Effect of La2O3 on the microstructure and electrical properties of ZnO linear resistors

Yajun Fu,Jiajia Lu,Jin Wang,Liangfeng Li 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.4

ZnO-MgO-Al2O3-TiO2-Y2O3 linear resistors with different amount of La2O3 were successfully prepared by the conventionalsolid-state sintering method. The crystalline phase composition, microstructure, and electrical properties of La2O3 doped ZnOlinear resistors were investigated. The results show that La2O3 influences the lattice of ZnO and generates La-rich phase atthe grain boundaries, which improves the dense density of ZnO linear resistors. The addition of La2O3 further affect theelectrical properties of ZnO linear resistors, such as the temperature stability. The sample with 0.5 wt.% La2O3 show excellentelectrical performance with an resistance-temperature coefficient of 0.21×10-3/°C and an nonlinear coefficient of 1.05.

Effects of Sintering Process on Microstructure and Microwave Dielectric Properties of Ba(Co1/3Nb2/3)O3 Ceramics

Zhefei Wang,Jiajia Wu,Lixi Wang,Zhenxiao Fu,Qitu Zhang 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.6

Ba(Co1/3Nb2/3)O3 (BCN) ceramics were prepared using a conventional solid-state route. Effects of sintering on microstructure and microwave dielectric properties of Ba(Co1/3Nb2/3)O3 ceramics were systematically investigated. Appropriate sintering temperature could restrain the evaporation of CoO and the formation of Nb-rich phase. The dielectric constants and temperature coefficients of resonant frequency changed slightly with the variation in sintering temperatures. The high Q× f value with prolonged sintering time was related to the improvement of 1 : 2 ordered arrangement in the B site, rather than the compactness of ceramics. Excellent microwave dielectric properties (εr=32.6, Q×f =86857 GHz, τf=−14 ppm/°C) were obtained in the Ba(Co1/3Nb2/3)O3 ceramics sintered at 1380°C for 12 h.

Degradation behavior of deep UV-LEDs studied by electro-optical methods and transmission electron microscopy

Huixin Xiu,Yang Zhang,Jiajia Fu,Zhanhong Ma,Lixia Zhao,Jijun Feng 한국물리학회 2019 Current Applied Physics Vol.19 No.1

Degradation mechanism of 265-nm deep ultraviolet light emitting diodes (UV-LEDs) has been investigated by means of electroluminescence, current-voltage measurement, capacitance-voltage measurement, and transmission electron microscopy (TEM) equipped with energy dispersive X-ray spectrometer (EDAX). It is revealed that a major degradation mode of UV-LEDs may be the leakage current induced optical degradation. The current pathway is demonstrated by TEM with EDAX, indicating that the contact metals can partially interact with ptype materials, which accelerate the degradation of LEDs. The presented results can help to understand the degradation mechanisms and improve the reliability of deep UV-LEDs.

A Campus Community-based Mobility Model for Routing in Opportunistic Networks

( Daru Pan ),( Min Fu ),( Jiajia Sun ),( Xin Zou ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.3

Mobility models are invaluable for determining the performance of routing protocols in opportunistic networks. The movement of nodes has a significant influence on the topological structure and data transmission in networks. In this paper, we propose a new mobility model called the campus-based community mobility model (CBCNM) that closely reflects the daily life pattern of students on a real campus. Consequent on a discovery that the pause time of nodes in their community follows a power law distribution, instead of a classical exponential distribution, we abstract the semi-Markov model from the movement of the campus nodes and analyze its rationality. Then, using the semi-Markov algorithm to switch the movement of the nodes between communities, we infer the steady-state probability of node distribution at random time points. We verified the proposed CBCNM via numerical simulations and compared all the parameters with real data in several aspects, including the nodes` contact and inter-contact times. The results obtained indicate that the CBCNM is highly adaptive to an actual campus scenario. Further, the model is shown to have better data transmission network performance than conventional models under various routing strategies.

The mitochondrial unfolded protein response (UPRmt) protects against osteoarthritis

Zhou Zhibin,Lu Jiajia,Yang Mei,Cai Jiao,Fu Qiang,Ma Jun,Zhu Lei 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

The mitochondrial unfolded protein response (UPRmt) is a mitochondrial-to-nuclear signaling pathway that is activated to maintain mitochondrial function when there is an accumulation of misfolded proteins within mitochondria. Mitochondrial function is essential for chondrocyte homeostasis, and mitochondrial dysfunction is a characteristic of osteoarthritis (OA). However, the role of the UPRmt in OA remains unclear. In the present study, the level of the UPRmt was examined in primary mouse chondrocytes subjected to different stresses and in the articular cartilage of OA model mice and OA patients. The relationship between UPRmt activation and OA progression was studied. The UPRmt was induced in primary mouse chondrocytes subjected to diverse stresses and in the cartilage of OA mice. Enhancement of the UPRmt with nicotinamide riboside (NR) significantly improved mitochondrial function, reduced chondrocyte death, attenuated OA pain, and ameliorated OA progression, and the protective effects decreased significantly in chondrocyte-specific Atf5 knockout (ATF5f/fCol2a1-CreERT2) mice. UPRmt induction was also identified in the articular cartilage of OA patients and was associated with reduced chondrocyte death, less severe hip pain, and lower levels of inflammation in synovial fluid. These findings identify the induction of the UPRmt in primary mouse chondrocytes exposed to pathological stresses and in the articular cartilage of OA model mice and OA patients. Enhancement of the UPRmt ameliorates OA progression, suggesting that the UPRmt exerts a protective effect against OA and may be a potential diagnostic and therapeutic strategy for OA.

