Intercritical annealing to achieve a positive strain-rate sensitivity of mechanical properties and suppression of macroscopic plastic instabilities in multi-phase medium-Mn steels.

This study investigates the high strain-rate tensile properties of a cold-rolled medium-Mn steel (Fe-12Mn-3Al-0.05C % in mass fraction) designed to have a multi-phase microstructure and positive strain-rate sensitivity. At the intercritical annealing temperature of 585 °C, increasing the annealing time from 0.5 h to 8 h increased the phase volume fraction of ultrafine-grained (UFG) austenite from 2% to 35% by reversion. The remainder of the microstructure was composed of UFG ferrite and recovered α'-martensite (the latter resembles the cold-rolled state). Servo hydraulic tension testing and Kolsky-bar tension testing were used to measure the tensile properties from quasi-static strain rates to dynamic strain rates ( ε ˙ = 10 - 4 s - 1 to ε ˙ = 10 3 s - 1 ). The strain-rate sensitivities of the yield strength (YS) and ultimate tensile strength (UTS) were positive for both annealing times. Tensile properties and all non-contact imaging modalities (infrared imaging and digital image correlation) indicated an advantageous suppression of Lüders bands and Portevin Le Chatelier (PLC) bands (a critical challenge in multi-phase medium-Mn steel design) due to the unique combination of microstructural constituents and overall composition. Fracture surfaces of specimens annealed for 0.5 h showed some instances of localized cleavage fracture (approximately 30 µm wide areas and lath-like ridges). Specimens annealed for 8 h maintained a greater product of strength and elongation by at least 2.5 GPa % (on average for each strain rate). The relevant processing-structure-property relationships are discussed in the context of recommendations for design strategies concerning multi-phase steels such that homogeneous deformation behavior and positive strain-rate sensitivities can be achieved.

Donor site morbidity after microvascular medial femoral condylar flap procurement for facial reconstruction.

The medial femoral condyle (MFC) flap is considered an ideal graft for bone reconstructions. This study was performed to evaluate donor site knee joint function and scar appearance after MFC flap procurement. Adult patients who had undergone facial reconstruction with an MFC flap between March 2011 and March 2017 at the University Hospital Salzburg were enrolled. Knee function was assessed postoperatively using two validated orthopaedic scores: Tegner Lysholm Knee Scoring Scale (TL) and Knee Society Score (KSS); both range from 0 to 100 (100 being no impairment). Scars were evaluated using the Patient and Observer Scar Assessment Scale (POSAS) (range 6-60). Thirty-eight patients were enrolled. The average postoperative TL score was 95.68 (range 66-100). The mean KSS clinical examination and function scores were 96.8 (range 58-100) and 97.11 (range 60-100), respectively. Flap type (osteocutaneous vs. non-osteocutaneous) did not correlate with TL or KSS scores. KSS and TL scores showed no association with vascular pedicle length or transplant volume. The average POSAS patient and observer scores were 6.84 and 15.24, respectively. POSAS observer scores were significantly higher for osteocutaneous flaps than for non-osteocutaneous flaps. The MFC flap causes minimal donor site morbidity. No knee joint instability or range of motion limitation was found. Postoperative TL and KSS scores indicated excellent knee function.

Experimental and numerical study of mechanical properties of multi-phase medium-Mn TWIP-TRIP steel: influences of strain rate and phase constituents.

In the current work we investigate the room temperature tensile properties of a medium-Mn twinning- and transformation-induced plasticity (TWIP-TRIP) steel from quasi-static to low-dynamic strain rates ( ε ˙ = 10 - 4 s - 1 to ε ˙ = 10 2 s - 1 ). The multi-phase microstructure consists of coarse-grained recovered α' -martensite (inherited from the cold-rolled microstructure), multiple morphologies of ultrafine-grained (UFG) austenite (equiaxed, rod-like and plate-like), and equiaxed UFG ferrite. The multi-phase material exhibits a positive strain-rate sensitivity for yield and ultimate tensile strengths. Thermal imaging and digital image correlation allow for in situ measurements of temperature and local strain in the gauge length during tensile testing, but Lüders bands and Portevin Le Chatelier bands are not observed. A finite-element model uses empirical evidence from electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM), plus constitutive equations to dissect the microstructural influences of grain size, dislocation density and TWIP-TRIP driving forces on tensile properties. Calibration of tensile properties not only captures the strain rate sensitivity of the multi-phase TWIP-TRIP steel, but also provides opportunity for a complete parametric analysis by changing one variable at a time (phase fraction, grain size, strain-induced twin fraction and strain-induced ε-martensite fraction). An equivalent set of high-rate mechanical properties can be matched by changing either the austenite phase fraction or the ratio of twinning vs. transformation to ε-martensite. This experimental-computational framework enables the prediction of mechanical properties in multi-phase steels beyond the experimental regime by tuning variables that are relevant to the alloy design process.

