bluuebunny/crossref_metadata_2025_split huggingface dataset:
ELISA analysis of β‐secretase cleavage of the Swedish amyloid precursor protein in the secretory and endocytic pathways
Authors: Steinhilb Michelle L. , Turner R. Scott , Gaut James R. 
Published: March 2003

AbstractLimiting beta amyloid (Aβ) production could become an important therapeutic target in Alzheimer's disease (AD). Aβ is derived by the sequential cleavage of amyloid precursor protein (APP) by β‐ and γ‐secretases. A double missense mutation in APP found in a Swedish pedigree (APPsw) elevates Aβ40 and Aβ42 production. Aβ production and, therefore, β‐secretase cleavage of APPsw reportedly occur in the endoplasmic reticulum (ER), Golgi and endocytic compartments. However, the relative contribution of β‐secretase cleavage occurring in each compartment has not been determined. Experiments described here use a novel ELISA to measure the β‐cleaved product, APPswβ. Using this ELISA, we provide new information regarding the relative amount of β‐secretase cleavage of APPsw that occurs in secretory and endocytic pathways. Using a dilysine retrieval motif to retain APPsw in the ER, we discovered that less than 15% of the β‐secretase cleavage was still detected. Experiments utilizing endocytosis‐impaired mutants of APPsw revealed that little or no β‐secretase cleavage of APPsw appears to take place through endocytosis. Surprisingly, deletion of the entire cytoplasmic tail increased both APPswβ and Aβ secretion, suggesting that protein interactions with this region normally impede β‐secretase cleavage. These results suggest that APPsw is cleaved by β‐secretase late in the secretory pathway.
Modulation of cannabinoid agonist binding by 5‐HT in the rat cerebellum
Authors: Devlin Mark G. , Christopoulos Arthur 
Published: March 2003

AbstractCross‐talk between cannabinoid CB1 and serotonin 5‐HT receptors in rat cerebellar membranes was investigated using radioligand binding. In competition against the CB1 antagonist, [3H]SR141716A, the agonist, WIN 55,212‐2 yielded a biphasic isotherm. The majority of binding was to a high‐affinity state that was significantly reduced by the GTP analogue, Gpp(NH)p. Interestingly, 5‐HT enhanced the high‐affinity binding constant of WIN 55,212‐2 while attenuating the proportion of high‐affinity binding. 5‐HT also significantly reduced the proportion of high‐affinity binding of the cannabinoid agonist, HU 210, but had no effect on the agonist, CP 55,940. The effect of 5‐HT on WIN 55,212‐2 binding was inhibited by the 5‐HT2 receptor antagonist ritanserin as well as Gpp(NH)p, suggesting a dependence on the 5‐HT2 receptor and on G protein‐receptor interactions, respectively. Subsequent [3H]WIN 55,212‐2 dissociation kinetic experiments revealed that 5‐HT promoted a slower‐dissociating species of radiolabelled agonist‐receptor complex. Our findings support a membrane‐delimited cross‐talk between two G protein‐coupled receptors that are co‐localized in certain cells of the central nervous system. Intriguingly, the cannabinoid agonist dependence of the 5‐HT modulatory effect suggests that agonist‐specific conformations of the CB1 receptor may also be important in determining the extent of this cross‐talk.
In situ13CO2 pulse‐labelling of upland grassland demonstrates a rapid pathway of carbon flux from arbuscular mycorrhizal mycelia to the soil
Authors: Johnson D. , Leake J. R. , Ostle N. , Ineson P. , Read D. J. 
Published: March 2003

Summary

The flux of pulse‐derived 13C from upland pasture plants to the external mycelium of their arbuscular mycorrhizal (AM) symbionts was traced and quantified over a 7‐d post‐labelling period.
Mesh cores, which allowed in‐growth of native AM mycelium but were impenetrable to roots, were inserted into unlimed and limed plots and the surrounding vegetation was exposed to 13CO2 at ambient CO2 concentrations.
Release of 13CO2 from cores colonized by AM mycelium peaked 9–14 h after labelling and declined within 24 h after severance of mycelial connections to roots. Between 5 and 8% of carbon lost by plants was respired by AM mycelium over the first 21 h after labelling. Liming increased the amount of carbon fixed by plants and subsequently allocated to fine roots and AM mycelium.
The results demonstrate for the first time under field conditions that AM mycelia provide a rapid and important pathway of carbon flux from plants to the soil and atmosphere.
A Propeller Thrust and Torque Dynamometer for Wind Tunnel Models
Authors: Molland A. F. , Turnock S. R. 
Published: March 2003

