Microstructural diversity, nucleation paths and phase behaviour in binary mixtures of charged colloidal spheres

We study low-salt, binary aqueous suspensions of charged colloidal spheres of size ratio Phi = 0.57, number densities below the eutectic number density n_E, and number fractions of p = 1.00-0.40. The typical phase obtained by solidification from a homogeneous shear-melt is a substitutional alloy of body centred cubic structure. In strictly gas-tight vials, the polycrystalline solid is stable against melting and further phase transformation for extended times. For comparison, we prepare the same samples also by slow and mechanically undisturbed deionization in commercial slit cells. These cells feature a complex but well reproducible sequence of global and local gradients in salt concentration, number density and composition as induced by successive deionization, phoretic transport and differential settling of the components, respectively. Moreover, they provide an extended bottom surface suitable for heterogeneous nucleation of the beta-phase. We give a detailed qualitative characterization of the crystallization processes using imaging and optical microscopy. By contrast to the bulk samples, the initial alloy formation in slit cells is not volume-filling, and we now observe also alpha- and beta-phases with low solubility of the odd component. In addition to the initial homogeneous nucleation route, the interplay of gradients opens various further crystallization and transformation pathways leading to a great diversity of microstructures. Upon subsequent increase in salt concentration, crystals melt again. Wall-based, pebble-shaped beta-phase crystals and facetted alpha-crystals melt last. Our observations suggest that the substitutional alloys formed in bulk experiments by homogeneous nucleation and subsequent growth are mechanically stable in the absence of solid-fluid interfaces but thermodynamically metastable.Comment: Submitted to J Chem Phys. Revised version after forst Referee round. 50p, 21 figures, mainly high res. micrograph

Ileocecal Intussusception in the Adult Population: Case Series of Two Patients

Background: Intussusception is a condition found primarily in the pediatric population. In the adult population, however, intussusception is usually due to a pathological process, with a higher risk of bowel obstruction, vascular compromise, inflammatory changes, ischemia, and necrosis. Radiographic and sonographic evidence can aid in the diagnosis. Surgical intervention involving resection of affected bowel is the standard of care in adult cases of intussusception. Case Reports: We present the case of a 21-year-old female who presented to the Emergency Department with diffuse cramping abdominal pain and distention. Workup revealed ileocecal intussusception, with a prior appendectomy scar serving as the lead point discovered during exploratory laparotomy. We also present the case of a 66-year-old male, who presented with one week of intermittent lower abdominal pain associated with several episodes of nausea and vomiting. Workup revealed ileocolic intussusception secondary to adenocarcinoma of the right colon, confirmed upon exploratory laparotomy with subsequent right hemicolectomy. Conclusion: In the adult population, intussusception is usually caused by a lead point, with subsequent telescoping of one part of the bowel into an adjacent segment. While intussusception can occur in any part of the bowel, it usually occurs between a freely moving segment and eithe

Risk Factors for Extubation Failure following Neonatal Cardiac Surgery

Objective: Extubation failure after neonatal cardiac surgery has been associated with considerable postoperative morbidity, although data identifying risk factors for its occurrence are sparse. We aimed to determine risk factors for extubation failure in our neonatal cardiac surgical population. Design: Retrospective chart review. Setting: Urban tertiary care free-standing children’s hospital. Patients: Neonates (0–30 d) who underwent cardiac surgery at our institution between January 2009 and December 2012 was performed. Interventions: Extubation failure was defined as reintubation within 72 hours after extubation from mechanical ventilation. Multivariate logistic regression analysis was performed to determine independent risk factors for extubation failure. Measurements and Main Results: We included 120 neonates, of whom 21 (17.5%) experienced extubation failure. On univariate analysis, patients who failed extubation were more likely to have genetic abnormalities (24% vs 6%; p = 0.023), hypoplastic left heart (43% vs 17%; p = 0.009), delayed sternal closure (38% vs 12%; p = 0.004), postoperative infection prior to extubation (38% vs 11%; p = 0.002), and longer duration of mechanical ventilation (median, 142 vs 58 hr; p = 0.009]. On multivariate analysis, genetic abnormalities, hypoplastic left heart, and postoperative infection remained independently associated with extubation failure. Furthermore, patients with infection who failed extubation tended to receive fewer days of antibiotics prior to their first extubation attempt when compared with patients with infection who did not fail extubation (4.9 ± 2.6 vs 7.3 ± 3; p = 0.073). Conclusions: Neonates with underlying genetic abnormalities, hypoplastic left heart, or postoperative infection were at increased risk for extubation failure. A more conservative approach in these patients, including longer pre-extubation duration of antibiotic therapy for postoperative infections, may be warranted

E2-2 Dependent Plasmacytoid Dendritic Cells Control Autoimmune Diabetes

Autoimmune diabetes is a consequence of immune-cell infiltration and destruction of pancreatic β-cells in the islets of Langerhans. We analyzed the cellular composition of the insulitic lesions in the autoimmune-prone non-obese diabetic (NOD) mouse and observed a peak in recruitment of plasmacytoid dendritic cells (pDCs) to NOD islets around 8–9 weeks of age. This peak coincides with increased spontaneous expression of type-1-IFN response genes and CpG1585 induced production of IFN-α from NOD islets. The transcription factor E2-2 is specifically required for the maturation of pDCs, and we show that knocking out E2-2 conditionally in CD11c+ cells leads to a reduced recruitment of pDCs to pancreatic islets and reduced CpG1585 induced production of IFN-α during insulitis. As a consequence, insulitis has a less aggressive expression profile of the Th1 cytokine IFN-γ and a markedly reduced diabetes incidence. Collectively, these observations demonstrate a disease-promoting role of E2-2 dependent pDCs in the pancreas during autoimmune diabetes in the NOD mouse

Xanthogranulomatous Pyelonephritis in a male child with renal vein thrombus extending into the inferior vena cava: a Case Report

<p>Abstract</p> <p>Background</p> <p>We present a case of Xanthogranulomatous pyelonephritis (XGPN) in a male child with renal vein thrombus extending into the inferior vena cava. This is a rare presentation. XGPN is a rare type of renal infection characterised by granulomatous inflammation with giant cells and foamy histiocytes. The peak incidence is in the sixth to seventh decade with a female predominance. XGPN is rare in children.</p> <p>Case presentation</p> <p>An 11 year old male child presented with a history of high grade fever and chills, right flank pain and progressive pyuria for two months. He had a history of vesical calculus for which he was operated four years back. In our case, a subcapsular right nephrectomy was performed. The surgical specimens were formalin fixed and paraffin embedded. The sections were stained with routine Hematoxylin & Eosin stain. Grossly; the kidney was enlarged with adherent capsule and thickening of the perinephric tissue. The pelvicalyceal system was dilated and was filled with a cast of pus. Histological evaluation revealed diffuse necrosis of the renal parenchyma and perinephric fat. Neutrophils, plasma cells, sheets of foamy macrophages and occasional multinucleate giant cells were seen. The renal vein was partially occluded by an inflammatory thrombus with fibrin, platelets and mixed inflammatory cells. The thrombus was focally adherent to the vein wall with organization.</p> <p>Conclusions</p> <p>The clinical presentation and the macroscopic aspect, together with the histological pattern, the cytological characteristics addressed the diagnosis towards XGPN with a vena caval thrombus. Our case illustrates that the diagnosis of XGPN should be considered even in paediatric age group when renal vein and vena caval thrombi are present.</p