bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of Food Frequency Questionnaire for Assessing Dietary Macronutrients and Calcium Intake in Italian Children and Adolescents
Authors: Bertoli Simona , Petroni Maria Letizia , Pagliato Emanuela , Mora Stefano , Weber Giovanna , Chiumello Giuseppe , Testolin Giulio
Published: April 2005

Objectives:

To validate a food frequency questionnaire to determine calcium and macronutrient intake in healthy children and adolescents.

Materials and Methods:

The questionnaire consisted of 16 main food groups containing the main foods composing the diet of Italian children, a total of 136 items and 23 questions about food habits, supplements and servings. Color photographs to identify serving size were included. The questionnaire was validated by comparing it with the 7‐day weighed record method in 37 healthy volunteers in two different age groups: children aged 6 ‐ 10 years (n = 18) and adolescents aged 16 ‐ 20 years (n = 19).

Results:

The food frequency questionnaire seemed to overestimate the nutrient intake when compared with 7‐day weighed records; however the two methods were highly correlated for all the nutrients considered. The range of Pearson's correlations between energy and nutrient intake (protein, fat, carbohydrates and calcium) determined from food frequency questionnaire and 7‐day weighed record were 0.5‐0.6 in children and 0.5‐0.8 in young adults. Agreement between the two methods in classifying relative intakes was examined by determining the frequency of similar classification into terciles. Two thirds of the subjects were correctly classified for most nutrients, with a very low (2% to 5%) percentage of grossly misclassifications.

Discussion:

The food frequency questionnaire has proved adequate to rank a pediatric population in terms of calcium and macronutrient intakes. The ranking of subjects is extremely useful for epidemiologic studies evaluating the relation between nutrient intake and disease.
Treatment Regimens for Helicobacter pylori Infection in Children: Is In Vitro Susceptibility Testing Helpful?
Authors: Faber Joseph , Bar‐Meir Maskit , Rudensky Bernard , Schlesinger Yechiel , Rachman Elena , Benenson Shmuel , Sirota Gisela , Stankiewic Halina , Halle David , Wilschanski Michael
Published: April 2005

Background:

Treatment regimens for Helicobacter pylori have variable success rates, and data comparing effectiveness with respect to strain sensitivity are relatively scarce.

Objective:

To evaluate the efficacy of two treatment regimens for eradication of H. pylori and the impact of bacterial susceptibility testing.

Study Design:

265 children endoscopically diagnosed with H. pylori infection were randomly assigned to receive omeprazole + amoxicillin with clarithromycin or omeprazole + amoxicillin with metronidazole. Bacterial culture and susceptibility was performed in a subgroup. Eradication was assessed by 13C‐urea breath test.

Results:

Eradication was achieved in 73.4% by omeprazole + amoxicillin with metronidazole and in 62.6% by omeprazole + amoxicillin with clarithromycin (P = 0.078). H. pylori was cultured successfully in 105 patients. Resistance to metronidazole was detected in 31.4% of the isolates and resistance to clarithromycin in 15%. Eradication rate by omeprazole + amoxicillin with metronidazole for metronidazole‐susceptible bacteria (N = 38) was 90%, and for resistant bacteria (N = 19) it was 42%. Only 75% of clarithromycin‐sensitive strains were successfully treated by omeprazole + amoxicillin with clarithromycin, and none of the cases with clarithromycin‐resistant strains responded to omeprazole + amoxicillin with clarithromycin treatment.

Conclusion:

There is a trend of greater efficacy of eradication with omeprazole + amoxicillin with metronidazole versus omeprazole + amoxicillin with clarithromycin therapy. Although resistance negatively influences eradication, first‐line sensitivity‐based treatment would be expected to improve this rate only slightly. Susceptibility testing should probably be reserved only for treatment failures.
Long‐Term Outcome of Intractable Ulcerating Enterocolitis of Infancy
Authors: Thapar Nikhil , Shah Neil , Ramsay Alan D , Lindley Keith J , Milla Peter J
Published: April 2005

Background:

Chronic enterocolitis is rare in infancy and accounts for less than 0.5% of all newly diagnosed inflammatory bowel disease (IBD) in the UK. Presentation at this young age is usually indicative of underlying immunodeficiency/immunodysregulation. A group of such infants suffer intractable ulcerating enterocolitis of infancy (IE) in which there is a pan‐enteritis with marked oro‐anal involvement and deep flask like mucosal ulcers throughout the colon.

Methods:

Retrospective review of presenting features, treatment and long‐term outcome in a series of 8 children with typical IE.

Results:

The 8 children were aged between 1 and 4 weeks at onset (median 2 weeks, mean 2.3 weeks), of which 7 were followed up for 2‐22 years (median 7.5 years, mean 11 years). All 8 children had an intractable disease course requiring a colectomy for control of symptoms. The median age at colectomy was 1.7 years (range 4 months‐4 years). Three children developed a generalised lymphadenopathy due to uncontrolled EBV‐related lymphoid proliferations (ages 4, 12, 18). These comprised a monomorphous B‐lymphoycte lympho‐proliferative disorder, a large pleomorphic follicular lymphoma, and a high grade pleomorphic B cell non‐Hodgkin's lymphoma.

Conclusions:

Infants with IE have a high risk of developing lymphomatous proliferations that appears to be related to the underlying immunodysregulation. Use of aggressive immunosuppression and acquisition of EBV infection appears to accelerate this process; hence we advocate early colectomy in confirmed cases. In children with IE screening for EBV and vigilance for abnormal lymphoid proliferations is paramount.
Overweight Children and Adolescents: A Clinical Report of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition
Authors: Baker Susan , Barlow Sarah , Cochran William , Fuchs George , Klish William , Krebs Nancy , Strauss Richard , Tershakovec Andrew , Udall John
Published: April 2005

Childhood overweight and obesity are major health problems with immediate and long‐term consequences of staggering magnitude. Despite this, there are few preventive and therapeutic strategies of proven effectiveness available to public health and clinical practitioners. Accruing such evidence is currently and appropriately a health policy priority, but there is an urgent need to intervene even before comprehensive solutions are fully established. The aim of this Clinical Report on Overweight Children and Adolescents is to present information on current understanding of pathogenesis and treatment of overweight and obesity. We report on the epidemiology, molecular biology and medical conditions associated with overweight; on dietary, exercise, behavioral, pharmacological and surgical treatments; and on the primary prevention of overweight in children and adolescents.
Lexical Repetition in Second Language Learners’ Peer Play Interaction
Authors: Rydland Veslemøy , Aukrust Vibeke Grøver
Published: April 2005

Recent studies have pointed to the importance of second language learners’ use of repetition for conversational participation and language learning. This study researched the significance of repetition, varying in type and complexity, for second language learning children's verbal participation in play as well as their academic language skills and extended discourse participation. Twenty‐seven 4‐ and 5‐year‐old children with Turkish as their first and Norwegian as their second language were videotaped in multiparty preschool play. The target children's second language lexical repetition of self and others was identified and subcategorized according to repetition complexity. The main findings suggested that self‐repetition was related to frequency of verbal participation, whereas complex other‐repetition was related to children's academic language skills and participation in extended discourse.
Screening for Nutritional Risk in Community‐Dwelling Old‐Old
Authors: Callen Bonnie L. , Wells Thelma J.
Published: April 2005

Abstract  Screening tools for detecting declining nutrition in community‐dwelling old‐old are few and problematic. The purpose of this study was to identify the leading risk factors associated with noninvasive measures of poor nutritional status among elders aged 80 or older still living independently in the community. This cross‐sectional descriptive study included 68 community‐dwelling old‐old (average age 85.7). Participants were recruited by parish nurses. In‐home interviews were conducted. Relationships between five well‐established measures of nutritional risk factors and two measures of nutritional status, body mass index (BMI) categories, and unintentional weight loss were examined. Depression and the food pyramid groups with adequate amounts eaten were predictive of unintentional weight loss in the previous 6 months (p = 0.013) but not of high or low BMI. In this sample, 25% were obese. Screening for depression and food intake may be useful in predicting nutritional decline among community‐dwelling old‐old and point to targeted interventions in a population who are large users of health care dollars.
The Public Health Nursing Role in Rural Japan
Authors: Yamashita Mineko , Miyaji Fumiko , Akimoto Reiko
Published: April 2005

ABSTRACT  The objective of this study was to describe the activities of the public health nurses in the local community. The setting was a small rural town in central Japan. The design was a descriptive study based on informant interviews supplemented by participant observation. The sample consisted of five public health nurses, four health care workers in other fields, and seven clients, all living in the same town. Each participant was interviewed individually. Interviews focused on the participants' understanding of what public health nurses actually do. Semistructured interview guides for each group of participants served as a framework to elicit participants' views on the activities of the public health nurses. Analysis of interview transcripts indicated that commitment was a core concept in the role of the public health nurses. Linked to this central theme were three constructs describing their work: identifying the real needs of clients, responding appropriately and promptly, and establishing trust relationships. The interviews indicated considerable public support for collaborative activities involving public health nurses, other health care workers, and community members. Implications for public health nurses' expanded role in Japan in relation to other health care professionals are addressed.
Beverly C. Flynn, an Oral History with a 20th Century Activist
Authors: Knollmueller Ruth N. , Abrams Sarah E.
Published: April 2005

Abstract  Beverly Collora Flynn, Ph.D., R.N., F.A.A.N., when asked what she believes her legacies will be, cites achievements that have sustained her professionally and personally. Through her work in the Institute of Action Research for Community Health at Indiana University School of Nursing and her work in Healthy Cities, she further developed the application of primary health care and community health promotion concepts into practice. A theme that emerges from her story is that of recognizing new approaches to meeting the health needs of communities and developing them into lasting practices. Flynn's long marriage to Pat and rich family life, including two children Bryan and Nicole have been balanced with her professional commitments and have been a source of strength for her as a person and as a nurse. Dr. Flynn is one of those exceptional individuals we honor, by telling her story as she told it to us in July, 2004 for this series on outstanding public/community health nursing leaders of the twentieth century.
Hydrothermal Precipitation of Lead Zirconate Titanate Solid Solutions: Thermodynamic Modeling and Experimental Synthesis
Authors: Lencka Malgorzata M. , Anderko Andrzej , Riman Richard E.
Published: April 2005

