Debris Disks around Sun-like Stars Trilling, D. E; Bryden, G; Beichman, C. A ...
The Astrophysical journal,
02/2008, Letnik:
674, Številka:
2
Journal Article
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We have observed nearly 200 FGK stars at 24 and 70 mu m with the Spitzer Space Telescope. We identify excess infrared emission, including a number of cases where the observed flux is more than 10 ...times brighter than the predicted photospheric flux, and interpret these signatures as evidence of debris disks in those systems. We combine this sample of FGK stars with similar published results to produce a sample of more than 350 main sequence AFGKM stars. The incidence of debris disks is 4.2 super(+) sub(-) super(2) sub(1) super(.) sub(.) super(0) sub(1)% at 24 mu m for a sample of 213 Sun-like (FG) stars and 16.4 super(+) sub(2) super(2) sub(.) super(.) sub(9) super(8-)% at 70 mu m for 225 Sun-like (FG) stars. We find that the excess rates for A, F, G, and K stars are statistically indistinguishable, but with a suggestion of decreasing excess rate toward the later spectral types; this may be an age effect. The lack of strong trend among FGK stars of comparable ages is surprising, given the factor of 50 change in stellar luminosity across this spectral range. We also find that the incidence of debris disks declines very slowly beyond ages of 1 billion years.
To determine the relationship, in patients with adenocarcinoma of the colon, between survival and the number of lymph nodes analyzed from surgical specimens.
Intergroup Trial INT-0089 is a mature ...trial of adjuvant chemotherapy for high-risk patients with stage II and stage III colon cancer. We performed a secondary analysis of this group with overall survival (OS) as the main end point. Cause-specific survival (CSS) and disease-free survival were secondary end points. Rates for these outcome measures were estimated using Kaplan-Meier methodology. Log-rank test was used to compare overall curves, and Cox proportional hazards regression was used to multivariately assess predictors of outcome.
The median number of lymph nodes removed at colectomy was 11 (range, one to 87). Of the 3411 assessable patients, 648 had no evidence of lymph node metastasis. Multivariate analyses were performed on the node-positive and node-negative groups separately to ascertain the effect of lymph node removal. Survival decreased with increasing number of lymph node involvement (P =.0001 for all three survival end points). After controlling for the number of nodes involved, survival increased as more nodes were analyzed (P =.0001 for all three end points). Even when no nodes were involved, OS and CSS improved as more lymph nodes were analyzed (P =.0005 and P =.007, respectively).
The number of lymph nodes analyzed for staging colon cancers is, itself, a prognostic variable on outcome. The impact of this variable is such that it may be an important variable to include in evaluating future trials.
Neurovascular compression syndromes are usually caused by arteries that directly contact the cisternal portion of a cranial nerve. Not all cases of neurovascular contact are clinically symptomatic. ...The transition zone between the central and peripheral myelin is the most vulnerable region for symptomatic neurovascular compression syndromes. Trigeminal neuralgia (cranial nerve V) has an incidence of 4-20/100,000, a transition zone of 4 mm, with symptomatic neurovascular compression typically proximal. Hemifacial spasm (cranial nerve VII) has an incidence of 1/100,000, a transition zone of 2.5 mm, with symptomatic neurovascular compression typically proximal. Vestibular paroxysmia (cranial nerve VIII) has an unknown incidence, a transition zone of 11 mm, with symptomatic neurovascular compression typically at the internal auditory canal. Glossopharyngeal neuralgia (cranial nerve IX) has an incidence of 0.5/100,000, a transition zone of 1.5 mm, with symptomatic neurovascular compression typically proximal. The transition zone overlaps the root entry zone close to the brain stem in cranial nerves V, VII, and IX, yet it is more distal and does not overlap the root entry zone in cranial nerve VIII. Although symptomatic neurovascular compression syndromes may also occur if the neurovascular contact is outside the transition zone, symptomatic neurovascular compression syndromes are more common if the neurovascular contact occurs at the transition zone or central myelin section, in particular when associated with nerve displacement and atrophy.
Clinicians managing colorectal cancer patients need to appreciate that more than 60% of their patients are >70 years of age, and that these proportions may increase further in the future. Many will ...have co-morbidity and frailty issues and in an era of rapidly expanding therapeutic options, this may present formidable challenges. We present the SIOG updated recommendations for managing such patients.
