bluuebunny/crossref_metadata_2025_split huggingface dataset:
Posterior Circulation Stroke is Associated with Prolonged Door-to-Needle Time
Authors: Sarraj Amrou , Medrek Sarah , Albright Karen , Martin-Schild Sheryl , Bibars Wafi , Vahidy Farhaan , Grotta James C. , Savitz Sean I. 
Published: March 2013

Background Lack of recognition of early symptoms of acute posterior circulation ischaemic stroke might delay timely diagnosis and treatment with tissue plasminogen activator. Aims and hypothesis We hypothesized that patients with posterior circulation stroke receive delayed thrombolytic treatment in comparison to anterior circulation stroke. We investigated the differences in times to evaluation or treatment between patients with anterior circulation ischaemic stroke and posterior circulation stroke in our aim to understand the barriers that might have caused these delays. Methods A cross-sectional study was conducted using consecutive patients presenting to our tertiary academic centre with acute ischaemic stroke who were treated with intravenous tissue plasminogen activator within 4·5 h from symptom onset. We compared demographics, stroke severity, symptoms and signs, and time intervals among onset, emergency department arrival, emergency department physician evaluation, neurologist evaluation, brain imaging, and tissue plasminogen activator treatment in patients with anterior circulation stroke and posterior circulation stroke. Results Among 252 patients treated with intravenous tissue plasminogen activator, 12% had posterior circulation stroke. Patients with posterior circulation stroke had significantly lower median baseline the National Institutes of Health and Stroke Scale (NIHSS) score ( P = 0·01), higher frequency of nausea ( P < 0·01), vomiting ( P < 0·01), dizziness ( P < 0·01), and lower frequency of aphasia ( P = 0·002) or neglect ( P = 0·048). The emergency department physician evaluation-to-neurologist evaluation and door-to-needle intervals were significantly longer for posterior circulation stroke patients compared with anterior circulation stroke patients. The neurologist-to-needle time, however, was similar in the two groups. The presence of nausea and vomiting was associated with a longer time from emergency department evaluation to neurology evaluation and had a significant association with delayed treatment. Conclusions Posterior circulation stroke patients had a delay in neurology evaluation after initial emergency department evaluation and a delay in intravenous tissue plasminogen activator administration compared with anterior circulation stroke patients. There may be difficulties in rapidly recognizing the symptoms of posterior circulation stroke, in contrast to anterior circulation stroke, in the emergency department.
Diffusion Kinetics of Indium in TiO2 (Rutile)
Authors: Atanacio Armand J. , Bak Tadeusz , Nowotny Janusz , Prince Kathryn E. 
Published: March 2013

This work determines the self‐diffusion coefficients of indium in TiO2 single crystal (rutile). Diffusion concentration profiles were imposed by deposition of a thin surface layer of InCl3 on the TiO2 single crystal and subsequent annealing in the temperature range 1073–1573 K. The diffusion‐induced concentration profiles of indium as a function of depth were determined using secondary ion mass spectrometry (SIMS). These diffusion profiles were used to calculate the self‐diffusion coefficients of indium in the polycrystalline In2TiO5 surface layer and the TiO2 single crystal. The temperature dependence of the respective diffusion coefficients, in the range 1073–1573 K, can be expressed by the following formulas: urn:x-wiley:00027820:media:jace12244:jace12244-math-0001and urn:x-wiley:00027820:media:jace12244:jace12244-math-0002The obtained activation energy for bulk diffusion of indium in rutile (316 kJ/mol) is similar to that of zirconium in rutile (325 kJ/mol). The determined diffusion data can be used in selection of optimal processing conditions for TiO2–In2O3 solid solutions.
Evolution of Mineralogical Phases by27Aland29SiNMRinMK‐Ca(OH)2System Cured at 60°C
Authors: Frías Moisés , Martínez‐Ramírez Sagrario , Blasco Teresa , Rodríguez María Frías 
Published: March 2013

