3,944 research outputs found

    A Kidney Biopsy Simulation Training Program: First Year\u27s Results

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    BACKGROUND: Nephrology attracts fewer medical graduates despite the growing care and workforce demand. Interventional Nephrology could re-foster interest in this subspecialty. Percutaneous kidney biopsy (PKB) is the most common procedure and should be adequately taught through simulation training according to ACGME requirements. We initiated a PKB simulation training program and we designed a two-year study in order to examine its effect on the confidence level, the procedural competence and the satisfaction with this training of Nephrology fellows compared to historical controls (fellows trained on PKBs before the initiation of the program). METHODS: All fellows were consented and trained at UNM’s simulation center (BATCAVE) with a renal biopsy ultrasound training model (CAE Healthcare Blue PhantomTM). Participants demographics and previous PKB experience was collected. Pre-assigned readings, online videos and hands-on practice on the simulation model were utilized as educational strategies. Performance of the trainee during each one-hour session was graded by the use of an evaluation form specifically designed for PKBs. Pre-and post-simulation surveys evaluated the participants’ confidence level quantitatively. All participants completed the satisfaction with PKB simulation experience scale (PKB-SSE). RESULTS: All three 1st and 2nd year current renal fellows completed the simulation training. The following table summarizes the basic information acquired from their training. Overall, the program enhanced the confidence level of fellows without previous experience on performing PKBs. All fellows expressed a high level of satisfaction from their participation in this training. CONCLUSIONS: PKB simulation training may improve trainees’ confidence level especially for those without prior experience as well as their satisfaction with the training. The procedural competence of the trainees on PKBs will be evaluated during the second year of their fellowship and will be compared to the procedural competence of historical controls

    Progress with the Upgrade of the SPS for the HL-LHC Era

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    The demanding beam performance requirements of the High Luminosity (HL-) LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.Comment: 3 p. Presented at 4th International Particle Accelerator Conference (IPAC 2013

    Dependence of e-cloud on the longitudinal bunch profile: studies in the PS & extension to the HL-LHC

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    Recent studies have shown that the prospects for significantly increasing bunch intensities in the LHC for the luminosity upgrade (HL-LHC) may be severely limited by the available cryogenic cooling capacity and the electron-cloud (EC) driven beam instability. However, it is planned that during the HL-LHC era the bunch intensities in the LHC will go up by nearly a factor of two compared to the LHC-design values. This motivates the exploration of additional EC mitigation techniques that can be adopted in addition to those already in place. Preliminary simulations indicated that long flat bunches can be beneficial over Gaussian bunches to reduce the EC build up. Rigorous studies using realistic bunch profiles have never been done. Therefore, we have undertaken an in-depth investigation in the CERN 26 GeV PS to see if we can validate the previous findings and, in particular, if flattening the bunch can mitigate the EC. Here we present the results from dedicated EC measurements in the PS using a variety of bunch shapes and a comparison with simulations. Finally, we investigate if reshaping the bunch profiles using a 2nd harmonic rf cavity can mitigate EC in the HL-LHC

    Measurements of the LHC longitudinal resistive impedance with beam

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    The resistive part of the longitudinal impedance contributes to the heat deposition on different elements in the LHC ring including the beam screens, where it has to be absorbed by the cryogenic system and can be a practical limitation for the maximum beam intensity. In this paper, we present the first measurements of the LHC longitudinal resistive impedance with beam, done through synchronous phase shift measurements duringMachine Development sessions in 2012. Synchronous phase shift is measured for different bunch intensities and lengths using the high-precision LHC Beam Phase Module and then data are post-processed to further increase the accuracy. The dependence of the energy loss per particle on bunch length is then obtained and compared with the expected values found using the LHC impedance model

    Unraveling the formation dynamics of metallic femtosecond laser induced periodic surface structures

