Are we overestimating the permanence of cellulose triacetate cinematographic films? A mathematical model for the vinegar syndrome

Among the earliest signs of degradation in cellulose triacetate cinematographic films is the generation of acetic acid due to hydrolytic deacetylation of the polymer, marked by an increase in the acidity of the films and emissions of acetic acid leading to a characteristic vinegar odour. We propose a mathematical model for predicting the onset of the vinegar syndrome which accounts for the autocatalytic effect of acetic acid on the deacetylation reaction. Model parameters are estimated from previously published experimental data from other research groups. These show free acidity changes in cellulose triacetate films subjected to accelerated ageing at temperatures of 70–100 °C. The model is validated against a different set of previously published experimental data of cellulose triacetate films aged at 21 °C and 35 °C, at 20, 35 and 50% relative humidity. The model demonstrates good quantitative agreement with the published experimental data. Predictions of film permanence at lower temperatures, similar to those present in the archives in which the films are typically stored, are made and compared with the predictions of film conservation guidelines. The results indicate that film permanence may be overestimated by existing guidelines, which do not account for autocatalysis in their modelling of the deacetylation rate. Our results suggest that cold storage, a common film conservation strategy, may be less effective at inhibiting degradation than previously thought. As cold storage typically requires film to be kept in confined spaces with limited air movement, conditions which promote autocatalysis, the inclusion of autocatalysis in our model is highly applicable to simulating this environment

Energy Consumption Forecasting Using Ensemble Learning Algorithms

DCAI 2019: Distributed Computing and Artificial Intelligence, 16th International Conference, Special SessionsThe increase of renewable energy sources of intermittent nature has brought several new challenges for power and energy systems. In order to deal with the variability from the generation side, there is the need to balance it by managing consumption appropriately. Forecasting energy consumption becomes, therefore, more relevant than ever. This paper presents and compares three different ensemble learning methods, namely random forests, gradient boosted regression trees and Adaboost. Hour-ahead electricity load forecasts are presented for the building N of GECAD at ISEP campus. The performance of the forecasting models is assessed, and results show that the Adaboost model is superior to the other considered models for the one-hour ahead forecasts. The results of this study compared to previous works indicates that ensemble learning methods are a viable choice for short-term load forecast.This work has received funding from National Funds through FCT (Fundaçao da Ciencia e Tecnologia) under the project SPET – 29165, call SAICT 2017.info:eu-repo/semantics/publishedVersio

The influence of perfusion solution on renal graft viability assessment

BACKGROUND: Kidneys from donors after cardiac or circulatory death are exposed to extended periods of both warm ischemia and intra-arterial cooling before organ recovery. Marshall’s hypertonic citrate (HOC) and Bretschneider’s histidine-tryptophan-ketoglutarate (HTK) preservation solutions are cheap, low viscosity preservation solutions used clinically for organ flushing. The aim of the present study was to evaluate the effects of these two solutions both on parameters used in clinical practice to assess organ viability prior to transplantation and histological evidence of ischemic injury after reperfusion. METHODS: Rodent kidneys were exposed to post-mortem warm ischemia, extended intra-arterial cooling (IAC) (up to 2 h) with preservation solution and reperfusion with either Krebs-Hensleit or whole blood in a transplant model. Control kidneys were either reperfused directly after retrieval or stored in 0.9% saline. Biochemical, immunological and histological parameters were assessed using glutathione-S-transferase (GST) enzymatic assays, polymerase chain reaction and mitochondrial electron microscopy respectively. Vascular function was assessed by supplementing the Krebs-Hensleit perfusion solution with phenylephrine to stimulate smooth muscle contraction followed by acetylcholine to trigger endothelial dependent relaxation. RESULTS: When compared with kidneys reperfused directly post mortem, 2 h of IAC significantly reduced smooth muscle contractile function, endothelial function and upregulated vascular cellular adhesion molecule type 1 (VCAM-1) independent of the preservation solution. However, GST release, vascular resistance, weight gain and histological mitochondrial injury were dependent on the preservation solution used. CONCLUSIONS: We conclude that initial machine perfusion viability tests, including ischemic vascular resistance and GST, are dependent on the perfusion solution used during in situ cooling. HTK-perfused kidneys will be heavier, have higher GST readings and yet reduced mitochondrial ischemic injury when compared with HOC-perfused kidneys. Clinicians should be aware of this when deciding which kidneys to transplant or discard

Improvement in photovoltaic performance of rutile-phased TiO2 nanorod/nanoflower-based dye-sensitized solar cell

