Revisiting Street Intersections Using Slot-Based Systems

Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs). Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities.     

Genotypic diversity of oscillatoriacean strains belonging to the genera Geitlerinema and Spirulina determined by 16S rDNA restriction analysis

Genotypic diversity of several cyanobacterial strains mostly isolated from marine or brackish waters, belonging to the genera Geitlerinema and Spirulina, was investigated by amplified 16S ribosomal DNA restriction analysis and compared with morphological features and response to salinity. Cluster analysis was performed on amplified 16S rDNA restriction profiles of these strains along with profiles obtained from sequence data of five Spirulina-like strains, including three representatives of the new genus Halospirulina. Our strains with tightly coiled trichomes from hypersaline waters could be assigned to the Halospirulina genus. Among the uncoiled strains, the two strains of hypersaline origin clustered together and were found to be distant from their counterparts of marine and freshwater habitat. Moreover, another cluster, formed by alkali-tolerant strains with tightly coiled trichomes, was well delineated.     

A 5' splice site-proximal enhancer binds SF1 and activates exon bridging of a microexon

Internal exon size in vertebrates occurs over a narrow size range. Experimentally, exons shorter than 50 nucleotides are poorly included in mRNA unless accompanied by strengthened splice sites or accessory sequences that act as splicing enhancers, suggesting steric interference between snRNPs and other splicing factors binding simultaneously to the 3' and 5' splice sites of microexons. Despite these problems, very small naturally occurring exons exist. Here we studied the factors and mechanism involved in recognizing a constitutively included six-nucleotide exon from the cardiac troponin T gene. Inclusion of this exon is dependent on an enhancer located downstream of the 5' splice site. This enhancer contains six copies of the simple sequence GGGGCUG. The enhancer activates heterologous microexons and will work when located either upstream or downstream of the target exon, suggesting an ability to bind factors that bridge splicing units. A single copy of this sequence is sufficient for in vivo exon inclusion and is the binding site for the known bridging mammalian splicing factor 1 (SF1). The enhancer and its bound SF1 act to increase recognition of the upstream exon during exon definition, such that competition of in vitro reactions with RNAs containing the GGGGCUG repeated sequence depress splicing of the upstream intron, assembly of the spliceosome on the 3' splice site of the exon, and cross-linking of SF1. These results suggest a model in which SF1 bridges the small exon during initial assembly, thereby effectively extending the domain of the exon.     

Structure and localization of an essential transmembrane segment of the proton translocation channel of yeast H+-V-ATPase

Vacuolar (H+)-ATPase (V-ATPase) is a proton pump present in several compartments of eukaryotic cells to regulate physiological processes. From biochemical studies it is known that the interaction between arginine 735 present in the seventh transmembrane (TM7) segment from subunit a and specific glutamic acid residues in the subunit c assembly plays an essential role in proton translocation. To provide more detailed structural information about this protein domain, a peptide resembling TM7 (denoted peptide MTM7) from Saccharomyces cerevisiae (yeast) V-ATPase was synthesized and dissolved in two membrane-mimicking solvents: DMSO and SDS. For the first time the secondary structure of the putative TM7 segment from subunit a is obtained by the combined use of CD and NMR spectroscopy. SDS micelles reveal an alpha-helical conformation for peptide MTM7 and in DMSO three alpha-helical regions are identified by 2D 1H-NMR. Based on these conformational findings a new structural model is proposed for the putative TM7 in its natural environment. It is composed of 32 amino acid residues that span the membrane in an alpha-helical conformation. It starts at the cytoplasmic side at residue T719 and ends at the luminal side at residue W751. Both the luminal and cytoplasmatic regions of TM7 are stabilized by the neighboring hydrophobic transmembrane segments of subunit a and the subunit c assembly from V-ATPase.     

Mda-9/syntenin is expressed in uveal melanoma and correlates with metastatic progression

Uveal melanoma is an aggressive cancer that metastasizes to the liver in about half of the patients, with a high lethality rate. Identification of patients at high risk of metastases may provide indication for a frequent follow-up for early detection of metastases and treatment. The analysis of the gene expression profiles of primary human uveal melanomas showed high expression of SDCBP gene (encoding for syndecan-binding protein-1 or mda-9/syntenin), which appeared higher in patients with recurrence, whereas expression of syndecans was lower and unrelated to progression. Moreover, we found that high expression of SDCBP gene was related to metastatic progression in two additional independent datasets of uveal melanoma patients. More importantly, immunohistochemistry showed that high expression of mda-9/syntenin protein in primary tumors was significantly related to metastatic recurrence in our cohort of patients. Mda-9/syntenin expression was confirmed by RT-PCR, immunofluorescence and immunohistochemistry in cultured uveal melanoma cells or primary tumors. Interestingly, mda-9/syntenin showed both cytoplasmic and nuclear localization in cell lines and in a fraction of patients, suggesting its possible involvement in nuclear functions. A pseudo-metastatic model of uveal melanoma to the liver was developed in NOD/SCID/IL2Rγ null mice and the study of mda-9/syntenin expression in primary and metastatic lesions revealed higher mda-9/syntenin in metastases. The inhibition of SDCBP expression by siRNA impaired the ability of uveal melanoma cells to migrate in a wound-healing assay. Moreover, silencing of SDCBP in mda-9/syntenin-high uveal melanoma cells inhibited the hepatocyte growth factor (HGF)-triggered invasion of matrigel membranes and inhibited the activation of FAK, AKT and Src. Conversely syntenin overexpression in mda-9/syntenin-low uveal melanoma cells mediated opposite effects. These results suggest that mda-9/syntenin is involved in uveal melanoma progression and that it warrants further investigation as a candidate molecular marker of metastases and a potential therapeutic target.     