A previously developed thermodynamic model of hydro‐thermal synthesis of ceramic powders has been extended to include cases when solid solutions are formed. The model has been applied to the synthesis of a series of lead titanate zirconate solid solutions PbZrxTi1–xO3(PZT, 0.46 <x≤ 0.75). It predicts the optimum conditions (i.e., reagent, concentration, pH, and temperature) for the precipitation of phase‐pure homogeneous PZT, provided that the reactants are well mixed. The predictions have been experimentally corroborated using coprecipitated hydrous oxide ZrxTi1–xC2nH2O (0.46 <x≤ 0.75), as a precursor for Ti and Zr and water‐soluble lead acetate or nitrate salts as a source for Pb. When mixtures of hydrous oxides ZrO2·nH2O and TiO2·nH2O were employed as Ti and Zr precursors, independent PbTiO3and PbZrO3precipitates rather than the PZT solid solutions formed. These results can be rationalized on the basis of reaction kinetics where thermodynamic modeling includes or excludes the possibility of solid‐solution formation.
Relationship between Microstructure, Toughening Mechanisms, and Fracture Toughness of Reinforced Silicon Nitride Ceramics
Authors: Šajgalik Pavol , Dusza J. , Hoffmann M. J.
Published: April 2005

Different microstructures in Si3N4 ceramics containing Y2O3and Al2O3 as sintering additives were prepared by two‐step sintering. Pull‐out and elastic bridging were most frequently observed as the toughening mechanisms in samples with fine‐grained microstructures having needlelike β‐Si3N4grains with diameters of <1 μm. Crack deflection was the main toughening mechanism observed in samples with coarse‐grained microstructures having grains with diameters of >1 μm. The values of fracture toughness were varied from 6.1 to 8.2 MPa·m1/2 with respect to the microstructural characteristics, characterized by the volume fraction of needlelike grains and their diameter.
Sintering ZrO2/TiC Composites with TiH2: The Role of Transient Liquid Phase and of Substoichiometry
Authors: Krell Andreas , Blank Paul , Pippel Eckhard , Woltersdorf Jörg
Published: April 2005

Sintering tetragonal ZrO2with 35 vol% TiC results in a microstructure where all grain facets are free of amorphous interfaces independent of sintering aids as TiH2or MgO/ Y2O3; grain sizes are below 1 μm. With substoichiometric TiC1‐x, a relative density of 95% and closed porosity are obtained at a lower sintering temperature than with stoichiometric TiC, but subsequent cladless hot isostatic pressing (HIP) is required to achieve 99% density. High densities of 98% accompanied by good mechanical properties become possible by pressureless sintering with the use of TiH2. MgO/Y2O3doping also promotes densification, but results in less transformable zirconia and increases the number and size of amorphous triple junctions. The consequences are a lower fracture toughness and strength.
Barium Aluminosilicate Reinforced In Situ with Silicon Nitride
Authors: Richardson Kerry K. , Freitag Doug W. , Hunn David L.
Published: April 2005

Advanced ceramic composite materials that exhibit high strength and toughness with good thermal shock resistance are needed for emerging high‐temperature engineering applications. A recently developed in situ reinforced barium aluminosilicate glass‐ceramic shows promise of meeting many of the requirements for these types of applications with the added benefit of low‐cost fabrication through densification by pressureless sintering. The material is toughened through in situ growth of rodlike β‐Si3N4 grains resulting from the α–β silicon nitride phase transformation. Microstructural development and material properties for temperatures up to 1400°C are discussed. When compared to monolithic barium aluminosilicate, barium aluminosilicate reinforced with 70% by volume of Si3N4 shows a significant increase in flexural strength (from 80 to 565 MPa) and fracture toughness (from 1.8 to 5.74 MPa·m1/2) with a high resistance to thermal shock.
Microstructure Effects in Multidipped Tin Oxide Films
Authors: Park Sung‐Soon , Mackenzie John Douglas
Published: April 2005

Porous ultrafine tin oxide films (particle size 70–90 Å) have been prepared from tin alkoxide by dip coating. The influence of the number of coating applications on the thickness, microstructure, and electrical properties of multidipped tin oxide films was investigated. With an increase in the number of coating applications, the porosity of the multidipped films decreased from 60% to 12%, but the particle size of the films increased. The resistivity of the films decreased from 5.5 × 10–2 to 5.7 × 10–3Ω·cm with increasing the number of coating applications from 1 to 10. This tendency of the resistivity to decrease is due to the microstructural change of the films with the number of coating applications. The microstructure, the surface structure, and the composition of the multidipped films were investigated by scanning electron microscopy (SEM), X‐ray diffraction (XRD), and Auger electron spectroscopy (AES).
Mechanical Behavior of Alumina Reinforced with Carbon‐Coated Silicon Carbide Whiskers
Authors: Steyer Todd E. , Faber K. T.
Published: April 2005

SiC whiskers with 0, 20, and 50 Å carbon coatings were incorporated into an alumina matrix to modify residual thermal stress and interfacial bonding. Composites were characterized using triaxial X‐ray diffraction for residual stress determination and electron microscopy to explore interfacial chemistry. Fracture toughness and R‐curve behavior were examined for short and long crack lengths. Uncoated SiC whiskers optimized strength, fracture toughness, and R‐curve behavior of these composites. A graphite interphase at the whisker/matrix interface decreased contributions to crack bridging without promoting additional toughening by whisker pullout.
Studies on Abrasive Wear of Monolithic Silicon Nitride and a Silicon Carbide Whisker‐Reinforced Silicon Nitride Composite
Authors: Wang Dongfang , Mao Zhiyuan
Published: April 2005

Results presented in this paper demonstrate the roles of the most important parameters that govern abrasive wear of experimental ceramics. SEM studies of the abraded surfaces evidenced two main kinds of failures: microdropping of grain(s) and powder‐type wear track(s) resulting from the brittle microfracturing of parts of grain(s). There were whiskers in the surface, and whisker pullouts occurring during wear processes are believed to be the reasons for the lower wear rates of SiCw/Si3N4 composite ceramics under experimental conditions.
Nonequilibrium Phase Formation in Oxides Prepared at Low Temperature: Fergusonite‐Related Phases
Authors: Mather Scott A. , Davies Peter K.
Published: April 2005

