Gallbladder dyskinesia in acalculous biliary colic

AIMS: To test the hypotheses that: 1) postprandial gallbladder emptying might be abnormal in patients with acalculous biliary colic; and 2) that hymecromone, a drug that increases bile flow and relaxes biliary muscle might improve symptoms. METHODS: Twenty-four women were studied. Twelve patients presented recurrent biliary type of pain in the absence of gallstones, and persistence of contrast in the gallbladder, 24 hours after an oral cholecystogram, suggesting cholesterolosis. Twelve healthy volunteers used as controls had no symptoms and the gallbladder was not visible the day after an oral cholecystogram. Gallbladder emptying induced by an oral meal was studied with ultrasound in both groups before and after the administration of hymecromone. RESULTS: Gallbladder volumes were similar in both groups (23 +/- 10 ml vs. 31 +/- 11 ml; NS). Gallbladder emptying in the control group was simple exponential (R2 = 0.948 +/- 0.059) with a rate of 32 +/- 16 minutes. Gallbladder emptying was bimodal in patients. Gallbladder volume increased to 120% in the first 10 minutes, to empty exponentially thereafter (R2 = 0.964 +/- 0.040. Rate: 29 +/- 22 minutes). This resulted in a marked reduction in gallbladder volume emptied at 40 minutes when compared to controls (30% +/- 27% vs. 54% +/- 14%; p = 0.012). Pretreatment of controls with hymecromone induced an emptying pattern similar to that of patients. In patients, emptying after hymecromone did not change but symptoms were improved. CONCLUSIONS: An abnormal emptying pattern of the gallbladder was identified in patients with acalculous biliary colic, and hymecromone was partly effective to reduce pain, despite a minor effect on gallbladder emptying pattern.     

Natural fermentation of lentils Influence of time, temperature and flour concentration on the kinetics of thiamin, riboflavin and niacin

Lentils (Lens culinaris, var. vulgaris cultivar Magda-20) were naturally fermented for 96 h at different lentil flour concentrations (79, 150 and 221 g/l) and temperatures (28, 35 and 42°C). During fermentation, samples were taken at 24-h intervals and the changes in thiamin (vitamin B₁), riboflavin (vitamin B₂) and total and available niacin (vitamin B₃) were investigated. Preparation of the lentil flour suspension to be fermented (i.e. the process of mixing the flour and sterilized tap water) caused an increase of the available niacin content in all batches, while changes in thiamin and riboflavin content were related to the conditions in which the preparation of the suspensions was carried out. The whole natural fermentation process (from the raw state to after 96 h of fermentation), either did not affect or produced a slight decrease in the thiamin content of lentils. In contrast, riboflavin, available niacin and total niacin contents increased throughout the 96 h period, which ended with a 35?–?82% increase of riboflavin, a 24?–?91% increase of available niacin and a 20?–?58% increase of total niacin. The temperature during the fermentation procedure had significant effect on the levels of thiamin and riboflavin in fermented lentils. To obtain lentil flours with an improved amount of riboflavin and available niacin with a minimum loss of thiamin, the natural fermentation of lentils should be carried out for 96 h at 42°C and with a lentil flour concentration of 221 g/l.     

Validation of the medical expert system PNEUMON-IA.

The present study validates the expert system PNEUMON-IA. The aim of PNEUMON-IA is assessing the etiology of community-acquired pneumonias from clinical, radiological, and laboratory data obtained at the onset of the disease. Validation was performed using data from medical records of 76 patients with proven clinical diagnosis of pneumonia. The etiological diagnoses provided by PNEUMON-IA were compared to those established by five specialists unrelated to the development of the expert system. For each etiological possibility, both PNEUMON-IA and the experts provided a causal possibility, expressed as a linguistic label (i.e., "almost impossible"). Linguistic labels were then converted to numeric values. In the majority of cases, an etiological diagnosis was unavailable to be used as a gold standard. To overcome this limitation, distances between arrays of etiological possibilities given by specialists and by PNEUMON-IA were considered as an agreement measure between diagnoses. Cluster analysis based on those distances was used to classify PNEUMON-IA among experts. Results showed the same differences between specialists and PNEUMON-IA as among the specialists themselves. The method used to validate PNEUMON-IA could prove useful to assess the performance of expert systems in fields where no gold standard is available.     

DTT functionalization of Ag particles for conducting adhesives

We have studied the influence of the organic molecule DL-Dithiothreitol on the properties of isotropic conductive adhesives for application in microelectronics. The Ag fillers were prepared from commercial micro flakes or submicron particles from waste jewelry. The results show that coating of the Ag recycled fillers with thiol avoided the agglomeration of the particles improving the dispersion and the electrical and mechanical properties. By comparing the samples, the better properties were obtained from adhesives with recycled Ag particles relative to the ones formulated with commercial Ag flakes and improvement can be attributed to the absence of the lubricant layer and smaller size of the particles produced from recycled silver.     

