bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quasistatic and continuous dynamic characterization of the mechanical properties of silk from the cobweb of the black widow spiderLatrodectus hesperus
Authors: Blackledge Todd A. , Swindeman John E. , Hayashi Cheryl Y. 
Published: May 2005

SUMMARYSpider silks are among the strongest and toughest known materials, but investigation of these remarkable properties has been confined largely to orb-weaving spiders. We investigated the mechanical performance of silk from the cobweb-weaving spider Latrodectus hesperus. Both silk from the scaffolding region of the web and sticky gumfooted capture lines had material properties similar to the major ampullate silk that orb weavers use as the framework for their orb webs. Major ampullate fibers obtained from anaesthetized Latrodectus spiders were similar, but exhibited increased stiffness and reduced extensibility. Novel continuous dynamic analysis of the silks revealed that the loss tangent (tanδ) increased rapidly during the first 2-3% of extension and reached a maximum near the yield point of fibers. The loss tangent then rapidly declined at an ever-decreasing rate until failure. We suggest that these data support molecular models for the mechanics of spider silk. We also demonstrate that the addition of sticky aggregate glue to the ends of the gumfooted lines modulates their mechanical performance - reducing stiffness and increasing extensibility. The storage modulus of viscid regions of the gumfooted lines was much lower than dry regions. This may be explained by disruption of hydrogen bonding within the amorphous regions of the fibers due to hydration from the glue.
Nitric oxide modulates peristaltic muscle activity associated with fluid circulation in the sea pansyRenilla koellikeri
Authors: Anctil Michel , Poulain Isabelle , Pelletier Claudine 
Published: May 2005

SUMMARYNitric oxide (NO) is a well-known regulator of vascular activities in vertebrates and it has also been implicated as a vasodilatatory agent in a cephalopod. In the sea pansy Renilla koellikeri, an octocorallian representative of the most basal animals with a nervous system, we investigated the role of NO in peristalsis, an activity that moves body fluids through the coelenteron (gastrovascular cavity) of the polyps across the colony. NO donors increased the amplitude of peristaltic contractions and increased tonic contractions in relaxed preparations, but caused a relaxation of basal tension in contracted preparations. The NO synthase (NOS) inhibitors L-NAME (N(ω)-nitro-L-arginine methyl ester) and 7-nitroindazole reduced the amplitude of peristaltic contractions and lowered basal tension. In contrast, aminoguanidine, a specific inhibitor of inducible NOS, increased the amplitude but reduced the rate of peristalsis. Zaprinast, a cGMP-specific phosphodiesterase inhibitor, decreased the amplitude of peristaltic contractions, a decrease that was amplified by dibutyryl cGMP. In contrast,the inhibitor of soluble guanylyl cyclase ODQ(1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one) enhanced peristalsis. Putative NOS-containing neurons, revealed by NADPH-diaphorase activity and citrulline immunohistochemistry, were observed in the basiectoderm at the base of the autozooid polyp tentacles and in a nerve-net around the oral disc. Their neurites ran up the tentacles and down to the polyp body wall, crossing from the ectoderm through the mesoglea and into the endoderm musculature where musculo-epithelial cells were also reactive. These data suggest that two distinct nitrergic pathways, one of which is mediated by cGMP, regulate peristalsis and muscle tone in the sea pansy and that these pathways may involve NOS-containing ectodermal neurons and musculo-epithelial cells.
The ecology of visual pigment tuning in an Australian marsupial: the honey possumTarsipes rostratus
Authors: Sumner Petroc , Arrese Catherine A. , Partridge Julian C. 
Published: May 2005

SUMMARYWhile most mammals have no more than two types of cone photoreceptor, four species of Australian marsupial have recently been shown to possess three types, and thus have the potential for trichromatic colour vision. Interestingly, the long-wave cones of the honey possum Tarsipes rostratus are tuned to longer wavelengths than those of the other species measured to date. We tested whether the honey possum's long-wave tuning is adaptive for visual tasks associated with its almost unique diet of nectar and pollen. We modelled three tasks: (1) detecting food-rich `target' flowers against their natural background of foliage or other vegetation; (2)discriminating target flowers from flowers of non-target species; (3)discerning the maturity of the most important target flowers. Initial comparisons of trichromacy vs dichromacy generally favoured the former, but interestingly dichromacy was no disadvantage in some cases. For tuning, we found that overall the honey possum's long-wave tuning is more adaptive than that of the other marsupial species. Nevertheless, the optimal tuning for tasks 1 and 2 would be at longer wavelengths still, implying that a different pressure or constraint operates against a further long-wave shift of the honey possum's L cone tuning. Our data show that a possible ecological pressure may be provided by the third task - the difficult and potentially critical discrimination of the maturity of the animal's major food supply, the flowers of Banksia attenuata.
Eco-friendly Synthesis of m-Tolunitrile by Heterogeneously Catalysed Liquid Phase Ammoxidation
Authors: Zhong Min , Liang Yong-guang , Liu Yuan , Ma Yu-long 
Published: May 2005