The evolution of the metastable phases in metakaolin/Ca(OH)2systems cured at high temperatures, remains mostly unknown, newer techniques may now help to establish both the kinetic mechanism of the pozzolanic reaction and the thermodynamic stability of the main hydrated hexagonal phases: Stratlingite (C2ASH8) and tetra calcium aluminate hydrate (C4AH13). For this reason this work examines the kinetics of the pozzolanic reaction in theMK/Ca(OH)2system over 123 d at 60°C using nuclear magnetic resonance spectroscopy (27Aland29SiNMR). The results obtained by27Aland29SiNMRshow that during the first 30 h, the metastable phasesC2ASH8andC4AH13, coexist with the cubic phase (C3ASH6) obtained directly from the pozzolanic reaction. The gel C–S–H is clearly identified after 21 h of reaction, whereas at shorter times the C–S–H bands overlap those with the unreacted metakaolin ones. After 123 d of pozzolanic reaction, the first signs of the cubic phase are detected, a consequence of the conversion reaction of the metastable phases, and a phenomenon not previously identified.
Effect of Polyvinylpyrrolidone Additions on the Rheology of Aqueous, Highly Loaded Alumina Suspensions
Authors: Acosta Manuel , Wiesner Valerie L. , Martinez Carlos J. , Trice Rodney W. , Youngblood Jeffrey P. 
Published: March 2013

The control of the rheological behavior of highly loaded ceramic/polymer suspensions affords the development of near‐net shape forming techniques. In this study, suspensions containing sub‐micrometer diameter alumina (up to 56 vol%) were fabricated using an anionic dispersant (≈4 vol%) and water‐soluble polyvinylpyrrolidone (PVP). The amount and ratio of molecular weights of PVP in the suspension were varied to influence flow behavior. The final pH of the system, ≈9.5, was higher than the isoelectric point (IEP) of alumina implying that the alumina powder possesses a negative surface charge. In the case of alumina at this pH, PVP does not adsorb onto the surface of the powder. The flow behavior of the PVP‐containing suspensions displayed yield‐pseudoplastic characteristics that closely agreed with the Herschel–Bulkley fluid model. The addition of PVP significantly changed the rheology of the system, increasing the shear yield stress and altering flow behavior. Interparticle interaction approximations of the suspensions were modeled to correlate with experimental observations.
Electric Field Assisted Sintering of Cubic Zirconia at 390°C
Authors: Downs John A. , Sglavo Vincenzo M. 
Published: March 2013

Using the flash sintering technique, cubic yttria‐stabilized zirconia is shown to sinter at 390°C, more than 1000°C below nominal sintering temperatures, by using a DC electric field of 2250 V/cm. Furthermore, flash sintering experiments performed with electric fields between 60 and 2250 V/cm were used to show that the relationship of the temperature at the onset of flash sintering (TOnset) and the applied field (E) follows the power relationship TOnset (K) = 2440 E−1/5.85(V/cm). Using this relationship, and considering the sintering of the sample in the absence of an electric field, the critical electric field to enter the flash sintering regime is shown to be 24.5 V/cm. For electric fields between this critical electric field and 2250 V/cm, the onset of flash sintering occurs in the same range of critical volumetric power dissipation, between 1 and 10 mW/mm3, suggesting this is a material property. Despite the volumetric power dissipation being the critical value for the onset of flash sintering behavior, the current density achieved during sintering appears to be more critical for densification rather than maximizing power dissipation.
Spark Plasma Sintering of SuperhardB4C–ZrB2Ceramics by Carbide Boronizing
Authors: Zou Ji , Huang Shui‐Gen , Vanmeensel Kim , Zhang Guo‐Jun , Vleugels Jef , Van der Biest Omer 
Published: March 2013

