bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Insulin Analog–Induced Lipoatrophy
Authors: Lopez Ximena , Castells Mariana , Ricker Alyne , Velazquez Elsa F. , Mun Edward , Goldfine Allison B.
Published: February 2008

OBJECTIVE—To characterize the pathophysiology of recombinant human insulin-induced lipoatrophy.

RESEARCH DESIGN AND METHODS—We performed immunologic laboratory evaluation and skin testing for different insulin analogs and diluents in patients with type 1 diabetes and severe insulin-induced local lipoatrophy. Subcutaneous adipose tissue biopsies of areas of acute (7 days) and chronic insulin administration were examined. Topical sodium cromolyn was applied twice a day to atrophic areas and prophylactically to new sites of insulin administration.

RESULTS—Subcutaneous adipose biopsies showed an elevated population of tryptase-positive, chymase-positive degranulated mast cells. Of five patients treated with topical sodium cromolyn, none had new lipoatrophic sites and four showed improvements in old lesions.

CONCLUSIONS—Tryptase-positive/chymase-postitive mast cells, known to be sensitive to sodium cromolyn, may contribute to the destructive immune process mediated in response to exogenous insulin. Mast cell stabilizing therapy with topical cromolyn may reverse early and prevent new lipoatrophic lesions.
Clinical Predictors of Disease Progression and Medication Initiation in Untreated Patients With Type 2 Diabetes and A1C Less Than 7%
Authors: Pani Lydie Nkwimi , Nathan David Matthew , Grant Richard William
Published: February 2008

OBJECTIVE—Many patients with early diabetes remain untreated. Our objectives were to identify clinical predictors of 1) worsening glycemic control and 2) medical treatment initiation in response to worsening glycemic control among patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS—We identified 5,804 type 2 diabetic patients seen at least twice between June 2005 and June 2006 within our 12-clinic primary care network. We examined predictors of diabetes progression (A1C ≥7% or initiation of hypoglycemic agent) over a 1-year follow-up period in 705 patients who had A1C <7% and were not on glucose-lowering medications at baseline. In the 200 patients in this group who progressed, we examined predictors of medical therapy initiation.

RESULTS—In multivariate analyses, baseline A1C (P < 0.0001), younger age (P = 0.04), and weight gain (P = 0.03) were independent predictors of progression after adjusting for race, sex, and baseline HDL levels. Each decade of increasing age reduced the risk of progression by 15%. Each 1-lb increase in weight was associated with a 2% increased odds of progression. Likelihood of medication initiation among progressors decreased by 40% (P = 0.02) with every decade of age and decreased by 2.3% (P = 0.02) with each 1-mg/dl decrease in LDL level from baseline after adjusting for race, sex, and weight change.

CONCLUSIONS—Among untreated primary care patients with type 2 diabetes and A1C <7%, younger patients and those with weight gain were more likely to have diabetes progression and should be the focus of aggressive diabetes management.
Coffee Consumption Is Associated With Higher Plasma Adiponectin Concentrations in Women With or Without Type 2 Diabetes
Authors: Williams Catherine J. , Fargnoli Jessica L. , Hwang Janice J. , van Dam Rob M. , Blackburn George L. , Hu Frank B. , Mantzoros Christos S.
Published: February 2008

To test whether the beneficial effects of coffee consumption in metabolism might be explained by changes in circulating levels of adiponectin, we evaluated self-reported habitual coffee and tea consumption and caffeine intake as predictors of plasma adiponectin concentrations among 982 diabetic and 1,058 nondiabetic women without cardiovascular disease from the Nurses' Health Study. Women with and without diabetes who drank ≥4 cups of coffee per day had significantly higher adiponectin concentrations than those who didn't drink coffee regularly (7.7 vs. 6.1 μg/ml, respectively, in diabetic women, P = 0.004; 15.0 vs. 13.2 μg/ml in nondiabetic women, P = 0.04). Similar associations were observed for caffeine intake. We confirm previously reported inverse associations of coffee consumption with inflammatory markers, C-reactive protein, and tumor necrosis factor-α receptor II. Adjustment for adiponectin did not weaken these associations, and adjustment for inflammatory markers did not attenuate the association between coffee consumption and adiponectin concentrations. High consumption of caffeine-containing coffee is associated with higher adiponectin and lower inflammatory marker concentrations.
Incidence and Determinants of Carpal Tunnel Decompression Surgery in Type 2 Diabetes
Authors: Makepeace Ashley , Davis Wendy A. , Bruce David G. , Davis Timothy M.E.
Published: February 2008

To examine the incidence and predictors of carpal tunnel decompression (CTD) in community-based patients with type 2 diabetes, we studied 1,284 type 2 diabetic participants (mean ± SD age 64.1 ± 6.1 years, 49.1% male) in the longitudinal observational Fremantle Diabetes Study who had no history of CTD. A total of 67 participants (5.8%) had a first CTD during 12,109 years (mean 9.4 ± 3.7) of follow-up, an incidence of 5.5 per 1,000 patient-years. This was at least 4.2 times the incidence in the general population (P < 0.001). In Cox proportional hazards analysis, significant independent determinants of first-ever CTD were higher BMI, taking lipid-lowering medication, and being in a stable relationship (P ≤ 0.021). The crude incidence of first CTD is increased in type 2 diabetes and is associated with obesity and sociodemographic/treatment factors that could indicate treatment-seeking behavior including CTD in symptomatic patients.
School Adjustment in the Early Grades: Toward an Integrated Model of Neighborhood, Parental, and Child Processes
Authors: Nettles Saundra Murray , Caughy Margaret O’Brien , O’Campo Patricia J.
Published: February 2008

