Methodology for Designing and Evaluating Chemical Systems for Improved Oil Recovery

The purpose of this research was to demonstrate the methodology for development of high performance chemical systems for improved oil recovery (IOR). Previous studies have shown that high performing surfactant formulations can be quickly identified and optimized by assessing the microemulsion phase behavior and aqueous phase homogeneity. Similarly, in this research, extensive phase behavior assessments were performed for many combinations of chemical slug components that included various surfactants, co-surfactants, co-solvents, alkali and polymers. Methodical planning, preparation, execution, observations and recording of phase behavior experiments and results enabled selection of the best performing chemical components and their concentrations were optimized. A total of five formulations showed good microemulsion phase behavior but only three passed the aqueous stability requirement. These three formulations were then evaluated in core floods. Out of the three formulations, one consistently gave high residual oil recovery ranging between 86%-91% at reservoir temperature with both soft brine (NaCl only) and synthetic formation brine. Synthetic formation brine for Trembley contained a high concentration of divalent cations in addition to monovalent yet it had a minimal effect on oil recovery, proving that the formulation was robust at even high salinity contrast with formation brine. The formulation was therefore recommended for further studies on limestone cores. Pressures across the sandstone cores and its subsections, and effluent's microemulsion and aqueous phase properties were utilized to explain the performance of formulations and oil displacement process in the sandstone cores. Corefloods showed that slug size, surfactant concentration, salinity and viscosity of chemical systems were important chemical flood design parameters that also impacted the oil recovery

COVID-19 presenting with spontaneous pneumothorax

The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease mainly affects respiratory system. Its common clinical findings include fever, cough and shortness of breath. Characteristic radiological features of the disease include peripherally distributed, bilateral ground-glass opacities, predominantly involving the lower lung zones. In this report, we present a case of COVID-19 disease presenting with spontaneous pneumothorax. A 26-year male patient was admitted to the Emergency Department with fever, dry cough, shortness of breath and right-sided chest pain. Radiographic imaging of the patient revealed pneumothorax on the right and peripherally distributed non-homogenous opacification. The patient underwent right lateral tube thoracostomy. COVID-19 was diagnosed on testing of nasopharyngeal swab. In conclusion, spontaneous pneumothorax is one of the rare presentations of COVID-19 pneumonia and should be kept in mind in patients presenting with shortness of breath and chest pain

Distribution of Helicobacter pylori virulence markers in patients with gastroduodenal diseases in Pakistan

<p>Abstract</p> <p>Background</p> <p><it>Helicobacter pylori </it>(<it>H. pylori</it>) infection is known to be associated with a spectrum of gastroduodenal diseases. We studied the association of <it>H. pylori </it>virulence markers cytotoxin-associated gene (<it>cagA</it>) and vacuolating associated cytotoxin gene (<it>vacA</it>) alleles in patients with non ulcer dyspepsia (NUD), gastric ulcer (GU), gastric carcinoma (GC) and duodenal ulcer (DU).</p> <p>Methods</p> <p><it>H. pylori </it>infection established by both rapid urease test and histology were studied. The <it>cagA </it>and <it>vacA </it>allelic status was determined by polymerase chain reaction (PCR). Sequencing of <it>vacA i1 </it>and <it>i2 </it>PCR product was carried out.</p> <p>Results</p> <p>Two hundred and twenty-four patients were included, 141 (63%) were males with a mean age of 45 ± 16, range 16-83 years. The virulence marker <it>cagA </it>was associated with GU in 20(63%) (p = 0.04), DU in 23(72%) (p = 0.003) and GC in 29(73%) (p = 0.001) compared to NUD in 51(42%). <it>VacA s1am1 </it>was associated with GU in 23(72%) (p = 0.001), DU in 17(53%) (p < 0.001) and GC in 23(58%) (p = 0.003) compared to NUD in 38(32%) while <it>vacA s1bm1 </it>was also associated with GU in 9(28%) (p = 0.001), DU in 12(37%) (p < 0.001) and GC 11(28%) (p < 0.001) compared to NUD in 13(11%), respectively. The diagnoses of GU in 21(66%), DU in 16(50%), GC in 20(50%) and NUD in 50(42%) were associated with moderately active chronic inflammation. <it>CagA </it>in 55(45%) (p = 0.037), <it>vacA s1am1 </it>in 51(51%) (P < 0.001), <it>s1bm1 </it>in 25(56%) (p = 0.002), <it>s1am2 </it>32(30%) (p < 0.001) and <it>s1bm2 </it>29(69%) (p = 0.004) were also associated with moderately active chronic inflammation.</p> <p>Conclusion</p> <p><it>CagA </it>was negative in majority of NUD patients with <it>H. pylori </it>infection. However, <it>cagA </it>was associated with peptic ulcer and GC. <it>VacA </it>allele's <it>s1am1 </it>and <it>s1bm1 </it>were associated with <it>H. pylori </it>associated diseases and inflammation.</p

