다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Achieving a spatial resolution that is not limited by the diffraction of light, recent developments of super-resolution fluorescence microscopy techniques allow the observation of many biological structures not resolvable in conventional fluorescence microscopy. New advances in these techniques now give them the ability to image three-dimensional (3D) structures, measure interactions by multicolor colocalization, and record dynamic processes in living cells at the nanometer scale. It is anticipated that super-resolution fluorescence microscopy will become a widely used tool for cell and tissue imaging to provide previously unobserved details of biological structures and processes.

/pdf/super-resolution-fluorescence-microscopy-v84c1ojckz.pdf

Super-Resolution Fluorescence Microscopy

Recent advances in fluorescent probe technology have improved spatial and temporal resolution, bringing us closer to the ideal of imaging individual cellular features in real time with molecular (1–5 nm) resolution. In parallel, the development of super-resolution imaging techniques has revolutionized fluorescence microscopy. In 1873, Ernst Abbe discovered that features closer than ∼200 nm cannot be resolved by lens-based light microscopy. In recent years, however, several new far-field super-resolution imaging techniques have broken this diffraction limit, producing, for example, video-rate movies of synaptic vesicles in living neurons with 62 nm spatial resolution. Current research is focused on further improving spatial resolution in an effort to reach the goal of video-rate imaging of live cells with molecular (1–5 nm) resolution. Here, we describe the contributions of fluorescent probes to far-field super-resolution imaging, focusing on fluorescent proteins and organic small-molecule fluorophores. We describe the features of existing super-resolution fluorophores and highlight areas of importance for future research and development.

/pdf/fluorescent-probes-for-super-resolution-imaging-in-living-344ty555xt.pdf

Fluorescent probes for super-resolution imaging in living cells

Metal-mediated and metal-catalyzed reactions of isocyanides.

This review is focused on the analysis of current data on new methods of alkenylation of arenes and heteroarenes with alkynes by transition metal catalyzed reactions, Bronsted/Lewis acid promoted transformations, and others. The synthetic potential, scope, limitations, and mechanistic problems of the alkenylation reactions are discussed. The insertion of an alkenyl group into aromatic and heteroaromatic rings by inter- or intramolecular ways provides a synthetic route to derivatives of styrene, stilbene, chalcone, cinnamic acid, various fused carbo- and heterocycles, etc.

Alkenylation of Arenes and Heteroarenes with Alkynes.

By combining the photoswitching and localization of individual fluorophores with spectroscopy on the single molecule level, we demonstrate simultaneous multicolor imaging with low crosstalk and down to 15 nm spatial resolution using only two detection color channels. The applicability of the method to biological specimens is demonstrated on mammalian cells. The combination of far-field fluorescence nanoscopy with the recording of a single switchable molecular species at a time opens up a new class of functional imaging techniques.

Multicolor Far-Field Fluorescence Nanoscopy through Isolated Detection of Distinct Molecular Species

Acyclic diaminocarbenes (ADCs) as a promising alternative to N-heterocyclic carbenes (NHCs) in transition metal catalyzed organic transformations