Examining recent research on neighborhood influences on child development, this review focuses on social influences on school adjustment in the early elementary years. A model to guide community research and intervention is presented. The components of the model of integrated processes are neighborhoods and their effects on academic outcomes and neighborhoods as moderators of effects of parental behavior on school-related outcomes. The findings on neighborhood risk factors as moderators of the association between school adjustment and family and child risks are also considered. The review concludes with a summary and a discussion of gaps in the literature of contextual factors and child outcomes.
Polyetheretherketone Films with Low Thermal Expansion for Flexible Printed Circuit Boards
Authors: Seidel C. , Muenstedt H.
Published: February 2008

Rigid and flexible circuit boards consist of layers of different materials. Particularly, the different thermal expansion coefficients of thermoplastic polymers and metals can lead to problems during application. The investigations presented are focused on the high-temperature thermoplastic polyetheretherketone (PEEK), as it has a remarkable potential for novel flexible circuit boards. The work shows the significant thermal expansion reductions that can be reached in a thermoplastic polyetheretherketone (PEEK) film by the incorporation of different contents of calcium carbonate or talc fillers and compares their effectiveness. Particularly the influence of filler geometry on the thermal expansion is studied in detail. The effect of the filling on mechanical properties and the dimensional stability of the PEEK films under thermal load is investigated quantitatively.
Floral costs in Nigella sativa (Ranunculaceae): compensatory responses to perianth removal
Authors: Andersson Stefan
Published: February 2008

Because internal resources are finite, it has been assumed that attractive, floral organs represent a significant drain on the energy and nutrient budget of a plant. Despite the broad significance of such trade‐offs, in relatively few studies have investigators manipulated floral investments, then evaluated allocation to subsequently produced flowers, fruits, and seeds. In the present study of Nigella sativa, the cost of maturing and/or maintaining perianths was documented after all sepals and nectaries were removed at the bud stage and a significant increase in mean seed mass, the total amount of biomass allocated to seed production, and mean germination rate of the maternal seed crop were measured. The increased biomass, carbon, and nitrogen allocated to seeds were similar in magnitude to the reduction in biomass, carbon, and nitrogen invested in sepals and nectaries after perianth removal. Perianth removal did not significantly affect flower production, maternal fecundity, or progeny seed number. Taken together, these observations indicate the potential for selection—mediated through resource trade‐offs with seed mass and time to germination—to cause, or at least facilitate, evolutionary reductions in flower size.
The role of fungal pathogens in flower size and seed mass variation in three species of Hydrophyllum (Hydrophyllaceae)
Authors: Marr Deborah L , Marshall Michelle L
Published: February 2008

Identifying ecological factors that affect seed number and seed size is key to understanding the persistence of large seed mass variation in some plant species. Pathogens may increase seed mass variation by increasing resource demand over the growing season such that late fruits experience higher resource competition than early fruits. We tested whether Fusarium sp. and Rhizoctonia sp., soil fungi that cause wilt, contributed to seasonal decline in flower size, seed number, or seed mass in Hydrophyllum appendiculatum and H. canadense. A third species not infected by these soil fungi, H. virginianum, was studied to determine how seasonal decline in floral traits and seed mass variation varies within this genus. Flower size declined seasonally for all species, but was greatest for H. appendiculatum, a monocarpic biennial with indeterminate inflorescences. Seed number decreased between first and last inflorescences in H. appendiculatum, but not in H. canadense or H. virginianum, perennials with determinate inflorescences. Seed mass varied most in H. appendiculatum and H. canadense (4–20‐fold in 50% of individuals) and least in H. virginianum (4–8‐fold in >30% of individuals). Fungal infection increased seed mass variation among diseased plants in H. canadense and H. appendiculatum. However, within plants fungal infection only increased seasonal decline in flower size, seed number, and seed mass in H. appendiculatum when flowers received supplemental pollination.
Molecular phylogeography and hybridization in members of the circumpolar Potentilla sect. Niveae (Rosaceae)
Authors: Eriksen Bente , Töpel Mats H
Published: February 2008

Glacial events and the formation of ice‐free areas serving as refugia for plants and animals are important in shaping present patterns of genetic diversity in arctic areas. Beringia, situated in northeastern Russia and Alaska, has been pointed out as a major refugium. This study focuses on the historical biogeography of the circumpolar taxon Potentilla sect. Niveae. The taxonomy of the group is complex, most likely highly influenced by hybridization and apomixis. cpDNA microsatellites together with AFLP fragments were used to map the genetic variability in the section, from Beringia across the Canadian Arctic to Greenland. The data support the hypothesis that Beringia, as well as parts of adjacent arctic Canada, served as refugia during the Wisconsinan glaciation, and there is some evidence for a northern and a southern migration route out of Beringia. The hair type groups within sect. Niveae are more or less genetically distinct, and hybridization, especially with sect. Multifida, takes place. Haplotype diversity as well as frequency is at its maximum close to the Last Glacial Maximum ice cap edge. This pattern can be explained by merging of previously isolated refugia, by repeated extinction/colonization events close to the ice edge, and by hybridization among sympatric taxonomical lineages.
The structure of xylem vessels in grapevine (Vitaceae) and a possible passive mechanism for the systemic spread of bacterial disease
Authors: Thorne Eleanor T. , Young Briana M. , Young Glenn M. , Stevenson Joshua F. , Labavitch John M. , Matthews Mark A. , Rost Thomas L.
Published: February 2008

