Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
J Relig Health ; 58(1): 246-258, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30306388

RESUMO

Most patients want to discuss their religious and spiritual concerns, yet few physicians discuss it. First-year medical students (n = 92) interviewed a standardized patient experiencing spiritual distress. There was a significant difference among the students' reasoning for their (dis)comfort and (mis)matching religion with their patient (X2 = 21.0831, p < .05). Most students whose religion matched their patient felt comfortable because of having this in common with their patient. Most students whose religion did not match that of their patient ascribed their comfort to their religious belief to be open and accepting. Discomfort may stem from more individual factors than a (mis)match in religion, as most of the students reported feeling comfortable.


Assuntos
Relações Médico-Paciente , Médicos , Religião , Estudantes de Medicina , Emoções , Humanos , Espiritualidade
2.
Ecol Lett ; 20(1): 78-86, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28000432

RESUMO

Rising temperatures are amplifying drought-induced stress and mortality in forests globally. It remains uncertain, however, whether tree mortality across drought-stricken landscapes will be concentrated in particular climatic and competitive environments. We investigated the effects of long-term average climate [i.e. 35-year mean annual climatic water deficit (CWD)] and competition (i.e. tree basal area) on tree mortality patterns, using extensive aerial mortality surveys conducted throughout the forests of California during a 4-year statewide extreme drought lasting from 2012 to 2015. During this period, tree mortality increased by an order of magnitude, typically from tens to hundreds of dead trees per km2 , rising dramatically during the fourth year of drought. Mortality rates increased independently with average CWD and with basal area, and they increased disproportionately in areas that were both dry and dense. These results can assist forest managers and policy-makers in identifying the most drought-vulnerable forests across broad geographic areas.


Assuntos
Secas , Florestas , Longevidade , Árvores/fisiologia , California , Clima , Mudança Climática , Estações do Ano
3.
J Org Chem ; 78(11): 5364-71, 2013 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-23663054

RESUMO

The synthesis of a globular macromolecule and its application as a bimolecular catalyst are reported. The macromolecular structure supports (at least) two zinc-metalated porphyrin units, each capable of binding a single reactant. The proximity of the two bound reactants results in an increased local concentration, leading to a maximum 300-fold increase in the reaction rate. In contrast to other synthetic catalysts, where bidentate products inhibit further reactions, this macromolecular system allows the product to be displaced by the reactants leading to turnover and catalysis. We believe that this is due to the dynamics of the macromolecular host system, which maintains enough flexibility to adopt a favorable/reactive geometry, which allows the reactants to get close and react while possessing sufficient rigidity/poor geometry to reduce and disrupt any cooperative/inhibitive bidentate binding.


Assuntos
Substâncias Macromoleculares/química , Metaloporfirinas/química , Zinco/química , Catálise , Substâncias Macromoleculares/síntese química , Metaloporfirinas/síntese química , Estrutura Molecular
4.
Chem Soc Rev ; 41(18): 6138-59, 2012 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-22850803

RESUMO

Nature uses the principles of encapsulation and supramolecular chemistry to bind and orientate substrates within active catalytic sites. Over the years, synthetic chemistry has generated a number of small molecule active site mimics capable of catalysing reactions involving bound substrates. Another approach uses larger molecules that better represent an enzymes globular structure. These molecules mimic an enzymes structure by incorporating binding/catalytic sites within the globular structure of the polymer. As such, the electronic and steric properties around the binding/catalytic site(s) can be controlled and fine-tuned. One class of polymer that is particularly adept at mimicking the globular structure of enzymes are dendritic polymers. This review will concentrate on the use of hyperbranched polymers as synthetic enzyme mimics.


Assuntos
Materiais Biomiméticos/química , Dendrímeros/química , Polímeros/química , Biocatálise , Catálise , Domínio Catalítico
5.
New Phytol ; 129(1): 155-163, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33874419

RESUMO

The reproductive behaviour of Gentiana pneumonanthe L., a rare plant species in The Netherlands, was studied in a relatively large wet heathland population during summer 1989. The species co-occurred with the grass Molinia caerulea and co-flowered with Erica tetralix and Calluna vulgaris. The flowering period lasted from July to October, peaking in late August to late September. Flowers are protandrous. The species appeared to be self-compatible, but spontaneous self-pollination was strongly limited. Hand-crossing and hand-selfing resulted in the same amount of seed set as in natural pollination. Reproductive success was dramatically reduced late in the season. Pollination was achieved sternotribically by the species Bombus pascuorum, which visited the flowers for nectar. In the study area, three patch types were distinguished: co-dominated by Erica, by Calluna and Erica, and by Molinia, respectively. Frequency of visits to Gentiana was highest in the Erica-patch. However, this did not result in a higher seed set. In the Molinia-patch seed set was reduced. However, in the Molinia-patch the mean number of ovules was greater than in the others (as high as in plants raised indoors and in cross-pollinated plants). Fruits from the Calluna-patch had less ovules than those from the Erica-patch. We conclude that, in this remnant population, Gentiana is not pollination-limited. However, it is likely that in the Molinia-patch geitonogamy is frequent, which may lead to inbreeding depression. The greater number of ovules observed in Molinia-patches may reflect an excess of nutrients available there, relative to the Calluna-patch where there may be reduced water availability.

6.
Chem Commun (Camb) ; 49(73): 8063-5, 2013 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-23903030

RESUMO

As dendrimers approach their dense shell or dense packed limit, a certain amount of conformational organization exists. Any substrate binding within the dendrimer's external layer will experience the same organizational effects. This paper describes how these effects can be exploited towards stereocontrol with respect to binding and reactivity.


Assuntos
Dendrímeros/química , Aminas/química , Conformação Molecular , Estereoisomerismo
7.
Ecol Evol ; 3(16): 5237-53, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24455152

RESUMO

In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum-Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum-Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This approach can also be implemented in other systems where the target species is closely interacting with other taxa.

8.
Chem Commun (Camb) ; 48(1): 154-6, 2012 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-22039580

RESUMO

This communication describes the use of non-covalent chemistry to construct recyclable porphyrin cored HBPs. The non-covalent design allows the polymeric backbone to be rescued and reused after porphyrin degradation. The steric environment within the polymeric encapsulated ligand notably affected the porphyrin coordination geometry.


Assuntos
Materiais Biomiméticos/química , Hemeproteínas/química , Polímeros/química , Porfirinas/química , Piridinas/química , Ligantes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA