Linear Wavefield Optimization Using a Modified Source

Recorded seismic data are sensitive to the Earth's elastic properties, and thus, they carry information of such properties in their waveforms. The sensitivity of such waveforms to the properties is nonlinear causing all kinds of difficulties to the inversion of such properties. Inverting directly for the components forming the wave equation, which includes the wave equation operator (or its perturbation), and the wavefield, as independent parameters enhances the convexity of the inverse problem. The optimization in this case is provided by an objective function that maximizes the data fitting and the wave equation fidelity, simultaneously. To enhance the practicality and efficiency of the optimization, I recast the velocity perturbations as secondary sources in a modified source function, and invert for the wavefield and the modified source function, as independent parameters. The optimization in this case corresponds to a linear problem. The inverted functions can be used directly to extract the velocity perturbation. Unlike gradient methods, this optimization problem is free of the Born approximation limitations in the update, including single scattering and cross talk that may arise for example in the case of multi sources. These specific features are shown for a simple synthetic example, as well as the Marmousi model.     

Potential routes for indirect transmission of African swine fever virus into domestic pig herds

Following its introduction into Georgia in 2007, African swine fever virus (ASFV) has become widespread on the European continent and in Asia. In many cases, the exact route of introduction into domestic pig herds cannot be determined, but most introductions are attributed to indirect virus transmission. In this review, we describe knowledge gained about different matrices that may allow introduction of the virus into pig herds. These matrices include uncooked pig meat, processed pig‐derived products, feed, matrices contaminated with the virus and blood‐feeding invertebrates. Knowledge gaps still exist, and both field studies and laboratory research are needed to enhance understanding of the risks for ASFV introductions, especially via virus‐contaminated materials, including bedding and feed, and via blood‐feeding, flying insects. Knowledge obtained from such studies can be applied to epidemiological risk assessments for the different transmission routes. Such assessments can be utilized to help predict the most effective biosecurity and control strategies.     

Community pharmacists’ knowledge,behaviors and experiences about adverse drug reaction reporting in Saudi Arabia

Objective

To assess community pharmacists’ knowledge, behaviors and experiences relating to Adverse Drug Reaction (ADR) reporting in Saudi Arabia.

Methods

A cross-sectional study was conducted using a validated self-administered questionnaire. A convenience sample of 147 community pharmacists working in community pharmacies in Riyadh, Saudi Arabia.

Results

The questionnaire was distributed to 147 pharmacists, of whom 104 responded to the survey, a 70.7% response rate. The mean age of participants was 29 years. The majority (n = 101, 98.1%) had graduated with a bachelorette degree and worked in chain pharmacies (n = 68, 66.7%). Only 23 (22.1%) said they were familiar with the ADR reporting process, and only 21 (20.2%) knew that pharmacists can submit ADR reports online. The majority of the participants (n = 90, 86.5%) had never reported ADRs. Reasons for not reporting ADRs most importantly included lack of awareness about the method of reporting (n = 22, 45.9%), misconception that reporting ADRs is the duty of physician and hospital pharmacist (n = 8, 16.6%) and ADRs in community pharmacies are simple and should not be reported (n = 8, 16.6%). The most common approach perceived by community pharmacists for managing patients suffering from ADRs was to refer him/her to a physician (n = 80, 76.9%).

Conclusion

The majority of community pharmacists in Riyadh have poor knowledge of the ADR reporting process. Pharmacovigilance authorities should take necessary steps to urgently design interventional programs in order to increase the knowledge and awareness of pharmacists regarding the ADR reporting process.     

Antidiabetic drugs and non-alcoholic fatty liver disease: A systematic review,meta-analysis and evidence map

BackgroundThe efficacy of antidiabetic agents for the treatment of non-alcoholic fatty liver disease (NAFLD) remains unclear.AimTo conduct a meta-analysis to study the efficacy of pioglitazone and three novel anti-diabetic agents: glucagon-like peptide-1 (GLP-1) agonists, sodium-glucose co-transporter-2 (SGLT2) inhibitors, and dipeptidyl-peptidase-4 (DPP4) inhibitors in treating NAFLD.MethodsOnline databases were searched in May 2020 for randomized clinical trials. Results from random-effects meta-analysis are presented as weighted mean differences (WMDs) or standard mean differences (SMDs) and corresponding 95% confidence intervals (CIs).ResultsTwenty-six studies (n=946 NAFLD patients) were included. Reductions in ALT were seen with all four drugs: pioglitazone (MD -38.41, p<0.001), SGLT2 inhibitors (MD -16.17, p<0.001), GLP-1 agonists (MD -27.98, p=0.04) and DPP-4 inhibitors (MD -7.41, p<0.001). Pioglitazone (SMD -1.01; p<0.001) and GLP-1 agonists (SMD -2.53, p=0.03) also demonstrated significant improvements in liver steatosis. SGLT2 inhibitors (SMD -4.64, p=0.06) and DPP-4 (SMD -2.49, p=0.06) inhibitors trended towards reduced steatosis; however, these results were non-significant.ConclusionPioglitazone demonstrates significant improvements in transaminases and liver histology in both diabetic and non-diabetic NAFLD patients. Early evidence from diabetic NAFLD patients suggests that novel antidiabetics may lead to improvements in liver enzymes and hepatic steatosis, and this should encourage further research into possible utility of these drugs in treating NAFLD.     

