352 results on '"Lin, M-C."'
Search Results
2. Investigation of Product Formation in the O( 1 D, 3 P) + N 2 O Reactions: Comparison of Experimental and Theoretical Kinetics.
- Author
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Pham TV and Lin MC
- Abstract
The spin-forbidden and spin-allowed reactions of the excited and ground electronic state O(
1 D,3 P) + N2 O( X1 Σ+ ) systems have been studied theoretically. Quantum calculations at the UCCSD(T)/CBS(T, Q, 5)//CCSD/aug-cc-pVTZ level have located two crossing points, MSX1 and MSX2, with energies of 11.2 and 22.7 kcal mol-1 above O(3 P) + N2 O, respectively. The second-order P-independent rate constants for the adiabatic and non-adiabatic thermal reactions predicted by adiabatic TST/VTST and non-adiabatic TST, respectively, agree closely with the available literature results. The second-order rate constant, k2a = 9.55 × 10-11 exp(-26.09 kcal mol-1 /RT) cm3 molecule-1 s-1 , for the O(3 P) + N2 O → 2NO reaction, contributed by both the dominant MSX2 and the minor TS1-a channels, is in reasonable accord with prior experiments and recommendations, covering the temperature range of 1200-4100 K. The calculated rate constant, k2b = 4.47 × 10-12 exp(-12.9 kcal mol-1 /RT) cm3 molecule-1 s-1 , for the O(3 P) + N2 O → N2 + O2 (a1 Δg ) reaction, occurring exclusively via MSX1, is also in good agreement with the combined experimental data measured in a shock tube study at T = 1940-3340 K (ref 16) and the result measured by Fourier transform infrared spectroscopy in the temperature range of 988-1083 K (ref 17). Moreover, the spin-allowed rate constants predicted for the singlet-state reactions, k1a = (7.06-7.46) × 10-11 cm3 molecule-1 s-1 for O(1 D) + N2 O → 2NO and k1b = (4.36-4.66) × 10-11 cm3 molecule-1 s-1 for O(1 D) + N2 O → N2 + O2 (a1 Δg ) in the temperature range of 200-350 K, agree quantitatively with the experimentally measured data, while the total rate constant k1 = k1a + k1b was also found to be in excellent accordance with many reported values.- Published
- 2022
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3. Intravenous tissue plasminogen activator for acute ischemic stroke in patients with renal dysfunction.
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Wang IK, Yen TH, Chen CH, Hsu SP, Sun Y, Lien LM, Chang WL, Lai TC, Chen PL, Chen CC, Huang PH, Lin CH, Su YC, Lin MC, Li CY, Sung FC, and Hsu CY
- Subjects
- Fibrinolytic Agents adverse effects, Humans, Retrospective Studies, Thrombolytic Therapy, Tissue Plasminogen Activator adverse effects, Treatment Outcome, Brain Ischemia complications, Brain Ischemia drug therapy, Ischemic Stroke, Kidney Diseases, Stroke complications, Stroke drug therapy
- Abstract
Objective: This study used the Taiwan Stroke Registry data to evaluate the efficacy and safety of intravenous tissue plasminogen activator (tPA) in treating acute ischemic stroke in patients with renal dysfunction., Design: We identified 3525 ischemic stroke patients and classified them into two groups according to the estimated glomerular filtration rate (eGFR) at the emergency department: ≥60, and <60 ml/min/1.73 m2 or on dialysis and by the propensity score from August 2006 to May 2015. The odds ratio of poor functional outcome (modified Rankin Scale ≥2) was calculated for patients with tPA treatment (N = 705), compared to those without tPA treatment (N = 2820), by eGFR levels, at 1, 3 and 6 months after ischemic stroke. We also evaluated the risks of intracerebral hemorrhage, upper gastrointestinal bleeding, mortality, between the two groups by eGFR levels., Results: Among patients with eGFR levels of <60 ml/min/1.73 m2, tPA therapy reduced the odds ratio of poor functional outcome to 0.60 (95% confidence interval = 0.42-0.87) at 6 months after ischemic stroke. The tPA therapy was not associated with increased overall risk of upper gastrointestinal bleeding, but with increased risk of intracerebral hemorrhage. The low eGFR was not a significant risk factor of intracerebral hemorrhage among ischemic stroke patients receiving tPA treatment., Conclusions: tPA for acute ischemic stroke could improve functional outcomes without increasing the risks of upper gastrointestinal bleeding for patients with or without renal dysfunction. The low eGFR was not a significant risk factor for intracerebral hemorrhage among patients receiving tPA treatment., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2022
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4. Increased incidence and recurrence rates of acute diverticulitis in patients with irritable bowel syndrome.
- Author
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Hsu SM, Lin HJ, Lin MC, and Huang ST
- Subjects
- Cohort Studies, Humans, Incidence, Retrospective Studies, Risk Factors, Diverticulitis, Irritable Bowel Syndrome complications, Irritable Bowel Syndrome epidemiology
- Abstract
Aim: Acute diverticulitis (AD) is commonly diagnosed in outpatient and emergency departments and is associated with severe complications such as perforation and fistula. Symptoms of irritable bowel syndrome (IBS), such as abdominal pain, constipation and diarrhoea, are also common with AD. This study aimed to evaluate the strength of a possible association between IBS and AD., Method: This retrospective study analysed records from Taiwan's National Health Insurance Research Database and involved a total of 25 810 patients, including 12 905 IBS patients diagnosed between 2000 and 2012. The IBS and non-IBS cohorts were matched by propensity score for age, gender, comorbidities and medication, then compared for confounding variables by the chi-square test or Student's t-test. The association between AD and IBS was determined using Cox proportional hazards models. Kaplan-Meier curves assessed the cumulative incidence of AD in IBS patients., Results: The overall incidence of AD was 3.95-fold higher in the IBS cohort than in the non-IBS cohort (63.34 vs 16.02 per 100 000 person-years, respectively) and IBS was an independent risk factor for subsequent diagnosis of AD in multivariate Cox proportional hazards regression model adjusted hazards ratio (aHR = 3.84, 95% CI = 2.29-6.44, P < 0.001) and Kaplan-Meier (log-rank test, P < 0.001) analysis. IBS was also associated with a high recurrence rate of AD (aHR = 8.30, 95% CI = 1.07-64.30, P = 0.04)., Conclusion: The epidemiological evidence in this study demonstrates that patients with IBS are associated with a higher incidence of AD and also its recurrence., (© 2020 The Association of Coloproctology of Great Britain and Ireland.)
- Published
- 2020
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5. Effective strategies to prevent coronavirus disease-2019 (COVID-19) outbreak in hospital.
- Author
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Lee IK, Wang CC, Lin MC, Kung CT, Lan KC, and Lee CT
- Subjects
- Betacoronavirus, COVID-19, China, Humans, Pandemics, Pneumonia, Viral, SARS-CoV-2, Coronavirus, Coronavirus Infections epidemiology
- Published
- 2020
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6. Retrospective analysis of the association between tooth loss and dementia: a population-based matched case-control study.
- Author
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Tsai YC, Wang HJ, Wang LY, Shaw CK, Lee YP, Lin MC, and Huang CH
- Subjects
- Aged, Case-Control Studies, Humans, Middle Aged, Retrospective Studies, Risk Factors, Taiwan, Dementia, Tooth Loss
- Abstract
Objective: To clarify the association between multiple tooth loss and dementia., Basic Research Design: Case-control study based on the claims data from National Health Insurance Research Database (NHIRD). Patients were divided into two groups: the dementia groups and non-dementia group. For each case patient, one control patient was randomly selected and frequency matched by age (per 5 years) and sex. The case group comprised patients newly diagnosed with dementia, and the index date was the the date of dementia diagnosis, which became the baseline for comorbidity and age calculations., Results: Among the 43,026 individuals, patients with dementia had a significantly higher extraction density at ages 60-69 (p ⟨ 0.0001) and 70-79 (p = 0.04) years compared with control patients., Conclusions: This population-based retrospective study demonstrated an association between tooth loss and dementia. Patients in Taiwan with more tooth extraction experience are likely to have an increased risk of dementia., (Copyright© 2020 Dennis Barber Ltd.)
- Published
- 2020
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7. Potassium-Presenting Zinc Oxide Surfaces Induce Vertical Phase Separation in Fullerene-Free Organic Photovoltaics.
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Cheng HW, Raghunath P, Wang KL, Cheng P, Haung T, Wu Q, Yuan J, Lin YC, Wang HC, Zou Y, Wang ZK, Lin MC, Wei KH, and Yang Y
- Abstract
Bulk heterojunction (BHJ) structure based organic photovoltaics (OPVs) have recently showed great potential for achieving high power conversion efficiencies (PCEs). An ideal BHJ structure would feature large donor/acceptor interfacial areas for efficient exciton dissociation and gradient distributions with high donor and acceptor concentrations near the anode and cathode, respectively, for efficient charge extraction. However, the random mixing of donors and acceptors in the BHJ often suffers the severe charge recombination in the interface, resulting in poor charge extraction. Herein, we propose a new approach-treating the surface of the zinc oxide (ZnO) as an electron transport layer with potassium hydroxide-to induce vertical phase separation of an active layer incorporating the nonfullerene acceptor IT-4F. Density functional theory calculations suggested that the binding energy difference between IT-4F and the PBDB-T-2Cl, to the potassium (K)-presenting ZnO interface, is twice as strong as that for IT-4F and PBDB-T-2Cl to the untreated ZnO surface, such that it would induce more IT-4F moving toward the K-presenting ZnO interface than the untreated ZnO interface thermodynamically. Benefiting from efficient charge extraction, the best PCEs increased to 12.8% from 11.8% for PBDB-T-2Cl:IT-4F-based devices, to 12.6% from 11.6% for PBDB-T-2Cl:Y1-4F-based devices, to 13.5% from 12.2% for PBDB-T-2Cl:Y6-based devices, and to 15.7% from 15.1% for PM6:Y6-based devices.
- Published
- 2020
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8. Computational Study on the Mechanisms and Rate Constants for the O( 3 P, 1 D) + OCS Reactions.
