Diversity of methanogens in the hindgut of grower and finisher pigs

This study examined the diversity of the methanogens in the hindgut of two different weight groups of pigs and correlated it with the amount of digested organic carbon (OC) and various components of dietary fiber. Five grower (58.9 ± 1.15 kg) and five finisher (89.4 ± 0.85 kg) Duroc × Landrace × Large Yorkshire female pigs were allocated into two groups and individually housed in cages. During the experiment, feed intake and fecal output were recorded for determination of apparent digestibility of OC, crude fiber (CF), neutral detergent fiber (NDF) and acid detergent fiber (ADF). At the end of the digestibility trial, pigs were sacrificed, and the contents of five segments of hindgut were sterilely collected to determine diversity of methanogens. Total microbial DNA of the hindgut contents was used as template for amplification of the methanogen16S rRNA gene, and the PCR products were further subjected to denaturing gradient gel electrophoresis (DGGE) analysis. Results show that the number of DGGE bands and Shannon diversity index for the 90 kg pigs were higher (P<0.05) than those for the 60 kg pigs. Methanogen communities did not alter along the different segments of the hindgut for the two weight groups. In addition, the amount of OC, CF, NDF and ADF digested (g/d) for the 90 kg pigs (1018.77, 23.11, 268.86 and 99.16, respectively) was higher (P<0.05) than the respective values for the 60 kg pigs (669.27, 13.77, 222.31 and 69.07), indicating that the higher diversity of  methanogens in the former group was related to the higher quantity of fiber materials fermented in the hindgut. The positive correlation (p<0.05) between number of DGGE bands and Shannon diversity index with quantity of digested OC and ADF further reaffirmed the above suggestion.Key words: Methanogen, pig, Shannon diversity index, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE)

Genetic analysis of farmed and wild stocks of large yellow croaker Larimichthys crocea by using microsatellite markers

The large yellow croaker (Pseudosciaena crocea) is one of the most economically important mariculture fish species in China. In this study, the genetic diversity and relationship among a wild stock, four farmed stocks and a selectively bred strain of large yellow croaker were assessed by 14 microsatellite markers. A total of 108 different alleles were detected over all loci. The average number of allele per locus ranged from 5.57 to 7.93, with an average of 6.75; the observed and expected heterozygosity ranged from 0.572 to 0.665 and from 0.649 to 0.751, with an average of 0.621 and 0.694, respectively; the Shannon’s diversity index ranged from 1.34 to 1.64, with an average of 1.48. The selectively bred strain had the lowest genetic diversity; all farmed stocks showed a slight reduction of genetic variability contrasted with wild stock. All stocks suffered severe bottleneck. The pair-wise FST, the phylogenetic tree, the factor correspondence analysis and the model based clustering analysis revealed that, the Ningbo stock, which was from Zhejiang province, was different from the remaining stocks from Fujian province. This study suggested that (1) the farmed stocks were at relatively low level of genetic diversity compared with the wild stock; (2) samples from Ningbo investigated in this study have a distinct divergence with those from Fujian province; (3) there had emerged significant differentiation among farmed stocks.Key words: Pseudosciaena crocea, large yellow croaker, genetic structure, microsatellite markers

In situ loading and delivery of short single- And double-stranded dna by supramolecular organic frameworks

Short DNA represents an important class of biomacromolecules that are widely applied in gene therapy, editing, and modulation. However, the development of simple and reliable methods for their intracellular delivery remains a challenge. Herein, we describe that seven water-soluble, homogeneous supramolecular organic frameworks (SOFs) with a well-defined pore size and high stability in water that can accomplish in situ inclusion of single-stranded (ss) and double-stranded (ds) DNA (21, 23, and 58 nt) and effective intracellular delivery (including two noncancerous and six cancerous cell lines). Fluorescence quenching experiments for single and double endlabeled ss- and ds-DNA support that the DNA sequences can be completely enveloped by the SOFs. Confocal laser scanning microscopy and flow cytometry reveal that five of the SOFs exhibit excellent delivery efficiencies that, in most of the studied cases, outperform the commercial standard Lipo2000, even at low SOF-nucleic acid ratios. In addition to high delivery efficiencies, the watersoluble, self-assembled SOF carriers have a variety of advantages, including convenient preparation, high stability, and in situ DNA inclusion, which are all critical for practical applications in nucleic acid delivery

Numerical simulation of mono-disperse droplet spray dryer under the influence of nozzle motion

With the increasing demand of uniform particles in the fields of medicine etc., the research on monodisperse droplet spray dryer (MDSD) becomes important. The drying efficiency of the current MDSD facility has to be improved to realize industrial applications. In this work, the influence of several kinds of nozzle movement on the drying process has been thoroughly explored by silico experiments. It is found that the velocity of the nozzle movement plays a key role in drying efficiency improvement. The movement of the nozzle leads to a wider distribution of the final moisture content of particles, and this effect becomes less significant with the increase of the velocity of nozzle motion. For all motion types under investigation, the circular motion is superior to the other motion types. It is revealed that the change of droplet dispersion state due to nozzle motion is the main factor that improves drying performance

