Central sleep-disordered breathing and the effects of oxygen therapy in infants with Prader-Willi syndrome

OBJECTIVES

To describe breathing patterns in infants with Prader-Willi Syndrome (PWS), as well as the effects of supplemental oxygen (O2) on breathing patterns. Children with PWS commonly have sleep-disordered breathing, including hypersomnolence and obstructive sleep apnoea, as well as central sleep breathing abnormalities that are present from infancy.

DESIGN

Retrospective cohort study.

PATIENTS

Infants with a diagnosis of PWS.

SETTING

Tertiary children's hospital.

INTERVENTIONS

Infants with PWS underwent full polysomnography, and in those with frequent desaturations associated with central events, supplemental O2 during sleep was started and followed with regular split-night studies (periods in both air and O2).

RESULTS

Thirty split-night studies on 10 infants (8 female) aged 0.06-1.79 (median 0.68, IQR 0.45, 1.07) years were undertaken. At baseline (ie, air), children with PWS had a median (IQR) central apnoea index (CAI) of 4.7 (1.9, 10.6) per hour, with accompanying falls in oxygen saturation (SpO2). O2 therapy led to statistically significant reductions in CAI to 2.5/hour (p=0.002), as well as a reduced central event index (CEI) and improved SpO2. No change in the number of obstructive events was noted. Central events were more prevalent in rapid-eye movement/active sleep.

CONCLUSIONS

It is concluded that infants with PWS may have central sleep-disordered breathing, which, in some children, may cause frequent desaturations. Improvements in CAI and CEI as well as oxygenation were noted with O2 therapy. Longitudinal work with this patient group would help to establish the timing of onset of obstructive symptoms.

Pyridoxine-dependent epilepsy owing to antiquitin deficiency--mutation in the ALDH7A1 gene

Pyridoxine-dependent epilepsy (PDE) is an inborn error of metabolism resulting from antiquitin deficiency. There is marked elevation of α-amino adipic semi-aldehyde (αAASA), piperidine-6-carboxylate (P6C) and pipecolic acid. The diagnosis can be confirmed by identifying the mutation in the ALDH7A1 gene in chromosome 5q3l. An 8-year-old Indian girl presented with severe developmental delay and seizures and was found to have pyridoxine-dependent epilepsy owing to an antiquitin mutation. Genetic evaluation of the parents allowed antenatal diagnosis to be made during the next pregnancy.

Thermal performance of higher aspect ratio microchannels using TiO2-water nanofluids

An experimental setup was developed to study the heat transfer and fluid flow characteristics in rectangular copper microchannels with hydraulic diameter 29.4 microm using TiO2-Water nanofluids. The experimental facility is validated using existing correlations and subsequently tested with 0.1% and 0.3% concentrations of TiO2 nanofluids. The thermal resistance of heat sink with nanofluids is compared with the base fluid. It is inferred that 0.3% TiO2-Water nanofluids have 18% lower thermal resistance as compared to base fluid having for the same operating conditions.

Sequential projection-based metacognitive learning in a radial basis function network for classification problems

In this paper, we present a sequential projection-based metacognitive learning algorithm in a radial basis function network (PBL-McRBFN) for classification problems. The algorithm is inspired by human metacognitive learning principles and has two components: a cognitive component and a metacognitive component. The cognitive component is a single-hidden-layer radial basis function network with evolving architecture. The metacognitive component controls the learning process in the cognitive component by choosing the best learning strategy for the current sample and adapts the learning strategies by implementing self-regulation. In addition, sample overlapping conditions and past knowledge of the samples in the form of pseudosamples are used for proper initialization of new hidden neurons to minimize the misclassification. The parameter update strategy uses projection-based direct minimization of hinge loss error. The interaction of the cognitive component and the metacognitive component addresses the what-to-learn, when-to-learn, and how-to-learn human learning principles efficiently. The performance of the PBL-McRBFN is evaluated using a set of benchmark classification problems from the University of California Irvine machine learning repository. The statistical performance evaluation on these problems proves the superior performance of the PBL-McRBFN classifier over results reported in the literature. Also, we evaluate the performance of the proposed algorithm on a practical Alzheimer's disease detection problem. The performance results on open access series of imaging studies and Alzheimer's disease neuroimaging initiative datasets, which are obtained from different demographic regions, clearly show that PBL-McRBFN can handle a problem with change in distribution.