Sol–gel methods have been developed to prepare YNbO4, YTaO4, and other rare‐earth niobates and tantalates with fergusonite‐related crystal structures. At low temperatures, all of the fergusonites, with the exception of SmTaO4, crystallize in a metastable tetragonal (T′) structure similar to that of tetragonal zirconia. Although all of the equilibrium forms of these oxides adopt a crystal structure containing an ordered distribution of the trivalent and pentavalent cations, a random cation distribution is obtained in the metastable T’phase. Metastable phase formation is often ascribed solely to kinetically limited topotactic crystallization. However, the changes in the grain size and unit‐cell volumes that accompany the metastable‐to‐equilibrium fergusonite conversions imply that other physical phenomena induced by small‐particle synthesis, namely the Gibbs‐Thompson pressure effect and the increased contribution of surface energy, cannot be ignored.
Effects of Stearic Acid on the Injection Molding of Alumina
Authors: Chan Tien‐Yin , Lin Shun‐Tian
Published: April 2005

This research investigated the influence of stearic acid on the injection molding of alumina, by varying the concentration of stearic acid. The interaction between stearic acid and alumina was identified using transmission infrared spectroscopy, indicating stearic acid preferentially adsorbed onto the alumina powder surface. In addition to slightly modifying the intrinsic binder viscosity, stearic acid adsorbed onto the powder surface changed the flow behavior of the mixtures from dilatant flow to pseudoplastic flow at low temperatures. As a result, inhomogeneous distribution of binder in the injection‐molded parts was minimized with increased stearic acid concentration. However, the possibility of forming bubbles in the mixtures arising from vaporization of stearic acid was enhanced. Additionally, the binder burnout temperature range was broadened with the increase of stearic acid concentration.
Effect of Lead Loss and Sheath Structure on Phase Formation and Alignment in (Bi,Pb)2Sr2Ca2Cu3O10+δ/Ag Composite Conductors
Authors: Luo Jian Shu , Merchant Nazarali , Maroni Victor A. , Dorris Stephen E. , Lanagan Michael T. , Tani Benjamin S.
Published: April 2005

The effects of metallic constituent evaporation and sheath structure on grain growth and alignment in silver‐sheathed (Bi,Pb)2Sr2Ca2Cu3O10+δ (Bi‐2223)/Ag composites have been investigated by inductively coupled plasma/atomic emission spectroscopy (ICP/AES), X‐ray diffraction, scanning electron microscopy, and energy dispersive X‐ray spectroscopy. Specimens of Bi‐2223/Ag composites fabricated by the oxide‐powder‐in‐tube technique were peeled (opened) lengthwise to expose the ceramic powder core, and then heat‐treated in 0.075 atm of oxygen for selected temperatures and times. The results were compared with those for as‐processed samples with closed silver sheaths treated under identical conditions. ICP/AES analysis indicated that lead was the only metallic element to undergo substantial evaporation during annealing of opened samples. The lead‐release process in parallel with the Bi‐2223 formation reaction had an activation energy of ∼25 kJ/mol. Lead loss from the opened samples resulted in incomplete conversion to Bi‐2223. The combined results show that the silver sheath effectively prevents evaporative lead loss, preserves and promotes densification, and induces texturing of the layered phases.
Tensile and Shear Properties of Continuous Fiber‐Reinforced SiC/Al2O3 Composites Processed by Melt Oxidation
Authors: Heredia Fernando E. , Evans Anthony G. , Andersson Clarence A.
Published: April 2005

The mechanical properties of a fiber‐reinforced SiC/Al2O3composite have been investigated in tension and shear. The material is shown to have class II characteristics (a “matrix dominated” ceramic matrix composite) with appreciable inelastic strain prior to failure. This strain is associated with matrix cracking accompanied by interface debonding and sliding. One consequence of this strain is the ability to redistribute stress, resulting in tensile notch insensitivity. Evaluation of the interface properties from hysteresis measurements has indicated an interface slip resistance similar to that for SiC/CAS and debond behavior similar to that for SiC/SiC. The consequence is the occurrence of inelastic deformation at stress levels intermediate between those found for these other composites. The SiC/Al2O3 has a relatively low initial modulus, because of cracking in the matrix‐only regions of the composite, caused by the thermal expansion mismatch between Al2O3 and SiC. The ultimate tensile strength is consistent with global load‐sharing requirements.
Fabrication and Characterization of Three‐Dimensional Carbon Fiber Reinforced Silicon Carbide and Silicon Nitride Composites
Authors: Nakano Kikuo , Kamiya Akira , Nishino Yoichi , Imura Toru , Chou Tsu‐Wei
Published: April 2005

Three‐dimensional (3D) carbon fiber reinforced SiC and Si3N4 composites have been fabricated using repeated infiltration of an organosilicon slurry under vacuum and pressure. Open porosity of the infiltrated body was reduced from 40% after the first infiltration to approximately 8% after the seventh cycle. Further reduction of open porosity to less than 3% was accomplished by hot‐press densification. The maximum values of flexural strength and fracture toughness were, respectively, 260 MPa and 7.3 MPa·m1/2for C/Si3N4 composites, and 185 MPa and 6 MPa·m1/2 for C/SiC composite.
TiN‐TiB2 Composites Prepared by Reactive Hot Pressing and Effects of Ni Addition
Authors: Zhang Guojun , Jin Zongzhe , Yue Xuemei
Published: April 2005

