Procena dinamičke nestabilnosti kolena kod povrede zadnje ukrštene veze pomoću trodimenzionalnog OptiTrack sistema

Uvod: Koleno je jedinstven zglob u ljudskom telu po tome što je najveći zglob, najsloženije anatomske građe sa vrlo kompleksnom biomehanikom. Pokreti u zglobu su jako složeni i sastoje se u osnovi iz translacije i rotacije, a mogući su u sve tri ravni prostora. Određeni su kako geometrijom zglobnih površina tako i mekotkivnim omotačem zgloba. Primenom novih tehničkih dostignuća, pre svega tehnika snimanja i praćenja pokreta tela i zglobova, pruža nam se mogućnost da proučavamo biomehaniku koleno na jedan nov način. Metodologija: Cilj ove studije je da se korišćenjem OptiTrack sistema, koji se sastoji od specijalizovanih infracrvenih kamera visoke preciznosti i klasifikacionih algoritama, izmere mikro pokreti u kolenu, koji nastaju kao posledica nedostatka zadnjeg ukrštenog ligamenta. Odabrani su pacijenti koji imaju povredu zadnje ukrštene veze jednog kolena. Upoređuje se biomehanika povređenog kolena, sa zdravim zglobom suprotne strane i sa istim kolenom nakon hirurške intervencije. Rezultati: U ovoj seriji od 16 pacijenata bilo je 13 muškaraca i 3 žene, prosečne starosti 28.6 godina. Upoređujući obrasce pokreta dobijene OptiTrack sistemom kod zdravog i povređenog zgloba jasno je da je šema pokreta poremećena. Izražena je zadnja nestabilnost prikazana kroz zadnje pomeranje tibije kao i povećana spoljašnja rotacija tibije u fazi oslonca kod nestabilnog zgloba. Koristeći Vilkoksonov test, dokazano je da postoji statistički značajna razlika između zdravog i bolesnog kolena, u pogledu anteriorno-posteriorne translacije i interno-eksterne rotacije. Nakon hirurške intervencije rezultati merenja su pokazali da je biomehanika zgloba vraćena u fiziološke granice. Zaključak: Rezultati ove studije su jasno pokazali dinamičku nestabilnost koja nastaje u kolenu sa oštećenim zadnjim ukrštenim ligamentom, a koja se može objektivno izmeriti OptiTrack sistemom. Operativnim lečenjem ove povrede, pokreti kolena se vraćaju u normalne granice kao kod zdravog zgloba.Introduction: The knee is a unique joint in the human body because it is the largest joint, with the most complex anatomy and very complex biomechanics. The movements in the knee are very complicated and consist essentially of translation and rotation and are possible in all three levels of space. They are determined by the geometry of the articular surfaces and by the soft tissue of the joint. By applying new technical achievements, primarily the technique of recording and monitoring movements of the body and joints, we are able to study the biomechanics of the knee in a new way. Methodology: The aim of this study is to measure the micro-movements in the knee, which result from the lack of the posterior cruciate ligament using the OptiTrack system, which consists of specialized high precision infrared cameras and classification algorithms. Patients who have a rupture of posterior cruciate ligament of one knee were selected. The function of тhe biomechanics of an injured knee is compared with a healthy joint on the opposite side and with the same knee after surgery. Results: In this 16-patient series, there were 13 males and 3 females, with an average age of 28.6 years. Comparing patterns of motion obtained with the OptiTrack system in a healthy and injured knee, it is clear that the scheme of the movement is disturbed. The posterior instability was expressed through the posterior displacement of the tibia in the support phase of walking, as well as the increased external rotation of the tibia in the support phase in the unstable joint. Using the Wilcoxon signed-rank test, it has been shown that there is a statistically significant difference between healthy and diseased knee, in terms of anterior-posterior translation and internal-external rotation. After surgical intervention, the results of the measurement showed that the biomechanics of the joints were in normal physiological limits. Conclusion: The results of this study clearly demonstrated the dynamic instability that occurs in the knee with posterior cruciate ligament rupture that can be objectively measured by the OptiTrack system. Operative treatment of this knee injury returns movements of the joint in the normal limits as in a healthy one

