Nonradiative energy transfer between colloidal quantum dot-phosphors and nanopillar nitride LEDs.

Zhang, Fan,Liu, Jie,You, Guanjun,Zhang, Chunfeng,Mohney, Suzanne E,Park, Min Joo,Kwak, Joon Seop,Wang, Yongqiang,Koleske, Daniel D,Xu, Jian Optical Society of America 2012 Optics express Vol.20 No.2

<P>We present in this communication our study of the nonradiative energy transfer between colloidal quantum dot (QD) phosphors and nitride nanopillar light emitting diodes (LEDs). An epitaxial p-i-n InGaN/GaN multiple quantum-well (QW) heterostructure was patterned and dry-etched to form dense arrays of nanopillars using a novel etch mask consisting of self-assembled In3Sn clusters. Colloidal QD phosphors have been deposited into the gaps between the nanopillars, leading to sidewall coupling between the QDs and InGaN QW emitters. In this approach, close QW-QD contact and a low-resistance design of the LED contact layer were achieved simultaneously. Strong non-radiative energy transfer was observed from the InGaN QW to the colloidal QD phosphors, which led to a 263% enhancement in effective internal quantum efficiency for the QDs incorporated in the nanopillar LEDs, as compared to those deposited over planar LED structures. Time-resolved photoluminescence was used to characterize the energy transfer process between the QW and QDs. The measured rate of non-radiative QD-QW energy-transfer agrees well with the value calculated from the quantum efficiency data for the QDs in the nanopillar LED.</P>

Antioxidant and Antigenotoxic Activities of Ethanol Extracts from Rhus chinensis Mill Leaves

Zhenyu Qiu,Mingli Tang,Guanjun Deng,Hao Yang,Xuan Zhang,Shengwei Huang,Lifang Wu 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.4

Ethanol extracts were obtained from Rhuschinensis Mill (RCM) leaves and used for antioxidant andantigenotoxic activity assays. IC50 values in DPPH assayswere 15.96, 18.83, 20.43, 27.93, 37.43, 46.21, and 141.84μg/mL for TPP, IPE, LLE, Vc, CE, BHT, and Trolox. Similar results were obtained using ABTS and FRAPassays. In vivo testing showed strong antioxidant activitiesthat were positively correlated with polyphenol contents. Leaf tissue contained abundant polyphenols, and more than10 phenolic compounds were detected in extracts. Quantitative results showed that quercetin-3-rhamnoside(26.4±0.76 mg/g of extract) was the most abundantingredient, followed by hyperoside (15.2±0.42 mg/g ofextract), quercetin (1.5±0.07mg/g of extract), and kaempferol(0.48±0.05 mg/g of extract). This study increases theknowledge for possible uses of forest by-products as asubstitute for gallnuts.

Synthesis and Characterization of Poly(N-arylenebenzimidazole ketone ketone)s

Yewei Xu,Jie Tang,Guanjun Chang,Fanghua Zhu,Xuan Luo,Lin Zhang 한국고분자학회 2013 Macromolecular Research Vol.21 No.6

Poly(N-arylenebenzimidazole ketone ketone)s (PNABIKKs) consisting of m- and p-phenylene linkages have been synthesized by nucleophilic aromatic substitution from bis(benzimidazolyl) derivatives containing sulfonyl,carbonyl, and ether groups with activated aromatic difluorides in sulfolane at 210 oC in the presence of anhydrous potassium carbonate. The structures of the polymers were characterized by means of Fourier tramsfom infrared (FTIR), proton nuclear magnetic resonance (1H NMR) spectroscopy, and elemental analysis, and the results were largely consistent with the proposed structure. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) measurements demonstrated that polymers had high glass transition temperatures (Tg>220 oC) and good thermal stability with high decomposition temperatures (TD>480 oC). These novel polymers also showed good solubility.

Indoor feeding combined with restricted grazing time improves body health, slaughter performance, and meat quality in Huang-huai sheep

Huang Yafeng,Zhao Mengyu,Zhang Xiaoan,Wei Huiqing,Liu Lumeng,Zhang Zi Jun,Cheng Xiao,Wang Guanjun,Ren Chunhuan 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.11

