Selective Photochromic Response to Low-Dose X-ray Radiation Detection in One-Dimensional Cadmium-Viologen Complexes.

Photochromic viologen-based materials have emerged as one of the most promising candidates for the development of X-ray light detection applications, including medical diagnosis and treatment, environmental radiation inspection, and industrial crack detection. However, the design and construction of low-dose X-ray-sensitive complexes remains an immense challenge, especially for the in-depth dissection of their response mechanisms. Herein, by using N,N'-4,4'-bipyridiniodipropionate (CV) as functional sensitive structural units and cadmium as heavy atoms, two cadmium-viologen complexes with one-dimensional chained structures, namely, [Cd2Cl4(CV)(H2O)2]n (1) and [CdBr2(CV)]n (2), have been constructed, which exhibit a remarkable and selective photochromic response to low-dose X-ray radiation detection. Compound 1 is visually sensitive to both X-ray and UV light due to the more accessible photoinduced electron transfer (ET) pathways, while compound 2 only shows a slight color-changing process in response to UV light, in conformity with UV-vis absorbance analyses and kinetic studies. Surprisingly, compound 2 has longer ET pathways than 1, but not in response to high-energy X-ray light, seeming to contradict the previous phenomena. On further analysis, the key point in achieving X-ray-sensitive behavior should be a good balance among the electron donor-acceptor distance, intermolecular interaction, and X-ray absorbing capacity, as verified by density functional theory (DFT) and X-ray absorption strength calculations, X-ray photoelectron spectra, electron paramagnetic resonance measurements, and independent gradient model analysis. In particular, compound 1 is unprecedentedly sensitive to soft X-ray radiation, accompanied by an X-ray detection limit of as low as 2.91 Gy. These findings push forward the further development of low-dose X-ray sensing materials.

Sr2Pb(BeB5O10)(BO3): An Excellent Ultraviolet Nonlinear-Optical Beryllium Borate by the Pb-Modified Construction of a Conjugated System and Lone-Pair Effect.

The design of material by chemical and/or crystalline modification of a classic structure model benefits not only the optimized physical properties but also the controllability and efficiency. Herein, a new nonlinear-optical (NLO) beryllium borate crystal, Sr2Pb(BeB5O10)(BO3) (SPBBO), is successfully designed and synthesized by chemical and crystalline modification of the perovskite-like K3B6O10Cl NLO crystal. SPBBO displays a 3D BeB5O103- open-framework structure composed of interconnecting BeB5O13 groups with filled cationic Sr/Pb and anionic BO3 groups, which exhibits the striking enhancement of the second-harmonic-generation (SHG) response (8 × KDP) and birefringence (0.10) compared to the parent model. Replacement of K by Sr and Pb with a lone pair and replacement of Cl by conjugated BO3 result in the synergistic conjugation of Pb with host BeB5O103- and filled BO3 groups, contributing to the striking enhancement of the SHG and birefringence. Single-crystal measurements show that SPBBO has a short UV absorption edge of 280 nm with a wide energy band gap of 4.35 eV and an outstanding laser-induced resistant behavior with a remarkably high laser-induced damage threshold of 2100 MW cm-2. The excellent properties indicate that the SPBBO crystal is a very promising UV NLO functional material.

Enhanced Proton Conductivity by Aliovalent Substitution of Cadmium for Indium in Dimethylaminium-Templated Metal Anilicates.

Metal-organic frameworks (MOFs) with excellent proton conducting ability are crucial to fuel cells, chemical sensors, and redox flow batteries, but achieving them remain a challenge because of the difficulty in simultaneous fulfillment of large number of proton carriers, high mobility of protons, and long-term durable proton conduction. To explore a simple, efficient, and general route toward highly proton-conducting MOFs, we propose herein an aliovalent substitution metal strategy for isostructural aminium-templated MOFs which benefit the acquisition of rich proton sources without modifying ligands or exchanging protic organic molecules. This idea is verified by 100-fold enhancement of conductivity in compounds (Me2NH2)2[Cd(mdhbqdc)2] (Cd-BQ) and (Me2NH2) (Me2NH)[In(mdhbqdc)2] (In-BQ) (H2mdhbqdc = dimethyl 3,6-dihydroxy-2,5-benzoquinone-1,4-dicarboxylic acid) that feature three-dimensional diamond-like structures with two-dimensional intersected channels. Accompanied by the in situ formation of an anilicate ligand, a great number of -OH groups are grafted onto the inner wall of pores, which interact with neutral Me2NH and/or protonated Me2NH2+ cations via N-H···O hydrogen bonds. The high concentration of protons and dynamics of protic amines in the porous framework readily leads to a moderate conductivity of In-BQ (2.10 × 10-4 S cm-1, at 303 K under 95% RH) and an activation energy of 0.73 eV (95% RH). It should be noted that the aliovalent substitution of Cd(II) for In(III) results in the doubling of dimethylaminium proton carriers in Cd-BQ, indicating more frequent hopping and multiple proton-transfer pathways. This indication is supported by a very high protonic conductivity of 2.30 × 10-2 S cm-1 and a reduced activation energy of 0.48 eV under the same conditions. Molecular dynamics simulations visually elucidate the fact that compared with In-BQ, aliovalent-substituted Cd-BQ has shorter proton-migration distances, which in combination with more proton numbers results in more frequent hopping and sliding of protons, in agreement with the experimental results.

