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

Influence of the gate leakage current on the stability of organic single-crystal field-effect transistors

We investigate the effect of a small leakage current through the gate insulator on the stability of organic single-crystal field-effect transistors (FETs). We find that, irrespective of the specific organic molecule and dielectric used, leakage current flowing through the gate insulator results in an irreversible degradation of the single-crystal FET performance. This degradation occurs even when the leakage current is several orders of magnitude smaller than the source-drain current. The experimental data indicate that a stable operation requires the leakage current to be smaller than $10^{-9} \ \mathrm{A/cm}^2$. Our results also suggest that gate leakage currents may determine the lifetime of thin-film transistors used in applications.Comment: submitted to Appl. Phys. Let

Experimental Test of Momentum Cooling Model Predictions at COSY and Conclusions for WASA and HESR

The High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an anti-proton cooler ring in the momentum range from 1.5 to 15 GeV/c. An important and challenging feature of the new facility is the combination of highly dense phase space cooled beams with internal targets. A detailed numerical and analytical approach to the Fokker-Planck equation for longitudinal filter cooling including the beam - target interaction has been carried out to demonstrate the stochastic cooling capability. To gain confidence in the model predictions a series of experimental stochastic cooling studies with the internal target ANKE at COSY have been carried out. A remarkable agreement between model and experiment was achieved. On this basis longitudinal stochastic cooling simulations were performed to predict the possibilities and limits of cooling when the newly installed WASA Pellet-target is operated.Comment: 17 pages, 11 figures, Talk given at Symposium on Meson Physics at COSY-11 and WASA-at-COSY, Cracow, Poland, 17-22 Jun 200

Chemical Studies on the Stability of Soil Aggregates : Change in Permeability of Soil Aggregate Column Induced bu Percolating with Neutral and Alkaline Solution

既報の結果に基づいて推論した粒団生成に関与する成分が, 果して土粒子の耐水性連結にいかなる役割を演じているかを明らかにする研究の一環として, 静置状態で土壌粒団に中性ならびにアルカリ性の溶液を透過させて土壌から特定の成分の離脱を試み, その場合に起こる粒団の崩壊と土壌の持つ透液性の変移をしらべた。1. 主として水溶性と置換性の成分を土壌から溶脱する機能のある0.05N塩化ナトリウム溶液を土壌粒団に透過させると土壌粒団の崩壊ならびに透液性の低下は極めて少なかった。したがって, 置換性塩基類は粒団の安定性に対し大きな役割を果していないことが明らかになった。2. アルカリ性の腐植抽出剤である0.5%水酸化ナトリウム溶液を土壌粒団に透過させると, 粒団の崩壊が著しく, それに応じて土壌の持つ透液性も低下した。しかし, 土壌からの腐植の離脱量と透液性の低下との間に認められた相関は高くないので粒団の安定性は腐植の単独作用によって律せられるものでないことがわかった。この際同時にアルミニウムがかなり多量に離脱され, これが粒団の安定性に関与することが類推された。3. 中性の腐植抽出剤である0.1Mピロ燐酸ナトリウム溶液を土壌粒団に透過させると, 土壌の種類によってその程度はかなり異なるが概して粒団崩壊と透液比の低下は大きかった。ところが, 土壌から離脱した腐植量と透液比の低下との間には相関が見出せなかった。ピロ燐酸ナトリウム溶液は土壌から腐植と同時に鉄, アルミニウム, カルシウムなどの無機成分を溶脱し, これらの正電荷を抑えて土粒の分散を促がす機能が高いから, この場合の粒団の崩壊はとくに同時に離脱する鉄やアルミニウムによるところが大きいと考えられる。 / With the object to determine the kinds of binding materials in soil aggregates and the part played by each of them, experiments were made on the effect of percolation with neutral or alkaline solution on the aggregate stability. The results obtained are as follows : 1) Aggregates were not greatly affected by the treatment with 0.05N sodium chloride solution. Hence, the part played by exchangeable bases appeared not large in the stabilization of aggregates. 2) When 0.5% sodium hydroxide solution was passed through the column to remove humus from aggregates, the permeability was remarkably lowered. But since the amount of humus removed was not so closely related to the degree of lowering in permeability, the aggregate stability did not seem attributable to the function of humus alone. It was suggested that aluminum removed from aggregates in a large amount in addition to humus participates in their stability. 3) When treated with 0.1M sodium pyrophosphate solution, neutral reagent for humus extraction, the aggregates were markedly broken down and their permeability was greatly lowered, though not without some differences in the extent of effect among the kinds of soil. On the other hand, no distinct correlation was found between the amount of humus removed and the degree of lowering in permeability ratio (the ratio of the permeability at any given time after treatment, Pt, to the initial permeability, Pi). In this case, inorganic components such as aluminum and iron, which were removed by sodium pyrophosphate solution in addition to humus, were considered to be intimately concerned with the result. 4) From these results, it may be indicated that the part played by the combined action of humus and aluminum or iron is important for the stability of soil aggregates

