bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Therapies in Renal Replacement: The Effect of Two Different Potassium Acetate‐free Biofiltration Protocols on Striated Muscle Fibers
Authors: Coppolino Giuseppe , Bolignano Davide , Parisi Sergio , Aloisi Emanuele , Romeo Adolfo , Quartarone Angelo , Buemi Michele
Published: September 2007

Abstract:  Dramatic removal of potassium during hemodialysis sessions can induce changes in the electrical properties of nerve cells or muscle fibers, which may underlie neuromuscular symptoms referred by end‐stage renal disease patients. The primary aim of our study was to investigate the effects of acetate‐free biofiltration (AFB) on the amplitude of compound motor action potential (cMAP) obtained after stimulation of the ulnar nerve at the wrist. The secondary aim was to compare the effect of two different potassium removal modalities on cMAP amplitude and to analyze the effects on muscular force by specific dynamometric tests. Twenty‐eight patients received dialysis for 4 h, 3 times per week, first with standard AFB with constant potassium (AFB) and then with AFB with a variable concentration of potassium in the dialysis bath (AFBK). The amplitude of cMAP was determined after ulnar nerve stimulation at the wrist at different time intervals: at the start of dialysis; at 15, 45, 90, and 120 min after beginning the session; and at the end of treatment. At the same time intervals, muscle force generation was determined using a dynamometer. Finally, we measured plasma electrolytes, intraerythrocytic potassium, and the electrical membrane potential at rest (REMP) of the erythrocytic membrane. The main finding of this study was a significant reduction of cMAP amplitude in the first 45 min after AFB, which paralleled the reduction in serum potassium levels. Moreover, there was a reduction of muscular strength determined with dynamometric measurements. Potassium removal induced by the two different modalities of AFB may significantly affect myocardial and fibromuscular cells by modulating the electrochemical balance of cell membranes. The transient alteration of the electrical properties on voluntary striated muscle fibers may contribute to the brief reduction in muscular strength we detected in patients who underwent AFB. AFBK can minimize the negative effects of standard AFB treatment on neuromuscular excitability, most likely through a more gentle variation of potassium levels during dialysis.
A Case Report of Thrombotic Thrombocytopenic Purpura and Severe Acute Renal Failure Post Non‐myeloablative Allogeneic Peripheral Blood Stem Cell Transplantation Treated With Plasma Exchange and Hemodialysis
Authors: Kida Yujiro , Ishii Toshihide , Ando Minoru , Kanda Eiichiro , Suzuki Hitoe , Kida Aiko , Yamashita Takuya , Sakamaki Hisashi , Saito Hiroshi
Published: September 2007

Abstract:  A 59‐year‐old‐woman received related non‐myeloablative allogeneic peripheral blood stem cell transplantation (PBSCT) subsequent to autologous PBSCT in our hospital five years after she was diagnosed as oligo‐secretory myeloma. She was admitted to our hospital because of vomiting and grayish diarrhea 4 months after non‐myeloablative allogeneic PBSCT (mini‐alloPBSCT). Although her initial symptoms improved after admission, she gradually showed thrombocytopenia, anemia, and oliguria during the 2 weeks after admission. Our diagnosis was thrombotic thrombocytopenic purpura (TTP) and acute renal failure (ARF) secondary to mini‐alloPBSCT. After cessation of cyclosporine administration, we began to treat her with plasma exchange (PE) and hemodialysis. During the three and a half months after we started PE, the TTP gradually improved. Although PE had been reported to be ineffective for TTP post bone marrow transplantation, we could finally discontinue PE. In contrast, since her anuria continued, she was managed with hemodialysis. One month after PE was started, her activity of von Willebrand factor‐cleaving protease was 41% (normal range, >50%) and the ultrasonographic investigation of both kidneys was normal. She could be discharged after four and a half months hospitalization and lived well as an outpatient for a further two months. She died shortly after readmission from multiple organ failure without the relapse of TTP. The patient's clinical course would suggest that TTP post mini‐alloPBSCT could be treated with PE in some cases, despite the development of dialysis‐requiring severe ARF being a poor prognostic factor.
Inventory of water management practices in Harare, Zimbabwe
Authors: Nhapi Innocent
Published: September 2007

Lake Chivero, in Zimbabwe, is the major water supply source for the greater Harare area. This paper looks at the sustainability of current practices of the urban water cycle in relation to water quantity and quality management in the Chivero catchment. Data on population, water supply, water and wastewater treatment and river flows were obtained from urban councils and government departments. The data were used to assess water consumption, wastewater generation, treatment and disposal practices, river flow trends, raw water abstractions and water demand patterns. The results showed that the current situation is not sustainable as water quantity in the catchment will soon be a problem at current levels of consumption while water quality is already a problem, especially with regard to nutrient levels. Water and nutrient management strategies, which include water use efficiency, treatment and water recycling and nutrient reuse in controlled urban agriculture, are recommended as matters of urgency.
Epidermolysis bullosa acquisita in a great Dane
Authors: Hill P. B. , Boyer P. , Lau P. , Rybnicek J. , Hargreaves J. , Olivry T.
Published: September 2007