Size-shape determination of nonspherical particles in suspension by means of full and depolarized static light scattering

Full and depolarized static light-scattering (LS) experiments have been carried out to characterize the size and shape of colloidal suspensions. Results have been compared with theoretical predictions following the extended-boundary-condition method (T-matrix) formalism for scattering by nonspherical particles. Theory-to-experiment data fitting has yielded size-shape data that compare well with electron-microscopy determinations. Depolarized light-scattering has been found to be an especially useful tool to use to find the correct geometrical parameters of the suspended particles. Size (though not shape) is also correctly fitted through full LS experiments.     

Flash-lamp-excited self-injection-seeded Q-switched Ti:Al(2)O(3) laser oscillator

A self-injection-seeded, flash-lamp-excited, Q-switched laser oscillator is presented. The laser comprises two resonators that are operated sequentially. The first resonator, which includes all the high insertion loss, damage prone, wavelength tuning, and line-narrowing components, is used to generate the seed signal. The second resonator is a low-loss, Q-switched resonator whose output wavelength and line width are controlled by the seed signal. Output pulses of energy as high as 325 mJ have been obtained that are tunable over a range of the order of 90 nm and with a bandwidth of the order of 0.05 nm.     

A Bayesian network for burr detection in the drilling process

One of the most important processes in the aeronautical sector is drilling. The main problem associated with drilling is burr. There is a tolerance level for this burr and it cannot exceed 127 microns, which would provoke structural damage and other problems. Currently, the burr elimination task is carried out visually and manually with the aim of guaranteeing quality in the process. However, it is an expensive procedure and needs to be replaced by a motorized system capable of automatically detecting in which holes the burr exceeds the permitted level and has to be eliminated or reduced. The paper presents a burr prediction model for high speed drilling in dry conditions on aluminium (Al 7075-T6), based on a Bayesian network learned from a set of experiments based on parameters taken from the internal signal of the machine and parameters from the condition process. The paper shows the efficiency and validity of the model in the prediction of the apparition of burr during the drilling and compares the results with other data-mining techniques.     

Similarity in dense gas-solid fluidized bed, influence of the distributor and the air-plenum

Similitude parameters that govern the dynamics of dense gas-fluidized beds in possible interaction with the air-supply system (distributor and plenum) are found by nondimensionalizing both differential equations that rule the bed dynamics and the coupling with the upstream fluid inlet conditions. In addition to classical dimensionless groups, two new parameters θ_p and θ_d are evidenced. It is shown that their match, along with the other numbers, is required to ensure dynamic similarity for scaled systems. Their influence on the bed dynamics is also investigated and we propose (θ_p,θ_d) maps that illustrate the existence of a coupling zone with an associated frequency modification.     

Failure of last-stage turbine blades in a geothermal power plant

This paper presents an investigation into causes of failure of geothermal steam turbine blades. Several L-0 blades of geothermal steam turbines of 110 MW capacity suffered failures, causing forced outages of the turbines. To assess the causes of failure, the natural frequencies of the blades installed on the rotor were measured in the laboratory. The measured frequencies were compared with the natural frequencies calculated through a finite-element analysis (FEA) of the blade. The FEA was also used to calculate the vibratory stresses on the blade numerically. Also, the investigation analyzed the operational data and the history of the blade failures on several rotors of different units from the same system. The results of previous repairs were reviewed, and metallurgical investigations were conducted to identify the mechanical and metallurgical modes of failure. The results of the investigation showed that the fracture of two blades was attributed to installation and manufacturing errors and aggravated by general deterioration of the blades. The deterioration was caused by the erosion and corrosion process that resulted from moisture condensation in the steam.     

Investigation of the mechanical behaviour of multi-phase TRIP steels using finite element methods

In recent years, the development of high-strength steels such as multi-phase TRIP (transformation-induced plasticity)-aided steels have shown great promise due to their excellent combination of high strength and ductility, which allows for the use of thinner car frame components and subsequently weight reduction. The TRIP effect, characterized by the phenomenon known as strain-induced martensitic transformation (SIMT), enhances the work hardenability of such steels as the austenite phase transforms to the much harder martensite phase during plastic straining. However, various factors exist which affect the mechanical behaviour of TRIP steels. This study will aim, through the use of finite element models, to investigate the role and influence of each of these factors on the TRIP effect in multi-phase TRIP steels. These factors include the rate at which the martensitic transformation proceeds, the state of stress to which the material is subjected to and the interaction between the surrounding matrix and embedded retained austenite islands in multi-phase TRIP steels. Investigation of these factors will provide further insight on each of their contributions to the TRIP effect in order to exploit the potential benefits offered by these steels.