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Fulltext Modeling the Impact of Phonon Scattering with Strain Effects on the Electrical Properties of MoS2 Field-Effect Transistors

Chin HC, Hamzah A, Alias NE, Tan MLP

Micromachines (Basel), 2023 Jun 12;14(6).
PMID: 37374820 DOI: 10.3390/mi14061235

Molybdenum disulfide (MoS2) has distinctive electronic and mechanical properties which make it a highly prospective material for use as a channel in upcoming nanoelectronic devices. An analytical modeling framework was used to investigate the I-V characteristics of field-effect transistors based on MoS2. The study begins by developing a ballistic current equation using a circuit model with two contacts. The transmission probability, which considers both the acoustic and optical mean free path, is then derived. Next, the effect of phonon scattering on the device was examined by including transmission probabilities into the ballistic current equation. According to the findings, the presence of phonon scattering caused a decrease of 43.7% in the ballistic current of the device at room temperature when L = 10 nm. The influence of phonon scattering became more prominent as the temperature increased. In addition, this study also considers the impact of strain on the device. It is reported that applying compressive strain could increase the phonon scattering current by 13.3% at L = 10 nm at room temperature, as evaluated in terms of the electrons' effective masses. However, the phonon scattering current decreased by 13.3% under the same condition due to the existence of tensile strain. Moreover, incorporating a high-k dielectric to mitigate the impact of scattering resulted in an even greater improvement in device performance. Specifically, at L = 6 nm, the ballistic current was surpassed by 58.4%. Furthermore, the study achieved SS = 68.2 mV/dec using Al2O3 and an on-off ratio of 7.75 × 104 using HfO2. Finally, the analytical results were validated with previous works, showing comparable agreement with the existing literature.
Fulltext Analytical modeling of glucose biosensors based on carbon nanotubes

Pourasl AH, Ahmadi MT, Rahmani M, Chin HC, Lim CS, Ismail R, et al.

Nanoscale Res Lett, 2014 Jan 15;9(1):33.
PMID: 24428818 DOI: 10.1186/1556-276X-9-33

In recent years, carbon nanotubes have received widespread attention as promising carbon-based nanoelectronic devices. Due to their exceptional physical, chemical, and electrical properties, namely a high surface-to-volume ratio, their enhanced electron transfer properties, and their high thermal conductivity, carbon nanotubes can be used effectively as electrochemical sensors. The integration of carbon nanotubes with a functional group provides a good and solid support for the immobilization of enzymes. The determination of glucose levels using biosensors, particularly in the medical diagnostics and food industries, is gaining mass appeal. Glucose biosensors detect the glucose molecule by catalyzing glucose to gluconic acid and hydrogen peroxide in the presence of oxygen. This action provides high accuracy and a quick detection rate. In this paper, a single-wall carbon nanotube field-effect transistor biosensor for glucose detection is analytically modeled. In the proposed model, the glucose concentration is presented as a function of gate voltage. Subsequently, the proposed model is compared with existing experimental data. A good consensus between the model and the experimental data is reported. The simulated data demonstrate that the analytical model can be employed with an electrochemical glucose sensor to predict the behavior of the sensing mechanism in biosensors.
Infestation with the cat flea, Ctenocephalides felis felis (Siphonaptera: Pulicidae) among students in Kuala Lumpur, Malaysia

Chin HC, Ahmad NW, Lim LH, Jeffery J, Hadi AA, Othman H, et al.

Southeast Asian J. Trop. Med. Public Health, 2010 Nov;41(6):1331-4.
PMID: 21329307

This paper reports six male undergraduate students living at a local university hostel who were infested with cat fleas (Siphonaptera: Pulicidae: Ctenocephalides felis felis) in February 2009. All of them suffered from maculopapular rashes and severe pruritus after the bites. Investigation revealed the presence of a stray cat in the hostel building; five of the students had a history of contact with the cat. Six cat fleas were collected at the hostel and identified as C. felis felis. Most of the students were not aware of this infestation and did not seek medical treatment.
Safety and Effectiveness of Del Nido Cardioplegia in Comparison to Blood-Based St. Thomas Cardioplegia in Congenital Heart Surgeries: A Prospective Randomized Controlled Study

Haranal M, Chin HC, Sivalingam S, Raja N, Mohammad Shaffie MS, Namasiwayam TK, et al.

World J Pediatr Congenit Heart Surg, 2020 Nov;11(6):720-726.
PMID: 33164692 DOI: 10.1177/2150135120936119

