Vertically Aligned WO3–CuO Core–Shell Nanorod Arrays for Ultrasensitive NH3 Detection

Wenjun Yan,Ming Hu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.10

Vertically aligned WO3–CuO core–shell nanorod arrays for NH3 sensing are prepared. The sensor is fabricated by preparing WO3–CuO nanorod arrays directly on silicon wafer with interdigital Pt electrodes. The WO3–CuO nanorod arrays are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The sensor based on the vertically aligned WO3–CuO nanorod arrays exhibits ultrasensitive NH3 detection, indicating p-type behavior. The optimum sensing temperature is found to be about 150 ℃. Both response and recovery time to NH3 ranging from 50 ppm to 500 ppm are around 10–15 s. A possible NH3 sensing mechanism of the vertically aligned hybrid nanorod arrays is proposed.

Sizing Performance Improvement of Cotton Yarns Pretreated with UV Irradiation

Wenjun Yan,Bo Zhu,Weidong Gao 한국섬유공학회 2022 Fibers and polymers Vol.23 No.11

UV irradiation technology has the advantages of ease operation, affordable, and clean production. This paperfocused on the wettability improvement of cotton yarns by UV irradiation, and proposed UV irradiation pretreatment methodto improve the sizing performance of cotton yarns. The surface elemental composition and molecular structure before andafter UV irradiation were characterized. The effects of UV irradiation pretreatment intensity and time on apparent properties,weight, wettability and mechanical properties of raw cotton yarns were analyzed. The impact of UV irradiation pretreatmentprocess on sized yarns performance including mechanical properties, hairiness, yarn evenness and size pick-up were studied. Then, the mechanical properties of the sized yarns after alkali desizing were investigated. The results showed that UVirradiation pretreatment can introduce oxygen-containing polar groups on the cotton yarns. Meanwhile, it had a certaindegradation effect on the surface of the cotton yarns, which resulted in wax removed, roughness improvement and exposureof cellulose. The above reasons jointly caused the wettability improvement of raw cotton yarns after UV irradiation. Compared with the unpretreated sized ones, the breaking strength, breaking elongation and abrasion resistance of the UVirradiation pretreated sized yarns was greatly enhanced by 20.13 %, 20.54 % and 103.49 % respectively. The hairiness wasreduced by 88.23 %, and the yarn evenness was improved by 6.74 %. It presented the optimized sizing performance when theyarns were pretreated at UV irradiation intensity of 142.5 mW/cm2 for 120 min. After desizing, the decline amplitude waslittle between unpretreated and UV irradiation pretreated yarns.

Progranulin Controls Sepsis via C/EBPα-Regulated <i>Il10</i> Transcription and Ubiquitin Ligase/Proteasome-Mediated Protein Degradation

Yan, Wenjun,Ding, Aihao,Kim, Ha-Jeong,Zheng, Hua,Wei, Fang,Ma, Xiaojing American Association of Immunologists 2016 Journal of Immunology Vol. No.

<P>Progranulin (PGRN) is a widely expressed, pleiotropic protein that is involved in diverse biological processes, including cellular proliferation, neuron development, and wound healing. However, the role of PGRN in the regulation of pathogen-induced systemic inflammation and the mechanisms involved have not been established. In this study, we show that PGRN-deficient mice display heightened mortality in models of polymicrobial sepsis and endotoxinemia, with increased tissue levels of inflammatory cytokines and reduced IL-10 production. Conversely, administration of rPGRN decreases the susceptibility of PGRN-deficient mice to LPS-induced endotoxemic shock and augments IL-10 production by LPS-activated macrophages in a TNFR-dependent manner. Molecular analysis reveals a direct role of the transcription factor C/EBP alpha in PGRN-regulated IL-10 expression. C/EBP alpha-deficient macrophages produce less IL-10 in response to LPS. Furthermore, mice deficient in C/EBP alpha in hematopoietic cells are highly vulnerable to LPS-induced septic shock. Lastly, the defective IL-10 production by PGRN-deficient cells is primarily due to reduced C/EBP alpha protein stability via the E3 ubiquitin-conjugating enzyme E6AP and proteasome-mediated degradation. To our knowledge, this study provides the first evidence that PGRN is a nonredundant regulator of systemic inflammation via modulating the levels and activity of C/EBP alpha, IL-10, and the ubiquitin-proteasome proteolysis pathway. The results bear strong and profound implications for PGRN insufficiency and its mutation-associated systemic and organ-specific inflammatory human diseases.</P>

Effect of Au on the Performance of Porous Silicon/V2O5 Nanorods Heterojunctions to NO2 Gas

Wenjun Yan,Minghui Zhou,Jiran Liang,Dengfeng Wang,Yulong Wei,Yuxiang Qin 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.7

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25℃), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.