AbstractThe design, construction and calibration of a propeller thrust and torque dynamometer is described. The dynamometer was constructed primarily for the testing of model ship propellers when working upstream of a rudder. An outline of the specialised design requirements is given. The basic design concepts are described together with the reasons for the choice of flexures and their dimensions, strain gauges, circuits, bridge voltages and instrumentation. A brief description of the calibration process is given and the calibration results are described and discussed. It was found that there were no interactions between the components, a satisfactory overall measuring accuracy was achieved and the dynamometer had performed well in service. It is concluded that the overall design approach, concept and design details were satisfactory and suitable for this particular application.
Halogen contents of eclogite facies fluid inclusions and minerals: Caledonides, western Norway
Authors: Svensen H. , Jamtveit B. , Banks D. A. , Austrheim H. 
Published: March 2003

AbstractPrimary multiphase brine fluid inclusions in omphacite and garnet from low‐ to medium‐temperature eclogites have been analysed for Cl, Br, I, F, Li and SO4. Halogen contents and ratios provide information about trapped lower crustal fluids, even though the major element (Na, K, Ca) contents of inclusion fluids have been modified by fluid–mineral interactions and (step‐) daughter‐crystal formation after trapping. Halogens in the inclusion fluids were analysed with crush–leach techniques. Cl/Br and Cl/I mass ratios of eclogite fluids are in the range 31–395 and 5000–33 000, respectively. Most fluids have a Cl/Br ratio lower than modern seawater and a Cl/I ratio one order of magnitude lower than modern seawater. Fluids with the lowest Cl/Br and highest Cl/I ratios come from an eclogite that formed by hydration of granulite facies rocks, and may indicate that Br and I are fractionated into hydrous minerals. Reconstructions indicate that the inclusion fluids originally contained 500–4000 ppm Br, 1–14 ppm I and 33–438 ppm Li. Electron microprobe analyses of eclogite facies amphibole, biotite, phengite and apatite indicate that F and Cl fractionate most strongly between phengite (F/Cl mass ratio of 1469 ± 1048) and fluid (F/Cl mass ratio of 0.008), and the least between amphibole and fluid. The chemical evolution of Cl and Br in pore fluids during hydration reactions is in many ways analogous to Cl and Br in seawater during evaporation: the Cl/Br ratio remains constant until the aH2O value is sufficiently lowered for Cl to be removed from solution by incorporation into hydrous minerals.
Heterogeneous growth of cordierite in low P/T Tsukuba metamorphic rocks from central Japan
Authors: Miyazaki K. 
Published: March 2003

AbstractThis paper examines the spatial statistics of matrix minerals and complex patterned cordierite porphyroblasts in the low‐pressure, high‐temperature (low P/T) Tsukuba metamorphic rocks from central Japan, using a density correlation function. The cordierite‐producing reaction is sillimanite + biotite + quartz = K‐feldspar + cordierite + water. The density correlation function shows that quartz is distributed randomly. However, the density correlation functions of biotite, plagioclase and K‐feldspar show that their spatial distributions are clearly affected by the formation of cordierite porphyroblasts. These observations suggest that cordierite growth occurred through a selective growth mechanism: quartz adjacent to cordierite has a tendency to prevent the growth of cordierite, whereas other matrix minerals adjacent to cordierite have a tendency to enhance the growth of cordierite. The density correlation functions of complex patterned cordierite porphyroblasts show power‐law behaviour. A selective growth mechanism alone cannot explain the origin of the power‐law behaviour. Comparison of the morphology and fractal dimension of cordierite with two‐dimensional sections from a three‐dimensional diffusion‐limited aggregation (DLA) suggests that the formation of cordierite porphyroblasts can be modelled as a DLA process. DLA is the simple statistical model for the universal fractal pattern developed in a macroscopic diffusion field. Diffusion‐controlled growth interacting with a random field is essential to the formation of a DLA‐like pattern. The selective growth mechanism will provide a random noise for the growth of cordierite due to random distribution of quartz. Therefore, a selective growth mechanism coupled with diffusion‐controlled growth is proposed to explain the power‐law behaviour of the density correlation function of complex patterned cordierite. The results in this paper suggest that not only the growth kinetics but also the spatial distribution of matrix minerals affect the progress of the metamorphic reaction and pattern formation of metamorphic rocks.
Calculation of partial melting equilibria in the system Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O (NCKFMASH)
Authors: White R. W. , Powell R. , Holland T. J. B. 
Published: March 2003

