Monte Carlo studies of the square Ising model with next-nearest-neighbor interactions

We apply a new entropic scheme to study the critical behavior of the square-lattice Ising model with nearest- and next-nearest-neighbor antiferromagnetic interactions. Estimates of the present scheme are compared with those of the Metropolis algorithm. We consider interactions in the range where superantiferromagnetic (SAF) order appears at low temperatures. A recent prediction of a first-order transition along a certain range (0.5-1.2) of the interaction ratio $(R=J_{nnn}/J_{nn})$ is examined by generating accurate data for large lattices at a particular value of the ratio $(R=1)$. Our study does not support a first-order transition and a convincing finite-size scaling analysis of the model is presented, yielding accurate estimates for all critical exponents for R=1 . The magnetic exponents are found to obey ``weak universality'' in accordance with a previous conjecture.Comment: 9 pages, 7 figures, Proceedings of the third NEXT Sigma Phi International Conference, kolymbari, Greece (2005

Combustion and emissions characteristics of date pit methyl ester in a single cylinder direct injection diesel engine

Current biofuels for diesel engines are largely derived from food crops and there is significant concern, recognised by legislation, that such fuels do not result in net reductions of greenhouse gas emissions when considering the entirety of the production to usage lifecycle. A potential alternative approach is to utilise the lipid content of organic waste streams arising from food crop cultivation for the manufacture of sustainable diesel fuels. This paper therefore presents experimental studies carried out on a modern direct injection diesel engine supplied with a biodiesel (fatty acid methyl esters) produced from waste date pits to determine the combustion and emissions characteristics of an alternative fuel produced from a food residue. Date pit methyl esters were tested relative to both rapeseed and soybean methyl esters, unblended and as blends with a reference fossil diesel, alongside reference fossil diesel and a commercially available fossil diesel from Oman, at constant injection timing and constant ignition timing at a constant engine speed of 1200 rpm. Gas chromatograph analysis of the methyl esters fatty acid composition found a significantly shorter mean alkyl moiety chain length and lower number of double bonds in the case of the date pit esters than either the rapeseed or soybean biodiesel. All of the methyl esters exhibited a similar duration of ignition delay less than that displayed by a reference fossil diesel, but with a higher premixed burn fraction and peak heat release rate in the case of date pit methyl esters relative to those of rapeseed and soybean. Exhaust emissions of NOx were found to be lowest for the unblended date pit methyl esters, suggesting a greater influence of adiabatic flame temperature on rates of thermal NOx production than global in-cylinder temperatures in the case of the unblended methyl esters. Relative to the reference fossil diesel and Oman diesel, all of the methyl esters tested resulted in low particulate matter emissions

Liver secretin receptor predicts portoenterostomy outcomes and liver injury in biliary atresia

Biliary atresia (BA) is a chronic neonatal cholangiopathy characterized by fibroinflammatory bile duct damage. Reliable biomarkers for predicting native liver survival (NLS) following portoenterostomy (PE) surgery are lacking. Herein we explore the utility of 22 preidentified profibrotic molecules closely connected to ductular reaction (DR) and prevailing after successful PE (SPE), in predicting PE outcomes and liver injury. We used qPCR and immunohistochemistry in a BA cohort including liver samples obtained at PE (n = 53) and during postoperative follow-up after SPE (n = 25). Of the 13 genes over-expressed in relation to cholestatic age-matched controls at PE, only secretin receptor (SCTR) expression predicted cumulative 5-year NLS and clearance of jaundice. Patients in the highest SCTR expression tertile showed 34–55% lower NLS than other groups at 1–5 years after PE (P = 0.006–0.04 for each year). SCTR expression was also significantly lower [42 (24–63) vs 75 (39–107) fold, P = 0.015] among those who normalized their serum bilirubin after PE. Liver SCTR expression localized in cholangiocytes and correlated positively with liver fibrosis, DR, and transcriptional markers of fibrosis (ACTA2) and cholangiocytes (KRT7, KRT19) both at PE and after SPE. SCTR is a promising prognostic marker for PE outcomes and associates with liver injury in BA

Monte Carlo studies of the square Ising model with next-nearest-neighbor interactions

