1,029 research outputs found

    The management of gestational diabetes

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    The incidence of gestational diabetes is increasing. As gestational diabetes is associated with adverse pregnancy outcomes, and has long-term implications for both mother and child, it is important that it is recognized and appropriately managed. This review will examine the pharmacological options for the management of gestational diabetes, as well as the evidence for blood glucose monitoring, dietary and exercise therapy. The medical management of gestational diabetes is still evolving, and recent randomized controlled trials have added considerably to our knowledge in this area. As insulin therapy is effective and safe, it is considered the gold standard of pharmacotherapy for gestational diabetes, against which other treatments have been compared. The current experience is that the short acting insulin analogs lispro and aspart are safe, but there are only limited data to support the use of long acting insulin analogs. There are randomized controlled trials which have demonstrated efficacy of the oral agents glyburide and metformin. Whilst short-term data have not demonstrated adverse effects of glyburide and metformin on the fetus, and they are increasingly being used in pregnancy, there remain long-term concerns regarding their potential for harm

    GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

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    Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga0.35In0.65N0.02As0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained

    Quality of ultrasound biometry obtained by local health workers in a refugee camp on the Thai-Burmese border.

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    Objective: In a refugee camp on the Thai–Burmese border, accurate dating of pregnancy relies on ultrasound measurements obtained by locally trained health workers. The aim of this study was to substantiate the accuracy of fetal biometry measurements performed by locally trained health workers by comparing derived reference equations with those published for Asian and European hospitals. Methods: This prospective observational study included 1090 women who had a dating crown–rump length (CRL) scan and one study-appointed ultrasound biometry scan between 16 and 40 weeks of gestation. The average of two measurements of each of biparietal diameter, head circumference, abdominal circumference and femur length was used in a polynomial regression model for the mean and SD against gestational age (GA). The biometry equations obtained were compared with published equations of professional sonographers from Asian and European hospitals by evaluation of the SD and Z-scores of differences between models. Results: Reference equations of biometric parameters were found to fit cubic polynomial models. The observed SD values, for any given GA, of fetal biometric measurements obtained by locally trained health workers were lower than those previously reported by centers with professional sonographers. For nearly the entire GA range considered, the mean values of the Asian and European equations for all four biometric measurements were within the 90% expected range (mean ± 1.645 SD) of our equations. Conclusion: Locally trained health workers in a refugee camp on the Thai–Burmese border can obtain measurements that are associated with low SD values and within the normal limits of published Asian and European equations. The fact that the SD values were lower than in other studies may be explained by the use of the average of two measurements, CRL dating or motivation of the locally trained sonographer

    Hong Kong Zhuhai Macao Link

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    AbstractThe Hong Kong Zhuhai Macao Link will be built across the mouth of the Pearl River Delta linking Hong Kong, Zhuhai and Macao in the south of China. The link will comprise of a dual 3-lane with hardshoulder motorway with a total length of approximately 42km, of which approximately 30km will be in mainland territory and approximately 12km will be within Hong Kong territory. The link will comprise of Border Crossing Facilities on reclaimed land in Zhuhai and Hong Kong, approximately 30km of sea-crossing bridges, approximately 5km of immersed tunnel, two artificial islands, approximately 2km of at-grade road and approximately 2km of cut and cover tunnel. The preliminary design of the link on the mainland side has been carried out by a joint venture of HPDI+ARUP+COWI+SHTDI+FHCL and on the Hong Kong side by ARUP alone. The division of work is as follows:•HPDI-Lead•ARUP-Bridges•COWI-Tunnel•SHTDI-Islands•FHCL-Electrical & MechanicalThis paper describes the design of the bridges on the link. The client for the link on the mainland side comprises the governments of the Guangdong Province PRC, Hong Kong SAR and Macao SAR. The client on the Hong Kong side is the Highways Department of the Hong Kong SAR

    The Influence of Ethnicity on the Development of Type 2 Diabetes Mellitus in Women with Gestational Diabetes: A Prospective Study and Review of the Literature

