bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ontogeny of osmoregulatory structures and functions in the green crabCarcinus maenas(Crustacea, Decapoda)
Authors: Cieluch Ude , Anger Klaus , Aujoulat Fabien , Buchholz Friedrich , Charmantier-Daures Mireille , Charmantie Guy 
Published: December 2003

SUMMARYThe ontogeny of osmoregulation, the development of branchial transporting epithelia and the expression of the enzyme Na+/K+-ATPase were studied in Carcinus maenas (L.) obtained from the North Sea,Germany. Laboratory-reared zoea larvae, megalopae and young crabs were exposed to a wide range of salinities, and hemolymph osmolality was measured after 24 h exposure time (72 h in juveniles). Zoea I larvae slightly hyper-regulated in dilute media (10.2‰ and 17.0‰) and osmoconformed at&gt;17‰. All later zoeal stages (II-IV) osmoconformed in salinities from 10.2‰ to 44.3‰. The megalopa hyper-regulated at salinities from 10.2 to 25.5‰. Young crabs hyperregulated at salinities from 5.3‰ to 25.5‰, showing an increase in their osmoregulatory capacity. The development of transporting epithelia and the expression of Na+/K+-ATPase were investigated by means of transmission electron microscopy and immunofluorescence microscopy. In the zoea IV, only a very light fluorescence staining was observed in gill buds. Epithelial cells were rather undifferentiated, without showing any features of ionocytes. Gills were present in the megalopa, where Na+/K+-ATPase was located in basal filaments of the posterior gills. In crab I juveniles and adults, Na+/K+-ATPase was noted in the three most posterior pairs of gills, but lacking in anterior gills. Ionocytes could first be recognized in filaments of megalopal posterior gills, persisting through subsequent stages at the same location. Thus, the development of the gills and the expression of Na+/K+-ATPase are closely correlated with the ontogeny of osmoregulatory abilities. The morphological two-step metamorphosis of C. maenas can also be regarded as an osmo-physiological metamorphosis, (i) from the osmoconforming zoeal stages to the weakly regulating megalopa, and (ii) to the effectively hyper-regulating juvenile and adult crabs.
Cold-acclimation inPeromyscus: temporal effects and individual variation in maximum metabolism and ventilatory traits
Authors: Rezende Enrico L. , Chappell Mark A. , Hammond Kimberly A. 
Published: December 2003

SUMMARYThermal acclimation in small endotherms provides an excellent model for the study of physiological plasticity, as energy requirements can be easily manipulated and the results are relevant for natural conditions. Nevertheless,how physiology changes throughout acclimation, and how individuals vary in their response to acclimation, remain poorly understood. Here we describe a high temporal-resolution study of cold acclimation in the deer mouse Peromyscus maniculatus. The experimental design was based on repeated measures at short intervals throughout cold acclimation, with controls(maintained at constant temperature) for measurement artifacts. We monitored body mass, maximum metabolic rate in cold exposure and ventilatory traits(respiratory frequency, tidal and minute volume and oxygen extraction) for 3 weeks at 23°C. Then, half of the individuals were held for 7 weeks at 5°C. Body mass was differently affected by cold acclimation depending on sex. Maximal metabolism(V̇O2max)increased significantly during the first week of cold acclimation, `overshot'after 5 weeks and dropped to a plateau about 34% above control values at week 7. Similarly, ventilatory traits increased during cold acclimation, though responses were different in their kinetics and magnitude. Body mass, maximum metabolism, and most ventilatory traits were repeatable after 7 weeks in control and cold-acclimated animals. However, repeatability tended to be lower in the cold-acclimated group, especially while animals were still acclimating. Our results show that acclimation effects may be under- and/or overestimated,depending on when trials are performed, and that different traits respond differently, and at different rates, to acclimation. Hence, future studies should be designed to ensure that animals have attained steady-state values in acclimation experiments.
Locomotion of lizards on inclines and perches: hindlimb kinematics of an arboreal specialist and a terrestrial generalist
Authors: Higham Timothy E. , Jayne Bruce C. 
Published: December 2003

