277 research outputs found
On the Acceptable Risk for Structures Subjected to Geohazards
Geohazards such as earthquakes or landslides represent a major risk to structures. In this contribution risk acceptance criteria for structures subjected to geohazards are reviewed. Especially the implementation of human safety and cost benefit considerations are discussed. Current trends in the definition of target safety criteria for structures subjected to earthquakes and landslides are presented and conclusions regarding codified criteria are drawn
Dendrimer-aktivierte Chipmatrix für die Herstellung von Nukleinsäure- und Protein-Microarrays
Für die Herstellung von Microarrays durch Immobilisierung bioorganischer Sondenmoleküle, wie DNA-Fragmente oder Proteine, mittels automatisierter Dispenser- oder Plottersysteme werden modifizierte Oberflächen benötigt, die eine physikalische oder chemische Bindung zum Biomolekül ausbilden können. Als Trägermaterial für die Herstellung von Microarrays hat sich aufgrund seiner hohen mechanischen und chemischen Stabilität, sowie seiner geringen Eigenfluoreszenz Glas bewährt. Damit Biochip-basierte Analysen reproduzierbar und mit hoher Nachweisempfindlichkeit durchgeführt werden können, ist es unabdingbar, daß die Modifikation einerseits homogen über die gesamte Chipoberfläche verläuft und andererseits eine hohe Dichte aktiver Kopplungsstellen für das Sondenmolekül bereitstellt. Desweiteren ist es wünschenswert, daß einmal eingesetzte Microarrays durch Regeneration wiederverwendet werden können. Zur Zeit gängige Verfahren, wie z. B. das UV-induzierte Crosslinking an amino-funktionalisierte oder polyamidbeschichtete Trägersysteme, sowie die Chemisorption thiolierter Verbindungen an Gold weisen diesbezüglich erhebliche Defizite auf. Verbesserte Eigenschaften lassen sich erzielen, wenn die Immobilisierung kovalent über ein Linkersystem zwischen Trägermaterial und Biomolekül erfolgt. Wir berichten hier über ein Modifikationsverfahren, das durch den Aufbau einer dendritischen Polymerschicht eine hocheffiziente, kovalente Immobilisierung von Sondenmolekülen erlaubt
Vector and Tensor Analyzing Powers of the H(d,gamma)He-3 capture reaction
Precise measurements of the deuteron vector analyzing power Ayd and the
tensor analyzing power Ayy of the H(d,gamma)He-3 capture reaction have been
performed at deuteron energies of 29MeV and 45MeV. The data have been compared
to theoretical state-of-the-art calculations available today. Due to the large
sensitivity of polarization observables and the precision of the data light
could be shed on small effects present in the dynamics of the reaction.Comment: 11 pages, 24 figures, submitted for publication to PRC, revised after
referee proces
Precise Neutron Magnetic Form Factors
Precise data on the neutron magnetic form factor G_{mn} have been obtained
with measurements of the ratio of cross sections of D(e,e'n) and D(e,e'p) up to
momentum transfers of Q^2 = 0.9 (GeV/c)^2. Data with typical uncertainties of
1.5% are presented. These data allow for the first time to extract a precise
value of the magnetic radius of the neutron.Comment: 10 pages, 2 figures, submitted to Physics Letters
A Measurement of the Electric Form Factor of the Neutron through at (GeV/c)
We report the first measurement of the neutron electric form factor
via using a solid polarized target. was
determined from the beam-target asymmetry in the scattering of longitudinally
polarized electrons from polarized deuterated ammonia, ND. The
measurement was performed in Hall C at Thomas Jefferson National Accelerator
Facility (TJNAF) in quasi free kinematics with the target polarization
perpendicular to the momentum transfer. The electrons were detected in a
magnetic spectrometer in coincidence with neutrons in a large solid angle
segmented detector. We find at (GeV/c).Comment: Latex2e 5 pages, 3 figure
IVF for premature ovarian failure: first reported births using oocytes donated from a twin sister
BACKGROUND: Premature ovarian failure (POF) remains a clinically challenging entity because in vitro fertilisation (IVF) with donor oocytes is currently the only treatment known to be effective.
METHODS: A 33 year-old nulligravid patient with a normal karyotype was diagnosed with POF; she had a history of failed fertility treatments and had an elevated serum FSH (42 mIU/ml). Oocytes donated by her dizygotic twin sister were used for IVF. The donor had already completed a successful pregnancy herself and subsequently produced a total of 10 oocytes after a combined FSH/LH superovulation regime. These eggs were fertilised with sperm from the recipient\u27s husband via intracytoplasmic injection and two fresh embryos were transferred to the recipient on day three.
RESULTS: A healthy twin pregnancy resulted from IVF; two boys were delivered by caesarean section at 39 weeks\u27 gestation. Additionally, four embryos were cryopreserved for the recipient\u27s future use. The sister-donor achieved another natural pregnancy six months after oocyte retrieval, resulting in a healthy singleton delivery.