Abstract
The ammoxidation of m-xylene to m-tolunitrile over silica-supported Co–Mn–Ni catalyst was conducted for the first time in liquid phase without solvent in one-step procedure.
Highly Enantioselective Lipase-catalyzed Kinetic Resolution of 2-Silyloxy-1-propanol
Authors: Kawanami Yasuhiro , Itoh Kennji 
Published: May 2005

Abstract
The lipase-catalyzed kinetic resolutions of 2-benzyloxy- and 2-silyloxy-1-propanols have been investigated. Efficient modification of the substrate structure with the dimethylphenylsilyl protecting group and the use of lipase PS-D immobilized on diatomaceous earth were found to enhance the enantioselectivity and reactivity up to E = 240 at 0 °C.
Radiochemical separation of actinides from environmental samples for determination with DF-ICP-MS and alpha spectrometry
Authors: Ayranov Marin , Krähenbühl Urs , Sahli Hans , Röllin Stefan , Burger Mario 
Published: May 2005

Summary
The purpose of this study was to develop an optimised sample preparation method for the determination of Pu, Am, and Cm in environmental samples, soils, and sediments, and to compare the sensitivities of DF-ICP-MS, alpha spectrometry, and liquid scintillation alpha spectrometry. Borate fusion was used for sample material digestion. Two methods based on TOPO liquid–liquid extraction and combination of TEVA and TRU extraction chromatography showed highest yields of 92.7% for Pu, 86.8% for Am, and 87.6% for Cm. The detection limits were between 0.014–0.034 Bq/kg for 239Pu, 0.014–0.093 Bq/kg for 240Pu, and 0.011–1.20 Bq/kg for 241Am. Analytical results for 238Pu, 239Pu, 240Pu, 241Pu and 241Am and their isotope ratios in certified reference materials (IAEA-135 and IAEA-300) indicated very good accuracy of the methods proposed.
Microscale characterization of uranium(VI) silicate solids and associated neptunium(V)
Authors: Douglas Matthew , Clark Sue B. , Friese Judah I. , Arey Bruce W. , Buck Edgar C. , Hanson Brady D. , Utsunomiya Satoshi , Ewing Rodney C. 
Published: May 2005

Summary
The uranium(VI) silicate phases uranophane, Ca[(UO2)(SiO3OH)]2·5H2O, and sodium boltwoodite, Na[(UO2)(SiO3OH)]·1.5H2O, were synthesized in the presence of small, variable quantities (0.5–2.0 mol % relative to U) of pentavalent neptunium (Np(V), as NpO2
+), to investigate the nature of its association with these U(VI) solid phases. Solids were characterized by X-ray powder diffraction (XRD), gamma spectrometry (GS), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM) with electron energy-loss spectroscopy (EELS). Neptunium concentration was determined in the bulk solid phases by GS and was found to range from 780–15800 μg/g. In some cases, Np distributions between the aqueous and solid phases were monitored, and 78–97% of the initial Np was associated with the isolated solid. Characterization of individual crystallites by TEM/EELS suggests the Np is associated with the U(VI) phase. No discrete Np phases, such as Np oxides, were observed. Because the U(VI) silicates are believed to be important solubility-controlling solids on a geologic timescale, these results suggest that the partitioning of the minor actinides to these solids must be considered when assessing the performance of a waste repository for spent nuclear fuel.
Crystal structure of new uranyl oxalates (NH4)2[UO2(C2O4)2· H2O]·2H2O and (NH4)2-x(N2H5)x[(UO2)2(C2O4)3]·3H2O (x=0 and x=1). Comparison with other uranyl oxalates
Authors: Chapelet-Arab B. , Nowogrocki G. , Abraham F. , Grandjean S. 
Published: May 2005

