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101.
Viola G Vedaldi D Dall'Acqua F Lampronti I Bianchi N Zuccato C Borgatti M Gambari R 《Journal of photochemistry and photobiology. B, Biology》2008,92(1):24-28
Psoralens, also known as furocoumarins, are a well-known class of photosensitizers largely used in the therapy of various skin disease. In this study we have evaluated the effects of crude pre-irradiated solutions of furocoumarins derivatives on (a) erythroid differentiation and apoptosis of human leukemic K562 cells and (b) hemoglobin synthesis in cultures of human erythroid progenitors derived from the peripheral blood. To prove the activity of a mixture of photoproducts generated by UVA irradiation of the three psoralen derivatives 5-methoxypsoralen (5-MOP) 8-methoxypsoralen (8-MOP), and angelicin (ANG), we employed the human leukemic K562 cell line and the two-phase liquid culture procedure for growing erythroid progenitors. The results obtained demonstrate that pre-irradiated solutions of psoralen derivatives significantly induce erythroid differentiation of K562 cells irrespective of the type of derivative used, suggesting that the active photoproduct(s) share a common structure. Interestingly, solutions of psoralens irradiated in anaerobic conditions do not exhibits erythroid inducing ability, indicating that the effect is mostly due to photooxidized psoralen products. In erythroid precursor cells, psoralens photolysis products stimulates at low concentrations an increase of hemoglobin A and hemoglobin F. Altogether, these data suggest that photoproducts of psoralen warrant further evaluation as potential therapeutic drugs in beta-thalassaemia and sickle cell anaemia. 相似文献
102.
Summary In this paper we present the experimental results of time-resolved variations of the apparent pitch of a cholesteric mixture
after a steplike shearing deformation is applied to it. We show that the relative variation of the wave-length of the maximum
reflection ΔP/P
o
varies from initial positive values (P>P
0) to negative ones (P<P
0 after a few seconds and finally it tends to a saturation value with ΔP/P
0<0 in a long time. A qualitative explanation based on the mechanism of the unwinding of the twisted helix structure and a
possible tilt of the molecular is also given.
Riassunto In questo lavoro sono presentati i risultati sperimentali della variazione risolta nel tempo del passo apparente di un CLC sottoposto ad una deformazione di taglio a gradino. Si mostra che la variazione relativa della lunghezza d’onda del massimo di riflessione ΔP/P 0 varia da un valore iniziale positivo (P>P 0) ad un valore negativo (P<P 0) dopo pochi secondi, e tende ad un valore di stturazione con ΔP/P 0<0 all’infinito. Noi diamo una spiegazione qualitativa basata sul meccanismo dello srotolamento della struttura elicoidale e sul possibile tilt degli strati molecolari.
Резюме В этой статье приводятся экспериментальные результаты для разрешенных во времени изменений видимого шага холестеричиой смеси после приложения ступенчатой деформации сдвига. Мы показываем, что относительное изменение длины волны максимального отражения ΔP/P 0 изменяется от начальных ппложительных знаьений (P<P 0) до отрицательных значениь (P<P 0 после нескольких секунд и окончательно стремится к величине насьшения с ΔP/P 0<0 в течение длительного времени. Предлагается качественное объяснение, основанное на механизме структуры закрученной спирали и возможного изменния наклона молекул.相似文献
103.
104.
Paola Antoniotti Stefano Borocci Nicoletta Bronzolino Maria Giordani Felice Grandinetti 《ChemInform》2006,37(43):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. 相似文献
105.
106.
Ana Rosa Lazo Fraga Josefina Calvo Quintana Giovanni Li Destri Nicoletta Giamblanco Roberta Grazia Toro Francesco Punzo 《Journal of Solid State Electrochemistry》2012,16(3):901-909
In this work, we studied an ion-exchange membrane based on an inert polymer skeleton in which it is dispersed and anchored
a molecule with charged groups able to discriminate and bind positive or negatively charged ions present in a sample. In order
to be ready to work, electromembranes need a complex procedure called activation or conditioning. Although most of the known
literature looks at the subject from an electrochemical point of view, we put forward a structural approach. Membrane conditioning,
in fact, is considered a required step to improve sensor performances and to allow the collection of reproducible data. Even
if this operation is carefully followed by all the operators working with sensors equipped with a membrane, it looks like
that a thoroughly explanation of the working mechanism and a detailed balance of cost and gains has still not been carried
out. As a consequence, we suggest a bulk or membrane approach, where the landscape is mainly characterized by the long-range
structure of the membrane itself. Our findings suggest that membrane conditioning has to be carried out carefully and the
advantages of this pre-treatment can be appreciated especially for very low concentration measurements. The need for the conditioning
mainly results from the necessity of a complete permeation of all the different tortuous channels constituting the membrane
itself. 相似文献
107.
