Post-growth annealing induced change of conductivity in As-doped ZnO grown by radio frequency magnetron sputtering

Arsenic-doped ZnO films were fabricated by radio frequency magnetron sputtering method at a relatively low substrate temperature of 200 C. Post-growth annealing in air was carried out up to a temperature of 1000 C. The samples were characterized by Hall measurement, positron annihilation spectroscopy (PAS), secondary ion mass spectroscopy (SIMS), and cathodoluminescence (CL). The as-grown sample was of n-type and it converted to p-type material after the 400 C annealing. The resulting hole concentration was found to increase with annealing temperature and reached a maximum of 6 10 17cm -3 at the annealing temperature of 600 C. The origin of the p-type conductivity was consistent with the As Zn(V Zn) 2 shallow acceptor model. Further increasing the annealing temperature would decrease the hole concentration of the samples finally converted the sample back to n-type. With evidence, it was suggested that the removal of the p-type conductivity was due to the dissociation of the As Zn(V Zn) 2 acceptor and the creation of the deep level defect giving rise to the green luminescence. © 2011 American Institute of Physics.published_or_final_versio

Luminescent zinc(ii) and copper( i) complexes for high-performance solution-processed monochromic and white organic light-emitting devices

published_or_final_versio

Effects of serum proteins on corrosion behavior of ISO 5832–9 alloy modified by titania coatings

Stainless steel ISO 5832–9 type is often used to perform implants which operate in protein-containing physiological environments. The interaction between proteins and surface of the implant may affect its corrosive properties. The aim of this work was to study the effect of selected serum proteins (albumin and γ-globulins) on the corrosion of ISO 5832–9 alloy (trade name M30NW) which surface was modified by titania coatings. These coatings were obtained by sol– gel method and heated at temperatures of 400 and 800 °C. To evaluate the effect of the proteins, the corrosion tests were performed with and without the addition of proteins with concentration of 1 g L−1 to the physiological saline solution (0.9 % NaCl, pH 7.4) at 37 °C. The tests were carried out within 7 days. The following electrochemical methods were used: open circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy. In addition, surface analysis by optical microscopy and X-ray photoelectron spectroscopy (XPS) method was done at the end of weekly corrosion tests. The results of corrosion tests showed that M30NW alloy both uncoated and modified with titania coatings exhibits a very good corrosion resistance during weekly exposition to corrosion medium. The best corrosion resistance in 0.9 % NaCl solution is shown by alloy samples modified by titania coating annealed at 400 °C. The serumproteins have no significant effect onto corrosion of investigated biomedical steel. The XPS results confirmed the presence of proteins on the alloy surface after 7 days of immersion in proteincontaining solutions.The investigations were supported by the National Science Centre project No. N N507 501339. The authors gratefully acknowledge Dr. Janusz Sobczak and Dr. hab. Wojciech Lisowski from Institute of Physical Chemistry of PAS for XPS surface analyses

Maternal and perinatal outcome of severe pre-eclampsia in Enugu, Nigeria after introduction of Magnesium sulfate

Background: Magnesium sulfate (MgSO4) is the most effective seizure prophylaxis in the management of severe preeclampsia, and its use is progressively spreading in our environment. It was introduced at the pioneer teaching hospital of southeastern Nigeria in 2007. A study on the outcome of its use is therefore necessary.Objectives: The objective was to determine the effect of introducing MgSO4 on the maternal and perinatal outcomes of severe pre-eclampsia in Enugu, South eastern Nigeria.Materials and Methods: A retrospective study of all cases of severe pre-eclampsia managed at the University of Nigeria Teaching Hospital Enugu (UNTH), Nigeria, from 1 January 2005 to 31 December 2008 - 2 years before, and 2 years after the introduction of MgSO4 – was performed.Result: The prevalence of severe preeclampsia within the study period was 3.3%. The mean age of study participants was 24.5 ± 2.9 years. Thirty women received MgSO4 while 47 women received diazepam. Eclampsia occurred only in a member of the diazepam group but there were no maternal deaths. Babies from the diazepam group were more likely to have low 1 minute Apgar scores but the association was not significant [OR = 3.08 (95% CI 0.78, 13.33)]. Longer hospital stay was significantly lower among women who received MgSO4 [OR = 0.32 (95% CI 0.11, 0.93)]. Perinatal mortality did not differ between the groups.Conclusion: MgSO4 is effective in the management of severe pre-eclamptics at the UNTH, Enugu. Therefore, its accessibility and wider use should be promoted

The socioeconomic burden of SLE.