Xylem‐dwelling pathogens become systemic, suggesting that microorganisms move efficiently in the xylem. To better understand xylem pathways and how bacteria move within the xylem, vessel connectivity between stems and leaves of Vitis vinifera cv. Chardonnay and Muscadinia rotundifolia cv. Cowart was studied. Three methods were used: (1) the light‐producing bacterium, Yersinia enterocolitica, (Ye) strain GY5232 was loaded into petioles and followed using X‐ray film, (2) fluorescent beads were loaded and followed by microscopy, and (3) low‐pressure air was pumped into leaves and extruded bubbles from cuts in submerged leaves were followed. Bacteria, beads, and air moved through long and branched xylem vessels from the petiole into the veins in leaves of both varieties. From the stem, bacteria and air traveled into primary and secondary veins of leaves one, two, and three nodes above the loading point of the bacteria or air. Particles and air could move unimpeded through single xylem vessels or multiple vessels (conduits) connected possibly through broken pit membranes from within the stem axis into leaf blades. Bacteria were also able to move long distances within minutes from stem to leaf passively without having to cross pit membranes. Such complex, open xylem conduits have not been well documented before; these findings will help elucidate mechanisms involved in the systemic spread of pathogens.
A new herbarium‐based method for reconstructing the phenology of plant species across large areas
Authors: Lavoie Claude , Lachance Daniel
Published: February 2008

Phenological data have recently emerged as particularly effective tools for studying the impact of climate change on plants, but long phenological records are rare. The lack of phenological observations can nevertheless be filled by herbarium specimens as long as some correction procedures are applied to take into account the different climatic conditions associated with sampling locations. In this study, we propose a new herbarium‐based method for reconstructing the flowering dates of plant species that have been collected across large areas. Coltsfoot (Tussilago farfara L.) specimens from southern Quebec were used to test the method. Flowering dates for coltsfoot herbarium specimens were adjusted according to the date of disappearance of snow cover in the region where they were collected and compared using a reference point (the date of earliest snowmelt). In southern Quebec, coltsfoot blooms earlier at present (15–31 d) than during the first part of the 20th century. This phenomenon is likely associated with the climate warming trends recorded in this region in the last century, especially during the last three decades when the month of April became warmer, thereby favoring very early‐flowering cases. The earlier flowering of coltsfoot is, however, only noticeable in large urban areas (Montreal, Quebec City), suggesting a strong urban heat island effect on the flowering of this plant. Herbarium specimens are useful phenological indicators; however, the databases should be carefully examined prior to analysis to detect biases or trends associated with sampling locations.
Spatial genetic structure and frequency of interspecific hybridization inPlatanthera aquilonisandP. dilatata(Orchidaceae) occurring in sympatry
Authors: Wallace Lisa E.
Published: February 2008

Knowledge of genetic structure at different scales is necessary for evaluating the importance of interactions between the genome and environment and for inferring underlying processes that bring about evolutionary diversification. Here, genetic and morphological variation was assessed for 154 individuals ofPlatanthera aquilonisandP. dilatatain Maine, using RAPD and PCR‐RFLP markers and measurements of five morphological traits to determine the prevalence of interspecific hybrids and underlying spatial genetic structure of the population. Both species co‐mingled in the population, but clumping was observed.Platanthera aquiloniswas more abundant, but genetic variation was lower (polymorphic loci [40%], expected heterozygosity [0.137]) than that ofP. dilatata(Pp= 72%;He= 0.245). Interspecific hybrids were rare (eight individuals), and morphology was not consistently reliable for determining hybrid status even though the species differed significantly in several traits. Spatial autocorrelation analyses showed significant genetic structure at small distances for both species, most likely due to restricted seed dispersal.Platanthera aquilonisdid not exhibit a pattern of spatial genetic structure consistent with other selfing species. This suggests that the species is facultative autogamous, which allows for limited production of hybrid individuals and reduces the strength of spatial genetic structure relative toP. dilatata.
The evolutionary history ofMelianthus(Melianthaceae)
Authors: Linder H. Peter , Dlamini Titus , Henning Jack , Verboom G. Anthony
Published: February 2008

The evolutionary origins of the morphological and taxonomic diversity of angiosperms is poorly known. We used the genusMelianthusto explore the diversification of the southern African flora.Melianthuscomprises eight species, and a phylogeny based on one nuclear and two plastid genes, as well as a morphological data set, confirmed that the genus is monophyletic. The two earliest diverging lineages are found in relatively mesic habitats, whereas the two terminal clades (an eastern and a western clade), each with three species, favor more arid habitats. The eastern clade is largely restricted to the summer‐rainfall parts of southern Africa, and the western clade is found in winter‐rainfall region. Molecular dating indicates a mid‐Tertiary origin of the genus, with diversification of the eastern and western clades coincident with the Late Miocene–Pliocene uplift of the Escarpment mountains and the establishment of summer aridity along the west coast. The remarkably complex flowers are indicative of sunbird pollination, but many smaller birds can also visit. Speciation may be the consequence of allopatric divergence into edaphic–climatic niches. Divergence in flower and inflorescence morphology might be in response to the divergent pressures for nectar conservation in arid regions coupled with the need for signaling to avian pollinators in generally shrubby vegetation.
One hundred years of American botany: a short history of the Botanical Society of America
Authors: Smocovitis Vassiliki Betty
Published: February 2008