Using TiH2 and BN as raw materials, the reaction process of TiH2 and BN in the temperature range 1000°‐1600°C was studied. Then TiN‐TiB2 composites were prepared by reactive hot pressing. The effects of Ni addition on the sinterability and the mechanical properties of the composites were discussed. A composite containing 1 wt% Ni exhibited a bending strength of 614 MPa, fracture toughness of 6.20 MPa·m1/2, and Vickers hardness of 20.5 GPa.
Carbon Determination in Small Amounts of Ceramic Powder by Coulombic Titration
Authors: Hirakata Keigo , Rhine Wendell E. , Cima Michael J.
Published: April 2005

A new method for carbon determination in small samples was demonstrated. This method involves coulometric titration of an oxygen titrant through a solid‐electrolyte (yttria‐stabilized zirconia) tube. Oxygen is electrolytically introduced to a sealed sample chamber, and the partial pressure of oxygen is monitored as more oxygen is pumped. The point at which the oxygen partial pressure begins to rise is the end point. The method can accurately determine microgram quantities of carbon in 15‐mg samples. This method can determine microgram quantities of carbon and is, therefore, more sensitive than conventional combustion analysis. This method is ideal for investigating the carbon content of individual small electrical ceramic parts, such as multilayer ceramic capacitors.
Strength Measurements of Monolithic SiC and A12O3/SiC Composites after Exposure to Coal Slag
Authors: Breder Kristin , Tennery Victor J. , Strobel Tina M. , Hurley John E , Holowczak John E.
Published: April 2005

Four Si‐based ceramics—siliconized SiC (Si‐SiC), sintered α‐SiC, and two grades of SiC‐particulate‐reinforced A12O3—were exposed to a typical western coal ash with high calcium content (Wyodak) and a typical eastern coal ash rich in iron (Illinois #6) at two temperatures for 300 h in a muffle furnace. After exposure, the coupons were cut into flexure bars and remaining strength was measured in four‐point flexure at room temperature. The residual strength was compared to the as‐received strength, and the fracture originating flaws were identified. The standard grade of the particulate‐reinforced A12O3 showed no corrosive attack under any of the exposure conditions, and a slight strength reduction was attributed to aging effects. The three other materials showed varying degrees of strength reduction, with corresponding fracture‐initiating flaws being pits produced during the exposure. A general trend was that the eastern coal seemed to cause more corrosion than the western, and that 1260°C was a harsher exposure condition than 1093°C.
High‐Resolution Transmission Electron Microscopy of Transformed Magnesia‐Partially‐Stabilized Zirconia Precipitates
Authors: Wauchope Corinna J. , Kelly Patrick M.
Published: April 2005

Transformed Mg‐PSZ precipitates consist of monoclinic bands that are twin‐related across either (100)m or (001)mplanes in an arrangement that leads to accommodation of the shear component of the transformation shape strain. High‐resolution images of these variants reveal these twin relationships quite clearly. It is shown that complete compensation of shear does not always occur. This paper also shows observations of monoclinic variants related by a rotation of 90° around the normal to (001)m, in addition to those related by a 180° rotation for the twin‐related variants. These findings conform to the predictions of martensite theory and their implications are discussed in terms of shear compensation and reduction in overall strain energy.
Enhanced Dispersion Frequency of Hot‐Pressed Z‐Type Magnetoplumbite Ferrite with the Composition 2CoO·3Ba0.5Sr0.5O·10.8Fe2O3
Authors: Kimura Osamu , Matsumoto Masafumi , Sakakura Mitsuo
Published: April 2005

The high‐frequency magnetic properties of strontium‐partially‐substituted Z‐type magnetoplumbite with the composition 2CoO·3Ba1‐x.SrxO.yFe2O3 were studied using a hot‐pressing technique. The best properties were obtained for a sample hot‐pressed in oxygen, having x and y values of 0.5 and 10.8, respectively. The resonant frequency of that sample, corresponding to a μ” maximum reaching 2.5 GHz, was significantly larger than the value of 1.4 GHz previously reported for unsubstituted Z with the composition 2CoO·3BaO·12Fe2O3. This result implies that a new ferrite material, applicable in the gigahertz region, has been obtained.
Removing Hydroxypropyl Methylcellulose Sizing from Sapphire Fibers by Ultraviolet/Ozone Cleaning
Authors: Jayne Douglas T. , Matthiesen Mary M.
Published: April 2005

Ceramic‐fiber‐reinforced metallic and intermetallic matrix composites require well‐characterized fiber/matrix interfaces. These interfaces require that the fiber surface be clean prior to the formation of a composite or application of a fiber coating. This work investigates the effectiveness of ultraviolet (UV)/ozone exposure at removing hydroxypropyl methylcellulose sizing from sapphire plates and fibers. The surface cleanliness was characterized using X‐ray photoelectron spectroscopy (XPS). It was found that UV/ozone exposure removed the hydroxypropyl methyl‐cellulose sizing from the plates and fibers but did not remove inorganic species contained in the coating or on the sapphire surface. These inorganic species were readily removed with a water/methanol rinse, providing a clean sapphire surface for incorporation into a composite.
International multicentre trial protocol to assess the efficacy and safety of tenecteplase during cardiopulmonary resuscitation in patients with out‐of‐hospital cardiac arrest: The Thrombolysis in Cardiac Arrest (TROICA) Study
Authors: Spöhr F. , Arntz H. R. , Bluhmki E. , Bode C. , Carli P. , Chamberlain D. , Danays T. , Poth J. , Skamira C. , Wenzel V. , Böttiger B. W.
Published: April 2005

