Semiconductor Gas Sensors: Materials, Technology, Design, and Application

This paper presents an overview of semiconductor materials used in gas sensors, their technology, design, and application. Semiconductor materials include metal oxides, conducting polymers, carbon nanotubes, and 2D materials. Metal oxides are most often the first choice due to their ease of fabrication, low cost, high sensitivity, and stability. Some of their disadvantages are low selectivity and high operating temperature. Conducting polymers have the advantage of a low operating temperature and can detect many organic vapors. They are flexible but affected by humidity. Carbon nanotubes are chemically and mechanically stable and are sensitive towards NO and NH3, but need dopants or modifications to sense other gases. Graphene, transition metal chalcogenides, boron nitride, transition metal carbides/nitrides, metal organic frameworks, and metal oxide nanosheets as 2D materials represent gas-sensing materials of the future, especially in medical devices, such as breath sensing. This overview covers the most used semiconducting materials in gas sensing, their synthesis methods and morphology, especially oxide nanostructures, heterostructures, and 2D materials, as well as sensor technology and design, application in advance electronic circuits and systems, and research challenges from the perspective of emerging technologies. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Karakterizacija endopeptidaza srednjeg creva larvi Morimus funereus (Coleoptera: Cerambycidae)

Application of specific chromogenic substrates, use of class-specific inhibitors, and zymogram analysis enabled us to identify several peptidase classes in extracts of the midgut of Morimus funereus larvae. Zymogram analysis with gelatin as a peptidase substrate and phenylmethylsulfonyl fluoride as an inhibitor showed that serine peptidases were the most abundant endopeptidases in the midgut of M. funereus larvae. By zymogram analysis with gelatin as a peptidase substrate and 1,10-phenanthroline as an inhibitor, metallopeptidases were also detected. Analyses of serine peptidases with specific chromogenic substrates revealed dominance of elastase-like peptidases in extracts of the midgut of M. funereus larvae, with less pronounced chymotrypsin- and trypsin-like activities.Primenom specifičnih hromogenih supstrata, klasno-specifičnih inhibitora i zimogramske analize identifikovano je nekoliko klasa peptidaza u sirovom ekstraktu srednjeg creva larvi koleoptere Morimus funereus. Zimogramskom analizom sa želatinom kao supstratom i fenilmetilsulfonil-fluoridom kao inhibitorom utvrđeno je da su serin-peptidaze najzastupljenije peptidaze u ekstraktu srednjeg creva larvi M. funereus. Zimogramskom analizom sa želatinom kao supstratom i 1,10-fenantrolinom kaoinhibitorom takođe su detektovane metalopeptidaze. Analizom serin-peptidaza, upotrebom specifičnih hromogenih supstrata, dokazano je da su dominantni elastazi-slični enzimi u sirovom ekstraktu srednjeg creva larvi M. funereus, dok su himotripsinima- i tripsinima-slični enzimi manje zastupljeni

Signal-to-Noise Ratio in Adsorption-Based Microfluidic Bio/Chemical Sensors

The noise due to stochastic fluctuations of the number of adsorbed analyte particles, caused by random adsorption-desorption (AD) process coupled with analyte convection and diffusion, is inherent to adsorption-based bio/chemical sensors. It posses the fundamental limit for the detection of analyte. In this study we perform an analysis of the signal-to-noise ratio (SNR) of microfluidic sensors, taking into account their AD noise. We have shown that mass transfer significantly influences the possibility to achieve the acceptable SNR value. It also influences the minimal detectable concentration and also the time necessary to reach the SNR value that ensures reliable real-time detection and quantification of the analyte

Ubiranje soje kombajnom Claas Lexion 430 -ekploatacioni parametri

Soya (Glycine) is one of the most important crop plant. It produces products for human and domestic animals and processing industry. It is an important protein and oil plant. The soybean seeds contain more proteins (35-50%) and fats (17-24%) and fewer carbohydrates than others leguminous plants. Research of the Claas Lexion 430 combine harvester in a mercantile soybeans harvest shown that losses in uncut pods were in all measurements above tolerant 2% and ranged from 2.46% to 2.94%. Losses on the thresher in the free grain were ranged from 0.18% to 0.34% on average to 0.26%, which is satisfactory in relation to the given 0.3%. The average losses in the unthreshedpods are 0.35%, which is more than the projected level, but for the conditions of harvesting it can be accepted as satisfactory, due to the large percentage of weeds in the field.Soja (Glycine) je jedna od najvažnijih ratarskih kultura, od koje se dobijaju proizvodi važni u ishrani ljudi i domaćih životinja i za preradu u industriji. Soja je važan izvor belančevina i ulja. Seme soje sadrži više proteina (35- 50%) i masti (17- 24%), a manje ugljenih hidrata od ostalih mahunastih biljaka. Kombajn Claas Lexion 430 posle eksploatacionih istraživanja imao je u žetvi merkantilne soje gubitke u neodrezanim mahunama u svim merenjima iznad tolerantnih 2%. Ovi gubici su bili u intervalu od 2,46 % do 2,94 %. Kombajn Claas Lexion 430 na vršalici ima gubitke u slobodnom zrnu koji su varirali od 0,18% do 0,34 % (proseku 0,26%), što je zadovoljavajuće u odnosu na zadatih 0,3 %. Prosečni gubici u neovršenim mahunama su 0,35 %, što je više od projektovanog nivoa, ali se za uslove ubiranja mogu prihvatiti kao zadovoljavajući, iz razloga značajne zakorovljenosti parcele