Objective: The aim of this study was to evaluate the effects of three feeding systems, i.e., indoor feeding (CON), indoor feeding with 4-h daily access to grazing artificial pasture (ITGP), and indoor feeding with 8-h daily access to grazing artificial pasture (IEGP), on the plasma antioxidant and immunological capacity, slaughter characteristics, meat quality and economic efficiency of Huang-huai lambs. Methods: Thirty-three healthy Huang-huai rams with similar body weight (approximately 5 mo of age, 28.96±1.01 kg) were assigned equally to three experimental groups. When finished fattening, six lambs from each group were collect blood samples for plasma analyses and then slaughtered to determine slaughter characteristics and obtain biceps brachii muscle for further analysis of meat quality and fatty acid profile. Results: Compared to CON group, animals submitted to ITGP and IEGP groups resulted in greater contents of serum glutathione peroxidase, immunoglobulins (IgA, IgG, and IgM), polyunsaturated fatty acids (PUFA), n-6 PUFA, and PUFA/saturated fatty acid (FA) ratio and lower palmitic /oleic acid ratio (p<0.05). Moreover, animals in ITGP group exhibited a higher (p<0.05) loin eye area, content of meat crude protein (CP), and eicosetrienoic acid compared to CON group, while slaughter performance was superior (p<0.05) to that of the IEGP group. The economic efficiency of ITGP group was 70.12% higher than that of CON group, while the IEGP group exhibited a decrease of 92.54% in economic efficiency compared to the CON group. Conclusion: Restricted grazing time combined with indoor feeding was more effective in conferring superior body health, carcass traits and economic efficiency in Huang-huai lambs, as well as higher CP content and healthier FA composition in the resulting meat.

A Fiber Spool’s Vibration Sensitivity Optimization Based on Orthogonal Experimental Design

Jing Gao,Linbo Zhang,Dongdong Jiao,Guanjun Xu,Xue Deng,Qi Zang,Honglei Yang,Ruifang Dong,Tao Liu,Shougang Zhang 한국광학회 2024 Current Optics and Photonics Vol.8 No.1

A fiber spool with ultra-low vibration sensitivity has been demonstrated for the ultra-narrowlinewidth fiber-stabilized laser by the multi-object orthogonal experimental design method, which can achieve the optimization object and analysis of influence levels without extensive computation. According to a test of 4 levels and 4 factors, an L 16 (4 4 ) orthogonal table is established to design orthogonal experiments. The vibration sensitivities along the axial and radial directions and the normalized sums of the vibration sensitivities are determined as single objects and comprehensive objects, respectively. We adopt the range analysis of object values to obtain the influence levels of the four design parameters on the single objects and the comprehensive object. The optimal parameter combinations are determined by both methods of comprehensive balance and evaluation. Based on the corresponding fractional frequency stability of ultra-narrow-linewidth fiber-stabilized lasers, we obtain the final optimal parameter combination A3B1C2D1, which can achieve the fiber spool with vibration sensitivities of 10 −12 /g magnitude. This work is the first time to use an orthogonal experimental design method to optimize the vibration sensitivities of fiber spools, providing an approach to design the fiber spool with ultra-low vibration sensitivity.

Trichoderma reesei Sch9 and Yak1 regulate vegetative growth, conidiation, and stress response and induced cellulase production

Xinxing Lv,Weixin Zhang,Guanjun Chen,Weifeng Liu 한국미생물학회 2015 The journal of microbiology Vol.53 No.4

Protein kinases are key players in controlling many basiccellular processes in almost all the organisms via mediatingsignal transduction processes. In the present study, we characterizedthe cellulolytic Trichoderma reesei orthologs ofSaccharomyces cerevisiae Sch9 and Yak1 by sequence alignmentand functional analysis. The T. reesei Trsch9Δ andTryak1Δ mutant strains displayed a decreased growth rateon different carbon sources and produced less conidia. Theabsence of these two kinases also resulted in different butabnormal polarized apical growth as well as sensitivity tovarious stresses. In addition, disruption of the genes Trsch9 orTryak1 resulted in perturbation of cell wall integrity. Interestingly,while the induced production of cellulases was slightlycompromised in the Trsch9Δ strain, the extracellular productionof cellulases was significantly improved in the absenceof Yak1. The results indicate that TrSch9 and TrYak1play an important role in filamentous growth, stress responseand induced production of cellulases in T. reesei.

pH and Redox Dual Stimuli-Responsive Injectable Hydrogels Based on Carboxymethyl Cellulose Derivatives

Yueqin Shen,Xian Li,Yawen Huang,Guanjun Chang,Ke Cao,Junxiao Yang,Renyi Zhang,Xueying Sheng,Xu Ye 한국고분자학회 2016 Macromolecular Research Vol.24 No.7

pH and redox dual stimuli-responsive injectable hydrogels were prepared by cross-linking oxidized carboxymethyl cellulose (oxi-CMC) with 3,3'-dithiobis (propionohydrazide) (DTP) via Schiff base reaction under physiological condition. The hydrogels showed good performance such as tunable gelling time, appropriate rheology properties, high swelling ratio and low degradation rate. In vitro release studies confirmed that bovine serum albumin (BSA) as a model drug exhibited a sustainable release at pH 7.4 and an accelerated release under a lower pH 5.0 and/or reducing environments. The results signified that oxi-CMC/DTP hydrogels could be an attractive candidate for drug delivery system, tissue engineering or cell scaffold materials.