SUMMARYArboreal animals, especially lizards, often traverse three-dimensional networks of narrow perches with variable and steep inclines, but the effects of both incline and narrow surfaces on the locomotor movement and function of limbs are poorly understood. Thus, we quantified the three-dimensional hindlimb kinematics of a specialized arboreal lizard, Chamaeleo calyptratus, moving horizontally, and up and down a 30° incline on a narrow (2.4 cm) perch and a flat surface. We compared the flat-surface data of C. calyptratus with those of an anatomically generalized terrestrial lizard, Dipsosaurus dorsalis. Inclines had significant main effects for relatively few kinematic variables of C. calyptratus (11%)compared to D. dorsalis (73%). For C. calyptratus, the main effects of locomotor surface were nearly three times more widespread than those of incline. The foot of C. calyptratus was markedly anterior to the hip at footfall, primarily as a result of an unusually extended knee for a lizard. A large amount of knee flexion during early stance may be used by C. calyptratus to actively pull the body forward in a manner not found in D. dorsalis. Unexpectedly, the pelvic rotation of C. calyptratus greatly exceeded that of D. dorsalis and, unlike D. dorsalis, was not affected by incline. The more medial location of the foot of C. calyptratus on the narrow perch during stance was primarily a result of knee flexion rather than femur depression. Unlike previous qualitative descriptions of chameleons, our data for the hindlimb posture of C. calyptratus during stance indicate that the limb was not particularly erect.
Dynamics of leg muscle function in tammar wallabies (M. eugenii)during levelversusincline hopping
Authors: Biewener A. A. , McGowan C. , Card G. M. , Baudinette R. V. 
Published: December 2003

SUMMARYThe goal of our study was to examine whether the in vivoforce-length behavior, work and elastic energy savings of distal muscle-tendon units in the legs of tammar wallabies (Macropus eugenii) change during level versus incline hopping. To address this question, we obtained measurements of muscle activation (via electromyography),fascicle strain (via sonomicrometry) and muscle-tendon force(via tendon buckles) from the lateral gastrocnemius (LG) and plantaris (PL) muscles of tammar wallabies trained to hop on a level and an inclined (10°, 17.4% grade) treadmill at two speeds (3.3 m s-1and 4.2 m s-1). Similar patterns of muscle activation, force and fascicle strain were observed under both level and incline conditions. This also corresponded to similar patterns of limb timing and movement (duty factor, limb contact time and hopping frequency). During both level and incline hopping, the LG and PL exhibited patterns of fascicle stretch and shortening that yielded low levels of net fascicle strain [LG: level,-1.0±4.6% (mean ± s.e.m.) vs incline,0.6±4.5%; PL: level, 0.1±1.0% vs incline,0.4±1.6%] and muscle work (LG: level, -8.4±8.4 J kg-1muscle vs incline, -6.8±7.5 J kg-1 muscle; PL:level, -2.0±0.6 J kg-1 muscle vs incline,-1.4±0.7 J kg-1 muscle). Consequently, neither muscle significantly altered its contractile dynamics to do more work during incline hopping. Whereas electromyographic (EMG) phase, duration and intensity did not differ for the LG, the PL exhibited shorter but more intense periods of activation, together with reduced EMG phase (P&lt;0.01), during incline versus level hopping. Our results indicate that design for spring-like tendon energy savings and economical muscle force generation is key for these two distal muscle-tendon units of the tammar wallaby, and the need to accommodate changes in work associated with level versusincline locomotion is achieved by more proximal muscles of the limb.
Prognostic Value of Combination of Cardiac Troponin T and B-Type Natriuretic Peptide after Initiation of Treatment in Patients with Chronic Heart Failure
Authors: Ishii Junnichi , Cui Wei , Kitagawa Fumihiko , Kuno Takahiro , Nakamura Yuu , Naruse Hiroyuki , Mori Yoshihisa , Ishikawa Takashi , Nagamura Youichi , Kondo Takeshi , Oshima Hisaji , Nomura Masanori , Ezaki Kouji , Hishida Hitoshi 
Published: December 2003

