Wyniki wyszukiwania - Biblioteka Nauki

1

Sectrofluorometric characterisation of the lubricate oil

100%

Baszanowska E. , Otremba Z.

Journal of Polish CIMAC

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2014

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tom Vol. 9, no 2

17--22

EN

Exploitive features of lubricate oils are externalised by various physical and chemical parameters (for example temperature dependencies of density and viscosity, ignition point or water content). On the other hand it is well-known that fluorescence spectra of various types of crude oils and their derivatives are strongly differ from each other. It is reasonable thesis, that exploitive features of oil may be related to transformations of light inside the oil. Therefore, despite of that fact light transformations strongly depend on chemical composition of oil (especially from the content of cyclic and polycyclic molecules). No one can exclude, that physical conditions are for fluorescence processes closely related to changes of physical and chemical properties of oil (and consequently to exploitive features) as well as to newly arising compounds and intrusions (for example metals, caused by contact with various engine elements). The paper presents spectra of fluorescence of exemplary lubricate oil (Marinol) in various configurations, namely: emission spectrum for individual excitation wavelength, excitation spectrum for single emission wavelength, excitation-emission spectrum, synchronous fluorescence spectroscopy and total synchronous fluorescence spectroscopy. Dynamic structures of those spectra gives reason to conclude that shapes of fluorescence spectra may be controlled by exploitive features of oils.

2

Porównanie liniowych metod PCA (Principal Component Analysis) i LDA (Linear Discriminant Analysis) zastosowanych do klasyfikacji matryc wzbudzeniowo-emisyjnych wybranych grup substancji biologicznych

100%

Leśkiewicz M. , Kaliszewski M. , Mierczyk Z. , Włodarski M.

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tom Vol. 65, nr 1

15--31

PL

W pracy porównano właściwości dwóch liniowych metod (PCA i LDA) pozwalających na redukcję wymiarów w trakcie analizy cech oraz zbadano wydajność tych dwóch algorytmów w procesie klasyfikacji wybranego materiału biologicznego na podstawie jego wzbudzeniowo-emisyjnych matryc fluorescencyjnych. Stwierdzono, że metoda LDA redukuje liczbę wymiarów (znaczących zmiennych) bardziej efektywnie niż metoda PCA. Za pomocą algorytmu LDA udało się uzyskać względnie dobre rozróżnienie badanego materiału biologicznego.

EN

Quality of two linear methods (PCA and LDA) applied to reduce dimensionality of feature analysis is compared and efficiency of their algorithms in classification of the selected biological materials according to their excitation-emission fluorescence matrices is examined. It has been found that LDA method reduces the dimensions (or a number of significant variables) more effectively than PCA method. Arelatively good discrimination within the examined biological material has been obtained with the use of LDA algorithm.

3

Aktywność katalityczna pojedynczych cząsteczek enzymów

100%

Jakubaszek J. , Molski A.

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tom [Z] 62, 7-8

635-658

EN

As early as in 1961, it has been demonstrated that turnovers of individual enzyme molecules can be detected [1]. In the nineties, advances in single-molecule methods, in particular in confocal microscopy (Fig. 1), made it possible to monitor more closely enzymatic turnovers at a single-molecule level [2-5]. This led to the discoveries of static disorder and dynamic disorder, and closely related memory effects in enzymatic turnovers [6-8]. Differences in activity of individual molecules of the same enzyme are called static disorder. Time-dependent fluctuations of enzymatic activity are called dynamic disorder. One manifestation of dynamic disorder is the fact that consecutive enzymatic turnovers are not statistically independent, which is called "memory effect". It is believed that static dis-order and dynamic disorder are related to conformational dynamics of enzyme molecules. In this review we discuss current issues of single-molecule enzymology, in particular kinetic effects that are specific to single-enzyme measurements. First we review the conceptual basis of single-enzyme kinetics and the initial work on single enzymes. We focus on the ping-pong mechanism of bisubstrate enzyme reactions (Eqs. (1) and (2)), and consider fluorescence trajectories (Figs. 2 and 3) associated with enzymatic turnovers. Two cases are distinguished. In the first, fluorescence comes from an enzyme molecule and fluorescence intensity jumps called blinking carry information on enzymatic activity. Jumps between a fluorescent (on) and non-fluorescent (off) states (Eqs. (4), (5), and Fig. 2) indicate the moments when the photophysical state of an enzyme changes during enzymatic turnovers. In the second case, fluorescence comes from product molecules whereas enzyme and substrate are non-fluorescent. Fluorescence bursts on a trajectory indicate the moments when non-fluorescent substrate molecules are converted into fluorescent product molecules that subsequently diffuse away from the detection volume (Eqs. (8), (9) and Fig. 3). In Section 1 we present selected experiments implying the effect of conformational dynamics on enzymatic kinetics. In Section 1.1, we discuss cholesterol oxydase and dihydroorotate dihydrogenase as examples of enzymes whose on-off fluorescence blinking is caused by chemical reactions at the enzyme active site. In Section 1.2 we discuss ?-lactosidase and lipase B as enzymes which turnovers can generate fluorescent products from suitably chosen non-fluorescent substrates. In Section 2, we review modeling and simulations of single-enzyme data. The aim of data modeling is to gain insight into single-enzyme activity through analysis of models of increasing complexity. Phenomenological models attempt to capture the essence of single-enzyme kinetics without going into molecular details. If a model is simple enough it may allow analytical solutions. For instance, a simple model of on-off blinking is given in Scheme (25). This scheme is capable of reproducing memory effect that can be visualized by a two-dimensional histogram of consecutive on and off times (Figs. 5a and 5b). Finally, in the last section we present an outlook for single-molecule enzymology.

