Hot Surface Ignition

Undesirable hot surface ignition of flammable liquids is one of the hazards in ground and air transportation vehicles, which primarily occurs in the engine compartment. In order to evaluate the safety and sustainability of candidate replacement fuels with respect to hot surface ignition, a baseline low lead fuel (Avgas 100 LL) and four experimental unleaded aviation fuels recommended for reciprocating aviation engines were considered. In addition, hot surface ignition properties of the gas turbine fuels Jet-A, JP-8, and JP-5 were measured. A test apparatus capable of providing reproducible data was designed and fabricated to experimentally investigate the hot surface ignition characteristics. A uniform surface temperature stainless steel plate simulating the wall of a typical exhaust manifold of an aircraft engine was used as the hot surface. Temperature uniformity of ±5°C was achieved on the stainless steel plate by virtue of its being bolted to a copper plate in which five automatically controlled 1000 W electrical cartridge heaters were inserted. A programmable syringe pump was used to dispense ~25 μL fuel drops onto the hot surface. Testing was performed in a quiescent environment with the exception of a mild upward flow created by an exhaust fan aiding the buoyant plume created by the hot plate. Ignition and flame propagation events were recorded using visible and mid-infrared still and video imaging. The ignition and flame propagation events are transient and occur at randomly distributed locations on the hot surface. To characterize the ignition event statistically, the surface temperature leading to at least one ignition out of the number of drops and the surface temperature resulting in the ignition of all of the drops were recorded. The results of the experiment confirmed that the experimental variations in the drop size, drop velocity, plume characteristics, surface properties including temperature changes, and the nonlinear dependence of temperature of the chemical reaction rate lead to the probabilistic nature of the ignition event. The results of the experiment are of practical value in designing vehicular ignition and safety systems

The anatomical limits of the posterior vaginal vault toward its use as route for intra-abdominal procedures

Background: The use of natural openings for abdominal surgery started at the beginning of the 21th century. A trans-Douglas endoscopic device has been designed to perform most of the intra-abdominal operations in women through the pouch of Douglas. The posterior vaginal vault is limited in size and could be damaged by an oversized instrument. This study investigates the optimal dimensions of the instrument by measuring the limiting factor in the passage. Methods: In ten female embalmed bodies the transversal and sagittal diameter of the fornix posterior vaginalis was measured by two observers. The pouch of Douglas was filled to its maximal capacity with mouldable latex through an open abdomen. By internal vaginal examination the connective tissue borders of the fornix posterior were palpated and the impression in the cast was measured. The mean value of these two diameters was evaluated in this study. The level of agreement between the observers was calculated. Results: The mean fornix posterior diameter was 2.6 cm (standard deviation, SD 0.5 cm) with a range of 2.0-3.4 cm. The mean difference between the two observers of all measurements was 0.08 cm (not significant). Both observers had an acceptable intraobserver variation. The interobserver agreement was excellent. Conclusion: Instruments with dimensions within the measured limits can be used safely for intra-abdominal operations via the natural orifice of the vagina

Platelets Boost Recruitment of CD133+ Bone Marrow Stem Cells to Endothelium and the Rodent Liver-The Role of P-Selectin/PSGL-1 Interactions

Lehwald N, Duhme C, Pinchuk I, et al. Platelets Boost Recruitment of CD133+ Bone Marrow Stem Cells to Endothelium and the Rodent Liver-The Role of P-Selectin/PSGL-1 Interactions. International journal of molecular sciences. 2020;21(17): 6431.We previously demonstrated that clinical administration of mobilized CD133+ bone marrow stem cells (BMSC) accelerates hepatic regeneration. Here, we investigated the potential of platelets to modulate CD133+BMSC homing to hepatic endothelial cells and sequestration to warm ischemic livers. Modulatory effects of platelets on the adhesion of CD133+BMSC to human and mouse liver-sinusoidal- and micro- endothelial cells (EC) respectively were evaluated in in vitro co-culture systems. CD133+BMSC adhesion to all types of EC were increased in the presence of platelets under shear stress. This platelet effect was mostly diminished by antagonization of P-selectin and its ligand P-Selectin-Glyco-Ligand-1 (PSGL-1). Inhibition of PECAM-1 as well as SDF-1 receptor CXCR4 had no such effect. In a model of the isolated reperfused rat liver subsequent to warm ischemia, the co-infusion of platelets augmented CD133+BMSC homing to the injured liver with heightened transmigration towards the extra sinusoidal space when compared to perfusion conditions without platelets. Extravascular co-localization of CD133+BMSC with hepatocytes was confirmed by confocal microscopy. We demonstrated an enhancing effect of platelets on CD133+BMSC homing to and transmigrating along hepatic EC putatively depending on PSGL-1 and P-selectin. Our insights suggest a new mechanism of platelets to augment stem cell dependent hepatic repair

