Fluidization studies in large gas—solid systems. Part IV. Similarity criteria for different size systems

Time average differential pressure profiles have been recorded at the base of fluidized beds with cross-sectioned areas of 0.375 and 1.5 m², both being fitted with uniform resistance gas distributors and containing various materials. For beds of a specific material, with equal ratios of defluidized bed depth/bed width (within the limits 0.375 – 1.5), a common relationship was found between the time average differential pressure difference between the centre and corners at the bed base (expressed as a fraction of total theoretical bed pressure drop at incipient fluidizing conditions) and superficial gas velocity.     

The removal of dichloromethane from atmospheric pressure air streams using plasma-assisted catalysis

Plasma-assisted catalysis was used for the destruction of 500 ppm of dichloromethane, CH₂Cl₂ (DCM), in gas streams of air using a non-thermal, atmospheric pressure plasma utilising a dielectric packed bed. The combination of plasma and catalyst gave improved destruction of DCM. Eight catalysts which including alumina, TiO₂ and various zeolites were investigated with the finding that alumina in a one-stage reactor configuration and TiO₂ and HZSM-5 in two-stage configurations gave the best DCM destructions. The sodium zeolites are capable of reducing by 50% the unwanted NO_x by-products, formed by plasma processing in air. The nature of the catalyst is important in terms of the destruction efficiency, end-product selectivity and NO_x reduction.     

Thermal degradation of polymers. X. Thermal analysis studies on poly(p-N,N-dimethylaminostyrene) homopolymers and copolymers with styrene in nitrogen

Studies have been made on the effect of the molecular weight of p-N,N-dimethylaminostyrene homopolymers and the composition of its copolymers with styrene on the glass transition temperature. Comparative thermal degradation studies have been made on polystyrene and p-N,N-dimethylaminostyrene polymers by thermal analytical methods (TG, DTA, and DSC). The differences in thermal stability and overall thermal degradation behavior of the two systems are discussed in terms of the differences in their degradation mechanisms.     

Description and evaluation of a new 3-D computerized treatment planning dose compensator system

Evaluation has been performed of compensators generated by means of a computerized three-dimensional treatment planning system that can utilize either digitized slice profiles or CT scans. Two methods of calculating compensator thickness are used: the modified Batho power law (dSAR) method for digitized profiles and the equivalent TAR (eqTAR) method for CT scans. This system not only compensates for patient surface contours but also compensates for internal inhomogeneities. In addition, any required wedging will be incorporated in the compensator generation. This system has been tested for a number of extreme cases with inhomogeneities and sloping contours. Good agreement was obtained between the measured and computer calculated dose profiles especially along the central axis of the beam. A "Profile Uniformity Index" was defined to quantify the goodness of dose compensation in three dimensions. Compensation using this system can achieve good dose uniformity within the target volume in all clinical cases and is definitely an improvement over systems based solely on tissue deficit.     

Trace detection of krypton using laser-induced fluorescence

Highly sensitive detection of neutral Kr atoms was accomplished by the use of laser-induced fluorescence. In one experiment, Kr at 40 parts per 10(12) in He was detected at a signal-to-noise ratio of 500 by time-resolved fluorescence measurements. The Kr metastable 1s(5) level was populated by cascade after two-photon excitation to the 2p(6) level by the frequency-tripled output of a pulsed single-longitudinalmode dye laser. After a delay, when scattered laser light and cascade resonance fluorescence became negligible, trace quantities of Kr were detected by the use of a pulsed-laser pumping scheme. In a related experiment, (78)Kr/(86)Kr isotope ratios ranging from 1 to 0.1 were measured with a resonant isotopic depletion technique first proposed by Makarov [Sov. J. Quantum Electron. 13, 722 (1983)]. The (86)Kr metastable population was selectively depleted by optical pumping to a higher-lying state that relaxed to the ground state by means of radiative cascade. After the (78)Kr/(86)Kr ratio of metastables had been enriched by a factor of 10, the (78)Kr population was probed by pulsed excitation. Premixed (78)Kr/(86)Kr ratios were measured to within an accuracy of 10%, even for unresolved, Doppler-broadened transitions.     

Using the Nutrition Screening Initiative to survey the nutritional status of clients participating in a home delivered meals program

A large percentage of older Americans are at risk for malnutrition. This puts them at risk for premature institutionalization, creating a financial burden. The objective of this survey was to determine the nutritional health of clients receiving home delivered meals in Lake County, Indiana and the impact that home delivered meals had on them. Nutrition Screening Initiative (NSI) Determine Your Nutritional Health Checklists were mailed to recipients of meals; 58.3% were returned. Twenty-eight percent were found to be at no nutritional risk, 39% at moderate nutritional risk and 33% at high nutritional risk. One-hundred-thirty clients that scored three or more on the "Checklist" were visited by a Registered Dietitian for further screening using the NSI Level I Screen. This screen found many nutritional problems but the fact that the clients did receive home delivered meals decreased the risk. It was determined by the author that 68% of these clients could not function in their own homes without home delivered meals.     

Just-in-time defect prediction for software hunks

Just-in-time defect prediction can remind software developers and managers to verify and fix bugs at the moment they appeared, thus improving the effectiveness and validity of bug fixing. Existing studies mainly focus on just-in-time prediction for software files (JIT-F). JIT-F is a binary classification problem, which classifies (hence predicts) a file change as buggy or clean. This article provides a detailed analysis of just-in-time defect prediction for software hunks (JIT-H), which predicts bugs at a finer level of granularity, and hence further improves the efficiency of bug fixing. Classification is performed using the ensemble technique of bagging—aggregated combinations of random under sampling plus multiple classifiers (J48 and Random Forest). An empirical study with 10 open source projects was conducted to validate the effectiveness of JIT-H. Experimental results show that JIT-H is effective at predicting defects in software hunk changes. Compared with JIT-F, JIT-H is more cost effective. Additionally, analysis on the change features indicates that Text Vector features and hunk change level features are of more importance than features in other groups and levels.     