AbstractBackground: Recent studies have suggested that cardiac troponin T (cTnT) and troponin I may detect ongoing myocardial damage involved in the progression of chronic heart failure (CHF). This study was prospectively designed to examine whether the combination of cTnT, a marker for ongoing myocardial damage, and B-type natriuretic peptide (BNP), a marker for left ventricular overload, would effectively stratify patients with CHF after initiation of treatment.Methods: We measured serum cTnT, plasma BNP, and left ventricular ejection fraction (LVEF) on admission for worsening CHF [New York Heart Association (NYHA) functional class III to IV] and 2 months after initiation of treatment to stabilize CHF (n = 100; mean age, 68 years).Results: Mean (SD) concentrations of cTnT [0.023 (0.066) vs 0.063 (0.20) μg/L] and BNP [249 (276) vs 753 (598) ng/L], percentage increased cTnT (&gt;0.01 μg/L; 35% vs 60%), NYHA functional class [2.5 (0.6) vs 3.5 (5)], and LVEF [43 (13)% vs 36 (12)%] were significantly (P &lt;0.01) improved 2 months after treatment compared with admission. During a mean follow-up of 391 days, there were 44 cardiac events, including 12 cardiac deaths and 32 readmissions for worsening CHF. On a stepwise Cox regression analysis, increased cTnT and BNP were independent predictors of cardiac events (P &lt;0.001). cTnT &gt;0.01 μg/L and/or BNP &gt;160 ng/L 2 months after initiation of treatment were associated with increased cardiac mortality and morbidity rates.Conclusion: The combination of cTnT and BNP measurements after initiation of treatment may be highly effective for risk stratification in patients with CHF.
Amino-Terminal Form of Parathyroid Hormone (PTH) with Immunologic Similarities to hPTH(1–84) Is Overproduced in Primary and Secondary Hyperparathyroidism
Authors: D’Amour Pierre , Brossard Jean-Hugues , Rousseau Louise , Roy Louise , Gao Ping , Cantor Tom 
Published: December 2003

AbstractBackground: To separate non-(1–84)parathyroid hormone [non-(1–84)PTH] from PTH(1–84), we developed new HPLC gradients and observed that the peak coeluting with hPTH(1–84) could be separated into two entities recognized by a cyclase-activating PTH (CA-PTH) assay that reacts with the first four amino acids of the PTH structure.Methods: Sera from six healthy individuals and five patients with primary hyperparathyroidism, and eight pools of sera from patients in renal failure were fractionated by HPLC. A total (T)-PTH assay reacting with the (15–20) region, the CA-PTH assay, and a COOH-terminal (C)-PTH assay with a (65–84) structure requirement were used to measure basal and fractionated PTH values.Results: T-PTH was higher than CA-PTH in all healthy controls [mean (SD), 3.13 (0.37) vs 2.29 (0.33) pmol/L; P &lt;0.01] and in renal failure patients [47 (35.1) vs 33.4 (26.1) pmol/L; P &lt;0.01]. By contrast, CA-PTH concentrations were similar to or higher than T-PTH in three of five patients with primary hyperparathyroidism [25.7 (26.1) vs 23.1 (24.2) pmol/L; not significant]. The CA-PTH assay reacted with the hPTH(1–84) peak and with a minor peak different from the non-(1–84) peak recognized by the T-PTH assay. This minor peak was not recognized by the T-PTH assay. It represented 8 (2)% of CA-PTH in controls, 25 (23)% in patients with primary hyperparathyroidism, and 22 (7)% in renal failure patients, assuming equimolar reactivity to hPTH(1–84) in the CA-PTH assay. It was not oxidized hPTH(1–84), which migrated differently on HPLC and reacted similarly in the CA and T-PTH assays.Conclusions: This new molecular form of PTH has structural integrity of the (1–4) region but presumably is modified in the region (15–20), which is usually recognized by the T-PTH assay. Its clinical implications remain to be defined.
Simultaneous Determination of Tocotrienols, Tocopherols, Retinol, and Major Carotenoids in Human Plasma
Authors: Lee Bee-Lan , New Ai-Li , Ong Choon-Nam 
Published: December 2003

Abstract
Background: Epidemiologic evidence suggests that the concentrations of antioxidant vitamins in human plasma may play an important role in numerous chronic diseases, such as cancer and cardiovascular disease. However, methods for simultaneous measurement of these antioxidants are scarce. We developed and validated a new HPLC method for simultaneous determination of these vitamers in human plasma that uses a novel column-switching approach.
Methods: The new method uses liquid–liquid extraction and isocratic separation with two monomeric C18 columns maintained at 35 and 4 °C coupled with ultraviolet–visible and fluorometric detection. This method could separate 14 vitamers and 3 internal standards within 27 min. No additional modifier was required; the mobile phase was acetonitrile–methanol (65:35 by volume), and the flow rate was 1 mL/min.
Results: For photodiode array detection, the detection limits (signal-to-noise ratio &gt;3) were 0.02 mg/L for β-carotene, lutein, zeaxanthin, and canthaxanthin; 0.01 mg/L for all-trans-retinol, β-cryptoxanthin, α-carotene, and lycopene; and 0.1 mg/L for all tocopherols and tocotrienols. The detection limit was at least 25-fold lower (0.004 mg/L) when fluorometry was used for measurement of δ-, γ-, and α-tocotrienol and δ-tocopherol compared with ultraviolet detection. The recovery and imprecision of the assay were generally &gt;90% and &lt;10%, respectively.
Conclusions: This new method separates a wide range of fat-soluble antioxidant vitamins in human plasma, including six carotenoids, three isoforms of tocotrienols and tocopherols (δ-, γ-, and α-), and all-trans-retinol. The overall findings suggest that our method is faster, more sensitive, and more comprehensive than existing methods.
Identification of New Mutations of the HFE, Hepcidin, and Transferrin Receptor 2 Genes by Denaturing HPLC Analysis of Individuals with Biochemical Indications of Iron Overload
Authors: Biasiotto Giorgio , Belloli Silvana , Ruggeri Giuseppina , Zanella Isabella , Gerardi Gianmario , Corrado Marcella , Gobbi Elena , Albertini Alberto , Arosio Paolo 
Published: December 2003