An improved dye-sensitized solar cell (DSC) of rutile-phased titanium dioxide (TiO2) electrode with increased power conversion efficiency was successfully fabricated. Rutile-phased TiO2 nanorods and nanoflowers were grown directly on fluorine-doped SnO2 (FTO) by simple aqueous chemical growth technique using one-step hydrothermal process. The solution was prepared by mixing hydrochloric acid, deionized water, and titanium butoxide used as precursor. In the preparation of DSC, both TiO2 nanorods and nanoflowers, platinum (Pt), ruthenium dye N719, and DPMII electrolyte were used as photoelectrode, counter electrode, dye solution, and liquid electrolyte, respectively. The prepared rutile-phased TiO2 nanorods and nanoflowers samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The DSCs were fabricated based on the rutile-phased titanium dioxide nanorod and nanoflower photoelectrodes. For their energy conversion efficiency, I-V characteristics and electrochemical impedance spectroscopy were studied. We also investigated the effect of cetyltrimethylammonium bromide (CTAB) reaction times 2, 5, and 10 h in the preparation of rutile-phased TiO2 nanoflowers for DSC. CTAB is one of the capping agents that cover the refine surface of nanoparticles and prevent them from coagulation or aggregation. In our final result, the combination of rutile-phased TiO2 nanorod- and nanoflower-based DSCs showed best efficiency at approximately 3.11% due to its good electron transport of TiO2 nanorods and increased surface area by the TiO2 nanoflowers that had increased dye absorption

Factors affecting medical students in formulating their specialty preferences in Jordan

<p>Abstract</p> <p>Background</p> <p>In recent years there has been a growing appreciation of the issues of career preference in medicine as it may affect student learning and academic performance. However, no such studies have been undertaken in medical schools in Jordan. Therefore, we carried out this study to investigate the career preferences of medical students at Jordan University of Science and Technology and determine factors that might influence their career decisions.</p> <p>Methods</p> <p>A cross-sectional questionnaire-based survey was carried out among second, fourth and sixth year medical students at the Jordan University of Science and Technology, Irbid, Jordan during the academic year 2006/2007. A total of 440 students answered the questionnaire which covered demographic characteristics, specialty preferences, and the factors that influenced these career preferences. Possible influences were selected on the basis of a literature review and discussions with groups of medical students and physicians. Students were asked to consider 14 specialty options and select the most preferred career preference.</p> <p>Results</p> <p>The most preferred specialty expressed by male students was surgery, followed by internal medicine and orthopaedics, while the specialty most preferred by female students was obstetrics and gynaecology, followed by pediatrics and surgery. Students showed little interest in orthopedics, ophthalmology, and dermatology. While 3.1% of females expressed interest in anesthesiology, no male students did. Other specialties were less attractive to most students.</p> <p>Intellectual content of the specialty and the individual's competencies were the most influential on their preference of specialty. Other influential factors were the "reputation of the specialty", "anticipated income", and "focus on urgent care".</p> <p>Conclusion</p> <p>Surgery, internal medicine, pediatrics, and obstetrics and gynaecology were the most preferred specialty preferences of medical students at Jordan University of Science and Technology.</p

Response rates of standard interferon therapy in chronic HCV patients of Khyber Pakhtunkhwa (KPK)

<p>Abstract</p> <p>Background</p> <p>Interferon based therapy is used to eradicate the Hepatitis C Virus from the bodies of the infected individuals. HCV is highly prevalent in Khyber Pakhtunkhwa (KPK) that is why it is important to determine the response of standard interferon based therapy in Chronic HCV patients of the region.</p> <p>Study design</p> <p>A total of 174 patients were selected for interferon based therapy. The patients were selected from four different regions of KPK. After confirmation of active HCV infection by Real Time PCR, standard interferon with ribavirn was given to patients for 6 months. After completion of therapy, end of treatment virologic response (ETR) was calculated.</p> <p>Results</p> <p>Out of total 174 patients, 130 (74.71%) showed ETR and 44 (25.28%) did not show ETR. In district Bunir, out of 52 patients, 36 (69.23%) showed ETR and 16 (30.79%) did not show ETR. In district Mardan, out of the total 74 patients, 66 (89.18%) were negative for HCV RNA and 8 (10.81%) were resistant to therapy. In Peshawar, out of 22, 16 (60%) were negative and 6 (40%) were positive for HCV RNA at the end of 6 months therapy. In the Federally Administered Tribal Area (FATA), out of 18 only 10 (55.5%) were negative and 8 (44.45%) were positive for active HCV infection.</p> <p>Conclusion</p> <p>It is concluded that the response of antiviral therapy against HCV infection in chronic HCV patients of KPK province is 74.71%. The high response rate may be due to the prevalence of IFN-responsive HCV genotypes (2 and 3) in KPK.</p

Granulomatous cheilitis associated with exacerbations of Crohn's disease: a case report