SummaryTwo new ammonium uranyl oxalates (NH4)2-[UO2(C2O4)2H2O]·2H2O (1) and (NH4)2[(UO2)2(C2O4)3]· 3H2O (2) and one mixed ammonium hydrazinium uranyl oxalate (NH4)(N2H5)[(UO2)2(C2O4)3]·3H2O (3) have been prepared. The crystal structures of the three compounds have been determined by single-crystal X-ray diffraction. The crystal structures were solved by the Patterson method and Fourier difference techniques, and refined by a least square method on the basis of F2for all unique reflections. Crystallographic data: 1, hexagonal, space group P6122,a=8.143(2) Å,c=36.179(18) Å,Z=6,R1= 0.0268 for 105 parameters with 1223 reflections withI≥ 2σ(I); 2, monoclinic, space groupP21/n,a=8.705(3) Å,b= 19.454(6) Å,c=5.5105(18) Å, β=101.741(5)°,Z=2,R1= 0.0314 for 139 parameters with 2059 reflections withI≥ 2σ(I); 3, monoclinic, space groupP21/n,a=8.958(3) Å,b=19.601(7) Å,c= 11.007(4) Å, β=112.928(5)°,Z=4,R1=0.0363 for 131 parameters with 3346 reflections withI≥ 2σ(I). The crystal structure of 1 contains [UO2(C2O4)2· H2O]2−anions, NH4+cations and water molecules. In the anion, the linear uranyl group is coordinated by two bidentate oxalate anions and one water molecule giving a pentagonal bipyramidal environment for the uranium atom. The structures of 2 and 3 consist of two-dimensional networks built from uranyl and oxalate ions forming hexagonal rings. The oxalate ions are tetradentate, each bridging two uranyl ions which are coordinated by three oxalate groups to give distorted hexagonal bipyramidal environments for the uranium atoms. In 3, the ammonium and hydrazinium ions are ordered in successive layers. The various possible coordinations for the uranyl cation and the great versatility of the oxalate anion are magnificently illustrated in the monovalent ion-uranyl double oxalates series and other structures are expected by the diversification of the synthesis methods and experimental conditions.
Extraction of U(VI) with unsymmetrical N-methyl-N-decylalkylamide in toluene
Authors: Cui Yu , Sun Guoxin , Zhang Zhenwei , Li Yexin , Sun Sixiu 
Published: May 2005

Summary
A number of structurally related new unsymmetrical monoamides with different substituting groups, N-methyl-N-decyloctylamide (MDOA), N-methyl-N-decyldecanamide (MDDA), and N-methyl-N-decyldodecanamide (MDDOA), were synthesized. The extraction of U(VI) from nitric acid medium by the synthesized monoamides diluted with toluene was investigated. The effect of nitric acid concentration, sodium nitrate concentration, extractant concentration and temperature on the distribution ratio was studied. The stoichiometry of the main extracted species confirms to UO2(NO3)2·2A (A, amidic extractant). The values of the thermodynamic parameters were determined and the extraction reactions were found exothermic. The IR spectral study was also made of the extracted species.
Speciation of Tc(IV) in chloride solutions by capillary electrophoresis
Authors: Liu Xiaolan , Poineau Frédéric , Fattahi Massoud , Grambow Bernd , Vichot L. 
Published: May 2005

Summary
A method for speciation of Tc(IV) species (TcCl6
2− and TcCl5(H2O)−) in chloride solutions, using capillary electrophoresis (CE) technique was developed. The proposed method has overcome the difficulties of unstable oxidation states analysis by shortening their travel time in the capillary. TcCl6
2− and TcCl5(H2O)− were thus separated without being hydrolyzed and polymerized, and their UV/Vis spectra were recorded. With a 1 M HCl/NaCl buffer solution (pH=1), the electrophoretic mobilities were determined as 5.47×10−4 cm2/Vs for TcCl6
2− and 2.13×10−4 cm2/Vs for TcCl5(H2O)− at 25 °C. The total analysis time for one run is 12 minutes.
Seasonality of growth response to GH therapy in prepubertal children with idiopathic growth hormone deficiency
Authors: Land C , Blum W F , Stabrey A , Schoenau E 
Published: May 2005

