The prevalence of hypotension and hypoxaemia in blunt traumatic brain injury in the prehospital setting of Johannesburg, South Africa: A retrospective chart review

BACKGROUND: Each year, ~89 000 (180/100 000) new cases of head injury are reported in South Africa (SA), with the majority of patients being in the economically active population. Hypotension and hypoxaemia significantly increase the morbidity and mortality in patients who have suffered a traumatic brain injury (TBI). Cerebral tissue is particularly vulnerable to these secondary insults in the period immediately following a TBI, emphasising the importance of prehospital care in TBI. OBJECTIVE: To establish the prevalence of prehospital hypotension and hypoxaemia in moderate to severe blunt TBI in greater Johannesburg, Gauteng, SA. METHODS: The records of adult patients who sustained a moderate to severe TBI between 1 January and 31 December 2011 were retrospectively reviewed for hypotension (systolic blood pressure <90 mmHg) and hypoxaemia (oxygen saturation <90%) during their prehospital phase of care. These results were subject to descriptive analysis. RESULTS: A total of 299 records were identified, 66 of which met the inclusion criteria. The prevalence of prehospital hypotension and hypoxaemia were 33.3% (n=22) and 37.9% (n=25), respectively, while 21.2% (n=14) of patients suffered double insults of hypotension and hypoxaemia. Hypotension and hypoxaemia were associated with haemorrhage (p=0.011) and chest injuries (p=0.001), respectively. CONCLUSION: The prevalence of hypotension in this study was similar to that observed in international studies, but the prevalence of hypoxaemia was much higher. There is a need for local guidelines to be developed to inform the quality of TBI care in the context of the developing world

Power law in a gauge-invariant cut-off regularisation

We study one-loop quantum corrections of a compactified Abelian 5d gauge field theory. We use a cut-off regularisation procedure which respects the symmetries of the model, i.e. gauge invariance, exhibits the expected power-like divergences and therefore allows the derivation of power-law behavior of the effective 4d gauge coupling in a coherent manner.Comment: 5 pages, 1 figure, 5 graphs, few references added, to appear in Phys.Rev. Rapid Communication

Scour development around a jacket structure in combined waves and current conditions compared to monopile foundations

This paper presents the results of an experimental study on the scour development of a hydraulic-transparent offshore foundation exposed to combined waves and current. Irregular waves propagating perpendicular to a current were simulated in a wave-current basin. The physical model tests were conducted in a length scale of 1:30 while measurements of the scour development over time were achieved by echo sounding devices placed at several locations at the upstream and downstream side of the jacket structure. Insights were gained on the scour development and time scale of the scouring process around a complex jacket structure for different wave-current conditions. The results were presented with respect to the Keulegan-Carpenter KC number and the relative wave-current velocity. Wave conditions were adjusted so that KC numbers between 6.7 and 23.4 could be tested in a systematic wave-current test program with tests reaching from wave dominated conditions up to current dominated conditions. Measured scour depths were critically assessed by an extrapolation to expected equilibrium scour depths. With respect to the current flow direction, the experiments showed generally larger scour depths at the upstream side and lower scour depths on the downstream side for each pile of the jacket structure. The development of global scour around the structure intensified with increasing relative wave-current velocity. As a result, a practical formulation is proposed for the reliable prediction of local scour depths around a jacket foundation in combined wave-current conditions. Finally, dimensionless time scales and observed as well as predicted scour depths are compared to values for the scour development around monopiles

High-Definition Optical Coherence Tomography for the in vivo Detection of Demodex Mites