Autoimmune subepidermal blistering diseases in dogs were all classified as bullous pemphigoid until 1998. Since then, refinements in reagents and immunological techniques have allowed diseases which are histologically similar but which have a different molecular pathogenesis to be described. This report describes the first case of one such disease, epidermolysis bullosa acquisita, to be documented in the UK. The dog presented with a severe blistering and ulcerative disease affecting the oral cavity, pinnae and distal limbs. The diagnosis was confirmed by histopathology and direct and indirect immunofluorescent demonstration of immunoglobulin G reactivity to basement membrane antigens. Treatment with glucocorticoids, azathioprine, colchicine and an intravenous infusion of immunoglobulins resulted in complete resolution. The drugs were discontinued 12 months after the start of treatment and the dog remained in remission.
Toxoplasma gondii brain granuloma in a cat: diagnosis using cytology from an intraoperative sample and sequential magnetic resonance imaging
Authors: Falzone C. , Baroni M. , De Lorenzi D. , Mandara M. T.
Published: September 2007

A cat with a history of seizures and clinical suspicion of forebrain disorder underwent a brain magnetic resonance imaging. A space‐occupying lesion was identified in the left temporal lobe. The mass was surgically removed, and cytological, histological and immunohistochemical examinations documented the presence of Toxoplasma gondii. A definitive diagnosis of an intracranial T gondii granuloma was made. The cat was treated with clindamycin and phenobarbital and the seizures did not recur. After 10 months, a second magnetic resonance imaging showed severe brain atrophy, but T gondii granuloma recurrence was not noted. Twenty‐one months after surgery, the cat’s condition deteriorated, and another magnetic resonance imaging showed a presumptive recurrence of T gondii granuloma. In cats, T gondii granuloma must be considered as a differential diagnosis even when only a single intracranial mass is present. Cytology and magnetic resonance imaging can be useful in making a definitive diagnosis and to follow the evolution of the lesion.
Effects of aglepristone, a progesterone receptor antagonist, in a dog with a vaginal fibroma
Authors: Rollón E. , Millán Y. , De Las Mulas J. Martín
Published: September 2007

A 12‐year‐old, entire, nulliparous crossbreed female dog was presented with a history of vulval bleeding, bulging of the perineum and faecal tenesmus. A firm, non‐painful perineal mass, measuring 9·11×5·4 cm, with erythema was detected. Abdominal radiography showed compression and elevation of the rectal ampulla. A dose of 10 mg/kg aglepristone was administered subcutaneously on days 1, 2, 8, 15, 28 and 35. An incision biopsy was taken on day 15 and immunohistochemical analysis showed that the majority of neoplastic cells expressed progesterone receptors. Both the cutaneous erythema and the faecal tenesmus had resolved by day 28. A 50 per cent reduction in size was observed by day 60 (surgical excision). This study shows that benign tumours of the vagina of the dog that contain progesterone receptors can be reduced in size in a palliative or neoadjuvant setting using the progesterone receptor antagonist aglepristone.
Events in Syntax: Modification and Predication
Authors: Ramchand Gillian
Published: September 2007

What are the motivations for including event variables in our representations of natural language semantics? The article focuses narrowly on the issues that provided the basis for the original discussion in Davidson (1967), and seeks to explore its consequences for the advances in syntax and the interface that have taken place since then. The existence of an event variable in semantic representations is argued to be as necessary as it ever was, but a more articulated version of the traditional view is proposed to account for the full range of phenomena such as scope of adverbials, aspectual modification, and aktionsart. A range of important architectural issues arise concerning the relationships between syntax, semantics, and the lexicon once the Davidsonian position is taken seriously, an area that has proved fruitful for investigation and debate. In Section 3, the article gives an example of one kind of answer to the architectural question by proposing a radically decomposed syntax that is tightly correlated with the semantics of event structure, a theoretical position that could be called ‘post‐Davidsonianism’.
Phonological and Phonetic Characteristics of African American Vernacular English
Authors: Thomas Erik R.
Published: September 2007

The numerous controversies surrounding African American Vernacular English can be illuminated by data from phonological and phonetic variables. However, what is known about different variables varies greatly, with consonantal variables receiving the most scholarly attention, followed by vowel quality, prosody, and finally voice quality. Variables within each domain are discussed here and what has been learned about their realizations in African American speech is compiled. The degree of variation of each variable within African American speech is also summarized when it is known. Areas for which more work is needed are noted.
Effect of Fat Level on the Perception of Five Flavor Chemicals in Ice Cream with or without Fat Mimetics by Using a Descriptive Test
Authors: Liou B.K. , Grün I.U.
Published: September 2007

ABSTRACT:  Fat mimetics are commonly used in the manufacture of low‐fat and fat‐free ice creams. However, the use of fat mimetics affects flavor and texture characteristics of ice cream, which results in decreased overall acceptability by consumers. The initial objective of this study was to investigate the release behavior of 5 strawberry flavor compounds in ice creams with Simplesse®, Litesse®, and Litesse®/Simplesse® mixes using descriptive analysis. Fat mimetics and flavor formulation significantly influenced the perception of Furaneol™ (cooked sugar flavor), α‐ionone (violet flavor), and γ‐undecalactone (peach flavor), but there was no interaction between ice cream type and flavor formulation for the 3 flavors. Furaneol and ethyl‐3‐methyl‐3‐phenylglycidate (candy flavor) were perceived more strongly in full‐fat ice cream, while cis‐3‐hexen‐1‐ol (grassy flavor), α‐ionone, and γ‐undecalactone were perceived more strongly in low‐fat ice cream. Ice creams with Simplesse and full‐fat ice cream had similar sensory characteristics, while ice creams with Litesse were similar to low‐fat ice creams in flavor characteristics, and ice creams with Litesse/Simplesse mixes were closer in flavor profile to low‐fat ice cream but had similar texture properties to those of full‐fat ice cream. Simplesse was found to be a better fat mimetic for duplicating the flavor profiles and mouthfeel of full‐fat ice cream.
Efficacy of Two Acidic Sanitizers for Microbial Reduction on Metal Cans and Low‐Density Polyethylene Film Surfaces
Authors: Lee J. , Gupta M.J. , Lopes J. , Pascall M.A.
Published: September 2007

