Search

Background/Aim. There is limited data on the frequency of intracranial hemorrhage (ICrH) in the first wave [beta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] and second wave (delta variant of SARS-CoV-2) coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to analyze the appearance of ICrH in COVID-19 patients (CP). Methods. Among 505 CP treated at the Special Hospital for Cerebrovascular Diseases “Sveti Sava” intermittently during the 2020–2021 period, ICrH was diagnosed in 76 (15.1%) patients. The available information from the medical records regarding clinical, demographic, as well as radiological data (multislice computed tomography examination of the endocranium) was collected and analyzed. Results. In the first wave, out of 308 CP, 63 (20.5%) were diagnosed with ICrH. In the second wave, out of 1 97 CP, ICrH was diagnosed in 13 (6.6%) patients, which was a statistically significant difference (p < 0.002). There was no statistically significant difference for the presence of hyper-tension (p = 0.271), diabetes mellitus (p = 0.558), and chronic obstructive pulmonary disease (p = 0.794) among CP with ICrH comparing the two waves of the pandemic. However, a statistically significant difference was proven in the frequency of patients with atrial fibrillation and anticoagulant drug therapy (p = 0.021 each). There was no statistically significant difference in the frequency of patients with fever ( p = 0.637), fatigue (p = 0.587), hemiparesis (p = 0.831), respiratory symptoms (p = 0.289), and loss of consciousness (p = 0.247). D-dimer values in the second pandemic wave were statistically significantly lower (p = 0.003). The combination of ischemic stroke and ICrH was six times more common in the second wave (p = 0.003). However, cerebral parenchymal hemorrhage was two times less frequent (p = 0.001) in the second wave but with statistically higher frequencies of multifocal (23.1%) and diffuse type (36.4%) of ICrH (p = 0.007). Combined hemorrhages, as well as subarachnoid and subdural sub-types, were more common in the second wave (23.1% each). Fatal outcomes occurred in 38.1% of patients in the first wave compared to 69.2% in the second wave (p = 0.039). Conclusion. In the first pandemic wave of COVID-19, ICrH in CP was significantly more frequent and D-dimer was singled out in laboratory analyses, the values of which were statistically significantly higher in comparison with second wave. In the second wave of COVID-19, parenchymal ICrH was less frequent and multifocal and diffuse ICrH were more common in CP with ICrH. The mortality rate was very high in the second wave.

Special-purpose river port sediment was investigated for its potential use as a road construction material. Sediment samples were extracted from three locations in three small river ports, and detailed laboratory research was conducted to determine its basic mechanical properties and characteristics that can potentially have an adverse influence in a roadside environment. The results of the research conducted indicate that there is a need for systematic monitoring of the quality and quantity of sediment in special-purpose river ports of the Danube River Basin to maintain its mobility and prevent flooding. The basic engineering characteristics (Proctor elements, Atterberg limits, California bearing ratio, and unconfined compressive strength) determined represent the good potential of the sediment samples tested herein for use in road construction. In addition, the chemical characteristics tested indicate the need for detailed analyses of the potential environmental risk before application in civil engineering structures

For the air-conditioning of the IKEA sales complex in Belgrade, the exploitation of groundwater, as a subgeothermal resource, was carried out, using a heat pump. The groundwater from a karst aquifer is abstracted by the three drilled wells, the depths of which are 87-103m. Based on the results of the 1-year trial exploitation, in the period August 2017-July 2018, balance reserve of the groundwater is 10.8 l/s, with temperatures in the range 22.0-22.9 0C, which gives the nominal available thermal power of the system of 774 kWt. The applied air-conditioning solution can be assessed as energy efficient, due to the efficiency of the "water-water" heat pump system, as well as to an environmental contribution, by the substitution of fossil fuels. Preliminary economic analysis shows that total financial investments in the system, compared with the "conventional" alternative solution, are paid after less than six years.

