21 research outputs found

    3D random fiber composites as a repair material for damaged honeycomb cores

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    Povećana upotreba kompozitnih materijala donela potrebu za razvojem pouzdanih i efikasnih tehnika popravki. Kao i sve druge noseće metalne strukture i kompozitne strukture sklone su oÅ”tećenjima. Razvijene tehnike popravki metalnih konstrukcije nisu direktno primenljive na kompozite i problem popravki kompozitnih struktura mora biti detaljno proučen. U ovom radu analizirana je primena kompozitnih materijala sa slučajnim rasporedom vlakana, kao materijalom za popravku oÅ”tećenih saćastih jezgara visoke gustine sendvič konstrukcija. Pomoću Panove teorije izveden je izraz potrebnog zapreminskog udela vlakana materijala popravke i određeno je kompletno naponsko deformaciono stanje popravljene kompozitne stukture metodom konačnih elemenata. Zaključeno je da kompozitni materijali sa slučajnim rasporedom vlakana predstavljaju veoma dobre kandidate za popravku oÅ”tećenih kompozitnih struktura sa saćastim jezgrima.The increased use of composites has rendered the need for development of reliable and efficient repair techniques. Like all other metallic structures composite structures are prone to variety of damage. Repair techniques developed for metallic structures are not directly applicable to composites and problem of composite repair has to be investigated in great detail. In the present paper application of 3D random fiber polymer composites, as a repair material for damaged high density honeycomb cores in sandwich structures is investigated. Based on Pan 's theory the expression for matching fiber volume fraction of the repair material is derived and complete stress-strain field, of the repaired sandwich structure is determined using finite element approach. It is concluded that the 3D random fiber composites represent very good candidates as repair materials for damaged honeycomb structured composites

    Isolated eyeball metastasis of non-seminomatous germ cell testicular tumor

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    Introduction. Testicular tumors most frequently metastasize to regional lymph nodes. Non-seminomatous tumor metastasis of testicle (NSGCTT) to the eyeball is rare. Case report. We presented a 24-year old man, referred to the ophthalmologist due to acute pain and abrupt loss of sight in the left eye accompanied by its enlargement. Orbital and endocranial computerized tomography (CT) was carried out, indicating the tumor in the left eye. His previous medical history provided the information that the right testicle was painlessly enlarged for 8 months. Ultrasonography showed a completely tumorously altered testis. Abdominal and chest CT failed to reveal any secondary deposits in visceral organs and lymph glands. Tumor markers (AFP - alpha-fetoproteins, beta hCG - human choronic gonadotropin beta) were elevated. Right radical orchiactomy was performed (showed NSGCTT), followed by polychemotherapy with cisplatinum 100 mg/m2, etoposide 120 mg/m2, bleomycin 15 mg/m2 (PEB Ā“ 4), resulting in normalization of tumor marker values and significant regression of the left eyeball. Next, the left eye enucleation and ocular prosthesis implantation was carried out. Pathohistological evaluation indicated fibrosis and necrosis only. In a 5-year follow-up period, the patient was free of recurrence. Conclusion. Isolated hematogenous metastasis of the NSGCTT to the eye is rare. In our case, the left eye was the only metastatic localization. After chemotherapy and eye enucleation the patient was in a 4- year follow-up period free of the recurrence

    Maternal smoking during pregnancy and socioeconomic factors as predictors of low birth weight in term pregnancies in NiÅ”

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    Background/Aim. Low birth weight (LBW) is a result of preterm birth or intrauterine growth retardation, and in both cases is the strongest single factor associated with perinatal and neonatal mortality. It is considered that socioeconomic factors, as well as mothers bad habits, play the most significant role in the development of LBW, which explains notable number of researches focused on this particular problem. The aim of this study was to characterize socioeconomic factors, as well as smoking habits of the mothers, and their connection with LBW. Methods. The questionnaire was carried out among mothers of 2 years old children (n = 956), born after 37 gestational weeks. The characteristics of mothers who had children with LBW, defined as < 2 500 g, (n = 50), were matched with the characteristics of mothers who had children ā‰„ 2 500 g, (n = 906). For defining risk factors, and protective factors as well, we used univariant and multivariant logistic modeles. Results. As significant risk factors for LBW in an univariant model we had education level of the mothers, smoking during pregnancy, smoking before pregnancy, the number of daily cigarettes, the number of cigarettes used during pregnancy, paternal earnings and socioeconomic factors. In a multivariant model the most significant factors were socioeconomic factors, education level of the mothers, paternal earnings and mothers smoking during pregnancy. Conclusion. Smoking during pregnancy and socioeconomic factors have great influence on LBW. Future studies should be carried out in different social groups, with the intention to define their influence on LBW and reproduction, as well. This should be the proper way of adequate health breeding planning for giving up smoking, the prevention of bad habits and melioration of mothers and children health, as the most vulnerable population