Validated method for the determination of hydroquinone in human urine by high-performance liquid chromatography-coulometric-array detection.

The paper describes the computer aided method development and validation for the determination of hydroquinone in human urine from a clinical study on renal excretion of hydroquinone metabolites and the release of free hydroquinone in the urinary tract in order to evaluate the proposed urine disinfecting concept. The presented method uses high-performance liquid chromatography on reversed-phase material with a polar endcapping (Aqua-C18, 250x4.6 mm). Selective and sensitive determination (LOQ= 12.5 ng on-column) of the target compound was achieved by electrochemical array detection (CoulArray). Gradient and parameter optimization were supported by DryLab software in order to minimize efforts of the expensive and time-consuming method development. Specificity and selectivity were carried out by separation experiments involving the prodrug arbutin and the metabolites hydroquinone, hydroquinone glucuronide, and hydroquinone sulfate, respectively. Hydroquinone glucuronide reference standard was obtained from in vitro glucuronidation in a rat liver microsomes assay. The method was validated according to the criteria for validation of pharmaceutical bioanalytical methods as drafted by the US Department of Health and Human Services, 1998.

Reconstruction of the extensor mechanism after proximal tibia endoprosthetic replacement.

The proximal tibia is a difficult area in which to perform a wide resection of a bone tumor. This difficulty is due to the intimate relationship of tumor in this location to the nerves and blood vessels of the leg, inadequate soft tissue coverage after endoprosthetic reconstruction, and the need to reconstruct the extensor mechanism. Competence of the extensor mechanism is the major determinant of functional outcome of these patients. Between 1980 and 1997, 55 patients underwent proximal tibia resection with endoprosthetic reconstruction for a variety of malignant and benign-aggressive tumors. Reconstruction of the extensor mechanism included reattachment of the patellar tendon to the prosthesis with a Dacron tape, reinforcement with autologous bone-graft, and attachment of an overlying gastrocnemius flap. All patients were followed for a minimum of 2 years; 6 patients (11%) had a transient peroneal nerve palsy, 4 patients (7.2%) had a fasciocutaneous flap necrosis, and 2 patients (3.6%) had a deep wound infection. Full extension to extension lag of 20 degrees was achieved in 44 patients, and 8 patients required secondary reinforcement of the patellar tendon. Function was estimated to be good to excellent in 48 patients (87%). Reattachment of the patellar tendon to the prosthesis and reinforcement with an autologous bone-graft and a gastrocnemius flap are reliable means to restore extension after proximal tibia endoprosthetic reconstruction.

Palliative forequarter amputation for metastatic carcinoma to the shoulder girdle region: indications, preoperative evaluation, surgical technique, and results.

BACKGROUND AND OBJECTIVES: Uncontrolled metastatic carcinoma of the shoulder girdle is a difficult oncologic problem. This study reviews our experience with palliative forequarter amputation with emphasis on patient selection criteria, preoperative radiologic assessment, surgical technique, epineural postoperative analgesia, and clinical outcome. METHODS: Eight patients who underwent palliative forequarter amputation for metastatic carcinoma between 1980 and 1999 were analyzed retrospectively. Diagnoses included breast carcinoma (n = 3), squamous cell carcinoma (n = 2), hypernephroma (n = 2), and carcinoma of unknown origin (n = 1). All patients presented with severe, intractable pain and a useless extremity. Venography demonstrated obliteration of the axillary vein in each of the patients in whom this procedure was performed. Exploration of the brachial plexus confirmed tumor encasement and unresectability in all patients. Epineural catheters for bupivacaine infusion were placed for postoperative pain control. RESULTS: All patients experienced dramatic pain relief and improved mobility and overall function. Life-threatening hemorrhage and sepsis were alleviated. There were no instances of phantom limb pain or adverse psychological reactions, and no complications related to epineural analgesia. CONCLUSIONS: Palliative forequarter amputation is relatively safe and reliable and provides effective pain relief for selected patients with unresectable metastatic carcinoma to the axilla and bony shoulder girdle in whom radiotherapy and/or chemotherapy has not been effective. The triad of pain, motor loss, and an obliterated axillary vein is indicative of brachial plexus infiltration and unresectability.

