Genetic Diversity and Structure of Cordyceps sinensis Populations from Extensive Geographical Regions in China as Revealed by Inter-Simple Sequence Repeat Markers

Hong-Hui Liang,Zhou Cheng,Xiao-Ling Yang,Shan Li,Zu-Quan Ding,Tong-Shui Zhou,Wen-Ju Zhang,Jia-Kuan Chen 한국미생물학회 2008 The journal of microbiology Vol.46 No.5

Cordyceps sinensis is one of the most valuable medicinal caterpillar fungi native to China. However, its productivity is extremely limited and the species is becoming endangered. The genetic diversity of eighteen C. sinensis populations across its major distributing regions in China was evaluated by inter-simple sequence repeat (ISSR) markers. A total of 141 markers were produced in 180 individuals from the 18 populations, of which 99.3% were polymorphic. The low average of Shannon (0.104) and Nei index (0.07) of the 18 populations indicates that there are little genetic variations within populations. For all 18 populations, estimates of total gene diversity (HT), gene diversity within populations (HS), coefficient of genetic differentiation (GST), and gene flow (Nm) were 0.170, 0.071, 0.583, and 0.357, respectively. This pattern suggests that the genetic diversity of C. sinensis is low and most of the ISSR variations are found among populations with little gene exchange. The 18 populations are divided into five groups based on the genetic distance and the grouping pattern matches with the geographic distribution along the latitudinal gradient. The five groups show obvious difference in the GST and Nm values. Therefore, the genetic diversification of C. sinensis populations may be determined by geographic isolation and the combined effects of life history characters and the interaction with host insect species. The information illustrated by this study is useful for selecting in situ conservation sites of C. sinensis.

Investigating creep behavior of Ni–Cr–W alloy pressurized tube at 950 °C by using in-situ creep testing system

Zhong Yang,Lan Kuan-Che,Lee Hoon,Zhou Bomou,Wang Yong,Tsang D.K.L.,Stubbins James F. 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

The creep behavior of NieCreW alloy at 950 C has been investigated by a novel creep testing system which is capable of in-situ measurement of strain. Tubular specimens were pressurized with argon gas for effective stresses up to 32 MPa. Experimental results show that the thermal fatigue reduces the creep life of the tubular specimens and with the introduction of thermal cycling fatigue the primary stage disappears and the creep rate higher than the pure thermal creep (without thermal fatigue). Also the creep behavior of NieCreW alloy doesn't consist in the secondary stage. A new creep equation has been derived and implemented into finite element method. The results from the finite element analyses are in good agreement with the creep experiment.

Controlled crack propagation for atomic precision handling of wafer-scale two-dimensional materials

Shim, Jaewoo,Bae, Sang-Hoon,Kong, Wei,Lee, Doyoon,Qiao, Kuan,Nezich, Daniel,Park, Yong Ju,Zhao, Ruike,Sundaram, Suresh,Li, Xin,Yeon, Hanwool,Choi, Chanyeol,Kum, Hyun,Yue, Ruoyu,Zhou, Guanyu,Ou, Yunbo American Association for the Advancement of Scienc 2018 Science Vol.362 No.6415

<P><B>Cleaving with a metal handle</B></P><P>Using adhesive tape to pull off monolayers of two-dimensional (2D) materials is now a well-established approach. However, the flakes tend to be micrometer scale, and the creation of multilayer stacks for device application can be challenging and time consuming. Shim <I>et al.</I> show that monolayers of a variety of 2D materials, including molybdenum disulfide and hexagonal boron nitride, can be cleaved from multilayers grown as 5-centimeter-diameter wafers. The multilayer is capped with a nickel layer, which can be used to pull off the entire grown stack. The bottom of the stack is again capped with nickel, and a second round of cleaving leaves the monolayer on the bottom nickel layer. The monolayers could be transferred to other surfaces, which allowed the authors to make field-effect transistors with high charge-carrier mobilities.</P><P><I>Science</I>, this issue p. 665</P><P>Although flakes of two-dimensional (2D) heterostructures at the micrometer scale can be formed with adhesive-tape exfoliation methods, isolation of 2D flakes into monolayers is extremely time consuming because it is a trial-and-error process. Controlling the number of 2D layers through direct growth also presents difficulty because of the high nucleation barrier on 2D materials. We demonstrate a layer-resolved 2D material splitting technique that permits high-throughput production of multiple monolayers of wafer-scale (5-centimeter diameter) 2D materials by splitting single stacks of thick 2D materials grown on a single wafer. Wafer-scale uniformity of hexagonal boron nitride, tungsten disulfide, tungsten diselenide, molybdenum disulfide, and molybdenum diselenide monolayers was verified by photoluminescence response and by substantial retention of electronic conductivity. We fabricated wafer-scale van der Waals heterostructures, including field-effect transistors, with single-atom thickness resolution.</P>

