Management of severe aortic valve stenosis in the neonate

Aortic valve stenosis (AS) causing obstruction to the left ventricular outfl ow, and hence reduction of the cardiac output, remains a therapeutic challenge for paediatric cardiologists and cardiothoracic surgeons. Infants that present at birth may have very dysplastic valves with severe or critical AS and are typically the most diffi cult to treat. This article therefore focuses on the managementof severe AS in the neonate. This article also revises the embryology of the semi-lunar valves, as the morphology of the aortic valve often dictates the treatment pathway

ICA vs. PCA Active Appearance Models: Application to Cardiac MR Segmentation

Abstract. Statistical shape models generally use Principal Component Analysis (PCA) to describe the main directions of shape variation in a training set of ex-ample shapes. However, PCA has the restriction that the input data must be drawn from a Gaussian distribution and is only able to describe global shape variations. In this paper we evaluate the use of an alternative shape decomposi-tion, Independent Component Analysis (ICA), for two reasons. ICA does not require a Gaussian distribution of the input data and is able to describe localized shape variations. With ICA however, the resulting vectors are not ordered, therefore a method for ordering the Independent Components is presented in this paper. To evaluate ICA-based Active Appearance Models (AAMs), 10 leave-15-out models were trained on a set of 150 short-axis cardiac MR Images with PCA-based as well as ICA-based AAMs. The median values for the aver-age and maximal point-to-point distances between the expert drawn and auto-matically segmented contours for the PCA-based AAM were 2.95 and 8.39 pix-els. For the ICA-based AAM these distances were 1.86 and 5.01 pixels respec-tively. From this, we conclude that the use of ICA results in a substantial im-provement in border localization accuracy over a PCA-based model.

Management of severe aortic valve stenosis in the neonate

Aortic valve stenosis (AS) causing obstruction to the left ventricular outfl ow, and hence reduction of the cardiac output, remains a therapeutic challenge for paediatric cardiologists and cardiothoracic surgeons. Infants that present at birth may have very dysplastic valves with severe or critical AS and are typically the most diffi cult to treat. This article therefore focuses on the management of severe AS in the neonate. This article also revises the embryology of the semi-lunar valves, as the morphology of the aortic valve often dictates the treatment pathway.http://www.saheart.org/journal/index.php?journal=SAHJam201

Pathogenesis of distal renal tubular acidosis

Distal renal tubular acidosis (RTA) is a syndrome characterized by hyperchloremic metabolic acidosis and an inappropriately high urine pH relative to the degree of acidosis. The clinical presentation is frequently complicated by nephrocalcinosis, hypercalciuria, and nephrolithiasis. Less frequent presenting manifestations include hypokalemia and osteomalacia (for review of clinical features, see Refs. 1–4). Initially, all cases of renal tubular acidosis were considered to have similar pathophysiologic mechanisms, but subsequent studies have subdivided the group into abnormalities of bicarbonate reabsorption (proximal RTA), disorders of net acid excretion (distal or classical), and defects of ammonium production. In the present review, we will limit our discussion to the pathogenesis of distal RTA

Parity Problem With A Cellular Automaton Solution

The parity of a bit string of length $N$ is a global quantity that can be efficiently compute using a global counter in ${O} (N)$ time. But is it possible to find the parity using cellular automata with a set of local rule tables without using any global counter? Here, we report a way to solve this problem using a number of $r=1$ binary, uniform, parallel and deterministic cellular automata applied in succession for a total of ${O} (N^2)$ time.Comment: Revtex, 4 pages, final version accepted by Phys.Rev.

Continuous-wave and passively Q -switched cladding-pumped planar waveguide lasers

Greater than 12W of average output power has been generated from a diode-pumped YbYAG cladding-pumped planar waveguide laser. The laser radiation developed is linearly polarized and diffraction limited in the guiding dimension. A slope efficiency of 0.5WW with a peak optical optical conversion efficiency of 0.31WW is achieved. In a related structure, greater than 8W of Q -switched average output power has been generated from a NdYAG cladding-pumped planar waveguide laser by incorporation of a Cr 4+ YAG passive Q switch monolithically into the waveguide structure. Pulse widths of 3ns and pulse-repetition frequencies as high as 80kHz have been demonstrated. A slope efficiency of 0.28WW with a peak optical optical conversion efficiency of 0.21WW is achieved

CW and passively Q-switched double-clad planar waveguide lasers

Greater than 12 W of average output power have been generated from a diode pumped Yb:YAG cladding-pumped planar waveguide laser. The developed laser radiation is linearly polarized and diffraction limited in the guiding dimension. A slope efficiency of 0.5 W/W with a peak optical-optical conversion efficiency of 0.31 W/W is achieved. In a related structure, greater than 8 W of Q-switched average output power has been generated from a Nd:YAG cladding-pumped planar waveguide incorporating Cr:YAG passive Q-switch monolithically into the waveguide structure. Pulse widths of 3 nsec and PRFs as high as 80 kHz have been demonstrated. A slope efficiency of 0.28 W/W with a peak optical-optical conversion efficiency of 0.21 W/W is achieved

Effect of resistance exercise dose components for tendinopathy management: a systematic review with meta-analysis.

The objective of this study was to investigate potential moderating effects of resistance exercise dose components - including intensity, volume and frequency - for the management of common tendinopathies. The study was conducted through a systematic review with meta-analysis and meta-regressions, using sources that included (but were not limited to) MEDLINE, CINAHL, SPORTDiscus, ClinicalTrials.gov and the ISRCTN Registry. Selection criteria were based on randomised and non-randomised controlled trials investigating resistance exercise as the dominant treatment class, reporting sufficient information regarding two or more components of exercise dose. A total of 110 studies were included in meta-analyses (148 treatment arms (TAs), 3953 participants), reporting on five tendinopathy locations (rotator cuff: 48 TAs; Achilles: 43 TAs; lateral elbow: 29 TAs; patellar: 24 TAs; gluteal: 4 TAs). Meta-regressions provided consistent evidence of greater pooled mean effect sizes for higher intensity therapies comprising additional external resistance compared to body mass only (large effect size domains: βBodyMass:External = 0.50 [95% CrI: 0.15 to 0.84; p = 0.998]; small effect size domains βBodyMass:External = 0.04 [95% CrI: -0.21 to 0.31; p = 0.619]) when combined across tendinopathy locations or analysed separately. Greater pooled mean effect sizes were also identified for the lowest frequency (less than daily) compared with mid (daily) and high frequencies (more than once per day) for both effect size domains, when combined or analysed separately (p ≥ 0.976). Evidence for associations between training volume and pooled mean effect sizes was minimal and inconsistent. The study found that resistance exercise dose is poorly reported within tendinopathy management literature. However, this large meta-analysis identified some consistent patterns indicating greater efficacy on average with therapies prescribing higher intensities (through inclusion of additional loads) and lower frequencies, potentially creating stronger stimuli and facilitating adequate recovery