Inductance calculations of printed windings of power transformers using partial inductance method

The method of printed windings of transformer-windings are printed on a printed circuit board (PCB) and all windings are embedded in a stack of these PCBs is a promising way in controlling the windings' shape and air spacing in a fixed pattern; it eliminates the parameter variations in a great deal. The partial inductance method gives an easy and accurate approach to calculate loop inductance by the generalised partial inductance, which is derived from dividing the whole loop into finite length of elements. Self and mutual inductance are the summation of inductance contributed from individual elements. This is useful in predicting the leakage inductance which has been the most undesirable parameter in PWM converter. And this method can also be applied to transformers in resonant converters in which inductances have to be accurately controlled.published_or_final_versio

A novel soft-switching double modulation converter (DMC)

This paper introduces a new and simple power converter topology by which both the amplitude and the duty cycle are modulated to achieve soft switching characteristic in a standard half bridge configuration. This novel double modulation power converter (DMC) is able to provide zero voltage switching and nonpulsating input ripple current. Constant switching frequency, simple control and gate drive circuit makes the DMC an ideal power converter to fill the low to medium power application gap in which the soft switching phase modulation method is costly to apply. The DMC is also applicable to full bridge circuits for higher power output. An offline 1 MHz 50 W DMC is built which demonstrates the high efficiency and the compactness of the power converter.published_or_final_versio

Metastatic carcinoma of breast in the urinary bladder

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Design and analysis of discontinuous mode series resonant converter

This paper aims at designing a low power, off-line, high efficiency, complex in size, twin-capacitors half-bridge series resonant converter. It gives steps by steps design procedures of the discontinuous mode series resonant converter starting from power stage circuit design to feedback loop control design. The small signal analysis is based on the injected-absorbed current method.published_or_final_versio

Validation of the Abbreviated Mental Test (Hong Kong version) in the elderly medical patient

The Abbreviated Mental Test is a useful screening test for abnormal cognitive function in the elderly patient. It is widely used in UK geriatrics practice. A modified local version of the Abbreviated Mental Test is also commonly used in Hong Kong. In the present study, the local version of the 10-question Abbreviated Mental Test was validated against clinical diagnoses of normal/abnormal cognitive function (by DSM III R criteria). Sixty-nine patients (aged 65 years and older) referred to the Acute Geriatric Assessment Team at the Queen Mary Hospital were assessed. Nine patients (13%) were excluded because of language barrier, deafness, dysphasia and/or severe dysarthria. Sixty patients completed the test and the clinical assessment. An incorrect answer in each of the test items was found to be significantly associated with abnormal cognitive function (P<0.005). For the Abbreviated Mental Test score, the best cut-off point was found to be six (below six was considered abnormal); this yielded a sensitivity of 96% and a specificity of 94%.published_or_final_versio

Molecular-beam epitaxy of topological insulator Bi2Se3 (111) and (221) thin films

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Multirate Kalman filtering approach for optimal two-dimensional signal reconstruction from noisy subband systems

The International Conference on Image Processing, Santa Barbara, California, 26-29 October 1997Conventional synthesis filters in subband systems lose their optimality when additive noise due, for example, to signal quantization, disturbs the subband components. The multichannel representation of subband signal is combined with the statistical model of input signal to derive the multirate state-space model for filter bank system with additive noises. Thus the signal reconstruction problem in subband system can be formulated as the process of optimal state estimation in the equivalent multirate state-space model. With the input signal embedded in the state vector, the multirate Kalman filtering provides the minimum-variance reconstruction of input signal. Using the powerful Kronecker product notation, the results and derivations can then be extended to the 2-D cases. Incorporated with the vector dynamical model, the 2-D multirate state-space model for 2-D Kalman filtering is developed. Computer simulation with the proposed 2-D multirate Kalman filter gives favorable results.published_or_final_versio

Strain in epitaxial Bi2Se3 grown on GaN and graphene substrates: A reflection high-energy electron diffraction study

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Predictive factors for extracorporeal shockwave lithotripsy success in ureteric stones, does skin-stone distance and hounsfield unit matter?

OBJECTIVE: To evaluate the usefulness of measuring stone skin distance and stone attenuation values by non-contrast computed tomography for predicting treatment outcome of ureteric stones by extracorporeal shockwave lithotripsy (ESWL). PATIENT AND METHOD : Retrospective review of 66 patients who underwent ESWL for ureteric stones with pre-ESWL NCCT in 2010–2012. Subjects were stratified into 2 groups, successful ESWL and failed ESWL, with ESWL success defined as stone fragment less than 4 mm at 6 weeks after ESWL. Patient age, sex, stone size, stone location, laterality, shockwave energy, number of shockwave administered, Hounsfield unit (HU), skin to stone distance (SSD), presence of hydronephrosis, pre-ESWL JJ stent or PCN were studied as predictive factors. RESULTS : Patient demographics and stone characteristics were similar between the 2 groups. On univariate analysis, the mean stone size for successful ESWL was 7.9 mm compared with 10.2 mm in the failure group (P = 0.02). For the skin-stone distance, the mean distance for the successful group was 95 mm compared with 104 mm in the failure group (P = 0.04). Concerning the Hounsfield Unit, a mean of 1034 HU was found in the successful compared with 1129 HU in the failure group (P = 0.16) CONCLUSION : Skin to stone distance on non-contrast CT scan is a useful predictive factors for ESWL success for ureteric stones.postprin

Continuation of dabigatran therapy in "real-world" practice in Hong Kong

Background: Dabigatran, an oral direct thrombin inhibitor, possesses several advantages over warfarin that can in principle simplify the management of stroke prevention in atrial fibrillation (AF). Nonetheless it remains unclear whether these advantages can translate to clinical practice and encourage long-term therapy. The objective was to describe long-term dabigatran therapy for stroke prevention in AF and to identify risk factors for discontinuation of therapy. Methods and Results: We studied 467 consecutive Chinese patients (72±11 years, male: 53.8%) with a mean CHA2DS2-VASc score of 3.6 prescribed dabigatran for stroke prevention in AF from March 2010 to September 2013. Over a mean follow-up of 16 months, 101 patients (21.6%) permanently discontinued dabigatran. The mean time-to-discontinuation was 8 months. The most common reason for discontinuation was dyspepsia (30.7%), followed by other adverse events (17.8%) such as minor bleeding (8.9%), major gastrointestinal bleeding (7.9%), and intracranial hemorrhage (1%). Other reasons included dosing frequency (5.9%), fear of side effects (4.0%), lack of laboratory monitoring (1.0%), and cost (1.0%). Multivariable analysis revealed that low baseline estimated glomerular filtration rate (p = 0.02), absence of hypertension (p= 0.01), and prior use of a proton-pump inhibitor (p = 0.02) and H2-receptor blocker (p = 0.01) were independent predictors of drug discontinuation. In addition, there were altogether 9 ischemic strokes (1.5%/years), 3 intracranial hemorrhages (0.5%/year), and 24 major gastrointestinal bleedings (4.1%/year). Conclusion: Dabigatran discontinuation is very common amongst Chinese AF patients. This reveals a management gap in the prevention of stroke in AF. © 2014 Ho et al.published_or_final_versio