New photo-luminescent inorganic materials: high-tec application in chemical sensing and labeling

This thesis describes the potential of various kinds of luminescent nanoparticles with respect to chemical sensing and biosensing. First, fluorescent silica nanoparticles (SiNPs) were prepared by covalent attachment of fluorophores to the amino-modified surface of SiNPs with a typical diameter of 15 nm. The SiNPs were used in novel kinds of Förster resonance energy transfer (FRET)-based affinity assays at the interface between nanoparticle and sample solution. Various labels were employed to obtain a complete set of colored SiNPs, with excitation maxima ranging from 337 to 659 nm and emission maxima ranging from 436 nm to the near infrared (710 nm). The nanoparticles were characterized in terms of size and composition using transmission electron microscopy, thermogravimetry, elemental analysis, and dynamic light scattering. The surface of the fluorescent SiNPs was biotinylated, and binding of labeled avidin to the surface was studied via FRET in two model cases. Secondly, the upconverting luminescent nanoparticles (UCLNPs) consist of hexagonal NaYF4 nanocrystals doped with trivalent rare earth ions were synthesized by both the oleic acid (solvothermal) method and the ethylenediaminetetraacetic acid (coprecipitation) method. The nanoparticles were codoped using Yb3+ as the sensitizer ion, Er3+, Tm3+, or Ho3+ respectively as the emitting activator ions. An affinity system was demonstrated based on the interaction of two types of nanoparticles. The first type consists of UCLNPs of the type NaYF4:Yb,Er absorbing light in the infrared and showing green luminescence at 521 and 543 nm and red luminescence at 657 nm. The second type consists of gold nanoparticles (Au-NPs) with a size of about 50 nm, which absorb the green luminescence of the UCLNPs, but do not influence their red luminescence. A model system for a self referenced affinity system were established by labeling the UCLNPs with avidin and the AuNPs with biotin. In the presence of avidin-modified UCLNPs, the biotinylated Au-NPs can be detected in the range from 12 to 250 µg•mL-1 by rationing the intensity of the red (analyte-independent) emission band to that of the green (analyte-dependent) emission band. All nanoparticles were characterized in terms of size and composition using transmission electron microscopy, thermo-gravimetry, and FTIR spectroscopy. Thirdly, different types of nanoparticles (made from silica, polystyrene and UCLNPs) carrying longwave absorbing and emitting fluorescent labels were prepared by conjugating reactive dyes to the surface of amino-modified particles. The dyes have a reactive chloro group capable of reacting with amino groups and thereby undergoing a change in color, typically from green to blue (the so-called chameleon effect). The latter show the effect of upconversion in that near-infrared laser light is converted into visible luminescence. They also show the unusual property of displaying dual emission, depending on whether their luminescence is photoexcited with visible light or near-infrared light. The amino groups on the surface of nanoparticles were detected via the chameleon effect of the applied amino-reactive dyes. Fourth, the quenching effect of heavy metal ions and halide ions on the luminescence of UCLNPs in aqueous solution was studied. The effect was investigated for the ions Cu(II), Hg(II), Pb(II), Cd(II), Co(II), Ag(I), Fe(III), Zn(II), bromide and iodide, and was found to be particularly strong for Hg(II). Stern-Volmer plots were virtually linear up to 10 – 25 mM concentrations of the quencher, but deviate from linearity at higher quencher concentrations where static quenching caused an additional effect. The UCLNPs display two main emission bands (blue, green, red or near-infrared), and the quenching efficiencies for these found to be different. The effect seems to be generally associated with UCLNPs because it was observed for all particles doped with trivalent lanthanide ions including Yb(III), Er(III), Ho(III), and Tm(III)

BAYESIAN TWO-SAMPLE PREDICTION OF THE GENERALIZED PARETO DISTRIBUTION WITH FIXED AND RANDOM SAMPLE SIZES BASED ON GENERALIZED ORDER STATISTICS