Professionalism in medical students at a private medical college in Karachi, Pakistan

Objective: To determine levels of professionalism in undergraduate medical students at a private medical college and assess how changes emerge during their training. Methods: The study was conducted at Aga Khan University, a tertiary care teaching hospital, during November and December 2011. Freshmen, Year 3 and Year 5 students were requested to fill out a questionnaire. It was designed to assess the participants\\u27 levels of professionalism and how they perceived the professional environment around them by incorporating previously described scales. The questionnaire was re-validated on a random sample of practising clinicians at the same hospital. SPSS 17 was used for statistical analysis. Results: The study sample comprised 204 participants. The mean score for level of individual professionalism was 7.72±3.43. Only 13 (6.4%) students had a score one standard deviation above the faculty mean. About 24 (11.8%) were one standard deviation and 35 (17.2%) were 2 standard deviations below the faculty mean. The remaining 130 (63.7%) were \u3e2 standard deviations below the faculty mean. Considering the level of education, the mean score for level of professionalism was 8.00±3.39 for freshmen, 6.85±3.41 for year 3 students, and 8.40±3.34 for year 5 students. Conclusion: The currently employed teaching practices inculcating the values of professionalism in medical students are serving as a buffer to maintain the pre-training levels of professionalism from declining

The Karachi intracranial stenosis study (KISS) Protocol: an urban multicenter case-control investigation reporting the clinical, radiologic and biochemical associations of intracranial stenosis in Pakistan.

Background: Intracranial stenosis is the most common cause of stroke among Asians. It has a poor prognosis with a high rate of recurrence. No effective medical or surgical treatment modality has been developed for the treatment of stroke due to intracranial stenosis. We aim to identify risk factors and biomarkers for intracranial stenosis and to develop techniques such as use of transcranial doppler to help diagnose intracranial stenosis in a cost-effective manner. Methods/Design: The Karachi Intracranial Stenosis Study (KISS) is a prospective, observational, case-control study to describe the clinical features and determine the risk factors of patients with stroke due to intracranial stenosis and compare them to those with stroke due to other etiologies as well as to unaffected individuals. We plan to recruit 200 patients with stroke due to intracranial stenosis and two control groups each of 150 matched individuals. The first set of controls will include patients with ischemic stroke that is due to other atherosclerotic mechanisms specifically lacunar and cardioembolic strokes. The second group will consist of stroke free individuals. Standardized interviews will be conducted to determine demographic, medical, social, and behavioral variables along with baseline medications. Mandatory procedures for inclusion in the study are clinical confirmation of stroke by a healthcare professional within 72 hours of onset, 12 lead electrocardiogram, and neuroimaging. In addition, lipid profile, serum glucose, creatinine and HbA1C will be measured in all participants. Ancillary tests will include carotid ultrasound, transcranial doppler and magnetic resonance or computed tomography angiogram to rule out concurrent carotid disease. Echocardiogram and other additional investigations will be performed at these centers at the discretion of the regional physicians. Discussion: The results of this study will help inform locally relevant clinical guidelines and effective public health and individual interventions

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Global, regional, and national burden of traumatic brain injury and spinal cord injury, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016.

