355 results on '"Pei, T."'
Search Results
2. A coherent nanomechanical oscillator driven by single-electron tunnelling
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Wen, Yutian, Ares, N., Schupp, F. J., Pei, T., Briggs, G. A. D., and Laird, E. A.
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Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
A single-electron transistor incorporated as part of a nanomechanical resonator represents an extreme limit of electron-phonon coupling. While it allows for fast and sensitive electromechanical measurements, it also introduces backaction forces from electron tunnelling which randomly perturb the mechanical state. Despite the stochastic nature of this backaction, under conditions of strong coupling it is predicted to create self-sustaining coherent mechanical oscillations. Here, we verify this prediction using time-resolved measurements of a vibrating carbon nanotube transistor. This electromechanical oscillator has intriguing similarities with a laser. The single-electron transistor, pumped by an electrical bias, acts as a gain medium while the resonator acts as a phonon cavity. Despite the unconventional operating principle, which does not involve stimulated emission, we confirm that the output is coherent, and demonstrate other laser behaviour including injection locking and frequency narrowing through feedback., Comment: 16 pages, 12 figures, 9 MB
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- 2019
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3. The use of hydrophobic amino acids in protecting spray dried trehalose formulations against moisture-induced changes
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Mah, Pei T, O'Connell, Peter, Focaroli, Stefano, Lundy, Ross, O'Mahony, Tom F, Hastedt, Jayne E, Gitlin, Irina, Oscarson, Stefan, Fahy, John V, and Healy, Anne Marie
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Pharmacology and Pharmaceutical Sciences ,Biomedical and Clinical Sciences ,Administration ,Inhalation ,Aerosols ,Amino Acids ,Chemistry ,Pharmaceutical ,Drug Compounding ,Dry Powder Inhalers ,Humidity ,Hydrophobic and Hydrophilic Interactions ,Leucine ,Powders ,Trehalose ,Wettability ,Aerosolization ,Hygroscopic ,L-leucine ,L-isoleucine ,Moisture protection ,Recrystallization ,Spray drying ,Pharmacology & Pharmacy ,Pharmacology and pharmaceutical sciences - Abstract
Trehalose is commonly used as a protein stabilizer in spray dried protein formulations delivered via the pulmonary route. Spray dried trehalose formulations are highly hygroscopic, which makes them prone to deliquescence and recrystallization when exposed to moisture, leading to impairment in aerosolization performance. The main aim of this study was to investigate and compare the effect of hydrophobic amino acids (i.e. L-leucine and L-isoleucine) in enhancing aerosolization performance and in mitigating moisture-induced changes in spray dried trehalose formulations. Trehalose was spray dried with 20-60% w/w of amino acid (i.e. L-leucine or L-isoleucine). The spray dried formulations were stored at 25 °C/50% RH for 28 days. Solid state characterization and in vitro aerosolization performance studies were performed on the spray dried formulations before and after storage. The addition of 20-60% w/w of amino acid (i.e. L-leucine or L-isoleucine) improved the emitted fractions of spray dried trehalose formulations from a dry powder inhaler. However, ≥ 40% w/w of L-leucine/L-isoleucine was needed to prevent recrystallization of trehalose in the formulations when exposed to 25 °C/50% RH for 28 days. X-ray photoelectron spectroscopy (XPS) demonstrated that samples with 40-60% w/w L-isoleucine had more amino acid on the surfaces of the particles compared to their L-leucine counterparts. This may explain the greater ability of the L-isoleucine (40-60% w/w) samples to cope with elevated humidity compared to L-leucine samples of the same concentrations, as observed in the dynamic vapour sorption (DVS) studies. In conclusion, this study demonstrated that both L-leucine and L-isoleucine were effective in enhancing aerosolization performance and mitigating moisture-induced reduction in aerosolization performance in spray dried trehalose formulations. L-isoleucine proved to be superior to L-leucine in terms of its moisture protectant effect when incorporated at the same concentration in the formulations.
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- 2019
4. Measuring carbon nanotube vibrations using a single-electron transistor as a fast linear amplifier
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Wen, Yutian, Ares, N., Pei, T., Briggs, G. A. D., and Laird, E. A.
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Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We demonstrate sensitive and fast electrical measurements of a carbon nanotube mechanical resonator. The nanotube is configured as a single-electron transistor, whose conductance is a sensitive transducer for its own displacement. Using an impedance-matching circuit followed by a cryogenic amplifier, the vibrations can be monitored in real time. The sensitivity of this continuous displacement measurement approaches within a factor 470 of the standard quantum limit., Comment: 10 pages, 6 figures; Published version
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- 2018
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5. Consistency of Continuous Ambulatory Interstitial Glucose Monitoring Sensors
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Wu, Pei T, Segovia, David E, Lee, Cathy C, and Nguyen, Kim-Lien
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Analytical Chemistry ,Biochemistry and Cell Biology ,Chemical Sciences ,Biological Sciences ,Diabetes ,Adolescent ,Adult ,Female ,Glucose ,Humans ,Male ,Middle Aged ,Monitoring ,Ambulatory ,Young Adult ,continuous glucose monitoring ,interstitial glucose sensors ,intra-subject agreement ,postprandial glucose ,Biochemistry and cell biology ,Analytical chemistry - Abstract
AimsThe abdominal region is the most common location for continuous glucose monitor (CGM) sensor insertion. However, a paucity of post-marketing data is available to demonstrate intra-individual consistency of CGM readings at different abdominal insertion sites.MethodsHealthy adults (fasting glucose (FG) < 5.5 mmol/L; BMI < 30 kg/m²) were recruited and a CGM sensor was placed on each side of the abdomen. Postprandial and continuous 48-h interstitial glucose levels were analyzed.ResultsThere was no significant difference in the 3-h postprandial glucose (PPG) level derived from the left versus right CGM, which remained non-significant after adjusting for waist circumference or FG. Among the glucose levels recorded over 48-h, values on the left site were greater in 3.6% of the data points (p < 0.05). After adjusting for waist circumference, only 0.5% of the glucose values remained significantly greater on the left (p < 0.05). When adjusted for FG, similar results were observed. For both PPG and 48-h readings, the mean absolute relative difference was not significant between the two abdominal sites.ConclusionsCGM-derived glucose measures were highly consistent between the left and right abdomen during both the postprandial and post-absorptive periods.
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- 2018
6. Lung-targeted RNAi Molecules Silence Human TSLP Expression in PCLS Cultures and Humanized Mice and Suppress Pulmonary Allergic Inflammation
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Yuan, T., primary, Klossowski, S., additional, Afrazi, M., additional, Hamilton, H., additional, Hegge, J., additional, Hamilton, J., additional, Pei, T., additional, and Bush, E.W., additional
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- 2024
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7. A Lung-targeted Therapeutic siRNA Against Highly Conserved Viral M1 mRNAs Effectively Limits Highly Pathogenic Influenza A Infection in Mice
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Zandi, K., primary, Schienebeck, C., additional, Xu, Z., additional, Saeidi, A., additional, Sheets, N., additional, Khatri, H., additional, Yuan, T., additional, Kasahara, D.I., additional, Huang, P., additional, Octaviani, C.P., additional, Hsu, J., additional, Peng, B.-H.P., additional, Tseng, C.-T.K., additional, Hamilton, J., additional, Pei, T., additional, and Bush, E.W., additional
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- 2024
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8. Hyperfine and spin-orbit coupling effects on decay of spin-valley states in a carbon nanotube
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Pei, T., Pályi, A., Mergenthaler, M., Ares, N., Mavalankar, A., Warner, J. H., Briggs, G. A. D., and Laird, E. A.
