146,397 research outputs found
Efficacy of dienogest in improving pain in women with endometriosis : a 12-month single-center experience
No full textPurpose: Dienogest has recently been marketed as a medical treatment for endometriosis. Given the recent introduction on the market of Dienogest, little data are available regarding its effectiveness in routine clinical practice. Methods: The study is an observational, single-center, cohort study. Eligible was women with a surgical diagnosis of endometriosis dating back <24 months or a clinical/instrumental diagnosis of endometriosis and endometriosis-associated pelvic pain score of at least 40 mm on a 100-mm visual analog scale (VAS) at start of treatment and who had been taking Dienogest 2 mg once daily treatment at the time of study entry for no more than 30 days, consecutively observed between September 2013 to September 2014. In accordance with routine practice, women came back for clinical assessment and evaluation of pain after 1 (V1), 3 (V2), and 12 (V3) months. Results: A total of 132 women were enrolled in the study. A total of 21 of the enrolled patients were released from the study during follow-up due to adverse effects. The mean pelvic pain VAS score at baseline was 8.9 (SD 1.3). The corresponding values were 6.7 (SD 3.2) and 5.7 (SD 3.7) for dyspareunia and dyschezia. The mean VAS scores progressively and significantly decreased to 0.9 (SD 1.6) for pelvic pain, 1.4 (SD 2.1) for dyspareunia and 0.2 (SD 0.9) for dyschezia, respectively, 12 months after start of treatment. Conclusion: This study confirms that in routine clinical practice, Dienogest 2 mg is an effective and well-tolerated treatment for endometriosis-related pain in women with endometriosis
Evaluation of the proton range accuracy using Single and Dual Energy Computed Tomography
No full textProton therapy is a highly advanced form of external beam radiotherapy, which uses proton beams to treat cancers. Protons are particularly suited for radiotherapy because heavy particles, interacting with matter, deposit most of their energy at the end of their track. It allows for well-conformed dose distributions to the target area while minimizing exposure to surrounding healthy tissues and organs at risk. In addition, ongoing research reveals that protons have distinct biological, immunological, and clinical effects compared to photons, beyond just dose distribution differences.
X-ray CT images are currently the standard for proton beam planning, but they have limitations due to the need to convert electron density maps into stopping power ratios (SPR) maps. CT numbers (HU values) noise and the lack of a consistent conversion to SPR lead to imperfect dose calculations and introduce density uncertainties. Additionally, CT scans only capture a single snapshot of patient anatomy, while daily variations during treatment cause setup uncertainties. Treatment planning systems (TPSs) are designed for account density and setup uncertainties through robust optimization. Density and setup uncertainty values are not uniquely defined. They are institution-specific, depending on the utilized treatment modalities, the clinical experience and the target anatomic localization. Density uncertainty typically ranges within 3% and 3.5%, whereas, setup uncertainty varies from 1 mm up to 5mm.
Within the scientific community, there is a strong interest in reducing the density uncertainties. The advent of Dual-Energy CT (DECT) scanners has introduced new options to increase the SPR conversion accuracy compared to Single-Energy CT (SECT). The Siemens Syngo.via software is an available commercial solution to perform the DE raw image processing, generating Dual Energy Monoenergetic Plus images. In addition, the software includes a tool, DirectSPR, able to directly calculate voxel by voxel the proton SPR, without resorting to HU conversion.
This work aims to evaluate the impact of HU to SPR conversion methods on TPS proton
range estimation. HU to SPR conversion relationships were derived from CT calibrations. The following methods were implemented and evaluated: the SECT tissue-substitute method and, on the other hand, the SECT and Dual Energy Monoenergetic Plus Stoichiometric calibration methods. In different scenarios, the proton range was directly measured with a multi-layer ion chamber and compared with the one derived from TPS dose calculation on DirectSPR maps and SECT and DECT images.
Firstly, tissue-surrogate solid plugs were individually irradiated with a single pencil beam
of 226 MeV proton. DirectSPR-derived proton range showed a better agreement with measurements than CT calibration-based methods differing at most by 1% (SECT and 75KeV Monoenergetic Plus with the stoichiometric calibration respectively by 6.5% and 4.5%), for all the plugs except for high-density ones. All the TPS calculated proton ranges significantly differed (up to 32%) from the measurement for the He Cortical Bone plug. This result will require additional investigation. Plug results can not be fully translated to human tissues, since they have different chemical compositions. For this purpose, animal organ samples were used. They were irradiated with single pencil beams of different energies (100 MeV, 150 MeV and 226 MeV) and with a simple intensity modulated proton therapy (IMPT) plan (a dose cube). Three irradiation points were identified on each sample surface and the proton range was probed at each of them. Proton range differences between measures and TPS-derived ones had no dependency
on beam energy. However, the results of this investigation do not confirm the high accuracy in SPR assignment of DirectSPR than SECT and DECT calibration-based methods, indeed, proton range differences with measures were very close within the various approaches.
The density uncertainty was evaluated on the data derived from IMPT irradiation on animal organ samples, given the closeness to clinical treatment conditions. A value of 2% could be taken as density uncertainty associated with the use of SECT and Monoenergetic Plus75keV image with the relative stoichiometric calibration curve in proton dose calculation, while the value obtained for the DirectSPR was higher, 2.8%. The high standard deviations of the multiple irradiation point measurements suggest the presence of residual setup errors affecting the results and the necessity to improve setup repeatability for further investigations.
