bluuebunny/crossref_metadata_2025_split huggingface dataset:
New insights into force depression in skeletal muscle
Authors: Joumaa Venus , MacIntosh Brian R. , Herzog Walter 
Published: May 2012

SUMMARYForce depression observed following active shortening is not well understood. Previous research suggested that force depression might be associated with a stress-induced inhibition of cross-bridges in the newly formed overlap zone following shortening. Our aim was to investigate this theory in skinned fibres and determine whether there was an inhibition of the attachment of cross-bridges or a decrease in the force produced per cross-bridge. The stress-induced inhibition of cross-bridge theory gives testable predictions, including: (1) skinned fibres should show proportional force and stiffness depression, (2) force after shortening should not be lower than force before shortening, (3) stiffness following shortening should not be lower than stiffness before shortening and (4) force depression should decrease when the stress during shortening is decreased. In agreement with these predictions, force and stiffness depression were approximately proportional, and force depression decreased with decreasing stress during shortening. However, in contrast to the predictions of the stress-induced inhibition of cross-bridge theory, force after shortening from sarcomere lengths of 2.8 and 3.0 μm to a sarcomere length of 2.4 μm was smaller than force before shortening, and this was not accompanied by a corresponding decrease in stiffness. We conclude that the stress-induced inhibition of cross-bridge theory, as proposed previously, cannot be the only mechanism for force depression, but that there is an additional, stress-induced inhibition of cross-bridges in the old overlap zone. Furthermore, both mechanisms, inhibition of cross-bridge attachment and reduction of force produced per cross-bridge, contribute to force depression. Inhibition and/or reduction of force depend(s) on the amount of stress imposed on actin during the shortening phase.
Mitochondrial function in sparrow pectoralis muscle
Authors: Kuzmiak Sarah , Glancy Brian , Sweazea Karen L. , Willis Wayne T. 
Published: May 2012

SUMMARY
Flying birds couple a high daily energy turnover with double-digit millimolar blood glucose concentrations and insulin resistance. Unlike mammalian muscle, flight muscle predominantly relies on lipid oxidation during locomotion at high fractions of aerobic capacity, and birds outlive mammals of similar body mass by a factor of three or more. Despite these intriguing functional differences, few data are available comparing fuel oxidation and free radical production in avian and mammalian skeletal muscle mitochondria. Thus we isolated mitochondria from English sparrow pectoralis and rat mixed hindlimb muscles. Maximal O2 consumption and net H2O2 release were measured in the presence of several oxidative substrate combinations. Additionally, NAD- and FAD-linked electron transport chain (ETC) capacity was examined in sonicated mitochondria. Sparrow mitochondria oxidized palmitoyl-l-carnitine 1.9-fold faster than rat mitochondria and could not oxidize glycerol-3-phosphate, while both species oxidized pyruvate, glutamate and malate–aspartate shuttle substrates at similar rates. Net H2O2 release was not significantly different between species and was highest when glycolytic substrates were oxidized. Sonicated sparrow mitochondria oxidized NADH and succinate over 1.8 times faster than rat mitochondria. The high ETC catalytic potential relative to matrix substrate dehydrogenases in sparrow mitochondria suggests a lower matrix redox potential is necessary to drive a given O2 consumption rate. This may contribute to preferential reliance on lipid oxidation, which may result in lower in vivo reactive oxygen species production in birds compared with mammals.
Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation
Authors: Lin David C. , Hershey John D. , Mattoon John S. , Robbins Charles T. 
Published: May 2012

SUMMARY
Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and summer-active brown bears (Ursus arctos). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT) musculotendon masses on the denervated side decreased after 11 weeks post-surgery by 18±11 and 25±10%, respectively, compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation were 61±4 and 58±5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and exploration of these pathways may offer potential solutions for disuse atrophy of muscles.
Perch diameter and branching patterns have interactive effects on the locomotion and path choice of anole lizards
Authors: Jones Zachary M. , Jayne Bruce C. 
Published: May 2012

