Thermal analysis by DSC of Phase Change Materials, study of the damage effect

This paper deals with an experimental study of Phase Change Materials (PCMs) by DSC and focuses particularly on the influence of PCMs damage on their thermodynamic properties. First, different series of tests were performed on non-damaged PCMs (reference) using different masses and heating rates in order to optimize the choice of the experimental parameters used in DSC test. Accordingly, the specific heats at solid, liquid phases and the latent heats of PCMs were obtained. In addition, a fast approximate approach was suggested for the determination of the heat capacity of PCMs from a direct exploitation of the heat flux curves obtained by scanning PCMs at different heating rates. Finally, damaged PCMs were investigated and their thermal properties (specific heat and phase change enthalpy) were compared to the reference PCMs. It was shown from the obtained results that low heating rates are more suitable for PCMs scanning during DSC measurements in order to ensure a thermodynamic equilibrium within the sample. Furthermore, the results highlighted that damage of PCMs can lead to the loss of their specific heat capacity of about 28% compared to the non-damaged PCMs

Mutations in Eml1 lead to ectopic progenitors and neuronal heterotopia in mouse and human.

Neuronal migration disorders such as lissencephaly and subcortical band heterotopia are associated with epilepsy and intellectual disability. DCX, PAFAH1B1 and TUBA1A are mutated in these disorders; however, corresponding mouse mutants do not show heterotopic neurons in the neocortex. In contrast, spontaneously arisen HeCo mice display this phenotype, and our study revealed that misplaced apical progenitors contribute to heterotopia formation. While HeCo neurons migrated at the same speed as wild type, abnormally distributed dividing progenitors were found throughout the cortical wall from embryonic day 13. We identified Eml1, encoding a microtubule-associated protein, as the gene mutated in HeCo mice. Full-length transcripts were lacking as a result of a retrotransposon insertion in an intron. Eml1 knockdown mimicked the HeCo progenitor phenotype and reexpression rescued it. We further found EML1 to be mutated in ribbon-like heterotopia in humans. Our data link abnormal spindle orientations, ectopic progenitors and severe heterotopia in mouse and human

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Management of an infected aortic graft with endovascular stent grafting

Aortic graft infection, one of the most common fatal complications of aortovascular surgery, is managed mainly by the removal of infected graft material and re-establishment of vascular continuity using an extra-anatomical bypass or in situ graft replacement. Despite significant progress in perioperative, surgical, and medical treatments, the mortality and morbidity for this condition remain high. Here, we report the use of endograft implantation and prolonged intravenous antibiotics to successfully treat a life-threatening Dacron aortic tube graft infection and anastomotic leak. Although the gold standard is surgical removal of infected material and repair with a homograft, in certain extremely high-risk patients such as ours, an alternate strategy may be warranted when the risks associated with surgery are prohibitive. Endovascular repair of a surgical Dacron graft leak may provide a novel temporizing measure in the acute setting, allowing for delayed semi-urgent surgical intervention, or it may provide a definitive treatment, as in our case. At the four-year follow-up, our patient was well with a good quality of life and with no clinical, radiological, or biochemical evidence of infection

Intramural collection caused by contrast extravasation into the ascending aortic wall

Cardiac catheterization is a procedure routinely performed worldwide, with an estimated amount of 61 000 coronary angioplasties performed in the UK annually. Associated mortality—in the region of 0.1–0.2%—is minimal and complication rate approximately 1.5%. The most serious complications described are embolic stroke, cardiac chamber perforation, aortic dissection, coronary occlusions or dissection, and major peripheral vascular complications, including retroperitoneal haematoma and life-threatening haemorrhage. We report the case of a 75-year old patient who had inadvertent contrast agent injection into the aortic wall, leading to a localized contrast collection within the tunica media. This complication has been described before but only in association with coronary artery dissection. It is important to diagnose and manage such a situation, as most iodinated intravascular contrast agents exert a high osmotic load and thereby lead to tissue oedema and necrosis on extravasation. We describe the management of the case and discuss relevant therapeutic strategies

Central Nervous System (CNS) Delivery of Glucocorticoids Is Fine-Tuned by Saturable Transporters at the Blood-CNS Barriers and Nonbarrier Regions

Proper functioning of the hypothalamic-pituitary-adrenal axis depends on the ability of glucocorticoids (GCs), mainly cortisol in humans and corticosterone in rodents, to access brain targets and regulate their own secretion. Being highly lipophilic, GCs have been assumed to passively diffuse through the cell membrane. However, the access of these GCs to the brain may be a more complicated process, because the free movement of molecules into the central nervous system (CNS) is restricted by the presence of the blood-brain and blood-cerebrospinal fluid barriers. GCs do interact with some transporter systems, including the efflux transporter, P-glycoprotein, and members of the organic anion transporter polypeptide (oatp) family, both of which have been found at the blood-CNS barriers. Using an in situ brain/choroid plexus perfusion, P-glycoprotein was shown to not majorly regulate the access of [(3)H]cortisol and [(3)H]corticosterone to the choroid plexus or pituitary gland. Interactions of [(3)H]cortisol and [(3)H]corticosterone with saturable influx transporters were detected at the hypothalamus, cerebellum, choroid plexus, and pituitary gland. Oatp2 seems to have some role in the influx of [(3)H]cortisol and [(3)H]corticosterone to the choroid plexus and the pituitary gland and other transporters, unlikely to be oatp2, may play a very minor role in the access of [(3)H]cortisol and [(3)H]corticosterone to the brain, as well as having a significant effect on [(3)H]glucocorticoid receptor accumulation in the pituitary gland. Overall, these data suggest that the majority of cortisol and corticosterone present in the plasma diffuse into the CNS and that transporters do not play a major role in the accumulation of these GCs in the brain