Synthesis and Magnetic Properties of FeCo Alloy Nanowires via AC Frequency Conversion Electrodeposition

Lirong Wang,Shunzhen Feng,Tingting Lu,Lizhen Zhen,Jiwei Zhang,Lihu Liu 한국자기학회 2022 Journal of Magnetics Vol.27 No.3

Binary alloy nanowires of Fe3Co7 system are synthesized in the highly ordered porous anodic aluminum oxide (PAA) templates by AC frequency (5, 50, 120, and 200 Hz) conversion electrodeposition method. High resolution field emission transmission electron microscope (HRTEM) and Lorenz TEM (LTEM) were used to study the morphology and the magnetic domain structure of the Fe3Co7 alloy nanowires, respectively. Magnetic measurements showed that the M-H curves presented a discontinuity in a restricted magnetic field, but with high squareness (about 90 %). Quantitative local measurements of the magnetic properties of the nanowires are explored by differential phase contrast (DPC) imaging. The magnetic properties, however, were significantly affected by the AC frequency, which is correlated with the specific magnetic structure formation of Bloch line. We reported herein a detailed investigation on Fe3Co7 alloy nanowires and their magnetic properties.

Characteristic and role of chromosomal type II toxin-antitoxin systems locus in Enterococcus faecalis ATCC29212

Li Zhen,Shi Chao,Gao Shanjun,Zhang Xiulei,Lu Di,Liu Guangzhi 한국미생물학회 2020 The journal of microbiology Vol.58 No.12

The Gram-positive bacterium Enterococcus faecalis is currently one of the major pathogens of nosocomial infections. The lifestyle of E. faecalis relies primarily on its remarkable capacity to face and survive in harsh environmental conditions. Toxin-antitoxin (TA) systems have been linked to the growth control of bacteria in response to adverse environments but have rarely been reported in Enterococcus. Three functional type II TA systems were identified among the 10 putative TA systems encoded by E. faecalis ATCC29212. These toxin genes have conserved domains homologous to MazF (DR75_ 1948) and ImmA/IrrE family metallo-endopeptidases (DR75_ 1673 and DR75_2160). Overexpression of toxin genes could inhibit the growth of Escherichia coli. However, the toxin DR75_1673 could not inhibit bacterial growth, and the bacteriostatic effect occurred only when it was coexpressed with the antitoxin DR75_1672. DR75_1948–DR75_1949 and DR75_ 160–DR75_2161 could maintain the stable inheritance of the unstable plasmid pLMO12102 in E. coli. Moreover, the transcription levels of these TAs showed significant differences when cultivated under normal conditions and with different temperatures, antibiotics, anaerobic agents and H2O2. When DR75_2161 was knocked out, the growth of the mutant strain at high temperature and oxidative stress was limited. The experimental characterization of these TAs loci might be helpful to investigate the key roles of type II TA systems in the physiology and environmental stress responses of Enterococcus.

Surface oxidation and thermoelectric properties of indium-doped tin telluride nanowires

Li, Zhen,Xu, Enzhi,Losovyj, Yaroslav,Li, Nan,Chen, Aiping,Swartzentruber, Brian,Sinitsyn, Nikolai,Yoo, Jinkyoung,Jia, Quanxi,Zhang, Shixiong The Royal Society of Chemistry 2017 Nanoscale Vol.9 No.35

<P>The recent discovery of excellent thermoelectric properties and topological surface states in SnTe-based compounds has attracted extensive attention in various research areas. Indium doped SnTe is of particular interest because, depending on the doping level, it can either generate resonant states in the bulk valence band leading to enhanced thermoelectric properties, or induce superconductivity that coexists with topological states. Here we report on the vapor deposition of In-doped SnTe nanowires and the study of their surface oxidation and thermoelectric properties. The nanowire growth is assisted by Au catalysts, and their morphologies vary as a function of substrate position and temperature. Transmission electron microscopy characterization reveals the formation of an amorphous surface in single crystalline nanowires. X-ray photoelectron spectroscopy studies suggest that the nanowire surface is composed of In2O3, SnO2, Te and TeO2which can be readily removed by argon ion sputtering. Exposure of the cleaned nanowires to atmosphere leads to rapid oxidation of the surface within only one minute. Characterization of electrical conductivity<I>σ</I>, thermopower<I>S</I>, and thermal conductivity<I>κ</I>was performed on the same In-doped nanowire which shows suppressed<I>σ</I>and<I>κ</I>but enhanced<I>S</I>yielding an improved thermoelectric figure of merit<I>ZT</I>compared to the undoped SnTe.</P>

