Investigation of transient fluid flow and heat transfer in a continuous casting tundish by numerical analysis verified with nonisothermal water model experiments

The tundish process is complicated due to the periodic nature of its operation during the changing of ladles, which makes it both a transient and nonisothermal process. A nonisothermal water model, with temperature variations in the inlet stream, is described in this article. A three-dimensional (3-D) transient mathematical model to simulate the fluid flow and heat transfer in this water model is also introduced. From the experimental and numerical results, it is shown that there is a significant thermal buoyancy force contributing to the flow in this nonisothermal water model.     

Corneal scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study: baseline prevalence and repeatability of detection

Fibroblast growth factor-16 (FGF-16) is the most recent member of the FGF family to be cloned. Since the biologic activity of rat FGF-16 (rFGF-16) was unknown, and this protein has no apparent signal sequence, we transformed its entire cDNA into Escherichia coli for high-level expression and further characterization of this novel protein. An attempt was made to purify the expressed protein from the supernatant of mechanically lysed cells using sequential cation-exchange chromatography. This resulted in a gradual loss of the protein as precipitate throughout the purification process. In addition to precipitation during purification, sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the partially purified materials showed a cluster of protein bands around 20k to 29k. Sequence analysis of the major bands indicated that two N-terminal truncations had occurred, during E. coli fermentation, purification, or both. The largest truncation resulted in the removal of the 34 N-terminal amino acids, including the initiation codon methionine. We cloned d34 rFGF-16, expressed the gene in E. coli, and developed a purification process for this form. Even with this truncated form, precipitation was a problem. We were largely able to overcome this problem, however, by including EDTA throughout the purification process. We have characterized the structure of purified d34 rFGF-16 extensively using circular dichroism, Fourier transform infrared spectroscopy, and sedimentation velocity analysis. These studies revealed that the protein has a distinct tertiary structure, consists primarily of beta-strands, has a weak tendency to self-associate, and is fairly extended. We then performed biologic assays which showed that d34 rFGF-16 induces oligodendrocyte proliferation in vitro, and induces hepatocellular proliferation and increased liver weight in vivo. In summary, FGF-16, a novel FGF family member, has both unique structural and biological properties.     

Physical modeling and control of dynamic foaming in an LD-converterprocess

This paper deals with physical modeling and control of dynamic foaming in the LD-converter process. An experimental setup consisting of a water model, digital signal processor, and PC hardware is built and shown to be useful for studying dynamic foaming. Furthermore, a foam height estimation algorithm is presented and validated through experiments. Finally, sound signals from the LD-converter and water model are compared and similarities between them are found     

High Temperature Oxidation of the Austenitic (35Fe27Cr31Ni) Alloy Sanicro 28 in O2 + H2O Environment

The present study investigates the high temperature oxidation of alloy Sanicro 28 (35Fe27Cr31Ni) in 5% O₂ and in 5% O₂ + 40% H₂O. Polished steel coupons were isothermally exposed in a tube furnace at 600, 700 and 800 °C for up to 168 h. The samples were investigated by gravimetry, grazing angle X-ray diffraction (XRD), Auger electron spectroscopy (AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning transmission electron microscopy/energy dispersive X-rays (STEM/EDX). The results show that the material forms a protective scale in both environments. The scale is duplex. The inner part of the scale consists of corundum type chromium-rich (Cr _x Fe_1?x )₂O₃, and the outer layer consists of spinel type oxide. Chromia is lost from the protective oxide by vaporization of CrO₂(OH)₂ in O₂ + H₂O environment. The capacity of Sanicro 28 to suffer chromia vaporization without forming a rapidly growing iron-rich oxide is attributed to its high Cr/Fe ratio. The spinel formed at the oxide/gas interface could in addition be beneficial for oxidation behavior in wet oxygen because it may slow down chromia evaporation.     

Prodrugs for targeting hypoxic tissues: regiospecific elimination of aspirin from reduced indolequinones

We report the cases of three patients with anorexia nervosa (AN) who each recovered rapidly after experiencing a life-threatening episode with severe thrombocytopenia. All three cases were the typical restricting-type of AN, occurring in adolescence. They refused to be admitted to a hospital until their general condition had been severely deteriorated. Their lowest platelet counts were 2.9, 4.6, and 2.3 x 10(4)/mm3, respectively. Apparent hemorrhagic tendencies, such as purpura, gingival and nasal bleeding, and gastrointestinal bleeding were observed. The bone marrow examination showed apparent hypoplasia in two patients. No evidence of disseminated intravascular coagulation or autoantibody to platelets was detected. The platelet counts recovered rapidly by water and nutritional supplementation. The recovery from the AN itself was excellent in all three patients without specific psychotherapy.     