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Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
The decay of spin-valley states is studied in a suspended carbon nanotube double quantum dot via leakage current in Pauli blockade and via dephasing and decoherence of a qubit. From the magnetic field dependence of the leakage current, hyperfine and spin-orbit contributions to relaxation from blocked to unblocked states are identified and explained quantitatively by means of a simple model. The observed qubit dephasing rate is consistent with the hyperfine coupling strength extracted from this model and inconsistent with dephasing from charge noise. However, the qubit coherence time, although longer than previously achieved, is probably still limited by charge noise in the device.
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- 2016
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9. A coherent nanomechanical oscillator driven by single-electron tunnelling
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Wen, Yutian, Ares, N., Schupp, F. J., Pei, T., Briggs, G. A. D., and Laird, E. A.
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- 2020
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10. Bone mineral density and trabecular bone score in elderly type 2 diabetes Southeast Asian patients with severe osteoporotic hip fractures.
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Linsey U Gani, Kundan R Saripalli, Karen Fernandes, Suet F Leong, Koh T Tsai, Pei T Tan, Le R Chong, and Thomas F J King
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Medicine ,Science - Abstract
IntroductionStudies show trabecular bone score (TBS) may provide information regarding bone quality independent of bone mineral density (BMD) in type 2 diabetes (DM2) patients. We analyzed our Southeast Asian severe osteoporotic hip fracture patients to study these differences.MethodsWe conducted a retrospective cross-sectional analysis of subjects admitted to Changi General Hospital, Singapore with severe osteoporotic hip fractures from 2014-2017 who had BMD performed. Electronic records were reviewed and subjects were classified as having diabetes according to the WHO 2019 criteria. DM2 patients were classified according to their HbA1c into well controlled (HbA1c < 7%) and poorly controlled (HbA1c ≥ 7%) DM2.ResultsElderly patients with hip fractures present with average femur neck T scores at the osteoporotic range, however those with DM2 had higher BMD and TBS values compared to non DM2 patients. These differences were statistically significant in elderly women-poorly controlled elderly DM2 women with hip fracture had the highest total hip T-score (-2.57 ± 0.86) vs (-2.76 ± 0.96) in well controlled DM2 and (-3.09 ± 1.01) in non DM2 women with hip fracture, p < 0.001. In contrast, TBS scores were lower in poorly controlled DM2 women with hip fracture compared to well controlled DM2 women with hip fracture (1.22 ± 0.11) vs (1.24 ± 0.09), but these were still significantly higher compared to non DM2 women with hip fracture (1.19 ± 0.10), p < 0.001. In elderly men with hip fractures, univariate analysis showed no statistically significant differences in TBS or hip or LS BMD between those with poorly controlled DM2, well controlled DM2 and non DM2. The differences in TBS and BMD remained significant in all DM2 women with hip fractures even after adjustments for potential confounders. Differences in TBS and BMD in poorly controlled DM2 men with hip fractures only became significant after accounting for potential confounders. However, upon inclusion of LS BMD into the multivariate model these differences were attenuated and remained significant only between elderly women with well controlled DM2 and non DM2 women with hip fractures.ConclusionsElderly patients with DM2 and severe osteoporosis present with hip fractures at a higher BMD and TBS values compared to non DM2 patients. These differences were significant after adjustment for confounders in all DM2 women and poorly controlled DM2 men with hip fractures, TBS differences were attenuated with the inclusion LS BMD. Further studies are needed to ascertain differences in BMD and TBS in older Southeast Asian DM2 patients with variable glycemic control and severe osteoporosis.
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- 2020
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11. Maternal language use during mother-child interactions and the development of ToM in Chinese children
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Pei, T and West, G
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Correlation (Statistics) ,Education ,Language - Abstract
Mothers’ preference for introducing and elaborating on mental states in conversations with their young children has been shown to be a significant predictor of children’s Theory of Mind development among Western samples. However, it is unclear whether this relationship still holds true in the Chinese cultural context. Exploratory in nature, the present study aims to study the relationship between mothers’ mental state talk and the development of Theory of Mind (ToM) in Chinese children (4-5 years old) following the framework of Peterson and Slaughter’s (2003) research. All participants (N = 94) were from middle-income families and were Chinese mothers of a 4-5-year-old typically developing children. Fifty-two pre-schoolers (M = 4.47 years, SD = .49) were boys. Adopting a correlational study design, the current study first looks at if there were individual differences in mothers’ conversational styles with their children. By running correlational analyses examining the relationships between different conversational styles, this assumption was confirmed. Given individual differences did exist, Pearson’s correlation was performed to decide if mothers’ preferences of language use significantly correlated with ToM development in Chinese children. The result from the correlation analysis indicated that no significant correlation emerged between mothers' self-reported preferences for sophisticated explanations of mental states and parental report of children's ToM. This null result was again confirmed by a hierarchical regression analysis showing that mothers’ conversational preferences were not predictors of Chinese children’s ToM development when relevant control variables were included in the analyses. Additionally, two correlational analyses were conducted to address the research question that whether children’s age and expressive vocabulary correlate with parental reports of ToM understandings. No correlation was found between age and ToM ability. However, there was a significant correlation between children’s expressive language and ToM, giving further support to the social constructivist account. An independent samples t-test to test the gender effect on parental-report ToM yielded no significant results. Evidence of Internal consistency, content validity, and construct validity for the two translated questionnaires was given. However, accurate estimation of the psychometric properties of the two translated measures requires more research. Finally, Implications and future directions for research on the relationship between maternal mental state talk and ToM development in diverse and larger samples from a longitudinal lens were discussed.
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- 2023
12. Research on the bi-layer low carbon optimization strategy of integrated energy system based on Stackelberg master slave game
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Wu, L, Wang, C, Chen, W, Pei, T, Wu, L, Wang, C, Chen, W, and Pei, T
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With increasing reforms related to integrated energy systems (IESs), each energy subsystem, as a participant based on bounded rationality, significantly influences the optimal scheduling of the entire IES through mutual learning and imitation. A reasonable multiagent joint operation strategy can help this system meet its low-carbon objectives. This paper proposes a bilayer low-carbon optimal operational strategy for an IES based on the Stackelberg master-slave game and multiagent joint operation. The studied IES includes cogeneration, power-to-gas, and carbon capture systems. Based on the Stackelberg master-slave game theory, sellers are used as leaders in the upper layer to set the prices of electricity and heat, while energy producers, energy storage providers, and load aggregators are used as followers in the lower layer to adjust the operational strategy of the system. An IES bilayer optimization model based on the Stackelberg master-slave game was developed. Finally, the Karush-Kuhn-Tucker (KKT) condition and linear relaxation technology are used to convert the bilayer game model to a single layer. CPLEX, which is a mathematical program solver, is used to solve the equilibrium problem and the carbon emission trading cost of the system when the benefits of each subject reach maximum and to analyze the impact of different carbon emission trading prices and growth rates on the operational strategy of the system. As an experimental demonstration, we simulated an IES coupled with an IEEE 39-node electrical grid system, a six-node heat network system, and a six-node gas network system. The simulation results confirm the effectiveness and feasibility of the proposed model.
