Impact of overall and particle surface heat transfer coefficients on thermal process optimization in rotary retorts

This study attempts to examine the significance of recent research that has focused on efforts to estimate values for global and surface heat transfer coefficients under forced convection heating induced by end-over-end rotation in retorting of canned peas in brine. The study confirms the accuracy of regression analysis used to predict values for heat transfer coefficients as a function of rotating speed and headspace, and uses them to predict values over a range of process conditions, which make up the search domain for process optimization. These coefficients were used in a convective heat transfer model to establish a range of lethality-equivalent retort temperature-time processes for various conditions of retort temperature, rotating speed, and headspace. Then, they were coupled with quality factor kinetics to predict the final volume average and surface quality retention resulting from each process and to find the optimal thermal process conditions for canned fresh green peas. Results showed that maximum quality retention (surface and volume average retention) was achieved with the shortest possible process time (made possible with highest retort temperature), and reached the similar level in all cases with small difference between surface and volume average quality retention. The highest heat transfer coefficients (associated with maximum rotating speed and headspace) showed a 10% reduction in process time over that required with minimum rotating speed and headspace. The study concludes with a discussion of the significance of these findings and degree to which they were expected.

Cognitive declines following bilateral subthalamic nucleus deep brain stimulation for the treatment of Parkinson's disease

BACKGROUND

We investigated the cognitive and psychiatric outcome 6 months after bilateral subthalamic nucleus deep brain stimulation (DBS) for the treatment of Parkinson's disease (PD) using a disease control group.

METHODS

23 patients who underwent DBS were compared with 28 medically treated patients with PD at baseline and at 6 months for neuropsychological measures. In addition to the group outcomes, we report reliable change indices (RCI) and a dementia caseness analysis.

RESULTS

Patients who underwent DBS demonstrated a significant decline in verbal memory compared with the control group (p<0.003), and trends for decline on oral information processing, including verbal fluency, timed transcription and word naming. Patients who underwent DBS demonstrated declines in attention, set shifting and semantic fluency but these changes were similar to the rate of decline in the PD group. RCI indicated that patients who underwent DBS demonstrated clinically significant declines in verbal fluency (p<0.01) and inhibition of a dominant response (p<0.003), with trends for declines in set shifting (p<0.02) and verbal long term recall (p<0.08), indicative of frontostriatal dysfunction. Patients who underwent DBS did not demonstrate significant changes in depression, anxiety or psychological distress scores. The caseness analysis revealed that one of the patients who underwent DBS (4%) converted to dementia over 6 months compared with none of the PD controls.

CONCLUSIONS

Our findings demonstrated that patients who underwent DBS experienced declines in verbal recall and trends for declines in oral information processing 6 months following surgery, even when good motor outcome was achieved. Potential candidates should be counselled about the risk of mild frontostriatal cognitive declines following DBS to weigh the risks and benefits of surgery.

The relationship of retinal vascular calibre to diabetes and retinopathy: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study

AIMS/HYPOTHESIS

The aim of the study was to examine the relationship of retinal vascular calibre with glucose intolerance, diabetes and retinopathy in a population-based cohort.

METHODS

The Australian Diabetes, Obesity and Lifestyle study recruited adults aged > or =25 years old from across Australia. Participants were classified using an oral glucose tolerance test as having normal glucose tolerance (NGT), impaired glucose tolerance (IGT), impaired fasting glucose (IFG), known diabetes or newly diagnosed diabetes. Digital retinal photographs were taken of all participants with diabetes, IGT and IFG, and a sample of those with NGT, and graded for the presence of retinopathy. Retinal vascular calibre was measured from photographs by a computer-assisted method.

RESULTS

Of the 1,998 participants with gradable retinal images, 16% had known diabetes, 17% newly diagnosed diabetes, 42% IGT, 6% IFG and 19% NGT. After multivariable adjustment, retinal arteriolar calibre was significantly larger in people with known diabetes (178.9 microm) compared with participants with NGT (174.6 microm, p = 0.02), IGT/IFG (175.5 microm, p = 0.02) or newly diagnosed diabetes (175.6 microm, p = 0.047). One SD increase in mean arteriolar calibre was associated with higher odds of diabetes compared with NGT (odds ratio [OR] = 1.28, 95%CI = 1.06-1.55). After multivariable adjustment, each SD increase in venular calibre was associated with higher odds of having retinopathy in persons with IGT/IFG (OR = 1.78, 95%CI = 1.36-2.34) or in persons with diabetes (OR = 1.68, 95%CI = 1.23-2.29).

CONCLUSIONS/INTERPRETATION

Diabetes is associated with larger retinal arteriolar calibre and retinopathy with larger retinal venular calibre. The contrasting associations may reflect different underlying pathophysiological processes in the natural history of diabetes.

The effects of AZD3582 [4-(nitroxy)butyl-(2S)-2-(6-methoxy-2-naphthyl) propanoate], and naproxen on key pathogenic steps in NSAID-enteropathy in the rat

BACKGROUND

The pathogenesis of NSAID-induced enteropathy may involve dual inhibition of the cyclooxygenase (1 and 2) and a topical effect with sequential increased intestinal permeability, development of inflammation and ulcers. It has been suggested that nitric-oxide donating drugs cause significantly less gastrointestinal injury by counteracting for NSAID-induced reductions in blood flow.

AIMS

To compare the effects of AZD3582 [4-(nitroxy)butyl-(2S)-2-(6-methoxy-2-naphthyl) propanoate], and naproxen on key pathogenic steps in NSAID-enteropathy in the rat.

METHODS

Single doses of AZD3582, naproxen (dose range 10-300 micromol/kg) or vehicle were given to male Sprague Dawley rats. Intestinal permeability (51CrEDTA) and intestinal inflammation (granulocyte marker protein) was quantitated and ulcer counts made.

RESULTS

Intestinal permeability (all doses) and inflammation (highest dose of the drugs) increased significantly from control levels following naproxen and AZD3582 and there was no significant difference between the drugs. Median ulcer counts were, however, significantly (p < 0.01) lower with AZD3582 (4 +/- 2) than with naproxen (17 +/- 4).

CONCLUSIONS

Naproxen and AZD3582 are equally associated with increased small intestinal permeability and inflammation, which is the consequence of their topical effect. The reduced small bowel ulcer counts with AZD3582 accords with the suggestion that vascular factors are the main driving force for NSAID-induced ulcer formation.

Structured surveillance of infantile gastroenteritis in East Anglia, UK: incidence of infection with common viral gastroenteric pathogens

The aim of this study was to investigate the burden of disease associated with gastroenteric viruses (rotavirus, norovirus, sapovirus, astrovirus and enteric adenovirus) using structured surveillance of children aged <6 years in the community. Faecal samples were collected between 2000 and 2003 from 685 children with symptoms of gastroenteritis. The children comprised three groups; 223 in the structured surveillance cohort, 203 in a community cohort and 259 in a cohort of hospitalized children. All samples were tested for the presence of viral pathogens using molecular methods. Questionnaires were sent to the parents/carers of the children recruited to the structured surveillance cohort in order to collect data that would allow an estimation of the severity of illness by means of the Vesikari score, and of the cost associated with gastrointestinal disease in this age group. A viral aetiological agent was detected in 53.5% of samples tested. Rotavirus was the most common pathogen found in all three cohorts followed by norovirus and enteric adenoviruses. Multiple viruses were found in 8% of the samples, and commonly involved rotavirus and any other virus. G1P[8] was the most commonly detected rotavirus strain and there was no significant difference in the distribution of rotavirus genotypes among the three cohorts. Analysis of the questionnaires indicated that rotavirus infections were likely to be more severe than any other virus infection, and children from whom a viral pathogen was identified were more likely to require rehydration therapy.