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Characterization of Kiwifruit Xyloglucan

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j.urnal of Integrative Plant Biology 2009年第10期51卷 933-941页

作者： Xingj.n Li Naoki Sakurai Donald j. Nevins Academy of the State Administration of Grains Beijing 100037 China Graduate School of Biosphere Science Hiroshima University Kagamiyama 1-7-1 Higashi-hiroshima 739-8521 Japan Department of Plant Sciences University of California Davis CA 95616 USA

Structural characteristics of xyloglucan are constant in the pericarp cell walls of kiwifruit （Actinidia deliciosa） throughout fruit enlargement and maturation. Most of the xyioglucan （XG） persists in the cell walls of ripe kiwifruit. XG from the pericarp tissues of 36-h ethylene-treated kiwifruit was extracted as hemicellulose Ⅱ （HC-Ⅱ） with 4.28 M KOH containing 0.02% NaBH4, and purified using iodine precipitation and subsequent anion-exchange chromatography. This purifying protocol increased XG purity from 50 mol% in HC-Ⅱ fraction to 62 mol% in the purified XG powder. The molar ratio of glucose： xylose： galactose： fucose in the purified XG was 10： 6.9： 2.1： 0.3. Gel permeation chromatography indicated that purified XG had an average molecular-mass of 161 KDa, a value that exceeds the 95 KDa Mr determined for total polymeric sugars. Sugar linkage analysis confirmed the lack of fucose in the kiwifruit XG, but a small amount of arabinoxylan and low Mr glucomannan remained associated with this fraction.

关键词： Actinidia deliciosa cell walls glucomannan hemicellulose sugar linkage analysis xyloglucan

Purification of L-asparaginase II by crystallization

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Frontiers of Chemical Science and Engineering 2013年第1期7卷 37-42页

作者： Y. LIU M. PIETZSCH j. ULRICH Thermal Process Engineering Center for Engineering Science Martin Luther University Halle-Wittenberg D-06099 Halle (Saale) Germany Department of Downstream Processing Institute of Pharmacy Faculty of Natural Sciences I Martin Luther University Halle-Wittenberg D-06099 Halle (Saale) Germany

Here a case study ofL-asparaginase II out of a recombinant Escherichia coli is presented. The target protein was obtained by simple cell disintegration and acetone precipitation. The L-asparaginase II has been crystallized in three different forms in the following microbatch crystallization. The rod-shaped crystals （-400 μm edge length） were obtained at either 8℃ or 22℃ after 17h by addition of PEG6ooo. The rectangular-shaped crystals were obtained after further recrystallization of the rod-shaped crystals. The rhombic-shaped crystals formed at 8℃ after 12 days when cold ethanol was used instead of PEG6000. All crystallizations were performed in tris-acetate buffer （50mmol-L-1, pH 5.1）. By crystallization, the specific activity of L-asparaginase II has increased 5-fold. The protein content and the purity of the crystals were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）. The more concentrated L- asparaginase II out of an extract mixture and the presence of only less minor proteins after crystallization demonstrates that crystallization is an effective and mild method to purify the target protein. The single crystal X-ray diffraction pattern reveals that the crystals are proteins and the X-ray powder diffraction （XRPD） pattern shows clearly that the crystals forming in PEG600o and ethanol have different crystal structures.

关键词： protein crystallization L-asparaginase II purification

Acetaminophen and zinc phosphide for lethal management of invasive lizards Ctenosaura similis

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Current Zoology 2011年第5期57卷 625-629页

作者： Michael L. AVERY j.hn D. EISEMANN Kandy L. KEACHER Peter j. SAVARIE United States Department of Agriculture Wildlife Services National Wildlife Research Center Florida Field Station 2820 East University Avenue Gainesville FL 32641 USA United States Department of Agriculture Wildlife Services National Wildlife Research Center Ft. Collins CO 80225 USA

Reducing populations of invasive lizards through trapping and shooting is feasible in many cases but effective inte-grated management relies on a variety of tools, including toxicants. In Florida, using wild-caught non-native black spiny-tailed iguanas Ctenosaura similis, we screened acetaminophen and zinc phosphide to determine their suitability for effective population management of this prolific invasive species. Of the animals that received acetaminophen, none died except at the highest test dose, 240 mg per lizard, which is not practical for field use. Zinc phosphide produced 100% mortality at dose levels as little as 25 mg per lizard, equivalent to about 0.5% in bait which is lower than currently used in commercial baits for commensal rodent con-trol. We conclude that zinc phosphide has potential as a useful tool for reducing populations of invasive lizards such as the black spiny-tailed iguana provided target-selective delivery methods are developed [Current Zoology 57 （5）： 625~529, 2011].