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Chen HT, Pham TV, and Lin MC
- Abstract
The mechanisms and kinetics of O(
3 P,1 D) + OCS(X1 Σ+ ) reactions have been studied by the high-level G2M(CC2) and CCSD(T)/6-311+G(3df)//B3LYP/6-311+G(3df) methods in conjunction with the transition-state theory and variational Rice-Ramsperger-Kassel-Marcus theory calculations. The result shows that the triplet surface proceeds directly by abstraction and substitution channels to produce SO(3 P) + CO(X1 Σ+ ) and S(3 P) + CO2 (X1 Σg + ) by passing the barriers of 7.6 and 9.1 kcal·mol-1 at the G2M(CC2)//B3LYP/6-311+G(3df) level, respectively, while two stable intermediates, LM1 (OSCO1 ) and LM2 (SC(O)O1 ), are formed barrierlessly from O(1 D) + OCS(X1 Σ+ ) in the singlet surface, which lie at -40.5 and -50.1 kcal·mol-1 relative to O(3 P) + OCS(X1 Σ+ ) reactants and decompose to CO(X1 Σ+ ) + SO(a1 Δ) and S(1 D) + CO2 (X1 Σg + ). LM1 and LM2 may also be produced by singlet-triplet surface crossings via MSX1 and MSX2; the predicted total rate constant for the O(3 P) + OCS(X1 Σ+ ) reaction including the crossings, 9.2 × 10-11 exp(-5.18 kcal·mol-1 / RT ) cm3 molecule-1 s-1 , is in good agreement with available experimental data. The branching ratio of the CO2 product channel, 0.22-0.32, between 1200 and 1600 K, is also in excellent agreement with the value of 0.2-0.3 measured by Isshiki et al. ( J. Phys. Chem. A. 2003, 107, 2464).- Published
- 2019
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9. Infrared Emission from Photodissociation of Methyl Formate [HC(O)OCH 3 ] at 248 and 193 nm: Absence of Roaming Signature.
- Author
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Lanfri L, Wang YL, Pham TV, Nguyen NT, Paci MB, Lin MC, and Lee YP
- Abstract
Following photodissociation at 248 nm of gaseous methyl formate (HC(O)OCH
3 , 0.73 Torr) and Ar (0.14 Torr), temporally resolved vibration-rotational emission spectra of highly internally excited CO (ν ≤ 11, J ≤ 27) in the 1850-2250 cm-1 region were recorded with a step-scan Fourier-transform spectrometer. The vibration-rotational distribution of CO is almost Boltzmann, with a nascent average rotational energy ( ER 0 ) of 3 ± 1 kJ mol-1 and a vibrational energy ( EV 0 ) of 76 ± 9 kJ mol-1 . With 3 Torr of Ar added to the system, the average vibrational energy was decreased to EV 0 = 61 ± 7 kJ mol-1 . We observed no distinct evidence of a bimodal rotational distribution for ν = 1 and 2, as reported previously [Lombardi et al., J. Phys. Chem. A 2016 , 129 , 5155], as evidence of a roaming mechanism. The vibrational distribution with a temperature of ∼13000 ± 1000 K, however, agrees satisfactorily with trajectory calculations of these authors, who took into account conical intersections from the S1 state. Highly internally excited CH3 OH that is expected to be produced from a roaming mechanism was unobserved. Following photodissociation at 193 nm of gaseous HC(O)OCH3 (0.42 Torr) and Ar (0.09 Torr), vibration-rotational emission spectra of CO (ν ≤ 4, J ≤ 38) and CO2 (with two components of varied internal distributions) were observed, indicating that new channels are open. Quantum-chemical calculations, computed at varied levels of theory, on the ground electronic potential-energy schemes provide a possible explanation for some of our observations. At 193 nm, the CO2 was produced from secondary dissociation of the products HC(O)O and CH3 OCO, and CO was produced primarily from secondary dissociation of the product HCO produced on the S1 surface or the decomposition to CH3 OH + CO on the S0 surface.- Published
- 2019
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10. Carbon-doped SnS 2 nanostructure as a high-efficiency solar fuel catalyst under visible light.
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Shown I, Samireddi S, Chang YC, Putikam R, Chang PH, Sabbah A, Fu FY, Chen WF, Wu CI, Yu TY, Chung PW, Lin MC, Chen LC, and Chen KH
- Abstract
Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS
2 (SnS2 -C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS2 lattice, resulting in different photophysical properties as compared with undoped SnS2 . This SnS2 -C photocatalyst significantly enhances the CO2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS2 -C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO2 reduction under visible light, where the in situ carbon-doped SnS2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.- Published
- 2018
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11. Ni-Nanocluster Modified Black TiO 2 with Dual Active Sites for Selective Photocatalytic CO 2 Reduction.
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Billo T, Fu FY, Raghunath P, Shown I, Chen WF, Lien HT, Shen TH, Lee JF, Chan TS, Huang KY, Wu CI, Lin MC, Hwang JS, Lee CH, Chen LC, and Chen KH
- Abstract
One of the key challenges in artificial photosynthesis is to design a photocatalyst that can bind and activate the CO
2 molecule with the smallest possible activation energy and produce selective hydrocarbon products. In this contribution, a combined experimental and computational study on Ni-nanocluster loaded black TiO2 (Ni/TiO2[Vo] ) with built-in dual active sites for selective photocatalytic CO2 conversion is reported. The findings reveal that the synergistic effects of deliberately induced Ni nanoclusters and oxygen vacancies provide (1) energetically stable CO2 binding sites with the lowest activation energy (0.08 eV), (2) highly reactive sites, (3) a fast electron transfer pathway, and (4) enhanced light harvesting by lowering the bandgap. The Ni/TiO2[Vo] photocatalyst has demonstrated highly selective and enhanced photocatalytic activity of more than 18 times higher solar fuel production than the commercial TiO2 (P-25). An insight into the mechanisms of interfacial charge transfer and product formation is explored., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2018
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12. EZH2-mediated upregulation of ROS1 oncogene promotes oral cancer metastasis.
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Shih CH, Chang YJ, Huang WC, Jang TH, Kung HJ, Wang WC, Yang MH, Lin MC, Huang SF, Chou SW, Chang E, Chiu H, Shieh TY, Chen YJ, Wang LH, and Chen L
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- Animals, Biomarkers, Tumor metabolism, Carcinoma, Squamous Cell drug therapy, Cell Line, Tumor, Cell Proliferation, Chemokine CXCL1 metabolism, Down-Regulation, ErbB Receptors antagonists & inhibitors, Histones metabolism, Humans, Male, Methylation, Mice, Molecular Targeted Therapy methods, Mouth Neoplasms drug therapy, Protein-Tyrosine Kinases antagonists & inhibitors, Proto-Oncogene Proteins antagonists & inhibitors, STAT1 Transcription Factor metabolism, Up-Regulation, Xenograft Model Antitumor Assays, Zinc Finger Protein GLI1 metabolism, Carcinoma, Squamous Cell genetics, Carcinoma, Squamous Cell pathology, Enhancer of Zeste Homolog 2 Protein metabolism, Gene Expression Regulation, Neoplastic, Lung Neoplasms secondary, Mouth Neoplasms genetics, Mouth Neoplasms pathology, Protein-Tyrosine Kinases metabolism, Proto-Oncogene Proteins metabolism
- Abstract
Current anti-epidermal growth factor receptor (EGFR) therapy for oral cancer does not provide satisfactory efficacy due to drug resistance or reduced EGFR level. As an alternative candidate target for therapy, here we identified an oncogene, ROS1, as an important driver for oral squamous cell carcinoma (OSCC) metastasis. Among tumors from 188 oral cancer patients, upregulated ROS1 expression strongly correlated with metastasis to lung and lymph nodes. Mechanistic studies uncover that the activated ROS1 results from highly expressed ROS1 gene instead of gene rearrangement, a phenomenon distinct from other cancers. Our data further reveal a novel mechanism that reduced histone methyltransferase EZH2 leads to a lower trimethylation of histone H3 lysine 27 suppressive modification, relaxes chromatin, and promotes the accessibility of the transcription factor STAT1 to the enhancer and the intron regions of ROS1 target genes, CXCL1 and GLI1, for upregulating their expressions. Down-regulation of ROS1 in highly invasive OSCC cells, nevertheless, reduces cell proliferation and inhibits metastasis to lung in the tail-vein injection and the oral cavity xenograft models. Our findings highlight ROS1 as a candidate biomarker and therapeutic target for OSCC. Finally, we demonstrate that co-targeting of ROS1 and EGFR could potentially offer an effective oral cancer therapy.
- Published
- 2017
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13. GATA3 interacts with and stabilizes HIF-1α to enhance cancer cell invasiveness.
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Lin MC, Lin JJ, Hsu CL, Juan HF, Lou PJ, and Huang MC
- Abstract
This corrects the article DOI: 10.1038/onc.2017.8.
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- 2017
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14. GATA3 interacts with and stabilizes HIF-1α to enhance cancer cell invasiveness.
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Lin MC, Lin JJ, Hsu CL, Juan HF, Lou PJ, and Huang MC
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- Animals, Blotting, Western, Carcinoma, Squamous Cell metabolism, Cell Hypoxia, Chromatin Immunoprecipitation, Female, Gene Expression Regulation, Neoplastic physiology, Head and Neck Neoplasms metabolism, Heterografts, Humans, Immunohistochemistry, Immunoprecipitation, Mice, Mice, Inbred NOD, Mice, SCID, Real-Time Polymerase Chain Reaction, Squamous Cell Carcinoma of Head and Neck, Carcinoma, Squamous Cell pathology, GATA3 Transcription Factor metabolism, Head and Neck Neoplasms pathology, Hypoxia-Inducible Factor 1, alpha Subunit metabolism, Neoplasm Invasiveness pathology
- Abstract
GATA binding protein 3 (GATA3) is indispensable in development of human organs. However, the role of GATA3 in cancers remains elusive. Hypoxia inducible factor (HIF)-1 plays an important role in pathogenesis of human cancers. Regulation of HIF-1α degradation is orchestrated through collaboration of its interacting proteins. In this study, we discover that GATA3 is upregulated in head and neck squamous cell carcinoma (HNSCC) and is an independent predictor for poor disease-free survival. GATA3 promotes invasive behaviours of HNSCC and melanoma cells in vitro and in immunodeficient mice. Mechanistically, GATA3 physically associates with HIF-1α under hypoxia to inhibit ubiquitination and proteasomal degradation of HIF-1α, which is independent of HIF-1α prolyl hydroxylation. Chromatin immunoprecipitation assays show that the GATA3/HIF-1α complex binds to and regulates HIF-1 target genes, which is also supported by the microarray analysis. Notably, the GATA3-mediated invasiveness can be significantly reversed by HIF-1α knockdown, suggesting a critical role of HIF-1α in the underlying mechanism of GATA3-mediated effects. Our findings suggest that GATA3 stabilizes HIF-1α to enhance cancer invasiveness under hypoxia and support the GATA3/HIF-1α axis as a potential therapeutic target for cancer treatment.
- Published
- 2017
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15. Computational Chemical Kinetics for the Reaction of Criegee Intermediate CH 2 OO with HNO 3 and Its Catalytic Conversion to OH and HCO.
