ABSTRACT
A physical chemistry lab for undergraduate students described in this report is about applying kinetic models to analyze the spread of COVID-19 in the United States and obtain the reproduction numbers. The susceptible-infectious-recovery (SIR) model and the SIR-vaccinated (SIRV) model are explained to the students and are used to analyze the COVID-19 spread data from U.S. Centers for Disease Control and Prevention (CDC). The basic reproduction number R 0 and the real-time reproduction number R t of COVID-19 are extracted by fitting the data with the models, which explains the spreading kinetics and provides a prediction of the spreading trend in a given state. The procedure outlined here shows the differences between the SIR model and the SIRV model. The SIRV model considers the effect of vaccination which helps explain the later stages of the ongoing pandemic. The predictive power of the models is also shown giving the students some certainty in the predictions they made for the following months.
ABSTRACT
BACKGROUND: Single irrigation of the peri-implant space with a cefazolin-based triple antibiotic solution is a routine antibiotic prophylaxis measure during implant-based breast augmentation and reconstruction. Cefazolin, however, is less efficacious against resistant Staphylococcus species, which are the predominant bacterial species isolated from the peri-implant space. Vancomycin is effective against resistant Staphylococcus species and may be a more appropriate prophylactic agent. The availability of single-injection long-acting anesthetic agents allows the novel use of the elastomeric infusion pump for continuous irrigation of antibiotic solution into the peri-implant space. The efficacy of continuous irrigation with a vancomycin-based solution is evaluated here. METHODS: Study patients (N = 163; group 1) who underwent immediate, direct-to-implant breast reconstruction received continuous infusion of a vancomycin-based triple antibiotic solution. Patients also received a single injection of liposomal bupivacaine in the pectoralis major/minor muscles for pain control. A historic control group (N = 113; group II) received ropivacaine local anesthetic via the infusion pump and a single intraoperative irrigation of the peri-implant space with the vancomycin-based triple antibiotic solution. Incidence of postsurgical infection during the 6 weeks after surgery was compared between the groups. RESULTS: Group I patients had a statistically significant lower incidence of infections (1.9%) than group II patients (6.4%) (P = 0.007). There were no vancomycin-related adverse effects. CONCLUSIONS: Continuous breast irrigation with a vancomycin-based triple antibiotic solution is a safe and effective accompaniment for immediate implant reconstruction. Use of intramuscular anesthetic injection for postoperative pain control allows the elastomeric infusion pump to be available for local tissue antibiotic irrigation.
ABSTRACT
The main objective of this research was to test the hypothesis that bioavailable protein and, more specifically, the sulfur-containing amino acids within the protein, can be degraded by proteolytic enzymes to produce odor-causing compounds--mainly volatile sulfur compounds (VSCs)--during biosolids storage. To achieve these objectives, samples of digester effluent and cake solids were collected at 11 different wastewater treatment plants in North America, and the samples were analyzed for protein and amino acid content and general protein-degrading enzyme activity. At the same time, cake samples were stored using headspace bottles, the concentration of VSCs were measured using gas chromatography, and olfactometry measurements were made by a trained odor panel. The results showed that the bound cake protein content and methionine content was well-correlated with VSC production and the detection threshold measured by the odor panel.