Prehospital cardiac arrest has been associated with a very poor prognosis. Acute myocardial infarction and massive pulmonary embolism are the underlying causes of out‐of‐hospital cardiac arrest in 50–70% of patients. Although fibrinolysis is an effective treatment strategy for both myocardial infarction and pulmonary embolism, clinical experience for this therapy performed during resuscitation has been limited owing to the anticipated risk of severe bleeding complications. The TROICA study is planned as one of the largest randomized, double‐blind, placebo‐controlled trials to assess the efficacy and safety of prehospital thrombolytic therapy in cardiac arrest of presumed cardiac origin. Approximately 1000 patients with cardiac arrest will be randomized at approximately 60 international study centres to receive either a weight‐adjusted dose of tenecteplase or placebo after the first dose of a vasopressor. Patients can be included if they are at least 18 years, presenting with a witnessed cardiac arrest of presumed cardiac origin, and if either basic life support had started within 10 min of onset and had been performed up to 10 min or advanced life support is started within 10 min of onset of cardiac arrest. Primary endpoint of the study is the 30‐day survival rate, and the coprimary endpoint is hospital admission. Secondary endpoints are the return of spontaneous circulation (ROSC), survival after 24 h, survival to hospital discharge, and neurological performance. Safety endpoints include major bleeding complications and symptomatic intracranial haemorrhage.
Antithrombotic effect of a new nitric oxide donor (LA419) on experimental thrombogenesis
Authors: Hernandez M. R. , Tonda R. , Arderiu G. , Pino M. , Serradell M. , Escolar G.
Published: April 2005

Background  The ability of nitrous compounds to donate nitric oxide (NO), an agent with vasodilating and inhibitory effects on platelet function, has been considered a useful pharmacologic strategy for cardiovascular complications. The purpose of this study was to investigate the effects of a new NO donor, LA419, on platelet interaction in an ex vivo model with human blood circulating through collagen‐rich surfaces.

Materials and methods  Platelet adhesive and cohesive function were analyzed by morphometric procedures after perfusion techniques. Treated blood was exposed to thrombogenic surfaces and platelet interactions were morphometrically evaluated.

Results  All the concentrations studied of LA419 (10 µM, 20 µM and 100 µM) reduced overall platelet interaction with a collagen surface (27·19 ± 4·72; 25·52 ± 3·52; and 23·44 ± 3·01, P < 0·05, respectively, vs. 32·31 ± 1·61% in the control). The antithrombotic effect was confirmed by results in cross‐sectional studies performed in arterial vessels exposed to circulating blood. Values of thrombus and covered surface at 20 µM LA419 were, respectively, 13·67 ± 4·97% and 19·01 ± 5·89%; respect to controls 34·80 ± 5·29% and 37·93 ± 5·34% (P < 0·05). Moreover, LA419 reduced significantly thrombus area (88·45 ± 21·97 µm2; P < 0·05) with respect to controls (168·45 ± 21·97 µm2) and thrombus height, from an average of 10·27 ± 1·05 µm in nontreated blood to 7·16 ± 0·6 µm in treated samples (P < 0·05).

Conclusion  From the present data we can conclude that LA419 possesses a strong antiplatelet action, as demonstrated by its ability to significantly inhibit the interaction of platelet with highly thrombogenic collagen surfaces.
Glomerular hyperfiltration in type 1 diabetes mellitus results from primary changes in proximal tubular sodium handling without changes in volume expansion
Authors: Vervoort G. , Veldman B. , Berden J. H. M. , Smits P. , Wetzels J. F. M.
Published: April 2005

Background  Glomerular hyperfiltration plays a role in the pathophysiology of diabetic nephropathy. An increase in the glomerular filtration rate (GFR) could result from primary actions at the glomerular/vascular level or could be the consequence of a primary increase in proximal tubular sodium reabsorption resulting in systemic volume expansion. Recently it was hypothesized that an increase in sodium reabsorption may lead to glomerular hyperfiltration through the tubulo‐glomerular feedback mechanism (tubular‐hypothesis) without volume expansion.

Design  We have studied 54 normoalbuminuric patients with type 1 diabetes. The GFR was measured by inulin clearance. Proximal and distal sodium reabsorption were calculated according to standard formulas using the free water clearance technique. Plasma volume, measured by the 125I‐albumin method, atrial natriuretic peptide (ANP) and the second messenger cyclic guanosine‐3,5‐monophosphate (c‐GMP) were used as markers of extracellular volume expansion.

Results  Glomerular hyperfiltration (GFR ≥ 130 mL min−1 1·73 m−2) was present in 14 out of 55 patients with diabetes (25%). There were no differences in plasma volume between normo‐(NF) and hyper‐filtrating (HF) patients (2933 ± 423 in NF vs. 3026 ± 562 mL in HF, NS). Also plasma ANP and c‐GMP levels were not significantly different between the groups. The fractional proximal reabsorption of sodium was significantly increased in HF [fPRNa+ (%) 90·1 ± 2·0 vs. 91·5 ± 1·6, P = 0·02]. There were no differences in distal sodium reabsorption or distal sodium load (≈ macula densa concentration of NaCl) in both groups.