AbstractA thermodynamic model for haplogranitic melts in the system Na2O–CaO–K2O–Al2O3–SiO2–H2O (NCKASH) is extended by the addition of FeO and MgO, with the data for the additional end‐members of the liquid incorporated in the
Holland & Powell (1998) internally consistent thermodynamic dataset. The resulting dataset, with the software

thermocalc, is then used to calculate melting relationships for metapelitic rock compositions. The main forms for this are P–T and T–X pseudosections calculated for particular rock compositions and composition ranges. The relationships in these full‐system pseudosections are controlled by the low‐variance equilibria in subsystems of NCKFMASH. In particular, the solidus relationships are controlled by the solidus relationships in NKASH, and the ferromagnesian mineral relationships are controlled by those in KFMASH. However, calculations in NCKFMASH allow the relationships between the common metapelitic minerals and silicate melt to be determined. In particular, the production of silicate melt and melt loss from such rocks allow observations to be made about the processes involved in producing granulite facies rocks, particularly relating to open‐system behaviour of rocks under high‐grade conditions.
Diffusion control of garnet growth, Harpswell Neck, Maine, USA
Authors: Spear F. S. , Daniel C. G. 
Published: March 2003

AbstractA detailed analysis of chemical zoning in two garnet crystals from Harpswell Neck, Maine, forms the basis of an interpretation of garnet nucleation and growth mechanisms. Garnet apparently nucleates initially on crenulations of mica and chlorite and quickly overgrows the entire crenulation, giving rise to complex two‐dimensional zoning patterns depending on the orientation of the thin section cut. Contours of Ca zoning cross those of Mn, Fe and Mg, indicating a lack of equilibrium among these major garnet constituents. Zoning of Fe, Mg and Mn is interpreted to reflect equilibrium with the rock matrix, whereas Ca zoning is interpreted to be controlled by diffusive transport between the matrix and the growing crystal.Image analysis reveals that the growth of garnet is more rapid along triple‐grain intersections than along double‐grain boundaries. Moreover, different minerals are replaced by garnet at different rates. The relative rate of replacement by garnet along double‐grain boundaries is ordered as muscovite > chlorite > plagioclase > quartz. Flux calculations reveal that replacement is limited by diffusion of Si along double‐grain boundaries to or from the local reaction site. It is concluded that multiple diffusive pathways control the bulk replacement of the rock matrix by garnet, with Si and Al transport being rate limiting in these samples.
Melt segregation in the continental crust: distribution and movement of melt in anatectic rocks
Authors: Sawyer E. W. 
Published: March 2003