BACKGROUND: To compare the safety and effectiveness of del Nido cardioplegia with blood-based St Thomas Hospital (BSTH) cardioplegia in myocardial protection in congenital heart surgery.
METHODS: It is a prospective, open-labeled, randomized controlled study conducted at National Heart Institute, Kuala Lumpur from July 2018 to July 2019. All patients with simple and complex congenital heart diseases (CHD) with good left ventricular function (left ventricular ejection fraction [LVEF] >50%) were included while those with LVEF <50% were excluded. A total of 100 patients were randomized into two groups of 50 each receiving either del Nido or BSTH cardioplegia. Primary end points were the spontaneous return of activity following aortic cross-clamp release and ventricular function between two groups. Secondary end point was myocardial injury as assessed by troponin T levels.
RESULTS: Cardiopulmonary bypass and aortic cross-clamp time, return of spontaneous cardiac activity following the aortic cross-clamp release, the duration of mechanical ventilation, and intensive care unit stay were comparable between two groups. Statistically significant difference was seen in the amount and number of cardioplegia doses delivered (P < .001). The hemodilution was significantly less in the del Nido complex CHD group compared to BSTH cardioplegia (P = .001) but no difference in blood usage (P = .36). The myocardial injury was lesser (lower troponin T release) with del Nido compared to BSTH cardioplegia (P = .6).
CONCLUSION: Our study showed that both del Nido and BSTH cardioplegia are comparable in terms of myocardial protection. However, single, less frequent, and lesser volume of del Nido cardioplegia makes it more suitable for complex repair.
Fulltext Aural myiasis in a neonate in peninsular Malaysia

Ahmad NW, Ismail A, Jeffery J, Ibrahim S, Hadi AA, Ibrahim MN, et al.

Parasit Vectors, 2009;2(1):63.
PMID: 20003466 DOI: 10.1186/1756-3305-2-63

Myiasis is a pathological condition in humans and animals caused by various species of dipterous larvae. Myiasis which occurs in a newborn baby is referred as neonatal myiasis. It is a rare condition and there are only a few reports to date. A case of neonatal aural myiasis in a two day old infant is reported in this paper.
Fulltext Predation on pupa of Chrysomya rufifacies (Marquart) (Diptera: Calliphoridae) by parasitoid, Exoristobia philippinensis Ashmead (Hymenoptera: Encyrtidae) and Ophyra spinigera larva (Diptera: Muscidae)

Chin HC, Ahmad NW, Lim LH, Jeffery J, Omar B, Dhang CC, et al.

Trop Biomed, 2009 Dec;26(3):369-72.
PMID: 20237454

A forensic entomological study was conducted using monkey carcasses (Macaca fascicularis Raffles) that were placed in either an outdoor or indoor environment at a coastal area in Tanjung Sepat, Selangor, Malaysia during May until August 2008. We collected pupae of Chrysomya rufifacies (Marquart) from the carcasses and kept them individually. The emergence of 13 parasitic microhymenopteran, from one of the pupae occurring within a week were identified as Exoristobia philippinensis Ashmead (Hymenoptera: Encyrtidae). Another observation was made whereby a pupa of C. rufifacies was predated by a muscid larva, Ophyra spinigera (Stein). The larva squeezed into the pupa and consumed the contents. This paper report C. rufifacies as a new host record for E. philippinensis in Malaysia and highlighted the predatory behavior of O. spinigera larva in natural environment.
Fulltext Buckling up in Singapore: residency and other risk factors for seatbelt non-compliance - a cross-sectional study based on trauma registry data

Wong TH, Lim GH, Chow KY, Trauma Coordinators and Trauma Service Representatives, Zaw NN, Nguyen HV, et al.

BMC Public Health, 2016 05 14;16:402.
PMID: 27180046 DOI: 10.1186/s12889-016-3080-3

BACKGROUND: Seatbelt non-compliance is a problem in middle income countries, and little is known about seatbelt compliance in populations with a high proportion of non-residents. This study analyses the profile of seatbelt non-compliance in Singapore based on trauma registry data from five of the six public hospitals.
METHODS: This is a cross-sectional study of seatbelt compliance of patients aged over 18 years, attending the emergency departments of five public hospitals in Singapore after road collisions from 2011-2014. Seatbelt data was obtained from paramedic and patient history.
RESULTS: There were 4,576 patients studied. Most were Singapore citizens (83.4 %) or permanent residents (2.4 %), with the largest non-resident groups from Malaysia, India, and China. Overall seatbelt compliance was 82.1 %. On univariate analysis, seatbelt compliance was higher in older patients (OR 1.02, 95 % CI 1.001-1.021, p
Fulltext Myospila pudica pudica (Stein, 1915) (Diptera: Muscidae) in peninsular Malaysia and its occurrence on a monkey carrion

Zuha RM, Kurahashi H, Chin HC, Osman K, Rashid RA, Hassan RA, et al.

Trop Biomed, 2009 Aug;26(2):216-8.
PMID: 19901908

Myospila pudica pudica (Stein, 1915) (Diptera: Muscidae) was recorded for the first time in Malaysia during a forensic entomological study conducted at a forested area of Forensic Science Simulation Site, Faculty of Allied Health Sciences Universiti Kebangsaan Malaysia, Bangi, Selangor. This species can be differentiated from other species of its genus by having R1 setulose on dorsal surface and R4+5 more or less setulose dorsally and ventrally. The legs, including tarsi, are testaceous yellow and palpi blackish. Lateral and ventral surface of scutellum bare below the level of bristles and the third antennal segment is brownish yellow. Other features including the diverging of inner margin of lower squama from scutellum margin. This is also the first report on the occurence of M. pudica pudica (Stein, 1915) on animal carcass.