bluuebunny/crossref_metadata_2025 huggingface dataset:
The Nursing Practice Environment
Authors: Lake Eileen T.
Published: April 2007

Improvements in nurses' practice environments are essential to retain nurses and keep patients safe. The pace of improvements can accelerate if evidence is translated clearly for researchers, managers, and policymakers. This article evaluates the utility of published multidimensional instruments to measure the nursing practice environment. The assessment criteria are theoretical relevance, ease of use, and dissemination. This article also synthesizes the research that has used these instruments. Seven instruments and 54 studies are evaluated. The Practice Environment Scale of the Nursing Work Index (PES-NWI) is proposed as the most useful instrument. Its content, length, and dissemination best satisfy the set of criteria. Researchers should use the PES-NWI to generate consistent and comparable evidence; expand the content to reflect all conceptual domains; develop a short form; test the instrument in different care settings; expand the evidence of the practice environment's influence on patient outcomes; and test interventions for practice environment improvements.
Performance Measurement of Nursing Care
Authors: Needleman Jack , Kurtzman Ellen T. , Kizer Kenneth W.
Published: April 2007

Concerns about nurse staffing in hospitals, nursing's influence on patient safety and health care outcomes, and nurses' work environment (e.g., equipment failures, documentation burden) have led to increased interest in measuring and reporting nursing's performance. This article reviews recent efforts and issues involved in identifying a set of nursing-sensitive performance measures. Sustaining and strengthening current efforts requires developing measures that address all the domains of nursing, addressing technical issues needed to analyze the impact of nursing on patient safety and health care outcomes, developing data systems that provide the information needed to implement the model system, regularly improving the set of endorsed standards to reflect the most current science and empirical evidence, and persuading all health care stakeholders that measurement and reporting nursing-sensitive standards make a difference in the care and quality that are delivered. Each of these tasks requires substantial development work and construction and maintenance of the infrastructure to sustain the performance measurement efforts.
Upregulation of Apolipoprotein B Secretion, but Not Lipid, by Tumor Necrosis Factor‐α in Rat Hepatocyte Cultures in the Absence of Extracellular Fatty Acids
Authors: BARTOLOMÉ NEREA , RODRÍGUEZ LORENA , MARTÍNEZ MARÍA J. , OCHOA BEGOÑA , CHICO YOLANDA
Published: April 2007

Abstract:  Tumor necrosis factor‐α (TNF‐α) plays a pivotal role in the host response to infection. Rapidly liberated to the bloodstream, TNF‐α triggers the production of other cytokines and the acute‐phase response. Hypertriglyceridemia is a sepsis hallmark associated with high plasma levels of very low‐density lipoprotein (VLDL) particles, partly ascribed to increased hepatic production. The kinetics of the hepatocyte response, the cytokine/s responsible, and the underlying mechanisms are not fully elucidated. VLDL biogenesis is a complex, time‐consuming process that depends on lipid availability and microsomal triglyceride transfer protein (MTP) activity for correct apolipoprotein B (apoB) lipidation. Studies were performed to define the direct effect of TNF‐α on VLDL secretion rate and composition in rat hepatocytes cultured in conditions resembling the fed situation. Increases of 17–24% in the number of VLDL particles secreted and of 44–88% in the cellular levels of apoB mRNA were caused by 5, 20, or 100 ng/mL TNF‐α in 8 h. Lipoprotein secretion returned to baseline levels in 16 h, whereas TNF‐α‐treated cells continued to exhibit higher apoB transcript levels. The mass of each lipid class in secreted VLDL and of MTP mRNA in cells was not affected by any of the tested TNF‐α doses or treatment periods. These findings indicate that over a wide range of concentrations, TNF‐α was capable of inducing sustained upregulation of apoB mRNA expression and transient increase in secretion of its protein, but, apparently, VLDL triglyceride secretion was not a TNF‐α target under conditions in which fatty acids were not extracellularly provided.
Alterations of Synaptic Turnover Rate in Aging May Trigger Senile Plaque Formation and Neurodegeneration
Authors: BERTONI‐FREDDARI CARLO , FATTORETTI PATRIZIA , GIORGETTI BELINDA , GROSSI YESSICA , BALIETTI MARTA , CASOLI TIZIANA , DI STEFANO GIUSEPPINA , PERRETTA GEMMA
Published: April 2007

Abstract:  The changes of synaptic ultrastructure were investigated by morphometry in the frontal (FC) and temporal (TC) cortex of adult and aged monkeys, to assess the potential role of age‐related synaptic deterioration in neurodegeneration. The average synaptic size (S), the synaptic numeric density (Nv: number of synapses/μm3 of tissue), the synaptic surface density (Sv: overall area of synaptic junctional zones/μm3 of tissue), and the number of synapses/neuron (Syn/Neur) were calculated. In FC, significant differences of Nv and Sv due to age were not revealed, while the S value was significantly increased in the aged animals. In TC, Sv did not change in relation to age, whereas Nv was significantly decreased and S significantly increased in aged monkeys. A percent distribution of S showed that the fraction of enlarged synapses (>0.20 μm2) was higher in TC than in FC, regardless of the age of the animals (21.3% versus 16.9% in adult and 33.9% versus 26.0% in aged monkeys, respectively). In aged animals, Syn/Neur was not significantly decreased in TC and not significantly increased in FC (4.4%). The above morphometric parameters account for the ongoing rearrangements of synaptic ultrastructure, reacting to the environmental stimuli. Our findings provide evidence of an age‐related decline of synaptic plasticity in the brain of aged monkeys that is statistically significant in TC. According to current literature data on synaptic structural dynamics, this decay may represent an early and subtle alteration able to trigger the development of senile plaques and neurodegenerative events.
Immunohistochemical Evidence for Impaired Neuregulin‐1 Signaling in the Prefrontal Cortex in Schizophrenia and in Unipolar Depression
Authors: BERTRAM IRIS , BERNSTEIN HANS‐GERT , LENDECKEL UWE , BUKOWSKA ALICJA , DOBROWOLNY HENRIK , KEILHOFF GERBURG , KANAKIS DIMITRIOS , MAWRIN CHRISTIAN , BIELAU HENDRIK , FALKAI PETER , BOGERTS BERNHARD
Published: April 2007

