Highly Sensitive and Selective PbTiO₃ Gas Sensors with Negligible Humidity Interference in Ambient Atmosphere

Ma, Xing-Hua,Li, Hua-Yao,Kweon, Sang-Hyo,Jeong, Seong-Yong,Lee, Jong-Heun,Nahm, Sahn American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.5

<P>Three PbTiO<SUB>3</SUB> nanostructures were synthesized using a one-step hydrothermal reaction with different TiO<SUB>2</SUB> powders as Ti sources, and their gas-sensing properties were investigated. The sensor comprising PbTiO<SUB>3</SUB> nanoplates (NPs) exhibited a high response (resistance ratio = 80.4) to 5 ppm ethanol at 300 °C and could detect trace concentrations of ethanol down to 100 ppb. Moreover, the sensor showed high ethanol selectivity and nearly the same sensing characteristics despite the wide range of humidity variation from 20 to 80% RH. The mechanism for humidity-independent gas sensing was elucidated using diffuse reflectance infrared Fourier transform spectra. PbTiO<SUB>3</SUB> NPs are new and promising sensing materials that can be used for detecting ethanol in a highly sensitive and selective manner with negligible interference from ambient humidity.</P> [FIG OMISSION]</BR>

Comparative Study on Characterization of Recombinant B Subunit of E. coli Heat-Labile Enterotoxin (rLTB) Prepared from E. coli and P. pastoris

( Xing Yuna Ma ),( Bi Yao ),( Wen Yun Zheng ),( Lin Feng Li ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.3

Reversed Janus Micro/Nanomotors with Internal Chemical Engine

Ma, Xing,Jang, Seungwook,Popescu, Mihail N.,Uspal, William E.,Miguel-Ló,pez, Albert,Hahn, Kersten,Kim, Dong-Pyo,Sá,nchez, Samuel American Chemical Society 2016 ACS NANO Vol.10 No.9

<P/><P>Self-motile Janus colloids are important for enabling a wide variety of microtechnology applications as well as for improving our understanding of the mechanisms of motion of artificial micro- and nanoswimmers. We present here micro/nanomotors which possess a reversed Janus structure of an internal catalytic “chemical engine”. The catalytic material (here platinum (Pt)) is embedded within the interior of the mesoporous silica (mSiO<SUB>2</SUB>)-based hollow particles and triggers the decomposition of H<SUB>2</SUB>O<SUB>2</SUB> when suspended in an aqueous peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) solution. The pores/gaps at the noncatalytic (Pt) hemisphere allow the exchange of chemical species in solution between the exterior and the interior of the particle. By varying the diameter of the particles, we observed size-dependent motile behavior in the form of enhanced diffusion for 500 nm particles, and self-phoretic motion, toward the nonmetallic part, for 1.5 and 3 μm ones. The direction of motion was rationalized by a theoretical model based on self-phoresis. For the 3 μm particles, a change in the morphology of the porous part is observed, which is accompanied by a change in the mechanism of propulsion <I>via</I> bubble nucleation and ejection as well as a change in the direction of motion.</P>

Low-temperature sintering and microwave dielectric properties of B₂O₃-added ZnO-deficient Zn₂GeO₄ ceramics for advanced substrate application

Ma, Xing-Hua,Kweon, Sang-Hyo,Im, Mir,Nahm, Sahn Elsevier 2018 Journal of the European Ceramic Society Vol.38 No.14

