Interference fringes with maximal contrast at finite coherence time

Interference fringes can result from the measurement of four-time fourth-order correlation functions of a wave field. These fringes have a statistical origin and, as a consequence, they show the greatest contrast when the coherence time of the field is finite. A simple acoustic experiment is presented in which these fringes are observed, and it is demonstrated that the contrast is maximal for partial coherence. Random telegraph phase noise is used to vary the field coherence in order to highlight the problem of interpreting this interference; for this noise, the Gaussian moment theorem may not be invoked to reduce the description of the interference to one in terms of first-order interference.M.W. Hamilto

Nucleic acid-based fluorescent probes and their analytical potential

It is well known that nucleic acids play an essential role in living organisms because they store and transmit genetic information and use that information to direct the synthesis of proteins. However, less is known about the ability of nucleic acids to bind specific ligands and the application of oligonucleotides as molecular probes or biosensors. Oligonucleotide probes are single-stranded nucleic acid fragments that can be tailored to have high specificity and affinity for different targets including nucleic acids, proteins, small molecules, and ions. One can divide oligonucleotide-based probes into two main categories: hybridization probes that are based on the formation of complementary base-pairs, and aptamer probes that exploit selective recognition of nonnucleic acid analytes and may be compared with immunosensors. Design and construction of hybridization and aptamer probes are similar. Typically, oligonucleotide (DNA, RNA) with predefined base sequence and length is modified by covalent attachment of reporter groups (one or more fluorophores in fluorescence-based probes). The fluorescent labels act as transducers that transform biorecognition (hybridization, ligand binding) into a fluorescence signal. Fluorescent labels have several advantages, for example high sensitivity and multiple transduction approaches (fluorescence quenching or enhancement, fluorescence anisotropy, fluorescence lifetime, fluorescence resonance energy transfer (FRET), and excimer-monomer light switching). These multiple signaling options combined with the design flexibility of the recognition element (DNA, RNA, PNA, LNA) and various labeling strategies contribute to development of numerous selective and sensitive bioassays. This review covers fundamentals of the design and engineering of oligonucleotide probes, describes typical construction approaches, and discusses examples of probes used both in hybridization studies and in aptamer-based assays

Analysis of the common genetic component of large-vessel vasculitides through a meta- Immunochip strategy

Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P?=?7.54E-07; ORGCA?=?1.19, ORTAK?=?1.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA?=?5.52E-04, ORGCA?=?1.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus

RevMexAA (Serie de Conferencias), 9, 238-245 (2000)

The Wisconsin H-Alpha Mapper (WHAM) has surveyed the entire northern sky in H from Kitt Peak, Arizona. Using a high-throughput, 15-cm diameter double-etalon Fabry-Perot spectrometer and a sensitive CCD detector, the WHAM survey provides the rst calibrated, velocity-resolved map of H emission in our Galaxy. A large portion of the Galaxy, which samples regions of the Local (Orion) spiral arm and the more distant Perseus arm, has been also been observed with the WHAM in lines of [S II] and [N II]. These new data directly probe the physical conditions of the Warm Ionized Medium (WIM) on a global scale for the rst time. Trends in these line ratios over this large region of the sky suggest that temperature variations are traced by the [N II]/H and [S II]/H maps. Since these ratios increase dramatically away from the Galactic plane, they reveal a substantial temperature rise in WIM halo gas. In addition to this striking new result, the data set also reveals new information about the ionization in the WIM through the [S II]/[N II] ratio, uncovers a previously undiscovered B-star H II region, and provides an accurate measurement of the electron scale height of the WIM

Transcriptional profiling of intrinsic PNS factors in the postnatal mouse

Neurons in the peripheral nervous system (PNS) display a higher capacity to regenerate after injury than those in the central nervous system, suggesting cell specific transcriptional modules underlying axon growth and inhibition. We report a systems biology based search for PNS specific transcription factors (TFs). Messenger RNAs enriched in dorsal root ganglion (DRG) neurons compared to cerebellar granule neurons (CGNs) were identified using subtractive hybridization and DNA microarray approaches. Network and transcription factor binding site enrichment analyses were used to further identify TFs that may be differentially active. Combining these techniques, we identified 32 TFs likely to be enriched and/or active in the PNS. Twenty-five of these TFs were then tested for an ability to promote CNS neurite outgrowth in an overexpression screen. Real-time PCR and immunohistochemical studies confirmed that one representative TF, STAT3, is intrinsic to PNS neurons, and that constitutively active STAT3 is sufficient to promote CGN neurite outgrowth