Well-designed Te/SnS₂/Ag artificial nanoleaves for enabling and enhancing visible-light driven overall splitting of pure water

Yan, Changzeng,Xue, Xiaolan,Zhang, Wenjun,Li, Xiaojie,Liu, Juan,Yang, Songyuan,Hu, Yi,Chen, Renpeng,Yan, Yaping,Zhu, Guoyin,Kang, Zhenhui,Kang, Dae Joon,Liu, Jie,Jin, Zhong unknown 2017 Nano energy Vol.39 No.-

<P><B>Abstract</B></P> <P>To produce hydrogen and oxygen from photocatalytic overall splitting of pure water provides a promising green route to directly convert solar energy to clean fuel. However, the design and fabrication of high-efficiency photocatalyst is challenging. Here we present that by connecting different nanostructures together in a rational fashion, components that cannot individually split water into H<SUB>2</SUB> and O<SUB>2</SUB> can work together as efficient photocatalyst with high solar-to-hydrogen (STH) energy conversion efficiency and avoid the use of any sacrificial reagent. Specifically, Te/SnS<SUB>2</SUB>/Ag artificial nanoleaves (ANLs) consist of ultrathin SnS<SUB>2</SUB> nanoplates grown on Te nanowires and decorated with numerous Ag nanoparticles. The appropriate band structure of Te/SnS<SUB>2</SUB> p-n junctions and the surface plasmon resonance of Ag nanoparticles synergistically enhance the quantum yield and separation efficiency of electron-hole pairs. As a result, Te/SnS<SUB>2</SUB>/Ag ANLs enable visible-light driven overall water-splitting without any sacrificial reagent and exhibit high H<SUB>2</SUB> and O<SUB>2</SUB> production rates of 332.4 and 166.2μmolh<SUP>−1</SUP>, respectively. Well-preserved structure after long-term measurement indicates its high stability. It represents a feasible approach for direct H<SUB>2</SUB> production from only sunlight, pure water, and rationally-designed ANL photocatalysts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Te/SnS<SUB>2</SUB>/Ag ANLs heterostructure is prepared to catalyze overall water splitting. </LI> <LI> The catalyst show impressive H<SUB>2</SUB> and O<SUB>2</SUB> production rate under visible light. </LI> <LI> The structure and efficiency of catalyst shows no degradation after 10 days. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

The Choice between Might and Right: Rule of Law in International Relations

Wenjun Yan 이준국제법연구원 2022 China and WTO Review Vol.8 No.1

Identification of Coccoidal Bacteria in Traditional Fermented Milk Products from Mongolia, and the Fermentation Properties of the Predominant Species, Streptococcus thermophilus

Yan Ren,Wenjun Liu,Heping Zhang 한국축산식품학회 2015 한국축산식품학회지 Vol.35 No.5

The objective of this study was to identify the coccoidal bacteria present in 188 samples of fermented yaks’, mares’ and cows’ milk products collected from 12 different regions in Mongolia. Furthermore, we evaluated the fermentation properties of ten selected isolates of the predominant species, Streptococcus (S.) thermophiles, during the process of milk fermentation and subsequent storage of the resulting yoghurt at 4°C. Overall, 159 isolates were obtained from 188 samples using M17 agar. These isolates were presumed to be lactic acid bacteria based on their gram-positive and catalase-negative properties, and were identified to species level using 16S rRNA gene sequence analysis. These coccoid isolates were distributed in four genera and six species: Enterococcus (E.) durans, Enterococcus (E.) faecalis, Lactococcus (Lac.) subsp. lactis, Leuconostoc (Leuc.) lactis, Leuconostoc (Leuc.) mesenteroides. subsp. mesenteroides and S. thermophilus. Among these S. thermophilus was the most common species in most samples. From evaluation of the fermentation characteristics (viable counts, pH, titratable acidity [TA]) of ten selected S. thermophilus isolates we could identify four isolates (IMAU 20246, IMAU20764, IMAU20729 and IMAU20738) that were fast acid producers. IMAU20246 produced the highest concentrations of lactic acid and formic acid. These isolates have potential as starter cultures for yoghurt production.