Giant cell tumor of the hand: superior results with curettage, cryosurgery, and cementation.

At our institution giant cell tumors arising in all locations are treated with curettage, cryosurgery, and cementation to avoid resection or amputation, increase local tumor control over curettage alone, and avoid the morbidity associated with immobilization. We report the oncologic and functional results of 3 patients with giant cell tumors arising from the tubular bones of the hand who were treated in this manner. At a mean follow-up period of 54 months there were no local recurrences. No patient complained of pain. Digital range of motion and grip strength were within normal limits for all 3 patients. All patients returned to their previous occupational and recreational activities. One instance of minor wound necrosis was successfully treated conservatively. There were no other complications (fractures, infections, neuropraxias, or vascular damage). Curettage, cryosurgery, and cementation performed by experienced surgeons appears to be a safe, effective, and reliable method for treating selected giant cell tumors of the hand.

Identification of quercetin glucuronides in human plasma by high-performance liquid chromatography-tandem mass spectrometry.

After intake of food or herbal medicinal products containing quercetin glycosides, the systemic availability of the genuine glycoside, as well as the systemic occurrence of the aglycone or conjugates of this polyphenol has been a matter of dispute. Consequently, we designed this study to develop a reliable method for determination of quercetin and its metabolites. Following consumption of fried onions five different glucuronides of quercetin could be identified in human plasma samples by means of HPLC-UV-MS/MS. Selective determination of the target compounds was achieved by simultaneous UV (254 nm) and MS/MS detection with selected reaction monitoring experiments using positive mode electrospray ionisation. In contrast, neither the free flavonol nor the genuine glycoside could be detected in plasma. Identification of the quercetin glucuronides detected in vivo was confirmed by comparison with authentic reference compounds synthesised enzymatically using glucuronyl transferase from rabbit liver.

Pharmacokinetics and bioavailability of quercetin glycosides in humans.

Due to its potentially beneficial impact on human health, the polyphenol quercetin has come into the focus of medicinal interest. However, data on the bioavailability of quercetin after oral intake are scarce and contradictory. Previous investigations indicate that the disposition of quercetin may depend on the sugar moiety of the glycoside or the plant matrix. To determine the influence of the sugar moiety or matrix on the absorption of quercetin, two isolated quercetin glycosides and two plant extracts were administered to 12 healthy volunteers in a four-way crossover study. Each subject received an onion supplement or quercetin-4'-O-glucoside (both equivalent to 100 mg quercetin), as well as quercetin-3-O-rutinoside and buckwheat tea (both equivalent to 200 mg quercetin). Samples were analyzed by HPLC with a 12-channel coulometric array detector. In human plasma, only quercetin glucuronides, but no free quercetin, could be detected. There was no significant difference in the bioavailability and pharmacokinetic parameters between the onion supplement and quercetin-4'-O-glucoside. Peak plasma concentrations were 2.3 +/- 1.5 microg x mL(-1) and 2.1 +/- 1.6 microg x mL(-1) (mean +/- SD) and were reached after 0.7 +/- 0.2 hours and 0.7 +/- 0.3 hours, respectively. After administration of buckwheat tea and rutin, however, peak plasma levels were--despite the higher dose-only 0.6 +/- 0.7 microg x mL(-1) and 0.3 +/- 0.3 microg x mL(-1), respectively. Peak concentrations were reached 4.3 +/- 1.8 hours after administration of buckwheat tea and 7.0 +/- 2.9 hours after ingestion of rutin. The terminal elimination half-life was about 11 hours for all treatments. Thus, the disposition of quercetin in humans primarily depends on the sugar moiety. To a minor extent, the plant matrix influences both the rate and extent of absorption in the case of buckwheat tea administration compared with the isolated compound. The site of absorption seems to be different for quercetin-4'-O-glucoside and quercetin-3-O-rutinoside. The significance of specific carriers on the absorption of quercetin glycosides, as well as specific intestinal beta-glucosidases, needs to be further evaluated.

