bluuebunny/crossref_metadata_2025 huggingface dataset:
Multimodal liposomes for SPECT/MR imaging as a tool for in situ relaxivity measurements
Authors: de Vries Anke , Kok Maarten B. , Sanders Honorius M. H. F. , Nicolay Klaas , Strijkers Gustav J. , Grüll Holger
Published: February 2012

One of the major challenges of MR imaging is the quantification of local concentrations of contrast agents. Cellular uptake strongly influences different parameters such as the water exchange rate and the pool of water protons, and results in alteration of the contrast agent's relaxivity, therefore making it difficult to determine contrast agent concentrations based on the MR signal only. Here, we propose a multimodal radiolabeled paramagnetic liposomal contrast agent that allows simultaneous imaging with SPECT and MRI. As SPECT‐based quantification allows determination of the gadolinium concentration, the MRI signal can be deconvoluted to get an understanding of the cellular location of the contrast agent. The cell experiments indicated a reduction of the relaxivity from 2.7 ± 0.1 m m−1 s−1 to a net relaxivity of 1.7 ± 0.3 m m−1 s−1 upon cellular uptake for RGD targeted liposomes by means of the contrast agent concentration as determined by SPECT. This is not observed for nontargeted liposomes that serve as controls. We show that receptor targeted liposomes in comparison to nontargeted liposomes are taken up into cells faster and into subcellular structures of different sizes. We suggest that the presented multimodal contrast agent provides a functional readout of its response to the biological environment and is furthermore applicable in in vivo measurements. As this approach can be extended to several MRI‐based contrast mechanisms, we foresee a broader use of multimodal SPECT/MRI nanoparticles to serve as in vivo sensors in biological or medical research. Copyright © 2011 John Wiley & Sons, Ltd.
Improving T1 and T2 magnetic resonance imaging contrast agents through the conjugation of an esteramide dendrimer to high‐water‐coordination Gd(III) hydroxypyridinone complexes
Authors: Klemm Piper J. , Floyd William C. , Smiles Danil E. , Fréchet Jean M. J. , Raymond Kenneth N.
Published: February 2012

Commercial gadolinium magnetic resonance imaging (MRI) contrast agents are limited by low relaxivity (r1) and coordination to only a single water molecule (q = 1). Consequently, gram quantities of these agents must be injected to obtain sufficient diagnostic contrast. In this study, MRI contrast agents for T1 and T2 relaxivity were synthesized using hydroxypyridinone and terephthalamide chelators with mesityl and 1,4,7‐triazacyclononane capping moieties. When covalently conjugated to a highly biocompatible esteramide dendrimer, T2 relaxation rates up to 52 m m−1 s−1 and T1 relaxation rates up to 31 m m−1 s−1 per gadolinium were observed under clinically relevant conditions. These values are believed to be brought about by using a dendritic macromolecule to decrease the molecular tumbling time of the small molecule complexes. These agents also show high aqueous solubility and low toxicity in vitro. In this study we report six new compounds: three discrete complexes and three dendrimer conjugates. Copyright © 2012 John Wiley & Sons, Ltd.
Neuronal organization of the hemiellipsoid body of the land hermit crab, Coenobita clypeatus: Correspondence with the mushroom body ground pattern
Authors: Wolff Gabriella , Harzsch Steffen , Hansson Bill S. , Brown Sheena , Strausfeld Nicholas
Published: February 2012

Malacostracan crustaceans and dicondylic insects possess large second‐order olfactory neuropils called, respectively, hemiellipsoid bodies and mushroom bodies. Because these centers look very different in the two groups of arthropods, it has been debated whether these second‐order sensory neuropils are homologous or whether they have evolved independently. Here we describe the results of neuroanatomical observations and experiments that resolve the neuronal organization of the hemiellipsoid body in the terrestrial Caribbean hermit crab, Coenobita clypeatus, and compare this organization with the mushroom body of an insect, the cockroach Periplaneta americana. Comparisons of the morphology, ultrastructure, and immunoreactivity of the hemiellipsoid body of C. clypeatus and the mushroom body of the cockroach P. americana reveal in both a layered motif provided by rectilinear arrangements of extrinsic and intrinsic neurons as well as a microglomerular organization. Furthermore, antibodies raised against DC0, the major catalytic subunit of protein kinase A, specifically label both the crustacean hemiellipsoid bodies and insect mushroom bodies. In crustaceans lacking eyestalks, where the entire brain is contained within the head, this antibody selectively labels hemiellipsoid bodies, the superior part of which approximates a mushroom body's calyx in having large numbers of microglomeruli. We propose that these multiple correspondences indicate homology of the crustacean hemiellipsoid body and insect mushroom body and discuss the implications of this with respect to the phylogenetic history of arthropods. We conclude that crustaceans, insects, and other groups of arthropods share an ancestral neuronal ground pattern that is specific to their second‐order olfactory centers. J. Comp. Neurol. 520:2824–2846, 2012. © 2012 Wiley Periodicals, Inc.
Connections of the lateral hypothalamic area juxtadorsomedial region in the male rat
Authors: Hahn Joel D. , Swanson Larry W.
Published: February 2012