Systemic lupus erythematosus (SLE) is a chronic, relapsing-remitting, multisystemic autoimmune inflammatory disorder that predominantly affects women of childbearing age. Much has been written about the clinical course and long-term damage associated with SLE, as well as the reduced life expectancy of patients with this condition. In addition, studies have emphasized the socioeconomic and psychosocial impact of SLE, although the monetary cost of caring for patients with the disorder has only been evaluated in a modest number of studies and a restricted number of countries. SLE has a negative impact on quality of life and is associated with high health-care costs and significant productivity loss. Factors associated with increased cost of SLE include long disease duration, high disease activity and damage, poor physical and mental health, and high education and employment levels. Similarly, high disease activity and damage, poor physical health, certain disease manifestations, as well as poor family and social support are associated with poor health-related quality of life outcomes. SLE incurs a great burden on both the patient and society. Long-term prospective studies should be encouraged to monitor the costs and psychosocial impact of this condition, and to better understand the factors that are associated with poor outcomes.postprin

Congenital Toxoplasmosis: A Review of its Pathology, Immune Response and Current Treatment Options.

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common parasites of man and other warm-blooded animals. Humans are infected through contaminated food, water, and blood transfusion, organ transplantation or from mother to foetus through the placenta. Severe congenital infections occur as a result of primary T. gondii infection in early pregnancy. Transmission of T.gondii to the foetus can result in serious health problems, including mental retardation, seizures, blindness and death. Frequency of foetal infection is higher when maternal infection occurs later in pregnancy and sequelae are more severe when maternal infections occur early in the first trimester of pregnancy. The ability of the parasite to survive intracellularly largely depends on the blocking of different proapoptotic signaling cascades of the host cells. During pregnancy, however, alterations in the incidence of apoptosis are associated with abnormal placental morphology and function. Both cellular and humoral immune responses control T.gondii infection. Toxoplasma is asymptomatic, infected women can only be detected by serological testing. In many instances, congenital toxoplasmosis can be prevented by educating pregnant women and women of childbearing age about the route of transmission. The need for screening suspected cases of T. gondii will help reduce transmission to the foetus. Keywords: Toxoplasmosis, Congenital toxoplasmosis, Toxoplasmosis and immunosuppression. Toxoplasma gondii

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Centrifuge modelling of the effects of root geometry on transpiration-induced suction and stability of vegetated slopes

Shallow landslides (i.e., 1 - 2 m depth) on both man-made and natural slopes are of major concern worldwide that has led to huge amount of socio-economical losses. The use of vegetation has been considered as an environmentally friendly means of stabilising slopes. Existing studies have focused on the use of plant roots with different geometries to mechanically stabilise soil slopes, but there are little data available on the contribution of transpiration-induced suction to slope stability. This study was designed to quantify both the hydrological and mechanical effects of root geometry on the stability of shallow slopes. Centrifuge tests were conducted to measure soil suction in slope models supported by newly-developed artificial roots. These artificial roots exhibit three different representative geometries (i.e., tap, heart and plate) and could simulate the effects of transpiration. The measured suction was then back-analysed through a series of finite element seepage-stability analyses to determine the factor of safety (FOS). It is revealed that after a rainfall event with a return period of 1000 years, the slope supported by heart-shaped roots retained the highest suction of 3 kPa within the root depth and thus this type of root provided the greatest stabilisation effects. The FOS of the slope supported by the heart-shaped roots, through both mechanical reinforcement and transpiration-induced suction, is 16% and 28% higher than that supported by the tap- and plate-shaped roots, respectively