scholarly journals Zinc(II) and copper(II) complexes with pheophytin and mesoporphyrin and their stability to UV-B irradiation: Vis spectroscopy studies

2012 ◽  
Vol 77 (2) ◽  
pp. 187-199 ◽  
Author(s):  
Jelena Zvezdanovic ◽  
Dejan Markovic ◽  
Sanja Milenkovic
Keyword(s):  
Heavy Metal ◽  
The Other ◽  
First Order ◽  
Absorbance Spectroscopy ◽  
First Order Kinetics ◽  
Porphyrin Derivatives ◽  
Vis Spectroscopy ◽  
Photochemical Decomposition ◽  
Spectroscopy Studies ◽  
The One

Stability of Zn(II) and Cu(II) complexes of porphyrin derivatives (pheophytin and mesoporphyrin) to UV-B -irradiation has been studied by absorbance spectroscopy in 95% ethanol. The chosen porphyrins as well as their heavy metal complexes undergo photochemical decomposition obeying first-order kinetics. In general, pheophytin is more stable than mesoporphyrin to UV-B irradiation. On the other hand, stability of Zn(II)-complex is smaller than Cu(II)-complex both for pheophytin and mesoporphyrin; however while Cu(II)-complex with pheophytin is more stable than the one with mesoporphyrin, with Zn(II)-complex the situation is vice versa.

Photocatalytic Efficiency for Dye Decolorization of the UV/TiO2, UV/TiO2 + In2O3 and UV/TiO2-In2O3 Systems

2013 ◽  
Vol 831 ◽  
pp. 263-266
Author(s):  
Chung Hsin Wu ◽  
Chao Yin Kuo ◽  
Chih Hao Lai ◽  
Wei Yang Chung
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Dye Decolorization ◽  
X Ray Diffraction ◽  
First Order ◽  
First Order Kinetics ◽  
Vis Spectroscopy ◽  
Reactive Red 2

This study explored the decolorization of C.I. Reactive Red 2 (RR2) by the ultraviolet (UV)/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems. The TiO2-In2O3 was generated by the sol-gel method and TiO2 + In2O3 was created by mixing TiO2 and In2O3 powders. The surface properties of TiO2, In2O3, and TiO2-In2O3 were analyzed by X-ray diffraction, a specific surface area analyzer, UV-vis spectroscopy, and scanning electron microscopy. The specific surface area of TiO2, In2O3, and TiO2-In2O3 was 29.5, 44.6, and 35.7 m2/g, respectively; additionally, the band gap of TiO2, In2O3, and TiO2-In2O3 was 2.95, 2.64, and 2.91 eV; respectively. The decolorization rate constant fit pseudo-first-order kinetics and that of the UV/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems was 0.0023, 0.0031, and 0.0072 min-1; respectively.

scholarly journals FORMATION OF A HEMOLYTICALLY ACTIVE CELLULAR INTERMEDIATE BY THE INTERACTION BETWEEN PROPERDIN FACTORS B AND D AND THE ACTIVATED THIRD COMPONENT OF COMPLEMENT

1973 ◽  
Vol 138 (6) ◽  
pp. 1305-1313 ◽  
Author(s):  
Douglas T. Fearon ◽  
K. Frank Austen ◽  
Shaun Ruddy
Keyword(s):  
Complement System ◽  
Probable Mechanism ◽  
Factor B ◽  
Molecular Sequence ◽  
First Order ◽  
First Order Kinetics ◽  
The One ◽  
Terminal Complement ◽  
Classical Complement ◽  
Third Component Of Complement

The present studies demonstrate that the factor B-dependent C3 convertase can be affixed to an erythrocyte by use of an intermediate bearing C3b and that this convertase brings the hemolytic reaction to completion with an efficiency comparable to that of classical convertase. The evidence that the EAC43 intermediate was lysed by a new pathway includes requirements for factors B and D and cell-bound C3b for subsequent lysis by the terminal components, C3-C9. The linear stoichiometry of the effective molecule titrations of C3b and factor B, and the first-order kinetics displayed by the generation and decay of the factor B-dependent hemolytic site are characteristics consistent with the one-hit theory as initially developed for the classical complement system. The use of hemolytically active cellular intermediates to examine the reactions occurring with C3b and factors B and D has allowed extension of the one-hit theory to this molecular sequence, development of effective molecule titrations, recognition of the analogies to the functional characteristics of the classical C3 convertase, and discrimination of the probable mechanism of terminal complement activation from reactive lysis.

