To characterise the occurrence of Cronobacter in milk powder factories. Cronobacter was isolated from 32% of 298 environmental samples from five factories. More isolations occurred in nonprocessing ...(49%) than processing areas (29%), although the greatest occurrence was in a single milk powder area during shutdown maintenance (81%) and the lowest after reinstatement of production hygiene practices (6%). Clonal analysis using PFGE placed 129 isolates into 49 groups. Most clones (45) were unique to each factory and seven were isolated in both milk powder and other areas of the same factory including tanker bays, evaporator rooms, an employee's shoes and external roofs. Cronobacter was not isolated from raw milk processing areas. Within powder areas, 17 clones occurred at more than one and up to eight locations and six occurred more than once at the same location. Between four and seven clones were in the powder areas at each factory. The most prevalent and persistent clones were isolated from external roofs above spray driers, in air treatment areas and where high foot traffic occurs. Cronobacter is dispersed widely at milk powder factories. This study suggests that distribution is assisted by movement of air, milk powder and personnel and that new hygiene strategies will be needed to reduce prevalence. Knowledge of occurrence is essential for the development of strategies to control dissemination of Cronobacter within factories and reduce risk of entry into powdered milk products.
Background
Information on steroids derived from the adrenal glands, gonads, or fetoplacental unit is minimal in newborn foals.
Objective
To measure androgen concentrations in serum and determine ...their association with disease severity and outcome in hospitalized foals.
Animals
Hospitalized (n = 145) and healthy (n = 80) foals.
Methods
Prospective, multicenter, cross‐sectional study. Foals of ≤3 days of age from 3 hospitals and horse farms were classified as healthy and hospitalized (septic, sick nonseptic, neonatal maladjustment syndrome NMS) based on physical exam, medical history, and laboratory findings. Serum androgen and plasma ACTH concentrations were measured with immunoassays. Data were analyzed by nonparametric methods and univariate analysis.
Results
Serum dehydroepiandrosterone (DHEA), androstenedione, testosterone, and dihydrotestosterone (DHT) concentrations were higher upon admission in hospitalized foals (P < .05), were associated with nonsurvival, decreased to 4.9‐10.8%, 5.7‐31%, and 30.8‐62.8% admission values in healthy, SNS, and septic foals, respectively (P < .05), but remained unchanged or increased in nonsurviving foals. ACTH:androgen ratios were higher in septic and NMS foals (P < .05). Foals with decreased androgen clearance were more likely to die (odds ratio > 3; P < .05).
Conclusions and Clinical Importance
Similar to glucocorticoids, mineralocorticoids, and progestagens, increased serum concentrations of androgens are associated with disease severity and adverse outcome in hospitalized newborn foals. In healthy foals, androgens decrease over time, however, remain elevated longer in septic and nonsurviving foals. Androgens could play a role in or reflect a response to disorders such as sepsis or NMS in newborn foals.
Key processes in (bio)electrochemistry involve multiple electron transfers. The study of the stability of the different oxidation states and the interaction between redox centers is fundamental to ...understand these processes. In this paper, simple analytical equations are presented for multielectron transfer processes in cyclic voltammetry (CV) and staircase cyclic voltammetry (SCV) at disc electrodes of any size. This provides a simple simulation method for the electrochemical response without demanding computing. The use of CV and SCV, and the corresponding differential techniques, for the characterization of these redox systems is analyzed. Procedures and criteria are given for transient and stationary conditions. The theoretical results are applied to the experimental study of the reduction of anthraquinone-2-sulfonate in water on gold macro- and microdisc electrodes.
We report the detection and characterisation of polymer nanoparticles using electrochemistry using poly(N‐vinylcarbazole) nanoparticles (PVK NPs) as a model system. These were synthesised using the ...reprecipitation method. The number of electrons (n=2) transferred per PVK monomer was characterised by drop‐casting method. Sticking and sensing experiments were then conducted, which involve PVK nanoparticle immobilisation on the electrode surface and subsequent oxidative sensing, to enable rapid detection of polymer nanoparticles in aqueous solution. It is shown for the first time, that using this “stick and sense” method, polymer nanoparticles in aqueous solution can be immobilised, preconcentrated and quantified.
