Prediction of heats of mixing of liquid mixtures containing aliphatic hydrocarbons and ketones by a group solution model

A group solution model for heats of mixing of liquid mixtures has been tested and found satisfactory for mixtures containing ketones and alkanes. No provision was made for a skeletal contribution Group contribution functions were generated from experimental data on acetone/n-hexane mixtures at 25°C and are presented. These functions allow the prediction of heats of mixing of binary or multicomponent mixtures containing alkanes and/or ketones at 25°C. No experimental data are required     

A novel thermal sensor concept for flow direction and flow velocity

This paper presents a unified theory for different measurement concepts of a thermal flow sensor. Based on this theory, a new flow sensor concept is derived. The concept allows measuring both direction and velocity of a fluid flow with a heater and an array of temperature sensors. This paper first analyzes the two-dimensional (2-D) forced convection problem with a laminar flow. The two operation modes of a constant heating power and of a constant heater temperature are considered in the analytical model. A novel estimation algorithm was derived for the flow direction. Different methods for velocity measurement were presented: the hot-wire method, the calorimetric method, and the novel average-temperature method. The only geometric parameter of the sensor, the dimensionless position of the sensor array, is optimized based on the analytical results. Furthermore, the paper presents the experimental results of the sensor prototype. In order to verify the analytical model, an array of temperature sensors was used for recording the 2-D temperature profile around the heater. Temperature values are transferred to a computer by a multiplexer. A program running on a personal computer extracts the actual flow velocity and flow direction from the measured temperature data. This paper discusses different evaluation algorithms, which can be used for this sensor. A simple Gaussian estimator was derived for the direction measurement. This estimator provides the same accuracy as the analytical estimator. Velocity results of both the calorimetric concept and the novel average-temperature concept are also presented.     

Cryomilling for the fabrication of a particulate B4C reinforced Al nanocomposite: Part II. Mechanisms for microstructural evolution

Cryomilling was successfully employed to fabricate particulate B₄C-reinforced Al matrix nanocomposite powders. In order to investigate the microstructural evolution during cryomilling, composite powders were milled for different times. These powders were collected from the milling chamber and the microstructures were characterized to reveal the formation mechanism for this nanocomposite. The microstructural evolution, including the morphology and size of the milled composite powders, the size and distribution of the B₄C, and the dimension of the Al grains, is discussed on the basis of the experimental results.     

A Quantitative Measure to Evaluate Competing Designs for Non‐linear Dynamic Process Identification

The strategy for the collection of information (i.e., data) for model development is called experimental design. Optimal design seeks to maximize the information content under constraints of time and sampling. In the system identification literature the dominant strategy has been the method of pseudo random sequences (PRS). However, this work demonstrates that statistical design of experiments (SDOE) can provide greater information content as quantitatively measured by the D‐optimal criterion.     

Implementation of a home-based program for early detection of clinical deterioration in cystic fibrosis

A statistical decision-making system, based on daily self measurements obtained at home, has been developed that will predict the clinical status of a patient with cystic fibrosis (CF). The data for the study were collected from patients randomly selected from those served by the University of Minnesota CF Center. Participants recorded four daily measurements (weight, vital capacity, breathing rate, and resting pulse) and one weekly measurement (height) and returned completed diaries to the coordinating center each week. The goal of the rule was to determine whether each patient's clinical status was deteriorating, remaining stable, or improving at the time of the most recent set of weekly measurements. This early detection and intervention criterion (EDIC) is being used in the clinical setting to aid in the management of patients with cystic fibrosis. The computer hardware and software, particularly the relational database, have provided an efficient basis for the continued use of EDIC.     

