Exceptional plutonium accumulation in glacier mice and cryoconite in Icelandic glaciers.

This study comprehensively surveys artificial (Cs, Am, Pu, Pu) and natural (Pb) radionuclides in Icelandic glacier mice and cryoconite. Samples were collected from five glaciers in Iceland - Fjallsjökull, Falljökull, Kvíárjökull, Skaftafellsjökull, and Sólheimajökull - with glacier mice found only at the first three sites. Radionuclide concentrations in both glacier mice and cryoconite were slightly higher than those previously reported in Iceland.

Wetting Properties of a Saponin-Rich Aqueous Soapwort Extract.

The saponin-rich plant extracts are mixtures of various surface-active and non-surface-active compound substances. Their exact composition depends on the type of plant and its part from which they were extracted. In this study, we analyze the wetting properties of the extract obtained by boiling soapwort ( L.

Zein Monolayers: Characterization and Interaction with (Bio)surfactants.

Zein is the main protein of corn seeds, which is often employed in food packaging and as a model of keratin. In this study, zein monolayers were deposited from nonconventional solvents: aqueous ethanol and acetic acid, on pure water that was later exchanged for 1% (bio)surfactant solutions: SDS, CTAB, Triton X-100, and the saponin-rich plant extracts of soapwort ( L.) and cowherb ( [P.

Variability of fallout radionuclide accumulation and possible contamination sources of a peripheral glacier in southeast Greenland.

Cryoconite, granule-shaped debris found on the surface of glaciers, is known for trapping substantial quantities of pollutants such as radioactive nuclides and heavy metals. This study investigates contamination levels, sources and spatial variability of natural and artificial radioisotopes in cryoconite from Mittivakkat Gletsjer in southeast Greenland by determining the activity and atomic ratios of selected radionuclides. The maximum activity concentrations of artificial radioisotopes were 1129 ± 34 Bq kg for Cs, 3.

Glacier mice as a temporary sink for fallout radionuclides and heavy metals on the Norwegian glacier Austerdalsbreen.

Glacier mice are peculiar rolling or stationary moss balls found on the surface of some glaciers. They may harbour an ecological habitat for cold-adapted invertebrates and microorganisms, but little is known about their potential to accumulate and disseminate harmful elements and substances. In this study, we investigate the presence of fallout radionuclides (Cs, Pu, Pu, Pu, Pb) and heavy metals (Pb, As, Hg, Cd) in glacier mice and compare the results to bryophytes from adjacent glacier ecosystems.

Surface activity of Lupinus angustifolius (blue lupine) seed extracts.

Surface tension (γ) of the seed extracts of four lupine cultivars showed values in the range 44.9-46.4 mN/m.

A new RPLC-ESI-MS method for the determination of eight vitamers of vitamin E.

Vitamin E consists of four (α-, β-, γ-, δ-) isoforms of tocopherols (T) and tocotrienols (T3), collectively known as tocols. Current LC methods for tocols suffer from either the poor ability to resolve the β- and γ- isoforms (RPLC), or require the use of nonpolar solvents (NPLC), which complicates subsequent MS/MS detection. Moreover, we show that coupling of UV with MS leads to tocols photodegradation.

Are all yeast biosurfactants really capable of lowering surface tension below 30 mN/m ?

The study discusses pitfalls in attempts to determine reliable surface tension values for the culture media and their extracts for two biosurfactant-producing yeast strains: Rhodotorula graminis and Rhodotorula babjevae. The values obtained from an Axisymmetric Drop Shape Analysis (ADSA) tensiometer showed systematically more and more shallow dynamic surface tension decays, suggesting a deterioration of their surface activity. The rate of this apparent surface activity loss was shown to depend on the sample history, with slower changes observed in vigorously shaken samples.

Toward an Electronic Tongue Based on Surfactant-Stabilized Chemosensory Microparticles with a Dual Detection Mode.

We propose a novel type of electronic tongue based on four types of monodispersed chemosensory microparticles (MPs) with a lipophilic core stabilized by a nonionic poloxamer surfactant. The lipophilic core composition was designed to achieve cross-sensitivity toward various ions and to enable spectrophotometric and/or spectrofluorimetric detection. Thus, generic anion-selective MPs, generic cation-selective MPs, as well as two types of metalloporphyrin-based MPs were fabricated and their morphology was characterized.

Surface tension of native and modified plant seed proteins.

