Water intoxication presenting as maternal and neonatal seizures: a case report.

Introduction We present an unusual case of fitting in the mother and newborn child, and the challenges faced in the management of their hyponatraemia due to water intoxication. Case presentation A previously well 37-year-old, primigravid Caucasian woman presented with features mimicking eclampsia during labour. These included confusion, reduced consciousness and seizures but without a significant history of hypertension, proteinuria or other features of pre-eclampsia. Her serum sodium was noted to be low at 111 mmol/litre as was that of her newborn baby. She needed anti-convulsants with subsequent intubation to stop the fitting and was commenced on a hypertonic saline infusion with frequent monitoring of serum sodium. There is a risk of long-term neurological damage from central pontine myelinolysis if the hyponatraemia is corrected too rapidly. Mother and baby went on to make a full recovery without any long-term neurological complications. Conclusion There is little consensus on the treatment of life-threatening hyponatraemia. Previous articles have outlined several possible management strategies as well as their risks. After literature review, an increase in serum sodium concentration of no more than 8–10 mmol/litre in 24 hours is felt to be safe but can be exceeded with extreme caution if life-threatening symptoms do not resolve. Formulae exist to calculate the amount of sodium needed and how much hypertonic intravenous fluid will be required to allow safer correction. We hypothesise the possible causes of hyponatraemia in this patient and underline its similarity in symptom presentation to eclampsia

Additions to the Vascular Flora of the Santa Ana Mountains, California

The Santa Ana Mountains, part of the Peninsular Ranges of southern California, have been welldocumented floristically. Nevertheless, since publication of a preliminary vascular flora for the range in 1978, a significant number of additions have been reported. These are principally from studies of two subregions in the southern portion of the range and include 42 taxa from the Santa Rosa Plateau and 88 taxa from the San Mateo Canyon Wilderness Area. Documentation is provided here for an additional 66 taxa not included in other published floristic accounts of the Santa Ana Mountains. A voucher specimen and generalized distribution information are cited for each taxon

Strain balancing of self-assembled InAs/GaAs quantum dots grown by metal-organic vapour phase epitaxy

In this thesis, the strain balancing of self-assembled InAs/GaAs quantum dots (QDs), grown by metal-organic vapour phase epitaxy (MOVPE) is investigated. Initially, the optimisation of the important QD growth parameters, InAs coverage, growth rate, V/III ratio during the QD growth and the V/III ratio during the capping layer growth is explored. Incorporation of a strain-balancing layer will allow the close vertical stacking of QD layers, giving the potential for increased volumetric QD density and hence increased optical gain. Strain balancing can only be achieved practically using a GaAszP1-z layer. Therefore, modelling is performed of different phosphorus concentrations to understand the effects of placing a large potential barrier between QD layers on the electrical characteristics and the lasing threshold current density. In addition, X-ray diffraction (XRD) spectra are modelled to estimate the thickness of GaAs0.8P0.2 required to strain balance a QD layer. Based on this modelling, the implementation of a strain-balancing layer, which does not adversely affect the electrical characteristics and threshold current density, was attempted for three different QD layer separations: 50, 30 and 20 nm. Incorporation of this layer is shown to improve the performance of a device with a 30 nm spacing between QD layers, although performance is still inferior to that of a 50 nm device without strain balancing. Successful laser fabrication of the 50 and 30 nm structures with strain balancing gave laser operation up to 240 and 200 K, respectively. Further optimisation of the QD growth resulted in a room temperature laser with a layer separation of 50 nm, however, this was without the strain-balancing layer. Modelling of a relatively new type of semiconductor laser structure, a photonic crystal surface emitting laser (PCSEL) is performed to develop the incorporation of QDs. Three material systems for the photonic crystal are considered: void/GaAs, InGaP/GaAs and AlAs/GaAs, where the potential performance of each material system is discussed and compared. Preliminary investigations of the effect of the overgrowth temperature on the QD emission and the effect of incorporating an AlAs layer on the electrical characteristics were performed

Towards Understanding Photodegradation Pathways in Lignins:The Role of Intramolecular Hydrogen Bonding in Excited States

