Simulation of transport in laterally gated junctionless transistors fabricated by local anodization with an atomic force microscope

In this paper, we have investigated the characteristics and transport features of junctionless lateral gate transistors via measurement and simulations. The transistor is fabricated using an atomic force microscopy (AFM) nanolithography technique on silicon-on-insulator (SOI) wafer. This work develops our previous examination of the device operation by using 3D numerical simulations to offer a better understanding of the origin of the transistor operation. We compare the experimental measurements and simulation results in the transfer characteristic and drain conductance. We also explore the behavior of the device in on and off states based on the variation of majority and minority carriers' density, electric-field components, and recombination/generation rate of carriers in the active region of the device. We show that the device is a normally on device that can force the current through a depleted region (off state) and uses bulk conduction instead of surface conduction. We also found that due to the lateral gate design, low-doped channel, and lack of the gate oxide the electrostatic squeezing of the channel effectively forces the device into the off state, but the current improvement by accumulation of carriers is not significant

Low Noise, High Gain RF Front End Receiver at 5.8GHz for WiMAX Application

This paper presents the design of a high gain, low noise direct conversion Radio frequency(RF) front-end receiver system. The Front end receiver is designed to operate at 5.8 GHz in compliant with IEEE 802.16 WiMAX standard. The system consists of a low noise amplifier (LNA), a radio frequency amplifier (RFA), a power divider and two band pass filters. The design process involved the use of software such as ADS 2000A, Ansoft Designer and MathCad. FET FHX76 LP is used in the design of the LNA due to its low noise figure and high impedance input. As for the RFA design,FET EPA018A was used. The LNA and the RFA used T lumped reactive element network and microstrip line matching network. Two 3 dBπ -attenuators were inserted at the input and output of the RFA to isolate the system from the reflected load power. A Wilkinson power divider is developed for two equal power structures using impedance microstrip line technique. Microstrip technology was used for designing the Chebyshev filter. The result of each module for the front end is presented

Validation study of the Mini-Mental State Examination in a Malay-speaking elderly population in Malaysia

Background/Aims: In view of the differing sensitivity and specificity of the Mini-Mental State Examination (MMSE) in the non-English-speaking populations, we conducted the first validation study of the Malay version (M-MMSE) in Malaysia among 300 subjects (from the community and outpatient clinics). Methods: Three versions were used: M-MMSE-7(serial 7), M-MMSE-3 (serial 3) and M-MMSE-S (spell ‘dunia’backwards). Dementia was assessed using the criteria of the Diagnostic and Statistical Manual of Mental Disorders IV . The optimal cutoff scores were obtained from the receiver operating characteristics curves. Results: Seventy-three patients (24.3%) had dementia and 227 (75.7%) were controls. Three hundred patients completed the M-MMSE-7, 160 the MMMSE-3 and 145 the M-MMSE-S. All 3 versions were valid and reliable in the diagnosis of dementia. The optimal cutoff scores varied with each version and gender. In the control group, significant gender differences were observed in the patients with the lowest educational status. Increasing educational levels significantly improved the M-MMSE performance in both genders. Conclusion: All 3 versions of the M-MMSE are valid and reliable as a screening tool for dementia in the Malaysian population, but at different cutoff scores.In those with the lowest educational background, gender adjusted cutoff scores should be applied

Biochemical aspirin resistance in stroke patients - a cross-sectional single centre study

Aspirin use is known to reduce the recurrence of stroke. However, the clinical response to aspirin has been mixed. The rate of stroke recurrence whilst on aspirin treatment is still unacceptably high. A plausible explanation for this may be resistance to the effects of aspirin. The causes of aspirin resistance are manifold and multi-factorial. We conducted a study to investigate the prevalence rate of biochemical aspirin resistance in a cohort of aspirin-naïve stroke patients. We also sought to determine the inherent factors that may predispose towards the development of aspirin resistance. Method: This was a cross-sectional, observational study conducted on patients admitted to our centre with an acute stroke who were aspirin-naïve. The diagnosis of an acute stroke was confirmed by clinical history and brain imaging. Fifty consecutive patients were prospectively enrolled. Socio-demographic data were collected and baseline blood investigations were performed. Patients were tested for biochemical aspirin resistance using Multiplate® platelet analyser (Dynabyte, Munich, Germany) after 5 doses of aspirin, corresponding to a total dose of 900 mg. Results: The median age of patients was 65.5 years and 54 % of patients were female. There were 11 smokers; of these 10 were male. Twenty-six (52 %) patients were Chinese, 21 (41 %) were Malay and 3 (6.0 %) were Indian. Aspirin resistance was present in 14 % of our patients. There was an inverse relationship between the presence of aspirin resistance and plasma HDL levels (r = -0.394; p = 0.005). There was no relationship observed between aspirin resistance and total cholesterol, triglycerides, LDL, HbA1c, ALT, ALP, urea and creatinine levels. There were no significant differences in demographic profiles or smoking status between the aspirin resistant and non-aspirin resistant groups. We did not find any link between ethnicity and aspirin resistance. Conclusions: Our results indicate that a lower HDL level is associated with biochemical aspirin resistance. This may increase platelet aggregation and consequently increase the risk of a recurrent stroke. The clinical implications for aspirin resistance are far reaching. Any evidence that correctable factors may negatively influence the action of aspirin warrants further investigation. The prevalence rate of biochemical aspirin resistance in our study is comparable to the findings in other studies performed in an Asian population. Further research is required to determine how our findings translate into clinical aspirin resistance and stroke recurrence

