A new non-randomized multi-category response model for surveys with a single sensitive question: Design and analysis

Man-Lai Tang,Guo-Liang Tian,Nian-Sheng Tang,Zhenqiu Liu 한국통계학회 2009 Journal of the Korean Statistical Society Vol.38 No.4

In this article, we develop a non-randomized multi-category response model for a single sensitive survey question with multiple outcomes. Unlike existing randomized response models, our proposed model does not require any randomizing device and the respondents are merely asked to answer a non-sensitive question. It thus reduces cost, ensures reproducibility of respondents' answer (i.e., the same respondent gives the same answer if the survey is re-conducted under the non-randomized multi-category model), enhances respondents' trust on the privacy policy, and motivates respondents' cooperation. We show maximum likelihood estimates (MLEs) of cell probabilities can be obtained in closed- form. Bootstrap standard errors and confidence intervals (CIs) of the cell probabilities or their functions are then given. Bayesian estimation via the data augmentation algorithm is developed when prior information on the parameters of interest is available. Simulation studies are conducted to evaluate the performance of the MLEs and CI estimates. A real data set from a questionnaire on sexual activities in Korean adolescents is used to illustrate the proposed design and analysis methods.

Surgical Management of Intestinal Obstruction from Phytobezoar

Man Hon Tang,Gregory Heng 대한외상중환자외과학회 2019 Journal of Acute Care Surgery Vol.9 No.2

Purpose: Phytobezoar is the most common type of bezoar, which can occasionally present as an intestinal obstruction. In this study, the surgical experience and outcome in the management of intestinal obstruction caused by bezoars are described. Methods: A retrospective analysis of all operative cases of bezoars (n = 36) at Khoo Tech Puat hospital between 2011–2017 was performed. Patient demographics, imaging and operative findings, characteristics of bezoars and related morbidities were analyzed. The study population was subdivided into 2 groups based on operative intervention (fragmentation and milking of bezoars, versus enterotomy and/or bowel resection). Results: There were 36 cases of bezoars in 35 patients that were included in this study. Computed tomography scans were diagnostic of bezoars in 27 cases (75%). There were 20 cases (55.6%) that underwent fragmentation and milking of bezoars. The remaining 16 cases (44.4%) required an enterotomy or bowel resection. Bezoars that required enterotomy / bowel resection were more likely to be distally located in the ileum (75% vs 40%, p = 0.01), larger in volume (86.5 mL vs 63 mL, p = 0.04), with significant increase in morbidity rates (43.8% vs 5%, p < 0.01) compared with all other cases of bezoars. Conclusion: Risk factors for enterotomy / bowel resection in bezoar bowel obstruction include, nondiagnostic computed tomography scans, distally located, and larger volumes of bezoars. Fragmentation and milking should be attempted first as it has lower morbidity rates than enterotomy / bowel resection surgery.

IRS-2 Partially Compensates for the Insulin Signal Defects in IRS-1^-/- Mice Mediated by miR-33

Tang, Chen-Yi,Man, Xiao-Fei,Guo, Yue,Tang, Hao-Neng,Tang, Jun,Zhou, Ci-La,Tan, Shu-Wen,Wang, Min,Zhou, Hou-De Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.2

Insulin signaling is coordinated by insulin receptor substrates (IRSs). Many insulin responses, especially for blood glucose metabolism, are mediated primarily through Irs-1 and Irs-2. Irs-1 knockout mice show growth retardation and insulin signaling defects, which can be compensated by other IRSs in vivo; however, the underlying mechanism is not clear. Here, we presented an Irs-1 truncated mutated mouse ($Irs-1^{-/-}$) with growth retardation and subcutaneous adipocyte atrophy. $Irs-1^{-/-}$ mice exhibited mild insulin resistance, as demonstrated by the insulin tolerance test. Phosphatidylinositol 3-kinase (PI3K) activity and phosphorylated Protein Kinase B (PKB/AKT) expression were elevated in liver, skeletal muscle, and subcutaneous adipocytes in Irs-1 deficiency. In addition, the expression of IRS-2 and its phosphorylated version were clearly elevated in liver and skeletal muscle. With miRNA microarray analysis, we found miR-33 was down-regulated in bone marrow stromal cells (BMSCs) of $Irs-1^{-/-}$ mice, while its target gene Irs-2 was up-regulated in vitro studies. In addition, miR-33 was down-regulated in the presence of Irs-1 and which was up-regulated in fasting status. What's more, miR-33 restored its expression in re-feeding status. Meanwhile, miR-33 levels decreased and Irs-2 levels increased in liver, skeletal muscle, and subcutaneous adipocytes of $Irs-1^{-/-}$ mice. In primary cultured liver cells transfected with an miR-33 inhibitor, the expression of IRS-2, PI3K, and phosphorylated-AKT (p-AKT) increased while the opposite results were observed in the presence of an miR-33 mimic. Therefore, decreased miR-33 levels can up-regulate IRS-2 expression, which appears to compensate for the defects of the insulin signaling pathway in Irs-1 deficient mice.