SUMMARYNatural branches vary conspicuously in their diameter, density and orientation, but how these latter two factors affect animal locomotion is poorly understood. Thus, for three species of arboreal anole lizards found on different size branches and with different limb lengths, we tested sprinting performance on cylinders with five diameters (5–100 mm) and five patterns of pegs, which simulated different branch orientations and spacing. We also tested whether the lizards preferred surfaces that enhanced their performance. The overall responses to different surfaces were similar among the three species, although the magnitude of the effects differed. All species were faster on cylinders with larger diameter and no pegs along the top. The short-limbed species was the slowest on all surfaces. Much of the variation in performance resulted from variable amounts of pausing among different surfaces and species. Lizards preferred to run along the top of cylinders, but pegs along the top of the narrow cylinders interfered with this. Pegs on top of the 100-mm diameter cylinder, however, had little effect on speed as the lizards ran quite a straight path alongside pegs without bumping into them. All three species usually chose surfaces with greater diameters and fewer pegs, but very large diameters with pegs were preferred to much smaller diameter cylinders without pegs. Our results suggest that preferring larger diameters in natural vegetation has a direct benefit for speed and an added benefit of allowing detouring around branches with little adverse effect on speed.
Reporting of post-polyethylene glycol prolactin: precipitation by polyethylene glycol 6000 or polyethylene glycol 8000 will change reference intervals for monomeric prolactin
Authors: Veljkovic Kika , Servedio Dominic , Don-Wauchope Andrew C 
Published: May 2012

Background When screening for macroprolactin, many laboratories use precipitation by polyethylene glycol (PEG) with molecular weight 6000 (PEG6000) or 8000 (PEG8000), and report the percentage prolactin recovery. It has been proposed that reporting of percentage prolactin recovery should be replaced by absolute post-PEG prolactin; however, the post-PEG prolactin reference interval has been established using PEG6000 only. We sought to determine whether the use of PEG8000, instead of PEG6000, changed post-PEG prolactin concentrations. Methods We compared the post-PEG6000 and post-PEG8000 prolactin concentrations in hyperprolactinaemic serum samples referred for macroprolactin screening ( n = 40), using Passing–Bablok regression analysis and Bland–Altman difference plot. Results The median (25th–75th percentile, range) total prolactin, post-PEG6000 and post-PEG8000 prolactin concentrations were, respectively, 36 (31–46, 23–83) μg/L, 27 (20–38, 18–72) μg/L and 24 (18–35, 16–64) μg/L for male serum samples ( n = 5); and 56 (39–83, 24–596) μg/L, 45 (31–67, 8–503) μg/L and 41 (28–62, 6–457) μg/L for female serum samples ( n = 35) (mIU/L conversion factor: 21.2). The Passing–Bablok analysis demonstrated a significant constant bias of −1.27 and a non-significant proportional bias of 0.96. The Bland–Altman plot showed a bias of −8.2% (95% limits of agreement −19.3–2.9%). Conclusions There is a significant constant bias between the two macroprolactin precipitation methods. We changed our PEG precipitation to a PEG6000 method. Laboratories that use PEG8000 should consider the transference of the reference interval established with PEG6000 carefully.
Sonnenfinsternisse und ihre chronologische Bedeutung: Ein neuer Sonnenfinsterniskanon für Altertumswissenschaftler
Authors: Gautschy Rita 
Published: May 2012

Zusammenfassung
In antiken Quellen sind zahlreiche astronomische Beobachtungen überliefert, die dazu benützt werden können, absolute Daten zu gewinnen. Besonders wichtig sind in diesem Zusammenhang Sonnenfinsternisse. Hier wird ein neuer elektronisch verfügbarer Sonnenfinsterniskanon präsentiert, der speziell an die Bedürfnisse von Altertumswissenschaftlern angepasst wurde: er enthält Karten aller Sonnenfinsternisse zwischen 2500 v. Chr. und 1000 n. Chr., die im ausgewählten geographischen Bereich zwischen (20° N, 5° O), (20° N, 50° O), (50° N, 5° O) und (50° N, 50° O) potentiell auffällig waren und somit für Identifikationen von Finsternisberichten aus diesem geographischen Bereich in Frage kommen, auch wenn sie nicht vorhergesagt wurden. Der Sonnenfinsterniskanon ist online verfügbar unter http://www.gautschy.ch/~rita/archast/solec/finsternis.html. Als Anwendungsbeispiele werden einerseits die Ugarit-Finsternis und andererseits die Ennius-Finsternis diskutiert.
Personifikationen von provinciae auf den Münzprägungen unter Hadrian: Auf den ikonographischen Spuren von ,Statthalterprovinzen‘ und ,Teilprovinzen‘
Authors: Vitale Marco 
Published: May 2012