Bayesian predictive intervals for future observations from a future sample from the generalized Pareto distribution (GPD) based on generalized order statistics (GOS) are obtained when the shape parameter is unknown. We consider two cases: (i) fixed sample size (FSS), and (ii) random sample size (RSS).Some closed forms for the Bayesian predictive functions are obtained. Finally examples are calculated for the lower and the upper bounds of the future observations in cases when the future sample is ordinary order statistics (OOS), record values and progressive type II censoring with different values for the scale parameter &nbsp

Creativity as a Part of the Post-Pandemic Architectural Education: A Brief Discussion

The current study discusses the importance of the creativity in architectural education, with a focus on the challenges and their implications on students, educators, and institutions. This study revisits a vision of an educational model for post-pandemic architecture education and discuss the necessary approaches for educators and educational institutions to foster creativity. This study directly reacts to the demand on the pandemic's effect on conventional education by using an instructional approach. This paper contributes to reconceptualizing of a novel approach that is targeted to tackle architectural education challenges in a post pandemic age through foster creativity models. The proposed creativity models are creative and critical thinking, neutral and positive stress, and objective-based creativity. These models are further developed using a thematic analysis process to be integrated in the educational model

Optimal Microgrids Placement in Electric Distribution Systems Using Complex Network Framework

This paper provides a new approach to find the optimal location for Microgrids (MGs) in electric distribution systems using complex network analysis. An optimal location in this paper refers to a location that would result in increased grid resilience, reduced power losses, less line loading, higher voltage stability and secured supply to critical loads during power outage. The criteria used to find the optimal placement of MGs were based on the centrality analysis adopted from complex network theory, the center of mass concept used in physics, and the controlled delivery grid (CDG) concept. An IEEE 30-bus system was used as a case study. Results using MATLAB and PowerWorld show the effectiveness of the proposed methodology to be used for MG placement

GEOCHEMISTRY, URANIUM, THORIUM AND RARE EARTH ELEMENTS OF TRACHYTE DYKES OF UMM SALATIT MOUNTAIN AREA, CENTRAL EASTERN DESERT, EGYPT

Umm Salatit Mountain area is a part of the Central Eastern Desert of Egypt. It is composed of ophiolitic mélange, older granitoids, biotite granites, muscovite granites and post granitic dykes and veins. Purpose of the work. The present work deals with the detailed investigations of the geology, petrography, geochemistry and spectrometric prospecting of the studied trachyte dykes as a possible source of uranium mineralization. Research methods. This work involves both field work (Construction of geological map with the structural features, scale 1 : 50,000, Spectrometric measurements of the different rock units using a portable gamma-ray spectrometer RS-230) and laboratory work (preparation of thin sections for petrographic studies by polarizing microscope), Atomic Emission Spectroscopy (AES), and Mass-Spectrometer with Inductively Coupled Plasma (ICPMS). Results. Petrographically, trachyte dykes consist mainly of K-feldspar with relatively minor amount of plagioclase, iron oxides, quartz and biotite. Secondary minerals are represented by sericite, muscovite, chlorite, carbonates and epidote. Accessory minerals are represented by opaque minerals. Trachytic textures are the main characteristic feature in trachyte. Geochemically, the investigated trachyte dykes were originated from an alkali magmarich in total alkalis, and the tectonic setting is continental basalt. Trachyte dykes have steep LREEs, nearly flat HREEs and a negative Eu anomaly. The negative Eu anomaly is either due to the partitioning of Eu into feldspar during fractionation, which is an important process in developing alkalinity, or the presence of residual feldspar in the source. Another alternative explanation for the negative Eu anomaly is based on the high oxygen fugacity in the melt due to volatile saturation. In general, all trachyte samples show moderate enrichment of most large ion lithophile elements (LILE) and high field strength elements (HFSE) and depletion of P, Ti and K. The depletion of Ti and p is ascribed to fractionation of titanomagnetite and apatite. The determination of equivalent uranium, thorium (ppm), potassium % and dose rate (m Sv/y) radiometrically by using portable RS-230 indicates that the dose rate in the trachyte dykes ranges from 0.5 to 1.5 with an average of 1.2 (m Sv/y). The radiometric data of the radioelements for them show a wide variation in eU and eTh contents. The eU content ranges from 2 to 14 ppm with an average of 6.6 ppm and the eTh content ranges from 4 to 37 ppm with an average of 18.03 ppm. Both U and Th correlate similarly with other major and trace elements, reflecting their geochemical coherence during the crystallization of the magma

