This paper analyses Disturbance Observer- (DOb-) based robust force control systems in the discrete-time domain. The robust force controller is implemented using velocity and acceleration measurements. A DOb is employed in an inner-loop to achieve robustness, and another DOb, viz. Reaction Force Observer (RFOb), is employed in an outer-loop to estimate interaction forces and improve the performance of force control. First, the inner-loop is analysed. It is shown that the DOb works as a phase-lead/lag compensator tuned by the nominal design parameters in the inner-loop. The phase margin of the inner-loop controller and the bandwidth of the velocity-based (i.e., conventional) DOb are constrained not only by noise-sensitivity but also by the waterbed effect. This explains why we observe unstable responses as the bandwidth of the conventional DOb increases in practice. To eliminate the design constraint due to the waterbed effect, this paper proposes an acceleration-based DOb. Then, the robust force controller is analysed. It is shown that the design parameters of the RFOb have a notable effect on the stability of the robust force control system. For example, the robust force controller has a non-minimum phase zero (zeros) when the RFOb is not properly tuned. This may cause severe stability and performance problems when conducting force control applications. By using the stability and robustness analyses, this paper proposes new design tools which enable one to synthesize a high-performance robust force control system. Simulations and experiments are presented to validate the proposed analysis and synthesis methods.

Bringing deep learning techniques to electromagnetic imaging is of interest considering its great success in various fields. Deep neural nets however are known for being data hungry machines, and in many practical cases, such as electromagnetic medical imaging, there is not enough to feed them. Scarcity of data necessitates reliance on simulations to generate a sufficiently large dataset for deep learning to perform any complicated task. Simulations however, can not perfectly represent real environments and therefore, any neural net trained on simulation data will invariably fail when evaluated on real data. This work customizes a deep domain adaptation technique for matching distributions of complex-valued electromagnetic data. We demonstrate the advantage of using complex-valued models over regular ones. An operational neural network trained on simulation data and adapted to practical data to perform brain injury localization is presented.

The main intention of this paper is to explore the possibility of positioning the discourse on adult identity formation within the context of higher education. To this end, first formational potential of higher education is revisited. Further on, Eriksonian psychosocial theoretical approach and Arnett's concept of emerging adulthood are proposed as the referential framework for conceptualizing adult identity formation processes. It is concluded that by offering instituzionalized moratorium and the possibility for the extended transition from adolescence to adulthood, higher education context provides intensive identity work opportunities. However, in dominant discourses, higher education's humanistic ends have been suppressed by economistic and utilitarian objectives. Therefore, this paper also urges revitalizing higher education's humanistic values by exploring personal growth posibilities.

Coronavirus Disease 2019 (COVID-19), caused by the novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), persists as a threat to global health and continues to be a rapidly evolving condition. Although COVID19 is negatively correlated with the existing comorbidities in terms of the clinical outcome, the ability of SARS-CoV-2 to mediate the novel, or to exacerbate the existing autoimmune conditions, has generated considerable interest, due to its potential implications both with regard to patients suffering from autoimmune conditions, as well as to the long-term consequences of the disease. However, although molecular mimicry has been postulated as a potential causative factor in post-COVID19 autoimmunity and multi-organ damage, a substantial body of research needs to emerge in order to achieve a more definitive conclusion. We investigated the possibility of SARS-CoV-2 peptide sequences behaving as molecular mimics with a potential to trigger an autoimmune response. Thus, on the basis of analysis in silico, we were able to develop a plausible case for the molecular mimicry as a potential aetiological mechanism of SARS-CoV-2-mediated autoimmunity, both in a multi-organ damage context or outside of the viral phase of infection. Interestingly, this is the first time that the peptide sequence of MACROD1 has been implicated in the COVID-19 autoimmunity. Additionally, we also confirm that PARP9 and PARP14 may be involved in the process.

For validation and demonstration of high accuracy ranging and positioning algorithms and systems, a wideband radio signal generation and acquisition testbed, tightly synchronized in time and frequency, is needed. The development of such a testbed requires solutions to several challenges. Tight time and frequency synchronization, derived from a centrally distributed time-frequency reference signal, needs to be maintained in the hardware of the transmitter and receiver nodes, and wideband signal acquisition requires sustainable data throughput between the receiver and host PC as well as data storage at GB level. This article presents a testbed for wideband radio signal acquisition, for validation and demonstration of high accuracy ranging and positioning. It consists of multiple Ettus X310 universal software radio peripherals (USRPs) and supports high accuracy (<100 ps) time-deterministic, sustainable signal transmission and acquisition, with a bandwidth up to 320 MHz (in dual channel mode) and frequencies up to 6 GHz. Generation and processing of wideband arbitrary signal waveforms is done offline. To realize these features, radio frequency on chip (RFNoC) compatible HDL units were developed for integration in the X310 SDR platform. Wideband transmission and signal acquisition at a lower duty cycle is applied to reduce the data offloading throughput to the host’s personal computer (PC). Benchmarking of the platform was performed to demonstrate sustainable long duration dual channel acquisition. Indoor range measurements with the synchronous operation of the testbed show a decimeter-level accuracy.

