Design Principles of Responsive Relaxometric F Contrast Agents: Evaluation from the Point of View of Relaxation Theory and Experimental Data.

F magnetic resonance imaging (MRI) is a promising tool in medical diagnostics. An important class of F MRI contrast agents is based on paramagnetic resonance enhancement. This effect allows an improvement in sensitivity by increasing the number of scans per unit of time or facilitates the development of responsive contrast agents that are based on changes in relaxation rates as a detection principle.

Hybrid, dual visible and near-infrared fluorescence emission of (6,5) single-walled carbon nanotubes modified with fluorescein through aryl diazonium salt chemistry.

The aryl diazonium salt chemistry offers enhancement of near-infrared (NIR) emission of single-walled carbon nanotubes (SWCNTs), although, the attachment of functional molecules which could bring hybrid properties through the process is underdeveloped. In this work, we utilize aryl diazonium salt of fluorescein to createdefects on (6,5) SWCNTs. We study the influence of pH on the grafting process identifying that pH 5-6 is necessary for a successful reaction.

Polyamine-Oligonucleotide Conjugates: 2'-Me-Triazole-Linked 1,4,7,10-Tetraazacyclododecane and Intercalating Dyes and Their Effect on the Thermal Stability of DNA Duplexes.

Oligonucleotides with the sequences 5'-GTG AUA TGC, 5'-GCA TAU CAC and 5'-GUG ATA UGC, where U is 2'--propargyl uridine, were subjected to post-synthetic Cu(I)-catalyzed azide-alkyne cycloaddition to attach 1,4,7,10-tetraazacyclododecane (cyclen) and two well-known DNA intercalating dyes: thioxanthone and 1,8-naphthalimide. We propose a convenient cyclen protection-deprotection strategy that allows efficient separation of the resulting polyamine-oligonucleotide conjugates from the starting materials by RP-HPLC to obtain high-purity products. In this paper, we present hitherto unknown macrocyclic polyamine-oligonucleotide conjugates and their hybridization properties reflected in the thermal stability of thirty-two DNA duplexes containing combinations of labeled strands, their unmodified complementary strands, and strands with single base pair mismatches.

Microplastics on sandy beaches of the southern Baltic Sea.

Microplastic occurrence and composition were investigated along the Polish coast (southern Baltic Sea) on 12 beaches differing in terms of intensity of their touristic exploitation, urbanisation and sediment characteristics. Their mean concentrations varied between 76 and 295 items per kg dry sediment. Fibres and plastic fragments were the dominant microplastic types.

SEC Separation of Polysaccharides Using Macroporous Spherical Silica Gel as a Stationary Phase.

Abstract: Meso- and macroporous spherical silica gels of pore sizes in the range of 60-1000 Å and 40-75 µm particle size were investigated as a stationary phase for the separation and purification of polysaccharides and poly(ethylene glycols) (PEGs) of various MWs using an aqueous mobile phase. Sephadex and Bio-Gel were used for comparison as the most common stationary phases for similar purposes. The separation of dextrans of a mean MW = 31 kDa from small molecules (NaCl) was possible with SiO with a pore size of 60-300 Å, but the observed efficiencies of a column of the same size were lower comparing with Sephadex or Bio-Gel.

Determination of silyl peroxides by ultra-performance liquid chromatography/electrospray ionisation mass spectrometry.

Rationale: Residual initiators in polymers are a concern in the case of products that come directly into contact with the human body or food. Due to low concentrations and difficulties in the sample preparation, highly sensitive and selective methods are required.

Methods: A series of bis-silyl- and alkyl-silyl peroxides were analysed by electrospray ionisation mass spectrometry (ESI-MS) on an ultra-performance liquid chromatography/time-of-flight (UPLC/TOF) instrument.

Marine litter on the seafloor of the southern Baltic.

Marine litter occurrence and composition were investigated during routine bottom trawl fish surveys type BITS performed in the Polish Maritime Areas (the southern Baltic Sea). Sampling covered a distance of 325km and an area of 16km at a depth range of 19-110m. Litter densities varying between 0 items/ha (34% of tows) and 2.

Phenology of cryptomonads and the CRY1 lineage in a coastal brackish lagoon (Vistula Lagoon, Baltic Sea).

Cryptomonadales have acquired their plastids by secondary endosymbiosis. A novel clade-CRY1-has been discovered at the base of the Cryptomonadales tree, but it remains unknown whether it contains plastids. Cryptomonadales are also an important component of phytoplankton assemblages.