Hrčak - Portal of scientific journals of Croatia
Not a member yet
321498 research outputs found
Sort by
Rizici postave implantata kod pacijenata s bruksizmom
Get PDFBruksizam, koji se definira kao ponavljajuća aktivnost žvačnih mišića koja uzrokuje stiskanje i škrgutanje zubima, može dovesti do komplikacije implantoprotetske terapije. Rizik koji nosi bruksizam proizlazi iz činjenice da pacijenti s bruksizmom proizvode jake i konstantne okluzalne sile koje su čak i jače kod implantata nego prirodnih zuba. Kao razlog navodi se nedostatak parodontnog ligamenta koji u sebi sadži proprioreceptore. Implantološka terapija kod pacijenata s bruksizmom gotovo je neizbježna s obzirom na veliki broj postavljenih implantata godišnje te visoku prevalenciju samoga bruksizma. Iako danas još ne postoje znanstveni dokazi koji bi bruksizam svrstali u kontraindikacije implantološke terapije, potreban je oprez pri postavi implantata kod takvih pacijenata. Bruksizam može dovesti do bioloških i mehaničkih komplikacija implantata. Mehaničke se komplikacije viđaju češće, ali kasnije od bioloških. Njihova uloga je bitnija zbog složenosti liječenja. Biološke uključuju probleme oseointegracije i periimplantitisa, dok su mehaničke vezane za sam implantat, abutment, vijak ili protetski rad koji se nalazi na implantatu. Stomatolog treba biti svjestan rizika koje nosi bruksizam te ih objasniti pacijentu
THE EFFECT OF FREEZE-DRIED Lactiplantibacillus plantarum I ON THE MICROBIOLOGICAL QUALITY OF QUEEN SCALLOP Aequipecten opercularis
Get PDFU ovoj studiji četiri odabrana soja bakterija mliječne kiseline morskog podrijetla osušena su smrzavanjem, koristeći obrano mlijeko kao krioprotektor. Nakon sušenja smrzavanjem, stope preživljavanja određene su pod 24-satnom izloženošću uzorcima morske vode. Izolat Lactiplantibacillus plantarum I imao je najveću stopu preživljavanja od 92,5% i odabran je za daljnje pokuse. Liofilizirani soj Lpb. plantarum I dodan je na mjesec dana školjkašima češljači (Aequipecten opercularis Linnaeus, 1758) u kružnim bazenima pod uvjetima klimatskih promjena (promjene temperature i pH). Nakon perioda hranjenja školjkaši su sakupljeni i za svakog češljača je određena mikrobiološka kakvoća. Rezultati pokazuju da je dodatak Lpb. plantarum I značajno poboljšao mikrobiološku kvalitetu kultiviranih češljača. Ukupan broj bakterija zajedno sa vrstama Staphylococcus značajno je smanjen, a dodani soj bakterija mliječne kiseline uspio se održati u željenim količinama tijekom cijelog perioda hranjenja. Dobiveni rezultati pokazuju da bi uključivanje Lpb. plantarum I kao dodatak prehrani moglo pružiti zaštitu od kvarenja i poslužiti kao moguć pristup za smanjenje razine patogena tijekom uzgoja A. opercularis u zatočeništvu.In this study, four selected strains of lactic acid bacteria of marine origin were freeze-dried using skim milk as a cryoprotectant. After freeze-drying, survival rates were determined under 24-hour exposure to seawater samples. Isolate Lactiplantibacillus plantarum I had the highest survival rate of 92.5% and was selected for further experiments. Freeze-dried Lpb. plantarum I strain was added to queen scallop Aequipecten opercularis (Linnaeus 1758) in circular basins under climate change conditions (temperature and pH modifications) for one month. After the feeding period, shellfish were collected and microbiological quality was determined for each scallop. The results indicate that the addition of Lpb. plantarum I significantly improved the microbiological quality of the cultivated scallops. The total number of bacteria together with Staphylococcus species was significantly reduced, and the added lactic acid bacteria strain was maintained at desired amounts during the entire feeding period. The results obtained indicate that the inclusion of Lpb. plantarum I as a dietary supplement could provide spoilage protection and serve as a feasible approach to reduce pathogen levels when cultivating A. opercularis in captivity
An ANP-Hopfield Neural Network Based Approach for Supply Chain Stress Testing
Get PDFSupply chain resilience is increasingly critical in today's globalized and volatile business environment. This study proposes a novel approach to supply chain stress testing by combining Analytic Network Process (ANP) with Hopfield Neural Networks. The method constructs a stress testing index system based on product review, elasticity, agility, and cultural motivation. ANP is used to weight each index, while a discrete Hopfield neural network is employed to design equilibrium points corresponding to different stress levels. The model is applied to an automobile manufacturing case study, demonstrating its effectiveness in classifying supply chain stress levels. Results show that the proposed method can effectively identify key factors affecting supply chain stress and provide a comprehensive evaluation of supply chain resilience. This approach offers a new tool for supply chain managers to assess and enhance their networks' ability to withstand external pressures
Enhanced Low Power FinFET-Based Flash ADC Design for High-Speed Electronics Applications
Get PDFIn electronics applications, signals are often of very low amplitude and frequency, making them susceptible to distortion and noise, which are unavoidable issues. Over the last few decades, Complementary Metal Oxide Semiconductor (CMOS) technology has been the most widely used process technology for mobile communication devices, biomedical systems, and image processing. However, conventional CMOS comparators suffer from stacking and driving current limitations, and face significant second-order effects below the 45 nm process node. In this paper, we present the circuits of Flash analog-to-digital converters (ADCs) specifically designed for mobile and biomedical applications. Flash ADCs are ideal for high-speed and wide-bandwidth applications, where comparators and encoders are crucial components of the ADC architecture. The main objective of this work is to design low-power, enhanced current-driving circuits for Flash ADCs. This is achieved by designing a FinFET-based comparator, encoder, and supporting circuits for ADCs in a 32 nm process. Our investigation shows that performance degrades at higher speeds below 32 nm, but our modified double-tail comparator and encoder unit effectively reduce power consumption while improving current-driving capabilities. This work builds upon previous research conducted at the 180 nm CMOS process level. For implementation, we investigated Taiwan Semiconductor models for CMOS and FinFET at 45 nm, 32 nm, and 14 nm using Synopsys HSPICE
