The decoloration and mineralization of azo dye C.I. Acid Red 14 by sonochemical process: rate improvement via Fenton's reactions.

The degradation of azo dye C.I. Acid Red 14 (AR14) was investigated using cast iron in the absence and presence of low frequency ultrasound (59 kHz). The effects of pH, amount of cast iron ([Fe](0)) and initial concentration of AR14 ([dye](0)) on the degradation of AR14 by cast iron combined with low frequency ultrasound had been assessed. The degradation followed the first-order kinetics model. The first-order rate constant of AR14 degradation by cast iron was 7.50 x 10(-2) min(-1) while that by US-cast iron was 2.58 x 10(-1) min(-1). A 3.4-fold increase in the reaction rate was observed in the presence of ultrasound compared with that of absence of ultrasound. This kinetic effect is quantitatively accounted for a simple kinetic model based on the reaction of Fe(II) from cast iron in aqueous solution with sonochemically produced H(2)O(2) (Fenton's reaction). This latter effect illustrates a simple way of achieving a substantial improvement in the efficiency of sonochemical degradation reactions. It was found that for azo dye AR14, the rate of color decay was the first order with respect to the visible absorption of the dye. The destruction of the naphthalene rings in azo dyes was slower than that of color. A significant mineralization of AR14 was observed.

[Source and Distribution of Dissolved Metal Ions in the Backwater Area of Pengxi River in Three Gorges Reservoir].

This study uses the Gaoyang Lake section of the Pengxi River, the largest tributary on the northern bank of the Three Gorges Reservoir (TGR), as an example for exploring the distributions and dynamics of Ca, Zn, Fe, Cr, Pb, Cu, and Hg ions in the tributaries of TGR where the water level fluctuates due to dam regulation. Samples were taken 21 times, once every 17.3 days, at four sampling sites in Gaoyang Lake, which is in a perennial backwater zone of the Pengxi River, during one year from June 5, 2013 to May 29, 2014. At each sampling site, water samples were taken from the surface layer (0-0.5 m), middle layer, and bottom layer (0.5 m above the bed mud). During winter when the water was not stratified, the middle layer samples were taken at 1/2 depth, and when water was stratified in other seasons, the middle layer samples were taken from the thermal layer. Inductively coupled plasma atomic emission spectrometry (ICP-AES) and cold-vapor atomic absorption methods were adopted to determine the concentrations of the metals. Excel and SPSS were used for data analysis and Matlab for building 3-D prisms displaying concentration distributions of Hg ions in the high water level period (175 m, November-April in the ensuing year), sluicing period (May-middle June), low water level in the flooding season (145 m, June-August), and the storage period (September-November). The results provided the following observations ① Concentrations of Cr, Pb, Cu, Zn, and Hg ions were lower than those in Class Ⅲ of the water environment quality standard (GB 3838-2002). ② Cr, Pb, and Cu had high peak values during the storage and sluicing period, and the lowest values during the high water level period. Cr, Pb, and Cu were derived from the main stream of Yangtze, while Fe and Zn were from the Pengxi River locally. The concentration of Hg ions was affected by both the main stream and endogenous sources. As the water column stratified, metal ions did not mix among the stratified layers in Gaoyang Lake. ③ The conductivity was significantly lower during the high water level period than during other water level periods. The main material that affects the conductivity of Gaoyang Lake could be nonmetallic ions.

Endogenous endothelin-1 is required for cardiomyocyte survival in vivo.

BACKGROUND: Endothelin-1 (ET-1) has potent vasoconstrictor and hypertrophic actions. Pharmacological antagonists of endothelin receptors attenuate cardiac hypertrophy, have been approved for treatment of pulmonary hypertension, and are under investigation for treatment of heart failure. To investigate the role of ET-1 in the heart, we created mice with cardiomyocyte deletion of ET-1. METHODS AND RESULTS: Mice with cardiomyocyte-specific deletion of ET-1 are phenotypically normal when young. Remarkably, as the mice age or when young animals are subjected to aortic banding, they develop an unexpected phenotype of progressive systolic dysfunction and cardiac dilation. Echocardiography, necropsy, histology, and molecular phenotype confirm a dilated cardiomyopathy. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling analysis reveals greater abundance of apoptotic nuclei in the ET-1-deficient hearts. Transcriptional and Western analyses suggest enhanced tumor necrosis factor (TNF)-mediated apoptosis with increases in caspase-8 activity. These ET-1-deficient hearts also have diminished nuclear factor (NF)-kappaB activity, resulting in diminution of downstream inhibitors of TNF signaling. CONCLUSIONS: Local ET-1 gene expression is necessary to maintain normal cardiac function and cardiomyocyte survival in mice with both age and hemodynamic stress. This cardiac-protective effect is mediated by paracrine ET-1 modulation of TNF-related apoptosis, in part through upregulation of NF-kappaB signaling.

Transcriptional mapping and genomic analysis of the cardiac atria and ventricles.

