High-frequency two-input CMOS OTA for continuous-time filter applications

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”A high-frequency fully differential CMOS operational transconductance amplifier (OTA) is presented for continuous-time filter applications in the megahertz range. The proposed design technique combines a linear cross-coupled quad input stage with an enhanced folded-cascode circuit to increase the output resistance of the amplifier. SPICE simulations show that DC-gain enhancement can be obtained without significant bandwidth limitation. The two-input OTA developed is used in high-frequency tuneable filter design based on IFLF and LC ladder simulation structures. Simulated results of parameters and characteristics of the OTA and filters in a standard 1.2 μm CMOS process (MOSIS) are presented. A tuning circuit is also discussed.Peer reviewe

Total intracorporeal robot kidney autotransplantation : case report and description of surgical technique

Introduction and Objectives: Kidney autotransplantation can be performed in patients with complex renal or ureteral pathology not suitable for in situ reconstruction, such as renal vasculature anomalies, patients with proximal or long complex ureteral strictures, or complex oncological cases. Robot-assisted surgery allows for a high-quality vascular and ureteral anastomosis and faster patient recovery. Robot-assisted kidney autotransplantation (RAKAT) is performed in two phases: nephrectomy and pelvic transplantation. In-between, extraction of the kidney allows for vascular reconstruction or kidney modification on the bench and safe cold ischemia can be established. If no bench reconstruction is needed, total intracorporeal RAKAT (tiRAKAT) is feasible. One case report in Europe has been described; however, to our knowledge no surgical video is available. Methods: A 58 year-old woman suffered from right mid- and distal ureteral stenosis following pelvic radiotherapy 10 years prior for cervical cancer. A JJ stent was placed, but she suffered from recurrent urinary tract infections, and ultimately a nephrostomy was placed. Renogram demonstrated 43% relative right kidney function. As her bladder volume was low following radiotherapy, no Boari flap was possible and the patient refused life-long nephrostomy or nephrectomy. Therefore, tiRAKAT was performed using the DaVinci Xi system. Results: We describe our surgical technique including a video. Surgical time (skin-to-skin) was 5 h and 45 min. Warm ischemia time was 4 min, cold ischemia 55 min, and rewarming ischemia 15 min. The abdominal catheter and bladder catheter were removed on the first and second postoperative day, respectively. The JJ stent was removed after 4 weeks. The patient suffered from pulmonary embolism on the second postoperative day, for which therapeutic low molecular weight heparin was started. No further complications occurred during the first 90 postoperative days. After 7 months, overall kidney function remained stable, right kidney function dropped non-significantly from 27 to 25.2 mL/min (-6.7%) on renal scintigraphy. Conclusion: We demonstrated feasibility and, for the first time, a surgical video of tiRAKAT highlighting patient positioning, trocar placement, and intracorporeal cold ischemia technique

Extending additivity from symmetric to asymmetric channels

We prove a lemma which allows one to extend results about the additivity of the minimal output entropy from highly symmetric channels to a much larger class. A similar result holds for the maximal output $p$-norm. Examples are given showing its use in a variety of situations. In particular, we prove the additivity and the multiplicativity for the shifted depolarising channel.Comment: 8 pages. This is the latest version of the first half of the original paper. The other half will appear in another pape

On hydrogen bond correlations at high pressures

In situ high pressure neutron diffraction measured lengths of O H and H O pairs in hydrogen bonds in substances are shown to follow the correlation between them established from 0.1 MPa data on different chemical compounds. In particular, the conclusion by Nelmes et al that their high pressure data on ice VIII differ from it is not supported. For compounds in which the O H stretching frequencies red shift under pressure, it is shown that wherever structural data is available, they follow the stretching frequency versus H O (or O O) distance correlation. For compounds displaying blue shifts with pressure an analogy appears to exist with improper hydrogen bonds.Comment: 12 pages,4 figure

Single-setting robot-assisted kidney transplantation consecutive to single-port laparoscopic nephrectomy in a child and robot-assisted living-related donor nephrectomy : initial Ghent experience

Introduction Kidney transplantation (KT) is the gold-standard treatment for end-stage renal disease (ESRD) in children. Robot-assisted kidney transplantation (RAKT) in adults is becoming increasingly common with potentially improved morbidity compared with open KT. The study objective was to evaluate feasibility and outcomes of RAKT in children. Patients & methods An 8-years-old boy with ESRD received a kidney transplant from his mother. Simultaneously in two operation theatres, the boy underwent single-port (GeIPOINT (R)) right laparoscopic nephroureterectomy (LNU), and his mother underwent robot-assisted left donor nephrectomy (RADN).Two full surgical teams were operating at the same time. Subsequently, the boy underwent RAKT, introducing the graft through the GeIPOINT (R). Results Total operative time for LNU, RADN, and RAKT was 180, 140, and 195 min, respectively, with warm, cold, and rewarming ischemia times 1.5, 200, and 47 min, respectively. Blood loss was 300, 20, and 50 cc, respectively. No intraoperative complications were noted. Convalescence of both donor and recipient was uneventful, with good kidney function at 1-year follow-up. Conclusion RAKT in children is technically feasible and safe, resulting in excellent graft function. Concomitant nephrectomy can be done laparoscopically through the single-site GeIPOINT (R). An experienced RAKT team with the full support of pediatric nephrologists is mandatory

Pediatric challenges in robot-assisted kidney transplantation

Kidney transplantation is universally recognized as the gold standard treatment in patients with End-stage Kidney Disease (ESKD, or according to the latest nomenclature, CKD stage 5). Robot-assisted kidney transplantation (RAKT) is gradually becoming preferred technique in adults, even if applied in very few centra, with potentially improved clinical outcomes compared with open kidney transplantation. To date, only very few RAKT procedures in children have been described. Kidney transplant recipient patients, being immunocompromised, might be at increased risk for perioperative surgical complications, which creates additional challenges in management. Applying techniques of minimally invasive surgery may contribute to the improvement of clinical outcomes for the pediatric transplant patients population and help mitigate the morbidity of KT. However, many challenges remain ahead. Minimally invasive surgery has been consistently shown to produce improved clinical outcomes as compared to open surgery equivalents. Robot-assisted laparoscopic surgery (RALS) has been able to overcome many restrictions of classical laparoscopy, particularly in complex and demanding surgical procedures. Despite the presence of these improvements, many challenges lie ahead in the surgical and technical-material realms, in addition to anesthetic and economic considerations. RALS in children poses additional challenges to both the surgical and anesthesiology team, due to specific characteristics such as a small abdominal cavity and a reduced circulating blood volume. Cost-effectiveness, esthetic and functional wound outcomes, minimal age and weight to undergo RALS and effect of RAKT on graft function are discussed. Although data on RAKT in children is scarce, it is a safe and feasible procedure and results in excellent graft function. It should only be performed by a RAKT team experienced in both RALS and transplantation surgery, fully supported by a pediatric nephrology and anesthesiology team. Further research is necessary to better determine the value of the robotic approach as compared to the laparoscopic and open approach. Cost-effectiveness will remain an important subject of debate and is in need of further evaluation as well