Investigation of baffle configuration effect on the performance of exhaust mufflers

Using baffles in exhaust mufflers is known to improve their transmission loss. The baffle cut ratio should affect the muffler performance analogous to a shell-and-tube heat exchanger. To the authors’ knowledge, there is no previous assessment reported in literature of the effects that the baffle cut ratio configuration has on acoustic response and back pressure. This investigation presents a parametric study on the effect of baffle configuration on transmission loss and pressure drop predicted. The effect of (i) the baffle cut ratio and baffle spacing, (ii) the number of baffle holes, and (iii) the hole distribution for their effect on transmission loss was investigated. Results show that decreasing the baffle cut ratio tends to increase the transmission loss at intermediate frequencies by up to 45%. Decreasing the spacing between muffler plates was shown to enhance the muffler transmission loss by 40%. To assess the baffle effect on flow, the OpenFoam CFD libraries were utilized using the thermal baffle approach model. Baffles were found to cause sudden drop in fluid temperature in axial flow direction. The outlet exhaust gases temperature was found to decrease by 15% as the baffle cut ratio changed from 75% to 25%

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

L-stability in Rings and Left Quasi-duo Rings

A ring R is said to have stable range 1 if, for any element a in R and any left ideal L of R, Ra+L=R implies a-u in L for some unit u in R. Here we insist only that this holds for all L in some non-empty set L(R) of left ideals of R, and say that R is left L-stable in this case. We say that a class C of rings is affordable if C is the class of left L-stable rings for some left idealtor L. In addition to the rings of stable range 1, it is known that the left uniquely generated rings and the rings with internal cancellation are both affordable. Here, we explore L-stability in general, derive some properties of this phenomenon and show that it captures many well-known results. This in turn yields new information about the left uniquely generated rings and the internally cancellable rings, and enables us to answer some open questions related to them. More importantly, we show that the directly finite rings are affordable, which gives a new perspective on these rings and the plethora of open questions related to them. Next, we turn to the class of left quasi-duo rings, that is, rings R in which every maximal left ideal is an ideal. But, surprisingly, these rings have many nice natural characterizations and properties that have passed unnoticed since they were introduced in 1995. Here we discuss this class of rings and prove some interesting new results for them. In particular, we introduce the notion of left width for rings, and use it to give a characterization of any left quasi-duo ring that has a finite left width. After that, a characterization of the I-finite left quasi-duo rings will be given. Finally, we introduce the left-max idealtor which is defined in terms of the maximal left ideals for any ring R. Then we study and characterize its associated rings which will be called the left-max stable rings. We also show that the class of left quasi-duo rings is neither left-max stable nor affordable

Improvement of generalized granuloma annulare with adalimumab: A case report

Granuloma annulare is a benign, inflammatory condition of unknown etiology, characterized by erythematous annular plaques, frequently on distal extremities. Generalized granuloma annulare can be difficult to treat, with varying success in therapeutic approaches. We present the case of a 59-year-old female with refractory generalized granuloma annulare successfully managed with adalimumab, requiring ongoing 40 mg q2weekly treatment for 2 years. While there are a handful of published case reports/series suggesting that adalimumab can be used to treat generalized granuloma annulare, dosing regimens and the need for long-term use remain inconsistent. This case adds further evidence for considering adalimumab as a sustained therapeutic option for recalcitrant generalized granuloma annulare. The patient responded to adalimumab, a tumor necrosis factor-alpha antagonist, administered biweekly for a year, then switched to weekly intervals. Most granuloma annulare lesions improved within 2 months and continued to improve throughout the treatment. Adalimumab may be proposed as a therapeutic treatment for recalcitrant forms of generalized granuloma annulare

Risk of error estimated from Palestine pharmacists’ knowledge and certainty on the adverse effects and contraindications of active pharmaceutical ingredients and excipients

Purpose: This study aimed to investigate community pharmacists’ knowledge and certainty of adverse effects and contraindications of pharmaceutical products to estimate the risk of error. Factors influencing their knowledge and certainty were also investigated. Methods: The knowledge of community pharmacists was assessed in a cross-sectional design using a multiple-choice questions test on the adverse effects and contraindications of active pharmaceutical ingredients and excipients from May 2014 to March 2015. Self-rated certainty scores were also recorded for each question. Knowledge and certainty scores were combined to estimate the risk of error. Results: Out of 315 subjects, 129 community pharmacists (41.0%) completed the 30 multiple-choice questions test on active ingredients and excipients. Knowledge on active ingredients was associated with the year of graduation and obtaining a licence to practice pharmacy. Knowledge on excipients was associated with the degree obtained. There was higher risk of error in items on excipients than those on ingredients (P<0.01). Conclusion: The knowledge of community pharmacists in Palestine was insufficient with high risk of errors. Knowledge of community pharmacists on the safety issues of active ingredients and excipients need to be improved

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

Background: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit