Excitation and relaxation in atom-cluster collisions

Electronic and vibrational degrees of freedom in atom-cluster collisions are treated simultaneously and self-consistently by combining time-dependent density functional theory with classical molecular dynamics. The gradual change of the excitation mechanisms (electronic and vibrational) as well as the related relaxation phenomena (phase transitions and fragmentation) are studied in a common framework as a function of the impact energy (eV...MeV). Cluster "transparency" characterized by practically undisturbed atom-cluster penetration is predicted to be an important reaction mechanism within a particular window of impact energies.Comment: RevTeX (4 pages, 4 figures included with epsf

Ileal Intussusception Caused by Vanek's Tumor: A Case Report

Inflammatory fibroid polyps (Vanek's tumor) are rare benign localized lesions originating in the submucosa of the gastrointestinal tract. Intussusceptions due to inflammatory fibroid polyps are uncommon; moreover, ileo-ileal intussusception with small bowel necrosis and perforation has rarely been reported. We report a 56-year-old woman who was admitted two days after complaints of nausea and vomiting. Abdominal examination revealed distension, signs of gastrointestinal perforation and clanging intestinal sounds. The patient underwent a emergency laparotomy which found a 17-cm invaginated mid-ileal segment with necrosis, perforation and fecal peritonitis. The ileal segment was resected and single-layer end-to-end anastomosis was performed. Histopathological analysis showed an ulcerative lesion with variable cellularity, formed by spindle cells with small number of mitosis and an abundant inflammatory infiltrate comprising mainly eosinophils. Immunohistochemistry confirmed the diagnosis of ileal Vanek's tumor. Although inflammatory fibroid polyps are seen very rarely in adults, they are among the probable diagnoses that should be considered in obstructive tumors of the small bowel causing intussusception with intestinal necrosis and perforation

Jejunal Diverticular Perforation due to Enterolith

Jejunal diverticulosis is a rare entity with variable clinical and anatomical presentations. Although there is no consensus on the management of asymptomatic jejunal diverticular disease, some complications are potentially life-threatening and require early surgical treatment. Small bowel perforation secondary to jejunal diverticulitis by enteroliths is rare. The aim of this study was to report a case of small intestinal perforation caused by a large jejunal enterolith. An 86-year-old woman was admitted with signs of diffuse peritonitis. After initial fluid recovery the patient underwent emergency laparotomy. The surgery showed that she had small bowel diverticular disease, mainly localized in the proximal jejunum. The peritonitis was due to intestinal perforation caused by an enterolith 12 cm in length, localized inside one of these diverticula. The intestinal segment containing the perforated diverticulum with the enterolith was removed and an end-to-end anastomosis was done to reconstruct the intestinal transit. The patient recovered well and was discharged from hospital on the 5th postoperative day. There were no signs of abdominal pain 1 year after the surgical procedure. Although jejunal diverticular disease with its complications, such as formation of enteroliths, is difficult to suspect in patients with peritonitis, it should be considered as a possible source of abdominal infection in the elderly patient when more common diagnoses have been excluded

Testing effectiveness of the revised Cape Town modified early warning and SBAR systems: a pilot pragmatic parallel group randomised controlled trial

Abstract Background Nurses’ recognition of clinical deterioration is crucial for patient survival. Evidence for the effectiveness of modified early warning scores (MEWS) is derived from large observation studies in developed countries. Methods We tested the effectiveness of the paper-based Cape Town (CT) MEWS vital signs observation chart and situation-background-assessment-recommendation (SBAR) communication guide. Outcomes were: proportion of appropriate responses to deterioration, differences in recording of clinical parameters and serious adverse events (SAEs) in intervention and control trial arms. Public teaching hospitals for adult patients in Cape Town were randomised to implementation of the CT MEWS/SBAR guide or usual care (observation chart without track-and-trigger information) for 31 days on general medical and surgical wards. Nurses in intervention wards received training, as they had no prior knowledge of early warning systems. Identification and reporting of patient deterioration in intervention and control wards were compared. In the intervention arm, 24 day-shift and 23 night-shift nurses received training. Clinical records were reviewed retrospectively at trial end. Only records of patients who had given signed consent were reviewed. Results We recruited two of six CT general hospitals. We consented 363 patients and analysed 292 (80.4%) patient records (n = 150, 51.4% intervention, n = 142, 48.6% control arm). Assistance was summoned for fewer patients with abnormal vital signs in the intervention arm (2/45, 4.4% versus (vs) 11/81, 13.6%, OR 0.29 (0.06–1.39)), particularly low systolic blood pressure. There was a significant difference in recording between trial arms for parameters listed on the MEWS chart but omitted from the standard observations chart: oxygen saturation, level of consciousness, pallor/cyanosis, pain, sweating, wound oozing, pedal pulses, glucose concentration, haemoglobin concentration, and “looks unwell”. SBAR was used twice. There was no statistically significant difference in SAEs (5/150, 3.3% vs 3/143, 2.1% P = 0.72, OR 1.61 (0.38–6.86)). Conclusions The revised CT MEWS observations chart improved recording of certain parameters, but did not improve nurses’ ability to identify early signs of clinical deterioration and to summon assistance. Recruitment of only two hospitals and exclusion of patients too ill to consent limits generalisation of results. Further work is needed on educational preparation for the CT MEWS/SBAR and its impact on nurses’ reporting behaviour. Trial registration Pan African Clinical Trials Registry, PACTR201406000838118. Registered on 2 June 2014, www.pactr.org

Structures and reactions of hydrated biomolecular cluster ions

Photo-induced reactions and metastable decompositions of cluster ions containing glycine, tryptophan, tryptophanylglicine and [Fe(III)-protoporphyrin]+ (hemin$^{+})$ ions solvated with water molecules are studied with electrospray ionization (ESI). The ESI ion source is improved to produce hydrated biomolecular cluster ions. Metastable decompositions of the hydrated clusters following primary mass selection are measured to determine the incremental solvent binding energies for the clusters by using evaporative ensemble model. From these experimental findings, stability of the cluster ions is discussed in terms of delocalization of ionic charges. We also measure the photodissociation yields of mass-selected water clusters containing hemin+ ions at 355 and 532 nm. The mass spectra of photofragments show the $\beta$-cleavage of carboxymethyl groups in addition to the evaporation of solvent molecules