Experience of Congenital Choledochal Cyst in Adults: Treatment, Surgical Procedures and Clinical Outcome in the Second Affiliated Hospital of Harbin Medical University

This study was undertaken to analyze and evaluate the diagnosis and principal treatment methods for congenital choledochal cyst, focusing on various surgical procedures and clinical outcome. A comprehensive, retrospective study was conducted on 72 adult patients who presented with choledochal cyst from 1985 to 2002. Surgical procedures were cyst excision with hepaticojejunostomy in 25 cases for type I or type IV-B, extrahepatic cyst excision with hepaticojejunostomy in 8 cases for type IV-A, extrahepatic cyst excision with modified hepaticojejunostomy in 2 cases for type IV-B, non-cyst excision with or without hepaticojejunostomy in 27 cases for types I, II, IV-A, IV-B. The early postoperative morbidity and mortality rate were 16.1% (9/62) and 6.5% (4/62) respectively, and the complication rate related to surgical procedure was 30.6% (19/62). The incidence of cholangiocarcinoma with non-cyst excision or non-operated congenital choledochal cyst was 10.8% (4/37). One patient died of primary hepatocellular carcinoma after cyst excision with hepatojejunostomy. In conclusion, our results showed that complete exci-sion of choledochal cyst for types I, II, and IV-B and complete excision of extra-hepatic choledochal cyst from the hepatic hilum in type IV-A with hepaticojejunostomy or modified hepaticojejunostomy are the treatment of choice for choledochal cyst in adult patients

A Role for NF-κB in Organ Specific Cancer and Cancer Stem Cells

Kaltschmidt C, Banz-Jansen C, Benhidjeb T, et al. A Role for NF-κB in Organ Specific Cancer and Cancer Stem Cells. Cancers. 2019;11(5): 655.Cancer stem cells (CSCs) account for tumor initiation, invasiveness, metastasis, and recurrence in a broad range of human cancers. Although being a key player in cancer development and progression by stimulating proliferation and metastasis and preventing apoptosis, the role of the transcription factor NF-κB in cancer stem cells is still underestimated. In the present review, we will evaluate the role of NF-κB in CSCs of glioblastoma multiforme, ovarian cancer, multiple myeloma, lung cancer, colon cancer, prostate cancer, as well as cancer of the bone. Next to summarizing current knowledge regarding the presence and contribution of CSCs to the respective types of cancer, we will emphasize NF-κB-mediated signaling pathways directly involved in maintaining characteristics of cancer stem cells associated to tumor progression. Here, we will also focus on the status of NF-κB-activity predominantly in CSC populations and the tumor mass. Genetic alterations leading to NF-κB activity in glioblastoma, ependymoma, and multiple myeloma will be discussed

A randomised, multi-centre, prospective, double blind pilot-study to evaluate safety and efficacy of the non-absorbable Optilene® Mesh Elastic versus the partly absorbable Ultrapro® Mesh for incisional hernia repair

<p>Abstract</p> <p>Background</p> <p>Randomised controlled trials with a long term follow-up (3 to 10 years) have demonstrated that mesh repair is superior to suture closure of incisional hernia with lower recurrence rates (5 to 20% versus 20 to 63%). Yet, the ideal size and material of the mesh are not defined. So far, there are few prospective studies that evaluate the influence of the mesh texture on patient's satisfaction, recurrence and complication rate. The aim of this study is to evaluate, if a non-absorbable mesh (Optilene^®Mesh Elastic) will result in better health outcomes compared to a partly absorbable mesh (Ultrapro^®Mesh).</p> <p>Methods/Design</p> <p>In this prospective, randomised, double blind study, eighty patients with incisional hernia after a midline laparotomy will be included. Primary objective of this study is to investigate differences in the physical functioning score from the SF-36 questionnaire 21 days after mesh insertion. Secondary objectives include the evaluation of the patients' daily activity, pain, wound complication and other surgical complications (hematomas, seromas), and safety within six months after intervention.</p> <p>Discussion</p> <p>This study investigates mainly from the patient perspective differences between meshes for treatment of incisional hernias. Whether partly absorbable meshes improve quality of life better than non-absorbable meshes is unclear and therefore, this trial will generate further evidence for a better treatment of patients.</p> <p>Trial registration</p> <p>NCT00646334</p