4

Spectroscopic study of proteins

84%

Kierszniok K. , Dolibog P. , Pietrzyk B. , Pryzwan T.

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nr 78

324-329

PL

Białka są związkami wielkocząsteczkowymi zbudowanymi z aminokwasów połączonych wiązaniami peptydowymi. Stanowią podstawowy składnik strukturalny wszystkich żywych organizmów. Ich różnorodność ma związek z budową, a co za tym idzie ze sposobem uszeregowania reszt aminokwasów w cząsteczce. Albumina stanowi około 60% białek osocza, jej kształt determinuje sekwencja tworzących ją aminokwasów. Podstawowym aminokwasem wchodzącym w skład albuminy jest cysteina oraz w mniejszych ilościach glicyna, metionina i jedna reszta tryptofanowa, dzięki której wykazuje właściwości fluorescencyjne. Do badań strukturalnych białek stosowanych jest wiele metod fizycznych. Najczęściej wybierane są metody spektroskopowe, opierające się na generacji widm powstałych wskutek oddziaływania promieniowania elektromagnetycznego z materią. Najpowszechniej stosowaną metodą spektroskopii jest spektroskopia optyczna, wykorzystująca promieniowanie elektromagnetyczne od podczerwieni po ultrafiolet. Praca stanowi przegląd metod spektroskopowych wykorzystywanych w badaniach strukturalnych białek. Stanowi także wstęp do dalszych badań, które mają na celu wykorzystanie jednej z metod spektroskopowych do badań nad zmianami strukturalnymi albuminy po ekspozycji na czynniki fizykochemiczne. Opisane metody spektroskopowe cechują się różną czułością, specyficznością oraz procedurami, jakie należy wykonać podczas przygotowania próbki do badania. W spektroskopowym badaniu białek, ze szczególnym uwzględnieniem zmian zachodzących w ich strukturze, na uwagę zasługuje metoda spektroskopii fluorescencyjnej. Metoda ta jest niezwykle czuła i precyzyjna. Jest najlepszym wyborem do badania zmian strukturalnych białek, jakie zachodzą pod wpływem działania czynników fizykochemicznych. Nowoczesna aparatura pozwala na badanie zmian zachodzących w strukturze białek na poziomie molekularnym. Uchwycenie tych zmian i powiązanie ich z funkcjami białek wzbogaca wiedzę dotyczącą prawidłowości funkcjonowania organizmu, a także podłoża niektórych chorób.

EN

Proteins are macromolecular compounds made up of amino acids linked by peptide bonds. They are the basic structural component of all living organisms. Their diversity has to do with their structure, and therefore with the way the amino acid residues are arranged in the molecule. Albumin shape is determined by the sequence of amino acids that make it up. The primary amino acid in its composition is cysteine and in smaller amounts glycine, methionine and one tryptophan residue, thanks to which it exhibits fluorescent properties. For structural studies of proteins, many physical methods are used. The most commonly chosen are spectro-scopic methods, which deal with the interaction between electromagnetic radiation and matter. The article provides an overview of spectroscopic methods employed in the structural studies of proteins. It also serves as a prelude to further research that aims to utilise one of the spectroscopic methods to study the structural changes of albumin after exposure to physicochemical agents. The described spectroscopic methods are characterized by different sensitivity, specificity and procedures to be performed during sample preparation for the study. In the spectroscopic study of proteins, with particular attention to changes in their structure, the method of fluorescence spectroscopy deserves attention. It is the best choice for studying structural changes in proteins that occur under the influence of physicochemical factors. Capturing these changes and relating them to the functions of proteins enriches the knowledge of the normal functioning of the body, as well as the basis of some diseases.

