70 research outputs found
A microscopic surface-enhanced Raman study of a single adsorbate-covered colloidal silver aggregate
No full textA novel atmospheric pressure glow discharge system for sensitive determination of As, Sb, and Se by optical emission spectrometry following their hydride generation
No full textMetadata and measurement data related to the publication entitled "A novel atmospheric pressure glow discharge system for sensitive determination of As, Sb, and Se by optical emission spectrometry following their hydride generation", which was published by K. Greda, J. Kratzer, N. Vlckova and P. Pohl in Spectrochimica Acta Part B, 2024, volume 213, number 106879</p
Cutis Laxa and Excessive Bone Growth due to de novo mutations in PTDSS1
Get PDFThe cutis laxa syndromes are multisystem disorders that share loose redundant inelastic and wrinkled skin as a common hallmark clinical feature. The underlying molecular defects are heterogeneous and 13 different genes have been involved until now, all of them being implicated in elastic fiber assembly. We provide here molecular and clinical characterization of three unrelated patients with a very rare phenotype associating cutis laxa, facial dysmorphism, severe growth retardation, hyperostotic skeletal dysplasia and intellectual disability. This disorder called Lenz-Majewski syndrome (LMS) is associated with gain of function mutations in PTDSS1, encoding an enzyme involved in phospholipid biosynthesis. This report illustrates that LMS is an unequivocal cutis laxa syndrome and expands the clinical and molecular spectrum of this group of disorders. In the neonatal period, brachydactyly and facial dysmorphism are two early distinctive signs, later followed by intellectual disability and hyperostotic skeletal dysplasia with severe dwarfism allowing differentiation of this condition from other cutis laxa phenotypes. Further studies are needed to understand the link between PTDSS1 and extra cellular matrix assembly
Generation of metal nanoparticles in the presence of oligoproline derivatives
Get PDFThe generation of metal nanoparticles has raised tremendous interest in recent years. They offer a huge variety of possible applications, due to their unique properties which strongly depend on their morphology. The controlled formation of nanoparticles of desired, monodisperse sizes and shapes still remains a challenge.
Herein we present the design and investigation of novel peptidic additives in the formation of different metal nanoparticles. Oligoprolines in different lengths were functionalized with guanidine, imidazole, primary amine, carboxylic acid, indole and pyrrolidinyl groups on the backbone. All of the peptides adopt the well-defined polyproline type II (PPII) helix which was not disturbed by the functionalization on the backbone. The formation reaction was carried out with and without an external reducing agent.
The additives were first investigated in the formation reaction of silver nanoparticles (AgNPs). The peptides bearing guanidine and imidazole groups were able to stabilize monodisperse and spherical nanoparticles using an external reducing agent in different sizes. Applying the additives without external reducing agents led in the case of guanidine- and indole-functionalized peptides also to the formation of monodisperse and spherical AgNPs.
In the presence of amine-functionalized peptides using ascorbic acid as external reducing agents non-spherical shapes were obtained and with pyrrolidinyl-functionalized peptides rods formed, next to spherical nanoparticles.
It was found that not only the functional group that was attached, but also the defined secondary structure was necessary for the peptides to act as additive in the formation reaction to stabilize nanoparticles in defined sizes and shapes.
In the formation of gold nanoparticles (AuNPs), guanidine- and imidazole-functionalized peptides were able to act as additives resulting in monodisperse nanoparticles when an external reducing agent was used. In contrast to the investigations for the formation of AgNPs also with amine-functionalized peptides monodisperse AuNPs were obtained. Without external reducing agent only polydisperse AuNPs were formed.
In the attempt to test the variability of the designed additives, first tests, evaluating the imidazole-functionalized peptides in the formation of platinum nanoparticles (PtNPs) was carried out. This resulted as well in monodisperse nanoparticles.
Furthermore a novel additive was designed inspired by a tripeptide, indentified in studies earlier carried out in our group. Using this peptide bearing two different functional groups it was possible to use it as additive in the formation of AgNPs using weak and strong reducing agents as well as visible light.
These results demonstrate the potential of these peptidic additives in the formation of metal nanoparticles in defined sizes and shapes
NanoTiO2 Sunscreen Does Not Prevent Systemic Oxidative Stress Caused by UV Radiation and a Minor Amount of NanoTiO2 is Absorbed in Humans
Get PDFThe present pilot study tested the efficiency of nanoTiO2 sunscreen to prevent the oxidative stress/inflammation caused by ultraviolet (UV) radiation using biomarkers in subjects’ blood, urine, and exhaled breath condensate (EBC). In addition, the skin absorption of nanoTiO2 was studied. Six identical subjects participated in three tests: (A) nanoTiO2 sunscreen, (B) UV radiation, and (C) sunscreen + UV. The first samples were collected before the test and the second after sunscreen application and/or UV exposure. On day 4, the third samples were collected, and the sunscreen was washed off, and the fourth samples were collected on day 11. The following biomarkers were measured: malondialdehyde, 4-hydroxy-trans-hexenal, 4-hydroxy-trans-nonenal, aldehydes C6-C12, 8-iso-Prostaglandin F2α, o-tyrosine, 3-chlorotyrosine, 3-nitrotyrosine, 8-hydroxy-2-deoxyguanosine, 8-hydroxyguanosine, 5-hydroxymethyl uracil, and leukotrienes, using liquid chromatography-electrospray ionisation-tandem mass spectrometry. Titania was measured using inductively coupled plasma mass spectrometry and TiO2 nanoparticles by transmission and scanning electron microscopy. Sunscreen alone did not elevate the markers, but UV increased the biomarkers in the plasma, urine, and EBC. The sunscreen prevented skin redness, however it did not inhibit the elevation of oxidative stress/inflammatory markers. Titania and nanoTiO2 particles were found in the plasma and urine (but not in the EBC) in all sunscreen users, suggesting their skin absorption
Bilaterale Untersuchungen und Modellgestutzte Prognosen von Huminstoffeintragen in Oberflachengewasser Aufgrund Veranderter Okosystemzustande und Deren Relevanz fur die Trinkwasserproduktion.
No full textAvailable from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi
Bilaterale Untersuchungen und Modellgestutzte Prognosen von Huminstoffeintragen in Oberflachengewasser Aufgrund Veranderter Okosystemzustande und Deren Relevanz fur die Trinkwasserproduktion.
No full textAvailable from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi
Surface-enhanced Raman scattering and surface-enhanced resonance Raman scattering excitation profiles of Ag-2,2¿-bipyridine surface complexes and of [Ru(bpy)3]2+ on Ag colloidal surfaces: manifestations of the charge-transfer resonance contributions to the overall surface enhancement of Raman scattering.
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