nema

Introduction. Positron emission tomography (PET) with computed tomography (CT) using fluorine- 18-labeled fluorodeoxyglucose (18F-FDG PET/CT) is a hybrid diagnostic method based on the cell’s glucose uptake detection, which correlates with the degree of disease activity. While other diagnostic procedures fail to evaluate functional tissue, 18F-FDG PET/CT can be helpful in discovering active disease in patients with vascular graft infection. Methods. This cohort retrospective study included 22 patients (17 male, five female; aged 61.7 ± 16.1) with suspected vascular graft infection. Blood analyses and CT were performed in all patients. Degree of glucose uptake was evaluated visually and semiquantitatively using maximal standardized uptake value (SUVmax). Findings were considered positive if focal fluoro-deoxyglucose (FDG) accumulation was greater in vascular graft projection than other parts of the blood vessel and liver. Results. The sighs of active disease were found in 19 patients (86%) (16 male, three female) at the level of implanted vascular grafts: six aortobifemoral (27%), four aortoiliac (18.2%), four of abdominal aorta (18.2%), two of thoracic aorta (9.1%), two femoral (9.1%), one femoropopliteal (4.5%) (SUVmax 7.9 + 2.4). Two patients were considered true and one false negative- due to antibiotic usage, which reduces FDG uptake. PET/CT helped in treatment alteration of 12 patients, seven (31.8%) started new medicament therapy, five (22.7%) had a surgical graft replacement. Overall sensitivity of this method is 95%, specificity 100%, positive predictive value 100%, negative predictive value 66.6%, accuracy 95.4%. Conclusion. 18F-FDG PET/CT is a useful diagnostic method in detection of active vascular graft infection with high diagnostic accuracy, which is important in avoiding unnecessary surgery and appropriate therapy planning.

Background/Aim. Disruption of cerebral venous blood drainage leads to cerebral venous congestion, an increase in intracranial pressure and decrease of the cerebral perfusion pressure. The exact role of the cerebral venous circulation in acute stroke is not yet known. The main blood drainage from the brain and the superficial parts of the face and neck is drained by a paired internal jugular vein (IJV). Congenital anomalies of IJV may disrupt the blood collection from the brain, which leads to congestion of the cerebral venous circulation. The aim of our study was to determine the association between the hypoplastic ipsilateral IJV and clinical outcome of patients with acute ischemic anterior circulation stroke. Methods. This prospective case series study involved the patients with the anterior circulation stroke and ultrasonographic criteria for unilateral hypoplasia of the ipsilateral IJV. Data from the 74 consecutive patients with acute anterior circulation stroke admitted to the Special Hospital for Cerebrovascular Diseases “Sveti Sava”, Belgrade, from September 2015 to January 2016 were included. Ultrasonography of IJV diameter and the collection of the hemodynamic data were performed in all patients. Neurological deficits on admission were evaluated using the National Institutes of Health Stroke Scale (NIHSS) score. The clinical outcome was assessed using the modified Rankin Scale (mRS) score (from 0 to 6) at 30 days or at discharge, whichever occurred sooner. Good and poor outcomes were defined as an mRS score of 0–2 and 3–6, respectively. Results. Ipsilateral hypoplastic IJV was diagnosed in 13 (17.6%) patients with anterior circulation stroke. In this group, 9 stroke patients (69.2%) had mRS ≥ 3. Of the remaining 4 patients with mRS ≤ 2, three had bilateral hypoplasia of IJV and one patient had smaller diameter of the IJV, but did not fulfill the ultrasonographic criteria for hypoplastic venous anomaly. Conclusions. In our case, a series of the patients with anterior circulation stroke with ultrasonographic criteria for unilateral hypoplasia of the ipsilateral IJV (on stroke side) have worse clinical outcome compared with the patients with bilateral hypoplasia.

There are two important conditions for the wide application of constitutive models for soil in contemporary engineering practice: a) the model should predict sufficiently well the soil behaviour at different stress paths; b) the material constants of the model can be determined from standard laboratory tests. Taking into account both conditions, a HASP model has been formulated to describe the mechanical behaviour of the overconsolidated clays, using the critical state theory and the boundary surface concept. The HASP model in a simple way overcomes many deficiencies of the Modified Cam Clay model, without introducing any additional material parameters. The formulation of the hardening rule in the function of the state parameter and overconsolidation ratio, allows the description of numerous elements of the mechanical behaviour of the overconsolidated clays. The HASP model has been implemented in software Abaqus using the Governing Parameter Method for the numerical integration of constitutive relations. The paper presents validation of the HASP model in comparison with the published results of triaxial tests as well as the possibilities of the model to adequately predict the behaviour of the overconsolidated clays through the analysis of the boundary value problem using the finite element method. The problem of the clay settlements due to phased construction of the embankment on the saturated clay surface was analyzed, assuming different overconsolidation ratios.

