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951.
[Structure: see text] Homoallylic amines and alpha-amino esters were prepared via a Pd(II)-catalyzed coupling of boronic acids and 1,2-nonadiene with ethyl iminoacetate or aliphatic, aromatic, and heteroaromatic imines. The allylpalladium umpolung was induced by a Pd(OAc)2 catalyst with commercial phosphine ligands. 相似文献
952.
953.
Isabel Marques Rodrigues Amaral Jo?o Felipe Moreira Neto Gustavo Borges Pereira Mariani Borges Franco Marcelo Emílio Beletti Warwick Estevam Kerr Ana Maria Bonetti Carlos Ueira-Vieira 《Micron (Oxford, England : 1993)》2010,41(2):123-129
Infection in insects stimulates a complex defensive response. Recognition of pathogens may be accomplished by plasma or hemocyte proteins that bind specifically to bacterial or fungal polysaccharides. Several morphologically distinct hemocyte cell types cooperate in the immune response. Hemocytes attach to invading organisms and then isolate them by phagocytosis, by trapping them in hemocyte aggregates called nodules, or by forming an organized multicellular capsule around large parasites. In the current investigation the cellular in the hemolymph third instar larvae of M. scutellaris has been characterized by means of light microscopy analysis and phagocytosis assays were performed in vivo by injection of 0.5 μm fluorescence beads in order to identify the hemocyte types involved in phagocytosis. Four morphotypes of circulating hemocytes were found in 3rd instar larvae: prohemocytes, plasmatocytes, granulocytes and oenocytoids. The results presented plasmatocytes and granulocytes involved in phagocytic response of foreign particles in 3rd instar larvae of M. scutellaris. 相似文献
954.
Flávia?Rodrigues?de Oliveira Silva Maria?Helena?Bellini Vivian?Regina?Trist?o Nestor?Schor Nilson?Dias?VieiraJr. Lilia?Coronato?Courrol 《Journal of fluorescence》2010,20(6):1159-1165
Prostate cancer is one of the most common types of cancer in men, and unfortunately many prostate tumours remain asymptomatic
until they reach advanced stages. Diagnosis is typically performed through Prostate-Specific Antigen (PSA) quantification,
Digital Rectal Examination (DRE) and Transrectal Ultrasonography (TU). The antigen (PSA) is secreted by all prostatic epithelial
cells and not exclusively by cancerous ones, so its concentration also increases in the presence of other prostatic diseases.
DRE and TU are not reliable for early detection, when histological analysis of prostate tissue obtained from a biopsy is necessary.
In this context, fluorescence techniques are very important for the diagnosis of cancer. In this paper we explore the potential
of using endogenous phorphyrin blood fluorescence as tumour marker for prostate cancer. Substances such as porphyrin derivatives
accumulate substantially more in tumours than in normal tissues; thus, measuring blood porphyrin concentration by autofluorescence
intensity may provide a good parameter for determining tumour stage. In this study, the autofluorescence of blood porphyrin
was analyzed using fluorescence and excitation spectroscopy on healthy male NUDE mice and in those with prostate cancer induced
by inoculation of DU145 cells. A significant contrast between the blood of normal and cancer subjects could be established.
Blood porphyrin fluorophore showed an enhancement on the fluorescence band around 632 nm following tumour growth. Fluorescence
detection has advantages over other light-based investigation methods: high sensitivity, high speed and safety. However it
does carry the drawback of low specificity of detection. The extraction of blood porphyrin using acetone can solve this problem,
since optical excitation of further molecular species can be excluded, and light scattering from blood samples is negligible. 相似文献
955.
