A sub-1 V, 26 μw, low-output-impedance CMOS bandgap reference with a low dropout or source follower mode

We present a low-power bandgap reference (BGR), functional from sub-1 V to 5 V supply voltage with either a low dropout (LDO) regulator or source follower (SF) output stage, denoted as the LDO or SF mode, in a 0.5-μm standard digital CMOS process with V tn≈ 0.6 V and |V tp| ≈ 0.7 V at 27 °C. Both modes operate at sub-1 V under zero load with a power consumption of around 26 μW. At 1 V (1.1 V) supply, the LDO (SF) mode provides an output current up to 1.1 mA (0.35 mA), a load regulation of ±8.5 mV/mA (±33 mV/mA) with approximately 10 μ s transient, a line regulation of ±4.2 mV/V (±50μV/V), and a temperature compensated reference voltage of 0.228 V (0.235 V) with a temperature coefficient around 34 ppm/° C from -20°C to 120 °C. At 1.5 V supply, the LDO (SF) mode can further drive up to 9.6 mA (3.2 mA) before the reference voltage falls to 90% of its nominal value. Such low-supply-voltage and high-current-driving BGR in standard digital CMOS processes is highly useful in portable and switching applications. © 2010 IEEE.published_or_final_versio

Vallecular cyst in a neonate

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Obstructive sleep apnoea syndrome presented as failure to thrive in a Down's syndrome child

Children suffering from Down's syndrome are prone to develop obstructive sleep apnoea syndrome (OSAS) due to craniofacial abnormalities, small upper airway, adenotonsillar hypertrophy and muscular hypotonia.1 OSAS will lead to various complications including failure to thrive.2 We report a Down's syndrome boy whose main presenting feature of OSAS was failure to thrive. He was successfully treated initially with nocturnal continuous positive airway pressure (CPAP) ventilation and subsequently with adenotonsillectomy.published_or_final_versio

Follow up of serial urea breath test results in patients after consumption of antibiotics for non-gastric infections

Aim: The widespread use of antibacterial therapy has been suggested to be the cause for the decline in the prevalence of Helicobacter pylori infection. This study examine the serial changes of urea breath test results in a group of hospitalized patients who were given antibacterial therapy for non-gastric infections. Methods: Thirty-five hospitalized patients who were given antibacterial therapy for clinical infections, predominantly chest and urinary infections, were studied. Most (91 %) patients were given single antibiotic of either a penicillin or cephalosporin group. Serial 13C-urea breath tests were performed within 24 hours of initiation of antibiotics, at one-week and at six-week post-therapy. H. pylori infection was diagnosed when one or more urea breath tests was positive. Results: All 35 patients completed three serial urea breath tests and 26 (74 %) were H. pylori-positive. Ten (38 %) H. pylori-infected patients had at least one negative breath test results during the study period. The medium delta 13C values were significantly lower at baseline (8.8) than at one-week (20.3) and six-week (24.5) post-treatment in H. pylori-positive individuals (P=0.022). Clearance of H. pylori at six-week was only seen in one patient who had received anti-helicobacter therapy from another source. Conclusion: Our results suggested that one-third of H. pylori-infected individuals had transient false-negative urea breath test results during treatment with antibacterial agent. However, clearance of H. pylori infection by regular antibiotic consumption is rare.published_or_final_versio

Inhaled foreign bodies: children with peanut in airway

Foreign body aspiration is a common problem in young children. Many patients present after a significant delay despite having a witnessed choking event. Moreover, their presentations may mimic other common respiratory problems like pneumonia or asthma. It is extremely important to be attentive to history taking and clinical signs that may indicate early bronchoscopy to confirm the diagnosis.published_or_final_versio

Parametric methods outperformed non-parametric methods in comparisons of discrete numerical variables

<p>Abstract</p> <p>Background</p> <p>The number of events per individual is a widely reported variable in medical research papers. Such variables are the most common representation of the general variable type called discrete numerical. There is currently no consensus on how to compare and present such variables, and recommendations are lacking. The objective of this paper is to present recommendations for analysis and presentation of results for discrete numerical variables.</p> <p>Methods</p> <p>Two simulation studies were used to investigate the performance of hypothesis tests and confidence interval methods for variables with outcomes {0, 1, 2}, {0, 1, 2, 3}, {0, 1, 2, 3, 4}, and {0, 1, 2, 3, 4, 5}, using the difference between the means as an effect measure.</p> <p>Results</p> <p>The Welch U test (the T test with adjustment for unequal variances) and its associated confidence interval performed well for almost all situations considered. The Brunner-Munzel test also performed well, except for small sample sizes (10 in each group). The ordinary T test, the Wilcoxon-Mann-Whitney test, the percentile bootstrap interval, and the bootstrap-<it>t </it>interval did not perform satisfactorily.</p> <p>Conclusions</p> <p>The difference between the means is an appropriate effect measure for comparing two independent discrete numerical variables that has both lower and upper bounds. To analyze this problem, we encourage more frequent use of parametric hypothesis tests and confidence intervals.</p