Eco-friendly and Durable Antibacterial Cotton Fabrics Prepared with Polysulfopropylbetaine

Li Zhou,Hongbo Wang,Jinmei Du,Jiajia Fu,Wencong Wang 한국섬유공학회 2018 Fibers and polymers Vol.19 No.6

A novel antibacterial agent polysulfopropylbetaine (PSPB) bearing carboxyl groups was synthesized and its application on cotton fabric to provide durable antibacterial property was also presented. The successful synthesis of PSPB and its immobilization onto the cotton fabric surface were verified by a series of tests including FTIR, 1H NMR, XPS and SEM. Viable cell counting method was employed to investigate antibacterial properties of the finished cotton fabrics. It was found that the cotton fabrics treated with PSPB were endowed with desirable antibacterial activity against both gram-negative bacteria Esherichia coli (E.coli, AATCC 6538) and gram-positive bacteria Staphylococcus aureus (S.aureus, AATCC 25922), with the bacterisotatic rates of 99.69 % and 99.95 %, respectively. Notably, the bacterial reduction rates still maintained over 90 % against both bacteria even after 50 consecutive laundering cycles. Moreover, tests concerning the hydrophilicity, air permeability, water vapor transmission, mechanical properties as well as thermal properties were carried out systematically. The experimental results indicated the hydrophilic performance, air permeability and moisture penetrability of the cotton fabrics finished with PSPB were improved greatly in spite of a slight reduction in thermal performance and little obvious influence on mechanical performance. The antibacterial cotton fabric has the potential to be applied in sportswear, underwear, household textiles, medical fields and much more.

A Novel Xylanase from Streptomyces sp. FA1: Purification, Characterization, Identification, and Heterologous Expression

Jie He,Lingqia Su,Xiaojun Sun,Jiajia Fu,Jian Chen,Jing Wu 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.1

A xylanase (XynA) was purified from the culturemedium of Streptomyces sp. FA1, which was previouslyisolated from a bamboo retting system. XynA had amolecular mass of 43 kDa, displayed maximal activity atpH 5.5, retained 41% of its maximal activity at pH 11.0,and was stable over a wide pH range (3.0 ~ 11.0). PurifiedXynA was subjected to peptide mass fingerprinting, whichled to the cloning of the xynA gene. The xynA gene, whichencodes a mature protein of 436 amino acids, washeterologously expressed in E. coli BL21(DE3). The activityin the culture medium could reach 213.5 U/mL, which was11.2-fold higher than that produced by Streptomyces sp. FA1. BLAST searching revealed that full-length XynAshares less than 90% identity with most of its homologues,whereas amino acids 48-436 of the enzyme share 97%identity with an open reading frame encoding a putativefull-length mature xylanase from Streptomyces tendae. Thetruncated xynA gene, xynA48-436, was cloned and expressedin E. coli, however, no xylanase activity could be detectedin the culture medium. Based on these results, it is suggestedthat XynA is a new member of glycoside hydrolasesfamily10 with exceptional catalytic efficiency at alkalinepH.

Characterization of Ribose-5-Phosphate Isomerase B from Newly Isolated Strain Ochrobactrum sp. CSL1 Producing L-Rhamnulose from L-Rhamnose

( Min Shen ),( Xin Ju ),( Xinqi Xu ),( Xuemei Yao ),( Liangzhi Li ),( Jiajia Chen ),( Cuiying Hu ),( Jiaolong Fu ),( Lishi Yan ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.7

In this study, we attempted to find new and efficient microbial enzymes for producing rare sugars. A ribose-5-phosphate isomerase B (OsRpiB) was cloned, overexpressed, and preliminarily purified successfully from a newly screened Ochrobactrum sp. CSL1, which could catalyze the isomerization reaction of rare sugars. A study of its substrate specificity showed that the cloned isomerase (OsRpiB) could effectively catalyze the conversion of L-rhamnose to L-rhamnulose, which was unconventional for RpiB. The optimal reaction conditions (50oC, pH 8.0, and 1 mM Ca²⁺) were obtained to maximize the potential of OsRpiB in preparing L-rhamnulose. The catalytic properties of OsRpiB, including K_m, K_cat, and catalytic efficiency (K_cat/K_m), were determined as 43.47 mM, 129.4 sec^-1, and 2.98 mM/sec. The highest conversion rate of L-rhamnose under the optimized conditions by OsRpiB could reach 26% after 4.5 h. To the best of our knowledge, this is the first successful attempt of the novel biotransformation of L-rhamnose to L-rhamnulose by OsRpiB biocatalysis.