Colonic malacoplakia and abdominal tuberculosis in a child

A 41/2-year-old girl had colonic malacoplakia of two years' duration, the presenting symptom being rectal bleeding. Abdominal tuberculosis andEscherichia coli lumbar abscess were diagnosed at the age of 31/2 years. Despite antituberculous treatment, there was no improvement and she died from protein-losing enteropathy. The patient is discussed and the literature reviewed, with special emphasis on the incidence of malacoplakia in children, the aggressive nature of colonic malacoplakia, and the lack of response to treatment. A brief review of the pathogenesis of malacoplakia is considered.     

The ultrastructure of mantle cell lymphoma and other B-cell disorders with translocation t(11;14)(q13;q32)

We conducted an ultrastructural study in 22 cases of B-lymphoproliferative disorders in leukaemic phase bearing the t(11;14) translocation. The features of peripheral blood leukaemic cells in nine cases of mantle cell lymphoma (MCL) were compared to those diagnosed as B-prolymphocytic leukaemia (B-PLL) (five cases), splenic lymphoma with villous lymphocytes (SLVL) (four cases), lymphoplasmocytic lymphoma (LPL) (one case), chronic lymphocytic leukaemia with >10% prolymphocytes (CLL/PL) (one case) and unclassified B-non Hodgkin's lymphoma (B-NHL) (two cases). The ultrastructural characteristics were also compared to those present in B-NHL without t(11;14), including cases of follicular centre lymphoma (FCL). This study shows that MCL has distinct ultrastructural features including a cleaved or indented nucleus with an even heterochromatin distribution, an absent or inconspicuous nucleolus, low N/C ratio, abundant mitochondria, a well developed Golgi zone, profiles of endoplasmic reticulum and centrioles. This pattern clearly differs from that found in FCL cells. The nuclear pattern of MCL cells also differed from the cells in the other disorders with t(11;14), but shared an organelle-rich cytoplasm, and features which were not apparent in cases without t(11;14). The cytoplasmic changes observed in cells bearing t(11;14) suggest increased cellular activity which may relate to the chromosome translocation and the resulting over-expression of bcl-1.     

Plurihormonal pituitary adenoma with concomitant adrenocorticotropic hormone (ACTH) and growth hormone (GH) secretion: a report of two cases and review of the literature

Plurihormonal pituitary adenomas are tumours that show immunoreactivity for more than one hormone that cannot be explained by normal adenohypophysial cytodifferentiation. The most common combinations in these adenomas include growth hormone (GH), prolactin (PRL) and one or more glycoprotein hormone sub-units (β-TSH, β-FSH, β-LH and αSU). The authors report two cases of a plurihormonal pituitary adenoma expressing the rare combination of ACTH and GH. They both underwent successful transphenoidal hypophysectomy (TSH). Long-term post-operative follow-up revealed no evidence of tumour recurrence. Due to the multiple secretions and plurihormonal characteristics clinical diagnosis of composite pituitary adenomas can be difficult. The authors discuss the diagnosis and management of composite pituitary adenomas and review the literature regarding this rare phenomenon.     

Point-of-care testing versus standard practice for chlamydia: a new approach to assessing the public health effect of rapid testing and treatment at local level

BackgroundChlamydia trachomatis is the most commonly diagnosed bacterial sexually transmitted infection in Britain. Present standards specify treatment within 14 days of testing positive; point-of-care testing (POCT) can eliminate this delay and potentially reduce loss to follow-up; its greater convenience might increase testing. 90-min nucleic acid amplification tests are the best available POCTs for chlamydia, with alternatives under development. However, cost-effectiveness depends on cost-per-test, sensitivity and specificity, and the effect of POCT on transmission.MethodsWe developed a user-friendly web-based method, based on a transmission-dynamic model for chlamydia, to assess the epidemiological impact and cost-effectiveness of introducing POCT in different local settings. The model uses behavioural and prevalence data from the National Survey of Sexual Attitudes and Lifestyles, and Public Health England surveillance data; these data inform on local-level variation, which is represented by sampling parameter values from within their ranges of uncertainty and selecting parameter sets that reproduce local coverage and diagnosis rates. The user can select different local settings, and vary sensitivity and specificity for the tests, specify costs (fixed and unit costs, including staff time), and then assess the effect of introducing POCT in different clinical services by comparison with a situation with no POCT. In the model, presumptive treatment is represented, which we expect to be reduced with the introduction of POCT because test results would be rapidly available to guide treatment.FindingsChanges in numbers of infections and diagnoses occurring under different scenarios (including conventional testing) were estimated, with uncertainty ranges, allowing calculation of total costs, and cost per infection (and serious sequelae) averted, while accommodating the considerable variation in chlamydia testing coverage, positivity, and diagnosis rates. Potential changes in sexual behaviour between test and treatment could determine the relative contribution of increased treatment rates and reduced treatment delay to the reduction in prevalence as a consequence of POCT.InterpretationThe effect of POCT was dependent on both the test performance characteristics and the assumptions about the implementation of the test across local services. Exploration of many uncertainties surrounding chlamydia epidemiology and screening implementation is possible with this model. This method can complement local and national knowledge, and contribute to local-level management of chlamydia infection.FundingInnovate UK (Technology Strategy Board), UK Medical Research Council, and the National Institute for Health Research. The Electronic Self-Testing Instruments for Sexually Transmitted Infection (eSTI2) Consortium eSTI2 is Funded under the UKCRC Translational Infection Research (TIR) Initiative supported by the Medical Research Council (Grant Number G0901608) with contributions to the Grant from the Biotechnology and Biological Sciences Research Council, the National Institute for Health Research on behalf of the Department of Health, the Chief Scientist Office of the Scottish Government Health Directorates, and the Wellcome Trust