Lipoprotein(a) Is the Best Single Marker in Assessing Unstable Angina Pectoris

This study evaluated whether statin therapy changed a diagnostic validity of lipid and inflammatory markers in ischemic heart disease (IHD) patients. Levels of lipids, lipoproteins, apolipoproteins, inflammatory markers, and atherogenic indexes were determined in 49 apparently healthy men and women, 82 patients having stable angina pectoris (SAP), 80 patients with unstable angina (USAP), and 106 patients with acute ST-elevation myocardial infarction (STEMI) treated or not treated with statins. Diagnostic accuracy of markers was determined by ROC curve analysis. Significantly lower apoA-I in all statin-treated groups and significantly higher apoB in statin-treated STEMI group compared to non-statin-treated groups were observed. CRP showed the best ROC characteristics in the assessment of STEMI patients. Lp(a) is better in the evaluation of SAP and USAP patients, considering that Lp(a) showed the highest area under the curve (AUC). Regarding atherogenic indexes, the highest AUC in SAP group was obtained for TG/apoB and in USAP and STEMI patients for TG/HDL-c. Statins lowered total cholesterol, LDL-c, and TG but fail to normalize apoA-I in patients with IHD

A Time Series Forest Method for automatic classification of anomalous glow curves of LiF:Mg,Ti based thermoluminescent dosemeters

Thermoluminescent dosimetry is a widely used passive dosimetry method for estimating protection quantities i.e. the effective or equivalent dose. When the thermoluminescent dosemeters (TLD) are irradiated, they store the dose information through the processes of ionisation and subsequent trapping of charge carriers. The charge carriers in TLD crystalline material move from the ground state to the higher energy states (trapping centres) that are partially stable at room temperature. By heating the material, charge carriers leave the metastable energy states and recombine at recombination centres, emitting light (glow). The heating procedure gives rise to a glow curve (GC) – the light intensity as a function of temperature and time. By calibrating the TLD reader, the area under the GC is converted to a dose value (e.g., personal dose equivalent, Hp(10)). The shape of the GC depends on the time-temperature profile (TTP) defined for each TLD material separately and may be regular or possess some anomalies. Inspecting the GC shape, as one of quality control measures, is usually conducted qualitatively and performed by trained TLD service staff. Hence, this paper presents the implementation of the machine learning Time Series Forest (TSF) method for the classification of anomalous GCs of LiF:Mg,Ti based TLD. TSF is a tree – ensemble method that combines entropy gain and distance measure for evaluating splits. This method shows significant computational efficiency compared to the well – known one – nearest – neighbour classifier. The dataset used for the TSF method consists of 201 normalized GCs exported by the software supplied with Harshaw 6600 Plus Automated Reader – WinREMS. The dataset is labelled into five different classes: (1) regular shape, (2) spikes at random positions, (3) TLD signal in the low – temperature region, (4) TLD signal in the high – temperature region, and (5) shift of the entire GC to higher temperatures. A random split of the dataset into training and testing in a 70/30 training/test ratio was performed, while the 10 – fold cross – validation was used for the hyperparameter tuning. The results showed that the TSF method can classify four different anomalies for GC with an accuracy of 96% and a macro average F1 score of 96%. According to the obtained results, it is possible to conclude that the TSF is a promising candidate method that could be implemented as a new software package for automated GC quality control within the TLD serviceRAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts; May 29 - June 2, 2023, Anavyssos, Greec

Uticaj pozicije kompresione papučice na HVL merenja u mammografiji

Clinical mammography units utilize compression paddle for breast compression during exposure. When compression paddle is released, it returns to a default position which varies between different mammography units. This default position is commonly used in quality control procedures. Guidelines for quality control testing in mammography propose measuring the half-value layer (HVL) by placing added filtration on compression paddle while multimeter is positioned on the mammography unit's detector. The influence of compression paddle positioning on HVL measurements was studied under laboratory conditions. The difference in HVL values with and without the presence of the plate is not insignificant, the positioning of the plate also has a significant impact on the measurements.Kliničke mamografske jedinice sadrže kompresione papučice koje se koriste u svrhe kompresije dojke prilikom ekspozicije. Nakon oslobađanja kompresione papučice ona se vraća u uobičajeni položaj koji se razlikuje među mamografskim jedinicama. Ova pozicija se najčešće koristi tokom testiranja pri kontroli kvaliteta. Protokoli za kontrolu kvaliteta u mamografiji predlažu merenje debljine poluslabljenja (HVL) postavljanjem dodatnih filtera na kompresionu papučicu dok se multimetar postavlja na detektor mamografske jedinice. Uticaj pozicioniranja kompresione papučice na HVL merenja je ispitan u laboratorijskim uslovima. Razlika u vrednostima za HVL sa i bez prisustva PMMA ploče nije zanemarljiva, dakle pozicioniranje ploče ima značajan uticaj na izmerene vrednosti.XXXII симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 4-6. октобар 2023. годин