The connections of the lateral hypothalamic area juxtadorsomedial region (LHAjd) were investigated in a series of pathway‐tracing experiments involving iontophoretic co‐injection of the tracers Phaseolus vulgaris‐leucoagglutinin (PHA‐L; for outputs) and cholera toxin B subunit (CTB; for inputs). Results revealed that the LHAjd has connections with some 318 distinct gray matter regions encompassing all four subsystems—motor, sensory, cognitive, and behavioral state—included in a basic structure–function network model of the nervous system. Integration of these subsystems is necessary for the coordination and control of emotion and behavior, and in that regard the connections of the LHAjd indicate that it may have a prominent role. Furthermore, the LHAjd connections, together with the connections of other LHA differentiations studied similarly to date, indicate a distinct topographic organization that suggests each LHA differentiation has specifically differing degrees of involvement in the control of multiple behaviors. For the LHAjd, its involvement to a high degree in the control of defensive behavior, and to a lesser degree in the control of other behaviors, including ingestive and reproductive, is suggested. Moreover, the connections of the LHAjd suggest that its possible role in the control of these behaviors may be very broad in scope because they involve the somatic, neuroendocrine, and autonomic divisions of the nervous system. In addition, we suggest that connections between LHA differentiations may provide, at the level of the hypothalamus, a neuronal substrate for the coordinated control of multiple themes in the behavioral repertoire. J. Comp. Neurol. 520:1831–1890, 2012. © 2012 Wiley Periodicals, Inc.
Electron tomographic analysis of synaptic ultrastructure
Authors: Burette Alain C. , Lesperance Thomas , Crum John , Martone Maryann , Volkmann Niels , Ellisman Mark H. , Weinberg Richard J.
Published: February 2012

Synaptic function depends on interactions among sets of proteins that assemble into complex supramolecular machines. Molecular biology, electrophysiology, and live‐cell imaging studies have provided tantalizing glimpses into the inner workings of the synapse, but fundamental questions remain regarding the functional organization of these “nano‐machines.” Electron tomography reveals the internal structure of synapses in three dimensions with exceptional spatial resolution. Here we report results from an electron tomographic study of axospinous synapses in neocortex and hippocampus of the adult rat, based on aldehyde‐fixed material stabilized with tannic acid in lieu of postfixation with osmium tetroxide. Our results provide a new window into the structural basis of excitatory synaptic processing in the mammalian brain. J. Comp. Neurol. 520:2697–2711, 2012. © 2012 Wiley Periodicals, Inc.
Organizational motifs for ground squirrel cone bipolar cells
Authors: Light Adam C. , Zhu Yongling , Shi Jun , Saszik Shannon , Lindstrom Sarah , Davidson Laura , Li Xiaoyu , Chiodo Vince A. , Hauswirth William W. , Li Wei , DeVries Steven H.
Published: February 2012

In daylight vision, parallel processing starts at the cone synapse. Cone signals flow to On and Off bipolar cells, which are further divided into types according to morphology, immunocytochemistry, and function. The axons of the bipolar cell types stratify at different levels in the inner plexiform layer (IPL) and can interact with costratifying amacrine and ganglion cells. These interactions endow the ganglion cell types with unique functional properties. The wiring that underlies the interactions among bipolar, amacrine, and ganglion cells is poorly understood. It may be easier to elucidate this wiring if organizational rules can be established. We identify 13 types of cone bipolar cells in the ground squirrel, 11 of which contact contiguous cones, with the possible exception of short‐wavelength‐sensitive cones. Cells were identified by antibody labeling, tracer filling, and Golgi‐like filling following transduction with an adeno‐associated virus encoding for green fluorescent protein. The 11 bipolar cell types displayed two organizational patterns. In the first pattern, eight to 10 of the 11 types came in pairs with partially overlapping axonal stratification. Pairs shared morphological, immunocytochemical, and functional properties. The existence of similar pairs is a new motif that might have implications for how signals first diverge from a cone to bipolar cells and then reconverge onto a costratifying ganglion cell. The second pattern is a mirror symmetric organization about the middle of the IPL involving at least seven bipolar cell types. This anatomical symmetry may be associated with a functional symmetry in On and Off ganglion cell responses. J. Comp. Neurol. 520:2864–2887, 2012. © 2012 Wiley Periodicals Inc.
Corporate Social Responsibility Reporting in China: An Overview and Comparison with Major Trends
Authors: Noronha Carlos , Tou Si , Cynthia M. I. , Guan Jenny J.
Published: February 2012

Given the scant literature of corporate social responsibility (CSR) reporting on mainland China, especially in the Western academia, the present paper aims at providing an overview of the CSR reporting requirements in that country. A comparison with major reporting trends such as the adoption of GRI‐G3 is made to further understand the development of CSR in China. A literature review of prior studies is also conducted concerning CSR in China, especially those which are available only in the Chinese language. In summary, the overview indicates that CSR reporting in China is at a very preliminary stage and more empirical research in this area is urgently called for. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
OMIP‐006: Phenotypic subset analysis of human T regulatory cells via polychromatic flow cytometry
Authors: Murdoch David M. , Staats Janet S. , Weinhold Kent J.
Published: February 2012

This panel was optimized for the enumeration and phenotypic characterization of T regulatory cells (Tregs) within the CD4+ T‐cell pool using human peripheral blood mononuclear cells (PBMC) using intranuclear and intracellular staining methods. The panel was optimized for HIV+ clinical trial specimens through the use of HIV‐infected and normal donor PBMC. Because the panel is to be used in the context of testing cryopreserved PBMC obtained from multiple sites participating in clinical trials, it was essential to develop an assay that performed well using cryopreserved PBMC. Other tissue types have not been tested. © 2012 International Society for Advancement of Cytometry.
Diabetes and cancer: the mechanistic implications of epidemiological analyses from the Hong Kong Diabetes Registry
Authors: Yang Xilin , So Wing‐Yee , Ma Ronald CW , Kong Alice PS , Xu Gang , Chan Juliana CN
Published: February 2012