AbstractThe grain‐ and outcrop‐scale distribution of melt has been mapped in anatectic rocks from regional and contact metamorphic environments and used to infer melt movement paths. At the grain scale, anatectic melt is pervasively distributed in the grain boundaries and in small pools; consequently, most melt is located parallel to the principal fabric in the rock, typically a foliation. Short, branched arrays of linked, melt‐bearing grain boundaries connect melt‐depleted parts of the matrix to diffuse zones of melt accumulation (protoleucosomes), where magmatic flow and alignment of euhedral crystals grown from the melt developed.The distribution of melt (leucosome) and residual rocks (normally melanocratic) in outcrop provides different, but complementary, information. The residual rocks show where the melt came from, and the leucosomes preserve some of the channels through which the melt moved, or sites where it pooled. Different stages of the melt segregation process are recorded in the leucosome–melanosome arrays. Regions where melting and segregation had just begun when crystallization occurred are characterized by short arrays of thin, branching leucosomes with little melanosome. A more advanced stage of melting and segregation is marked by the development of residual rocks around extensive, branched leucosome arrays, generally oriented along the foliation or melting layer. Places where melting had stopped, or slowed down, before crystallization began are marked by a high ratio of melanosome to leucosome; because most of the melt has drained away, very few leucosomes remain to mark the melt escape path — this is common in melt‐depleted granulite terranes. Many migmatites contain abundant leucosomes oriented parallel to the foliation; mostly, these represent places where foliation planes dilated and melt drained from the matrix via the branched grain boundary and larger branched melt channel (leucosome) arrays collected. Melt collected in the foliation planes was partially, or fully, expelled later, when discordant leucosomes formed. Leucosomes (or veins) oriented at high angles to the foliation/layering formed last and commonly lack melanocratic borders; hence they were not involved in draining the matrix of the melting layer. Discordant leucosomes represent the channels through which melt flowed out of the melting layer.
Metastability of granulites and processes of eclogitisation in the UHP region of western Norway
Authors: Wain A. L. , Waters D. J. , Austrheim H. 
Published: March 2003

AbstractThe Flatraket Complex, a granulite facies low strain enclave within the Western Gneiss Region, provides an excellent example of metastability of plagioclase‐bearing assemblages under eclogite facies conditions. Coesite eclogites are found <200 m structurally above and <1 km below the Flatraket Complex, and are separated from it by amphibolite facies gneisses related to pervasive late‐orogenic deformation and overprinting. Granulites within the Flatraket Complex equilibrated at 9–11 kbar, 700–800°C. These predate eclogite facies metamorphism and were preserved metastably in dry undeformed zones under eclogite facies conditions. Approximately 5% of the complex was transformed to eclogite in zones of fluid infiltration and deformation, which were focused along lithological contacts in the margin of the complex. Eclogitisation proceeded by domainal re‐equilibration and disequilibrium breakdown of plagioclase by predominantly hydration reactions. Both hydration and anhydrous plagioclase breakdown reactions were kinetically linked to input of fluid. More pervasive hydration of the complex occurred during exhumation, with fluid infiltration linked to dehydration of external gneisses. Eclogite facies shear zones within the complex equilibrated at 20–23 kbar, 650–800°C, consistent with the lack of coesite and with the equilibration conditions of external HP eclogites. If the complex experienced pressures equivalent to those of nearby coesite eclogites (> 28 kbar), unprecedented metastability of plagioclase and quartz is implied. Alternatively, a tectonic break exists between the Flatraket Complex and UHP eclogites, supporting the concept of a tectonic boundary to the UHP zone of the Western Gneiss Region. The distribution of eclogite and amphibolite facies metamorphic overprints demonstrates that the reactivity of the crust during deep burial and exhumation is strongly controlled by fluid availability, and is a function of the protolith.
Petrology, geochronology, and tectonics of shear zones in the Zermatt–Saas and Combin zones of the Western Alps
Authors: Cartwright I. , Barnicoat A. C. 
Published: March 2003

AbstractMetre to tens‐of‐metre wide, steeply dipping, greenschist facies shear zones that cut blueschists and eclogites of the Combin and Zermatt–Saas Zones at Täschalp and in adjacent areas of the western Alps were sites of extensive recrystallization driven by fluid flow and deformation. Rb–Sr data imply that these shear zones formed at 42–37 Ma with a systematic younging of structures northward toward, and into, the hangingwall of the Mischabel Structure. Shearing commenced at 400–475 °C and 400–500 MPa and continued as pressures and temperatures fell to 300–350 °C and 300–350 MPa. Individual shear zones were active for 2–3 Myr with later lower grade stages of shearing concentrated into narrow zones. Fluids that infiltrated the shear zones were water rich (XH2O > 0.9). Alteration zones around albite veins and at the margins of serpentinite bodies are penecontemporaneous with these shear zones and formed at approximately the same conditions. The eclogites were exhumed from c. 64 km at 44 Ma to 14–16 km at 42–41 Ma implying exhumation rates of 2–5 cm yr−1. Rapid exhumation was probably achieved by extension aided by buoyancy, following subduction of continental crust, and rapid erosion. The shear zones form part of a regional‐scale extensional system responsible for a significant portion of the exhumation of the subducted oceanic crust.
Determining the impact of health library services on patient care: a review of the literature
Authors: O’Connor Patrick 
Published: March 2003