Traumatic brain injury (TBI) and spinal cord injury (SCI) are increasingly recognised as global health priorities in view of the preventability of most injuries and the complex and expensive medical care they necessitate. We aimed to measure the incidence, prevalence, and years of life lived with disability (YLDs) for TBI and SCI from all causes of injury in every country, to describe how these measures have changed between 1990 and 2016, and to estimate the proportion of TBI and SCI cases caused by different types of injury. METHODS: We used results from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study 2016 to measure the global, regional, and national burden of TBI and SCI by age and sex. We measured the incidence and prevalence of all causes of injury requiring medical care in inpatient and outpatient records, literature studies, and survey data. By use of clinical record data, we estimated the proportion of each cause of injury that required medical care that would result in TBI or SCI being considered as the nature of injury. We used literature studies to establish standardised mortality ratios and applied differential equations to convert incidence to prevalence of long-term disability. Finally, we applied GBD disability weights to calculate YLDs. We used a Bayesian meta-regression tool for epidemiological modelling, used cause-specific mortality rates for non-fatal estimation, and adjusted our results for disability experienced with comorbid conditions. We also analysed results on the basis of the Socio-demographic Index, a compound measure of income per capita, education, and fertility. FINDINGS: In 2016, there were 27·08 million (95% uncertainty interval [UI] 24·30-30·30 million) new cases of TBI and 0·93 million (0·78-1·16 million) new cases of SCI, with age-standardised incidence rates of 369 (331-412) per 100 000 population for TBI and 13 (11-16) per 100 000 for SCI. In 2016, the number of prevalent cases of TBI was 55·50 million (53·40-57·62 million) and of SCI was 27·04 million (24·98-30·15 million). From 1990 to 2016, the age-standardised prevalence of TBI increased by 8·4% (95% UI 7·7 to 9·2), whereas that of SCI did not change significantly (-0·2% [-2·1 to 2·7]). Age-standardised incidence rates increased by 3·6% (1·8 to 5·5) for TBI, but did not change significantly for SCI (-3·6% [-7·4 to 4·0]). TBI caused 8·1 million (95% UI 6·0-10·4 million) YLDs and SCI caused 9·5 million (6·7-12·4 million) YLDs in 2016, corresponding to age-standardised rates of 111 (82-141) per 100 000 for TBI and 130 (90-170) per 100 000 for SCI. Falls and road injuries were the leading causes of new cases of TBI and SCI in most regions. INTERPRETATION: TBI and SCI constitute a considerable portion of the global injury burden and are caused primarily by falls and road injuries. The increase in incidence of TBI over time might continue in view of increases in population density, population ageing, and increasing use of motor vehicles, motorcycles, and bicycles. The number of individuals living with SCI is expected to increase in view of population growth, which is concerning because of the specialised care that people with SCI can require. Our study was limited by data sparsity in some regions, and it will be important to invest greater resources in collection of data for TBI and SCI to improve the accuracy of future assessments

Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

Burden of injury along the development spectrum : associations between the Socio-demographic Index and disability-adjusted life year estimates from the Global Burden of Disease Study 2017

Background The epidemiological transition of non-communicable diseases replacing infectious diseases as the main contributors to disease burden has been well documented in global health literature. Less focus, however, has been given to the relationship between sociodemographic changes and injury. The aim of this study was to examine the association between disability-adjusted life years (DALYs) from injury for 195 countries and territories at different levels along the development spectrum between 1990 and 2017 based on the Global Burden of Disease (GBD) 2017 estimates. Methods Injury mortality was estimated using the GBD mortality database, corrections for garbage coding and CODEm-the cause of death ensemble modelling tool. Morbidity estimation was based on surveys and inpatient and outpatient data sets for 30 cause-of-injury with 47 nature-of-injury categories each. The Socio-demographic Index (SDI) is a composite indicator that includes lagged income per capita, average educational attainment over age 15 years and total fertility rate. Results For many causes of injury, age-standardised DALY rates declined with increasing SDI, although road injury, interpersonal violence and self-harm did not follow this pattern. Particularly for self-harm opposing patterns were observed in regions with similar SDI levels. For road injuries, this effect was less pronounced. Conclusions The overall global pattern is that of declining injury burden with increasing SDI. However, not all injuries follow this pattern, which suggests multiple underlying mechanisms influencing injury DALYs. There is a need for a detailed understanding of these patterns to help to inform national and global efforts to address injury-related health outcomes across the development spectrum.Peer reviewe