Heterodyne Array Receivers for Space and Ground Based Applications

The first heterodyne array receivers have been successfully built for ground-based telescopes and airborne observatories. In the talk we give a very quick overview of some prior heterodyne arrays. In particular, we will look at the innovations they introduced and how these could be applied to future large (100 to 1000 pixel) arrays or space missions. Then we will present the first detailed design for a space application, the Heterodyne Receiver for the Origins Space Telescope (HERO). HERO follows the traditional design, but limited cooling power and the limited electrical power of the satellite pose major challenges. Minor challenges are limited availability of space and weight. For the eight 3x3 pixel arrays of which 4 can operate simultaneously we attributed 20mW at 4.5K, 35mW at 35K and 205 W at the satellite temperature. Therefore we propose to use SiGe cryogenic low noise amplifiers, with a dissipation of about 0.5mW for 6 GHz bandwidth. The power of the backends also needs to be reduced drastically to about 1 W for 6 GHz bandwidth. CMOS ASIC backends are one option, ADC, followed by FFTs and ACCs another. To reduce the volume and mass, we propose the cover the RF bandwidth of 486 GHz to 2700 GHz in only 4 bands, each with about 50% relative width.The design might not only be a helpful starting point for any heterodyne array on a satellite, but the low heat and power consumption might be also an essential first step for large (100 to 1000 pixels) heterodyne arrays for ground based telescopes or simply a more energy efficient alternative for any ALMA single pixel or array receiver

Initial Report of a New Suture Cerclage Tape for Sternal Closure

PURPOSE: We sought to evaluate a new, flexible suture cerclage tape for sternal closure after cardiac surgery. DESCRIPTION: Fiber Tape (Arthrex, Naples, FL, USA) suture cerclage has been successfully utilized in the stabilization of long bone fractures. For sternal closure, it is placed similarly to wire cerclage. Uniquely, it allows a measurable amount of tension to be applied to the sternum and it is at least twice as strong as stainless steel wire. We hypothesized this new flexible tape would provide short term safety and efficacy, as measured by incidence of deep sternal wound infection. EVALUATION: We performed a retrospective, single center analysis of adult patients undergoing sternotomy closure with FT. The observed incidence of deep sternal wound infection (DSWI) was compared to the expected incidence calculated through the Society of Thoracic Surgery (STS) risk calculator. A total of 45 patients were closed with FT. No patients suffered DSWI. Thirty of the 45 patients had STS risk calculations. For these 30 patients, the expected rate of DSWI was 0.2%. CONCLUSIONS: Despite study limitations, FT appears to be a safe method for sternal closure.</jats:p

Real world outcomes of minimally invasive epicardial surgical left atrial appendage exclusion in atrial fibrillation patients with high risk of stroke and bleeding

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): AtriCure, Inc Introduction The left atrial appendage (LAA) is the site of thrombus formation in patients with atrial fibrillation (AF) and first line therapy for reducing the risk of stroke is oral anticoagulation (OACs). A subset of patients with AF carry a very high risk of stroke and bleeding and are ineligible for OAC and percutaneous LAA occlusion; these patients may be suitable for minimally invasive thoracoscopic epicardial surgical LAA exclusion (LAAE) which can be used with a wide variety of LAA morphologies with a ~98% rate of complete exclusion. While use of LAAE is well studied as a concomitant procedure, there are relatively few data on its use as a stand-alone procedure. Purpose To compare real-world outcomes of LAAE versus no-LAAE in AF patients at high risk of stroke and bleeding who are not on OACs. Methods We performed an analysis of Medicare beneficiaries with AF who were not on OACs and received LAAE (ICD10-PCS code 02L74CK, Oct 2015 – Dec 31, 2017) in the absence of a concomitant surgical or catheter AF ablation procedure. Patients were propensity-matched (1:4) to otherwise similar patients who did not receive LAAE (control), using age, gender, race, region, AF type, CHA2DS2-VASc, HAS-BLED, and co-morbidities. The primary endpoint was hospital readmission for a thromboembolic event (ischemic stroke, systemic embolism, or transient ischemic attack). Kaplan Meier event rates were calculated and 95% CI were generated via bootstrapping. Results A total of 243 patients who underwent LAAE and 1.7M control patients met study criteria. In the matched cohort, the mean age was 75 years, 61% were men, 77% had non-paroxysmal AF, and the mean CHADS2-VASC and HAS-BLED scores were 5.5 and 4.2, respectively. The 1-year rate of thromboembolism in the LAAE and control arms were 7.3% (95% CI 4.3% -10.9%) and 13.6 (95% CI 11.0% -16.4%) (Figure), respectively, with an absolute and relative risk reduction of 6.2% (95% CI 2.0-10.3, p-value=0.001, NNT 17) and 0.54 (95% CI 0.29-0.68, p=0.001). Conclusion Among high-risk AF patients who were not on OAC, LAAE was associated with a clinically meaningful and significantly lower risk of TE. Additional studies are needed to confirm these finding. </jats:sec