Stochastic optimization of acoustic response – a numerical and experimental comparison

The objective of the work presented is to compare results from numerical optimization with experimental data and to highlight and discuss the differences between two fundamentally different optimization methods. The problem domain is minimization of acoustic emission and the structure used in the work is a closed cylinder with forced vibration of one end. The optimization method used in this paper is simulated annealing (SA), a stochastic method. The results are compared with those from a gradient-based method used on the same structure in an earlier paper (see Tinnsten 2000).     

Multiplexed DNA sequencing and diagnostics by hybridization with enriched stable isotope labels

A new DNA diagnostic and sequencing system has been developed that uses time-of-flight resonance ionization mass spectrometry (TOF-RIMS) to provide a rapid method of analyzing stable isotope-labeled oligonucleotides in form 1 sequencing by hybridization (SBH). With form 1, the DNA is immobilized on a nylon membrane and enriched isotope-labeled individual oligonucleotide probes are free to seek out complementary DNAs during hybridization. The major advantage of this new approach is that multiple oligonucleotides can be labeled with different enriched isotopes and can all be simultaneously hybridized to the genosensor matrix. The probes can then be simultaneously detected with TOF-RIMS with high selectivity, sensitivity, and efficiency. By using isotopically enriched tin labels, up to 10 labeled oligonucleotides could be examined in a single hybridization to the DNA matrix. Greater numbers of labels are available if rare earth isotopes are employed. In the present study, matrices containing three different DNAs were prepared and simultaneously hybridized with two different probes under a variety of conditions. The results show that DNAs, immobilized on nylon surfaces, can be specifically hybridized to probes labeled with different enriched in isotopes. Discrimination between complementary and noncomplementary sites of better than 100 was obtained in multiplexed samples. This new SBH method, which employs stable isotopic labels to locate target DNAs and TOF-RIMS to detect the labels, will be a very versatile and extensive multiplexing method.     

Erythema migrans-like rash illness at a camp in North Carolina: a new tick-borne disease?

BACKGROUND: Borrelia burgdorferi, the causative agent of Lyme disease, has never been isolated from a patient thought to have acquired Lyme disease in any southeastern state. OBJECTIVE: To investigate 14 cases of an erythema migrans (EM)-like rash illness that occurred during 2 summers at an outdoor camp in central North Carolina in an effort to determine the etiologic, epidemiological, and clinical aspects of this illness. METHODS: Using active surveillance, we identified cases of clinically diagnosed EM in residents and staff of the camp. We collected clinical and demographic information; history of exposure to ticks; acute and convalescent serum antibodies to B. burgdorferi, Rickettsia rickettsii, and Ehrlichia chaffeensis; and cultures for spirochetes from biopsy specimens of skin lesions. Serum samples from a group of residents and staff who did not develop rashes were tested for the same antibodies. We speciated ticks removed from people and collected from vegetation. RESULTS: We identified 14 cases of EM-like rash illness during the 2 summers. Of the 14 case-patients, 10 had associated mild systemic symptoms and 1 had documented fever. All 14 case-patients had removed attached ticks, and 8 remembered having removed a tick from the site where the rash developed a median of 12 days earlier (range, 2-21 days). One tick removed from the site where a rash later developed was identified as Amblyomma americanum, the Lone Star tick; 97% of ticks collected from vegetation and 95% of ticks removed from people were A. americanum. No spirochetes were isolated from skin biopsy specimens. Paired serum samples from 13 case-patients did not show diagnostic antibody responses to B. burgdorferi or other tick-borne pathogens. CONCLUSIONS: This investigation suggests the existence of a new tick-associated rash illness. We suspect that the disease agent is carried by A. americanum ticks. In the southern United States, EM-like rash illness should no longer be considered definitive evidence of early Lyme disease.     

Evaluation of natural Psoroptes ovis (Acarina: Psoroptidae) soluble proteins as candidate vaccine immunogens

In this study potential vaccine candidate immunogens were identified and evaluated in a vaccine challenge trial. Calves vaccinated with a partially purified fraction of Psoroptes ovis-soluble proteins had 8 of 14 calves free of palpable lesions 8 wk after a challenge infestation. A self-grooming behavioral response elicited by a pruritic immediate-type allergic reaction was believed to be an effector in protecting the vaccinated calves from a clinical P. ovis infestation.