Intercalation of Europium Inclusion Complex of β-Cyclodextrin into Layered Double Hydroxides Through Layer-By-Layer Assembly and Its Luminescent Properties

Wenjun Zhang,Yi Chen,Yanlin Li,Sumin Guan,Yan Chen,Qian-Qian Yang,Lu Liu,Qing-Chen Xue,Yu-Cui Guang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.10

"In this work, organic–inorganic hybrid ultrathin transparent films (UTFs), produced by layer-by-layer (LBL) assembly of the europium inclusion complex of β-cyclodextrin ( β-CD) and Mg–Al layered double hydroxide (MgAl–NO3–LDHs) nanosheets, are reported. UV-visible (UV-Vis) absorption and fluorescence spectroscopy show orderly growth of the europium inclusion complex of β-CD/layered double hydroxide (EICC/LDH) films with an increasing number of deposition cycles. X-ray diffraction and scanning electron microscopy measurements indicate that the films feature periodic layered structures with uniform surface morphology. Moreover, when EICC is assembled with inorganic rigid LDH nanosheets, the lifetimes are prolonged due to the isolation effect, and the UTFs are transparent with high brightness, which indicate that these films could serve as new optical materials."

Identification of Coccoidal Bacteria in Traditional Fermented Milk Products from Mongolia, and the Fermentation Properties of the Predominant Species, Streptococcus thermophilus

Ren, Yan,Liu, Wenjun,Zhang, Heping Korean Society for Food Science of Animal Resource 2015 한국축산식품학회지 Vol.35 No.5

The objective of this study was to identify the coccoidal bacteria present in 188 samples of fermented yaks’, mares’ and cows’ milk products collected from 12 different regions in Mongolia. Furthermore, we evaluated the fermentation properties of ten selected isolates of the predominant species, Streptococcus (S.) thermophiles, during the process of milk fermentation and subsequent storage of the resulting yoghurt at 4℃. Overall, 159 isolates were obtained from 188 samples using M17 agar. These isolates were presumed to be lactic acid bacteria based on their gram-positive and catalase-negative properties, and were identified to species level using 16S rRNA gene sequence analysis. These coccoid isolates were distributed in four genera and six species: Enterococcus (E.) durans, Enterococcus (E.) faecalis, Lactococcus (Lac.) subsp. lactis, Leuconostoc (Leuc.) lactis, Leuconostoc (Leuc.) mesenteroides. subsp. mesenteroides and S. thermophilus. Among these S. thermophilus was the most common species in most samples. From evaluation of the fermentation characteristics (viable counts, pH, titratable acidity [TA]) of ten selected S. thermophilus isolates we could identify four isolates (IMAU 20246, IMAU20764, IMAU20729 and IMAU20738) that were fast acid producers. IMAU20246 produced the highest concentrations of lactic acid and formic acid. These isolates have potential as starter cultures for yoghurt production.

Isolation and Identification of Lactic Acid Bacteria from Traditional Dairy Products in Baotou and Bayannur of Midwestern Inner Mongolia and q-PCR Analysis of Predominant Species

Dan Wang,Wenjun Liu,Yan Ren,Liangliang De,Donglei Zhang,Yanrong Yang,Qiuhua Bao,Heping Zhang,Bilige Menghe 한국축산식품학회 2016 한국축산식품학회지 Vol.36 No.4

In this study, traditional culture method and 16S rRNA gene analysis were applied to reveal the composition and diversity of lactic acid bacteria (LAB) of fermented cow milk, huruud and urum from Baotou and Bayannur of midwestern Inner Mongolia. Also, the quantitative results of dominant LAB species in three different types of dairy products from Baotou and Bayannur were gained by quantitative polymerase chain reaction (q-PCR) technology. Two hundred and two LAB strains isolated from sixty-six samples were identified and classified into four genera, namely Enterococcus, Lactococcus, Lactobacillus, Leuconostoc, and twenty-one species and subspecies. From these isolates, Lactococcus lactis subsp. lactis (32.18%), Lactobacillus plantarum (12.38%) and Leuconosto mesenteroides (11.39%) were considered as the dominated LAB species under the condition of cultivating in MRS and M17 medium. And the q-PCR results revealed that the number of dominant species varied from samples to samples and from region to region. This study clearly shows the composition and diversity of LAB existing in fermented cow milk, huruud and urum, which could be considered as valuable resources for LAB isolation and further probiotic selection.