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ℋ∞ leader-following consensus of multi-agent systems with channel fading under switching topologies: a semi-Markov kernel approach
No full textThis paper focuses on the leader-following consensus problem of discrete-time multi-agent systems subject to channel fading under switching topologies. First, a topology switching-based channel fading model is established to describe the information fading of the communication channel among agents, which also considers the channel fading from leader to follower and from follower to follower. It is more general than models in the existing literature that only consider follower-to-follower fading. For discrete multi-agent systems, the existing literature usually adopts time series or Markov process to characterize topology switching while ignoring the more general semi-Markov process. Based on the advantages and properties of semi-Markov processes, discrete semi-Markov jump processes are adopted to model network topology switching. Then, the semi-Markov kernel approach for handling discrete semi-Markov jumping systems is exploited and some novel sufficient conditions to ensure the leader-following mean square consensus of closed-loop systems are derived. Furthermore, the distributed consensus protocol is proposed by means of the stochastic Lyapunov stability theory so that the underlying systems can achieve ℋ∞ consensus performance index. In addition, the proposed method is extended to the scenario where the semi-Markov kernel of semi-Markov switching topologies is not completely accessible. Finally, a simulation example is given to verify the results proposed in this paper. Compared with the existing literature, the method in this paper is more effective and general
Regional deposited dose in the human respiratory tract using different particulate metrics
No full textThe objective of the current study was to calculate the deposited dose rate in the human respiratory tract arising from particle number (PN) and particle mass (PM) measurements. A main objective was the investigation of deposition pattern and characteristics of the two metrics in the human respiratory tract. The dose rate was estimated for residents at a suburban background location (Chania, Greece). The total dose rate showed two peaks, one in the morning (1.6 × 109 particles/h at 7:00-8:00) and the other one at night (2.1 × 109 particles/h at 21:00-22:00), during the warm period, while the cold period showed two peaks, morning (2.0 × 109 particles/h at 9:00-10:00) and afternoon (3.6 × 109 particles/h at 18:00-19:00). The peaks during the warm period were associated with traffic emissions, whereas the peaks during the cold period were associated with both heating and traffic emissions. A higher dose rate of PN10 was found in the alveolar region while for PM10 it was found in the extrathoracic region. These findings are linked with increased contribution of ultrafine and coarse particles to PN10 (65%-78% and 54%-62% for cold and warm periods, respectively) and PM10 (63% and 55% for cold and warm periods, respectively) concentrations, respectively. The current study showed the importance to use both number and mass aerosol metrics for determining the human exposure and regional dose and their related health effects. The novelty of the current study is the simultaneous measurements of the two particles metrics and the full particle size distributions to make accurate estimates of regional deposited dose
A One Health perspective on water contaminants
No full textOne Health is a transdisciplinary approach considering human, animal, and environmental health, and is highly relevant to water management. The growing pressure of anthropogenic activities is leading to water contamination with biological, chemical, and physical contaminants. For example, pathogens may result from fecal contamination due to poor sanitation or livestock waste leachate, agrochemicals from intensive agricultural practices, sediments from soil erosion, or microplastics from a wide range of anthropogenic activities. These activities can have widespread impacts, as exemplified by nitrates leaching from agricultural fields to surface and drinking waters, which can impact human health (e.g., methemoglobinemia), animal health (e.g., abortions and hypoxia), and environmental health (e.g., eutrophication). Recommendations include an integrated One Health approach to water contamination prevention: (i) respect for sociocultural practices; (ii) improved land management; (iii) improved infrastructures for water and wastewater management; (iv) surveillance of water bodies; (v) improved agricultural practices; and (vi) prevention through environmental management systems
Robotic donor hepatectomy: a niche advancement or the way forward? A perspective from the world’s largest center
No full textThe application of minimally invasive liver surgery (MILS) in the field of living donor hepatectomy has been exceedingly slow, and its impact is limited to a handful of centers worldwide. Widespread adoption has been primarily hampered by the technical limitations of laparoscopy, namely rigid instrumentation, suboptimal optics, and a seemingly steep learning curve. These deficiencies are magnified in the donor hepatectomy operation wherein the parenchyma and vasculature must be handled atraumatically to produce a pristine allograft fit for implantation. Donor safety concerns and medicolegal ramifications are also cited as impediments to MILS in donor surgery. In 2013, our institution embraced a purely laparoscopic approach to living donor left lateral sectionectomy, and it quickly became our default technique. However, with donor hemi-hepatectomy, we gravitated to the robotic surgical system as our preferred modality. Herein, we describe our experience with minimally invasive donor hepatectomy, which we now universally offer to all living donors. Our extensive familiarity with robotic donor hepatectomy will provide the reader with an instructive perspective on the attributes and merits of the robotic approach. With appropriate collaboration and proctorship, we believe that the robotic platform will actualize a more rapid and widespread adoption than that experienced with the purely laparoscopic technique
