Hyperglycemia-induced oxidative stress and fibrosis play a crucial role in the development of diabetic cardiomyopathy (DCM). Tetrahydrocurcumin (THC), a major bioactive metabolite of natural antioxidant curcumin, is reported to exert even more effective antioxidative and superior antifibrotic properties as well as anti-inflammatory and antidiabetic abilities. This study was designed to investigate the potential protective effects of THC on experimental DCM and its underlying mechanisms, pointing to the role of high glucose-induced oxidative stress and interrelated fibrosis. In STZ-induced diabetic mice, oral administration of THC (120 mg/kg/d) for 12 weeks significantly improved the cardiac function and ameliorated myocardial fibrosis and cardiac hypertrophy, accompanied by reduced reactive oxygen species (ROS) generation. Mechanically, THC administration remarkably increased the expression of the SIRT1 signaling pathway both in vitro and in vivo, further evidenced by decreased downstream molecule Ac-SOD2 and enhanced deacetylated production SOD2, which finally strengthened antioxidative stress capacity proven by repaired activities of SOD and GSH-Px and reduced MDA production. Additionally, THC treatment accomplished its antifibrotic effect by depressing the ROS-induced TGFβ1/Smad3 signaling pathway followed by reduced expression of cardiac fibrotic markers α-SMA, collagen I, and collagen III. Collectively, these finds demonstrated the therapeutic potential of THC treatment to alleviate DCM mainly by attenuating hyperglycemia-induced oxidative stress and fibrosis via activating the SIRT1 pathway.

A novel preconcentration method is presented for the determination of Mo isotope ratios by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) in geological samples. The method is based on the separation of Mo by extraction chromatography using N-benzoyl-N-phenylhydroxylamine (BPHA) supported on a microporous acrylic ester polymeric resin (Amberlite CG-71). By optimising the procedure, Mo could be simply and effectively separated from virtually all matrix elements with a single pass through a small volume of BPHA resin (0.5 ml). This technique for separation and enrichment of Mo is characterised by high selectivity, column efficiency and recovery (~100%), and low total procedural blank (~0.18 ng). A 100 Mo-97 Mo double spike was mixed with samples before digestion and column separation, which enabled natural mass-dependent isotopic fractionation to be determined with a measurement reproducibility of < 0.09‰ (d 98/95 Mo, 2s) by MC-ICP-MS. The mean d 98/95 Mo SRM 3134 (NIST SRM 3134 Mo reference material; Lot No. 891307) composition of the IAPSO seawater reference material measured in this study was 2.00 ± 0.03‰ (2s, n = 3), which is consistent with previously published values. The described procedure facilitated efficient and rapid Mo isotopic determination in various types of geological samples. Une nouvelle m ethode de pr e-concentration est pr esent ee pour la d etermination des rapports isotopiques du Mo par spectrom etrie de masse a source plasma et multi-collection (MC -ICP-MS) dans des echantillons g eologiques. La m ethode est bas ee sur la s eparation du Mo par Chromatographie d'extraction en utilisant du Nbenzoyle-N-ph enylhydroxylamine (BPHA) support e par une r esine polym ere d'ester acrylique microporeuse (Amberlite CG-71). En optimisant la proc edure, le Mo peutêtre simplement et efficacement s epar e de la quasitotalit e des el ements de la matrice avec un seul passage a travers un petit volume de r esine BPHA (0,5 ml). Cette technique de s eparation et d'enrichissement du Mo est caract eris ee par une grande s electivit e, une grande efficacit e et une grande r ecup eration de la colonne (~100%), et un faible total de la proc edure de blanc (~0,18 ng). Un double spike Mo 100 -Mo 97 a et e m elang e avec les echantillons avant la digestion et la s eparation sur colonne, ce qui a permis la d etermination du fractionnement isotopique naturel d ependant de la masse avec une reproductibilit e de mesure de < 0,09 ‰ ( d98/95 Mo, 2s) par MC -ICP-MS. La composition moyenne d 98/95 Mo SRM3134 (mat eriau de r ef erence NIST SRM 3134 Mo; Lot n°891307) de l'eau de mer de r ef erence IAPSO mesur ee dans cette etude est de 2,00 ± 0,03 ‰ (2s, n = 3), ce qui est coh erent avec les valeurs pr ec edemment publi ees. La proc edure d ecrite facilite une d etermination efficace et rapide des rapports isotopiques du Mo dans divers types d' echantillons g eologiques.Mots-clés : isotopes du molybd ene, N-benzoyle-Nph enylhydroxylamine, chromatographie d'extraction, pr econcentration, double spike, MC-...

