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Unexpected Kirkendall effect in twinned icosahedral nanocrystals driven by strain gradient

Nano Research 2020年第10期13卷 2641-2649页

作者： Jingbo Huang Yucong Yan Xiao Li Xurong Qiao Xingqiao Wu Junjie Li rong shen Deren Yang Hui Zhang State Key Laboratory of Silicon Materials School of Materials Science&EngineeringCyrus Tang Center for Sensor Materials and ApplicationsZhejiang UniversityHangzhou 310027China Advanced Technology Department SAIC Motor Corporation LimitedShanghai 201804China State Key Laboratory of Heary Oil Proessing School of Materials Science and EngineeringChina University of PetroleumQingdao 266580China

Nanoscale Kirkendall effect has been widely used for rationally fabricating high-quality hollow nanocrystals, but often requires the intrinsic diffusion coefficient of out-diffusion materials higher than that of in-diffusion components. Here we demonstrate an unexpected Kirkendall effect that occurs in diffusing intrinsically faster Cu atoms into Pd icosahedra, leading to the formation of PdCu alloyed hollow nanocrystals. The control experiment with Pd octahedra replacing icosahedra indicates the critical role of twin boundaries in facilitating such unexpected Kirkendall effect. In addition, geometric phase analysis and density functional theory calculation show that out-diffusion of Pd atoms in the icosahedra is faster than in-diffusion of Cu atoms, particularly through the twin boundaries, upon the strain gradient with an inward distribution from tensile to compressive strains. The unexpected Kirkendall effect is also found in the interdiffusion of Ag and Pd atoms in Pd icosahedra. Our finds break the limitation of the intrinsic diffusion coefficient for the synthesis of hollow nanocrystals through Kirkendall effect and are expected to enormously enrich the family of hollow nanocrystals which have shown great potential in broad areas, such as fine chemical production, energy storage and conversion, and environmental protection. This work also provides a deep understanding in the diffusion behavior of atoms upon the strain gradient.

关键词： Kirkendall effect diffusion coefficient interdiffusion chemical potential icosahedral nanocrystals strain gradient

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Production of conjugated linoleic acids by Lactobacillus plantarum strains isolated from naturally fermented Chinese pickles

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第11期12卷 923-930页

作者： Pei LIU sheng-rong shen Hui RUAN Qian ZHOU Liu-liu MA Guo-qing HE School of Biosystems Engineering and Food Science Zhejiang University Hangzhou 310058 China College of Food Science and Engineering Shandong Agricultural University Tai ＇an 271018 China

Naturally fermented pickles harbour many lactic acid bacteria （LAB）. Forty-three LAB strains with conjugated linoleic acid （CLA）-producing ability were isolated from three naturally fermented pickle brines. Of these isolates, Ip15 identified as Lactobacillus plantarum by API 50 CHL system and full-length 16S rDNA sequence analysis exhibited the highest CLA-producing ability （26.1% conversion） at 48 h in de Man Rogosa Sharpe （MRS） broth in the presence of 100 IJg/ml of linoleic acid （LA）. Compared to other strains, L. plantarum strain Ip15 showed the highest tolerance upon increased levels of LA in the medium, i.e., up to 600 μg/ml. This strain converted about 25% of LA into CLA isomers [predominantly cis-9, trans-11 CLA （9-CLA） and trans-lO, cis-12 CLA （10-CLA）], of which 75% was 9-CLA. Interestingly, though the conversion rate of LA into CLA by Ip15 remained stable between 100 to 600μg/ml LA levels in the medium, it dropped sharply at 1000 μg/ml. Taken together, the Ip15 strain displayed relatively high LA tolerance with higher conversion rate, which implies that this strain is a valuable candidate for enhancing the CLA content in food-sources like pickles.