- Author
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Raghunath P, Lee YP, and Lin MC
- Abstract
The kinetics and mechanisms for the reaction of the Criegee intermediate CH
2 OO with HNO3 and the unimolecular decomposition of its reaction product CH2 (O)NO3 are important in atmospheric chemistry. The potential-energy profile of the reactions predicted with the CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ method shows that the initial association yields a prereaction complex that isomerizes by H migration to yield excited intermediate nitrooxymethyl hydroperoxide NO3 CH2 OOH* with internal energy ∼44 kcal mol-1 . A fragmentation of this excited intermediate produces CH2 (O)NO3 + OH with its transition state located 5.0 kcal mol-1 below that of the reactants. Further decomposition of CH2 (O)NO3 produces HCO + HNO3 , forming a catalytic cycle for destruction of CH2 OO by HNO3 . The rate coefficients and product-branching ratios were calculated in the temperature range 250-700 K at pressure 20-760 Torr (N2 ) using the variational-transition-state and Rice-Ramsperger-Kassel-Marcus (RRKM) theories. The predicted total rate coefficient for reaction CH2 OO + HNO3 at 295 K, 5.1 × 10-10 cm3 molecule-1 s-1 , agrees satisfactorily with the experimental value, (5.4 ± 1.0) × 10-10 cm3 molecule-1 s-1 . The predicted branching ratios at 295 K are 0.21 for the formation of NO3 CH2 OOH and 0.79 for CH2 (O)NO3 + OH at a pressure of 40 Torr (N2 ), and 0.79 for the formation of NO3 CH2 OOH and 0.21 for CH2 (O)NO3 + OH at 760 Torr (N2 ). This new catalytic conversion of CH2 OO to HCO + OH by HNO3 might have significant impact on atmospheric chemistry.- Published
- 2017
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16. Pressure drop of two-phase helium along long cryogenic flexible transfer lines to support a superconducting RF operation at its cryogenic test stand.
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Chang MH, Tsai MH, Wang C, Lin MC, Chung FT, Yeh MS, Chang LH, Lo CH, Yu TC, Chen LJ, and Liu ZK
- Abstract
Background: Establishing a stand-alone cryogenic test stand is of vital importance to ensure the highly reliable and available operation of superconducting radio-frequency module in a synchrotron light source. Operating a cryogenic test stand relies strongly on a capability to deliver two-phase helium along long cryogenic transfer lines. A newly constructed cryogenic test stand with flexible cryogenic transfer lines of length 220 m at National Synchrotron Radiation Research Center is required to support a superconducting radio-frequency module operated at 126.0 kPa with a 40-W dynamic load for a long-term reliability test over weeks. It is designed based on a simple analytical approach with the introduction of a so-called tolerance factor that serves to estimate the pressure drops in transferring a two-phase helium flow with a substantial transfer cryogenic heat load. Tolerance factor 1.5 is adopted based on safety factor 1.5 commonly applied in cryogenic designs to estimate the total mass flow rate of liquid helium demanded. A maximum 60-W dynamic load is verified with experiment measured with heater power 60 W instead after the cryogenic test stand has been installed., Results: Aligning the modeled cryogenic accumulated static heat load with the results measured in situ, actual tolerance factor 1.287 is obtained. The feasibility and validity of our simple analytical approach with actual tolerance factor 1.287 have been scrutinized by using five test cases with varied operating conditions. Calculated results show the discrepancies of the pressure drops between the estimated and measured values for both liquid helium and cold gaseous helium transfer lines have an underestimate 0.11 kPa and an overestimate 0.09 kPa, respectively. A discrepancy is foreseen, but remains acceptable for engineering applications from a practical point of view., Conclusions: The simple analytical approach with the introduction of a tolerance factor can provide not only insight into optimizing the choice of each lossy cryogenic piping element of the transfer lines in the design phase but also firm guidance for upgrading the present cryogenic transfer lines for its subsequent application.
- Published
- 2016
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17. Reply to the letter to the editor 'On the tumor risk from dental diagnostic X-ray exposure' by Jargin.
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Lin MC, Lee CF, and Kao CH
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- Humans, Risk, X-Rays, Neoplasms, Radiography, Dental
- Published
- 2016
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18. Black oesophagus.
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Lin MC, Chu HC, and Chen PJ
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- Acute Disease, Aged, Endoscopy, Digestive System, Humans, Male, Necrosis, Risk Factors, Esophagus pathology, Gastrointestinal Hemorrhage drug therapy, Gastrointestinal Hemorrhage etiology, Proton Pump Inhibitors administration & dosage, Sucralfate administration & dosage
- Published
- 2015
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19. Ab Initio Chemical Kinetics for the CH3 + O((3)P) Reaction and Related Isomerization-Decomposition of CH3O and CH2OH Radicals.
- Author
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Xu ZF, Raghunath P, and Lin MC
- Abstract
The kinetics and mechanism of the CH3 + O reaction and related isomerization-decomposition of CH3O and CH2OH radicals have been studied by ab initio molecular orbital theory based on the CCSD(T)/aug-cc-pVTZ//CCSD/aug-cc-pVTZ, CCSD/aug-cc-pVDZ, and G2M//B3LYP/6-311+G(3df,2p) levels of theory. The predicted potential energy surface of the CH3 + O reaction shows that the CHO + H2 products can be directly generated from CH3O by the TS3 → LM1 → TS7 → LM2 → TS4 path, in which both LM1 and LM2 are very loose and TS7 is roaming-like. The result for the CH2O + H reaction shows that there are three low-energy barrier processes including CH2O + H → CHO + H2 via H-abstraction and CH2O + H → CH2OH and CH2O + H → CH3O by addition reactions. The predicted enthalpies of formation of the CH2OH and CH3O radicals at 0 K are in good agreement with available experimental data. Furthermore, the rate constants for the forward and some key reverse reactions have been predicted at 200-3000 K under various pressures. Based on the new reaction pathway for CH3 + O, the rate constants for the CH2O + H and CHO + H2 reactions were predicted with the microcanonical variational transition-state/Rice-Ramsperger-Kassel-Marcus (VTST/RRKM) theory. The predicted total and individual product branching ratios (i.e., CO versus CH2O) are in good agreement with experimental data. The rate constant for the hydrogen abstraction reaction of CH2O + H has been calculated by the canonical variational transition-state theory with quantum tunneling and small-curvature corrections to be k(CH2O + H → CHO + H2) = 2.28 × 10(-19) T(2.65) exp(-766.5/T) cm(3) molecule(-1) s(-1) for the 200-3000 K temperature range. The rate constants for the addition giving CH3O and CH2OH and the decomposition of the two radicals have been calculated by the microcanonical RRKM theory with the time-dependent master equation solution of the multiple quantum well system in the 200-3000 K temperature range at 1 Torr to 100 atm. The predicted rate constants are in good agreement with most of the available data.
- Published
- 2015
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20. 5α-Reductase inhibitors increase acute coronary syndrome risk in patients with benign prostate hyperplasia.
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Chou CH, Lin CL, Lin MC, Sung FC, and Kao CH
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- 5-alpha Reductase Inhibitors administration & dosage, Acute Coronary Syndrome epidemiology, Aged, Aged, 80 and over, Case-Control Studies, Drug Therapy, Combination, Dutasteride administration & dosage, Finasteride administration & dosage, Humans, Male, Middle Aged, National Health Programs statistics & numerical data, Odds Ratio, Prostatic Hyperplasia epidemiology, Risk, Taiwan epidemiology, 5-alpha Reductase Inhibitors adverse effects, Acute Coronary Syndrome chemically induced, Dutasteride adverse effects, Finasteride adverse effects, Prostatic Hyperplasia drug therapy
- Abstract
Background: This study explored the possible association between the use of two typical 5ARIs (finasteride and dutasteride) and the risk of acute coronary syndrome (ACS) in patients with benign prostate hyperplasia (BPH)., Methods: From the claims data of the Taiwan National Health Insurance (NHI) Taiwan, we identified 1843 ACS cases among BPH patients and randomly selected 7330 controls without ACS, with a similar mean age of 73 years. Multivariate logistic regression analysis estimated the odds ratio (OR) and 95 % confidence interval (CI) for the relationship between the 5ARIs medications and ACS risk., Results: We found that BPH patients who had received treatment with both finasteride and dutasteride were at a higher risk of ACS with an OR of 3.47 (95 % CI 1.05-11.5), compared to patients without 5ARIs treatment. Furthermore, the dosage analysis showed that there were no significant associations between ACS risk and uses of a single drug medication regardless the dosages. The ORs for those who took only dutasteride were 1.07 (95 % CI 0.39-2.99) with low dose and 0.73 (95 % CI 0.38-1.44) with high dose. The ORs for those who took only finasteride were 1.30 (95 % CI 0.89-1.92) with low dose and 0.98 (95 % CI 0.19-5.13) with high dose., Conclusion: This population-based nested case-control study suggests that 5ARI use may increase ACS risk among patients with BPH when patients were exposed to both finasteride and dutasteride.
- Published
- 2015
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21. Decreased prevalence of dementia associated with statins: a national population-based study.
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Chuang CS, Lin CL, Lin MC, Sung FC, and Kao CH
- Subjects
- Adult, Aged, Female, Humans, Male, Middle Aged, Prevalence, Taiwan epidemiology, Dementia epidemiology, Dementia prevention & control, Hydroxymethylglutaryl-CoA Reductase Inhibitors pharmacology
- Abstract
Background and Purpose: Dementia is a neurodegenerative disorder that presents a progressive decline in cognitive function and loss of short-term memory with age. Several studies have shown that statin, an oral lipid-lowering drug, may reduce the risk of developing dementia. The objective of this study is to explore the association between statin and the development of dementia., Methods: The data analyzed in this study were retrieved from the National Health Insurance Research Database in Taiwan. The sample consisted of 123 300 patients ≥ 20 years of age, including 61 650 dementia patients with statin use and 61 650 patients without statin use who were eligible for inclusion in this study. Univariate and multivariate Cox proportional hazard regression analyses were performed to measure the effects of statin use on the risk of dementia., Results: The beneficial effect of statin on dementia was significant after adjusting for sociodemographic factors and comorbidities (adjusted hazard ratio of 0.92, 95% confidence interval 0.86-0.98). The sex- and age-specific analysis of adjusted hazard ratios showed a higher beneficial effect from statin treatment in women than in men, and the effect became more significant with age., Conclusion: Statin therapy may help prevent the development of dementia, and both hydrophilic and lipophilic statins produce similar effects. However, the preventive characters and associated mechanisms must be further explored and identified., (© 2014 The Author(s) European Journal of Neurology © 2014 EAN.)
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- 2015
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22. Quantum chemical investigation on the role of Li adsorbed on anatase (101) surface nano-materials on the storage of molecular hydrogen.