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- 2023
13. Differential scanning calorimetry predicts the critical quality attributes of amorphous glibenclamide
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Mah, Pei T., Laaksonen, Timo, Rades, Thomas, Peltonen, Leena, and Strachan, Clare J.
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- 2015
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14. Use of low-frequency Raman spectroscopy and chemometrics for the quantification of crystallinity in amorphous griseofulvin tablets
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Mah, Pei T., Fraser, Sara J., Reish, Matthew E., Rades, Thomas, Gordon, Keith C., and Strachan, Clare J.
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- 2015
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15. Role of nifedipine and hydrochlorothiazide in MAPK activation and vascular smooth muscle cell proliferation and apoptosis
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Wang, J., Liu, K., Wang, H., Li, Z., Li, Y., Ping, S., Bardeesi, A. S. A., Guo, Y., Zhou, Y., Pei, T., Deng, L., Sheng, P., Liu, S., and Li, C.
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- 2017
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16. Elucidation of Compression-Induced Surface Crystallization in Amorphous Tablets Using Sum Frequency Generation (SFG) Microscopy
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Mah, Pei T., Novakovic, Dunja, Saarinen, Jukka, Van Landeghem, Stijn, Peltonen, Leena, Laaksonen, Timo, Isomäki, Antti, and Strachan, Clare J.
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- 2017
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17. Silencing MMP7 expression with a lung-targeted RNAi molecule limits fibrosis and preserves pulmonary function in bleomycin-injured rats
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Yuan, T, primary, Nicholas, A, additional, Lakomski, N, additional, Afrazi, M, additional, Hamilton, H, additional, Hegge, J, additional, Hamilton, J, additional, Pei, T, additional, and Bush, E, additional
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- 2022
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18. Gestational Age and Cardiorespiratory Fitness in Individuals Born At Term: A Life Course Study
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Isabel Ferreira, Pei T. Gbatu, and Colin A. Boreham
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cardiorespiratory fitness ,gestational age ,longitudinal cohort study ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BackgroundIn contrast to the effects of preterm birth, the extent to which shorter gestational age affects the cardiorespiratory fitness (CRF) levels of individuals who were born at term (ie, between 37 and 42 weeks) is largely unknown. The aim of this study was to examine whether life‐course CRF levels varied across different gestational ages within the at‐term range. Methods and ResultsThe association between gestational age (in weeks) obtained from Child Health Services records and CRF, estimated from field and laboratory tests and expressed by maximal oxygen uptake level through adolescence to young adulthood, was examined in 791 participants in the Northern Ireland Young Hearts Study, all singletons born at term. Longitudinal data were analyzed with generalized estimating equations, accounting for important potential confounders. Mean levels of CRF were 45.6, 43.7, and 33.0 mL/kg per minute when participants were aged 12, 15, and 22 years, respectively. After adjustment for confounders, each week increase in gestational age was associated with 0.46 mL/kg per minute (95% confidence interval, 0.14–0.79) in CRF. Compared with individuals born full term (39–40 weeks, n=533) or late term (41–42 weeks, n=148), those who were born early term (37–38 weeks, n=110) had a higher incidence of poor CRF (risk ratio, 1.57; 95% confidence interval, 1.14–2.16). The changes in CRF through adolescence to young adulthood were similar across groups, with those born early term consistently displaying the lowest CRF. ConclusionsThese findings suggest that early‐term births within the at‐term range are linked to poorer CRF through adolescence to young adulthood, and may have important clinical and public health implications for policies about (avoidable) early‐term deliveries given their recent increasing trends.
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- 2017
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19. Silencing RAGE Expression with a Lung-Targeted RNAi Trigger Delivery Platform Suppresses Pulmonary Allergic Inflammation
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Kasahara, D.I., primary, Nicholas, A., additional, Reed, T., additional, Trilling, Z., additional, Branca-Afrazi, M., additional, Hamilton, H., additional, Hegge, J., additional, Hamilton, J., additional, Pei, T., additional, and Bush, E.W., additional
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- 2022
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20. Silencing Muc5ac Expression with a Lung-Targeted RNAi Trigger Prevents Allergen-Induced Mucoobstruction and Airway Hyperresponsiveness
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Nicholas, A., primary, Kasahara, D.I., additional, Nguyen, L., additional, Trilling, Z., additional, Blanca-Afrazi, M., additional, Hamilton, H., additional, Hegge, J., additional, Dickey, B.F., additional, Sabater, J.R., additional, Hamilton, J., additional, Pei, T., additional, and Bush, E.W., additional
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- 2022
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21. Teaching and learning methods for promoting sustainability in tourism education
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Chen, M. (Meiai), Pei, T. (Tingting), Jeronen, E. (Eila), Wang, Z. (Zhihui), Xu, L. (Lihua), Chen, M. (Meiai), Pei, T. (Tingting), Jeronen, E. (Eila), Wang, Z. (Zhihui), and Xu, L. (Lihua)
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Teaching and learning methods play an important role in promoting sustainability in tourism education. However, previous studies mainly focus on sustainability in tourism. This qualitative survey provides an overview of how sustainable development and tourism education are taught and learned in higher education institutions. It aims to support the selection of teaching and learning approaches and methods for educating sustainability-driven tourism at universities. The materials were selected based on keywords in tourism education. The study describes 32 articles published in peer-reviewed scientific journals from 2000 to 2022. The content of the articles was analyzed in detail using qualitative content analysis. Collaborative and interdisciplinary learning and case study teaching, alongside problem-based learning and experiential learning (outdoor learning), were utilized in 10 and 6 articles, respectively. Developing collaborative and interdisciplinary learning skills, developing systems thinking skills, developing experiential learning skills, and developing techniques for increasing environmental awareness were the key points of teaching and learning methods to promote sustainability in tourism education. Behavioral Change Wheel (BCW) in tourism should be implemented in school education to reach sustainable development goals and to support sustainable development.
