A fractional factorial design was used to measure the effects and interactions of temperature (12-37 degrees C), initial pH (5.5-7.5), NaCl (0.5-4.0%) and NaNO2 (0-1000 ppm) on the anaerobic growth kinetics of Shigella flexneri in Brain-Heart Infusion broth. Anaerobic conditions were established by flushing the culture flasks with N2. A total of 375 cultures representing 124 variable combinations were analyzed, with growth curves being generated using the Gompertz equation. Growth rates decreased with decreasing temperature, decreasing pH and increasing NaCl level. NaNO2 in combination with low temperature, low pH and high NaCl content effectively inhibited S. flexneri. Response surface analysis was used to obtain models for estimating the growth of S. flexneri in terms of temperature, initial pH, and NaCl and NaNO2 concentrations. A third-order equation using the natural logarithm transformations for the Gompertz B and M terms gave reasonable estimates of bacterial growth in response to any combination of the variables studied within the specified ranges.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/0168-1605(94)90162-7 | DOI Listing |
Small Methods
January 2025
BCMaterials, Basque Centre for Materials, Applications and Nanostructures; UPV/EHU Science Park, Leioa, 48940, Spain.
Carbon coating on SiO surface is crucial for enhancing initial Coulombic efficiency (ICE) and cycling performance in batteries, while also buffering volume expansion. Despite its market prevalence, the effects of the carbon layer's quality and structure on the electrochemical properties of SiO remain underexplored. This study compares carbon layers produced via gas-phase and solid-phase coating methods, introducing an innovative technique that sequentially uses two gases to develop a low-impedance hybrid carbon structure.
View Article and Find Full Text PDFUndersea Hyperb Med
January 2025
Graduate Program in Veterinary Medicine, Center of Rural Science, Federal University of Santa Maria (UFSM), Av. Roraima, 1000, building 42, room 3135, 97105-900 Santa Maria, RS, Brazil.
The assessment of rectal temperature and behavior is an important parameter in all patients for whom hyperbaric oxygen (HBO) therapy is used. The study aims to verify if there is less reduction in body temperature after HBO therapy in restless patients and their behavior during the therapeutic session. Clinical data from 217 HBO therapy sessions with 2 to 2,5 atmospheres absolute (ATA) were reviewed under therapy protocols of 30 (P1) or 45 (P2) minutes, covering 29 canines and 13 felines.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
Department of Mechatronics and Mechanical Systems Engineering, University of São Paulo, São Paulo, SP 05508-030, Brazil.
Labyrinth seals (LSs) in turbomachinery are used to minimize leaks. This study presents an experimental setup designed to test and validate LS designs. The test bench (TB) described in this paper can evaluate different LS designs obtained through various methods to find better solutions to mitigate greenhouse gas (GHG) emissions.
View Article and Find Full Text PDFPLoS One
January 2025
School of Mechanical Engineering, Liaoning Technical University, Fuxin, China.
Titanium alloy is known for its low thermal conductivity, small elastic modulus, and propensity for work hardening, posing challenges in predicting surface quality post high-speed milling. Since surface quality significantly influences wear resistance, fatigue strength, and corrosion resistance of parts, optimizing milling parameters becomes crucial for enhancing service performance. This paper proposes a milling parameter optimization method utilizing the snake algorithm with multi-strategy fusion to improve surface quality.
View Article and Find Full Text PDFMicrob Ecol
January 2025
Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Sciences, Liaoning Normal University, Dalian, 116029, China.
Temperate estuary wetlands act as natural filters for microbiological contamination and have a profound impact on "One Health." However, knowledge of microbiological ecology security across the different habitats in temperate estuarine wetlands remains limited. This study employed meta-analysis to explore the characteristics of bacterial communities, potential pathogens, and antibiotic resistance genes (ARGs) across three heterogeneous habitats (water, soil, and sediment) within the Liaohe Estuary landscape.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!