ANATOMIC AND PHYSIOLOGICAL FEATURES OF DISTAL LOWER LEG AND THEIR INFLUENCE ON THE PROCESS OF OSTEOGENESIS

Osteogenesis is the process of bone tissue forming, i.e. bone or callus regeneration. This process is influenced by many factors, and the degree of bone fragments’ stability and vascularization in the fracture area are the basic local factors which determine the nature of reparative process. Regenerative process of all bone structures increases with increasing of blood supply.The distal lower leg has its specific biomechanical features, and plays an important role in the transfer of body weight to foot. The distal part of tibia has a small diameter, which as a consequence has reduced diameter in medullar cave. Through this anatomic feature, the medullar network in the lower tibia part is also reduced.As for anatomic aspect, vascularization in the lower end of tibia is poor. It primarily depends on periosteal vascularization, because medullar vascularization is reduced. Fasciae, tendons and skin cover the lower part of the leg, and there is no muscle mass. These tissues have poor vascular network and that is why the extraosseous blood circulation in tibia is poor, and does not participate in the osteogenesis process. For these reasons, distal lower leg represents a predelection site for delayed osteogenesis and pseudoarthrosys development.Osteosynthesis causes secondary damage to bone and soft tissue circulation. The screw plate damages the periosteal circulation – in the lower part of tibia it is the main source of vascularization, and for this reason, this method of osteosynthesis should not be applied. The external fixator has a sparing role regarding vascularization, and that is the reason why this method is recommended for fracture stabilization at the level of distal lower leg

An Atomistic Modelling Framework for Valence Change Memory Cells

We present a framework dedicated to modelling the resistive switching operation of Valence Change Memory (VCM) cells. The method combines an atomistic description of the device structure, a Kinetic Monte Carlo (KMC) model for the creation and diffusion of oxygen vacancies in the central oxide under an external field, and an ab-initio quantum transport method to calculate electrical current and conductance. As such, it reproduces a realistically stochastic device operation and its impact on the resulting conductance. We demonstrate this framework by simulating a switching cycle for a TiN/HfO$_2$/TiN VCM cell, and see a clear current hysteresis between high/low resistance states, with a conductance ratio of one order of magnitude. Additionally, we observe that the changes in conductance originate from the creation and recombination of vacancies near the active electrode, effectively modulating a tunnelling gap for the current. This framework can be used to further investigate the mechanisms behind resistive switching at an atomistic scale and optimize VCM material stacks and geometries.Comment: 4 pages, 5 figures. Submitted to Solid-State Electronics Special Issue: LETTERS from the International Conference on Simulation of Semiconductor Processes and Devices 202

Uloga hirurških procedura u prevenciji i lečenju osteoartroza kuka nastalih morfološkim promenama vrata butne kosti