Diabetes is a disorder of energy metabolism associated with increased cancer risk, but the underlying mechanism is poorly understood. In a prospective cohort of patients enrolled in the Hong Kong Diabetes Registry, we explored risk factors for cancer including drug usage in type 2 diabetes. In a series of published papers, we reported a linear risk association of cancer with glycated haemoglobin with a threshold at 6.0%–6.5% and non‐linear risk associations of body mass index, low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, triglyceride and white blood cell (WBC) count in V‐shaped or A‐shaped manners. Detailed pharmacoepidemiological analysis revealed markedly attenuated cancer risk in patients treated with insulin and oral anti‐diabetic drugs compared with non‐users of these drugs. We further observed significant drug–subphenotype interactions with attenuated cancer risk in metformin users with low high‐density lipoprotein cholesterol, renin‐angiotensin system (RAS) inhibitor users with high WBC count and statin users with co‐presence of low low‐density lipoprotein cholesterol plus albuminuria or low triglyceride. These novel observations corroborate with experimental findings of possible consequences of hyperglycaemia on dysregulation of cholesterol metabolism, renin‐angiotensin system and adenosine 5′‐monophosphate‐activated protein kinase pathways, all of which may be implicated in carcinogenesis. On the basis of these epidemiological and experimental findings, we argue for the strong need to strengthen the health care system to ensure that type 2 diabetes subjects receive appropriate drugs to optimize internal milieu to reduce all events including cancer. Apart from mechanistic studies, large‐scale, randomized clinical trials using medications such as statin, renin‐angiotensin system inhibitors and metformin in patients with risk‐conferring subphenotypes are needed to confirm their anti‐cancer effects. Copyright © 2012 John Wiley & Sons, Ltd.
“Caging” Anions through Crystal Engineering to Avoid Polymerization: Structural, Conformational and Theoretical Investigations of New Halocadmate [Cd2X7]3– Anions (X = Cl/Br)
Authors: Sharma Raj P. , Singh Ajnesh , Venugopalan Paloth , Yanan Guo , Yu Jihong , Angeli Celestino , Ferretti Valeria
Published: February 2012

Two new discrete anionic species, [Cd2Cl7]3– and [Cd2Br7]3–, have been isolated in the form of cobalt(III) complex salts, [Co(phen)3][Cd2Cl7]·3H2O (1) and [Co(phen)3][Cd2Br7]·2H2O (2). The complex salts have been characterized by spectroscopic techniques and other investigations like TGA, solubility product measurements, conductance measurements, luminiscent study, DFT calculations and single crystal structure determinations. The new discrete [Cd2X7]3– anions reside in cavities that are formed by complex cations and are stabilized by different noncovalent interactions (hydrogen bonding, π–π stacking, C–H···π and anion···π). With the help of DFT calculations, an in depth investigation has been conducted into what happens to the conformation of these anions in crystal, solution and gas phase, and the nature of the Cd–halogen bond has been elucidated.
Physical Properties of Eu2+‐Containing Cryptates as Contrast Agents for Ultrahigh‐Field Magnetic Resonance Imaging
Authors: Garcia Joel , Kuda‐Wedagedara Akhila N. W. , Allen Matthew J.
Published: February 2012

The kinetic stabilities and relaxivities of a series of Eu2+‐containing cryptates have been investigated. Transmetallation studies, which monitored the change in the longitudinal relaxation rate of water protons in the presence of Ca2+, Mg2+, and Zn2+, demonstrated that the cryptate structure influenced the stability, and two of the cryptates studied were inert to transmetallation in the presence of these endogenous ions. The efficacy of these cryptates was determined at different magnetic field strengths, temperatures, and pH values. Cryptate relaxivity was found to be higher at ultrahigh field strengths (7 and 9.4 T) relative to clinically relevant field strengths (1.4 and 3 T), but the efficiency of these cryptates decreased as the temperature increased. In addition, a variation in pH did not yield significant changes in the efficacy of the cryptates. These studies establish a foundation of important properties that are necessary to develop effective positive contrast agents for magnetic resonance imaging from Eu2+‐containing cryptates.
Manganese(II) Complexes as Potential Contrast Agents for MRI
Authors: Drahoš Bohuslav , Lukeš Ivan , Tóth Éva
Published: February 2012

Mn2+ has five unpaired d electrons, a long electronic relaxation time, and labile water exchange, which make it an attractive alternative to Gd3+ in the design of contrast agents for medical Magnetic Resonance Imaging. In order to ensure in vivo safety and high contrast agent efficiency, the Mn2+ ion has to be chelated by a ligand that provides high thermodynamic stability and kinetic inertness of the complex and has to have at least one free coordination site for a water molecule. Unfortunately, these two requirements are contradictory, as lower denticity of the ligands, which leads to more inner‐sphere water molecules often implies a decreased stability of the complex, and, therefore, it is necessary to find a balance between both requirements. In the last decade, a large amount of experimental data has been collected to characterize the physico‐chemical properties of Mn2+ chelates with variable ligand structures. They now allow for establishing trends of how the ligand structure, the rigidity of the ligand scaffold, and its donor–acceptor properties influence the thermodynamic, kinetic, and redox stability of the Mn2+ complex. This microreview surveys the current literature in this field.
Jatropha oil and karanja oil as carbon sources for production of sophorolipids
Authors: Wadekar Sushant D. , Kale Sandeep B. , Lali Arvind M. , Bhowmick Dipti Narayan , Pratap Amit P.
Published: February 2012

Biosurfactants like sophorolipids (SL) are mild and environmentally friendly surfactants to be used in cosmetics and health care products. In addition to surfactant properties, SL also possess antimicrobial and skin healing properties. SL are produced by microbial fermentation using refined vegetable oils with glucose as a carbon source. This affects the economics of the production of SL. In the present work, non‐traditional oils like jatropha oil, karanja oil, and neem oil were used as newer feedstock for fermentative production of SL using Starmerella bombicola (ATCC 22214). In the fermentation, jatropha oil and karanja oil gave 6.0 and 7.6 g/L of SL (mainly lactonic form), respectively. HPLC, liquid chromatography–mass spectrometer, and 1H NMR of crude SL obtained from fermentation broth showed lactonic form of two major SL. Oleic acid and linoleic acid were preferentially consumed over other fatty acids by the organism. Neem oil gave lower yield, i.e., 2.63 g/L of SL (mainly acidic form).

Practical applications: Jatropha oil and karanja oil are one of the non‐traditional oils grown wildly in India that have large potential that is still to be explored. These oils contain non‐glycerides components that exclude their use as edible oil. These oils can be used as substrate for SL that can find novel applications like in soil remediation, skin care production, antimicrobial agents, low foaming detergents, and food additives. The current study has provided proof of concept work that has indicated the potential of these oils to be used as substrate for SL. It has opened new avenues and there is further scope to improve the yield by validating the process parameters like aeration rate, residual substrate recycle and pH control.
Development of a highly sensitive assay for enzyme-mediated reductive degradation of polychlorinated dibenzo-p-dioxin
Authors: Suzuki Yuzo , Nakamura Masaya , Otsuka Yuichiro , Suzuki Nao , Ohyama Keisuke , Kawakami Takeshi , Sato Kanna , Kajita Shinya , Hishiyama Shojiro , Takahashi Atsushi , Katayama Yoshihiro
Published: February 2012

The degradation of 2-chloro-4,5-O-(4′-methyl-7′, 8′-diphenyl)ether (CMDPE), an analog of 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD), mediated by Geobacillus sp. UZO 3 cell-free extract was monitored. Ethyl acetate extracts of a complete reaction mixture incubated at 65°C for 18 h were analyzed either by thin layer chromatography (TLC) fractionation coupled with spectrometric detection or by gas chromatography–mass spectrometry (GC-MS). The reaction product 4-methylumbelliferone (4MU) was successfully isolated by TLC and visualized by a transilluminator at 450 nm. The 4MU, 4-chlorophenol, and reaction intermediate 6-chlorophenoxy-4-methylumbelliferone were all successfully detected by GC-MS. The presence of these compounds suggest that Geobacillus sp. UZO 3 cell-free extract also catalyzes the reductive cleavage of the diaryl ether bonds of CMDPE in a similar mechanism previously reported in 2,7-DCDD. In the present study, the authors describe a simple and highly sensitive fluorescent assay for a new dioxin degrading enzyme(s). Environ. Toxicol. Chem. 2012; 31: 1072–1075. © 2012 SETAC
Exposure time–dependent effects on the relative potencies and additivity of PAHs in the Ah receptor-based H4IIE-luc bioassay
Authors: Larsson Maria , Orbe Dan , Engwall Magnus
Published: February 2012

In the present study, relative potency factors (REPs) of 16 individual polycyclic aromatic hydrocarbons (PAHs) were investigated using the H4IIE-luc bioassay. Exposure time-dependent effects on the REPs were examined using 24, 48, and 72 h of exposure. Seven different mixtures of PAHs were tested for additivity at an exposure time of 24 h. Three of the PAH mixtures were also studied at 48 and 72 h of exposure. The mixture toxicities were predicted using the REP concept and the concentration addition (CA) model. Relative potency factor values investigated in the present study were similar to those reported in earlier studies. Declining REPs with an increasing exposure time were shown for all PAHs, indicating that this bioassay approach could be developed to assess the persistency of aryl hydrocarbon receptor (AhR) agonistic PAHs and in the risk assessment of complex PAH mixtures. The results from the mixture studies indicated that additive interactions of PAHs are time dependent. Generally, 48- and 72-h exposures resulted in biological effects that were similar to the CA and REP model predictions, while these models tended to underestimate the effect, to some extent, in the 24-h exposure, at least for the mixtures containing two to four PAHs. Thus, it cannot be ruled out that in the 24-h exposures, the tested PAH mixtures had slight synergistic effects. Further research is needed to identify and test additional AhR activating PAHs and investigate whether the effects in the H4IIE-luc bioassay are additive for more complex samples containing both PAHs and other AhR-activating contaminants. Also, the observed superinduction of luciferase by PAH-mixes warrants studies of whether this also can occur for relevant AhR-mediated endpoints in vivo. Environ. Toxicol. Chem. 2012; 31: 1149–1157. © 2012 SETAC
New invasive alien plant species in the forest‐steppe and northern steppe subzones of European Russia: secondary range patterns, ecology and causes of fragmentary distribution
Authors: Sukhorukov (Suchorukow) Alexander P.
Published: February 2012

