Socio-epidemiological aspects of respiratory allergic diseases in Southern Africa

The prevalence of respiratory allergic diseases has been increasing in Southern Africa both in urban and in rural environments. Various factors may contribute toward this situation, namely, exposure to aeroallergens, such as grass pollens and house dust mites. However, other irritant environmental triggers, such as exposure to tobacco smoke and certain indoor and outdoor fumes, may also play a relevant part. Furthermore, certain parasitic and mycobacterial infections may act as allergic disease risk modifiers, although such an influence should be confirmed. Finally, certain cultural and socioeconomic factors may also influence accessibility to healthcare and adherence to treatment of these diseases

Thermal effects on the hydraulic conductivity of a granular geomaterial

Geotechnical challenges arising from thermal loading are associated with many engineering applications such as ground source energy systems (5℃-40℃) and nuclear waste disposal (in excess of 100℃). The effects of temperature on soils have been the subject of limited research, particularly in terms of the fundamental characterisation of the non-isothermal behaviour of granular geomaterials. This study describes challenges associated with determining the hydraulic conductivity (k_ℎ) of such materials at different temperatures using a bespoke temperature-controlled triaxial apparatus. A methodology is proposed for interpreting thermo-hydro-mechanical (THM) tests on isotropically consolidated specimens and is applied to data obtained for a uniform sand. It is shown that the intrinsic head losses of the system need to be minimised in order to obtain reliable measurements; this requires a detailed calibration procedure. The developed approach is used to determine the hydraulic conductivity at ambient temperature and at 40℃, showing that the increase in k_ℎ with temperature is mostly due to the reduction in the viscosity of water. A detailed analysis of the volumetric response of the sample during heating is also carried out

Neonatal meningitis associated with osteomyelitis and epidural empyema.

Neonatal meningitis is a serious disease with significant mortality and morbidity. Its signs and symptoms are subtle, non-specific, atypical or absent. Cephalohaematoma is frequent in newborns and complications are uncommon, including local infection after haematogenous spread in the setting of bacteraemia or meningitis with a possibility of osteomyelitis, epidural abscess and subdural empyema. We report the case of a late preterm newborn, with an unremarkable pregnancy, born by vacuum-assisted vaginal delivery that presented in the fifth day of life with irritability, fever and grunting. Cerebrospinal fluid and blood cultures were positive for Escherichia coli. The patient had neurological deterioration despite adequate antibiotic therapy and brain MRI showed a right parietal epidural empyema, subcutaneous abscess, osteomyelitis and supratentorial hydrocephalus. The culture of the cephalohaematoma's abscess material was positive for E coli. Antibiotic therapy was continued for 8 weeks. The child, now 2 years old, has spastic tetraparesis with global development delay

Catheter-associated urinary tract infection in medical patients of a Portuguese hospital: incidence and risk factors

info:eu-repo/semantics/publishedVersio

Physical and chemical processing of printed circuit boards waste

A recycling process for PCB’s is being studied, based on physical processing and hydrometallurgical treatment. PCB’s waste was shredded in a lab cutting mill, resulting a grinded material with 90% (weight) with particle size less than 2.1 mm and an average particle diameter of 1.2 mm. Chemical analysis of granulometric fractions showed that the base metals like Cu, Zn, Pb and Sn concentrated mainly in intermediate size fractions (0.4-1.7 mm) being fines very rich in epoxy resin composite. About 80-90% of the principal metals were recovered in that size range. The first step of chemical treatment was the acid leaching of metals. The use of nitric acid solutions at appropriate conditions allowed the efficient solubilization of base metals like Cu, Ni, Zn, Pb and Ag. More than 90% recovery of Cu, Zn and Ni were achieved at 90ºC using 1 M HNO3. Dissolution of silver required higher concentrations (only 70% yield using 2 M HNO3). Tin leaching was inefficient in nitric media, being always lower than 20%. The leaching conditions here reported were adequate to the base metals solubilization, allowing further processing of leachates for separation and recovery using hydrometallurgical operations. Precious metals recovery would be attained in a subsequent leaching step using highly concentrated acidic solutions

Leaching studies for metals recovery from printed circuit boards scrap

In this paper, the leaching behavior of the major metals present in printed circuit boards waste is evaluated, aiming at its recycling by hydrometallurgy. Several leachants were compared (sulfuric, hydrochloric and nitric acids, at 2 M H+ concentration), at temperatures of 25ºC and 90ºC and 4 hours of reaction time. Sulfuric acid leaching was not very promising concerning metals dissolution being only effective for iron. Hydrochloric acid allowed the leaching up to 60% of tin and about 50% of lead, as well as the iron. Nitric acid was the most efficient leachant due to its oxidizing properties. Recoveries of 90% or more for copper, iron, nickel and zinc were achieved at the higher temperature. Lead was also dissolved (up to 80%), as well as silver (more than 70%). These results show that the hydrometallurgical recovery of most of the metals present in PCB’s scrap is a technically feasible alternative that shall be considered and evaluated

CdTe detector based PIXE mapping of geological samples

A sample collected from a borehole drilled approximately 10 km ESE of Bragança, Trás-os-Montes, was analysed by standard and high energy PIXE at both CTN (previous ITN) PIXE setups. The sample is a fine-grained metapyroxenite grading to coarse-grained in the base with disseminated sulphides and fine veinlets of pyrrhotite and pyrite. Matrix composition was obtained at the standard PIXE setup using a 1.25 MeV H+ beam at three different spots. Medium and high Z elemental concentrations were then determined using the DT2fit and DT2simul codes (Reis et al., 2008, 2013 [1] and [2]), on the spectra obtained in the High Resolution and High Energy (HRHE)-PIXE setup (Chaves et al., 2013 [3]) by irradiation of the sample with a 3.8 MeV proton beam provided by the CTN 3 MV Tandetron accelerator. In this paper we present results, discuss detection limits of the method and the added value of the use of the CdTe detector in this context