Abstract:  In the central nervous system (CNS), neuregulin‐1 (NRG‐1) proteins function in neuronal migration, differentiation, and survival of oligodendrocytes. The NRG‐1 gene codes for at least 15 different isoforms, which may be classified on the basis of their molecular structure. At least two different haplotypes of the NRG‐1 gene may be associated with schizophrenia. An abnormal expression pattern of NRG‐1 mRNA was found in the prefrontal cortex of schizophrenic patients in comparison to controls. We here show that the NRG‐1α isoform is significantly reduced in white matter of the prefrontal cortex in schizophrenia but not in affective disorder. In the prefrontal gray matter, the density of NRG‐1α expressing neurons was reduced in individuals with schizophrenia and in unipolar patients. We studied brains of 22 schizophrenics, 12 patients with affective disorders (7 unipolar and 5 bipolar), and 22 matched controls. NRG‐1α immunoreactive material was detected with a polyclonal antiserum against the synthetic peptide from α‐type EGF‐like domain of human NRG. The demonstrated decreased number of NRG‐1 immunoreactive neurons in the brains of schizophrenics and patients with unipolar depression points to an important role of this NRG‐1α splice variant in neuropsychiatric disorders. Reduced NRG‐1α protein concentrations were found in brains of schizophrenics after Western blot analysis. The diminished expression of NRG‐1α strongly supports an early neurodevelopmental component to schizophrenia.
Intensive Remodeling of Purkinje Cell Spines after Climbing Fibers Deafferentation Does Not Involve MAPK and Akt Activation
Authors: MILAŠIN JELENA M. , BUFFO ANNALISA , CARULLI DANIELA , STRATA PIERGIORGIO
Published: April 2007

Abstract:  Subtotal lesion of the inferior olive (IO) achieved by treating experimental animals with 3‐acetylpyridine (3AP) induces partial Purkinje cells (PCs) deafferentation that leads to PC hyperactivity and new spine formation. Coincidentally, the olivary terminals belonging to the few survived olivary neurons undergo an extensive collateral sprouting resulting in reinnervation of the neighboring denervated PCs.
We obtained chemical deafferentation of PCs in adult rats (body weight, 120–170 g; age, 35–40 days) by a single intraperitoneal injection of 3AP (65 mg/kg body weight), and as early as 3 days after 3AP treatment, important morphological changes could be observed on PCs.
Mitogen‐activated protein kinase (MAPK) cascades and more specifically extracellular signal‐regulated kinases 1/2 (ERK1/2) play a critical role in the signaling events underlying synaptic plasticity. For instance, long‐term depression (LTD) in the adult hippocampus and long‐term potentiation (LTP) in cerebellum both involve ERK activation. Since PCs deprived of their climbing fibers (CFs) afferents initiate an intensive remodeling of the spines and rapid recall of the remaining CFs, it prompted us to see whether the observed phenomena correlated with MAPK and Akt activation. Immunohistochemistry and Western blotting were done at various time points after 3AP application (from 24 h to 6 days), as the exact dynamics of CF loss is not precisely known. As judged by Western blotting, there was no increase of activated ERK in the cerebellum. However, immunohistochemistry revealed increased ERK phosphorylation in the “pinceaux” of basket cells in 3AP animals.Similarly, stress‐activated protein kinase (SAPK)/c‐Jun N‐terminal kinase (JNK), p38 MAPK, and Akt activation were also studied by means of Western blotting and immunohistochemistry. Upon 3AP treatment no changes in phosphorylation status could be seen in the different kinases subjected to analysis. Our results suggest that activation of MAPK and Akt cascades is not essential in this model of neuronal plasticity.
Immunomorphological Analysis of RAGE Receptor Expression and NF‐κB Activation in Tissue Samples from Normal and Degenerated Intervertebral Discs of Various Ages
Authors: NERLICH ANDREAS G. , BACHMEIER BEATRICE E. , SCHLEICHER ERWIN , ROHRBACH HELMUT , PAESOLD GUENTHER , BOOS NORBERT
Published: April 2007

Abstract:  We immunohistochemically investigated the pattern of RAGE expression and NFκB translocation into the nucleus in 43 complete cross‐sections of human lumbar intervertebral discs (neonatal—85 years) and compared this with the carboxymethyl‐lysine (CML) modification of proteins as a marker for oxidative stress. No significant expression of RAGE, no obvious activation of NF‐κB, and no deposition of CML‐modified proteins were seen in fetal, juvenile, and young adolescent discs (until age of 13 years). In adults, 25–50% of nucleus pulposus cells were labeled for RAGE and activated NF‐κB, which correlated well with the occurrence and extent of CML staining in the pericellular matrix. In the annulus fibrosus significantly lower values were seen than in the nucleus pulposus. In consequence, we provide evidence for activation of the NF‐κB system in intervertebral discs in vivo, which correlates with accumulated oxidative stress and increases in age and disc degeneration. Oxidative stress (as monitored by CML modifications) may lead to RAGE activation and NF‐κB translocation.
Amyloid Precursor Protein and Presenilin 1 Interaction Studied by FRET in Human H4 Cells
Authors: NIZZARI MARIO , VENEZIA VALENTINA , BIANCHINI PAOLO , CAORSI VALENTINA , DIASPRO ALBERTO , REPETTO EMANUELA , THELLUNG STEFANO , CORSARO ALESSANDRO , CARLO PIA , SCHETTINI GENNARO , FLORIO TULLIO , RUSSO CLAUDIO
Published: April 2007