A carbide boronizing method was first developed to produce dense boron carbide‐ zirconium diboride (“B4C”–ZrB2) composites from zirconium carbide (ZrC) and amorphous boron powders (B) by Spark Plasma Sintering at 1800°C–2000°C. The stoichiometry of “B4C” could be tailored by changing initial boron content, which also has an influence on the processing. The self‐propagating high‐temperature synthesis could be ignited by 1 molZrCand 6 molBat around 1240°C, whereas it was suppressed at a level of 10 molB.B8C–ZrB2ceramics sintered at 1800°C with 1 moleZrCand 10 mole B exhibited super high hardness (40.36 GPa at 2.94 N and 33.4 GPa at 9.8 N). The primary reason for the unusual high hardness ofB8C–ZrB2ceramics was considered to be the formation of nano‐sizedZrB2grains.
Electro‐Sintering of Yttria‐Stabilized Cubic Zirconia
Authors: Kim Seung‐Wan , Kang Suk‐Joong L. , Chen I‐Wei 
Published: March 2013

Electro‐sintering, i.e., electrically enhanced densification without the assistance of Joule heating, has been observed in 70% dense 8 mol% Y2O3‐stabilized ZrO2 ceramics at temperatures well below those for conventional sintering. Remarkably, full density can be obtained without grain growth under a wide range of conditions, including those standard for solid oxide fuel cell (SOFS) and solid oxide electrolysis cell (SOEC), such as 840°C with 0.15 A/cm2. Microstructure evidence and scaling analysis suggest that electro‐sintering is aided by electro‐migration of pores, made possible by surface flow of cations across the pore meeting lattice/grain‐boundary counter flow of O2−. This allows pore removal from the anode/air interface and densification at unprecedentedly low temperatures. Shrinkage cracking caused by electro‐sintering of residual pores is envisioned as a potential damage mechanism in SOFC/SOEC 8YSZ membranes.
A Novel Test Method for Ultrafast Pulse Response Characteristics of ZnO Varistor Ceramics
Authors: Shi Wei , Xie Guangyong 
Published: March 2013

A ZnO varistors in series connected with a semi‐insulating GaAs photoconductive switches (SI‐GaAs PCSS's), a test method for ultrafast pulse response characteristics of ZnO varistor ceramics with DC bias was presented for the first time. The DC voltage distribution of the PCSS's and the varistors was measured in a dark state and the pulse response characteristics of the ZnO varistor ceramics was examined by a nanosecond laser pulse illuminating the PCSS's. The results indicate that the electric pulse output from the varistors includes capacitive current and conduction current and there is a time delay between their peaks. It is revealed that ZnO varistors has a nonlinear conductivity for the nanosecond electric impulse excitation and the barrier capacitance decay constant of the ceramics sample is 105 ns, which is explained through the analysis of examining the material structure and the conductive mechanisms.
Transparent Y3Al5O12: Li,Ce Ceramics for Thermal Neutron Detection
Authors: Chen Shi , Zhang Lihua , Kisslinger Kim , Wu Yiquan 
Published: March 2013

To exploit the potential applications of thermal neutron detection, yttrium aluminum garnet co‐doped with 1 mol% Ce3+ and 5 mol% Li+ was vacuum sintered into a transparent ceramic through solid‐state reaction. The transmittance of a 2 mm thick sample was measured to be as high as 80.3% in the visible range and the microstructural characterization indicated that Li ions could also act as a sintering aid. Excitation and emission spectra data further supported the assumption that the Li ions have substituted into the garnet lattice. Excitation and emission spectra data of the prepared ceramic were also obtained for use in the characterization of optical properties.
Exceptionally High Dielectric Constant in Ceramic Pr2CuO4
Authors: Salame Paresh H. , Prakash Om , Kulkarni A. R. 
Published: March 2013

