Neutral and Charged 1-Butyl-3-methylimidazolium Triflate Clusters: Equilibrium Concentration in the Vapor Phase and Thermal Properties of Nanometric Droplets

Ground state energy, structure, and harmonic vibrational modes of 1-butyl-3-methylimidazolium triflate ([bmim][Tf]) clusters have been computed using an all-atom empirical potential model. Neutral and charged species have been considered up to a size (30 [bmim][Tf] pairs) well into the nanometric range. Free energy computations and thermodynamic modeling have been used to predict the equilibrium composition of the vapor phase as a function of temperature and density. The results point to a nonnegligible concentration of very small charged species at pressures (P ~ 0.01 Pa) and temperatures (T 600 K) at the boundary of the stability range of [bmim][Tf]. Thermal properties of nanometric neutral droplets have been investigated in the 0 T 700 K range. A near-continuous transition between a liquidlike phase at high T and a solidlike phase at low T takes place at T ~ 190 K in close correspondence with the bulk glass point Tg ~ 200 K. Solidification is accompanied by a transition in the dielectric properties of the droplet, giving rise to a small permanent dipole embedded into the solid cluster. The simulation results highlight the molecular precursors of several macroscopic properties and phenomena and point to the close competition of Coulomb and dispersion forces as their common origin.

Elements of the granular gland peptidome and transcriptome persist in air-dried skin of the South American orange-legged leaf frog, Phyllomedusa hypocondrialis.

The defensive strategy of amphibians against predator attack relies heavily on the secretion of noxious/toxic chemical cocktails from specialized skin granular glands. Bioactive peptides constitute a major component of secretions in many species and the most complex are produced by neotropical leaf frogs of the sub-family Phyllomedusinae. We recently reported that these skin secretions contain elements of both the granular gland peptidome and transcriptome and that polyadenylated mRNAs constituting the latter are protected from degradation by interactions with endogenous amphipathic peptides. This thus permits parallel amino acid sequencing of peptides and nucleic acid sequencing of cloned precursor transcripts from single lyophilized samples of secretion. Here we report that the protection afforded is sufficiently robust to permit transcriptome studies by cloning of full-length polyadenylated peptide precursor encoding mRNAs from libraries constructed using ambient temperature air-dried skin from recently deceased specimens as source material. The technique was sufficiently sensitive to permit the identification of cDNAs encoding antimicrobial peptides constituted by six different isoforms of phylloseptin and two dermaseptins. Also, for the first time, establishment of the nucleic acid and amino acid sequence of the precursor encoding the phyllomedusine frog skin bradykinin-related peptide, phyllokinin, from cloned cDNA, was achieved. These data unequivocally demonstrate that the granular gland transcriptome persists in air-dried amphibian skin—a finding that may have fundamental implications in the study of archived materials but also in the wider field of molecular biology.

Simulation of coupled heat and moisture transfer in air-conditioned buildings

The simultaneous heat and moisture transfer in the building envelope has an important influence on the indoor environment and the overall performance of buildings. In this paper, a model for predicting whole building heat and moisture transfer was presented. Both heat and moisture transfer in the building envelope and indoor air were simultaneously considered; their interactions were modeled. The coupled model takes into account most of the main hygrothermal effects in buildings. The coupled system model was implemented in MATLAB-Simulink, and validated by using a series of published testing tools. The new program was applied to investigate the moisture transfer effect on indoor air humidity and building energy consumption under different climates. The results show that the use of more detailed simulation routines can result in improvements to the building's design for energy optimisation through the choice of proper hygroscopic materials, which would not be indicated by simpler calculation techniques.

Wealth concentration in the European periphery: Ireland, 1858–2001

Using annual will indexes, a series of wealth concentration is constructed for the north of Ireland on a decennial basis for the period 1858 to 2001. Wealth was highly concentrated at the beginning of the sample period, but inequality falls towards the end of the nineteenth century and continues to fall until the 1970s. However, there does not appear to be a Kuznets-type process at work. Instead, using data on socio-occupational status, it is suggested that the fall in wealth concentration appears to be associated with the demise of the titled classes. Interestingly, similar to the findings of other studies, wealth has become more concentrated since the 1970s.

An Investigation into the Dissolution Properties of Celecoxib Melt Extrudates: Understanding the Role of Polymer Type and Concentration in Stabilizing Supersaturated Drug Concentrations

In this study, the dissolution properties of celecoxib (CX) solid dispersions manufactured from Eudragit 4155F and polyvinylpyrrolidone (PVP) were evaluated. Hot-melt extrusion (HME) technology was used to prepare amorphous solid dispersions of drug/polymer binary systems at different mass ratios. The drug concentrations achieved from the dissolution of PVP and Eudragit 4155F solid dispersions in phosphate buffer, pH 7.4 (PBS 7.4) were significantly greater than the equilibrium solubility of CX (1.58 µg/mL). The degree of supersaturation increased significantly as the polymer concentration within the solid dispersion increased. The maximum drug concentration achieved by PVP solid dispersions did not significantly exceed the apparent solubility of amorphous CX. The predominant mechanism for achieving supersaturated CX concentrations in PBS 7.4 was attributed to stabilization of amorphous CX during dissolution. Conversely, Eudragit 4155F solid dispersions showed significantly greater supersaturated drug solutions particularly at high polymer concentrations. For example, at a drug/polymer ratio of 1:9, a concentration of 100 µg/mL was achieved after 60 min that was stable (no evidence of drug recrystallization) for up to 72 h. This clearly identifies the potential of Eudragit 4155F to act as a solubilizing agent for CX. These findings were in good agreement with the results from solubility performed using PBS 7.4 in which Eudragit 4155F had been predissolved. In these tests, Eudragit 4155F significantly increased the equilibrium solubility of CX. Solution 1H NMR spectra were used to identify drug/polymer interactions. Deshielding of CX aromatic protons (H-1a and H-1b) containing the sulfonamide group occurred as a result of dissolution of Eudragit 4155F solid dispersions, whereas deshielding of H-1a protons and shielding of H-1b protons occurred as a result of the dissolution of PVP solid dispersions. In principle, it is reasonable to suggest that the different drug/polymer interactions observed give rise to the variation in dissolution observed for the two polymer/drug systems.

Apolipoprotein E polymorphism and serum concentration in Alzheimer's disease in nine European centres:the ApoEurope study. ApoEurope group

As part of the ApoEurope Project, apolipoprotein E (apo E) common polymorphism and serum concentration were determined in 489 Alzheimer's disease patients and 429 controls. Patients and controls were recruited through nine centres in eight European countries. Age, sex ratios and education levels of both case and control populations were similar, although discrete differences appeared between centres. The prevalence of the epsilon4 allele was higher in Alzheimer's disease than in controls (increased by 140%), while serum apo E concentration was lower by 11.2% (p

Variation in arsenic speciation and concentration in Paddy Rice related to Dietary Exposure

Ingestion of drinking water is not the only elevated source of arsenic to the diet in the Bengal Delta. Even at background levels, the arsenic in rice contributes considerably to arsenic ingestion in subsistence rice diets. We set out to survey As speciation in different rice varieties from different parts of the globe to understand the contribution of rice to arsenic exposure. Pot experiments were utilized to ascertain whether growing rice on As contaminated soil affected speciation and whether genetic variation accounted for uptake and speciation. USA long grain rice had the highest mean arsenic level in the grain at 0.26 µg As g-1 (n = 7), and the highest grain arsenic value of the survey at 0.40 µg As g-1. The mean arsenic level of Bangladeshi rice was 0.13 µg As g-1 (n = 15). The main As species detected in the rice extract were AsIII, DMAV, and AsV. In European, Bangladeshi, and Indian rice 64 ± 1% (n = 7), 80 ± 3% (n = 11), and 81 ± 4% (n = 15), respectively, of the recovered arsenic was found to be inorganic. In contrast, DMAV was the predominant species in rice from the USA, with only 42 ± 5% (n = 12) of the arsenic being inorganic. Pot experiments show that the proportions of DMAV in the grain are significantly dependent on rice cultivar (p = 0.026) and that plant nutrient status is effected by arsenic exposure. Ingestion of drinking water is not the only elevated source of arsenic to the diet in the Bengal Delta. Even at background levels, the arsenic in rice contributes considerably to arsenic ingestion in subsistence rice diets. We set out to survey As speciation in different rice varieties from different parts of the globe to understand the contribution of rice to arsenic exposure. Pot experiments were utilized to ascertain whether growing rice on As contaminated soil affected speciation and whether genetic variation accounted for uptake and speciation. USA long grain rice had the highest mean arsenic level in the grain at 0.26 µg As g-1 (n = 7), and the highest grain arsenic value of the survey at 0.40 µg As g-1. The mean arsenic level of Bangladeshi rice was 0.13 µg As g-1 (n = 15). The main As species detected in the rice extract were AsIII, DMAV, and AsV. In European, Bangladeshi, and Indian rice 64 ± 1% (n = 7), 80 ± 3% (n = 11), and 81 ± 4% (n = 15), respectively, of the recovered arsenic was found to be inorganic. In contrast, DMAV was the predominant species in rice from the USA, with only 42 ± 5% (n = 12) of the arsenic being inorganic. Pot experiments show that the proportions of DMAV in the grain are significantly dependent on rice cultivar (p = 0.026) and that plant nutrient status is effected by arsenic exposure.

Investigation of organic xenobiotic transfers, partitioning and processing in air-soil-plant systems using a microcosm apparatus. Part II:comparing the fate of chlorobenzenes in grass planted soil

A microcosm system was used to investigate and compare transfers of 14C labeled-1,2-dichlorobenzene (DCB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB) in an air-soil-plant system using single grass tillers planted into spiked soil. This study was the second phase of a development investigation for eventual study of a range of xenobiotic pollutants. Recoveries from the system were excellent at >90%. The predominant loss pathway for 14C labeled-1,2-DCB and 1,2,4-TCB was volatilisation with 85% and 76% volatilisation of parent compound and volatile metabolites over 5 weeks respectively. Most of the added label in the hexachlorobenzene spiked system remained in soil. Mineralisation was

Field and Laboratory Tests of Flow-Proportional Passive Samplers for Determining Average Phosphorus and Nitrogen Concentration in Rivers

Flow responsive passive samplers offer considerable potential in nutrient monitoring in catchments; bridging the gap between the intermittency of grab sampling and the high cost of automated monitoring systems. A commercially available passive sampler was evaluated in a number of river systems encapsulating a gradient in storm response, combinations of diffuse and point source pressures, and levels of phosphorus and nitrogen concentrations. Phosphorus and nitrogen are sequestered to a resin matrix in a permeable cartridge positioned in line with streamflow. A salt tracer dissolves in proportion to advective flow through the cartridge. Multiple deployments of different cartridge types were undertaken and the recovery of P and N compared with the flow-weighted mean concentration (FWMC) from high-resolution bank-side analysers at each site. Results from the passive samplers were variable and largely underestimated the FWMC derived from the bank-side analysers. Laboratory tests using ambient river samples indicated good replication of advective throughflow using pumped water, although this appeared not to be a good analogue of river conditions where flow divergence was possible. Laboratory tests also showed good nutrient retention but not elution and these issues appeared to combine to limit the utility in ambient river systems at the small catchment scale.

Spatial distribution of arsenic and temporal variation of its concentration in rice

P>In order to gain insights into the transport and distribution of arsenic (As) in intact rice (Oryza sativa) plants and its unloading into the rice grain, we investigated the spatial distribution of As and the temporal variation of As concentration in whole rice plants at different growth stages. To the best of our knowledge, this is the first time that such a study has been performed.

Inductively coupled plasma mass spectroscopy (ICP-MS) and high-performance liquid chromatography (HPLC)-ICP-MS were used to analyze total As concentration and speciation. Moreover, synchrotron-based X-ray fluorescence (SXRF) was used to investigate in situ As distribution in the leaf, internode, node and grain.

Total As concentrations of vegetative tissues increased during the 2 wk after flowering. The concentration of dimethylarsinic acid (DMA) in the caryopsis decreased progressively with its development, whereas inorganic As concentration remained stable. The ratios of As content between neighboring leaves or between neighboring internodes were c. 0.6. SXRF revealed As accumulation in the center of the caryopsis during its early development and then in the ovular vascular trace.

These results indicate that there are different controls on the unloading of inorganic As and DMA; the latter accumulated mainly in the caryopsis before flowering, whereas inorganic As was mainly transported into the caryopsis during grain filling. Moreover, nodes appeared to serve as a check-point in As distribution in rice shoots.