Genetic diversity and population structure of the amylolytic yeast Saccharomycopsis fibuligera associated with Baijiu fermentation in China

Wang Ju-Wei,Han Pei-Jie,Han Da-Yong,Zhou Sen,Li Kuan,He Peng-Yu,Zhen Pan,Yu Hui-Xin,Liang Zhen-Rong,Wang Xue-Wei,Bai Feng-Yan 한국미생물학회 2021 The journal of microbiology Vol.59 No.8

The amylolytic yeast Saccharomycopsis fibuligera is a predominant species in starters and the early fermentation stage of Chinese liquor (Baijiu). However, the genetic diversity of the species remains largely unknown. Here we sequenced the genomes of 97 S. fibuligera strains from different Chinese Baijiu companies. The genetic diversity and population structure of the strains were analyzed based on 1,133 orthologous genes and the whole genome single nucleotide polymorphisms (SNPs). Four main lineages were recognized. One lineage contains 60 Chinese strains which are exclusively homozygous with relatively small genome sizes (18.55–18.72 Mb) and low sequence diversity. The strains clustered in the other three lineages are heterozygous with larger genomes (21.85–23.72 Mb) and higher sequence diversity. The genomes of the homozygous strains showed nearly 100% coverage with the genome of the reference strain KPH12 and the sub-genome A of the hybrid strain KJJ81 at the above 98% sequence identity level. The genomes of the heterozygous strains showed nearly 80% coverage with both the sub-genome A and the whole genome of KJJ81, suggesting that the Chinese heterozygous strains are also hybrids with nearly 20% genomes from an unidentified source. Eighty-three genes were found to show significant copy number variation between different lineages. However, remarkable lineage specific variations in glucoamylase and α-amylase activities and growth profiles in different carbon sources and under different environmental conditions were not observed, though strains exhibiting relatively high glucoamylase activity were mainly found from the homozygous lineage.

Remarkably efficient hydrolysis of cinnamaldehyde to natural benzaldehyde in amino acid ionic liquids

Duan-Jian Tao,Xiang-Shu Chen,Shu Xu,Feng-Feng Chen,Yan Zhou,Xin Zhao,Li-Li Yu,Kuan Huang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12

The hydrolysis of cinnamaldehyde to natural benzaldehyde was investigated systematically using tetramethylammonium- based amino acid ionic liquids as homogeneous catalysts. The results indicated that tetramethylammonium prolinate ([N1111][Pro]) can be a powerful catalyst for the highly efficient hydrolysis of cinnamaldehyde, in which natural benzaldehyde was obtained with almost 94% yield and over 99% selectivity in 1 h. Moreover, kinetic study showed that compared with other catalysts, the catalytic system of [N1111][Pro] has a lower activation energy of 38.30 kJ·mol−1 in the hydrolysis reaction, indicating superior catalytic performance of [N1111][Pro]. Quantum-mechanical calculations further manifested that such high performance originates from the cooperative catalysis of the secondary amino and carboxyl group in the anion [Pro].

낙엽기반 펠릿 내수성 강화 연구

고성민(Seong-Min Go),이명호(Myeong Ho Lee),이창현(Chang Hyeon Lee),주관(Kuan Zhou),간바야르(Ganbayar),성용주(Yong Joo Sung) 한국펄프·종이공학회 2021 한국펄프·종이공학회 학술발표논문집 Vol.2021 No.10

Optimized Assembly of Micro-/Meso-/Macroporous Carbon for Li–S Batteries

Qiong Tang,Heqin Li,Min Zuo,Jing Zhang,Yiqin Huang,Peiwen Bai,Jiaqi Xu,Kuan Zhou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.2

In order to explore the effect of hierarchical porous carbon on the performances of Li–S batteries, we synthesized three kinds of micro-/meso-/macroporous carbon materials with different pore properties by facile hard-template method. Different from the majority of reports on porous carbon ensuing large specific surface area (SSA) and total pore volume, it was found that in the case of identically high sulfur content, the pore size distribution substantially influences the performances of Li–S batteries rather than the SSA and total pore volume. Furthermore, in the assembly of micro-/meso-/macropores, the micropore volume ratio to the total pore volume is dominant to the capabilities of batteries. Among the samples, the porous carbon carbonized with the precursor of sucrose at 950℃ presents the highest initial discharge specific capacity of 1327 mAh/g and retention of 630 mAh/g over 100 cycles at 0.2C rate along with the best rate capability. This sample possesses the largest micropore volume ratio of 47.54% but a medium SSA of 1217 m2 /g and inferior total pore volume of 0.54 cm3 /g. The abundant micropores effectively improve the conductivity of dispersed sulfur particles, inhibit the loss of sulfur series and enable the cathode to exhibit superior electrochemical performances.