Thermal reactions of mesityl oxide

1971 ◽  
Vol 24 (5) ◽  
pp. 955 ◽  
Author(s):  
NJ Daly ◽  
MF Gilligan
Keyword(s):  
Carbon Monoxide ◽  
Methyl Bromide ◽  
Hydrogen Bromide ◽  
The Other ◽  
Mesityl Oxide ◽  
Thermal Reactions ◽  
First Order ◽  
First Order Kinetics

Mesityl oxide (4-methylpent-3-en-2-one) thermally decomposes in the range 412-490� give methylbutenes, carbon monoxide, isobutene, and methane as major products. The initial 20% of reaction follows first- order kinetics and is described by the equation k1 = 1014.22exp(-63240/RT) s-1. A Rice-Herzfeld chain is proposed. Addition of hydrogen bromide leads to two reactions, one producing isobutene, carbon monoxide, and methyl bromide, and the other leading to polymerization. Likely steps in the polymerization are proposed.

FIRST ORDER PHASE TRANSITIONS, WHEN AND FROM WHERE DO THEY EMERGE? —THE CASE OF GELS

1995 ◽  
Vol 09 (07) ◽  
pp. 737-749 ◽  
Author(s):  
KEN SEKIMOTO
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Transition Point ◽  
The Other ◽  
Basic Fact ◽  
Theoretical Understanding ◽  
First Order ◽  
First Order Phase Transition ◽  
The One ◽  
First Order Phase

We briefly review the recent theoretical understanding of the first order phase transition undergone by gels with an emphasis on physical concepts, deliberately excluding details of modeling and analytic methods. The density of a gel changes discontinuously at the transition point. A variety of features of the transition result from the basic fact that the inhomogeneity of the density of the gel inevitably causes shear deformation. This deformation, on the one hand, reflects the geometry of the sample and, on the other hand, may alter the transition temperature.

The power of locality domains in phonology

Phonology ◽  
2017 ◽  
Vol 34 (2) ◽  
pp. 385-405 ◽  
Author(s):  
Thomas Graf
Keyword(s):  
Computational Complexity ◽  
The Other ◽  
Adequate Model ◽  
First Order ◽  
Other Hand ◽  
Integral Role ◽  
Domain Restrictions ◽  
The One

Domains play an integral role in linguistic theories. This paper combines locality domains with current models of the computational complexity of phonology. The first result is that if a specific formalism – strictly piecewise grammars – is supplemented with a mechanism to enforce first-order definable domain restrictions, its power increases so much that it subsumes almost the full hierarchy of subregular languages. However, if domain restrictions are based on linguistically natural intervals, we instead obtain an empirically more adequate model. On the one hand, this model subsumes only those subregular classes that have been argued to be relevant for phonotactic generalisations. On the other hand, it excludes unnatural generalisations that involve counting or elaborate conditionals. It is also shown that strictly piecewise grammars with interval-based domains are theoretically learnable, unlike those with arbitrary, first-order domains.

scholarly journals Quantitative analysis of proton-linked transport system. β-Galactoside exit in Escherichia coli

1980 ◽  
Vol 188 (2) ◽  
pp. 467-473 ◽  
Author(s):  
I R Booth ◽  
W A Hamilton
Keyword(s):  
Escherichia Coli ◽  
Quantitative Analysis ◽  
Transport System ◽  
Rate Constants ◽  
The Other ◽  
First Order ◽  
First Order Kinetics ◽  
Solute Accumulation ◽  
External Ph

