Calibration of Piping Assessment Models in the Netherlands

Flood Defenc

High-pressure Raman Study Of Zone-center Phonons In Pbtio3

A complete study of the k=0 optical phonons of the ferroelectric tetragonal PbTiO3 as a function of hydrostatic pressure has been carried out using Raman spectroscopy. The coalescence, to the same frequency, of the high-energy [A1(TO), E(TO)] pairs of phonons in the ferroelectric phase and the disappearance of the first-order Raman lines in the cubic phase has enabled us to determine the transition pressure Pc, as well as the second-order character of the phase transition. Our results also suggest the existence of a tricritical point in the (P,T) phase diagram. Using the Liddane-Sachs-Teller relation we calculate the static dielectric constant as a function of pressure and compare the results with previous dielectric measurements. Moreover, we discuss the soft phonons, their damping, and their behavior near the phase transition. It is found that the soft E(TO) phonon damping function is nearly constant over a wide frequency range and that it appears to diverge near the phase transition. © 1983 The American Physical Society.28127260726

Highly Parallel Acoustic Assembly of Microparticles into Well-Ordered Colloidal Crystallites

The precise arrangement of microscopic objects is critical to the development of functional materials and ornately patterned surfaces. Here, we present an acoustics-based method for the rapid arrangement of microscopic particles into organized and programmable architectures, which are periodically spaced within a square assembly chamber. This macroscale device employs two-dimensional bulk acoustic standing waves to propel particles along the base of the chamber toward pressure nodes or antinodes, depending on the acoustic contrast factor of the particle, and is capable of simultaneously creating thousands of size-limited, isotropic and anisotropic assemblies within minutes. We pair experiments with Brownian dynamics simulations to model the migration kinetics and assembly patterns of spherical microparticles. We use these insights to predict and subsequently validate the onset of buckling of the assemblies into three-dimensional clusters by experiments upon increasing the acoustic pressure amplitude and the particle concentration. The simulations are also used to inform our experiments for the assembly of non-spherical particles, which are then recovered via fluid evaporation and directly inspected by electron microscopy. This method for assembly of particles offers several notable advantages over other approaches (e.g., magnetics, electrokinetics and optical tweezing) including simplicity, speed and scalability and can also be used in concert with other such approaches for enhancing the types of assemblies achievable.Comment: 13 pages, 8 figure

Impact of Caffeine on Ethanol-Induced Stimulation and Sensitization: Changes in ERK and DARPP-32 Phosphorylation in Nucleus Accumbens

Background: Caffeine is frequently consumed with ethanol to reduce the impairing effects induced by ethanol, including psychomotor slowing or incoordination. Both drugs modulate dopamine (DA)-related markers in accumbens (Acb), and Acb DA is involved in voluntary locomotion and locomotor sensitization. The present study determined whether caffeine can affect locomotion induced by acute and repeated ethanol administration in adult male CD-1 mice. Methods: Acute administration of caffeine (7.5 to 30.0 mg/kg) was evaluated for its effects on acute ethanol-induced (1.5 to 3.5 g/kg) changes in open-field horizontal locomotion, supported rearing, and rearing not supported by the wall. DA receptor-dependent phosphorylation markers were assessed: extracellular signal-regulated kinase (pERK), and dopamine-and cAMP-regulated phosphoprotein Mr32kDa phosphorylated at threonine 75 site (pDARPP-32-Thr75) in Acb core and shell. Acutely administered caffeine was also evaluated in ethanol-sensitized (1.5 g/kg) mice. Results: Acute ethanol decreased both types of rearing. Caffeine increased supported rearing but did not block ethanol -induced decreases in rearing. Both substances increased horizontal locomotion in a biphasic manner, and caffeine potentiated ethanol-induced locomotion. Although ethanol administered repeatedly induced sensitization of locomotion and unsupported rearing, acute administration of caffeine to ethanol-sensitized mice in an ethanol-free state resulted in blunted stimulant effects compared with those seen in ethanol-naïve mice. Ethanol increased pERK immunoreactivity in both subregions of the Acb, but coadministration with caffeine blunted this increase. There were no effects on pDARPP-32(Thr75) immunoreactivity. Conclusions: The present results demonstrated that, after the first administration, caffeine potentiated the stimulating actions of ethanol, but did not counteract its suppressant or ataxic effects. Moreover, our results show that caffeine has less activating effects in ethanol-sensitized animals

Unsaturated fatty acids are inhibitors of bacterial conjugation

This report describes a high-throughput assay to identify substances that reduce the frequency of conjugation in Gram-negative bacteria. Bacterial conjugation is largely responsible for the spread of multiple antibiotic resistances in human pathogens. Conjugation inhibitors may provide a means to control the spread of antibiotic resistance. An automated conjugation assay was developed that used plasmid R388 and a laboratory strain of Escherichia coli as a model system, and bioluminescence as a reporter for conjugation activity. Frequencies of conjugation could be measured continuously in real time by the amount of light produced, and thus the effects of inhibitory compounds could be determined quantitatively. A control assay, run in parallel, allowed elimination of compounds affecting cell growth, plasmid stability or gene expression. The automated conjugation assay was used to screen a database of more than 12 000 microbial extracts known to contain a wide variety of bioactive compounds (the NatChem library). The initial hit rate was 1·4 %. From these, 48 extracts containing active compounds and representing a variety of organisms and extraction conditions were subjected to fractionation (24 fractions per extract). The 52 most active fractions were subjected to a secondary analysis to determine the range of plasmid inhibition. Plasmids R388, R1 and RP4 were used as representatives of a variety of plasmid transfer systems. Only one fraction (of complex composition) affected transfer of all three plasmids, while four other fractions were active against two of them. Two separate compounds were identified from these fractions: linoleic acid and dehydrocrepenynic acid. Downstream analysis showed that the chemical class of unsaturated fatty acids act as true inhibitors of conjugation

Ethanol and Caffeine Effects on Social Interaction and Recognition in Mice: Involvement of Adenosine A2A and A1 Receptors

Ethanol and caffeine are frequently consumed in combination and have opposite effects on the adenosine system: ethanol metabolism leads to an increase in adenosine levels, while caffeine is a non-selective adenosine A1/A2A receptor antagonist. These receptors are highly expressed in striatum and olfactory tubercle, brain areas involved in exploration and social interaction in rodents. Ethanol modulates social interaction processes, but the role of adenosine in social behavior is still poorly understood. The present work was undertaken to study the impact of ethanol, caffeine and their combination on social behavior, and to explore the involvement of A1 and A2A receptors on those actions. Male CD1 mice were evaluated in a social interaction three-chamber paradigm, for preference of conspecific vs. object, and also for long-term recognition memory of familiar vs. novel conspecific. Ethanol showed a biphasic effect, with low doses (0.25 g/kg) increasing social contact and higher doses (1.0-1.5 g/kg) reducing social interaction. However, no dose changed social preference; mice always spent more time sniffing the conspecific than the object, independently of the ethanol dose. Ethanol, even at doses that did not change social exploration, produced amnestic effects on social recognition the following day. Caffeine reduced social contact (15.0-60.0 mg/kg), and even blocked social preference at higher doses (30.0-60.0 mg/kg). The A1 antagonist Cyclopentyltheophylline (CPT; 3-9 mg/kg) did not modify social contact or preference on its own, and the A2A antagonist MSX-3 (1.5-6 mg/kg) increased social interaction at all doses. Ethanol at intermediate doses (0.5-1.0 g/kg) was able to reverse the reduction in social exploration induced by caffeine (15.0-30.0 mg/kg). Although there was no interaction between ethanol and CPT or MSX-3 on social exploration in the first day, MSX-3 blocked the amnestic effects of ethanol observed on the following day. Thus, ethanol impairs the formation of social memories, and A2A adenosine antagonists can prevent the amnestic effects of ethanol, so that animals can recognize familiar conspecifics. On the other hand, ethanol can counteract the social withdrawal induced by caffeine, a non-selective adenosine A1/A2A receptor antagonist. These results show the complex set of interactions between ethanol and caffeine, some of which could be the result of the opposing effects they have in modulating the adenosine system

Effects of Gamma Irradiation on Curcumin

In this study, remnants concentrations of curcumin in Curcuma longa (organic turmeric powder) were determined after it was exposed to irradiation doses of 1, 2 and 3 kGy. Curcumin analysis was performed using the analyte-sensitive impulse differential polarography technique (LOD: 0.621 ppm and LOQ: 2.130 ppm). The results obtained showed a decreasing concentration of curcumin as a function of the irradiation dose. This reduction is low in terms of affecting the product’s quality with respect to its concentration