Ultrasound evaluation of piglet diaphragm function before and after fatigue

Clinically, a noninvasive measure of diaphragm function is needed. The purpose of this study is to determine whether ultrasonography can be used to 1) quantify diaphragm function and 2) identify fatigue in a piglet model. Five piglets were anesthetized with pentobarbital sodium and halothane and studied during the following conditions: 1) baseline (spontaneous breathing); 2) baseline + CO2 [inhaled CO2 to increase arterial PCO2 to 50-60 Torr (6.6-8 kPa)]; 3) fatigue + CO2 (fatigue induced with 30 min of phrenic nerve pacing); and 4) recovery + CO2 (recovery after 1 h of mechanical ventilation). Ultrasound measurements of the posterior diaphragm were made (inspiratory mean velocity) in the transverse plane. Images were obtained from the midline, just inferior to the xiphoid process, and perpendicular to the abdomen. M-mode measures were made of the right posterior hemidiaphragm in the plane just lateral to the inferior vena cava. Abdominal and esophageal pressures were measured and transdiaphragmatic pressure (Pdi) was calculated during spontaneous (Sp) and paced (Pace) breaths. Arterial blood gases were also measured. Pdi(Sp) and Pdi(Pace) during baseline + CO2 were 8 +/- 0.7 and 49 +/- 11 cmH2O, respectively, and decreased to 6 +/- 1.0 and 27 +/- 7 cmH2O, respectively, during fatigue + CO2. Mean inspiratory velocity also decreased from 13 +/- 2 to 8 +/- 1 cm/s during these conditions. All variables returned to baseline during recovery + CO2. Ultrasonography can be used to quantify diaphragm function and identify piglet diaphragm fatigue.     

Design and Analysis of Remote Center of Compliance Structures

Remote center‐of‐compliance devices were developed to facilitate insertion for assembly operations. An analysis using screw theory yields a more accurate model to better characterize the interesting properties of remote compliance. For design purposes, the remote center location and stiffnesses are presented as nondimensional ratios that are only functions of geometrical properties and Poisson's ratio. Important design results are (i) the high sensitivity of the center location and (ii) the inverse relationship between linear and angular lateral stiffnesses. © 2003 Wiley Periodicals, Inc.     

Intracranial arterial dolichoectasia in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder with a variety of cardiovascular manifestations. This study presents a group of patients with ADPKD who had intracranial arterial dolichoectasia. One hundred seventy-eight ADPKD patients were screened with magnetic resonance angiography, 40 ADPKD patients had conventional angiography, and 98 ADPKD patients underwent a brain autopsy. For comparison, 360 patients without ADPKD who had magnetic resonance angiography and conventional angiography or brain autopsy were also studied. The prevalence of asymptomatic intracranial arterial dolichoectasia was 2.2% (4 of 178), 2.5% (1 of 40), and 2.0% (2 of 98) in the three ADPKD groups, respectively. None of the patients without ADPKD had intracranial arterial dolichoectasia. In addition to the seven patients with asymptomatic disease, two ADPKD patients with vertebrobasilar dolichoectasia had posterior circulation ischemic symptoms. The mean age of the nine patients (five men and four women) was 56.6 yr (range, 41 to 67 yr). The posterior circulation was involved in five patients, the anterior circulation was involved in two patients, and both were involved in two patients. Arterial dissection was believed to have caused middle cerebral artery dolichoectasia in one patient, and intracranial arterial dissections were strongly suspected in two other patients. Six of the nine patients with intracranial arterial dolichoectasia had additional vascular manifestations of ADPKD. Some patients with ADPKD are at an increased risk of developing intracranial arterial dolichoectasia and dissections. Recognizing this association is important because (1) it may be a cause of stroke; (2) it may mimic a saccular aneurysm on radiographic studies; and (3) it suggests that the arteriopathy of ADPKD may be more generalized than previously believed.     

Phase Stability in the Mo-Ti-Zr-C System via Thermodynamic Modeling and Diffusion Multiple Validation

Alloys in the Mo-rich corner of the Mo-Ti-Zr-C system have found broad applications in non-oxidizing environments requiring structural integrity well beyond 1273 K (1000 °C). Alloys such as TZM (Mo-0.5Ti-0.08Zr-0.03C by weight %) and TZC (Mo-1.2Ti-0.3Zr-0.1C by weight) owe much of their high temperature strength and microstructural stability to MC and M₂C carbide phases. In turn, the stability of the respective carbides and the subsequent mechanical behavior of the alloys are strongly dependent on the alloying additions and thermal history. A CALPHAD-based thermodynamic modeling approach is employed to develop a quaternary thermodynamic database for the Mo-Ti-Zr-C system. The thermodynamic database thus developed is validated with diffusion multiple experiments and the validated database is exercised to elucidate the effects of alloying and thermal history on the phase equilibrium in Mo-rich alloys.     