A quantitative link between microplastic instability and macroscopic deformation behaviors in metallic glasses

Based on mechanical instability of individual shear transformation zones (STZs), a quantitative link between the microplastic instability and macroscopic deformation behavior of metallic glasses was proposed. Our analysis confirms that macroscopic metallic glasses comprise a statistical distribution of STZ embryos with distributed values of activation energy, and the microplastic instability of all the individual STZs dictates the macroscopic deformation behavior of amorphous solids. The statistical model presented in this paper can successfully reproduce the macroscopic stress-strain curves determined experimentally and readily be used to predict strain-rate effects on the macroscopic responses with the availability of the material parameters at a certain strain rate, which offer new insights into understanding the actual deformation mechanism in amorphous solids. © 2009 American Institute of Physics.published_or_final_versio

A quantitative link between microplastic instability and macroscopic deformation behaviors in metallic glasses

2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Scalable Synthesis of Uniform Mesoporous Aluminosilicate Microspheres with Controllable Size and Morphology and High Hydrothermal Stability for Efficient Acid Catalysis

Mesoporous aluminosilicates are promising solid acid catalysts. They are also excellent supports for transition metal catalysts for various catalytic applications. Synthesis of mesoporous aluminosilicates with controllable particle size, morphology, and structure, as well as adjustable acidity and high hydrothermal stability, is very desirable. In this work, we demonstrate the scalable synthesis of Al-SBA-15 microspheres with controllable physicochemical properties by using the microfluidic jet-spray-drying technology. The productivity is up to ∼30 g of dried particles per nozzle per hour. The Al-SBA-15 microspheres possess uniform controllable micron sizes (27.5-70.2 μm), variable surface morphologies, excellent hydrothermal stability (in pure steam at 800 °C), high surface areas (385-464 m2/g), ordered mesopore sizes (5.4-5.8 nm), and desirable acid properties. The dependence of various properties, including particle size, morphology, porosity, pore size, acidity, and hydrothermal stability, of the obtained Al-SBA-15 microspheres on experimental parameters including precursor composition (Si/Al ratio and solid content) and processing conditions (drying and calcination temperatures) is established. A unique morphology transition from smooth to wrinkled microsphere triggered by control of the Si/Al ratio and solid content is observed. The particle formation and morphology-evolution mechanism are discussed. The Al-SBA-15 microspheres exhibit high acid catalytic performance for aldol-condensation reaction between benzaldehyde and ethyl alcohol with a high benzaldehyde conversion (∼56.3%), a fast pseudo-first-order reaction rate (∼0.1344 h-1), and a high cyclic stability, superior to the commercial zeolite acid (H-ZSM-5). Several influencing factors on the catalytic performance of the obtained Al-SBA-15 microspheres are also studied

The association of chromosome 8p deletion and tumor metastasis in human hepatocellular carcinoma

Program no. 686postprin

Magnetic field effects on the electroluminescence of organic light emitting devices: A tool to indicate the carrier mobility

The magnetoelectroluminescence (MEL) of organic light emitting devices with a N, N′ -bis(l-naphthyl)- N, N′ -diphenyl- 1, l′ -biphentl- 4, 4′ -diamine:tris-(8-hydroxyquinoline) aluminum (NPB: Alq 3) mixed emission layer (EML) has been investigated. We find that MEL is maximized when the volume ratio of NPB of the mixed EML reaches 30% and the EML thickness is 40 nm. The features of MEL under various magnetic field strengths are insensitive to the change in EML thickness and mixing ratio. Meanwhile, MEL has a close relationship with the carrier mobility. We have conducted a theoretical study to further verify the relationship. Our experimental and theoretical results confirm that MEL can function as a tool to indicate the mobility. © 2010 American Institute of Physics.published_or_final_versio

Native donors and compensation in Fe-doped liquid encapsulated Czochralski InP

Undoped and Fe-doped liquid encapsulated Czochralski (LEC) InP has been studied by Hall effect, current-voltage (I-V), and infrared absorption (IR) spectroscopy. The results indicate that a native hydrogen vacancy complex donor defect exists in as-grown LEC InP. By studying the IR results, it is found that the concentration of this donor defect in Fe-doped InP is much higher than that in undoped InP. This result is consistent with the observation that a much higher concentration of Fe 2+ than the apparent net donor concentration is needed to achieve the semi-insulating (SI) property in InP. By studying the I-V and IR results of Fe-doped InP wafers sliced from different positions on an ingot, the high concentration of Fe 2+ is found to correlate with the existence of this hydrogen complex. The concentration of this donor defect is high in wafers from the top of an ingot. Correspondingly, a higher concentration of Fe 2+ can be detected in these wafers. These results reveal the influence of the complex defect on the compensation and uniformity of Fe-doped SI InP materials. © 2001 American Institute of Physics.published_or_final_versio