Effects of bubble expansion on wear of refractory for BOF stirring plugs embedding tuyères

Single tuyère wear tests of MgO-C and burnt magnesia bricks were performed to study relations between tuyère characteristics and refractory wear parameters, with emphasis on the wear zone geometry. Either Ar or N₂ was used as injected gas and the test temperature for liquid metal was 1400, 1550 and 1700°C. A bubble expansion wear mechanism was proposed for the mechanical wear of tuyère refractory by comparison of bubble radii and the wear zone geometry of refractory bricks and H₃BO₃ disks. Equations are derived to predict the deep and shear wear zone radii and the refractory wear rate at values of the nominal Mach number up to one. These equations can be used for an optimum design of single- and multiple-tuyère plugs for combined blowing BOF, as well as for optimization of gas stirring operation to reduce the wear of MgO-C refractory around the tuyère and for the plugs.     

Mathematical models of diffusion-limited gas bubble dynamics in tissue

Mathematical models of bubble evolution in tissue have recently been incorporated into risk functions for predicting the incidence of decompression sickness (DCS) in human subjects after diving and/or flying exposures. Bubble dynamics models suitable for these applications assume the bubble to be either contained in an unstirred tissue (two-region model) or surrounded by a boundary layer within a well-stirred tissue (three-region model). The contrasting premises regarding the bubble-tissue system lead to different expressions for bubble dynamics described in terms of ordinary differential equations. However, the expressions are shown to be structurally similar with differences only in the definitions of certain parameters that can be transformed to make the models equivalent at large tissue volumes. It is also shown that the two-region model is applicable only to bubble evolution in tissues of infinite extent and cannot be readily applied to bubble evolution in finite tissue volumes to simulate how such evolution is influenced by interactions among multiple bubbles in a given tissue. Two-region models that are incorrectly applied in such cases yield results that may be reinterpreted in terms of their three-region model equivalents but only if the parameters in the two-region model transform into consistent values in the three-region model. When such transforms yield inconsistent parameter values for the three-region model, results may be qualitatively correct but are in substantial quantitative error. Obviation of these errors through appropriate use of the different models may improve performance of probabilistic models of DCS occurrence that express DCS risk in terms of simulated in vivo gas and bubble dynamics.     

Experimental study on rapid expansion of soft tissue

Nine white pigs weighing about 15 kg were divided into three groups: rapid expansion group (REG), conventional expansion group (CEG) and control group (CON). Expansion was carried out under monitoring of interal pressure of the expander and blood flow of the skin over the expander. After completion of expansion, hemodynamic, physical, histologic and ultrastructure changes of the expanded skin were measured and recorded. The study showed: (1) The immediate retraction ratios of skin of three groups were 41.37%, 20.82% and 10.01%, respectively (P < 0.01). (2) The thickness of the epidermis of the three groups was not statistically different, though the dermis of the expanded skin was thinner than that of the control (P < 0.01). (3) The density of collagen in the dermis of the three groups was 80.57 +/- 5.47, 79.49 +/- 6.31 and 82.72 +/- 2.69, respectively; the density of elastin of the three groups was 2.88 +/- 1.24, 2.77 +/- 0.74 and 2.56 +/- 0.63, respectively (P < 0.05). We concluded that the delay phenomenon of the expanded flap depends mainly on the intensity of expansion. The immediate retraction ratio of the rapidly expanded skin was greater than that of conventionally expanded skin. Rapid expansion also results in tissue hypertrophy but does not cause destruction of collagen. With proper calculating the size of the defect and estimating immediate skin retraction, rapid expansion is feasible in clinical applications.     

Clinical application of repeated tissue expansion

Acetabular fractures due to bone insufficiency are rare and difficult to diagnose based on clinical findings alone. Plain films are often normal for a long period of time. We report two cases of acetabular fractures in women aged 78 and 90 years, respectively. An acetabular fracture should be considered in elderly females with sudden onset of pain in the groin occurring immediately upon weight-bearing, a clinostatic syndrome, and increased radionuclide uptake by the acetabulum. Computed tomography and magnetic resonance imaging are useful when the diagnosis remains in doubt.     