Determination of picotamide in human plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of picotamide in human plasma and urine is described. After addition of an internal standard (bamifylline), the plasma and urine samples were subjected to liquid—liquid extraction and clean-up procedures. The final extracts were evaporated to dryness and the resulting residues were reconstituted in 100 μl of methanol—water (50:50, v/v) and chromatographed on a LiChrosorb RP-SELECT B reversed-phase column coupled to an ultraviolet detector monitored at 230 nm. Chromatographic analysis takes about 10 min per sample. The assay was linear over a wide range and has a limit of detection of 0.005 and 0.1 μg/ml in plasma and urine, respectively. It was selective for picotamide, accurate and robust and thus suitable for routine assays after therapeutic doses of picotamide.     

New records of deep-sea decapod crustaceans in the Turkish Mediterranean Sea (North Levant Sea)

A survey of the bathyal trawling grounds in the Gulf of Antalya (Turkish Mediterranean Sea) yielded 34 species of decapod crustaceans. Four species (Funchalia villosa, Plesionika acanthonotus, P. gigliolii, Monodaeus couchii) are recorded for the first time from the Levant Sea. The number of marine decapod species reported for Turkey rises to 265 and the number reported from the Turkish Mediterranean Sea to 211.     

Causal mechanisms underlying host specificity in bat ectoparasites

In parasites, host specificity may result either from restricted dispersal capacity or from fixed coevolutionary host-parasite adaptations. Knowledge of those proximal mechanisms leading to particular host specificity is fundamental to understand host-parasite interactions and potential coevolution of parasites and hosts. The relative importance of these two mechanisms was quantified through infection and cross-infection experiments using mites and bats as a model. Monospecific pools of parasitic mites (Spinturnix myoti and S. andegavinus) were subjected either to individual bats belonging to their traditional, native bat host species, or to another substitute host species within the same bat genus (Myotis). The two parasite species reacted differently to these treatments. S. myoti exhibited a clear preference for, and had a higher fitness on, its native host, Myotis myotis. In contrast, S. andegavinus showed no host choice, although its fitness was higher on its native host M. daubentoni. The causal mechanisms mediating host specificity can apparently differ within closely related host-parasite systems.     

Vegetative versus Minimally Conscious States: A Study Using TMS-EEG,Sensory and Event-Related Potentials

Differential diagnoses between vegetative and minimally conscious states (VS and MCS, respectively) are frequently incorrect. Hence, further research is necessary to improve the diagnostic accuracy at the bedside. The main neuropathological feature of VS is the diffuse damage of cortical and subcortical connections. Starting with this premise, we used electroencephalography (EEG) recordings to evaluate the cortical reactivity and effective connectivity during transcranial magnetic stimulation (TMS) in chronic VS or MCS patients. Moreover, the TMS-EEG data were compared with the results from standard somatosensory-evoked potentials (SEPs) and event-related potentials (ERPs). Thirteen patients with chronic consciousness disorders were examined at their bedsides. A group of healthy volunteers served as the control group. The amplitudes (reactivity) and scalp distributions (connectivity) of the cortical potentials evoked by TMS (TEPs) of the primary motor cortex were measured. Short-latency median nerve SEPs and auditory ERPs were also recorded. Reproducible TEPs were present in all control subjects in both the ipsilateral and the contralateral hemispheres relative to the site of the TMS. The amplitudes of the ipsilateral and contralateral TEPs were reduced in four of the five MCS patients, and the TEPs were bilaterally absent in one MCS patient. Among the VS patients, five did not manifest ipsilateral or contralateral TEPs, and three of the patients exhibited only ipsilateral TEPs with reduced amplitudes. The SEPs were altered in five VS and two MCS patients but did not correlate with the clinical diagnosis. The ERPs were impaired in all patients and did not correlate with the clinical diagnosis. These TEP results suggest that cortical reactivity and connectivity are severely impaired in all VS patients, whereas in most MCS patients, the TEPs are preserved but with abnormal features. Therefore, TEPs may add valuable information to the current clinical and neurophysiological assessment of chronic consciousness disorders.