Echocardiography: an overview - Part II
No full textThis review describes echocardiographic features of commonly encountered acyanotic congenital heart defects. Echo-Doppler features of lesions causing obstruction, namely aortic stenosis, aortic coarctation, stenosis of the pulmonary valve and pulmonary arteries were initially presented followed by discussion of lesions with left-to-right shunt namely, atrial and ventricular septal defects, patent foramen ovale, patent ductus arteriosus (PDA), and atrioventricular septal defect. A special section dedicated to evaluating hemodynamically significant PDAs in premature infants was also included. Coronary artery anomalies (both congenital and acquired) were reviewed at the conclusion of the paper
Open repair for thoracoabdominal aortic aneurysms precipitated by chronic aortic dissection
No full textChronic dissection of the thoracoabdominal aorta may require surgical repair for aneurysm, malperfusion, or rupture. Endovascular repair is made difficult by a noncompliant dissection septum, visceral vessels arising from different lumens, and the common use of diseased aortic landing zones. Thus, open repair remains the gold standard in terms of favorable outcomes and durability. During thoracoabdominal aortic repair, we use a multimodal strategy to prevent spinal cord and visceral or renal artery ischemia; key modalities include cerebrospinal fluid drainage, left heart bypass with and without visceral protection, cold renal protection, and aggressive reimplantation of intercostal or lumbar arteries. Patients with chronic dissection require lifelong surveillance, as there is a significant risk for subsequent intervention on unrepaired aortic segments
Clinico-pathophysiological considerations in coronary microvascular disorders
No full textAround half of the patients undergoing an elective coronary angiogram to investigate typical stable angina symptoms are found to have non-obstructive coronary arteries (defined as < 50% stenosis). These patients are younger with a female predilection. While underlying mechanisms responsible for these presentations are heterogeneous, structural and functional abnormalities of the coronary microvasculature are highly prevalent. Thus, coronary microvascular dysfunction (CMD) is increasingly recognised as an important consideration in patients with non-obstructive coronary arteries. This review will focus on primary coronary microvascular disorders and summarise the four common clinical presentation pictures which can be considered as endotypes - Microvascular Ischaemia (formerly “Syndrome X”), Microvascular Angina, Microvascular Spasm, and Coronary Slow Flow. Furthermore, the pathophysiological mechanisms associated with CMD are also heterogenous. CMD may arise from an increased microvascular resistance, impaired microvascular dilation, and/or inducible microvascular spasm, ultimately causing myocardial ischaemia and angina. Alternatively, chest pain may arise from hypersensitivity of myocardial pain receptors rather than myocardial ischaemia. These two major abnormalities should be considered when assessing an individual clinical picture, and ultimately, the question arises whether to target the heart or the pain perception to treat the anginal symptoms
Tips for difficult colorectal endoscopic submucosal dissection
No full textColorectal endoscopic submucosal dissection (ESD) is now widely performed and firmly established in the treatment of early-stage colorectal cancer. In particular, there have been many studies on difficult cases of colorectal ESD. Difficult cases can be divided into two groups: difficult dissection of the lesions and difficult approach to the lesion. In most cases, a combination of strategies can solve the problem. Challenging lesions such as those in the anal canal and ileum can also be treated from an anatomical perspective. In the rectum, there are no limits to size or circumference. In addition, the indications for ESD in patients without risk of metastasis other than deep invasion are being considered. Therefore, when ESD is performed on difficult lesions, it is necessary to ensure the quality of dissection
Trifecta results in Retzius-sparing robotic radical prostatectomy: results of a high-volume center
No full textAim: We aimed to evaluate trifecta outcomes after Retzius-sparing robot-assisted radical prostatectomy (rs-RARP).Methods: We evaluated 1488 patients who had undergone rs-RARP at our institution from 2011 to 2019. All patients filled out questionaries for functional outcomes before surgery, and only patients with baseline continence and IIEF-5 scores of > 16 were included. Biochemical recurrence (BCR) was defined as two consecutive prostatic specific antigen levels of > 0.2 ng/mL after rs-RARP. Postoperative continence was defined as the use of no pads. Potency was defined as the ability to achieve erections for sexual intercourse, with or without phosphodiesterase-5 (PDE-5) inhibitors. A multivariable logistic regression model was performed to identify predictors of trifecta outcome.Results: In total, 1240 patients were included in the analysis. During the 24-month follow-up time, 149 patients (11.9%) harbored BCR. Urinary continence was observed in 981 patients (79.5%), while 171 (13.8%) still used a safety pad daily after 24 months. Sexual potency was reported in 643 patients (51.9%), of whom 379 (30.6%) had spontaneous erections and 264 (21.3%) used a PDE-5 inhibitor. Overall, the trifecta outcome was reached by 42.1% of the study’s population. The trifecta outcome was easily reached by younger patients and patients who underwent a full nerve-sparing (NS) prostatectomy. In the multivariable model, age [odds ratio (OR) = 0.89; 95% confidence interval (CI): 0.84-0.90; P < 0.01] and type of NS surgery [partial NS (OR = 3.34; 95%CI: 1.01-11; P = 0.04) full NS (OR = 4.57; 95%CI: 1.86-12; P < 0.01)] resulted as independent predictors.Conclusion: rs-RARP is associated with optimal trifecta outcome rate. Age and NS technique are independent predictors of trifecta outcomes
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