253 research outputs found

    Study of lubricant jet flow phenomena in spur gears

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    Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 rpm using a 8.89 cm (3.5 inch) pitch diameter 8 pitch spur gear at oil pressures from 70,000 to 410,000 n/sqm (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet. An analytical model was developed for the vectorial impingement dept and for the impingement depth with tooth space windage effects included. The windage effects for oil drop size greater than .0076 cm (.003 inches). The analytical impingement dept compared favorably with experimental results above an oil jet pressure of 70,000 n/sqm (10psi). There was further penetration into the tooth space after impingement, but much of this oil was thrown out of the tooth space without further contacting the gear teeth

    Decohering the Fermi liquid: A dual approach to the Mott Transition

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    We present a theoretical approach to describing the Mott transition of electrons on a two dimensional lattice that begins with the low energy effective theory of the Fermi liquid. The approach to the Mott transition must be characterized by the suppression of density and current fluctuations which correspond to specific shape deformations of the Fermi surface. We explore the nature of the Mott insulator and the corresponding Mott transition when these shape fluctuations of the Fermi surface are suppressed without making any a prior assumptions about other Fermi surface shape fluctuations. Building on insights from the theory of the Mott transition of bosons, we implement this suppression by identifying and condensing vortex degrees of freedom in the phase of the low energy electron operator. We show that the resulting Mott insulator is a quantum spin liquid with a spinon fermi surface coupled to a U(1) gauge field which is usually described within a slave particle formulation. Our approach thus provides a coarse-grained treatment of the Mott transition and the proximate spin liquid that is nevertheless equivalent to the standard slave particle construction. This alternate point of view provides further insight into the novel physics of the Mott transition and the spin liquid state that is potentially useful. We describe a generalization that suppresses spin anti-symmetric fluctuations of the Fermi surface that leads to a spin-gapped charge metal previously also discussed in terms of slave particle constructions.Comment: 10 pages, 2 figure

    Bosonic Analogue of Dirac Composite Fermi Liquid

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    Selecting a bedside cognitive vital sign to monitor cognition in hospital: feasibility, reliability, and responsiveness of logical memory

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    Although there is a high prevalence of delirium and cognitive impairment among hospitalised older adults, short, reliable cognitive measures are rarely used to monitor cognition and potentially alert healthcare professionals to early changes that might signal delirium. We evaluated the reliability, responsiveness, and feasibility of logical memory (LM), immediate verbal recall of a short story, compared to brief tests of attention as a bedside “cognitive vital sign” (CVS). Trained nursing staff performed twice-daily cognitive assessments on 84 clinically stable inpatients in two geriatric units over 3–5 consecutive days using LM and short tests of attention and orientation including months of the year backwards. Scores were compared to those of an expert rater. Inter-rater reliability was excellent with correlation coefficients for LM increasing from r = 0.87 on day 1 to r = 0.97 by day 4 (p < 0.0001). A diurnal fluctuation of two points from a total of 30 was deemed acceptable in clinically stable patients. LM scores were statistically similar (p = 0.98) with repeated testing (suggesting no learning effect). All nurses reported that LM was feasible to score routinely. LM is a reliable measure of cognition showing diurnal variation but minimal learning effects. Further study is required to define the properties of an ideal CVS test, though LM may satisfy these

    Vinorelbine alternating oral and intravenous plus epirubicin in first-line therapy of metastatic breast cancer: results of a multicentre phase II study

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    The combination of intravenous (i.v.) vinorelbine and epirubicin is highly active in the treatment of metastatic breast cancer (MBC). In an effort to improve patient convenience, we investigated a regimen alternating i.v. and oral vinorelbine in combination with epirubicin as first-line chemotherapy of patients with MBC. In all, 49 patients with MBC received, as first-line treatment, a combination regimen consisting of i.v. vinorelbine 25 mg m−2 plus epirubicin 90 mg m−2 given on day 1, and oral vinorelbine 60 mg m−2 on day 8 (or day 15 if neutrophils <1500 mm−3) every 3 weeks, in an open-label, multicentre phase II study. Treatment was to be repeated for a maximum of six cycles. The study population had a median age of 55 years, half of the patients had received prior adjuvant chemotherapy and 86% presented a visceral involvement. In all, 25 responses were documented and validated by an independent panel review, yielding response rates of 51% (95% CI: 36–66) in the 49 enrolled patients and 54.5% (95% CI: 39–70) in the 44 evaluable patients. Median durations of progression-free survival and survival were 8 and 20 months, respectively. Neutropenia was the main dose-limiting toxicity, but complications were uncommon, four patients having experienced febrile neutropenia and six having developed neutropenic infection. Other frequently reported adverse events included stomatitis, nausea and vomiting, which were rarely severe. No toxic death was reported. Among patients who received six cycles, global score of quality of life remained stable. This regimen alternating oral and i.v. vinorelbine in combination with epirubicin is effective and safe. Oral vinorelbine on day 8 offers greater convenience to the patient, and decreases the need for i.v. injection and reduces time spent in hospital. Therefore, oral vinorelbine is a convenient alternative to the i.v. form in combination regimens commonly used to treat MBC

    Enantiopure titanocene complexes: direct evidence for paraptosis in cancer cells

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    Tolerated by normal tissues, anti-cancer therapies based on titanium compounds are limited by low efficacy/selectivity and lack of understanding of their mode(s) of action. In vitro antitumour activity and mode of cell death incurred by enantiopure TiCl2{n-C5H4CHEt(2 MeOPh)}2 (abbreviated CpR 2TiCl2) has been investigated. The in vitro anti-tumour activity of CpR 2TiCl2 is selective for cancer cells; in clonogenic assays, (S,S)-CpR 2TiCl2 was twice as effective at inhibiting colony formation than other stereoisomers after 24 h exposure. HPLC, MS and NMR techniques determined hydrolysis of CpR 2TiCl2; data strongly correlate with soluble [CpR 2Ti(OH (OH2)]+ being the biological trigger. Treatment of cells with CpR 2TiCl2 provoked extensive cytoplasmic vacuolization, endoplasmic reticulum (ER) swelling and activation of MAPKinase signal transduction, consistent with ligand-induced paraptosis, type III cell death, which is morphologically distinct from, and independent of apoptosis. Indeed, distinct from cisplatin, CpR 2TiCl2 failed to perturb cell cycle dynamics, induce γH2AX foci or evoke apoptosis in MDA-MB-468 and HCT-116 cells
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