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.

Discriminating between simple and perforated appendicitis

Background: Several studies have been performed in order to diagnose an acute appendicitis using history taking and laboratory investigations. The aim of this study was to create a model for the identification of a perforated appendicitis. Methods: All consecutive patients who have undergone an appendectomy in the Reinier de Graaf hospital between January 1, 2007 and July 31, 2009, were included in a retrospective cohort study. Baseline patient characteristics, history and laboratory data were collected. Variables discriminating perforated from non-perforated appendicitis were identified using univariate and multivariable analyses. Results: A total of 498 patients were included in the study. In the univariate analysis leukocyte count, C-Reactive Protein levels, Erythrocyte Sedimentation Rate levels, days of symptoms and temperature were identified as predictors of perforated appendicitis. The predicted probability (P) of a perforated appendicitis can be calculated from the following model: (P) = 1/(1 + e(-(-2.788 + 0.012 CRP+0.207days with complaints))). Conclusions: Perforation of appendicitis can be predicted from the CRP level and the duration of abdominal pain. These findings might influence th

Preinfection in vitro chemotaxis, phagocytosis, oxidative burst, and expression of CD11/CD18 receptors and their predictive capacity on the outcome of mastitis induced in dairy cows with Escherichia coli.

Four to 6 wk after parturition, 12 cows in second, fourth, or fifth lactation were experimentally infected in one gland with Escherichia coli. The capacity of chemotaxis, phagocytosis, oxidative burst, and expression of CD11/CD18 receptors to predict the severity of IMI was measured. Bacterial counts in the infected quarter, expressed as area under the curve, and residual milk production in the uninfected quarters were compared to determine severity of the infection. Although these two outcome parameters were highly negatively correlated, regression models with preinfection tests for leukocyte function fitted best with bacterial counts as an outcome parameter. Of the preinfection tests for leukocyte function, chemotaxis best predicted the outcome of the IMI that had been experimentally induced by E. coli. The number of circulating peripheral leukocytes just prior to inoculation was used to predict 52 and 45% of the severity of IMI for bacterial counts and residual milk production, respectively. As a categorical variable, parity predicted 75 and 56% of the severity of IMI expressed as bacterial counts and residual milk production, respectively. Because of the strong effect of parity on the outcome of the experimentally induced mastitis, analysis was performed to discriminate between second parity cows and older cows. Significant differences were found for the number of circulating peripheral leukocytes and for the expression of CD11b/CDl8 and CD11c/CD18 receptors between younger and older cows

Two-dimensional core–shell donor–acceptor assemblies at metal–organic interfaces promoted by surface-mediated charge transfer