<P><B>Abstract</B></P> <P>ZnO-deficient Zn<SUB>2-</SUB> <I> <SUB>x</SUB> </I>GeO<SUB>4-</SUB> <I> <SUB>x</SUB> </I> ceramics with 0.05 ≤ <I>x</I> ≤ 0.15 were synthesized because a ZnO secondary phase is formed in the stoichiometric Zn<SUB>2</SUB>GeO<SUB>4</SUB> ceramics synthesized using micrometer-sized ZnO and GeO<SUB>2</SUB> powders. The Zn<SUB>1.9</SUB>GeO<SUB>3.9</SUB> ceramic sintered at 1000 °C showed a homogeneous Zn<SUB>2</SUB>GeO<SUB>4</SUB> phase with good microwave dielectric properties: <I>ε<SUB>r</SUB> </I> of 6.8, <I>Q</I> × <I>f</I> of 49,000 GHz, and <I>τ<SUB>f</SUB> </I> of −16.7 ppm/°C. However, its sintering temperature was still too high for it to be used as an advanced substrate for low-temperature co-fired ceramic devices. Therefore, various amounts of B<SUB>2</SUB>O<SUB>3</SUB> were added to the Zn<SUB>1.9</SUB>GeO<SUB>3.9</SUB> ceramics to reduce their sintering temperature. Owing to the formation of a B<SUB>2</SUB>O<SUB>3</SUB>-GeO<SUB>2</SUB> liquid phase, these ceramics were well sintered at low temperatures between 925 °C and 950 °C. In particular, 15 mol% B<SUB>2</SUB>O<SUB>3</SUB>-added Zn<SUB>1.9</SUB>GeO<SUB>3.9</SUB> ceramic sintered at 950 °C showed promising microwave dielectric properties for advanced substrates without the reaction with an Ag electrode: <I>ε<SUB>r</SUB> </I> = 6.9, <I>Q</I> × <I>f</I> = 79,000 GHz, and <I>τ<SUB>f</SUB> </I> = −15 ppm/°C.</P>

Hepatitis B Virus DNA Negativity Acts as a Favorable Prognostic Factor in Hepatocellular Carcinoma Patients

Li, Xing,Zhong, Xiang,Chen, Zhan-Hong,Xing, Yan-Fang,Wu, Dong-Hao,Chen, Jie,Ma, Xiao-Kun,Lin, Qu,Wen, Jing-Yun,Wei, Li,Wang, Tian-Tian,Ruan, Dan-Yun,Lin, Ze-Xiao,Wu, Xiang-Yuan,Dong, Min Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: This retrospective study was aimed to investigate the efficacy of prophylactic agents in hepatocellular carcinoma (HCC) patients receiving TACE and compare the difference between lamivudine and entecavir. Materials and Methods: A consecutive series of 203 HBV-related HCC patients receiving TACE were analyzed including 91 patients given prophylactic agents. Virologic events, defined as an increase in serum HBV DNA level to more than 1 log10 IU/ml higher than the nadir level, hepatitis flares due to HBV reactivation and progression free survival (PFS) were the main endpoints. Results: Some 48 (69.6%) reached virologic response. Prophylaxis significantly reduced virologic events (8.8% vs 58.0%, p=0.000) and hepatitis flares (1.1% vs 13.4%, p=0.001). Patients presenting undetectable HBV DNA levels displayed a significantly improved PFS as compared to those who never achieved undetectable HBV DNA. Prophylaxis and e-antigen positivity were the only significant variables associated with virologic events. In addition, prophylaxis was the only independent protective factor for hepatitis flares. Liver cirrhosis, more cycles of TACE, HBV DNA negativity, a lower Cancer of the Liver Italian Program score, non-metastasis and no hepatitis flares were protective factors for PFS. Prophylactic lamivudine demonstrated similar efficacy as entecavir. Conclusions: Prophylactic agents are efficacious for prevention of HBV reactivation in HCC patients receiving TACE. Achievement of undetectable HBV DNA levels displayed a significant capability in improving PFS. Moreover, persistent tumor residual lesions, positive HBV DNA and hepatitis B flares might be causes of tumor progression in these patients.

Lignosulfonate-Assisted Hydrothermal Synthesis of Mesoporous MnFe2O4 and Fe3O4 for Pb(II) Removal

Yuan Ma,SHENGTAO XING,YINSU WU,Yuanzhe Gao,ZICHUAN MA 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.3

The development of efficient magnetic adsorbents is highly desirable for water treatment. In this work, MnFe2O4 and Fe3O4 were prepared by a lignosulfonate-assisted hydrothermal method. The structure, surface property and adsorption capacity of the products were investigated. The obtained products have a small amount of carbonaceous materials, mesoporous structure and narrow pore size distribution. In comparison with the samples prepared without lignosulfonate, they have more surface hydroxyl groups and highly negatively charged surface in aqueous solution, which favor the adsorption of cations. Fe3O4 and especially MnFe2O4 exhibited high adsorption capacity towards Pb(II). The maximal removal efficiency of Pb(II) (50 mg L -1) on MnFe2O4 was 100% at pH 6.2. The results demonstrate that this method is promising for the synthesis of magnetic adsorbent.

