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1
Content available The energy consumption during the birch tree sap concentration process using the reverse osmosis system
Wawer J., Bilek M., Sosnowski S.
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
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2018
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Vol. 7, No 1
151--155
EN
Birch tree sap was concentrated by mens of the reversed osmosis technique. The energy consumption in a small-scale pilot apparatus was estimated. The threshold value for the water removal above which the specific energy consumption significantly increased was identified. Below the threshold value the reversed osmosis had low energy demand and could be an attractive method for the production of birch tree sap-based beverages.
2
Content available Anion alkoksyallenowy w syntezie związków naturalnych i ich analogów
Busiak B., Utecht G., Jasiński M.
Wiadomości Chemiczne
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2016
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[Z] 70, 1-2
3--23
EN
Among diverse systems containing multiple bonds, cumulenes are recognized as the most reactive derivatives towards both nucleophilic and electrophilic agents, and for this reason, they are considered as important class of substrates for organic synthesis. Over the last three decades alkoxyallenes have been demonstrated as highly useful C3-building blocks for the construction of numerous N-, O-, and S-containing heterocycles, including enantiomerically pure compounds. Special attention has been paid to lithiated alkoxyallenes as suitable nucleophiles for the reactions with alkyl halides, strained heterocycles, carbonyl compounds and their derivatives. The presence of the allene unit in the initially formed adducts opens up several possibilities in the preparation of more complex systems. In this review, selected applications of lithiated alkoxyallenes in the synthesis of natural products and their analogues are discussed.
3
Content available Aktywność biologiczna związków acetylenowych pochodzenia naturalnego
Kadela-Tomanek M., Chrobak E., Bębenek E., Lubczyńska A., Siudak S., Wójcik A., Otulakowska A.
Wiadomości Chemiczne
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2016
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[Z] 70, 9-10
613--632
EN
The natural acetylenic products containing at least one a carbon-carbon triple bond, are important class of compounds widely distributed in the environment. Development of spectroscopic techniques and methods for the isolation of metabolites allowed the extraction of natural acetylenic compounds. The most of these substances have been obtained from marine organisms, such as: cyanobacteria, algae and sponges. The next source of metabolites are herbal plants, which were used in the Chinese traditional medicine. A many of them show interesting biological activity. The first isolated natural compound possessing an acetylenic unit was dehydromatricaria ester, which was obtained from rhizome European goldenrod (Solidago virgaurea). To present day have been found and researched more than 2000 natural acetylenic metabolites. Due to the chemical structure, natural acetylenic compounds were divided into six groups: peptides, aromatic compounds, enediyne antibiotics, sterols, carotenoids, and poliacetylenic compounds . This article focuses natural acetylenic substances, which exhibit interesting biological properties, particularly anticancer ones. The review presents many of such metabolites, including fatty alcohols, ketones, acids, ethers, and carotenoids.
4
Content available Kultowe bestie : literatura a nauka
Wilk A. N., Kafarski P.
Wiadomości Chemiczne
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2014
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[Z] 68, 1-2
1--20
EN
Vampire, werewolf or zombie are individuals more and more often met in horrors. Since their existence seems to break down all rules of science literature experts consider them exclusively as metaphor of human anxiety towards unknown and incomprehensible and unexplored issues. Such a definition of these monsters is well acknowledged in literature and cinematography. However, this seems not to be fully true because there exist some rationales and some proofs that these mystic characters might be seen in reality.
5
Content available remote A simple proof of the classification theorem for positive natural products
Muraki N.
Probability and Mathematical Statistics
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2013
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Vol. 33, Fasc. 2
315--326
EN
A simplification of the proof of the classification theorem for natural notions of stochastic independence is given. This simplification is made possible after adding the positivity condition to the algebraic axioms for a (non-symmetric) universal product (i.e. a natural product). Indeed, this simplification is nothing but a simplification, under the positivity, of the proof of the claim that, for any natural product, the ‘wrong-ordered’ coefficients all vanish in the expansion form. The known proof of this claim involves a cumbersome process of solving a system of quadratic equations in 102 unknowns, but in our new proof under the positivity we can avoid such a process.
6
Content available Biblioteki związków chemicznych
Zwoliński K. M., Leśnikowski Z. J.