Abstract:  The mayor pathologic hallmarks of Alzheimer's disease (AD) are senile plaque and neurofibrillary tangles. Senile plaque are primarily made up of deposits of amyloid‐β protein, a proteolytic product derived from the amyloid precursor protein (APP). APP is a transmembrane protein detected into the endoplasmic reticulum, in the Golgi apparatus, at the cell surface, recycled by endocytosis to endosomes, whose physiological function is unclear. Presenilins (PS), are a component of γ‐secretase complex that cleave α‐CTFs (carboxy‐terminal fragment), or β‐CTFs, leaving 40 or 42 amino acids amyloid‐β peptides and 58 or 56 amino acids intracellular domains (AICD)
. Where the amyloid‐β peptides is generated is not clear. The study of APP–PS interaction in specific cell compartments provides a good opportunity to light upon the molecular mechanisms regulating the activity of the “γ‐secretase complex,” and where β‐amyloid is generated. In our study we used a biophysical assay of protein proximity: fluorescence resonance energy transfer (FRET), that can provide information about molecular interactions when two proteins are in the close proximity (<10 nm), to examine the subcellular localization and interaction between APP and PS1 in human neuroglioma cells (H4). Confocal microscopic analysis reveals extensive colocalization in different cells' compartment, and centrosomal or microtubule organizing center (MTOC) localization of APP and PS1, but not necessarily a close molecular interaction. We used FRET to determine if APP and PS1 interact at the cell centrosome
. FRET data suggest a close interaction between APP and PS1 in subcellular compartments and at the centrosome of H4 cells. Using this approach we show that APP and PS1 are closely associated in the centrosomes of the H4 cell.
Intensive Dose-Dense Compared With High-Dose Adjuvant Chemotherapy for High-Risk Operable Breast Cancer: Southwest Oncology Group/Intergroup Study 9623
Authors: Moore Halle C.F. , Green Stephanie J. , Gralow Julie R. , Bearman Scott I. , Lew Danika , Barlow William E. , Hudis Clifford , Wolff Antonio C. , Ingle James N. , Chew Helen K. , Elias Anthony D. , Livingston Robert B. , Martino Silvana
Published: April 2007

Purpose

Southwest Oncology Group (SWOG)/Intergroup study 9623 was undertaken to compare treatment with an anthracycline-based adjuvant chemotherapy regimen followed by high-dose chemotherapy (HDC) with autologous hematopoietic progenitor cell support (AHPCS) with a modern dose-dense dose-escalated (nonstandard) regimen including both an anthracycline and a taxane.

Patients and Methods

Participants in this phase III randomized study had operable breast cancer involving four or more axillary lymph nodes and had completed mastectomy or breast-conserving surgery. Patients were randomly assigned to receive four cycles of doxorubicin and cyclophosphamide followed by HDC with AHPCS or to receive sequential dose-dense and dose-escalated chemotherapy with doxorubicin, paclitaxel, and cyclophosphamide. The primary end point of this study was disease-free survival (DFS).

Results

Among 536 eligible patients, there was no significant difference between the two arms for DFS or overall survival (OS). Estimated five-year DFS was 80% (95% CI, 76% to 85%) for dose-dense therapy and 75% (95% CI, 69% to 80%) for transplantation. Estimated 5-year OS was 88% (95% CI, 84% to 92%) for dose-dense therapy and 84% (95% CI, 79% to 88%) for transplantation.

Conclusion

There is no evidence that transplantation was superior to dose-dense dose-escalated therapy. Transplantation was associated with an increase in toxicity and a possibly inferior outcome, although the hazard ratios were not significantly different from 1.
Reversibility of pregnancy-induced changes in the superficial veins of the lower extremities
Authors: Pemble L
Published: April 2007

Objectives: To determine the change in long saphenous vein (LSV) area in early pregnancy and the reversal postpartum in comparison with non-pregnant control values.

Methods: Ultrasonography was used to determine the LSV areas at four different levels in the right and left legs of women in an erect position. The measurements from 69 nulliparous women were used to determine the non-pregnant baseline measurements for vein area. The vein areas were similarly measured from 39 primigravida women in early pregnancy and postpartum.

Results: There was no significant difference found between measurements obtained from the right and the left legs. Non-pregnant baseline measurements were less than either the early pregnancy, or postpartum measurements obtained from the primigravida women.

