Breathing solitons in nematic liquid crystals

Dynamical and steady-state behavior of beams propagating in nematic liquid crystals (NLCs) is analyzed. A well-known model for the beam propagation and the director reorientation angle in a NLC cell is treated numerically in space and time. The formation of steady-state soliton breathers in a threshold region of beam intensities is displayed. Below the region the beams diffract, above the region spatiotemporal instabilities develop, as the input intensity and the material parameters are varied. Curiously, the only kind of solitons we could demonstrate in our numerical studies was the breathers. Despite repeated efforts, we could not find the solitons with a steady profile propagating in the NLC model at hand

BALANCE IN YOUNG GYMNASTS: AGE-GROUP DIFFERENCES

The aim of this study was to investigate difference in balance test scores and success on the balance beam of young gymnasts, international level of competition. Forty eight young gymnasts divided into two age groups participated in the study (Group 1: n=22, age 9.0 ± 1.1 years, 136.0 ± 7.6 cm, 30.8 ± 4.3 kg; Group 2: n=26, 12.1 ± 0.6 years, 146.0 ± 7.0 cm, 36.9 ± 6.6 kg;). To assess static balance, participants performed 3 stance variations (double leg, single leg, and tandem leg) on stiff surfaces and 3 specific static-balance tests consist of gymnastics elements on the balance beam (Scale, handstand and side handstand). For assessment of dynamic balance, participants performed multidirectional maximal single-leg reaches from a unilateral base of support (Y - balance test) and 3 specific dynamic-balance tests consisted of two connected gymnastics elements (Turns for 360°, jumps with 180º  and cartwheels). In the static balance test there is a significant difference only in one-leg stance (SRJN, .021) and specific static balance test SSSU (.000). In the dynamic balance tests, there was a significant difference in performing SD2Z test between the two groups (p=.043). These results suggests that the older gymnasts had better results in demanding tests such as one-leg stance, handstand and cartwheels on the balance beam. To achieve top results in the Women's Artistic gymnastics it is necessary to achieve good results on the balance beam and monitoring of balance ability for future success

Strukturiranje ekološki prihvatljivih elastomernih kompozitnih materijala

For the waste rubber recycling, it is obligative to know the chemical composition of the waste products, if it is to be used in the new composite elastomeric material formulation. The composite elastomeric materials obtained from the waste rubber powder have a very diverse application (farm floors, sports stadiums, tyres production, in construction as a vibration protection material). The aim of this work was to prepare elastomeric composites based on recycled elastomer powder (REP). A few types of elastomeric materials were synthesized based on natural rubber, polybutadiene rubber, styrene-butadiene rubber, (NR/BR/SBR, 40/40/20 phr), carbon black and recycled elastomer powder were synthesized. It was assessed that composites NR/BR/SBR/REP have shorter optimum curing time tc90 than samples without REP. By increasing the REP content the tc90 value and tensile strength are decreasing, but the abrasion resistance is increasing.Kod recikliranja otpadne gume neophodno je poznavati hemijski sastav otpadnog proizvoda, ukoliko će se on koristiti u recepturama za nove hibridne elastomerne materijale. Kompozitni elastomerni materijali dobijeni od praha otpadne gume imaju veoma raznovrsnu primenu (podovi na farmama, sportski stadioni, dobijanje pneumatika, u građevinarstvu kao materijali za zaštitu od vibracija itd). Cilj ovog rada je bio da se dobiju elastomerni kompoziti na osnovu reciklirane gume. Sintetisano je nekoliko tipova elastomernih materijala na osnovu prirodnog kaučuka, stiren-butadienskog kaučuka i polibutadienskog kaučuka (NR/BR/SBR, 40/40/20 phr), čestica čađi i recikliranog gumenog praha. Ustanovljeno je da kompoziti NR/BR/SBR/REP imaju kraće optimalno vreme umrežavanja u poređenju sa uzorcima NR/BR/SBR bez REP. Porastom količine REP smanjuje se vreme optimalnog umrežavanja i prekidna črstoća, a povećava se otpornost na abraziju

