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Quantum control of energy flow in light harvesting 总被引:8,自引:0,他引:8
Coherent light sources have been widely used in control schemes that exploit quantum interference effects to direct the outcome of photochemical processes. The adaptive shaping of laser pulses is a particularly powerful tool in this context: experimental output as feedback in an iterative learning loop refines the applied laser field to render it best suited to constraints set by the experimenter. This approach has been experimentally implemented to control a variety of processes, but the extent to which coherent excitation can also be used to direct the dynamics of complex molecular systems in a condensed-phase environment remains unclear. Here we report feedback-optimized coherent control over the energy-flow pathways in the light-harvesting antenna complex LH2 from Rhodopseudomonas acidophila, a photosynthetic purple bacterium. We show that phases imprinted by the light field mediate the branching ratio of energy transfer between intra- and intermolecular channels in the complex's donor acceptor system. This result illustrates that molecular complexity need not prevent coherent control, which can thus be extended to probe and affect biological functions. 相似文献
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A functional variant of SUMO4, a new I kappa B alpha modifier, is associated with type 1 diabetes 总被引:23,自引:0,他引:23
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Itatani J Levesque J Zeidler D Niikura H Pépin H Kieffer JC Corkum PB Villeneuve DM 《Nature》2004,432(7019):867-871
Single-electron wavefunctions, or orbitals, are the mathematical constructs used to describe the multi-electron wavefunction of molecules. Because the highest-lying orbitals are responsible for chemical properties, they are of particular interest. To observe these orbitals change as bonds are formed and broken is to observe the essence of chemistry. Yet single orbitals are difficult to observe experimentally, and until now, this has been impossible on the timescale of chemical reactions. Here we demonstrate that the full three-dimensional structure of a single orbital can be imaged by a seemingly unlikely technique, using high harmonics generated from intense femtosecond laser pulses focused on aligned molecules. Applying this approach to a series of molecular alignments, we accomplish a tomographic reconstruction of the highest occupied molecular orbital of N2. The method also allows us to follow the attosecond dynamics of an electron wave packet. 相似文献
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Profile identification of disease-associated humoral antigens using AMIDA, a novel proteomics-based technology 总被引:1,自引:0,他引:1
Gires O Münz M Schaffrik M Kieu C Rauch J Ahlemann M Eberle D Mack B Wollenberg B Lang S Hofmann T Hammerschmidt W Zeidler R 《Cellular and molecular life sciences : CMLS》2004,61(10):1198-1207
We describe AMIDA (autoantibody-mediated identification of antigens), a novel target identification technology based on the immunoprecipitation of disease-specific antigens by autologous serum antibodies followed by two-dimensional electrophoretic separation, and their identification via mass spectrometry. Twenty-seven potential carcinoma antigens were identified including proteins of hitherto unknown function. Validation of one of the identified antigens, cytokeratin 8, revealed its de novo expression in hyperplastic tissue, gradual overexpression with increasing malignancy, and ectopic localization on the cell surface. Furthermore, a strong prevalence of CK8-specific antibodies occurred in the serum of cancer patients already at early disease stages. In situ hybridization for one marker of unknown function, KIAA1273/TOB3, demonstrated its strong overexpression in head and neck carcinomas, thus making it a likely tumor antigen candidate. Eventually, AMIDA could foster significant improvements for the diagnosis and therapy of human diseases eliciting a humoral immune response, and allows for the rapid identification of new target molecules.Received 30 January 2004; received after revision 3 March 2004; accepted 8 March 2004 相似文献
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Klein C Grudzien M Appaswamy G Germeshausen M Sandrock I Schäffer AA Rathinam C Boztug K Schwinzer B Rezaei N Bohn G Melin M Carlsson G Fadeel B Dahl N Palmblad J Henter JI Zeidler C Grimbacher B Welte K 《Nature genetics》2007,39(1):86-92
Autosomal recessive severe congenital neutropenia (SCN) constitutes a primary immunodeficiency syndrome associated with increased apoptosis in myeloid cells, yet the underlying genetic defect remains unknown. Using a positional cloning approach and candidate gene evaluation, we identified a recurrent homozygous germline mutation in HAX1 in three pedigrees. After further molecular screening of individuals with SCN, we identified 19 additional affected individuals with homozygous HAX1 mutations, including three belonging to the original pedigree described by Kostmann. HAX1 encodes the mitochondrial protein HAX1, which has been assigned functions in signal transduction and cytoskeletal control. Here, we show that HAX1 is critical for maintaining the inner mitochondrial membrane potential and protecting against apoptosis in myeloid cells. Our findings suggest that HAX1 is a major regulator of myeloid homeostasis and underline the significance of genetic control of apoptosis in neutrophil development. 相似文献
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