Technical Note: In silico and experimental evaluation of two leaf-fitting algorithms for MLC tracking based on exposure error and plan complexity.

PURPOSE: Multileaf collimator (MLC) tracking is being clinically pioneered to continuously compensate for thoracic and pelvic motion during radiotherapy. The purpose of this work was to characterize the performance of two MLC leaf-fitting algorithms, direct optimization and piecewise optimization, for real-time motion compensation with different plan complexity and tumor trajectories. METHODS: To test the algorithms, both in silico and phantom experiments were performed. The phantom experiments were performed on a Trilogy Varian linac and a HexaMotion programmable motion platform. High and low modulation VMAT plans for lung and prostate cancer cases were used along with eight patient-measured organ-specific trajectories. For both MLC leaf-fitting algorithms, the plans were run with their corresponding patient trajectories. To compare algorithms, the average exposure errors, i.e., the difference in shape between ideal and fitted MLC leaves by the algorithm, plan complexity and system latency of each experiment were calculated. RESULTS: Comparison of exposure errors for the in silico and phantom experiments showed minor differences between the two algorithms. The average exposure errors for in silico experiments with low/high plan complexity were 0.66/0.88 cm2 for direct optimization and 0.66/0.88 cm2 for piecewise optimization, respectively. The average exposure errors for the phantom experiments with low/high plan complexity were 0.73/1.02 cm2 for direct and 0.73/1.02 cm2 for piecewise optimization, respectively. The measured latency for the direct optimization was 226 ± 10 ms and for the piecewise algorithm was 228 ± 10 ms. In silico and phantom exposure errors quantified for each treatment plan demonstrated that the exposure errors from the high plan complexity (0.96 cm2 mean, 2.88 cm2 95% percentile) were all significantly different from the low plan complexity (0.70 cm2 mean, 2.18 cm2 95% percentile) (P < 0.001, two-tailed, Mann-Whitney statistical test). CONCLUSIONS: The comparison between the two leaf-fitting algorithms demonstrated no significant differences in exposure errors, neither in silico nor with phantom experiments. This study revealed that plan complexity impacts the overall exposure errors significantly more than the difference between the algorithms

Satisfaction With Psychology Training In the Veterans Healthcare Administration

Given that VA is the largest trainer of psychologists in the United States, this study sought to understand satisfaction with VA psychology training and which elements of training best predict trainees\u27 positive perceptions of training (e.g., willingness to choose training experience again, stated intentions to work in VA). Psychology trainees completed the Learners\u27 Perceptions Survey (LPS) from 2005 to 2017 (N = 5,342). Satisfaction was uniformly high. Trainee satisfaction was significantly associated with level of training, facility complexity, and some patient-mix factors. Learning environment (autonomy, time with patients, etc.), clinical faculty/preceptors (teaching ability, accessibility, etc.), and personal experiences (work/life balance, personal responsibility for patient care, etc.) were the biggest drivers of stated willingness to repeat training experiences in VA and seek employment there. Results have implications for psychologists involved in the provision of a training experience valued by trainees

Dzyaloshinsky-Moriya Spin Canting in the LTT Phase of La2-x-yEuySrxCuO4

The Cu spin magnetism in La2-x-yEuySrxCuO4 (x<=0.17; y<=0.2) has been studied by means of magnetization measurements up to 14 T. Our results clearly show that in the antiferromagnetic phase Dzyaloshinsky-Moriya (DM)superexchange causes Cu spin canting not only in the LTO phase but also in the LTLO and LTT phases. In La1.8Eu0.2CuO4 the canted DM-moment is about 50% larger than in pure La2CuO4 which we attribute to the larger octahedral tilt angle. We also find clear evidence that the size of the DM-moment does not change significantly at the structural transition at T_LT from LTO to LTLO and LTT. The most important change induced by the transition is a significant reduction of the magnetic coupling between the CuO2 planes. As a consequence, the spin-flip transition of the canted Cu spins which is observed in the LTO phase for magnetic field perpendicular to the CuO2 planes disappears in the LTT phase. The shape of the magnetization curves changes from the well known spin-flip type to a weak-ferromagnet type. However, no spontaneous weak ferromagnetism is observed even at very low temperatures, which seems to indicate that the interlayer decoupling in our samples is not perfect. Nonetheless, a small fraction (<15%) of the DM-moments can be remanently magnetized throughout the entire antiferromagnetically ordered LTT/LTLO phase, i.e. for T<T_LT and x<0.02. It appears that the remanent DM-moment is perpendicular to the CuO2 planes. For magnetic field parallel to the CuO2 planes we find that the critical field of the spin-flop transition decreases in the LTLO phase, which might indicate a competition between different in-plane anisotropies. To study the Cu spin magnetism in La2-x-yEuySrxCuO4, a careful analysis of the Van Vleck paramagnetism of the Eu3+ ions was performed.Comment: 22 pages, 27 figure

Vitrificación ovocitaria para posponer fecundidad: experiencia de la Unidad de Medicina Reproductiva de Clínica Monteblanco