The exit of lactose and thiomethyl-beta-D-galactoside from Escherichia coli ML308-225 has been studied to determine the role of carrier-dependent (zero-trans efflux) and carrier-independent (leak) processes. On the basis of its sensitivity to p-chloromercuribenzene sulphonate the exit of lactose was found to be almost wholly mediated by the carrier. Consistent with this conclusion was the finding that the rate of exit of this sugar was dependent on the external pH, being considerably slower at acid pH. On the other hand exit of thiomethyl-beta-D-galactoside was found to be composed of both carrier-dependent and carrier-independent processes. Both processes exhibited first-order kinetics with the rate constants for zero-trans efflux and leak being 0.137 min-1 and 0.079 min-1, respectively. The relevance of these findings for out earlier proposal for the methods of attenuation of solute accumulation is discussed [Booth, Mitchell & Hamilton (1979) Biochem. J. 182, 687–696].

A direct proof of the Feferman-Vaught theorem and other preservation theorems in products

1991 ◽  
Vol 56 (2) ◽  
pp. 632-636 ◽  
Author(s):  
Yiannis Vourtsanis
Keyword(s):  
Direct Proof ◽  
The Other ◽  
Direct Products ◽  
First Order ◽  
New Methods ◽  
Preservation Theorems ◽  
Order Language ◽  
Reduced Products ◽  
The One ◽  
By Products

Here we give short and direct proofs of the Feferman-Vaught theorem and other preservation theorems in products of structures. In 1952, Mostowski [5] first showed the preservation of ≡ωω by direct powers of structures. Subsequently, in 1959, Feferman and Vaught [2] proved the preservation of ≡ωω by arbitrary direct products and also by reduced products with respect to cofinite filters. In 1962, Frayne, Morel and Scott [3] noticed that the results extend to arbitrary reduced products. In 1970, Barwise and Eklof [1] showed the preservation of ≡∞λ by products and in 1971 Malitz [4] showed the preservation of ≡κλ with κ strongly inaccessible (or ∞) by products. Below, we give short proofs of the above results. The ideas used here have initiated, in [7], [8], [9], [10], [11], the introduction of several new methods in the theory of products, which on the one hand give new, direct proofs of the known results in the area, including generalizations or strengthenings of some of those, and, on the other hand, give several new results as well in the theory of products and related areas.Below, L denotes a (first order) language, and by a structure we mean an L-structure. 0 and 1 denote the logically valid and false sentence, respectively. We may write ā ∈ A for ā ∈ An for some n. Also, the values 1 and 2 of a parameter l in the definitions below express a duality corresponding to disjunctive and conjunctive forms.

Reflections on the concept of symmetry

2005 ◽  
Vol 13 (S2) ◽  
pp. 3-11 ◽  
Author(s):  
KUNO LORENZ
Keyword(s):  
Binary Relation ◽  
Second Order ◽  
The Other ◽  
First Order ◽  
Broken Symmetries ◽  
Other Hand ◽  
Logical Notion ◽  
The One ◽  
Ancient Usage

The concept of symmetry is omnipresent, although originally, in Greek antiquity, distinctly different from the modern logical notion. In logic a binary relation R is called symmetric if xRy implies yRx. In Greek, ‘being symmetric’ in general usage is synonymous with ‘being harmonious’, and in technical usage, as in Euclid's Elements, it is synonymous with ‘commensurable’. Due to the second meaning, which is close to the etymology of συ´μμετρoς, ‘with measure’ has likewise to be read as ‘being [in] rational [ratios]’ and displays the origin of the concept of rationality of establishing a proportion. Heraclitus can be read as a master of such connections. Exercising rationality is a case of simultaneously finding and inventing symmetries. On that basis a proposal is made of how to relate the modern logical notion of symmetry, a second-order concept, on the one hand with modern first-order usages of the term symmetric in geometry and other fields, and on the other hand with the notion of balance that derives from the ancient usage of symmetric. It is argued that symmetries as states of balance exist only in theory, in practice they function as norms vis-à-vis broken symmetries.

