SPECACT, a fortran program for the routine calculation of the specific activity of fission-produced Molybdenum-99.

The specific activity of 99 Mo is an important factor in the production of 99 Mo/Tc-99m generators used in nuclear medicine. Molybdenum-99 formed via the fission route is not carrier free but is contaminated by a number of stable molybdenum isotopes formed concurrently during neutron irradiation of the uranium target. The specific activity of fission-based 99 Mo is therefore a function of irradiation time and post-irradiation decay. A computer program written in FORTRAN is presented for defining routinely the specific activity of fission-based 99 Mo

Development of a pilot plant for the removal of rhenium from molybdenum trioxide.

Reagent grade molybdenum trioxide used as a target material for the preparation of Tc-99m pharmaceuticals contains trace amounts of rhenium. A simple charcoal adsorptions process has been developed to remove rhenium selectively from molybdenum before neutron irradiation. Details are given of the design and operation of a pilot plant in which 17 kg of molybdenum trioxide was produced having a rhenium content of less than 1 x 10 -6 mu g g -1. Although contamination of the Tc-99m by inactive rhenium and 188 Re was effectively eliminated 188 Re resulting from the irradiation of tungsten impurity in the molybdenum trioxide target was still present

A Sparse Stress Model

Force-directed layout methods constitute the most common approach to draw general graphs. Among them, stress minimization produces layouts of comparatively high quality but also imposes comparatively high computational demands. We propose a speed-up method based on the aggregation of terms in the objective function. It is akin to aggregate repulsion from far-away nodes during spring embedding but transfers the idea from the layout space into a preprocessing phase. An initial experimental study informs a method to select representatives, and subsequent more extensive experiments indicate that our method yields better approximations of minimum-stress layouts in less time than related methods.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

Oncocytic carcinoma of the parotid gland with late cervical lymph node metastases: a case report

<p>Abstract</p> <p>Introduction</p> <p>Oncocytic carcinoma is a rare proliferation of cytomorphologically malignant oncocytes mainly found in glandular tissue, accounting for 0.5% of all epithelial salivary gland malignancies and 0.18% of all epithelial salivary gland tumors.</p> <p>Case presentation</p> <p>We report a case of oncocytic carcinoma arising in the parotid gland of a 65-year-old Caucasian man. Our patient initially underwent left superficial parotidectomy, including the removal of the mass. A close follow-up was made, and four years after first surgery cervical lymph node metastases were confirmed. Therefore, a complete parotidectomy and radical neck dissections were performed. There were no complications and no sign of recurrence after six months of follow-up.</p> <p>Conclusion</p> <p>Oncocytic carcinoma is an extremely rare malignancy in the salivary glands. Prophylactic neck dissection may be indicated for tumors larger than 2 cm in diameter (our patient's tumor was 2.5 cm at its greatest diameter). The clinical course of our patient, with the appearance of cervical lymph node metastases after four years of follow-up, supports this approach. Further investigation of the prognosis and correct treatment of patients with oncocytic carcinoma are required as more cases are reported.</p

High-density information storage in an absolutely defined aperiodic sequence of monodisperse copolyester

Synthesis of a polymer composed of a large discrete number of chemically distinct monomers in an absolutely defined aperiodic sequence remains a challenge in polymer chemistry. The synthesis has largely been limited to oligomers having a limited number of repeating units due to the difficulties associated with the step-by-step addition of individual monomers to achieve high molecular weights. Here we report the copolymers of ??-hydroxy acids, poly(phenyllactic-co-lactic acid) (PcL) built via the cross-convergent method from four dyads of monomers as constituent units. Our proposed method allows scalable synthesis of sequence-defined PcL in a minimal number of coupling steps from reagents in stoichiometric amounts. Digital information can be stored in an aperiodic sequence of PcL, which can be fully retrieved as binary code by mass spectrometry sequencing. The information storage density (bit/Da) of PcL is 50% higher than DNA, and the storage capacity of PcL can also be increased by adjusting the molecular weight (~38???kDa)

Description and evaluation of a bench porcine model for teaching surgical residents vascular anastomosis skills

<p>Abstract</p> <p>Background</p> <p>Numerous models, of variable quality, exist to impart the complex skills required to perform vascular anastomosis. These models differ with regard to the kinds of materials used, as well as their sizes, the time needed for their preparation, their availability, and the associated costs. The present study describes a bench model that uses formalin-fixed porcine aorta, and its evaluation by young surgical residents during a recent skills course.</p> <p>Findings</p> <p>The aortic segments used were a by-product of slaughtering. They were fixed and stored after harvesting for eventual use. Ten young surgical residents participated, and each performed one end-to-side vascular anastomosis. The evaluation was a questionnaire maintaining anonymity of the participant containing questions addressing particular aspects of the model and the experiences of the trainee, along with their ratings concerning the need for a training course to learn vascular anastomosis techniques. The scoring on the survey was done using a global 6-point rating scale (Likert Scale). In addition, we ranked the present model by reviewing the current literature for models that address vascular anastomosis skills.</p> <p>The trainees who participated were within their first two years of training (1.25 ± 0.46). A strong agreement in terms of the necessity of training for vascular anastomosis techniques was evident among the participating trainees (5.90 ± 0.32), who had only few prior manual experiences (total number 1.50 ± 0.53). The query revealed a strong agreement that porcine aorta is a suitable model that fits the needs for training vascular anastomosis skills (5.70 ± 0.48). Only a few bench models designed to teach surgical residents vascular anastomosis techniques were available in the literature.</p> <p>Conclusions</p> <p>The preparatory and financial resources needed to perform anastomosis skills training using porcine aorta are few. The presented bench model appears to be appropriate for learning vascular anastomosis skills, as rated by the surgical trainees themselves.</p

The effect of positively framing side-effect risk in two different formats on side-effect expectations, informed consent and credibility: A randomised trial of 16- to 75-year-olds in England

Introduction Reframing side-effect information in patient information leaflets (PILs) in terms of those who remain side-effect–free may reduce negative expectations and side-effects, although there are concerns this may impact informed consent. This study compared two versions of positively framed PILs with current practice to see which reduces side-effect expectations whilst maintaining informed consent and credibility. Methods We commissioned Ipsos MORI to conduct an online survey of 16- to 75-year-olds in England. 1067 people completed the study and were randomised to receive a PIL for a hypothetical new antibiotic that either communicated side-effects following current practice (n = 356), used positive framing with natural frequencies (n = 356), or positive framing with percentages (n = 355). After reading the leaflet, participants completed measures of their side-effect expectations, absolute risk perceptions, and satisfaction and credibility of the leaflet. Results Both positively framed PILs resulted in significantly lower side-effect expectations compared with the current PIL for all side-effects (ps  0.626). The positively framed PIL using natural frequencies produced more accurate risk perceptions than the same leaflet using percentages; but performed equally to the current PIL. There was no difference between the leaflets in terms of satisfaction with or credibility of the PILs. Conclusion Positively framed PILs using natural frequencies significantly reduced side-effect expectations and provided the most accurate risk perceptions without impacting satisfaction or credibility. Replication is needed with patients prescribed new medication and those with lower educational status

Transit Timing and Duration Variations for the Discovery and Characterization of Exoplanets

Transiting exoplanets in multi-planet systems have non-Keplerian orbits which can cause the times and durations of transits to vary. The theory and observations of transit timing variations (TTV) and transit duration variations (TDV) are reviewed. Since the last review, the Kepler spacecraft has detected several hundred perturbed planets. In a few cases, these data have been used to discover additional planets, similar to the historical discovery of Neptune in our own Solar System. However, the more impactful aspect of TTV and TDV studies has been characterization of planetary systems in which multiple planets transit. After addressing the equations of motion and parameter scalings, the main dynamical mechanisms for TTV and TDV are described, with citations to the observational literature for real examples. We describe parameter constraints, particularly the origin of the mass/eccentricity degeneracy and how it is overcome by the high-frequency component of the signal. On the observational side, derivation of timing precision and introduction to the timing diagram are given. Science results are reviewed, with an emphasis on mass measurements of transiting sub-Neptunes and super-Earths, from which bulk compositions may be inferred.Comment: Revised version. Invited review submitted to 'Handbook of Exoplanets,' Exoplanet Discovery Methods section, Springer Reference Works, Juan Antonio Belmonte and Hans Deeg, Eds. TeX and figures may be found at https://github.com/ericagol/TTV_revie