Diagnostic delay in inflammatory bowel disease increases the risk of intestinal surgery

AIM To investigate the factors affecting diagnostic delay and outcomes of diagnostic delay in inflammatory bowel disease(IBD) METHODS We retrospectively studied 165 patients with Crohn's disease(CD) and 130 patients with ulcerative colitis(UC) who were diagnosed and had follow up durations > 6 mo at Korea University Ansan Hospital from January 2000 to December 2015. A diagnostic delay was defined as the time interval between the first symptom onset and IBD diagnosis in which the 76^(th) to 100^(th) percentiles of patients were diagnosed.RESULTS The median diagnostic time interval was 6.2 and 2.4 mo in the patients with CD and UC, respectively. Among the initial symptoms, perianal discomfort before diagnosis(OR = 10.2, 95%CI: 1.93-54.3, P = 0.006) was associated with diagnostic delays in patients with CD; however, no clinical factor was associated with diagnostic delays in patients with UC. Diagnostic delays, stricturing type, and penetrating type were associated with increased intestinal surgery risks in CD(OR = 2.54, 95%CI: 1.06-6.09; OR = 4.44, 95%CI: 1.67-11.8; OR = 3.79, 95%CI: 1.14-12.6, respectively). In UC, a diagnostic delay was the only factor associated increased intestinal surgery risks(OR = 6.81, 95%CI: 1.12-41.4).CONCLUSION A diagnostic delay was associated with poor outcomes, such as increased intestinal surgery risks in patients with CD and UC.

Fabrication and characterization of the Ti-Ca-P composites by vacuum sintering

Using Ti and biphasic calcium phosphate (BCP) pow-ders, Ti-Ca-P composites which contained 0 - 30 vol.% BCP powders initially, were fabricated by vac-uum sintering at two different sintering temperatures, 1300°C and 1400°C. Detailed microstructural char-acteristics of the resulting composites were investi-gated. Mechanical properties like compressive strength, Vickers hardness were evaluated and they showed decreasing trend with the increasing initial BCP content. The x-ray diffraction (XRD) profiles revealed that extensive chemical reaction occurred and the initial BCP was degraded and formed CaO, TiO2, TiP, CaTiO3. However, the cell viability by MTT assay and cell proliferation behavior through one cell morphology analysis showed excellent in-creasing trend in biocompatibility which makes this materials suitable for hard tissue aid material.And the composite containing 30 vol.% BCP content with Ti sintered at 1400°C showed excellent biocompati-bility with the Vickers Hardness value 108.8 HV and the compressive strength value 303.7 MPa.

Oxidation Behavior of Fe-36Ni and Fe-46Ni Alloy Scraps

Oxidation study of Fe-36Ni and Fe-46Ni alloys was conducted on the effect of temperature under a 0.2 atm oxygen partial pressure. The weight of both specimens was continuously measured by TGA （thermogravimetric apparatus） at various temperatures and it was found that the weigh was gained with an increase of temperature. The oxidation behavior of Fe-36/46Ni alloys was found to be followed by parabolic rate law and the rate constants were linearly proportional to the temperature. In addition, activation energies of Fe-36Ni and Fe-46Ni alloys were calculated to be 106.49 kJ/mol and 58.99 kJ/mol, respectively. The cross sectional area of oxide scale was examined by SEM （scanning electron microscopy） and analyzed by XRD （X-ray diffraction） and EDX （energy-dispersive X-ray spectroscopy）.

Experimental and Computational Studies on Coanda Nozzle Flow for the Air Knife Application

To control the film thickness of zinc in the process of continuous hot-dip galvanizing, it is known from the early days that the gas wiping through an air knife is the most effective one. The gas wiping using in galvanizing process brings about a problem of splashing from the strip edge for a certain high speed of coating. So, in the present study, the effects of the deflection angle of Coanda nozzle on jet structure and the distribution of impinging pres- sure at the plate surface are investigated numerically and experimentally. In numerical analysis, the governing equations consisted of three-dimensional time dependent full Navier-Stokes equations, standard k-ε turbulence model to solve turbulent stTess and so on are employed. In experiment, 16 channel pressure scanning valve and 3-axis auto traversing unit are used to measure the impinging pressure at the strip surface. As a result, it is found that the smaller the deflection angle for the same nozzle slit of air knife is, the larger the impinging pressure is. To reduce the size of separation bubble and to enhance the cutting ability, it is recommendable to use an air knife with the Coanda nozzle.

Enhanced Oxidation Resistance of Iron Nanoparticles via Surface Modification in Chemical Vapor Condensation Process

In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance in ordinary condition, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in usual air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below 130℃ in air was 10-40 times higher than that of the normally passivated particles.