Colorectal cancer (CRC) is one of the most commonly diagnosed cancers in Europe and worldwide, with the peak incidence in patients >70 years of age. However, as the treatment algorithms for the treatment of patients with CRC become ever more complex, it is clear that a significant percentage of older CRC patients (>70 years) are being less than optimally treated. This document provides a summary of an International Society of Geriatric Oncology (SIOG) task force meeting convened in Paris in 2013 to update the existing expert recommendations for the treatment of older (geriatric) CRC patients published in 2009 and includes overviews of the recent data on epidemiology, geriatric assessment as it relates to surgery and oncology, and the ability of older CRC patients to tolerate surgery, adjuvant chemotherapy, treatment of their metastatic disease including palliative chemotherapy with and without the use of the biologics, and finally the use of adjuvant and palliative radiotherapy in the treatment of older rectal cancer patients. An overview of each area was presented by one of the task force experts and comments invited from other task force members.
Susceptibility-weighted imaging (SWI) evolved from simple two-dimensional T2*-weighted sequences to three-dimensional sequences with improved spatial resolution and enhanced susceptibility contrast. ...SWI is an MRI sequence sensitive to compounds that distort the local magnetic field (eg, calcium and iron), in which the phase information can differentiate. But the term
is colloquially used to denote high-spatial-resolution susceptibility-enhanced sequences across different MRI vendors and sequences even when phase information is not used. The imaging appearance of SWI and related sequences strongly depends on the acquisition technique. Initially, SWI and related sequences were mostly used to improve the depiction of findings already known from standard two-dimensional T2*-weighted neuroimaging: more microbleeds in patients who are aging or with dementia or mild brain trauma; increased conspicuity of superficial siderosis in Alzheimer disease and amyloid angiopathy; and iron deposition in neurodegenerative diseases or abnormal vascular structures, such as capillary telangiectasia. But SWI also helps to identify findings not visible on standard T2*-weighted images: the nigrosome 1 in Parkinson disease and dementia with Lewy bodies, the central vein and peripheral rim signs in multiple sclerosis, the peripheral rim sign in abscesses, arterial signal loss related to thrombus, asymmetrically prominent cortical veins in stroke, and intratumoral susceptibility signals in brain neoplasms.
Three stations, at ∼80 m water depth on the Oregon shelf between 44.7°N and 43.9 N, were studied under hypoxic conditions in late spring and summer of 2009 to determine benthic oxygen consumption ...rates. Oxygen fluxes were derived from eddy correlation (EC) measurements made from an autonomous lander deployed for 11–15 h at a time. Average oxygen consumption rates ranged from 3.2 to 9.8 mmol m−2 d−1 and were highest at the southernmost station. Methods for separating eddy components and rotating coordinates were examined for effects on EC fluxes. It was found that oscillations at frequencies associated with surface and internal waves made significant contributions, but horizontal component biasing could be minimized by wave‐based rotation methods. Additional measurements included benthic boundary layer properties, and sediment permeability and profiles of sediment organic C, chlorophyll‐a, excess 210Pb and % fines. Comparative flux estimates were determined from benthic chamber measurements and microelectrode profiles at two of the stations. The chamber O2 consumption rates exceeded the EC fluxes by factors of 1.2–1.8, which may reflect enclosure effects, the different spatial and temporal scales of the measurements, and/or inhomogeneous benthic respiration rates. The magnitudes of the fluxes by either method, however, are low for shelf depths. Thus, for benthic O2 consumption to contribute to Oregon shelf hypoxia, bottom waters must be slowly renewed and minimally ventilated by along‐ or across‐shelf advection and turbulent mixing. Circulation studies indicate these conditions are favored by increased near‐bottom stratification during persistent summer upwelling‐ relaxation cycles.
Key Points
Novel eddy correlation measurements on the Oregon shelf
Surface and internal waves make significant contributions to fluxes
Low benthic oxygen consumption rates do not drive hypoxia
Efficient, low-threshold and compact semiconductor laser sources are under investigation for many applications in high-speed communications, information processing and optical interconnects. The best ...edge-emitting and vertical-cavity surface-emitting lasers have thresholds on the order of 100 µA (refs 1,2), but dissipate too much power to be practical for many applications, particularly optical interconnects. Optically pumped photonic-crystal nanocavity lasers represent the state of the art in low-threshold lasers; however, to be practical, techniques to electrically pump these structures must be developed. Here, we demonstrate a quantum-dot photonic-crystal nanocavity laser in gallium arsenide pumped by a lateral p-i-n junction formed by ion implantation. Continuous-wave lasing is observed at temperatures up to 150 K. Thresholds of only 181 nA at 50 K and 287 nA at 150 K are observed--the lowest thresholds ever observed in any type of electrically pumped laser.