Differentiation of promonocytic U937 subclones into macrophagelike phenotypes regulates a cellular factor(s) which modulates fusion/entry of macrophagetropic human immunodeficiency virus type 1

Monocytes/macrophages (M/M) and CD4+ T cells are two important targets of human immunodeficiency virus (HIV) infection. Different strains of HIV-1 vary markedly in their abilities to infect cells belonging to the M/M lineage. Macrophagetropic (M-tropic) HIV-1 strains replicate well in primary lymphocytes as well as in primary macrophages; however, they generally infect T-cell lines poorly, if at all. Although promonocytic cell lines such as U937 have been used as in vitro models of HIV-1 infection of M/M, these cell lines are susceptible to certain T-cell-tropic (T-tropic) HIV-1 strains but are resistant to M-tropic HIV-1. In this study, we demonstrate that (i) certain U937 clones ("plus" clones), which are susceptible only to T-tropic HIV-1, become highly susceptible to M-tropic HIV-1 upon differentiation with retinoic acid (RA); (ii) other U937 clones ("minus" clones), which are resistant to both T- and M-tropic HIV-1, remain resistant to both viruses; and (iii) RA treatment induces expression of CCR5, a fusion/entry cofactor for M-tropic HIV-1 in both types of U937 clones, and yet enhances the fusogenicity of the plus clones, but not the minus clones, with M-tropic Env's. These results indicate that the major restriction of M-tropic HIV-1 infection in promonocytic cells occurs at the fusion/entry level, that differentiation into macrophage-like phenotypes renders some of these cells highly susceptible to infection with M-tropic HIV-1, and that CD4 and CCR5 may not be the only determinants of fusion/entry of M-tropic HIV-1 in these cells.     

Refining the level for anticipated hepatotoxicity in acetaminophen poisoning

Treatment of an acetaminophen overdose with N-acetyl cysteine usually is based on the position of the 4-h acetaminophen (APAP) level on the Rumack-Matthew nomogram; however, there is disagreement on the level at which clinically relevant hepatotoxicity occurs. A retrospective review of all acute adult formulation APAP exposures reported to our poison center between 1986 and 1993 was performed and cases corresponding to the "possible risk or toxicity" range on the nomogram were identified. Our current poison center protocol for APAP poisoning does not recommend treatment with N-acetylcysteine (NAC) in low-risk patients if the 4-h serum APAP level or the extrapolated equivalent falls within the possible toxicity range on the nomogram. Seventeen cases met the inclusion criteria for the study and received no NAC; six additional patients met inclusion criteria but received one or two doses of NAC before therapy was discontinued. No patients in either group demonstrated clinical evidence of hepatotoxicity. This pilot study suggests that patients with no risk factors and APAP levels in the "possible risk" range may not require NAC therapy.     

Hamstrings and psoas lengths during normal and crouch gait: implications for muscle-tendon surgery

OBJECTIVE: To study the relative contribution of the lung and the chest wall on the total respiratory system mechanics, gas exchange, and work of breathing in sedated-paralyzed normal subjects and morbidly obese patients, in the postoperative period. SETTING: Policlinico Hospital, University of Milan, Italy. METHODS: In ten normal subjects (normal) and ten morbidly obese patients (obese), we partitioned the total respiratory mechanics (rs) into its lung (L) and chest wall (w) components using the esophageal balloon technique together with airway occlusion technique, during constant flow inflation. We measured, after abdominal surgery, static respiratory system compliance (Cst,rs), lung compliance (Cst,L), chest wall compliance (Cst,w), total lung (Rmax,L) and chest wall (Rmax,w) resistance. Rmax,L includes airway (Rmin,L) and "additional" lung resistance (DR,L). DR,L represents the component due to viscoelastic phenomena of the lung tissue and time constant inequalities (pendelluft). Functional residual capacity (FRC) was measured by helium dilution technique. RESULTS: We found that morbidly obese patients compared with normal subjects are characterized by the following: (1) reduced Cst,rs (p < 0.01), due to lower Cst,L (55.3 +/- 15.3 mL x cm H2O-1 vs 106.6 +/- 31.7 mL x cm H2O-1; p < 0.01) and Cst,w (112.4 +/- 47.4 mL x cm H2O-1 vs 190.7 +/- 45.1 mL x cm H2O-1; p < 0.01); (2) increased Rmin,L (4.7 +/- 3.1 mL x cm H2O x L-1 x s; vs 1.0 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01) and DR,L (4.9 +/- 2.6 mL x cm H2O x L-1 x s; vs 1.5 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01); (3) reduced FRC (0.665 +/- 0.191 L vs 1.691 +/- 0.325 L; p < 0.01); (4) increased work performed to inflate both the lung (0.91 +/- 0.25 J/L vs 0.34 +/- 0.08 J/L; p < 0.01) and the chest wall (0.39 +/- 0.13 J/L vs 0.18 +/- 0.04 J/L; p < 0.01); and (5) a reduced pulmonary oxygenation index (PaO2/PAO2 ratio). CONCLUSION: Sedated-paralyzed morbidly obese patients, compared with normal subjects, are characterized by marked derangements in lung and chest wall mechanics and reduced lung volume after abdominal surgery. These alterations may account for impaired arterial oxygenation in the postoperative period.