Recent floristic investigations in several provinces located in the northern steppe and forest‐steppe subzones of European Russia have examined the naturalisation and rapid spreading of 13 annual and perennial invasive herbs. They can be considered as (potentially) dangerous neophytes in different plant formations: Eriochloa villosa, Panicum dichotomiflorum, Eragrostis albensis, Rumex patientia, Amaranthus powellii, Papaver dubium, Erysimum repandum, Sophora alopecuroides, Galega orientalis, Chaerophyllum aureum, Centaurea majorovii, Senecio dubitabilis, Lactuca saligna. Only a decade ago, very few of the above listed species were present in Central Russia. Chaerophyllum aureum, the most successful invader forms monodominant populations, stands at forest margins and in meadows and is transforming the existing vegetation structure. Eragrostis albensis and Amaranthus powellii have been well‐established in dump sites, in contrast Galega orientalis and Rumex patientia prefer open grassland (meadows, etc.). The remaiming species occur along the railroad beds. The supposed fragmentary distribution pattern seems to be just a result of insufficient study of alien species and/or the absence of specialists in some provinces. Several species (e.g. Senecio dubitabilis, Centaurea majorovii) are recently invasive new for many parts of European Russia. The ecological attributes, respectively, the invasive status of the alien species, mentioned above, are compared between this investigation area and Central/Western Europe. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluation of Archaeological Sourcing Techniques: Reconsidering and Re‐Deriving Hughes’ Four‐Fold Assessment Scheme
Authors: Frahm Ellery
Published: February 2012

As new analytical techniques are brought to sourcing studies and researchers compile data into multi‐laboratory databases, systematic evaluation is essential. The importance of precision and accuracy is clear, but Shackley (2005) also calls for “archaeological accuracy.” Hughes (1998) offered a framework to consider precision and accuracy alongside the concepts of reliability and validity. These four concepts can serve as a foundation to evaluate archaeological sourcing data and procedures, but adoption of Hughes’ framework has been nearly nonexistent. Unfortunately, Hughes’ formulations of reliability and validity are somewhat at odds with their conventional definitions, hindering his framework. Furthermore, the concept of precision has become outdated in analytical circles, and superfluous terms (e.g., replicability) have emerged in the archaeological literature. Here I consider the basis of Hughes’ framework and how its four components, when applied consistently by the sourcing community, are best applied to evaluate analytical data and techniques for sourcing.
Surveying the Townscape of Roman Ammaia in Portugal: An Integrated Geoarchaeological Investigation of the Forum Area
Authors: Vermeulen Frank , Corsi Cristina , De Dapper Morgan
Published: February 2012

Geoarchaeological research, integrating traditional excavations, and ground truthing with intensive geophysical surveys, aerial photography, and GIS‐based data processing, has revealed the full intramural plan of the abandoned Roman city of Ammaia in central Portugal. Although this multidisciplinary effort also focussed on understanding the town/territory relationships and the system of resource exploitation, this paper presents the most important results from fieldwork in the central monumental area of the town, the Roman Forum. Here, excavations, geomorphological survey, and an array of geophysical methods illuminate the long history of the site, from the first settlement and monument‐building phases in early Imperial times, to the ongoing post‐abandonment processes. This paper discusses some of the benefits of compiling these complementary data sets and proposes the use of a wide array of approaches in order to achieve full understanding of the complex topography and evolution of a classical urban site. It further demonstrates the need for effective stratigraphical control and geomorphological analysis of crucial areas revealed by high‐quality geophysics.
Medieval Dark Earth in an Active Alluvial Setting from the Uffizi Gallery Complex in Florence, Italy
Authors: Nicosia Cristiano , Langohr Roger , Mees Florias , Arnoldus‐Huyzendveld Antonia , Bruttini Jacopo , Cantini Federico
Published: February 2012

Archaeological excavations at the Biblioteca Magliabechiana, which is part of the Uffizi gallery complex in Florence (Tuscany, central Italy), exposed Dark Earth deposits between alluvial sediments of the nearby Arno River. The term Dark Earth refers to thick, dark colored, and seemingly homogeneous deposits occurring in urban settings throughout Europe, broadly dated to the post‐Roman period. The stratigraphic sequence of the Biblioteca Magliabechiana was investigated by integrating geomorphological, chronological, and archaeological information with micromorphological and soil analytical data. This combination of approaches resulted in the identification of an early phase of Dark Earth formation (7th century A.D.) during which the area was characterized by the accumulation of manure or night soil in wet peri‐fluvial conditions. After a phase of abandonment, Dark Earth accretion resumed (10th to early 11th century A.D.), at this stage due primarily to the dumping of domestic waste. Subsequent progressive abandonment of the area was followed by the deposition of alluvium, probably during the major flood of November 4, 1177. The present study demonstrates that Dark Earth is the outcome of strong bioturbation and human reworking acting on anthropogenic deposits and possibly on alluvial sediments.
VOLUNTARY PRIVATE HEALTH INSURANCE AMONG THE OVER 50s IN EUROPE
Authors: Paccagnella Omar , Rebba Vincenzo , Weber Guglielmo
Published: February 2012