Upotreba recikliranog PET-a ((Poli) etilen-tereftalat) za vezivanje armature

Recycling has an important role in modern production and in environment preservation. Introduction of recycled PET ((Poly) Ethylene-terephthalate) as straps for reinforcement bars in concrete construction elements can help these important issues. By using an experimental method it is shown that PET straps made with minimal investment, on site and with manual production can replace ‘annealed’ wire as element for connection of reinforcement bars. An overview of some regulation and procedures is presented and used for eligibility assessment of the proposed straps made of recycled material. Also an overview of commonly used connections is given so it can be compared with the proposed ones.Reciklaža zauzima sve važniju ulogu u modernoj proizvodnji i očuvanju životne sredine. Uvođenje recikliranog PET-a ((Poli) Etilen-tereftalat) kao veze za armaturne šipke u betonskim konstruktivnim elementima može doprineti ovim važnim ciljevima. Korišćenjem eksperimentalne metode pokazano je da ovakve veze načinjene od recikliranog PET-a, uz minimalne investicije, napravljene na licu mesta i ručnom izradom mogu zameniti “paljenu”žicu kao element kojim se ostvaruje konekcija između armaturnih šipki. Dat je i kratak pregled nekih propisa i procedura koje su korišćene za procenu predloženih veza od navedenog recikliranog materijala. Takođe je dat i pregled najčešće korićenih veza kako bi moglo da se napravi poređenje sa predloženim rešenjem

Investigation of the Collapse of a Building in the Final Stage of Its Construction

In 2009, the Municipal Court of the City of Cajetina, Republic of Serbia, issued an order to a Commission of court-appointed experts (Commission) to perform an analysis of the collapse of a building in the final stage of its construction. The Commission was appointed by the Faculty of Architecture, University of Belgrade. The study reveals the steps taken in the process of determining the cause of collapse and the problems that have led to it, the conclusions and findings. Poor design and bad execution led to the collapse of the building. The causes of collapse were structural defects in calculations and rebar detailing, disregard of the procedures related to technical supervision and the procedure of obtaining a building permit, violation of building codes and good practice. The cause was determined using the following methods: analysis of documentation, analysis of regulations and legislation, in situ observations, interviews with participants on the process, and structural analysis through three dimensional modelling. The study also shows that safety factors in the built construction elements were low and inadequate. This work summarizes the principles, conclusions and findings of forensic investigation

Diagnosis and surgical treatment of the posterior knee instability

Background/Aim. Posterior cruciate ligament is the primary stabilizer of the posterior tibia translation and secondary stabilizer of external tibial rotation as well as varus, valgus knee angulation. It is the strongest ligament in the knee that hurts the rarest. The aim of this study was to show the indications for surgery, present the surgical technique and give results of surgical treatment of posterior knee instability. Methods. The study icluded 12 patients who were tretaed surgically for posterior knee instabilility at the Institute for Orthopaedic Surgery “Banjica“, Belgrade, in the period from 1st January 2010 to 1st January 2014. All of them had arthroscopically assisted anatomic reconstruction of posterior crucuate ligament done with 4-strand hamstring tendon graft. Postoperative follow-up lasted approximately 42 months and Lysholm values and International Knee Documentation Committee (IKDC) score were compared as well as the clinical status. Results. All treated patients had Grade III of posterior instability. Combined injuries of the posterolateral corner and anterior cruciat ligament (75%) were very frequent. Preoperative mean value of Lysholm score was 45.92 and postoperative 85.92 what was statistically significant improvement, the same as subjective IKDC score whose mean value was 38.58 preoperatively and 89.75 after the surgery and rehabilitation. Clinical examination showed better posterior knee stability although in 50% of patients certain level of instability remains. Conclusion. Arthroscopic reconstruction with 4-strand hamstring tendon gives satisfactory result with posterior cruciate ligament reconstruction. The result of subjective feeling of patient is much better then objective clinical examination. Although surgical procedure is technically demanding, with physically active patients having grade III of posterior instability it provides better result than non-surgical treatment

