bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Adrenocorticotropin Receptor Mutation Alters Its Structure and Function, Causing Familial Glucocorticoid Deficiency
Authors: Artigas Rocío A. , Gonzalez Angel , Riquelme Erick , Carvajal Cristian A. , Cattani Andreína , Martínez-Aguayo Alejandro , Kalergis Alexis M. , Pérez-Acle Tomas , Fardella Carlos E. 
Published: May 2008

AbstractContext: Familial glucocorticoid deficiency (FGD) is an autosomal recessive disorder characterized by unresponsiveness to ACTH. In this study, two mutations of the ACTH receptor (MC2R) gene are reported in this FGD clinical case.Objective: The objective of the study was to characterize a novel MC2R gene mutation in a compound heterozygous patient with FGD phenotype.Design: This was a clinical case description, biochemical, molecular, and bioinformatics analysis to describe a novel MC2R gene mutation.Patients: The subject of the study was a male diagnosed with primary adrenal insufficiency. The family history showed nonconsanguineous healthy parents, three healthy siblings, and one brother affected with FGD.Main Outcome Measures: The mutant MC2R-Ala126Ser showed significantly lower activity when it was stimulated with ACTH-(1–24) than did cells transfected with wild-type MC2R.Results: The molecular studies demonstrated the presence of an adenine heterozygous insertion (InsA1347) in the MC2R gene (G217fs) in the patient. This insertion was due to a frame shift mutation in one allele and a premature stop codon codifying an aberrant receptor of 247 residues (27.2 kDa). We also found a novel heterozygous mutation alanine 126 by serine. Molecular dynamic simulations showed that serine 126 side chain fluctuates forming a noncanonical intrahelical hydrogen bond in the transmembrane helix 3 of the mutated receptor. This produces a structural rearrangement of the MC2R internal cavities that may affect the ligand recognition and signal transduction throughout the G protein.Conclusions: We propose a molecular explanation for the reduced activity exhibited by the MC2R alanine 126 by serine mutant.
Highly Prevalent Genetic Alterations in Receptor Tyrosine Kinases and Phosphatidylinositol 3-Kinase/Akt and Mitogen-Activated Protein Kinase Pathways in Anaplastic and Follicular Thyroid Cancers
Authors: Liu Zhi , Hou Peng , Ji Meiju , Guan Haixia , Studeman Kimberly , Jensen Kirk , Vasko Vasily , El-Naggar Adel K. , Xing Mingzhao 
Published: May 2008

Abstract
Context: Genetic alterations in receptor tyrosine kinases (RTKs) and phosphatidylinositol 3-kinase (PI3K)/Akt and MAPK pathways have not been fully defined in anaplastic and follicular thyroid cancers [anaplastic thyroid cancer (ATC), follicular thyroid cancer (FTC)].
Objective: The objective of the study was to explore a wide-range genetic basis for the involvement of these pathways in ATC.
Design: We examined mutations and copy number gains of a large panel of genes in these pathways and corresponding phosphorylation of ERK (p-ERK) and Akt.
Results: We found frequent copy gains of RTK genes, including EGFR, PDGFRα and -β, VEGFR1 and 2, KIT, and MET and in PIK3Ca, PIK3Cb, and PDK1 genes in the PI3K/Akt pathway. Mutations of Ras, PIK3Ca, PTEN, and BRAF genes and RET/PTC rearrangements were common, whereas mutations in PDK1, Akt1, Akt2, and RTK genes were uncommon in ATC. Overall, 46 of 48 ATC (95.8%) harbored at least one genetic alteration, and coexistence of two or more was seen in 37 of 48 ATC (77.1%). These genetic alterations were somewhat less common in FTC. Genetic alterations that could activate both the PI3K/Akt and MAPK pathways were found in 39 of 48 ATC (81.3%). RTK gene copy gains were preferentially associated with p-Akt, suggesting their dominant role in activating the PI3K/Akt pathway. The phosphorylation of Akt was far more common than p-ERK in FTC, and both were relatively common and often coexisted in ATC.
Conclusions: Genetic alterations in the RTKs and PI3K/Akt and MAPK pathways are extremely prevalent in ATC and FTC, providing a strong genetic basis for an extensive role of these signaling pathways and the development of therapies targeting these pathways for ATC and FTC, particularly the former.
Clay mineralogy across the P-T boundary of the Xiakou section, China: Evidence of clay provenance and environment
Authors: Hong Hanlie , Zhang Ning , Zhaohui Li , Xue Huijuang , Xia Wenchen , Yu Na 
Published: May 2008