ABSTRACT:  This study investigated 2 sanitizer formulations and compared them with hydrogen peroxide (H2O2). Formulation number 1 contained citric acid and sodium dodecylbenzene sulfonate (SDBS). Formulation number 2 contained SDBS, citric, lactic, phosphoric acids, and benzoic acid. Low concentration levels of the sanitizers (1.0% for formulation 1 and 0.5% for formulation 2) were compared with 35% H2O2 for their efficacies on Escherichia coli, Listeria innocua, and Saccharomyces cerevisiae inoculated onto low‐density polyethylene (LDPE) films and metal cans at room temperature (23 ± 1 °C) and 40 °C. The results showed that both formulations 1 and 2 required >120 s to sanitize both materials from microbial populations at room temperature, while <15 s was needed for the H2O2. Except for formulation 1 on the E. coli inoculated LDPE film surface, the sanitizers completely eliminated the bacterial populations on both materials in 60 s at 40 °C. In general, the formulations were more effective for reduction of the microbial numbers on the can material when compared with the LDPE film. The E. coli showed greater tolerance for the sanitizers when exposed to the process conditions in this study. All sanitizers completely eliminated the test organisms in ≤36 s at 40 °C when tested on a commercial Benco Aseptic packaging machine.
Learning from Japanese Experience in Aged Care Policy
Authors: Tin Ng Guat
Published: September 2007

Like Singapore, Japan is projected to age rapidly. Japan is the first country in the world where more than 20% of the total population is over 65. Even as Japan adapts from western Europe and America where population ageing is more advanced up till now, it has been pioneering its own aged care policy, given the differences in sociocultural and political contexts. Of particular interest is its introduction of long‐term care insurance and its effectiveness in meeting the needs of the long‐term care of the aged and their family caregivers. In this article I seek to compare and contrast Singapore and Japan in terms of their demographic changes leading to rapid ageing, and their respective policy and program responses to a rapidly ageing population, drawing lessons from the Japanese experience.
Changes in synaptic transmission properties due to the expression of N‐type calcium channels at the calyx of Held synapse of mice lacking P/Q‐type calcium channels
Authors: Inchauspe Carlota González , Forsythe Ian D. , Uchitel Osvaldo D.
Published: September 2007

P/Q‐type and N‐type calcium channels mediate transmitter release at rapidly transmitting central synapses, but the reasons for the specific expression of one or the other in each particular synapse are not known. Using whole‐cell patch clamping from in vitro slices of the auditory brainstem we have examined presynaptic calcium currents (IpCa) and glutamatergic excitatory postsynaptic currents (EPSCs) at the calyx of Held synapse from transgenic mice in which the α1A pore‐forming subunit of the P/Q‐type Ca2+ channels is ablated (KO). The power relationship between Ca2+ influx and quantal output was studied by varying the number of Ca2+ channels engaged in triggering release. Our results have shown that more overlapping Ca2+ channel domains are required to trigger exocytosis when N‐type replace P/Q‐type calcium channels suggesting that P/Q type Ca2+ channels are more tightly coupled to synaptic vesicles than N‐type channels, a hypothesis that is verified by the decrease in EPSC amplitudes in KO synapses when the slow Ca2+ buffer EGTA‐AM was introduced into presynaptic calyces. Significant alterations in short‐term synaptic plasticity were observed. Repetitive stimulation at high frequency generates short‐term depression (STD) of EPSCs, which is not caused by presynaptic Ca2+ current inactivation neither in WT or KO synapses. Recovery after STD is much slower in the KO than in the WT mice. Synapses from KO mice exhibit reduced or no EPSC paired‐pulse facilitation and absence of facilitation in their presynaptic N‐type Ca2+ currents. Simultaneous pre‐ and postsynaptic double patch recordings indicate that presynaptic Ca2+ current facilitation is the main determinant of facilitation of transmitter release. Finally, KO synapses reveal a stronger modulation of transmitter release by presynaptic GTP‐binding protein‐coupled receptors (γ‐aminobutyric acid type B receptors, GABAB, and adenosine). In contrast, metabotropic glutamate receptors (mGluRs) are not functional at the synapses of these mice. These experiments reinforce the idea that presynaptic Ca2+ channels expression may be tuned for speed and modulatory control through differential subtype expression.
The passive, human calf muscles in relation to standing: the non‐linear decrease from short range to long range stiffness
Authors: Loram Ian D. , Maganaris Constantinos N. , Lakie Martin
Published: September 2007