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Srinivasadesikan V, Raghunath P, and Lin MC
- Subjects
- Adsorption, Models, Chemical, Models, Molecular, Hydrogen chemistry, Lithium chemistry, Nanostructures, Quantum Theory, Titanium chemistry
- Abstract
Lithiation of TiO2 has been shown to enhance the storage of hydrogen up to 5.6 wt% (Hu et al. J Am Chem Soc 128:11740-11741, 2006). The mechanism for the process is still unknown. In this work we have carried out a study on the adsorption and diffusion of Li atoms on the surface and migration into subsurface layers of anatase (101) by periodic density functional theory calculations implementing on-site Coulomb interactions (DFT+U). The model consists of 24 [TiO2] units with 11.097 × 7.655 Å(2) surface area. Adsorption energies have been calculated for different Li atoms (1-14) on the surface. A maximum of 13 Li atoms can be accommodated on the surface at two bridged O, Ti-O, and Ti atom adsorption sites, with 83 kcal mol(-1) adsorption energy for a single Li atom adsorbed between two bridged O atoms from where it can migrate into the subsurface layer with 27 kcal mol(-1) energy barrier. The predicted adsorption energies for H2 on the lithiated TiO2 (101) surface with 1-10 Li atoms revealed that the highest adsorption energies occurred on 1-Li, 5-Li, and 9-Li surfaces with 3.5, 4.4, and 7.6 kcal mol(-1), respectively. The values decrease rapidly with additional H2 co-adsorbed on the lithiated surfaces; the maximum H2 adsorption on the 9Li-TiO2(a) surface was estimated to be only 0.32 wt% under 100 atm H2 pressure at 77 K. The result of Bader charge analysis indicated that the reduction of Ti occurred depending on the Li atoms covered on the TiO2 surface.
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- 2015
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23. A novel and facile decay path of Criegee intermediates by intramolecular insertion reactions via roaming transition states.
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Nguyen TN, Putikam R, and Lin MC
- Abstract
We have discovered a new and highly competitive product channel in the unimolecular decay process for small Criegee intermediates, CH2OO and anti/syn-CH3C(H)OO, occurring by intramolecular insertion reactions via a roaming-like transition state (TS) based on quantum-chemical calculations. Our results show that in the decomposition of CH2OO and anti-CH3C(H)OO, the predominant paths directly produce cis-HC(O)OH and syn-CH3C(O)OH acids with >110 kcal/mol exothermicities via loose roaming-like insertion TSs involving the terminal O atom and the neighboring C-H bonds. For syn-CH3C(H)OO, the major decomposition channel occurs by abstraction of a H atom from the CH3 group by the terminal O atom producing CH2C(H)O-OH. At 298 K, the intramolecular insertion process in CH2OO was found to be 600 times faster than the commonly assumed ring-closing reaction.
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- 2015
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24. MiR-29c mediates epithelial-to-mesenchymal transition in human colorectal carcinoma metastasis via PTP4A and GNA13 regulation of β-catenin signaling.
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Zhang JX, Mai SJ, Huang XX, Wang FW, Liao YJ, Lin MC, Kung HF, Zeng YX, and Xie D
- Subjects
- Cell Cycle Proteins genetics, Cell Line, Tumor, Cell Movement genetics, Colorectal Neoplasms pathology, Epithelial-Mesenchymal Transition genetics, Female, Gene Expression Regulation, Neoplastic, Glycogen Synthase Kinase 3 genetics, Glycogen Synthase Kinase 3 beta, Humans, Membrane Proteins genetics, Neoplasm Metastasis, Protein Tyrosine Phosphatases genetics, Wnt Signaling Pathway, Cell Cycle Proteins biosynthesis, Colorectal Neoplasms genetics, Membrane Proteins biosynthesis, MicroRNAs genetics, Protein Tyrosine Phosphatases biosynthesis, beta Catenin genetics
- Abstract
Background: Distant metastasis is the major cause of cancer-related death, and epithelial-to-mesenchymal transition (EMT) has a critical role in this process. Accumulating evidence indicates that EMT can be regulated by microRNAs (miRNAs). miR-29c has been implicated as a tumor suppressor in several human cancers. However, the role of miR-29c in the progression of colorectal cancer (CRC) metastasis remains largely unknown., Patients and Methods: The expression of miR-29c was examined by qRT-PCR in a cohort of primary CRC (PC) and distant liver metastasis (LM) tissues. A series of in vivo and in vitro assays were carried out in order to elucidate the functions of miR-29c and the molecular mechanisms underlying the pathogenesis of metastatic CRC., Results: miR-29c was markedly downregulated in PCs with distant metastasis and determined to be an independent predictor of shortened patient survival. But LM tissues showed higher levels of miR-29c than that in PC tissues. In CRC cells, miR-29c dramatically suppressed cell migration and invasion abilities in vitro and cancer metastasis in vivo. In addition, miR-29c inhibited EMT and negatively regulated Wnt/β-catenin signaling pathway. Guanine nucleotide binding protein alpha13 (GNA13) and protein tyrosine phosphatase type IVA (PTP4A) were identified as direct targets of miR-29c, which acted through ERK/GSK3β/β-catenin and AKT/GSK3β/β-catenin pathways, respectively, to regulate EMT. Furthermore, significant associations between miR-29c, its target genes (GNA13 and PTP4A) and EMT markers were validated in both PC and LM tissues., Conclusion: Our findings highlight the important role of miR-29c in regulating CRC EMT via GSK-3β/β-catenin signaling by targeting GNA13 and PTP4A and provide new insights into the metastatic basis of CRC., (© The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2014
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25. Reaction dynamics of O(¹D) + HCOOD/DCOOH investigated with time-resolved Fourier-transform infrared emission spectroscopy.
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Huang SC, Nghia NT, Putikam R, Nguyen HM, Lin MC, Tsuchiya S, and Lee YP
- Abstract
We investigated the reaction dynamics of O((1)D) towards hydrogen atoms of two types in HCOOH. The reaction was initiated on irradiation of a flowing mixture of O3 and HCOOD or DCOOH at 248 nm. The relative vibration-rotational populations of OH and OD (1 ≦ v ≦ 4, J ≤ 15) states were determined from time-resolved IR emission recorded with a step-scan Fourier-transform spectrometer. In the reaction of O((1)D) + HCOOD, the rotational distribution of product OH is nearly Boltzmann, whereas that of OD is bimodal. The product ratio [OH]/[OD] is 0.16 ± 0.05. In the reaction of O((1)D) + DCOOH, the rotational distribution of product OH is bimodal, but the observed OD lines are too weak to provide reliable intensities. The three observed OH/OD channels agree with three major channels of production predicted with quantum-chemical calculations. In the case of O((1)D) + HCOOD, two intermediates HOC(O)OD and HC(O)OOD are produced in the initial C-H and O-D insertion, respectively. The former undergoes further decomposition of the newly formed OH or the original OD, whereas the latter produces OD via direct decomposition. Decomposition of HOC(O)OD produced OH and OD with similar vibrational excitation, indicating efficient intramolecular vibrational relaxation, IVR. Decomposition of HC(O)OOD produced OD with greater rotational excitation. The predicted [OH]/[OD] ratio is 0.20 for O((1)D) + HCOOD and 4.08 for O((1)D) + DCOOH; the former agrees satisfactorily with experiments. We also observed the v3 emission from the product CO2. This emission band is deconvoluted into two components corresponding to internal energies E = 317 and 96 kJ mol(-1) of CO2, predicted to be produced via direct dehydration of HOC(O)OH and secondary decomposition of HC(O)O that was produced via decomposition of HC(O)OOH, respectively.
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- 2014
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26. Extremely rapid self-reaction of the simplest Criegee intermediate CH2OO and its implications in atmospheric chemistry.
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Su YT, Lin HY, Putikam R, Matsui H, Lin MC, and Lee YP
- Subjects
- Kinetics, Molecular Structure, Atmosphere, Formaldehyde chemistry, Models, Theoretical, Oxides chemistry
- Abstract
Criegee intermediates, which are carbonyl oxides produced when ozone reacts with unsaturated hydrocarbons, play an important role in the formation of OH and organic acids in the atmosphere, but they have eluded direct detection until recently. Reactions that involve Criegee intermediates are not understood fully because data based on their direct observation are limited. We used transient infrared absorption spectroscopy to probe directly the decay kinetics of formaldehyde oxide (CH2OO) and found that it reacts with itself extremely rapidly. This fast self-reaction is a result of its zwitterionic character. According to our quantum-chemical calculations, a cyclic dimeric intermediate that has the terminal O atom of one CH2OO bonded to the C atom of the other CH2OO is formed with large exothermicity before further decomposition to 2H2CO + O2((1)Δg). We suggest that the inclusion of this previously overlooked rapid reaction in models may affect the interpretation of previous laboratory experiments that involve Criegee intermediates.
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- 2014
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27. Detection of human JCPyV and BKPyV in diffuse large B-cell lymphoma of the GI tract.
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Tseng CE, Yeh CM, Fang CY, Shay J, Chen PL, Lin MC, Chang D, and Wang M
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- Aged, Aged, 80 and over, BK Virus classification, BK Virus genetics, DNA, Viral genetics, Female, Gastrointestinal Neoplasms chemistry, Humans, Immunohistochemistry, JC Virus classification, JC Virus genetics, Lymphoma, B-Cell chemistry, Male, Middle Aged, Gastrointestinal Neoplasms virology, Lymphoma, B-Cell virology, Polyomavirus Infections virology
- Abstract
Previous studies have demonstrated that infection with human polyomavirus, such as JCPyV and BKPyV, might be associated with various human tumors. However, an association between human JCPyV and BKPyV infection and diffuse large B-cell lymphoma (DLBCL) has not been reported. The purpose of this study was to examine DLBCLs of the gastrointestinal tract for evidence of human polyomavirus infection. Nested PCR and DNA sequencing were employed for viral DNA detection and viral genotype identification. In addition, two viral proteins, the large tumor antigen (LT) and the major structural protein (VP1), were detected by immunohistochemistry (IHC). Human JCPyV and BKPyV DNA was detected in 14 out of 16 tissue samples (87.5%), whereby nine cases were infected with JCPyV and five cases were infected with BKPyV. Both archetypal and rearranged genotypes of JCPyV and BKPyV were detected in the tissues. LT was detected in 11 tissue samples (68.75%). However, VP1 was not detected in any of the tissue samples. The presence of human JCPyV and BKPyV DNA and protein in DLBCL tissues of gastrointestinal tract were first reported in this study. The current results provide evidence of a possible association between human JCPyV and BKPyV infection and DLBCL.
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- 2014
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28. A nationwide population-based retrospective cohort study: increased risk of acute coronary syndrome in patients with ankylosing spondylitis.
