Spectral Research on an AlGaAs Epitaxial Material for a Terahertz Quantum-cascade Laser

Zhi-Yong Tan,Jun-Cheng Cao 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.8

The spectral properties of a series of AlGaAs epitaxial films were studied by using a Fourier transform infrared spectrometer with an 80-degree grazing incidence reflection unit. The AlAslike transversal optical phonon was obviously observed in the spectra, but the longitudinal optical phonon was obscured in the transmission spectra. The variation curves for the transversal optical phonon energy were acquired from the two kinds of spectra and were compared with each other and with the early results. A comparison of the results show that the grazing incidence reflection spectrum is better in reflecting the AlAs-like phonon energy of an AlGaAs epitaxial film and could be a supplementary means in the characterization of the material for a terahertz quantum-cascade laser.

The MALATANG Survey: The <i>L</i>_GAS-<i>L</i>_IR Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN <i>J</i> = 4 → 3 and HCO⁺<i>J</i> = 4 → 3

Tan, Qing-Hua,Gao, Yu,Zhang, Zhi-Yu,Greve, Thomas R.,Jiang, Xue-Jian,Wilson, Christine D.,Yang, Chen-Tao,Bemis, Ashley,Chung, Aeree,Matsushita, Satoki,Shi, Yong,Ao, Yi-Ping,Brinks, Elias,Currie, Malco American Astronomical Society 2018 The Astrophysical journal Vol.860 No.2

<P>We present HCN J = 4 -> 3 and HCO+ J = 4 -> 3 maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2' x 2' region at 14 '' (FWHM) resolution (corresponding to linear scales of similar to 0.2-1.0 kpc). The L-IR-L'(dense) relation, where the dense gas is traced by the HCN J = 4 -> 3 and the HCO+ J = 4 -> 3 emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, L-IR/L'(dense), shows systematic variations with L-IR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between L-IR/L'(dense) ratio and the warm-dust temperature gauged by the 70 mu m/100 mu m flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO+ (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFEdense), appear to be nearly independent of the dense gas fraction (f(dense)) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with f(dense) when combining our data with those on local (ultra) luminous infrared galaxies and high-z quasars. The mean L'(HCN(4-3))/L'(HCO+(4-3)) line ratio measured for the six targeted galaxies is 0.9 +/- 0.6. No significant correlation is found for the L'(HCN(4-3)) L'(HCO+(4-3)) ratio with the star formation rate as traced by L-IR, nor with the warm-dust temperature, for the different populations of galaxies.</P>

Toward Full Spectrum Speciation of Silver Nanoparticles and Ionic Silver by On-Line Coupling of Hollow Fiber Flow Field-Flow Fractionation and Minicolumn Concentration with Multiple Detectors

Tan, Zhi-Qiang,Liu, Jing-Fu,Guo, Xiao-Ru,Yin, Yong-Guang,Byeon, Seul Kee,Moon, Myeong Hee,Jiang, Gui-Bin American Chemical Society 2015 ANALYTICAL CHEMISTRY - Vol.87 No.16

<P>The intertransformation of silver nanoparticles (AgNPs) and ionic silver (Ag(I)) in the environment determines their transport, uptake, and toxicity, demanding methods to simultaneously separate and quantify AgNPs and Ag(I). For the first time, hollow fiber flow field-flow fractionation (HF5) and minicolumn concentration were on-line coupled together with multiple detectors (including UV–vis spectrometry, dynamic light scattering, and inductively coupled plasma mass spectrometry) for full spectrum separation, characterization, and quantification of various Ag(I) species (<I>i.e</I>., free Ag(I), weak and strong Ag(I) complexes) and differently sized AgNPs. While HF5 was employed for filtration and fractionation of AgNPs (>2 nm), the minicolumn packed with Amberlite IR120 resin functioned to trap free Ag(I) or weak Ag(I) complexes coming from the radial flow of HF5 together with the strong Ag(I) complexes and tiny AgNPs (<2 nm), which were further discriminated in a second run of focusing by oxidizing >90% of tiny AgNPs to free Ag(I) and trapped in the minicolumn. The excellent performance was verified by the good agreement of the characterization results of AgNPs determined by this method with that by transmission electron microscopy, and the satisfactory recoveries (70.7–108%) for seven Ag species, including Ag(I), the adduct of Ag(I) and cysteine, and five AgNPs with nominal diameters of 1.4 nm, 10 nm, 20 nm, 40 nm, and 60 nm in surface water samples.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2015/ancham.2015.87.issue-16/acs.analchem.5b01827/production/images/medium/ac-2015-01827q_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac5b01827'>ACS Electronic Supporting Info</A></P>