This paper offers highlights from the 100 (plus) years of the Botanical Society of America (BSA) and draws extensively on the archives of the BSA. In addition to examining the founding of the society and the attempt to “professionalize” botany in late 19th century America, the paper also explores the complex relations between the BSA and a number of related societies in the United States, the Society's struggle to create a coherent identity for itself, the place of botany as a whole in the context of the burgeoning biological sciences in the 20th century, and the changing role of the BSA in an international context. The paper assesses both the achievements and the challenges facing the BSA. It closes by offering some historical reflections on the status of “botany” as a science and the historical significance of terms like “plant biology” and “plant science.”
The pollination biology of Burmeistera (Campanulaceae): specialization and syndromes
Authors: Muchhala Nathan
Published: February 2008

The floral traits of plants with specialized pollination systems both facilitate the primary pollinator and restrict other potential pollinators. To explore interactions between pollinators and floral traits of the genus Burmeistera, I filmed floral visitors and measured pollen deposition for 10 species in six cloud forest sites throughout northern Ecuador. Nine species were primarily bat‐pollinated (84–100% of pollen transfer); another (B. rubrosepala) was exclusively hummingbird‐pollinated. According to a principal components analysis of 11 floral measurements, flowers of B. rubrosepala were morphologically distinct. Floral traits of all species closely matched traditional ornithophilous and chiropterophilous pollination syndromes; flowers of B. rubrosepala were bright red, lacked odor, opened in the afternoon, and had narrow corolla apertures and flexible pedicels, which positioned them below the foliage. Flowers of the bat‐pollinated species were dull‐colored, emitted odor, opened in the evening, and had wide apertures and rigid pedicels, which positioned them beyond the foliage. Aperture width appeared most critical to restricting pollination; hummingbirds visited wide flowers without contacting the reproductive parts, and bats did not visit the narrow flowers of B. rubrosepala. Aperture width may impose an adaptive trade‐off that favors the high degree of specialization in the genus. Other floral measurements were highly variable amongst bat‐pollinated species, including stigma exsertion, calyx lobe morphology, and pedicel length. Because multiple species of Burmeistera often coexist, such morphological diversity may reduce pollen competition by encouraging pollinator fidelity and/or spatially partitioning pollinator's bodies.
Phenotypic plasticity and mechanical stress: biomass partitioning and clonal growth of an aquatic plant species
Authors: Puijalon Sara , Bornette Gudrun
Published: February 2008

Mechanical stresses from wind, current or wave action can strongly affect plant growth and survival. Survival and distribution of species often depend on the plant's capacity to adapt to such stresses, particularly when amplified by climatic variations. Few studies have dealt with plastic adjustments in response to mechanical stress compared to resource stress. We hypothesized that mechanical stress should favor plastic adjustments that result in increased biomass production in zones protected from the stress and that altered growth patterns should be reversible after mechanical stress removal. Here we measured plastic adjustments in morphological traits and clonal architecture for an aquatic clonal species (Berula erecta) under two contrasting mechanical stresses in the field—standing vs. running water. Reversion of the morphological changes was then assessed using transplants in standing water. In the case of mechanical stress, size reduction, biomass reallocation within clones (higher allocations to clonal growth and to belowground organs), and a more compact growth form (reduced spacer lengths) contributed to reducing the damage risk. The removal of mechanical stress induced compensatory growth, probably linked to the production of low density tissues. However, most patterns of dry mass partitioning induced by current stress were not reversed after stress removal.
Phylogenetics of the florally diverse Andean clade Iochrominae (Solanaceae)
Authors: Smith Stacey DeWitt , Baum David A.
Published: February 2008

Recent molecular phylogenetic studies of Solanaceae have identified many well‐supported clades within the family and have permitted the creation of a phylogenetic system of classification. Here we estimate the phylogeny for Iochrominae, a clade of Physaleae sensu Olmstead et al. (1999), which contains 34 Andean species encompassing an immense diversity of floral forms and colors. Using three nuclear regions, ITS, the second intron of LEAFY, and exons 2 to 9 of the granule‐bound starch synthase gene (waxy), we evaluated the monophyly of the traditional genera comprising Iochrominae and assessed the extent of interspecific hybridization within the clade. Only one of the six traditionally recognized genera of Iochrominae was supported as monophyletic. Further, comparison of the individual nuclear data sets revealed two interspecific hybrid taxa and a third possible case. These hybrid taxa occur in the Amotape–Huancabamba zone, a region between the northern and central Andes that has the greatest diversity of Iochroma species and offers frequent opportunities for hybridization in areas of sympatry. We postulate that periodic hybridization events in this area coupled with pollinator‐mediated selection and the potential for microallopatry may have acted together to promote diversification in montane Andean taxa, such as Iochrominae.
Infrageneric phylogeny of Schoenocaulon (Liliales: Melanthiaceae) with clarification of cryptic species based on ITS sequence data and geographical distribution
Authors: Zomlefer Wendy B. , Whitten W. Mark , Williams Norris H. , Judd Walter S.
Published: February 2008

