Effect of thymol on microbial diversity in the porcine jejunum

Thirty two weaned pigs (24 d-old) were fed a diet without or with 1% (w/w) thymol. Pigs from each dietary treatment remained unchallenged or were challenged with Salmonella enterica serovar typhimurium. Jejunal content was collected and molecular microbial diversity was investigated using 16S rRNA gene polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Shannon index analysis showed no differences in diversity but Pearson coefficient analysis showed clear clustering of profiles, which delineated thymol fed and control groups irrespective of Salmonella challenge. Moreover, absence of bands corresponding to Actinobacillus minor (98-99% identity) was observed in thymol groups. A band corresponding to Citrobacter freundii (98% identity) was observed in almost all pigs from thymol groups, and only in 4 samples from pigs fed no thymol in the diet. Supplementation of pig diet with thymol caused clear changes in small intestine microbacterial community. Surprisingly, Salmonella infection caused no major perturbations to the community structure.     

Confinement and manipulation of individual molecules in attoliter volumes

We report observation of fluorescence from individual rhodamine 6G molecules in streams of charged 1-μm-diameter water droplets. With this approach, illumination volumes comparable to diffraction-limited fluorescence microscopy techniques (≤500 aL) are achieved, resulting in similarly high contrast between single-molecule fluorescence signals and nonfluorescent background. However, since the fluorescent molecules are confined to electrically charged droplets, in situ electrodynamic manipulation (e.g., focusing, switching, or merging) can be accomplished in a straightforward manner, allowing experimental control over both the delivery of molecules of interest to the observation region and the laser-molecule interaction time. As illustrated by photocount statistics that are independent of molecular diffusion and spatial characteristics of the excitation field, individual rhodamine 6G molecules in 1-μm droplets are reproducibly delivered to a target a few micrometers in diameter at a rate of between 10 and 100 Hz, with laser beam transit times more than 1 order of magnitude longer than diffusion-limited laser-molecule interaction times in equivalent volumes of free solution.     

Collection of fluorescence from single molecules in microspheres: effects of illumination geometry

The collection of fluorescence from a molecule inside a sphere illuminated with single or counterpropagating plane waves is modeled. The results are applicable to microdroplet-based single molecule detection techniques and to some microparticle characterization techniques using inelastic emission. The large position-dependent variations in the fluorescence collection rate are primarily attributable to variations in the excitation intensity. With plane-wave illumination the collection from shadow regions is low because the incident energy is refracted by the droplet surface away from these regions. The average collection rate from molecules in shadow regions can be increased by illuminating with counterpropagating beams.     

Effect of watershed parameters on mercury distribution in different environmental compartments in the Mobile Alabama River Basin, USA

Total mercury (THg) and mono-methylmercury (MeHg) levels in water, sediment, and largemouth bass (LMB) (Micropterus salmoides) were investigated at 52 sites draining contrasting land use/land cover and habitat types within the Mobile Alabama River Basin (MARB). Aqueous THg was positively associated with iron-rich suspended particles and highest in catchments impacted by agriculture. Sediment THg was positively associated with sediment organic mater and iron content, with the highest levels observed in smaller catchments influenced by wetlands, followed by those impacted by agriculture or mixed forest, agriculture, and wetlands. The lowest sediment THg levels were observed in main river channels, except for reaches impacted by coal mining. Sediment MeHg levels were a positive function of sediment THg and organic matter and aqueous nutrient levels. The highest levels occurred in agricultural catchments and those impacted by elevated sulfate levels associated with coal mining. Aqueous MeHg concentrations in main river channels were as high as those in smaller catchments impacted by agriculture or wetlands, suggesting these areas were sources to rivers. Elevated Hg levels in some LMB were observed across all types of land use and land cover, but factors such as shallow water depth, larger wetland catchment surface area, low aqueous potassium levels, and higher Chl a concentrations were associated with higher Hg burdens, particularly in the Coastal Plain province. It is suggested that the observed large variability in LMB Hg burdens is linked to fish displacement by anglers, differences in food web structure, and sediment biogeochemistry, with surficial sediment iron oxides buffering the flux of MeHg from sediments to deeper water pelagic food webs.     

