Measuring the stress field around an evolving crack in tensile deformed Mg AZ31 using three-dimensional X-ray diffraction

The stress field around a notch in a coarse grained Mg AZ31 sample has been measured under tensile load using the individual grains as probes in an in situ high energy synchrotron diffraction experiment. The experimental set-up, a variant of three-dimensional X-ray diffraction microscopy, allows the position, orientation and full stress tensor of each illuminated grain to be determined and, hence, enables the study of evolving stress fields in coarse grained materials with a spatial resolution equal to the grain size. Grain resolved information like this is vital for understanding what happens when the traditional continuum mechanics approach breaks down and fracture is governed by local heterogeneities (e.g. phase or stress differences) between grains. As a first approximation the results obtained were averaged through the thickness of the sample and compared with an elastic–plastic continuum finite element simulation. It was found that a full three-dimensional simulation was required to account for the measured transition from the overall plane stress case away from the notch to the essentially plane strain case observed near the notch tip. The measured and simulated stress contours were shown to be in good agreement except at the highest applied load, at which stress relaxation at the notch tip was observed in the experimental data. This stress relaxation is attributed to the initiation and propagation of a crack. Finally, it was demonstrated that the measured lattice rotations could be used as a qualitative measure of the shape and extent of the plastic deformation zone.     

Operability and Flexibility of a Milk Production Line

The operability and flexibility of an existing milk treatment process are investigated through flowsheet modelling and simulation method. From the flowsheet simulation, a process operating region is determined using incoming milk flow viscosity and heat exchanger pressure drop as characteristic parameters. The operability and flexibility of the nominal operating points are evaluated with a minimization of the process pasteurization and cooling temperatures through vertex enumeration method. The milk treatment process simulation and process analysis provide a quantitative analysis method for the development of a flexible process in dairy industrial applications. The established process operability and flexibility analysis framework and flowsheet simulation can be adapted to other liquid food productions.     

Gestalt descriptions embodiments and medical image interpretation

In this paper I will argue that medical specialists interpret and diagnose through technological mediations like X-ray and fMRI images, and by actualizing embodied skills tacitly they are determining the identity of objects in the perceptual field. The initial phase of human interpretation of visual objects takes place during the moments of visual perception before we are consciously aware of the perceived. What facilitate this innate ability to interpret are experiences, learning and training that become humanly embodied skills. These embodied skills are actualized during the moments of visual perception. My argument is that biology, society and instruments constitute unique individual ontologies influencing specialist readings of the technological output, in other words, putting limits on the “truth-to-nature” relation, which is so much sought for in science.     

POETS: Process-oriented event-driven transaction systems

We present a high-level enterprise system architecture that closely models the domain ontology of resource and information flows in enterprises. It is:Process-orientedformal, user-definable specifications for the expected exchange of resources (money, goods, and services), notably contracts, are represented explicitly in the system state to reflect expectations on future events;Event-drivenevents denote relevant information about real-world transactions, specifically the transfer of resources and information between economic agents, to which the system reacts by matching against its portfolio of running processes/contracts in real time;Declarativeuser defined reporting functions can be formulated as declarative functions on the system state, including the representations of residual contractual obligations.We introduce the architecture and demonstrate how analyses of the standard reporting requirements for companies—the income statement and the balance sheet—can be used to drive the design of events that need registering for such reporting purposes. We then illustrate how the multi-party obligations in trade contracts (sale, purchase), including pricing and VAT payments, can be represented as formal contract expressions that can be subjected to analysis.To the best of our knowledge this is the first architecture for enterprise resource accounting that demonstrably maps high-level process and information requirements directly to executable specifications.     

Genetic risks of in vitro fertilization

In-vitro fertilization (IVF) with embryo transfer is a well established therapy in infertility. With the increase of andrological problems as reasons for IVF the question of possible genetic risks is gaining additional attention. For the patients, the incidence of congenital malformations in their offspring resulting from IVF as well as the incidence of spontaneous abortions are of particular interest. In this review population genetic data of congenital malformations are compared to those found in IVF populations. On average, congenital malformations occur in 3% of all livebirths in an unselected population, whereas there were 1.5% newborns with congenital malformations reported in the IVF population. This is well within this basic background risk for congenital malformations. Bearing maternal age and especially careful follow-up of early pregnancies after IVF in mind, the rate of spontaneous abortions after IVF (21 to 27%) is also not significantly increased above the rate of 15% in the unselected general population. The introduction of microinvasive techniques into IVF has given the question of possible genetic risks for the offspring from IVF using these techniques, a great deal of topical interest. The range of indications of subzonal or intracytoplasmatic sperm injection (ICSI) includes andrological problems to a high degree which themselves could be the result of chromosomal anomalies or hereditary disorders. One example is the vas deferens aplasia in one form of CF mutations. Cytogenetic and clinical genetic evaluation should be recommended especially in cases of andrological or idiopathic sterility and infertility. Some examples of autosomal dominant syndromes in which clinical genetic evaluation and genetic counselling are advisable are listed in a summarizing table.     