Products such as modular partition walls of vault rooms (with or without vault doors) are made at the request of the client who chooses the safety degree and provides the available dimensions of the wall that should be made. Modular construction of vault walls is the system of construction of industrially made elements which are composed in situ, which allows design of products adjusted to individual requirements of clients. Since the vault wall modules repeat in every new project and since they differ only by their number and dimensions, the use of modern CA (Computer Aided) tools and the possibility of application of parameter and variant design shorten design time and eliminate possible errors in the process of design of modular vault walls, which reduces the costs of production and increases the level of product quality. The paper presents the procedure for calculation of parameters of parts, modules and the entire vault wall in Microsoft Excel based on which the 3D model of a modular vault wall is automatically configured and developed in software package Autodesk Inventor. [Projekat Ministarstva nauke Republike Srbije, br. TR37020]

A specification of sawn timber is realized based on the previously designed log cutting plan, primary and secondary. The plan of primary log cutting (PPRT) has its verbal and mathematical interpretations. The theoretical aspect of PPRT design reported in the literature has great disadvantages. As it is based on the description and empirical combinations, such PPRT could hardly be evaluated as optimal. In addition to the above weakness, there is another one, i.e., the fact that the problem of PPRT design is reduced to a mono-criterion problem, i.e. the minimisation of total waste. If the problem of PPRT design is approached systematically, it is clear that the minimisation of total waste is only one out of a series of goals that a PPRT should fulfil. Nevertheless, the procedure presented in the literature is deeply rooted in practice. This paper, based on the on simulation principle, presents a modern procedure of PPRT design which consists of a number of phases. The first phase includes computer support in the design procedure of log cutting plans and also, a mono-criterion decision making in the selection of log cutting plans which ensure the minimal total waste per PPRT. The second phase includes the definition of another two criteria which are decisive for the optimal quality of PPRT. They are the log prices and the profit. Altogether 84 (eighty-four) cutting plans were designed and 4 (four) PPRTs. The solution of the problem, i.e. the design of an optimal PPRT in the conditions of three criteria, is based on multicriteria decision making using the method of Analytical Hierarchy Processes - AHP. The calculation is computed by the software Program Criterion Decision Plus - Version 3.0 Student version, InfoHarvest.Inc. In the study simulation of PPRT design, the optimal plan was PPRT3. The presented three criteria are not the final number. The inclusion of additional relevant criteria will depend on the inventiveness of the manager.

Cooperation, in combination with specialization, is aimed at the better utilization of resources, shorter production cycle and cost reduction. This means that cooperation and specialization, in addition to technological aspect, also include the organization aspect. The problem in wood processing is the fact that the organization aspect is completely neglected. For this reason, specialization and cooperation cannot reach their goal. The aim of this paper is to point out the significance of the organization aspect. The selection of cooperants cannot be based on the prices and acquaintances, recommendations, etc. There are numerous criteria which can decide the selection of cooperants. The criteria adopted in this paper are the manufacturing price and the storage cost. Based on the multicriteria decision making, it is possible to define the alternative which enables simultaneously the lowest total price and the lowest total own storage costs.

An active approach to the market means the full adaptation of the production system to the demands of the consumers, and the high profitability. To realize the above, production system should create the conditions for the simulation of the behavior of the system in real conditions. In the opposite the behavior of the system will be highly uncertain because of the disturbance in the system. The simulation of the behavior of the system in real conditions includes the existence of reliable information, obtained based on previous research. A series of such information also includes the information on the production cycle of a series of products. The components of the production cycle are also different disturbances. This paper analyses the failures of the technical system. This fact points to the significance of creating the conditions for forecasting the frequency and duration of the "failure". This paper, based on research of two formatisers, presents the methodology of carrying out the forecasting in real conditions.

The solution of problems in production is mainly tackled by the management based on the hardware component, i.e. by the introduction of work centres of recent generation. In this way, it ensures the continuity of quality reduced consumption of energy, humanization of work, etc. However, the interaction between technical-technological and organizational-economic aspects of production is neglected. This means that the new-generation equipment requires a modern approach to planning, organization, and management of production, as well as to economy of production. Consequently it is very important to ensure the implementation of modern organizational methods in wood processing. This paper deals with the problem of implementation of SMED method (SMED - Single Digit Minute Exchange of Die) in the aim of rationalization of set-up-end-up operations. It is known that in the conditions of discontinuous production, set-up-end-up time is a significant limiting factor in the increase of flexibility of production systems.

One of the specificities of the large-serial and mass production is the almost neglected percentage of prepare-finish time in the production cycle. In the conditions of today dominant discontinuous production, it becomes a significant element of the production cycle. The eastern (Japan) doctrine of increasing the flexibility of the production systems, is based inter alia also on the extreme reduction of the prepare-finish time. For this reason, the aim of this study was to identify the types and percentages of individual jobs within the group of prepare-finish jobs. The sample consisted of 3 (three) production systems for the production of joinery, with the discontinuous production system. The research shows that the percentage of time of the jobs installation of work instruments, regulation of processing regime, and removal of work instruments is extremely long and that it ranges between 11.83% and 18.93% of the shift time. The reasons of the high percentage of these jobs are the wide range of products and the absence of the rationalisation of prepare-finish jobs. Within the efforts to minimize the effects of disruption and to increase the flexibility of the production systems, the rationalisation of prepare-finish jobs is the unavoidable condition.