Zusammenfassung
Die Gebietsnamen der Personifikationen auf den sog. Reiseerinnerungsmünzen des Kaisers Hadrian lassen sich alle als Bezeichnungen von administrativen Gebietseinheiten nachweisen. Sie vermitteln etwa im Unterschied zu den in einem offensichtlich militärisch-triumphalen Repräsentationskontext ausdrücklich als ἔϑνη veranschlagten Reliefdarstellungen im Sebasteion von Aphrodisias oder den literarisch mit Ethnika bezeichneten Darstellungen von gentes bzw. nationes der stadtrömischen porticus ad nationes nicht eine ethnographische Ansicht des römischen Reiches, sondern, entlang der reichsweiten Inspektionsreisen des Kaisers, eine an der administrativen Territorialordnung orientierte. Einerseits sind provinciae im Sinne umfassender Statthalterprovinzen, wie etwa Asia oder Dacia, angesprochen, wobei gleichnamige Statthalterprovinzen, wie etwa im Falle der drei provinciae namens Dacia oder der drei provinciae namens Hispania, sich nach einem formelhaften Abkürzungsprinzip jeweils umfassend durch das bloße gemeinsame Namenselement „Dacia“ bzw. „Hispania“ präsentieren. Andererseits erscheinen im engeren Sinne auch provinciae bzw. im Griechischen ἐπαρχίαι, also Teilprovinzen bzw. prokuratorische Verwaltungsgebiete unterhalb der Statthalterebene, wie im Falle der Münzlegenden Phrygia oder Libya. Diese Konzeption der Reichsgeographie ist wenigstens in der römischen Münzprägung kein Novum. Eine verwaltungsgeographische Perspektive unterworfener Regionen wird spätestens unter Trajan wenigstens in den Münzprägungen mit der personifizierten DACIA PROVINCIA ausdrücklich fassbar. Der Gebietsname Dacia bzw. seine Personifikation stand nunmehr selbstredend für die so genannte territorial definierte Verwaltungseinheit, stellte also weder die gleichnamige Landschaft noch ein ethnos dar.
Malignant and benign thyroid nodules after total body irradiation preceding hematopoietic cell transplantation during childhood
Authors: Vivanco Maritza , Dalle Jean-Hugues , Alberti Corinne , Lescoeur Brigitte , Yakouben Karima , Carel Jean-Claude , Baruchel André , Léger Juliane 
Published: May 2012

BackgroundThe risk of radiation-induced benign and malignant thyroid nodules is well known.ObjectiveThe aim of this study was to determine the occurrence of thyroid nodules and carcinomas after fractionated total body irradiation (TBI) preceding hematopoietic stem cell transplantation (HSCT) for malignant hematological disease during childhood.MethodsWe conducted a retrospective university hospital-based observational study. The participants were 76 patients receiving fractionated TBI between 1989 and 2009 as part of the conditioning regimen for HSCT to treat malignant hematological disease, with a median age of 8.2 (5.7–11.4) years, for whom the last ultrasound examination was performed at a median age of 14.2 (11.2–17) years. The main outcome measure was cumulative incidence of thyroid nodules detected by ultrasound scans followed by biopsy if necessary.ResultsThyroid nodules were examined in 21 (28%) patients, six (29%) of whom were diagnosed with thyroid carcinoma at the age of 2.2–18.6 years after TBI. The cumulative incidence of nodule occurrence increased with increasing time from diagnosis. The 10-year cumulative incidence of benign and malignant thyroid nodules was 16% (95% confidence interval (CI) 4–27%) and 8% (95% CI 0–16%) respectively. Seventeen (22%) patients had hypothyroidism (compensated n=12, in five patients it was transient). No significant independent risk factors were identified in the multivariable competing risk model as a function of nodule occurrence.ConclusionShort-term and life-long monitoring, with screening for nodules of the thyroid gland using ultrasound scans, is recommended for survivors subjected to TBI for HSCT during childhood.
A novel severe N-terminal splice site KISS1R gene mutation causes hypogonadotropic hypogonadism but enables a normal development of neonatal external genitalia
Authors: Breuer Oded , Abdulhadi-Atwan Maha , Zeligson Sharon , Fridman Hila , Renbaum Paul , Levy-Lahad Ephrat , Zangen David H 
Published: May 2012