ANALYTICAL INDICATORS OF PLUM FRUIT SENSORY CHARACTERISTIC CHANGES AFTER SEVEN-DAY STORAGE AT ROOM TEMPERATURE

Consumer acceptance of plum is based, primarily, on the corresponding sensorycharacteristics of the fruits: appearance, colour, firmness, taste and aroma. If notconsumed immediately after harvesting, the aforementioned characteristics of plumwill change. Still, those changes are less expressed when fruits are kept in coldstorage, at low temperatures. However, during the transport and storage of plum atroom temperature, which is often the case in local market plum sale, intensechanges of certain characteristics of the fruit happens as well as a significantshortening of shelf life. The most expressive is firmness change where fruitsbecome completely soft after seven days. Appearance and colour of the fruit areless susceptible to change. Since plum taste and odour depend on sugar and acidcontent, i.e., sugar-acid ratio and the content of certain volatile aromaticcomponents, changes of their contents have been examined in some importantplum cultivars in Serbia after seven-day storage at the temperature 20±1 °C. Sugaracidratio that determines sweetness, i.e., fruit acidity, has not significantly changedduring thе storage period. Among 10 examined aromatic components, the mostsignificant changes have been observed in 2-E-hexenal, which gives a distinctivegreen note aroma and nonanal, characteristic plum-like scent. During the seven-daystorage of picked plums, the content of 2-E-hexenal decreased while the content ofnonanal increased

Effect of surgical drill guide and irrigans temperature on thermal bone changes during drilling implant sites - thermographic analysis on bovine ribs

Background/Aim. During drilling implant sites, mechanical energy is converted into thermal one resulting in transient rise in temperature of surrounding bone. The temperature of 47°C exeeding one minute impairs osseointegration, compromises mechanical properties of the local bone and could cause early implant failure. This in vitro study aimed to assess the effect of surgical drill guide and temperature of irrigans on thermal changes of the local bone during drilling implant sites, and to test the influence of irrigans temperature on the temperature of surgical drill guide. Methods. A total of 48 specimens obtained from bovine ribs were randomly allocated to four experimental conditions according to the 2 x 2 factorial design: drill guide (with or without) and saline (at 25°C or 5°C). Real-time infrared thermography was used as a method for temperature measurement. The primary outcome was bone temperature change during drilling implant sites measured at 3 osteotomy depths, whereas the second one was change in the temperature of the drill guide. Data were analyzed by Brunner and Langer nonparametric analysis and Wilcoxon test. Results. The effect of drill guide on the changes of bone temperature was significant at the entrance of osteotomy, whereas the effect of saline temperature was significant at all osteotomy levels (p < 0.001). No significant interaction was found (p > 0.05). Guided surgery and irrigation with saline at 25°C were associated with the highest bone temperature increase. Increase in drill guide temperature was significantly higher when saline at 25°C was used (p < 0.001). Conclusion. Guided implant site preparation generates higher temperature of the local bone than conventional drilling, not exceeding the threshold for thermal bone necrosis. Although saline at room temperature provides sufficient heat control during drilling, cooled saline is more effective regardless the use of surgical drill guide

Quality of life in patients with chronic liver disease

Background/Aim. Quality of life is impaired in patients with the chronic liver disease (CLD). Patients with this disease have numerous disabling problems which lead to a reduced health related quality of life (HRQoL). The aim of our study was to evaluate the predictive value of selected socio-demographic and clinical characteristics on HRQoL in Serbian cohort of patients with the CLD. Methods. Over a period of one year, we performed a study which included patients with the CLD. We used Short Form Health Survay-36 (SF-36) for assessment of HRQoL. The assessment of depression and anxiety was made by using Hamilton scale of depression and anxiety, while the assessment of fatigue was performed by Fatigue severity scale. Results. The study included 103 patients with the CLD. The average values of the overall SF-36 scores were 52.6 ± 20.4, while the mean score of the composite scores were 53.5 ± 19.6 for the Mental component summary and 49.8 ± 21.3 for the Physical component summary. Some domains of HRQoL were significantly affected by following factors: gender, age, employment status, alcohol consumption, depression, anxiety and fatigue. Predictors of physical components of HRQoL were employment, depression and fatigue, and predictors of mental components were depression and fatigue. Conclusion. The tested socio-demographic, clinical and behavioral factors have an impact on the HRQoL in patients with the CLD. The most important predictors of HRQoL are behavioral factors suggesting the need for an adequate therapeutic action in order to improve the HRQoL in these patients