The results of this study confirm the feasibility of the use of DirectSPR and Monoenergetic
Plus images generated by the Syngo.via software as input to the Raystation TPS for
proton dose calculation. Although preliminary, the results of this study support the reduction of the 3.5% clinical density uncertainty enabled by the implementation of dual-energy CT as suggested by many authors
The Pre-Producers
No full textUntil its sales of a product materialize, a firm is a "pre-producer" in the market for that product. That firm may may be a new start-up, or it may already sell other products. Firms that do not succeed in generating sales eventually become discouraged and move on to other activities. When this fate befalls a lot of firms, as it recently did in several IT-related businesses, the industry experiences a "shakeout." In the model that I will present, during the shakeout some firms switch to flatter, safer earnings. This switch raises earnings at the time of the shakeout but lowers them in the long run, and it therefore raises earnings-price ratios. This has happened on the Nasdaq since March, 2000 when the Nasdaq shakeout began.
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
M. Ioan. Christoph Kiesevvetter, Ill. Gymnasii Wilhelmo-Ernestini Rector L B S D. Non alio magis pietatis adfectu universi ad obeunda munia obstringimur ...
No full textM. IOAN. CHRISTOPH KIESEVVETTER, ILL. GYMNASII WILHELMO-ERNESTINI RECTOR L B S D. NON ALIO MAGIS PIETATIS ADFECTU UNIVERSI AD OBEUNDA MUNIA OBSTRINGIMUR ...
M. Ioan. Christoph Kiesevvetter, Ill. Gymnasii Wilhelmo-Ernestini Rector L B S D. Non alio magis pietatis adfectu universi ad obeunda munia obstringimur ... ([1]gef)
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Fifteen years follow-up of photorefractive keratectomy up to 10 D of myopia: outcomes and analysis of the refractive regression
No full textPURPOSE:
To evaluate outcomes of photorefractive keratectomy up to -10.00 D of myopia and -4.50 of astigmatism and to develop a predictive model for the refractive changes in the long term.
SETTING:
Vissum Corporation and Miguel Hernandez University (Alicante, Spain).
DESIGN:
Retrospective-prospective observational series of cases.
METHODS:
This study included 33 eyes of 33 patients aged 46.79±7.04 years (range 40-57) operated with the VISX 20/20 excimer laser with optical zones of 6 mm. No mitomycin C was used in any of these cases. The minimum follow-up was 15 years. The main outcome measures were: uncorrected and corrected distance visual acuity, manifest refraction and corneal topography. Linear regression models were developed from the observed refractive changes over time.
RESULTS:
Safety and efficacy indexes at 15 years were 1.18 and 0.83, respectively. No statistically significant differences were detected for any keratometric variable during the follow-up (p≥0.103). 15 years after the surgery 54.55% of the eyes were within ±1.00 D of spherical equivalent and 84.85% within ±2.00 D. The uncorrected distance visual acuity at 15 years was 20/25 or better in 60.6% of the eyes and 20/40 or better in 72.73% of the eyes. The correlation between the attempted and the achieved refractions was r=0.948 (p<0.001) at 1 year, and r=0.821 (p<0.001) at 15 years. No corneal ectasia was detected in any case during the follow-up.
CONCLUSIONS:
Photorefractive keratectomy is a safe refractive procedure in the long term within the range of myopia currently considered suitable for its use, although its efficacy decreases with time, especially, in high myopia. The model developed predicts a myopic regression of 2.00 D at 15 years for an ablation depth of 130 μm
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Deficiencia de 25-hidoroxivitamina D, VDBP y péptidos antimicrobianos vitamina D dependientes en el paciente séptico
No full textIntroducción: La vitamina D desempeña un papel importante en la regulación de la inflamación y protección frente a las infecciones, induciendo la síntesis de péptidos antimicrobianos. La deficiencia de vitamina D se ha asociado con un incremento de mortalidad en pacientes sépticos adultos. La proteína transportadora de vitamina D (VDBP) también tiene funciones antiinflamatorias y autoinmunes. Objetivo: Evaluar los niveles de 25-hidroxivitamina D (25(OH) D), 1,25-dihidroxi vitamina D (1,25(OH)2 D), VDBP, catelicidina y β-2-defensina en pacientes adultos con sepsis/shock séptico y relacionarlos con parámetros inflamatorios (leucocitos, proteína C reactiva y procalcitonina) y pronóstico/mortalidad. Material y Métodos: Estudio prospectivo observacional realizado en una Unidad de Cuidados Intensivos (UCI). Los niveles séricos de 25(OH) D, 1,25(OH)2 D, VDBP, catelicidina y β-2-defensina fueron medidos al ingreso en UCI. Resultados: De un total de 75 pacientes consecutivos sépticos, 62 (82,8%) tenían niveles deficientes de vitamina D (<20 ng/mL). Los niveles de 25(OH) D eran significativamente menores en primavera comparados con los obtenidos en otoño (p<0.001). En el estudio de correlación con parámetros inflamatorios, sólo se correlaciona la VDBP con los leucocitos (r=0,260, p=0.026). Se observan diferencias estadísticamente significativas entre supervivientes y no supervivientes en los niveles de VDBP (OR 8,74, IC 95%=1,18-65,01, p=0,034). Conclusiones: La prevalencia de deficiencia de vitamina D es elevada y el estatus de vitamina D exhibe una fuerte variación estacional en pacientes sépticos. La VDBP es la única variable que se asocia de manera significativa con el riesgo de mortalidad, así niveles altos de VDBP parecen ser protectores.Máster en Condicionantes Genéticos, Nutricionales y Ambientales del Crecimiento y el Desarroll
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