Conclusions  Our data suggest that the primary event in diabetic glomerular hyperfiltration is an increase in proximal tubular sodium reabsorption. They do not support the hypothesis that systemic volume expansion or ANP mediate glomerular hyperfiltration in patients with normoalbuminuric type 1 diabetes. As such, changes in tubular sodium handling most probably influence tubulo‐glomerular feedback.
Ecological and historical filters constraining spatial caddisfly distribution in Mediterranean rivers
Authors: BONADA NÚRIA , ZAMORA‐MUÑOZ CARMEN , RIERADEVALL MARIA , PRAT NARCÍS
Published: April 2005

1. Contemporary species distributions are determined by a mixture of ecological and historical filters acting on several spatial and temporal scales. Mediterranean climate areas are one of the world's biodiversity hotspots with a high level of endemicity, which is linked to complex ecological and historical factors.

2. This paper explores the ecological and historical factors constraining the distribution of caddisfly species on a large regional scale. A total of 69 taxa were collected from 140 sampling sites in 10 Iberian Mediterranean river basins. Approximately 74% of taxa can be considered rare, with the southern basins (the Baetic–Riffian region) having greater endemicity. The greatest richness, involving a mixture of northern and southern species, was found in the transitional area between the Baetic–Riffian region and the Hesperic Massif.

3. The historical processes occurring during the Tertiary (i.e. the junction of the Eurasian and African plates) explained 3.1% of species distribution, whereas ecological factors accounted for 20.7%. Only 0.3% was explained by the interaction of history and ecology. A set of multi‐scale ecological variables (i.e. basin, reach and bedform characteristics) defined five river types with specific caddisfly assemblages. The commonest caddisfly species accounted for the regional distribution pattern, while rare taxa contributed to the explanation of subtle patterns not shown by common species.

4. Despite the importance of historical factors for biogeography and the large scale used in our study, ecological variables better explained caddisfly distribution. This may be explained by the length of time since the historical process we are considering, the high dispersion and colonisation capacity of many caddisfly species, and the strong environmental gradient in the area. Because of the historical and environmental complexity of Mediterranean areas, rare taxa should be included in ecological studies so that the singularity of these ecosystems is not missed.
Top‐down and bottom‐up impacts of juvenile fish in a littoral reed stand
Authors: OKUN NILS , LEWIN WOLF‐CHRISTIAN , MEHNER THOMAS
Published: April 2005

1. Research has often focused on pelagic food chains and processes of lakes; less is known about the contribution of benthic energy flows to whole‐lake ecosystem energetics. This stems from the fact that the shoreline and littoral habitats, which provide a key linkage between sediment and water column, have only recently become a significant focus for study.

2. This study aimed to quantify the feeding and phosphorus allocation of a juvenile fish community in a littoral zone of a shallow lake in response to the biomass succession of the invertebrate prey community. Habitats comprising reed and adjacent open water were sampled over two consecutive years during day and night.

3. Although there were substantial year‐to‐year differences in the biomass of invertebrates, the fish community composition, diet consumption rates and phosphorus allocations were very similar in both study years. Biomasses and predation impacts by juvenile fish on prey groups were substantially higher within the reeds than in the adjacent open water habitat. This may be explained by the refuge‐seeking behaviour of the fish.

4. In general, invertebrates were negligibly influenced by fish feeding, with the exception for a strong top‐down control of large cladocerans. In response to the resulting low Daphnia biomass, fish were forced to switch to a higher degree of benthivory. Consequently, juvenile fish in littoral reed stands may shift benthic‐derived energy and phosphorus via the excretion of soluble reactive phosphorus into the open water.
Daily patterns of mixing and nutrient concentrations during early autumn circulation in a small sheltered lake
Authors: ALVAREZ‐COBELAS MIGUEL , VELASCO JOSÉ LUIS , VALLADOLID MARÍA , BALTANÁS ANGEL , ROJO CARMEN
Published: April 2005

1. Autumn circulation in lakes is currently conceived to occur very rapidly, being controlled mainly by wind‐power dynamics, decreasing irradiance and heat flux. In addition, autumn mixing is usually related to nutrient redistribution in the vertical column, resulting in its overall increase. To test these assumptions, mixing and nutrient dynamics in a Spanish small, wind‐sheltered, mesotrophic, seepage lake were studied daily during autumn circulation.

2. The seasonal erosion of the pycnocline in Las Madres Lake was the outcome of vertical and horizontal exchanges of heat and matter. The overall mixing of the water column lasted 3 months, which was an unexpected period for a rather shallow lake. Two periods of mixing could be envisaged until full circulation was attained. First, a slightly faster period of pycnocline deepening than that predicted by the heat flux and wind stress model of Fisher et al. (1979) occurred for 41 days, mixing most of the water column down to within two meters of the bottom. Then a much slower process took place promoting frequent instability of the bottom layer and resulting in entire mixing in a further 52 days.

3. Vertically, the whole mixing process was a response to weak surface cooling, resulting from the mild air temperatures of the semiarid climate of the area, and weak wind stress, because of low wind fetch and high shelter. Horizontally, a gravity current transporting cold, denser water from western shallower areas of the lake and materials produced by the decomposition of organic matter of littoral origin may produce a bottom layer of increased density, thus impinging on vertical stability. Seepage inputs of water of roughly constant temperature might also have increased bottom density. Bottom density enhancement resulted in a double diffusion process.

4. Only in‐lake nitrogen content increased until full circulation was attained, whereas carbon showed no trend and phosphorus declined. External processes, such as seepage exchange and atmospheric deposition, coupled to internal processes, such as nitrification, oxidised phosphorus precipitation and complexation with organic carbon, might have been responsible for the areal nutrient patterns observed.