scholarly journals Silver Nanoparticles Decorated with PEGylated Porphyrins as Potential Theranostic and Sensing Agents

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2764
Author(s):  
Angelo Nicosia ◽  
Antonio Abbadessa ◽  
Fabiana Vento ◽  
Antonino Mazzaglia ◽  
Placido Giuseppe Mineo
Keyword(s):  
Silver Nanoparticles ◽  
Thermal Analyses ◽  
Ph Sensor ◽  
Spectroscopic Properties ◽  
The Other ◽  
Porphyrin Derivatives ◽  
Vis Spectroscopy ◽  
Range Alignment ◽  
Biomedical Field ◽  
Biological Environment

Silver nanoparticles (AgNPs) stand out over other metal nanoparticles thanks to their peculiar bactericidal and spectroscopic properties. Tunability of the AgNPs chemical–physical properties could be provided through their organic covalent coating. On the other hand, PEGylated porphyrin derivatives are versatile heteromacrocycles investigated for uses in the biomedical field as cytotoxic and tracking agents, but also as sensors. In this work, an easy multi-step approach was employed to produce coated silver nanoparticles. Specifically, the AgNPs were functionalized with 5,10,15-[p-(ω-methoxy-polyethyleneoxy)phenyl]-20-(p-hydroxyphenyl)-porphyrin (P(PEG350)3), using chloropropanethiol as a coupling agent. The P(PEG350)3 was structurally characterized through MALDI-TOF mass spectrometry, NMR spectroscopy and thermal analyses. The functionalization of AgNPs was monitored step-by-step employing UV-Vis spectroscopy, dynamic light scattering and thermogravimetric techniques. HRTEM and STEM measurements were used to investigate the morphology and the composition of the resulting nanostructured system (AgNP@P(PEG350)3), observing a long-range alignment of the outer porphyrin layer. The AgNP@P(PEG350)3 combines the features of the P(PEG350)3 with those of AgNPs, producing a potential multifunctional theranostic tool. The nanosystem revealed itself suitable as a removable pH sensor in aqueous solutions and potentially feasible for biological environment applications.

scholarly journals Food – The Story of Our Life: A Contribution to the Studies of Food and the Anthropology of Taste

2016 ◽  
Vol 8 (1) ◽  
pp. 41
Author(s):  
Gordana Đerić
Keyword(s):  
Food Consumption ◽  
Food Studies ◽  
The Other ◽  
Art Theory ◽  
First Order ◽  
Basic Issue ◽  
History Of ◽  
The One ◽  
Taste And Smell ◽  
Philosophy Of Food

By approaching the phenomenon of food (consumption) as an identity issue of the first order, as man’s alimentary, only true biography, and an authentic expression of self and experience, but also as a key phenomenon in the development of man and mankind, the author points toward the anthropologically relevant aspects of research pertaining to food (the mythological, cultural and historical, economic, aesthetic, linguistic, political). The development of the art and philosophy of food (consumption) is considered in the context of history of the ideas of Epicureanism, empiricism and lametrism, as well as in the context of the end of the cult of culture” in its traditional meaning. Moving between issues of art theory and epistemology, the author pays special attention to the causes of the theoretical neglect of the senses of taste and smell, historical reasons of the second-rate position of gastronomy among the other sciences and arts, as well as changes taking place at the end of the “short 20th century” which enabled a revolution in aesthetics and social values – the expansion of food studies and the art of cookery. Thus the aim of the paper is twofold: on the one hand it is an attempt to shed some light on the history of this revolution in the context of the theoretical and aesthetic relationship toward food and the art of its preparation, and on the other, it should be an argument incentive to have the basic issue of food (consumption) find its way onto our own academic menu.

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