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Chou CH, Lin MC, Peng CL, Wu YC, Sung FC, Kao CH, and Liu SH
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Case-Control Studies, Cohort Studies, Comorbidity, Diabetes Mellitus epidemiology, Female, Humans, Hypertension epidemiology, Incidence, Male, Middle Aged, Neoplasms epidemiology, Retrospective Studies, Risk Factors, Taiwan epidemiology, Young Adult, Acute Coronary Syndrome epidemiology, Cardiovascular Diseases epidemiology, Spondylitis, Ankylosing complications, Spondylitis, Ankylosing epidemiology
- Abstract
Objectives: To compare the risk of acute coronary syndrome (ACS) between patients with and without ankylosing spondylitis (AS)., Method: This retrospective cohort study identified all patients with AS aged ≥ 18 years newly diagnosed from 2000 to 2009, registered in the National Health Insurance Research Database (NHIRD) in Taiwan. The non-AS cohort consisted of fourfold randomly selected control patients free of AS, frequency matched by age, sex, and diagnosis year. The incidence of ACS was determined for both AS and non-AS cohorts., Results: We selected 6262 patients with AS and 25 048 patients without AS. The patients with AS were more prevalent than those without, with co-morbidities of hypertension, diabetes mellitus (DM), hyperlipidaemia, stroke, and peripheral vascular diseases. The overall incidence rate of ACS was higher in the AS cohort than in the non-AS cohort (4.4 vs. 2.9 per 1000 person-years), with an adjusted hazard ratio (aHR) of 1.36 [95% confidence interval (CI) 1.16-1.59]. AS patients with co-morbidities of hypertension, DM, and cancer had an aHR of 7.74 for ACS, compared to those without these co-morbidities., Conclusions: AS patients are at higher risk of ACS compared with non-AS subjects. Management of CV risk factors should be taken into account for the treatment of patients with AS, especially for patients with co-morbidities of hypertension, DM, and cancer.
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- 2014
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29. Ab initio chemical kinetics for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the related unimolecular decomposition of Si3H8 under a-Si/H CVD conditions.
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Raghunath P and Lin MC
- Abstract
The kinetics and mechanisms for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the related unimolecular decomposition of Si3H8 have been investigated by ab initio molecular orbital theory based on the QCISD(T)/CBS//QCISD/6-311++G(d,p) method in conjunction with quantum statistical variational Rice-Ramsperger-Kassel-Marcus (RRKM) calculations. For the barrierless radical association processes, their variational transition states have been characterized by the CASPT2//CASSCF method. The species involved in the study are known to coexist under CVD conditions. The results show that the association reaction of SiH2 and Si2H6 producing Si3H8 occurs by insertion via its lowest-energy path forming a loose hydrogen-bonding molecular complex with 8.3 kcal/mol binding energy; the reaction is exothermic by 55.0 kcal/mol. The chemically activated Si3H8 adduct can fragment by several paths, producing SiH4 + SiH3SiH (-0.7 kcal/mol), Si(SiH3)2 + H2 (-1.4 kcal/mol), and SiH3SiH2SiH + H2 (-1.4 kcal/mol). The predicted enthalpy changes as given agree well with available thermochemical data. Three other decomposition channels of Si3H8 occurring by Si-H or Si-Si breaking were found to be highly endothermic, and the reactions take place without a well-defined barrier. The heats of formation of Si3H8, SiH2SiH, Si2H4, i-Si3H7, n-Si3H7, Si(SiH3)2, and SiH3SiH2SiH have been predicted and found to be in close agreement with those available data in the literature. The product branching rate constants for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the thermal unimolecular decomposition of Si3H8 for all low-energy paths have been calculated with multichannel variational RRKM theory covering varying P,T conditions typically employed in PECVD and Cat-CVD processes for hydrogenated amorphous silicon (a-Si/H) film growth. The results were also found to be in good agreement with available kinetic data. Our kinetic results may be employed to model and control very large-area a-Si/H film growth for a new generation of solar cell applications.
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- 2013
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30. Effect of roaming transition states upon product branching in the thermal decomposition of CH3NO2.
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Zhu RS, Raghunath P, and Lin MC
- Abstract
The kinetics for the thermal unimolecular decomposition of CH3NO2 and its structural isomer CH3ONO have been investigated by statistical theory calculations based on the potential energy surface calculated at the UCCSD(T)/CBS and CASPT3(8, 8)/6-311+G(3df,2p) levels. Our results show that for the decomposition of CH3NO2 at pressures less than 2 Torr, isomerization to CH3ONO via the recently located roaming transition state is dominant in the entire temperature range studied, 400-3000 K. However, at higher pressures, the formation of the commonly assumed products, CH3 + NO2, becomes competitive and at pressures higher than 200 Torr the production of CH3 + NO2 is exclusive. The predicted rate constants for 760 Torr and the high-pressure limit with Ar as diluent in the temperature range 500-3000 K, producing solely CH3 + NO2, can be expressed respectively by kd(760)(CH3NO2) = 2.94 × 10(55)T(-12.6) exp(-35500/T) s(-1) and kd(∞)(CH3NO2) = 5.88 × 10(24)T(-2.35) exp(-31400/T) s(-1). In the low pressure limit, the decomposition reaction takes place exclusively via the roaming TS producing internally excited CH3ONO, giving rise to both CH3O + NO and CH2O + HNO with the second-order rate constant kd(0)(CH3NO2) = 1.17 × 10(31)T(-10.94) exp(-32400/T) cm(3) molecule(-1) s(-1). For CH3ONO decomposition, a new roaming transition state connecting to the CH2O + HNO products has been located, lying 6.8 kcal/mol below the well-known four-member ring tight transition state and 0.7 kcal/mol below CH3O + NO. The rate constants predicted by similar calculations give rise to the following expressions for the thermal decomposition of CH3ONO in He: kd(760)(CH3ONO) = 8.75 × 10(41)T(-8.97) exp(-22600/T) s(-1) and kd(∞)(CH3ONO) = 1.58 × 10(23)T(-2.18) exp(-21100/T) s(-1) in the temperature range 300-3000 K. These results are in very good agreement with available experimental data obtained under practical pressure conditions. The much different branching ratios for the formation of CH3O + NO and CH2O + HNO in the decomposition of both CH3NO2 and CH3ONO are also given in this work.
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- 2013
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31. Structure in the visible absorption bands of jet-cooled phenylperoxy radicals.
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Freel KA, Sullivan MN, Park J, Lin MC, and Heaven MC
- Abstract
The visible absorption bands of the phenylperoxy radical in the gas phase have been investigated using cavity ring-down spectroscopy. Jet-cooling was used to reduce the spectral congestion. Structured spectra spanning the range from 17,500 to 19,000 cm(-1) are reported for the first time. Analyses of these data have been guided by the results from time-dependent density functional calculations. The observed spectrum was found to be dominated by the bands of the B̃(2)A″-X̃(2)A″ transition. An analysis of the rotational contour for the origin band yielded a homogeneous line width of 2.2 cm(-1), corresponding to a decay rate of 4.1 × 10(11) s(-1). The results provide a rationale for the lack of structure in room temperature spectra that have been previously attributed to phenylperoxy. They also indicate that the lower energy region of the spectrum may show resolvable structure at room temperature. If so, this would provide a more definitive signature for monitoring phenylperoxy in kinetic measurements.
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- 2013
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32. Ab initio chemical kinetics for H + NCN: prediction of NCN heat of formation and reaction product branching via doublet and quartet surfaces.
- Author
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Teng WS, Moskaleva LV, Chen HL, and Lin MC
- Abstract
The reaction of NCN with H atoms has been investigated by ab initio MO and RRKM theory calculations. The mechanisms for formation of major products on the doublet and quartet potential energy surfaces have been predicted at the CCSD(T) level of theory with the complete basis set limit. In addition, the heat of formation for NCN predicted at this rigorous level and those from five isogyric reactions are in close agreement with the best value based on the isodesmic process, (3)CCO + N2 = (3)NCN + CO, 109.4 kcal/mol, which lies within the two existing experimental values. The rate constants for the three possible reaction channels, H + NCN → CH + N2 (k(P1)), HCN + (4)N (k(QP1)), and HNC + (4)N (k(QP2)), have been calculated in the temperature range 298-3000 K. The results show that k(P1) is significantly higher than k(QP1) and k(QP2) and that the total rate constant agrees well with available experimental values in the whole temperature range studied. The kinetics of the reverse CH + N2 reaction has also been revisited at the CCSD(T)/CBS level; the predicted total rate constants at 760 Torr Ar pressure can be represented by kr = 4.01 × 10(-15) T(0.90) exp(-17.42 kcal mol(-1)/RT) cm(3) molecule(-1) s(-1) at T = 800-4000 K. The result agrees closely with the most recent experimental data and the best theoretical result of Harding et al. (J. Phys. Chem. A 2008, 112, 522) as well as that of Moskaleva and Lin (Proc. Combust. Inst. 2000, 28, 2393) evaluated with a steady-state approximation after a coding error correction made in this study.
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- 2013
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33. Dental diagnostic X-ray exposure and risk of benign and malignant brain tumors.
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Lin MC, Lee CF, Lin CL, Wu YC, Wang HE, Chen CL, Sung FC, and Kao CH
- Subjects
- Adult, Female, Humans, Male, Middle Aged, Radiography, Dental trends, Risk Factors, Taiwan epidemiology, Young Adult, Brain Neoplasms diagnosis, Brain Neoplasms epidemiology, Neoplasms, Radiation-Induced diagnosis, Neoplasms, Radiation-Induced epidemiology, Population Surveillance methods, Radiography, Dental adverse effects
- Abstract
Background: This study evaluates the risk of benign brain tumors (BBTs) and malignant brain tumors (MBTs) associated with dental diagnostic X-ray, using a large population-based case-control study., Materials and Methods: We identified 4123 BBT cases and 16 492 controls without BBT (study 1) and 197 MBT cases and 788 controls without MBT (study 2) from Taiwan National Health Insurance claim data. The risks of both types of tumor were estimated in association with the frequency of received dental diagnostic X-ray., Results: The mean ages were ~44.2 years in study 1 and 40.6 years in study 2. Multivariable unconditional logistic regression analysis showed that the risk of BBT increases as the frequency of received dental diagnostic X-ray increases. The BBT odds ratio increased from 1.33 [95% confidence interval (CI) 1.22-1.44] for those with annual mean X-ray examination of less than one to 1.65 (95% CI 1.37-1.98) for those with three or more X-ray examinations, after controlling for comorbidities. No significant association was found between MBTs and dental diagnostic X-ray exposure., Conclusions: Exposure to dental diagnostic X-rays in oral and maxillofacial care increases the risk of BBTs, but not MBTs.
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- 2013
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34. Quantum chemical elucidation of the mechanism for hydrogenation of TiO2 anatase crystals.