VFed-PU: Identifying Containers with Potential to be Shipped by Rail from Ports with Privacy Protection
Get PDFFacing challenges in the global container shipping market and strict data protection laws like GDPR and CCPA/CCPR, the sea-rail intermodal transportation sector urgently needs better freight demand forecasting. This study develops a micro-level transportation demand forecasting model tailored for the sea-rail intermodal sector, emphasizing data privacy and accurate prediction of port demand for container shipments by rail, which is crucial for effective railway planning and marketing. We introduce a novel framework, VFed-PU, which combines Vertical Federated Learning with Positive and Unlabeled Learning. This model tackles issues such as limited labeled data, data imbalance, and selection bias using a new method called ImbalancednnPUSB. VFed-PU ensures data privacy by transferring only data representations rather than the original data during model training, safeguarding sensitive information among different parties. Extensive experiments demonstrate that VFed-PU outperforms state-of-the-art algorithms in predicting port demand for container shipments, achieving a recall rate of approximately 90%. This framework not only enhances prediction accuracy and preserves data privacy but also supports strategic railway planning and marketing efforts. The study highlights the importance of data privacy in transportation planning, especially under stringent data protection regulations, and contributes significantly to the field by addressing both forecasting performance and privacy concerns
An Analysis of Transition Temperature for Real and Simulated Heat Affected Zone of HSLA Steel
Get PDFThe aim of this paper is to present the analysis of the influence of different test temperatures on the impact toughness of the real heat affected zone (RHAZ) and the simulated heat affected zone of the welded joint (SHAZ) of high strength low-alloy steel. Through thermal cycle simulation, which includes heating to a certain temperature and programmed cooling, the microstructure of different areas of the heat-affected zone was obtained on the samples, which allows us to directly draw appropriate conclusions regarding the real heat-affected zone of the welded joint. Based on the previous text, a comparison of the brittleness transition temperature values for RHAZ and SHAZ as a very important factor for structural steels was made. It has been observed that with a decrease in temperature many metals exhibit a sudden decrease in toughness, so the temperature at which the material transits from ductile to brittle fracture is called brittle transition temperature (ductile-brittle transition temperature). This indicator is very important regarding further design and exploitation of welded steel structures
Research on the Theoretical Mechanism and Path of AI and Digital Economy Empowering High Quality and Balanced Development of Urban and Rural Education
Get PDFThe aim of this study is to investigate the impact of AI and digital economy development on the high-quality and balanced development of urban and rural education in China's provinces from 2015 to 2020. By the MIMIC model, this research incorporates AI initiatives and digital economy indices as key variables and applies two-way fixed effects models to analyze their influence. Robustness checks with alternative variables and endogeneity tests further validate the findings. The results reveal an inverted U-shaped relationship between AI development and educational outcomes, indicating initial benefits that diminish beyond a certain point. Conversely, the digital economy consistently enhances educational quality and accessibility, particularly in rural areas. These findings align with existing literature and underscore the importance of optimal technology integration in education. The study concludes that, while AI and digital economy initiatives significantly improve educational outcomes, it also shows the coefficients for AI (0.495), AI² (‒0.434), DEB (‒0.550), and DEB² (0.589) along with their error margins. Policy makers should consider these insights to effectively plan and monitor the integration of technological advancements in education
Errors in Measuring Height Differences in Engineering
Get PDFFor classic geodetic instruments, sources of errors influencing the total measurement error were determined. In digital levels, the technique of comparing the current image of the graduated rod with the saved picture of the graduated rod is used to read the rod. This reading technique eliminates the subjective influence (operator's error), but an error occurs from comparing two images. Apart from this source of errors, several errors in rod reading are not present at classical levels. Experimental measurements with digital levels have proven that certain sources of errors, which other authors also processed, can be significant concerning the accuracy of measurements. For example, illumination at 45° or steeper angles can cause reading errors more than ten times the measurement error at the station. Or, that inhomogeneous illumination of some parts of the rod causes large measurement errors, up to a few millimetres. One source of error has not been considered so far - this is the error that arises from incorrect sighting on the rod. Experimental measurements confirmed that misalignment caused an error of the order of tenths of a millimeter, and which can be larger than the measurement error at the station. It was also confirmed that this error is not characteristic only for one type of digital level, but it is already being reported in all. This error can be greater than the mean error of measuring the height difference at the station, which is significant in engineering works where height/height difference is often measured or marked using only one station
The 9th Regional Symposium on Electrochemistry -South East Europe
Get PDFThe 9th Symposium on Electrochemistry -South East Europe (RSE-SEE9) was held from June 3 to June 7, 2024, in Novi Sad, the second-largest city in Serbia and the capital of Vojvodina Province. The Symposium took place at the University of Novi Sad, in the Rectorate building, within the university’s green campus near the Danube. It gathered electrochemists from the region to discuss recent research and developments in the field. The Electrochemical Division of the Serbian Chemical Society and the Faculty ofTechnology, University of Novi Sad, organized the event