Using data from Survey of Health, Ageing and Retirement in Europe (SHARE), we investigate the determinants of voluntary private health insurance (VPHI) among the over 50s in 11 European countries and their effects on healthcare spending. First, we find that the main determinants of VPHI are different in each country, reflecting differences in the underlying healthcare systems, but in most countries, education levels and cognitive abilities have a strong positive effect on holding a VPHI policy. We also analyse the effect of holding a voluntary additional health insurance policy on out‐of‐pocket (OOP) healthcare spending. We adopt a simultaneous equations approach to control for self‐selection into VPHI policy holding and find that, only in the Netherlands, VPHI policyholders have lower OOP spending than the rest of the population, whereas in some countries (Italy, Spain, Denmark and Austria), they spend significantly more. This could be due to not only increased utilisation but also cost‐sharing measures adopted by the insurers to counter the effects of moral hazard and to keep adverse selection under control. Copyright © 2012 John Wiley & Sons, Ltd.
River–aquifer interactions in a semi‐arid environment stressed by groundwater abstraction
Authors: McCallum Andrew M. , Andersen Martin S. , Giambastiani Beatrice M. S. , Kelly Bryce F. J. , Ian Acworth R.
Published: February 2012

Rivers and aquifers are, in many cases, a connected resource and as such the interactions between them need to be understood and quantified for the resource to be managed appropriately. The objective of this paper is to advance the understanding of river–aquifer interactions processes in semi‐arid environments stressed by groundwater abstraction. This is performed using data from a specific catchment where records of precipitation, evapotranspiration, river flow, groundwater levels and groundwater abstraction are analysed using basic statistics, hydrograph analysis and a simple mathematical model to determine the processes causing the spatial and temporal changes in river–aquifer interactions. This combined approach provides a novel but simple methodology to analyse river–aquifer interactions, which can be applied to catchments worldwide.

The analysis revealed that the groundwater levels have declined (~ 3 m) since the onset of groundwater abstraction. The decline is predominantly due to the abstraction rather than climatic changes (r = 0.84 for the relationship between groundwater abstraction and groundwater levels; r = 0.92 for the relationship between decline in groundwater levels and magnitude of seasonal drawdown). It is then demonstrated that, since the onset of abstraction, the river has changed from being gaining to losing during low‐flow periods, defined as periods with flow less than 0.5, 1.0 or 1.5 GL/day (1 GL/day = 1 × 106 m3/day). If defined as < 1.0 GL/day, low‐flow periods constitute approximately 65% of the river flows; the periods where the river is losing at low‐flow conditions are thus significant. Importantly, there was a significant delay (> 10 years) between the onset of groundwater abstraction and the changeover from gaining to losing conditions. Finally, a relationship between the groundwater gradient towards the river and the river flow at low‐flow is demonstrated. The results have important implications for water management as well as water ecology and quality. Copyright © 2012 John Wiley & Sons, Ltd.
Spatial and temporal intensification of lateral hyporheic flux in narrowing intra‐meander zones
Authors: Han Bangshuai , Endreny Theodore A.
Published: February 2012

Meander bends in alluvial rivers morphologically evolve towards meander cut‐off with narrowing intra‐meander necks, and this should steepen hydraulic gradients and intensify intra‐meander hyporheic flux. This research used dye tracking and head loss measurements in a 1 : 500 planimetrically scaled laboratory river table to quantify the spatial and temporal intensification of intra‐meander flux rates at two evolution ages. The younger meander bend, M1, had a sinuosity of 2.3, a river neck width of 0.39 cm, and 0.6% river slope, and the older meander bend, M3, had a sinuosity of 5.2, a river neck width of 0.12 cm, and 0.5% river slope. Flux into and out of the meander bend was estimated along the normalized curvilinear distance s*, with the meander neck at s* = 0.1 and s* = 0.9, the meander centroid at s* = 0.37 and s* = 0.63, and the apex at s* = 0.5. Between the meander centroid and neck, we documented a 60% spatial intensification for M1 and a 90% spatial intensification for M3. Between M1 and M3, we documented a 135% temporal intensification at the neck and a 100% intensification at the centroid. Our empirical spatial and temporal intensification rates involving the M1 and the M3 scenario were one to three times lower than theoretical rates derived from a river evolution model with equivalent M1 and M3 planimetry. Overestimation by the theoretical model was attributed to exaggerated head loss caused by the model neglecting groundwater contributions to river stage. Hyporheic exchange provides critical ecosystem services, and its spatial and temporal variation with meander evolution should be considered in river management. Copyright © 2012 John Wiley & Sons, Ltd.
Assessing the effect of climate natural variability in water resources evaluation impacted by climate change
Authors: Liu Yanli , Zhang Jianyun , Wang Guoqing , Liu Jiufu , He Ruimin , Wang Hongjie , Liu Cuishan , Jin Junliang
Published: February 2012

Water resource assessment on climate change is crucial in water resource planning and management. This issue is becoming more urgent with climate change intensifying. In the current research of climate change impact, climate natural variability (fluctuation) has seldom been studied separately. Many studies keep attributing all changes (e.g. runoff) to climate change, which may lead to wrong understanding of climate change impact assessment. Because of lack of long enough historical series, impacts of climate variability have been always avoided deliberately. Based on Latin hypercube sampling technique, a block sampling approach was proposed for climate variability simulation in this study. The widely used time horizon (1961–1991) was defined as baseline period, and the runoff variation probability affected by climate natural variability was analysed. Allowing for seven future climate projections in total of three GCMs (CSIRO, NCAR, and MPI) and three emission scenarios (A1B, A2, and B1), the impact of future climate change on water resources was estimated in terms of separating the contribution from climate natural variability. Based on the analysis of baseline period, for the future period from 2021 to 2051, the impact of climate natural variability may play a major part, whereas for the period from 2061 to 2091, climate change attributed to greenhouse gases may dominate the changing process. The results show that changes from climate variability possess a comparable magnitude, which highlights the importance to separate impacts of climate variability in assessing climate change, instead of attributing all changes to climate change solely. Copyright © 2012 John Wiley & Sons, Ltd.
Simplification of biotic ligand models of Cu, Ni, and Zn by 1-, 2-, and 3-parameter transfer functions
Authors: Verschoor Anja J , Vink Jos PM , Vijver Martina G
Published: February 2012