During human standing, tonic ankle extensor torque is required to support the centre of mass (CoM) forward of the ankles, and dynamic torque modulation is required to maintain unstable balance. Passive mechanisms contribute to both but the extent is controversial. Some groups have revealed a substantial intrinsic stiffness (65–90%) normalized to load stiffness, ‘mgh’. Others regard their methodology as unsuitable for the low‐frequency conditions of quiet standing and believe the passive contribution to be small (10–15%). Here we applied low‐frequency ankle rotations to upright subjects who were supported at the waist allowing the leg muscles to be passive and we report normalized stiffness. The passive calf muscles provided: (i) an extensor torque capable of sustaining unstable balance without tonic activity at a mean CoM–ankle angle of 1.6 deg, (ii) a long range stiffness of 13 ± 2% and (iii) a short range (< 0.2 deg) stiffness of 67 ± 8%. Chordal ankle stiffness, derived from the torque versus angle relationship for 7 deg rotations, shows a non‐linear decrease (stiffness α rotation−0.33±0.04) from 101 ± 9% to 19 ± 5% for rotations of 0.03–7 deg, respectively. Thus, passive stiffness is well adapted for the continuum of postural and movement activity and has a substantial postural role eliminating the need for continuous muscle activity and increasing the unstable time constant of the human inverted pendulum. Ignoring the non‐linear dependence of passive stiffness on sway size could lead to serious misinterpretation of experiments using perturbations and sensory manipulations such as eye closure, sway referencing and altered support surfaces.
Surface dipole formation and lowering of the work function by Cs adsorption on InP(100) surface
Authors: Sun Yun , Liu Zhi , Pianetta Piero
Published: September 2007

The Cs adsorption on InP(100) surface is studied with synchrotron radiation photoelectron spectroscopy. The charge transfer from Cs to the InP substrate is observed from the Cs induced In 4d and P 2p components, and this charge transfer results in surface dipole formation and lowering of the work function. The Cs 4d intensity saturates at coverage of 1 ML. However, a break point is observed at 0.5 ML, which coincides with the achievement of the minimum work function. This break point is due to the different vertical placements of the first and the second half monolayer of Cs atoms. Based on this information, a simple bilayer structure for the Cs layer is presented. This bilayer structure is consistent with the behavior of the charge transfer from the Cs to the InP substrate at different Cs coverages. This, in turn, explains why the work function decreases to a minimum at 0.5 ML of Cs and remains almost constant beyond this coverage. The depolarization of the surface dipoles is attributed to the saturation of charge transfer to the surface In atoms and the polarization of the Cs atoms in the second half monolayer induced by the positively charged Cs atoms in the first half monolayer.
Molecular dynamics simulations of 30 and 2keV Ga in Si
Authors: Giannuzzi Lucille A. , Garrison Barbara J.
Published: September 2007

Focused Ga+ ion beams are routinely used at high incident angles for specimen preparation. Molecular dynamics simulations of 2 and 30keV Ga bombardment of Si(011) at a grazing angle of 88° were conducted to assess sputtering characteristics and damage depth. The bombardment of atomically flat surfaces and surfaces with vacancies shows little energy transfer yielding ion reflection. The bombardment of surfaces with adatoms allows for the coupling of the energy of motion parallel to the surface into the substrate resulting in sputtering. The adatom and one other Si atom eject, and motion in the substrate occurs down to a depth of 13Å. Experimental evidence shows that sputtering is a reality, suggesting that an atomically flat surface is never achieved.
Thermal stability of sputtered intermetallic Al–Au coatings
Authors: Moser M. , Mayrhofer P. H. , Ross I. M. , Rainforth W. M.
Published: September 2007

Recently, the authors have shown that single-phase Al2Au coatings, prepared by unbalanced magnetron sputtering, exhibit a dense columnar structure and highest hardness and indentation moduli of 8 and 144GPa, respectively, within the Al–Au films investigated. This study focuses on the thermal stability of Al2Au with respect to films containing more Al and Au having Al∕Au at. % ratios of 4.32 and 1.85, respectively. Single-phase Al2Au has the highest onset temperature for recovery of 475°C and recrystallization of 575°C. Upon annealing Au- and Al-rich films, their stresses deviate from the linear thermoelastic behavior at temperatures (T) above 200 and 450°C, respectively, due to pores and metallic phases present. Metastable Au within the as-deposited Au-rich film is consumed by the growing intermetallic AlAu and AlAu2 phases at T⩾450°C, which themselves melt at ∼625°C. Due to nanometer scale segregations of Al, encapsulated by Al2Au in Al-rich coatings, their melting point is reduced by ∼85°Cto575°C. Dynamic thermal analyses up to 1100°C in synthetic air reveal the single-phase Al2Au films with a superior thermal stability and only negligible oxidation. At 750°C, the mass gain is ∼1.5mg∕cm2 after 50h isothermal exposure. Based on the investigations, the authors can conclude that single-phase intermetallic Al2Au films have a high potential for oxidation protection of sensitive materials.
Bonding statistics and electronic structure of novel Si–B–C–N materials: Ab initio calculations and experimental verification
Authors: Houška Jiří , Čapek Jiří , Vlček Jaroslav , Bilek M. M. M. , McKenzie D. R.
Published: September 2007