- Author
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Raghunath P, Huang WF, and Lin MC
- Abstract
Hydrogenation of TiO2 is relevant to hydrogen storage and water splitting. We have carried out a detailed mechanistic study on TiO2 hydrogenation through H and∕or H2 diffusion from the surface into subsurface layers of anatase TiO2 (101) by periodic density functional theory calculations implementing on-site Coulomb interactions (DFT + U). Both H atoms and H2 molecules can migrate from the crystal surface into TiO2 near subsurface layer with 27.8 and 46.2 kcal∕mol energy barriers, respectively. The controlling step for the former process is the dissociative adsorption of H2 on the surface which requires 47.8 kcal∕mol of energy barrier. Both hydrogen incorporation processes are expected to be equally favorable. The barrier energy for H2 migration from the first layer of the subsurface Osub1 to the 2nd layer of the subsurface oxygen Osub2 requires only 6.6 kcal. The presence of H atoms on the surface and inside the subsurface layer tends to promote both H and H2 penetration into the subsurface layer by reducing their energy barriers, as well as to prevent the escape of the H2 from the cage by increasing its escaping barrier energy. The H2 molecule inside a cage can readily dissociate and form 2HO-species exothermically (ΔH = -31.0 kcal∕mol) with only 26.2 kcal∕mol barrier. The 2HO-species within the cage may further transform into H2O with a 22.0 kcal∕mol barrier and 19.3 kcal∕mol exothermicity relative to the caged H2 molecule. H2O formation following the breaking of Ti-O bonds within the cage may result in the formation of O-vacancies and surface disordering as observed experimentally under a high pressure and moderately high temperature condition. According to density of states analysis, the projected density of states of the interstitial H, H2, and H2O appear prominently within the TiO2 band gap; in addition, the former induces a shift of the band gap position notably towards the conduction band. The thermochemistry for formation of the most stable sub-surface species (2HO and H2O) has been predicted. These results satisfactorily account for the photo-catalytic activity enhancement observed experimentally by hydrogenation at high temperatures and high pressures.
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- 2013
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35. A population-based cohort study in Taiwan--use of insulin sensitizers can decrease cancer risk in diabetic patients?
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Kao CH, Sun LM, Chen PC, Lin MC, Liang JA, Muo CH, Chang SN, and Sung FC
- Subjects
- Aged, Cohort Studies, Female, Humans, Hypoglycemic Agents adverse effects, Insulin Resistance, Male, Middle Aged, Risk Factors, Taiwan, Thiazolidinediones adverse effects, Diabetes Mellitus drug therapy, Hypoglycemic Agents therapeutic use, Neoplasms epidemiology, Thiazolidinediones therapeutic use
- Abstract
Background: The purpose of the study was to explore the possible association between the use of insulin sensitizers (thiazolidinediones, TZDs) and the risk of cancer in Taiwanese diabetic patients., Patients and Methods: From the National Health Insurance Research Database (NHIRD) of Taiwan, we identified 22 910 diabetic patients newly diagnosed from 2001 to 2009 and 91 636 non-diabetic comparisons frequency matched with age, sex, and calendar year, excluding those with cancer at the baseline. Among the diabetics, 4159 patients were treated with TZDs and the rest of 18 752 patients were on other anti-diabetic medications (non-TZDs)., Results: In comparison to the non-diabetes group, the non-TZDs group had an increased risk of developing cancer [the adjusted hazard ratio (HR): 1.20 and 95% confidence interval (CI) = 1.11-1.30]. The TZDs group had a HR of 1.18 (95% CI = 0.98-1.42). Analysis of site-specific cancer risks showed that both TZDs and non-TZDs groups with elevated risks of colorectal and pancreatic cancer. However, the non-TZDs group had an increased risk of liver cancer when comparing with TZD and non-diabetes groups., Conclusion: This study suggests that patients with diabetes are at an elevated risk of cancer (especially in colorectal and pancreatic cancers), and the use of TZDs might decrease the liver cancer risk in diabetic patients. Further investigation using large samples and rigorous methodology is warranted.
- Published
- 2013
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36. Mechanism and kinetics for ammonium dinitramide (ADN) sublimation: a first-principles study.
- Author
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Zhu RS, Chen HL, and Lin MC
- Subjects
- Kinetics, Water chemistry, Nitrites chemistry, Quantum Theory, Quaternary Ammonium Compounds chemistry
- Abstract
The mechanism for sublimation of NH(4)N(NO(2))(2) (ADN) has been investigated quantum-mechanically with generalized gradient approximation plane-wave density functional theory calculations; the solid surface is represented by a slab model and the periodic boundary conditions are applied. The calculated lattice constants for the bulk ADN, which were found to consist of NH(4)(+)[ON(O)NNO(2)](-) units, instead of NH(4)(+)[N(NO(2))(2)](-), agree quite well with experimental values. Results show that three steps are involved in the sublimation/decomposition of ADN. The first step is the relaxation of the surface layer with 1.6 kcal/mol energy per NH(4)ON(O)NNO(2) unit; the second step is the sublimation of the surface layer to form a molecular [NH(3)]-[HON(O)NNO(2)] complex with a 29.4 kcal/mol sublimation energy, consistent with the experimental observation of Korobeinichev et al. (10) The last step is the dissociation of the [H(3)N]-[HON(O)NNO(2)] complex to give NH(3) and HON(O)NNO(2) with the dissociation energy of 13.9 kcal/mol. Direct formation of NO(2) (g) from solid ADN costs a much higher energy, 58.3 kcal/mol. Our calculated total sublimation enthalpy for ADN(s) → NH(3)(g) + HON(O)NNO(2)) (g), 44.9 kcal/mol via three steps, is in good agreement with the value, 42.1 kcal/mol predicted for the one-step sublimation process in this work and the value 44.0 kcal/mol computed by Politzer et al. (11) using experimental thermochemical data. The sublimation rate constant for the rate-controlling step 2 can be represented as k(sub) = 2.18 × 10(12) exp (-30.5 kcal/mol/RT) s(-1), which agrees well with available experimental data within the temperature range studied. The high pressure limit decomposition rate constant for the molecular complex H(3)N···HON(O)NNO(2) can be expressed by k(dec) = 3.18 × 10(13) exp (-15.09 kcal/mol/RT) s(-1). In addition, water molecules were found to increase the sublimation enthalpy of ADN, contrary to that found in the ammonium perchlorate system, in which water molecules were shown to reduce pronouncedly the enthalpy of sublimation.
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- 2012
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37. Effects of [123I]ADAM, a serotonin transporter radiopharmaceutical, on pregnant Sprague-Dawley rats.
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Chang KW, Lin MC, Lee SY, Chen HY, Chen CC, and Fu YK
- Subjects
- Animals, Cinanserin toxicity, Female, Fertility drug effects, Fertility radiation effects, Iodine Radioisotopes, Pregnancy, Radiopharmaceuticals toxicity, Rats, Rats, Sprague-Dawley, Serotonin Plasma Membrane Transport Proteins pharmacology, Cinanserin analogs & derivatives, Pregnancy, Animal radiation effects, Serotonin Plasma Membrane Transport Proteins radiation effects
- Abstract
Serotonin transport abnormalities are implicated in neuropsychiatric disorders. [(123)I]ADAM ([(123)I]-2-([2-({dimethylamino}methyl)phenyl]thio)-5-iodophenylamine) is a novel radiotracer that targets serotonin transporters. We assessed the toxicity of [(123)I]ADAM (18.5 MBq) administered in early- and late-phases (8 and 14 day postfertilization, respectively) of pregnancy. The mortality, clinical status, and gross necropsy were measured in pregnant rats, and the fertility index was measured in rat offspring (weight, clinical observations). We found no dosing-related clinical signs. In conclusion, [(123)I]ADAM was not toxic in an animal pregnancy model., (Copyright © 2012. Published by Elsevier Ltd.)
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- 2012
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38. Dynamics of the reactions of O(1D) with CD3OH and CH3OD studied with time-resolved Fourier-transform IR spectroscopy.
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Huang CK, Xu ZF, Nakajima M, Nguyen HM, Lin MC, Tsuchiya S, and Lee YP
- Abstract
We investigated the reactivity of O((1)D) towards two types of hydrogen atoms in CH(3)OH. The reaction was initiated on irradiation of a flowing mixture of O(3) and CD(3)OH or CH(3)OD at 248 nm. Relative vibration-rotational populations of OH and OD (1 ≤ v ≤ 4) states were determined from their infrared emission recorded with a step-scan time-resolved Fourier-transform spectrometer. In O((1)D) + CD(3)OH, the rotational distribution of OD is nearly Boltzmann, whereas that of OH is bimodal; the product ratio [OH]/[OD] is 1.56 ± 0.36. In O((1)D) + CH(3)OD, the rotational distribution of OH is nearly Boltzmann, whereas that of OD is bimodal; the product ratio [OH]/[OD] is 0.59 ± 0.14. Quantum-chemical calculations of the potential energy and microcanonical rate coefficients of various channels indicate that the abstraction channels are unimportant and O((1)D) inserts into the C-H and O-H bonds of CH(3)OH to form HOCH(2)OH and CH(3)OOH, respectively. The observed three channels of OH are consistent with those produced via decomposition of the newly formed OH or the original OH moiety in HOCH(2)OH or decomposition of CH(3)OOH. The former decomposition channel of HOCH(2)OH produces vibrationally more excited OH because of incomplete intramolecular vibrational relaxation, and decomposition of CH(3)COOH produces OH with greater rotational excitation, likely due to a large torque angle during dissociation. The predicted [OH]/[OD] ratios are 1.31 and 0.61 for O((1)D) + CD(3)OH and CH(3)OD, respectively, at collision energy of 26 kJ mol(-1), in satisfactory agreement with the experimental results. These predicted product ratios vary weakly with collision energy.
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- 2012
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39. HGFK1 inhibits bone metastasis in breast cancer through the TAK1/p38 MAPK signaling pathway.
- Author
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Yao Y, Fang ZP, Chen H, Yue L, Min DL, Tang LN, Yu WX, Kung HF, Lin MC, and Shen Z
- Subjects
- Adult, Aged, Animals, Bone Neoplasms secondary, Breast Neoplasms pathology, Cell Line, Tumor, Cell Movement, Dependovirus genetics, Dependovirus metabolism, Drug Screening Assays, Antitumor, Enzyme Activation, Female, Gene Expression Regulation, Neoplastic, Genes, Tumor Suppressor, Genetic Therapy methods, Genetic Vectors genetics, Genetic Vectors metabolism, Hepatocyte Growth Factor administration & dosage, Hepatocyte Growth Factor genetics, Humans, Imidazoles pharmacology, Intracellular Signaling Peptides and Proteins genetics, Intracellular Signaling Peptides and Proteins metabolism, Kringles, MAP Kinase Kinase Kinases genetics, Mice, Mice, Inbred BALB C, Middle Aged, Phosphorylation, Prognosis, Protein Serine-Threonine Kinases genetics, Protein Serine-Threonine Kinases metabolism, Pyridines pharmacology, Real-Time Polymerase Chain Reaction methods, Receptor Activator of Nuclear Factor-kappa B genetics, Receptor Activator of Nuclear Factor-kappa B metabolism, p38 Mitogen-Activated Protein Kinases antagonists & inhibitors, p38 Mitogen-Activated Protein Kinases genetics, p38 Mitogen-Activated Protein Kinases metabolism, Bone Neoplasms therapy, Breast Neoplasms therapy, Hepatocyte Growth Factor metabolism, MAP Kinase Kinase Kinases metabolism, MAP Kinase Signaling System
- Abstract
Breast cancer metastasis to bone represents a devastating complication of advanced breast cancer, frequently resulting in significant increases in morbidity and mortality. An understanding of the mechanisms that govern breast cancer metastasis at the molecular level should lead to more effective therapies. Recently, the kringle 1 domain of human hepatocyte growth factor (HGFK1) was identified as a candidate metastasis suppressor gene. Here, we investigated whether HGFK1 is a key regulator of breast cancer bone metastasis. Of the 193 human breast carcinoma tissue samples examined, HGFK1 expression was relative higher in 82 (42.4%) by western blot and in 84 (43.5%) by quantitative real-time PCR. The higher expression of HGFK1 was significantly associated with a better prognostic value (P<0.001) and inversely correlated with bone metastasis (P=0.003). The efficacy of adeno-associated virus carrying HGFK1 (AAV-HGFK1) in osteolytic bone metastasis was then evaluated using an in vivo bone metastasis model. AAV-HGFK1 significantly inhibited osteolytic bone metastasis and prolonged the survival of mice in this model (P<0.01). In vitro, HGFK1 expression resulted in significant anti-invasion effects, enhanced the phosphorylation of TAK1 (transforming growth factor-β-activated kinase 1), p38 MAPK (mitogen-activated protein kinase) and MAPKAPK2 (MAPK-activated protein kinase 2) and decreased the expression of receptor activator of nuclear factor-κB (RANK), which was abrogated by the p38 MAPK inhibitor SB203580. This study shows for the first time that HGFK1 significantly inhibits the metastasis of breast cancer to bone by activating the TAK1/p38 MAPK signaling pathway and inhibiting RANK expression. Thus, AAV-HGFK1 treatment represents a potential therapy for bone metastasis in breast cancer.