CONCLUSION: POF is believed to affect approximately 1% of reproductive age females, and POF patients with a sister who can be an oocyte donor for IVF are rare. Most such IVF patients will conceive from treatment using oocytes from an anonymous oocyte donor. This is the first report of births following sister-donor oocyte IVF in Ireland. Indeed, while sister-donor IVF has been successfully undertaken by IVF units elsewhere, this is the only known case where oocyte donation involved twin sisters. As with all types of donor gamete therapy, pre-treatment counselling is important in the circumstance of sister oocyte donation
Measurement of the asymmetries in 3(¯e, e′p)d and 3(¯e, e′p)np
Abstract.: The electron target asymmetries A || and A⊥ with target spin parallel and perpendicular to the momentum transfer \ensuremath{\boldsymbol{q}} were measured for both the two- and three-body breakup of 3He in the 3 (¯e, e'p)-reaction. Polarized electrons were scattered off polarized 3He in the quasielastic regime in parallel kinematics with the scattered electron and the knocked-out proton detected using the Three-Spectrometer Facility at MAMI. The results are compared to Faddeev calculations which take into account Final-State Interactions as well as Meson Exchange Currents. The experiment confirms the prediction of a large effect of Final-State Interactions in the asymmetry of the three-body breakup and of an almost negligible one for the two-body breaku
The outcomes of patients with very small coronary artery disease treated with thin strut cobalt chromium bare metal stents: an observational study
A controlled trial of rivaroxaban after transcatheter aortic-valve replacement
Background: whether the direct factor Xa inhibitor rivaroxaban can prevent thromboembolic events after transcatheter aortic-valve replacement (TAVR) is unclear. Methods: we randomly assigned 1644 patients without an established indication for oral anticoagulation after successful TAVR to receive rivaroxaban at a dose of 10 mg daily (with aspirin at a dose of 75 to 100 mg daily for the first 3 months) (rivaroxaban group) or aspirin at a dose of 75 to 100 mg daily (with clopidogrel at a dose of 75 mg daily for the first 3 months) (antiplatelet group). The primary efficacy outcome was the composite of death or thromboembolic events. The primary safety outcome was major, disabling, or life-threatening bleeding. The trial was terminated prematurely by the data and safety monitoring board because of safety concerns. Results: after a median of 17 months, death or a first thromboembolic event (intention-to-treat analysis) had occurred in 105 patients in the rivaroxaban group and in 78 patients in the antiplatelet group (incidence rates, 9.8 and 7.2 per 100 person-years, respectively; hazard ratio with rivaroxaban, 1.35; 95% confidence interval [CI], 1.01 to 1.81; P = 0.04). Major, disabling, or life-threatening bleeding (intention-to-treat analysis) had occurred in 46 and 31 patients, respectively (4.3 and 2.8 per 100 person-years; hazard ratio, 1.50; 95% CI, 0.95 to 2.37; P = 0.08). A total of 64 deaths occurred in the rivaroxaban group and 38 in the antiplatelet group (5.8 and 3.4 per 100 person-years, respectively; hazard ratio, 1.69; 95% CI, 1.13 to 2.53). Conclusions: in patients without an established indication for oral anticoagulation after successful TAVR, a treatment strategy including rivaroxaban at a dose of 10 mg daily was associated with a higher risk of death or thromboembolic complications and a higher risk of bleeding than an antiplatelet-based strategy. (Funded by Bayer and Janssen Pharmaceuticals; GALILEO ClinicalTrials.gov number, NCT02556203.)
Use of a Repositionable and Fully Retrievable Aortic Valve in Routine Clinical Practice: The RESPOND Study and RESPOND Extension Cohort
Objectives: The authors sought to evaluate 1-year clinical outcomes with the Lotus valve (Boston Scientific, Marlborough, Massachusetts) in a large international, multicenter prospective registry including patients eligible for transcatheter aortic valve replacement (TAVR) based on heart team consensus. Background: TAVR is a safe and effective treatment for severe aortic valve stenosis; however, limited data are available on TAVR with the repositionable and fully retrievable Lotus valve in unrestricted contemporary clinical practice. Methods: The RESPOND (Repositionable Lotus Valve System—Post-Market Evaluation of Real World Clinical Outcomes) study enrolled 1,014 patients; 996 patients were implanted with the Lotus valve (mean age 80.8 years, 50.8% female, mean STS score 6.0 ± 6.9%). The primary endpoint was all-cause mortality in the intent-to-treat population at 30 days and 1 year. An Extension cohort of 50 patients was treated with the Lotus valve with Depth Guard including a modified delivery system. Mortality and stroke were independently adjudicated. An independent core laboratory assessed echocardiographic data. Results: One-year clinical follow-up was available for 99.9% of Lotus valve-treated patients. At 1 year, the all-cause mortality rate was 11.7% and 4.1% of patients had experienced a disabling stroke. The permanent pacemaker implantation rate was 32% (37% among pacemaker-naive patients). Echocardiographic data at 1 year were available for core laboratory assessment in 62.6% of patients. Paravalvular leak was absent or trace in 94.5%, mild in 5.1%, and moderate in 0.4% of patients. Data from the Extension cohort confirmed good clinical outcomes at 30 days with an 18% permanent pacemaker rate (20% among pacemaker-naive patients). Conclusions: One-year outcomes from the RESPOND study confirm the safety and efficacy of the Lotus valve when used in routine clinical practice. (Repositionable Lotus Valve System—Post-Market Evaluation of Real World Clinical Outcomes [RESPOND]; NCT02031302
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