A 11-years old female with growth problem and chronic renal failure was admitted for arteriovenous fistula (AVF) formation for long-term haemodialysis in the pediatric ward. During her hospital stay, continue to have a cuffed central venous catheter (CVC) as the first choice for vascular access. AVF the cubital artery vena cephalica was performed with a standard end-to-side anastomosis with a continuous running 8-0 prolene monofilament suture. The patient was discharged on the second post operative day, subsequent to a normal AVF primary patency. We recommend that vascular and pediatric Hemodialysis centers establish a strategy supporting AVF creation in small children when peritoneal dialysis is contraindicated and pre-emptive kidney transplantation is not feasible. *Correspondence to: Dragan Piljic, M.D., Ph.D., Department of Cardiovascular Surgery, University Clinical Center Tuzla, Bosnia & Herzegovina, Tel: +38735303202; E-mail: dragan.piljic@dr.com

It is very important to make the smallest possible surgical paraumbilical transperitoneal incision, the so-called minilaparotomy 8-10 cm long, which is generally sufficient to perform surgery, and significantly reduces pain after surgery, significantly accelerates wound healing, and reduces the risk of postoperative hernia to a minimum [1]. If necessary, the surgical incision can always be further expanded.

This study is concerned with modelling and analyses of a vibro-impact system consisting of a crank-slider mechanism and one oscillator attached to it, where the system can be exposed to ideal or non-ideal excitation. The impact occurs during the motion of the oscillator when it hits a base, and the excitation of the driving source is affected by this behaviour. The aim is to determine the interaction between a driving torque and the motion of the oscillator. To achieve this aim in a methodologically sound manner, both vibro-impact systems with ideal and non-ideal excitation are analysed. For these system differential equations are formed and the impact model is provided in the paper. The impact causes a strong nonlinearity in the system. The mathematical model of the vibro-impact system with ideal excitation is presented as a second order differential equation where the vibro-impact system with non-ideal excitation is given as a coupled system of nonlinear second order differential equations. Numerical simulations are carried out for the two systems and the results obtained are shown in terms of frequency response diagrams as well as in terms of time-displacement diagrams. The results found for different systems are compared mutually, and the differences between them are pointed out. Impact solutions for different regions of the excitation frequency are shown. For a specific value of the excitation frequency in the frequency response diagram where multiple solutions are found, basin of attractor diagrams are formed. Average value of the excitation frequency is used for the vibro-impact system with non-ideal excitation.

Background and Objectives: Titanium DS clips are made to secure the appendiceal stump during laparoscopic appendectomy. The assumption is that they behave like stapler clips in the body, being made from titanium. However, the construction and weight of DS clips differs from staplers. Their biocompatibility may have implications for their clinical use. Methods: One hundred and twenty rats were randomized into four experimental groups: in the first group the appendiceal stump was secured by Vicryl® ligature, in the second by linear staplers, in the third by Hem-o-lok® plastic clips, and in the fourth by DS titanium clips. Ten animals from each group were sacrificed 7, 28, and 60 days post-surgery. Histopathological data and adhesion formation were assessed. Results: On postoperative day 7, a statistically significant difference was found in the occurrence of inflammation between the Hem-o-lok® and stapler groups. The adhesion score was significantly higher in the Vycril® and Hem-o-lok® in comparison to the DS and stapler groups. On postoperative day 28, a statistically significant difference was found in the occurrence of inflammation between the Vycril® and stapler groups. The adhesion score was significantly higher in the Vycril® than in the DS and stapler groups. On postoperative day 60, there were no statistical differences between any of the groups. The adhesion score was significantly higher in the Hem-o-lok® group in comparison to the DS and stapler groups. Conclusion: Staplers and DS clips have advantages over other methods of securing the appendiceal stump, because of their high biocompatibility and lower adhesion score.

Introduction: The technique of closing the appendiceal stump using linear titanium stapler clips is being used more and more frequently in laparoscopic surgery, despite the good practice in the use of resorbable single endoloop vicryl ligatures and/or the non-resorbable plastic hem-o-lok clips. No light has been shed on potential undesirable effects on the haemathological profile of the use of titanium stapler clips. This experimental study aimed at establishing any possible undesirable effect of linear titanium stapler clips and single resorbable vicryl endoloop ligatures on the blood cells in rats following appendectomy. Methods: A total of 70 adult rats were used, divided into a control group (n = 10), and two experimental groups (n = 30 + 30). The appendices were removed from the rats in the first experimental group using titanium stapler clips and in the second experimental group the appendiceal stump using resorbable endoloop vicryl ligatures was closed. In both experimental groups three sub-groups with ten animals each were formed, from which peripheral blood from a tail vein on days 7, 28 and 60 was removed postoperatively, in order to assess the usual haematological parameters. Stained blood smears were also analysed in order to establish any poikilocytotic erythrocytes present. Results: In the first experimental group, with the titanium stapler clips, more than 25 % neutrophils were found on day 7, which is a significantly different result (p < 0.05) to the control group. In the second experimental group, there were more neutrophils than in the titanium stapler clips group, especially on days 7 and 60 and the results of these two sub-groups differ statistically significantly, p < 0.05. Hypochromia was found in the endoloop vicryl ligatures group, as well as in the titanium stapler clips sub-group on day 28, due to lower haemoglobin values which were significantly different to the control group, p < 0.05. Moderate levels of annulocytes, spherocytes and stomatocytes were found in most experimental groups. Conclusion: The results of this study favour the use of linear titanium stapler clips over resorbable single endoloop vicryl ligatures, because a less unfavourable effect was established on the blood cells of the experimental rats with their use.