—The paper discusses the spatial distribution of the main parameters of primary production in the Bransfield Strait in the austral summer. The integrated primary production in the strait varied from ...435 to 741 mgC m
–2
day
–1
. The share of primary production in the total production of phyto- and bacterioplankton in the upper 10 m layer was 82–91%. Potential photosynthetic capacity (F
v
/F
m
) was high within the euphotic layer (0.418–0.749) throughout the area. The production parameters in the two main water masses in the strait did not differ. Photosynthetic efficiency (the ratio of the assimilation number and the relative electron transport rate, AN/rETR) varied in different subregions of the study area by almost six times.
Convenient preparation of fluorogenic hairpin DNA probes (molecular beacons) carrying a pair of FAM fluorophores (located close to 5'-terminus of the probe) or a pair of BHQ1 quenchers on 3'-terminus ...(with (BHQ1)2 or BHQ1-BHQ1 composition) is reported. These probes were used for the first time in a real-time PCR assay and showed considerable improvements in fluorogenic properties (the total fluorescence increase or signal-to-background ratio) in assay conditions vs. conventional one-FAM-one-BHQ1 molecular beacon probes as well as vs. hydrolyzable one-FAM-one-BHQ1 TaqMan probes. At the same time, such multiple modifications of the probe do not influence its Cq (a fractional PCR cycle used for quantification). The probe MB14 containing a BHQ1-BHQ1 pair showed a PCR fluorescence/background value of 9.6 which is more than two times higher than that of a regular probe MB2 (4.6). This study demonstrates prospects for the design of highly fluorogenic molecular beacon probes suitable for quantitative real-time PCR and for other potential applications (e.g. intracellular RNA detection and SNP/mutation analysis).
Molecular beacons carrying JOE dye (4′,5′-dichloro-2′,7′-dimethoxy-6-carboxyfluorescein) on a rigid or flexible linker and one or two BHQ1 quenchers have been prepared and tested in real-time PCR ...using Fusarium avenaceum elongation factor 1α DNA template. The probes were different in their structures (loop size and stem length), linkers for dye attachment (6-aminohexanol or trans-4-aminocyclohexanol), quencher composition (single and double BHQ1) to elucidate the influence of all these features. Fluorogenic properties of the probes were studied and compared to those of FAM (fluorescein)-based probes. All the factors – stem length, JOE vs FAM, rigid vs flexible linker, single vs double quencher – appeared to play a considerable role in the probe's fluorescent properties and determine the usability of the probe at two different temperatures of fluorescence detection (55°С and 64°С).
•A series of Molecular beacons with different structure carried JOE was tested in qPCR.•JOE proved to be brighter than FAM with probes with the same sequence.•The length of MB's stem was varied from 4 to 8 bp to optimize MBs design.•A rigid linker for JOE attaching is preferable for increasing light-up of fluorescence.•The second BHQ1 in probe significantly decrease background of fluorescence.
Silver alloys with tellurium, selenium and sulphur fulfil the conditions for the internal oxidation. Microstructure of these alloys consists of matrix (dilute solid solution) and particles of ...intermetallic compounds. Internal oxidation of ternary alloys is very similar to that of the binary alloys, but there are also distinctions in thermodynamics properties of alloying elements. At the direct oxidation of the particles of the intermetallic compound the phenomena of the selective oxidation was observed. Concentration of more reactive elements is increasing in the oxidized part of the particles of the intermetallic compound (Te in AgTeSe alloys). Therefore the precipitated oxides formed with diffusional internal oxidation are richer with less reactive alloying element (Se in AgTeSe alloy). In the precipitated oxide particles the concentration of selenium is more than twice higher than of tellurium.
The synthesis of phosphoramidite reagents and solid-phase supports based on hydroxyprolinol for the introduction of the residues of biotin, lipoic acid, amino groups, and terminal acetylene groups at ...different positions of the oligonucleotide chain has been described. The efficiency of the reagents and supports has been confirmed by the synthesis of the corresponding modified oligonucleotides.
The purpose of our investigation was to perform the thermodynamic calculation of all possible reactions in the Cu-Se-O system and to explain the oxidation mechanism in various conditions. For such ...study, a model of copper with one single inclusion and alloy with 1.65 wt. % Se were made. Depending on time, the oxidation has been taking place at two different temperatures and two oxygen partial pressures. The oxidized samples have been investigated by DTA, optical and electron microscopy (SEM).
The article discusses the morphology, microstructure and chemical composition of the boundary layer in explosive welding of low-carbon steel and tantalum plates. Pools of melt composed of both metals ...and having a heterogeneous chemical composition appear on the boundary layer. This phenomenon is the result of incomplete mixing of both: molten metals due to rapid cooling and solidification. Within the pools of alloy, a large number of non-metallic oxide inclusions, products of deoxidation of molten alloys, can be found. The non-metal inclusions are round (0.1 to 2 mu m in diameter) and vary in both: size and chemical composition. The main component of the non-metal inclusions is Ta sub 2 O sub 5 , which also contains iron, manganese, and aluminium oxides. The number of non-metal inclusions is unusually high for low-carbon steel and comparable to the number of non-metal inclusions in welds. Oxygen which causes the large number of deoxidised products does not originate in the low-carbon steel, as this steel is relatively clean. The most probable source of oxygen is the oxide scale from the surface of the low-carbon steel, which was poorly cleaned prior to welding.
Pentafluorophenyl esters of 5- and 6-carboxyfluorescein-3‘,6‘-O-dipivalate can be easily separated in multigram quantities by column chromatography. The individual isomers were converted into stable ...phosphoramidites suitable for oligonucleotide synthesis. The use of the cyclohexylcarbonyl (Chc) protecting group instead of pivaloyl (Piv) facilitates the separation of isomers. The fluorescence spectra of 5- and 6-carboxyfluoresceins on oligonucleotides were compared.
Mechanism of the oxidation of the thermal-resistant Fe-C-Si-Al-Zr alloys was investigated at high temperatures. For the analysis three series samples: L1, L2 and L3, had been annealed at 1100 deg C, ...were cast. After annealing the samples were investigated on the oxide thickness increase. They were observed and analysed by optical and electron microscopes. In case of the small zirconium content in the L1 sample, the graphite lamellae and only a significant amount of zirconium carbide in the ferrite matrix have been observed. At higher zirconium content (the L2 and L3 samples) graphite lamellae and particles of ZrC have been observed. During annealing an oxidation of graphite and ZrC took place. The oxidation of ZrC into ZrO sub 2 is direct and progressive. Evolving CO gas formed the pores around ZrO sub 2 . Under sufficient amount of the dissolved oxygen the oxidation of aluminium was taking place too. Al sub 2 O sub 3 was precipitating in the CO-ferrite interface filling up the formed pores. Finally the interaction between ZrO sub 2 and Al sub 2 O sub 3 were taking place and formation the compound of ZrO sub 2 Al sub 2 O sub 3 retarded further oxidation.
