Evaluación de la causalidad en estudios observacionales: Aplicación en una cohorte de enfermos críticos y en una cohorte de pacientes con trombosis venosa profunda

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Medicina Preventiva y Salud Pública y Microbiología. Fecha de lectura: 26-02-201

Diseño de agrupaciones de antenas alimentadas con redes corporativas en tecnología de guía de onda

Tradicionalmente en el grupo de investigación RFCAS se han diseñado redes de alimentación de diversa índole, como son por ejemplo redes tipo serie o paralelo en tecnología microstrip o SIW. Sin embargo, para el caso de redes en tecnología de guía de onda la distribución tipo serie ha sido la más utilizada debido al ahorro de espacio que conlleva frente a la de tipo paralelo. De hecho, agrupaciones en paralelo distribuidas sobre el plano E ni siquiera han sido estudiadas. En el presente documento se ha procedido a analizar el comportamiento de distintas agrupaciones de antenas alimentadas por redes corporativas en tecnología de guía de onda. Se ha partido de la hipótesis de que el elemento unitario de las agrupaciones a estudiar se iba a comportar de manera adecuada cuando fuera replicado a lo largo de las diferentes estructuras que se han propuesto. De este modo se han podido extraer las conclusiones pertinentes sobre el comportamiento de las distintas redes diseñadas, independientemente del tipo de array que ha sido alimentado con ellas. Como elemento radiante se ha tomado uno perteneciente al grupo de investigación RFCAS ya diseñado y medido, el cual consiste en un parche circular microstrip apilado sobre una ranura rectangular microstrip para polarización lineal, que es alimentado a través de una guía de onda rectangular estándar WR-51. El diseño ha sido optimizado para la porción superior de la banda Ku del espectro radioeléctrico, de 16 a 18 GHz. Las estructuras en guía que se han propuesto han sido dos arrays lineales de 4 elementos, uno de ellos en plano H y el otro en plano E. Por lo tanto, gran parte del trabajo que se ha realizado ha tratado sobre el modelado de los distintos elementos de que se componen las redes de alimentación corporativas que alimentan dichos arrays, tales como uniones en T, en Y o codos en ambos planos. Todos los diseños planteados han sido construidos y medidos como paso posterior a la etapa de diseño. Finalmente, se ha diseñado una transición de guía de onda a conector coaxial para el caso del plano H, debido a la imposibilidad de cargar todos los puertos de la red a su impedancia característica para medirla en transmisión. Dicha transición ha sido replicada por 4 en una única pieza, lo que ha permitido caracterizar el array de elementos radiantes y la red de alimentación corporativa por separado. Con todo esto se ha realizado un estudio muy completo de los elementos de que se compone la antena plano H, y se ha verificado si el parámetro de adaptación de la citada antena se corresponde con el de la red de alimentación y el array de parches sobre ranuras medidos por separado.Several kind of feeding networks had been conventionally designed in RFCAS research group, such as serial or parallel network based on microstrip or substrate integrated waveguide (SIW) technology. Nevertheless, waveguide technology had been mainly used in serial feeding structures design owing to their space-saving properties in comparison to parallel example. As a matter of fact, E-plane parallel arrays had been never studied at RFCAS. In the present document different array antenna configurations fed by corporate waveguide feeding networks are analyzed. As a starting point, it is assumed that the single element of all array antennas would behave appropriately when it is replicated along the different proposed structures. This way, conclusions about all designed networks had been drawn regardless of which array antenna type was being fed. The selected radiating element belongs to RFCAS and it is already designed and measured. It consists of a circular microstrip patch stacked to a microstrip slot fed by a standard WR-51 waveguide for linear polarization. Designed antenna is optimized for upper Ku band part, from 16 to 18 GHz. Proposed waveguide structures are two 4-element linear arrays, one at H-plane and E-plane respectively. Therefore, outlining both E-plane and H-plane elements such as Tjunctions, Y-junctions and bends became the major part of the developed work. All the presented designs have been manufactured and measured. Finally, a coaxial to waveguide transition has been designed for H-plane antenna due to output load matching is not physically possible. This transition is repeated 4 times in a single piece, so both array of radiating elements and corporate waveguide feeding network are accessible to be measured separately. All this leads to an exhaustive characterization of the elements which form part of the complete H-plane array antenna. Adaptation coefficient is measured from complete antenna input port. It is also estimated by joining both array of radiating elements and corporate waveguide feeding network Sparameters so this measures can be validated

Gain-Reconfigurable Hybrid Metal-Graphene Printed Yagi Antenna for Energy Harvesting Applications