厦门港龙现代广场

该项目是一个委托方案，功能上相当于“mail”，总建筑面积约10万平米。基址东临厦门市中山路，南靠霞溪路，西接思明东路，属于旧街区改造工程。设计上采取城市设计的手法，考虑到厦门城市原有的尺度，我们在沿街上沿用“骑楼”的形式。     

Incidence of adenoviruses in raw and treated water

Adenoviruses are of major public health importance and are associated with a variety of clinical manifestations, i.e. gastroenteritis, eye infections and respiratory infections. The importance of water in the epidemiology of adenoviruses and the potential health risks constituted by adenoviruses in water sources and supplies are widely recognised. This study was conducted to assess the incidence of human adenoviruses in raw and treated water systems. Various raw and treated water were routinely monitored for the presence of adenoviruses, over a 1-year period (July 2000-June 2001). The supplies were derived from acceptable quality surface water sources using treatment processes, which conform to international standards for the production of safe drinking water. Adenoviruses were detected by firstly amplifying the viruses in cell cultures and then amplifying the extracted nucleic acids of these viruses using molecular techniques (nested PCR). The results indicated human adenoviruses present in 13 (12.75%) of the raw and 9 (4.41%) of the treated water samples tested. The combination of cell culture and nested PCR has proved to be a quick and reliable method for the detection of adenoviruses in water environments.     

从读书行为到信息交流--南昌大学图文信息中心设计

本文回顾了南昌大学图文信息中心的设计过程。通过对项目背景、总图关系、功能空间形态、建筑形态等方面的介绍,探讨了当代高校图书馆的内涵和外延所发生的一些新的变化,指出了从读书行为到信息交流的转变是促使图书馆新形态产生的直接原动力。     

Assembly pathway analysis of DNA nanostructures and the construction of parallel motifs

We present a system for analyzing the assembly pathway of DNA nanostructures. This enables the identification, explanation, and avoidance of obstacles to proper structure formation. Potential problems include strand end-pinning and misfolding caused by the structural bias of nominally flexible junctions. We have used this system to guide the construction of parallel motifs that had previously, for unknown reasons, resisted assembly.     

Closed-loop, multiobjective optimization of two-dimensional gas chromatography/mass spectrometry for serum metabolomics

Metabolomics seeks to measure potentially all the metabolites in a biological sample, and consequently, we need to develop and optimize methods to increase significantly the number of metabolites we can detect. We extended the closed-loop (iterative, automated) optimization system that we had previously developed for one-dimensional GC-TOF-MS (O'Hagan, S.; Dunn, W. B.; Brown, M.; Knowles, J. D.; Kell, D. B. Anal. Chem. 2005, 77, 290-303) to comprehensive two-dimensional (GCxGC) chromatography. The heuristic approach used was a multiobjective version of the efficient global optimization algorithm. In just 300 automated runs, we improved the number of metabolites observable relative to those in 1D GC by some 3-fold. The optimized conditions allowed for the detection of over 4000 raw peaks, of which some 1800 were considered to be real metabolite peaks and not impurities or peaks with a signal/noise ratio of less than 5. A variety of computational methods served to explain the basis for the improvement. This closed-loop optimization strategy is a generic and powerful approach for the optimization of any analytical instrumentation.     

Canine cancer screening via ultraviolet absorbance and fluorescence spectroscopy of serum proteins

A cost-effective optical cancer screening and monitoring technique was demonstrated in a pilot study of canine serum samples and was patented for commercialization. Compared to conventional blood chemistry analysis methods, more accurate estimations of the concentrations of albumin, globulins, and hemoglobin in serum were obtained by fitting the near UV absorbance and photoluminescence spectra of diluted serum as a linear combination of component reference spectra. Tracking these serum proteins over the course of treatment helped to monitor patient immune response to carcinoma and therapy. For cancer screening, 70% of dogs with clinical presentation of cancer displayed suppressed serum hemoglobin levels (below 20 mg/dL) in combination with atypical serum protein compositions, that is, albumin levels outside of a safe range (from 4 to 8 g/dL) and globulin levels above or below a more normal range (from 1.7 to 3.7 g/dL). Of the dogs that met these criteria, only 20% were given a false positive label by this cancer screening test.