23 research outputs found
Systemanalytische Einführung in die kommerzielle EDV - Problemlösen mit COBOL
Spitta T, Gasch B, Franck H. Systemanalytische Einführung in die kommerzielle EDV - Problemlösen mit COBOL. Berlin - New York: DeGruyter; 1979
Chlorophyll fluorescence emission spectrum inside a leaf
Chlorophyll a fluorescence can be used as an early stress indicator. Fluorescence is also connected to photosynthesis so it can be proposed for global monitoring of vegetation status from a satellite platform. Nevertheless, the correct interpretation of fluorescence requires accurate physical models. The spectral shape of the leaf fluorescence free of any re-absorption effect plays a key role in the models and is difficult to measure. We present a vegetation fluorescence emission spectrum free of re-absorption based on a combination of measurements and modelling. The suggested spectrum takes into account the photosystem I and II spectra and their relative contribution to fluorescence. This emission spectrum is applicable to describe vegetation fluorescence in biospectroscopy and remote sensing
Sex- and Gender-Based Pharmacological Response to Drugss
In humans, the combination of all sex-specific genetic, epigenetic, and hormonal influences of biologic sex produces different in vivo environments for male and female cells. We dissect how these influences of sex modify the pharmacokinetics and pharmacodynamics of multiple drugs and provide examples for common drugs acting on specific organ systems. We also discuss how gender of physicians and patients may influence the therapeutic response to drugs. We aim to highlight sex as a genetic modifier of the pharmacological response to drugs, which should be considered as a necessary step toward precision medicine that will benefit men and women. Significance Statement-This study discusses the influences of biologic sex on the pharmacokinetics and pharmacodynamics of drugs and provides examples for common drugs acting on specific organ systems. This study also discusses how gender of physicians and patients influence the therapeutic response to drugs
Moving Forward with Metronomic Chemotherapy: Meeting Report of the 2nd International Workshop on Metronomic and Anti-Angiogenic Chemotherapy in Paediatric Oncology
Metronomic chemotherapy, which is defined by the frequent, repetitive administration of chemotherapeutic drugs at relatively low doses, and without prolonged drug-free break, is an emerging strategy to fight cancer. Initially thought to act by targeting tumor angiogenesis, additional mechanisms have been recently unveiled, and metronomic chemotherapy is now considered to represent a form of multitargeted therapy. Despite representing a genuine alternative for advanced and/or high-risk cancer therapy, the development of metronomic approaches in pediatric oncology is still in the early stage. The few numbers of large-scale state-of-the-art clinical trials, issues regarding terminology and the limited understanding of the complex and intertwined mechanisms of action of metronomic treatments have limited progress in this important field of research. On March 18 and 19, 2010, the 2nd International Workshop on Metronomic and Anti-Angiogenic Chemotherapy in Paediatric Oncology was held in Marseille, France, and brought together clinicians, basic scientists, physician-scientists, trainees, and students from all around the world. The main aim of this international meeting was to provide a unique forum to 1) reflect on the major advances that have been made in this field of research since its creation, 2) communicate results from the most recent clinical trials and preclinical studies, 3) discuss the current and future challenges of the field, and 4) set forth a solid framework for future collaborative biologic and clinical studies. The present report documents the main preclinical and clinical data that were presented in the keynote and best abstract sessions and delivers the key messages from the meeting
Resolution of the Photosystem I and Photosystem II contributions to chlorophyll fluorescence of intact leaves at room temperature
Green leaves illuminated with photosynthetically active light emit red fluorescence, whose time-dependent intensity variations reflect photosynthetic electron transport (the Kautsky effect). Usually, fluorescence variations are discussed by considering only the contribution of PSII-associated chlorophyll a, although it is known that the fluorescence of PSI-associated chlorophyll a also contributes to the total fluorescence [Aust. J. Plant Physiol. 22 (1995) 13 1]. Because the fluorescence emitted by each photosystem cannot be measured separately by selecting the emission wavelength in in vivo conditions, the contribution of PSI to total fluorescence at room temperature is still in ambiguity. By using a diode array detector, we measured fluorescence emission spectra corresponding to the minimal (F-O) and maximal (F-M) fluorescence states. We showed that the different shapes of these spectra were mainly due to a higher contribution of PSI chlorophylls in the F-O spectrum. By exciting PSI preferentially, we recorded a reference PSI emission spectrum in the near far-red region. From the F-O and F-M spectra and from this PSI reference spectrum, we derived specific PSI and PSII emission spectra in both the F-O and F-M states. This enables to estimate true value of the relative variable fluorescence of PSII, which was underestimated in previous works. Accurate separation of PSI-PSII fluorescence emission spectra will also enable further investigations of the distribution of excitation energy between PSI and PSII under in vivo conditions. (C) 2002 Elsevier Science B.V. All rights reserved
A type II NAD(P)H dehydrogenase mediates light-independent plastoquinone reduction in the chloroplast of Chlamydomonas
In photosynthetic eukaryotes, nonphotochemical plastoquinone (PQ) reduction is important for the regulation of photosynthetic electron flow. In green microalgae where this process has been demonstrated, the chloroplastic enzyme that catalyses nonphotochemical PQ reduction has not been identified yet. Here, we show by an RNA interference (RNAi) approach that the NDA2 gene, belonging to a type II NAD(P)H dehydrogenases family in the green microalga Chlamydomonas reinhardtii, encodes a chloroplastic dehydrogenase that functions to reduce PQ nonphotochemically in this alga. Using a specific antibody, we show that the Nda2 protein is localized in chloroplasts of wild-type cells and is absent in two Nda2-RNAi cell lines. In both mutant cell lines, nonphotochemical PQ reduction is severely affected, as indicated by altered chlorophyll fluorescence transients after saturating illumination. Compared with wild type, change in light excitation distribution between photosystems ('state transition') upon inhibition of mitochondrial electron transport is strongly impaired in transformed cells because of inefficient PQ reduction. Furthermore, the amount of hydrogen produced by Nda2-RNAi cells under sulfur deprivation is substantially decreased compared with wild type, which supports previous assumptions that endogenous substrates serve as source of electrons for hydrogen formation. These results demonstrate the importance of Nda2 for nonphotochemical PQ reduction and associated processes in C. reinhardtii.Micro-H