<p>Abstract</p> <p>Introduction</p> <p>Crohn's disease is a disease involving the whole gastrointestinal tract from the mouth to the anus. Oral lesions are considered to be an important extraintestinal manifestation. Granulomatous cheilitis has been recognized as an early manifestation of Crohn's disease. It may follow, coincide with or precede the onset of Crohn's disease. The aim of this presentation is to describe a rare case of a patient with Crohn's disease in whom significant swelling of the lower lip not only preceded the diagnosis of Crohn's disease for two years, but it manifested as an early clinical index of the recurrence of the intestinal disease as well.</p> <p>Case presentation</p> <p>A man aged 25 was admitted in our department on August 1999 with chronic diarrhea and loss of weight. His bowel symptoms started in 1998 at the age of 24. However, two years previously (June 1996) he noticed a swelling of the lower lip, which contrasted significantly with the previously normal appearance of his mouth. A lip biopsy performed at that time was compatible with granulomatous cheilitis. Crohn's disease involving the terminal ileum and large bowel was diagnosed in 1998 and confirmed on the basis of colonoscopy, enteroclysis and histology findings of the small and large bowel. Conservative treatment resulted in clinical and laboratory improvement of the bowel symptoms and lip swelling. During the following years the disease was active with exacerbations and remissions of mild to moderate severity. The swelling of the lower lip occurred in parallel with the exacerbations of the bowel disease, returning to normal during periods of remission.</p> <p>Conclusion</p> <p>Significant swelling of the lower lip due to granulomatous cheilitis could be the first manifestation of Crohn's disease, preceding intestinal symptoms. Exacerbation of the lip lesion could be an early clinical sign of a relapse of the underlying intestinal disease.</p

Characterisation of the Immunophenotype of Dogs with Primary Immune-Mediated Haemolytic Anaemia

Immune-mediated haemolytic anaemia (IMHA) is reported to be the most common autoimmune disease of dogs, resulting in significant morbidity and mortality in affected animals. Haemolysis is caused by the action of autoantibodies, but the immunological changes that result in their production have not been elucidated.To investigate the frequency of regulatory T cells (Tregs) and other lymphocyte subsets and to measure serum concentrations of cytokines and peripheral blood mononuclear cell expression of cytokine genes in dogs with IMHA, healthy dogs and dogs with inflammatory diseases.19 dogs with primary IMHA, 22 dogs with inflammatory diseases and 32 healthy control dogs.Residual EDTA-anti-coagulated blood samples were stained with fluorophore-conjugated monoclonal antibodies and analysed by flow cytometry to identify Tregs and other lymphocyte subsets. Total RNA was also extracted from peripheral blood mononuclear cells to investigate cytokine gene expression, and concentrations of serum cytokines (interleukins 2, 6 10, CXCL-8 and tumour necrosis factor α) were measured using enhanced chemiluminescent assays. Principal component analysis was used to investigate latent variables that might explain variability in the entire dataset.There was no difference in the frequency or absolute numbers of Tregs among groups, nor in the proportions of other lymphocyte subsets. The concentrations of pro-inflammatory cytokines were greater in dogs with IMHA compared to healthy controls, but the concentration of IL-10 and the expression of cytokine genes did not differ between groups. Principal component analysis identified four components that explained the majority of the variability in the dataset, which seemed to correspond to different aspects of the immune response.The immunophenotype of dogs with IMHA differed from that of dogs with inflammatory diseases and from healthy control dogs; some of these changes could suggest abnormalities in peripheral tolerance that permit development of autoimmune disease. The frequency of Tregs did not differ between groups, suggesting that deficiency in the number of these cells is not responsible for development of IMHA

How does gender influence the recognition of cardiovascular risk and adherence to self-care recommendations? : a study in polish primary care

Background: Studies have shown a correlation between gender and an ability to change lifestyle to reduce the risk of disease. However, the results of these studies are ambiguous, especially where a healthy lifestyle is concerned. Additionally, health behaviors are strongly modified by culture and the environment. Psychological factors also substantially affect engagement with disease-related lifestyle interventions. This study aimed to examine whether there are differences between men and women in the frequency of health care behavior for the purpose of reducing cardiovascular risk (CVR), as well as cognitive appraisal of this type of risk. We also aimed to identify the psychological predictors of engaging in recommended behavior for reducing the risk of cardiovascular disease after providing information about this risk in men and women. Methods: A total of 134 consecutive eligible patients in a family practice entered a longitudinal study. At initial consultation, the individual’s CVR and associated health burden was examined, and preventive measures were recommended by the physician. Self-care behavior, cognitive appraisal of risk, and coping styles were then assessed using psychological questionnaires. Six months after the initial data collection, the frequency of subjects’ self-care behavior was examined. Results: We found an increase in health care behavior after providing information regarding the rate of CVR in both sexes; this increase was greater for women than for men. Women followed self-care guidelines more often than men, particularly for preventive measures and dietary advice. Women were more inclined to recognize their CVR as a challenge. Coping style, cognitive appraisal, age, level of health behaviors at baseline and CVR values accounted for 48% of the variance in adherence to self-care guidelines in women and it was 52% in men. In women, total risk of CVD values were most important, while in men, cognitive appraisal of harm/loss was most important. Conclusions: Different predictors of acquisition of health behavior are encountered in men and women. Our results suggest that gender-adjusted motivation models influencing the recognition process need to be considered to optimize compliance in patients with CVR