Ex vivo expansion of haemopoietic progenitor cells

Over the last few years, techniques have become available that allow the extensive proliferation of haemopoietic progenitor cells in ex vivo culture systems. The most commonly used method involves a simple liquid suspension culture system supplemented with a range of cytokines. Alternatively, more complex systems have been devised in which the formation of a stromal layer is required. Large increases in total cell numbers and committed progenitor cells can be readily obtained and, with some techniques, significant expansion of primitive haemopoietic cells has been demonstrated. Although these strategies have several potential applications, few clinical studies have been performed. It has been shown that infusion of ex vivo cultured cells is well tolerated with no associated toxicity. However, it is still unclear whether these culture systems sustain sufficient numbers of long-term repopulating cells to secure durable engraftment following myeloablative therapy. In gene therapy studies, ex vivo expansion of stem cells should improve the efficiency of gene transduction to enable the production of genetically modified cells that are capable of expressing the gene of interest for extended periods of time.     

Effects of sentence constraint on priming in natural language comprehension.

In 4 cross-modal naming experiments, researchers investigated the role of sentence constraint in natural language comprehension. On the sentence constraint account, incoming linguistic material activates semantic features that in turn pre-activate likely upcoming words. The 1st and 2nd experiments investigated whether stimulus offset asynchrony played a critical role in previous studies supporting the sentence constraint account. The 3rd and 4th experiments examined further predictions of the sentence constraint account, in particular whether pre-activated words would compete for activation. In Experiment 3, the researchers manipulated whether an expected target word had a close competitor and found that response to the expected word was facilitated regardless of the proximity of a competitor. The 4th experiment established that close competitors were primed by the sentence frames and should have been available to compete with expected target words. Thus, word-level representations did not compete for activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of synthetic detergents on in vivo activity of tissue phosphatases and succinic dehydrogenase from Mystus vittatus

African catfish (Mystus vittatus) were exposed to three sub-lethal concentrations of Swascofix E45 (13.8, 9.2 and 4.6 mg/l) and Swascol 3L (69.3, 46.2 and 23.1 mg/l) for 15 and 30 days, and their effects on alkaline and acid phosphatase, and succinic dehydrogenase in liver, kidney and intestine were measured. The enzymes were found to be inhibited in all the tissues. Maximum inhibition (38.44%) was observed in liver alkaline phosphatase activity after 30 days with the highest concentration of Swascofix E45 and the lowest inhibition (0.118%) was found in kidney acid phosphatase activity with the lowest concentration of Swascol 3L after 15 days. Insignificant enzyme stimulation in some cases was also observed.     

High-resolution microscopic determination of hepatic NADH fluorescence for in vivo monitoring of tissue oxygenation during hemorrhagic shock and resuscitation

Psychopharmacological studies using caffeinated beverages or caffeine have rarely considered temporal effects on psychological and physiological function or the specific contribution of caffeine, hot water, or beverage type to the observed effects. The effect of 400 ml hot tea, coffee, and water consumption on systolic and diastolic blood pressure (SBP and DBP), heart rate, skin conductance (a measure of sympathetic nervous system activation), skin temperature, salivary cortisol, and mood were monitored in 16 healthy caffeine-withdrawn (14 h) subjects in a complete crossover design. Beverages were ingested with/without 100 mg caffeine and milk (tea/coffee only). Hot beverage ingestion rapidly increased skin conductance and temperature (+1.7 degrees C) with peak effects observed only 10-30 min post-consumption. Caffeine in the beverage rapidly augmented skin conductance responses but, in contrast to the effect of hot water, reduced the skin temperature response and increased SBP (+2.8 mmHg) and DBP (+2.1 mmHg) 30-60 min post-consumption. Both caffeine and milk addition to beverages independently improved mood and reduced anxiety 30 and 60 min post-consumption. Milk addition had no other effects apart from attenuating the transient increase in physiological responses associated with the drinking phase. There were no effects of beverage consumption on salivary cortisol or of beverage vehicle on salivary caffeine levels, the latter indicating that caffeine pharmacokinetics was similar in both tea and coffee, and not different from caffeinated water. In keeping with this, the responses to tea and coffee ingestion were similar and largely accounted for by the effects of hot water and caffeine. However, tea potentiated the increase in skin temperature compared to coffee and water indicative of a greater vasodilatory response plausibly related to the presence of flavonoids in tea. We conclude that ingestion of hot caffeinated beverages stimulates physiological processes faster than hitherto described, primarily via the effects of hot water and caffeine, but with beverage type and milk playing important modulatory roles.     