Morphometric analysis of collagen and inflammatory cells in periodontal disease

© 2015, Institut za Vojnomedicinske Naucne Informacije/Documentaciju. All rights reserved. Background/Aim. Periodontal disease affects gingival tissue and supporting apparatus of the teeth leading to its decay. The aim of this study was to highlight and precisely determine his-tological changes in the gum tissue. Methods. Gingival biopsy samples from 53 healthy and parodontopathy-affected patients were used. Clinical staging of the disease was performed. Tissue specimens were fixed and routinely processed. Sections, 5 μm thin, were stained with hematoxylin and eosin, histochemical Van-Gieson for the collagen content, Spicer method for mast-cells and immunochemical method with anti-CD68 and anti-CD38 for the labelling of the macrophages and plasma-cells. Morphometric analysis was performed by a M42 test system. Results. While the disease advanced, collagen and fibroblast volume density decreased almost twice in the severe cases compared to the control ones, but a significant variation was observed within the investigated groups. The mast-cell number increased nearly two times, while the macrophage content was up to three times higher in severe parodontopathy than in healthy gingival tissue. However, the relative proportion of the-se cells stayed around 6% in all cases. Plasma-cells had the most prominent increase in the number (over 8 times) com-pared to the control, but again, a variation within investigated groups was very high. Conclusion. Gingival tissue destruction caused by inflammatory process leads to significant changes in collagen density and population of resident connective tissue cells. Although inflammatory cells dominated with the disease advancing, a high variation within the same investigated groups suggests fluctuation of the pathological process

Uklanjanje fenola i fenolnih derivata iz vode imobilizovanom polifenol-oksidazom iz krompira

Phenols containing halogens, which tend to deactivate the aromatic nuclei, constitute a significant category of highly toxic and difficult-to-degrade pollutants, which arise from a wide variety of industries. The main purpose of this study was to obtain an inexpensive immobilized enzyme for the removal of phenols. Partially purified potato polyphenol oxidase (PPO) was immobilized onto different commercial and laboratory produced carriers. Three of the obtained biocatalysts, with the highest PPO activities, namely Eupergit C250L-PPO; Celite-PPO and CelluloseM-PPO, were tested in a batch reactor for the removal of phenol, 4-chlorophenol and 4-bromophenol. In the case of 2.5 mM substrates with Eupergit C250L-PPO, an around 45 % removal of 4-bromophenol was achieved, while the removals 4-chlorophenol and phenol were 35 and 20 %, respectively. The reusability of Eupergit C250L-PPO for the removal of 4-chlorophenol was tested. After eight repeated tests, the efficiency of 4-chlorophenol removal by Eupergit C250L-PPO immobilisate had decreased to 55 %.Halogenovani fenoli imaju dezaktivirano aromatično jezgro i čine značajnu kategoriju veoma toksičnih i teško razgradivih zagađivača u raznim industrijskim granama. Glavni cilj ovog rada je bio dobijanje jeftinog imobilizovanog enzima za uklanjanje fenola. Delimično prečišćena polifenol-oksidaza (PFO) iz krompira je imobilizovana na različitim komercijalnim i laboratorijski sintetizovanim nosačima. Od dobijenih biokatalizatora, tri sa najvećim aktivnostima PPO, nazvani Eupergit C250L-PFO; Celit-PFO i CelulozaM-PFO, testirani su u reaktoru za uklanjanje fenola, 4-hlorfenola i 4-bromfenola. U slučaju 2,5 mM supstrata sa Eupergit C250L-PFO, postignuto je oko 45 % razgradnje 4-bromfenola, dok su 4-hlorfenol i fenol razgrađeni 35, odnosno 20 %. Testirana je i sposobnost višestruke upotrebe Eupergit C250L-PFO imobilizata za uklanjanje 4-hlorfenola. Nakon osam ponovljenih ciklusa efikasnost Eupergit C250L-PFO imobilizata za uklanjanje 4-hlorfenola je pala na 55%

The effectiveness of resistance genes derived from Aegilops spp. to wheat rusts

In this paper resistance of nearly isogenic lines with genes Sr32, Sr33, Lr9, Lr21 and Lr22 derived from Ae. squarrosa and Ae. umbellulata is presented. The genes Sr32 and Sr33 showed good effectiveness to different pathotypes of wheat stem rust in seedling stage. But, in adult stage lines with this genes were moderately resistant to very susceptible in Kragujevac and Zajeear. The most effective was gene Lr9. In our population of wheat leaf rust there is no alleles of virulence to this gene. The lines with other two genes (Lr21 and Lr22) were susceptible in Novi Sad and moderately susceptible in Kragujevac. Studies showed that Aegilops spp. is very important source of Sr and Lr genes of resistance

Cytotoxicity of Platinum(Iv) and Palladium(Ii) Complexes with Meso-1,2-Diphenyl-Ethylenediamine-N,N -Di-3-Propanoic Acid. Crystal Structure of [Pd(1,2-Dpheddp)] Complex

The syntheses of tetradentate ligand, meso-1,2-diphenyl-ethylenediamine-N,N-di-3-propanoic acid (H-2-1,2-dpheddp) and corresponding platinum(IV) and palladium(II) complexes are reported here. The spectroscopically predicted structure of the obtained palladium(II) complex was confirmed by X-ray analysis. Singe crystals suitable for X-ray measurements were obtained by slow crystallization from a DMSO-water mixture. Cytotoxic effects of platinum(IV), palladium(II) complexes and cisplatin on the 4T1 and Bl6F1 cell lines were determined using the MTT colorimetric technique. The complexes showed a dose dependence on cytotoxic effect toward both cell lines. Both complexes were less active than cisplatin, the exception was concentrations above 62.5 mu M of platinum(IV) complex in the B16F1 cell line