Conclusions: Physiological changes associated with early pregnancy induce dilation of the LSV, and the reversal postpartum is not complete with vein areas statistically larger than in the non-pregnant state.
Ranking US Army Generals of the 20th Century: A Group Decision-Making Application of the Analytic Hierarchy Process
Authors: Retchless Todd , Golden Bruce , Wasil Edward
Published: April 2007

The pantheon of 20th century US Army generals contains many great wartime commanders. Military historians have written about their leadership qualities but have not ranked the best generals. We asked 10 experts in US military history to evaluate seven generals—Omar Bradley, Dwight Eisenhower, Douglas MacArthur, George Marshall, George Patton, John Pershing, and Matthew Ridgway—using the analytic hierarchy process in a group setting. We developed a ratings hierarchy, and each participant scored each general. We combined individual pairwise comparisons using the geometric-mean method and a new method based on linear programming and obtained a clear, three-tier ranking of generals with George Marshall judged the best US Army general of the 20th century, closely followed by Dwight Eisenhower.
Digit ratio as an indicator of numeracy relative to literacy in 7‐year‐old British schoolchildren
Authors: Brosnan Mark J.
Published: April 2007

A great deal of recent research has focused upon the relationship between a hypothesized index of prenatal testosterone exposure, digit ratio and health, social and cognitive functioning. Many inconsistencies within the pattern of findings have been identified in the relationship between digit ratio and absolute levels of cognitive ability. Recent research has identified a relationship between digit ratio and basic numeric competency. This basic numerical competency has been argued to be influenced by biological factors. The present study extended this finding to academic assessment, namely the Standardized Assessment Tests undertaken in numeracy and literacy by children in the UK at the age of 7. The present study hypothesized that digit ratio would correlate with the relative difference between numeracy and literacy abilities. Digit ratios were calculated for 75 (mainly Caucasian) children aged between 6 and 7 attending a state funded infant school. The digit ratios were then correlated with the results from their National Standard Assessment Tests (SATs). A significant correlation was found as hypothesized. Additionally, there was a negative correlation between digit ratio and numeracy for males (indicating higher prenatal testosterone exposure related to higher numeracy SAT scores) and a positive correlation between digit ratio and literacy for females (indicating lower prenatal testosterone exposure related to higher literacy SAT scores). These effects were small and the implications for using digit ratio to facilitate understanding of hormonal influences upon academic attainment are discussed.
Morphological lattice models for the simulation of softwood failure and fracture
Authors: Fournier Christopher R. , Davids William G. , Nagy Edwin , Landis Eric N.
Published: April 2007

This paper details the development of morphological lattice models to simulate fracture and failure in softwood. The lattice models rationally incorporate growth-ring geometry, differences in strength and stiffness between earlywood and latewood, and variations observed in the grain direction of clear wood (grain perturbation). Details regarding the implementation of these features are presented. Grain perturbation is shown to be a significant contributor to strength and stiffness variability. Simulations demonstrate that the inclusion of growth-ring geometry and incorporation of differences in the mechanical properties of earlywood and latewood are necessary for the lattice models to predict realistic fracture paths. Results are presented for laboratory tests on small red spruce specimens loaded in parallel-to-grain tension and shear. The lattice models give good predictions of mean specimen stiffness and strength, and reasonable predictions of strength variability. The fracture paths predicted by the lattice models are in excellent agreement with the experimental observations.
Characterization and strength modeling of parallel-strand lumber
Authors: Clouston Peggi
Published: April 2007

The current work expands on a three-dimensional, non-linear, stochastic finite-element model previously developed by the author. The model predicts a materially non-linear stress-strain curve for tension, compression and bending scenarios. It is based on the non-linear constitutive properties of the individual strands, which are characterized within the framework of orthotropic elasto-plasticity. The constitutive model employs the Tsai-Wu yield criterion and an associated flow rule. Failure is marked by an upper bound surface whereupon either perfect plasticity or an abrupt loss of strength and stiffness ensues. The finite element code has also extended the capacity to perform Monte Carlo simulations. The model was further developed to predict the mechanical behavior of parallel-strand lumber (PSL) made from Douglas fir. The physical features of PSL were measured and incorporated into the finite element model and the mechanical behavior of PSL was simulated. Statistical distributions for macroporosity and grain angle variation in PSL were created and included in the model as individual random variables in a stochastic and probabilistic manner. Constitutive curves for PSL were numerically generated under tensile, compressive and three-point bending conditions. Comparison of the computed and experimental data sets demonstrates the validity of the proposed modeling technique.
Experimental and numerical investigation of wood fracture mechanisms at different humidity levels
Authors: Vasic Svetlana , Stanzl-Tschegg Stefanie
Published: April 2007

Differences in fracture patterns and properties at various moisture levels are experimentally and numerically evaluated and discussed. Experiments were performed on spruce, pine, oak and beech. The influence of moisture at 98%, 80%, 65% and 30% RH and the mechanisms involved were investigated for softwoods and hardwoods subjected to opening mode I fracture using in situ and ex situ real-time environmental scanning electron microscopy (ESEM). The wedge-splitting technique was employed. To quantify the effect of humidity, fracture toughness values were obtained from ex situ tests and finite element analysis of the contact problem in wedge-splitting. In addition, lattice fracture model simulations were performed for numerical investigation of the fracture mechanisms. Distinct changes in wood fracture behaviour were observed as a function of moisture content. Fracture toughness was highest at 30% RH for all species except for oak, and showed higher values in the radial-longitudinal than in the tangential-radial direction. In green wood, water droplets moved away from the cell lumens around the crack tip. Drying of wood promotes microcracking and crack bridging as toughening mechanisms. The findings reported may be useful for further research into the interaction between moisture transfer and stress gradients in wood accompanied by moisture-crack phenomena.
Le peuplement estival de cétacés dans le Sanctuaire Marin Pelagos (Méditerranée nord-occidentale): distribution et abondance / Summer cetacean popoulation in the Pelagos Marine Sanctuary (northwest Mediterranean): distribution and abundance
Authors: Gannier Alexandre
Published: April 2007