Amorphous silicon-boron-carbon-nitrogen alloys were deposited by reactive magnetron sputtering, and their bonding statistics and electronic structure were investigated using a combined approach of experiment and molecular dynamics simulations. The authors show a difference between Si-based and C-based Si–B–C–N networks, and investigate coordination numbers and behavior of individual atom types. Furthermore, the authors calculate electronic structure and photoconductivity of the materials. The authors find that both a higher Si∕C ratio and an addition of hydrogen increase a band gap of the materials.
Growth stress buildup in ion beam sputtered Mo thin films and comparative study of stress relaxation upon thermal annealing or ion irradiation
Authors: Debelle A. , Abadias G. , Michel A. , Jaouen C. , Pelosin V.
Published: September 2007

In an effort to address the understanding of the origin of growth stress in thin films deposited under very energetic conditions, the authors investigated the stress state and microstructure of Mo thin films grown by ion beam sputtering (IBS) as well as the stress relaxation processes taking place during subsequent thermal annealing or ion irradiation. Different sets of samples were grown by varying the IBS deposition parameters, namely, the energy E0 and the flux j of the primary ion beam, the target-to-sputtering gas mass ratio M1∕M2 as well as film thickness. The strain-stress state was determined by x-ray diffraction using the sin2ψ method and data analyzed using an original stress model which enabled them to correlate information at macroscopic (in terms of stress) and microscopic (in terms of defect concentration) levels. Results indicate that these refractory metallic thin films are characterized by a high compressive growth stress (−2.6to−3.8GPa), resulting from the creation of a large concentration (up to ∼1.4%) of point or cluster defects, due to the atomic peening mechanism. The M1∕M2 mass ratio enables tuning efficiently the mean deposited energy of the condensing atoms; thus, it appears to be the more relevant deposition parameter that allows modifying both the microstructure and the stress level in a significant way. The growth stress comes out to be highly unstable. It can be easily relaxed either by postgrowth thermal annealing or ion irradiation in the hundred keV range at very low dose [<0.1dpa (displacement per atom)]. It is shown that thermal annealing induces deleterious effects such as oxidation of the film surface, decrease of the film density, and in some cases adhesion loss at the film/substrate interface, while ion irradiation allows controlling the stress level without generating any macroscopic damage.
Characterization of Ce–Pd(111) and Ce–Pd(110) surface alloys
Authors: Tollefsen H. , Berstad L. J. , Raaen S.
Published: September 2007

Cerium-palladium surface alloys have been studied by x-ray and ultraviolet photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), and photoemission electron microscopy. Desorption of CO has been studied by temperature programed desorption spectroscopy. Thin layers of Ce were deposited on Pd(111) and Pd(110) single crystal substrates to form surface alloys upon annealing to 1000K. An enrichment of Pd at the surface is observed and the work functions of the surface alloys are found to be 0.2–0.6eV less than the value for the bare Pd substrate, which are substantially larger than the values for the as-deposited Ce–Pd samples. Several different LEED patterns were observed depending on the annealing temperature. The estimated Ce valence from XPS was found to be in the range from 3.16 to 3.22 for the surface alloys after annealing.
Modeling of magnetically enhanced capacitively coupled plasma sources: Two frequency discharges
Authors: Yang Yang , Kushner Mark J.
Published: September 2007

Magnetically enhanced, capacitively coupled radio frequency plasma sources are finding continued use for etching of materials for microelectronics fabrication at a time when multifrequency sources are also being developed. Magnetically enhanced reactive ion etching (MERIE) sources typically use magnetic fields of tens to hundreds of Gauss parallel to the substrate to either increase the plasma density at a given pressure or to lower the operating pressure. Multifrequency sources are used to separately control the magnitude of the ion and radical fluxes (typically with a high frequency source) and the ion energy distributions (typically with a low frequency) to the substrate. In this article, the properties of a two-frequency MERIE reactor are discussed using results from a computational investigation. As in single frequency sources, the reduction in transverse electron mobility as the magnetic field increases can produce a reversal of the electric field in the sheath and an increase in voltage drop across the bulk plasma. These trends decrease ion energies and increase the angular spread of ions. Similar trends are found here, including a field reversal in the sheath at the high frequency electrode. These effects produce a coupling between the high and low frequency sources that compromise the independence of ion production and ion acceleration by the two sources.
A Basal Dromaeosaurid and Size Evolution Preceding Avian Flight
Authors: Turner Alan H. , Pol Diego , Clarke Julia A. , Erickson Gregory M. , Norell Mark A.
Published: September 2007

Fossil evidence for changes in dinosaurs near the lineage leading to birds and the origin of flight has been sparse. A dinosaur from Mongolia represents the basal divergence within Dromaeosauridae. The taxon's small body size and phylogenetic position imply that extreme miniaturization was ancestral for Paraves (the clade including Avialae, Troodontidae, and Dromaeosauridae), phylogenetically earlier than where flight evolution is strongly inferred. In contrast to the sustained small body sizes among avialans throughout the Cretaceous Period, the two dinosaurian lineages most closely related to birds, dromaeosaurids and troodontids, underwent four independent events of gigantism, and in some lineages size increased by nearly three orders of magnitude. Thus, change in theropod body size leading to flight's origin was not unidirectional.
A Neuroligin-3 Mutation Implicated in Autism Increases Inhibitory Synaptic Transmission in Mice
Authors: Tabuchi Katsuhiko , Blundell Jacqueline , Etherton Mark R. , Hammer Robert E. , Liu Xinran , Powell Craig M. , Südhof Thomas C.
Published: September 2007

