Study of sickle cell anaemia with clinical and hematological correlation

Background: Sickle cell anaemia is a hemoglobinopathy with the production of abnormal hemoglobin, HbS which when exposed to hypoxemia produces sickling of RBC. Severity of the disease depends on the percentage of HbS. Rise in the levels of Hb F is associated with less intense clinical course. Drugs targeted at increasing levels of HbF have prognostic significance. The aim of the study is to analyse the age, sex distribution, clinical, hematological and electrophoretic appearances and to compare with other studies.Methods: 300 sickle cell positive patients, both male and females who attended OPD were studied with all the clinical findings  and hematological parameters. 52 cases were subjected to electrophoresis.Results: Males were 154 and females were 146. Degree of anaemia was severe in females when compared to males. Of 52 cases subjected for electrophoresis 36 were homozygous, 15 were heterozygous and 1 case Sickle thalassemia. 7 cases showed HbF above 5%.Conclusions: Most of the patients were under 40 yrs suggesting decreased survival after that age.  An increased level of HbF was associated with better prognosis suggesting the need to target at drugs which increase HbF

Development, Validation, and Potential Enhancements to the Second-Generation Operational Aerosol Product at the National Environmental Satellite, Data, and Information Service of the National Oceanic and Atmospheric Administration

A revised (phase 2) single-channel algorithm for aerosol optical thickness, tau(sup A)(sub SAT), retrieval over oceans from radiances in channel 1 (0.63 microns) of the Advanced Very High Resolution Radiometer (AVHRR) has been implemented at the National Oceanic and Atmospheric Administration's National Environmental Satellite Data and Information Service for the NOAA 14 satellite launched December 30, 1994. It is based on careful validation of its operational predecessor (phase 1 algorithm), implemented for NOAA 14 in 1989. Both algorithms scale the upward satellite radiances in cloud-free conditions to aerosol optical thickness using an updated radiative transfer model of the ocean and atmosphere. Application of the phase 2 algorithm to three matchup Sun-photometer and satellite data sets, one with NOAA 9 in 1988 and two with NOAA 11 in 1989 and 1991, respectively, show systematic error is less than 10%, with a random error of sigma(sub tau) approx. equal 0.04. First results of tau(sup A)(sub SAT) retrievals from NOAA 14 using the phase 2 algorithm, and from checking its internal consistency, are presented. The potential two-channel (phase 3) algorithm for the retrieval of an aerosol size parameter, such as the Junge size distribution exponent, by adding either channel 2 (0.83 microns) from the current AVHRR instrument, or a 1.6-microns channel to be available on the Tropical Rainfall Measurement Mission and the NOAA-KLM satellites by 1997 is under investigation. The possibility of using this additional information in the retrieval of a more accurate estimate of aerosol optical thickness is being explored

Sodium channel myotonia may be associated with high-risk brief resolved unexplained events [version 1; peer review: awaiting peer review]

Brief resolved unexplained events (BRUEs) have numerous and varied causes posing a challenge to investigation and management. A subset of infants with the neuromuscular disorder sodium channel myotonia, due to mutations in the SCN4A gene, experience apnoeic events due to laryngospasm (myotonia) of the upper airway muscles that may present as a BRUE. We sought to ascertain the frequency, severity and outcome of infants carrying the G1306E SCN4A mutation commonly associated with this presentation. We report 12 new cases of individuals with the G1306E mutation from three unrelated families and perform a literature review of all published cases. Infants with the G1306E mutation almost universally experience laryngospasm and apnoeic events. The severity varies significantly, spans both low and high-risk BRUE categories or can be more severe than criteria for a BRUE would allow. At least a third of cases require intensive care unit (ICU) care. Seizure disorder is a common erroneous diagnosis. Apnoeas are effectively reduced or abolished by appropriate treatment with anti-myotonic agents. Probands with the G1306E mutation who are family planning need to be counselled for the likelihood of post-natal complications. There is readily available and extremely effective treatment for the episodic laryngospasm and apnoea caused by this mutation. Proactively seeking clinical evidence of myotonia or muscle hypertrophy with consideration of CK and EMG in high risk BRUEs or more complex apnoeic events may reduce avoidable and prolonged ICU admissions, patient morbidity and potentially mortality. Keyword

Direct observation of LO phonon-plasmon coupled modes in the infrared transmission spectra of n-GaAs and n-InxGa1-xAs epilayers

The infrared transmission spectrum of Si-doped molecular beam epitaxy (MBE)-grown GaAs epilayers, 2-2.5-mum thick, measured in the oblique (Berreman) geometry, revealed distinct minima in p polarization. Given epilayer thickness \u3c reststrahlen wavelength, the minima are identified as the zone-center transverse optic phonon (omega(TO)) and the high-frequency LO phonon-plasmon coupled mode (omega(+)). Analysis of the experimental data yielded free-carrier concentrations ranging from 2.5x10(17) to 1.4x10(18) cm(-3). The same technique with MBE-grown Si-doped In0.53Ga0.47As epilayers (0.5-1 mum thick) yielded omega(+) modes corresponding to free-carrier concentrations of 8.2x10(16)-2.7x10(19) cm(-3). The observations of the transmission minima in the Berreman geometry and their interpretation demonstrate a direct and simple method for deducing free-carrier concentrations over a wide range

Isotopic-mass dependence of the A, B, and C excitonic band gaps in ZnO at low temperatures

Low temperature wavelength-modulated reflectivity measurements of isotopically engineered ZnO samples have yielded the dependence of their A, B, and C excitonic band gaps on the isotopic masses of Zn and O. The observed dependence is analyzed in terms of the band gap renormalization by zero-point vibrations via electron-phonon interaction and the volume dependence on isotopic mass. A simplified, two-oscillator model, employed in the analysis, yields zero-point renormalizations of the band gaps, -154 +/- 14 meV (A), -145 +/- 12 meV (B), and -169 +/- 14 meV (C), for ZnO with natural isotopic composition

Photoluminescence of short-period GaAs/AlAs superlattices: A hydrostatic pressure and temperature study

URL:http://link.aps.org/doi/10.1103/PhysRevB.58.7222 DOI:10.1103/PhysRevB.58.7222The temperature and pressure dependence of type-I and -II transitions from photoluminescence (PL) spectra in a series of (GaAs)m/(AlAs)m superlattices show that the temperature dependence of energy bands can be described very well with a Bose-Einstein-type equation. From these measurements the parameters that describe the temperature dependence of excitonic transition energies and the corresponding broadening of the PL line are deduced. The pressure dependence of the PL linewidths of the type-I exciton as a function of pressure and temperature yield the intervalley deformation potential. Beyond the type-I-type-II crossover, the PL linewidth increases as a function of both pressure and temperature. The electron-phonon deformation potential for Γ-X scattering is found to be temperature dependent.We thank S. Satpathy and S. Zollner for valuable discussions. One of us ~H.R.C.! acknowledges support by the NSF under Grant No. DMR-9633107. M.C. thanks the U.S. Army for support through Grant No. DAAL03-92-0381. The work at Purdue University was supported by the National Science Foundation: Materials Research Science and Engineering Center Grant Nos. DMR 94-00415 and DMR 93-03186