INTRODUCTION Medial rotation deformity of the hip is a problem to patients who are handicapped by cerebral palsy but able to walk, because the knees point inward during gait („kissing patellae") and cause falls and frequent injuries. Knees and ankles are subject to stress and, therefore, they assume compensating positions. Lower legs assume position of valgus and external rotation, whereas feet rotate either inwards or outwards. Secondary deformities make gait more difficult and cause rapid tear of footwear. AIM The purpose of the paper was to retrospectively analyze the effects of transposition of the gluteus medius and minimus muscles, a procedure introduced for the first time in our country in order to correct the deformity. A new method of binding the muscles by wire was described. There had been no previous experience with this method. METHOD This operation was indicated in patients with spastic form of cerebral palsy, who were able to walk, who had difficulties in gait and whose lateral rotation was less than 10° along with the medial rotation of over 70° of the hip on the side of the deformity. Additional prerequisite for the operation was the absence of flexion contracture of more than 15° of either the hip or the knee on the side of deformity, as there is possibility of aggravation of the flexion hip deformity due to transposed gluteal muscles (now in front of the hip joint). Fifteen hips of 10 patients were operated on. Five patients were operated on bilaterally at one time. The average age was 8 (6-12) years. The majority of patients, 8 (80%) were aged between 6 and 8. The average follow-up was 5 years (3-8). The assessment of the results was based on the comparison of rotational abilities of both hips before and after the operation (in unilateral and bilateral deformities), as well as on individual complaints before and after the operation. In patients with unilateral deformity, their „healthy" hips were the control hips. The analysis of the femoral neck anteversion before and after operation was performed. RESULTS Average values of medial and lateral rotation of the deformed hips before operation exhibited significant statistical difference when compared to control hips. The difference of average values of rotatory movements of control and operated hips was not statistically significant after operation. The difference of average preoperative values of the femoral neck anteversion in hips with deformity was statistically significant (49.40±4.63° compared to 32.8±3.1G). Postoperative average values of anteversion in operated and control hips were not statistically significant. The difference between average preoperative (49.40±4.63°) and postoperative (35.80±7.66°) values of the femoral neck anteversion was statistically significant. Excellent results were achieved in 5 (50%) patients, i.e. 8 (53.3%) hips; good results were achieved in 3 (30%) patients, i.e. 5 (33.3%) hips; poor result in 2 (20%) patients, i.e. 2 (13.3%) hips. All 5 patients who had undergone surgery of both hips had symmetric outcome. Three patients had excellent results, while two had good results. Patients with excellent and good results (80% of patients, 86.6% of hips) showed neither weakening of the operated hip abduction nor pelvic instability (positive Trendelenburgh hip test). No complications were recorded postoperatively. CONCLUSION Transposition of gluteal muscles can be recommended in patients under 10 years of age as there is still a chance for their femoral neck to change orientation, to decrease the anteversion and thus to achieve long-lasting effect. Fixation of transposed muscles by wire proved to be effective.

The absence of precise information on the magnitudes that determine the behavior of the production system generates the disturbances of the system. The consequence is the low efficacy of the system and the high costs. Therefore, it is necessary to create the base for the prediction of individual magnitudes and thus enable the simulation of the production system behavior in real conditions. The information on time norms has a special significance. It is the base of planning the terms and of defining a part of direct costs. Modern approach in the identification of standard times should be established on new foundations. It should appreciate the specificities of the present moment, as well as the future tendencies in wood processing. They are the production system dynamistic, conditioned predominantly by discontinuous production, as well as by the necessity of cooperation of the production systems. In this study, the approach to the identification of standard times is original, supporting the modern tendencies in wood processing and it has an applicative character.

This paper deals with actual European “modal shift to rail transport” concept and related environmental issues and experience in the Republic of Serbia. The planned increase in volume of railway transport and planned railway electrification should reduce air pollution in Serbia, particularly in the urban environment. On the other hand, achieving this goal would lead to the increase in noise level in the urban environment and environmental issues in the region of thermal power plants, which are the main sources of electricity in Serbia. This paper suggests concrete measures to reduce the railway carbon footprint and noise level during the planning, design and service life of railway infrastructure.