Intraadrenal steroid metabolism in the guinea pig: guinea pig adrenal microsomes metabolize androstenedione in a manner distinct from liver microsomes.

Several immunochemical homologs of hepatic cytochromes P450 (CYPs) capable of steroid catabolism have been identified in the guinea pig adrenal cortex. Their predominance in males suggests a role in sex-differentiated metabolism of androgens. Therefore, we examined the ability of microsomes from male guinea pig adrenals and liver to metabolize androstenedione. Microsomes were incubated in the presence of radiolabeled steroids, the products of the reaction extracted, separated by TLC, and visualized by autoradiography. Metabolites were identified by comigration with commercially available standards in several solvent systems, in one and two dimensional TLC. Microsomes from both tissues metabolized androstenedione. However, the products formed differed markedly in the two tissues. Liver microsomes formed one major metabolite, testosterone. It represented 85% of the metabolized androstenedione. 6 beta-Hydroxylated androstenedione and testosterone each comprised 3-4% of the liver metabolites. In addition, at least 10 other products were formed, but taken together they constituted less than 8% of the metabolized androdostenedione. Adrenal microsomes, on the other hand, produced several major metabolites: 16 alpha-, 16 beta-, and 6 beta-hydroxy-androstenedione, plus one unidentified product constituted 93% of the metabolized androstenedione. 16 alpha-Hydroxylation of androstenedione was 60 fold, 16 beta-hydroxylation 12 fold, and 6 beta-hydroxylation 2.5 fold greater in adrenal than in liver microsomes. The unidentified product, which was the least polar, was formed exclusively by adrenal microsomes. The hydroxylation reactions performed by adrenal tissue are consistent with the presence in adrenal microsomes of immunochemical homologues of members of the CYP1A, 2B, 2C and 3A families which have known steroid hydroxylation functions in liver. The Kms of the formation of 16 alpha-, 16 beta- and 6 beta-hydroxyandrostenedione by adrenal microsomes are in the range reported for steroid hydroxylation reactions in rat liver tissue. Their distinct values suggest that these hydroxylation steps are performed by different CYPs. However, assignment of site-specific steroid hydroxylation reactions to individual hepatic CYP homologs in the adrenal requires further investigation and is being pursued using combined techniques of biochemistry and molecular biology.

The PI3-kinase serine kinase phosphorylates its p85 subunit and IRS-1 in PI3-kinase/IRS-1 complexes.

Insulin receptor tyrosine kinase activity accounts for tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), but the serine kinase(s) responsible for serine phosphorylation of IRS-1 is(are) unknown. In vitro kinase assays performed on PI3-kinase and IRS-1 immunoprecipitates demonstrated insulin-dependent serine phosphorylation of IRS-1. IRS-1 was associated with both insulin-dependent and independent serine kinases. Only the insulin-dependent serine kinase preferred Mn2+ over Mg2+ and was recovered from cell lysates containing dithiothreitol. In complexes of tyrosine phosphorylated recombinant IRS-1 and PI3-kinase, phosphorylation of IRS-1 was associated with decreased phosphorylation of the p85 subunit of PI3-kinase. These results are consistent with PI3-kinase being responsible for insulin-dependent serine phosphorylation of IRS-1 and suggest that this phosphorylation reaction may affect functions of both IRS-1 and the PI3-kinase.

Picosecond nonlinear optical response of a Cu:silica nanocluster composite.

We describe the picosecond nonlinear optical response of a metal-dielectric composite made by implanting Cu ions in fused silica. The implanted Cu ions aggregate during implantation to form nanometer-diameter clusters in a dense, thin (~150 nm) layer just beneath the surface of the substrate. The third-order susceptibility X((3)) has an electronic component with a magnitude of the order of 10(-8) esu and is enhanced for laser wavelengths near the surface plasmon resonance of the copper colloids.