Renal cancer and Wegener's granulomatosis: a case report

Wegener's granulomatosis (WG) is a systemic disorder characterized by necrotizing vasculitis involving the respiratory tract, and in most cases, the kidneys. The most common manifestation of WG in the kidneys is segmental necrotizing glomerulonephritis. The presence of a renal mass as a manifestation of WG is rare. We report a patient with WG in whom a CT scan revealed an infiltrating mass in the lower portion of the left kidney. After surgical exploration, we performed an open radical nephrectomy. Histopathology showed clear cell type renal cell carcinoma (RCC). RCC associated with WG has been reported in only a few cases, and in most of them, the diseases started simultaneously, suggesting common pathogenetic pathways. Long-term immunosuppressive treatment is a known risk factor in the development of malignancies, so occurrence of RCC in WG has been proposed as a side effect of cyclophosphamide treatment. Furthermore, it is important to make a differential diagnosis between RCC and pseudotumors in WG as they cannot be distinguished solely on basis of imaging findings. Due to the higher risk of urologic malignancies, more frequent checkups and screening of WG patients should be considered

Recurrent painful ophthalmoplegic neuropathy: A report on the patient from the Romani population and 82-year-old patient

© 2020 Inst. Sci. inf., Univ. Defence in Belgrade. All rights reserved. Introduction. The current diagnostic criteria for recurrent painful ophthalmoplegic neuropathy (RPON) are at least two attacks of unilateral headache, associated with ipsilateral paresis of one, two or all three cranial nerves (III, IV or VI). There is no case report about RPON in the Romany population. The oldest patient with RPON, published in the literature, was 74 years old. Case report. The first patient was a 31-year-old man from the Romani population who was treated during three episodes of RPON, with III nerve palsy during one episode and with alternating VI nerve palsy during two episodes. All examination were normal except serum lipid levels and Cytomegalovirus immunoglobulin G (CMV IgG), Toxoplasma gondii IgG, Epstein-Barr virus (EVB) IgG and Varicella zoster IgG which were elevated. The second patient was a 82-year-old male patient with two RPON episodes with alternating VI nerve palsy. All examinations were normal, except Herpes simplex type 1 virus IgG, CMV IgG, Toxoplasma gondii IgG, EBV IgG and Varicella zoster IgG which were elevated, and his brain magnetic resonance imaging (MRI) showed lacunar ischemic lesions. Both patients were started on corticosteroid. Recovery was completed after all five episodes of RPON. Conclusion. There are no data on the frequency of RPON among the Romani population. The presentation of RPON in the oldest age is rare. RPON should be considered as a diagnostic option in these minorities. New case reports or systematic review articles about RPON are necessary to create a new insight into the nature of the disease

Non-Opioid Analgesics Consumption At The Surgery Departments Of A Secondary Care Hospital In General Hospital In Kraljevo, Serbia

The aim of this study was to determine the amount of non-opioid analgesics consumed at the surgical departments of a secondary care hospital in Serbia, a developing country undergoing a socioeconomic transition that thus lacks sufficient funds to finance and invest in the healthcare system

Prevalence of Asymptomatic Abdominal Aortic Aneurysm in Patients with Carotid Stenosis

The aim of this study was to demonstrate the prevalence of abdominal aortic aneurysm in patients with carotid disease and to analyse the influence of cardiovascular risk factors for abdominal aortic aneurysm. Methods: Ultrasound for abdominal aortic aneurysm was performed in 200 patients (112 men and 88 women, mean age 65.72±7.71 years) with known carotid disease. The primary cardiovascular risk factors (age, sex, hypertension, diabetes, dyslipidaemia and smoking) were analysed. Results: We found that 15.5% of patients with carotid stenosis also had abdominal aortic aneurysm. The prevalence of abdominal aortic aneurysm was higher in men (22.23%) than in women (6.81%). There was no correlation between the severity of carotid disease and the diameter of the abdominal aortic aneurysm (p>0.05). Advanced age and smoking were independent risk factors for abdominal aortic aneurysm. Conclusion: These results demonstrate that the prevalence of abdominal aortic aneurysm is higher in patients with carotid disease than in the general population. Patients with known carotid disease may be candidates for selective screening for abdominal aortic aneurysm detection

Guided modes in left-handed waveguides

We investigate basic properties of linear guided modes in a waveguide slab with the core of a material with simultaneously negative effective permittivity and permeability surrounded by a normal dielectric cladding. The existence and dispersion of all possible types of guided modes have been studied in detail. We demonstrate that the two orthogonally polarized, TE and TM slow guided modes, with the same frequency and the same wave number can exist simultaneously. Their group velocities, however, can be parallel or anti-parallel