Risk factors for complications in pediatric tissue expansion

Tissue expansion in children has been associated with complication rates of 20 to 40 percent. A critical analysis of 6 years' (1988-1993) experience with 180 expanders placed in 82 consecutive children was performed to identify those factors which predispose to complications. Major and minor complications each occurred in 9 percent of patients. The factors associated with a statistically significant increase in complications were burns and soft-tissue loss, patient age under 7 years, use of internal expander ports, and a history of two or more prior expansions. In addition, complications were significantly more likely to occur within the first 90 days than during any subsequent expansion. Factors that did not influence complication rate included patient gender, wound drainage upon expander insertion or removal, intraoperative use of antibiotic irrigation, number of expanders placed, use of customized expanders, and operating surgeon.     

Effects of 4-hydroxyamphetamine on in vivo brown adipose tissue thermogenesis and feeding behavior in the rat.

Examined the influence of 4-hydroxyamphetamine (4-OHAM) on food and water intake and in vivo brown adipose thermogenesis in 2 experiments with 22 female Long-Evans rats. In Exp I, Ss were treated with 4-OHAM (0.25, 0.50, 1, or 2 mg/kg, ip) prior to assessment of interscapular brown adipose tissue (IBAT) thermogenesis. The 4-OHAM treatment induced dose-dependent activation of IBAT thermogenesis consistent with the enhanced serum levels of norepinephrine and epinephrine observed in 4-OHAM-treated Ss immediately after temperature measurement. In Exp II, the influence of 4-OHAM on food and water intake was assessed during 120-min test intervals in Ss fed food and water ad lib. Although there was a trend for 4-OHAM to increase water intake, there was no significant effect of 4-OHAM (0.40, 0.80, 1, 2, and 4 mg/kg) on either food or water intake. Data suggest that IBAT thermogenesis does not play a role in the anorexia induced by amphetamine or in the regulation of feeding. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of halothane on mucociliary activity in vivo

The effect of halothane on mucociliary activity in the rabbit maxillary sinus in vivo was recorded photoelectrically. Administration of halothane (1%, 2% or 4%) into the maxillary sinus induced a temporary acceleration of mucociliary activity. The peak increase (39.1% +/- 9.1%, p < 0.05, n = 5) was seen after the 4% concentration. Long-term exposure (60 minutes) of the maxillary sinus to halothane (2%) first induced an increase of 28.4% +/- 4.6% (p < 0.05, n = 6), lasting approximately four minutes, and followed after about 15 minutes by a decrease of mucociliary activity. The maximum decrease during the 60-minute period was 19.6% +/- 2.8% (p < 0.05, n = 6). Mucociliary activity returned to its baseline level approximately 25 minutes after withdrawal of halothane. Halothane delivered to the rabbit through a tracheal cannula at 1.1% for 60 minutes did not impair mucociliary activity in the maxillary sinus. On the contrary, it initially stimulated mucociliary activity, 19.9% +/- 2.7% (p < 0.05, n = 5). There was also an initial increase in respiratory rate from 62 +/- 7.3 to 89 +/- 12.9 breaths per minute (p < 0.05), which was noticeable after approximately 10 seconds and lasted 4 to 5 minutes. The dose-dependent increase in mucociliary activity seen after short-term exposure to halothane is probably due to stimulation of afferent C fibers, because halothane may be considered an airway irritant. The reversible depressant effect seen after 15 minutes of exposure is in accordance with findings in previous studies in vitro. The mechanism by which halothane impairs mucociliary activity is at present not known. However, halothane administered to the lower airways does not impair mucociliary activity in the maxillary sinus, indicating that halothane affects the ciliated epithelium directly and that the state of anesthesia itself has no effect on mucociliary activity.     