Une campagne à la mer de 10 jours a été menée durant l'été 2001 pour déterminer la population de cétacés dans le Sanctuaire Marin Pelagos de Méditerranée occidentale, grâce à la méthode du transect linéaire combinée à un échantillonnage acoustique. Un total de 1613 km d'effort effectif de prospection a permis d'obtenir 93 observations de cétacés de huit espèces différentes: le Dauphin bleu et blanc (55 observations), le Rorqual commun (25 observations), le Cachalot, le Dauphin de Risso, le Dauphin commun, le Ziphius de Cuvier, le Globicéphale noir et le Grand dauphin. Ces espèces ont été observées en fonction de leur habitat préferentiel dans quatre régions du Sanctuaire: les secteurs nord-est, central, sud-ouest et tyrrhénien. C'est dans le secteur central que les abondances maximales de Dauphin bleu et blanc et de Rorqual commun ont été rencontrées, mais une diversité plus forte a été trouvée dans le secteur tyrrhénien. L'estimation de densité pour ces deux espèces s'établit à 0,52 individus/km
Year-long stability and individual differences of male long calls in Japanese pikas Ochotona hyperborea yesoensis (Lagomorpha) / Stabilité annuelle et differences individuelles des cris d'appels longs des mâles de pikas du Japon Ochotona hyperborea yesoensis (Lagomorpha)
Authors: Kojima Nozomu , Onoyama Keiichi , Kawamichi Takeo
Published: April 2007

Long calls of three adult male Japanese pikas were tape-recorded in the Taisetsuzan National Park, Hokkaido, Japan, from July 1996 to July 1998. A long call consisted of 3–13 elements, each with a characteristic W-shaped wave. There was apparent individual variation in sonographic patterns and the fundamental frequencies. Such individual variation did not differ with animal age, or through the reproductive and non-reproductive seasons. The complicated structure of W-shaped waves may involve much information concerning individual difference, and the repetition of elements in the long call may advertise sexual activity, location, and territorial ownership to opponents and mates, based on individual identification only by hearing calls.
Distribution and relative abundance of giant squirrels and flying squirrels in Karnataka, India / Distribution et abondance relative des espèces d'écureuils géants et volants à Karnataka, Inde
Authors: Kumara Honnavalli N. , Singh Mewa
Published: April 2007

We assessed the distribution and relative abundance of giant squirrels and flying squirrels in the state of Karnataka, India. Two species of giant squirrels, the Indian giant squirrel and the grizzled giant squirrel, and two species of flying squirrel, the large brown flying squirrel and the small Travancore flying squirrel, were found to occur in Karnataka. Indian giant squirrels and large brown flying squirrels were more widely distributed than the other two species. The distributional range included the forests of the Western and Eastern Ghats. However, their distribution was confined only to forests with tall trees. Indian giant squirrels and large brown flying squirrels occur in both deciduous and evergreen forests. Small Travancore flying squirrels occupied high-rainfall evergreen forests on western slopes in the Western Ghats, and the grizzled giant squirrels occupy riverine forests. This report of the small Travancore flying squirrel is the first of this species from Karnataka, and this population is the most northern population of its distributional range. Hunting was found to be a major threat, and influenced the abundance of all species except the grizzled giant squirrel. Hunting was primarily for domestic consumption.
Systematic relationships of the Guianan brush-tailed rat (Isothrix sinnamariensis ) and its first occurrence in Guyana / Systématique du rat à queue en brosse de Guyane ( Isothrix sinnamariensis ) et première découverte en Guyane
Authors: Lim Burton K. , Engstrom Mark D. , Patton John C. , Bickham John W.
Published: April 2007

Isothrix sinnamariensis was originally described and known only from French Guiana. We document the first occurence of this species from Guyana. A single sub-adult male was collected in lowland tropical rainforest near the headwaters of the Essequibo River. Although smaller in external and cranial size than the two adult females of the type description, our third known specimen represents the basal lineage to the type-series clade, with an average sequence difference of 1.72% based on cytochrome b mitochondrial DNA sequences. However, the degree of morphological and genetic divergence (2.67%) between I. sinnamariensis and its sister taxon I. pagurus is substantially less than the chromosomal differences originally used to distinguish them as two separate species. In contrast, distinctive karyotypes, morphological differences, and higher levels of mtDNA divergence (13.48%) between the other two species recognized, I. negrensis that was recently separated from I. bistriata , suggest an earlier and deeper diversification for these taxa.
Population abundance of the common hippopotamus Hippopotamus amphibius in the Haut Niger National Park, Republic of Guinea / Abondance de la population d'hippopotame commun Hippopotamus amphibius dans le Parc National du Haut Niger, République de Guinée
Authors: Brugière David , Magassouba Bakary , Sylla Amidou , Diallo Halimou , Sow Mamadou
Published: April 2007

