Comparative genomics analysis of Pediococcus acidilactici species

Li Zhenzhen,Song Qi,Wang Mingming,Ren Junli,Liu Songling,Zhao Shancen 한국미생물학회 2021 The journal of microbiology Vol.59 No.6

Pediococcus acidilactici is a reliable bacteriocin producer and a promising probiotic species with wide application in the food and health industry. However, the underlying genetic features of this species have not been analyzed. In this study, we performed a comprehensive comparative genomic analysis of 41 P. acidilactici strains from various ecological niches. The bacteriocin production of 41 strains were predicted and three kinds of bacteriocin encoding genes were identified in 11 P. acidilactici strains, namely pediocin PA-1, enterolysin A, and colicin-B. Moreover, whole-genome analysis showed a high genetic diversity within the population, mainly related to a large proportion of variable genomes, mobile elements, and hypothetical genes obtained through horizontal gene transfer. In addition, comparative genomics also facilitated the genetic explanation of the adaptation for host environment, which specify the protection mechanism against the invasion of foreign DNA (i.e. CRISPR/Cas locus), as well as carbohydrate fermentation. The 41 strains of P. acidilactici can metabolize a variety of carbon sources, which enhances the adaptability of this species and survival in different environments. This study evaluated the antibacterial ability, genome evolution, and ecological flexibility of P. acidilactici from the perspective of genetics and provides strong supporting evidence for its industrial development and application.

Effect of Mg Content on the Damping Behavior of Al–Mg Alloys

Zhenzhen Li,Hongge Yan,Jihua Chen,Weijun Xia,Bin Su,Lu Zhao,Min Song 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

This article investigated the effect of Mg content (4.5, 6.5 and 9.2, in wt%) on the damping capacities of Al–Mg alloys. The results indicate that the damping behavior can be divided into three regions. Region I refers to the low strain amplituderegion (ε < 5 × 10−5), where the damping capacity decreases with increasing the Mg content and has almost no relation withthe strain amplitude. Region II is the middle strain amplitude region (5 × 10−5 < ε < 8 × 10−4), where the damping capacityincreases rapidly with the strain. Region III refers to the high strain amplitude region (8 × 10−4 < ε < 2 × 10−3), where thedamping capacity remains constant and is independent of the strain when the strain is high enough, but increases with the Mgcontent. The damping values Q−1 of Al–4.5Mg, Al–6.5Mg and Al–9.2Mg alloys are 0.01501 ± 0.00032, 0.01633 ± 0.00032and 0.01862 ± 0.00119 at the strain of 1 × 10−3, respectively. The damping capacity in Region I is mainly determined bythe lattice distortion caused by Mg addition and the restoring force caused by pinning points and Suzuki segregation. Theextended dislocations break away from the pinning effect of Mg atoms and become moveable in Region II, and the movementof extended dislocations is the dominant damping mechanism in Region III.

Ginsenosides: potential therapeutic source for fibrosis-associated human diseases

Li, Xiaobing,Mo, Nan,Li, Zhenzhen The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.3

Tissue fibrosis is an eventual pathologic change of numerous chronic illnesses, which is characterized by resident fibroblasts differentiation into myofibroblasts during inflammation, coupled with excessive extracellular matrix deposition in tissues, ultimately leading to failure of normal organ function. Now, there are many mechanistic insights into the pathogenesis of tissue fibrosis, which facilitate the discovery of effective antifibrotic drugs. Moreover, many chronic diseases remain a significant clinical unmet need. For the past five years, many research works have undoubtedly addressed the functional dependency of ginsenosides in different types of fibrosis and the successful remission in various animal models treated with ginsenosides. Caveolin-1, interleukin, thrombospondin-1 (TSP-1), liver X receptors (LXRs), Nrf2, microRNA-27b, PPARδ-STAT3, liver kinase B1 (LKB1)-AMPK, and TGF-β1/Smads are potential therapy targeting using ginsenosides. Ginsenosides can play a targeting role and suppress chronic inflammatory response, collagen deposition, and epitheliale-mesenchymal transition (EMT), as well as myofibroblast activation to attenuate fibrosis. In this report, our aim was to focus on the therapeutic prospects of ginsenosides in fibrosis-related human diseases making use of results acquired from various animal models. These findings should provide important therapeutic clues and strategies for the exploration of new drugs for fibrosis treatment.

