361 research outputs found

    Baseline tests of the EPC Hummingbird electric passenger vehicle

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    The rear-mounted internal combustion engine in a four-passenger Volkswagen Thing was replaced with an electric motor made by modifying an aircraft generator and powered by 12 heavy-duty, lead-acid battery modules. Vehicle performance tests were conducted to measure vehicle maximum speed, range at constant speed, range over stop-and-go driving schedules, maximum acceleration, gradeability limit, road energy consumption, road power, indicated energy consumption, braking capability, battery charger efficiency, and battery characteristics. Test results are presented in tables and charts

    Wnt signaling induces differentiation of progenitor cells in organotypic keratinocyte cultures

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    BACKGROUND: Interfollicular skin develops normally only when the activity of the progenitor cells in the basal layer is counterbalanced by the exit of cells into the suprabasal layers, where they differentiate and cornify to establish barrier function. Distinct stem and progenitor compartments have been demonstrated in hair follicles and sebaceous glands, but there are few data to describe the control of interfollicular progenitor cell activity. Wnt signaling has been shown to be an important growth-inducer of stem cell compartments in skin and many other tissues. RESULTS: Here, we test the effect of ectopic Wnt1 expression on the behavior of interfollicular progenitor cells in an organotypic culture model, and find that Wnt1 signaling inhibits their growth and promotes terminal differentiation. CONCLUSION: These results are consistent with the phenotypes reported for transgenic mice engineered to have gain or loss of function of Wnt signaling in skin, which would recommend our culture model as an accurate one for molecular analysis. Since it is known that canonical ligands are expressed in skin, it is likely that this pathway normally regulates the balance of growth and differentiation, and suggests it could be important to pathogenesis

    Long‐Term Responses Of The Kuparuk River Ecosystem To Phosphorus Fertilization

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117218/1/ecy2004854939.pd

    Reduced Self-Reactivity of an Autoreactive T Cell After Activation with Cross-reactive Non–Self-Ligand

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    Autoreactive CD4+ T lymphocytes are critical to the induction of autoimmune disease, but because of the degenerate nature of T cell receptor (TCR) activation such receptors also respond to other ligands. Interaction of autoreactive T cells with other non–self-ligands has been shown to activate and expand self-reactive cells and induce autoimmunity. To understand the effect on the autoreactivity of naive cross-reactive T cells of activation with a potent nonself ligand, we have generated a TCR transgenic mouse which expresses a TCR with a broad cross-reactivity to a number of ligands including self-antigen. The activation of naive transgenic recombination activating gene (Rag)2−/− T cells with a potent non–self-ligand did not result in a enhancement of reactivity to self, but made these T cells nonresponsive to the self-ligand and anti-CD3, although they retained a degree of responsiveness to the non–self-ligand. These desensitized cells had many characteristics of anergic T cells. Interleukin (IL)-2 production was selectively reduced compared with interferon (IFN)-γ. p21ras activity was reduced and p38 mitogen-activated protein kinase (MAPK) was relatively spared, consistent with known biochemical characteristics of anergy. Surprisingly, calcium fluxes were also affected and the anergic phenotype could not be reversed by exogenous IL-2. Therefore, activation with a hyperstimulating non–self-ligand changes functional specificity of an autoreactive T cell without altering the TCR. This mechanism may preserve the useful reactivity of peripheral T cells to foreign antigen while eliminating responses to self

    49 Gbit/s Direct-Modulation and Direct-Detection Transmission over 80 km SMF-28 without Optical Amplification or Filtering

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    We demonstrate direct-modulation of a discrete mode laser using Discrete Multi-Tone modulation for transmission distances up to 100 km in the 1550 nm band. A large operational temperature range (0-65ÂșC) is also demonstrated

    Optical Injection-Locked Directly-Modulated Lasers for Dispersion Pre-compensated Direct-Detection Transmission

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    The growing traffic demand in inter-data center and metro communications requires high-speed and low-cost transceivers that can flexibly adapt to different transmission distances of up to a few hundred km. Ultimately low-cost transceivers will use the simplest optical hardware: namely a directly-modulated transmitter and direct detection receiver. Using optical injection-locked directly-modulated lasers (OIL-DML), we propose a transmitter that can control the full field of the optical signal and achieve error-free transmission over up to 300 km of dispersion uncompensated SMF-28. We demonstrate such a transmission system and discuss its potential for short and medium reach communication systems

    Modulator-free quadrature amplitude modulation signal synthesis

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    The ability to generate high-speed on–off-keyed telecommunication signals by directly modulating a semiconductor laser’s drive current was one of the most exciting prospective applications of the nascent field of laser technology throughout the 1960s. Three decades of progress led to the commercialization of 2.5 Gbit s−1-per-channel submarine fibre optic systems that drove the growth of the internet as a global phenomenon. However, the detrimental frequency chirp associated with direct modulation forced industry to use external electro-optic modulators to deliver the next generation of on–off-keyed 10 Gbit s−1 systems and is absolutely prohibitive for today’s (>)100 Gbit s−1 coherent systems, which use complex modulation formats (for example, quadrature amplitude modulation). Here we use optical injection locking of directly modulated semiconductor lasers to generate complex modulation format signals showing distinct advantages over current and other currently researched solutions

    Simple geometric interpretation of signal evolution in phase-sensitive fibre optic parametric amplifier