Indoor occurrence and health risk of formaldehyde, toluene, xylene and total volatile organic compounds derived from an extensive monitoring campaign in Harbin, a megacity of China.

Human exposure to formaldehyde, toluene, xylene (FTX) and other volatile organic compounds (VOCs) are associated with negative health impact. To characterize the exposure and health effects of FTX and TVOC from indoor environments, we conducted an extensive monitoring campaign involving 1278 measurements of 472 indoor locations in Harbin, a megacity in China from May 2013 to March 2018. The results showed that household had the highest mean formaldehyde concentration (0.171 ± 0.084 mg m-3) among all types of indoor environments. Meanwhile, there was no significant differences in formaldehyde concentration of the living room, master bedroom, secondary bedroom and study room (p > 0.05), as well as toluene and xylene. The highest mean concentration of toluene, xylene and TVOC was measured in public bath center. Great difference was found between formaldehyde concentrations in 2013 and other years, except 2015. There were great positive nonlinear correlations between the indoor temperature and concentration of formaldehyde (p < 0.01), good negative nonlinear correlations between the finish time of decoration and concentration of formaldehyde (p < 0.01), good positive linear correlations between the relative humidity and concentration of formaldehyde (p < 0.01). A risk assessment methodology was utilized to evaluate the potential adverse health effects of the individual FTX compounds according to their carcinogenicities. The predicted carcinogenic risk of formaldehyde was greater than the threshold value 1E-06 at all environments. The non-carcinogenic risk of TX compounds in the population is negligible. For estimating human health risk exposure, sensitivity analysis showed that more attention should be given to the influential variables such as the level of pollutants.

Modulator-Induced Zr-MOFs Diversification and Investigation of Their Properties in Gas Sorption and Fe3+ Ion Sensing.

In this paper, we synthesized three Zr-MOFs (Zr-SXU-1, Zr-SXU-2, and Zr-SXU-3) composed of identical ligands and metal clusters by using tetratopic carboxylic ligand PBPTTBA as the ligand and benzoic acids as modulators. These three Zr-MOFs showed different structures and topologies, and the connectivity of the Zr clusters varied from 8 in Zr-SXU-3, to 10 in Zr-SXU-1, and finally to 12 in Zr-SXU-2 due to the modulators used. Among them, Zr-SXU-1 represents an unusual 6-node network and [6(10)(11)7] transitivity. Besides, Zr-SXU-2 can only be obtained by using ditopic carboxylic acid as a second modulator when using benzoic acid as the main modulator, which is not reported in other Zr-MOFs synthesis. The adsorption and luminescence tests demonstrated their potential as gas reservoirs, separators, and sensors and also showed the importance of structure topologies to the applications.

Defect-enriched iron fluoride-oxide nanoporous thin films bifunctional catalyst for water splitting.

Developing cost-effective electrocatalysts operated in the same electrolyte for water splitting, including oxygen and hydrogen evolution reactions, is important for clean energy technology and devices. Defects in electrocatalysts strongly influence their chemical properties and electronic structures, and can dramatically improve electrocatalytic performance. However, the development of defect-activated electrocatalyst with an efficient and stable water electrolysis activity in alkaline medium remains a challenge, and the understanding of catalytic origin is still limited. Here, we highlight defect-enriched bifunctional eletrocatalyst, namely, three-dimensional iron fluoride-oxide nanoporous films, fabricated by anodization/fluorination process. The heterogeneous films with high electrical conductivity possess embedded disorder phases in crystalline lattices, and contain numerous scattered defects, including interphase boundaries, stacking faults, oxygen vacancies, and dislocations on the surfaces/interface. The heterocatalysts efficiently catalyze water splitting in basic electrolyte with remarkable stability. Experimental studies and first-principle calculations suggest that the surface/edge defects contribute significantly to their high performance.