As currently defined, the 24 species of Schoenocaulon occur in three disjunct areas: north central Florida (one species, S. dubium), southern Peru (portion of the range of S. officinale), and the region from southeastern New Mexico–Texas south to Venezuela; the 20 species endemic to Mexico are geographically restricted. Species delimitations, often based on tepal morphology, have been problematic. Our analyses of ITS sequence data for all 27 species and infraspecific taxa support recognition of two new species and recircumscription and placement of elements of the polyphyletic S. ghiesbreghtii and S. mortonii complexes. For taxa with adequate sampling, our data also indicate 11–12 cladospecies and 3–6 metaspecies according to the apomorphic species concept. The resolved phylogeny, correlated with geography and morphology, allows insight into biogeographical diversification and the evolution of some unusual morphological characters within the genus, such as nectary differentiation and tepal margin type.
Phytolaccaceae infructescence from Cerro del Pueblo Formation, Upper Cretaceous (late Campanian), Coahuila, Mexico
Authors: Cevallos‐Ferriz Sergio R. S. , Estrada‐Ruiz Emilio , Pérez‐Hernández Balam Rodrigo
Published: February 2008

The Upper Cretaceous (late Campanian) Cerro del Pueblo Formation, Coahuila, Mexico, contains a diverse group of angiosperms represented mainly by their reproductive structures. Among these, a new permineralized infructescence is recognized based on its morphological and anatomical characters. It is a multiple infructescence composed of berry fruits with six locules, each containing a single seed with a curved embryo developed from a campylotropous ovule with pendulous placentation; integumentary anatomy is similar to that of Phytolacca spp. (Phytolaccaceae). Though this new plant from Coahuila shares reproductive characters with Phytolacca, the constant number (six) of carpels per fruit and pendulous placentation strongly support the recognition of a new taxon, Coahuilacarpon phytolaccoides Cevallos‐Ferriz, Estrada‐Ruiz, et Pérez‐Hernández (Phytolaccaceae, Caryophyllales). This new record adds to the known plant diversity of low latitude North America (northern Mexico) and demonstrates the long geologic history of the group.
Hybrid Organic‐Inorganic Materials from Di‐(2‐pyridyl)methylamine‐Palladium Dichloride Complex as Recoverable Catalysts for Suzuki, Heck and Sonogashira Reactions
Authors: Trilla Montserrat , Pleixats Roser , Man Michel Wong Chi , Bied Catherine , Moreau Joël J. E.
Published: February 2008

Hybrid silica materials containing the di‐(2‐pyridyl)methylamine‐palladium dichloride complex, prepared by sol‐gel cogelification, are efficient recyclable catalysts for Suzuki (aryl bromides and chlorides), Heck (aryl bromides) and Sonogashira reactions (aryl iodides and bromides). Formation of palladium(0) nanoparticles is observed in the Suzuki and Heck reactions but not in the Sonogashira coupling.
Adenosine A2A receptor antagonists exert motor and neuroprotective effects by distinct cellular mechanisms
Authors: Yu Liqun , Shen Hai‐Ying , Coelho Joana E. , Araújo Inês M. , Huang Qing‐Yuan , Day Yuan‐Ji , Rebola Nelson , Canas Paula M. , Rapp Erica Kirsten , Ferrara Jarrod , Taylor Darcie , Müller Christa E. , Linden Joel , Cunha Rodrigo A. , Chen Jiang‐Fan
Published: February 2008

Objective

To investigate whether the motor and neuroprotective effects of adenosine A2A receptor (A2AR) antagonists are mediated by distinct cell types in the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) model of Parkinson's disease.

Methods

We used the forebrain A2AR knock‐out mice coupled with flow cytometric analyses and intracerebroventricular injection to determine the contribution of A2ARs in forebrain neurons and glial cells to A2AR antagonist‐mediated motor and neuroprotective effects.

Results

The selective deletion of A2ARs in forebrain neurons abolished the motor stimulant effects of the A2AR antagonist KW‐6002 but did not affect acute MPTP neurotoxicity. Intracerebroventricular administration of KW‐6002 into forebrain A2AR knock‐out mice reinstated protection against acute MPTP‐induced dopaminergic neurotoxicity and attenuated MPTP‐induced striatal microglial and astroglial activation.

Interpretation

A2AR activity in forebrain neurons is critical to the control of motor activity, whereas brain cells other than forebrain neurons (likely glial cells) are important components for protection against acute MPTP toxicity. Ann Neurol 2008
A new amyloid β variant favoring oligomerization in Alzheimer's‐type dementia
Authors: Tomiyama Takami , Nagata Tetsu , Shimada Hiroyuki , Teraoka Rie , Fukushima Akiko , Kanemitsu Hyoue , Takuma Hiroshi , Kuwano Ryozo , Imagawa Masaki , Ataka Suzuka , Wada Yasuhiro , Yoshioka Eito , Nishizaki Tomoyuki , Watanabe Yasuyoshi , Mori Hiroshi
Published: February 2008

Objective

Soluble oligomers of amyloid β (Aβ), rather than amyloid fibrils, have been proposed to initiate synaptic and cognitive dysfunction in Alzheimer's disease (AD). However, there is no direct evidence in humans that this mechanism can cause AD. Here, we report a novel amyloid precursor protein (APP) mutation that may provide evidence to address this question.

Methods

A Japanese pedigree showing Alzheimer's‐type dementia was examined for mutations in APP, PSEN1, and PSEN2. In addition, 5,310 Japanese people, including 2,121 patients with AD, were screened for the novel APP mutation. The pathogenic effects of this mutation on Aβ production, degradation, aggregation, and synaptotoxicity were also investigated.