Histomorphologic evaluation of guinea pig skin and soft tissue after controlled tissue expansion

To evaluate the histologic changes attendant on tissue expansion in the guinea pig, self-inflating implants were placed in the dorsal subcutaneous space and the tissue response was sequentially studied at periods ranging from 1 to 18 weeks. Fixation artifacts have been minimized. The cellular response is relatively benign. The epidermis does not undergo thinning during expansion, although dermis and panniculus carnosus become significantly thinner. Atrophy of panniculus muscle is demonstrable. This study supports the hypothesis that tissue expansion results in a net gain of donor tissue.     

Immediate shock deficit in fear conditioning: Effects of shock manipulations.

Pavlovian contextual fear conditioning occurs when an aversive unconditional stimulus (US), such as a footshock, is presented to a rat shortly after it is placed in an experimental context. Contextual fear conditioning does not occur when the shock is presented immediately upon placement of the rat in the novel chamber. In the present study, the authors report that increasing either the number of immediate shock sessions (Experiment 1) or the immediate shock duration (Experiment 2) did not reverse this deficit. However, immediate shock seems to sensitize subsequent context conditioning (Experiment 3). These findings suggest that the associative deficit produced by immediate shock is not related to the rat's ability to process the footshock US. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Value of tissue expansion in total reconstruction of the external ear]

By recalling the imperatives of auricular reconstruction, the author analyses the indications for tissue expansion in this area. This expansion can be performed preoperatively or intraoperatively, directly on the ear, indirectly, away from the ear. In the light of his experience, illustrated by three clinical cases, the author considers preoperative indirect expansion to be the most useful, by placing the expander underneath the scalp.     

Effects of the constraint parameter triaxial stress on the failure behaviour of steels

The constraint parameter triaxial stress which results from loading types and component geometries plays an important role in the failure behaviour of materials. Especially the local failure initiation of materials depends very strongly on triaxial stress. The failure behaviour of a material under different stress states (i.e. different constraint) differs. In this paper effects of triaxial stress on the failure behaviour of steels are presented by means of theoretical analysis, experiments and finite-element-calculations. A theoretical model describing the effects of triaxial stress on failure initiation of materials has been developed based on theoretical analysis. Corresponding experiments were conducted to determine the material constants in the failure model of materials. In order to obtain local damage parameters finite-element calculations have been conducted. According to the results from theoretical analysis, experiments and finite-element calculations the damage curves of materials, in which the critical equivalent plastic strain is plotted as a function of triaxial stress, have been obtained. Furthermore, the failure behaviour of materials under different triaxial stresses has been discussed.     