Background: Demodex mites are involved in different skin diseases and are commonly detected by skin scrape tests or superficial biopsies. A new high-definition optical coherence tomography (HD-OCT) with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode might offer the possibility of noninvasive and fast in vivo examination of demodex mites. Methods: Twenty patients with demodex-related skin diseases and 20 age- and gender-matched healthy controls were examined by HD-OCT. Mites per follicle and follicles per field of view were counted and compared to skin scrape tests. Results: HD-OCT images depicted mites in the en-face mode as bright round dots in groups of 3-5 mites per hair follicle. In the patients with demodex-related disease, a mean number of 3.4 mites per follicle were detected with a mean number of 2.9 infested follicles per area of view compared to a mean of 0.6 mites in 0.4 infested follicles in the controls. The skin scrape tests were negative in 21% of the patients. Conclusion: The innovative HD-OCT enables fast and noninvasive in vivo recognition of demodex mites and might become a useful tool in the diagnosis and treatment monitoring of demodex-related skin diseases. Copyright (C) 2012 S. Karger AG, Base

The prevalence of hypotension and hypoxaemia in blunt traumatic brain injury in the prehospital setting of Johannesburg, South Africa: A retrospective chart review

Background. Each year, ~89 000 (180/100 000) new cases of head injury are reported in South Africa (SA), with the majority of patients being in the economically active population. Hypotension and hypoxaemia significantly increase the morbidity and mortality in patients who have suffered a traumatic brain injury (TBI). Cerebral tissue is particularly vulnerable to these secondary insults in the period immediately following a TBI, emphasising the importance of prehospital care in TBI.Objective. To establish the prevalence of prehospital hypotension and hypoxaemia in moderate to severe blunt TBI in greater Johannesburg, Gauteng, SA.Methods. The records of adult patients who sustained a moderate to severe TBI between 1 January and 31 December 2011 were retrospectively reviewed for hypotension (systolic blood pressure &lt;90 mmHg) and hypoxaemia (oxygen saturation &lt;90%) during their prehospital phase of care. These results were subject to descriptive analysis.Results. A total of 299 records were identified, 66 of which met the inclusion criteria. The prevalence of prehospital hypotension and hypoxaemia were 33.3% (n=22) and 37.9% (n=25), respectively, while 21.2% (n=14) of patients suffered double insults of hypotension and hypoxaemia. Hypotension and hypoxaemia were associated with haemorrhage (p=0.011) and chest injuries (p=0.001), respectively.Conclusion. The prevalence of hypotension in this study was similar to that observed in international studies, but the prevalence of hypoxaemia was much higher. There is a need for local guidelines to be developed to inform the quality of TBI care in the context of the developing world.

Brief review on the limit state function of dynamic scour protections

Offshore foundations, namely for offshore wind, wave and tidal applications, often require the use of scour protections. Rip-rap scour protections are an important element of the foundation to ensure that the natural frequency stays within the design limits. Scour protection design still presents a remarkable empirical nature, which typically leads to uncertainty on their behaviour under extreme met-ocean conditions. Therefore, reliability assessment of scour protections has been seen as a possibility to account for design uncertainty and to optimise the scour protections. However, the definition of a suitable limit state function is still a matter of research focus, namely, regarding the proper definition of the acceptable damage level for dynamic scour protections. This research provides a brief review on the recent studies related to both the limit state function and the calculation of damage numbers through bathymetric data. A discussion is raised on how the methodologies for calculating the damage number may influence the limit state function and a theoretical example is given to assess the effects on the probability of failure. Results have shown that the acceptable damage number requires a clearer definition, which should be based on the number of layers of rock material and the area of filter exposure. In addition, this research highlights the need for alternative ways to assess damage

High pressure study of BaFe2As2 - role of hydrostaticity and uniaxial stress

We investigate the evolution of the electrical resistivity of BaFe2As2 single crystals with pressure. The samples used were from the same batch grown from self flux and showed properties that were highly reproducible. Samples were pressurised using three different pressure media: pentane-isopentane (in a piston cylinder cell), Daphne oil (in an alumina anvil cell) and steatite (in a Bridgman cell). Each pressure medium has its own intrinsic level of hydrostaticity, which dramatically affects the phase diagram. An increasing uniaxial pressure component in this system quickly reduces spin density wave order and favours the appearance of superconductivity, similar to what is seen in SrFe2As2.Comment: 11 page