Biotic ligand models for calculation of watertype-specific no effect concentrations are recognized as a major improvement in risk assessment of metals in surface waters. Model complexity and data requirement, however, hamper the regulatory implementation. To facilitate regulatory use, biotic ligand models (BLM) for the calculation of Ni, Cu, and Zn HC5 values were simplified to linear equations with an acceptable level of accuracy, requiring a maximum of 3 measured water chemistry parameters. In single-parameter models, dissolved organic carbon (DOC) is the only significant parameter with an accuracy of 72%–75% to predict HC5s computed by the full BLMs. In 2-parameter models, Mg, Ca, or pH are selected by stepwise multiple regression for Ni, Cu, and Zn HC5, respectively, and increase the accuracy to 87%–94%. The accuracy is further increased by addition of a third parameter to 88%–97%. Three-parameter models have DOC and pH in common, the third parameter is Mg, Ca, or Na for HC5 of Ni, Cu, and Zn, respectively. Mechanisms of chemical speciation and competitive binding to the biotic ligand explain the selection of these parameters. User-defined requirements, such as desired level of reliability and the availability of measured data, determine the selection of functions to predict HC5. Integr Environ Assess Manag 2012; 8: 738–748. © 2012 SETAC
Good modeling practice guidelines for applying multimedia models in chemical assessments
Authors: Buser Andreas M , MacLeod Matthew , Scheringer Martin , Mackay Don , Bonnell Mark , Russell Mark H , DePinto Joseph V , Hungerbühler Konrad
Published: February 2012

Multimedia mass balance models of chemical fate in the environment have been used for over 3 decades in a regulatory context to assist decision making. As these models become more comprehensive, reliable, and accepted, there is a need to recognize and adopt principles of Good Modeling Practice (GMP) to ensure that multimedia models are applied with transparency and adherence to accepted scientific principles. We propose and discuss 6 principles of GMP for applying existing multimedia models in a decision-making context, namely 1) specification of the goals of the model assessment, 2) specification of the model used, 3) specification of the input data, 4) specification of the output data, 5) conduct of a sensitivity and possibly also uncertainty analysis, and finally 6) specification of the limitations and limits of applicability of the analysis. These principles are justified and discussed with a view to enhancing the transparency and quality of model-based assessments. Integr Environ Assess Manag 2012; 8: 703–708. © 2012 SETAC
Quantum molecular mechanics—a noniterative procedure for the fast Ab Initio calculation of closed shell systems
Authors: Moura Gustavo L. C. , Simas Alfredo M.
Published: February 2012

In this article, we advance the foundations of a strategy to develop a molecular mechanics method based not on classical mechanics and force fields but entirely on quantum mechanics and localized electron‐pair orbitals, which we call quantum molecular mechanics (QMM). Accordingly, we introduce a new manner of calculating Hartree–Fock ab initio wavefunctions of closed shell systems based on variationally preoptimized nonorthogonal electron pair orbitals constructed by linear combinations of basis functions centered on the atoms. QMM is noniterative and requires only one extremely fast inversion of a single sparse matrix to arrive to the one‐particle density matrix, to the electron density, and consequently, to the ab initio electrostatic potential around the molecular system, or cluster of molecules. Although QMM neglects the smaller polarization effects due to intermolecular interactions, it fully takes into consideration polarization effects due to the much stronger intramolecular geometry distortions. For the case of methane, we show that QMM was able to reproduce satisfactorily the energetics and polarization effects of all distortions of the molecule along the nine normal modes of vibration, well beyond the harmonic region. We present the first practical applications of the QMM method by examining, in detail, the cases of clusters of helium atoms, hydrogen molecules, methane molecules, as well as one molecule of HeH+ surrounded by several methane molecules. We finally advance and discuss the potentialities of an exact formula to compute the QMM total energy, in which only two center integrals are involved, provided that the fully optimized electron‐pair orbitals are known. © 2012 Wiley Periodicals, Inc.
Design of chitosan/PSf self‐assembly membrane to mitigate fouling and enhance performance in trypsin separation
Authors: Hamzah Sofiah , Ali Nora'aini , Mohammad Abdul Wahab , Ariffin Marinah Mohd , Ali Asmadi
Published: February 2012

BACKGROUND: Membrane fouling in downstream processing has become a major obstacle in enzyme production. The use of a membrane with high surface hydrophilicity may be an acceptable way to overcome this problem. In this study, the effects of dip time on chitosan incorporation were investigated to produce a low fouling ultrafiltration membrane for trypsin separation.