关键词： Conjugated linoleic acids Lactobacillus plantarum Lactic acid bacteria Pickle Gas chromatography

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Tomato Growth and Organic Acid Changes in Response to Partial Replacement of NO_3^--N by NH_4^+-N

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Pedosphere 2004年第2期14卷 159-164页

作者： DONGCai-Xia shenQi-rong WANGGe CollegeofResourcesandEnvironmentalSciences NanjingAgriculturalUniversityNanjing210095（China）／E-mail：cxdong@***

A hydroponic experiment was conducted to study the effect of partial replacement of NO-3-N by NH4+-N on the seedling growth and organic acid content of tomato (Lycopersicon esculentum Mill.). A completely randomized design was established with three replications and five treatments, i.e., NO-3-N/NH4+-N of 100/0, 75/25, 50/50, 25/75 and 0/100. Results showed that 25% replacement of NO3--N by NH4+-N significantly (P = 0.05) improved fresh and dry weight, revealing that a proper percentage of NH4+-N was important for tomato nitrogen nutrition. This could increase the plant growth even though tomato was a crop that preferred nitrate nutrition. Also an increase in the proportion of NH4+-N in the nutrient solution led to a significant decrease (P = 0.05) in malate, citrate and fumarate. However, the 25% NH4+-N plus 75% NO3--N treatment had no significant effect (P = 0.05) on the 2-ketoglutarate, succinate or oxalic acid content, showing that only some organic acids in tomato plants were affected. Only pyruvate increased significantly (P = 0.05), and it only increased for 25% and 50% replacement of NO3--N by NH4+-N. Metabolism of these organic acids, especially malate, citrate and fumarate, should be further studied at the molecular level in vegetables applied with different nitrogen forms.

关键词： NH_4^+-N nitrogen forms NO_3^--N organic acid tomato (Lycopersiconesculentum Mill.)

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Nitrification Potential of Soils Under Liquid Incubation Conditions

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Pedosphere 2005年第3期15卷 379-385页

作者： YUANFei RANWei shenQi-rong CollegeofResourcesandEnvironmentalSciences NanjingAgriculturalUniversityNanjing210095（China）

A red soil, a fluvo-aquic soil and a permeable paddy soil were used in a long-term investigation to study changes in nitrification with treatments: 1) soil incubation, 2) liquid incubation inoculated with soil samples, and 3) liquid incubation inoculated with ammonia-oxidizing bacteria (AOB) from the soils. There were significant differences (P < 0.001) in nitrification rates among the three soils when measured for 28 days by adding (NH4)SO4 at the rate of 154 mg N kg-1 dry soil to fresh soil. However, t…

关键词： ammonia-oxidizing bacteria nitrification pH soil type

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UNSTEADY INTERMITTENT FLOW IN A ROTATING CURVED PIPE

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Journal of Hydrodynamics 2004年第2期16卷 158-165页

作者： YINJian-an shenXin-rong CHENHua-jun ZHANGBen-zhao DepartmentofMechanics ZhejiangUniversityHangzhou310027Chinae-mail：mec-zbzq@emb***

The effects of rotation and intermittent frequency on the flow transition ofsecondary flow and, main flow were examined in detail. Certain hitherto unknown flow patterns werefound. A numerical study was performed to study the characteristics of unsteady intermittent flow ina rotating curved pipe. Due to the rotation, both the Coriolis force and the centrifugal forcecould contribute to the unsteady intermittent flow and some complicated phenomena can be found. Theresults indicate that the unsteady intermittent flow are mainly characterized by five parameters:the Dean number Dn, the curvature κ, the maximal force ratio F (of the Coriolis force to thecentrifugal force in a cycle), the intermittent frequency parameter η (the ratio of a pulslatingtime to the cycle period), and the Womersley number α. Present works shows the natures of theunsteady intermittent flow in a rotating curved pipe.

