Spectroscopy 21 (2007) 193-204 193 IOS Press Molecular dynamics in calf-thymus DNA, at neutral and low pH, in the presence of Na + , Ca 2+ and Mg 2+ ions: A Raman microspectroscopic study

Abstract. In this paper the Raman total half bandwidths of calf-thymus DNA vibrations have been measured as a function of pH, monovalent and divalent cations' type and concentration. The dependence of different band parameters on DNA molecular subgroup structure, on pH and on Na + , Ca 2+ and Mg 2+ ions concentrations, respectively, are reported. It is shown that changes in (sub)picosecond dynamics of molecular subgroups in calf-thymus DNA can be monitored with confocal Raman microspectroscopy. The half bandwidths and the global relaxation times for the vibrations at 728 cm (PO 2 − ), 1377 cm −1 (dA, dG, dT, dC), 1488 cm −1 (dG, dA) and 1580 cm −1 (dG, dA) of calf-thymus DNA are presented. The full-widths at half-height (FWHH) of the bands in calf-thymus DNA are typically in the wavenumber range from 7.4 to 31 cm −1 . The bandwidths in the Raman spectra are sensitive to a dynamics active on a time scale from 0.34 to 1.44 ps. Low pH-induced melting of double helical structure in calf-thymus DNA results for some bands in shorter global relaxation times, as a consequence of the increased interaction of the base moieties with the solvent molecules. The molecular dynamics characterizing the 785, 1094, 1377 and 1580 cm −1 vibrations, is faster in the case of high divalent cations DNA sample (pH 7), as compared to the respective low divalent cations DNA sample (pH 7), for both Ca 2+ and Mg 2+ ions. The vibrational energy transfer process of the guanine band at 1488 cm −1 is slower for the high salt DNA sample, pH 7 as compared to the corresponding low salt DNA sample, pH 7, for both Ca 2+ and Mg 2+ . Molecular dynamics characterizing the vibration at 1488 cm −1 is faster for DNA sample at high Na + ions (pH 7), as compared to the DNA sample at low Na + ions (pH 7). As far as the CaDNA and MgDNA complexes are concerned (pH 7), the global relaxation times of some base vibrations decrease for the case of magnesium ions, as compared to the case of the same concentration of calcium ions. The different ionic radius of the two types of metal cations (0.72 Å for Mg and 0.99 Å for Ca) were considered in explaining these results. Molecular relaxation processes of DNA subgroups, upon lowering the pH, in the presence of Na + , Ca 2+ and Mg 2+ ions are presented. Particularly, at low Ca 2+ concentration, upon lowering the pH, the molecular dynamics of DNA subgroups corresponding to vibrations at 728, 1376, 1488 and 1580 cm −1 is much faster, probably due to the denaturation process of the double helical DNA

Acute Viral Hepatitis A – Clinical, Laboratory and Epidemiological Characteristics

Background and Aims: Infection with hepatitis A virus is still one of the most common causes of hepatitis worldwide. The clinical manifestation of acute hepatitis A (AHA) in adults can vary greatly, ranging from asymptomatic infection to severe and fulminant hepatitis. The aim of this study was to describe the demographic, clinical characteristics, laboratory features and hospital outcome of adult patients with AHA over a consecutive period of 4 years within an area from Eastern European country. Methods: Two hundred and two adult patients diagnosed with AHA were retrospective, observational and analytic analized over a period of 4 years. Based on prothrombin time less than 50, the study group was stratified in medium (79.2%) and severe forms (20.8%). We investigated the clinical, laboratory and epidemiological features. Statistical analysis were applied to compare the medium and severe forms of AHA. Results: Most patients (72.7%) were younger than 40 years. The main symptoms included: dyspepsia (72.07%), jaundice (86.63%), asteno-adynamia (86.72%), and flu-like symptoms (53.46%). The hemorrhagic cutaneous-mucous manifestations (6.93%) associated with the severe forms of AHA (OR =12.19, 95%CI -3.59 - 41.3, p =0.001). We found statistically significant differences for PT (p <0.001), INR (p <0.001), TQ (p <0.001), ALAT (p <0.001), ASAT (p <0.001), ALP (p <0.001) and platelets (p =0.009) between severe and medium AHA forms. We found that TQ, INR, ALAT and ASAT have the highest diagnostic values, statistically significant (p <0.05 ) for severe AHA forms with AUC (0.99, 0.99, 0.72, 0.70) at values of sensitivity (95%, 90.5%, 89%, 95%) and specificity (98%, 99%, 88%,94%). Conclusions Medium severity AHA forms were found in most of the study group patients (79.2%). The severe AHA forms were associated with hemorrhagic cutaneous-mucous manifestations (OR =12.19, p =0.001). The univariate analysis proved a negatively statistically significant correlation between IP and ALAT, ASAT. The present study revealed that TQ, INR and ALAT have the highest diagnostic values and are statistically significant for severe AHA forms

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

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

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

An analysis of flip classroom pedagogy in first year undergraduate mathematics for computing

Mathematics is a key subject for success in Computer Science and it continues to be a challenging subject. Use of technology has given rise to a new pedagogy called Flip-Classroom (FC). FC involves creating online multimedia content that is utilized out-of-class in conjunction with in-class learning activities such as individual and collaborative problem solving, group-work and class-discussion. An experiment was conducted to investigate the utility of FC pedagogy and its relationship with student learning. FC pedagogy was implemented in a first year "Introduction to Mathematics for Computing" module and was employed for a number of core topics. A traditional lecture approach was utilized for the remaining topics. In-class quiz based assessments, homework assignments and end of semester examinations have been performed in order to assess the learning performance of the students. The results show that on average students performed better in assessments on topics taught through FC pedagogy. For Continuous Assessment (CA) components this increase was 14% and for the terminal exam this increase was 21%. The results indicate that the FC pedagogy may improve learning. Furthermore the students have indicated their preference in favor of FC pedagogy. This study will be of interest to those considering integrating FC pedagogy into teaching Mathematics