Organic charge transfer (CT) complexes obtained by combining molecular electron donors and acceptors have attracted much interest due to their potential applications in organic opto-electronic devices. In order to work, these systems must have an electronic matching – the highest occupied molecular orbital (HOMO) of the donor must couple with the lowest unoccupied molecular orbital (LUMO) of the acceptor – and a structural matching, so as to allow direct intermolecular CT. Here it is shown that, when molecules are adsorbed on a metal surface, novel molecular organizations driven by surface-mediated CT can appear that have no counterpart in condensed phase non-covalent assemblies of donor and acceptor molecules. By means of scanning tunneling microscopy and spectroscopy it is demonstrated that the electronic and self-assembly properties of an electron acceptor molecule can change dramatically in the presence of an additional molecular species with marked electron donor character, leading to the formation of unprecedented core–shell assemblies. DFT and classical force-field simulations reveal that this is a consequence of charge transfer from the donor to the acceptor molecules mediated by the metallic substrate

A new instrument to measure high value, cost-conscious care attitudes among healthcare stakeholders: Development of the MHAQ

Background: Residents have to learn to provide high value, cost-conscious care (HVCCC) to counter the trend of excessive healthcare costs. Their learning is impacted by individuals from different stakeholder groups within the workplace environment. These individuals' attitudes toward HVCCC may influence how and what residents learn. This study was carried out to develop an instrument to reliably measure HVCCC attitudes among residents, staff physicians, administrators, and patients. The instrument can be used to assess the residency-training environment. Method: The Maastricht HVCCC Attitude Questionnaire (MHAQ) was developed in four phases. First, we conducted exploratory factor analyses using original data from a previously published survey. Next, we added nine items to strengthen subscales and tested the new questionnaire among the four stakeholder groups. We used exploratory factor analysis and Cronbach's alphas to define subscales, after which the final version of the MHAQ was constructed. Finally, we used generalizability theory to determine the number of respondents (residents or staff physicians) needed to reliably measure a specialty attitude score. Results: Initial factor analysis identified three subscales. Thereafter, 301 residents, 297 staff physicians, 53 administrators and 792 patients completed the new questionnaire between June 2017 and July 2018. The best fitting subscale composition was a three-factor model. Subscales were defined as high-value care, cost incorporation, and perceived drawbacks. Cronbach's alphas were between 0.61 and 0.82 for all stakeholders on all subscales. Sufficient reliability for assessing national specialty attitude (G-coefficient > 0.6) could be achieved from 14 respondents. Conclusions: The MHAQ reliably measures individual attitudes toward HVCCC in different stakeholders in health care contexts. It addresses key dimensions of HVCCC, providing content validity evidence. The MHAQ can be used to identify frontrunners of HVCCC, pinpoint aspects of residency training that need improvement, and benchmark and compare across specialties, hospitals and regions

Canine NAPEPLD-associated models of human myelin disorders

Canine leukoencephalomyelopathy (LEMP) is a juvenile-onset neurodegenerative disorder of the CNS white matter currently described in Rottweiler and Leonberger dogs. Genome-wide association study (GWAS) allowed us to map LEMP in a Leonberger cohort to dog chromosome 18. Subsequent whole genome re-sequencing of a Leonberger case enabled the identification of a single private homozygous non-synonymous missense variant located in the highly conserved metallo-beta-lactamase domain of the N-acyl phosphatidylethanolamine phospholipase D (NAPEPLD) gene, encoding an enzyme of the endocannabinoid system. We then sequenced this gene in LEMP-affected Rottweilers and identified a different frameshift variant, which is predicted to replace the C-terminal metallo-beta-lactamase domain of the wild type protein. Haplotype analysis of SNP array genotypes revealed that the frameshift variant was present in diverse haplotypes in Rottweilers, and also in Great Danes, indicating an old origin of this second NAPEPLD variant. The identification of different NAPEPLD variants in dog breeds affected by leukoencephalopathies with heterogeneous pathological features, implicates the NAPEPLD enzyme as important in myelin homeostasis, and suggests a novel candidate gene for myelination disorders in people