Pharmacological characterization of novel tissue kallikrein inhibitors in vivo

In this study we have investigated the effect of novel tissue kallikreins on the plasma protein exudation induced by porcine pancreatic kallikrein (PPK) in the rabbit skin in vivo. The tissue kallikrein inhibitors here described were synthesized based on analogues of peptide substrates for tissue kallikreins. The intradermal injection of PPK and rabbit urinary kallikrein, but not of rabbit plasma kallikrein, significantly increased the microvascular permeability leading to local oedema formation in the rabbit skin. At the dose of 3-200 nmol/site, the intradermal co-administration of the tissue kallikrein inhibitors Bz-F-F-S-R-EDDnp (Ki = 0.1 microM; ESP5), PAC-F-S-R-EDDnp (Ki = 0.7 microM; ESP6), Bz-F-F-A-P-R-NH2 (Ki = 7.8 microM; ESP8), PAC-F-F-R-P-R-NH2 (Ki = 0.3 microM; ESP9) and Bz-F-F-S-R-NH2 (Ki = 0.3 microM; ESP11) dose-dependently inhibited the plasma protein exudation induced by PPK. The most potent compound was ESP6 (IC25 = 7.8 nmol/site) followed by ESP5 (IC25 = 14.2 nmol/site), ESP8 (IC25 = 25 nmol/site), ESP9 (IC25 = 30 nmol/site) and ESP11 (IC25 = 50.4 nmol/site). The compounds Bz-F-F-R-P-R-NH2 (Ki = 0.5 microM; ESP1), Bz-F-F-pNa (Ki = 0.4 microM; ESP3), Bz-F(NH2)-F-R-P-R-NH2 (Ki = 1.1 microM; ESP7) and Bz-F-F-S-P-R-NH2 (Ki = 4.6 microM; ESP10) had no significant effect on the PPK-induced plasma protein exudation in doses up to 200 nmol/site. ESP6 also inhibited the PPK-induced plasma protein exudation when administered systemically. This compound may constitute a useful tool to further investigate both the physiological and pathological role of tissue kallikreins.     

Effects of norepinephrine on right ventricular function in septic shock patients

OBJECTIVE: To study the effects of norepinephrine on right ventricular function in patients with hyperdynamic septic shock. DESIGN: Prospective, open study. SETTING: A 15 bed ICU in a university hospital. PATIENTS: 9 patients with hyperdynamic septic shock (SBP < 90 mmHg, Cl > or = 4 l.min-1.m-2, SVRI < or = 850 dynes.s.cm-5m-2 and oliguria). INTERVENTIONS: Plasma volume expansion was used to correct a suspected volume deficit and then, norepinephrine infusion was started and titrated to restore systemic blood pressure to the normal range (mean infusion rate: 1.1 +/- 0.2 mcg.kg-1.min-1). Norepinephrine was the only vasoactive agent used in these patients. MEASUREMENTS AND RESULTS: A modified Swan-Ganz catheter mounted with a fast response thermistor was inserted in each patient, allowing repeated measurements of RVEDVI and RVEF. At time of inclusion to the study, all but one patient had elevated MPAP (23 +/- 4 mmHg) and RVEF < or = 50%, and all patients had RVEDVI > or = 90 ml.m-2. During norepinephrine infusion, MAP increased from 51 +/- 9 to 89 +/- 10 mmHg (p < 0.0001), PVRI increased from 204 +/- 35 to 286 +/- 63 dynes.s.cm-5.m-2 (p < 0.05), and despite this increase in right ventricular afterload, no detrimental effect in RVEF (36 +/- 11 to 36 +/- 10%) or in RVEDVI (116 +/- 30 to 127 +/- 40 ml.m-2) was observed. A Frank-Starling relationship for the right ventricle was constructed by plotting an index of ventricular performance (RVSWI) against an index of ventricular preload (RVEDVI). A significant upward shift to the right of the relationship was observed during norepinephrine infusion. CONCLUSION: It was concluded that norepinephrine exerted a favourable effect on right ventricular function.     

Effects of in vivo cocaine administration on human platelet aggregation

Tc-99m-DTPA captopril scintigraphy was performed in a patient with suspected renovascular hypertension. Markedly impaired right renal function (Glomerular filtration rate (GFR) values for the right kidney = 14 ml/min, left kidney = 79 ml/min) was detected in the initial captopril study. Only lower pole activity of the right kidney was observed during the whole study. Since prior ultrasonographic examinations have shown bilateral normal kidney parenchyma, branch stenosis of the right upper pole was suspected. Besides significant function improvement in the following baseline study (GFR values for the right kidney = 59 ml/min, left kidney = 79 ml/min), the right kidney, this time normally shaped, was visibly higher positioned. Because of the possibility of mobile kidney and/or branch stenosis, the patient underwent selective renal angiography. A long pediculed right kidney without renal artery stenosis was found. The final diagnosis was essential hypertension. Kidney position anomalies could influence the reliability of the captopril scintigraphy, particularly when a theoretical kidney depth formula is employed for the attenuation correction.