AbstractThe provenance of clays in shaley intervals across the Permian-Triassic boundary (PTB) in the Xiakou section was investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM), and the results suggest that the layers have three different provenances. The layer P267-b has a loose texture with an oriented arrangement of detrital clay particles, consisting mainly of illite and minor chlorite with irregular outlines or ragged edges. The dehydroxylation reaction of the clays in this layer is characterized by an intense overlapping endothermic effect at ∼600°C, produced by mixed-layer illite-smectite (I-S) consisting of a mixture of cis-vacant (cv)and trans-vacant (tv) octahedral sheets derived from weathering of detrital illite. Layer P259-b shows a more condensed texture with a dark color, and is composed mainly of I-S and minor illite and chlorite. Evidence for alteration of detrital materials to clay mineral aggregates was observed under SEM. Similar to layer P267-b, an intense dehydroxylation reaction occurs at ∼600°C, indicating clays consisting of a mixture of tv and cv sheets and, therefore, that the sediments were derived from a mixture of terrigenous and volcanic sources, combining the texture and the clay-mineral composition of those sediments. However, the undisturbed lamination and relatively small grain size in this bed indicate a low-energy depositional environment. The clay-mineral compositions of the other layers are mainly of I-S with minor amounts of illite and chlorite. Their endothermic dehydroxylation reaction, however, occurs mainly at ∼660°C, indicating that cv sheets are dominant in the clays, and thus, are derived from smectites of volcanic origin. Observations by SEM show that clay minerals grow at the expense of detrital materials, confirming the diagenetic alteration of volcanic ashes in marine sediments. Illite and chlorite are the detrital clay minerals in the clay layers across the PTB in the Xiakou section. The presence of detrital illite and chlorite in the sediments means that an arid climate prevailed in the region during the end-Permian and early Triassic period.
Natrolitite, an unusual rock — Occurrence and petrographic and geochemical characteristics (Eastern Turkey)
Authors: Çiftçi Emin , Hogan John P. , Kolayli Hasan , Çadirli Emin 
Published: May 2008

AbstractVery unusual rocks consisting of natrolite (>95 vol.%) ± pargasite (<5 vol.%) and rarealbite (<1 vol. %) have been discovered in the Kop mountain range, eastern Turkey. We propose to call these rocks ‘natrolitite’ and ‘pargasite natrolitite’. They were produced by Na Si metasomatism of dikes and stocks of diorite through replacement of the intermediate primary igneous plagioclase to produce natrolite. The metasomatic alteration produced concentric elliptical zones characterized by distinct mineral assemblages centered on intrusions of diorite. The Central Zone 1 consists of variably albitized diorite with preserved magmatic textures (albite ± andesine ± pargasite ± quartz). Transition Zone 2 comprises natrolite-bearing diorite (natrolite ± albite ± andesine ± pargasite ± calcite ± quartz). Marginal Zone 3 is a rock made up almost entirely of natrolite (natrolite ± pargasite ± albite ± calcite ± chlorite). Outer Zone 4 occurs along the boundary between the natrolitite and the surrounding serpentinite and consists of listvenite, a rock which comprises magnesite, quartz, calcite, mica, talc, and hematite, indicating a role for CO2 in the metasomatic reactions, consistent with the presence of calcite in the alteration zones. Zone 5 consists essentially of brecciated serpentinite with numerous hydrothermal quartz veins and calcite veins. Whole-rock compositions document an increase in Na2O, Al2O3, and H2O from the core (central zone) to themargin while CaO, MgO, and SiO2 decrease. Plagioclase abundance and composition also varies outwards from the central core rocks where it occurs as a primary magmatic phase (∼95 vol.% An41−38) to the alteration zones (<5 vol.% An32−37) due to partial to complete replacement of plagioclase by natrolite with or without rare albite. The natrolites exhibit little variation in Si/Al ratios, ranging between 1.45 and 1.61, and are similar in composition to those reported in the literature. Accompanying pargasitic amphibole also becomes progressively more sodic in composition from the core rocks to the marginal zone rocks. Our analysis indicates that albitization preceded the formation of natrolite and that the formation of natrolite, instead of other more typical alteration minerals (e.g. analcime and paragonite), reflects Na metasomatism at lower chemical potentials for Al2O3 and SiO2. Potential sources of Na could be hypersaline brines or leaching of country rocks, such as trondhjemites. The fluids were driven in hydrothermal convection cells set up by theintrusion of thediorites.
Interaction of aqueous acidic-fluoride waste with natural tunisian soil
Authors: Hamdi Noureddine , Srasra Ezzedine 
Published: May 2008