Results

We identified a novel APP mutation (E693Δ) producing variant Aβ lacking gulutamate‐22 (E22Δ) in Japanese pedigrees showing Alzheimer's‐type dementia and AD. Although the secretion of total Aβ was markedly reduced by this mutation, the variant Aβ was more resistant to proteolytic degradation. The mutant peptides showed the unique aggregation property of enhanced oligomerization but no fibrillization, and inhibited hippocampal long‐term potentiation more potently than wild‐type peptide in rats in vivo. Consistent with the nonfibrillogenic property of the variant Aβ, a very low amyloid signal was observed in the patient's brain on positron emission tomography using Pittsburgh compound‐B.

Interpretation

The E693Δ mutation has been suggested as a cause of dementia because of enhanced formation of synaptotoxic Aβ oligomers. Our findings may provide genetic validation in humans for the emerging hypothesis that the synaptic and cognitive impairment in AD is primarily caused by soluble Aβ oligomers. Ann Neurol 2008
Effect of phenserine treatment on brain functional activity and amyloid in Alzheimer's disease
Authors: Kadir Ahmadul , Andreasen Niels , Almkvist Ove , Wall Anders , Forsberg Anton , Engler Henry , Hagman Göran , Lärksäter Marie , Winblad Bengt , Zetterberg Henrik , Blennow Kaj , Långström Bengt , Nordberg Agneta
Published: February 2008

Objective

The effects of (−)‐phenserine (phenserine) and placebo/donepezil treatment on regional cerebral metabolic rate for glucose (rCMRglc) and brain amyloid load were investigated by positron emission tomography in 20 patients with mild Alzheimer's disease in relation to cerebrospinal fluid (CSF) and plasma biomarkers, and cognitive function.

Methods

The first 3 months of the study was a randomized, double‐blind, placebo‐controlled phase, during which 10 patients received phenserine (30mg/day) and 10 patients the placebo. Three to 6 months was an open‐label extension phase, during which the placebo group received donepezil (5mg/day) and the phenserine group remained on phenserine. After 6 months, all patients received phenserine treatment up to 12 months. The patients underwent positron emission tomography examinations to measure rCMRglc (18F‐FDG) and amyloid load (11C‐PIB) at baseline and after 3 and 6 months of the treatment. Neuropsychological and biomarker data were collected at the three times of positron emission tomography imaging.

Results

Statistically significant effects on a composite neuropsychological test score were observed in the phenserine‐treated group compared with the placebo and donepezil group at 3 and 6 months, respectively. Values of rCMRglc were significantly increased in several cortical regions after 3 months of phenserine treatment, compared with baseline, and correlated positively with cognitive function and CSF β‐amyloid 40 (Aβ40). Cortical Pittsburgh Compound B retention correlated negatively with CSF Aβ40 levels and the ratio Aβ/β‐secretase–cleaved amyloid precursor protein. In CSF, Aβ40 correlated positively with the attention domain of cognition.

Interpretation

Phenserine treatment was associated with an improvement in cognition and an increase in rCMRglc. Ann Neurol 2008
Nanocrystallite regions of guar gum filled PU/PAN composites before and after biodegradation using WAXS
Authors: Kumar H. , Siddaramaiah  , Somashekar R. , Mahesh S. S. , Manjunath A.
Published: February 2008

Polyurethane/polyacrylonitrile semi‐interpenetrating polymer network containing varying weight percent of guar gum were prepared. The resulting composites were subjected to biodegradation with the help of specific fungi Aspergillus niger. The composite before and after biodegradation were subjected to wide angle X‐ray scattering studies. The nanocrystallite regions, area, and size are determined from X‐ray data using three different asymmetric column length functions. A comparison of these parameters does explain the nature of biodegradation at microlevel. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of porous materials by 2‐nitroresorcinol/cyanuric chloride thermal polycondensation in emulsions
Authors: Audouin Fabrice , Birot Marc , Pasquinet Éric , Deleuze Hervé , Besnard Olivier , Poullain Didier
Published: February 2008

Rigid monoliths were prepared from concentrated oil in water (O/W) emulsions by a base‐catalyzed polycondensation reaction of 2‐nitroresorcinol with cyanuric chloride. Mercury intrusion/extrusion porosimetry confirmed that the obtained monoliths were porous with an open porosity. However, scanning electron microscopy showed that the structure of these materials was different from that of emulsion‐derived materials previously described in the literature [polymerized high internal phase emulsions (polyHIPEs)]. In comparison with polystyrene/divinylbenzene‐based polyHIPEs obtained by radical polymerization, these materials exhibited a higher skeletal density, and thermogravimetric analysis and differential scanning calorimetry analysis indicated that they were more thermally stable. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
In situ pH‐decrease‐induced gelation of sodium alginate/carboxymethylated konjac glucomannan
Authors: Gao Shanjun , Wu Chengdong , Nishinari Katsuyoshi
Published: February 2008