BackgroundKisspeptin 1 receptor (KISS1R) gene mutations are rare but have recently become an important etiology of normosmic isolated hypogonadotropic hypogonadism (IHH).ObjectivesTo characterize the genetic defect, the phenotype, and response to therapy of three IHH siblings with a novel severe KISS1R mutation.Patients and methodsThree siblings (16- and 22-year-old sisters and their 20-year-old brother) born to consanguineous parents with normal neonatal external genitalia presented with no pubertal development, normosmia, and a low response to GNRH stimulation. Homozygosity mapping, KISS1R gene sequencing, and RNA expression were performed.ResultsThe females' basal low estradiol level (50 pmol/l) failed to rise in response to human chorionic gonadotropin (hCG). The brother's low testosterone (1.87 nmol/l) responded to combined hCG and human menopausal gonadotropin (hCG) and HMG therapies, but the testes remained small (1–2 ml). Secondary sexual characteristics were attained by exogenous sex steroid replacement. SNP array studies revealed shared homozygosity for a chromosome 19 region encompassing KISS1R. Sequencing revealed a novel homozygous KISS1R mutation at the nt-1 canonical acceptor splice site of intron 1 in affected siblings. The mother (menarche at 14 years) was heterozygous. cDNA sequencing showed that the G>A mutation results in skipping of exon 2 and a premature stop codon at residue 151.ConclusionsThe novel severe N-terminal KISS1R splice site (c.245−1G>A) mutation results in IHH. Heterozygous female carriers may manifest a subtle fertile phenotype. The subnormal gonadal response to hCG in patients may implicate a direct role of KISS1R in gonadal function. The normal neonatal virilization in a male homozygous to this severe mutation challenges the hypothesis that KISS1R is required for fetal development of male external genitalia.
Low-dose dexamethasone administration for 3 weeks favorably affects plasma HDL concentration and composition but does not affect very low-density lipoprotein kinetics
Authors: Wang Xuewen , Magkos Faidon , Patterson Bruce W , Reeds Dominic N , Kampelman Janine , Mittendorfer Bettina 
Published: May 2012

ObjectiveSubclinical hypercortisolemia often occurs in subjects with features of the metabolic syndrome, and it has been suggested that it may be, at least in part, responsible for the development of these metabolic abnormalities. However, the metabolic effects of glucocorticoid administration to mimic subclinical glucocorticoid excess have not been evaluated.MethodsWe used stable isotope-labeled tracer methods in conjunction with magnetic resonance techniques to measure the effect of glucocorticoid excess within the physiological range (∼0.7 mg dexamethasone/day for 3 weeks) on glucose and free fatty acid (FFA) rates of appearance (Ra) into plasma, intrahepatic triglyceride (TG) content, very low-density lipoprotein (VLDL)-TG and VLDL-apolipoprotein B-100 (apoB-100) kinetics and plasma lipoprotein subclass concentrations, and particle sizes in nine overweight and obese individuals.ResultsDexamethasone treatment led to a very small but significant increase in body weight (from 87.4±7.1 to 88.6±7.2 kg; P=0.003) and increased HDL-cholesterol (from 45.9±2.8 to 55.1±4.6 mg/dl; P=0.037) and HDL particle (from 33.7±2.2 to 41.4±4.2 nmol/l; P=0.023) concentrations in plasma but had no effect on intrahepatic TG content, glucose and FFA Ra in plasma, hepatic VLDL-TG and VLDL-apoB-100 secretion rates and mean residence times in the circulation, plasma TG and LDL-cholesterol concentrations, and plasma lipoprotein particle sizes.ConclusionSubclinical hypercortisolemia does not have significant adverse metabolic consequences.
Towards Novel Light-Activated Shape Memory Polymer: Thermomechanical Properties of Photo-responsive Polymers
Authors: Snyder Emily A. , Tong Tat H. 
Published: May 2012