The Republic of Guinea is thought to contain the largest population of common hippopotamus in West Africa. However, no systematic field survey has been carried out recently and the information available is limited to informal observations. To clarify the status of the common hippopotamus in Guinea, we carried out a biannual population survey along the section of the Niger River (the largest river in Guinea) within the Haut Niger National Park. We counted 93 hippopotamuses in 28 groups in the dry season and 77 hippopotamuses in 23 groups in the wet season. Mean group size and number of neonates did not change between the seasons. Hippopotomuses were more numerous along the river sections bordering uncultivated floodplains. This underlines the significance of this habitat (which is used as a grazing area) for conservation of this species. Haut Niger National Park is the most important protected area in Guinea for conservation of the common hippopotamus. Hippopotamus-human and -cattle conflicts in terms of floodplain use in the park's buffer zone should be closely monitored. Floodplain conversion to rice fields represents one of the most important threats to the long-term conservation of hippopotamus populations in Guinea.
Mus spretus et M. musculus (Rodentia, Mammalia) en zone méditerranéenne: différenciation biométrique et morphologique: application à des fossiles marocains pléistocènes / Mus spretus and M. musculus (Rodentia, Mammalia) in the Mediterranean zone: biometric and morphological differentiation: application to Pleistocene Moroccan fossils
Authors: Darviche Djamchid , Orth Annie , Michaux Jacques
Published: April 2007

La présente étude porte sur la taille et la forme des dents et sur la morphologie crânienne d'individus en provenance d'Europe sud-occidentale et d'Afrique du Nord caractérisés génétiquement comme appartenant aux espèces Mus spretus et Mus musculus domesticus . Une révision des caractères diagnostiques des dents et du crâne utilisés pour la détermination de l'appartenance spécifique des spécimens a été faite. La révision porte sur 17 caractères métriques et 14 caractères morphologiques. Une application à un matériel fossile inédit d'âge pléistocène supérieur du Maroc a ensuite été tentée. La détermination de ces restes fossiles représentés par des molaires inférieures de souris du gisement de Doukkala II, près de Rabat, permet de conclure à la présence d'une souris très proche de l'actuelle M. spretus . La présence dans le Pléistocène supérieur d'une souris, différente de la souris domestique, est ainsi démontrée dans le nord de l'Afrique, l'arrivée de la souris domestique dans ce secteur restant à préciser.
Geographic variation in body size of American mink ( Mustela vison ) / Variation géographique de la taille du corps chez le vison d'Amérique ( Mustela vison )
Authors: Stevens Richard T. , Kennedy Michael L.
Published: April 2007

Spatial variation in 26 morphological characters of American mink ( Mustela vison ) from 35 localities in North America was investigated using univariate and multivariate statistical analyses. Localities were chosen based on watersheds, and it was hypothesized that high levels of gene flow in minks would prevent partitioning of body size variation within watersheds. All 26 characters in males and 25 of 26 in females exhibited significant interlocality variation. The patterns of variation in body size resulting from principal components analysis indicated that, for both sexes, minks were largest in Alaska, Manitoba, and Alberta; smallest minks were found in Florida and Quebec. There did not appear to be a relationship between body size and geographic proximity. Environmental factors collectively were found to be related to body size, although individual variables were not typically significant. Of 16 environmental variables examined, only longitude was correlated with body size in both sexes, with largest minks in the west and smallest in the east. Latitude was also correlated with body size in females. It was concluded that variation in body size of mink was likely the result of more than one factor that includes both biotic and abiotic features.
Randomized Clinical Trial of Prevention of Hydrocephalus After Intraventricular Hemorrhage in Preterm Infants: Brain-Washing Versus Tapping Fluid
Authors: Whitelaw Andrew , Evans David , Carter Michael , Thoresen Marianne , Wroblewska Jolanta , Mandera Marek , Swietlinski Janusz , Simpson Judith , Hajivassiliou Constantinos , Hunt Linda P. , Pople Ian
Published: April 2007

OBJECTIVE. Hydrocephalus is a serious complication of intraventricular hemorrhage in preterm infants, with adverse consequences from permanent ventriculoperitoneal shunt dependence. The development of hydrocephalus takes several weeks, but no clinical intervention has been shown to reduce shunt surgery in such infants. The aim of this study was to test a new treatment intended to prevent hydrocephalus and shunt dependence after intraventricular hemorrhage.

METHODS. We randomly assigned 70 preterm infants who had gestational ages of 24 to 34 weeks and were progressively enlarging their cerebral ventricles after intraventricular hemorrhage to either (1) drainage, irrigation, and fibrinolytic therapy to wash out blood and cytokines or (2) tapping of cerebrospinal fluid by reservoir as required to control excessive expansion and signs of pressure (standard treatment). We evaluated outcomes at 6 months of age or hospital discharge (if later).

RESULTS. Of 34 infants who were assigned to drainage, irrigation, and fibrinolytic therapy, 2 died and 13 underwent shunt surgery (dead or shunt: 44%). Of 36 infants who were assigned to standard therapy, 5 died and 14 underwent shunt surgery (dead or shunt: 50%). This difference was not significant. Twelve (35%) of 34 infants who received drainage, irrigation, and fibrinolytic therapy had secondary intraventricular hemorrhage compared with 3 (8%) of 36 in the standard group. Secondary intraventricular hemorrhage was associated with an increased risk for subsequent shunt surgery and more blood transfusions.