Antecedentes: Múltiples variables médicas y sociales han llevado al desarrollo de técnicas que permitan a la mujer posponer su fertilidad; dentro de ellas la vitrificación ovocitaria surge como una técnica relativamente sencilla y muy promisoria en este campo. Objetivo: Presentar la experiencia del Centro de Medicina Reproductiva de Clínica Monteblanco, en mujeres que han vitrificado sus ovocitos y posteriormente han intentado embarazarse con ellos. Método: Se revisaron todos los casos de vitrificación ovocitaria con posterior intento de embarazo, realizados desde el año 2007 a la fecha. Resultados: Del total de ciclos de vitrificación ovoci-taria, 22 mujeres han intentado un embarazo posterior al procedimiento. La mediana de edad al momento de la vitrificación fue de 36 años. En 10 pacientes no hubo transferencia embrionaria, ya fuera por no fecundación (4 casos) o por detención del desarrollo embrionario (6 casos); 12 pacientes fueron transferidas, la mitad de ellas lograron embarazo. Discusión: En este trabajo se presenta la primera serie nacional de casos de vitrificación de óvulos con posterior intento de embarazo; 12 de 20 pacientes lograron ser transferidas y 6 de ellas lograron el embarazo. Las mujeres más jóvenes vitrificaron un mayor número de ovocitos, tuvieron más embriones y tuvieron una mayor posibilidad de lograr embarazo. Conclusión: Pese a que la vitrificación ovocitaria no es una solución definitiva a la postergación de la fertilidad, representa en estos casos una alternativa válida

Conservative kidney management and kidney supportive care:core components of integrated care for people with kidney failure

Integrated kidney care requires synergistic linkage between preventative care for people at risk for chronic kidney disease and health services providing care for people with kidney disease, ensuring holistic and coordinated care as people transition between acute and chronic kidney disease and the 3 modalities of kidney failure management: conservative kidney management, transplantation, and dialysis. People with kidney failure have many supportive care needs throughout their illness, regardless of treatment modality. Kidney supportive care is therefore a vital part of this integrated framework, but is nonexistent, poorly developed, and/or poorly integrated with kidney care in many settings, especially in low- and middle-income countries. To address this, the International Society of Nephrology has (i) coordinated the development of consensus definitions of conservative kidney management and kidney supportive care to promote international understanding and awareness of these active treatments; and (ii) identified key considerations for the development and expansion of conservative kidney management and kidney supportive care programs, especially in low resource settings, where access to kidney replacement therapy is restricted or not available. This article presents the definitions for conservative kidney management and kidney supportive care; describes their core components with some illustrative examples to highlight key points; and describes some of the additional considerations for delivering conservative kidney management and kidney supportive care in low resource settings.</p

Development of the Tilburg Pregnancy Distress Scale: the TPDS

Contains fulltext : 96807.pdf (publisher's version ) (Open Access)ABSTRACT: BACKGROUND: Pregnant women with high levels of stress, depression and/or anxiety are at increased risk for adverse perinatal outcomes and impaired neurologic and emotional development of the offspring. Pregnancy specific instruments to measure psychological functioning during gestation are scarce and do not define items based on in-depth interviews of pregnant and recently delivered women. The current study developed a pregnancy specific scale that measures psychological functioning using in-depth interviews. METHODS: Three focus groups were formed to discuss issues most relevant to pregnancy distress; 22 candidate items were derived for pilot testing (study I, n = 419) its psychometric properties by means of explorative factor analyses (EFA). This resulted in a 17-item TPDS which was further explored by confirmatory factor analyses (CFA) and concurrent and construct validity assessment (study II, n = 454). RESULTS: EFA in study I suggested a two component solution (negative affect (NA) and partner involvement (PI)). CFA in study II resulted in a higher order model of the NA subscale into three more subscales: NA regarding confinement, delivery and general health. TPDS, EPDS and GAD-7 were all significantly correlated. CONCLUSIONS: The TPDS constitutes a valid and user friendly instrument to assess pregnancy distress. In addition to its proven ability to pick up pregnancy specific negative affect it also includes an important sub-scale measuring perceived partner involvement

