Heat Transfer of Ca (NO3)2-KNO3 Molten Salt Mixtures for Austempering and Martempering Processes of Steels.

Molten salts are highly effective as a quenching medium for austempering and martempering processes, enabling precise control of cooling rates to achieve the desired microstructures and mechanical characteristics in steel components. One such promising molten salt is a multicomponent Ca (NO3)2-KNO3 molten salt. The current work explores the cooling severity of molten Ca (NO3)2-KNO3 mixtures, which are commonly used for such purposes. The said mixture, with varying concentrations and bath temperatures was used for quenching the Inconel probe with thermocouples. The temperature data extracted was used to determine the transient heat flux developed at the metal-quenchant interface. A set of critical points were assessed against the peak heat extraction rates. Additionally, the fluctuation of mean heat flux and surface temperature in relation to these crucial points were plotted, along with changes in composition and bath temperature of the quench media. The cooling intensity of these quench solutions, as measured by Inconel probes, correlated well with the average hardness values observed in steel probes. The level of homogeneity in heat transmission, as measured by the spatial variance of the normalized heat energy, decreased as the percentage of KNO3 in the quench medium increased.

Endoscopic Band Ligation of Bleeding Duodenal Varices.

Ectopic variceal bleeding is an uncommon cause of gastrointestinal bleeding and carries a high mortality. Management depends on provider comfort and resource availability as treatment guidelines are lacking due to the infrequent occurrence of bleeding ectopic varices. We present a case of a middle-aged woman who presented with melena and anemia requiring transfusion. She was diagnosed with cirrhosis, and computed tomography of the abdomen revealed active bleeding at the proximal duodenum. She underwent emergent esophagogastroduodenoscopy, which showed actively bleeding duodenal varices secondary to portosystemic shunt from portal hypertension. Endoscopic hemostasis was achieved with variceal band ligation, a useful modality when alternative methods of emergent variceal management are unavailable. Given the risk of recurrent bleeding, the patient underwent embolization of varices by interventional radiology.

Small Bowel Obstruction: A Rare Presentation of the Inferior Pancreaticoduodenal Artery Pseudoaneurysm Bleed.

Intra-abdominal and intramural hematomas are well-known complications of pseudoaneurysms. We present a case of small bowel obstruction as a result of external mechanical compression from hematoma. Bleeding was localized to the pseudoaneurysm of the gastroduodenal artery and inferior pancreaticoduodenal artery. Angiography was used to control the bleeding with coil embolization. This rare clinical manifestation represents just one of the symptoms associated with pseudoaneurysms of the gastrointestinal tract. Therapeutic options are discussed along with a review of the literature.

Endoscopic Ultrasound-Directed Transgastric Endoscopic Retrograde Cholangiopancreatography for Removal of Cystic Duct Coils: A Novel Application of an Emerging Technique.

The altered anatomy of patients after Roux-en-Y gastric bypass (RYGB) surgery creates technical challenges for endoscopic and surgical treatment of gallstones. We present a unique case of a post-RYGB patient with complicated gallbladder surgery requiring coiling and embolization of the cystic duct for bile leak. The cystic duct coils migrated out into the bile duct forming a nidus for infection and biliary obstruction, which was resolved using the novel endoscopic ultrasound-directed transgastric routine endoscopic retrograde cholangiopancreatography technique, with successful transpapillary removal of cystic duct coils in RYGB anatomy.

PTPN11 mutations in Noonan syndrome type I: detection of recurrent mutations in exons 3 and 13.

We surveyed 16 subjects with the clinical diagnosis of Noonan Syndrome (NS1) from 12 families and their relevant family members for mutations in PTPN11/SHP2 using direct DNA sequencing. We found three different mutations among five families. Two unrelated subjects shared the same de novo missense substitution in exon 13 (S502T); an additional two unrelated families had a mutation in exon 3 (Y63C); and one subject had the amino acid substitution Y62D, also in exon 3. None of the three mutations were present in ethnically matched controls. In the mature protein model, the exon 3 mutants and the exon 13 mutant amino acids cluster at the interface between the N' SH2 domain and the phosphatase catalytic domain. Six of eight subjects with PTPN11/SHP2 mutations had pulmonary valve stenosis while no mutations were identified in those subjects (N = 4) with hypertrophic cardiomyopathy. An additional four subjects with possible Noonan syndrome were evaluated, but no mutations in PTPN11/SHP2 were identified. These results confirm that mutations in PTPN11/SHP2 underlie a common form of Noonan syndrome, and that the disease exhibits both allelic and locus heterogeneity. The observation of recurrent mutations supports the hypothesis that a special class of gain-of-function mutations in SHP2 give rise to Noonan syndrome.

Structural determinants present in the C-terminal binding protein binding site of adenovirus early region 1A proteins.

The C-terminal binding protein (CtBP) has previously been shown to bind to a highly conserved six-amino acid motif very close to the C terminus of adenovirus early region 1A (Ad E1A) proteins. We have developed an enzyme-linked immunosorbent assay that has facilitated the screening of synthetic peptides identical or similar to the binding site on Ad E1A for their ability to bind CtBP and thus inhibit its interaction with Ad12 E1A. It has been shown that amino acids both C-terminal and N-terminal to the original proposed binding site contribute to the interaction of peptides with CtBP. Single amino acid substitutions across the binding site appreciably alter the Kd of the peptide for CtBP, indicative of a marked reduction in the affinity of the peptide for CtBP. The solution structures of synthetic peptides equivalent to the C termini of both Ad5 and Ad12 E1A and two substituted forms of these have been determined by proton NMR spectroscopy. Both the Ad12 and Ad5 peptides dissolved in trifluoroethanol/water mixtures were found to adopt regular secondary structural conformations seen as a series of beta-turns. An Ad12 peptide bearing a substitution that resulted in only very weak binding to CtBP (Ad12 L258G) was found to be random coil in solution. However, a second mutant (Ad12 V256K), which bound to CtBP rather more strongly (although not as well as the wild type), adopted a conformation similar to that of the wild type. We conclude that secondary structure (beta-turns) and an appropriate series of amino acid side chains are necessary for recognition by CtBP.