Snoring in primary school children and domestic environment: A Perth school based study

BACKGROUND: The home is the predominant environment for exposure to many environmental irritants such as air pollutants and allergens. Exposure to common indoor irritants including volatile organic compounds, formaldehyde and nitrogen dioxide, may increase the risk of snoring for children. The aim of this study was to investigate domestic environmental factors associated with snoring in children. METHODS: A school-based respiratory survey was administered during March and April of 2002. Nine hundred and ninety six children from four primary schools within the Perth metropolitan area were recruited for the study. A sub-group of 88 children aged 4–6 years were further selected from this sample for domestic air pollutant assessment. RESULTS: The prevalences of infrequent snoring and habitual snoring in primary school children were 24.9% and 15.2% respectively. Passive smoking was found to be a significant risk factor for habitual snoring (odds ratio (OR) = 1.77; 95% confidence interval (CI): 1.20–2.61), while having pets at home appeared to be protective against habitual snoring (OR = 0.58; 95% CI: 0.37–0.92). Domestic pollutant assessments showed that the prevalence of snoring was significantly associated with exposure to nitrogen dioxide during winter. Relative to the low exposure category (<30 μg/m(3)), the adjusted ORs of snoring by children with medium (30 – 60 μg/m(3)) and high exposures (> 60 μg/m(3)) to NO(2 )were 2.5 (95% CI: 0.7–8.7) and 4.5 (95% CI: 1.4–14.3) respectively. The corresponding linear dose-response trend was also significant (P = 0.011). CONCLUSION: Snoring is common in primary school children. Domestic environments may play a significant role in the increased prevalence of snoring. Exposure to nitrogen dioxide in domestic environment is associated with snoring in children

A 0.9V 2.7μW small-area 100μs+ analog CMOS tunable-delay circuit utilizing miller effect

We report a novel analog delay circuit based on Miller effect that features small die area and tunable delay in the order of 100μs, without using any external component. The delay time can be tuned by varying the biasing current, capacitor sizes, transconductance of the gain-stage transistor and the corresponding output impedances. The turn-on threshold of the delay circuit can also be raised, as required in some applications, by utilizing the body effect of the input transistors. The circuit has a very low startup voltage (≈0.9V) and consumes a very low power (≈2.7μW) in a standard 1 μm pure CMOS process with Vtn ≈ 0.65V and Vtp ≈ 0.8V at 25°C. Circuit operations are elaborated and its function is verified by simulation and silicon measurement. © 2008 IEEE.link_to_subscribed_fulltex

BP and arterial distensibility in children with primary snoring

Study objective: While previous studies have suggested an association between obstructive sleep apnea and cardiovascular complications, the effects of primary snoring in children on daytime systemic BP and arterial distensibility remain unknown. Design and patients: To determine the effects of primary snoring on BP and peripheral conduit artery distensibility, 30 children with primary snoring were studied at an age of 9.5 ± 2.8 years (mean ± SD). Systemic BP was measured using an automated device, while brachioradial arterial distensibility was assessed by measuring pulse wave velocity (PWV), which is inversely related to the square root of distensibility. The results were compared to those of 30 healthy control subjects matched for age, sex, and body size. Results: As compared to control subjects, children with primary snoring had significantly higher systolic BP (112 ± 10 mm Hg vs 105 ± 8 mm Hg, p = 0.001), diastolic BP (60 ± 7 mm Hg vs 53 ± 9 mm Hg, p = 0.004), and mean BP (81 ± 7 mm Hg vs 71 ± 8 mm Hg, p < 0.001). Likewise, those with primary snoring had significantly higher PWV (9.7 ± 1.6 m/s vs 7.9 ± 2.0 m/s, p = 0.001). Multiple regression identified age, body mass index (BMI), and primary snoring as significant determinants of systemic BP; however, primary snoring is the only significant determinant of PWV. Regardless of the BMI, systemic BP and PWV remained significantly higher in children with primary snoring. Conclusion: Children with primary snoring have increased daytime systemic BP and reduced arterial distensibility, which may jeopardize long-term cardiovascular health.link_to_subscribed_fulltex

A 30 μ W CMOS bandgap reference featuring a 1.5-6 mA output driving current and a Miller-effect startup circuit

We present a pure CMOS bandgap voltage reference with a low quiescent current and high output current driving capability. The circuit sources a driving current of up to 1.5 mA with the reference voltage kept above 98.5% of its designated 1.2 V, and up to 6 mA before the voltage drops to 90%. The circuit achieves a very low supply current of 13 μ A, a low power of 30 μ W, a line regulation of ± 2.5 mV / V and a load regulation of ± 7 mV / mA. The reference is implemented in a 1 μ m pure CMOS process with Vtn ≈ | Vtp | ≈ 0.7 V at 25 {ring operator} C using substrate pnp. A startup circuit, which shuts down itself after a controlled delay using Miller effect, is also introduced. By utilizing the body effect of the input transistors, the turn-on threshold of the startup circuit is raised to about 1 V, making it a perfect match for the reference architecture. Silicon measurements are in good agreement with simulations. © 2009 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex