A G protein is involved in the angiotensin AT2 receptor inhibition of the T-type calcium current in non-differentiated NG108-15 cells

In non-differentiated NG108-15 cells, both angiotensin II (Ang II) (100 nM) and CGP 42112 (100 nM) decreased the T-type calcium current amplitude by 24 +/- 2% and 21 +/- 3%, respectively. cGMP is not a mediator of the Ang II effect, since loading of cells with 50 microM cGMP did not prevent the inhibitory effects of Ang II. The effects of Ang II involves a non-identified GTPase activity since incubation with GDP beta S (3 mM) completely reversed the inhibitory effect of Ang II while GTP gamma S mimicked its effect. However, Ang II binding was not affected by GTP gamma S, and the effect of Ang II was not modified in pertussis toxin-treated cells. The inhibitory effect of Ang II on the T-type Ca2+ current involves a phosphotyrosine phosphatase activity since sodium orthovanadate prevented the effects of Ang II, although microcystin-LR, a selective Ser/Thr phosphatase 1 and 2A inhibitor, did not modify the effect of Ang II. These results provide the first evidence of a modulation of membrane conductance by Ang II through the AT2 receptor and demonstrate the involvement of a phosphotyrosine phosphatase and a G protein in the AT2 transduction mechanism in NG108-15 cells. Moreover, our data suggest that phosphotyrosine phosphatase activation is proximal to receptor occupation, since sodium orthovanadate inhibits both GTPase activity and T-type current blockage induced by Ang II or CGP 42112, while GTP gamma S inhibition of the T-type calcium current is not impaired.     

Simulating fermions on a quantum computer

The real-time probabilistic simulation of quantum systems in classical computers is known to be limited by the so-called dynamical sign problem, a problem leading to exponential complexity. In 1981 Richard Feynman raised some provocative questions in connection to the “exact imitation” of such systems using a special device named a “quantum computer”. Feynman hesitated about the possibility of imitating fermion systems using such a device. Here we address some of his concerns and, in particular, investigate the simulation of fermionic systems. We show how quantum computers avoid the sign problem in some cases by reducing the complexity from exponential to polynomial. Our demonstration is based upon the use of isomorphisms of algebras. We present specific quantum algorithms that illustrate the main points of our algebraic approach.     

The terminal O-acetyltransferase involved in vindoline biosynthesis defines a new class of proteins responsible for coenzyme A-dependent acyl transfer

The gene encoding acetyl CoA:deacetylvindoline 4-O-acetyltransferase (DAT) (EC 2.3.1.107) which catalyzes the last step in vindoline biosynthesis was isolated and characterized. The genomic clone encoded a 50 kDa polypeptide containing the sequences of nine tryptic fragments derived from the purified DAT heterodimer. However, cleavage of DAT protein to yield a heterodimer appears to be an artifact of the protein purification procedure, since the size of the protein (50 kDa) cross-reacting with anti-DAT antibody in seedlings and in leaves of various ages also corresponds to the size of the active recombinant enzyme. Studies with the intact plant and with developing seedlings showed that induction of DAT mRNA, protein accumulation and enzyme activity occurred preferentially in vindoline producing tissues such as leaves and cotyledons of light-treated etiolated seedlings. The ORF of DAT showed significant sequence identity to 19 other plant genes, whose biochemical functions were mostly unknown. The Mr of approximately 50 kDa, a HXXXDG triad, and a DFGWGKP consensus sequence are highly conserved among the 20 plant genes and these criteria may be useful to identify this type of acyltransferase. The involvement of some of these genes in epicuticular wax biosynthesis, fruit-ripening and in benzoyltransfer reactions indicates that the plant kingdom contains a superfamily of multifunctional acyltransferases which operate by a reaction mechanism related to the ancient chloramphenicol O-acetyltransferase and dihydrolipoyl acetyltransferase class of enzymes.     

The social patterning of injury repetitions among young car drivers in Sweden

A national register-based cohort study was conducted to explore whether the social patterning of car drivers suffering injury repetitions differs from that of once-injured drivers in a cohort of young persons in Sweden (aged 18-26). Injury repeaters were defined as individuals sustaining injuries as a car driver on more than one occasion over an 8-year period. Only subjects obtaining a driver's licence before the age of 27 were included in the study. The social variables considered were, in turn, gender, socioeconomic position of origin, and own educational attainment. Attention was also paid to age at licensing. Two types of comparisons were made, using odds ratios with 95% confidence intervals. First, the odds of injury repeaters were computed using the once-injured car drivers as a reference group. Second, odds were compiled for once, twice, and three or more times injured people, using the non-injured at all as a comparison group. The results show that, by and large, the injury-risk distribution of car drivers with injury repetition does not differ from that of one-injury drivers with regard to gender, education, or socioeconomic group. However, drivers from self-employed households show greater odds of injury repetition (OR 1.65, CI 1.02-2.67) than of one injury compared with drivers from the families of non-manual employees. Since the number of injury repeaters is low and their socioeconomic distribution is very similar to that of the once injured, there is no need to regard them as a group at excess risk or different from the one-time injured. Reducing risk levels and risk differentials for the one time injured should therefore receive priority with regard to traffic-injury prevention.     

Economic and environmental assessment on the energetic valorization of organic material for a municipality in Quebec, Canada

Waste-to-energy provides a solution to two problems: waste management and energy generation. An integrated anaerobic waste valorization process is an interesting option, but because of investments cost and low energy value in the province of Quebec, it is hard for a municipality to commit to that solution. This paper investigated the economic possibilities to manage organic material, organic fraction of municipal solid waste, and municipal wastewater sludge by anaerobic digestion for a 150,000 inhabitant municipality, with consideration to energy generation and greenhouse gas emission reduction. Using the biogas to co-generation solution brings a payback time on investment (PBT) of 3.7 years with electricity price at 0.10 $Cdn/kW h. The addition of manure from surrounding farms increases the biogas production by 37%, but increases the PBT to 6.8 years unless the leftover digestate can be used for agronomic valorization; then it becomes economically advantageous. The natural gas purchasing cost is too low to promote the enrichment of biogas into renewable natural gas. However, this scenario has the lowest energetic payback time (3.3 years) and reduces the most greenhouse gas emissions (4261 tCO₂eq/a).     

Distribution and characteristics of road traffic crashes in the Chaoyang District of Beijing, China

In many developing urban settings, economic growth and motorization are coupled with increasing rates of road traffic injuries (RTIs). By highlighting typical sites and circumstances at/in which car crashes occur, more specific targets for prevention can be identified. The study is based on police data for a 1-year period and covers the Chaoyang District, the biggest district of Beijing City. Focus is placed on crash patterns and their distribution by types of road and areas. Both fatal and non-fatal crashes are considered (n=754). In the main, the crashes occurred in relatively favorable driving circumstances (e.g., sunny weather, flat and straight roads, asphalted roads, and good traffic signals and road markings). They were also quite evenly distributed over time of day, day of week and season. Five crash patterns were highlighted, of which three were strongly associated with specific areas and four with specific types of road. The study supports the idea that type of road and RTI severity or pattern are closely related. It contributes to the development of context-relevant prevention measures aimed at reducing road crashes and minimizing their consequences and also supports safe planning of the road traffic environment.     

Wavelet Network for Semi-Active Control

This paper proposes a wavelet neurocontroller capable of self-adaptation and self-organization for uncertain systems controlled with semiactive devices that are ideal candidates for control of large-scale civil structures. A condition on the sliding surface for cantilever-like structures is defined. The issue of applicability of the control solution to large-scale civil structures is made the central theme throughout the text, as this topic has not been extensively discussed in the literature. Stability and convergence of the proposed neurocontroller are assessed through various numerical simulations for harmonic, earthquake, and wind excitations. The simulations consist of semiactive dampers installed as a replacement for the current viscous damping system in an existing structure. The controller uses only localized measurements. Results show that the controller is stable for both active and semiactive control using limited measurements and that it is capable of outperforming passive control strategies for earthquake and wind loads. In the case of wind loads, the neurocontroller is found to also outperform a linear quadratic regulator (LQR) controller designed using full knowledge of the states and system dynamics.