Clinical Features and Differences of Miller Fisher Syndrome in Southern China: Retrospective Analysis of 72 Patients in 13 Provinces of Southern China

Hang Yu,Man Ding,Qian Cao,Rumeng Zhou,Jiajia Yao,Rong Fu,Yue Liu,Zheman Xiao,Zuneng Lu 대한신경과학회 2023 Journal of Clinical Neurology Vol.19 No.6

Background and Purpose We aimed to determine the clinical features of Miller Fisher syndrome (MFS) in southern China and compare them with those presenting in other countries. Methods We collected the medical records of patients diagnosed with MFS during 2013–2016. We analyzed the age, sex, onset season, precursor events, clinical symptoms and signs, findings of nerve conduction studies (NCS), cerebrospinal fluid (CSF), therapeutic remedies, nadir time, and length of hospital stay of patients with MFS in southern China. We concurrently compared the differences between urban and rural areas and between patients with incomplete ophthalmoplegia (IO) and complete ophthalmoplegia (CO). Results The study enrolled 72 patients: 36 from rural areas and 36 from urban areas, and 50 males and 22 females. The mean age at onset was 47.72 years, and 30 (41.7%) and 21 (29.2%) patients developed MFS in spring and winter, respectively. The typical triad of ophthalmoplegia, ataxia, and areflexia was observed in 50 (69.4%) patients. A history of upper respiratory tract infection 1 week before onset was found in 52.8% of the patients, while 5.6% experienced gastrointestinal infections and 48 (73.8%) exhibited albuminocytological dissociation in the CSF study. Only 26 (36.1%) patients presented abnormalities in NCS. Moreover, restricted outward eyeball movement presented in 83.5% of the patients with classic MFS and acute ophthalmoplegia, and bilateral symmetrical ophthalmoplegia presented in 64.2%. With the exception of the higher proportion of NCS abnormalities in urban areas (47.2% vs. 25.0%), urban and rural differences were insignificant regarding sex ratio, age at onset, high-incidence season, precursor events, disease characteristics, and albuminocytological dissociation in the CSF. Furthermore, patients with CO were older than those with IO (64.53±7.69 vs. 43.19±14.40 years [mean±standard deviation], p<0.001). Conclusions The patients with MFS were mostly male and middle-aged, and most presented in winter and (especially) spring. More than half of the patients had clear precursor events, most of which were classic MFS with the typical triad. More than 70% of the patients presented albuminocytological dissociation in the CSF. NCS abnormalities were uncommon in MFS. The age at onset was lower in patients with IO than in patients with CO; bilateral symmetrical extraocular muscle paralysis was the most common symptom, and the external rectus was the most frequently involved muscle.

Efficacy and Safety of Pulse Magnetic Therapy System in Insomnia Disorder: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

Liao Jiwu,Wang Sisi,Zhou Borong,Liang Wei,Ma Ping,Lin Min,Lin Weisen,Li Congrui,Zhang Xiaotao,Li Hongyao,Cui Yin,Hu Jiajia,Qin Yuanyi,Deng Yanhua,Fu Aibing,Zhu Tianhua,Zhang Shanlian,Qu Yunhong,Xing L 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.6

Objective This study’s objective is to assess the efficacy and safety of Pulsed Magnetic Therapy System (PMTS) in improving insomnia disorder.Methods Participants with insomnia disorder were randomly assigned to receive either PMTS or sham treatment for four weeks (n= 153; PMTS: 76, sham: 77). Primary outcomes are the Insomnia Severity Index (ISI) scores at week 0 (baseline), 1, 2, 3, 4 (treatment), and 5 (follow-up). Secondary outcomes are the Pittsburgh Sleep Quality Index at baseline and week 4, and weekly sleep diary-derived values for sleep latency, sleep efficiency, real sleep time, waking after sleep onset, and sleep duration.Results The ISI scores of the PMTS group and the sham group were 7.13±0.50, 11.07±0.51 at week 4, respectively. There was a significant group×time interaction for ISI (F3.214, 485.271=24.25, p<0.001, ηp 2=0.138). Only the PMTS group experienced continuous improvement throughout the study; in contrast, the sham group only experienced a modest improvement after the first week of therapy. At the end of the treatment and one week after it, the response of the PMTS group were 69.7% (95% confidence interval [CI]: 58.6%–79.0%), 75.0% (95% CI: 64.1%–83.4%), respectively, which were higher than the response of the sham group (p<0.001). For each of the secondary outcomes, similar group×time interactions were discovered. The effects of the treatment persisted for at least a week.Conclusion PMTS is safe and effective in improving insomnia disorders.