A Numerical Thermal-Hydraulic Model to Simulate the Fast Transients in a Supercritical Water Channel Subjected to Sharp Pressure Variations

The present work demonstrates the extension of a thermal-hydraulic model, THRUST, with an objective to simulate the fast transient flow dynamics in a supercritical water channel of circular cross section. THRUST is a 1-D model which solves the nonlinearly coupled mass, axial momentum and energy conservation equations in time domain based on a characteristics-dependent fully implicit finite difference scheme using an Eulerian approach. The model developed accounts for the compressibility of the supercritical flow by considering the finite value of acoustic speed in the solution algorithm and treats the boundary conditions naturally. A supercritical water channel of circular cross section, for which the experimental data is available at steady state operating conditions, is chosen for the transient simulations to start with. Two different case studies are undertaken with a purpose to assess the capability of the model to analyze the fast transient processes caused by the large reduction in system pressure. The first transient case study is where the initial exit pressure is reduced by 1 MPa exponentially in a time span of 5 s. In the second case study, the transient is initiated with a sudden step decrease in the exit pressure by the same amount. Results obtained for both the case studies show the desired performance from the model developed.     

Extrinsic compression of left main coronary artery due to dilated pulmonary trunk resulting in ischaemic symptoms

Left coronary artery compression syndrome is an uncommon entity and characterized by compression of the LMCA in-between the aorta and an enlarged main pulmonary arterial trunk. It is usually associated with a congenital cardiac defect. Cardiac 64-slice MDCT provides a non-invasive and an accurate method for assessing the degree of dynamic LMCA compression throughout the cardiac cycle, its angulation relative to the left sinus of Valsalva and depiction of pulmonary pathology, making it a valuable tool in the workup of patients suspected of left coronary artery compression.     

Association Between Parenting Stress and Functional Impairment Among Children Diagnosed with Neurodevelopmental Disorders

The objective of this study was to examine the association between parenting stress and functional impairment among children with Neurodevelopmental Disorder (NDD). A sample of 150 parents of children diagnosed with NDD were recruited from schools that offer special education services. Parents completed a self-administered survey containing the parenting stress index-short form (PSI-SF) scale and the Columbia Impairment Scale. The multiple logistic regression conducted to compare those with clinically significant PSI-SF scores indicated that the risk of parents with clinically significant scores of parenting stress increased 5.5 times with functionally impaired children with NDD. Further the risk of stress increased 4.6 times when these parents reported having their own disorder/disease. The risk of stress was reduced by 57% for those who had higher than a college level education compared to those with a college level education or below. These findings might help health care providers to initiate early intervention strategies such as peer support and education that can prevent parenting stress and reduce the risk of potential incidence of depression.     

Acetylation of MEK2 and I kappa B kinase (IKK) activation loop residues by YopJ inhibits signaling

To overcome host defenses, bacterial pathogens of the genus Yersinia inject specific effector proteins into colonized mammalian cells. One such virulence factor, YopJ, inhibits the host inflammatory response and induces apoptosis of immune cells by blocking multiple signaling pathways, including the MAPK and NF-kappaB pathways. In this study, we show that YopJ exerts its deleterious effects by catalyzing the acetylation of two serine residues in the activation loop of the MAP kinase kinase, MEK2. This covalent modification prevents the phosphorylation of these serine residues that is required for activation of MEK2 and downstream signal propagation. We also show that YopJ causes acetylation of a threonine residue in the activation loop of both the alpha and beta subunits of the NF-kappaB pathway kinase, IKK. These results establish a hitherto uncharacterized mode of action for bacterial toxins and suggest the possibility that serine/threonine acetylation may occur even under nonpathogenic conditions and may be a widespread protein modification regulating protein function in eukaryotic cells.     

Upper gastrointestinal bleeding in neck of femur fracture patients: a single tertiary centre experience

This study aimed to identify the incidence of perioperative acute upper gastrointestinal bleeding (UGIB) in our hip fracture patients; to evaluate the characteristics, management and clinical outcomes of these patients; and to explore risk factors and protective factors. Of the 1691 consecutive patients admitted for surgical management of hip fractures, 11 (0.65%) had UGIB and a further four patients for each case were selected as controls for evaluation of risk factors and protective factors. Pre‐existing peptic ulcer disease was identified as a risk factor for acute UGIB (odds ratio 7.9; 95% confidence interval: 1.1–54.9). This study reported a very low incidence of UGIB in hip fracture patients. Despite being a high‐risk population, timely endoscopic evaluation can be safely undertaken to optimise patient outcome. When risk factors such as history of peptic ulcer disease are present, additional precaution including gastro‐protective agent and nutritional support should be undertaken.