sulfur yield of nearly 100% and TOF(Co) of 869 h-1 at 180 °C. Importantly, remarkable long-term durability is achieved as well, with no obvious loss of catalytic activity in the run of 460 h, outperforming most of the reported catalysts. The short bond length and strong cooperation of Co-N are beneficial to improve the structural stability of the Co-N4 centers, and significantly enhanced resistance of water and sulfation over single-atom Co-catalyst. The present mechanism involves the stepwise hydrogen transfer process via the adsorbed *HOO and *HS intermediates.

Engineering of crystal phase over porous MnO2 with 3D morphology for highly efficient elimination of H2S.

In the present work, we report a facile oxalate-derived hydrothermal method to fabricate α-, ß- and δ-MnO2 catalysts with hierarchically porous structure and study the phase-dependent behavior for selective oxidation of H2S over MnO2 catalysts. It was disclosed that the oxygen vacancy, reducibility and acid property of MnO2 are essentially determined by the crystalline phase. Systematic experiments demonstrate that δ-MnO2 is superior in active oxygen species, activation energy and H2S adsorption capacity among the prepared catalysts. As a consequence, δ-MnO2 nanosphere with a hierarchically porous structure shows high activity and stability with almost 100% H2S conversion and sulfur selectivity at 210 °C, better than majority of reported Mn-based materials. Meanwhile, hierarchically porous structure of δ-MnO2 nanosphere alleviates the generation of by-product SO2 and sulfate, promoting the adoptability of Mn-based catalysts in industrial applications.

Design of Efficient, Hierarchical Porous Polymers Endowed with Tunable Structural Base Sites for Direct Catalytic Elimination of COS and H2S.

Hydrogen sulfide (H2S) is malodorous and highly toxic, and its selective removal from industrial feedstock is highly recommended for safety and environment protection. We report here a class of nitrogen-functionalized, hierarchical porous polymers (N-HPPs) synthesized from one-step alkylation-induced cross-linking without any involvement of templates. The as-engineered N-HPPs are large in BET surface area (792-1397 m2/g) and endowed with hierarchical porosity. The incorporated nitrogen species of N-HPPs act as structural base sites with properties that can be precisely controlled. By molecular simulation, the enhanced interactions between N-HPPs and H2S were verified. The synthesized N-HPPs show superb capacities for H2S adsorption (9.2 mmol/g at 0 °C, 1.0 bar) and display satisfactory IAST H2S/N2 and H2S/CH4 selectivity (88.3 and 119.6, respectively, at 0 °C). Catalyzed by the structural base sites located in the N-HPPs, the COS together with its derived H2S can be effectively eliminated under mild conditions.

Efficient low-temperature soot combustion by bimetallic Ag-Cu/SBA-15 catalysts.

In this study, the effects of copper (Cu) additive on the catalytic performance of Ag/SBA-15 in complete soot combustion were investigated. The soot combustion performance of bimetallic Ag-Cu/SBA-15 catalysts was higher than that of monometallic Ag and Cu catalysts. The optimum catalytic performance was acquired with the 5Ag1-Cu0.1/SBA-15 catalyst, on which the soot combustion starts at Tig=225°C with a T50=285°C. The temperature for 50% of soot combustion was lower than that of conventional Ag-based catalysts to more than 50°C (Aneggi et al., 2009). Physicochemical characterizations of the catalysts indicated that addition of Cu into Ag could form smaller bimetallic Ag-Cu nanolloy particles, downsizing the mean particle size from 3.7nm in monometallic catalyst to 2.6nm in bimetallic Ag-Cu catalyst. Further experiments revealed that Ag and Cu species elicited synergistic effects, subsequently increasing the content of surface active oxygen species. As a result, the structure modifications of Ag by the addition of Cu strongly intensified the catalytic performance.

Intercalation of nanostructured CeO2 in MgAl2O4 spinel illustrates the critical interaction between metal oxides and oxides.

