293 research outputs found

    Absolute flux measurements for swift atoms

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    While a torsion balance in vacuum can easily measure the momentum transfer from a gas beam impinging on a surface attached to the balance, this measurement depends on the accommodation coefficients of the atoms with the surface and the distribution of the recoil. A torsion balance is described for making absolute flux measurements independent of recoil effects. The torsion balance is a conventional taut suspension wire design and the Young modulus of the wire determines the relationship between the displacement and the applied torque. A compensating magnetic field is applied to maintain zero displacement and provide critical damping. The unique feature is to couple the impinging gas beam to the torsion balance via a Wood's horn, i.e., a thin wall tube with a gradual 90 deg bend. Just as light is trapped in a Wood's horn by specular reflection from the curved surfaces, the gas beam diffuses through the tube. Instead of trapping the beam, the end of the tube is open so that the atoms exit the tube at 90 deg to their original direction. Therefore, all of the forward momentum of the gas beam is transferred to the torsion balance independent of the angle of reflection from the surfaces inside the tube

    Application and flight test of linearizing transformations using measurement feedback to the nonlinear control problem

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    The design of nonlinear controllers has relied on the use of detailed aerodynamic and engine models that must be associated with the control law in the flight system implementation. Many of these controllers were applied to vehicle flight path control problems and have attempted to combine both inner- and outer-loop control functions in a single controller. An approach to the nonlinear trajectory control problem is presented. This approach uses linearizing transformations with measurement feedback to eliminate the need for detailed aircraft models in outer-loop control applications. By applying this approach and separating the inner-loop and outer-loop functions two things were achieved: (1) the need for incorporating detailed aerodynamic models in the controller is obviated; and (2) the controller is more easily incorporated into existing aircraft flight control systems. An implementation of the controller is discussed, and this controller is tested on a six degree-of-freedom F-15 simulation and in flight on an F-15 aircraft. Simulation data are presented which validates this approach over a large portion of the F-15 flight envelope. Proof of this concept is provided by flight-test data that closely matches simulation results. Flight-test data are also presented

    Macroscopic Hematuria—A Leading Urological Problem in Patients on Anticoagulant Therapy: Is the Common Diagnostic Standard Still Advisable?

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    All urological standards of care are based on the past definition of the clinical importance of macroscopic hematuria. The aim of the study was to assess the phenomenon of iatrogenic hematuria in current clinical practice and analyze its origins in patients receiving anticoagulant drugs. Retrospective analysis of clinical documentation of 238 patients that were consulted for hematuria in 2007–2009 by 5 consultant urologists was performed. In the group of 238 patients with hematuria, 155 (65%) received anticoagulants. Abnormalities of urinary tract were found in 45 (19%) patients. Estimated cost of a single neoplasm detection reached the value of 3252 Euro (mean 3-day hospitalization). The strong correlation between the presence of hematuria and anticoagulant treatment was observed. Authors suggest to redefine the present and future role of hematuria from a standard manifestation of serious urological disease to a common result of a long-term anticoagulant therapy

    Technique of transurethral needle core biopsy to confirm invasive bladder cancer staging

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    Introduction: Transurethral, cystoscopically-guided needle core biopsy (TUcoreBxBT) seems to be a less invasive diagnostic method than transurethral resection (TURBT) offering a simple way to confirm cancer infiltration of the bladder. The aim of this study was to assess the technique of TUcoreBxBT in the diagnosis of bladder cancer infiltrating the detrusor muscle. Material and methods: In every 96 pts the suspicion of invasive bladder cancer (IBC) was evaluated on the basis of radiological examinations, cystoscopy and bimanual examination. TUcoreBxBT were performed using a rigid cystoscope with a direct working channel and tru-cut automatic (COOK Quick-Core® BiopsyNeedle) 18 G/480 mm needle or self construction tru-cut 16 G/400 mm needle, adapted to work with a standard biopsy gun. At least three cores were taken in each patient, followed by regular TURBT. Results: There were no complications of the bladder biopsy procedure. The average size of cores was 15 mm (8-17 mm). In every case TUcoreBxBT revealed muscle infiltration and was in agreement with all microscopic examinations of TURBT. Conclusions: TUcoreBxBT in cases of clear suspicion of invasive bladder cancer is a simple, short and safe procedure which makes it possible to collect reliable material for microscopic examination. TUcoreBxBT is less invasive than standard TURBT only in diagnosis and staging of invasive tumours, and seems to be effective in selected cases to confirm malignancy before radical cystectom

    Renal carcinoma infiltrating inferior vena cava and combined valvular heart disease - one-stage uro-cardiological procedure: a case report

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    Standard treatment of patients with coexisting cardiac and non-cardiac diseases includes two separate operations. We report a case of 55-year-old man with combined valvular heart disease and renal carcinoma infiltrating inferior caval vein, who underwent one-stage cardio-urologic procedure. In the first step, mitral and tricuspid valvuloplasty were performed by cardiac surgeons. Then, urologists performed radical nephrectomy and thrombectomy. The postoperative course was uneventful. In twelve months follow-up the patient shows no signs of reccurrence and he had no symptoms of cardiac disease. To the best of our knowledge such a case has never been reported before in the literature