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    Femtosecond laser surface processing (FLSP) is an emerging fabrication technique to efficiently control the surface morphology of many types of materials including metals. However, the theoretical understanding of the FLSP formation dynamics is not a trivial task, since it involves the interaction of various physical processes (electromagnetic, thermal, fluid dynamics) and remains relatively unexplored. In this work, we tackle this problem and present rigorous theoretical results relevant to low-fluence FLSP that accurately match the outcomes of an experimental campaign focused on the formation dynamics of laser induced periodic surface structures (LIPSS) on stainless steel. More specifically, the topology and maximum depth of LIPSS trenches are theoretically and experimentally investigated as a function of the number of laser pulses. Moreover, precise LIPSS morphology measurements are performed using atomic force microscopy (AFM). The proposed comprehensive simulation study is based on two-temperature model (TTM) non-equilibrium thermal simulations coupled with fluid dynamic computations to capture the melting metal phase occurring during FLSP. Our rigorous simulation results are found to be in excellent agreement with the AFM measurements. The presented theoretical framework to model FLSP under low-fluence femtosecond laser pulses will be beneficial to various emerging applications of LIPSS on metallic surfaces, such as cooling high-powered laser diodes and controlling the thermal emission or absorption of metals

    Physicians’ Considerations and Practice Recommendations Regarding the Use of Sodium-Glucose Cotransporter-2 Inhibitors

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    Sodium-glucose cotransporter-2 inhibitors (SGLT-2is) (canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin), although initially developed as glucose-lowering drugs, provide significant beneficial effects on cardiorenal outcomes, including heart failure, regardless of type 2 diabetes status. Integration of SGLT-2is into clinical practice requires practical guidance for physicians about their use. To overcome physicians’ clinical inertia for SGLT-2i use, including addressing safety, potentially a barrier to their use, a roundtable discussion with physicians from three specialties (cardiology, endocrinology, and nephrology) was conducted. This review summarizes the physicians’ clinical experience and recommendations about SGLT-2i use across different patient populations, taking into consideration the beneficial effects of SGLT-2is and their safety. The key aspects discussed regarding SGLT-2i safety include acute effects on kidney function (estimated glomerular filtration rate acute dip upon SGLT-2i initiation and acute kidney injury), volume depletion, diabetic ketoacidosis, genitourinary infections, hyperkalemia, and hypoglycemia. To mitigate any potential risks related to SGLT-2i safety, physicians can make minor adjustments to an individual patient’s treatment plan, while retaining the SGLT-2i cardiorenal benefits for effective disease management. Recognition by physicians that the benefits of SGLT-2i use on clinical outcomes outweigh the risks will result in the integration of SGLT-2is into clinical practice and lead to improved patient care and outcomes

    Relationship between casting modulus and grain size in cast A356 aluminium alloys

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    Microstructure of Al-Si alloy castings depends most generally on melt preparation and on the cooling rate imposed by the thermal modulus of the component. In the case of Al-Si alloys, emphasis is put during melt preparation on refinement of pro-eutectic (Al) grains and on modification of the Al-Si eutectic. Thermal analysis has been used since long to check melt preparation before casting, i.e. by analysis of the cooling curve during solidification of a sample cast in an instrumented cup. The conclusions drawn from such analysis are however valid for the particular cooling conditions of the cups. It thus appeared of interest to investigate how these conclusions could extrapolate to predict microstructure in complicated cast parts showing local changes in the solidification conditions. For that purpose, thermal analysis cups and instrumented sand and die castings with different thermal moduli and thus cooling rates have been made, and the whole set of cooling curves thus recorded has been analysed. A statistical analysis of the characteristic features of the cooling curves related to grain refinement in sand and die castings allowed determining the most significant parameters and expressing the cube of grain size as a polynomial of these parameters. After introduction of a further parameter quantifying melt refining an excellent correlation, with a R2 factor of 0.99 was obtained

    Near-unity broadband omnidirectional emissivity via femtosecond laser surface processing

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    It is very challenging to achieve near perfect absorption/emission that is both broadband and omnidirectional while utilizing a scalable fabrication process. Femtosecond laser surface processing is an emerging low-cost and large-scale manufacturing technique used to directly and permanently modify the surface properties of a material. The versatility of this technique to produce tailored surface properties has resulted in a rapidly growing number of applications. Here, we demonstrate near perfect, broadband, omnidirectional emissivity from aluminum surfaces by tuning the laser surface processing parameters including fluence, pulse count, and the ambient gas. Full-wave simulations and experimental results prove that the obtained increase in emissivity is mainly a result of two distinct features produced by femtosecond laser surface processing: the introduction of microscale surface features and the thick oxide layer. This technique leads to functionalized metallic surfaces that are ideal for emerging applications, such as passive radiative cooling and thermal management of spacecraft
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