Simulation of the response of a silicon pixel detector

A model to simulate the response of a silicon pixel detector is described. The effects of geometrical charge sharing, electronic noise threshold dispersion, capacitive coupling between pixel channels and d -rays production have been taken into account. The model has been tested on the Omega3chip, which is the direct predecessor of the ALICE pixel detector, to be used in the inner tracking system of the ALICE experiment. The model is able to reproduce the experimental data and the resulting parameters are consistent with the measurements made on the Omega3chip. Key words:silicon pixel, simulation PACS:07.05.T,29.40.

Terminal spreading depolarization and electrical silence in death of human cerebral cortex

Objective: Restoring the circulation is the primary goal in emergency treatment of cerebral ischemia. However, better understanding of how the brain responds to energy depletion could help predict the time available for resuscitation until irreversible damage and advance development of interventions that prolong this span. Experimentally, injury to central neurons begins only with anoxic depolarization. This potentially reversible, spreading wave typically starts 2 to 5 minutes after the onset of severe ischemia, marking the onset of a toxic intraneuronal change that eventually results in irreversible injury. Methods: To investigate this in the human brain, we performed recordings with either subdural electrode strips (n = 4) or intraparenchymal electrode arrays (n = 5) in patients with devastating brain injury that resulted in activation of a Do Not Resuscitate–Comfort Care order followed by terminal extubation. Results: Withdrawal of life‐sustaining therapies produced a decline in brain tissue partial pressure of oxygen (ptiO2) and circulatory arrest. Silencing of spontaneous electrical activity developed simultaneously across regional electrode arrays in 8 patients. This silencing, termed “nonspreading depression,” developed during the steep falling phase of ptiO2 (intraparenchymal sensor, n = 6) at 11 (interquartile range [IQR] = 7–14) mmHg. Terminal spreading depolarizations started to propagate between electrodes 3.9 (IQR = 2.6–6.3) minutes after onset of the final drop in perfusion and 13 to 266 seconds after nonspreading depression. In 1 patient, terminal spreading depolarization induced the initial electrocerebral silence in a spreading depression pattern; circulatory arrest developed thereafter. Interpretation: These results provide fundamental insight into the neurobiology of dying and have important implications for survivable cerebral ischemic insults. Ann Neurol 2018;83:295–31

The inflammatory microenvironment in colorectal neoplasia

Peer reviewedPublisher PD

Evaluation of a psychoeducational intervention for adolescents with inflammatory bowel disease

OBJECTIVES: Inflammatory bowel disease (IBD), comprising Crohn's disease, ulcerative colitis, and indeterminate colitis, often has its onset in adolescence. The aim of this study was to evaluate whether a psychoeducational group intervention (aiming to enhance information seeking and giving about the disease, relaxation, social competence, and positive thinking) can strengthen the coping efforts of adolescents with IBD and have a positive effect on their Health-Related Quality of Life (HRQoL). METHODS: Adolescent IBD patients from the Emma Children's Hospital AMC and adolescent members of the Crohn and Ulcerative Colitis Association in The Netherlands, were invited to participate in The intervention study. Using reliable and valid self-report instruments the adolescent's coping styles, feelings of competence, and HRQoL were assessed before and 6-8 months after the intervention. The parents were asked to fill in the Child Behavior Check List. Linear regression analyses were performed to test whether group participation was predictive of the outcome measures while correcting for the first measurement occasion and sex. RESULTS AND CONCLUSION: Forty patients responded positively to invitation to the intervention. Eighteen adolescents, however, lived too far away to attend and served as a control group. Twenty-two children were enrolled and attended in groups of four to six children in six group sessions, supervised by two psychologists. The intervention seemed to have a positive effect on: coping (predictive control, P<0.01), feelings of competence (global self-worth, P<0.05 and physical appearance, P<0.01), and HRQoL (body image, P<0.05). These results give good reason to continue this intervention study with a larger population. © 2009 Lippincott Williams & Wilkins, Inc