An Investigation and Comparison of the Blending of LDPE and PP with Different Intrinsic Viscosities of PET.

The blending of aliphatic polyolefins and aromatic poly(ethylene terephthalate) (PET) based on different intrinsic viscosities (IV) was conducted in a torque rheometer. The comparison of blend components in terms of low density polythene (LDPE) and polypropylene (PP) in blending with PET was investigated, and the effects of the IV and proportion of PET on polymer blends are discussed in detail. Polymer blends with or without compatibilizer were examined by using a differential scanning calorimeter, thermogravimetric analyzer, rotary rheometer, field-emission scanning electron microscopy and a universal testing machine. It was found that the blending led to an increase in processability and a decrease in thermal stability for blends. The morphological analysis revealed that the incompatibility of blends was aggravated by a higher IV of PET, while this situation could be improved by the addition of compatibilizer. Results showed that there was an opposite effect for the tensile strength and the elongation at break of the polymer blend in the presence of a compatibilizer, wherein the influence of IV of PET was complicated.

Fourfold-Interpenetrated MOF [Ni(pybz)2] as Coating Material in Gas Chromatographic Capillary Column for Separation.

A fourfold interpenetrated diamond-like topological metal-organic framework (MOF), Ni(pybz)2 [pybz = 4-(4-pyridyl)benzoate] was successfully synthesized and fully characterized. This MOF can serve as coating material in gas chromatographic capillary column for the separation of some low boiling point essential oils. The prepared columns have good recognition ability and excellent selectivity toward a series of organic compounds, including alcohols, aldehydes, ketones, carboxylic acid, ethers, ester, and amines. It is found that the strained metal sites, van der Waals interactions, C-H···π attraction, and weak nonclassical hydrogen bond contribute to the recognition and selectivity of prepared columns. The grand canonical Monte Carlo technique is used to simulate the interactions of the adsorbates with MOF. The calculated van der Waals energies agree with the results of gas chromatographic separation.

Carbazolic Porous Framework with Tetrahedral Core for Gas Uptake and Tandem Detection of Iodide and Mercury.

A multifunctional carbazolic porous framework (Cz-TPM), with a tetrahedral core, has been synthesized by FeCl3 oxidative coupling polymerization. The Brunauer-Emmett-Teller surface area of the obtained polymers reaches 713.2 m2 g-1. Gas adsorption isotherms show that Cz-TPM exhibits large carbon dioxide (97.9 mg g-1, 9.8 wt %, 273 K, and 1 bar) and hydrogen uptake capacities (149.3 cm3 g-1, 1.34 wt %, 77 K, and 1 bar). Furthermore, Cz-TPM has been found to display tandem visual detection of iodide and mercury, respectively. The Cz-TPM dispersion turns to yellow in the presence of iodide salts and subsequently changes to nearly colorless on addition of Hg2+ salts that could be easily observed by the naked eye. Cz-TPM can detect I- via "turn off" fluorescence quenching, and then the in situ generated Cz-TPM@I complexes can recognize Hg2+ ions via "turn on" fluorescence recovery. More importantly, Cz-TPM is stable over common solvents and can be easily recovered by excessive water washing and centrifugation for further repeated use. As far as we know, carbazolic porous organic frameworks enabling detection of I- and Hg2+ have not been reported.

Elevated High Sensitivity C-Reactive Protein Increases the Risk of Microalbuminuria in Subjects With Cardiovascular Disease Risk Factors.