5

Zjawisko generowania fal harmonicznych oraz jego wykorzystanie praktyczne ze szczególnym uwzględnieniem współczesnej ultrasonografii

84%

Jeka S. , Sokólska E. , Dura M. , Żuchowski P.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2011

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tom Vol. 17, nr 2

140-143

PL

Od wielu lat z postępem w dziedzinie fizyki związany jest postęp w naukach przyrodniczych. Jednym ze zjawisk, które odgrywa coraz większą rolę w naukach przyrodniczych, jest zjawisko generacji drugiej harmonicznej w ośrodkach anizotropowych. Możliwość uzyskania fali o podwojonej częstotliwości w stosunku do fali podstawowej pozwoliło na prowadzenie badań, wcześniej trudnych bądź niemożliwych do przeprowadzenia. Dzięki wyższej jakości obrazu badania ultrasonograficzne stały się bardziej czułe i są powszechnie wykorzystywane, m.in. w kardiologii, radiologii, chirurgii, reumatologii czy diagnostyce onkologicznej. Ultrasonografia staje się niezwykle cenioną metodą obrazowania obok rezonansu magnetycznego czy tomografii komputerowej. Ze względu na jej dostępność wiązane są z nią duże nadzieje na przyszłość.

EN

The progress in physics results in life sciences advancement. One of the phenomena, which plays more and more important role in life sciences, is the second harmonic generation in anisotropic materials. The possibility of achieving the wave, characterized by double frequency – with relation to the initial wave, allowed to conduct examinations, which were previously very difficult or impossible to perform. Thanks to higher quality of image, ultrasound examination has become more sensitive and is widely used, even in cardiology, radiology, surgery, rheumatology and oncology diagnostics. Ultrasonography with the use of tissue harmonic imaging is very valued method, so as magnetic resonance imaging or CT scan and due to its availability, high expectations are associated with it for the future.

6

Analiza struktury substancji humusowych gleb po wprowadzeniu węgla brunatnego na podstawie widm fluorescencyjnych

84%

Kwiatkowska-Malina J.

Inżynieria i Ochrona Środowiska

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2011

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tom T. 14, nr 3

197-208

PL

Badania dotyczyły analizy właściwości substancji humusowych (SH) oraz kształtowania struktury kwasów huminowych (KH) gleb po wprowadzeniu preparatu wytworzonego na bazie (85%) odpadowego węgla brunatnego. Do badań wykorzystano materiał glebowy z wieloletnich statycznych doświadczeń polowych i mikropoletkowych, a jako źródło materii organicznej Rekulter preparat wyprodukowany na bazie węgla brunatnego odpadowego i węgla brunatnego typu ziemistego z Zagłębia Konińskiego (KWB Konin). Niższe wartości intensywności fluorescencji na widmach 3-D EEM dla KH z gleby rdzawej (piaszczystej) wskazują na większy wpływ materii organicznej z węgla brunatnego na gleby bardzo lekkie piaszczyste w porównaniu do gleb cięższych (brunatna kwaśna, płowa). Wyniki ponad 20-letnich doświadczeń polowych na glebie rdzawej potwierdziły korzystne, długotrwałe oddziaływanie węgla brunatnego na właściwości gleby oraz na stan materii organicznej z tego źródła.

