Tilt angle effects in surface grinding with mounted points

Modern 5-axis machining centers enable the development and use of new machining kinematics and grinding strategies to grind workpieces with superabrasives mounted points. One of these technologies is the oscillating surface grinding (OSG), which can improve the surface characteristics and the tribological properties of machined surfaces. In the current contribution could be observed that the resultant surface roughness values by OSG are not constant within a wavelength of oscillation of the grinding tool. This leads to further studies of the kinematics involved in this process, resulting in the development of a new grinding strategy: the tilt surface grinding (TSG). By using TSG, workpiece surfaces with similar characteristics as OSG could be obtained even without aid of oscillation. In this study, experimental tests are carried out to investigate the influence of parameters involved in these strategies. A significant parameter is the tilt angle α _t, which can be simplified as an angle between the directions of the feed rate in tangential direction v _ft and the feed rate in axial direction v _fa of the grinding tool. The tilt angle α _t is responsible for changes occurred on the OSG when compared to conventional surface grinding. Increasing the tilt angle α _t, a reduction up to 50 % of the roughness values could be achieved. This paper aims to complement and expand the knowledge of the OSG, explaining how the aid of the oscillation tool changes the grinding kinematic, in order to optimize the grinding process.     

Synthesis,Biological Evaluation of 1,1‐Diarylethylenes as a Novel Class of Antimitotic Agents

The cytotoxic activities of 23 new isocombretastatin A derivatives with modifications on the B‐ring were investigated. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. Compounds isoFCA‐4 ( 2 e ), isoCA‐4 ( 2 k ) and isoNH₂CA‐4 ( 2 s ) were the most cytotoxic, and strongly inhibited tubulin polymerization with IC₅₀ values of 4, 2 and 1.5 μM , respectively. These derivatives were found to be 10‐fold more active than phenstatin and colchicine with respect to growth inhibition but displayed similar activities as tubulin polymerization inhibitors. In addition, cell cycle arrest in the G₂/M phase and subsequent apoptosis was observed in three cancer cell lines when treated with these compounds. The disruptive effect of 2 e , 2 k and 2 s on the vessel‐like structures formed by human umbilical vein endothelial cells (HUVEC) suggest that these compounds may act as vascular disrupting agents. Both compounds 2 k and 2 s have the potential for further prodrug modification and development as vascular disrupting agents for treatment of solid tumors.     

Rabies virus quasispecies: implications for pathogenesis

Passage of the mouse-adapted rabies virus strain CVS-24 (where CVS is challenge virus standard) in BHK cells results in the rapid selection of a dominant variant designated CVS-B2c that differs genotypically and phenotypically from the dominant variant CVS-N2c present in mouse-brain- or neuroblastoma-cell-passaged CVS-24. The glycoprotein of CVS-B2c has 10 amino acid substitutions compared with that of CVS-N2c. Because CVS-B2c can be reproducibly selected in BHK cells, it is likely to be a conserved minor subpopulation of CVS-24. CVS-N2c is more neurotropic in vitro and in vivo than CVS-B2c, which replicates more readily in nonneuronal cells in vitro and in vivo. These characteristics appear to be relevant to the pathogenicity of the two variants. CVS-N2c is more pathogenic for adult mice than CVS-B2c. In contrast, CVS-B2c is more pathogenic for neonatal mice. These differences in pathogenicity are reflected in the selection pattern when mixtures of CVS-N2c and CVS-B2c were used to infect neonatal and adult mice. Although CVS-N2c was highly selected in adult mice, no selection for either variant was seen in neonates, suggesting that certain aspects of development, such as maturation of the nervous and immune systems, may contribute to the selection process. We speculate that the existence of different variants within a rabies virus strain may facilitate the virus in overcoming barriers to its spread, both within the host and between species.     

Uric acid, a natural scavenger of peroxynitrite, in experimental allergic encephalomyelitis and multiple sclerosis

Uric acid, the naturally occurring product of purine metabolism, is a strong peroxynitrite scavenger, as demonstrated by the capacity to bind peroxynitrite but not nitric oxide (NO) produced by lipopolysaccharide-stimulated cells of a mouse monocyte line. In this study, we used uric acid to treat experimental allergic encephalomyelitis (EAE) in the PLSJL strain of mice, which develop a chronic form of the disease with remissions and exacerbations. Uric acid administration was found to have strong therapeutic effects in a dose-dependent fashion. A regimen of four daily doses of 500 mg/kg uric acid was required to promote long-term survival regardless of whether treatment was initiated before or after the clinical symptoms of EAE had appeared. The requirement for multiple doses is likely to be caused by the rapid clearance of uric acid in mice which, unlike humans, metabolize uric acid a step further to allantoin. Uric acid treatment also was found to diminish clinical signs of a disease resembling EAE in interferon-gamma receptor knockout mice. A possible association between multiple sclerosis (MS), the disease on which EAE is modeled, and uric acid is supported by the finding that patients with MS have significantly lower levels of serum uric acid than controls. In addition, statistical evaluation of more than 20 million patient records for the incidence of MS and gout (hyperuricemic) revealed that the two diseases are almost mutually exclusive, raising the possibility that hyperuricemia may protect against MS.     

