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H Shift (h + shift)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Rearrangements in Model Peptide-Type Radicals via Intramolecular Hydrogen-Atom Transfer

HELVETICA CHIMICA ACTA, Issue 10 2006
Damian Moran
Abstract Intramolecular H-atom transfer in model peptide-type radicals was investigated with high-level quantum-chemistry calculations. Examination of 1,2-, 1,3-, 1,5-, and 1,6[C,,,N]-H shifts, 1,4- and 1,7[C,,,C]-H shifts, and 1,4[N,,,N]-H shifts (Scheme,1), was carried out with a number of theoretical methods. In the first place, the performance of UB3-LYP (with the 6-31G(d), 6-31G(2df,p), and 6-311+G(d,p) basis sets) and UMP2 (with the 6-31G(d) basis set) was assessed for the determination of radical geometries. We found that there is only a small basis-set dependence for the UB3-LYP structures, and geometries optimized with UB3-LYP/6-31G(d) are generally sufficient for use in conjunction with high-level composite methods in the determination of improved H-transfer thermochemistry. Methods assessed in this regard include the high-level composite methods, G3(MP2)-RAD, CBS-QB3, and G3//B3-LYP, as well as the density-functional methods B3-LYP, MPWB1K, and BMK in association with the 6-31+G(d,p) and 6-311++G(3df,3pd) basis sets. The high-level methods give results that are close to one another, while the recently developed functionals MPWB1K and BMK provide cost-effective alternatives. For the systems considered, the transformation of an N-centered radical to a C-centered radical is always exothermic (by 25,kJ,,,mol,1 or more), and this can lead to quite modest barrier heights of less than 60,kJ,,,mol,1 (specifically for 1,5[C,,,N]-H and 1,6[C,,,N]-H shifts). H-Migration barriers appear to decrease as the ring size in the transition structure (TS) increases, with a lowering of the barrier being found, for example when moving from a rearrangement proceeding via a four-membered-ring TS (e.g., the 1,3[C,,,N]-H shift, CH3C(O)NH.,,,.CH2C(O)NH2) to a rearrangement proceeding via a six-membered-ring TS (e.g., the 1,5[C,,,N]-H shift, .NHCH2C(O)NHCH3,,,NH2CH2C(O)NHCH2.). [source]

Improved pain management in pediatric postoperative liver transplant patients using parental education and non-pharmacologic interventions

PEDIATRIC TRANSPLANTATION, Issue 2 2006
Paul J. Sharek
Abstract:, A pain management intervention, consisting of pretransplant parental education and support, pre- and postoperative behavioral pediatrics consultation, postoperative physical and occupational therapy consultation, and implementation of non-pharmacologic pain management strategies, was introduced to all pediatrics patients receiving liver transplants at Lucile Packard Children's Hospital beginning August 2001. Children receiving transplants pre-intervention (May, 2000 to February, 2001) and post-intervention (August, 2001 to March, 2002) were compared using pain scores, parent perception of pain ratings, length of stay, ventilator days, total cost, and opioid use. A total of 27 children were evaluated (13 historical control, 14 intervention). The two populations did not differ on age at transplant (mean age 53.8 vs. 63.6 months), sex (46.1% vs. 50% male), ethnicity (53.8% vs. 57.1% white, non-Hispanic) weight at transplant (17.5 vs. 24.7 kg), percent with biliary atresia as the primary reason for transplant (42.9% vs. 69.2%), percent with status 1 transplant listing score (38.5% vs. 50.0%), or public insurance status (30.8 vs. 57.2% with Medicaid). No differences were found in mean pediatric intensive care unit (PICU) postoperative length of stay (6.7 vs. 5.3 days), total postoperative length of stay (17.5 vs. 17.5 days), total inpatient length of stay (27.0 vs. 24.4 days), time to extubation (30 vs. 24.3 h), total cost ($147 983 vs. $157 882) or opioid use through postoperative day (POD) 6 (0.24 vs. 0.25 mg/kg/day morphine equivalent). A decrease in mean pain score between POD 0 and 6 (2.82 vs. 2.12; p = 0.047), a decrease in mean parental pain perception score (3.1 vs. 2.1; p = 0.001), and an increase in number of pain assessments per 12 h shift (3.43 vs. 6.79; p < 0.005) were seen. A comprehensive non-pharmacologic postoperative pain management program in children receiving a liver transplant was associated with decreased pain scores, improved parent perception of pain, and an increased number of pain assessments per 12 h shift. No increases in lengths of stay (PICU, postoperative, total), time to extubation, or total cost were found. [source]

Twelve-hour shift on ITU: a nursing evaluation

NURSING IN CRITICAL CARE, Issue 3 2003
Annette Richardson
Summary ,This paper describes the introduction and subsequent evaluation of a 12-h shift system in a large ITU in the northeast of UK ,To date, only a small number of studies has evaluated nurses working the 12-h shifts in critical care areas ,To evaluate the level of staff satisfaction, data were collected by means of a questionnaire involving 41 nurses, at 3 months following the introduction of the 12-h shifts ,The responses from the evaluation advocated the continuation of 12-h shifts with alternative shift patterns for nurses who felt dissatisfied with the current system ,Twelve-hour shifts can be seen as a flexible system for nurses working in intensive care and may assist with staff satisfaction and improving nurse recruitment and retention [source]