EN

Soil is non-renewable and a very complex natural resource which performs many vital functions: food (99%) and other biomass production, storage, filtration and transformation of many substances including water, carbon, nitrogen. Soil as a top layer of the earth's crust is the first receiver of anthropogenic contaminants, and may or may not serve as a natural barrier to protect groundwater against contamination from the surface. One of the most important indicators of soil quality is soil organic matter (SOM), which is an important building block for the soil structure, formation of stable aggregates, and is able to improve the infiltration rates and the storage capacity of water. SOM presents a major pool carbon in the biosphere and can act both as a source and sink for carbon dioxide and other greenhouse gases. Agricultural intensification and cultivation in general results in a serious decrease in SOM as compared to that in the natural vegetation. Presently, the protection of SOM is one of the main tasks in EU, because SOM in addition to its soil fertilizing function can act in the elimination of the soil contamination and carbon sequestration. In this context, humic substances (especially humic and fulvic acids) and cohesive fractions (clay, silt, silt clay, etc.) present in soil are favourable components. It is because of their high sorption capacity with respect to many contaminants, including heavy metals, which may results in their immobilisation and, consequently protect groundwater against contamination. Antropogenically transformed soils often do not contain humic substances (HS), thus their role as a natural barrier is decreased. Therefore, re-generation of HS through humification of organic matter from diverse sources added to soils, may be the way to re-built the protective character of soil barrier, and consequently to reduce environmental and/or health risks at areas under anthropopression. Transformation processes of brown coal applied to soil were described to evaluate the use of this material as an effective source of organic matter and HS generation in degraded soils. The goal of this study was to discuss fine brown coal derived preparation as effective sources of organic matter (and humic substances) especially in soils that are anthropogenically transformed. The research concerned the analysis of properties of HS as well as formations of humic acids (HAs) in soils after addition brown coal. Soil materials used in the research was collected from the long term field experiments and microplots, as the source of organic matter the Rekulter that is based (85%) on brown coal (soft smudge type) obtained from the Konin Basin deposits preparation was used. For qualitative characteristic of SOM, particularly, in HAs, modern analytical technique such as fluorescence intensity (FI) for 3-D EEM spectra was used. The lowest fluorescence intensity (FI) for 3-D EEM spectra were observed in the case of HAs extracted from rusty soil. The 20-years research results carried out on rusty soil (sandy) confirmed long-term effect of brown coal on soil properties as well as on organic matter that originated from this source.

7

Wyznaczanie map przeplywu szczelinowego w eksperymentalnych korytach zwirowych metoda spektroskopii fluorescencyjnej z zastosowaniem wegla aktywowanego

84%

Carling P. , Whitecombe L. , Radecki-Pawlik A. , Benson I. , Hankin B.

Zeszyty Naukowe Akademii Rolniczej w Krakowie. Inżynieria Środowiska

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2005

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tom 26

189-197

8

Instrumentalna ocena bieli wytworow papierowych

67%

Drzewinska E.

Przegląd Papierniczy

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2002

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tom 58

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nr 12

724-730

9

Czy możliwe jest określenie pochodzenia geograficznego miodu? Cz. 2

67%

Kania A.

Pasieka

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2015

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nr 3

10

Badania FTIR-ATR i fluorescencyjne układów białkowo-lipidowych

59%

Litwińczuk-Mammadova A. , Cieślik-Boczula K. , Rospenk M.

Wiadomości Chemiczne

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2017

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tom [Z] 71, 1-2

109--132

EN

Lipid-protein systems paly curtail roles in living systems [49]. Hence, a determination of their structure at different levels of organization is still one of the most important tasks in many research projects. A study of lipid-protein systems is based on many physicochemical techniques, such as spectroscopy of FTIR, Raman, fluorescence, NMR, EPR, as well as DLS, DSC and TEM methods. In the presented paper tow of the most frequently used methods, that is FTIR and fluorescence spectroscopy, will be discussed in details. They are characterized by a relatively low cost of sample preparation, a short measuring time, and they give a huge number of structural and physicochemical information about lipid-protein systems. In the FTIR-ATR spectroscopy many of vibrational bands are commonly used as very precise vibrational indicators of structural changes in lipids and proteins (Fig. 1) [1–6]. They allows to characterize lipid and protein components separately in mixed systems. Additionally, structural changes in lipid membranes can be monitored in one FTIR-ATR experiment simultaneously in a region of hydrophilic lipid head-groups (Fig. 5) [17, 18], in a hydrophobic part composed of hydrocarbon lipid chains (see Figures 2 and 3) [7–9], and in a lipid membrane interface represented by ester lipid groups (Fig. 4) [4, 6, 11, 12]. A secondary structure of proteins and peptides in different experimental conditions can be defined in the FTIR-ATR spectroscopy on the base of amide I bands (Fig. 6 and Tabs 1, 2 and 3) [20–22]. A fluorescence spectroscopy is a complementary methods to FTIR spectroscopy in a study of lipid-protein systems. It competes information about time-dependent and very fast (in a scale of femtoseconds) structural processes in both lipids [41–45] and proteins [23, 27, 48]. The folding, denaturation, and aggregation of proteins and lipid membranes accompanied by changes in an order, packing and hydration of the system under study [23, 27, 41–45, 48].

11

Historia atomowej analizy spektralnej. Cz. III. Rozwój analizy ilościowej

59%

Godlewska-Żyłkiewicz B.

Analityka : nauka i praktyka

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2007

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tom nr 4

36-38