The photoinduced dynamics of the lignin building blocks syringol, guaiacol, and phenol were studied using time-resolved ion yield spectroscopy and velocity map ion imaging. Following irradiation of syringol and guaiacol with a broad-band femtosecond ultraviolet laser pulse, a coherent superposition of out-of-plane OH torsion and/or OMe torsion/flapping motions is created in the first excited 1ππ* (S1) state, resulting in a vibrational wavepacket, which is probed by virtue of a dramatic nonplanar → planar geometry change upon photoionization from S1 to the ground state of the cation (D0). Any similar quantum beat pattern is absent in phenol. In syringol, the nonplanar geometry in S1 is pronounced enough to reduce the degree of intramolecular H bonding (between OH and OMe groups), enabling H atom elimination from the OH group. For guaiacol, H bonding is preserved after excitation, despite the nonplanar geometry in S1, and prevents O–H bond fission. This behavior affects the propensities for forming undesired phenoxyl radical sites in these three lignin chromophores and provides important insight into their relative “photostabilities” within the larger biopolymer

Chandra Imaging of the Gamma-Ray Source GeV J1809-2327

We report on Chandra imaging observations of the Galactic Unidentified $\gamma$-ray source GEV J1809-2327, comparing the X-ray images with new VLA 1.46 GHz and 4.86 GHz maps. The X-ray images reveal a point source connected to a non-thermal X-ray/radio nebula, supporting a pulsar/wind model for the $\gamma$-ray emitter. We also detect numerous X-ray sources from the young stellar association in the adjacent HII region S32.Comment: to appear in ApJ letter

A Pseudo-Two-Dimensional (P2D) Model for FeS2 Conversion Cathode Batteries

Conversion cathode materials are gaining interest for secondary batteries due to their high theoretical energy and power density. However, practical application as a secondary battery material is currently limited by practical issues such as poor cyclability. To better understand these materials, we have developed a pseudo-two-dimensional model for conversion cathodes. We apply this model to FeS2 - a material that undergoes intercalation followed by conversion during discharge. The model is derived from the half-cell Doyle-Fuller-Newman model with additional loss terms added to reflect the converted shell resistance as the reaction progresses. We also account for polydisperse active material particles by incorporating a variable active surface area and effective particle radius. Using the model, we show that the leading loss mechanisms for FeS2 are associated with solid-state diffusion and electrical transport limitations through the converted shell material. The polydisperse simulations are also compared to a monodisperse system, and we show that polydispersity has very little effect on the intercalation behavior yet leads to capacity loss during the conversion reaction. We provide the code as an open-source Python Battery Mathematical Modelling (PyBaMM) model that can be used to identify performance limitations for other conversion cathode materials

Characterization of optical properties of ZnO nanoparticles for quantitative imaging of transdermal transport

Widespread applications of ZnO nanoparticles (NP) in sun-blocking cosmetic products have raised safety concerns related to their potential transdermal penetration and resultant cytotoxicity. Nonlinear optical microscopy provides means for high-contrast imaging of ZnO NPs lending in vitro and in vivo assessment of the nanoparticle uptake in skin, provided their nonlinear optical properties are characterized. We report on this characterization using ZnO NP commercial product, Zinclear, mean-sized 21 nm. Two-photon action cross-section of this bandgap material (Ebg = 3.37 eV, λbg = 370 nm) measured by two techniques yielded consistent results of ηZnOσZnO(2ph) = 6.2 ± 0.8 μGM at 795 nm, and 32 ± 6 μGM at 770 nm per unit ZnO crystal cell, with the quantum efficiency of ηZnO = (0.9 ± 0.2) %. In order to demonstrate the quantitative imaging, nonlinear optical microscopy images of the excised human skin topically treated with Zinclear were acquired and processed using σZnO(2ph) and ηZnOvalues yielding nanoparticle concentration map in skin. Accumulations of Zinclear ZnO nanoparticles were detected only on the skin surface and in skin folds reaching concentrations of 800 NPs per μm3

Thin film notch filters as platforms for biological image processing

Many image processing operations involve the modification of the spatial frequency content of images. Here we demonstrate object-plane spatial frequency filtering utilizing the angular sensitivity of a commercial spectral bandstop filter. This approach to all-optical image processing is shown to generate real-time pseudo-3D images of transparent biological and other samples, such as human cervical cancer cells. This work demonstrates the potential of non-local, non-interferometric approaches to image processing for uses in label-free biological cell imaging and dynamical monitoring.Comment: manuscript 14 pages, 5 figures, supplementary material 7 pages, 4 supplementary figure