Felizardo M Morlat T Fernandes AC Girard TA Marques JG Ramos AR Auguste M Boyer D Cavaillou A Sudre C Poupeney J Payne RF Miley HS Puibasset J;SIMPLE Collaboration 《Physical review letters》2010,105(21):211301
We report results of a 14.1 kg d measurement with 15 superheated droplet detectors of total active mass 0.208 kg, comprising the first stage of a 30 kg d Phase II experiment. In combination with the results of the neutron-spin sensitive XENON10 experiment, these results yield a limit of |a(p)|<0.32 for M(W)=50 GeV/c2 on the spin-dependent sector of weakly interacting massive particle-nucleus interactions with a 50% reduction in the previously allowed region of the phase space, formerly defined by XENON, KIMS, and PICASSO. In the spin-independent sector, a limit of 2.3×10?? pb at M(W)=45 GeV/c2 is obtained. 相似文献
956.
Josef Rudinger Helena Maassen Van Den Brink-Zimmermannov 《Helvetica chimica acta》1973,56(7):2216-2226
Using an extraction procedure which permits determination of end-points, the reduction of a number of tosylamino acids, their derivatives, and model compounds with sodium in liquid ammonia has been investigated. When the molecule contains a single acidic group in addition to the tosylamino group (as in the case of the simple mono-tosylamino monocarboxylic acids) reduction proceeds with the consumption of 2 g-at. Na per tosyl group and the formation of toluene-4-sulphinic acid. If the number of acidic groups in the products is insufficient to accommodate the number of electrons consumed in the reduction, the reduction of ionisable tosylamino groups is incomplete unless an acid is added. If the number of acidic groups is higher, or excess acid is added, the sulphur-containing products include thiocresol and sulphite. This last reaction course is also observed whenever calcium is used in place of sodium. A partial interpretation of the results is offered. 相似文献
957.
Steven Van Petegem Danny Segers Charles Dauwe Florian dalla Torre Helena Van Swygenhoven 《Monatshefte für Chemie / Chemical Monthly》2002,133(6):829-836
Summary. Nanostructured Ni3Al was produced by the inert gas condensation and in situ compaction technique and characterized by means of high-resolution transmission electron microscopy (HRTEM), X-ray diffraction,
and density measurements. The defect structure was investigated using positron annihilation lifetime spectroscopy (PALS).
It is shown that in some samples besides the cubic also the martensitic phase can be present. The defect structure can be
divided into three major components: vacancy-like defects in the grain boundaries and nano-voids with a size of 1 nm as seen
with PALS, and large pores with sizes up to 8 nm as seen with HRTEM. Furthermore, it is shown that an increasing compaction
temperature leads to significantly smaller nano-voids.
Received October 5, 2001. Accepted (revised) November 12, 2001 相似文献
958.
959.
Maria Helena Noronha 《Geometriae Dedicata》1993,47(3):255-268
In this paper we study some compact locally conformally flat manifolds with a compatible metric whose scalar curvature is nonnegative, and in particular with nonnegative Ricci curvature. In the last section we study such manifolds of dimension 4 and scalar curvature identically zero. 相似文献
960.
Maria Helena W. Morelli-Cardoso Regina T. M. Cardozo Jaíza L. Mello Shirley Abrantes Ktia M. P. Menezes 《Journal of separation science》1999,22(11):619-622
A method is described for the simultaneous extraction and determination of twenty organochlorine pesticides residues [hexachlorocyclohexane (HCH) isomers (α, β, γ, δ), aldrin, dieldrin, endrin, heptachlor and its epoxide (HE), hexachlorobenzene (HCB), α-endosulfan, o,p′-DDD, p,p′-DDD, o,p′-DDE, p,p′-DDE, o,p′-DDT, p,p′-DDT, dicofol, methoxychlor, and mirex] that were spiked in tomatoes. Samples were extracted with ethyl acetate, and the extract was subjected to a rapid clean-up using a Florisil column. The residues were determined by GLC-ECD using two columns of different polarity. The calibration graph correlation coefficient ranged from 0.9903 to 0.9990. The recoveries ranged from 95 to 99% with relative standard deviation ranging from 0.5 to 14.7% in the concentration range 0.005 to 0.2 μg/g. The limits of detection ranged from 0.004 to 0.05 μg/g and the limits of quantification ranged from 0.005 to 0.174 μg/g. 相似文献