    Imaging Features of Triple N Negative Breast Cancers ā€“ Mammography, Ultrasound and Magnetic Resonance Imaging

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    Breast cancer (BC) is a highly heterogeneous disease. Aim was to evaluate imaging features of triple negative breast cancers (TNBC) in comparison to non-TNBC. We reviewed data of 30 patients who had been diagnosed as having TNBC and 37 patients with non-TNBC (control group) using criteria described for mammography (MMG), ultrasound (US) and magnetic resonance imaging (MRI) in Breast Imaging-Reporting and Data System (BI-RADS) lexicon for image interpretation. Age of patients, size of tumor, multifocality, histological type, tumor grade and status of lymph nodes were reviewed. TNBC were more often histological grade 3 and had significantly more positive lymph nodes at the time of diagnosis on pathology reports. On MMG, US and MRI TNBC mostly appeared as regularly shaped masses. On US as hypoechogenic masses with no posterior acoustic features and on MRI as masses with rim type of enhancement, fast wash-in and plateau type of curves. Most frequent category reported after MMG and US was BI RADS 4, and after MRI BI RADS 5. In conclusion, our study confirmed higher histological grade of TNBC, as well as more frequent lymph node involvement in comparation to the non-TNBC. TNBC showed tendency to affect younger women and to be larger than non-TNBC. Although, they most often presented as a mass on mammography and sonography, in a significant number of cases they remained miscategorized, due to the benign imaging features. All cases are recognized on MRI where they appear as rim enhancing masses

    The Polymorphisms of Genes Encoding Catalytic Antioxidant Proteins Modulate the Susceptibility and Progression of Testicular Germ Cell Tumor

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    The simultaneous analysis of redox biomarkers and polymorphisms encoding for regulatory and catalytic antioxidant proteins was performed in order to evaluate their potential role in the development of testicular germ cell tumor (GCT), as well as the progression of the disease. NRF2 (rs6721961), GSTM3 (rs1332018), SOD2 (rs4880) and GPX3 (rs8177412) polymorphisms were assessed in 88 patients with testicular GCT (52 with seminoma) and 88 age-matched controls. The plasma levels of 8-hydroxy-2ā€²-deoxyguanosine (8-OHdG), thiol groups and the plasma activity of glutathione peroxidase were measured. A significant association between variant GPX3*TC+CC genotype and risk of overall testicular GCT, as well as seminoma development, was found. Moreover, carriers of variant SOD2*TT genotype were at almost 3-fold increased risk of seminoma development. Interestingly, combined SOD2*TT/GPX3*TC+CC genotype conferred a 7-fold higher risk for testicular GCT development. Finally, variant GSTM3*AC+CC genotype was associated with a higher risk for the development of advanced diseased. The presence of assessed genetic variants was not associated with significantly higher levels of redox biomarkers in both testicular GCT patients, as well as in those diagnosed with seminoma. In conclusion, the polymorphic expression of certain antioxidant enzymes might affect susceptibility toward testicular GCT development, as well as the progression of the disease

    Interplay between Comprehensive Inflammation Indices and Redox Biomarkers in Testicular Germ-Cell Tumors