Gravitation theory with a Dirac scalar field in the exterior form formalism and the cosmological constant problem

As a consequence of the Poincare-Weyl gauge theory of gravity, the space-time possesses the geometric structure of Cartan-Weyl CW ₄ space with curvature and torsion 2-forms and a Weyltype nonmetricity 1-form. The Dirac field ??(x) appears as an essential additional geometric component with respect to the metric tensor. The conformal theory of gravity coupled with ??(x) in the exterior form formalism is considered. At an early stage of the universe evolution, we consider these field equations for the spatially flat FRWmetric, assuming the densities of ordinarymatter and dark matter to be very small. Then the field equations can be expressed in terms of the metric tensor and ??(t) only and have an exponentially diminishing solution for ??(t), which can explain an exponential decrease of dark energy (the energy of physical vacuum) as a function of time as a consequence of field dynamics in the ultra-early Universe.     

eVEREst—SUPPORTING ESTIMATION OF REAL ESTATE VALUE

Enhanced Value Estimation of Real Estates (eVEREst) is the project carried out at the Department of Management Information Systems at the Poznań University of Economics. The paper presents the idea and the architecture of a system that supports the real estate registry with additional information that enables more precise estimation of real estate value.     

Isolation and characterization of the Saccharomyces cerevisiae DPP1 gene encoding diacylglycerol pyrophosphate phosphatase

Diacylglycerol pyrophosphate (DGPP) is involved in a putative novel lipid signaling pathway. DGPP phosphatase (DGPP phosphohydrolase) is a membrane-associated 34-kDa enzyme from Saccharomyces cerevisiae which catalyzes the dephosphorylation of DGPP to yield phosphatidate (PA) and then catalyzes the dephosphorylation of PA to yield diacylglycerol. Amino acid sequence information derived from DGPP phosphatase was used to identify and isolate the DPP1 (diacylglycerol pyrophosphate phosphatase) gene encoding the enzyme. Multicopy plasmids containing the DPP1 gene directed a 10-fold overexpression of DGPP phosphatase activity in S. cerevisiae. The heterologous expression of the S. cerevisiae DPP1 gene in Sf-9 insect cells resulted in a 500-fold overexpression of DGPP phosphatase activity over that expressed in wild-type S. cerevisiae. DGPP phosphatase possesses a Mg2+-independent PA phosphatase activity, and its expression correlated with the overexpression of DGPP phosphatase activity in S. cerevisiae and in insect cells. DGPP phosphatase was predicted to be an integral membrane protein with six transmembrane-spanning domains. The enzyme contains a novel phosphatase sequence motif found in a superfamily of phosphatases. A dpp1Delta mutant was constructed by deletion of the chromosomal copy of the DPP1 gene. The dpp1Delta mutant was viable and did not exhibit any obvious growth defects. The mutant was devoid of DGPP phosphatase activity and accumulated (4-fold) DGPP. Analysis of the mutant showed that the DPP1 gene was not responsible for all of the Mg2+-independent PA phosphatase activity in S. cerevisiae.     

Risk factors associated with mucositis in cancer patients receiving 5-fluorouracil

Oral mucositis is a dose-limiting toxicity of 5-fluorouracil (5-FU). This prospective cohort study investigated factors associated with mucositis in patients receiving 5-FU for cancer of the digestive tract. Sixty-three patients (mean age 65 years) completed self-administered questionnaires and had interviews, oral examinations and unstimulated whole salivary flow measurements at baseline and follow-up appointments. The duration of follow-up was 2 months. Predictor variables included sociodemographic data, body surface area, diabetes, smoking, alcohol consumption, salivary flow, oral hygiene, presence of prostheses, performance status, regimen of cytotoxic drugs, hematological data, and herpes simplex virus antibody titer. Forty-six per cent of patients developed at least one episode of oral mucositis during cytotoxic treatment. Pearson's chi-square analysis showed that mucositis was significantly associated with xerostomia at baseline, xerostomia during chemotherapy, and lower baseline neutrophil counts (P < or = 0.05). Multiple logistic regression analysis indicated that xerostomia at baseline (odds ratio, OR = 10.0), or baseline neutrophil level under 4000 cells/mm3 (OR = 3.9) were significant predictors of mucositis. Taking into account the effect of neutrophil level at baseline, xerostomia during chemotherapy (OR = 4.5) was also a significant predictor of mucositis. The results showed that xerostomia and lower baseline neutrophil levels are significantly associated with oral mucositis. These variables should be taken into consideration in the design of intervention studies to reduce the frequency and severity of mucositis. More research is required to investigate the role of saliva and neutrophils in the pathogenesis of chemotherapy-induced mucositis.