Romolo M. Dorizzi Anna Ferrari Annalisa Rossini Umberta Mozzo Sandra Meneghelli Nicoletta Melloni Paolo Rizzotti 《Accreditation and quality assurance》2008,13(3):133-137
Tumour markers are traditionally requested in fixed panels more than on the basis of specific conditions or professional guidelines,
wasting a large amount of resources with little or no benefit to the patients. In the summer 2004 the optical-reading requests
form used by our laboratory was redesigned; the section “Apparatus” was added and since then tumour markers have been measured
only if the specifically related organ has been simultaneously and coherently marked (e.g. liver when AFP is requested). The
hospital clinical staff has been involved in the project and has been extensively informed through meetings and paper and
electronic newsletters and messages. Thereafter, when the request form has not been correctly completed, a reminder has been
electronically forwarded to the requesting physician asking for more information. In the first trimester of 2006, 30.9% fewer
tumour markers were measured in inpatients than in the first trimester 2004 (e.g. AFP: −37.6%; CEA: −30.6%; CA 19-9: −43%;
TPA: −36.6%); the decrease of outpatients requests in the same period was about 9.2%. Inpatients workload further decreased
in 2006 versus 2005 while the outpatients workload increased. In conclusion, small administrative changes and an intensive
information effort about appropriate requesting of tumour markers induced a relevant workload reduction in a short time.
Presented at the Conference Quality in the Spotlight, March 2006, Antwerp, Belgium. 相似文献
108.
Giovanni De Filpo Nevio Picci Rita Muzzalupo Francesca Iemma Fiore P. Nicoletta Giuseppe Chidichimo 《Liquid crystals》2013,40(2):295-300
Reverse-mode operation films can be achieved with polymer dispersed liquid crystals by many methods. One method consists in the use of either rough or polyimide treated supports in order to induce homeotropic alignment of the initial mixture that will separate in liquid crystal and polymer rich phases. The major disadvantage is the need for mesogenic monomers to keep a good alignment of the liquid crystal after the polymerization process. In this paper we present results concerning the use of an anisometric, non-mesogenic, tailor-made monomer for the preparation of excellent reverse-mode polymer dispersed liquid crystal shutters cast on rough surfaces. The combined use of rough surfaces and non-mesogenic monomers allows us to exceed earlier limits in physical and chemical properties, cost, and device dimensions by the use of a wider class of monomer molecules. 相似文献
109.
Faure E Halusiak E Farina F Giamblanco N Motte C Poelman M Archambeau C Van de Weerdt C Martial J Jérôme C Duwez AS Detrembleur C 《Langmuir : the ACS journal of surfaces and colloids》2012,28(5):2971-2978
A facile and green approach is developed to impart remarkable protection against corrosion to galvanized steel. A protecting multilayer film is formed by alternating the deposition of a polycation bearing catechol groups, used as corrosion inhibitors, with clay that induces barrier properties. This coating does not affect the esthetical aspect of the surface and does not release any toxic molecules in the environment. 相似文献
110.
N'dri D Calani L Mazzeo T Scazzina F Rinaldi M Rio DD Pellegrini N Brighenti F 《Molecules (Basel, Switzerland)》2010,15(10):7125-7138
Gnagnan (Solanum indicum L.) is a spontaneous plant widely distributed in Ivory Coast. During ripening stages, Solanum indicum L. presents different colours (green, yellow and red) and is reported to contain several albeit poorly characterized antioxidant compounds. This paper describes in detail the antioxidant profile (ascorbic acid, carotenoids and polyphenols), antioxidant capacity (FRAP test and Folin-Ciocalteau assay) and the colour changes of Gnagnan berries at different ripening levels. Ascorbic acid content was similar in green and yellow berries, but significantly lower in red ones. Red berries showed a higher content of carotenoids compared to green and yellow ones. Regarding polyphenols, several phenolic acids and flavonoids were found in all berries. The content of caffeoylquinic acids, caffeic acid, flavonol glycosides and naringenin was higher in red berries, while the content of p-coumaric acid and feruloylquinic acids was similar among the three colours. The FRAP assay increased with the ripening process, whereas total polyphenols were similar among berries. Significant differences were found for the colorimetric indexes among products of different degrees of ripening. The present results show the important role of the ripening stage in increasing the antioxidant content of Gnagnan berries. 相似文献