RESULT: Pristine ultrafiltration membrane with a polymer concentration of 15% was developed via phase inversion. Membrane surface modification was performed using chitosan solution with different dip times. Membranes with a 60‐min dip time provided optimum trypsin transmission (about 91.8%). Such membranes have a high permeability coefficient (71 L m−2 h−1) and good porosity (about 89.6%). The hydrophilicity of this modified membrane was also improved by 50% compared with the native membrane, and its flux recovery was about 89.8%. The successful assembly of chitosan onto the membrane's surface was ascertained by ATR‐FTIR and X‐ray diffractometry (XRD). The morphology of this membrane was significantly different from that of native membrane.

CONCLUSION: The experimental results show that membrane dip time exerts a significant influence on the self‐assembly of chitosan particles onto the membrane's surface, and this process can be used to produce a potentially low‐fouling UF membrane for trypsin separation. Copyright © 2012 Society of Chemical Industry
Involvement of ryanodine receptors in tetanic sciatic stimulation‐induced long‐term potentiation of spinal dorsal horn and persistent pain in rats
Authors: Lü Ning , Cheng Long‐Zhen , Zhang Yu‐Qiu , Lü Bai‐Chang , Li Yun‐Qing , Zhao Zhi‐Qi
Published: February 2012

Tetanic stimulation of the sciatic nerve induces long‐term potentiation (LTP) of C‐fiber‐evoked field potentials in the spinal dorsal horn and persistent pain, suggesting that spinal LTP may be a substrate for central sensitization of the pain pathway. However, its cellular mechanism remains unclear. The present study provides electrophysiological and behavioral evidence for the involvement of ryanodine receptor (RyR) in the induction of spinal LTP and persistent pain in rats. The specific inhibitor of ryanodine receptor, ryanodine and dantrolene, dose dependently blocked the induction, but not maintenance, of spinal LTP and reduced persistent pain behaviors induced by tetanic sciatic stimulation. Both cyclic ADP ribose (cADPR), an endogenous agonist of RyR, and (±)‐1,4‐dihydro‐2,6‐dimethyl‐5‐nitro‐4‐[2‐(trifluromethyl)‐phenyl]‐3‐pyridine carboxylic acid methyl ester (Bay K 8644), an agonist of L‐type calcium channel, attenuated ryanodine‐induced inhibition. Immunohistochemistry and electron microscopic observation showed that RyR subtypes RyR1 and RyR3 were located in the spinal dorsal horn. The results suggest that RyRs are involved in synaptic plasticity of the spinal pain pathway and may be a novel target for treating pain. © 2012 Wiley Periodicals, Inc.
Influence of acid hydrolysis on thermal and rheological properties of amaranth starches varying in amylose content
Authors: Kong Xiangli , Kasapis Stefan , Bao Jinsong , Corke Harold
Published: February 2012

BACKGROUND: The granules of amaranth starch are very small compared with starches from other sources. In the current work, amaranth starches with different amylose contents were treated with hydrochloric acid as a function of time in order to study the effect of acid treatments on starches. Differential scanning calorimetry and dynamic oscillation in shear were employed to analyse the thermal and rheological properties of acid‐modified amaranth starch.

RESULTS: Results showed that gelatinisation temperatures and enthalpy change of gelatinisation (ΔH) decreased steeply initially, and had a slight increase with further treatment up to 12 h then decreased, an outcome that reflected distinct resistance to acid with various amylose contents. Rheological parameters of storage and loss moduli during heating, cooling and frequency sweep of modified starches reflected the differential scanning calorimetry results by decreasing in value as the time of acid hydrolysis increased.

CONCLUSION: With amylose content increase, the effects of acid hydrolysis on gelatinisation temperatures became less pronounced. Nevertheless, prolonged acid hydrolysis decreased the storage and loss moduli, with the starch pastes becoming more liquid‐like. Copyright © 2012 Society of Chemical Industry
Variability and relationship among Mixolab and Falling Number evaluation based on influence of fungal α‐amylase addition.
Authors: Codinǎ Georgiana Gabriela , Mironeasa Silvia , Mironeasa Costel
Published: February 2012

BACKGROUND: In bread‐making technology, α‐amylase activity is routinely measured with a Falling Number device to predict wheat flour quality. The aim of this study was to determine the possibility of using Mixolab parameters to assess the Falling Number (FN) index. The effects of different doses of fungal α‐amylase addition on the Mixolab characteristics and FN index values were investigated.

RESULTS: Principal component analysis was performed in order to illustrate the relationships between the Mixolab parameters and the FN index. To highlight the linear combination between the FN index values and the Mixolab parameters used to evaluate starch pasting properties (C3, C4, C5 and point differences C34 and C54), a multivariate prediction model was developed. Greatest precision (R = 0.728) was obtained for the linear regression FN = f(C4, C54) model. This model was tested on a different sample set than the one on which it was built. A high correlation was obtained between predictive model and measured FN index values (r = 0.896, P = 0.01).

CONCLUSION: The model provides a framework to predict the evolution of the FN index, which is predicted by the torque for cooking stability (C4) and the difference between points C5 and C4 (C54). The obtained results suggested that the Mixolab device could be a reliable instrument for evaluation of the FN index values. Copyright © 2012 Society of Chemical Industry
Enzymatic biodiesel production – the way of the future
Authors: Fan Xiaohu
Published: February 2012

Enzymatic biodiesel production shows a very high potential to be an eco‐friendly process compared with traditional chemical processes, which could pose downstream processing problems. As an environmentally benign green approach, enzymatically catalyzed biodiesel production avoids the generation of wastewater and eases the recovery of high purity glycerol. This article discusses the benefits of using enzymatic approach. Both the opportunities and challenges are covered.