Evaluation of dog owners' perceptions concerning radiation therapy

<p>Abstract</p> <p>Background</p> <p>External radiation therapy (RT) has been available for small animals in Sweden since 2006. This study was designed to obtain information on owner experiences and perceptions related to RT of cancer in their dogs. Another survey was used to determine the attitudes about use of RT in a group of Swedish veterinarians. Their responses were analyzed and compared to their level of knowledge of oncology and RT.</p> <p>Methods</p> <p>Owners of all dogs (n = 23) who had undergone RT for malignancy at Jönköping Small Animal Hospital between March 2006 to September 2007 were interviewed. A questionnaire was given to a selected group of veterinarians.</p> <p>Results</p> <p>All 23 owners responded. All owners thought that their dog did well during RT and most that their dog was also fine during the following phase when acute RT-related skin reactions occur and heal. Three owners stated that their dog had pain that negatively impacted quality of life because of radiation dermatitis. Five owners reported that RT positively impacted quality of life of the dog during the first weeks after RT because palliation was achieved. The owners were not disturbed by the efforts required of them. All but one owner (22 of 23) stated that they would make the same decision about RT again if a similar situation occurred. The most important factor for this decision was the chance to delay occurrence of tumour-related discomfort. The chance for cure was of less importance but still essential, followed by expected side effects. Time commitments, travel, number of treatments required and financial cost; all had low impact. The veterinarian survey showed that less background knowledge of small animal oncology/RT was associated with more negative expectations of RT for small animals.</p> <p>Conclusion</p> <p>The results show that for these owners, RT was a worthwhile treatment modality and that the discomfort for the dog was manageable and acceptable relative to the benefits. Improved continuing education about small animal RT in Sweden will likely result in increased evidence-based and positive treatment recommendations concerning RT by veterinarians.</p

Homing endonuclease I-TevIII: dimerization as a means to a double-strand break

Homing endonucleases are unusual enzymes, capable of recognizing lengthy DNA sequences and cleaving site-specifically within genomes. Many homing endonucleases are encoded within group I introns, and such enzymes promote the mobility reactions of these introns. Phage T4 has three group I introns, within the td, nrdB and nrdD genes. The td and nrdD introns are mobile, whereas the nrdB intron is not. Phage RB3 is a close relative of T4 and has a lengthier nrdB intron. Here, we describe I-TevIII, the H–N–H endonuclease encoded by the RB3 nrdB intron. In contrast to previous reports, we demonstrate that this intron is mobile, and that this mobility is dependent on I-TevIII, which generates 2-nt 3′ extensions. The enzyme has a distinct catalytic domain, which contains the H–N–H motif, and DNA-binding domain, which contains two zinc fingers required for interaction with the DNA substrate. Most importantly, I-TevIII, unlike the H–N–H endonucleases described so far, makes a double-strand break on the DNA homing site by acting as a dimer. Through deletion analysis, the dimerization interface was mapped to the DNA-binding domain. The unusual propensity of I-TevIII to dimerize to achieve cleavage of both DNA strands underscores the versatility of the H–N–H enzyme family

Analgesics use and ESRD in younger age: a case-control study

<p>Abstract</p> <p>Background</p> <p>An ad hoc peer-review committee was jointly appointed by Drug Authorities and Industry in Germany, Austria and Switzerland in 1999/2000 to review the evidence for a causal relation between phenacetin-free analgesics and nephropathy. The committee found the evidence as inconclusive and requested a new case-control study of adequate design.</p> <p>Methods</p> <p>We performed a population-based case-control study with incident cases of end-stage renal disease (ESRD) under the age of 50 years and four age and sex-matched neighborhood controls in 170 dialysis centers (153 in Germany, and 17 in Austria) from January 1, 2001 to December 31, 2004. Data on lifetime medical history, risk factors, treatment, job exposure and intake of analgesics were obtained in a standardized face-to-face interview using memory aids to enhance accuracy. Study design, study performance, analysis plan, and study report were approved by an independent international advisory committee and by the Drug Authorities involved. Unconditional logistic regression analyses were performed.</p> <p>Results</p> <p>The analysis included 907 cases and 3,622 controls who had never used phenacetin-containing analgesics in their lifetime. The use of high cumulative lifetime dose (3^rdtertile) of analgesics in the period up to five years before dialysis was not associated with later ESRD. Adjusted odds ratios with 95% confidence intervals were 0.8 (0.7 – 1.0) and 1.0 (0.8 – 1.3) for ever- compared with no or low use and high use compared with low use, respectively. The same results were found for all analgesics and for mono-, and combination preparations with and without caffeine. No increased risk was shown in analyses stratifying for dose and duration. Dose-response analyses showed that analgesic use was not associated with an increased risk for ESRD up to 3.5 kg cumulative lifetime dose (98 % of the cases with ESRD). While the large subgroup of users with a lifetime dose up to 0.5 kg (278 cases and 1365 controls) showed a significantly decreased risk, a tiny subgroup of extreme users with over 3.5 kg lifetime use (19 cases and 11 controls) showed a significant risk increase. The detailed evaluation of 22 cases and 19 controls with over 2.5 kg lifetime use recommended by the regulatory advisors showed an impressive excess of other conditions than analgesics triggering the evolution of ESRD in cases compared with controls.</p> <p>Conclusion</p> <p>We found no clinically meaningful evidence for an increased risk of ESRD associated with use of phenacetin-free analgesics in single or combined formulation. The apparent risk increase shown in a small subgroup with extreme lifetime dose of analgesics is most likely an indirect, non-causal association. This hypothesis, however, cannot be confirmed or refuted within our case-control study. Overall, our results lend support to the mounting evidence that phenacetin-free analgesics do not induce ESRD and that the notion of "analgesic nephropathy" needs to be re-evaluated.</p