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In this prospective, longitudinal study, we examined the risk factors for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among a cohort of chronic hemodialysis (HD) patients and healthcare personnel (HCPs) over a 6-month period. The risk of SARS-CoV-2 infection among HD patients and HCPs was consistently associated with a household member having SARS-CoV-2 infection.
Patients on dialysis are at high risk for severe COVID-19 and associated morbidity and mortality. We examined the humoral response to SARS-CoV-2 mRNA vaccine BNT162b2 in a maintenance dialysis population.
Single-center cohort study.
Setting and participants:
Adult maintenance dialysis patients at 3 outpatient dialysis units of a large academic center.
Participants were vaccinated with 2 doses of BNT162b2, 3 weeks apart. We assessed anti–SARS-CoV-2 spike antibodies (anti-S) ∼4–7 weeks after the second dose and evaluated risk factors associated with insufficient response. Definitions of antibody response are as follows: nonresponse (anti-S level, <50 AU/mL), low response (anti-S level, 50–839 AU/mL), and sufficient response (anti-S level, ≥840 AU/mL).
Among the 173 participants who received 2 vaccine doses, the median age was 60 years (range, 28–88), 53.2% were men, 85% were of Black race, 86% were on in-center hemodialysis and 14% were on peritoneal dialysis. Also, 7 participants (4%) had no response, 27 (15.6%) had a low response, and 139 (80.3%) had a sufficient antibody response. In multivariable analysis, factors significantly associated with insufficient antibody response included end-stage renal disease comorbidity index score ≥5 and absence of prior hepatitis B vaccination response.
Although most of our study participants seroconverted after 2 doses of BNT162b2, 20% of our cohort did not achieve sufficient humoral response. Our findings demonstrate the urgent need for a more effective vaccine strategy in this high-risk patient population and highlight the importance of ongoing preventative measures until protective immunity is achieved.
Elective surgical patients routinely bathe with chlorhexidine gluconate (CHG) at home days prior to their procedures. However, the impact of home CHG bathing on surgical site CHG concentration is unclear. We examined 3 different methods of applying CHG and hypothesized that different application methods would impact resulting CHG skin concentration.
The objective of this investigation was to utilize the first-principles molecular dynamics computational approach to investigate the lithiation characteristics of empty silicon clathrates (Si46) for applications as potential anode materials in lithium-ion batteries. The energy of formation, volume expansion, and theoretical capacity were computed for empty silicon clathrates as a function of Li. The theoretical results were compared against experimental data of long-term cyclic tests performed on half-cells using electrodes fabricated from Si46 prepared using a Hofmann-type elimination–oxidation reaction. The comparison revealed that the theoretically predicted capacity (of 791.6 mAh/g) agreed with experimental data (809 mAh/g) that occurred after insertion of 48 Li atoms. The calculations showed that overlithiation beyond 66 Li atoms can cause large volume expansion with a volume strain as high as 120%, which may correlate to experimental observations of decreasing capacities from the maximum at 1030 mAh/g to 553 mA h/g during long-term cycling tests. The finding suggests that overlithiation beyond 66 Li atoms may have caused damage to the cage structure and led to lower reversible capacities.
Several processing methods were developed and evaluated for synthesizing empty silicon clathrates. A solution synthesis method based on the Hofmann-elimination oxidation reaction was successfully utilized to produce 20 mg of empty Si46. Half-cells using the Si46 electrodes were successfully cycled for 1000 cycles at rate of 5.3C. The capacity of the Si46 electrode in long-term tests was 675 mAh/g at the 4th cycle, but increased to 809 mAh/g at 50 cycles. The corresponding Coulombic efficiency was better than 99%. The capacity dropped from 809 to 553 mAh/g after 1000 cycles while maintaining a 99% Coulombic efficiency. In comparison, a Ba8Al8Si38 electrode could be cycled for about 200 cycles with a lower capacity and Coulombic efficiency. Potential applications of empty silicon clathrates as anode materials in Li-ion batteries are discussed.
To evaluate whether food behaviours of parents are associated with children's dietary intakes outside the child-care setting, and to compare children's dietary intakes at home with foods and beverages consumed when they are at child-care centres.
In 2005–2006, a survey was completed by parents of at least one child between 3 and 5 years old who attended group child-care centres. Surveys about nutrition practices were completed by centre directors. Research assistants observed foods and beverages consumed by children at lunchtime at the centres.
Sixteen licensed group child-care centres in three underserved New York City communities (South Bronx, East/Central Harlem, Central Brooklyn) and the Lower East Side of Manhattan.
Two hundred parents.
Children were more likely to consume healthful foods including fruits or vegetables if parents reported purchasing food from produce stands/farmers’ markets, shopped for frozen or canned fruits frequently and ate family meals or meals prepared at home daily. Children were more likely to consume less healthful foods such as French fries, or fruit drinks, more frequently if parents reported eating meals from fast-food or other restaurants at least once weekly, or if children ate while watching television. Types of foods and beverages offered to children at home (e.g. higher-fat milk, soft drinks and desserts) were less healthful than those offered at child-care centres.
Children's dietary intakes at home need to be improved. Parents need to understand the importance of providing home environments that support healthful food behaviours in children.
Five hundred five blood cultures collected through a peripheral intravenous catheter (PIV) in an emergency department were matched to cultures obtained by dedicated venipuncture from the same patient within 10 minutes. The relative risk of contamination for cultures collected through PIVs compared with dedicated venipuncture was 1.83 (95% confidence interval, 1.08–3.11).
Prior research in political science and other disciplines demonstrates the pedagogical and practical benefits of active learning. Less is known, however, about the extent to which active learning is used in political science classrooms. This study assesses the prioritization of active learning in “gateway” political science courses, paying specific attention to simulations, structured debates, and the case method. Nearly five hundred individual course syllabi for introductory-level political science courses are examined. Although the level of active learning prioritization is surprisingly low, the dimensions on which it varies suggest opportunities for adoption across subfields and classes of varying size.
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