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- 2022
22. The Impact of Exercise on Statin-Associated Skeletal Muscle Myopathy.
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Hae R Chung, Mayand Vakil, Michael Munroe, Alay Parikh, Benjamin M Meador, Pei T Wu, Jin H Jeong, Jeffrey A Woods, Kenneth R Wilund, and Marni D Boppart
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Medicine ,Science - Abstract
HMG-CoA reductase inhibitors (statins) are the most effective pharmacological means of reducing cardiovascular disease risk. The most common side effect of statin use is skeletal muscle myopathy, which may be exacerbated by exercise. Hypercholesterolemia and training status are factors that are rarely considered in the progression of myopathy. The purpose of this study was to determine the extent to which acute and chronic exercise can influence statin-induced myopathy in hypercholesterolemic (ApoE-/-) mice. Mice either received daily injections of saline or simvastatin (20 mg/kg) while: 1) remaining sedentary (Sed), 2) engaging in daily exercise for two weeks (novel, Nov), or 3) engaging in daily exercise for two weeks after a brief period of training (accustomed, Acct) (2x3 design, n = 60). Cholesterol, activity, strength, and indices of myofiber damage and atrophy were assessed. Running wheel activity declined in both exercise groups receiving statins (statin x time interaction, p
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- 2016
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23. Outcomes in unilateral primary aldosteronism after surgical or medical therapy
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Joan Khoo, Dawn Shao Ting Lim, Du Soon Swee, Roger Foo, Thomas F J King, Donovan Tay, Wann J Loh, Sarah Y Tan, Lih M Loh, Ling Zhu, Meifen Zhang, Peng C Kek, Pei T Tan, Troy H Puar, Linsey Gani, and Lynette Lee
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medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Secondary hypertension ,030209 endocrinology & metabolism ,Context (language use) ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Primary aldosteronism ,Internal medicine ,Adrenal Glands ,Hyperaldosteronism ,medicine ,Humans ,Myocardial infarction ,Stroke ,Retrospective Studies ,Models, Statistical ,business.industry ,Hazard ratio ,Adrenalectomy ,Atrial fibrillation ,Retrospective cohort study ,Prognosis ,medicine.disease ,030220 oncology & carcinogenesis ,business - Abstract
CONTEXT Studies find surgery superior to medications in the treatment of primary aldosteronism (PA). It would be ideal to compare surgical and medical therapy in patients with unilateral PA only, who have the option between these treatment modalities. However, this is challenging as most patients with unilateral PA on adrenal vein sampling (AVS) undergo surgery. OBJECTIVE To compare outcomes of surgery and medications in patients with confirmed or likely unilateral PA. DESIGN Retrospective cohort study of 274 patients with PA managed at two referral centres from 2000 to 2019. PATIENTS 154 patients identified with unilateral PA using AVS and a validated clinical prediction model were treated with surgical (n = 86) or medical (n = 68) therapy. MEASUREMENTS Primary outcome was a composite incident cardiovascular event comprising acute myocardial infarction, coronary revascularization, stroke, atrial fibrillation or congestive cardiac failure. Secondary outcomes were clinical and biochemical control. RESULTS Cardiovascular outcomes were comparable, with the surgery group having an adjusted hazard ratio of 0.93 (95% CI: 0.32-2.67), p = .89. Both treatments improved clinical and biochemical control, but surgery resulted in better systolic blood pressure, 133.0 ± 11.7 mmHg versus 137.9 ± 14.6 mmHg, p = .02, and lower defined daily dosages of antihypertensive medications, 1.0 (IQR 0.0-2.0) versus 2.6 (IQR 0.8-4.3), p
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- 2020
24. Multicarrier phase-coded design based on the genetic algorithm
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Cao, N, primary and Pei, T, additional
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- 2015
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25. Numerical Simulation of Modified Rubberized Concrete Block Under Impact Loads
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Pei, T Y, primary, Mokhatar, S N, additional, Mutalib, N A N A, additional, and Hakim, S J S, additional
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- 2021
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26. Tolerability and Efficacy of Long-Term Medical Therapy in Primary Aldosteronism
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Lynette Lee, Peng C Kek, Dawn Shao Ting Lim, Meifen Zhang, Donovan Tay, Lih M Loh, Wann J Loh, Sarah Y Tan, Pei T Tan, Du Soon Swee, Joan Khoo, Troy H Puar, Fengjie Tang, Roger Foo, Eberta Tan, Shui B Soh, and Ling Zhu
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endocrine hypertension ,subtyping ,business.industry ,Endocrinology, Diabetes and Metabolism ,adrenalectomy ,Retrospective cohort study ,medicine.disease ,Hypokalemia ,Eplerenone ,chemistry.chemical_compound ,Blood pressure ,Primary aldosteronism ,Tolerability ,chemistry ,Anesthesia ,medicine ,Spironolactone ,medicine.symptom ,mineralocorticoid receptor antagonists ,business ,Prospective cohort study ,Clinical Research Articles ,AcademicSubjects/MED00250 ,medicine.drug ,adrenal vein sampling - Abstract
Introduction Patients with primary aldosteronism (PA) have increased cardiovascular risk, and there are concerns about the efficacy of medical therapy. Objective We aimed to assess long-term tolerability and efficacy of medical therapy in PA patients. Methods We conducted a retrospective study on 201 PA patients treated with medical therapy (spironolactone, eplerenone, or amiloride) from 2000 to 2020 at 2 tertiary centers. Clinical and biochemical control and side effects were assessed. Results Among 155 patients on long-term medications, 57.4% achieved blood pressure (BP) 1 ng/mL/h. Concordance of biochemical control using potassium and renin levels was 49.1%. Side effects were experienced by 52.3% of patients, with 10.3% switching, 22.6% decreasing dose, and 11.0% stopping medications. Risk factors for side effects were spironolactone use, dose ≥ 50 mg, treatment duration ≥1 year, male gender, and unilateral PA. Patients with unilateral PA used higher spironolactone doses vs bilateral (57 vs 50 mg, P < 0.001) and had more side effects (63.2% vs 41.8%, P = 0.008). Forty-six unilateral PA patients who underwent surgery after initial medical therapy experienced improved BP (systolic from 141 to 135 mmHg, P = 0.045; diastolic from 85 to 79 mmHg, P = 0.002). Conclusion Dose-dependent side effects limit efficacy of medical therapy in PA. Future prospective studies should assess the best monitoring strategy for biochemical control during long-term medical therapy. For unilateral PA, surgery remains preferable, yielding better control with less long-term side effects.
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- 2021
27. The effect of surfactants on the dissolution behavior of amorphous formulations
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Mah, Pei T., Peltonen, Leena, Novakovic, Dunja, Rades, Thomas, Strachan, Clare J., and Laaksonen, Timo
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- 2016
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28. Tolerability and Efficacy of Long-Term Medical Therapy in Primary Aldosteronism
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Tang, Fengjie, primary, Loh, Lih M, additional, Foo, Roger S, additional, Loh, Wann J, additional, Lim, Dawn S T, additional, Zhang, Meifen, additional, Tan, Pei T, additional, Swee, Du S, additional, Khoo, Joan, additional, Tay, Donovan, additional, Lee, Lynette, additional, Tan, Sarah Y, additional, Zhu, Ling, additional, Soh, Shui B, additional, Tan, Eberta, additional, Kek, Peng C, additional, and Puar, Troy H, additional
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- 2021
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29. Physical activity levels and mental health burden of healthcare workers during COVID‐19 lockdown
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Kua, Zaylea, primary, Hamzah, Fadzil, additional, Tan, Pei T., additional, Ong, Li J., additional, Tan, Benedict, additional, and Huang, Zhongwei, additional
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- 2021
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30. Module block fault locating strategy for large-scale photovoltaic arrays
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Pei, T, Li, L, Zhang, J, and Hao, X
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Energy ,0906 Electrical and Electronic Engineering, 0913 Mechanical Engineering ,Hardware_PERFORMANCEANDRELIABILITY - Abstract
© 2020 Elsevier Ltd In practical grid-connected photovoltaic systems, faulty modules for small-scale photovoltaic arrays need to be accurately located, while the same strategy to locate each faulty module for large-scale arrays would imply high investment cost due to a large number of sensors needed. Therefore, to reduce the number of sensors and save fault monitoring investment, it suffices to identify where fault happens in a module block, which consists of several modules connected in series. For this purpose, this paper proposes a fault-locating strategy to identify faulty module blocks for large-scale arrays, where voltage sensors are deployed by differentiating the parity of string numbers in the array to acquire the terminal voltages of the module blocks between adjacent strings, and the fault locating rules for open circuit, short circuit, degradation and partial shading faults are formulated. With the help of MATLAB/Simulink platform, the proposed strategy is tested in one small-size array and two large-scale arrays, and the testing results demonstrate that the proposed strategy can locate the single fault case, multiple faults of single-type, as well as mixed faults of different sub-arrays. To summarize, the proposed fault-locating method has higher locating accuracy, lower implementation cost and wiring complexity, and is easily integrable with existing photovoltaic systems.
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- 2020
31. Bone mineral density and trabecular bone score in elderly type 2 diabetes Southeast Asian patients with severe osteoporotic hip fractures
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Le R. Chong, Koh Tzan Tsai, Suet Fen Leong, Karen Fernandes, Linsey Gani, Pei T Tan, Thomas F J King, and Kundan Reddy Saripalli
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Male ,Critical Care and Emergency Medicine ,Bone density ,Osteoporosis ,Biochemistry ,Endocrinology ,Medical Conditions ,Bone Density ,Medicine and Health Sciences ,Diabetes diagnosis and management ,Insulin ,Connective Tissue Diseases ,Musculoskeletal System ,Trauma Medicine ,Bone mineral ,Aged, 80 and over ,Hip fracture ,Multidisciplinary ,Bone Fracture ,Connective Tissue ,Cancellous Bone ,Medicine ,Female ,Anatomy ,Traumatic Injury ,Research Article ,musculoskeletal diseases ,medicine.medical_specialty ,HbA1c ,Endocrine Disorders ,Science ,Southeast asian ,Pelvis ,Trabecular bone score ,Rheumatology ,Internal medicine ,medicine ,Diabetes Mellitus ,Humans ,Femur ,Hemoglobin ,Bone ,Skeleton ,Aged ,Diabetic Endocrinology ,Hip ,business.industry ,Hip Fractures ,Biology and Life Sciences ,Proteins ,Bone fracture ,medicine.disease ,Diagnostic medicine ,Hormones ,Health Care ,Biological Tissue ,Diabetes Mellitus, Type 2 ,Metabolic Disorders ,Geriatric Care ,business ,Osteoporotic Fractures - Abstract
Introduction Studies show trabecular bone score (TBS) may provide information regarding bone quality independent of bone mineral density (BMD) in type 2 diabetes (DM2) patients. We analyzed our Southeast Asian severe osteoporotic hip fracture patients to study these differences. Methods We conducted a retrospective cross-sectional analysis of subjects admitted to Changi General Hospital, Singapore with severe osteoporotic hip fractures from 2014–2017 who had BMD performed. Electronic records were reviewed and subjects were classified as having diabetes according to the WHO 2019 criteria. DM2 patients were classified according to their HbA1c into well controlled (HbA1c < 7%) and poorly controlled (HbA1c ≥ 7%) DM2. Results Elderly patients with hip fractures present with average femur neck T scores at the osteoporotic range, however those with DM2 had higher BMD and TBS values compared to non DM2 patients. These differences were statistically significant in elderly women—poorly controlled elderly DM2 women with hip fracture had the highest total hip T-score (-2.57 ± 0.86) vs (-2.76 ± 0.96) in well controlled DM2 and (-3.09 ± 1.01) in non DM2 women with hip fracture, p < 0.001. In contrast, TBS scores were lower in poorly controlled DM2 women with hip fracture compared to well controlled DM2 women with hip fracture (1.22 ± 0.11) vs (1.24 ± 0.09), but these were still significantly higher compared to non DM2 women with hip fracture (1.19 ± 0.10), p < 0.001. In elderly men with hip fractures, univariate analysis showed no statistically significant differences in TBS or hip or LS BMD between those with poorly controlled DM2, well controlled DM2 and non DM2. The differences in TBS and BMD remained significant in all DM2 women with hip fractures even after adjustments for potential confounders. Differences in TBS and BMD in poorly controlled DM2 men with hip fractures only became significant after accounting for potential confounders. However, upon inclusion of LS BMD into the multivariate model these differences were attenuated and remained significant only between elderly women with well controlled DM2 and non DM2 women with hip fractures. Conclusions Elderly patients with DM2 and severe osteoporosis present with hip fractures at a higher BMD and TBS values compared to non DM2 patients. These differences were significant after adjustment for confounders in all DM2 women and poorly controlled DM2 men with hip fractures, TBS differences were attenuated with the inclusion LS BMD. Further studies are needed to ascertain differences in BMD and TBS in older Southeast Asian DM2 patients with variable glycemic control and severe osteoporosis.
- Published
- 2020
32. The use of hydrophobic amino acids in protecting spray dried trehalose formulations against moisture-induced changes
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Jayne E. Hastedt, Anne Marie Healy, Irina Gitlin, Peter O'Connell, John V. Fahy, Pei T. Mah, Ross Lundy, Stefano Focaroli, Tom F. O'Mahony, and Stefan Oscarson
- Subjects
Recrystallization (geology) ,Moisture protection ,Chemistry, Pharmaceutical ,Drug Compounding ,Pharmaceutical Science ,02 engineering and technology ,030226 pharmacology & pharmacy ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Leucine ,Administration, Inhalation ,Pharmacology & Pharmacy ,Amino Acids ,Aerosolization ,chemistry.chemical_classification ,Aerosols ,Chromatography ,L-isoleucine ,Moisture ,Chemistry ,Spray drying ,Humidity ,Trehalose ,Sorption ,Dry Powder Inhalers ,Recrystallization ,General Medicine ,Pharmacology and Pharmaceutical Sciences ,021001 nanoscience & nanotechnology ,Amino acid ,Hygroscopic ,Inhalation ,Administration ,Pharmaceutical ,Wettability ,Powders ,0210 nano-technology ,L-leucine ,Hydrophobic and Hydrophilic Interactions ,Biotechnology - Abstract
Trehalose is commonly used as a protein stabilizer in spray dried protein formulations delivered via the pulmonary route. Spray dried trehalose formulations are highly hygroscopic, which makes them prone to deliquescence and recrystallization when exposed to moisture, leading to impairment in aerosolization performance. The main aim of this study was to investigate and compare the effect of hydrophobic amino acids (i.e. L-leucine and L-isoleucine) in enhancing aerosolization performance and in mitigating moisture-induced changes in spray dried trehalose formulations. Trehalose was spray dried with 20–60% w/w of amino acid (i.e. L-leucine or L-isoleucine). The spray dried formulations were stored at 25 °C/50% RH for 28 days. Solid state characterization and in vitro aerosolization performance studies were performed on the spray dried formulations before and after storage. The addition of 20–60% w/w of amino acid (i.e. L-leucine or L-isoleucine) improved the emitted fractions of spray dried trehalose formulations from a dry powder inhaler. However, ≥ 40% w/w of L-leucine/L-isoleucine was needed to prevent recrystallization of trehalose in the formulations when exposed to 25 °C/50% RH for 28 days. X-ray photoelectron spectroscopy (XPS) demonstrated that samples with 40–60% w/w L-isoleucine had more amino acid on the surfaces of the particles compared to their L-leucine counterparts. This may explain the greater ability of the L-isoleucine (40–60% w/w) samples to cope with elevated humidity compared to L-leucine samples of the same concentrations, as observed in the dynamic vapour sorption (DVS) studies. In conclusion, this study demonstrated that both L-leucine and L-isoleucine were effective in enhancing aerosolization performance and mitigating moisture-induced reduction in aerosolization performance in spray dried trehalose formulations. L-isoleucine proved to be superior to L-leucine in terms of its moisture protectant effect when incorporated at the same concentration in the formulations.
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- 2019
33. Bone mineral density and trabecular bone score in elderly type 2 diabetes Southeast Asian patients with severe osteoporotic hip fractures
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Gani, Linsey U., primary, Saripalli, Kundan R., additional, Fernandes, Karen, additional, Leong, Suet F., additional, Tsai, Koh T., additional, Tan, Pei T., additional, Chong, Le R., additional, and King, Thomas F. J., additional
- Published
- 2020
- Full Text
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34. Physical activity levels and mental health burden of healthcare workers during COVID‐19 lockdown.