Investigation of flexural strength and porosity of porous Si₃N₄ ceramics through orthogonal experimental design

Juanli Yu,Jianmei Hou,Jian Zhang,Guanjun Qiao,Zhihao Jin,Hongjie Wang 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

Porous Si3N4 ceramics by a gel casting preparation route have received considerable attention because of their excellent performance. In this paper, orthogonal experimental design L16(45) was used to investigate the preparation of porous Si3N4 ceramics by a gelcasting technique. Three variables including solid loading, monomer content and the ratio of monomers were studied. Through range analysis and variance analysis, the results suggest that the ratio of monomers has a significant influence on both the flexural strength and porosity of Si3N4 sintered bodies. For the flexural strength of a Si3N4 sintered body, the order of significance levels was as follows: the ratio of monomers, solid loading and monomer content. For the porosity of a Si3N4 sintered body, the order of significance levels was as follows: the ratio of monomers, monomer content and solid loading. The experimental results suggest also that solid loading has an optimum value where the flexural strength can achieve a maximum value. Porous Si3N4 ceramics by a gel casting preparation route have received considerable attention because of their excellent performance. In this paper, orthogonal experimental design L16(45) was used to investigate the preparation of porous Si3N4 ceramics by a gelcasting technique. Three variables including solid loading, monomer content and the ratio of monomers were studied. Through range analysis and variance analysis, the results suggest that the ratio of monomers has a significant influence on both the flexural strength and porosity of Si3N4 sintered bodies. For the flexural strength of a Si3N4 sintered body, the order of significance levels was as follows: the ratio of monomers, solid loading and monomer content. For the porosity of a Si3N4 sintered body, the order of significance levels was as follows: the ratio of monomers, monomer content and solid loading. The experimental results suggest also that solid loading has an optimum value where the flexural strength can achieve a maximum value.

Polymer-Assisted Pressure Sensor with Piezoresistive Suspended Graphene and Its Temperature Characteristics

Xin Lin,Ying Liu,Yong Zhang,Peng Yang,Xianzhe Cheng,Jing Qiu,Guanjun Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

A polymer-assisted pressure sensor with piezoresistive suspended graphene is proposed and fabricated with high yield. Our sensor exhibits a good pressure response comparable to that of commercial sensors. The sensitivity is estimated to be 2.87 x 10 -5 kPa -1, higher than that of similar Si-based pressure sensors. The influence of the temperature on the sensor performance is systematically analyzed. An inverse temperature response is observed, and a nonnegligible temperature effect on the sensor resistance is demonstrated. Considering the temperature-induced cavity pressure change, a new temperature–resistance model is built to explain the nonlinearity of the sensor response to the temperature variation. Experiments under different test voltages show the influence of the current thermal effect, which is similar to that of temperature and nonnegligible for high-precision pressure sensors. Our new sensor holds great potential for practical application, and the findings on the temperature characteristics open up a route to further improve the sensor performance.

Amplification of transglutaminase 2 enhances tumor-promoting inflammation in gastric cancers

Cho Sung-Yup,오유미,Jeong Eui Man,박상희,Dakeun Lee,Xiaorui Wang,Qiqi Zeng,Hongyu Qin,Fang Hu,Hui Gong,Xi Liu,Guanjun Zhang,나득채,이지은,채지수,서윤석,공성호,Hyuk-Joon Lee,Jong-Il Kim,박한수,Chengsheng Zhang,양한광,Charles Lee 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Tumor-promoting inflammation is a hallmark of cancer and is highly associated with tumor progression, angiogenesis, and metastasis. Tumor-associated macrophages (TAMs) are major drivers of tumor-promoting inflammation, but due to the complexity of the tumor microenvironment, the detailed regulatory mechanisms are still under investigation. Here, we investigated a novel role for transglutaminase 2 (TGM2) in the development of tumor-promoting inflammation and recruitment of TAMs to gastric cancer (GC) tissues. When estimated by array comparative genomic hybridization and droplet digital PCR, the copy numbers of the TGM2 gene were amplified in 13.6% (14/103) of GC patients and positively associated with TGM2 expression. Gene set enrichment analysis of expression microarray data for GC samples with high or low TGM2 expression showed that increased TGM2 expression was associated with tumor-promoting inflammation in GC. In addition, the expression of TGM2 was correlated with the expression of markers for macrophages, neutrophils, blood vessels, and lymphatic vessels. Overexpression of TGM2 in GC cells augmented the IL-1β-induced secretion of macrophage-recruiting chemokines and NF-κB activation. TGM2 protein levels were associated with the expression levels of the macrophage marker CD163 in human GC tissue samples. Moreover, GC patients with high expression of TGM2 had a worse prognosis than those with low expression of TGM2. These results suggest TGM2 as a novel regulator of the tumor microenvironment of GC and provide a promising target for constraining tumor-promoting inflammation.