Caged (that is, masked) fluorescent dyes are maintained in their nonfluorescent state by the incorporation of a photochemical labile group. The photosensitive masking group or “molecular cage” can be cleaved-off by irradiation with nearUV light, thereby rendering the dye fluorescent. Caged fluorescent dyes are of enormous interest for biological imaging because they may be used, for example, for the analysis of protein dynamics, multicolor fluorescence microscopy, and far-field optical nanoscopy. o-Nitrobenzyl groups are often used as masking groups; however, the use of these dyes is limited because of their rather complex synthesis and the unwanted by-products liberated by photolysis. Herein we report on the synthesis and characterization of a novel class of caged compounds—rhodamine NN dyes, which have a 2-diazoketone (COCNN) caging group incorporated into a spiro-9H-xanthene fragment (compounds 3 and 9-R in Schemes 1 and 3, respectively). This very simple and small caging group is the core element of a new class of masked rhodamines that have remarkable properties. The rhodamine NN dyes can be easily prepared and conjugated with biomolecules, they undergo rapid uncaging under standard irradiation conditions (with wavelengths 420 nm) with formation of highly fluorescent rhodamine derivatives, and they can be used in aqueous buffers, as well as in various embedding media utilized in imaging applications. In microscopy, these novel rhodamines may be used as labels alone or in combination with conventional fluorescent dyes and switchable rhodamine spiroamides. In the latter case, they enable new imaging protocols based on the stepwise activation and detection of several fluorescent markers. The combination of the new rhodamine NN derivative (9-R) with the photochromic spiroamide of rhodamine S and a normal (uncaged) N,N,N’,N’-tetramethylrhodamine resulted in a monochoromatic multilabel imaging scheme with low cross-talk, despite using three fluorophores with very similar absorption and emission spectra. Rhodamines are very photostable and bright fluorescent dyes which can readily be chemically modified and caged. Coumarines and fluorescein have also been used as caged fluorescent dyes. As a photocleavable unit, most of these caged compounds contain a 2-nitrobenzyl group or a derivative with an alkyl or a carboxy group in the a position to the phenyl ring (at the CH2 group) and/or one or two methoxy groups in the aromatic ring. Compounds with a free carboxy group are required for bioconjugation. However, the synthesis of caged rhodamines with a free (“second”) carboxy group is difficult and their yield is low. The 2-nitrobenzyl group and its substitutes are bulky and generate toxic, colored, and highly reactive 2-nitrosobenzaldehyde or 2-nitrosobenzophenone derivatives upon photolysis. These compounds or their oligomers are expected to be poisonous to living cells, and they are also colored and interfere with optical measurements. Other modern caging groups with the required absorption in the near-UV region are also bulky, rather lipophilic, and the procedures for their synthesis and introduction are often complex. For example, 2-(N,N-dimethylamino)-5-nitrophenol was reported to give photocleavable phenyl esters. 7-Diethylamino-4-(hydroxymethyl)-2H-chromen-2-one is known to form esters which can be cleaved easily by irradiation at 412 nm. Derivatives of 8-bromo-7-hydroxyquinoline and 6-bromo-7-hydroxycoumarines have also been proposed as light-sensitive protecting groups. The photolysis of these caged compounds generates light-absorbing by-products. We set out to prepare masked fluorescent dyes without bulky caging groups. A very small 2-diazoketone fragment would be an ideal caging group, provided that it is still possible to integrate this group into the colorless form of a fluorescent dye and then restore the fluorescent state by photolysis. Rhodamines are ideal for this purpose, because they contain a carboxy group, which is known to form colorless and nonfluorescent lactones or lactams with the spiro-9H-xanthene fragment. Furthermore, this carboxy group may be transformed into a 2-diazoketone residue. For the practical realization of this caging strategy, we used rhodamine B as a model compound and performed the reaction of diazomethane with its acid chloride 1. The yellow crystalline diazoketone 3 was obtained in high yield (Scheme 1). In the course of the facile caging reaction, the positively charged C9 atom of the xanthene fragment attacks the negatively charged carbon atom of the diazomethane residue in the intermediate 2. The simultaneous abstraction of a proton furnishes the stable five-membered ring. [*] Dr. V. N. Belov, Dr. C. A. Wurm, Dr. V. P. Boyarskiy, Dr. S. Jakobs, Prof. Dr. S. W. Hell Department of NanoBiophotonics Max Planck Institute for Biophysical Chemistry Am Fassberg 11, 37077 G ttingen (Germany) Fax: (+49)551-201-2506 E-mail: vbelov@gwdg.de cwurm@gwdg.de shell@gwdg.de Homepage: http://www.mpibpc.gwdg.de/abteilungen/200/

Vadim P. Boyarskiy

Papers

Metal-mediated and metal-catalyzed reactions of isocyanides.

Alkenylation of Arenes and Heteroarenes with Alkynes.

Multicolor Far-Field Fluorescence Nanoscopy through Isolated Detection of Distinct Molecular Species

Acyclic diaminocarbenes (ADCs) as a promising alternative to N-heterocyclic carbenes (NHCs) in transition metal catalyzed organic transformations

Rhodamines NN: A novel class of caged fluorescent dyes