Summary Background Dengue virus is the most serious mosquito-borne viral threat to public health and no vaccines or antiviral therapies are approved for dengue fever. The tetravalent DENVax vaccine ...contains a molecularly characterised live attenuated dengue serotype-2 virus (DENVax-2) and three recombinant vaccine viruses expressing the prM and E structural genes for serotypes 1, 3, and 4 in the DENVax-2 genetic backbone. We aimed to assess the safety and immunogenicity of tetravalent DENVax formulations. Methods We undertook a randomised, double-blind, phase 1, dose-escalation trial between Oct 11, 2011, and Nov 9, 2011, in the Rionegro, Antioquia, Colombia. The first cohort of participants (aged 18–45 years) were randomly assigned centrally, via block randomisation, to receive a low-dose formulation of DENvax, or placebo, by either subcutaneous or intradermal administration. After a safety assessment, participants were randomly assigned to receive a high-dose DENVax formulation, or placebo, by subcutaneous or intradermal administration. Group assignment was not masked from study pharmacists, but allocation was concealed from participants, nurses, and investigators. Primary endpoints were frequency and severity of injection-site and systemic reactions within 28 days of each vaccination. Secondary endpoints were the immunogenicity of DENVax against all four dengue virus serotypes, and the viraemia due to each of the four vaccine components after immunisation. Analysis was by intention to treat for safety and per protocol for immunogenicity. Because of the small sample size, no detailed comparison of adverse event rates were warranted. The trial is registered with ClinicalTrials.gov , number NCT01224639. Findings We randomly assigned 96 patients to one of the four study groups: 40 participants (42%) received low-dose vaccine and eight participants (8%) received placebo in the low-dose groups; 39 participants (41%) received high-dose vaccine, with nine (9%) participants assigned to receive placebo. Both formulations were well tolerated with mostly mild and transient local or systemic reactions. No clinically meaningful differences were recorded in the overall incidence of local and systemic adverse events between patients in the vaccine and placebo groups; 68 (86%) of 79 participants in the vaccine groups had solicited systemic adverse events compared with 13 (76%) of 17 of those in the placebo groups. By contrast, 67 participants (85%) in the vaccine group had local solicited reactions compared with five (29%) participants in the placebo group. Immunisation with either high-dose or low-dose DENVax formulations induced neutralising antibody responses to all four dengue virus serotypes; 30 days after the second dose, 47 (62%) of 76 participants given vaccine seroconverted to all four serotypes and 73 (96%) participants seroconverted to three or more dengue viruses. Infectious DENVax viruses were detected in only ten (25%) of 40 participants in the low-dose group and 13 (33%) of 39 participants in the high-dose group. Interpretation Our findings emphasise the acceptable tolerability and immunogenicity of the tetravalent DENVax formulations in healthy, flavivirus-naive adults. Further clinical testing of DENVax in different age groups and in dengue-endemic areas is warranted. Funding Takeda Vaccines.
Desmoid-type fibromatosis is a rare and locally aggressive monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Currently, there is no ...established or evidence-based treatment approach available for this disease. Therefore, in 2015 the European Desmoid Working Group published a position paper giving recommendations on the treatment of this intriguing disease. Here, we present an update of this consensus approach based on professionals’ AND patients’ expertise following a round table meeting bringing together sarcoma experts from the European Organization for Research and Treatment of Cancer/Soft Tissue and Bone Sarcoma Group with patients and patient advocates from Sarcoma PAtients EuroNet. In this paper, we focus on new findings regarding the prognostic value of mutational analysis in desmoid-type fibromatosis patients and new systemic treatment options.
IL-21 is the most recently discovered common gamma-chain cytokine that promotes persistent T-cell responses in chronic infections, autoimmunity and cancer. However, the therapeutic potential of ...inhibiting the IL-21-BATF signaling axis, particularly in transplant rejection, remains unclear. We used heart transplant models to examine the effects of IL-21 blockade in prevention of chronic cardiac allograft vasculopathy (CAV) using genetic knock-out and therapeutic approaches. Both wild-type C57BL/6 and IL-21-/- strains acutely rejected Balb/c skin grafts and once immunized with this skin graft, rejected Balb/c heart allografts in an accelerated fashion. However, when transplanted with heart grafts from the class-II major histocompatibility complex mutant, B6bm12 mice; wild-type recipients developed CAV, while IL-21-/- recipients were protected, even at day 100 post-transplant. Similarly, BATF-/- recipients, lacking the transcription factor BATF responsible for IL-21 production, did not develop CAV in B6-bm12 heart allografts. Strikingly, in a transient treatment protocol, the development of CAV in wild-type recipients of B6-bm12 hearts allografts was blocked by the administration of IL-21 receptor fusion protein (R-Fc). Thus, we demonstrate that CAV is regulated at least in part by IL-21 signaling and its blockade by genetic approaches or therapy with IL-21R-Fc prevents CAV in mice.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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