The atria and ventricles of the heart have distinct development, structure, and physiology. However, only a few of the genes that underlie the differences between these tissues are known. We used a murine cardiac cDNA microarray to identify genes differentially expressed in the atria and ventricles. The reliability of these findings is supported by highly concordant repetition of hybridization, recognition of previously known atrial and ventricular isoforms of contractile proteins, and confirmation of results by quantitative PCR and in situ hybridization. We examined the most differentially regulated genes for evolutionarily conserved noncoding sequences and found that atrial-expressed genes have more predicted myocyte enhancer factor-2 (MEF2) binding sites than ventricle-predominant genes. We confirmed that messages for MEF2 family members are more abundant in the atria, as are their protein products. Moreover, the activity of a transgenic reporter construct for MEF2 activity is preferentially upregulated in the atria in response to hypertrophic stimuli. This study provides a greater understanding of the molecular differences between atria and ventricles and establishes the framework for an anatomically detailed evaluation of cardiac transcriptional regulation.

[Effects of marshland reclamation on evapotranspiration in the Sanjiang Plain].

Extensive reclamation of marshland into cropland has had tremendous effects on the ecological environment in the Sanjiang Plain. Observations over marshland, rice paddy and soybean field were made with eddy covariance measuring systems from May to October in 2005, 2006 and 2007. The objective of this study was to identify the effects of the conversion of marshland to cropland on evapotranspiration in the Sanjiang Plain. The results showed that the diurnal variation curves of latent heat flux were single peaked in marshland, rice paddy and soybean field. The daily maximum latent heat flux increased by 14%-130% in rice paddy in the three measuring years, however, in soybean field, it increased by 3%-77% in 2006 but decreased by 25%-40% in 2005 and 2007 by comparison with that in marshland. This difference was due to the change of leaf area index when marshland was reclaimed into cropland. Seasonal change of latent heat flux was identical for the three land use types. Daily averaged latent heat flux of rice paddy, from May to October, showed 38%-53% increase compared with that of marshland, which resulted from the increase in net radiation and leaf area index. When marshland was reclaimed into soybean field, the variation of daily averaged latent heat flux depended primarily on precipitation. Precipitation was the main factor that controlled evapotranspiration over soybean field which was usually in condition of soil water deficit. Drought caused 11%-17% decrease of daily averaged latent heat flux over soybean field in 2005 and 2007, while sufficient precipitation caused 22% increase in 2006, comparing to marshland. Similarly, during the growing season from June to September, total evapotranspiration of rice paddy increased by 24%-51% compared with that of marshland, and the total evapotranspiration of soybean field decreased by 19%-23% in 2005 and 2007 and increased by 19% in 2006. It is concluded that the evapotranspiration changes significantly when the marshland was reclaimed into rice paddy or soybean field in the Sanjiang Plain. Compared to marshland, the evapotranspiration is higher in rice paddy and soybean filed with sufficient precipitation, while lower in soybean field under drought. These changes are found to be highly related to the variations of net radiation, leaf area index and precipitation.

[Comparison of nocturnal ecosystem respiration measured with eddy covariance and chamber system at two agricultural sites in Sanjiang plain].

Measurements of nocturnal ecosystem respiration were conducted in a rice paddy of Sanjiang from July to September in 2004 and in a soybean field from June to September in 2005, using eddy covariance (EC) and dark chamber-gas chromatography (DC-GC). The differences of simultaneous data measured by two methods were not significant when night turbulent mixing was well. The correlations between two methods can be improved under more large friction velocity. EC measurements were poorly correlated to night ecosystem respiration estimated by chamber models for the variability inherent to EC measurements (R2 = 0.06, 0.23 for rice and soybean, respectively). However, this correlation can be improved by aggregating measurements over longer time period (R2 = 0.16, 0.75 for rice and soybean field, respectively). In general, whatever comparison with simultaneous chamber measurements or modeled results, eddy covariance measurements were consistently lower 4% - 30% than chambers, and this bias varied with crop growing stage, which were maximum in middle and minimum in early and late growing stage.

Mice with cardiomyocyte-specific disruption of the endothelin-1 gene are resistant to hyperthyroid cardiac hypertrophy.

Endothelin 1 (ET-1), a potent vasoconstrictor peptide expressed by endothelium, is also produced in the heart in response to a variety of stresses. It induces hypertrophy in cultured cardiac myocytes but only at concentrations far greater than those found in plasma. We tested whether ET-1 generated by cardiac myocytes in vivo is a local signal for cardiac hypertrophy. To avoid the perinatal lethality seen in systemic ET-1-null mice, we used the Cre/loxP system to generate mice with cardiac myocyte-specific disruption of the ET-1 gene. We used the alpha-myosin heavy chain promoter to drive expression of Cre and were able to obtain 75% reduction in ET-1 mRNA in cardiac myocytes isolated from these mice at baseline and after stimulation, in vivo, for 24 h with tri-iodothyronine (T3). Necropsy measurements of cardiac mass indexed for body weight showed a 57% reduction in cardiac hypertrophy in response to 16 days of exogenous T3 in mice homozygous for the disrupted ET-1 allele compared to siblings with an intact ET-1 gene. Moreover, in vivo MRI showed only a 3% increase in left ventricular mass indexed for body weight in mice with the disrupted allele after 3 weeks of T3 treatment versus a 27% increase in mice with an intact ET-1 gene. A reduced hypertrophic response was confirmed by planimetry of cardiac myocytes. We conclude that ET-1, produced locally by cardiac myocytes, and acting in a paracrine/autocrine manner, is an important signal for myocardial hypertrophy that facilitates the response to thyroid hormone.