An Expeditious Copper‐Catalyzed Access to 3‐Aminoquinolinones, 3‐Aminocoumarins and Anilines using Sodium Azide

An efficient copper‐catalyzed in situ C(sp²) NH₂ bond formation to provide a range of 3‐aminoquinolin‐2(1H)‐ones and 3‐aminocoumarins from 3‐bromoquinolinones and 3‐bromocoumarins, respectively, has been achieved. The reaction conditions involve the use of copper powder as the catalyst, eco‐friendly ethanol as the solvent in the presence of pipecolinic acid as the ligand and ascorbic acid as the additive. The efficiency of this practical method was demonstrated in the synthesis of various anilines.     

Plasma estradiol concentrations and pharmacokinetics following transdermal application of Menorest 50 or Systen (Evorel) 50

In order to evaluate the applicability of anthelminthic treatment of wild foxes (Vulpes vulpes) to limit their infection with Echinococcus multilocularis, bait pellets, each containing 50 mg praziquantel, were repeatedly distributed in an area of 566 km2 where many foxes are infected, in southern Germany. After six baiting campaigns (15-20 baits/km2) over a period of 14 months, the prevalence of the cestode in foxes, initially 32%, had fallen to 4%. The effect was most pronounced in the central part of the treated area, where no positive fox was found in the 2 months before the end of the trial. The study was controlled for other factors that could influence the parasite's prevalence, such as the availability of intermediate hosts. While the potential of this baiting method to remove E. multilocularis from wild hosts has been demonstrated, the question of its long-term efficacy and other unresolved problems have to be addressed by consecutive studies before routine application can be recommended.     

Assisted Tandem Palladium(II)/Palladium(0)‐Catalyzed C‐ and N‐Arylations of Quinoxalin‐2(1 H)‐ones in Water

A straightforward assisted tandem palladium(II)‐ and palladium(0)‐catalyzed direct C‐3 and N‐4 arylation of quinoxalin‐2(1 H)‐ones with boronic acids and aryl halides in water as safe and cheap solvent is reported. This environmentally friendly catalytic protocol is compatible with a wide range of functional groups and allows construction of various biologically important quinoxalin‐2(1 H)‐one backbones.

     

Major depressive episodes in patients over 70 years of age. Evaluation of the efficiency and acceptability of tianeptine and mianserin

OBJECTIVES: The aim of this multicenter study was to compare the efficacy, acceptability and impact on quality of life of tianeptine (T) and mianserine (M) in patients over 70 years of age with major depression. METHODS: Fulfilment of the DSM IIIR criteria for major depression with a total Montgomery and Asberg depression rating scale (MADRS) of at least 25 and a Hamilton anxiety rating scale (HARS) of at least 18 were required for inclusion. The 315 men and women enrolled in the study were given, by double blind assignment, either T: 37.5 mg/day, T: 25 mg/day or M: 30 mg/day. Treatment duration was 6 months in all three groups and follow-up continued for 3 months after withdrawal of tianeptine or mianserine. The main efficacy criterion was the MADRS score evaluated at each of 6 visits at day 15 (D15) and month 1 (M1), M2, M4, M4.5 and M6. The HARS score was another efficacy criterion. Overall assessment of efficacy and acceptability was done at each visit by the patient and the investigator. Both the patient and the physician estimated global effectiveness on a quality of life scale at M1, M3, M6 and M9. RESULTS: In the intention-to-treat population (n = 299), the antidepressant efficacy of tianeptine and mianserine was not significantly different, whether assessed as effect on anxiety or on quality of life. Scores however tended to be better in the T: 37.5 mg group. Acceptability was good as shown by the low number of adverse events in all 3 groups, but at D15, the incidence of impaired vigilance or equilibrium was significantly lower in the T: 25 mg group than in the M: 30 mg group, emphasizing the advantage of tianeptine in decreasing the risk of falling. Physician-assessed tolerance and acceptability was significantly different at M3 (p = 0.014) and at M6 (p = 0.028) in favor of T: 37.5 mg, indicating that though increasing dosage does not improve efficacy, there is no risk of poorer acceptability. CONCLUSION: These findings reconfirm the antidepressive efficacy, acceptability and safety of tianeptine. They also confirm the anxiolytic aspect associated with the antidepressive effect of tianeptine without any sedative effect. Tianeptine is particularly well indicated in the treatment of depression in elderly or very elderly subjects.     

Abnormalities of Wnt signalling in schizophrenia--evidence for neurodevelopmental abnormality

The Wnt signalling pathway is central to normal brain development in vertebrates and invertebrates and mediates cell fate determination, cell adhesion and cell proliferation. However, its relevance to disorders of cerebral development in man is untested. We evaluated the potential involvement of the Wnt signalling pathway in schizophrenia, a disorder of neurodevelopment origin in which alterations in neuronal lamination and orientation have been described. Using immunohistochemistry and semi-quantitative rating scales, we examined the distribution of two components of the Wnt signalling pathway, beta-catenin and gamma-catenin in the hippocampus and subiculum of 12 schizophrenic (DSMIIR criteria) and 14 control subjects. Both catenins were distributed as intraneuronal diffuse and/or ring shaped forms. The diffuse staining of both forms catenin were reduced in the CA3 and beta-catenin was also reduced in the CA4 hippocampal subregion among schizophrenic subjects. These alternations may represent the basis of the developmental brain abnormalities found in schizophrenia and would have functionally important consequences in the adult.