[Precipitable Water Vapor Retrieval with MODIS Near Infrared Data].

Precipitable water vapor (PWV) shows great significance in remote sensing quantitative application and ecological research. Aiming at solving the problems of traditional methods, an Improved Continuum Interpolated Band Ratio (ICIBR) algorithm was proposed based on the ratios of apparent reflectance of multi-channels in this paper. The ICIBR algorithm considers the absorption characteristics of water vapor absorption in three MODIS near infrared channels (Bands 17, 18 and 19) and the relationship between the PWV and the ICIBRs of above three channels were simulated by using the MORTRAN model. Then the PWV retrieval model for MODIS data was constructed. Texas, Oklahoma region, a typical arid/semi-arid areas, located in North South America were selected as the study area and four different MODIS 1B data were obtained to perform PWV retrieval experiments using the ICIBR algorithm. Last, the corresponding GPS PWV ground observation data provided by SuomiNet and the MODIS PWV product (MOD05) were obtained to verify the experiment results. Evaluation and comparison results showed that the PWV retrievals showed a higher consistency (r=0.967) with the GPS ground measured PWV data with smaller RMSE~0.276 cm and a total of 71.08% of observation points falling within PWV Expected Errors (EE~±0.05+0.15PWVgps). Moreover, the ICIBR algorithm showed an obviously great improvement in PWV estimation, which can effectively reduce 61% overestimation of PWV retrievals than MOD05 PWV products. This new algorithm is more simple and practical with an overall more reliable retrieval accuracy.

New pregnane and steroidal glycosides from Tribulus terrestris L.

Three new steroidal saponins were isolated from the fruits of Tribulus terrestris L. Their structures were elucidated by spectroscopic and chemical analysis as 16beta-(4'-methyl-5'-O-beta-D-glucopyranosyl-pentanoxy)-5alpha-pregn-3beta-ol-12,20-dione-3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranoside (1), 2alpha,3beta-dihydroxy-5alpha-pregn-16-en-20-one 3-O-beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranoside (2) and 26-O-beta-D-glucopyranosyl-(25R)-5alpha-furostan-20(22)-en-2alpha,3beta,26-triol-3-O-beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranoside (3).

The visualized polarity-sensitive magnetic nanoparticles.

Three polarity-sensitive organic molecules (DIAA, DIUA, and DISA) were designed and synthesized for functionalizing high-quality superparamagnetic Fe(3)O(4) nanoparticles (NPs) via the ligand exchange strategy to prepare polarity-sensitive Fe(3)O(4) NPs. The functional group is chosen to be the carboxyl group (one for DIAA and DIUA, two for DISA) that is a universal coordinating site for iron oxide NPs. The method for binding these functional molecules onto the surface of the NPs is simple and straightforward. Among the three molecules, the DISA molecules passivate the NPs' surface most efficiently owing to their particular structure with two carboxyl groups and a general good solubility. The DISA-functionalized Fe(3)O(4) NPs (DISA-Fe(3)O(4) NPs) display distinctly different fluorescence emissions in various solvents of different polarities with the magnetism well preserving. The prepared polarity-sensitive Fe(3)O(4) NPs that are dual functional can be used as a visualized polarity sensor and perform NPs' superparamagnetic properties simultaneously. It also provides a conceptual design for preparing the polarity-sensitive nanomaterials with multifunction.

Fluorescent conjugated polyfluorene with pendant lactopyranosyl ligands for studies of Ca(2+)-mediated carbohydrate-carbohydrate interaction.

A well-defined fluorescent conjugated polyfluorene with pendant lactopyranosyl ligands was easily prepared through Cu(I)-catalyzed azide/alkyne "click" ligation and Suzuki coupling polymerization. As a fluorescent multivalent model system of glycoconjugates, the polymer was first used for studies of metal ion-mediated carbohydrate-carbohydrate interaction based on fluorescence spectroscopy. A significant fluorescence quenching of the lactosyl-bearing polyfluorene was observed upon addition of calcium ion, which is attributed to the polymer aggregation derived from Ca(2+)-mediated complex formation. Dynamic light scattering can also prove Ca(2+)-induced aggregation of the polymer based on determination of the corresponding hydrodynamic diameters. The calcium-mediated lactose-lactose interaction was reversible when treated with EDTA. In control studies, Ca(2+)-induced fluorescence quenching can not be observed for cellobiosyl- or galactosyl-functionalized polymer analogues, which show that specific sugar structures are critical for carbohydrate-metal complex formation.

[Evaluation of diagnosis and prediction of degree of coronary stenosis by CAVI].

OBJECTIVE: To investigate the relationship between CAVI (Cardio-Ankle vascular Index) and the degree of coronary artery stenosis in elderly patients with type 2 diabetes, the predictive value of CAVI were evaluated using the degree of coronary artery stenosis. METHODS: Relevant clinical data including CAMI, BMI, blood pressure, smoking, age, Sbp, Dbp, history and blood biochemistry test were collected in 60 years or older patients with coronary artery stenosis diagnosed by coronary angiography, and the 298 cases were divided into two groups, A group (CAVI > or = 9), B group (CAVI < 9), to investigate the correlativity among the level of CAVI and cardiovascular risk factors; at the same time all cases were assigned to group C (diabetes group) and group D (non-diabetic group), to analyse the change of CAVI in coronary artery stenosis patients complicated with diabetes mellitus. RESULTS: A total of 298 eligible patients with coronary artery stenosis were enrolled, including 163 non diabetics and 135 type 2 diabetics. The analysis result shows that there was a positive correlation among CAVI, old age, BMI, LDL-C, multi-vessel lesion, diabetes. CONCLUSION: The increase of CAVI was most highly related to the coronary artery stenosis. The level of CAVI might be a helpful predictive indexes to the severity of coronary atherosclerosis.

Fluorescence-detecting cationic surfactants using luminescent CdTe quantum dots as probes.

A novel fluorescence quenching method for the determination of cationic surfactants (CS), specifically cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), and cetylpyridinium chloride (CPC), has been developed using water-soluble luminescent CdTe quantum dots (QDs) modified with thioglycolic acid (TGA). The possible interference from heavy and transition metals (HTM) has been efficiently eliminated through simple sample treatment with mercapto cotton made in-house. Under optimum conditions, the extent of fluorescence quenching of CdTe QDs is linearly proportional to the concentration of CS from 2.0 x 10(-7) to 7.0 x 10(-6) mol L(-1) with a detection limit of 5.0 x 10(-8) mol L(-1). The relative standard deviation for 1.0 x 10(-6) mol L(-1) CTAB is 2.5% (n = 6). The proposed method exhibits high sensitivity and selectivity and furthermore avoided the use of toxic organic solvents and tedious solvent extraction procedures. It has been applied to the determination of trace CS in natural river water and commodity samples with satisfactory results. Potential interference from heavy and transition metals is eliminated during photoluminescence detection of CS through simple sample pre-treatment with mercapto cotton.