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Kua, Zaylea, Hamzah, Fadzil, Tan, Pei T., Ong, Li J., Tan, Benedict, and Huang, Zhongwei
- Subjects
COVID-19 ,JOB stress prevention ,MENTAL depression risk factors ,WELL-being ,CROSS-sectional method ,JOB stress ,MEDICAL personnel ,PHYSICAL activity ,PSYCHOSOCIAL factors ,DESCRIPTIVE statistics ,EXERCISE intensity ,STAY-at-home orders ,ANXIETY ,COVID-19 pandemic ,HEALTH promotion - Abstract
The outbreak of COVID‐19 has precipitated international lockdown measures to curb disease transmissions. The closure of public activity spaces as well as changes in pandemic workload may disrupt healthcare workers' physical activity and self‐care routines. We sought to examine the association between physical activity levels and mental health burden of healthcare workers during the COVID‐19 lockdown in Singapore. This cross‐sectional study comprised of an multidomain survey that was administered digitally to 707 healthcare workers between 17 May and 18 June 2020. Exercise frequency, duration and intensity of these healthcare workers had reduced significantly during the lockdown compared to pre‐lockdown. 25.3%, 37.2%, and 11.9% had screened positive for moderate‐to‐extremely‐severe depression, anxiety and stress respectively. Reductions in exercise duration was a significant risk factor for mild stress and moderate‐to‐severe depression while increase in exercise frequency was found to be a protective factor against depressed mood. Our study revealed that a short‐term reduction in physical activity levels during lockdown was associated with poorer psychological outcomes. Given the protection that exercise confers on depression, physical activity should be promoted at the workplace and at home to support healthcare workers to cope through this protracted health crisis. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
35. Outcomes in unilateral primary aldosteronism after surgical or medical therapy
- Author
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Puar, Troy H., primary, Loh, Lih M., additional, Loh, Wann J., additional, Lim, Dawn S. T., additional, Zhang, Meifen, additional, Tan, Pei T., additional, Lee, Lynette, additional, Swee, Du S., additional, Khoo, Joan, additional, Tay, Donovan, additional, Tan, Sarah Y., additional, Zhu, Ling, additional, Gani, Linsey, additional, King, Thomas F., additional, Kek, Peng C., additional, and Foo, Roger S., additional
- Published
- 2020
- Full Text
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36. Therapeutic Silencing of ENaC Expression with a Pulmonary Epithelial RNAi Trigger Delivery Platform Durably Improves Clearance in a Large Animal Model of Muco-Obstructive Lung Disease
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Bush, E.W., primary, Nicholas, A., additional, Sabater, J.R., additional, Pei, T., additional, Li, X., additional, Glebocka, A., additional, Trilling, Z., additional, Salathe, M.A., additional, Dickey, B.F., additional, Rowe, S.M., additional, Given, B., additional, and Mall, M.A., additional
- Published
- 2020
- Full Text
- View/download PDF
37. The use of hydrophobic amino acids in protecting spray dried trehalose formulations against moisture-induced changes
- Author
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Mah, Pei T., primary, O'Connell, Peter, additional, Focaroli, Stefano, additional, Lundy, Ross, additional, O'Mahony, Tom F., additional, Hastedt, Jayne E., additional, Gitlin, Irina, additional, Oscarson, Stefan, additional, Fahy, John V., additional, and Healy, Anne Marie, additional
- Published
- 2019
- Full Text
- View/download PDF
38. The effect of surfactants on the dissolution behavior of amorphous formulations
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Timo Laaksonen, Thomas Rades, Clare J. Strachan, Dunja Novakovic, Pei T. Mah, and Leena Peltonen
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Materials science ,Spectrophotometry, Infrared ,Indomethacin ,Pharmaceutical Science ,02 engineering and technology ,030226 pharmacology & pharmacy ,law.invention ,Surface-Active Agents ,03 medical and health sciences ,0302 clinical medicine ,Pulmonary surfactant ,law ,medicine ,Organic chemistry ,Solubility ,Crystallization ,Dissolution ,Supersaturation ,General Medicine ,021001 nanoscience & nanotechnology ,Amorphous solid ,Chemical engineering ,Poloxamer 407 ,Wetting ,0210 nano-technology ,Biotechnology ,medicine.drug - Abstract
The optimal design of oral amorphous formulations benefits from the use of excipients to maintain drug supersaturation and thus ensures adequate absorption during intestinal transit. The use of surfactants for the maintenance of supersaturation in amorphous formulations has not been investigated in detail. The main aim of this study was to investigate the effect of surfactant on the dissolution behavior of neat amorphous drug and binary polymer based solid dispersion. Indomethacin was used as the model drug and the surfactants studied were polysorbate 80 and poloxamer 407. The presence of surfactants (alone or in combination with polymers) in the buffer was detrimental to the dissolution of neat amorphous indomethacin, suggesting that the surfactants promoted the crystallization of neat amorphous indomethacin. In contrast, the presence of surfactants (0.01% w/v) in the buffer resulted in a significant improvement on the dissolution behavior of binary polymer based solid dispersion. Incorporating the surfactant to the formulation to form ternary solid dispersion adversely affected the dissolution behavior. In conclusion, the use of surfactants (as wetting or solubilization agents) in dissolution studies of neat amorphous drugs requires prudent consideration. The design of amorphous formulations with optimal dissolution performance requires the appropriate selection of a combination of excipients and consideration of the method of introducing the excipients.
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- 2016
39. Consistency of Continuous Ambulatory Interstitial Glucose Monitoring Sensors
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Kim-Lien Nguyen, Catherine Lee, Pei T Wu, and David E Segovia
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Adult ,Male ,medicine.medical_specialty ,Waist ,Monitoring ,Adolescent ,Clinical Biochemistry ,Monitoring, Ambulatory ,030209 endocrinology & metabolism ,intra-subject agreement ,Article ,Analytical Chemistry ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Consistency (statistics) ,Internal medicine ,Ambulatory ,medicine ,Humans ,030212 general & internal medicine ,continuous glucose monitoring ,interstitial glucose sensors ,postprandial glucose ,business.industry ,Significant difference ,Diabetes ,nutritional and metabolic diseases ,General Medicine ,Middle Aged ,Circumference ,Postprandial ,medicine.anatomical_structure ,Glucose ,Cardiology ,Interstitial glucose ,Abdomen ,Female ,Biochemistry and Cell Biology ,business - Abstract
Aims: The abdominal region is the most common location for continuous glucose monitor (CGM) sensor insertion. However, a paucity of post-marketing data is available to demonstrate intra-individual consistency of CGM readings at different abdominal insertion sites. Methods: Healthy adults (fasting glucose (FG) < 5.5 mmol/L; BMI < 30 kg/m2) were recruited and a CGM sensor was placed on each side of the abdomen. Postprandial and continuous 48-h interstitial glucose levels were analyzed. Results: There was no significant difference in the 3-h postprandial glucose (PPG) level derived from the left versus right CGM, which remained non-significant after adjusting for waist circumference or FG. Among the glucose levels recorded over 48-h, values on the left site were greater in 3.6% of the data points (p < 0.05). After adjusting for waist circumference, only 0.5% of the glucose values remained significantly greater on the left (p < 0.05). When adjusted for FG, similar results were observed. For both PPG and 48-h readings, the mean absolute relative difference was not significant between the two abdominal sites. Conclusions: CGM-derived glucose measures were highly consistent between the left and right abdomen during both the postprandial and post-absorptive periods.