Solid state detector energy response in W/Al mammography radiation quality series

Ionization chambers and solid state detectors incorporated into multimeters are often used for quality control in different modalities of medical imaging and diagnostic radiology. The equipment to be used in the routine QC procedures needs to be calibrated under well-known radiation conditions (known as radiation qualities) defined by the international standards. International standards IEC 61267:2005 [IEC 62167, IEC 2005] and IAEA TRS 457:2007 [IAEA TRS 457, IAEA 2007] cover general radiography and fluoroscopy radiation qualities (abbreviated as RQR and RQA series, in the voltage range from 40 kV to 150 kV), and computerized tomography radiation qualities (abbreviated as RQT series, in the voltage range from 100 kV to 150 kV), among other. In the field of mammography reference radiation fields are defined for molybdenum anode/filtration combination (Mo/Mo, abbreviated as RQR-M series, in the voltage range from 25 kV to 35 kV). Since Mo/Mo mammography units are widespread and available at hospitals they have been included in the standard [IEC 62167, IEC 2005]. Even so, Secondary Standard Dosimetry Laboratories (SSDLs) that are performing calibrations of QC dosimeters for end-users, rarely have availability of such anode/filtration combination under reference laboratory conditions. SSDLs most often employ X-ray generators with W/Al combinations. Additionally, nowadays many different combinations of anode/filtration are present in mammography units of different manufacturers that are commonly used in the hospitals. Multimeters are often sensitive to spectral changes caused by different anode/filter combination, so it is doubtful that the traceability established for one anode/filter combination can be used to measure doses for another combination. Measurements with different solid state detectors were performed under laboratory conditions with W/Al radiation qualities established in the SSDL. In the future, research will be expanded to clinical conditions in radiation fields produced by mammography units which employ Mo/Mo, Mo/Rh, Rh/Rh, W/Rh and W/Ag. Dosimeter response will be evaluated based on the dependency of 1st HVL which is correlated to radiation output of the X-ray generator (the incident photon spectra).RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts; May 29 - June 2, 2023, Anavyssos, Greec

Structure and enhanced antimicrobial activity of mechanically activated nano TiO2

Titanium dioxide is a photocatalyst, known not only for its ability to oxidize organic contaminants, but also for its antimicrobial properties. In this article, significant enhancement of the antimicrobial activity of TiO2 (up to 32 times) was demonstrated after its activation by ball milling. The antimicrobial activity was analyzed for one fungal and 13 bacterial ATCC strains using the microdilution method and recording the minimum inhibitory concentration (MIC) values. In order to further investigate the correlation between the mechanical activation of TiO2 and its antimicrobial activity, the structure, morphology and phase composition of the material were studied by means of Electron Microscopy, X-ray diffraction and nitrogen adsorption-desorption measurements. UV-Vis diffuse reflectance spectra were recorded and the Kubelka-Munk function was applied to convert reflectance into the equivalent band gap energy (E-g) and, consequently, to investigate changes in the E-g value. X-ray photoelectron spectroscopy was used to analyze the influence of mechanical activation on the Ti 2p and O 1s spectra. The presented results are expected to enable the development of more sustainable and effective advanced TiO2-based materials with antimicrobial properties that could be used in numerous green technology applications

Dielectric and Structural Properties of the Hybrid Material Polyvinylidene Fluoride-Bacterial Nanocellulose-Based Composite

In the search for environmentally friendly materials with a wide range of properties, polymer composites have emerged as a promising alternative due to their multifunctional properties. This study focuses on the synthesis of composite materials consisting of four components: bacterial nanocellulose (BNC) modified with magnetic Fe3O4, and a mixture of BaTiO3 (BT) and polyvinylidene fluoride (PVDF). The BT powder was mechanically activated prior to mixing with PVDF. The influence of BT mechanical activation and BNC with magnetic particles on the PVDF matrix was investigated. The obtained composite films’ structural characteristics, morphology, and dielectric properties are presented. This research provides insights into the relationship between mechanical activation of the filler and structural and dielectric properties in the PVDF/BT/BNC/Fe3O4 system, creating the way for the development of materials with a wide range of diverse properties that support the concept of green technologies

A high-sensitive current-mode pressure/force detector based on piezoelectric polymer PVDF