The present review, dedicated to Prof. Zbigniew Adamczyk on the occasion of his 70th anniversary, covers the literature data on surface tension and surface compression (dilational) rheology of the adsorbed layers of 21 plant seed proteins (10 leguminous and 11 non-leguminous plants). They are typically analyzed as protein concentrates or isolates, the latter usually obtained by isoelectric precipitation or diafiltration.

Comparison of Precursor Preparation Routes on Final Density of YFeO Garnets Prepared via Reactive Sintering.

Yttrium iron garnet was obtained using four methods of synthesis. A modified citrate method and a modified citrate method with YIG (yttrium iron garnet, YFeO) nucleation were used. In two subsequent methods, YIP (yttrium iron perovskite, YFeO) and α-FeO obtained in the first case by the citrate method and in the second by precipitation of precursors with an ammonia solution were used as the input precursors for reaction sintering.

Soapwort ( L.) Extract vs. Synthetic Surfactants-Effect on Skin-Mimetic Models.

Our skin is continuously exposed to different amphiphilic substances capable of interaction with its lipids and proteins. We describe the effect of a saponin-rich soapwort extract and of four commonly employed synthetic surfactants: sodium lauryl sulfate (SLS), sodium laureth sulfate (SLES), ammonium lauryl sulfate (ALS), cocamidopropyl betaine (CAPB) on different human skin models. Two human skin cell lines were employed: normal keratinocytes (HaCaT) and human melanoma cells (A375).

Precursor ion approach for simultaneous determination of nonethoxylated and ethoxylated alkylsulfate surfactants.

We present a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of sodium lauryl sulfate and sodium laureth sulfate homologues in the range of alkyl chain length C-C with 0-5 ethoxy groups. The method is based on scanning the precursor ions fragmenting to m/z 80 and 97 (Precursor Ion Scanning mode), which makes it specific for species with easily cleavable sulfate groups. By monitoring fragmentation of thus discovered quasi-molecular ions we were able to unequivocally identify all sulfate species present in complex mixtures of alkyl and alkyl-ether sulfates with molecular weight ranging from 200 to 600 m/z.

Surface activity and foaming properties of saponin-rich plants extracts.

Saponins are amphiphilic glycosidic secondary metabolites produced by numerous plants. So far only few of them have been thoroughly analyzed and even less have found industrial applications as biosurfactants. In this contribution we screen 45 plants from different families, reported to be rich in saponins, for their surface activity and foaming properties.

Antimicrobial films of poly(2-aminoethyl methacrylate) and its copolymers doped with TiO and CaCO.

Polymeric coatings with positive surface charge offer potential antimicrobial activity, which they owe to a simple electrostatic attraction with negatively charged bacterial walls and membranes. We describe synthesis and characterization of poly(2-aminoethyl methacrylate) and its copolymers with methyl methacrylate and butyl acrylate, as potential binders for antimicrobial solvent-cast paints. TiO and CaCO mineral particles were employed as model pigments/fillers, as they are used in most real-life paint formulations.

Effect of synthetic surfactants and soapwort (Saponaria officinalis L.) extract on skin-mimetic model lipid monolayers.

The effect of a saponin-rich extract from rhizomes of Soapwort (Saponaria officinalis L) and four synthetic surfactants: sodium lauryl sulphate (SLS), sodium laureth sulphate (SLES), ammonium lauryl sulphate (ALS) and cocamidopropyl betaine (CAPB) on two model lipid monolayers is analyzed using surface pressure, surface dilatational rheology and fluorescence microscopy. The following monolayers were employed: dipalmitoylphosphatidylcholine/cholesterol mixture in a molar ratio of 7:3 (DPPC/CHOL) and Ceramide [AP]/stearic acid/cholesterol in a molar ratio of 14:14:10 (CER/SA/CHOL). They mimicked a general bilayer structure and an intercellular lipid mixture, respectively.

Effect of saponins from quinoa on a skin-mimetic lipid monolayer containing cholesterol.

The study discusses the effect of a quinoa seed coat extract on a cholesterol-based Langmuir monolayer mimicking the intercellular lipid mixture in the skin's outermost layer - stratum corneum. Besides cholesterol (CHOL), the monolayer contains also stearic acid (SA) and ceramide VI (CER), in a molar ratio of 10:14:14. Three quinoa extracts were tested for their surface activity: a) from the whole seed, b) from the dehulled seed, and c) from the seed coat.

Antimicrobial dispersions and films from positively charged styrene and acrylic copolymers.