The gelation kinetics and rheological properties of a mixture system containing two anionic polysaccharides, sodium alginate and carboxymethylated konjac glucomannan, in the presence of glucono‐delta‐lactone were investigated with dynamic viscoelastic measurements. The slow release of protons induced by glucono‐delta‐lactone gave birth to partly uncharged polymer chains and partly shielded electrostatic repulsion, resulting in an interpolymer association. This segregative interaction brought about a significant improvement in the elastic modulus of the resultant gel. The strongest synergism occurred at a carboxymethylated konjac glucomannan concentration of 29.9 wt %, exhibiting the highest gel strength. Increasing the content or the degree of substitution of carboxymethylated konjac glucomannan resulted in slower gelation kinetics. The fractal dimension of the incipient gel, which was not greatly affected by the mixing ratio or the degree of substitution of carboxymethylated konjac glucomannan, reflected a rather compact gel structure network. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Conductivity and structure of a polyamide/silver iodide nanocomposite
Authors: Fujimori Yoshie , Gotoh Yasuo , Kawaguchi Akio , Ohkoshi Yutaka , Nagura Masanobu
Published: February 2008

In this study, the structure and properties of an organic–inorganic composite material prepared from nylon 6 doped with fine particles of silver iodide (AgI) were examined. The preparation of the composite involved the complexation of nylon 6 with polyiodide ions such as I and I by immersion in an iodine/potassium iodide (I2–KI) aqueous solution followed by reaction in a silver nitrate (AgNO3) aqueous solution; this resulted in the in situ formation of β‐AgI fine particles within the nylon 6 matrix. The AgI content formed in the composite was dependent on the immersion temperatures of the I2–KI and AgNO3 solutions. Lower solution temperatures resulted in larger amounts of AgI in the composite. This method readily provided a composite with a high content of AgI in nylon 6 and a conductivity of approximately 10−5 Ω−1 cm−1. In a uniaxially oriented nylon 6 matrix, AgI particles precipitated with anisotropic shape, which was caused by the orientation of the precursor polyiodide ions. The structure of the oriented composite provided the anisotropic conductivity. Additionally, the composite exhibited high antibacterial properties. The procedure used in this study is considered a unique method for the preparation of organic–inorganic composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Green and self‐lubricating polyoxymethylene composites filled with low‐density polyethylene and rice husk flour
Authors: Li Ke , Xiang Dinghan , Lei Xiaoyu
Published: February 2008

Polyoxymethylene (POM) composites filled with low‐density polyethylene (LDPE) and rice husk flour (RHF) were prepared by injection molding. The POM/5 wt % LDPE/7.5 wt % RHF composite exhibited the lowest wear rate, whereas the coefficient of friction remained low, and the POM/5 wt % LDPE/5 wt % RHF composite had the best mechanical properties. X‐ray diffraction analysis was carried out, and the worn surfaces were examined with scanning electron microscopy. The results showed that the addition of the filler reduced the crystallinity degree of the POM composites. The main wear mechanism for unfilled POM was adhesion, whereas for the POM composites, wear seemed to occur mainly by fatigue and abrasion. It was experimentally confirmed that the POM composite filled with LDPE and RHF, which is well‐performing, low‐cost, and environmentally friendly, could be a potential material for tribological applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Morphology and barrier properties of nanobiocomposites of poly(3‐hydroxybutyrate) and layered silicates
Authors: Sanchez‐Garcia M. D. , Gimenez E. , Lagaron J. M.
Published: February 2008

Polyhydroxybutyrate (PHB) is generally considered to be a very uneasy biopolymer to handle because of significant instability during melt processing and some excessive brittleness. This work studied the morphological, thermal, and barrier properties of novel melt‐mixed nanobiocomposites of PHB, poly(ε‐caprolactones) (PCL), and layered phyllosilicates based on commercial organomodified kaolinite and montmorillonite clay additives. The addition of PCL component to the blend was seen to reduce oxygen permeability but it was also found to lead to a finer dispersion of the clay. The addition of highly intergallery swollen organomodified montmorillonite clays to the PHB blend led to a highly dispersed morphology of the filler, but this simultaneously increased to a significant extend the melt instability of the biopolymer. Nevertheless, the organomodified kaolinite clay, despite the fact that it was found to both lead to less dispersed and irregular morphology, particularly for higher clay loadings, it led to enhanced barrier properties to oxygen, D‐limonene, and water. D‐limonene and specially water molecules were, however, found to sorb in both hydrophobic and hydrophilic sites of the filler, respectively, hence diminishing the positive barrier effect of an enlarged tortuosity factor in the permeability. Mass transport properties were found to depend on the type of penetrant and modeling of the permeability data to most commonly applied formalisms was not found to be satisfactory because of factors such as morphological alterations, heterogeneity in the clay dispersion, and penetrant solubility in the filler. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Tribological testing of peroxide cured HNBR with different MWCNT and silica contents under dry sliding and rolling conditions against steel
Authors: Felhös D. , Karger‐Kocsis J. , Xu D.
Published: February 2008

The sliding, and rolling friction and wear behaviors of peroxide cured hydrogenated nitrile rubber (HNBR) with 10 and 30 parts per hundred rubber (phr) multiwall carbon nanotube (MWCNT) and silica, respectively, were investigated. Mechanical properties (hardness, tensile modulus, ultimate tensile strength and strain, tear strength) of the rubbers were determined. Dynamic‐mechanical thermal analysis was also performed and the apparent crosslink density estimated. Tribological properties were investigated in pin (steel)‐on‐plate (rubber), with roller (steel)‐on‐plate (rubber), with oscillating steel cylinder on rubber plate (Fretting) and with rolling ball (steel)‐on‐plate (rubber) (RBOP) test configurations. Coefficient of friction and specific wear rate (Ws) of the HNBR systems were determined. It was established that the resistance to wear increases with increasing filler content, and the incorporation of MWCNT was more advantageous than silica from the viewpoint of dry sliding and rolling performance. The friction and wear characteristics strongly depended on the test configurations. The worn surface of the HNBR systems was inspected in scanning electron microscope to conclude the typical wear mechanisms which were discussed accordingly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and electrorheological activity of a modified kaolinite/carboxymethyl starch hybrid nanocomposite
Authors: Zhao Xiaopeng , Wang Baoxiang , Li Jia
Published: February 2008

