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1.
ChemSusChem ; 17(13): e202400036, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38376952

RESUMO

The hydrogenation of polyunsaturated fatty acids (PUFAs) in vegetable oils and their derivatives is essential for their use in many areas, such as biofuels and food chemistry. However, no attempts have been made to adapt this technology to the requirements of further chemical utilization of fatty acid methyl esters as molecular building blocks, especially for particularly promising double-bond reactions. In this work, we, therefore, use three homogeneous catalytic model reactions (hydroformylation, isomerizing methoxycarbonylation, and ethenolysis) to show, firstly, that it is already known from the literature that high PUFA contents have a negative impact on activity and selectivity. Subsequently, using the example of soybean and canola biodiesel, we demonstrate that these key figures can be drastically improved by a preceding selective partial hydrogenation. This makes it possible to first reduce the share of PUFAs to <1 w % without causing significant overhydrogenation and then to carry out hydroformylation, methoxycarbonylation, and ethenolysis with significantly increased activity (up to twentyfold) and selectivity (up to 80 % increase). With these findings, we hope to convince the scientific and industrial world of the potential of selective partial hydrogenation as a key technology for utilizing renewable raw materials and to encourage its effective use in future work.

2.
Viruses ; 15(3)2023 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-36992499

RESUMO

Tick-borne encephalitis (TBE) is a viral disease endemic in Eurasia. The virus is mainly transmitted to humans via ticks and occasionally via the consumption of unpasteurized milk products. The European Centre for Disease Prevention and Control reported an increase in TBE incidence over the past years in Europe as well as the emergence of the disease in new areas. To better understand this phenomenon, we investigated the drivers of TBE emergence and increase in incidence in humans through an expert knowledge elicitation. We listed 59 possible drivers grouped in eight domains and elicited forty European experts to: (i) allocate a score per driver, (ii) weight this score within each domain, and (iii) weight the different domains and attribute an uncertainty level per domain. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped into three terminal nodes using a regression tree analysis. The drivers with the highest scores were: (i) changes in human behavior/activities; (ii) changes in eating habits or consumer demand; (iii) changes in the landscape; (iv) influence of humidity on the survival and transmission of the pathogen; (v) difficulty to control reservoir(s) and/or vector(s); (vi) influence of temperature on virus survival and transmission; (vii) number of wildlife compartments/groups acting as reservoirs or amplifying hosts; (viii) increase of autochthonous wild mammals; and (ix) number of tick species vectors and their distribution. Our results support researchers in prioritizing studies targeting the most relevant drivers of emergence and increasing TBE incidence.


Assuntos
Dermacentor , Encefalite Transmitida por Carrapatos , Ixodes , Animais , Humanos , Europa (Continente)/epidemiologia , Animais Selvagens , Mamíferos
3.
Appl Environ Microbiol ; 76(10): 3293-300, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20363798

RESUMO

Botulinum neurotoxin (BoNT) is the most toxic substance known to man and the causative agent of botulism. Due to its high toxicity and the availability of the producing organism Clostridium botulinum, BoNT is regarded as a potential biological warfare agent. Because of the mild pasteurization process, as well as rapid product distribution and consumption, the milk supply chain has long been considered a potential target of a bioterrorist attack. Since, to our knowledge, no empirical data on the inactivation of BoNT in milk during pasteurization are available at this time, we investigated the activities of BoNT type A (BoNT/A) and BoNT/B, as well as their respective complexes, during a laboratory-scale pasteurization process. When we monitored milk alkaline phosphatase activity, which is an industry-accepted parameter of successfully completed pasteurization, our method proved comparable to the industrial process. After heating raw milk spiked with a set amount of BoNT/A or BoNT/B or one of their respective complexes, the structural integrity of the toxin was determined by enzyme-linked immunosorbent assay (ELISA) and its functional activity by mouse bioassay. We demonstrated that standard pasteurization at 72 degrees C for 15 s inactivates at least 99.99% of BoNT/A and BoNT/B and at least 99.5% of their respective complexes. Our results suggest that if BoNTs or their complexes were deliberately released into the milk supply chain, standard pasteurization conditions would reduce their activity much more dramatically than originally anticipated and thus lower the threat level of the widely discussed "BoNT in milk" scenario.


Assuntos
Toxinas Botulínicas/química , Clostridium botulinum/fisiologia , Contaminação de Alimentos/prevenção & controle , Temperatura Alta , Leite/química , Fosfatase Alcalina/metabolismo , Animais , Toxinas Botulínicas/análise , Toxinas Botulínicas/toxicidade , Ensaio de Imunoadsorção Enzimática , Contaminação de Alimentos/análise , Masculino , Camundongos , Sensibilidade e Especificidade , Testes de Toxicidade Aguda
4.
Reproduction ; 122(3): 487-95, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11597314

RESUMO

During ovarian folliculogenesis, ascorbic acid may be involved in collagen biosynthesis, steroidogenesis and apoptosis. The aims of this study were to determine the effects of ascorbic acid on bovine follicle development in vitro. Preantral follicles were cultured for 12 days in serum-free medium containing ascorbic acid (50 microg ml(-1)). Half of the medium was replaced every 2 days, and conditioned medium was analysed for oestradiol and matrix metalloproteinase 2 (MMP-2) and MMP-9 secretion. On day 12, cell death was assessed by TdT-mediated dUTP-biotin nick end labelling (TUNEL). In the absence of serum, there was significant (P < 0.05) follicle growth and oestradiol secretion over the 12 day culture period. Ascorbic acid had no effect on these parameters. The addition of serum from day 0 stimulated follicle growth (P < 0.05), but compromised follicle integrity. By day 12 of culture, a higher proportion of follicles remained intact in the presence of ascorbic acid in serum-free conditions (P < 0.05), and significantly (P < 0.01) less granulosa and theca cell death was observed in these follicles than in control follicles. Moreover, ascorbic acid significantly (P < 0.05) increased production of MMP-9, an enzyme involved in basement membrane remodelling. In conclusion, this culture system was capable of supporting follicle differentiation over the 12 day culture period. Furthermore, ascorbic acid maintains bovine follicle health and basement membrane remodelling in vitro.


Assuntos
Ácido Ascórbico/farmacologia , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/fisiologia , Animais , Membrana Basal/fisiologia , Bovinos , Morte Celular , Meios de Cultivo Condicionados , Meios de Cultura Livres de Soro , Técnicas de Cultura , Estradiol/metabolismo , Feminino , Células da Granulosa/citologia , Marcação In Situ das Extremidades Cortadas , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Folículo Ovariano/anatomia & histologia , Células Tecais/citologia , Fatores de Tempo
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