35 research outputs found
Traffic efficient control of a water irrigation system
No full textWater scarcity is a persistent global issue that requires effective solutions. One increasingly popular approach to address the distribution of freshwater in different regions is the utilization of Water Irrigation Systems (WIS). Due to their vital role in ensuring people's well-being, it is crucial to design a reliable infrastructure that can maintain water levels in channels as close as possible to predefined reference points.Extensive research papers have been dedicated to discussing various aspects of WIS control, modeling, and identification. Although simulations can yield valuable insights, it is essential to validate the results in real-life systems due to certain factors that cannot be precisely estimated, such as leakages along the channels. To address this need, a scaled-down version of a WIS at TU Delft has been developed, which effectively emulates the behavior of a real water irrigation system. Through continuous refinement and design enhancements, the simulator has proven to be a valuable tool.Working with the scaled-down WIS has presented significant challenges, but a dedicated controller has been developed, yielding satisfactory results. The approach to controlling the WIS is simple yet effective, employing a decentralized controller that is applied to both the nonlinear simulator and the real setup. Remarkably, this approach successfully meets the predefined reference points, even in the face of applied disturbances to the system.Mechanical Engineerin
Adding Redundancy To Splitting Protocols for a Better Performance
No full textPayment Channel Networks have been developed to deal with the scalability issue in blockchain technologies. Using them, two parties can make multiple payments between themselves relatively fast. However, usually the channels have too small capacities, unable to handle a big payment. Allowing to split a payment into smaller payments and forwarding them through different intermediaries is a way to solve this issue, but a party only knows the capacities of the channels it is connected to. Therefore, it is possible for a payment to be sent to an intermediary which would not have sufficient funds to forward it to another node, closer to the receiver. Making redundant transactions in order to further improve the payment success ratio is a way to handle this drawback. This paper provides 3 algorithms for adding redundancy to the already existing splitting protocol. The evaluation shows that all of them improve the success ratio, but at the price of parties exchanging more messages.CSE3000 Research ProjectComputer Science and Engineerin
ORIF of Intraarticular Fractures of Distal Humerus with LCP Biplanar Plating
No full textIntroduction: Intraarticular fractures of the distal humerus are relatively rare, most frequently occurring in people in their forties. The mechanism is either a low-energy trauma, when direct hit on the elbow occurs due to a fall in the forward direction, or high-energy ones. Clinical symptoms include pain, swelling, impaired movement and disfiguration of the elbow. Standard anteroposterior and lateral radiographs of the elbow are usually sufficient for diagnosis. The AO/OTA classification is based on the fracture line location and the degree of articular involvement. These intraarticular traumas are termed as type C fracture (AO classification).Materials and Methods: During the period 2015-2017 a total of 18 of patients were admitted with distal humeral fractures. Five of them (28%) were with type C - intraarticular fractures. In all cases open reduction and internal fixation was performed. We used posterior transolecranial approach and chevron-shaped olecranon osteotomy. Once the articular surface is exposed the fracture haematoma is evacuated, and all free fragments are removed. K-wires were placed through the medial and the lateral segments to provide provisional fixation. Definitive reduction and fixation was done using biplanar plating with anatomically precontoured LCP.Results: We used Broberg and Morrey rating scale for evaluation. There were 3 patients with excellent score, 1 good, 1 fair. The mean lack of extension was 8°, mean flexion - 130°, prono-supination was reduced to 155°, with prevalence of pronation. There were no patients with early radiograph signs of arthrosis or osteonecrosis.Conclusion: The elbow joint is inherently prone to stiffness. The functional outcomes are in correlation with the achieved anatomic reduction and stable fixation, while avoiding prolonged immobilization. Using biplanar LCP gives better mechanical resistance, higher stability, and fragment compression, in comparison to uniplanar plating or non-locking plates. Thus, resulting in shorter immobilization, earlier rehabilitation and regaining full range of elbow motion
Wilson`s Diseаse in Childhood- the Hereditary Factor: a Case Report