Association of severe hypertension with pneumonia in elderly patients with acute ischemic stroke

Pneumonia is one of the most frequent complications in elderly patients with acute ischemic stroke. Although severe hypertension is often observed in the early phase of acute stroke, there are few studies of acute hypertension as a factor influencing the incidence of stroke-associated pneumonia (SAP) in elderly subjects with acute ischemic stroke. To assess the association of acute phase blood-pressure elevation with the incidence of SAP, we compared 10 elderly patients with acute ischemic stroke complicated with severe hypertension (⩾200/120 mm Hg) with 43 patients with moderate hypertension (160–199/100–119 mm Hg), as well as with 65 control normotensive or mildly hypertensive (<160/100 mm Hg) controls on admission. Data were collected on known risk factors, type of ischemic stroke and underlying chronic conditions. The significance of differences in risk factors was analyzed using univariate and multivariate comparisons of 38 SAP cases and others, 8 SAP death cases and others, and 28 patients with poor outcome associated with in-hospital death or artificial feeding at discharge and others. After adjustment for potential confounding factors, the relative risk estimates for SAP, SAP death and poor outcome were 2.83 (95% confidence interval 1.14–7.05), 5.20 (1.01–26.8) and 6.84 (1.32–35.4), respectively, for severe hypertension relative to normotensive or mildly hypertensive controls. We conclude that severe hypertension on admission is an independent predictive factor for SAP in elderly patients with acute ischemic stroke

Guidelines for management of ischaemic stroke and transient ischaemic attack 2008

This article represents the update of the European Stroke Initiative Recommendations for Stroke Management. These guidelines cover both ischaemic stroke and transient ischaemic attacks, which are now considered to be a single entity. The article covers referral and emergency management, Stroke Unit service, diagnostics, primary and secondary prevention, general stroke treatment, specific treatment including acute management, management of complications, and rehabilitation

Original Article - The Impact of Diabetes Mellitus on In-hospital Stroke Mortality

BACKGROUND AND PURPOSE: Diabetes mellitus is a strong risk factor for stroke. However, the prognosis in terms of mortality after a stroke is still unclear, especially in diabetic patients. The main purpose of this study was to compare and evaluate the features of stroke in patients having diabetes mellitus with those without diabetes mellitus and to identify factors that influence survival following a stroke. SUBJECTS AND METHODS: In a prospective hospital-based study consecutive patients with acute ischaemic stroke were enrolled. A single observer, using predefined diagnostic criteria recorded the demographics, risk factors and the type of stroke and deaths that occurred during the in-patient period. RESULTS: One hundred and sixty-three patients with acute ischaemic stroke were enrolled in the study. Type 2 diabetes mellitus was present in 90 (55.2%) patients. Diabetes was a significant independent predictor of mortality (OR 4.88; 95%CI 1.25-19.1). Among the diabetic patients middle cerebral artery (MCA) territory infarct (OR 34.8, 95%CI 4.5-269.4) and Glasgow coma score (GCS) less than 9 (OR 12.3, 95%CI 3.7-198.1) were independent predictors of mortality. CONCLUSIONS: MCA infarcts and poor conscious level increase the mortality in diabetic patients with stroke. Mortality is also significantly related to a high level of blood glucose at admission

ORIGINAL ARTICLE The Predictors of Subclinical Cerebral Infarcts in Ischaemic Stroke Patients

Subclinical cerebral infarcts (SCI) have been increasingly shown to cause a significant clinical impact. However, there are limited data available on Asian patients. The objectives of this study were to determine the prevalence of SCI in ischaemic stroke patients seen in the Hospital Universiti Kebangsaan Malaysia (HUKM) and to identify its associated risk factors. We evaluated the brain computed tomography (CT) evidence of subclinical infarcts in ischaemic stroke patients. The patients were selected from those who were on regular follow up in the neurology clinic following an ischaemic stroke. The risk factors associated with subclinical infarct were documented. The brain CTs were done during acute admission and reviewed for SCI. Sixty-one patients were enrolled in this study. Twenty-two (36.1%) out of the 61 patients had SCI. The risk factors for SCI in our study were hypertension (OR 14.16 CI 2.04-97.89), diabetes mellitus (OR 12.48; CI 1.95-79.77) and leukoaraiosis (OR 28.39; CI 2.33-284.16). Subclinical cerebral infarcts were present in about one third of our ischaemic stroke patients. This finding is higher than in previous studies done on Caucasians. Hypertension, diabetes mellitus and leukoaraiosis independently predict SCI