Introduction: Hip osteoarthrosis is a common disease, it can be primary or secondary. Secondary hip arthrosis can often be the consequence of morphological changes on the femoral neck bone, and it is the cause of femoroacetabular impingement. The pathophysiology of impingement is characterized by premature contact of femoral neck and head joint with frontal or upper frontal edge of acetabulum. Aim of the paper: The analysis of the effect of femoral morphological changes, by the type of bone bump - CAM deformity, to the development of hip joint osteoarthrosis and the justification of surgical treatment of the deformity as a means of prevention. On experimental animals surgically create a morphological change on the femoral neck, CAM deformity type, and determine the form and the degree of the hip joint osteoarthrosis development. Analyze the test subjects who have undergone hip aloarthroplastics due to osteoarthrosis caused by CAM deformity, with heightened focus on the femoral head bone position and size, form and position of the bone bump. Method: This research includes two groups of human test subjects and a group of experimental animals. In one group of test subjects we have monitored clinical and radiological signs caused by CAM deformity, pre and post-operatively. The other group of test subjects includes patients who have been implanted total cementless hip endoprosthesis, due to the secondary hip osteoarthrosis caused by CAM deformity that had not been treated surgically. We have induced iatrogenically a CAM deformity on experimental animals, by placing a metal screw in the femoral head and neck joint of a hare, and then we have histologically monitored the development of secundary arthrosis on the hip – we have monitored the time of its origin and the degree of damage. Results: They have been grouped to demographic, clinical, radiological and histological results. Demographic results deal with the development of femoroacetabular impingement in young people and the need to detect clinically and radiologically morphological deformities of femoral head and neck early and treat them surgically. Postoperative clinical and radiological parameters in this group of test subjects suggest an absolute need and justify surgical treatment. Non-treated morphological deformities lead to an early osteoarthrosis of the hip, which can be solved with an implantation of hip endoprosthesis, ie. the replacement of natural hip joint with an artificial one. Significant differences between preoperative and postoperative values of the tested parameters have been found, which suggests a need for an early detection and surgical treatment of CAM deformities. Experimental results confirm the influence of CAM deformities to cartilage and labrum of the hip joint regarding the development of osteoarthrosis. Conclusion: Through experimental work and collected histological results, we have confirmed the influence of iatrogenic CAM deformity on femoral neck, to the development of Marko D. Mladenović: Uloga hirurških procedura u prevenciji i lečenju osteoartroza kuka nastalih morfološkim promenama vrata butne kosti secondary hip osteoarthrosis. According to the stage of development, it is more present in hares which have long been exposed to the influence of this type of morphological change on the femoral neck. Femoroacetabular impingement needs to be detected early, clinically and radiologically identified, and surgically treated as soon as possible. The results of operative treatment and hip joint durability depend on the degree of cartilage damage at the moment of the surgical treatment. Hip joint osteoarthrosis caused by CAM deformity develops in younger persons after 45 – 55 years of life, and the only solution is the implementation of cementless hip endoprosthesis. It needs to be a prosthesis from the group of short stemmed prostheses, in order to spare femoral metaphysis and save the diaphysis for secondary surgical intervention, ie. reintervention. Considering artificial hip joint implementation, clinical and radiological preoperative planning is necessary

Kombinatorne biblioteke odabranih prirodnih i sintetskih biološki aktivnih estara

Herein, a successful identification and a means of arriving at (milli)gram quantities of the selected natural esters was achieved through the application of a synthetic combinatorial approach (three libraries with 171 constituents in total, among them 121 new compounds). As a result, new secondary metabolites from Achillea falcata L. ((1R*,3S*,5R*)-sabinyl formate and tiglate), Achillea ageratifolia (Sm.) Boiss. subsp. serbica (Nyman) Heimerl ((1R*,3S*,5R*)-sabinyl formate, tiglate, nonanoate and decanoate), Scandix balansae Reut. ex Boiss. (octadecyl valerate), Scandix pecten-veneris L. (esters of isobutanoic acid and n-C15, C17, C21 and C23 alkanols, as well as esters of isovaleric acid and n-C13, C15 and C17 alkanols) and Anthemis segetalis Ten. (eugenyl angelate, 2-methylbutanoate and 3- methylbutanoate) essential-oil samples wеre identified. Also, the combinatorial approach was successful used for a systematical comparison of chemical/biological properties of ferrocene-containing esters and their corresponding phenyl analogs (a library of eighteen (13 new) 2-substituted methyl acetoacetates). The structures of the synthesized esters were spectrally characterized by MS, NMR (1D- and 2D-NMR, as well as, an NMR methodology that employ lanthanide-induced shifts), FTIR and UV-Vis analyses, and in the case of ferrocene-containing compounds by electrochemical (cyclic voltammetry) and X-ray analyse(s). Several esters were shown to be toxic to A. salina, possessed cytotoxic (to two cell lines), AChE inhibitory, antinociceptive and antimicrobial activities. Antinociceptive activity of (1R*,3S*,5R*)-sabinol was two times higher than that of morphine, and the antifungal activity of 2- acetyl-2-(ferrocenylmethyl)-4-methyl-4-pentenoate was comparable to that of nystatin against Candida albicans