CONCLUSIONS. Despite its logical basis and encouraging pilot data, drainage, irrigation, and fibrinolytic therapy did not reduce shunt surgery or death when tested in a multicenter, randomized trial. Secondary intraventricular hemorrhage is a major factor that counteracts any possible therapeutic effect from washing out old blood.
Photocatalytic properties of MIn(WO4)2(M = Li, Na, and K)
Authors: Li Zhaosheng , Ye Jinhua , Zou Zhigang
Published: April 2007

MIn(WO4)2(M = Li, Na, and K) with InO6and WO6octahedra were synthesized via a conventional solid-state reaction method. The photophysical and photocatalytic properties were studied. Compared with WO3, which is unable to evolve H2from an aqueous CH3OH solution under illumination, the three materials can evolve H2and O2from aqueous solutions with CH3OH and AgNO3sacrificial reagents, respectively. The activity order of photocatalytic H2evolution is NaIn(WO4)2> LiIn(WO4)2> KIn(WO4)2under irradiation (λ > 200 nm). Under irradiation (λ > 300 nm), however, LiIn(WO4)2has a high activity for photocatalytic H2evolution over NaIn(WO4)2. It is also noteworthy that LiIn(WO4)2and NaIn(WO4)2exhibit the ability to split pure water. The results suggest that the bottoms of the conduction bands in these photocatalysts are raised to meet the potential requirements of photocatalytic H2evolution.
In situ synthesis of lithium ferrite nanoparticle/polymer hybrid
Authors: Hayashi Koichiro , Sakamoto Wataru , Yogo Toshinobu
Published: April 2007

Lithium ferrite particle/organic hybrid was synthesized in situ from iron–organic and lithium–organic compounds below 100 °C. Spinel ferrite particle/organic hybrid was synthesized by hydrolyzing a mixture of iron (III) 3-allylacetylacetonate (IAA) and lithium acrylate (LA). X-ray diffraction analysis revealed that the crystallinity of spinel particle was dependent on the polymerization treatment and the hydrolysis conditions. The saturation magnetization of hybrid increased with increasing methylhydrazine and water amount of hydrolysis. Nanocrystalline lithium ferrite particle about 5 nm was dispersed in the organic matrix. The hybrid showed neither remanence nor coercive force at room temperature. The magnetization versus field/temperatureH/Tcurves from 100 to 300 K were superimposed on the same curve and satisfied the Langevin equation. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curve revealed that the blocking temperature was about 75 K. The remanent magnetization and coercive field of the hybrid were 8.9 A·m2/kg and 26.3 kA/m, respectively, at 10 K.
Nanocrystalline gold and gold–palladium as effective catalysts for selective oxidation
Authors: Edwards Jennifer , Landon Philip , Carley Albert F. , Herzing Andrew A. , Watanabe Masashi , Kiely Christopher J. , Hutchings Graham J.
Published: April 2007

The recent interest in oxidation catalysis provides the focus for this article. Until recently, gold has been overlooked as a key component of both homogeneous and heterogeneous catalysts. However, the observation in the 1980s that nanocrystalline gold supported on oxides was an effective catalyst for low-temperature carbon monoxide oxidation has now captured the imagination of many researchers. At present, low-temperature carbon monoxide oxidation remains an intensely studied field, but in recent years increased emphasis has been placed on using gold catalysts for selective oxidation. For example, the oxidation of alkanes, alkenes, and alcohols have all been shown to be effective with gold-based catalysts. In addition gold–palladium bimetallic catalysts have been shown to be very effective for the direct formation of hydrogen peroxide, and this will be described in this article.
Role of nitrogen in the homoepitaxial growth on diamond anvils by microwave plasma chemical vapor deposition
Authors: Qiu Wei , Vohra Yogesh K. , Weir Samuel T.
Published: April 2007

The catalytic effect of nitrogen during the homoepitaxial diamond growth on a diamond anvil was investigated using isotopically enriched carbon-13 methane in a feed-gas mixture in a microwave plasma chemical vapor deposition reactor. The use of isotopically enriched carbon-13 allows us to precisely measure the film thickness in this homoepitaxial growth process by Raman spectroscopy. It is found that the addition of 0.4 sccm of nitrogen to an H2/CH4/O2 gas-phase mixture increases the growth rate by a factor of 2.3. This enhanced growth rate with the addition of trace amounts of nitrogen allows for a quick encapsulation of embedded sensors in the designer diamond anvils and is a key control parameter in the fabrication process. Photoluminescence spectroscopy reveals nitrogen-vacancy defect centers in the high-growth-rate diamonds. Atomic force microscopy reveals dramatic changes in the surface microstructure as is indicated by a total loss of step-flow growth morphology on the addition of nitrogen in the plasma.
Ferroelectric properties of heteroepitaxial PbTiO3 and PbZr1–xTixO3 films on Nb-doped SrTiO3 fabricated by hydrothermal epitaxy below Curie temperature
Authors: Han S.H. , Ahn W.S. , Lee H.C. , Choi S.K.
Published: April 2007

PbTiO3 (PTO) and PbZr1-xTixO3 (PZT) films on a (100) Nb-doped SrTiO3 (NSTO) substrate were fabricated at 160 and 210 °C, respectively, by hydrothermal epitaxy below the Curie temperature, TC. The PTO capacitor had a square hysteresis curve compared to the rounded hysteresis curve of the PZT capacitor. These differing behaviors in the polarization-electric hysteresis curves can be explained by the existence of an interfacial layer formed between the PZT film and the NSTO substrate. The PZT capacitor showed almost no polarization fatigue after 1011 switching cycles. However, the PTO capacitor revealed a slightly different fatigue behavior due to the microvoids that formed as a result of the agglomeration of the island growth mode. However, the fatigue behavior of both capacitors revealed that defects, such as the lead or oxygen vacancies, were suppressed by the hydrothermal epitaxy using a very low fabrication temperature below TC.
Large-area quantification of BaCeO3 formation during processing of metalorganic-deposition-derived YBCO films
Authors: Wesolowski D.E. , Cima M.J.
Published: April 2007