5. Our study demonstrates that current models of water column mixing and nutrient redistribution in lakes during autumn circulation must be improved to encompass the effects of external inputs, including horizontal heat and matter exchange.
Flood effects on invertebrates, sediments and particulate organic matter in the hyporheic zone of a gravel‐bed stream
Authors: OLSEN DEAN A. , TOWNSEND COLIN R.
Published: April 2005

1. We investigated the effects of a flood on the fauna and physical habitat of the hyporheic zone of the Kye Burn, a fourth order gravel‐bed stream in New Zealand.

2. Freeze core hyporheic samples (to 50 cm depth) and benthic samples (to 10 cm) were taken, along with measurements of vertical hydrological gradient, before, 2 days after and 1 month after the flood (estimated return period: 1.5 years, estimated Qmax = 10.4 m3 s−1).

3. The composition of the hyporheos differed over the three sampling occasions with fewer taxa collected immediately postflood than preflood. The equitability of the community was higher on both postflood occasions, consistent with the reduced densities of two abundant taxa (Leptophlebiidae and Copepoda).

4. Total invertebrate abundance was lower on the postflood occasions than preflood in both benthic (0–10 cm) and hyporheic (10–50 cm) sediments. Several taxa, including asellotan isopods and amphipods, recovered within 1 month of the event. Hyporheic densities of larval Hydora and nematodes did not differ among the three sampling occasions, but the water mite Pseudotryssaturus was more abundant 1 month after the flood than preflood. There was no evidence of vertical movements (to 50 cm) by any taxa in response to the flood.

5. The proportion of fine sediments (<1 mm) in the subsurface sediments (10–50 cm) increased over the three sampling occasions and median particle size declined, but sediment porosity did not change. More particulate organic matter was found in the sediments after the flood.

6. Our study provides little evidence that the hyporheic zone (to 50 cm) acted as a significant refuge during the flood event, although movements to or recolonisation from sediments deeper than 50 cm could explain the recovery of many crustacean and mite taxa within 1 month.
Impact of migratory snow geese on nitrogen and phosphorus dynamics in a freshwater reservoir
Authors: OLSON MARK H. , HAGE MELISSA M. , BINKLEY MARK D. , BINDER JAMES R.
Published: April 2005

1. We examined impacts of nutrient loading, particularly of nitrogen and phosphorus, from greater snow geese (Chen caerulescens atlantica) on a reservoir in south‐eastern Pennsylvania, U.S.A. Approximately 100 000 geese use the reservoir for 2–6 weeks prior to their spring migration northward.

2. We estimated the magnitude of nutrient loading by geese during their presence and compared that to surface input and output rates. We also conducted nutrient limitation bioassay experiments to examine patterns of algal nutrient limitation upstream and downstream of the reservoir.

3. During their presence from 1 February to 27 March 2001, snow geese contributed 85–93% of the phosphorus and 33–44% of the nitrogen loaded to the reservoir. Both nutrients were exported from the reservoir slowly rather than as a quick pulse. Consequently, phosphorus concentrations in the outflow were higher than in the inflow from February to the end of July. However, nitrogen concentrations were consistently lower in the outflow than the inflow.

4. Nutrient limitation bioassays conducted in June and July indicated that primary production in the outflow was limited by nitrogen whereas the inflow was co‐limited by nitrogen and phosphorus. Further downstream from the reservoir, primary production was consistently phosphorus limited. Therefore, nitrogen limitation persisted long after the geese had left, but was relatively localised.
Flagellate nutritional versatility as a key to survival in two contrasting Antarctic saline lakes
Authors: LAYBOURN‐PARRY JOHANNA , MARSHALL WILLIAM A. , MARCHANT HARVEY J.
Published: April 2005

1. Seasonal patterns of grazing and photosynthesis were investigated in two saline Antarctic lakes (Highway and Ace) in the Vestfold Hills (68°S). The phototrophic nanoflagellate (PNAN) community was dominated by Pyramimonas gelidicola and two morphological forms of a cryptophyte species that occurred throughout the year. Both species were mixotrophic on bacteria, and in Highway Lake they also exploited dissolved organic carbon as determined by the uptake of fluorescently labelled dextrans.

2. Clearance rates ranged between 0.02 and 0.21 nL h−1 cell−1 in Ace Lake and 0.004–1.05 nL h−1 cell−1 in Highway Lake. On occasion cryptophyte grazing equalled that of the heterotrophic nanoflagellates (HNAN).

3. Photosynthetic rates showed similar trends in both lakes, but there were differences in chlorophyll a specific rates and photosynthetic efficiency, probably related to the meromictic characteristic of Ace Lake. Primary production was measurable in winter and peaked in summer following the maxima of mixotroph grazing.

4. The HNAN community of Highway Lake achieved clearance rates of 0.02–1.80 nL h−1 cell−1 and removing between 50 and 693 ng bacterial carbon L−1 day−1, with highest impact in winter when HNAN were most abundant. The HNAN also ingested fluorescently labelled dextrans showing a preference for 4 and 500 kDa molecules. The more diverse HNAN community of Ace Lake had lower clearance rates (0.04–0.37 nL h−1 cell−1) and exerted a lower grazing pressure on bacterioplankton. In Highway Lake, where the HNAN community was dominated by the choanoflagellate Diaphanoeca grandis, there was a significant correlation between mean cell volume and clearance rate.

5. The major feature was that the microbial plankton functioned throughout the year by employing nutritional versatility.