关键词： unsteady flow secondary flow rotating pipes

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New Insights into the Nitrogen Form Effect on Photosynthesis and Photorespiration

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Pedosphere 2007年第5期17卷 601-610页

作者： GUO Shi-Wei ZHOU Yi GAO Ying-Xu LI Yong shen Qi-rong College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 （China）

Under high light conditions, ammonium nutrition has a negative effect on plant growth. This suggests that the adverse effects of ammonium nutrition on plant growth may be related to carbon gain, photosynthesis, and photorespiration. However, there is no consistent evidence of a specific mechanism that could explain the plant growth reduction under ammonium supply. It is generally accepted that during the light reaction, a surplus of nicotinamide adenine dinucleotide hydrogen phosphate （NADPH） is produced, which is not completely used during the assimilation of CO2, Nitrate reduc- tion in the leaf represents an additional sink for NADPH that is not available to ammonium-grown plants. Nitrate and ammonium nutrition may use different pathways for NADPH consumption, which leads to differences in photosynthesis and photorespiration. The morphological （i.e., cell size, mesophyll thickness, and chloroplast volume） and enzymic （i.e., ribulose-1,5-bisphosphate carboxylase/oxygenase （Rubisco）, phosphoenolpyruvate carboxylase （PEPCase）, and glutamine synthetase/glutamate synthetase （GS/GOGAT）） differences that develop when plants are treated with either nitrate or ammonium nitrogen forms are related to photosynthesis and photorespiration. The differences in photorespiration rate for plants treated with nitrate or ammonium are related to the conversion of citrate to 2-oxoglutarate （2-OG） and photorespiratory CO2 refixation.

关键词： ammonium nitrate nitrogen form photorespiration photosynthesis

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Expression of a bee venom phospholipase A_2 from Apis cerana cerana in the baculovirus-insect cell

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第5期11卷 342-349页

作者： Li-rong shen Mei-hui DING Li-wen ZHANG Wei-guang ZHANG Liang LIU Duo LI Department of Food Science and Nutrition Zhejiang University Hangzhou 310029 China Department of Agriculture and Natural Resources Delaware State University Dover DE 19901 USA

Bee venom phospholipase A2(BvPLA2) is a lipolytic enzyme that catalyzes the hydrolysis of the sn-2 acyl bond of glycerophospholipids to liberate free fatty acids and *** this work,a new BvPLA2(AccPLA2) gene from the Chinese honeybee(Apis cerana cerana) venom glands was inserted into bacmid to construct a recombinant transfer ***-5B-4(Tn) cells were transfected with the recombinant bacmid DNA for *** dodecylsulfate-polyacrylamide gel electrophoresis(SDS-PAGE) analysis revealed a double band with molecular weights of 16 and 18 *** of hexahistidine AccPLA2 fusion protein accumulated up to 5.32% of the total cellular *** AccPLA2 fusion protein was cross reactive with the anti-AmPLA2(BvPLA2 of the European honeybee,Apis mellifera) polyclonal *** reaction resulted in a double glycosylation band,which agrees with the band generated by the native AmPLA2 in Western blot *** PLA2 activity of the total extracted cellular protein in the hydrolyzing egg yolk is about 3.16 μmol/(min·mg).In summary,the recombinant AccPLA2 protein,a native BvPLA2-like structure with corresponding biological activities,can be glycosylated in Tn *** findings provided fundamental knowledge for potential genetic engineering to produce AccPLA2 in the pharmaceutical industry.

关键词： Apis cerana cerana Bee venom phospholipase A(BvPLA) Insect cell Expression

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Loss of the ubiquitin-conjugating enzyme Rad6B disturbs mitochondrial function and cellular homeostasis in mouse skin

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BIOCELL 2021年第3期45卷 761-772页

作者： LINGHUI YU rong shen YANAN GUO YANXUAN GUO CHEN LI YANFENG SONG DEGUI WANG Department of Anatomy and Histology School of Basic Medical SciencesLanzhou UniversityLanzhou730000China