Autism spectrum disorders (ASDs) are characterized by impairments in social behaviors that are sometimes coupled to specialized cognitive abilities. A small percentage of ASD patients carry mutations in genes encoding neuroligins, which are postsynaptic cell-adhesion molecules. We introduced one of these mutations into mice: the Arg
451
→Cys
451
(R451C) substitution in neuroligin-3. R451C mutant mice showed impaired social interactions but enhanced spatial learning abilities. Unexpectedly, these behavioral changes were accompanied by an increase in inhibitory synaptic transmission with no apparent effect on excitatory synapses. Deletion of neuroligin-3, in contrast, did not cause such changes, indicating that the R451C substitution represents a gain-of-function mutation. These data suggest that increased inhibitory synaptic transmission may contribute to human ASDs and that the R451C knockin mice may be a useful model for studying autism-related behaviors.
Muscular Thin Films for Building Actuators and Powering Devices
Authors: Feinberg Adam W. , Feigel Alex , Shevkoplyas Sergey S. , Sheehy Sean , Whitesides George M. , Parker Kevin Kit
Published: September 2007

We demonstrate the assembly of biohybrid materials from engineered tissues and synthetic polymer thin films. The constructs were built by culturing neonatal rat ventricular cardiomyocytes on polydimethylsiloxane thin films micropatterned with extracellular matrix proteins to promote spatially ordered, two-dimensional myogenesis. The constructs, termed muscular thin films, adopted functional, three-dimensional conformations when released from a thermally sensitive polymer substrate and were designed to perform biomimetic tasks by varying tissue architecture, thin-film shape, and electrical-pacing protocol. These centimeter-scale constructs perform functions as diverse as gripping, pumping, walking, and swimming with fine spatial and temporal control and generating specific forces as high as 4 millinewtons per square millimeter.
Unequal summer use of beaver ponds by river otters: influence of beaver activity, pond size, and vegetation cover
Authors: LeBlanc F.A. , Gallant D. , Vasseur L. , Léger L.
Published: September 2007

River otters ( Lontra canadensis (Schreber, 1777)) and beavers ( Castor canadensis Kuhl, 1820) are semi-aquatic mammals that can occur sympatrically in freshwater ecosystems of North America, including beaver ponds. Although little research has been done on the relationship between these species, it has been described as commensal. Relatively little is known about what pond characteristics potentially influence otter use. During the summer of 2004, we documented otter activity signs (i.e., feces) at 56 beaver ponds located in Kouchibouguac National Park of Canada, along the east coast of New Brunswick. We sought to identify which of 16 variables describing pond attributes were related to otter use. Otter activity at beaver ponds was positively associated with beaver presence, pond size, and vegetation cover. We discuss how these pond characteristics can benefit otters in terms of two key habitat needs, availability of prey and shelter. Our results are a first indication that the source–sink dynamic of beavers, whereby ponds are created, expanded, and abandoned, will create a mosaic of ponds that ultimately influences the river otter’s own pattern of habitat use and distribution.
Genetic variation and evidence for population structure in eastern North Pacific false killer whales (Pseudorca crassidens)
Authors: Chivers Susan J. , Baird Robin W. , McSweeney Daniel J. , Webster Daniel L. , Hedrick Nicole M. , Salinas Juan Carlos
Published: September 2007

False killer whales ( Pseudorca crassidens (Owen, 1846)) are incidentally taken in the North Pacific pelagic long-line fishery, but little is known about their population structure to assess the impact of these takes. Using mitochondrial DNA (mtDNA) control region sequence data, we quantified genetic variation for the species and tested for genetic differentiation among geographic strata. Our data set of 124 samples included 115 skin-biopsy samples collected from false killer whales inhabiting the eastern North Pacific Ocean (ENP), and nine samples collected from animals sampled at sea or on the beach in the western North Pacific, Indian, and Atlantic oceans. Twenty-four (24) haplotypes were identified, and nucleotide diversity was low (π = 0.37%) but comparable with that of closely related species. Phylogeographic concordance in the distribution of haplotypes was revealed and a demographically isolated population of false killer whales associated with the main Hawaiian islands was identified (ΦST= 0.47, p < 0.0001). This result supports recognition of the existing management unit, which has geo-political boundaries corresponding to the USA’s exclusive economic zone (EEZ) of Hawai‘i. However, a small number of animals sampled within the EEZ but away from the near-shore island area, which is defined as <25 nautical miles (1 nautical mile = 1.852 km) from shore, had haplotypes that were the same or closely related to those found elsewhere in the ENP, which suggests that there may be a second management unit within the Hawaiian EEZ. Biologically meaningful boundaries for the population(s) cannot be identified until we better understand the distribution and ecology of false killer whales.
Eavesdropping by bats on the feeding buzzes of conspecifics
Authors: Gillam E.H.
Published: September 2007

Echolocation calls of most bats are emitted at high intensities and subject to eavesdropping by nearby conspecifics. Bats may be especially attentive to “feeding buzz” calls, which are emitted immediately before attack on airborne insects and indicate the potential presence of prey in the nearby area. Although previous work has shown that some species are attracted to feeding buzzes, these studies did not provide a well-controlled test of eavesdropping, as comparisons were made between responses to natural and altered signals (e.g., forward versus backward broadcasts of calls). In this study, I assessed the importance of feeding buzzes by conducting playbacks of controlled echolocation stimuli. I presented free-flying Brazilian free-tailed bats, Tadarida brasiliensis (I. Geoffroy, 1824), with echolocation call sequences in which feeding buzz calls were either present or absent, as well as a silence control. I determined levels of bat activity by counting the number of echolocation calls and bat passes recorded in the presence of each stimulus, and found significantly greater bat activity in response to broadcasts that contained feeding buzzes than to broadcasts without feeding buzzes or to the silence control. These results indicate that bats are especially attentive to conspecific feeding buzz calls and that eavesdropping may allow a bat to more readily locate rich patches of insect prey.
Effects of flood suppression on natricine snake diet and prey overlap
Authors: Hampton Paul M. , Ford Neil B.
Published: September 2007