We apply a new entropic scheme to study the critical behavior of the square-lattice Ising model with nearest- and next-nearest-neighbor antiferromagnetic interactions. Estimates of the present scheme are compared with those of the Metropolis algorithm. We consider interactions in the range where superantiferromagnetic (SAF) order appears at low temperatures. A recent prediction of a first-order transition along a certain range (0.5-1.2) of the interaction ratio (R=Jnnn/Jnn) is examined by generating accurate data for large lattices at a particular value of the ratio (R=1). Our study does not support a first-order transition and a convincing finite-size scaling analysis of the model is presented, yielding accurate estimates for all critical exponents for R=1. The magnetic exponents are found to obey "weak universality" in accordance with a previous conjecture

Congenital vascular anomalies of the liver

Congenital vascular anomalies of the liver include a range of malformations of the portal venous, hepatic arterial and venous systems. Congenital portosystemic shunts and arteriovenous malformations make up the two most frequent such malformations. While infantile haemangiomas of the liver, endothelial tumours characterised by vascular proliferation should also be considered, as a proportion of them form prenatally. Evidence to support treatment strategies for these infants and children has been mainly based on small case series. In this review, we explore classification, clinical presentation, investigation and treatment strategie

Portal Venous Deprivation in Patients with Portosystemic Shunts and Its Effect on Liver Tumors

To outline the use of radiological investigations in patients with congenital portosystemic shunts (CPS) and to assess the degree of portal venous deprivation in relation to the development of liver tumors

Preservation of micro-architecture and angiogenic potential in a pulmonary acellular matrix obtained using intermittent intra-tracheal flow of detergent enzymatic treatment

Tissue engineering of autologous lung tissue aims to become a therapeutic alternative to transplantation. Efforts published so far in creating scaffolds have used harsh decellularization techniques that damage the extracellular matrix (ECM), deplete its components and take up to 5 weeks to perform. The aim of this study was to create a lung natural acellular scaffold using a method that will reduce the time of production and better preserve scaffold architecture and ECM components. Decellularization of rat lungs via the intratracheal route removed most of the nuclear material when compared to the other entry points. An intermittent inflation approach that mimics lung respiration yielded an acellular scaffold in a shorter time with an improved preservation of pulmonary micro-architecture. Electron microscopy demonstrated the maintenance of an intact alveolar network, with no evidence of collapse or tearing. Pulsatile dye injection via the vasculature indicated an intact capillary network in the scaffold. Morphometry analysis demonstrated a significant increase in alveolar fractional volume, with alveolar size analysis confirming that alveolar dimensions were maintained. Biomechanical testing of the scaffolds indicated an increase in resistance and elastance when compared to fresh lungs. Staining and quantification for ECM components showed a presence of collagen, elastin, GAG and laminin. The intratracheal intermittent decellularization methodology could be translated to sheep lungs, demonstrating a preservation of ECM components, alveolar and vascular architecture. Decellularization treatment and methodology preserves lung architecture and ECM whilst reducing the production time to 3 h. Cell seeding and in vivo experiments are necessary to proceed towards clinical translation

The Blunt Liver and Spleen Trauma (BLAST) audit: national survey and prospective audit of children with blunt liver and spleen trauma in major trauma centres

Abstract Purpose To compare the reported and observed management of UK children with blunt liver or spleen injury (BLSI) to the American Pediatric Surgical Association (APSA) 2019 BLSI guidance. Methods UK Paediatric Major Trauma Centres (pMTCs) undertook 1 year of prospective data collection on children admitted to or discussed with those centres with BLSI and an online questionnaire was distributed to all consultants who care for children with BLSI in those centres. Results All 21/21 (100%) pMTCs participated; 131 patients were included and 100/152 (65%) consultants responded to the survey. ICU care was reported and observed to be primarily determined using haemodynamic status or concomitant injuries rather than injury grade, in accordance with APSA guidance. Bed rest was reported to be determined by grade of injury by 63% of survey respondents and observed in a similar proportion of patients. Contrary to APSA guidance, follow-up radiological assessment of the injured spleen or liver was undertaken in 44% of patients before discharge and 32% after discharge, the majority of whom were asymptomatic. Conclusions UK management of BLSI differs from many aspects of APSA guidance. A shift towards using clinical features to determine ICU admission and readiness for discharge is demonstrated, in line with a strong evidence base. However, routine bed rest and re-imaging after BLSI is common, contrary to APSA guidance. This disparity may exist due to concern that evidence around the incidence, presentation and natural history of complications after conservatively managed BLSI, particularly bleeding from pseudoaneurysms, is weak. </jats:sec