Medium-term patency and anatomic changes after direct bronchial artery revascularization in lung and heart-lung transplantation with the internal thoracic artery conduit

OBJECTIVE: To examine the relationship of estrogen-induced changes in lipids and lipoproteins with alterations in the coagulation system. METHODS: Coagulation and lipid indices were measured in 31 postmenopausal women, ages 40-60 years, after a 3-month course of 0.625-mg conjugated equine estrogen. We analyzed changes in variables from baseline to 3 months using t tests for paired samples or the Wilcoxon matched-pairs signed-rank test. RESULTS: Unopposed estrogen replacement therapy produced statistically significant decreases in antithrombin-III antigen (P = .006) and activity (P = .001) and total protein S (P = .003) and a significant increase in protein C antigen (P = .017). C4b-binding protein also decreased significantly from baseline to 3 months (P < .001). Mean fibrinogen level decreased by 18.2 mg/dL, not a statistically significant change (P = .213). Estrogen produced the expected statistically significant changes in lipids and lipoproteins. Several correlations between changes in lipids and lipoproteins and coagulation indices were statistically significant. Protein C antigen and activity changes correlated directly with high-density lipoprotein cholesterol changes (r = .52, P < or = .005; r = .38, P < or = .05; respectively), and protein C antigen also correlated directly with increases in apoprotein A-I (r = .54, P < or = .005). Triglyceride changes correlated directly with changes in protein C antigen (r = .36, P < or = .05) and activity (r = .49, P < or = .005) and inversely with C4b-binding protein (r = -.58, P < or = .01). Apoprotein B was correlated with free protein S (r = .48, P < or = .01). CONCLUSIONS: Although several estrogen-induced changes may decrease atherosclerotic potential and hypercoagulability, others may promote coagulability. These divergent effects may be manipulated pharmacologically by other estrogen compounds or by the addition of various progestins.     

Increased sensitivity of the cough reflex in progressive systemic sclerosis patients with interstitial lung disease

Cough is a common presenting symptom of interstitial lung disease (ILD). The aim of this study was to examine the cough reflex in patients with progressive systemic sclerosis (PSS), with and without associated ILD. The cough reflex to inhalation of chloride deficient solutions and capsaicin was determined in patients with PSS with associated ILD (n=12), compared to patients with PSS without ILD (n=12). In addition, patients with a chronic dry cough (n=12) and healthy subjects (n=10) without cough were studied. Cough responses to inhalation of isotonic solutions containing 150, 75, 37.5 and 0 mM Cl- ions and of capsaicin (0.9-500 mM) were measured. PSS patients with ILD reported a significantly higher cough score than PSS patients without ILD (p<0.03). ILD patients coughed more than those without ILD to Cl- of 37.5 and 0 mM (19.1+/-5.0 vs 6.2+/-1.9 coughs x min(-1) (p<0.03), and 29.2+/-5.0 vs 14.1/-4.1 coughs x min(-1) (p<0.04), respectively). The log concentration of capsaicin causing two or five coughs was lower in PSS with ILD compared to PSS without ILD (0.74+/-0.15 mM vs 2.12+/-0.26 mM; p<0.002). Patients with chronic dry cough had a similar degree of response to low-chloride and capsaicin solutions as patients with PSS and ILD, whilst healthy controls had a similar degrees of response to PSS patients. There is an increased cough reflex in patients with interstitial lung disease, which may represent sensitization of airway sensory nerves. This may be the basis for the chronic dry cough in patients with interstitial lung disease.     

Structural requirements for PAK activation by Rac GTPases

The Rho family GTPases, Rac1 and Rac2, regulate a variety of cellular functions including cytoskeletal reorganization, the generation of reactive oxygen species, G1 cell cycle progression and, in concert with Ras, oncogenic transformation. Among the many putative protein targets identified for Rac (and/or Cdc42), the Ser/Thr kinase p21-activated kinase (PAK) is a prime candidate for mediating some of Rac's cellular effects. This report shows that Rac1 binds to and stimulates the kinase activity of PAK1 approximately 2- and 4-5-fold, respectively, better than Rac2. Mutational analysis was employed to determine the structural elements on Rac and PAK that are important for optimal binding and activation. The most notable difference between the highly homologous Rac isomers is the composition of their C-terminal polybasic domains. Mutation of these six basic residues in Rac1 to neutral amino acids dramatically decreased the ability of Rac1 to bind PAK1 and almost completely abolished its ability to stimulate PAK activity. Moreover, replacing the highly charged polybasic domain of Rac1 with the less charged domain of Rac2 (and vice versa) completely reversed the PAK binding/activation properties of the two Rac isomers. Thus, polybasic domain differences account for the disparate abilities of Rac1 and Rac2 to activate PAK. PAK proteins also contain a basic region, consisting of three contiguous lysine residues (Lys66-Lys67-Lys68), which lies outside of the previously identified Cdc42/Rac-binding domain. Mutation of these Lys residues to neutral residues decreased PAK binding to activated Rac1 and Rac2 (but not Cdc42) and greatly reduced PAK1 activation by Rac1, Rac2, and Cdc42 proteins in vivo. In contrast, mutation of lysines 66-68 to basic Arg residues did not decrease (and in some cases enhanced) the ability of Rac1, Rac2, and Cdc42 to bind and activate PAK1. Our studies suggest that the polybasic domain of Rac is a novel effector domain that may allow the two Rac isomers to activate different effector proteins. In addition, our results indicate that a basic region in PAK is required for PAK activation and that binding of Rac/Cdc42 to PAK is not sufficient for kinase activation.