A method is described for the quantification of BaCeO3 formation during the growth of YBa2Cu3O7–x (YBCO) films on CeO2 buffer layers. The method is based on the selective etching of BaCeO3 followed by inductively coupled plasma (ICP) excitation spectroscopy. A 10% HNO3 solution, at room temperature, dissolved BaCeO3 and YBCO in minutes but did not significantly etch CeO2 films. ICP excitation spectroscopy was used to quantify the extent of the reaction over macroscopic areas of film (∼1 cm2). BaCeO3 peak areas were measured by x-ray diffraction (XRD) and calibrated to the ICP excitation spectroscopy results. XRD and ICP excitation spectroscopy results indicated that BaCeO3 formation through a metalorganic deposition (MOD)-derived CeO2 layer follows the parabolic growth law. Almost the entire ceria cap layer was consumed by the growth of BaCeO3 after 2 h at 760 °C in the MOD process examined. BaCeO3 growth was substantially slower at 725 °C; only 25 ± 3% of the ceria layer reacted.
Comments on “Further investigation on the definition of the representative strain in conical indentation” by Y. Cao and N. Huber [J. Mater. Res. 21, 1810 (2006)]: A systematic study on applying the representative strains to extract plastic properties through one conical indentation test
Authors: Ogasawara Nagahisa , Chiba Norimasa , Zhao Manhong , Chen Xi
Published: April 2007

Cao and Huber [J. Mater. Res., 21, 1810 (2006)] proposed parameter-dependent representative strains, which have the potential to measure plastic properties from one conical indentation test. However, the potential performance of such a technique was not systematically analyzed. In this commentary, through a comprehensive numerical investigation, it is found that the two basic variables in Cao and Huber’s formulation are not completely independent, and it is difficult to obtain the two independent (sufficiently separated) representative stress–strain points needed for determining the plastic properties. Consequently, systematic errors (which could well exceed 100%) are generated for a wide range of materials, and the results are quite sensitive to small perturbations. As a complementary and critical examination of the original article, this commentary suggests that it is unreliable to use the representative strains proposed by Cao and Huber [J. Mater. Res., 21, 1810 (2006)] to measure the material plastic properties from one indentation.
High-resolution x-ray topography of dislocations in 4H-SiC epilayers
Authors: Kamata Isaho , Tsuchida Hidekazu , Vetter William M. , Dudley Michael
Published: April 2007

Synchrotron x-ray topography with a high-resolution setup using 1128 reflection was carried out on 4H-SiC epilayers. Four different shapes of threading-edge dislocation according to Burgers vector direction were observed. The four types of threading-edge dislocation images were calculated by computer simulation, and the experimental results correlated well with the simulation results. The detailed topographic features generated by plural screw dislocations and basal plane dislocations were also investigated.
Energetics of rare-earth-doped hafnia
Authors: Simoncic Petra , Navrotsky Alexandra
Published: April 2007

The enthalpies of formation of rare-earth (RE)-doped Hf1−xRExO2−x/2 solid solutions (RE = Sm, Gd, Dy, Yb; x = 0.25 to 0.62) with respect to the oxide end members, monoclinic HfO2 and C-type REO1.5, were determined using oxide melt solution calorimetry. The enthalpies of formation fit a function quadratic in composition. The strongly negative interaction parameters in all solid solutions confirm a strong tendency for short-range order. Though strongly negative for all systems, the interaction parameters become less negative with increasing ionic potential (decreasing RE radius). Crystallization energetics were investigated for amorphous coprecipitation products with x = 0.4. The energy difference between the crystalline (fluorite and pyrochlore) and amorphous phases decreases with decreasing dopant radius. This suggests that systems doped with small RE ions have more similar local structures in the fluorite and amorphous phases. These observations may result in a smaller kinetic barrier to recrystallization and account for the greater radiation resistance of materials with smaller RE cations.
Fracture size effect in ultrananocrystalline diamond: Applicability of Weibull theory
Authors: Peng B. , Li C. , Moldovan N. , Espinosa H.D. , Xiao X. , Auciello O. , Carlisle J.A.
Published: April 2007

An analysis of size effects and doping on the strength of ultrananocrystalline diamond (UNCD) thin films is presented. The doping was achieved by the addition of nitrogen gas to the Ar/CH4microwave plasma. The strength data, obtained by means of the membrane deflection experiment (MDE) were interpreted using Weibull statistics. The validity and predictive capability of the theory were examined in conjunction with detailed fractographic and transmission electron microscopy microstructural analysis. The Weibull parameters were estimated nonlinear regression based on 480 tests when the specimen volume varied from 500 to 16,000 μm3. Both undoped and doped UNCD films exhibited a decrease in strength with an increase in specimen size. A significant drop in strength was measured when the films were doped with nitrogen. Such a drop was almost independent of the percentage of doping. The results also showed that one can predict the fracture strength of a component possessing any arbitrary volume to within ±3%. Moreover, the failure mode of UNCD was found to be volume controlled. We also report changes in Young’s modulus as a function of doping forn-doped UNCD thin films.
Inheriting morphology and photoluminescence properties of MgO nanoplates
Authors: Qiu Xiaoqing , Li Guangshe , Li Liping
Published: April 2007

This work reports on a new morphology-inheriting methodology to MgO nanoplates. Precursor of Mg(OH)2 nanoplates was synthesized by a solvothermal method and showed a hexagonal shape. The morphological features of Mg(OH)2 nanoplates were retained to the resulting MgO nanoplates using a programmed heating process. MgO nanoplates showed highly hydroxylated surfaces. Upon excitation, the interactions between hydroxyl groups and surface O2−4c and O2−3c species gave rise to a dominant ultraviolet emission at 415 nm.