Objective: Longitudinal growth of children exhibits seasonal variation. In both healthy children and in children with growth hormone (GH) deficiency (GHD) receiving GH therapy, growth rate is maximal during spring and summer. In the present study, we analyzed the growth response to GH therapy in children with GHD as a function of the season when therapy was started.
Subjects and methods: Anthropometric measurements and biochemical analyses of GH secretion status and bone formation were longitudinally assessed in a cohort of 52 prepubertal children with GHD (14 girls, mean age 7.6 years) who were treated with a fixed dose of GH (0.025 mg/kg/day).
Results: Auxological assessments over the 2-year observation period revealed a significantly better growth response to GH therapy in children who started therapy between the spring and summer (group 1) compared with children who started in the autumn or winter (group 2). The difference was largest in the initial 3-month treatment period (35%; P < 0.01). The initial better gain in height of group 1 was sustained during the study period. Baseline peak GH levels during stimulation tests and insuin-like growth factor-I levels did not differ between the two groups. However, group 1 had significantly higher bone resorption and formation markers, either at the start or shortly after initiation of GH treatment. This suggests that children with GHD have higher bone turnover during spring and early summer, irrespective of GH therapy.
Conclusions: In summary, this study suggests that the season of GH initiation is a determinant of the initial growth response to GH replacement in prepubertal children with GHD.
Thyrotrophin-releasing hormone receptor 1 and prothyrotrophin-releasing hormone mRNA expression in the central nervous system are regulated by suckling in lactating rats
Authors: Fjeldheim Åse-Karine , Høvring Per Ivar , Løseth Ole-Petter , Johansen Per Wiik , Glover Joel C , Matre Vilborg , Olstad Ole Kristoffer , Reppe Sjur , Gordeladze Jan O , Walaas S Ivar , Gautvik Kaare M 
Published: May 2005

Background: The accepted function of the hypothalamic peptide, thyrotrophin-releasing hormone (TRH), is to initiate release of thyrotrophin (TSH) from the pituitary. A physiological role for TRH in lactating rats has not yet been established.Methods: Tissues were prepared from random-cycling and lactating rats and analysed using Northern blot, real time RT-PCR and quantitativein situhybridisation.Results: This study demonstrates that TRH receptor 1 (TRHR1) mRNA expression is up-regulated in the pituitary and in discrete nuclei of the hypothalamus in lactating rats, while proTRH mRNA expression levels are increased only in the hypothalamus. The results were corroborated by quantitativein situanalysis of proTRH and TRHR1. Bromocriptine, which reduced prolactin (PRL) concentrations in plasma of lactating and nursing rats, also counteracted the suckling-induced increase in TRHR1 mRNA expression in the hypothalamus, but had an opposite effect in the pituitary. These changes were confined to the hypothalamus and the amygdala in the brain.Conclusions: The present study shows that the mechanisms of suckling-induced lactation involve region-specific regulation of TRHR1 and proTRH mRNAs in the central nervous system notably at the hypothalamic level. The results demonstrate that continued suckling is critical to maintain plasma prolactin (PRL) levels as well as proTRH and TRHR1 mRNA expression in the hypothalamus. Increased plasma PRL levels may have a positive modulatory role on the proTRH/TRHR1 system during suckling.
Effect of long-term continuous methimazole treatment of hyperthyroidism: comparison with radioiodine
Authors: Azizi F , Ataie L , Hedayati M , Mehrabi Y , Sheikholeslami F 
Published: May 2005

Objective: To investigate the long-term effects of continuous methimazole (MMI) therapy.
Design and methods: Five hundred and four patients over 40 years of age with diffuse toxic goiter were treated with MMI for 18 months. Within one year after discontinuation of MMI, hyperthyroidism recurred in 104 patients. They were randomized into 2 groups for continuous antithyroid and radioiodine treatment. Numbers of occurrences of thyroid dysfunction and total costs of management were assessed during 10 years of follow-up. At the end of the study, 26 patients were still on continuous MMI (group 1), and of 41 radioiodine-treated patients (group 2), 16 were euthyroid and 25 became hypothyroid. Serum thyroid and lipid profiles, bone mineral density, and echocardiography data were obtained.
Results: There was no significant difference in age, sex, duration of symptoms and thyroid function between the two groups. No serious complications occurred in any of the patients. The cost of treatment was lower in group 1 than in group 2. At the end of 10 years, goiter rate was greater and antithyroperoxidase antibody concentration was higher in group 1 than in group 2. Serum cholesterol and low density lipoprotein-cholesterol concentrations were increased in group 2 as compared with group 1; relative risks were 1.8 (1.12–2.95, P < 0.02) and 1.6 (1.09–2.34, P < 0.02) respectively. Bone mineral density and echocardiographic measurements were not different between the two groups.
Conclusion: Long-term continuous treatment of hyperthyroidism with MMI is safe. The complications and the expense of the treatment do not exceed those of radioactive iodine therapy.
Defect of a subpopulation of natural killer immune cells in Graves’ disease and Hashimoto’s thyroiditis: normalizing effect of dehydroepiandrosterone sulfate
Authors: Solerte Sebastiano Bruno , Precerutti Sara , Gazzaruso Carmine , Locatelli Eleonora , Zamboni Mauro , Schifino Nicola , Bonacasa Roberto , Rondanelli Mariangela , Taccani Davide , Ferrari Ettore , Fioravanti Marisa 
Published: May 2005