AbstractClayey soils are essential materials used to reduce hydraulic conductivity and pollutant migration, common at sites of waste disposal. This study investigates the possible use of a Tunisian soil as a lining material for disposal sites for acidic-fluoride wastes. A permeability test on a waste-solution sample (pH = 2.7) obtained from a disposal site in southern Tunisia was conducted over a period of about 2 years. The test results show that the permeability decreased with time until stabilized at 8.33 × 10−11 m/s. After the permeability test, the samples retrieved from the permeameter show a degradation state which varied with the thickness of the specimen. These samples can be classified into three zones (Z1: unaffected, Z2: moderately affected; and Z3: extensively affected). Physicochemical characterization of the three samples (Z1, Z2, and Z3), and of the original argillaceous soil, was by X-ray diffraction, Fourier transform infrared spectroscopy, differential thermal and thermal gravimetric analysis, 29Si and 27Al nuclear magnetic resonance, and N2-adsorption techniques. The original sample consists essentially of palygorskite, kaolinite, and quartz. Sample Z3 underwent complete dissolution of kaolinite which supports the precipitation of fluoroaluminate and the appearance of an X-ray amorphous silica phase. In samples Z1 and Z2, the soil adsorbs fluoride at a rate of ∼68.5 mg/g and is highly resistant to acidic attack.
Quantitative phase analysis of bentonites by the rietveld method
Authors: Ufer K. , Stanjek H. , Roth G. , Dohrmann R. , Kleeberg R. , Kaufhold S. 
Published: May 2008

AbstractThirty six bentonite samples from 16 different locations were examined in order to demonstrate the applicability of a new Rietveld description approach for quantitative phase analysis. X-ray diffraction patterns of the bulk material were obtained and analyzed by the Rietveld method. The samples contain up to ten different minerals, with dioctahedral smectite as the major component. A model for turbostratic disorder of smectites was formulated inside a structure-description file of the Rietveld program BGMN. The quality of the refinements was checked using an internal standard mineral (10.0 or 20.0 wt.% corundum) and by cross-checking results with X-ray fluorescence (XRF) data. The corundum content was reproduced with only small deviations from the nominal values. A comparison of the chemical composition obtained by XRF and the composition as re-calculated from quantitative Rietveld results shows a satisfactory agreement, although X-ray amorphous components such as volcanic glasses were not considered. As a result of this study, the Rietveld method combined with the new structure model for turbostratic disorder has proven to be a suitable method for routine quantitative analysis of bentonites with smectites as the dominant clay minerals.
Inner ideals and intrinsic subspaces of linear pair geometries
Authors: Bertram Wolfgang , Löwe Harald 
Published: May 2008

Abstract
We introduce the notion of intrinsic subspaces of linear and affine pair geometries, which generalizes the one of projective subspaces of projective spaces. We prove that, when the affine pair geometry is the projective geometry of a Lie algebra introduced in [W. Bertram, K.-H. Neeb, Projective completions of Jordan pairs. I. The generalized projective geometry of a Lie algebra. J. Algebra
277 (2004), 474–519. MR2067615 (2005f:17031) Zbl 02105235], such intrinsic subspaces correspond to inner ideals in the associated Jordan pair, and we investigate the case of intrinsic subspaces defined by the Peirce-decomposition which is related to 5-gradings of the projective Lie algebra. These examples, as well as the examples of general and Lagrangian flag geometries, lead to the conjecture that geometries of intrinsic subspaces tend to be themselves linear pair geometries.
On the relative lengths of the sides of convex polygons
Authors: Su Zhanjun , Ding Ren 
Published: May 2008

Abstract
Doliwka and Lassak proved that if n ≤ 5 then every convex n-gon has a relatively short side and a relatively long side. In this paper we prove that this is true for n ≤ 5 only. More precisely, for any n ≥ 6, there exist n-gons without any relatively short sides.
The structure of full polarized embeddings of symplectic and Hermitian dual polar spaces
Authors: Cardinali Ilaria , De Bruyn Bart 
Published: May 2008