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    As the worldwide prevalence of type 2 diabetes continues to rise at an alarming rate, the search for susceptible populations likely to benefit from preventative measures becomes more important. One such population is women with a previous history of gestational diabetes mellitus (GDM). In this prospective study of 101 women who had GDM in Australia, ethnicity was a major risk factor for the development of diabetes following a diagnosis of GDM. With a mean followup of 5.5 years after GDM, South Asian women had a significantly higher risk of developing abnormal glucose tolerance (AGT) (69%) than women of all other ethnicities (P < 0.05). The prevalence of diabetes and impaired glucose tolerance was also very high amongst other groups: South East and East Asian (11/27, 41%), Middle-Eastern (8/18, 44%), South European backgrounds (5/12, 42%), and Australian-born women 39% (11/28). A review of the literature supports the role of ethnicity in the development of diabetes amongst these women. These findings have implications for South Asian countries and countries such as Australia where there is a population from diverse ethnic backgrounds and where the implementation of targeted measures to stem the growing tide of diabetes is needed

    Dendritic Integration of Sensory Evidence in Perceptual Decision-Making

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    Perceptual decisions require the accumulation of sensory information to a response criterion. Most accounts of how the brain performs this process of temporal integration have focused on evolving patterns of spiking activity. We report that subthreshold changes in membrane voltage can represent accumulating evidence before a choice. αβ core Kenyon cells (αβc KCs) in the mushroom bodies of fruit flies integrate odor-evoked synaptic inputs to action potential threshold at timescales matching the speed of olfactory discrimination. The forkhead box P transcription factor (FoxP) sets neuronal integration and behavioral decision times by controlling the abundance of the voltage-gated potassium channel Shal (KV4) in αβc KC dendrites. αβc KCs thus tailor, through a particular constellation of biophysical properties, the generic process of synaptic integration to the demands of sequential sampling

    Ga0.35In0.65 N0.02As0.08/GaAs bidirectional light-emitting and light-absorbing heterojunction operating at 1.3 μm

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    The Top-Hat hot electron light emission and lasing in semiconductor heterostructure (HELLISH)-vertical-cavity semiconductor optical amplifier (THH-VCSOA) is a bidirectional light-emitting and light-absorbing heterojunction device. The device contains 11 Ga0.35In0.65 N0.02As0.08/GaAs MQWs in its intrinsic active region which is enclosed between six pairs of AlAs/GaAs top distributed Bragg reflectors (DBRs) and 20.5 pairs of AlAs/GaAs bottom DBR mirrors. The THH-VCSOA is fabricated using a four-contact configuration. The wavelength conversion with amplification is achieved by the appropriate biasing of the absorption and emission regions within the device. Absorption and emission regions may be reversed by changing the polarity of the applied voltage. Emission wavelength is about 1,300 nm and a maximum gain at this wavelength is around 5 dB at T = 300 K

    A class of diagonal preconditioners for limited memory BFGS method.

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    A major weakness of the limited memory BFGS (LBFGS) method is that it may converge very slowly on ill-conditioned problems when the identity matrix is used for initialization. Very often, the LBFGS method can adopt a preconditioner on the identity matrix to speed up the convergence. For this purpose, we propose a class of diagonal preconditioners to boost the performance of the LBFGS method. In this context, we find that it is appropriate to use a diagonal preconditioner, in the form of a diagonal matrix plus a positive multiple of the identity matrix, so as to fit information of local Hessian as well as to induce positive definiteness for the diagonal preconditioner at a whole. The property of hereditary positive definiteness is maintained by a careful choice of the positive scalar on the scaled identity matrix while the local curvature information is carried implicitly on the other diagonal matrix through the variational techniques, commonly employed in the derivation of quasi-Newton updates. Several preconditioning formulae are then derived and tested on a large set of standard test problems to access the impact of different choices of such preconditioners on the minimization performance
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