Heterogeneous catalytic oxidation arises from the prerequisite oxygen activation and transfer ability of metal oxide catalysts. Thus, engineering intercalated nanounits and heterophase metal oxide structures, and forming interstitial catalyst supports at the nanoscale level can drastically alter the catalytic performances of metal oxides. This is particularly important for ceria-based nanomaterial catalysts, where the interactions of reducible ceria (CeO2) and nonreducible oxides are fundamental for the preparation of enhanced catalysts for oxygen-involved reactions. Herein, we intercalated nanostructured CeO2 in the bulk phase of magnesium aluminate spinel (MgAl2O4, referred to as MgAl), produced the interstitial effect between CeO2 nanoparticles and MgAl crystallites, thus boosting their oxygen transfer and activation capability. This nanoscaled intercalation engineering significantly enhanced the number and quality of tight contact points between the nanostructured CeO2 and MgAl units. Therefore, the oxygen storage/release capability (OSC) is exceptionally improved as revealed by various characterizations and catalytic carbon oxidation reaction. A mechanism similar to the Mars-van Krevelen process at the nanoscale level was invoked to explain the catalytic oxidation mechanisms. The reactive oxygen species of gaseous O2 originate formed the bulk of the as-obtained nanomaterial, where strong interactions between the CeO2 and MgAl components occured, which were subsequently released and diffused to the catalyst-interface at elevated temperatures. Silver supported on Ce-MgAl produced an approximately 4-fold higher concentration of active oxygen species than Ag/MgAl, and gives the optimum low-temperature oxidation at 229 °C. This study verifies the importance of the redox performance of ceria-spinel with enhanced OSC, which validates that the arrangement of contacts at the nanoscale can substantially boost the catalytic reactivity without varying the microscale structure and properties of spinel.

Polymeric carbon nitride nanomesh as an efficient and durable metal-free catalyst for oxidative desulfurization.

We report the first use of polymeric carbon nitride (CN) for the catalytic selective oxidation of H2S. The as-prepared CN with unique ultrathin "nanomeshes" structure exhibits excellent H2S conversion and high S selectivity. In particular, the CN nanomesh also displays better durability in the desulfurization reaction than traditional catalysts, such as carbon- and iron-based materials.

Effect of siRNA-silencing of SALL2 gene on growth, migration and invasion of human ovarian carcinoma A2780 cells.

BACKGROUND: The role of Spalt-like gene-2 (SALL2) in tumorigenesis remains incompletely elucidated. This study investigated the effects of SALL2 on human ovarian carcinoma (OC) A2780 cells and the probable mechanism. METHODS: Expression of SALL2 in human OC cell lines were detected by reverse transcription PCR (RT-PCR) and Western blot analysis. A2780 cells were transfected with small-interfering ribonucleic acid (siRNA) to silence SALL2. SALL2 expression was detected by RT-PCR, Western blot analysis and immunofluorescence assay. Cell proliferation was measured by CCK-8 assay and flow cytometry (FCM). Apoptosis was measured by FCM. Cell migration was detected by real-time cell analysis. Cell invasion was detected by transwell assay. mRNA expression of p21 was detected by quantitative real-time PCR. Western blot analysis was used to determine the expression of matrix metalloproteinase (MMP)2, MMP9, protein kinase B (PKB, also called Akt), and phosphorylated-Akt (p-Akt). RESULTS: SALL2 was expressed in six OC cell lines, and the expression was the highest in A2780 cells. Compared with that in the Scramble group, SALL2 expression in A2780 was downregulated after transfection with siRNA-2 and siRNA-3 for 48 h. Compared with that in the Scramble group, proliferation of A2780 cells in the siRNA-2 group increased after transfection for 24, 48 and 72 h. In the siRNA-2 group, the proportion of A2780 cells decreased in the G0/G1 phase, and cell apoptosis decreased after transfection for 48 h. Compared with that in the Scramble group, the cell migration and invasion abilities of A2780 cells increased. Compared with that in the Scramble group, p21 mRNA expression in A2780 cells decreased after transfection with siRNA2. When SALL2 was silenced, the expression of MMP2/9 and p-Akt in A2780 cells increased. Furthermore, the PI3K inhibitor LY294002 could effectively reversed SALL2 siRNA-induced phosphorylation of Akt, migration and invasion of A2780 cells. CONCLUSION: Transient silencing of SALL2 promotes cell proliferation, migration, and invasion, and inhibits apoptosis of A2780 cells. In SALL2 siRNA-silenced cells, p21 expression was decreased. SALL2 knockdown by siRNA induces the migration and invasion of A2780 cells; this phenomenon is possibly associated with the increased expression of MMP2/9 and the activation of the PI3K/Akt signalling pathway.