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- 2012
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40. Auditing consistency and usefulness of LOINC use among three large institutions - using version spaces for grouping LOINC codes.
- Author
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Lin MC, Vreeman DJ, McDonald CJ, and Huff SM
- Subjects
- Clinical Audit, Clinical Coding methods, Databases, Factual, Diagnostic Techniques and Procedures classification, Evaluation Studies as Topic, Hospitals, Humans, Medical Informatics methods, Clinical Coding standards, Logical Observation Identifiers Names and Codes, Medical Informatics standards
- Abstract
Objectives: We wanted to develop a method for evaluating the consistency and usefulness of LOINC code use across different institutions, and to evaluate the degree of interoperability that can be attained when using LOINC codes for laboratory data exchange. Our specific goals were to: (1) Determine if any contradictory knowledge exists in LOINC. (2) Determine how many LOINC codes were used in a truly interoperable fashion between systems. (3) Provide suggestions for improving the semantic interoperability of LOINC., Methods: We collected Extensional Definitions (EDs) of LOINC usage from three institutions. The version space approach was used to divide LOINC codes into small sets, which made auditing of LOINC use across the institutions feasible. We then compared pairings of LOINC codes from the three institutions for consistency and usefulness., Results: The number of LOINC codes evaluated were 1917, 1267 and 1693 as obtained from ARUP, Intermountain and Regenstrief respectively. There were 2022, 2030, and 2301 version spaces among ARUP and Intermountain, Intermountain and Regenstrief and ARUP and Regenstrief respectively. Using the EDs as the gold standard, there were 104, 109 and 112 pairs containing contradictory knowledge and there were 1165, 765 and 1121 semantically interoperable pairs. The interoperable pairs were classified into three levels: (1) Level I - No loss of meaning, complete information was exchanged by identical codes. (2) Level II - No loss of meaning, but processing of data was needed to make the data completely comparable. (3) Level III - Some loss of meaning. For example, tests with a specific 'method' could be rolled-up with tests that were 'methodless'., Conclusions: There are variations in the way LOINC is used for data exchange that result in some data not being truly interoperable across different enterprises. To improve its semantic interoperability, we need to detect and correct any contradictory knowledge within LOINC and add computable relationships that can be used for making reliable inferences about the data. The LOINC committee should also provide detailed guidance on best practices for mapping from local codes to LOINC codes and for using LOINC codes in data exchange., (Copyright © 2012 Elsevier Inc. All rights reserved.)
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- 2012
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41. The clinical differences between dengue and scrub typhus with acute respiratory failure in southern Taiwan.
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Chang HC, Lin MC, Liu SF, Su MC, Fang WF, Chen YC, Tseng CC, Lai CH, Huang KT, and Wang CC
- Subjects
- Acute Disease, Adult, Aged, Dengue epidemiology, Female, Humans, Male, Middle Aged, Respiratory Distress Syndrome etiology, Respiratory Insufficiency epidemiology, Retrospective Studies, Scrub Typhus epidemiology, Taiwan epidemiology, Dengue complications, Respiratory Insufficiency etiology, Scrub Typhus complications
- Abstract
Background: For both dengue and scrub typhus, acute respiratory failure (ARF) is a serious complication. The present study was carried out in order to investigate the clinical courses and outcomes of adult dengue and scrub typhus patients with ARF, and to identify the clinical differences between adult dengue and scrub typhus patients with ARF., Methods: We conducted a retrospective study of the serologically confirmed adult dengue or scrub typhus patients admitted between 1998 and 2008 at Kaohsiung Chang Gung Memorial Hospital. A total of 980 dengue and 102 scrub typhus adult patients were included in our study., Results: Eighteen of the 980 adult dengue patients and 8 of the 102 adult scrub typhus patients had ARF. There were significant differences that existed for eschar (P = 0.001; dengue 0%; scrub 62.5%), cough (P = 0.016; dengue 55.6%; scrub typhus 100%), white blood cell (WBC) count [P = 0.026; dengue 7.40 ± 5.74; scrub typhus 11.84 ± 4.95 (×10(3)/μL)], platelet count [P = 0.008; dengue 42.2 ± 33.9; scrub typhus 104.1 ± 93.3 (×10(9)/L)], prothrombin time (PT) [P = 0.007; dengue 12.82 ± 1.36; scrub typhus 10.74 ± 0.98 (s)], activated partial thromboplastin time (APTT) [P = 0.002; dengue 50.81 ± 10.08; scrub typhus 37.44 ± 4.06 (s)], blood urea nitrogen (BUN) [P < 0.001; dengue 64.6 ± 43.2; scrub typhus 20.9 ± 9.1 (mg/dL)], creatinine [P < 0.001; dengue 3.77 ± 3.37; scrub typhus 1.05 ± 0.37 (mg/dL)], admission day (A-day) [P = 0.027; dengue 2.9 ± 1.3; scrub typhus 5.4 ± 2.6 (days)], and ventilator duration [P = 0.022; dengue 9.4 ± 14.0; scrub typhus 14.8 ± 10.4 (days)] between both groups., Conclusions: This study provides relatively rare data regarding the clinical differences between adult dengue and scrub typhus patients with ARF.
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- 2012
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42. Ab initio chemical kinetics for the ClOO + NO reaction: effects of temperature and pressure on product branching formation.
- Author
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Raghunath P and Lin MC
- Abstract
The kinetics and mechanism for the reaction of ClOO with NO have been investigated by ab initio molecular orbital theory calculations based on the CCSD(T)/6-311+G(3df)//PW91PW91∕6-311+G(3df) method, employed to evaluate the energetics for the construction of potential energy surfaces and prediction of reaction rate constants. The results show that the reaction can produce two key low energy products ClNO + (3)O(2) via the direct triplet abstraction path and ClO + NO(2) via the association and decomposition mechanism through long-lived singlet pc-ClOONO and ClONO(2) intermediates. The yield of ClNO + O(2) ((1)△) from any of the singlet intermediates was found to be negligible because of their high barriers and tight transition states. As both key reactions initially occur barrierlessly, their rate constants were evaluated with a canonical variational approach in our transition state theory and Rice-Ramspergen-Kassel-Marcus/master equation calculations. The rate constants for ClNO + (3)O(2) and ClO + NO(2) production from ClOO + NO can be given by 2.66 × 10(-16) T(1.91) exp(341/T) (200-700 K) and 1.48 × 10(-24) T(3.99) exp(1711/T) (200-600 K), respectively, independent of pressure below atmospheric pressure. The predicted total rate constant and the yields of ClNO and NO(2) in the temperature range of 200-700 K at 10-760 Torr pressure are in close agreement with available experimental results.
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- 2012
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43. Ab initio chemical kinetics for the hydrolysis of N2O4 isomers in the gas phase.
- Author
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Zhu RS, Lai KY, and Lin MC
- Abstract
The mechanism and kinetics for the gas-phase hydrolysis of N(2)O(4) isomers have been investigated at the CCSD(T)/6-311++G(3df,2p)//B3LYP/6-311++G(3df,2p) level of theory in conjunction with statistical rate constant calculations. Calculated results show that the contribution from the commonly assumed redox reaction of sym-N(2)O(4) to the homogeneous gas-phase hydrolysis of NO(2) can be unequivocally ruled out due to the high barrier (37.6 kcal/mol) involved; instead, t-ONONO(2) directly formed by the association of 2NO(2), was found to play the key role in the hydrolysis process. The kinetics for the hydrolysis reaction, 2NO(2) + H(2)O ↔ HONO + HNO(3) (A) can be quatitatively interpreted by the two step mechanism: 2NO(2) → t-ONONO(2), t-ONONO(2) + H(2)O → HONO + HNO(3). The predicted total forward and reverse rate constants for reaction (A), k(tf) = 5.36 × 10(-50)T(3.95) exp(1825/T) cm(6) molecule(-2) s(-1) and k(tr) = 3.31 × 10(-19)T(2.478) exp(-3199/T) cm(3) molecule(-1) s(-1), respectively, in the temperature range 200-2500 K, are in good agreement with the available experimental data.
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- 2012
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44. Kinetics and mechanisms for the adsorption, dissociation, and diffusion of hydrogen in Ni and Ni/YSZ slabs: a DFT study.
- Author
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Weng MH, Chen HT, Wang YC, Ju SP, Chang JG, and Lin MC
- Abstract
The adsorption, dissociation, and diffusion of hydrogen in Ni(100) and Ni(100)/YSZ(100) slabs with two different interfaces (Ni/cation and Ni/O interface) have been studied by the density functional theory (DFT) with the Perdew-Wang functional. The H(2) molecule is found to preferentially absorb on a Top (T) site with side-on configuration on the Ni(100) surface, while the H-atom is strongly bound at a fcc Hollow (H) site. The barrier for the H(2) dissociation on both surfaces is calculated to be only ~0.1 eV. The potential energy pathways of H diffusion on pure Ni and Ni/YSZ with the two different interfaces are studied. Our calculated results show that the H-atom diffusion occurs via surface path rather than the bulk path. For the bulk path in Ni/YSZ, H-atom migration can occur more readily at the Ni/cation interface compared to the Ni/O interface. The existence of vacancy in the interface region is found to improve the mobility of H-atoms at the interface of Ni/YSZ slab. The rate constants for hydrogen dissociation and diffusion in pure Ni and Ni/YSZ are predicted.