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    Sustained and dysregulated inflammation, concurrent tumor-induced immune suppression, and oxidative stress are profoundly involved in cancer initiation, presentation, and perpetuation. Within this prospective study, we simultaneously analyzed the preoperative indices of systemic inflammatory response and the representative byproducts of oxidative DNA, protein, and lipid damage with the aim of evaluating their clinical relevance among patients diagnosed with testicular germ-cell tumors (GCT). In the analytical cohort (n = 88, median age 34 years), neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), and C-reactive protein (CRP) were significantly altered in patients with a higher tumor stage (p < 0.05). Highly suggestive correlations were found between NLR, dNLR, and SII and modified nucleoside 8-OHdG. CRP and albumin-to-globulin ratio (AGR) significantly correlated with thiols group level and maximal tumor dimension (p < 0.05). Based on receiver operating characteristic (ROC) curve analyses, all the evaluated pre-orchiectomy inflammation markers demonstrated strong performance in predicting metastatic disease; optimal cut-off points were determined for each indicator. Although further large-scale studies are warranted, inflammatory and redox indices may both complement the established tumor markers and standard clinicopathological prognostic variables and contribute to enhanced personalized risk-assessment among testicular GCT patients

    Understanding the Male Perspective: Evaluating Quality of Life and Psychological Distress in Serbian Men Undergoing Infertility Treatment

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    The experience of an infertility diagnosis and treatment imposes a profound burden on affected individuals, encompassing not only physical and medical aspects but also a plethora of psychological, social, and emotional factors. By employing a multimodal assessment featuring validated self-report questionnaires, physical measurements, and clinical records, the present study aimed to explore the quality of life and psycho-emotional distress of men undergoing infertility treatment in Serbia, thereby addressing the dearth of research on the underrepresented male perspective in this domain. Findings revealed diverse semen abnormalities among participants (n = 96, average age 37.69 Ā± 5.72), with significant associations between longer treatment durations and reduced sperm motility. The observed rates of men surpassing predetermined DASS-42 questionnaire thresholds for depression, anxiety, and stress in the analyzed cohort were 13.54%, 11.46%, and 22.92%, respectively. Summary scores in conceptual areas comprised in the SF-36 questionnaire ranged from 49.00 Ā± 6.25 for the mental health dimension to 90.16 Ā± 17.75 obtained in the physical functioning subscale. Patients with a longer treatment duration demonstrated lower scores in the role emotional domain, indicative of a less favorable emotional state. Expectedly, inverse correlations were found between the SF-36 mental health score and DASS-42 subscales. By addressing the existing knowledge gap and highlighting the unique needs of infertile men, the finding of this study may contribute to a more inclusive and holistic approach to infertility research and management

    Contemporary problems of transmission and interaction of quantum generators with material

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    Savremena problematika vezana za kvantne generatore u optičkom i RF delu spektra traži kao eksperimentalnu podrŔku vrlo kompleksne i skupe sisteme i komponente. Zbog toga su računarske simulacije neizbežne u osnovi razvoja mnogih sistema. U radu se autori bave problematikom dizajna optičkih vlakana i drugih komponenata u svrhe modulacija i simulacija u makroskopskim komponentama optičkih sistema. U drugom delu rada se primenom softverskih aplikacija ocenjuju eksperimentalni rezultati interakcije sa kvantnim generatorima na odabranoj vrsti materijala.Contemporary issues related to the quantum generators in the optical and RF spectral ranges required as part of the experimental support very complex and expensive systems and components. Therefore, the simulation is basically inevitable development of many systems. The authors deal with the problem of design of optical fiber and other components for the purpose of modulation and simulation of optical components in macroscopic systems in this paper. In the second part of it the application of other software types applications evaluated experimental results of interaction for selected type of material with the quantum generators

    Retail and Housing Complex [award: Recognition in Non realization category BAB 2023]

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    Related to the immediate context of the site, the architectural approach was to provide a balance within the mixed-use development, such as residential, commercial and public space facilities. Common principles for the integration of residential activities, social infrastructure and the public realm, ensure a central public landscaped environment at the ground level with vertical integration of residential blocks at upper levels. The public areas have been located around the main pedestrian square, to allow the commercial components to be oriented both on community residents and passing trade from non-residents. The majority of the residential development within the site is given over to the low-rise building of 4 stories high. The design approach allows residents to be able to retreat to tranquil private external spaces at the upper levels. On the other side, the additional small building at the front clearly defines the boundaries of public space and main pedestrian routes inside the location.3d: LjubiÅ”a Bogićevi
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