Microalbuminuria is an early biomarker of kidney injury, the aim of this study was to investigate the impact of high sensitivity C-reactive protein (hs-CRP) on microalbuminuria in adults with cardiovascular disease (CVD) risk factors. A total of 5667 subjects who voluntarily attended annual health screenings in the Third Xiangya Hospital of Central South University were included in the study. Logistic regression was used to determine the validity of hs-CRP to predict the presence of microalbuminuria. In the unadjusted regression analysis, male gender (OR 2.23), age (OR 1.71), smoking status (OR 1.48), obesity (OR 2.41), hypertension(OR 4.03), diabetes (OR 4.61), hyperuricemia (OR 1.83), and high hs-CRP(OR 1.61) were associated with microalbuminuria. Multivariate logistic regression analysis showed that the adjusted odds ratios (OR) of diabetes, hypertension, male, abdominal obesity, and high hs-CRP for microalbuminuria were 2.71, 2.57, 1.51, 1.28 and 1.41 in all subjects, respectively (P < 0.01). ROC analysis indicated that the cut-off for hs-CRP with better properties for screening of microalbuminuria was identified as ≥0.85 mg/L. The ORs of microalbuminuria were 1.97, 1.49, 1.32 and 1.71 times in male, abdominal obesity, diabetes and hypertension subjects with hs-CRP ≥ 0.85 mg/L, respectively, compared with those without elevated hs-CRP (P < 0.01). Elevated hs-CRP level was associated with microalbuminuria independent of cardiovascular risk factors. In addition, elevated hs-CRP increased the risk of developing microalbuminuria in subjects with CVD risk factors, indicating that chronic inflammation could amplify the deterioration of kidney by effect of CVD risk factors.

Diagnostic Accuracy of Serum Cystatin C for the Evaluation of Renal Dysfunction in Diabetic Patients: A Meta-Analysis.

This study aimed to evaluate the diagnostic value of serum cystatin C for renal dysfunction in diabetic patients. Eligible trials were searched from multiple databases, the data were extracted into a 2 × 2 table after the quality assessment of included articles. The pooled sensitivity, specificity and other parameters of accuracy of cystatin C were analyzed using Stata version 12.0. Seventeen studies involving 2173 patients were included. The pooled sensitivity and specificity of serum cystatin C for the diagnosis of renal dysfunction were 0.88 (95% CI: 0.83-0.91) and 0.87 (95% CI: 0.82-0.91), respectively. The positive likelihood ratio was 6.69 (95% CI: 4.83-9.26), negative likelihood ratio was 0.14 (95% CI: 0.10-0.20) and diagnostic odds ratio (DOR) was 46.57 (95% CI: 27.76-78.13). The area under the receiver operating characteristic curve was 0.94. Analysis of the 12 studies that investigated serum creatinine indicated that serum cystatin C was more accurate than serum creatinine for the diagnosis of renal dysfunction. Our results indicate that serum cystatin C is an effective index in diagnosing renal dysfunction comparing serum creatinine, serum cystatin C is more sensitivity for evaluation of renal function in diabetic patients.

[Near infrared spectroscopy study on water content in turbine oil].

Near infrared (NIR) spectroscopy combined with successive projections algorithm (SPA) was investigated for determination of water content in turbine oil. Through the 57 samples of different water content in turbine oil scanned applying near infrared (NIR) spectroscopy, with the water content in the turbine oil of 0-0.156%, different pretreatment methods such as the original spectra, first derivative spectra and differential polynomial least squares fitting algorithm Savitzky-Golay (SG), and successive projections algorithm (SPA) were applied for the extraction of effective wavelengths, the correlation coefficient (R) and root mean square error (RMSE) were used as the model evaluation indices, accordingly water content in turbine oil was investigated. The results indicated that the original spectra with different water content in turbine oil were pretreated by the performance of first derivative + SG pretreatments, then the selected effective wavelengths were used as the inputs of least square support vector machine (LS-SVM). A total of 16 variables selected by SPA were employed to construct the model of SPA and least square support vector machine (SPA-LS-SVM). There is 9 as The correlation coefficient was 0.975 9 and the root of mean square error of validation set was 2.655 8 x 10(-3) using the model, and it is feasible to determine the water content in oil using near infrared spectroscopy and SPA-LS-SVM, and an excellent prediction precision was obtained. This study supplied a new and alternative approach to the further application of near infrared spectroscopy in on-line monitoring of contamination such as water content in oil.

Apoptosis of murine melanoma B16-BL6 cells induced by quercetin targeting mitochondria, inhibiting expression of PKC-alpha and translocating PKC-delta.

