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Sobottka SB Geiger KD Salzer R Schackert G Krafft C 《Analytical and bioanalytical chemistry》2009,393(1):187-195
Infrared spectroscopic imaging is a promising intraoperative tool which enables rapid, on-site diagnosis of brain tumors during
neurosurgery. A classification model was recently developed using infrared spectroscopic images from thin tissue sections
to grade malignant gliomas, the most frequent class of primary brain tumor. In this study the model was applied to 54 specimens
from six patients with inhomogeneous gliomas composed of regions with different tumor density and morphology. The resection
was controlled using neuronavigation which transfers the findings obtained by preoperative magnetic resonance imaging (MRI)
into the operating field. For comparison, all specimens were independently evaluated by histopathology after hematoxylin and
eosin staining. The infrared-derived grading agreed with histopathology and MRI findings for almost all specimens. With regard
to histopathological assessment, sensitivities of 100% (22/22) and 93.1% (27/29) and specificities of 96.9% (31/32) and 88.0%
(22/25) were achieved, depending on whether the classification was based on the predominant or maximal tumor grade, respectively,
in the specimen. Altogether, in 98% (53/54) of all specimens the decision to continue or not continue tumor resection could
have been made according to the infrared spectroscopic classification. This retrospective study clearly demonstrates that
infrared spectroscopic imaging may help to define tumor margins intraoperatively and to detect high-grade tumor residues for
achieving more radical tumor resection.
MRT-guided tumor resection (left) is combined with infrared spectroscopy-based tissue classification (middle, right). With regard to histopathological assessment, sensitivities of 100% and 93.1% and specificities of 96.9% and 88.0% were
achieved for 54 specimens. (TIF 47.1 KB) 相似文献
146.
We study two types of crank moments and two types of rank moments for overpartitions. We show that the crank moments and their derivatives, along with certain linear combinations of the rank moments and their derivatives, can be written in terms of quasimodular forms. We then use this fact to prove exact relations involving the moments as well as congruence properties modulo 3, 5, and 7 for some combinatorial functions which may be expressed in terms of the second moments. Finally, we establish a congruence modulo 3 involving one such combinatorial function and the Hurwitz class number H(n). 相似文献
147.
Stephan Pannier Kathrin Grossenbacher Martin Liebscher Wolfgang Graf Michael Kaliske 《PAMM》2011,11(1):731-732
In many engineering applications, a structural design is determined by way of a multi-stage design process. Thereby, the information of previous simulations, e.g. sensitivity analysis, should be used for further investigations. In special, the aim is to improve the reliability as early as possible. Therefore, an approach is presented to determine alternative permissible design spaces on the basis of arbitrary point sets. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
148.
The effect of freezing on a variety of acidified and neutral, nitrite ion and halide-containing mixtures has been investigated using UV/vis spectroscopy. Several trihalide ions were formed and monitored, including I(2)Cl(-), I(2)Br(-), ICl(2)(-) and IBr(2)(-). A mechanism to explain the observations is given in terms of steps involving INO and the nitroacidium ion, [H(2)ONO](+). The transformation of sea salt components to specific trihalide ions by freezing represents a potentially important process in a polar atmospheric context. This is because the dichloro- and dibromo-trihalide ions can release chlorine- and bromine-containing gases, which are key intermediates in ozone destruction. 相似文献
149.
Ishida K Maksimenka K Fritzsche K Scherlach K Bringmann G Hertweck C 《Journal of the American Chemical Society》2006,128(45):14619-14624
Resistoflavin (1) is a rare boat-shaped pentacyclic polyketide metabolite of Streptomyces resistomycificus with marked antibacterial activity. By a series of experiments we have disclosed that the optically active molecule is derived from the discoid polyketide resistomycin (2) by an unusual, enantioface-differentiating hydroxylation, which leads to the capped pentacyclic ring system. In vivo and in vitro experiments unequivocally demonstrate that this reaction is catalyzed by RemO, an FAD-dependent monooxygenase. In addition, we were able to establish the absolute configuration of 1 and thus the stereochemical course of this rare enzymatic reaction by extensive computational methods. Comparison of the experimental CD spectrum with those quantum chemically calculated for (R)-1 and (S)-1 revealed the R-configuration of 1. Consequently, the enzyme-catalyzed hydroxylation takes place from the Re-face of 2 with loss of aromaticity in favor of a chiral carbinol center. While other oxygenases involved in polyketide tailoring functionalize the periphery of polyphenols, RemO is unique in its ability to catalyze a central, nonperipheral hydroxylation of a fused ring system. 相似文献
150.
Daniele Addis Nadim Shaikh Shaolin Zhou Shoubhik Das Kathrin Junge Dr. Matthius Beller Prof. Dr. 《化学:亚洲杂志》2010,5(7):1687-1691
The reduction of ketones with polymethylhydrosiloxane (PMHS) gives the corresponding alcohols in good to excellent yield applying iron‐based catalyst systems. In the case of prochiral ketones, the use of Fe(OAc)2/(S,S)‐Me‐DuPhos leads to high enantioselectivity up to 99 % ee. The reaction proceeds in the presence of several functional groups such as esters, halides as well as conjugated double bonds, with high chemoselectivity. The advantage of this protocol is that the reaction requires no activating agents or additives. 相似文献