Increased CCL19 expression is associated with progression in cervical cancer.

Cervical cancer is the third most common cancer and the fourth leading cause of malignancy related mortality in women worldwide. CCL19 is highly expressed in human cancer cells, and ligand CCL19 binding to CCR7 induces actin polymerization and pseudopodia formation. However, whether or not CCL19 is involved in EMT of human cervical cancer needs further investigation. Using quantitative PCR and western blot analyses, we found that CCL19 is overexpressed in cervical cancer cell lines and tissues. Knockdown of CCL19 via siRNA inhibited the proliferation of cervical cancer cells by increasing apoptosis. Further analyses showed that inhibitory effects of CCL19 on cell migration and invasion were partly associated with EMT process. In conclusion, these data indicate that CCL19 is abnormally expressed in cervical cancer, indicating a novel and important role for CCL19 in cervical cancer malignant transformation.

Highly efficient CuxO/TiO2 catalysts: controllable dispersion and isolation of metal active species.

Porous Cu(x)O/TiO2 architectures with enhanced dispersion of the active phase are synthesized by a facile MOF-templated method. Such a unique composite would furnish excellent catalytic activity for CO oxidation under relatively mild conditions.

Clinical significance of leukocyte-associated immunoglobulin-like receptor-1 expression in human cervical cancer.

Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is broadly expressed on the majority of immune cells; however, the biological role of LAIR in solid tumors has yet to be elucidated. In the present study, using immunohistochemical staining analysis, the expression of LAIR-1 in human cervical cancer (HCC) and nontumor-adjacent tissue specimens was determined, and the results indicated that the expression of LAIR-1 in HCC tissue was higher compared with that in noncancerous tissue. The χ2 test was used to analyze the correlation between the expression of LAIR-1 in tumor tissues with clinicopathological parameters. The results showed that the expression of LAIR-1 in the cancer cell nucleus was significantly associated with tumor size, pathological differentiation, T classification and clinical stage. In addition, the expression in the cytoplasm was evidently associated with the number of positive lymph nodes. The HCC cell line, ME-180, which does not express LAIR-1, was stably transfected using LAIR-1 cDNA. Cell Counting Kit-8 and an annexin V assay showed that the overexpression of LAIR-1 in ME-180 cells suppressed the proliferation and anti-apoptosis capacity of the cells. These findings demonstrated that LAIR-1 is markedly overexpressed in HCC tissue, and that its expression status is associated with tumor progression. LAIR-1 may be a biomarker and target in the diagnosis and treatment of patients with HCC.

Leukocyte-associated immunoglobulin-like receptor-1 is expressed on human megakaryocytes and negatively regulates the maturation of primary megakaryocytic progenitors and cell line.

Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is an inhibitory collagen receptor which belongs to the immunoglobulin (Ig) superfamily. Although the inhibitory function of LAIR-1 has been extensively described in multiple leukocytes, its role in megakaryocyte (MK) has not been explored so far. Here, we show that LAIR-1 is expressed on human bone marrow CD34(+)CD41a(+) and CD41a(+)CD42b(+) cells. LAIR-1 is also detectable in a fraction of human cord blood CD34(+) cell-derived MK that has morphological characteristics of immature MK. In megakaryoblastic cell line Dami, the membrane protein expression of LAIR-1 is up-regulated significantly when cells are treated with phorbol ester phorbol 12-myristate 13-acetate (PMA). Furthermore, cross-linking of LAIR-1 in Dami cells with its natural ligand or anti-LAIR-1 antibody leads to the inhibition of cell proliferation and PMA-promoted differentiation when examined by the MK lineage-specific markers (CD41a and CD42b) and polyploidization. In addition, we also observed that cross-linking of LAIR-1 results in decreased MK generation from primary human CD34(+) cells cultured in a cytokines cocktail that contains TPO. These results suggest that LAIR-1 is a likely candidate for an early marker of MK differentiation, and provide initial evidence indicating that LAIR-1 serves as a negative regulator of megakaryocytopoiesis.

[Synthesis, spectral analysis and photocatalysis of Ag/K4Nb6,O17 heterojunction catalysts].