Terlipressin versus norepinephrine to counteract intraoperative paracentesis induced refractory hypotension in cirrhotic patients

AbstractBack groundSome of tense ascitic patients with end stage liver disease and portal hypertension were presented to our emergency department with surgical acute abdomen that required urgent abdominal surgery which might be associated with inevitable rapid and relatively complete evacuation of this ascitic fluid with possible occurrence of post-paracentesis-induced hypotension. The aims of this study were to compare between the intraoperative use of terlipressin versus norepinephrine for the management of paracentesis induced refractory hypotension not responding to colloid resuscitation or ephedrine in patients with end-stage liver disease during emergency abdominal surgery.Patients and methodThirty-four patients experienced refractory hypotension during or shortly after the paracentesis process were randomized to receive either bolus dose of terlipressin (1mg over 30min) followed immediately by a continuous infusion of 2μg/kg/h (T group, n=17) or norepinephrine infusion at starting dose of 0.1μg/kg/min (N group, n=17).MeasurementsHemodynamic parameters, cardiac output, systemic vascular resistance, blood gases, lactic acid, liver and kidney functions.ResultsAll patients of both groups showed significant decreases in MAP during or immediately after the paracentesis process to reach mean values of 57±1.4 and 58±1.8mmHg in terlipressin or norepinephrine groups respectively. This was associated with drop in the SVR that reached mean values of 445±28 and 425±20 dynes/sec/cm5 in both terlipressin and norepinephrine groups respectively. At the 2nd day post operative there was significant increase in serum creatinine values in the norepinephrine group.ConclusionTerlipressin and norepinephrine successfully counteracted the post-paracentesis refractory hypotension and the drop of the systemic vascular resistance. It also showed the renal protective effects of terlipressin in the immediate postoperative period

Impact of Communication Latency on the Bus Voltage of Centrally Controlled DC Microgrid during Islanding

Maintaining a sustainable and reliable source of energy to supply critical loads within a renewable energy based microgrid (MG) during blackouts is directly related to its bus voltage variations. For example, voltage variation might trigger protection devices and disconnect DERs within the MG. Centrally controlled MGs (CCMGs) type is dependent on communication. Therefore, it is very important to analyze the impact of communication networks performance degradation, such as latency, on the bus voltage of CCMGs. This paper investigates the effect of wireless communication technologies latency on the bus voltage and performance of centralized DC MGs. Two mathematical models were developed to describe the behavior of microgrids during latency. As a case study, a renewable energy- based DC microgrid with its centralized control scheme was simulated to validate and compare the developed mathematical models. Results verify the accuracy of the developed models and show that the impact may be severe depending on the design, and the operational condition of the MG before latency occurs

Applications of Complex Network Analysis in Electric Power Systems

This paper provides a review of the research conducted on complex network analysis (CNA) in electric power systems. Moreover, a new approach is presented to find optimal locations for microgrids (MGs) in electric distribution systems (EDS) utilizing complex network analysis. The optimal placement in this paper points to the location that will result in enhanced grid resilience, reduced power losses and line loading, better voltage stability, and a supply to critical loads during a blackout. The criteria used to point out the optimal placement of the MGs were predicated on the centrality analysis selected from the complex network theory, the center of mass (COM) concept from physics, and the recently developed controlled delivery grid (CDG) model. An IEEE 30 bus network was utilized as a case study. Results using MATLAB (MathWorks, Inc., Nattick, MA, USA) and PowerWorld (PowerWorld Corporation, Champaign, IL, USA) demonstrate the usefulness of the proposed approach for MGs placement

Effect of Wireless Communication Delay on DC Microgrids Performance

This paper investigates the effect of wireless communication technologies latency on the converters and the bus voltage of centrally communication based controlled DC microgrids (MGs) during islanding. A DC microgrid with its communication based control scheme was modeled to show the impact of latency. Simulation results show that the impact may be severe depending on the design, and the operational condition of the microgrid before latency occurs