[The distribution of microorganisms in household kitchens. I. Problems, experiments, results]. / Untersuchungen zur Keimverbreitung in Haushaltküchen. I. Mitteilung: Problemstellung, Versuche, Ergebnisse.

Epidemiological investigations have demonstrated that insufficient hygiene in households results in increasing health hazards. In order to be able to recommend ways to disrupt infection chains it was necessary to explore the most important pathways of cross-contamination. Housewives without special training were instructed to prepare a complete meal, in the kitchen of a modern, vacant apartment. Among the raw products provided was minced meat, contaminated with Sarcinae (unbeknown to the housewives) in a quantitative manner. When cooking and cleaning procedures were completed we analysed household utensils and surfaces by Rodac impressions and swabs. The test organisms could be detected on all inspected surfaces and on the dining-table with albeit different frequencies. The following locations showed an especially high degree of cross-contamination: a) working-surfaces, especially boards of wood and plastics. b) cutting-machines, c) kitchen-machines. These results agree with literature data. By careful disinfection, i.e. by application of a 0.5% solution of hypochlorite, the contaminations could be removed. We assessed this when arranging the kitchen for the next test. Since it is impossible to practise disinfection procedures in a household kitchen on the same scale as in an operating room, we tried to achieve at least a limited disinfection by household cleansers with germicidal properties. In our opinion a minimum reduction of five log stages, demanded in the medical area, can not be achieved in a household kitchen and indeed it is not necessary. A reduction of the microbial counts to 10% of the original value would already be useful, as toxic levels of microbial counts will be reached later especially when there is simultaneous refrigeration. Correct dosage proved to be one of the main practical problems because a discrepancy exists between the low concentration of tensids, necessary for cleaning, and the relatively high dose necessary for germ-killing compounds. Diluted DOMESTOS proved to be a cleaning agent and germicide, but was, however, blamed for chlorine odour, especially when diluted with warm water. A greater acceptance level was reached with a peroxide-containing cleanser, which, however, was not sufficiently germicidal, when applied in diluted form. The concentrated formulation was more effective in everyday experience, but for this housewives had to wear rubber gloves. This was reported to be complicated and uncomfortable, and indeed the search for better formulations must be continued. (In communication II comparisons with the bibliography and hygienic consequences will be published.)

[The distribution of microorganisms in household kitchens. II. Evaluation of results and hygienic inferences]. / Untersuchungen zur Keimverbreitung in Haushaltküchen II. Mitteilung: Beurteilung der Resultate und hygienische Schlussfolgerungen.

The very high morbidity rates of Enteritis infectiosa diseases demand improved prophylactic measures. An important indication of the source of these illnesses is the fact that infections in private households are about three times more frequent than in canteens. Indeed, the rise in morbidity is undoubtedly caused by inadequate treatment of raw products, of meal rests and by insufficient heating processes. Furthermore, in household kitchens no efforts are made to interrupt infection chains, and disinfections are considered as superfluous and housewives are content if their kitchens appear to be clean. The aim of our study performed in a normal household kitchen, was to investigate cross-contamination caused by pathogens, introduced into the kitchen from outdoors. A further aim was to establish the main sources of contamination in order to be able to recommend practical disinfection procedures. The main fields of contamination discovered when 55 meals prepared were: a) working surfaces (including boards of wood and plastics) b) kitchen- and cutting-machines. The amount of test organisms (Sarcinae), introduced into the kitchen (unbeknown to the housewives) by experimentally contaminated minced meat was only reduced by common cleaning procedures, in sofar as nearly half of the original contaminations could be demonstrated to be still present. However, when the normal cleanser was replaced by one containing hypochlorite, and with retention of the same working routines, about 90% bacteriologically clean surfaces were determined. In this way it could be demonstrated that infection chains can be interrupted. It is, however, not correct to compare the efficiency of these procedures with the efficiency of disinfection, according to the Federal Infectious Diseases Act (Bundesseuchengesetz). On practical application of these experiences it must be borne in mind that housewives should not be forced to apply medical disinfection procedures: indeed, traditional and practised cleaning methods should be retained, as far as possible. We recommend therefore that manufacturers supply household cleansers with an anti-bacterial additive, after its application in the kitchens working surfaces and machines are bacteriologically clean. Additionally housewives should be appropriately informed about the necessity of these manipulations. We consider minimization of toxicity and a thorough environmental compatibility of formulations to be self-evident.

Echocardiographic observations of calcium in operatively excised stenotic aortic valves.

Qualitative and quantitative 2-dimensional (2-D) echocardiographic methods were developed to define the anatomic and physiologic significance of valvular calcium in aortic stenosis (AS). Qualitative methods assigned etiologic diagnoses by matching patterns of calcium with anatomic criteria. Quantitative techniques measured echodensities from superimposed short-axis views of calcium. Fifty-five pathologic specimens procured from surgery were photographed and radiographed. Etiologic diagnoses were assigned from gross examination and radiodensities were planimetered. Echocardiographic and anatomic diagnoses were compared. Sensitivities for diagnosing the most common etiologies, congenitally bicuspid and degenerative, were 58% and 100% and specificities were 100% and 76%. Calcium tended to be heaviest in congenitally diseased valves and lightest in those with degenerative disease (p less than 0.2) and showed propensity for the right cusp in all etiologies except for those with degenerative disease. Correlation of echodensities to radiodensities was 0.82. The relation of calcific echodensities to orifice area was curvilinear; beyond a level of calcium, further deposits did not reduce the orifice more. A systematic echocardiographic examination of calcium in stenotic aortic valves can give a correct etiologic diagnosis in most patients and identify the severely narrowed orifice.

[Occurrence of enteritis-causing agents in private households--a pilot study]. / Untersuchungen über das Vorkommen von Enteritis-Erregern im Haushalt--eine Pilotstudie.

The increasing occurrence of infectious enteritis caused us to perform a prospective, epidemiological pilotstudy in households, in order to receive informations about the practicability of such a project and the bacteriology of food prepared at home as well. 10 families were asked to gather samples of all foodstuffs consumed during the day in separate containers and to keep them frozen at - 20 degrees C until collected by us once a week. Thus we received 4.683 samples within a 6-months-period. In the laboratory those samples were mixed following Table 2 and examined concerning the occurrence of enteropathogenic bacteria. Additionally we carried out an investigation of kitchensurfaces and -utensils by means of "Rodac"-plates. The evaluation of the food-samples showed no growth of salmonella, shigella, yersinia or campylobacter; however, in 267 samples were found staphylococci, in 191 enterococci, in 388 enterobacteria, in 28 aerobic sporeformers and in 144 fungi. Mainly sausage- and meatproducts appeared to be contaminated by staphylococci, also enterococci and enterobacteria (Fig. 1); other groceries were colonized by these microorganisms only to a minor degree. Fungi and aerobic sporeformers were isolated primarily in salads, bakery- and milkproducts (Fig. 2). Though some of the foodstuffs contained up to 10(5) pathogenes/g (Fig. 5), no cases of gastroenteritis were observed within our families. In case of mishandling (e.g. storage of food in refrigerators with temperatures above 4 degrees C) the development of foodborne enteritis has to be taken into account. The kitchens' examination showed a relatively high degree of contamination with pathogenic resp. potentially pathogenic organisms, represented in Fig. 7 by data obtained from different objects of investigation (surfaces, sinks and cloths).

Recent trends in the management of life-threatening ventricular arrhythmias.

An edited summary of an Interdepartmental Conference arranged by the Department of Medicine, UCLA School of Medicine, Los Angeles. William M. Pardridge, MD, Associate Professor of Medicine, is Director of Conferences. This study was supported in part by grants from the Public Health Service; the National Institutes of Health (HL-23970, 1978-1981); the Medical Research Service of the Veterans Administration, and the American Heart Association, the Greater Los Angeles Affiliate.

Coronary artery bypass in hereditary factor XI deficiency.

Hereditary factor XI deficiency is a disorder of coagulation that has been associated with postoperative bleeding. Because cardiopulmonary bypass itself induces transient abnormalities in hemostasis, the patient with factor XI deficiency could be at increased risk for bleeding after cardiac surgical procedures. We report the successful management of a 61-year-old man with hereditary factor XI deficiency who had coronary artery bypass. Treatment with low-dose aspirin, begun 24 hours postoperatively for graft patency, was well tolerated. Once recognized and aggressively treated, factor XI deficiency does not appear to be a contraindication to potentially life-saving procedures like coronary revascularization.