AbstractThe impact of health library information has been studied in a number of settings and populations. This review examines both the methods employed and the outcomes reported in a series of impact studies conducted in four countries since the late 1980’s. It demonstrates that health library information can affect patient care outcomes in various ways and has high cognitive and clinical value in diagnosing and treating patients. But there remains no agreed technique or methodology for determining the level of this impact. In many cases evaluation of the health library’s impact will be located within a central process of evaluation of the greater organization to which the library belongs. Consequently, local ad hoc evaluation is rarely reported outside an organization. The author considers the question of whether it is worthwhile doing an impact study and what form it might take. The author concludes by identifying seminal papers on the topic.
Skin ageing: changes of physical properties of human skin in vivo
Authors: Diridollou S. , Vabre V. , Berson M. , Vaillant L. , Black D. , Lagarde J. M. , Grégoire J. M. , Gall Y. , Patat F. 
Published: March 2003

SynopsisWe have investigated in vivo the change with age of various parameters that describe the physical properties of skin. The parameters were derived from pressure/displacement curves obtained by applying reduced pressure to a small area of skin and measuring the resulting displacement by 20 MHz scan echography. By fitting the pressure/displacement curves to a theoretical model, the following skin parameters were obtained: E, Young's modulus or stiffness (in Pascals); σ0, the initial stress (in Pascals); and the unrestored energy ratio (UER), an index related to cutaneous non‐elasticity. These parameters, which are used in mechanics to define the intrinsic physical characteristics of materials, were measured for the first time on volar forearm skin of 206 male and female subjects, aged between 6 months and 90 years.The results showed that skin thickness increases until maturity and decreases for women over 50–60 years old, Young's modulus E increases linearly with age, and ageing is divided into two phases for natural stress, σ0 and the non‐elasticity index UER. Natural stress σ0 increases until maturity and then rapidly decreases. The non‐elasticity index decreases until puberty and steadily increases after puberty.This new procedure provides a simple quantitative assessment of the physical properties of the skin, revealing that the skin becomes thinner, stiffer, less tense and elastic with ageing.
Adapalene in the treatment of African patients
Authors: Jacyk WK 
Published: March 2003

ABSTRACTAim To assess the efficacy and safety of topical adapalene gel 0.1% as a treatment for acne vulgaris in black South African patients.Background African and other darker skin types represent a particular clinical challenge for dermatologists treating acne. In many cases, this is due to the higher risk of postinflammatory hyperpigmentation in patients with dark skin. Acne vulgaris is an extremely common dermatological problem among Africans and people of African descent worldwide. Few studies of any of the major acne therapies have been carried out in exclusively black populations, and relatively little is known about the specific responsiveness of black skin to these agents. The ideal acne treatment for black people would specifically target the inflammatory process, which so often results in hyperpigmentation. Topical retinoids do this to some degree, but they can be highly irritating and this in itself can provoke post‐treatment hyperpigmentation.Methods An open‐label study of adapalene 0.1% gel in 65 black South Africans, aged 12–30, for 12 weeks. Patients all had mild to moderate facial acne as defined by the Leeds scoring system; they were instructed to apply the medication once daily. Lesion counts and severity scores were assessed at 4, 8 and 12 weeks.Results A total of 44 subjects completed the trial and all three follow‐up visits. Adapalene gel 0.1% showed clear efficacy against both inflammatory and non‐inflammatory lesions. The drop in mean total facial‐lesion count ranged from 46 to 72% between the first and last visit, and in most cases, there was clear improvement in cosmesis. In two‐thirds of cases, patients experienced reductions in both number of hyperpigmented macules and density of hyperpigmentation.Conclusion Adapalene gel 0.1% is an effective, well‐tolerated topical therapy for black patients. It is able to reduce both inflammatory and non‐inflammatory lesions, as well as prevent and alleviate acne‐associated hyperpigmentation.