Myocardial Protection and Financial Considerations of Custodiol Cardioplegia in Minimally Invasive and Open Valve Surgery

Objective Single-dose antegrade crystalloid cardioplegia with Custodiol-HTK (histidine-tryptophan-ketoglutarate) has been used for many years. Its safety and efficacy were established in experimental and clinical studies. It is beneficial in complex valve surgery because it provides a long period of myocardial protection with a single dose. Thus, valve procedures (minimally invasive or open) can be performed with limited interruption. The aim of this study is to compare the use of Custodiol-HTK cardioplegia with traditional blood cardioplegia in patients undergoing minimally invasive and open valve surgery. Methods A single-institution, retrospective case-control review was performed on patients who underwent valve surgery in Lee Memorial Health System at either HealthPark Medical Center or Gulf Coast Medical Center from July 1, 2011, through March 7, 2015. A total of 181 valve cases (aortic or mitral) performed using Custodiol-HTK cardioplegia were compared with 181 cases performed with traditional blood cardioplegia. Each group had an equal distribution of minimally invasive and open valve cases. Right chest thoracotomy or partial sternotomy was performed on minimally invasive valve cases. Demographics, perioperative data, clinical outcomes, and financial data were collected and analyzed. Results Patient outcomes were superior in the Custodiol-HTK cardioplegia group for blood transfusion, stroke, and hospital readmission within 30 days (P &lt; 0.05). No statistical differences were observed in the other outcomes categories. Hospital charges were reduced on average by $3013 per patient when using Custodiol-HTK cardioplegia. Conclusions Use of Custodiol-HTK cardioplegia is safe and cost-effective when compared with traditional repetitive blood cardioplegia in patients undergoing minimally invasive and open valve surgery. </jats:sec

Heterodyne Array Receivers for Space and Ground Based Applications

The first heterodyne array receivers have been successfully built for ground-based telescopes and airborne observatories. In the talk we give a very quick overview of some prior heterodyne arrays. In particular, we will look at the innovations they introduced and how these could be applied to future large (100 to 1000 pixel) arrays or space missions. Then we will present the first detailed design for a space application, the Heterodyne Receiver for the Origins Space Telescope (HERO). HERO follows the traditional design, but limited cooling power and the limited electrical power of the satellite pose major challenges. Minor challenges are limited availability of space and weight. For the eight 3x3 pixel arrays of which 4 can operate simultaneously we attributed 20mW at 4.5K, 35mW at 35K and 205 W at the satellite temperature. Therefore we propose to use SiGe cryogenic low noise amplifiers, with a dissipation of about 0.5mW for 6 GHz bandwidth. The power of the backends also needs to be reduced drastically to about 1 W for 6 GHz bandwidth. CMOS ASIC backends are one option, ADC, followed by FFTs and ACCs another. To reduce the volume and mass, we propose the cover the RF bandwidth of 486 GHz to 2700 GHz in only 4 bands, each with about 50% relative width.The design might not only be a helpful starting point for any heterodyne array on a satellite, but the low heat and power consumption might be also an essential first step for large (100 to 1000 pixels) heterodyne arrays for ground based telescopes or simply a more energy efficient alternative for any ALMA single pixel or array receiver