Identification and Characterization of Protein Encoded by orf382 as L-Threonine Dehydrogenase

( Fei Ma ),( Tian Wen Wang ),( Xing Yuan Ma ),( Ping Wang ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.6

In the genome annotation of Escherichia coli MG1655, the orf382 (1,149 bp) is designated as a gene encoding an alcohol dehydrogenase that may be Fe-dependent. In this study, the gene was amplified from the genome by PCR and overexpressed in Escherichia coli BL21(DE3). The recombinant 6×His-tag protein was then purified and characterized. In an enzymatic assay using different hydroxyl-containing substrates (n-butanol, L-threonine, ethanol, isopropanol, glucose, glycerol, L-serine, lactic acid, citric acid, methanol, or D-threonine), the enzyme showed the highest activity on L-threonine. Characterization of the mutant constructed using gene knockout of the orf382 also implied the function of the enzyme in the metabolism of L-threonine into glycine. Considering the presence of tested substrates in living E. coli cel ls and previous literature, we believed that the suitable nomenclature for the enzyme should be an L-threonine dehydrogenase (LTDH). When using L-threonine as the substrate, the enzyme exhibited the best catalytic performance at 39°C and pH 9.8 with NAD+ as the cofactor. The determination of the Km values towards L-threonine (Km = 11.29 μM), ethanol (222.5 μM), and n-butanol (8.02 μM) also confirmed the enzyme as an LTDH. Furthermore, the LTDH was shown to be an ion-containing protein based on inductively coupled plasma-atomic emission spectrometry with an isoelectronic point of pH 5.4. Moreover, a circular dichroism analysis revealed that the metal ion was structurally and enzymatically essential, as its deprivation remarkably changed the α-helix percentage (from 12.6% to 6.3%).

Efficacy of Prophylactic Entecavir for Hepatitis B Virus-Related Hepatocellular Carcinoma Receiving Transcatheter Arterial Chemoembolization

Li, Xing,Zhong, Xiang,Chen, Zhan-Hong,Wang, Tian-Tian,Ma, Xiao-Kun,Xing, Yan-Fang,Wu, Dong-Hao,Dong, Min,Chen, Jie,Ruan, Dan-Yun,Lin, Ze-Xiao,Wen, Jing-Yun,Wei, Li,Wu, Xiang-Yuan,Lin, Qu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.18

Background and Aims: Hepatitis B virus (HBV) reactivation was reported to be induced by transcatheter arterial chemoembolization (TACE) in HBV-related hepatocellular carcinonma (HCC) patients with a high incidence. The effective strategy to reduce hepatitis flares due to HBV reactivation in this specific group of patients was limited to lamivudine. This retrospective study was aimed to investigate the efficacy of prophylactic entecavir in HCC patients receiving TACE. Methods: A consecutive series of 191 HBV-related HCC patients receiving TACE were analyzed including 44 patients received prophylactic entecavir. Virologic events, defined as an increase in serum HBV DNA level to more than 1 log10 copies/ml higher than nadir the level, and hepatitis flares due to HBV reactivation were the main endpoints. Results: Patients with or without prophylactic were similar in host factors and the majorities of characteristics regarding to tumor factors, HBV status, liver function and LMR. Notably, cycles of TACE were parallel between the groups. Ten (22.7%) patients receiving prophylactic entecavir reached virologic response. The patients receiving prophylactic entecavir presented significantly reduced virologic events (6.8% vs 54.4%, p=0.000) and hepatitis flares due to HBV reactivation (0.0% vs 11.6%, p=0.039) compared with patients without prophylaxis. Kaplan-Meier analysis illustrated that the patients in the entecavir group presented significantly improved virologic events free survival (p=0.000) and hepatitis flare free survival (p=0.017). Female and Eastern Cooperative Oncology Group (ECOG) performance status 2 was the only significant predictors for virological events in patients without prophylactic antiviral. Rescue antiviral therapy did not reduce the incidence of hepatitis flares due to HBV reactivation. Conclusion: Prophylactic entecavir presented promising efficacy in HBV-related cancer patients receiving TACE. Lower performance status and female gender might be the predictors for HBV reactivation in these patients.