Antimicrobial properties of methyl methacrylate - ethyl acrylate and styrene - ethyl acrylate copolymers, both as latexes and after film formation were tested. The polymers were synthesized using a cationic surfactant, cetytrimethylammonium bromide (CTAB) as an emulsifier, in presence of either a cationic or an anionic initiator. The resulting latex particles showed sizes between 50 and 320 nm (larger for the anionic initiator), and ζ-potential between +30 and +70 mV (more positive for the cationic initiator).

Effect of surfactants on surface activity and rheological properties of type I collagen at air/water interface.

We describe the effect of three synthetic surfactants (anionic - sodium dodecyl sulfate (SDS), cationic - cetyltrimethylammonium bromide (CTAB) and nonionic - Triton X-100 (TX-100)) on surface properties of the type I calf skin collagen at the air/water interface in acidic solutions (pH 1.8). The protein concentration was fixed at 5×10molL and the surfactant concentration was varied in the range 5×10molL-1×10molL, producing the protein/surfactant mixtures with molar ratios of 1:1, 1:2, 1:5, 1:10 and 1:20.

On the Interaction between Digitonin and Cholesterol in Langmuir Monolayers.

In this article, we describe the effect of a highly hemolytic saponin, digitonin, on model lipids cholesterol and dipalmitoylphosphatidylcholine (DPPC) using a combination of tensiometric (surface pressure and dilatational surface elasticity), spectroscopic (infrared reflection absorption spectroscopy, IRRAS), microscopic (fluorescence microscopy), and scattering techniques (neutron reflectivity, NR, and grazing incidence X-ray diffraction, GIXD). The monolayers of individual lipids and their 10:9 (mol/mol) mixture were exposed to an aqueous solution of digitonin (10(-4) M) by subphase exchange using a setup developed recently in our laboratory. The results confirm that digitonin can adsorb onto both bare and lipid-covered water-air interfaces.

Complexation of phospholipids and cholesterol by triterpenic saponins in bulk and in monolayers.

The interactions between three triterpene saponins: α-hederin, hederacoside C and ammonium glycyrrhizate with model lipids: cholesterol and dipalmitoylphosphatidylcholine (DPPC) are described. The oleanolic acid-type saponins (α-hederin and hederacoside C) were shown to form 1:1 complexes with lipids in bulk, characterized by stability constants in the range (4.0±0.

Comparison of the effect of two Quillaja bark saponin extracts on DPPC and DPPC/cholesterol Langmuir monolayers.

The present study aims at comparing the effect of two commercially available Quillaja bark saponin (QBS) products on model Langmuir monolayers. Pure dipalmitoylphosphatidylcholine (DPPC) and mixed DPPC/cholesterol Langmuir monolayers were used as crude models of erythrocyte membranes in order to better understand a hemolytic activity of QBS. Both QBS products are mixtures of several saponins and non-saponin fractions, only few of which can be assigned an exact chemical structure, as shown by an HPLC analysis.

Effect of enzymatic hydrolysis on surface activity and surface rheology of type I collagen.

We describe the adsorption behaviour and rheological properties of a calf skin type I collagen, and of its hydrolysates obtained using a Clostridium histolyticum collagenase (CHC) under moderate conditions (pH 7, 37°C). The effect of CHC concentration (2×10(-9)-2×10(-6)M) and incubation time (35-85min) was studied and optimised to achieve the highest decrease of surface tension and the highest dilational surface viscoelasticity of the adsorbed layers. SDS-PAGE electrophoresis and reverse-phase high performance liquid chromatography (RP-HPLC) were used to characterise the hydrolysis products.

Reverse hydrotropy by complex formation.

Self-aggregation of three di-N-alkylated diaza-18-crown-6 ethers (ACEs) was studied in non-polar solvents. The three ACEs differed by the length of the alkyl chain: n-decyl (ACE-10), n-hexadecyl (ACE-16) and n-tetracosane (ACE-24). From the previously reported interfacial tension isotherms, the formation of reverse micelles was expected above ACE concentrations of ∼10(-3) M.

Prevalence and correlation between TMD based on RDC/TMD diagnoses, oral parafunctions and psychoemotional stress in Polish university students.

The aim of the study was to assess the prevalence of temporomandibular disorders (TMD) and oral parafunctions, as well as their correlation with psychoemotional factors in Polish university students. The research was conducted in a group of 456 students (N = 456). The examination form comprised of two parts: survey and clinical examination.