关键词： Acetaminophen Black spiny-tailed iguana Ctenosaura similis Florida Invasive Zinc phosphide

INFLUENCE OF INTERNAL HYDROGEN ON THE HYDROGENEMBRITTLEMENT OF AUSTENITIC STAINLESS STEEL

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Acta Metallurgica Sinica(English Letters) 1997年第3期10卷 228-232页

作者： Y Tan D.H Zhouand j. Feng (Institute of Structural Mechanics, Chengdu 610003, China) Inst of Structural Mechanics Chengdu China

The HE (hydrogen embrittlement) behavior of two kinds of austenitic stee Cr21Ni6Mn9 and 1Cr18Ni9Ti is reprted in this paper. The factors (temperc-ture/strain rate/stress concentration coefficient and purity of hydrogen) are restricted to the severe conditions under which HE is easy to occur. The concentmtion of in-ternal hydrogen in samples is changed by varying the time during which samples are placed in 24 MPa hydrogen at 473 K Then the tensile properties of the samples are tested. The results indicate that the degree of the hydrogen-induced plastic loss (L)of Cr21Ni6Mn9 is different with the internal hydrogen(CH). Howeven even when CH is as high as 70 PPm L is 15% and the fracture may be explained as a larpe amount of internal hydrogen hinders the cross-slip of dislocations when the steel is *** the metastable steel 1Cr18Ni9Ti the hydrogen-induced plastic loss is severer than that of Cr21Ni6Mn9. When CH is 40 PPm its L is as high as 42%. The mechanism may be explained as a larpe amount of hyderpen decreases the stacking fault enerpy and brittle ε-phase is produed in the high CH areas.

关键词： austenitic stainless steel internal hydrogen hydrogen embrittlement hydrogen-induced ductility loss

Efficient Extraction of Agarose from Red Algae Using Ionic Liquids

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Green and Sustainable Chemistry 2014年第4期4卷 190-201页

作者： Tushar j. Trivedi Arvind Kumar AcSIR CSIR—Central Salt and Marine Chemicals Research Institute G. B. Marg Bhavnagar India Salt and Marine Chemicals Division CSIR—Central Salt and Marine Chemicals Research Institute G. B. Marg Bhavnagar India

We explored the possibility of using ionic liquids (ILs) as medium for efficient extraction of agarose via dissolution of red algae under varying conditions of heating or microwave irradiation. As compared to conventional methods, a very high extraction yield of good quality agarose (as high as 39 wt%) could be achieved depending upon the nature of used IL and applied experimental conditions. purity of extracted agarose was confirmed from various spectral and analytical techniques, such as 1H and 13C NMR, FTIR, circular dichroism (CD), gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The physicochemical properties, such as gelling or melting temperature, viscosity and gel strength of extracted agarose hydrogels have been measured and compared with the agarose obtained from similar source reported in the literature. ILs were recovered after the extraction of agarose and were reused for further extraction experiments. % Recycling and extraction ability of recycled ILs in different cycles have been measured. The developed extraction process of utilizing ILs as medium is easy, simple and highly efficient as compared to the conventional methods of agarose extraction from algae.

关键词： Red Algae Ionic Liquids Agarose Thermal or Microwave Heating Recycling Extraction Ability

A Review of Metallic Fractal Aggregates

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Open j.urnal of Metal 2011年第2期1卷 17-24页

作者： Rodolfo j. Slobodrian Claude Rioux Michel Piché 不详

Metals are the main components of the Earth’s mass and are characterized by high thermal and electrical conductivity as well as high reflectivity of electromagnetic fields. Finely divided metals are efficient catalysers and this indicates the relevance of surfaces when their ratio to volume becomes large. This is a characteristic of fractal aggregates and their constituent monomers (spheroidal or other) in the micrometer to nanometer scales. Exotic fern shaped aggregates are also produced. All aggregates exhibit large ratios of surface to volume. Condensation of metallic vapours allows to obtain particle sizes much smaller than those obtained via grinding techniques and far superior in purity. Exotic alloys of non miscible metals have been obtained at the micrometer scale. Thermal and laser evaporation methods of metals followed by condensation are described. Low gravity aggregation experiments were also carried out on aircraft in parabolic flight.

