66 research outputs found

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Advances In Radiologic Imaging Of Neonatal Airway Disorders

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    Radiology of the airways in newborns and infants is challenging due the small size of their anatomy, their inability to follow breathing instructions, and the concern for long-term effects of radiation exposure. While some patients can be managed with observation or empiric therapy, for other patients the diagnosis may remain uncertain, and imaging is an essential part of management. Radiology serves to detect airway abnormalities, guide therapy, assist with preoperative planning, and help avoid invasive testing

    Racial, Socioeconomic, and Payer Status Disparities in Utilization of Total Ankle Arthroplasty Compared with Ankle Arthrodesis

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    Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle arthroplasty is increasingly being used for the treatment of ankle osteoarthritis when compared to arthrodesis. However, there has been limited investigation into disparities in utilization of these comparable procedures. This study examined racial/ethnic, socioeconomic, and payer status disparities in the likelihood of undergoing total ankle arthroplasty compared with ankle arthrodesis. Methods: Patients with a diagnosis of ankle osteoarthritis from 2006 through 2019 were identified in the National Inpatient Sample, then subclassified as undergoing total ankle arthroplasty or arthrodesis. Multivariable logistic regression models, adjusted for hospital location, total hospital charges, primary or secondary osteoarthritis diagnosis, and patient characteristics (age, sex, infection, diabetes, neuropathy, and Elixhauser Comorbidity Index), were used to examine the effect of race/ethnicity, socioeconomic status, and payer status on the likelihood of undergoing total ankle arthroplasty versus arthrodesis. Results: There were 6,966 patients who underwent TAA and 5,681 patients who underwent arthrodesis over the study period. Black and Hispanic patients were 42% and 32% less likely than White patients to undergo total ankle arthroplasty rather than arthrodesis (P <.001). Patients in income quartiles 3 and 4 were 17% and 23% more likely, respectively, than patients in quartile 1 (the lowest quartile) to undergo total ankle arthroplasty rather than arthrodesis (P=.001 and P=0.01, respectively). Privately insured and Medicare patients were 67% and 117% more likely, respectively, than Medicaid patients to undergo total ankle arthroplasty rather than arthrodesis (P <.001). Conclusion: Racial/ethnic, socioeconomic, and payer status disparities exist in the likelihood of undergoing total ankle arthroplasty versus arthrodesis for ankle osteoarthritis. More work is needed to establish drivers of these disparities and identify targets for intervention, including improvements in parity in relative procedure utilization

    Superconducting beam charge monitors for antiproton storage rings

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    A Cryogenic Current Comparator (CCC) is a new type of instruments for monitoring charged beams like ions or antiprotons. Using superconducting effects is it possible to create a nondestructive, contactless and easy to calibrate beam measurement system with a high current resolution in amplitude and time. The Meissner effect enables an effective magnetic shielding of the system. The screening current enables creation of DC-transformers and therefore a DC-current measurement system. The combination of two Josephson-junctions and coils form a superconducting quantum interference device (SQUID) in an analog magnetic feedback of the flux-locked loop (FLL), which is linearizing the SQUID’s transfer function. The performance of the CCC system opens beam currents range between 1 nA and 20 µA. Installations at the Antiproton Decelerator at CERN and GSI in Darmstadt shows a strong correlation between SEM/longitudinal-Schottky and CCC signals including the known spill pattern but with a better signal to noise ratio
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