Length of hospital stay among oral and maxillofacial patients: a retrospective study

Fo Yew Tan,Kalpana Selvaraju,Harshinie Audimulam,Zhi Chuan Yong,Tassha Hilda Adnan,Sathesh Balasundram 대한구강악안면외과학회 2021 대한구강악안면외과학회지 Vol.47 No.1

Objectives: Many conditions of the oral and maxillofacial region require hospitalization and in-patient care. The average length of stay (LOS) of these patients varies and is usually affected by multiple confounding variables. However, even with an increasing number of hospital admissions, published evidence on the factors that affect the LOS of oral and maxillofacial patients is lacking. Therefore, this study assessed the LOS of in-patients at the oral and maxillofacial surgery department of a government-funded, multi-specialty hospital in Malaysia, based on their reasons for admission and other factors. Materials and Methods: Our samples were collected retrospectively over a 5-year period and included patients with maxillofacial infections, posttrauma stabilization, facial bone fracture surgery, benign and malignant lesion surgery, dentoalveolar surgery, and other maxillofacial surgeries as reasons for admission. Factors potentially affecting LOS were also recorded, and their significance was determined using multiple logistic regression analyses. A P-value of less than 0.05 was considered to be statistically significant. Results: A total of 1,380 patients were included in this study. Most (84.5%) of our in-patients were of Malay ethnicity, and males outnumbered females in our sample by 502 subjects. The median LOS of our in-patients was 3 days. Sex, ethnicity, age, reason for admission, and American Society of Anesthesiology (ASA) classification were factors that significantly affected LOS. Conclusion: The median LOS reported in this study was 3 days. LOS was significantly affected by sex, ethnicity, age, reason of admission and ASA classification.

Propagation Characteristics of Acoustic Emission in Plate Structure with Various Materials and Multilayer Medium

Kuanfang He,Zhi Tan,Yong Cheng,Chao Wang 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.6

Acoustic emission signal is a kind of elastic wave which is caused by the release of internal energy of materials when the structure changes. The propagation characteristics of acoustic emission is important to the testing technology of a structure by acoustic emission signal. The finite element method is introduced to analyze elastic wave propagation in plate structure in the article, which mainly contains the discretization techniques of the area and time domain. The structure plate with different materials ,style and coating metal are selected in finite element simulation, the displacement contours and wave curve resulted from simulation are used to analyze the interface reflection, refraction and diffraction process as well as the wave type conversion in different medium of the elastic wave propagation . The mechanical pencil lead fracture experiment is done to verify the transient simulation of elastic wave propagation in plate structure.

Terahertz Computed Tomorgraphy with a Quantum Cascade Laser and a Quantum-well Photodetector

Tao Zhou,Li Gu,Zhi-Yong Tan,Jun Cheng Cao 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.2

In this letter, a terahertz (THz) tomography system based on a quantum cascade laser (QCL)and a quantum-well photodetector (QWP) is demonstrated. The QCL provides a relatively high power (a few microwatts) in a continuous-wave mode at 3.9 THz as a light source, and the QWP provides a narrow response range from 3 to 7 THz with a calibrated peak response of 0.5 A/W under background-limited performance. We employ the widely-used filtered back projection (FBP)and algebraic reconstruction algorithms for terahertz tomography technology. The reconstructed cross-sectional image of a sample has successfully revealed the internal and the external structures with a resolution of around 1.5 mm. This experiment demonstrates that the terahertz QCL and the photodetector are potentially useful for terahertz tomography applications.

Chinoketides A and B, Two New Antimicrobial Polyketides from the Endophytes of Distylium chinense with the "Black-Box" Co-culture Method

Meng-Meng Lv,Ming-Hui Tan,Li-Wen Lu,Rong-Hua Zhang,Zhi-Yong Guo,Cheng-Xiong Liu,Jin Yang,Kun Zou,Peter Proksch 한국생약학회 2018 Natural Product Sciences Vol.24 No.3

Two new polyketides, chinoketides A and B (1 - 2) with a known compound xylarphthalide A (3), were isolated from the solid medium of the endophytes from the leaves of the relic plant Distylium chinense with the "black-box" co-culture method, and the structures of two new compounds were elucidated by NMR, MS and CD spectra. And the absolute configurations of chinoketides A (1) and B (2) were determined as 2R,3R,8S and 5R,6S by calculating their ECD spectra to compare with the experimental CD spectra. Finally, the antimicrobial activities were evaluated to Erwinia carotovora sub sp. Carotovora (Jones) Bersey et al, and the results showed that compounds 1 - 3 displayed the antimicrobial activities with MIC value at 20.5, 30.4 and 10.2 mg/mL.

Taper-free and kinked germanium nanowires grown on silicon via purging and the two-temperature process

Kim, Jung Hyuk,Moon, So Ra,Kim, Yong,Chen, Zhi Gang,Zou, Jin,Choi, Duk Yong,Joyce, Hannah J,Gao, Qiang,Tan, H Hoe,Jagadish, Chennupati IOP Pub 2012 Nanotechnology Vol.23 No.11

<P>We investigate the growth procedures for achieving taper-free and kinked germanium nanowires epitaxially grown on silicon substrates by chemical vapor deposition. Singly and multiply kinked germanium nanowires consisting of ⟨111⟩ segments were formed by employing a reactant gas purging process. Unlike non-epitaxial kinked nanowires, a two-temperature process is necessary to maintain the taper-free nature of segments in our kinked germanium nanowires on silicon. As an application, nanobridges formed between (111) side walls of V-grooved (100) silicon substrates have been demonstrated.</P>

Direct ethanol production from dextran industrial waste water by Zymomonas mobilis

Ming-xiong He,Han Qin,Xiao-bo Yin,Zhi-yong Ruan,Fu-rong Tan,Bo Wu,Zong-xia Shui,Li-chun Dai,Qi-chun Hu 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.11

The direct production of ethanol from dextran industrial waste water was investigated by using Zymomonasmobilis via batch and semi-continuous fermentation mode. In batch fermentation, pretreated waste water (unsterilizedand sterilized), pH value (3.8 and 6.0), and Mg2+(with and without) was compared with OD600, sugar and ethanol con-centration. After 24 h fermentation, sugar in the dextran waste water was almost exhausted, and the amount of ethanolaccumulated reached 24.33-29.92 g/l, which is nearly 99% of the theoretical yield of ethanol. Kinetic parameters ofZ. mobilis in batch fermentation were also investigated. The raw dextran waste water was also used in semi-continuousfermentation. After 48 h fermentation, the production of ethanol was 28.65 g/l. These results indicated that dextranwaste water may be used as a candidate substrate and Z. mobilis could convert the raw material into ethanol directly.

Upregulation and biological function of transmembrane protein 119 in osteosarcoma

Zhen-Huan Jiang,Jun Peng,Hui-Lin Yang,Xing-Li Fu,Jin-Zhi Wang,Lei Liu,Jian-Nong Jiang,Yong-Fei Tan,Zhi-Jun Ge 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Osteosarcoma is suggested to be caused by genetic and molecular alterations that disrupt osteoblast differentiation. Recent studies have reported that transmembrane protein 119 (TMEM119) contributes to osteoblast differentiation and bone development. However, the level of TMEM119 expression and its roles in osteosarcoma have not yet been elucidated. In the present study, TMEM119 mRNA and protein expression was found to be up-regulated in osteosarcoma compared with normal bone cyst tissues. The level of TMEM119 protein expression was strongly associated with tumor size, clinical stage, distant metastasis and overall survival time. Moreover, gene set enrichment analysis (GSEA) of the Gene Expression Omnibus (GEO) GSE42352 dataset revealed TMEM119 expression in osteosarcoma tissues to be positively correlated with cell cycle, apoptosis, metastasis and TGF-β signaling. We then knocked down TMEM119 expression in U2OS and MG63 cells using small interfering RNA, which revealed that downregulation of TMEM119 could inhibit the proliferation of osteosarcoma cells by inducing cell cycle arrest in G0/G1 phase and apoptosis. We also found that TMEM119 knockdown significantly inhibited cell migration and invasion, and decreased the expression of TGF-β pathway-related factors (BMP2, BMP7 and TGF-β). TGF-β application rescued the inhibitory effects of TMEM119 knockdown on osteosarcoma cell migration and invasion. Further in vitro experiments with a TGF-β inhibitor (SB431542) or BMP inhibitor (dorsomorphin) suggested that TMEM119 significantly promotes cell migration and invasion, partly through TGF-β/BMP signaling. In conclusion, our data support the notion that TMEM119 contributes to the proliferation, migration and invasion of osteosarcoma cells, and functions as an oncogene in osteosarcoma.