Organisms may become adapted to disturbances when these disturbances occur periodically and at intermediate intensity. To investigate the effects of flood suppression, this study compared diet and competition of semi-aquatic snakes during flood (2000–2001) and no flood (2003–2005) years. Three natricine species, Nerodia erythrogaster (Forster in Bossu, 1771), Nerodia fasciata (L., 1766), and Thamnophis proximus (Say in James, 1823), were palpated for prey items in an east Texas floodplain under both conditions. Prey items were classified as crayfish, salamanders, anurans, or fish. Simpson’s diversity index of prey, frequency of consumed prey type, and prey importance values were compared between flood and no flood years. Pianka’s index of niche overlap was used to compare changes in diet overlap between species in the years with floods and those without. In the absence of floods, the number of prey types consumed by N. erythrogaster and T. proximus decreased. The frequency of prey types consumed during flood years was significantly different from the period of flood suppression for all three species. The order of prey importance also changed in the absence of floods for all three snake species. Without floods, diet overlap decreased between N. erythrogaster and the other two species; however, overlap between N. fasciata and T. proximus doubled.
Cell-specific effects of insulin receptor substrate-1 deficiency on normal and IGF-I-mediated colon growth
Authors: Simmons J. G. , Ling Y. , Wilkins H. , Fuller C. R. , D'Ercole A. J. , Fagin James , Lund P. K.
Published: September 2007

Insulin-like growth factor I (IGF-I) potently stimulates intestinal growth. Insulin receptor substrate-1 (IRS-1) mediates proliferative and antiapoptotic actions of IGF-I in cell lines, but its in vivo relevance in intestine is not defined. This study tested the hypothesis that there is cell type-specific dependence on IRS-1 as a mediator of IGF-I action. Length, mass, crypt cell proliferation, and apoptosis were measured in small intestine and colon of IRS-1-null mice and wild-type (WT) littermates and in colon of IRS-1-null or WT mice expressing IGF-I transgenes. Expression of IGF-I receptor and signaling intermediates was examined in intestine of WT and IRS-1-null mice, cultured intestinal epithelial cells, and myofibroblasts. Absolute IRS-1 deficiency reduced mucosal mass in jejunum and colon, but effects were more pronounced in colon. Muscularis mass was decreased in both segments. In IGF-I transgenics, IRS-1 deficiency significantly attenuated IGF-I-stimulated growth of colonic mucosa and abolished antiapoptotic but not mitogenic effects of IGF-I transgene on crypt cells. IGF-I-induced muscularis growth was unaffected by IRS-1 deficiency. In intestinal epithelial cells, IRS-1 was expressed at higher levels than IRS-2 and was preferentially activated by IGF-I. In contrast, IGF-I activated both IRS-1 and IRS-2 in intestinal myofibroblasts and IRS-2 activation was upregulated in IRS-1-null myofibroblasts. We conclude that the intestinal epithelium but not the muscularis requires IRS-1 for normal trophic actions of IGF-I and that IRS-1 is required for antiapoptotic but not mitogenic effects of IGF-I in the intestinal crypts in vivo.
Raphe magnus nucleus is involved in ventilatory but not hypothermic response to CO2
Authors: Dias Mirela B. , Nucci Tatiane B. , Margatho Lisandra O. , Antunes-Rodrigues José , Gargaglioni Luciane H. , Branco Luiz G. S.
Published: September 2007

There is evidence that serotonin [5-hydroxytryptamine (5-HT)] is involved in the physiological responses to hypercapnia. Serotonergic neurons represent the major cell type (comprising 15–20% of the neurons) in raphe magnus nucleus (RMg), which is a medullary raphe nucleus. In the present study, we tested the hypothesis 1) that RMg plays a role in the ventilatory and thermal responses to hypercapnia, and 2) that RMg serotonergic neurons are involved in these responses. To this end, we microinjected 1) ibotenic acid to promote nonspecific lesioning of neurons in the RMg, or 2) anti-SERT-SAP (an immunotoxin that utilizes a monoclonal antibody to the third extracellular domain of the serotonin reuptake transporter) to specifically kill the serotonergic neurons in the RMg. Hypercapnia caused hyperventilation and hypothermia in all groups. RMg nonspecific lesions elicited a significant reduction of the ventilatory response to hypercapnia due to lower tidal volume (Vt) and respiratory frequency. Rats submitted to specific killing of RMg serotonergic neurons showed no consistent difference in ventilation during air breathing but had a decreased ventilatory response to CO2 due to lower Vt. The hypercapnia-induced hypothermia was not affected by specific or nonspecific lesions of RMg serotonergic neurons. These data suggest that RMg serotonergic neurons do not participate in the tonic maintenance of ventilation during air breathing but contribute to the ventilatory response to CO2. Ultimately, this nucleus may not be involved in the thermal responses to CO2.
Activation of Holliday Junction–Recognizing Protein Involved in the Chromosomal Stability and Immortality of Cancer Cells
Authors: Kato Tatsuya , Sato Nagato , Hayama Satoshi , Yamabuki Takumi , Ito Tomoo , Miyamoto Masaki , Kondo Satoshi , Nakamura Yusuke , Daigo Yataro
Published: September 2007