PURPOSE: In our previous study, quercetin was found to induce apoptosis of murine melanoma B16-BL6 cells. The cellular and molecular mechanism of quercetin-induced apoptosis was investigated in the present study. METHODS: Nuclear morphology was determined by fluorescence microscopy. DNA fragmentation was analyzed by electrophoresis and quantified by the diphenylamine method. The transmembrane potential of mitochondria was measured by flow cytometry. Bcl-2, Bcl-X(L), PKC-alpha, PKC-beta, and PKC-delta were detected by Western blotting. Caspase activity was determined spectrophotometrically. RESULTS: Quercetin induced the condensation of nuclei of B16-BL6 cells in a dose-dependent pattern as visualized by Hoechst 33258 and propidium iodide dying. Phorbol 12-myristate 13-acetate (PMA), a PKC activator, significantly enhanced apoptosis induced by quercetin, while doxorubicin, a PKC inhibitor, markedly decreased it. Both PMA and doxorubicin showed a consistent effect on the fragmentation of nuclear DNA caused by various dosages of quercetin. Quercetin dose-dependently led to loss of the mitochondrial membrane potential, which was also significantly reinforced or antagonized by PMA and doxorubicin, respectively. Moreover, PMA showed reinforcement, while doxorubicin showed significant antagonization, of the quercetin-mediated decrease in the expression of Bcl-2. Quercetin promoted caspase-3 activity in a dose-dependent manner, which was also regulated by PMA and doxorubicin with a pattern similar to that seen in their effect on apoptosis, mitochondrial membrane potential and Bcl-2 expression, but none of these were directly affected by PMA and doxorubicin. Free fatty acid and chlorpromazine, a PKC activator and inhibitor, respectively, did not interfere with these effects of quercetin. B16-BL6 cells expressed PKC-alpha, PKC-beta, and PKC-delta. Quercetin dose-dependently inhibited the expression of PKC-alpha but not that of PKC-beta and PKC-delta. Doxorubicin almost completely blocked the effect of quercetin on the expression of PKC-alpha. Quercetin was also involved in the translocation of PKC-delta from the cytosol to the nucleus. PMA enhanced the effect of quercetin on the translocation of PKC-delta. CONCLUSIONS: These results indicate that quercetin induced apoptosis of murine melanoma B16-BL6 cells by injuring their mitochondria, increasing the activity of caspase-3, inhibiting the expression of Bcl-2 and PKC-alpha, and inducing the translocation of PKC-delta. Doxorubicin inhibited these effects of quercetin by blocking the decreased expression of PKC-alpha induced by quercetin while PMA increased these effects by enhancing the translocation of PKC-delta induced by quercetin.

In situ formation of meso-2,2'-oxydisuccinate via intermolecular dehydration coupling of D,L-malic acid: first coordination polymer of 2,2'-oxydisuccinate involving ether oxygen coordination: [Cd2(meso-odsc)(H2O)].

The first coordination polymer of 2,2'-oxydisuccinate, [Cd(2)(meso-odsc)(H(2)O)](odsc =meso-2,2'-oxydisuccinate), was hydrothermally synthesized from CdSO(4) and D,L-malic acid; X-ray crystallography shows that the D,L-malic acid was transformed in situ into meso-odsc via intermolecular dehydration coupling.

Quercetin inhibits the invasion of murine melanoma B16-BL6 cells by decreasing pro-MMP-9 via the PKC pathway.

PURPOSE: On the basis of the inhibitory effect of quercetin on the invasion of melanoma B16-BL6 cells previously reported by us, the mechanisms of quercetin-mediated inhibition of invasion were further investigated in the present study. METHODS: The ability of B16-BL6 cells to invade and migrate was evaluated in terms of the numbers of cells penetrating a reconstituted basement membrane in the Transwell coculture system. The relative levels and activities of matrix metalloproteinase-9 (MMP-9) and MMP-2 were determined by gelatin zymography and quantified using LabWorks 4.0 software. RESULTS: The quercetin-mediated inhibition of invasion was partially blocked by phorbol-12,13-dibutyrate (PDB), a PKC (protein kinase C) activator, and by doxorubicin, a PKC inhibitor. Only the proforms of MMP-9 (92 kDa) and MMP-2 (72 kDa) were detected by gelatin zymography. Quercetin dose-dependently decreased the gelatinolytic activity of pro-MMP-9. Doxorubicin also markedly reversed the quercetin-induced decrease. Quercetin showed a dose-dependent antagonism of increases in gelatinolytic activity of pro-MMP-9 induced by PDB and free fatty acid (another PKC activator). CONCLUSIONS: Together with the report that quercetin directly reduces PKC activity, the results reported here suggest that quercetin may inhibit the invasion of B16-BL6 cells by decreasing pro-MMP-9 via the PKC pathway.