Endoscopic Findings in Patients Under the Age of 40 Years with Hematochezia in Singapore

Man Hon Tang,Fung Joon Foo,Chee Yung Ng 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.4

Background/Aims: Sigmoidoscopy is performed in most medical centers to evaluate the distal colons of young adults presentingwith hematochezia who are at risk of developing proximal lesions. Colonoscopies offer more complete evaluations but are associatedwith a higher incidence of complications and possible low yield. Methods: An analysis was conducted on colonoscopies performed in our center on patients 40 years of age or younger. The studypopulation was sub-divided into 2 age groups for analysis: <30 years of age and 30–39 years of age. Results: We recruited 453 patients for the study. Patients were 115 and 338 individuals that were <30 and 30–39 years of age,respectively. Hemorrhoids was identified as the cause of bleeding in the majority of cases. The overall incidence of polyps was 6.5%;this was significantly higher in the 30–39 age group (7.4% vs. 1.7%, p=0.026). There were two cases of advanced/malignant polyps. While the majority of the polyps were in the distal colon, 28% of the polyps in the older age group were found in the proximal colon. There was one case of colonic perforation. Conclusions: Colonic polyps are more prevalent in patients aged 30–39. Colonoscopies should be considered for patients over theage of 30 with rectal bleeding.

An Unusual Case of Ovarian Carcinomatosis with Microscopic Tumor Embolism Leading to Rectal Ischemia and Perforation

Man Hon Tang,Jason Lim,Inny Bushmani,Chee Yung Ng 대한소화기내시경학회 2018 Clinical Endoscopy Vol.51 No.3

We present an unusual case of advanced ovarian carcinoma with postoperative complications of ischemia and perforation of therectum as a result of tumor embolism. The interval progression from ischemia to infarction of the rectum was captured in repeatedsigmoidoscopies. A brief discussion on tumor embolism and management of this case is also included.

IRS-2 Partially Compensates for the Insulin Signal Defects in IRS-1−/−Mice Mediated by miR-33

Chen-Yi Tang,Xiao-Fei Man,Yue Guo,Hao-Neng Tang,Jun Tang,Ci-La Zhou,Shu-Wen Tan,Min Wang,Hou-De Zhou 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.2

Insulin signaling is coordinated by insulin receptor substrates (IRSs). Many insulin responses, especially for blood glucose metabolism, are mediated primarily through Irs-1 and Irs-2. Irs-1 knockout mice show growth retardation and insulin signaling defects, which can be compensated by other IRSs in vivo; however, the underlying mechanism is not clear. Here, we presented an Irs-1 truncated mutated mouse (Irs-1−/−) with growth retardation and subcutaneous adipocyte atrophy. Irs-1−/− mice exhibited mild insulin resistance, as demonstrat-ed by the insulin tolerance test. Phosphatidylino-sitol 3-kinase (PI3K) activity and phosphorylated Protein Kinase B (PKB/AKT) expression were elevated in liver, skeletal muscle, and subcu-taneous adipocytes in Irs-1 deficiency. In addition, the expression of IRS-2 and its phosphorylated version were clearly elevated in liver and skeletal muscle. With miRNA microarray analysis, we found miR-33 was down-regulated in bone marrow stromal cells (BMSCs) of Irs-1−/− mice, while its target gene Irs-2 was up-regulated in vitro studies. In addition, miR-33 was down-regulated in the presence of Irs-1 and which was up-regulated in fasting status. What’s more, miR-33 restored its expression in re-feeding status. Meanwhile, miR-33 levels decreased and Irs-2 levels increased in liver, skeletal muscle, and subcutaneous adipocytes of Irs-1−/− mice. In primary cultured liver cells transfected with an miR-33 inhibitor, the expression of IRS-2, PI3K, and phosphorylated-AKT (p-AKT) increased while the opposite results were observed in the presence of an miR-33 mimic. Therefore, decreased miR-33 levels can up-regulate IRS-2 expression, which appears to compensate for the defects of the insulin signaling pathway in Irs-1 deficient mice.