K4Nb6O17 photocatalyst was successfully synthesized by low-temperature hydrothermal method with layer structure. Considering that a large number of hydroxyl (Nb-OH) and oxygen species (Nb==O, Nb--O-) exist on the surface of K4Nb6O17 synthesized by hydrothermal method, Ag(en)2+ precursors were employed to synthesize Ag/K4Nb6O17 heterostructure photo-catalysts with highly dispersed Ag. Photocatalytic performance evaluation results show that the photodegradation rate of MO for K4Nb6O17 was remarkably improved when a small amont of Ag was loaded. The best loading dose of Ag is 0.5 at%. Based on various characterizations results of XRD, FTIR, UV-Vis DRS, XRF and TEM, the photocatalytic mechanism of Ag/ K4Nb6O17 heterostructure catalysts was illuminated in detail and the conclusions were drawn as follows: (1) K4Nb6O17 nanocrystals serve as electron and hole sources for degradation of an organic dye; (2) Ag nanoparticles on the surface of K4Nb6O17 nanocrystals act as a sink for the electrons, promote interfacial charge-transfer kinetics between the metal and semiconductor, improve the separation of photogenerated electron-hole pairs, and thus enhance the photocatalytic activity of Ag/K4Nb6O17 photocatalyst.

[Syntheses and spectral study of novel metal zinc organic phosphonate].

Two novel Zn2+ organic phosphonate Zn(4,4'-bipy)(HBCP) 1 and [Zn2 (phen)2 (BCP)(H2 BCP)].H2O2 were hydrothermally synthesized. The compound 1 is with two-dimensional layer framework whereas the compound 2 is zero-dimensional structure. The Zn2+ ion is four-coordinated in compound 1 while five or six-coordinated in compound 2. The relationship between their properties and structures was studied by using FTIR, two-dimensional (2D) correlation infrared spectroscopy under thermal perturbation, fluorescence and UV-Vis DRS spectrum etc. Upon light excitation at 350 nm, the compound 1 exhibits luminescence with a strong wide emission at 412 nm and a weak emission at 520 nm, while the compound 2 exhibits luminescence with a wide emission only at 398 nm under light excitation at 336 nm.

[2D correlation spectral study of a coordination polymer [Eu(PCPOA)3 (H2O)]n].

A novel two dimensional coordination polymer [Eu(PCPOA)3 (H2O)], was synthesized under hydrothermal condition. Based on the determination of the structure, the 2D correlation FTIR spectra with the perturbation of magnetism and the 2D correlation fluorescence spectra with the perturbation of temperature were investigated. The energy bonds were calculated using CASTEP Program of Material studio. The Europium ions are nine-coordinated and the ligands adopted two different modes to connect the Eu3+ ions to 2D layer structure. The study of the 2D-FTIR reveals that the carboxylates coordinate with the center ions not only as monodentate, but also as bidentate chelate. The 2D fluorescence spectra indicates that the transition of (5)D0-->(7)F2 is influenced intensively by the perturbation of temperature.

Synthesis and two-dimensional correlation infrared spectroscopy study of an organic-inorganic hybrid compound constructed by [Mo(5)P(2)O(23)] and Cu-imidazole components.

A novel compound, (Himi)(H(3)O) [Cu(imi)(2)](2)[P(2)Mo(5)O(23)].H(2)O 1 (imi=imidazole), was synthesized by hydrothermal method and characterized by X-ray single analysis, ESR spectrum, one-dimensional (1D) infrared spectroscopy and two-dimensional (2D) correlation infrared spectroscopy under thermal and magnetism perturbation. Crystal data for the compound 1: orthorhombic system, space group Pnma, a = 14.580(3)A, b = 21.073(4)A, c = 16.664(3)A, Z = 4. It consists of the Mo-Cu building-blocks [Cu(imi)(4)](2)[P(2)Mo(5)O(23)](2-), protonated imidazole cations and water molecules. In the Mo-Cu building-blocks, [Mo(5)P(2)O(23)](6-) clusters are linked by {Cu(imi)(4)}(2+) group to form a two-dimension parallelogram griddling structure. From the 2D IR correlation spectroscopy analyses, it is discovered that the intensity changes of Mo=O and P-O band are sensitive to the temperature variation, whereas the Mo-O bond linking to Cu(2+) can be remarkably affected by the magnetism variation. Furthermore, the intensity changes of P-O bands occur prior to that of the Mo=O band during the temperature elevation.