Staged Improvement in Awareness of Disease for Elderly Cancer Patients in Southern China

Li, Xing,Dong, Min,Wen, Jing-Yun,Wei, Li,Ma, Xiao-Kun,Xing, Yan-Fang,Deng, Yun,Chen, Zhan-Hong,Chen, Jie,Ruan, Dan-Yun,Lin, Ze-Xiao,Wang, Tian-Tian,Wu, Dong-Hao,Liu, Xu,Hu, Hai-Tao,Lin, Jia-Yu,Li, Zhu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: In mainland China, awareness of disease of elderly cancer patients largely relies on the patients' families. We developed a staged procedure to improve their awareness of disease. Materials and Methods: Participants were 224 elderly cancer patients from 9 leading hospitals across Southern China. A questionnaire was given to the oncologists in charge of each patient to evaluate the interaction between family and patients, patient awareness of their disease and participation in medical decision-making. After first cycles of treatment, increased information of disease was given to patients with cooperation of the family. Then patient awareness of their disease and participation in medical decision-making was documented. Results: Among the 224 cancer elderly patients, 26 (11.6%) made decisions by themselves and 125 (55.8%) delegated their rights of decision-making to their family. Subordinate family members tended to play a passive role in decision-making significantly. Patients participating more in medical decision-making tended to know more about their disease. However, in contrast to the awareness of disease, patient awareness of violation of medical recommendations was reversely associated with their participation in medical decision-making. Improvement in awareness of diagnosis, stages and prognosis was achieved in about 20% elderly cancer patients. About 5% participated more actively in medical decision-making. Conclusions: Chinese elderly cancer patient awareness of disease and participation in medical decision-making is limited and relies on their family status. The staged procedure we developed to improve patient awareness of disease proved effective.

Two type III polyketide synthases from Polygonum cuspidatum: gene structure, evolutionary route and metabolites

Lan-Qing Ma,Yan-Wu Guo,Hui-Li Guo,Xing Li,Li-Li Huang,Bo-Ning Zhang,Xiao-Bin Pang,Ben-Ye Liu,Hong Wang 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.3

In our recent work (Ma et al., in Planta229(3):457–469, 2009a and 229(4):1077–1086, 2009b),two three-intron type III PKS genes, PcPKS1 and PcPKS2,were isolated from Polygonum cuspidatum Sieb. et Zucc. Phylogenetic and functional analyses revealed PcPKS1 is athree-intron chalcone synthase (CHS) gene, and PcPKS2 isfound to be a three-intron benzalacetone synthase (BAS)gene. The regular CHS encoded by a single intron genehave not been isolated and characterized from P. cuspidatum. In this work a further CHS with one intron (PcPKS3)and a stilbene synthase (STS) gene with three-intron(PcPKS5) were isolated and characterized by functionaland phylogenetic analyses. In comparison with PcPKS1, abifunctional enzyme with both CHS and BAS activity, theenzymatic product of recombinant PcPKS3 was naringenin,bis-noryangonin (BNY) and 4-coumaroyltriacetic acidlactone (CTAL) occurred as side products. The PcPKS5synthesized resveratrol and a trace amount of naringeninfrom p-coumaroyl-CoA. To our knowledge, PcPKS5 is thefirst reported three-intron STS gene in flowering plants. Inthis work, we speculated that this involved a possibleevolutionary route of plant-specific type III PKS superfamilyin P. cuspidatum.