Evaluation of Atmospheric and Vacuum Residues Using Molecular Distillation and Optimization

The term atmospheric residue describes the material at the bottom of the atmospheric distillation tower having a lower boiling point limit of about 340°C; the term vacuum residue (heavy petroleum fractions) refers to the bottom of the vacuum distillation, which has an atmospheric equivalent boiling point (AEBP) above 540°C. In this work, the objective is to evaluate the behavior of different kinds of Brazilian atmospheric and vacuum residues using molecular distillation. The Falling Film Molecular Distillator was used. For the results obtained through this process, a significant range of temperature can be explored avoiding the thermal decomposition of the material. So these results are very important to the refinery decisions and improvements. The Experimental Factorial Design results showed that the temperature has more influence on the process than the feed flow rate, when a higher percentage of distillate is required.     

Role of Perceived Importance in Intergroup Contact.

Furthering G. W. Allport's (1954) contentions for optimal contact, the authors introduce a new construct: the perceived importance of contact. They propose that perceived importance is the best proximal predictor of contact's reduction of prejudice. If individuals have opportunities for contact at work or in the neighborhood, their chances to have intergroup acquaintances and friends increase. Intergroup contact among acquaintances and friends can be perceived as more or less important, which in turn determines intergroup evaluations. A 1st study shows that the new measure of perceived importance is indeed distinct from established quantity and quality indicators. The results are cross-validated in a 2nd study that also sheds light on the meaning of importance. In 3rd and 4th studies, structural equation analyses and a meta-analysis support the hypotheses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Treatment of hypertension in nondiabetic renal disease

To clarify whether long-term impaired glucose tolerance (IGT) is associated with dysfunction of peripheral and autonomic nerves, age-matched men with IGT and diabetes mellitus were followed prospectively for 12-15 years, when peripheral and autonomic nerve function was assessed. The patients comprised four subgroups: (1) 51 IGT subjects (duration of IGT at least 12-15 years); (2) 35 diabetic patients, with IGT 12-15 years ago, who later developed diabetes; (3) 34 diabetic patients, duration of diabetes at least 12-15 years; and (4) 62 age-matched non-diabetic control subjects. Mean age of the whole study population was 61 +/- 2 years (mean +/- SD), not different in the four groups. Peripheral nerve function tests included nerve conduction velocities, amplitudes, distal latencies, F-reflexes, and sensory perception thresholds for heat, cold, and vibration. Autonomic nerve function tests included the heart rate reaction during deep breathing (expiration to inspiration ratio) and to tilt (acceleration and brake indices). Despite 12-15 years of IGT, peripheral nerve function did not differ between IGT and control subjects, whereas autonomic nerve function deviated; an abnormal expiration to inspiration ratio (a sign of vagal nerve dysfunction) was significantly more common (15/51 versus 5/62; p < 0.01) in IGT than in control subjects. Diabetic patients (groups 2 and 3) showed lower conduction velocities (in general 2-4 m s-1 lower) than IGT and control subjects in all tested nerves. In conclusion, diabetes but not IGT, is associated with peripheral nerve dysfunction.     

Embedded is the new paradigm(s)

Embedded computing moved beyond toasters quite some time ago, but there are still misconceptions about what embedded computers do. Some of those misconceptions come from an old-fashioned view of what a computer is.     

Evidence for superantigen involvement in insulin-dependent diabetes mellitus aetiology

Insulin-dependent diabetes mellitus (IDDM) is a T-cell-mediated autoimmune disease whose onset is believed to be triggered by unknown environmental factors acting on a predisposing genetic background. Islet-infiltrating T (IIT) cells from two IDDM patients, who had died at the onset of the disease from brain swelling as a complication of ketoacidosis, were analysed. The results provided evidence for the involvement of a pancreatic islet cell membrane-bound superantigen as a diabetes aetiopathogenetic factor. There was a selective expansion of a T-cell receptor (TCR) variable segment of the beta-chain (V beta 7) in these IIT cells in association with unselected V alpha-chain segments; extensive junctional diversity of the TCR V beta 7 chains; and evidence of positive selection, after exposure to diabetic islet cell membrane preparations, of V beta 7+ T-cell clones among peripheral blood lymphocytes from non-diabetic individuals.     

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine as a substrate of cytochrome P450 2D6: allosteric effects of NADPH-cytochrome P450 reductase

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin that produces Parkinsonism symptoms in man, has been examined as a substrate of recombinant human cytochrome P450 2D6. When cumene hydroperoxide is used as an oxygen and electron donor, a single product is formed, identified as 4-phenyl-1,2,3,6-tetrahydropyridine. The K(m) for formation of this product (130 microM) is in agreement with the dissociation constants for MPTP binding to the enzyme determined by optical and nuclear magnetic resonance (NMR) spectroscopy. When the reaction is carried out with nicotinamide adenine dinucleotide phosphate (reduced) (NADPH) and recombinant human NADPH-cytochrome P450 reductase, a second product, identified as 1-methyl-4-(4'-hydroxyphenyl)-1,2,3,6-tetrahydropyridine, is formed in addition to 4-phenyl-1,2,3,6-tetrahydropyridine. The K(m) values for formation of these two products are 19 microM and 120 microM, respectively. Paramagnetic relaxation experiments have been used to measure distances between the protons of bound MPTP and the heme iron, and these have been used to construct models for the position and orientation of MPTP in the active site. For the cytochrome alone, a single mode of binding was observed, with the N-methyl close to the heme iron in a position appropriate for the observed N-demethylation reaction. In the presence of the reductase, the data were not consistent with a single mode of binding but could be explained by the existence of two alternative orientations of MPTP in the active site. One of these, characterized by a dissociation constant of 150 microM, is essentially identical to that observed in the absence of the reductase. In the second, which has a K(d) of 25 microM, the MPTP is oriented so that the aromatic ring is close to the heme iron, in a position appropriate for p-hydroxylation leading to the formation of the product seen only in the presence of the reductase. In the case of codeine, another substrate for cytochrome P450 2D6, the addition of reductase had no effect on the nature of the product formed, the dissociation constant, or the orientation in the binding site. These observations show that NADPH-cytochrome P450 reductase has an allosteric effect on the active site of cytochrome P450 2D6 that affects the binding of some substrates but not others.     