AbstractThe basic principle for the operation of a thermally stimulated shape memory polymer (SMP) is a drastic change in elastic modulus above the glass transition temperature (Tg). This change from glassy modulus to rubbery modulus allows the material to be deformed above the Tg and retain the deformed shape when cooled below the Tg. The material will recover its original shape when heated above the Tg again. However, thermal activation is not the only possibility for a polymer to exhibit this shape memory effect or change of modulus. This paper discusses results of an alternative approach to SMP activation.It is well known that the Tg of a thermosetting polymer is proportional to its crosslinking density. It is possible for the crosslinking density of a room temperature elastomer to be modified through photo-crosslinking special photo-reactive monomer groups incorporated into the material system in order to increase its Tg. Correspondingly, the modulus will be increased from the rubbery state to the glassy state. As a result, the material is transformed from an elastomer to a rigid glassy photoset, depending on the crosslinking density achieved during exposure to the proper wavelength of light. This crosslinking process is reversible by irradiation with a different wavelength, thus making it possible to produce light-activated SMP materials that could be deformed at room temperature, held in deformed shape by photo-irradiation using one wavelength, and recovered to the original shape by irradiation with a different wavelength.In this work, monomers which contain photo-crosslinkable groups in addition to the primary polymerizable groups were synthesized. These monomers were formulated and cured with other monomers to form photo-responsive polymers. The mechanical properties of these materials, the kinetics, and the reversibility of the photo-activated shape memory effect were studied to demonstrate the effectiveness of using photo-irradiation to effect change in modulus (and thus shape memory effect).
Identifying the spatial scale of land use that most strongly influences overall river ecosystem health score
Authors: Sheldon Fran , Peterson Erin E. , Boone Ed L. , Sippel Suzanne , Bunn Stuart E. , Harch Bronwyn D. 
Published: May 2012

Catchment and riparian degradation has resulted in declining ecosystem health of streams worldwide. With restoration a priority in many regions, there is an increasing interest in the scale at which land use influences stream ecosystem health. Our goal was to use a substantial data set collected as part of a monitoring program (the Southeast Queensland, Australia, Ecological Health Monitoring Program data set, collected at 116 sites over six years) to identify the spatial scale of land use, or the combination of spatial scales, that most strongly influences overall ecosystem health. In addition, we aimed to determine whether the most influential scale differed for different aspects of ecosystem health. We used linear‐mixed models and a Bayesian model‐averaging approach to generate models for the overall aggregated ecosystem health score and for each of the five component indicators (fish, macroinvertebrates, water quality, nutrients, and ecosystem processes) that make up the score.Dense forest close to the survey site, mid‐dense forest in the hydrologically active near‐stream areas of the catchment, urbanization in the riparian buffer, and tree cover at the reach scale were all significant in explaining ecosystem health, suggesting an overriding influence of forest cover, particularly close to the stream. Season and antecedent rainfall were also important explanatory variables, with some land‐use variables showing significant seasonal interactions. There were also differential influences of land use for each of the component indicators. Our approach is useful given that restoring general ecosystem health is the focus of many stream restoration projects; it allowed us to predict the scale and catchment position of restoration that would result in the greatest improvement of ecosystem health in the regions streams and rivers. The models we generated suggested that good ecosystem health can be maintained in catchments where 80% of hydrologically active areas in close proximity to the stream have mid‐dense forest cover and moderate health can be obtained with 60% cover.