According to physical and chemical designs, a novel modified kaolinite/carboxymethyl starch (CMS) nanocomposite was synthesized with a displacement method with dimethyl sulfoxide modified kaolinite as an intermediate. The material characterizations were carried out by X‐ray diffraction, transmission electron microscopy, thermogravimetric analysis, and scanning electron microscopy. The analyses showed that kaolinite was dispersed at the nanometer‐scale segments into the CMS matrix. The electrorheological behavior of the modified kaolinite/CMS hybrid nanocomposite dispersed in silicone oil was investigated. Under electric field strength (E) = 4 kV/mm and shear rate , the shear stress of the modified kaolinite/CMS nanocomposite electrorheological fluid could be up to 8380 Pa, which was 10.4 times that of the electrorheological fluid at zero field. The modified kaolinite/CMS nanocomposite electrorheological fluid also exhibited good sedimentation properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of different functionalized multiwall carbon nanotubes on the mechanical properties of poly(ethylene terephthalate) fibers
Authors: Shen Liming , Gao Xushan , Tong Yan , Yeh Andrew , Li Ruixia , Wu Dacheng
Published: February 2008

Master batches with four different kinds of functionalized multiwall carbon nanotubes (MWCTs) were prepared through the mixing of MWCTs with poly(ethylene terephthalate) (PET) (0.01 : 0.99 w/w) in trifluoroacetic acid/dichloromethane mixed solvents (0.7 : 0.3 v/v) followed by the removal of the solvents in the mixture by flocculation. The results of scanning electron microscopy showed that a good dispersion of MWCTs in PET was achieved. The reinforced fibers were fabricated by the melt spinning of PET chips with small amounts of the master batch and then further postdrawing. The optimal spinning conditions for the reinforcement of fibers were a 0.6‐mm spinneret hole and a 250 m/min wind‐up speed. Among the four master batches, the fibers obtained from PET/master batch B made by acid‐treatment had the highest enhancement of mechanical properties. For a 0.02 wt % loading of acid‐treated MWCT, the breaking strength of the PET/master batch B composite fibers increased by 36.9% (from 4.45 to 6.09 cN/dtex), and the initial modulus increased by 41.2% (from 80.7 to 113.9 cN/dtex). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Prediction of lateral lymph node metastases in medullary thyroid cancer
Authors: Machens A , Hauptmann S , Dralle H
Published: February 2008

Background

In medullary thyroid cancer (MTC), there is a concordance between central and lateral neck involvement, but this relationship has not been assessed quantitatively.

Methods

After compartment-oriented lymphadenectomy for untreated MTC, the numbers of central lymph node metastases with ipsilateral (195 patients) and contralateral (185 of 195 patients) lateral lymph node metastases were analysed retrospectively.

Results

With one to three positive central lymph nodes, involvement of the ipsilateral lateral neck increased from 10·1 per cent (with no central node involvement) to 77 per cent, and from a mean of 0·6 to 3·7 nodal metastases (P < 0·001). With four or more central nodes, the rate was 98 per cent, with 10·7 nodal metastases (P = 0·001). A weaker increase was observed in the contralateral lateral neck: with one to nine positive central nodes, contralateral lateral neck involvement increased from 4·9 to 38 per cent, and from a mean of 0·6 to 2·3 nodal metastases (P = 0·011). With ten or more positive central nodes, the rate rose to 77 per cent, with 6·2 nodal metastases (P = 0·009). With one exception, contralateral lateral nodal metastases coexisted with metastases in the central and ipsilateral lateral neck.

Conclusion

These data may lay the groundwork for more informed decision-making regarding dissection of the lateral neck compartments.
Prognostic significance of extracapsular lymph node involvement in patients with adenocarcinoma of the ampulla of Vater
Authors: van der Gaag N A , ten Kate F J W , Lagarde S M , Busch O R C , van Gulik T M , Gouma D J
Published: February 2008

Background

Lymphatic dissemination is an important predictor of survival in patients with adenocarcinoma of the ampulla of Vater. The incidence and clinical consequences of extracapsular lymph node involvement (LNI) in patients who undergo resection are unknown.

Methods

In a consecutive series of 160 patients with adenocarcinoma of the ampulla of Vater, 75 (46·9 per cent) had positive lymph nodes (N1). The relation of extracapsular LNI with tumour stage and number of positive nodes was evaluated and its prognostic significance analysed.

Results

Extracapsular LNI was identified in 44 (59 per cent) of the 75 patients. Median overall survival was 30 and 18 months in patients with intracapsular and extracapsular LNI respectively (P = 0·015). The 5-year overall survival rate was 20 and 9 per cent respectively, compared with 59 per cent in patients without LNI (N0). Extracapsular LNI and tumour differentiation were independent prognostic factors for survival. In patients with N1 disease, extracapsular LNI was the only significant prognostic factor for recurrent disease after radical resection (R0).

Conclusion

The presence of extracapsular LNI identifies a subgroup of patients who have a significantly worse prognosis. Adjuvant therapy is advised following resection in these patients.