Analytical explicit solutions are presented for the use of square wave voltammetry (SWV) at disc microelectrodes to study two-electron reversible redox processes. This combines the advantages of SWV ...(minimization of capacitative effects, peak-shaped response and quick experiments) with those of microelectrodes (reduction of capacitative and ohmic drop effects, enhanced mass transport and measurements of small volumes). Further, the analytical expressions are very easy to implement in comparison with the numerical methods usually employed for simulation of electrochemical experiments at microdisc electrodes. From the theory, the effects of the technique parameters (frequency, pulse amplitude) are examined and procedures are given for the characterization of the redox system from the values of the peak current, peak potential and half-peak width. Finally, the theory is applied to the experimental study of the two-electron reduction of anthraquinone-2-sulfonate in aqueous media. For this system, the formal potentials of the redox centres in aqueous solutions can be tuned by means of the electrolyte cation.
Analytical expressions are presented for the study of multi-electron transfer processes with SWV at disc microelectrodes.
•Modelling of degree of adiabaticity for diffusional electrode processes is considered.•A potential energy curve formalism has been employed in the kinetic model.•2-Nitropropane reduction on mercury ...is studied via temperature-variable voltammetry.•Cyclic voltammograms are recorded in DMSO solutions at temperatures 22.0–44.5°C.•The adiabatic character depends on the size of the supporting electrolyte cation.
A theoretical and experimental approach to the degree of adiabaticity of electrode processes is considered for the case where the electroactive species of the redox couple move freely in solution. Within a transition state-like framework, the adiabatic effect on the activation energy of electron transfer is included through the theory developed by Schmickler (W. Schmickler, J. Electroanal. Chem. 204 (1986) 31). The effect on the probability of electron tunnelling is also incorporated according to the Landau–Zener formalism (L. Landau, Phys. Z. Sowjetunion, 1932 29; C. Zener, Proc. R. Soc. London A 140 (1933) 660). In applying both aspects, it is recognised that the electron transfer takes place over a range of distances from the electrode surface.
The theory is applied to the study of the electroreduction kinetics of 2-nitropropane in fully-supported DMSO solutions on mercury hemispherical microelectrodes of 23μm radius. By fitting of experimental cyclic voltammetry, the standard rate constant (k0) is determined at different temperatures and for different supporting electrolytes. The reorganization energy and degree of adiabaticity from the variation of k0 with temperature are evaluated.
The application of differential pulse techniques (differential double pulse, differential multipulse, and differential normal pulse voltammetries) to the study of two-electron redox processes is ...carried out. The characterization of these requires the determination of the difference between the formal potentials of the electron transfer steps, which may reflect the interactions between the two different redox centers in the electroactive molecule. A new theory is developed for disk electrodes generating very simple analytical equations applicable to any electrode size and any double pulse technique. The influence of the technique parameters (pulse amplitude, pulse times) and the electrode geometry are examined. Procedures for the determination of the formal potentials are proposed from the values of the peak height and the half-peak width.
Background:
Blunt cerebrovascular injuries are rare injuries causing substantial morbidity and mortality. The appropriate screening methods and treatment options for these injuries are controversial. ...We examined our experience with these injuries at a community Level I Trauma center over a 51 month period.
Study Design:
A retrospective review and analysis was done of all patients with the diagnosis of a blunt cerebrovascular injury during this period.
Results:
Fourteen patients had blunt carotid injury (0.40%) and three had blunt vertebral injury (0.09%) out of 3,480 total blunt admissions. The overall incidence of blunt cerebrovascular injury was 0.49%. The most common associated injuries were to the head (59%) and chest (47%) regions. The overall mortality rate was 59% (10 of 17), with death occurring in 8 of 14 (57%) blunt carotid injury patients and 2 of 3 (67%) blunt vertebral injury patients. Eight of ten (80%) deaths were directly attributable to the blunt cerebrovascular injury. Median time until diagnosis was 12.5 h (range 1–336 h) for the entire group and 19.5 h for nonsurvivors. Diagnosis was delayed > 24 h in 7 patients and > 48 h in 5 patients. All five patients whose diagnoses were delayed > 48 h developed complications, and four (80%) of these patients died.
Conclusions:
Blunt cerebrovascular injury is uncommon, but lethal; particularly when the diagnosis is delayed. Aggressive screening protocols based on mechanism of injury, associated injuries, and physical findings are justified to minimize morbidity and mortality. Head and chest injuries may serve as markers for blunt cerebrovascular injury. Most deaths are directly attributable to the blunt cerebrovascular injury and not to associated injuries.
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