Reconfigurable microstrip filter with continuous coupling and frequency tunability

Thesis (MEng)--Stellenbosch University, 2021.ENGLISH ABSTRACT: For the modern communication system, adaptability is an essential requirement to remain relevant in the current day and age. This project focuses on the implementation of a varactor structure to provide a method of controlling the coupling in coupled-resonator filters. This will allow a single filter to preform the task of multiple set bandwidth filters and allow a single filter to adapt to new requirements when needed. The coupling structure in this project is used to limit the magnetic coupling strength so that the dominant coupling type is electrical and uses the structure placement and choice of resonator to achieve the required tuning range. The coupling structure can control the pass-band bandwidth to change from 300 MHz to 600 MHz with a center frequency tuning range of 2 -3.5 GHz and 3.36 to 2.75 GHz. This project uses ideal transmission line models and simulation software like CST and AWR to determine the characteristics of the filter. The coupling structure adds an insertion loss zero and pole. By means of good design choices the pole can limit the zeros' influence on the pass-band. Measurements show that the models predicted the characteristics with good accuracy, however an increase in loss due to the varactor is observed in measurement. The project did show that the use of the varactor structure provides a good method of controlling the coupling strengthAFRIKAANSE OPSOMMING: Vir die moderne kommunikasiestelsel is aanpasbaarheid 'n noodsaaklike vereiste om op die huidige tyd relevant te bly. Die projek fokus op die implementering van 'n varaktorstruktuur om 'n metode te bied om die koppelsterkte in gekoppelde resonerende filter te beheer. Die koppelstruktuur word gebruik om die magnetiese koppelsterkte te beperk sodat die dominante koppelingstipe elektries is. Die in- vloed van die plasing van die koppelstruktuur op 'n mikrostrook resoneerder sal getoets en bespreek word om te bepaal wat nodig is vir 'n spesifieke verstelbaar- heid. Die koppelstruktuur kan die deurlaatband reguleer om van 300 MHz na 600 MHz met die middel frekwensie verstelbarheid van 2 -3.5 GHz en 3.36 to 2.75 GHz. Hierdie projek maak gebruik van ideale transmissielyn modelle en simulasiesagte- ware soos CST en AWR om die eienskappe van die filter akkuraat te bepaal. Die koppelstruktuur wys dat dit 'n invoegverlies zero en pool toevoeg, en met goeie ontwerpkeuses kan die pole die invloed van die zero op die deurlaatband beperk. Metings toon dat die modelle die eienskappe met goeie akkuraatheid voorspel het, maar as gevolg van die varaktormodel wat vir hierdie projek gebruik word, is die verlies meer in werklikheid as in simulasie. Die projek het getoon dat die gebruik van die varaktorstruktuur 'n goeie metode bied om die koppelsterkte te beheer.Master

Preoperative iron treatment in anaemic patients undergoing elective total hip or knee arthroplasty : a systematic review and meta-analysis

Objectives: Preoperative anaemia is associated with increased risks of postoperative complications, blood transfusion and mortality. This meta-analysis aims to review the best available evidence on the clinical effectiveness of preoperative iron in anaemic patients undergoing elective total hip (THR) or total knee replacement (TKR). Design: Electronic databases and handsearching were used to identify randomised and non-randomised studies of interventions (NRSI) reporting perioperative blood transfusion rates for anaemic participants receiving iron before elective THR or TKR. Searches of CENTRAL, MEDLINE, Embase, PubMed and other databases were conducted on 17 April 2019 and updated on 15 July 2020. Two investigators independently reviewed studies for eligibility and evaluated risk of bias using the Cochrane risk of bias tool for randomised controlled trials (RCTs) and a modified Newcastle-Ottawa scale for NRSIs. Data extraction was performed by ABS and checked by AB. Meta-analysis used the Mantel-Haenszel method and random-effects models. Results: 807 records were identified: 12 studies met the inclusion criteria, of which 10 were eligible for meta- analyses (one RCT and nine NRSIs). Five of the NRSIs were of high-quality while there were some concerns of bias in the RCT. Meta-analysis of 10 studies (n=2178 participants) showed a 39% reduction in risk of receiving a perioperative blood transfusion with iron compared with no iron (risk ratio 0.61, 95% CI 0.50 to 0.73, p<0.001, I2=0%). There was a significant reduction in the number of red blood cell units transfused with iron compared with no iron (mean difference −0.37units, 95% CI −0.47 to 2-0.27, p<0.001, I =40%); six studies (n=1496). Length of stay was significantly reduced with iron, by an average of 2.08 days (95% CI −2.64 to −1.51, p<0.001, I2=40%); five studies (n=1140). Conclusions: Preoperative iron in anaemic, elective THR or TKR patients, significantly reduces the number of patients and number of units transfused and length of stay. However, high-quality, randomised trials are lacking. PROSPERO registration number CRD42019129035