Background: The study of the natural killer (NK) immune compartment could provide important findings to help in the understanding of some of the pathogenetic mechanisms related to autoimmune thyroid diseases (Graves’ disease (GD) and Hashimoto’s thyroiditis (HT)). Within this context, it was suggested that alterations in NK cell cytotoxicity (NKCC) and NK production of cytokines might occur in subjects with GD and HT, whereas the normalization of NK functions could potentially contribute to the prevention of the onset or the progression of both diseases.Objective: Due to the hypothesis of alterations in NK in autoimmune thyroid diseases, we were interested to evaluate NKCC in GD and HT patients and to modulate NK function and secretory activity with cytokines and dehydroepiandrosterone sulfate (DHEAS) in an attempt to normalize NK cell defect.Design: We studied 13 patients with recent onset Graves’ disease, 11 patients with Hashimoto’s thyroiditis at first diagnosis and 15 age-matched healthy subjects.Methods: NK cells were concentrated at a density of 7.75 × 106cells/ml by negative immunomagnetic cell separation and validated by FACScan as CD16 + /CD56 + cells. NK cells were incubated with interleukin-2 (IL-2) and interferon-β (IFN-β) and co-incubated with DHEAS at different molar concentrations for measuring NKCC and the secretory pattern of tumor necrosis factor-α (TNF-α) from NK cells.Results: Lower spontaneous, IL-2- and IFN-β-modulated NKCC was demonstrated in GD and HT patients compared with healthy subjects (P< 0.001). A decrease in spontaneous and IL-2-modulated TNF-α release from NK cells was also found in both groups of patients (P< 0.001). The co-incubation of NK cells with IL-2/IFN-β + DHEAS at different molar concentrations (from 10−8to 10−5M/ml/NK cells) promptly normalized NKCC and TNF-α secretion in GD and HT patients.Conclusions: A functional defect of a subpopulation of NK immune cells, involving both NKCC and the secretory activity, was demonstrated in newly-diagnosed GD and HT patients. This defect can be reversed by a dose-dependent treatment with DHEAS. The impairment of NK cell activity in autoimmune thyroid diseases could potentially determine a critical expansion of T/B-cell immune compartments leading to the generation of autoantibodies and to the pathogenesis of thyroid autoimmunity.
Health status in patients with sub-clinical hypothyroidism
Authors: Razvi Salman , Ingoe Lorna E , McMillan Carolyn V , Weaver Jolanta U 
Published: May 2005

Objective: Sub-clinical hypothyroidism (SCH) is a common disorder. People with this condition may have symptoms which could affect their perception of health. Therefore, the perceived health status of people with SCH was assessed and compared with population-matched norms.
Design: A prospective cross-sectional survey.
Methods: Seventy-one adults with SCH, age range 18–64 years were studied. Perceived health status was measured by the Short Form-36 (SF-36) version 2 questionaire, which has been validated in a UK population setting. The SF-36 has eight scales measuring physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional and mental health. Their SF-36 scores were compared with UK normative data after matching for age and sex and are reported as z-scores.
Results: Scores of all eight SF-36 scales were significantly lower in people with SCH compared with the normative population. A negative score (compared with zero of the normative population) indicates worse health status. The most significantly impaired aspects of health status were vitality and role limitations due to physical problems (role physical scale) with z-scores (95% confidence intervals) of −1.01 (−0.74 to −1.29) and −0.73 (−0.43 to −1.04) respectively. Thyroid autoimmunity did not influence the results.
Conclusion: Perceived health status is significantly impaired in people with SCH when compared with UK normative population scores. This needs to be taken into consideration by clinicians when managing patients with this disease.