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- 2012
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45. Magnetic field enhanced resonant tunneling in a silicon nanowire single-electron-transistor.
- Author
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Aravind K, Lin MC, Ho IL, Wu CS, Kuo W, Kuan CH, Chang-Liao KS, and Chen CD
- Abstract
We report fabrication, measurement and simulation of silicon single-electron-transistors made on silicon-on-insulator wafers. At T-2 K, these devices showed clear Coulomb blockade structures. An external perpendicular magnetic field was found to enhance the resonant tunneling peak and was used to predict the presence of two laterally coupled quantum dots in the narrow constriction between the source-drain electrodes. The proposed model and measured experimental data were consistently explained using numerical simulations.
- Published
- 2012
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46. EZH2 supports nasopharyngeal carcinoma cell aggressiveness by forming a co-repressor complex with HDAC1/HDAC2 and Snail to inhibit E-cadherin.
- Author
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Tong ZT, Cai MY, Wang XG, Kong LL, Mai SJ, Liu YH, Zhang HB, Liao YJ, Zheng F, Zhu W, Liu TH, Bian XW, Guan XY, Lin MC, Zeng MS, Zeng YX, Kung HF, and Xie D
- Subjects
- Adult, Animals, Base Sequence, Cell Line, Tumor, DNA-Binding Proteins genetics, Enhancer of Zeste Homolog 2 Protein, Female, Gene Expression Regulation, Neoplastic, Histone Deacetylase 1 genetics, Histone Deacetylase 2 genetics, Humans, Male, Mice, Mice, Inbred BALB C, Mice, Nude, Middle Aged, Molecular Sequence Data, Multiprotein Complexes metabolism, Nasopharyngeal Neoplasms genetics, Nasopharyngeal Neoplasms pathology, Neoplasm Invasiveness, Neoplasm Metastasis, Polycomb Repressive Complex 2, Promoter Regions, Genetic genetics, Protein Binding, RNA Interference, Repressor Proteins metabolism, Snail Family Transcription Factors, Transcription Factors genetics, Cadherins genetics, DNA-Binding Proteins metabolism, Histone Deacetylase 1 metabolism, Histone Deacetylase 2 metabolism, Nasopharyngeal Neoplasms metabolism, Transcription Factors metabolism
- Abstract
The enhancer of zeste homolog 2 (EZH2) is upregulated and has an oncogenic role in several types of human cancer. However, the abnormalities of EZH2 and its underlying mechanisms in the pathogenesis of nasopharyngeal carcinoma (NPC) remain unknown. In this study, we found that high expression of EZH2 in NPC was associated closely with an aggressive and/or poor prognostic phenotype (P<0.05). In NPC cell lines, knockdown of EZH2 by short hairpin RNA was sufficient to inhibit cell invasiveness/metastasis both in vitro and in vivo, whereas ectopic overexpression of EZH2 supported NPC cell invasive capacity with a decreased expression of E-cadherin. In addition, ablation of endogenous Snail in NPC cells virtually totally prevented the repressive activity of EZH2 to E-cadherin, indicating that Snail might be a predominant mediator of EZH2 to suppress E-cadherin. Furthermore, co-immunoprecipitation (IP), chromatin IP and luciferase reporter assays demonstrated that in NPC cells, (1) EZH2 interacted with HDAC1/HDAC2 and Snail to form a repressive complex; (2) these components interact in a linear fashion, not in a triangular fashion, that is, HDAC1 or HDAC2 bridge the interaction between EZH2 and Snail; and (3) the EZH2/HDAC1/2/Snail complex could closely bind to the E-cadherin promoter by Snail, but not YY1, to repress E-cadherin. The data provided in this report suggest a critical role of EZH2 in the control of cell invasion and/or metastasis by forming a co-repressor complex with HDAC1/HDAC2/Snail to repress E-cadherin, an activity that might be responsible, at least in part, for the development and/or progression of human NPCs.
- Published
- 2012
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47. Anthracyclines disrupt telomere maintenance by telomerase through inducing PinX1 ubiquitination and degradation.
- Author
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Zhang B, Qian D, Ma HH, Jin R, Yang PX, Cai MY, Liu YH, Liao YJ, Deng HX, Mai SJ, Zhang H, Zeng YX, Lin MC, Kung HF, Xie D, and Huang JJ
- Subjects
- Cell Cycle Proteins, Cell Line, Tumor, DNA Damage, Humans, Proteasome Endopeptidase Complex physiology, Anthracyclines pharmacology, Telomerase physiology, Telomere drug effects, Tumor Suppressor Proteins metabolism, Ubiquitination
- Abstract
Telomere maintenance is essential for cancer growth. Induction of telomere dysfunction, for example, by inhibition of telomeric proteins or telomerase, has been shown to strongly enhance cancer cells' sensitivity to chemotherapies. However, it is not clear whether modulations of telomere maintenance constitute cancer cellular responses to chemotherapies. Furthermore, the manner in which anti-cancer drugs affect telomere function remains unknown. In this study, we show that anthracyclines, a class of anti-cancer drugs widely used in clinical cancer treatments, have an active role in triggering telomere dysfunction specifically in telomerase-positive cancer cells. Anthracyclines interrupt telomere maintenance by telomerase through the downregulation of PinX1, a protein factor responsible for targeting telomerase onto telomeres, thereby inhibiting telomerase association with telomeres. We further demonstrate that anthracyclines downregulate PinX1 by inducing this protein degradation through the ubiquitin-proteasome-dependent pathway. Our data not only reveal a novel action for anthracyclines as telomerase functional inhibitors but also provide a clue for the development of novel anti-cancer drugs based on telomerase/telomere targeting, which is actively investigated by many current studies.
- Published
- 2012
- Full Text
- View/download PDF
48. Roaming-mediated isomerization in the photodissociation of nitrobenzene.
- Author
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Hause ML, Herath N, Zhu R, Lin MC, and Suits AG
- Subjects
- Isomerism, Nitric Oxide chemistry, Photochemistry, Nitrobenzenes chemistry
- Abstract
Roaming reactions comprise a new class of reaction in which a molecule undergoes frustrated dissociation to radicals, followed by an intramolecular abstraction reaction. Nitro compounds have long been known to dissociate to give NO as a major product. However, rates based upon isomerization via calculated tight transition states are implausibly slow, so the key dissociation pathway for this important class of molecules remains obscure. Here, we present an imaging study of the photodissociation of nitrobenzene with state-specific detection of the resulting NO products. We observe a bimodal translational energy distribution in which the slow products are formed with low NO rotational excitation, and the fast component is associated with high rotational excitation. High-level ab initio calculations identified a 'roaming-type' saddle point on the ground state. Branching ratio calculations then show that thermal dissociation of nitrobenzene is dominated by 'roaming-mediated isomerization' to phenyl nitrite, which subsequently decomposes to give C(6)H(5)O + NO.
- Published
- 2011
- Full Text
- View/download PDF
49. Photodissociation dynamics of benzaldehyde (C6H5CHO) at 266, 248, and 193 nm.
- Author
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Bagchi A, Huang YH, Xu ZF, Raghunath P, Lee YT, Ni CK, Lin MC, and Lee YP
- Abstract
The photodissociation of gaseous benzaldehyde (C(6)H(5)CHO) at 193, 248, and 266 nm using multimass ion imaging and step-scan time-resolved Fourier-transform infrared emission techniques is investigated. We also characterize the potential energies with the CCSD(T)/6-311+G(3df,2p) method and predict the branching ratios for various channels of dissociation. Upon photolysis at 248 and 266 nm, two major channels for formation of HCO and CO, with relative branching of 0.37:0.63 and 0.20:0.80, respectively, are observed. The C(6)H(5)+HCO channel has two components with large and small recoil velocities; the rapid component with average translational energy of approximately 25 kJ mol(-1) dominates. The C(6)H(6)+CO channel has a similar distribution of translational energy for these two components. IR emission from internally excited C(6)H(5)CHO, ν(3) (v=1) of HCO, and levels v≤2, J≤43 of CO are observed; the latter has an average rotational energy of approximately 13 kJ mol(-1) and vibrational energy of approximately 6 kJ mol(-1). Upon photolysis at 193 nm, similar distributions of energy are observed, except that the C(6)H(5)+HCO channel becomes the only major channel with a branching ratio of 0.82±0.10 and an increased proportion of the slow component; IR emission from levels ν(1) (v=1) and ν(3) (v=1 and 2) of HCO and v≤2, J≤43 of CO are observed; the latter has an average energy similar to that observed in photolysis at 248 nm. The observed product yields at different dissociation energies are compared to statistical-theory predicted results based on the computed singlet and triplet potential-energy surfaces., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2011
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50. The polymorphisms of C-reactive protein gene modify the association between central obesity and lung function in taiwan asthmatics.
- Author
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Wang TN, Wu CC, Huang MS, Wang CC, Huang CC, Wang TH, Lien TC, Ko YC, and Lin MC
- Subjects
- Adult, Aged, Asthma diagnosis, Asthma physiopathology, C-Reactive Protein genetics, DNA Mutational Analysis, Female, Genetic Association Studies, Genetic Predisposition to Disease, Genotype, Humans, Male, Middle Aged, Obesity, Abdominal diagnosis, Obesity, Abdominal physiopathology, Polymorphism, Genetic, Respiratory Function Tests, Taiwan, Waist-Hip Ratio, Asthma epidemiology, Asthma genetics, C-Reactive Protein metabolism, Obesity, Abdominal epidemiology, Obesity, Abdominal genetics
- Abstract
High-sensitivity C-reactive protein (hs-CRP) concentrations and obesity are proposed to have a significant relationship with impairment of lung function, but little has been reported to date on the association between CRP gene and lung function. We studied the association of three tagSNPs (tag single nucleotide polymorphisms) of CRP gene and their interactions with central obesity on lung function. A total of 384 asthmatic adults and 384 controls who were 1:1 matched by sex and age were recruited for this study. Three tagSNPs polymorphisms for CRP rs1417938, rs1800947 and rs1205 were selected from HapMap data and genotyping by using TaqMan allelic discrimination assay. A questionnaire interview, body composition and pulmonary function tests were performed. CRP single nucleotide polymorphisms (SNPs) did not increase the risk of asthma, but CRP rs1205 CC genotype significantly decreased the predictive value of forced vital capacity (FVC) in the asthma group (adjusted mean change = -7.54%, 95% CI = -13.82 to -1.25%). Waist-to-hip ratio, not body mass index, also decreased the predictive value of FVC in asthmatics. The subjects with central obesity who carried CRP SNPs have a significant reduction effect in lung function. The current results suggest that central obesity may play a major role in lung function, and these effects were modified significantly by the polymorphisms for CRP gene., (© 2011 The Authors. Scandinavian Journal of Immunology © 2011 Blackwell Publishing Ltd.)
- Published
- 2011
- Full Text
- View/download PDF
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