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    Visualisation of complex nonlinear equation solutions is a useful analysis tool for various scientific and engineering applications. We have re-examined the geometrical interpretation of the classical nonlinear four-wave mixing equations for the specific scheme of a phase sensitive one-pump fiber optical parametric amplification, which has recently attracted revived interest in the optical communications due to potential low noise properties of such amplifiers. Analysis of the phase portraits of the corresponding dynamical systems provide valuable additional insight into field dynamics and properties of the amplifiers. Simple geometric approach has been proposed to describe evolution of the waves, involved in phase-sensitive fiber optical parametric amplification (PS-FOPA) process, using a Hamiltonian structure of the governing equations. We have demonstrated how the proposed approach can be applied to the optimization problems arising in the design of the specific PS-FOPA scheme. The method considered here is rather general and can be used in various applications

    Evaluation of merbarone (NSC 336628) in disseminated malignant melanoma

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    Merbarone, NSC 336628, is an investigational anticancer drug with activity against experimental animal tumors including melanoma. This paper presents results of a Phase II clinical study of merbarone in patients with biopsy proven stage IV malignant melanoma without prior chemotherapy and with no evidence of CNS involvement. Thirty-five patients with median age 58 (range 27–81), with performance status 0–2 were treated with merbarone 1000 mg/m 2 /day for five days by intravenous continuous infusion repeated every 3 weeks. All patients (21 males and 14 females) were evaluable for toxicity. Two patients were not evaluable for response having been removed from protocol treatment due to toxicity and received other treatment during the first course of chemotherapy. Among the evaluable patients there was one complete response in a supraclavicular lymph node lasting four months and one partial liver response lasting three months. The remaining thirty-one patients were non-reponders. Of these one had a stable disease lasting 21 months. The overall objective response rate was 6% (2/35) with a 95% confidence interval of 1%–19%. Twenty-six of the 35 patients have died. The estimated median survival of the entire group was 9 months with a 95% confidence interval of six to eleven months. Renal toxicity was dose-limiting and manifested as increasing serum creatinine (54% of patients), proteinuria (51%) and hematuria (9%). One patient experienced grade 4 creatinine increase, proteinuria and acute renal failure. Other toxicities included nausea (71%), vomiting (51%), malaise (23%), weakness (20%), alopecia (17%), diarrhea (17%), anorexia (14%), transaminase (SGOT, SGPT) increase (14%), constipation (14%), alkaline phosphatase or 5â€Čnucleotidase increase (9%), and fever (9%). Hematologictoxicity (granulocytopenia, leukopenia, and anemia) was generally mild and infrequent (29%, only one patient had grade 4 granulocytopenia). Overall 9 patients (26%) had at least one grade 3 toxicity. We conclude that merbarone at this dose and schedule has detectable but minimal activity in the treatment of metastatic malignant melanoma and given the significant renal toxicity this schedule does not merit further evaluation in this disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45186/1/10637_2004_Article_BF00872863.pd

    Influence of organic versus inorganic dietary selenium supplementation on the concentration of selenium in colostrum, milk and blood of beef cows

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    <p>Abstract</p> <p>Background</p> <p>Selenium (Se) is important for the postnatal development of the calf. In the first weeks of life, milk is the only source of Se for the calf and insufficient level of Se in the milk may lead to Se deficiency. Maternal Se supplementation is used to prevent this.</p> <p>We investigated the effect of dietary Se-enriched yeast (SY) or sodium selenite (SS) supplements on selected blood parameters and on Se concentrations in the blood, colostrum, and milk of Se-deficient Charolais cows.</p> <p>Methods</p> <p>Cows in late pregnancy received a mineral premix with Se (SS or SY, 50 mg Se per kg premix) or without Se (control – C). Supplementation was initiated 6 weeks before expected calving. Blood and colostrum samples were taken from the cows that had just calved (Colostral period). Additional samples were taken around 2 weeks (milk) and 5 weeks (milk and blood) after calving corresponding to Se supplementation for 6 and 12 weeks, respectively (Lactation period) for Se, biochemical and haematological analyses.</p> <p>Results</p> <p>Colostral period. Se concentrations in whole blood and colostrum on day 1 <it>post partum </it>and in colostrum on day 3 <it>post partum </it>were 93.0, 72.9, and 47.5 ÎŒg/L in the SY group; 68.0, 56.0 and 18.8 ÎŒg/L in the SS group; and 35.1, 27.3 and 10.5 ÎŒg/L in the C group, respectively. Differences among all the groups were significant (<it>P </it>< 0.01) at each sampling, just as the colostrum Se content decreases were from day 1 to day 3 in each group. The relatively smallest decrease in colostrum Se concentration was found in the SY group (<it>P </it>< 0.01).</p> <p>Lactation period. The mean Se concentrations in milk in weeks 6 and 12 of supplementation were 20.4 and 19.6 ÎŒg/L in the SY group, 8.3 and 11.9 ÎŒg/L in the SS group, and 6.9 and 6.6 ÎŒg/L in the C group, respectively. The values only differed significantly in the SS group (<it>P </it>< 0.05). The Se concentrations in the blood were similar to those of cows examined on the day of calving. The levels of glutathione peroxidase (GSH-Px) activity were 364.70, 283.82 and 187.46 ÎŒkat/L in the SY, SS, and C groups, respectively. This was the only significantly variable biochemical and haematological parameter.</p> <p>Conclusion</p> <p>Se-enriched yeast was much more effective than sodium selenite in increasing the concentration of Se in the blood, colostrum and milk, as well as the GSH-Px activity.</p
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