- Published
- 2018
40. A coherent nanomechanical oscillator driven by single-electron tunnelling
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Wen, Yutian, primary, Ares, N., additional, Schupp, F. J., additional, Pei, T., additional, Briggs, G. A. D., additional, and Laird, E. A., additional
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- 2019
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41. The Influence of Loading Force on Ultrasonic Drilling Garnet Ferrite
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Pei, T H, primary, Zhang, X F, additional, Wang, Q, additional, Zhang, T Y, additional, Zhong, Y, additional, and Zhu, Y Y, additional
- Published
- 2019
- Full Text
- View/download PDF
42. Use of low-frequency Raman spectroscopy and chemometrics for the quantification of crystallinity in amorphous griseofulvin tablets
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Keith C. Gordon, Clare J. Strachan, Sara J. Fraser, Pei T. Mah, Thomas Rades, and Matthew E. Reish
- Subjects
Materials science ,Phonon ,010401 analytical chemistry ,Analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Transmission Raman spectroscopy ,0104 chemical sciences ,Amorphous solid ,Chemometrics ,Crystallinity ,symbols.namesake ,symbols ,0210 nano-technology ,Raman spectroscopy ,Spectroscopy ,Raman scattering - Abstract
Low-frequency Raman spectroscopy, which directly probes phonon lattice modes of crystal structures, has much unexplored potential for sensitive qualitative and quantitative analysis of crystallinity in drugs and excipients. In this study, the level of crystallinity in tablets containing amorphous drug is quantified using low-frequency Raman spectroscopy in concert with chemometrics for the first time. Importantly, these data are directly compared to simultaneously obtained mid-frequency Raman spectra, as well as to FT-Raman data, which is commonly used for such quantification. Griseofulvin was used as a model drug. The PLS model using FT-Raman spectroscopy gave a root mean squared error of prediction (RMSEP) of 0.65%. The PLS models of the low- and mid-frequency regions using a charge coupled device (CCD) based Raman system with 785 nm excitation gave an RMSEP = 1.2% when using the low-frequency region (5–120 cm −1 ) and RMSEP = 1.4% for the mid-range frequencies (520–1740 cm −1 ). The recrystallization profiles determined using the various Raman techniques and their associated models were similar. The FT-Raman and the low frequency Raman systems were able to detect and quantify crystallinity in stored amorphous samples earlier than the mid-frequency 785 nm Raman system. Overall, this study suggests that low-frequency Raman spectroscopy has at least equally good performance compared to mid-frequency Raman for quantitative analysis of crystallinity in the pharmaceutical setting. More generally, the much stronger Raman scattering in the low-frequency region combined with the intrinsic spectral differences between amorphous and crystalline materials may prove advantageous for some analyses.
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- 2015
43. Outcomes in unilateral primary aldosteronism after surgical or medical therapy.
- Author
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Puar, Troy H., Loh, Lih M., Loh, Wann J., Lim, Dawn S. T., Zhang, Meifen, Tan, Pei T., Lee, Lynette, Swee, Du S., Khoo, Joan, Tay, Donovan, Tan, Sarah Y., Zhu, Ling, Gani, Linsey, King, Thomas F., Kek, Peng C., and Foo, Roger S.
- Subjects
CEREBRAL revascularization ,CLINICAL prediction rules ,SYSTOLIC blood pressure ,MYOCARDIAL infarction ,HYPERALDOSTERONISM ,ATRIAL fibrillation ,HEART failure - Abstract
Context: Studies find surgery superior to medications in the treatment of primary aldosteronism (PA). It would be ideal to compare surgical and medical therapy in patients with unilateral PA only, who have the option between these treatment modalities. However, this is challenging as most patients with unilateral PA on adrenal vein sampling (AVS) undergo surgery. Objective: To compare outcomes of surgery and medications in patients with confirmed or likely unilateral PA. Design: Retrospective cohort study of 274 patients with PA managed at two referral centres from 2000 to 2019. Patients: 154 patients identified with unilateral PA using AVS and a validated clinical prediction model were treated with surgical (n = 86) or medical (n = 68) therapy. Measurements: Primary outcome was a composite incident cardiovascular event comprising acute myocardial infarction, coronary revascularization, stroke, atrial fibrillation or congestive cardiac failure. Secondary outcomes were clinical and biochemical control. Results: Cardiovascular outcomes were comparable, with the surgery group having an adjusted hazard ratio of 0.93 (95% CI: 0.32–2.67), p =.89. Both treatments improved clinical and biochemical control, but surgery resulted in better systolic blood pressure, 133.0 ± 11.7 mmHg versus 137.9 ± 14.6 mmHg, p =.02, and lower defined daily dosages of antihypertensive medications, 1.0 (IQR 0.0–2.0) versus 2.6 (IQR 0.8–4.3), p <.001. In addition, 12 of 86 patients in the surgery group failed medical therapy before opting for surgery. Conclusion: In patients with unilateral PA who can tolerate medications, medical therapy improves clinical and biochemical control, and may offer similar cardiovascular protection. However, surgery reduces pill burden, may cure hypertension and is recommended for unilateral PA. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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44. Gestational Age and Cardiorespiratory Fitness in Individuals Born At Term: A Life Course Study
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Pei T. Gbatu, Colin Boreham, and Isabel Ferreira
- Subjects
Male ,Pediatrics ,medicine.medical_specialty ,Adolescent ,Term Birth ,Epidemiology ,Gestational Age ,Northern Ireland ,Young Adult ,03 medical and health sciences ,Child Development ,Oxygen Consumption ,0302 clinical medicine ,Risk Factors ,030225 pediatrics ,Odds Ratio ,medicine ,Humans ,Longitudinal Studies ,030212 general & internal medicine ,Young adult ,Child ,Exercise ,Original Research ,cardiorespiratory fitness ,business.industry ,Age Factors ,Infant, Newborn ,Gestational age ,longitudinal cohort study ,Cardiorespiratory fitness ,Odds ratio ,Adolescent Development ,Child development ,Term (time) ,Primary Prevention ,Linear Models ,Life course approach ,Female ,Cardiology and Cardiovascular Medicine ,business - Abstract
Background In contrast to the effects of preterm birth, the extent to which shorter gestational age affects the cardiorespiratory fitness ( CRF ) levels of individuals who were born at term (ie, between 37 and 42 weeks) is largely unknown. The aim of this study was to examine whether life‐course CRF levels varied across different gestational ages within the at‐term range. Methods and Results The association between gestational age (in weeks) obtained from Child Health Services records and CRF , estimated from field and laboratory tests and expressed by maximal oxygen uptake level through adolescence to young adulthood, was examined in 791 participants in the Northern Ireland Young Hearts Study, all singletons born at term. Longitudinal data were analyzed with generalized estimating equations, accounting for important potential confounders. Mean levels of CRF were 45.6, 43.7, and 33.0 mL/kg per minute when participants were aged 12, 15, and 22 years, respectively. After adjustment for confounders, each week increase in gestational age was associated with 0.46 mL/kg per minute (95% confidence interval , 0.14–0.79) in CRF . Compared with individuals born full term (39–40 weeks, n=533) or late term (41–42 weeks, n=148), those who were born early term (37–38 weeks, n=110) had a higher incidence of poor CRF (risk ratio, 1.57; 95% confidence interval , 1.14–2.16). The changes in CRF through adolescence to young adulthood were similar across groups, with those born early term consistently displaying the lowest CRF. Conclusions These findings suggest that early‐term births within the at‐term range are linked to poorer CRF through adolescence to young adulthood, and may have important clinical and public health implications for policies about (avoidable) early‐term deliveries given their recent increasing trends.