Pattern recognition receptors and their nano-adjuvants for cancer immunotherapy

LI ZHEN,Rana Isra,Park Gyungdeuk,이진우,Park Chae Eun,Nam Jutaek 한국약제학회 2023 Journal of Pharmaceutical Investigation Vol.53 No.5

Background Pattern recognition receptors (PRRs) are crucial immune modulators that orchestrate innate and adaptive immune systems for the regulation of inflammatory responses. Several PRR families and their ligands associated with immune modulation have been identified, which promoted the development of natural and synthetic PRR agonistic ligands as adjuvants in immunotherapy applications. However, conventional adjuvants are mainly based on small molecules, peptides, lipids, and oligonucleotides, which suffer from unfavorable drug-like properties for in vivo applications, including vulnerability to biodegradation, undesirable pharmacokinetic profiles, and poor cellular uptake. Nanoparticle formulation is a promising approach for addressing the issues with conventional adjuvants. Area covered This review aims to provide a broad understanding of nano-adjuvants utilized in cancer immunotherapy. For this purpose, we introduce the background, summarize the current knowledge on PRRs and their ligands for some representative classes, and highlight various nanoparticle platforms that are utilized to construct nano-adjuvants in cancer immunotherapy. We also discuss some design considerations for optimal nano-adjuvant formulations with potent adjuvant activity and desired in vivo performance. Expert opinion Nanoparticles provide a robust and versatile platform to shape conventional adjuvants into more drug-like formulations, and the preclinical studies and clinical trials have demonstrated their potential in cancer immunotherapy. The emergence of cancer immunotherapy in clinics will fuel continuous efforts toward highly efficient nano-adjuvant systems that can strongly boost the antitumor immune responses in cancer immunotherapy. The accumulated knowledge gained through the progress will provide important insights into optimal nano-adjuvant formulations and potentially guide their clinical translation.

Molecular Cloning, mRNA Expression, and Localization of the G-protein Subunit Galphaq in Sheep Testis and Epididymis

Li, Zhen,Lu, Jieli,Sun, Xiaowei,Pang, Quanhai,Zhao, Yiwen Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.12

The reproductive function of G-protein subunit Galphaq (GNAQ), a member of the G protein alpha subunit family, has been extensively studied in humans and rats. However, no data is available on its status in ruminants. The objectives of this study were to evaluate the expression pattern of the GNAQ in the testis and epididymis of sheep by polymerase chain reaction (PCR). The mRNA expression levels were detected by real-time fluorescent quantitative PCR, and cellular localization of GNAQ in the testis and epididymis was examined by immunohistochemistry. Additionally, GNAQ protein was qualitatively evaluated via western blot, with the results indicating that similarities between GNAQ mRNA levels from sheep was highly conserved with those observed in Bos taurus and Sus scrofa. Our results also indicated that GNAQ exists in the caput and cauda epididymis of sheep, while GNAQ in the testis and epididymis was localized to Leydig cells, spermatogonial stem cells, spermatocytes, Sertoli cells, spermatid, principal cells, and epididymis interstitial cells. The concentrations of GNAQ mRNA and protein in the caput and cauda epididymis were significantly greater than those observed in the corpus epididymis (p<0.01) and testis (p<0.05). Our results indicated that GNAQ exists at high concentrations in the caput and cauda epididymis of sheep, suggesting that GNAQ may play an important role in gonad development and sperm maturation.