No full textIntroduction: Wilson`s disease is a rare genetic disorder characterized by excess copper, stored in various body tissues. It usually begins by six years of age, but in most cases presents clinically in the teenage years or early twenties. The disease normally affects the liver, the brain and the corneas of the eyes. Wilson`s disease is progressive and, if left untreated, may cause hepatic or central nervous system dysfunction, and even death. Early diagnosis and treatment may prevent serious long-term disability and life-threatening complications. Treatment is aimed at reducing the amount of copper that has accumulated in the body and maintaining normal copper levels thereafter.Materials and Methods: A girl at the age of 11 was hospitalized with complaints of fatigue, abdominal pain and oedema of the lower limbs. A physical examination revealed ascites in the abdomen and enlargement of the liver. Her laboratory results showed high levels of liver enzymes and low levels of ceruloplasmin. She had been hospitalized 6 times in 4 years. Her brother, age 9, was admitted to hospital due to epigastric pain, vomiting and dark faeces. He underwent a fibrogastroscopy, which diagnosed him with chronic gastritis and enteritis. His lab results showed low hemoglobin, high levels of ASAT and ALAT, and low ceruloplasmin. The youngest sister was hospitalized because of a paresis of the right facial nerve, vomiting and epigastric pain. Her examination lead to the diagnosis of her siblings.Results: All three kids were diagnosed with Wilson`s disease, despite their various presentation. There is a 25 % chance for all three of them to inherit the defective genes from both of their parents.Conclusion: In conclusion, Wilson`s disease is a great imitator - it can be mistaken for many illnesses and the key to its diagnosis is an enzyme called ceruloplasmin
Three-Layer Reconstruction of a Full-Thickness Nasal Alar Defect after Basal-Cell Carcinoma Removal
No full textRestoring the integrity of the external nose presents a complex surgical challenge due to its three-dimensional structure and subunit divisions. The most frequent causes of nasal defects include basal or squamous cell carcinoma, animal bites and trauma. The reconstruction approach varies depending on factors such as the defect’s size, the affected subunit of the nose, the condition and quality of the surrounding tissues and the surgeon’s expertise. Commonly employed surgical techniques for nasal reconstruction include the forehead flap, nasolabial flap, Rieger flap, bilobed flap, and free autologous skin graft. We present a clinical case of a patient with a full-thickness nasal alar defect who underwent three-layer reconstruction with a combination of an inverted skin flap- for the internal lining, a conchal graft to substitute the missing alar cartilage and a forehead flap for external coverage. One of the challenges of nasal reconstruction surgery is to restore a full-thickness defect, especially the internal nasal lining. We offer a different perspective on this problem, showcasing considerable advantages, as there are limited literature data on this method
Just Unic. (Jack-Up Shoulder Prosthesis for Trauma Indications)
No full textIntroduction: Adjustable shoulder prosthesis is used for complex fractures. Indications for this system are: a three-part humeral fracture in an osteoporotic bone and four-part fractures (except where the head is no longer attached at all). In case of symptomatic avascular necrosis of the humeral head, it is possible to transform the system from an osteosynthesis device to a hemi-prosthesis by removing the staple and exchanging it with the head, placed on the same morse taper of the stem. If the indication justifies a prosthesis, then the system allows for simple prosthetic head height adjustment and optimum tuberosity repair. Materials and Methods: We present a report on 26 Bilboquet devices with an average follow-up of 25 months. The peripheral support of the humeral head is optimal in resisting varus displacement. A prospective study of 22 Bilboquet cases with an average follow-up of 34 months was conducted. Place in the therapeutic arsenal - on average for every 100 proximal humerus fractures: 20% are treated by prosthetic arthroplasty; 53% are osteosynthesised by a centromedullary nail or locking screw-plates and 27% can potentially be treated by a system with stem and humeral head staple.Results: This system allows for rapid and controlled, stable anatomical osteosynthesis of complex fractures of the upper extremity of the humerus allowing for regular tuberosity and humeral head consolidation. The stem/sleeve placed in the humeral diaphysis shaft allows for adjustable height distraction of the fracture site to restore the anatomy of the metaphyseal - cephalic position. Consolidation was obtained in all cases. There was no secondary tilt of the head nor migration or non-union of the tuberosites. Conclusion: This works aims to popularize this method in Bulgaria. Just Unic expands the possibilities of better and faster functional recovery
THE GLOBALIZING WORLD AND THE REALITY OF GLOBAL RISKS AND CATASTROPHES
No full textThis article is devoted to the possible emergence of global risks in the form of catastrophes that change the development of the Earth's space. Thus, the author motivates the necessity of measuring in advance the risks faced by nature and humanity in order to overcome these real threats and their consequences. The author analyzes the concept of "global catastrophe" and measures it as a concept and analyzes the scientific thought on this issue. It assesses the significance of the risk on the entire global space of a global catastrophe of a local or international nature. Also important is the author's approach to the issues under study and his views on the resolution of a number of conflicts and problems of global development
Diagnosing acute kidney injury ahead of time in critically ill septic patients using kinetic estimated glomerular filtration rate