Abstract
Let Δ be a thick dual polar space of rank n ≥ 2 and let e be a full polarized embedding of Δ into a projective space ∑. For every point x of Δ and every i ∈ {0, …, n}, let T
i
(x) denote the subspace of ∑ generated by all points e(y) with d(x, y) ≤ i. We show that T
i
(x) does not contain points e(z) with d(x, z) ≥ i + 1. We also show that there exists a well-defined map ei
x
from the set of (i – 1)-dimensional subspaces of the residue Res Δ(x) of Δ at the point x (which is a projective space of dimension n – 1) to the set of points of the quotient space T
i
(x)/T
i –1 (x). In this paper we study the structure of the maps ei
x
and the subspaces Ti(x) for some particular full polarized embeddings of the symplectic and the Hermitian dual polar spaces. Our investigations allow us to answer some questions asked in the literature.
A Kantor family admitting a normal F-factor constitutes a p-group
Authors: Thas Koen 
Published: May 2008

Abstract
We solve a more general version of a conjecture of D. Hachenberger [D. Hachenberger, Groups admitting a Kantor family and a factorized normal subgroup. Des. Codes Cryptogr.
8 (1996), 135–143. MR1393979 (98c:20042) Zbl 0877.51007] by showing that a group admitting a Kantor family with a thick F-factor is a p-group for some prime p.
An improvement of a theorem of Van de Ven
Authors: Repetto Flavia 
Published: May 2008

Abstract
In this paper we improve a classical result of Van de Ven which characterizes linear subspaces of as the only smooth closed subvarieties of for which the normal sequence splits (see [A. Van de Ven, A property of algebraic varieties in complex projective spaces. In: Colloque
Géom. Diff. Globale (Bruxelles, 1958), 151–152, Centre Belge Rech. Math., Louvain 1959. MR0116361 (22 #7149) Zbl 0092.14004]). Precisely we prove the following: Let X be a submanifold of of dimension ≥ 3, and Y ⊆ X a submanifold of X of dimension ≥ 2. Assume that Span(Y) = Span(X), where Span(X) is the smallest linear subspace of containing X. Then the exact sequence: splits if and only if X is a linear subspace of .
Ample vector bundles with zero loci of small Δ-genera
Authors: Lanteri Antonio , Novelli Carla 
Published: May 2008

Abstract
Let X be a smooth complex projective variety endowed with an ample vector bundle ε admitting a global section whose zero locus is a smooth subvariety Z of the expected dimension, and let H be an ample line bundle on X, whose restriction HZ
to Z is very ample. Triplets (X, ε, H) are studied and classified under the assumption that the delta genus of (Z, HZ
) is either small (≤ 3) or small in comparison with the corank of ε or the degree.
Species composition and seasonal changes in macroalgal blooms in lagoons along the southeastern Gulf of California
Authors: Piñón-Gimate Alejandra , Serviere-Zaragoza Elisa , Ochoa-Izaguirre María Julia , Páez-Osuna Federico 
Published: May 2008

Abstract
Species composition and seasonal changes in macroalgal blooms in six coastal lagoons highly impacted by human activities were tracked for the three seasons between May 2004 and April 2005. Though temperatures were lower during the cold season than during the dry and rainy seasons and some locations showed variations in salinity during the rainy season, nutrient concentrations showed no defined pattern and varied according to season and location. A total of 10 seaweed species and the cyanobacterium Microcoleus lyngbyaceus had biomasses >1 g m-2 dry weight, but only four species represented >1% of the annual biomass. During the dry season, Spyridia filamentosa had the highest biomass (57.5 g m-2). During the rainy season, Gracilaria vermiculophylla was the most conspicuous and abundant species (64.0–291.0 g m-2) and during the cold season, Caulerpa sertularioides had the highest biomass (180.1 g m-2). Abundances of these species were higher than previously reported for this region. Correlation analyses showed a positive correlation between total phosphorus and the biomass of G. vermiculophylla, suggesting that this nutrient might be limiting its growth. C. sertularioides abundance had a positive correlation with N:P ratios, suggesting that high concentrations of nitrogen relative to low phosphorus levels favor its growth. These analyses revealed that nutrient concentrations are most likely to affect macroalgal growth, but temperature and salinity also play a role. This information may be useful for monitoring future blooms and determining changes over time.
Assessment of propeller and off-road vehicle scarring in seagrass beds and wind-tidal flats of the southwestern Gulf of Mexico
Authors: Martin Summer R. , Onuf Christopher P. , Dunton Kenneth H. 
Published: May 2008