This paper presents a hybrid metal-graphene printed Yagi antenna with reconfigurable gain that operates in the 5.5-GHz band. The balun and the driven elements are made of copper, while the directors are made of graphene. The graphene acts as a tunable material in the design. By switching the conductivity of the graphene, it is achieved a similar effect to adding or subtracting directors in the antenna. Hence the gain of the printed Yagi can be easily controlled. This could be of special interest in RF energy harvesting in the design of reconfigurable harvesting elements.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

CHARMS and PROBAST at your fingertips:a template for data extraction and risk of bias assessment in systematic reviews of predictive models

Background: Systematic reviews of studies of clinical prediction models are becoming increasingly abundant in the literature. Data extraction and risk of bias assessment are critical steps in any systematic review. CHARMS and PROBAST are the standard tools used for these steps in these reviews of clinical prediction models. Results: We developed an Excel template for data extraction and risk of bias assessment of clinical prediction models including both recommended tools. The template makes it easier for reviewers to extract data, to assess the risk of bias and applicability, and to produce results tables and figures ready for publication. Conclusion: We hope this template will simplify and standardize the process of conducting a systematic review of prediction models, and promote a better and more comprehensive reporting of these systematic reviews

Hospital volume and outcomes for acute pulmonary embolism: Multinational population based cohort study

[Objectives] To evaluate the association between experience in the management of acute pulmonary embolism, reflected by hospital case volume, and mortality.[Design] Multinational population based cohort study using data from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) registry between 1 January 2001 and 31 August 2018.[Setting] 353 hospitals in 16 countries.[Participants] 39 257 consecutive patients with confirmed diagnosis of acute symptomatic pulmonary embolism.[Main] outcome measure Pulmonary embolism related mortality within 30 days after diagnosis of the condition.[Results] Patients with acute symptomatic pulmonary embolism admitted to high volume hospitals (>40 pulmonary embolisms per year) had a higher burden of comorbidities. A significant inverse association was seen between annual hospital volume and pulmonary embolism related mortality. Admission to hospitals in the highest quarter (that is, >40 pulmonary embolisms per year) was associated with a 44% reduction in the adjusted odds of pulmonary embolism related mortality at 30 days compared with admission to hospitals in the lowest quarter (<15 pulmonary embolisms per year; adjusted risk 1.3% v 2.3%; adjusted odds ratio 0.56 (95% confidence interval 0.33 to 0.95); P=0.03). Results were consistent in all sensitivity analyses. All cause mortality at 30 days was not significantly reduced between the two quarters (adjusted odds ratio 0.78 (0.50 to 1.22); P=0.28). Survivors showed little change in the odds of recurrent venous thromboembolism (odds ratio 0.76 (0.49 to 1.19)) or major bleeding (1.07 (0.77 to 1.47)) between the low and high volume hospitals.[Conclusions] In patients with acute symptomatic pulmonary embolism, admission to high volume hospitals was associated with significant reductions in adjusted pulmonary embolism related mortality at 30 days. These findings could have implications for management strategies.Peer reviewe

The prevalence of intraarticular associated lesions after acute acromioclavicular joint injuries is 20%. A systematic review and meta-analysis.

Purpose To synthesise the evidence on the prevalence of associated intraarticular lesions in subjects with acute acromioclavicular joint (ACJ) dislocations. Methods A search in two electronic databases (PUMBMED and EMBASE) was performed from 1985 to 2019. Two independent reviewers selected studies that complied with the following inclusion criteria: (1) the study included data on surgically treated ACJ dislocation grade III–V in the Rockwood classification, (2) the ACJ injuries were acute (the surgery was performed less than 6 weeks after injury), (3) an arthroscopic evaluation of the glenohumeral joint was performed during surgery. The quality of the studies included was assessed using the tool of the Joanna Briggs Institute. Results A total of 47 studies with acute ACJ injuries met the initial inclusion criteria. Of these, 21 studies (9 retrospective case series, 9 prospective case series and 3 retrospective cohort studies) presented data on associated intraarticular lesions amenable for use in the meta-analysis. The meta-analysed studies included a total of 860 subjects with acute ACJ dislocations with a male/female ratio of 6.5 and a mean age of 32 years. The meta-analysis showed a prevalence of associated intraarticular lesions in subjects with acute ACJ of 19.9% (95% confidence interval [CI] 14.0–26.4%; 21 studies, 860 analysed participants; P = 0.000; I2: 74.5% random-effects model; low risk of bias). Conclusion One in five subjects with surgically treated acute ACJ dislocations will have an associated intraarticular lesion that requires further intervention. The case for a customary arthroscopic evaluation of the joint, even when an open procedure is performed to deal with the ACJ dislocation, is strong.pre-print798 K

Responsiveness of the Spanish Version of Newcastle Stroke-Specific Quality of Life (NEWSQOL)

