The Review of Materials for Energy Harvesting

This paper presents a short review of the piezoelectric materials in energy harvesting. Energy harvesting principle, as the method for obtaining energy from environment has been described. Materials and material combinations for creating an energy harvesting composites are discussed, such as ceramic- and polymer-based composites and their mechanical properties. The list of the mostly used piezoelectric materials is presented and elaborated. Possible applications of the energy harvesting materials are discussed, including nanogenerators, biosensors and biomedical applications.10.13039/100010686-EIT's HEIAccepted for publishin

Electrospinning As The Fabrication Technology For The Energy Harvesting Composites

This paper presents the electrospinning technology as used for the fabrication of the energy harvesting composites, including the review of ceramic-based and polymer-based piezoelectric composites and their electrical outputs for the energy harvesting applications. Energy harvesting is a method for obtaining electrical energy from the environment to be used for powering autonomous electronic devices. Current trend of reducing the size of the devices has led to the increasing number of new energy harvesting materials. Basic principles of fiber fabrication via electrospinning were presented, as well as material characterization methods. The special focus was given to the electrical properties of energy harvesting composites with a review of methods for detecting and measuring electrical outputs of these materials. Electrical performance of the electrospun piezoelectric nanogenerators was discussed.SMART-2M, Innovation Capacity Building for Higher Education in Industry 4.0 and Smart Manufacturing, European Institute of Innovation and Technology (EIT), the European Union’s Horizon 2020 research and innovation program under grant agreement 777204 and projects No. 451-03-9/2021-14/200107 and No. 451-03-9/2021-14/200378, Ministry of Education, Science and Technological Development, SerbiaPublishe

Тбилисская Неделя N42

ყოველკვირეული გაზეთი სრული ტელეპროგრამით; Еженедельная газета с полной телепрограммо

Real-time detection of traffic events using smart cameras

With rapid increase of number of vehicles on roads it is necessary to maintain close monitoring of traffic. For this purpose many surveillance cameras are placed along roads and on crossroads, creating a huge communication load between the cameras and the monitoring center. Therefore, the data needs to be processed on site and transferred to the monitoring centers in form of metadata or as a set of selected images. For this purpose it is necessary to detect events of interest already on the camera side, which implies using smart cameras as visual sensors. In this paper we propose a method for tracking of vehicles and analysis of vehicle trajectories to detect different traffic events. Kalman filtering is used for tracking, combining foreground and optical flow measurements. Obtained vehicle trajectories are used to detect different traffic events. Every new trajectory is compared with collection of normal routes and clustered accordingly. If the observed trajectory differs from all normal routes more than a predefined threshold, it is marked as abnormal and the alarm is raised. The system was developed and tested on Texas Instruments OMAP platform. Testing was done on four different locations, two locations in the city and two locations on the open road

Stabilization of a-glucosidase in organic solvents by immobilization on macroporous poly(GMA-co-EGDMA) with different surface characteristics

a-Glucosidase from baker’s yeast was immobilized on macroporous copolymers of ethylene glycol dimethacrylate and glycidyl methacrylate, poly(GMA-co-EGDMA), with various surface characteristics and pore sizes ranging from 44 nmto 270 nm. Immobilization was done by glutaraldehyde on the copolymer previously modified with 1,2-diaminoethane. The specific activity of the obtained immobilized enzyme varied from 27 to 81 U/g, depending on the employed copolymer. The half lives of the immobilized enzyme in cosolvents were influenced by the surface characteristics of the copolymer, ranging from 60 to 150 min in 35 % methanol and from 10 to 44 min in 45 % dimethyl sulphoxide (DMSO). The best stabilities were obtained when the enzyme was immobilized onto a copolymer having a pore size of 48 nm in methanol and 270 nm in DMSO

Preparation and studies on immobilized α-glucosidase from baker’s yeast Saccharomyces cerevisiae