Abstract
Background: Hereditary hemochromatosis is a recessive disorder characterized by iron accumulation in parenchymal cells, followed by organ damage and failure. The disorder is mainly attributable to the C282Y and H63D mutations in the HFE gene, but additional mutations in the HFE, transferrin receptor 2 (TfR2), and hepcidin genes have been reported. The copresence of mutations in different genes may explain the phenotypic heterogeneity of the disorder and its variable penetrance.
Methods: We used denaturing HPLC (DHPLC) for rapid DNA scanning of the HFE (exons 2, 3, and 4), hepcidin, and TfR2 (exons 2, 4 and 6) genes in a cohort of 657 individuals with altered indicators of iron status.
Results: DHPLC identification of C282Y and H63D HFE alleles was in perfect agreement with the restriction endonuclease assay. Fourteen DNA samples were heterozygous for the HFE S65C mutation. In addition, we found novel mutations: two in HFE (R66C in exon 2 and R224G in exon 4), one in the hepcidin gene (G71D), and one in TfR2 (V22I), plus several intronic or silent substitutions. Six of the seven individuals with hepcidin or TfR2 coding mutations carried also HFE C282Y or S65C mutations.
Conclusion: DHPLC is an efficient method for mutational screening for the genes involved in hereditary hemochromatosis and for the study of their copresence.
Effects of LDL, Cholesterol, and Their Oxidized Forms on the Precipitation Kinetics of Calcium Phosphates
Authors: Wang He-Ping , Feng Xiao-Jing , Gou Bao-Di , Zhang Tian-Lan , Xu Shan-Jin , Wang Kui 
Published: December 2003

AbstractBackground: LDL, cholesterol, and their oxidized forms are known cardiovascular risk factors and are often found in atherosclerotic lesions of various stages. Little is known, however, about whether they are directly involved in the formation of calcium phosphate compounds.Methods: We used the pH-stat technique to follow the kinetics of calcium phosphate precipitation at pH 7.4, 37 °C, and ionic strength 0.150 mol/L, in the presence or absence of LDL, oxidized LDL, cholesterol, cholestane-3β,5α,6β-triol, and cholesteryl linoleate. The precipitates were characterized by x-ray diffraction, scanning and transmission electronic microscopy coupled with energy-dispersion x-ray analysis, and inductively coupled plasma atomic emission spectroscopy.Results: Under the experimental conditions, LDL (14.8 and 43.1 mg/L protein) had no significant effect on the precipitation kinetics. Oxidized LDL (14.8 and 43.1 mg/L protein) prolonged the nucleation phase and diminished the amount of total precipitate, and both the extent of oxidation and the concentration of the protein affected the kinetics. Cholesterol microcrystals (71.4 and 143 mg/L) made the nucleation phase shorter (300 min vs 390 min for the control), and the precipitated particles had an organic core and a shell composed of calcium phosphates. l-α-Phosphatidylcholine vesicles (143 mg/L), cholesterol (71.4 mg/L)/phospholipid (143 mg/L) mixed vesicles, cholesteryl linoleate (143 mg/L), and cholestane-3β,5α,6β-triol (71.4 mg/L) prolonged the nucleation phase.Conclusions: LDL is not involved directly in the precipitation of calcium phosphates. Oxidized LDL inhibits both nucleation and crystal growth, possibly by attracting calcium ions in the solution and thus reducing supersaturation. Cholesterol microcrystals serve as seeds for the precipitation of hydroxyapatite, whereas l-α-phosphatidylcholine, cholesteryl linoleate, and cholestane-3β,5α,6β-triol exhibit inhibitive effects on the nucleation of calcium phosphates.
Domains and Rafts in Lipid Membranes
Authors: Binder Wolfgang H. , Barragan Veronique , Menger Fredric M. 
Published: December 2003