Various factors can induce cell degeneration by altering the phenotype and metabolism of *** play an essential role in cellular homeostasis and function,rendering aging processes highly associated with mitochondrial function and ***,we describe an aging-prone phenotype of murine skin cells caused by depletion of Rad6B(Ube2b),an E2 ubiquitin-conjugating *** this study,using Masson’s trichrome,we showed that loss of Rad6B causes physiological structure changes in mouse skin with *** addition,a combination of western blotting experiments,transmission electron microscopy and employment of immunofluorescence staining revealed that depletion of Rad6B was characterized by an abnormal mitochondrial metabolic profile,including decreased mitochondrial biosynthesis and mitochondrial complex activities,increased ROS production and suppressed mitophagy resulting in metabolic *** together,these results highlight an important relationship between Rad6B and skin senescence,suggesting that Rad6B plays an indispensable role in maintaining a healthy mitochondrial network and intracellular homeostasis.

关键词： Rad6B Skin Mitochondria Respiratory chain Senescence

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New observations on the effect of camellia oil on fatty liver disease in rats

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2020年第8期21卷 657-667页

作者： Chun-xue LI Li-rong shen Department of Food Science and Nutrition College of Biosystems Engineering and Food ScienceZhejiang Key Laboratory for Agro-Food ProcessingZhejiang UniversityHangzhou 310058China

Camellia oil has become an important plant oil in China in recent years,but its effects on non-alcoholic fatty liver disease(NAFLD)have not been *** this study,the effects of camellia oil,soybean oil,and olive oil on NAFLD were evaluated by analyzing the fatty acid profiles of the plant oils,the serum lipids and lipoproteins of rats fed different oils,and by cytological and ultrastructural observation of the rats’*** of fatty acid profiles showed that the polyunsaturated fatty acid(PUFA)n-6/n-3 ratio was 33.33 in camellia oil,12.50 in olive oil,and 7.69 in soybean *** of serum lipids and lipoproteins of rats showed that the levels of total cholesterol and low-density lipoprotein cholesterol in a camellia oil-fed group(COFG)were lower than those in an olive oil-fed group(OOFG)and higher than those in a soybean oil-fed group(SOFG).However,only the difference in total cholesterol between the COFG and SOFG was statistically *** observation showed that the degree of lipid droplet(LD)accumulation in the hepatocytes in the COFG was lower than that in the OOFG,but higher than that in the *** analysis revealed that the size and number of the LDs in the hepatocytes of rats fed each of the three types of oil were related to the degree of damage to organelles,including the positions of nuclei and the integrity of mitochondria and endoplasmic *** results revealed that the effect of camellia oil on NAFLD in rats was greater than that of soybean oil,but less than that of olive *** the overall trend was that among the three oil diets,those with a lower n-6/n-3 ratio were associated with a lower risk of NAFLD,and the effect of camellia oil on NAFLD was not entirely related to the n-6/n-3 ratio and may have involved other *** provides new insights into the effect of oil diets on NAFLD.

关键词： Camellia oil Fatty acid Lipid droplet Hepatocyte ultrastructure Organelle

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Biased retro-proportional navigation law for interception of high-speed targets with angular constraint

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Defence Technology（防务技术） 2014年第1期10卷 60-65页

作者： Liang YAN Ji-guang ZHAO Huai-rong shen Yuan LI Academy of Equipment

A new guidance law, called biased retro proportional navigation(BRPN), is proposed. The guidance law is designed to intercept high-speed targets with angular constraint, which can be used for ballistic target interception. BRPN guidance law is defined, and the exact time-varying bias for a required impact angle is derived. Furthermore, the simulation results(trajectory, variation of navigation ratio, capture region, etc) are compared with those of biased proportional navigation(BPN), proportional navigation and retro-proportional navigation. The results show that,at the cost of a higher intercept time, BRPN demands lower terminal lateral acceleration and has larger capture region compared to BPN.

关键词：比例导引法角度约束拦截横向加速度制导律仿真结果时间成本冲击角

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