Nanometer-scale, quantitative composition mappings of InGaN layers from a combination of scanning transmission electron microscopy and energy dispersive x-ray spectroscopy

Using elastic scattering theory we show that a small set of energy dispersive x-ray spectroscopy (EDX) measurements is sufficient to experimentally evaluate the scattering function of electrons in high-angle annular dark field scanning transmission microscopy (HAADF-STEM). We then demonstrate how to use this function to transform qualitative HAADF-STEM images of InGaN layers into precise, quantitative chemical maps of the indium composition. The maps obtained in this way combine the resolution of HAADF-STEM and the chemical precision of EDX. We illustrate the potential of such chemical maps by using them to investigate nanometer-scale fluctuations in the indium composition and their impact on the growth of epitaxial InGaN layers.

Automated region mask for four-chamber fetal heart biometry

This letter proposes an automated region mask for the detection of cardiac chambers from ultrasonic fetal heart biometry. The fetal biometry consists of two dimensional ultrasonic cine-loop sequences of apical four chamber view of fetal heart, which are comparatively The clinical motion information of individual frame is extracted by keeping a constant frame rate of 25 frames per second (fps). The region mask is designed based on the superimposition of motion information from a set of consecutive frames that belong to one cardiac cycle followed by connected component labelling. The borders and edges of all four chambers are thus recognized leading to formation of binary region mask. Experimental study based on second trimester cine-loop sequences confirms the suitability of the proposed technique for detection of heart chambers.

Prosthetic rehabilitation of a patient with enucleated eye - a case report

BACKGROUND

The loss of an eye has a crippling effect on the psychology of the patient, making rehabilitation process challenging for both doctor and patient.

OBJECTIVE

To report a case of anophthalmic socket with prosthetic rehabilitation in a cost effective manner.

CASE

A 32-year-old female presented with anophthalmic socket for prosthetic rehabilitation. A custom made ocular prosthesis was implanted successfully.

CONCLUSION

The custom made ocular prosthesis is simple, affordable and can be carried out in a small clinical set-up and provides a superior natural appearance.

Metacognitive Learning in a Fully Complex-Valued Radial Basis Function Neural Network

Recent studies on human learning reveal that self-regulated learning in a metacognitive framework is the best strategy for efficient learning. As the machine learning algorithms are inspired by the principles of human learning, one needs to incorporate the concept of metacognition to develop efficient machine learning algorithms. In this letter we present a metacognitive learning framework that controls the learning process of a fully complex-valued radial basis function network and is referred to as a metacognitive fully complex-valued radial basis function (Mc-FCRBF) network. Mc-FCRBF has two components: a cognitive component containing the FC-RBF network and a metacognitive component, which regulates the learning process of FC-RBF. In every epoch, when a sample is presented to Mc-FCRBF, the metacognitive component decides what to learn, when to learn, and how to learn based on the knowledge acquired by the FC-RBF network and the new information contained in the sample. The Mc-FCRBF learning algorithm is described in detail, and both its approximation and classification abilities are evaluated using a set of benchmark and practical problems. Performance results indicate the superior approximation and classification performance of Mc-FCRBF compared to existing methods in the literature.

Amido-modified polylactide for potential tissue engineering applications

Poly(ester amide) copolymers based on L-lactide (2) and a new depsipeptide (1) were prepared by ring opening polymerization in the presence of Sn(Oct)2 as the catalyst. Variable monomer feed ratios up to 2.3 mol% 1 afforded copolymers containing ester and amido functional groups in the backbone. Lower glass transition temperatures and reduced crystallization kinetics and crystallinity compared to homo-polylactide (PLA) was achieved with low levels of amido incorporation. A reactivity comparison between enchainment of 2 and 1 was determined using in situ infrared spectroscopy. An increase in shear viscosity was observed with the increase of 1 content as determined by rheology studies. Cellular compatibility of the co-polymers was investigated by seeding D1 mouse stem cells onto films and characterizing cell morphology by optical microscopy. Preliminary results indicate that these novel materials exhibit reduced cell attachment compared to PLA and, pending further exploration, may have potential use in biomedical applications.