Tertiary Amination/Hydroxypropylsulfonation of Cornstarch to Improve the Adhesion-to-Fibers and Film Properties for Warp Sizing

Wei Li,Zhenzhen Xu,Zongqian Wang,Changlong Li,Quan Feng,Yanan Zhu 한국섬유공학회 2018 Fibers and polymers Vol.19 No.7

To investigate the effects of tertiary amination/hydroxypropylsulfonation on the adhesion-to-fibers and film properties of corn starch for warp sizing, a series of tertiary aminated and hydroxypropylsulfonated corn starch (TAHPSS) samples were prepared by the tertiary amination and hydroxypropylsulfonation of acid-hydrolyzed corn starch (AHS) with 2- dimethylaminoethyl chloride hydrochloride (DMC-HCl) and 3-chloro-2-hydroxy-1-propanesulfonic acid sodium salt (CHPS-Na) simultaneously. The adhesion was evaluated by measuring the bonding force of starch to the fibers. The film properties were investigated in terms of tensile strength, breaking elongation, degree of crystallinity, and moisture regain. The results showed that tertiary amination/hydroxypropylsulfonation was able to increase bonding forces of starch to cotton and polyester fibers, enhance breaking elongation and moisture regain of the starch film and to decrease the tensile strength and degree of crystallinity of the film, thereby improving the adhesion and reducing film brittleness. Increasing the level of tertiary amination/hydroxypropylsulfonation was favorable for gradually improving the adhesion and decreasing the brittleness. The TAHPSS showed potential for use in cotton warp sizing.

Improvement of the Steroid Dihydroxylation Efficiency from Dehydroepiandrosterone Using a Substrate Pre-induction Biotransformation Process

Hui Li,Zhenzhen Fu,Heng Li,Wenfang Dou,Jinsong Shi,Zhenghong Xu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.3

This study investigated the effects of hydroxylase cyptochrome P450 inducers on the efficiency of the biotransformation of dehydroepiandrosterone (DHEA) to 3β, 7α, 15α-trihydroxy-5-androsten-17-one (7α,15α-diOHDHEA)by Colletotrichum lini ST-1. Special attention was given to the substrate DHEA being the best inducer and the fact that it could improve the yield of 7α, 15α-diOHDHEA. Based on the effects of the DHEA pre-induction phases and additional concentrations on 7α, 15α-diOHDHEA production, a substrate pre-induction process was established as follows: 2 g/L DHEA was added for the first time after 12 h of inoculation, followed by the second addition of 6 g/L DHEA after 12 h later. The results showed that this substrate pre-induction process improved the content of cytochrome P450 and that the 7α, 15α-diOH-DHEA yield reached 90.1%, which was 26.9%higher than that obtained in the original process.

Bimodal-Structured Al–Mg Alloy with High Strength and Ductility Processed by High Strain Rate Rolling at Medium Temperature

Xinyu Li,Weijun Xia,Jihua Chen,Hongge Yan,Zhenzhen Li,Bin Su,Min Song 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

A bimodal grain distribution is generated in the Al-6.5Mg alloy deformed by high strain rate rolling (HSRR) at 320 °C, inwhich the fine grains with the average size of 2.1 μm and the coarse grains with the size of hundreds of microns containingultrafine sub-grains are developed. The deformed microstructures are detected by transmission electron microscopy, X-raydiffraction and electron backscattered diffraction. High strength and considerable ductility are achieved in the HSRRed alloyand the high strength is ascribed to solution strengthening, grain (sub-grain) strengthening and dislocation strengthening. The grain (sub-grain) strengthening is the dominant contributor (~ 146 ± 6 MPa) for yield strength. The generation of newfine grains is primarily observed along the deformation bands related to the high Mg solid content and the high strain rate at320 °C. The dynamic recrystallization related to the deformation bands is proposed to build the bimodal grain distributionfor achieving high strength and considerable ductility.

Ginsenosides: potential therapeutic source for fi brosis-associated human diseases

Xiaobing Li,Nan Mo,Zhenzhen Li 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.3

Tissue fibrosis is an eventual pathologic change of numerous chronic illnesses, which is characterized byresident fibroblasts differentiation into myofibroblasts during inflammation, coupled with excessiveextracellular matrix deposition in tissues, ultimately leading to failure of normal organ function. Now,there are many mechanistic insights into the pathogenesis of tissue fibrosis, which facilitate the discoveryof effective antifibrotic drugs. Moreover, many chronic diseases remain a significant clinical unmetneed. For the past five years, many research works have undoubtedly addressed the functionaldependency of ginsenosides in different types of fibrosis and the successful remission in various animalmodels treated with ginsenosides. Caveolin-1, interleukin, thrombospondin-1 (TSP-1), liver X receptors(LXRs), Nrf2, microRNA-27b, PPARd-STAT3, liver kinase B1 (LKB1)-AMPK, and TGF-b1/Smads are potentialtherapy targeting using ginsenosides. Ginsenosides can play a targeting role and suppress chronicinflammatory response, collagen deposition, and epithelialemesenchymal transition (EMT), as well asmyofibroblast activation to attenuate fibrosis. In this report, our aim was to focus on the therapeuticprospects of ginsenosides in fibrosis-related human diseases making use of results acquired from variousanimal models. These findings should provide important therapeutic clues and strategies for theexploration of new drugs for fibrosis treatment.

NOx removal by non-thermal plasma at low temperatures with amino groups additives

Zhenzhen Guan,Jian-Xing Ren,Dezhen Chen,Liu Hong,Fangqin Li,Du Wang,Yuanhuang Ouyang,Yang Gao 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.11

NOx removal from flue gas using direct current (DC) narrow pulsed discharge-induced non-thermal plasma (NTP) was experimentally investigated. Factors such as additives, NOx initial concentrations, residence time, reaction temperatures inside the NTP reactor, and so on were investigated to evaluate their effects on NOx removal efficiencies. The focus was on the effects of additives containing amino groups. The results showed that H2O addition enhanced NOx removal, NH3 could further increase the NOx removal efficiencies under the same conditions without an obvious NH3 slip, and N2H4 was the most effective additive by reducing NOx to N2. X-Ray diffraction (XRD) analysis of the products collected from the NTP reactor demonstrated that NOx removal inside the NTP reactor was mainly based on NOx oxidation when ammonia or H2O was used as an additive, while NOx removal was mainly based on NOx reduction with the N2H4 additive.

DTN Routing with Back-Pressure based Replica Distribution

Zhenzhen Jiao,Rui Tian,Baoxian Zhang,Cheng Li 한국통신학회 2014 Journal of communications and networks Vol.16 No.4

Replication routing can greatly improve the data deliveryperformance by enabling multiple replicas of the same packet tobe transmitted towards its destination simultaneously. It has beenstudied extensively recently and is now a widely accepted routingparadigm in delay tolerant networks (DTNs). However, in thisfield, the issue of how to maximize the utilization efficiency of limitedreplication quota in a resource-saving manner and thereforemaking replication routing to be more efficient in networks withlimited resources has not received enough attention. In this paper,we propose a DTN routing protocol with back-pressure basedreplica distribution. Our protocol models the replica distributionproblem from a resource allocation perspective and it utilizes theidea of back-pressure algorithm, which can be used for providingefficient network resource allocation for replication quota assignmentamong encountered nodes. Simulation results demonstratethat the proposed protocol significantly outperforms existing replicationrouting protocols in terms of packet delay and delivery ratio.

Mitigation and Mechanism of Tin Whisker on Micro-bumps by Hard and Soft Underfills

Zhenzhen Shan,Ke Lin,Anmin Hu,Ming Li 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.6

It is the first time that the mitigation and mechanism of tin whisker on micro-bumps by different types of underfills are investigated under high temperature and humidity (55 ℃/88% RH) storage. Hard epoxy, soft silicone and polyurethane are selected as underfills to spin-coat the 10 μm-diameter and 20 μm-pitch Cu/Ni/SnAg micro-bumps. After six-month storage, underfills exhibite a good mitigation effect despite the surface decomposition, delamination, cracks and voids in varying degrees. Compared with the micro-bumps without underfill, the probability of whisker or hillock and oxidation or corrosion in micro-bumps is reduced by up to 66% and 96%, respectively. Based on the statistics and characterization results, the mitigation mechanism of tin whisker by underfills is proposed. The diameter and critical length of tin whisker are discussed as well to estimate its buckle or penetrate growth. Besides, several underfills failures are summarized. The findings are of great significance to the study of tin whisker mitigation on micro-bumps and provide insights into the reliability of advanced packaging.