    A high flux source of swift oxygen atoms

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    A source of swift oxygen atoms is described which has several unique features. A high current ion beam is produced by a microwave discharge, accelerated to 10 keV and the mass selected by a modified Du Pont 21-110 mass spectrometer. The O(+) beam exciting the mass spectrometer is focused into a rectangular shape with an energy spread of less than 1 eV. The next section of the machine decelerates the ion beam into a counterpropagating electron beam in order to minimize space charge effects. After deceleration, the ion beam intersects at 90 deg, a neutral oxygen atom beam, which via resonant charge exchange produces a mixture of O(+) and O. Any remaining O(+) are swept out of the beam by an electric field and differentially pumped away while the desired O beam, collimated by slits, impinges on the target. In situ monitoring of the target surface is done by X-ray photoelectron or Auger spectroscopy. Faraday cups provide flux measurements in the ion sections while the neutral flux is determined by a special torsion balance or by a quadrupole mass spectrometer specially adapted for swift atoms. While the vacuum from the source through the mass spectrometer is maintained by diffusion pumps, the rest of the machine is UHV

    Geldanamycin-induced osteosarcoma cell death is associated with hyperacetylation and loss of mitochondrial pool of heat shock protein 60 (hsp60)

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    Osteosarcoma is one of the most malignant tumors of childhood and adolescence that is often resistant to standard chemo- and radio-therapy. Geldanamycin and geldanamycin analogs have been recently studied as potential anticancer agents for osteosarcoma treatment. Here, for the first time, we have presented novel anticancer mechanisms of geldanamycin biological activity. Moreover, we demonstrated an association between the effects of geldanamycin on the major heat shock proteins (HSPs) and the overall survival of highly metastatic human osteosarcoma 143B cells. We demonstrated that the treatment of 143B cells with geldanamycin caused a subsequent upregulation of cytoplasmic Hsp90 and Hsp70 whose activity is at least partly responsible for cancer development and drug resistance. On the other hand, geldanamycin induced upregulation of Hsp60 gene expression, and a simultaneous loss of hyperacetylated Hsp60 mitochondrial protein pool resulting in decreased viability and augmented cancer cell death. Hyperacetylation of Hsp60 seems to be associated with anticancer activity of geldanamycin. In light of the fact that mitochondrial dysfunction plays a critical role in the apoptotic signaling pathway, the presented data may support a hypothesis that Hsp60 can be another functional part of mitochondria-related acetylome being a potential target for developing novel anticancer strategies

    Net Charge on a Noble Gas Atom Adsorbed on a Metallic Surface

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    Adsorbed noble gas atoms donate (on the average) a fraction of an electronic charge to the substrate metal. The effect has been experimentally observed as an adsorptive change in the electronic work function. The connection between the effective net atomic charge and the binding energy of the atom to the metal is theoretically explored.Comment: ReVvTeX 3.1 format, Two Figures, Three Table

    Growth, body composition, and cardiovascular and nutritional risk of 5- to 10-y-old children consuming vegetarian, vegan, or omnivore diets.

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    BACKGROUND: Plant-based diets (PBDs) are increasingly recommended for human and planetary health. However, comprehensive evidence on the health effects of PBDs in children remains incomplete, particularly in vegans. OBJECTIVES: To quantify differences in body composition, cardiovascular risk, and micronutrient status of vegetarian and vegan children relative to omnivores and to estimate prevalence of abnormal micronutrient and cholesterol status in each group. METHODS: In a cross-sectional study, Polish children aged 5-10 y (63 vegetarian, 52 vegan, 72 matched omnivores) were assessed using anthropometry, deuterium dilution, DXA, and carotid ultrasound. Fasting blood samples, dietary intake, and accelerometry data were collected. RESULTS: All results are reported relative to omnivores. Vegetarians had lower gluteofemoral adiposity but similar total fat and lean mass. Vegans had lower fat indices in all regions but similar lean mass. Both groups had lower bone mineral content (BMC). The difference for vegetarians attenuated after accounting for body size but remained in vegans (total body minus the head: -3.7%; 95% CI: -7.0, -0.4; lumbar spine: -5.6%; 95% CI: -10.6, -0.5). Vegetarians had lower total cholesterol, HDL, and serum B-12 and 25-hydroxyvitamin D [25(OH)D] without supplementation but higher glucose, VLDL, and triglycerides. Vegans were shorter and had lower total LDL (-24 mg/dL; 95% CI: -35.2, -12.9) and HDL (-12.2 mg/dL; 95% CI: -17.3, -7.1), high-sensitivity C-reactive protein, iron status, and serum B-12 (-217.6 pmol/L; 95% CI: -305.7, -129.5) and 25(OH)D without supplementation but higher homocysteine and mean corpuscular volume. Vitamin B-12 deficiency, iron-deficiency anemia, low ferritin, and low HDL were more prevalent in vegans, who also had the lowest prevalence of high LDL. Supplementation resolved low B-12 and 25(OH)D concentrations. CONCLUSIONS: Vegan diets were associated with a healthier cardiovascular risk profile but also with increased risk of nutritional deficiencies and lower BMC and height. Vegetarians showed less pronounced nutritional deficiencies but, unexpectedly, a less favorable cardiometabolic risk profile. Further research may help maximize the benefits of PBDs in children
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