Wiadomości Chemiczne
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2012
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[Z] 66, 7-8
741-765
EN
Over the past decade one can observe a scientific revolution taking place resulting in an explosion of new biotechnologies. Moreover, with the end of the human genome project and following expansion of the extensive genetic research an unprecedented number of new biological targets useful in drug design have been identified. Simultaneously, new methods such as combinatorial synthesis have expanded the overall size of chemical libraries and high-throughtput technologies have enabled to screen more than one million compounds a day [43]. However, an increasing size of chemical libraries in a random fashion may not necessary increase a probability of success and the overall number of successfully identified leads. Thus, success of any drug discovery program depend heavily on the assumed selection criteria of appropriate molecules [58] which properties should maximize the chances of identifying ligands for any given target. Selection criteria used for compounds to generate diverse as well as focused chemical libraries are briefly discussed in the present overview. We describe the most important quality factors such as size, diversity and chemical tractability which should be always kept in mind during the design of chemical libraries. Chemical space is enormous and limited only by a chemist`s imagination. The number of possible drug-like molecules within chemical space has been estimated to be around 1060 [17]. In contrast the overall number of atoms in the observable Universe is approximately 1080. It is obvious that it is impossible to synthesize every possible molecule so one need to explore only those regions of chemical space which are enriched with molecules of appropriate structure and function. Recent strategies for the design of high-quality collections of structurally diverse sets of small molecules are discussed in the context of probing the chemical space in order to find new biologically active structures.
7
Content available Chemiczne markery miodów odmianowych
Jasicka-Misiak I., Kafarski P.
Wiadomości Chemiczne
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2011
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[Z] 65, 9-10
822-837
EN
Honey is a natural food product reach in variety of chemical compounds, which are responsible for its quality and aroma. Unifloral honeys are especially attractive for buyers and are quite frequently falsified. Thus, the assessment of their quality is indispensable. Today it relays on identification of the pollen and determination of honey physicochemical properties. In this paper the new methods for the assessment of honey quality are described. They relay on analysis and identification of volatile compounds typical for certain uniflolar honeys. These compounds are called markers. These could virtually all natural products with products of decomposition of phenylalanine, terpenes, flavonoids, aromatic acids, heterocycles, caretonoids and non-typical sugars. The second approach is to study metabolome of these honeys. The most effective metabolomic studies relay on building up “finger-prints” of certain honey branch basing on relative concentrations of chosen set of volatile compounds.
8
Content available remote Catalytic spectrophotometric determination of vanadium and its application to some natural and agricultural products
Feng Q.-L., Wen D.-Y.
Chemia Analityczna
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2006
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Vol. 51, No. 2
319-325
EN
A simple and highly sensitive spectrophotometric method for the determination ofvana-dium(V) has been proposed. The method is based on catalytic oxidation of 1,8-dihydroxy-naphthalene-3,6-disiulfonic acid and phenylhydra/.inc with potassium chlorate. The molar absorptivity was 7.8 x 106 at the wavelength of 506 nm, detection range was 0.2-5.0 ng mL-1. The new method is simple and provides high sensitivity and good selectivity. It has been successfully applied to the determination of trace amounts of vanadium in spring water, black bean, corn, tea leaves, and Rhodiola schalinensis A leaves.
PL
Opracowano prostą i czułą spektofotometryczną metodę oznaczania wanadu( V). Metoda polega na katalitycznym utlenianiu kwasu l,8-dihydroksynaftaleno-3,6-disuIfonowego i fenylohydrazyny za pomocą chloranu potasowego. Molowy współczynnik absorpcji przy długości fali 506 nm wynosił 7 x 106, a zakres stężeń w którym prowadzono pomiary 0.2—5,0 ng mL-1. Nowa metoda jest prosta, selektywna i bardzo czulą. Zastosowano ją z powodzeniem do oznaczania śladowych ilości wanadu w wodzie źródlanej, czarnej fasoli, kukurydzy, herbacie i liściach Rhodiola schalinensis A.
9
Content available remote Ekstrakcja produktów naturalnych gazami w stanie nadkrytycznym
Wolski T., Ludwiczuk A.
Przemysł Chemiczny
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2001
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T. 80, nr 7
286-289
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