关键词： Fractals Monomers Aggregates Metals Alloys

Rapid Validated Stability Indicating Method for Nizatidine and Its Impurities Quantification

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American j.urnal of Analytical Chemistry 2011年第3期2卷 314-323页

作者： Antony Raj.Gomes Pannala Raghuram j. Sriramulu Nimmakalaya Srinivas 不详

This research article describes stability indicating fast liquid chromatographic method for determination of chromatographic purity and assay of Nizatidine as a alternate for two different methods for chromatographic purity and assay as given in USP Monograph and *** Monograph. Proposed method is developed on Waters symmetry RP18 (50 × 4.6 mm), 3.5 μm stationary phase using gradient elution with combination of Ammonium acetate Diethyl amine buffer, Methanol and Tetrahydrofuran as mobile phase. Favorable results are obtained under developed conditions, which guarantee good separation of studied components. Whereas, data obtained from method validation confirm specificity, high sensitivity, linearity in a range of studied concentrations, repeatability and good accuracy of this method. Considerable degradation observed in oxidation stress condition was detected by this method. Eight impurities are studied among which impurity-5 is found maj.r degradant. The stress samples are assayed against a qualified standard and the mass balance is found close to 99.2%. The developed method can be used for routine samples as well as stability studies.

关键词： Column Liquid Chromatography Nizatidine Forced Degradation Validation Stability Indicating

Activity of the Enzyme Gamma-Glutamyl Transferase (GGT) as a Prognostic Tool for Heart Failures

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Advances in Bioscience and Biotechnology 2017年第9期8卷 324-341页

作者： Susan j. Ali Ayoub A. Bazzaz Abdulwadood I. Arif Department of Chemistry Faculty of Education University of Tikrit Tikrit Iraq Department of Basic Sciences Faculty of Dentistry University of Kerkuk Kerkuk Iraq

Heart failure (HF) incidence could cause further complications to other body organs, which might sometimes be fatal, and is accompanied by various biochemical alterations i.e. enzymatic changes. The obj.ctive of this study was to measure the activity of gamma glutamyl transferase (GGT) as an early diagnostic indicator for HF patients;and to isolate the iso-enzymes for the purpose of finding the Michaelis-Menten constant (Km) and the maximum velocity Vmax of each iso-enzymes which enable follow up the development of HF disease. Samples of blood sera were collected from 120 patients of both genders (70 males and 50 female, aged 30 - 38 years old). Partial purification of iso-enzyme GGT was performed by precipitation, gel filtration, and ion exchange of the two iso-enzyme (I and II). The purity of the enzyme was confirmed by using Sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) into two clear bands. The results were compared with other 80 samples of healthy volunteers whose ages ranged between 25 - 78 years old, used as control. There has been a significant increase (p ≤ 0.01) in the activity of the enzyme GGT in the heart failure patient (66.9 ± 1.7 IU/L) in comparison with control (12.07 ± 0.60 IU/L). It is concluded that measurements of the iso-enzyme GGT could well benefit as a clear indicator criteria in prognosis of heart failure.

关键词： Purification GGT-Enzyme Heart Failure Gel-Electrophoresis Iso-Enzymes-I

Measurement of the Energy Spectrum of a 6 MV Linear Accelerator Using Compton Scattering Spectroscopy and Monte Carlo-Generated Corrections

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International j.urnal of Medical Physics, Clinical Engineering and Radiation Oncology 2020年第4期9卷 186-200页

作者： Sameer Tanej. Laura j. Bartol Wesley Culberson Larry A. De Werd School of Medicine and Public Health University of Wisconsin-Madison Madison USA

Purpose: The energy spectrum of a linear accelerator used for dose calculations is determined during beam commissioning by iteratively adj.sting the spectrum and comparing calculated and measured percent depth-dose curves. Direct measurement of the energy spectrum using pulse mode detectors is particularly challenging because of the high-energy, high fluence nature of these beams and limitations of the detector systems. This work implements a Compton scattering (CS) spectroscopy setup and presents detector corrections and spectral unfolding techniques to measure the spectrum of a 6 MV linear accelerator using a pulse mode detector. Methods: Spectral measurements were performed using a Varian Clinac 21EX linear accelerator and a high-purity germanium (HPGe) detector. To reduce fluence to the detector, a custom-built lead shield and a CS spectrometry setup were used. The detector was placed at CS angles of 46°, 89°, and 125°. At each of these locations, a detector response function was generated to account for photon interactions within the experimental geometry. Gold’s deconvolution algorithm was used to unfold the energy spectrum. The measured spectra were compared to simulated spectra, which were obtained using an experimentally benchmarked model of the Clinac 21EX in MCNP6. Results: Measurements were acquired and detector response corrections were calculated for all three CS angles. A comparison of spectra for all CS angles showed good agreement with one another. The spectra for all three angles were averaged and showed good agreement with the MCNP6 simulated spectrum, with all points above 400 keV falling w

关键词： Linear Accelerator Energy Spectrum Spectrometry High purity Germanium Detectors Monte Carlo