12 research outputs found
Systematic approach in petroleum personnel competence assessment
The article is devoted to professional competence improvement of personnel in the petroleum industry. The technique for competence assessment optimization in oil and gas well drilling is developed. The specification for the oil and gas industry competence profiles has been provided
Systematic approach in petroleum personnel competence assessment
The article is devoted to professional competence improvement of personnel in the petroleum industry. The technique for competence assessment optimization in oil and gas well drilling is developed. The specification for the oil and gas industry competence profiles has been provided
Poly(Boc-acryloyl hydrazide): The importance of temperature and RAFT agent degradation on its preparation
Poly(acryloyl hydrazide) is a versatile polymer scaffold readily functionalised through post-polymerisation modification with aldehydes to yield polymers for biological applications. However, its polymerisation is affected by nucleophilic degradation of the RAFT agent that leads to early termination, an issue often overlooked in the polymerisation of primary acrylamides. Here we report the effect of temperature on the RAFT polymerisation of N’-(tert-butoxycarbonyl)acryloyl hydrazide (1) and demonstrate that by carefully selecting this polymerisation temperature, a balance between rate of polymerisation and rate of degradation of the RAFT agent can be achieved. This way a greater control over the polymerisation process is achieved, allowing the synthesis of Boc-protected poly(acryloyl hydrazide) with higher degrees of polymerisation than those achieved previously, while still maintaining low dispersities. We believe our results should be of importance to those working on the RAFT polymerization of primary and secondary (meth)acrylamides and monomers with nucleophilic moieties. </p
Collection of Analytes from Microneedle Patches
Clinical medicine and public health
would benefit from simplified
acquisition of biological samples from patients that can be easily
obtained at point of care, in the field, and by patients themselves.
Microneedle patches are designed to serve this need by collecting
dermal interstitial fluid containing biomarkers without the dangers,
pain, or expertise needed to collect blood. This study presents novel
methods to collect biomarker analytes from microneedle patches for
analysis by integration into conventional analytical laboratory microtubes
and microplates. Microneedle patches were made out of cross-linked
hydrogel composed of poly(methyl vinyl ether-<i>alt</i>-maleic
acid) and poly(ethylene glycol) prepared by micromolding. Microneedle
patches were shown to swell with water up to 50-fold in volume, depending
on degree of polymer cross-linking, and to collect interstitial fluid
from the skin of rats. To collect analytes from microneedle patches,
the patches were mounted within the cap of microcentrifuge tubes or
formed the top of V-bottom multiwell microplates, and fluid was collected
in the bottom of the tubes under gentle centrifugation. In another
method, microneedle patches were attached to form the bottom of multiwell
microplates, thereby enabling in situ analysis. The simplicity of
biological sample acquisition using microneedle patches coupled with
the simplicity of analyte collection from microneedles patches integrated
into conventional analytical equipment could broaden the reach of
future screening, diagnosis, and monitoring of biomarkers in healthcare
and environmental/workplace settings
Yeast Short-Lived Actin-Associated Protein Forms a Metastable Prion in Response to Thermal Stress
Self-perpetuating ordered protein aggregates (amyloids and prions) are associated with a variety of neurodegenerative disorders. Although environmental agents have been linked to certain amyloid diseases, the molecular basis of their action remains unclear. We have employed endogenous yeast prions as a model system to study environmental control of amyloid formation. A short-lived actin-associated yeast protein Lsb2 can trigger prion formation by other proteins in a mode regulated by the cytoskeleton and ubiquitin-dependent processes. Here, we show that such a heterologous prion induction is due to the ability of Lsb2 to form a transient prion state, generated in response to thermal stress. Evolutionary acquisition of prion-inducing activity by Lsb2 is traced to a single amino acid change, coinciding with the acquisition of thermotolerance in the Saccharomyces yeast lineage. This raises the intriguing possibility that the transient prion formation could aid in functioning of Lsb2 at higher temperatures
Mycorrhiza-Induced Alterations in Metabolome of <i>Medicago lupulina</i> Leaves during Symbiosis Development
The present study is aimed at disclosing metabolic profile alterations in the leaves of the Medicago lupulina MlS-1 line that result from high-efficiency arbuscular mycorrhiza (AM) symbiosis formed with Rhizophagus irregularis under condition of a low phosphorus level in the substrate. A highly effective AM symbiosis was established in the period from the stooling to the shoot branching initiation stage (the efficiency in stem height exceeded 200%). Mycorrhization led to a more intensive accumulation of phosphates (glycerophosphoglycerol and inorganic phosphate) in M. lupulina leaves. Metabolic spectra were detected with GS-MS analysis. The application of complex mathematical analyses made it possible to identify the clustering of various groups of 320 metabolites and thus demonstrate the central importance of the carbohydrate and carboxylate-amino acid clusters. The results obtained indicate a delay in the metabolic development of mycorrhized plants. Thus, AM not only accelerates the transition between plant developmental stages but delays biochemical “maturation” mainly in the form of a lag of sugar accumulation in comparison with non-mycorrhized plants. Several methods of statistical modeling proved that, at least with respect to determining the metabolic status of host-plant leaves, stages of phenological development have priority over calendar age
The Role of <i>Medicago lupulina</i> Interaction with <i>Rhizophagus irregularis</i> in the Determination of Root Metabolome at Early Stages of AM Symbiosis
The nature of plant–fungi interaction at early stages of arbuscular mycorrhiza (AM) development is still a puzzling problem. To investigate the processes behind this interaction, we used the Medicago lupulina MlS-1 line that forms high-efficient AM symbiosis with Rhizophagus irregularis. AM fungus actively colonizes the root system of the host plant and contributes to the formation of effective AM as characterized by a high mycorrhizal growth response (MGR) in the host plant. The present study is aimed at distinguishing the alterations in the M. lupulina root metabolic profile as an indicative marker of effective symbiosis. We examined the root metabolome at the 14th and 24th day after sowing and inoculation (DAS) with low substrate phosphorus levels. A GS-MS analysis detected 316 metabolites. Results indicated that profiles of M. lupulina root metabolites differed from those in leaves previously detected. The roots contained fewer sugars and organic acids. Hence, compounds supporting the growth of mycorrhizal fungus (especially amino acids, specific lipids, and carbohydrates) accumulated, and their presence coincided with intensive development of AM structures. Mycorrhization determined the root metabolite profile to a greater extent than host plant development. The obtained data highlight the importance of active plant–fungi metabolic interaction at early stages of host plant development for the determination of symbiotic efficiency