Abstract
We used aerial photography and GIS to establish a quantitative baseline of propeller and off-road vehicle (ORV) scarring in seagrass and wind-tidal flats of the upper Laguna Madre in the Padre Island National Seashore (Texas, USA). We also examined scar recovery through comparison of recent (2002, 2005) and historical (1967) aerial photographs of the study area. Scarring intensity was calculated using two different methods. In the first, polygons were visually drawn around groups of scars on digital images. Scarring intensity was estimated as light (<5%), moderate (5–20%), or severe (>20%), based on the total coverage of scars within each polygon (taking into account the length, width, and density of scars). We developed a more objective method that employed creation of vector grid cells and buffers that incorporated the localized ecological impact of scars. Results of spatial and temporal analysis revealed that the polygon approach greatly underestimated the magnitude of scarring. For example, in a single photograph, 7% of seagrass area was lightly scarred according to the polygon method; but light scarring increased to 51% according to grid analysis of the same image. Our results also indicated that propeller scars in Halodule wrightii beds appear to recover in less than three years and ORV tracks have persisted in the wind-tidal flats for at least 38 years. Our approach provides resource managers with procedures for a more objective and efficient assessment of physical disturbances to seagrass and wind-tidal flats caused by boats and ORVs.
Seasonal variation in a deep subtidal Zostera marina L. bed in southern Spain (western Mediterranean Sea)
Authors: Rueda Jose L. , Salas Carmen , Marina Pablo 
Published: May 2008

Abstract
The seasonal variation in biometric and biomass features of a deep subtidal Zostera marina bed (depth 12–14 m) in Cañuelo Bay (southern Spain) was studied through an annual cycle. Shoot density was greatest in September 2004 (402.4±22.01 shoots m-2) and lowest in March 2005 (220.8±51.2 shoots m-2). Shoots with inflorescences were only observed in June 2004, with up to 9.6 fertile shoots m-2. Mean shoot height, leaf width and leaf area index also varied seasonally, with maximum values in June–September and minimum values in December– March. The above-ground (leaf) biomass also varied seasonally, with maximum values in June–September (90–100 g dw m-2) and minimum values in March 2005 (8.4±2.7 g dw m-2). The below-ground (rhizome) biomass remained very stable (90–100 g dw m-2) throughout the year. The deep Z. marina bed in Cañuelo Bay had a similar, but less pronounced, seasonal pattern compared to that observed in shallower beds in temperate areas of the Northern Hemisphere. The rather low attenuation coefficient and stable temperature (14–21°C) of the water column throughout the year may favour the development of eelgrass beds at this depth and in this part of the distribution range.
Short-term indicators of seagrass transplant stress in response to sediment bacterial community disruption
Authors: Milbrandt Eric C. , Greenawalt-Boswell Jaime , Sokoloff Paul D. 
Published: May 2008

Abstract
Bacterial communities in sediments engage in activities that determine the pathways and rates of organic matter remineralization. Changes in bacterial community composition might result in greater restoration success if interactions among seagrasses, sediment, and bacterial communities were elucidated. A manipulative experiment that disrupted the sediment bacterial community examined the response of Thalassia testudinum transplants. Planting units were transported to a suitable location and replanted with either autoclaved, transplant, or donor site sediments. Sediments from the rhizosphere were sub-sampled for analysis of the 16S rDNA gene. The autoclave treatment group had significantly lower bacterial diversity than the other treatments, as measured with terminal restriction fragment length polymorphism. Significantly higher mortality of the transplants was observed in the autoclave treatment group, while mortality in the donor and transplant treatment groups was low relative to the control group. Rhizosphere disruption through the removal of surrounding sediments did not increase mortality, while manipulating the composition of the bacterial community increased mortality in transplants. A native bacterial community was a critical component for minimizing short-term stress associated with a seagrass transplant, which suggests a tighter coupling between seagrasses and sediment bacterial communities than previously thought.