HighlightsLead bioaccessibility in the gastric phase (GP) and Pb-RBA was generally lower in mining soils (0.4629%and 7.026%) than smelting (1992% and 3184%) and farming soils (1399% and 5161%), with more Pb in the residual fraction in mining soils. Lead bioaccessibilityvaried with assays, with SBRC (3.099%)producing significantly higher bioaccessible Pbthan other assays (0.4684%) in the gastric phase. However, Pb bioaccessibilityin the intestinal phase (IP) of all assays sharply decreased to 0.01-20%possibly due to Pbsorption to solid phase at higher pH. Lead bioaccessibility by UBM-GPassay was best correlated with Pb-RBA (r 2 =0.67), followed by IVG-GP (r 2 =0.55).Among different Pb fractions, strong correlation was found between Pb bioaccessibility/Pb-RBA andthe sum of exchangeable and carbonate fractions. Our study suggested thatUBM-GP assay has potential to determine Pbbioaccessibility in contaminated soils in China.

We report an improved procedure for the determination of the platinum-group elements (PGE) and Re, and Os isotopes from a single sample aliquot by isotope dilution (ID) using inductively coupled plasma-mass spectrometry (ICP-MS) and negative thermal ionisation mass spectrometry (N-TIMS), respectively. A two-stage column method was used to purify PGE-Re from their sample matrix and interfering elements (e.g., Mo, Zr and Hf) after Os had been separated by CCl 4 solvent extraction. The first column separation step used cation exchange resin (AG50W-X8) to concentrate PGE-Re and some potential interfering elements (e.g., Mo, Zr and Hf). In the second step, N-benzoyl-N-phenylhydroxylamine (BPHA) extraction resin was used to separate PGE-Re from the remaining interfering elements, which all remained strongly absorbed to the resin. The method was used to determine the PGE and rhenium, and Os isotope ratios in a range of geochemical reference materials (TDB-1, WGB-1, BHVO-2 and UB-N). The obtained results agree well with those previously published. This new method enables PGE-Re abundances and Os isotopic ratios to be determined on the same sample digestion, and circumvents the problems created by sample heterogeneity when comparing PGE and Re-Os isotope data.

In this study, Re and Os isotopes were systematically determined in six geological reference materials (RMs; covering a wide range of lithologies) using the Carius tube (CT) digestion technique with and without hydrofluoric acid desilicification. Our results show that the HF desilicification increased the Re extraction efficiency (by 9-15%) evidenced from basaltic and andesitic rocks (e.g., BHVO-2, TDB-1 and AGV-2). This implies that a small proportion of Re resides in silicate phases. For mafic-ultramafic rocks (e.g., BCR-2, WGB-1 and WPR-1), Re extraction efficiencies obtained by the CT digestion with and without HF desilicification were similar. This may indicate that Re in these rocks may dominantly reside in some phases (e.g., magnetite and sulfides) that could be completely dissolved in aqua regia solutions without the aid of HF desilicification. Our results also show that the HF desilicification increased Os extraction efficiency (by 13-99%) in some RMs (e.g., BHVO-2, WGB-1 and AGV-2). This observation suggests that a portion of Os-rich trace phases may occur as inclusions in the silicate phases that act as isolators at~200 mesh sizes. This study demonstrates that the HF desilicification step prior to CT digestion is important for complete extraction of Re and Os in geological samples.

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a b s t r a c tThe purpose of this work is to improve the precision of the elemental analysis of coal using laserinduced breakdown spectroscopy (LIBS). The LIBS technique has the ability to allow simultaneous elemental analysis and on-line determination, so it could be used in the elemental analysis of coal. Organic components such as C, H, O, N and inorganic components such as Ca, Mg, Fe, Al, Si, Ti, Na, and K of coal have been identified. The precision of the LIBS technique depends strongly on the experimental conditions, and the choice of experimental parameters should be aimed at optimizing the repeatability of the measurements. The dependences of the relative standard deviation (RSD) of the LIBS measurements on the experimental parameters including the sample preparation parameters, lensto-sample distance, sample operation mode, and ambient gas have been investigated. The results indicate that the precision of LIBS measurements for the coal sample can be improved by using the optimum experimental parameters.