Arterial reactivity is enhanced in genetic males taking high dose estrogens

OBJECTIVES: We sought to assess whether high dose estrogen treatment is associated with enhanced arterial reactivity in genetic males. BACKGROUND: Although estrogens have been shown to enhance arterial reactivity in women, and are thereby thought to confer cardiovascular benefit, the vascular effects of long-term estrogen therapy in genetic males is unknown. METHODS: We studied the arterial physiology of 30 genetic males--15 male to female transsexuals receiving long-term high dose estrogen therapy and 15 healthy male control subjects matched for age, smoking history and vessel size. Using external vascular ultrasound, brachial artery diameter was measured at rest, after flow increase (causing endothelium-dependent dilation [EDD]) and after nitroglycerin (GTN), an endothelium-independent dilator. Blood pressure, cholesterol and testosterone levels were also measured in each subject. RESULTS: Total testosterone and free testosterone index levels were lower in the transsexuals compared with the control subjects (p < 0.001). In contrast, EDD was significantly higher in the transsexuals than in the control males (mean [+/-SD] 7.1 +/- 3.1% vs. 3.2 +/- 2.8%, p = 0.001), as was the GTN response (21.2 +/- 6.7% vs. 14.6 +/- 3.3%, p = 0.002). Total and high density lipoprotein cholesterol, blood pressure levels and baseline vessel size were similar in the two groups. On multivariate analysis, enhanced EDD was associated independently with estrogen therapy (p = 0.02) and with low total cholesterol (p = 0.04). An enhanced GTN response was also significantly associated with estrogen therapy (p = 0.03). CONCLUSIONS: Long-term treatment with high dose estrogens is associated with enhanced arterial reactivity in genetic males, which may be due to the effects of estrogen excess or androgen deprivation, or both.     

The use of quantitative bacteriologic assessment of bone

A new sub-class of binding protein-dependent transporter with specificity for a broad range of polar amino acids has been identified by sequence comparison, in Rhizobium leguminosarum, Rhodobacter capsulatus, Escherichia coli and Pseudomonas fluorescens. Southern blotting and PCR analysis has shown that transporters from this new sub-class are widely distributed in Gram-negative bacteria, including, in addition to the above, Citrobacter freundii, Erwinia carotovorum and Rhizobium meliloti. ABC transporters of polar amino acids can be divided into two groups: those with narrow solute specificity and the newly identified sub-class with broad solute specificity. The binding and inner membrane proteins from transporters with a broad solute specificity are larger by approximately 30% than those with a narrow solute specificity. Multiple alignment of the inner membrane proteins from all sequenced polar amino acid transporters indicates there is an N-terminal conserved region that may be involved in solute specificity. A conserved arginine or lysine at residue 30 of this region is changed to glutamate in arginine transporters. Residue 53 also has a strong correlation with the charge on the transported solute, with basic amino acid transporters replacing an aliphatic amino acid at this position with a negatively charged amino acid. The general amino acid permease from R. leguminosarum, which will transport aliphatic as well as basic and acidic amino acids, juxtaposes two prolines at residues 52 and 53 of the N-terminal conserved region.     

Enhancing effect of natural killer cell stimulatory factor (NKSF/interleukin-12) on cell-mediated cytotoxicity against tumor-derived and virus-infected cells

Natural killer cell stimulatory factor (NKSF) or interleukin-12 (IL-12) is a heterodimeric cytokine with pleiomorphic effects on T and NK cells, including induction of lymphokine production, mitogenesis, and enhancement of spontaneous cytotoxic activity. Similarly to IL-2, NKSF/IL-12 enhances NK cell-mediated cytotoxicity within a few hours and independently from induced proliferation. This effect is independent from other induced cytokines, because it is not prevented by antibodies neutralizing interferon (IFN)-alpha, IFN-beta, IFN-gamma, IL-2 or tumor necrosis factor (TNF)-alpha and, unlike the induction of IFN-gamma production by peripheral blood lymphocytes, it does not require HLA class II-positive accessory cells. Enhanced cytotoxicity is accompanied by morphologic changes in NK cells, including a significant increase in the number of cytoplasmic granules. In addition to the previously described ability to enhance the cytotoxic activity of NK cells against tumor-derived target cells, NKSF/IL-12 is also a potent stimulator of cytotoxicity against virus-infected cells, either fibroblasts acutely infected with herpes viruses or T cell lines chronically infected with human immunodeficiency virus-1. NK cell-mediated antibody-dependent cytotoxicity or anti-CD16 antibody-redirected lysis is not significantly enhanced by NKSF/IL-12. However, the ability of resting peripheral blood T cells to mediate anti-CD3 antibody-redirected lysis is enhanced by 18-h incubation with NKSF/IL-12, indicating that this lymphokine can modulate the cytotoxic capability of both NK and T cells.