We identified a novel gene HJURP (Holliday junction–recognizing protein) whose activation seemed to play a pivotal role in the immortality of cancer cells. HJURP was considered a possible downstream target for ataxia telangiectasia mutated signaling, and its expression was increased by DNA double-strand breaks (DSB). HJURP was involved in the homologous recombination pathway in the DSB repair process through interaction with hMSH5 and NBS1, which is a part of the MRN protein complex. HJURP formed nuclear foci in cells at S phase and those subjected to DNA damage. In vitro assays implied that HJURP bound directly to the Holliday junction and rDNA arrays. Treatment of cancer cells with small interfering RNA (siRNA) against HJURP caused abnormal chromosomal fusions and led to genomic instability and senescence. In addition, HJURP overexpression was observed in a majority of lung cancers and was associated with poor prognosis as well. We suggest that HJURP is an indispensable factor for chromosomal stability in immortalized cancer cells and is a potential novel therapeutic target for the development of anticancer drugs. [Cancer Res 2007;67(18):8544–53]
MicroRNA-34b and MicroRNA-34c Are Targets of p53 and Cooperate in Control of Cell Proliferation and Adhesion-Independent Growth
Authors: Corney David C. , Flesken-Nikitin Andrea , Godwin Andrew K. , Wang Wei , Nikitin Alexander Yu.
Published: September 2007

MicroRNAs (miRNA) are a recently discovered class of noncoding RNAs that negatively regulate gene expression. Recent evidence indicates that miRNAs may play an important role in cancer. However, the mechanism of their deregulation in neoplastic transformation has only begun to be understood. To elucidate the role of tumor suppressor p53 in regulation of miRNAs, we have analyzed changes in miRNA microarray expression profile immediately after conditional inactivation of p53 in primary mouse ovarian surface epithelium cells. Among the most significantly affected miRNAs were miR-34b and miR-34c, which were down-regulated 12-fold according to quantitative reverse transcription–PCR analysis. Computational promoter analysis of the mir-34b/mir-34c locus identified the presence of evolutionarily conserved p53 binding sites ∼3 kb upstream of the miRNA coding sequence. Consistent with evolutionary conservation, mir-34b/mir-34c were also down-regulated in p53-null human ovarian carcinoma cells. Furthermore, as expected from p53 binding to the mir-34b/c promoter, doxorubicin treatment of wild-type, but not p53-deficient, cells resulted in an increase of mir-34b/mir-34c expression. Importantly, miR-34b and miR-34c cooperate in suppressing proliferation and soft-agar colony formation of neoplastic epithelial ovarian cells, in agreement with the partially overlapping spectrum of their predicted targets. Taken together, these results show the existence of a novel mechanism by which p53 suppresses such critical components of neoplastic growth as cell proliferation and adhesion-independent colony formation. [Cancer Res 2007;67(18):8433–8]
Adaptation of Vasomotor Function of Human Coronary Arterioles to the Simultaneous Presence of Obesity and Hypertension
Authors: Fulop Tibor , Jebelovszki Eva , Erdei Nora , Szerafin Tamas , Forster Tamas , Edes Istvan , Koller Akos , Bagi Zsolt
Published: September 2007

Objectives—

We hypothesized that simultaneous presence of obesity and hypertension activates adaptive vascular mechanisms affecting dilations of human coronary arterioles.

Methods and Results—

Agonist-induced dilations were assessed in isolated pressurized coronary arterioles from patients (n=38) who underwent cardiac surgery. Among normotensives we found that dilations to bradykinin (BK) and the NO-donor, sodium-nitroprusside (SNP) were reduced in obese subjects (BK, 10
−7
mol/L, lean:90±4%, obese:64±7%; SNP, 10
−6
mol/L, lean:89±7%, obese:76±5%). However, among hypertensives, both BK- and SNP-induced dilations were significantly enhanced in obese patients, when compared with lean individuals (BK, lean:71±7%, obese:85±3%; SNP, lean:60±6%, obese:83±2%). Correspondingly, in hypertensive patients, but not in those of normotensives, a positive correlation was found between body mass index (BMI) and BK-induced (
P
=0.036,
r
=0.46), and also SNP-evoked (
P
=0.031,
r
=0.44) coronary dilations. Moreover, in additional 55 hypertensive patients flow-mediated (FMD) and nitroglycerin (NTG)-induced dilations of the brachial artery were assessed. In obese hypertensive individuals, FMD- and NTG-induced dilations were greater (FMD:6.2±0.7%, NTG:17.2±0.9%), than in lean hypertensive patients (FMD:3.7±0.6%, NTG:13.6±1.1%). Correspondingly, FMD- and NTG-induced dilations were positively correlated with BMI (
P
=0.020,
r
=0.31 and
P
=0.033,
r
=0.29, respectively).

Conclusions—

These findings are the first to suggest that obesity may lead to activation of adaptive vascular mechanisms to enhance the dilator function of coronary and peripheral arterial vessels in hypertensive patients.