Search results for "ACID"
showing 10 items of 13107 documents
Synthesis of Polycyclic Indolines utilizing a reduction/cyclization cascade reaction
2021
Subsequent reduction and dearomatizing cyclization reactions open up an entry into the synthesis of novel N-fused polycyclic indolines. The dearomatizing cyclization as key step of the sequence proceeds well with Cu(OTf)2 or TfOH as catalyst. At elevated temperature reduction of nitro-substituted precursors with iron under acidic conditions affords a broad variety of polycyclic indolines directly in a two-step cascade reaction in good to excellent yields. Using the developed protocol, the alkaloids Tryptanthrin and Phaitanthrin C have been prepared. peerReviewed
Optimizing the SYBR green related cyanine dye structure to aim for brighter nucleic acid visualization
2022
In recent years, the studies of RNA and its use for the development of RNA based vaccines have increased drastically. Although cyanine dyes are commonly used probes for studying nucleic acids, in a wide range of applications, there is still a growing need for better and brighter dyes. To meet this demand, we have systematically studied the structure of SYBR green-related cyanine dyes to gain a deeper understanding of their interactions with biomolecules especially how they interact with nucleic acids and the structural components which makes them strongly fluorescent. Herein, five new dyes were synthesized, and their photophysical properties were evaluated. Observations of photophysical cha…
Phytoplankton group identification with chemotaxonomic biomarkers: In combination they do better
2023
Chemotaxonomic biomarkers are needed to monitor and evaluate the nutritional quality of phytoplankton communities. The biomolecules produced by different phytoplankton species do not always follow genetic phylogeny. Therefore, we analyzed fatty acids, sterols, and carotenoids from 57 freshwater phytoplankton strains to evaluate the usability of these biomolecules as chemotaxonomic biomarkers. We found 29 fatty acids, 34 sterols, and 26 carotenoids in our samples. The strains were grouped into cryptomonads, cyanobacteria, diatoms, dinoflagellates, golden algae, green algae, and raphidophytes, and the phytoplankton group explained 61%, 54%, and 89% of the variability of fatty acids, sterols, …
Plasma polyunsaturated fatty acids are directly associated with cognition in overweight children but not in normal weight children
2016
Aim Polyunsaturated fatty acids are essential nutrients for the normal development of the brain. We investigated the associations between plasma polyunsaturated fatty acids and cognition in normal weight and overweight children. Methods The study recruited 386 normal weight children and 58 overweight children aged six to eight years and blood samples were drawn after a 12-hour fast. We assessed plasma polyunsaturated fatty acids using gas chromatography, cognition using Raven's Coloured Progressive Matrices, and overweight and obesity using the age-specific and sex-specific cut-offs from the International Obesity Task Force. The data were analysed by linear regression analyses adjusted for …
Sphingomyelin induces structural alteration in canine parvovirus capsid
2008
One of the essential steps in canine parvovirus (CPV) infection, the release from endosomal vesicles, is dominated by interactions between the virus capsid and the endosomal membranes. In this study, the effect of sphingomyelin and phosphatidyl serine on canine parvovirus capsid and on the phospholipase A2 (PLA2) activity of CPV VP1 unique N-terminus was analyzed. Accordingly, a significant (P ≤ 0.05) shift of tryptophan fluorescence emission peak was detected at pH 5.5 in the presence of sphingomyelin, whereas at pH 7.4 a similar but minor shift was observed. This effect may relate to the exposure of VP1 N-terminus in acidic pH as well as to interactions between sphingomyelin and CPV. When…
Acid-catalyzed mechanocatalytic pretreatment to improve sugar release from birch sawdust : Structural and chemical aspects
2022
This study examined acid-catalyzed mechanocatalytic pretreatment of birch sawdust without a separate impregnation step. Catalyst amount and pretreatment time were the key variables. Pretreated material was mixed with water for hydrolysis (100 °C, 60 min). The efficient release of total reducing sugars from birch sawdust is significant to the path towards biofuels and biochemicals. Based on the results, the structure and surface of birch sawdust changed as a function of mechanocatalytic pretreatment. Milling time caused significant transformations in birch structure and also increased the yields of reducing sugars. The highest yield of total reducing sugar from pretreated sawdust was 23.0% a…
Modyfikacja polietylenu kwasem itakonowym
2003
W celu nadania właściwości hydrofilowych, które powinny ułatwić rozkład odpadów w środowisku naturalnym, przeprowadzono szczepienie PE-LD kwasem itakonowym (KI) wobec nadtlenku dikumylu (DCP). Proces realizowano dwuetapowo w wytłaczarce jednoślimakowej, stosując różne stężenia KI (3—10% mas.) i DCP (do 1,1% mas.). Metodą pirolitycznej chromatografiigazowej (Py/GC/MS) zidentyfikowano produkty termicznego rozkładu KI. Analiza FT-IR wykluczyła ich obecność w kompozycjach po szczepieniu, natomiast sugerowała szczepienie KI. Metodą ekstrakcji wodnej ustalono, że wraz ze wzrostem stężenia KI i DCP wzrasta stopień szczepienia, natomiast w całym badanym zakresie stężeń DCP w kompozycjach zawierając…
Oddziaływanie kadmu i kwasu salicylowego na aktywność metaboliczną Lepidium sativum L.
2016
Kadm (Cd) jest metalem ciężkim, który w wyniku działań człowieka stał się głównym zanieczyszczeniem środowiska. Charakteryzuje się wysoką toksycznością dla wszystkich organizmów żywych. Symptomem toksyczności kadmu dla roślin są przede wszystkim zmiany morfologiczne, ograniczenie procesów fotosyntezy oraz stres oksydacyjny. Efekt zwiększenia odporności na stres można uzyskać, stosując różne związki egzogenne. Do takich związków należy między innymi kwas salicylowy (SA). Celem niniejszej pracy jest ocena wpływu kwasu salicylowego na stres metaboliczny u pieprzycy siewnej Lepidium sativum wywołany wzrastającymi stężeniami kadmu. W liściach pieprzycy siewnej oznaczano ilości białka, chlorofilu…
Monovalent cation conductance in Xenopus laevis oocytes expressing hCAT-3
2005
hCAT-3 (human cationic amino acid transporter type three) was investigated with both the two-electrode voltage clamp method and tracer experiments. Oocytes expressing hCAT-3 displayed less negative membrane potentials and larger voltage-dependent currents than native or water-injected oocytes did. Ion substitution experiments in hCAT-3-expressing oocytes revealed a large conductance for Na + and K + . In the presence of l-Arg, voltage-dependent inward and outward currents were observed. At symmetrical (inside/outside) concentrations of l-Arg, the conductance of the transporter increased monoexponentially with the l-Arg concentrations; the calculated Vmax and KM values amounted to 8.3 AS and…
Explorando las desigualdades sociales y formas de contrarrestarlas
2019
Production of INCASI Project H2020-MSCA-RISE-2015 GA 691004 La propuesta de este artículo es presentar una experiencia actual de innovación docente en la que se vincula la enseñanza de la Sociología con la investigación desarrollada en el proyecto europeo INCASI: International Network for Comparative Analysis of Social Inequalities. La experiencia docente se aplica en la asignatura de Sociología, con alumnado de primer curso, del grado de Gestión y Administración Pública, de la Facultad de Derecho, de la Universidad de Barcelona. El eje central del trabajo desarrollado por el alumnado es realizar una investigación sociológica exploratoria sobre una desigualdad social y observar e idear polí…