A prospective observational study was conducted to assess the responsiveness of the Spanish version of NEWSQOL. The sample contained 128 patients who filled in the question-naires before and after a physical therapy intervention. The responsiveness was assessed with p-values using the effect size (ES) and the standardized response means (SRMs) of the change. Besides, two other external criteria were used to distinguish patients who improved with the treatment from those who remained stable. This classification was based on one functional independence measure (the Barthel Index) and one disability measure (the modified Rankin Scale). Results: There was a statistically significant correlation (Spearman?s coefficient = p < 0.01) between the domains of the Spanish version of NEWSQOL in relation to the Barthel Index and the modified Rankin Scale. All domains showed between marked-to-mild change responsiveness except sleep and relationships; mobility (ES 0.66 and SRM 0.92) and activities of daily living (ES 0.75 and SRM 0.87) were markedly responsive; communication (ES 0.38 and SRM 0.61) was moderately responsive; and pain, vision, cognition, feelings, emotions and fatigue were mildly responsive (ES 0.21-0.41 and SRM 0.23-0.44). Conclusion: The Spanish version of NEWSQOL shows between marked and mild responsiveness to measure the perception of QoL in post-stroke patients. Therefore, its use can be suitable for eval-uation studies, clinical trials and clinical practice

Evaluation of a Planar Reconfigurable Phased Array Antenna Driven by a Multi-Channel Beamforming Module at Ka Band

© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksIn this paper, a planar active phased array antenna demonstration with linear polarization (LP) at Ka Band (28-30 GHz) is presented. The proof of concept is carried out to evaluate the possible problems that may arise, to analyze possible calibration stages and to assess the viability of the integration of an active system with a Multi-Channel Beamforming Module (MCBM). To fulfill this task an 8times 8-element planar array arranged in column subarrays of 1times 8 elements for 1D beam steering is proposed. The single element consists of a printed circular patch connected to a microstrip feeding line through metallic vias in a multilayered structure. Both the amplitude and phase distributions are performed by a commercial integrated circuit (IC) designed for transmission purposes, from the common port to each of the 8 output ports. Thus, an evaluation of the IC performance is also included within this work. Despite the inherent amplitude and phase feeding errors of the IC, the beam-steering accuracy of the system is reasonable. A nice correspondence between the simulated and measured 8times 8-element array beam steering directions is obtained, with errors below 1° in the steering of the beamThis work was supported in part by the Spanish Government, Ministry of Economy, National Program of Research, Development and Innovation through the Project FUTURE RADIO ’’Radio systems and technologies for high capacity terrestrial and satellite communications in an hyperconnected world’’ under Grant TEC2017-85529-C3-1-R, and in part by the Project JETSTREAM ’’Desarrollo de una antena banda KA embarcada para la prestación de servicios de acceso a Internet por satélite en aviación comercial’’ in collaboration with TELNET Redes Inteligentes S.A. under Grant RTC-2015-3495-

Similar CD4/CD8 Ratio Recovery After Initiation of Dolutegravir Plus Lamivudine Versus Dolutegravir or Bictegravir-Based Three-Drug Regimens in Naive Adults With HIV

The initiation of antiretroviral treatment based on a 2-drug regimen (2DR) with dolutegravir plus lamivudine has demonstrated non-inferior efficacy than dolutegravir-based three-drug regimens (3DR). We aimed to assess whether the treatment initiation with this 2DR has a different impact on the CD4/CD8 ratio recovery than INSTI-based 3DR. Methods: We emulated a target trial using observational data from the Spanish HIV Research Network cohort (CoRIS). The outcomes of interest were the normalization of the CD4/CD8 ratio at 48 weeks using three different cutoffs: 0.5, 1.0, and 1.5. We matched each participant who started 2DR with up to four participants who received 3DR. Subsequently, we fitted generalized estimating equation (GEE) models and used the Kaplan–Meier method for survival curves. Results: We included 485, 805, and 924 participants for cutoffs of 0.5, 1.0, and 1.5, respectively. At 48 weeks, 45% of participants achieved a CD4/CD8 ratio >0.5, 15% achieved a ratio >1.0, and 6% achieved a ratio >1.5. GEE models yielded a similar risk of reaching a CD4/CD8 ratio >0.5 (OR 1.00, 95% CI 0.67 - 1.50), CD4/CD8 >1.0 (OR 1.03, 95% CI 0.68 - 1.58), and CD4/CD8 >1.5 (OR 0.86, 95% CI 0.48 - 1.54) between both treatment strategies. There were no differences between 2DR and 3DR in the incidence ratio of CD4/CD8 ratio normalization at 0.5, 1.0 and 1.5 cut-offs. Conclusions: In this large cohort study in people with HIV, ART initiation with dolutegravir plus lamivudine vs. dolutegravir or bictegravir-based triple antiretroviral therapy showed no difference in the rates of CD4/CD8 normalization at 48 weeks