- Published
- 2017
45. Abstract 35: In Singletons Born at Term, Lower Gestational Age is Associated with Lower Cardiorespiratory Fitness Levels Through Adolescence to Young Adulthood: The Northern Ireland Young Hearts Project (NIYHP)
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Isabel Ferreira, Pei T Gbatu, and Colin Boreham
- Subjects
Physiology (medical) ,Cardiology and Cardiovascular Medicine - Abstract
Decreases in the mean gestational age of term deliveries have been reported over the past decade in several developed countries, linked to increases in the rates of planned births by labour induction and/or pre-labour caesarean sections. In contrast to the effects of pre-term birth, the extent to which lower gestation age within the at-term range (i.e. 37 to 42 weeks) affects individuals’ cardiorespiratory fitness (CRF) health is largely unknown, however. We therefore examined the association between gestational age, accounting for other important perinatal covariates (obtained from the NI Child Health Services’ records), and CRF (VO 2 max) as measured through adolescence to young adulthood in 842 (51.5% female) participants in the NIYHP (all singletons born at term, 98% of whom with birth weight greater than 2.5 kg). Participants’ mean levels of CRF were 45.6 ± 4.8, 43.7 ± 6.8 and 32.9 ± 9.8 ml/kg/min at the ages of 12, 15 and 22 years, respectively. With the use of GEE analyses adjusted for age, sex, socio economic status, birth weight z-scores (relative to UK’s 1990 reference), breast-feeding practices and duration, maternal age at child’s birth and delivery mode, we found that each week increase in gestational age was associated with 0.44 ml/kg/min (95% CI 0.13 to 0.75) higher levels of CRF throughout the whole longitudinal period (p=0.005). Further adjustments for participants’ height, body fatness and maturational level throughout the longitudinal period only attenuated this association slightly [to 0.38 ml/kg/min (95% CI 0.12 to 0.65), p=0.005]. There were no significant interactions between gestational age and sex or participants’ age at the time of CRF assessment, indicating that the decreases in CRF over time were similar across the different gestational ages, with those born early term displaying consistently lower levels throughout the longitudinal period. Finally, each week increase in gestation age was associated with lower risk of poor CRF through adolescence to young adulthood as defined according to current age and sex-specific health-reference values of VO 2 max: RR=0.89 (95% 0.81 to 0.97), p=0.008. These findings suggest that lower gestational age, even within the at-term range , may be a key determinant of poorer CRF as each additional week conferred benefits. This aspect may have been neglected by the over-simplistic characterisation of individuals born at-term as a homogeneous group and may have public health and clinical implications for policies around planned deliveries, given the current trends.
- Published
- 2017
46. Elucidation of Compression-Induced Surface Crystallization in Amorphous Tablets Using Sum Frequency Generation (SFG) Microscopy
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Timo Laaksonen, Jukka Saarinen, Antti Isomäki, Pei T. Mah, Dunja Novakovic, Stijn Van Landeghem, Clare J. Strachan, Leena Peltonen, Faculty of Pharmacy, Division of Pharmaceutical Chemistry and Technology, Preclinical Drug Formulation and Analysis group, Nanobio Pharmaceutics, Department of Anatomy, Medicum, Clare Strachan / Research Group, Formulation and industrial pharmacy, Drug Research Program, and Pharmaceutical Spectroscopy and Imaging
- Subjects
Materials science ,crystallization ,Scanning electron microscope ,amorphous ,Chemistry, Pharmaceutical ,Analytical chemistry ,Pharmaceutical Science ,02 engineering and technology ,Polyethylene glycol ,Methylcellulose ,030226 pharmacology & pharmacy ,law.invention ,Polyethylene Glycols ,Excipients ,03 medical and health sciences ,chemistry.chemical_compound ,Crystallinity ,0302 clinical medicine ,law ,Microscopy ,Spectroscopy, Fourier Transform Infrared ,Pressure ,Pharmacology (medical) ,sum frequency generation (SFG) microscopy ,Crystallization ,griseofulvin ,Cellulose ,Pharmacology ,attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy ,Organic Chemistry ,021001 nanoscience & nanotechnology ,Silicon Dioxide ,compression ,Amorphous solid ,Microcrystalline cellulose ,chemistry ,Chemical engineering ,317 Pharmacy ,Attenuated total reflection ,Microscopy, Electron, Scanning ,Molecular Medicine ,scanning electron microscopy (SEM) ,0210 nano-technology ,Biotechnology ,Tablets - Abstract
Purpose To investigate the effect of compression on the crystallization behavior in amorphous tablets using sum frequency generation (SFG) microscopy imaging and more established analytical methods. Method Tablets containing neat amorphous griseofulvin with/without excipients (silica, hydroxypropyl methylcellulose acetate succinate (HPMCAS), microcrystalline cellulose (MCC) and polyethylene glycol (PEG)) were prepared. They were analyzed upon preparation and storage using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and SFG microscopy. Results Compression-induced crystallization occurred predominantly on the surface of the neat amorphous griseofulvin tablets, with minimal crystallinity being detected in the core of the tablets. The presence of various types of excipients was not able to mitigate the compression-induced surface crystallization of the amorphous griseofulvin tablets. However, the excipients affected the crystallization rate of amorphous griseofulvin in the core of the tablet upon compression and storage. Conclusion SFG microscopy can be used in combination with ATR-FTIR spectroscopy and SEM to understand the crystallization behaviour of amorphous tablets upon compression and storage. When selecting excipients for amorphous formulations, it is important to consider the effect of the excipients on the physical stability of the amorphous formulations.
- Published
- 2017
47. Measuring carbon nanotube vibrations using a single-electron transistor as a fast linear amplifier
- Author
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Wen, Yutian, primary, Ares, N., additional, Pei, T., additional, Briggs, G. A. D., additional, and Laird, E. A., additional
- Published
- 2018
- Full Text
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48. WS09.4 Targeting αENaC with an epithelial RNAi trigger delivery platform for the treatment of cystic fibrosis
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Bush, E.W., primary, Nicholas, A., additional, Pei, T., additional, Kuipers, I., additional, Cheng, W., additional, Hamilton, H., additional, Hegge, J., additional, Li, X., additional, Glebocka, A., additional, Zhu, R., additional, Chen, B., additional, Kuehl, P., additional, Schluep, T., additional, and Li, Z., additional
- Published
- 2018
- Full Text
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49. 1200 SIRT7 epigenetically regulates MITF to promote melanoma growth
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Guo, W., primary, Ma, J., additional, Pei, T., additional, Wang, S., additional, Guo, S., additional, Gao, T., additional, and Li, C., additional
- Published
- 2018
- Full Text
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50. 1195 Up-regulated deubiquitinase USP4 plays an oncogenic role in melanoma
- Author
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Guo, S., primary, Guo, W., additional, Ma, J., additional, Pei, T., additional, Li, C., additional, and Shi, Q., additional
- Published
- 2018
- Full Text
- View/download PDF
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