900 research outputs found
Edge contribution to forward scattering by spheres
Edge functions T1 and T2, which describe the polarization-dependent edge contribution to forward scattering by spheres, are derived from the exact Mie solution. All the relative refractive indices and the 64 , x , 2048 size parameter range are considered. The edge functions significantly improve the approximation methods that can be used to calculate forward-scattering patterns. For m close to 1, an asymptotic approximation is used. Otherwise, the familiar geometrical optics approximation and the similar physical optics approximation for glory rays are used. Both geometrical and physical optics equations can be deduced from the above-mentioned asymptotic approximation
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Aims—To investigate whether the analysis of immunoglobulin (Ig)/T cell receptor (TCR) rearrangements is useful in the diagnosis of lymphoproliferative disorders. Methods—In a series of 107 consecutive cases with initial suspicion of non-Hodgkin's lymphoma (NHL), Southern blot (SB) analysis of Ig/TCR rearrangements was performed. Results—In 98 of 100 histopathologically conclusive cases, Ig/TCR gene results were concordant. In one presumed diffuse large B cell lymphoma (DLCL) and one follicular lymphoma (FL) case no clonality could be detected by SB analysis, or by polymerase chain reaction (PCR) at second stage. In the DLCL, sampling error might have occurred; the FL was revised after an initial diagnosis of reactivity. In many of the histopathologically inconclusive cases Ig/TCR gene SB analysis was helpful, giving support for the histopathological suspicion. However, because of a lack of (clinical) follow up data this could not be confirmed in a few cases. Conclusions—Experienced haematopathologists or a pathologist panel can diagnose malignant versus reactive lesions in most cases without the need for Ig/TCR gene analysis and can select the 5–10% of cases that might benefit from molecular clonality studies. Key Words: B cell lymphoma • immunoglobulin and T cell receptor genes • clonality analysis • Southern blottin
Ices in the edge-on disk CRBR 2422.8-3423: Spitzer spectroscopy and Monte Carlo radiative transfer modeling
We present 5.2-37.2 micron spectroscopy of the edge-on circumstellar disk
CRBR 2422.8-3423 obtained using the InfraRed Spectrograph (IRS) of the Spitzer
Space Telescope. The IRS spectrum is combined with ground-based 3-5 micron
spectroscopy to obtain a complete inventory of solid state material present
along the line of sight toward the source. We model the object with a 2D
axisymmetric (effectively 3D) Monte Carlo radiative transfer code. It is found
that the model disk, assuming a standard flaring structure, is too warm to
contain the very large observed column density of pure CO ice, but is possibly
responsible for up to 50% of the water, CO2 and minor ice species. In
particular the 6.85 micron band, tentatively due to NH4+, exhibits a prominent
red wing, indicating a significant contribution from warm ice in the disk. It
is argued that the pure CO ice is located in the dense core Oph-F in front of
the source seen in the submillimeter imaging, with the CO gas in the core
highly depleted. The model is used to predict which circumstances are most
favourable for direct observations of ices in edge-on circumstellar disks. Ice
bands will in general be deepest for inclinations similar to the disk opening
angle, i.e. ~70 degrees. Due to the high optical depths of typical disk
mid-planes, ice absorption bands will often probe warmer ice located in the
upper layers of nearly edge-on disks. The ratios between different ice bands
are found to vary by up to an order of magnitude depending on disk inclination
due to radiative transfer effects caused by the 2D structure of the disk.
Ratios between ice bands of the same species can therefore be used to constrain
the location of the ices in a circumstellar disk. [Abstract abridged]Comment: 49 pages, accepted for publication in Ap
Hysterectomy Does Not Cause Constipation
PURPOSE: This study was designed to evaluate the risk on development and persistence of constipation after hysterectomy. METHODS: We conducted a prospective, observational, multicenter study with three-year follow-up in 13 teaching and nonteaching hospitals in the Netherlands. A total of 413 females who underwent hysterectomy for benign disease other than symptomatic uterine prolapse were included. All patients underwent vaginal hysterectomy, subtotal abdominal hysterectomy, or total abdominal hysterectomy. A validated disease-specific quality-of-life questionnaire was completed before and three years after surgery to assess the presence of constipation. RESULTS: Of the 413 included patients, 344 (83 percent) responded at three-year follow-up. Constipation had developed in 7 of 309 patients (2 percent) without constipation before surgery and persisted in 16 of 35 patients (46 percent) with constipation before surgery. Preservation of the cervix seemed to be associated with an increased risk of the development of constipation (relative risk, 6.6; 95 percent confidence interval, 1.3-33.3; P=0.02). Statistically significant risk factors for the persistence of constipation could not be identified. CONCLUSIONS: Hysterectomy does not seem to cause constipation. In nearly half of the patients reporting constipation before hysterectomy, this symptom will disappear
DNA Nucleobase Synthesis at Titan Atmosphere Analog by Soft X-rays
Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of
N2 and CH4 and includes traces of many simple organic compounds. This
atmosphere also partly consists of haze and aerosol particles which during the
last 4.5 gigayears have been processed by electric discharges, ions, and
ionizing photons, being slowly deposited over the Titan surface. In this work,
we investigate the possible effects produced by soft X-rays (and secondary
electrons) on Titan aerosol analogs in an attempt to simulate some prebiotic
photochemistry. The experiments have been performed inside a high vacuum
chamber coupled to the soft X-ray spectroscopy beamline at the Brazilian
Synchrotron Light Source, Campinas, Brazil. In-situ sample analyses were
performed by a Fourier transform infrared spectrometer. The infrared spectra
have presented several organic molecules, including nitriles and aromatic CN
compounds. After the irradiation, the brownish-orange organic residue (tholin)
was analyzed ex-situ by gas chromatographic (GC/MS) and nuclear magnetic
resonance (1H NMR) techniques, revealing the presence of adenine (C5H5N5), one
of the constituents of the DNA molecule. This confirms previous results which
showed that the organic chemistry on the Titan surface can be very complex and
extremely rich in prebiotic compounds. Molecules like these on the early Earth
have found a place to allow life (as we know) to flourish.Comment: To appear in Journal of Physical Chemistry A.; Number of pages: 6;
Number of Figures: 5; Number of Tables: 1; Number of references:49; Full
paper at http://pubs.acs.org/doi/abs/10.1021/jp902824
Can we <i>S</i>ave the rectum by watchful waiting or <i>T</i>rans<i>A</i>nal microsurgery following (chemo) <i>R</i>adiotherapy versus total mesorectal excision for early <i>RE</i>ctal <i>C</i>ancer (STAR-TREC study)?::protocol for a multicentre, randomised feasibility study
Introduction Total mesorectal excision (TME) is the highly effective standard treatment for rectal cancer but is associated with significant morbidity and may be overtreatment for low-risk cancers. This study is designed to determine the feasibility of international recruitment in a study comparing organ-saving approaches versus standard TME surgery. Methods and analysis STAR-TREC trial is a multicentre international randomised, three-arm parallel, phase II feasibility study in patients with biopsy-proven adenocarcinoma of the rectum. The trial is coordinated from Birmingham, UK with national hubs in Radboudumc (the Netherlands) and Odense University Hospital Svendborg UMC (Denmark). Patients with rectal cancer, staged by CT and MRI as ≤cT3b (up to 5 mm of extramural spread) N0 M0 can be included. Patients will be randomised to either standard TME surgery (control), organ-saving treatment using long-course concurrent chemoradiation or organ-saving treatment using short-course radiotherapy. For patients treated with an organ-saving strategy, clinical response to (chemo)radiotherapy determines the next treatment step. An active surveillance regime will be performed in the case of a complete clinical regression. In the case of incomplete clinical regression, patients will proceed to local excision using an optimised platform such as transanal endoscopic microsurgery or other transanal techniques (eg, transanal endoscopic operation or transanal minimally invasive surgery). The primary endpoint of this phase II study is to demonstrate sufficient international recruitment in order to sustain a phase III study incorporating pelvic failure as the primary endpoint. Success in phase II is defined as randomisation of at least four cases per month internationally in year 1, rising to at least six cases per month internationally during year 2
Association of elevated fractional exhaled nitric oxide concentration and blood eosinophil count with severe asthma exacerbations
Blood eosinophil count (BEC) and fractional exhaled nitric oxide (FeNO) concentration are established biomarkers in asthma, associated particularly with the risk of exacerbations. We evaluated the relationship of BEC and FeNO as complementary and independent biomarkers of severe asthma exacerbations.This article is freely available via Open Access. Click on the Publisher URL to access the full-text
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