A newPlagiotrochus Mayr oak gall wasp species from Taiwan (Hymenoptera: Cynipidae: Cynipini)

Chang-Ti Tang,Man-Miao Yang,GrahamN. Stone,James A. Nicholls,George Melika 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2

A new species of oak gall wasp, Plagiotrochus tarokoensis Tang and Melika sp. nov., is described fromTaiwan. The species induces integral leaf galls on Quercus tarokoensis (Fagaceae). Data on the diagnosis, distribution, and biology of the new species are given. This is the second known Plagiotrochus species from the Oriental region and the first one known to associate with the Ilex group of section Cerris oaks within Quercus linnaeus subgenus Quercus.

Numerical investigations on cavitating flows with thermodynamic effects in a diffuser-type centrifugal pump

Tang Xue-lin,Bian Li-yuan,Wang Fu-jun,Li Xiao-qin,Hao Man 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

A cavitation model with thermodynamic effects for cavitating flows in a diffuser-type centrifugal pump is developed based on the bubble two-phase flow model. The proposed cavitation model includes mass, momentum, and energy transportations according to the thermodynamic mechanism of cavitation. Numerical simulations are conducted inside the entire passage of the centrifugal pump by using the proposed cavitation model and the renormalization group-based k −ε turbulent model coupled with the energy transportation equation. By using the commercial computational fluid dynamics software FLUENT 6.3, we have shown that the predicted performance characteristics of the pump, as well as the pressure, vapor, and density distributions in the impeller, agree well with that calculated by the full cavitation model. Simulation results show that cavitation initially occurs slightly behind the inlet of the blade suction surface, i.e., the area with maximum vapor concentration and minimum pressure. The predicted temperature field shows that the reduction in temperature restrains the growth of cavitating bubbles. Therefore, the thermodynamic effect should be treated as a necessary factor in cavitation models. Comparison results validate the efficiency and accuracy of the numerical technique in simulating cavitation flows in centrifugal pumps.

Synthesis, Crystal Structures and Properties of Two Binuclear Supramolecular Complexes Based on Biphenyl-2,2'-dicarboxylic Acid Ligand

Tang, Jin-Niu,Pan, Gang-Hong,Li, Long,Tian, Wei-Man,Huang, Zhong-Jing Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.2

Two novel binuclear metal-organic coordination complexes [$Cd_2(Hdpa)_4(bpy)_2$] (1), [$Dy_2(dpa)_2(bpy)_2(NO_3)_2-(H_2O)_2$](bpy) (2) (where $H_2dpa$ = biphenyl-2,2'-dicarboxylic acid, bpy = 2,2'-bipyridine) have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, spectral method (IR), elemental analysis (EA), powder X-ray diffraction (XRD), electronic spectra (UV-vis), fluorescent in the solid state and thermogravimetric analysis (TGA). Complexes 1-2 crystallizes isomorphously in the Triclinic space group P-1. The ${\pi}-{\pi}$ stacking interactions and hydrogen-bonds play a vital role in determining the crystal packing and construction of the extended 3-D supramolecular network.

In situ Synthesis, Crystal Structure, XPS and Fluorescent Property of a Novel Two-Dimensional Binuclear Copper(I) Tetrazole Complex

Tang, Yun-Zhi,Huang, Jun,Zhou, Man,Deng, Yun-Pan,Xu, Qing,Wen, He-Rui Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1