Integration of robotic surgery into routine practice and impacts on communication, collaboration, and decision making: A realist process evaluation protocol

Background: Robotic surgery offers many potential benefits for patients. While an increasing number of healthcare providers are purchasing surgical robots, there are reports that the technology is failing to be introduced into routine practice. Additionally, in robotic surgery, the surgeon is physically separated from the patient and the rest of the team, with the potential to negatively impact teamwork in the operating theatre. The aim of this study is to ascertain: how and under what circumstances robotic surgery is effectively introduced into routine practice; and how and under what circumstances robotic surgery impacts teamwork, communication and decision making, and subsequent patient outcomes. Methods and design: We will undertake a process evaluation alongside a randomised controlled trial comparing laparoscopic and robotic surgery for the curative treatment of rectal cancer. Realist evaluation provides an overall framework for the study. The study will be in three phases. In Phase I, grey literature will be reviewed to identify stakeholders' theories concerning how robotic surgery becomes embedded into surgical practice and its impacts. These theories will be refined and added to through interviews conducted across English hospitals that are using robotic surgery for rectal cancer resection with staff at different levels of the organisation, along with a review of documentation associated with the introduction of robotic surgery. In Phase II, a multi-site case study will be conducted across four English hospitals to test and refine the candidate theories. Data will be collected using multiple methods: the structured observation tool OTAS (Observational Teamwork Assessment for Surgery); video recordings of operations; ethnographic observation; and interviews. In Phase III, interviews will be conducted at the four case sites with staff representing a range of surgical disciplines, to assess the extent to which the results of Phase II are generalisable and to refine the resulting theories to reflect the experience of a broader range of surgical disciplines. The study will provide (i) guidance to healthcare organisations on factors likely to facilitate successful implementation and integration of robotic surgery, and (ii) guidance on how to ensure effective communication and teamwork when undertaking robotic surgery

STUDY PROTOCOL Open Access

Integration of robotic surgery into routine practice and impacts on communication, collaboration, and decision making: a realist process evaluation protoco

Scaling Up Quality Improvement for Surgical Teams (QIST) - avoiding surgical site infection and anaemia at the time of surgery: a cluster randomised controlled trial of the effectiveness of quality improvement collaboratives to introduce change in the NHS

Background The aim of this trial was to assess the effectiveness of quality improvement collaboratives to implement large-scale change in the National Health Service (NHS) in the United Kingdom, specifically for improving outcomes in patients undergoing primary, elective total hip or knee replacement. Methods We undertook a two arm, cluster randomised controlled trial comparing the roll-out of two preoperative pathways: Methicillin-sensitive Staphylococcus Aureus (MSSA) decolonisation (infection arm); and anaemia screening and treatment (anaemia arm). NHS Trusts are public sector organisations that provide healthcare within a geographical area. NHS Trusts (n=41) in England providing primary, elective total hip and knee replacements, but that did not have a preoperative anaemia screening or MSSA decolonisation pathway in place, were randomised to one of the two parallel collaboratives. Collaboratives took place from May 2018 to November 2019. Twenty-seven Trusts completed the trial (11 anaemia, 16 infection). Outcome data were collected for procedures performed between November 2018 and November 2019. Co-primary outcomes were perioperative blood transfusion (within 7 days of surgery) and deep surgical site infection (SSI) caused by MSSA (within 90 days post-surgery) for the anaemia and infection trial arms respectively. Secondary outcomes were deep and superficial SSIs (any organism), length of hospital stay, critical care admissions, and unplanned readmissions. Process measures included the proportion of eligible patients receiving each preoperative initiative. Results There were 19,254 procedures from 27 NHS Trusts included in the results (6,324 from 11 Trusts in the anaemia arm, 12,930 from 16 Trusts in the infection arm). There were no improvements observed for blood transfusion (anaemia arm 183 (2.9%); infection arm 302 (2.3%) transfusions; adjusted odds ratio 1.20, 95% CI 0.52-2.75, p=0.67) or MSSA deep SSI (anaemia arm 8 (0.13%); infection arm 18 (0.14%); adjusted odds ratio 1.01, 95% CI 0.42-2.46, p=0.98). There were no significant improvements in any secondary outcome. This is despite process measures showing the preoperative pathways were implemented for 73.7% and 61.1% of eligible procedures in the infection and anaemia arms respectively. Conclusions Quality improvement collaboratives did not result in improved patient outcomes in this trial; however, there was some evidence they may support successful implementation of new preoperative pathways in the NHS