Abstract“It takes a membrane to make sense out of disorder in biology. You have to be able to catch energy and hold it, storing precisely the needed amount and releasing it in measured shares”. So wrote Lewis Thomas in The Lives of Cells. Domains and rafts are shown in the present Review to play an important role in this amazing behavior of lipid membranes. Topics touched upon include the experimental detection of domains, their composition, domain induction, properties of rafts (a special form of domain), and the relationship of rafts to human diseases. Lipids, polymers, and proteins can contribute to this type of micro‐ and nanostructuring within membranes, thus imposing a new structural hierarchy on top of the classical bilayer membrane. The purpose of this Review is to develop an appreciation for the multiple organizational levels in self‐assembling systems.
Geoelectric prospection of a city wall by multi‐electrode resistivity image survey at the prehistoric site of Asea (southern Greece)
Authors: Dogan M. , Papamarinopoulos S. 
Published: December 2003

AbstractElectric resistivity imaging survey was carried out at the archaeological site of Asea as part of a programme of cooperative research between the Swedish Institute at Athens and the University of Patras. This paper presents the geophysical results of the first field season 2001. It is intended to explore the buried extension of the city wall in order to contribute to progressive research on the responses of the resistivity method to intact subsurface archaeological features (wall, void, tunnel, etc.). The survey was performed by means of a Geopulse imager system with 25 electrodes and an electrode spacing of 1 m. The Wenner–Schlumberger array was selected for measurements. The city wall was imaged in both north and south directions. The results indicate that the resistivity method can provide a clear pseudo‐image of medium to large size walls with high accuracy on archaeological sites. Copyright © 2003 John Wiley & Sons, Ltd.
Geophysical surveys of Bury Walls hill fort, Shropshire
Authors: Murdie Ruth E. , White Roger H. , Barratt Glynn , Gaffney Vince , Goulty Neil R. 
Published: December 2003

AbstractThe hill fort of Bury Walls in Shropshire has been surveyed extensively by topographical and geophysical methods with the aims of recovering evidence for occupation, characterising the use of the hill fort and clarifying the chronological development of the site. Topographic surveys delineated the current extent of the fort and its massive fortifications. Resistance surveys showed several interesting features inside the fort, including extensive use of the geology to make flattened ledges in an otherwise quite uneven fort interior, a possible cross dyke, interior roads and traces of possible dwellings. Magnetic gradient surveys again showed clearly the possible cross dyke. Additional geophysical surveys attempted to define the depths of these features found in the resistance and magnetic gradient maps. This study, although not fully answering the original aims, provides a useful basis for future excavation. Copyright © 2003 John Wiley & Sons, Ltd.
A method to solve the multilayer non‐continuity problem for heat and moisture transfer in building structures
Authors: Su X. , Ang H. 
Published: December 2003

AbstractIn this paper a finite‐difference method is proposed for the first time for the solution of coupled heat and moisture transfer problems of transient nature in 1‐D multilayer building elements. Transient boundary conditions are specified for both heat and moisture transfer at external surfaces, while constant values are assumed for material properties of each layer of the structure. The calculations for a typical three layers wall are conducted to obtain the dynamic distributions of the relative humidity at the interfaces of every layer during 24 h by use of the mentioned method, and the results agree with the transfer function method in (ASHRAE Trans. 1999; 105(2) : 954–961). The method can be extended to 2‐D and 3‐D coupled heat and moisture transfer problems. Copyright © 2003 John Wiley Sons, Ltd.
P‐wave and S‐wave decomposition in boundary integral equation for plane elastodynamic problems
Authors: Perrey‐Debain Emmanuel , Trevelyan Jon , Bettess Peter 
Published: December 2003

AbstractThe method of plane wave basis functions, a subset of the method of Partition of Unity, has previously been applied successfully to finite element and boundary element models for the Helmholtz equation. In this paper we describe the extension of the method to problems of scattering of elastic waves. This problem is more complicated for two reasons. First, the governing equation is now a vector equation and second multiple wave speeds are present, for any given frequency. The formulation has therefore a number of novel features. A full development of the necessary theory is given. Results are presented for some classical problems in the scattering of elastic waves. They demonstrate the same features as those previously obtained for the Helmholtz equation, namely that for a given level of error far fewer degrees of freedom are required in the system matrix. The use of the plane wave basis promises to yield a considerable increase in efficiency over conventional boundary element formulations in elastodynamics. Copyright © 2003 John Wiley & Sons, Ltd.