[Otolith carbon and oxygen stable isotopes in laboratory-reared Schizothorax kozlovi]. / å››å·è£‚è ¹é±¼è€³çŸ³ç¢³ã€æ°§ç¨³å®šåŒä½ç´ ç‰¹å¾.

In order to investigate the role of otolith carbon (δ13C) and oxygen (δ18O) stable isotopes in identification of freshwater fish stocks, otolith δ13C and δ18O of cultured Schizothorax kozlovi at different ages were measured by stable isotope mass spectrometer. The relationships between otolith δ13C / δ18O and environment were discussed. The results showed that δ13C and δ18O values of S. kozlovi at age 1+ were not significantly correlated with otolith mass, but both were significantly different between lapillus and asteriscus. The average lapillus δ13C and δ18O values of S. kozlovi at different ages were (-9.58±0.06)‰ and (-8.33±0.17)‰, respectively. There was no significant difference of lapillus δ13C and δ18O between the sexes, but with significant difference among diffe-rent ages. The correlation of δ13C with δ18O was an effective method in identification of different culture stocks of S. kozlovi, which indicated the isotopic signatures of otolith could be used as a method to identify freshwater fish stocks.

Proprotein convertase subtilisin/kexin type 9 levels and aortic valve calcification: A prospective, cross sectional study.

OBJECTIVE: To investigate the possible association between plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) and the incidence and severity of calcific aortic valve disease (CAVD). METHODS: This prospective, cross sectional study involved patients with and without (controls) aortic valve calcification diagnosed by transthoracic echocardiography and dual source computed tomography (DSCT) scan. Aortic valves calcification scores were calculated from DSCT scans and patients were graded: grade 1, no calcification; grade 2, mildly calcified; grade 3, moderately calcified; grade 4, heavily calcified. Plasma PCSK9 levels were measured using an enzyme-linked immunosorbent assay. RESULTS: Forty patients were grade 1 (controls), 32 were grade 2, 48 were grade 3 and 32 were grade 4. Plasma levels of PCSK9 were significantly different between the four groups and the highest value was observed in the patients with grade 2 calcification. Only low-density lipoprotein cholesterol and lipoprotein (Lp)(a) were associated with the severity of CAVD. Regression analysis showed that age, Lp(a) and PCSK9 were independent predictors of CAVD. CONCLUSION: Data from this cross sectional study in a small sample of patients showed that plasma PCSK9 was correlated with the presence of CAVD but not its severity.

[Habitat suitability index model and minimum habitat area estimation of young Procypris rabaudi (Tchang): a simulation experiment in laboratory].

Under the conditions of simulated micro-habitat in laboratory, and by using experimental ecological methods, this paper evaluated the suitability index (HSI) of young Procypris rabaudi for habitat factors (substrate, light intensity and water depth). The habitat suitability models of the young P. rabaudi were established, and the minimum habitat area of the young P. rabaudi was estimated. The young P. rabaudi preferred the habitats with the gravel diameter from 10 to 15 cm, light intensity from 0.2 to 1.8 lx, and water depth from 0 to 15 cm (distance from the bottom of the tank). The three suitability index models of the substrate, light intensity and water depth for the young P. rabaudi were SI(s) = 1.7338e(-0.997x)(SI(S) is the suitability index of substrate, and x is the gravel diameter; R2 = 0.89, P < 0.01), SI(L) = 3.0121e(-1.339x)(SI(L) is the suitability index of light intensity, and x is the light intensity; R2 = 0.93, P < 0.01), and SI(W) = 2.4055e(-1.245x)(SI(W) is the suitability index of water depth, and x is the water depth; R2 = 0.97, P < 0.01), respectively. Arithmetic mean model HSI = (SI(S)+SI(L)+SI(W))/3 was most available for the estimation of the habitat suitability of young P. rabaudi. A total of seven groups of young P. rabaudi which established and maintained a relatively stable habitat area range were found. This habitat area ranged from 628 to 2015 cm2, with an average of 1114 cm2.

[TG-FTIR analysis of thermal degradation of bischofite's crystals with aniline hydrochloride].

The dehydration of bischofite is the key to the use of magnesium resource. Double salts or complex method is an important way to prepare anhydrous magnesium chloride. The crystals of bischofite and aniline hydrochloride were prepared through lowering the temperature of the mixture's aquatic solution slowly. The pyrolysis of aniline hydrochloride, bischofite and the crystals was qualitatively analyzed by TG-FTIR under 400 degrees C. We infered the reaction process through qualitative detection of escaping gas of each decomposition step. The Experimental results showed that there were three steps in the thermal decomposition of bischofite. In the first step, nearly four crystallized waters decomposed, while hydrolysis and decomposition took place together in the next two steps, but hydrolysis was the main reaction at the lower temperature (205-235 degrees C), and comparative decomposition was the main one at the higher temperature (235-287 degrees C). In the experimental temperature range, aniline hydrochloride didn't decompose. Water and aniline hydrochloride left the crystals at different temperature, and no hydrolysis reaction occurred. Anhydrous magnesium chloride can be prepared though this way.