No full textIntroduction: Accurate and actionable diagnosis of Acute Kidney Injury (AKI) ahead of time is important to prevent or mitigate renal insufficiency. The purpose of this study was to evaluate the performance of Kinetic estimated Glomerular Filtration Rate (KeGFR) in timely predicting AKI in critically ill septic patients. Methods: We conducted a retrospective analysis on septic ICU patients who developed AKI in AmsterdamUMCdb, the first freely available European ICU database. The reference standard for AKI was the Kidney Disease: Improving Global Outcomes (KDIGO) classification based on serum creatinine and urine output (UO). Prediction of AKI was based on stages defined by KeGFR and UO. Classifications were compared by length of ICU stay (LOS), need for renal replacement therapy and 28-day mortality. Predictive performance and time between prediction and diagnosis were calculated. Results: Of 2492 patients in the cohort, 1560 (62.0%) were diagnosed with AKI by KDIGO and 1706 (68.5%) by KeGFR criteria. Disease stages had agreement of kappa = 0.77, with KeGFR sensitivity 93.2%, specificity 73.0% and accuracy 85.7%. Median time to recognition of AKI Stage 1 was 13.2 h faster for KeGFR, and 7.5 h and 5.0 h for Stages 2 and 3. Outcomes revealed a slight difference in LOS and 28-day mortality for Stage 1. Conclusions: Predictive performance of KeGFR combined with UO criteria for diagnosing AKI is excellent. Compared to KDIGO, deterioration of renal function was identified earlier, most prominently for lower stages of AKI. This may shift the actionable window for preventing and mitigating renal insufficiency
Numerical modelling of an experimental energy pile
No full textGeothermal energy is a way of reducing the cost of energy. Deep geothermal energy systems extract heat from very deep soil layers where the temperatures are very high. Shallow geothermal energy systems are about 150 metres deep and they are used to store heat in the soil, to extract it later and use it for space heating. These shallow geothermal systems are generally embedded in a borehole, but they can also be cast into structures, which are called thermo-active foundations. An example of such a foundation is the energy pile, a foundation pile with a heat exchanger embedded in it, connected to a heat pump. There is no need to drill an extra hole in the ground, but the downside is that it is not well known how the bearing capacity of the pile is affected by the heating/cooling cycles. An energy pile experiment is planned to investigate the thermo-mechanical behaviours of the pile and the goal of this thesis is a numerical investigation of the pile. It serves as an estimate of the pile and soil behaviour prior to installation and the results will be used to confidently design the experiment. The model was built with DIANA FEA software, that is capable of coupling thermo-mechanical behaviour. Firstly an experiment in London clay was recreated in order to verify and validate the model and modelling approach. The experiment in Delft was modelled using site investigation that was done at the location where it will be built. Along with old Cone Penetration Test (CPT) data the subsurface was mapped and soil parameters used in the material model were chosen. The thermal cycle that was imposed on the pile was chosen on the basis of preliminary modelling done at different temperature increments. The temperatures were chosen such that the pile was affected to a significant degree of its capacity. It was cooled for three weeks to 0 °C and then heated to 24 °C for three weeks, this was repeated for 6 years. The research focussed on finding which thermo-mechanical effects can be expected and what the scale of those effects could be. The effect directly linked to an increase in temperature is thermal strain. Materials tend to expand and contract with the temperature at different rates and so do the pile and the soil. The gradient of the heat flow is also an important factor as the pile is subjected to the temperature before the soil is. The pile will expand first and this will be resisted by the soil, the strain that is resisted by the soil is called the restrained strain and that is responsible for the change in stress in the pile. A pile that is heated will have more stress than with just a mechanical load and a pile that is cooled will see a reduction in stress. The pile will expand vertically around a null-point somewhere along the pile, this is the point that does not move. In principle, an unrestrained pile will have a null-point in the centre of the pile, but because some soil layers resist the pile movement more than others the null-point is closer to the stronger layers. In the Delft experiment model the null-point was halfway down the pile at first, but as the amount of cycles progressed it moved down. This is due to a decrease in resistance from the weaker layers and an increase in resistance in the strong sand layer on which the pile is based. The amount of stress that is generated is also less in these later cycles as the resistance of the soil became less. With that reduced resistance an increase in settlement is also seen. This can lead to differential settlements of structures that are built on such a pile, possibly damaging them. The results of the modelling are used to give an advice on the experiment details, such as geometry, thermal cycle and pile layout. An advice to the layout of the sensors is included as well as a prediction of the results
2D representation of RNA pseudoknots () class IIa—the actual sequence is of () class IIb—the sequence is of an aphid
No full text<p><b>Copyright information:</b></p><p>Taken from "Ribosomal frameshifting in decoding antizyme mRNAs from yeast and protists to humans: close to 300 cases reveal remarkable diversity despite underlying conservation"</p><p></p><p>Nucleic Acids Research 2007;35(6):1842-1858.</p><p>Published online 1 Mar 2007</p><p>PMCID:PMC1874602.</p><p>© 2007 The Author(s)</p> The frameshift site is indicated with orange letters. Black arrowheads represent substitutions deduced from phylogenetic comparison to orthologous genes. Non-compensatory changes in the stems are shown in black letters; compensatory changes are shown in blue letters