A scalable dynamic parking allocation framework

International audienceCities suffer from high traffic c ongestion of which one of the main causes is the unorganized pursuit for available parking. Apart from traffic congestion, the blind search for a parking slot causes financial and environmental losses. We consider a general parking allocation scenario in which the GPS data of a set of vehicles, such as the current locations and destinations of the vehicles, are available to a central agency which will guide the vehicles toward a designated parking lot, instead of the entered destination. In its natural form, the parking allocation problem is dynamic, i.e., its input is continuously updated. Therefore, standard static allocation and assignment rules do not apply in this case. In this paper, we propose a framework capable of tackling these real-time updates. From a methodological point of view, solving the dynamic version of the parking allocation problem represents a quantum leap compared with solving the static version. We achieve this goal by solving a sequence of 0-1 programming models over the planning horizon, and we develop several parking policies. The proposed policies are empirically compared on real data gathered from three European cities: Belgrade, Luxembourg, and Lyon. The results show that our framework is scalable and can improve the quality of the allocation, in particular when parking capacities are low

The parking allocation problem for connected vehicles

In this paper, we propose a parking allocation model that takes into account the basic constraints and objectives of a problem where parking lots are assigned to vehicles. We assume vehicles are connected and can exchange information with a central intelligence. Vehicle arrival times can be provided by a GPS device, and the estimated number of available parking slots, at each future time moment and for each parking lot is used as an input. Our initial model is static and may be viewed as a variant of the generalized assignment problem. However, the model can be rerun, and the algorithm can handle dynamic changes by frequently solving the static model, each time producing an updated solution. In practice this approach is feasible only if reliable quality solutions of the static model are obtained within a few seconds since the GPS can continuously provide new input regarding the vehicle’s positioning and its destinations. We propose a 0–1 programming model to compute exact solutions, together with a variable neighborhood search-based heuristic to obtain approximate solutions for larger instances. Computational results on randomly generated instances are provided to evaluate the performance of the proposed approaches.</p

The parking allocation problem for connected vehicles

International audienceIn this paper, we propose a parking allocation model that takes into account the basic constraints and objectives of a problem where parking lots are assigned to vehicles. We assume vehicles are connected and can exchange information with a central intelligence. Vehicle arrival times can be provided by a GPS device, and the estimated number of available parking slots, at each future time moment and for each parking lot is used as an input. Our initial model is static and may be viewed as a variant of the generalized assignment problem. However, the model can be rerun, and the algorithm can handle dynamic changes by frequently solving the static model, each time producing an updated solution. In practice this approach is feasible only if reliable quality solutions of the static model are obtained within a few seconds since the GPS can continuously provide new input regarding the vehicle’s positioning and its destinations. We propose a 0–1 programming model to compute exact solutions, together with a variable neighborhood search-based heuristic to obtain approximate solutions for larger instances. Computational results on randomly generated instances are provided to evaluate the performance of the proposed approaches