Study of human isoursodeoxycholic acid metabolism

BACKGROUND/AIMS: The aim of this study was to examine the metabolism of isoursodeoxycholic acid (isoUDCA) in humans. METHODS: IsoUDCA was synthesized of >99% purity and administered orally for 1 week, 3 x 250 mg/day, to six healthy male subjects. Bile acids were extracted from duodenal bile, serum, and 24-h urine samples collected before and at the end of the study period, separated into groups of conjugates, and analyzed by gas chromatography-mass spectrometry and fast atom bombardment mass spectrometry. RESULTS: IsoUDCA was tolerated without any side effect. Liver function tests did not change. Bile acid concentrations (mean+/-SEM) increased from 11.9+/-1.87 to 15.3+/-1.37 mmol/l in bile (n.s.), and from 3.4+/-0.10 to 6.8+/-0.43 micromol/l in serum (p<0.05). Urinary excretion of bile acids increased from 5.3+/-0.29 to 82.2+/-7.84 micromol/24 h (p<0.01). All changes were due to significant increases of isoUDCA and UDCA in bile, serum and urine, and of 3-dehydro-UDCA, the 3-oxo intermediate of isomerization, in bile and in serum. The relative enrichments of isoUDCA, UDCA, and 3-dehydro-UDCA, were: in bile, 2.2%, 25.7%, and 0.7%; in serum, 24.7%, 23.5%, and 6.1%; and in urine, 83.7%, 2.0%, and 2.4%. Whereas 78% of serum isoUDCA was unconjugated, 93-94% of biliary and urinary isoUDCA was conjugated with N-acetylglucosamine. CONCLUSIONS: This study indicates good tolerance and significant intestinal absorption of orally administered isoUDCA. IsoUDCA is extensively isomerized, probably both by intestinal and hepatic enzymes to yield UDCA which became the major biliary compound. In vitro, using the human hepatoblastoma cell line Hep G2, isoUDCA was found to be cytoprotective towards ethanol-induced cell injuries.     

Electrodeposited α-PbO2 and β-PbO2 in sulfuric acid: Recharge,cycling and morphology

Experiments have shown that a structural transformation, β→α, was likely to occur during deep cycling of electrodeposited β-PbO₂ in 8N H₂SO₄, and that the appearance of α-PbO₂, in formerly pure β-PbO₂, was responsible for the enhancement of the capacity. The presence of α-PbO₂ also facilitated the growth process of β-PbO₂ during the charging.     

WISC—R and WAIS—R odd- and even-item short forms: Criterion validity in three patient samples.

Examined the validity of Wechsler Intelligence Scale for Children—Revised (WISC—R) and Wechsler Adult Intelligence Scale—Revised (WAIS—R) odd-item and even-item short forms in 123 child and adolescent outpatients (82 males, 41 females), and rescored and reanalyzed data from studies involving 21 male and 23 female adult clinical outpatients (C. Watkins et al; see record 1988-18935-001), and 54 male medical inpatients (C. Watkins et al; see record 1987-20807-001). The method described by J. Edinger et al (see record 1986-18942-001) and two other odd- and even-item methods were not consistently valid for any of the samples; odd- and even-item short-form strategy may not be effective across populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rational design of a triple helix-specific intercalating ligand

DNA triple helices offer new perspectives toward oligonucleotide-directed gene regulation. However, the poor stability of some of these structures might limit their use under physiological conditions. Specific ligands can intercalate into DNA triple helices and stabilize them. Molecular modeling and thermal denaturation experiments suggest that benzo[f]pyrido[3, 4-b]quinoxaline derivatives intercalate into triple helices by stacking preferentially with the Hoogsteen-paired bases. Based on this model, it was predicted that a benzo[f]quino[3,4-b]quinoxaline derivative, which possesses an additional aromatic ring, could engage additional stacking interactions with the pyrimidine strand of the Watson-Crick double helix upon binding of this pentacyclic ligand to a triplex structure. This compound was synthesized. Thermal denaturation experiments and inhibition of restriction enzyme cleavage show that this new compound can indeed stabilize triple helices with great efficiency and specificity and/or induce triple helix formation under physiological conditions.