This paper introduces new electronic sensor circuits based on the usage of a piezoelectric Polyvinylidene fluoride-PVDF pressure detector coupled with a current-mode instrumentation amplifier, Schmitt comparator, and only grounded resistors. Pressure/force is measured in terms of the charge generated by the PVDF element as a result of the direct piezoelectric effect. The experimental test results demonstrated that the dynamic pressure response, the sensitivity and linearity of the designed sensor were higher than the sensitivity and linearity of a traditional piezoelectric sensor. The sensitivity of the PVDF sensor was 0.08 mV/Pa. The detector is calibrated over a frequency range of 1 Hz-1 kHz. The proposed signal conditioning electronics offer a potential for future miniaturization in order to be integrated with different commercial devices, for detecting certain tiny activities including finger movements, robotics and smart electronic devices

Behavior of sulfur-polymer matrix composites with different fillers under acid and salt influence

Based on the nature of the matrix material, modern composites can be generally classified into three categories: polymer matrix composites, metal matrix composites, and ceramic matrix composites. Polymer matrix composites are not as strong or heat-resistant as metal matrix and ceramic matrix composites and therefore are restricted to secondary structures in which operating temperatures are lower than 300° C while for higher temperatures, metal matrix and ceramic matrix composites are required. Polymeric materials based on inorganic components can play an important role in various technological processes but their production on an industrial scale is still problematic. However, inorganic polymers, in combination with other materials can generate composite materials of very high quality and possibilities of applications. Among plenty of inorganic materials that can generate polymer chains, special attention should be paid to sulfur. One of the most popular applications of waste sulfur from the oil refining process is to produce a modified sulfur binder, which is predominantly implemented in different compositions of sulfur- polymer matrix composite materials used for diverse applications. Using sulfur as a binder is based on its physical and chemical characteristics: chemical passivity, excellent resistance to aggressive agents (mainly acids and salt solutions, but not bases) and hydrophobic properties. Sulfur implementation for composites production has started with using unmodified sulfur as a binder. However, despite excellent mechanical properties after preparation, samples exhibited low stability, so spalling and failure occurred after a short period. The development of modified sulfur binder contributed to better endurance of sulfur- polymer matrix composites, which focused its application for roads construction and repairing and as a building material. Sulfur itself tends to polymerize to a large extent while chemical modification increases this tendency or prolongs the time required for the polymerization. Except the prevention of sulfur transformation from monoclinic to orthorhombic form, the degree of sulfur polymerization is increased and long chains are created due to modification. Sulfur- polymer matrix composites are thermoplastic materials made of mineral aggregate and filler, with sulfur as a binder (instead of cement and water) at temperature above the hardening point of sulfur (120 °C). The proportion of aggregate, filler and binder for the preparation of sulfur- polymer matrix composite mixture may vary depending on the application. The choice of filler is important because it forms with sulfur paste that coats and binds the aggregate particles. In this chapter, various fillers were used for the production of sulfur- polymer matrix composite samples: talc, alumina, microsilica and fly ash. Durability of the obtained sulfur- polymer matrix composite samples was investigated under influence of acids (hydrochloric and sulfuric acids) and salt (sodium chloride) by monitoring their physico-mechanical characteristics. It was concluded that the used filler had influence on the behavior of the sulfur- polymer composite samples in the investigated environments

Expression of CD34 and CD146 vascular markers contributes to the immunological function of the human palatine tonsil

The fundamental function of the palatine tonsil is the immune response to airborne and foodborne pathogenic agents. Small blood vessels have an important role in the provision of a special microenvironment in which the immune response occurs. In this study, we investigated the expression of vascular markers CD34 and CD146 and basal lamina marker - type IV collagen - in the small blood vessels of the human palatine tonsil in the context of their role in the immunological function of the tonsil. The tonsils were collected after tonsillectomy from ten patients with chronic tonsillitis, aged 18-28 years. Five-µm-thick paraffin sections were routinely stained with haematoxylin and eosin, while the studied markers (CD34, CD146 and type IV collagen) were detected immunohistochemically using LSAB2/HRP method. CD34 was expressed equally in the capillaries within and below the crypt epithelium, in lymphoid follicles and in high endothelial venules localized para- and interfollicularly. CD146 molecule was expressed on the luminal surface of endothelial cells in the capillaries of the crypt epithelium, while its expression in high endothelial venules was seen on the luminal and lateral surfaces of the cuboidal endothelial cells. In contrast to the basal lamina of intraepithelial capillaries, where collagen IV-immunopositivity is mostly seen as a continuing line, the basal lamina of high endothelial venules was seen as a two- or three-layered structure beneath the cuboidal endothelial cells. The specifics of expression of CD34, CD146, and type IV collagen confirm the morphofunctional specialization of endothelium in crypt epithelium capillaries, and also in endothelium of high endothelial venules, which is directly associated with the role of these vessels in the immune function of the tonsil