α-Glucosidase from S. cerevisiae was covalently immobilized onto Sepabeads EC–EA by the glutaraldehyde method. An analysis of the variables controlling the immobilization process is first presented and it is shown that the highest coupling of α-glucosidase occurred within 24 h. Also, a loading of 30 mg/g support proved to be effective, resulting in a rather high activity of around 45 U g–1 with a satisfactory degree of enzyme fixed. Both free and immobilized enzymes were then characterized by determining the activity profile as a function of pH, temperature and thermal stability. The obtained immobilized preparation showed the same optimum pH, but a higher optimum temperature compared with the soluble one. In addition, the immobilized enzyme treated at 45 ºC for 1 h still retained an activity of around 20 %, whereas the free enzyme completely lost its original activity under this condition. In conclusion, the developed immobilization procedure is quite simple, easily reproducible and provides a promising solution for the application of immobilized α-glucosidase

Neuroimaging Modalities Used for Ischemic Stroke Diagnosis and Monitoring

Strokes are one of the global leading causes of physical or mental impairment and fatality, classified into hemorrhagic and ischemic strokes. Ischemic strokes happen when a thrombus blocks or plugs an artery and interrupts or reduces blood supply to the brain tissue. Deciding on the imaging modality which will be used for stroke detection depends on the expertise and availability of staff and the infrastructure of hospitals. Magnetic resonance imaging provides valuable information, and its sensitivity for smaller infarcts is greater, while computed tomography is more extensively used, since it can promptly exclude acute cerebral hemorrhages and is more favorable speed-wise. The aim of this article was to give information about the neuroimaging modalities used for the diagnosis and monitoring of ischemic strokes. We reviewed the available literature and presented the use of computed tomography, CT angiography, CT perfusion, magnetic resonance imaging, MR angiography and MR perfusion for the detection of ischemic strokes and their monitoring in different phases of stroke development

Brixia Chest X-ray Score, Laboratory Parameters and Vaccination Status for Prediction of Mortality in COVID-19 Hospitalized Patients

Chest X-ray has verified its role as a crucial tool in COVID-19 assessment due to its practicability, especially in emergency units, and Brixia score has proven as a useful tool for COVID-19 pneumonia grading. The aim of our study was to investigate correlations between main laboratory parameters, vaccination status, and Brixia score, as well as to confirm if Brixia score is a significant independent predictor of unfavorable outcome (death) in COVID-19 patients. The study was designed as a cross-sectional multicentric study. It included patients with a diagnosed COVID-19 infection who were hospitalized. This study included a total of 279 patients with a median age of 62 years. The only significant predictor of unfavorable outcome (death) was Brixia score (adjusted odds ratio 1.148, p = 0.022). In addition, the results of the multiple linear regression analysis (R2 = 0.334, F = 19.424, p p = 0.046), severe COVID-19 (B = 1.970, p p p < 0.001) was a significant negative predictor of Brixia score. Our results provide important information about factors influencing Brixia score and its usefulness in predicting the unfavorable outcome (death) of COVID-19 patients. These findings have clinical relevance, especially in epidemic circumstances

The specificity of alpha-glucosidase from Saccharomyces cerevisiae differs depending on the type of reaction: hydrolysis versus transglucosylation

Our investigation of the catalytic properties of Saccharomyces cerevisiae alpha-glucosidase (AGL) using hydroxybenzyl alcohol (HBA) isomers as transglucosylation substrates and their glucosides in hydrolytic reactions demonstrated interesting findings pertaining to the aglycon specificity of this important enzyme. AGL specificity increased from the para(p)- to the ortho(o)-HBA isomer in transglucosylation, whereas such AGL aglycon specificity was not seen in hydrolysis, thus indicating that the second step of the reaction (i.e., binding of the glucosyl acceptor) is rate-determining. To study the influence of substitution pattern on AGL kinetics, we compared AGL specificity, inferred from kinetic constants, for HBA isomers and other aglycon substrates. The demonstrated inhibitory effects of HBA isomers and their corresponding glucosides on AGL-catalyzed hydrolysis of p-nitrophenyl a-glucoside (PNPG) suggest that HBA glucosides act as competitive, whereas HBA isomers are noncompetitive, inhibitors. As such, we postulate that aromatic moieties cannot bind to an active site unless an enzyme-glucosyl complex has already formed, but they can interact with other regions of the enzyme molecule resulting in inhibition