Krutost asfaltnih mešavina sa dodatkom struganog asfalta

Reclaimed Asphalt Pavement (RAP) is largely used in developed countries in the hot-asphalt mixtures. One of the most important characteristics of asphalt mixtures is their stiffness which depends on temperature and loading frequency. Master curves define the change of stiffness with frequency for the specified temperature and they are used for comparison of asphalt mixtures and for pavement design. The paper presents the testing of three asphalt mixtures: a mixture without RAP and with 15% and 30% of RAP. The indirect tensile test was performed at temperatures of 0 °C to 30 °C and the load duration was 200 and 300 ms to obtain stiffness moduli. The results indicate that the addition of 30% RAP significantly increases the stiffness of the mixture, while the addition of 15% RAP results in relatively small increase of stiffness, which means that the use of up to 15% RAP has no significant effect on the characteristics of the mixture. .Strugani asfaltni materijal (RAP - Reclaimed Asphalt Pavement) se u razvijenim zemljama u značajnoj meri koristi pri proizvodnji asfaltnih mešavina po vrućem postupku.Jedna od najznačajnijih karakteristika asfaltnih mešavina je njihova krutost, koja zavisi od temperature i frekvencije opterećenja. Master krive definišu promenu modula krutosti sa frekvencijom opterećenja na određenoj temperaturi i koriste se za upoređenje asfaltnih mešavina i za dimenzionisanje kolovoznih konstrukcija. U okviru rada su ispitane tri mešavine: mešavina bez struganog materijala, sa 15% i sa 30% struganog materijala. Ispitivanje je vršeno pri temperaturama od 0 oC do 30 oC i pri trajanju opterećenja od 200 i 300 ms korišćenjem opita indirektnog zatezanja. Dobijeni rezultati ukazuju da dodatak struganog materijala od 30 % u značajnoj meri povećava krutost mešavine, dok dodatak od 15 % relativno malo utiče na povećanje krutosti što znači da primena do 15 % struganog materijala nema značajnog efekta na promene karakteristika mešavine

PHENETHYL ANGELATE – A NEW ESTER FROM IMMORTELLE ESSENTIAL OIL?

Esters of angelic, senecioic and tiglic acids with various saturated/unsaturated/aromatic alcohols contribute to the aroma of many essential oils. However, mass spectrometry with electron-impact ionization sometimes fails to distinguish these regio-/geometric isomers and this was the case with the minor constituent of Helichrysum italicum (immortelle) essential oil that was tentatively identified as the ester of 2-phenyl-1-ethanol with one of the mentioned acids. Our efforts to identify this phenethyl ester were also hampered by the inconsistency or by the lack of appropriate RI data in the literature. Therefore, we prepared and fully spectrally characterized (1D- and 2D-NMR, IR, MS) synthetic samples of all three isomeric esters. Subsequent GC analyses of immortelle oil samples with spiked synthetic phenethyl esters unambiguously confirmed that the compound in question was phenethyl angelate. This rare plant secondary metabolite has been previously reported only twice as a constituent of samples of natural origin. However, the outcomes of our study strongly imply that this molecule was misidentified in these earlier studies with the corresponding senecioate/tiglate. Thus, the existing libraries of RI/MS data for tiglates and angelates have to be upgraded with appropriate data for senecioates to avoid these kinds of errors in the future

Inovativni materijali I tehnologije za izgradnju puteva

У раду је дат приказ неколико иновативних технолошких решења чија се примена може очекивати у будућности у контексту све оштријих захтева у погледу саобраћајног оптерећења и услова околине, имајући у виду специфичан утицај климатских промена на путну инфраструктуру, а поштујући принципе одрживог развоја. Посебно су прказане могућности модификације битумена и асфалтних мешавина са отпадном гумом и пластиком, производња и уграђивање асфалтних мешавина по топлом поступку, као и поступци за само-зацељивање асфалтних слојева. Применом ових поступака омогућава се побољшање карактеристика асфалтних слојева и њиховог експлоатационог века, смањење трошкова одржавања, и смањење негативног утицаја на околину проузрокованог радовима на изградњи и одржавању путева.The paper presents several innovative technologies whose implementation can be expected in the future in the context of increasingly demanding requirements regarding traffic loading and environmental conditions, bearing in mind the specific impact of climate change on road infrastructure, while respecting the principles of sustainable development. In particular, the possibilities of modifying bitumen and asphalt mixtures with waste rubber and plastic, production and compaction of warm asphalt mixtures, as well as procedures for self-healing of asphalt layers are shown. By applying these procedures, it is possible to improve the characteristics of asphalt layers and their operational life, reduce maintenance costs, and reduce the negative impact on the environment caused by road construction and maintenance works