The pristine layered cuprate Pr2CuO4 samples of >95% density were fabricated as thin disks. The samples, analyzed by X‐ray diffraction and Scanning electron microscopy, showed clean T′‐type phase with Rietveld refined lattice parameters a = b = 3.95805(±5) Å and c = 12.2262(±5) Å. The measured dielectric properties of the Pr2CuO4 ceramics, in the temperature range −100°C–150°C and frequencies (ν) 0.1 Hz–1 MHz, showed extremely high εr′ > 104 (above −30°C), and dissipation (tan δ = εr′′/εr′) between 0.1 and 5 (for 500 Hz ≤ ν ≤ 1 MHz, and −100 ≤ T ≤ 150°C). The ac conductivity of Pr2CuO4 ceramics ranged between 10−6 and 10−3 Scm−1 for the measured frequencies and temperatures, and showed frequency‐dependent double power law behavior akin to a modified Jonscher's power law.
The family experience following bone marrow or blood cell transplantation
Authors: Young Linda 
Published: March 2013

AbstractAimTo explore how families with children at home managed 4–12 months after an adult family member was discharged from the hospital to home following bone marrow or blood cell transplantation.BackgroundStudies of these families have been limited in number. The Family Management Style Framework offers a conceptual framework relevant to families with children who have an adult member who has undergone a bone marrow or blood cell transplant.DesignThis was a descriptive, qualitative, one‐point‐in‐time study.MethodContent analysis in relation to the three conceptual components of the Family Management Style Framework was employed; inductive thematic analysis determined the emergent conceptual dimensions present in the data. The sample was composed of 29 participants: 15 transplant recipients and 14 significant others who met the study criteria in 2008 and 2009. Each patient and his or her significant other were interviewed; the audio‐recorded interviews were analysed after transcription.FindingsThe three conceptual components of the Family Management Style Framework: (1) definition of the situation; (2) management behaviours; and (3) perceived consequences, were validated as relevant for this sample across all participants. New conceptual dimensions were also present, inclusive of recovery view, support base, financial picture, management domains, perceived consequences to the whole family, and perceived consequences to the dyad relationships.ConclusionThere are several overarching findings in this study, notably that recovery at home is a family experience. Implications for nursing practice include the need for effective transitional care for the patient and family.
Structural equation model testing the situation‐specific theory of heart failure self‐care
Authors: Vellone Ercole , Riegel Barbara , D'Agostino Fabio , Fida Roberta , Rocco Gennaro , Cocchieri Antonello , Alvaro Rosaria 
Published: March 2013

AbstractAimTo test the situation‐specific theory of heart failure self‐care with structural equation modelling.BackgroundSeveral authors have proposed theories on heart failure self‐care, but only the situation‐specific theory of heart failure self‐care by Riegel and Dickson is focused on the process that patients use to perform self‐care. This theory has never been tested with structural equation modelling.DesignA secondary analysis of data from a cross‐sectional study.MethodsPatients with heart failure were recruited in 21 cardiovascular centres across Italy during 2011. Data were collected with a sociodemographic questionnaire, chart abstraction for clinical data and the Self‐Care of Heart Failure Index v.6·2.ResultsA sample of 417 participants was enrolled in the study (59% males, mean age 72 years). The following propositions were tested and supported: Symptom monitoring correlates with treatment adherence; symptom monitoring and treatment adherence have a direct, positive relationship with symptom recognition and evaluation that in turn have a direct, positive relationship with treatment implementation; treatment implementation has a direct, positive relationship with treatment evaluation. In addition, the following three relationships were found: Symptom monitoring has a direct, positive relationship with treatment implementation; symptom recognition and evaluation have direct, positive relationships with treatment evaluation and symptom monitoring correlates with treatment evaluation. [Correction added on 9th April 2013, after first online publication: ‘…symptom monitoring correlates with treatment implementation.’ has been corrected to read ‘…symptom monitoring correlates with treatment evaluation.’]ConclusionThe data support the situation‐specific theory of heart failure self‐care with the addition of three new relationships that emerged from the analysis. Results of this study lend further support to the use of the situation‐specific theory of heart failure self‐care in research and practice.
Locating Existing Best Management Practices Within a Watershed: The Value of Multiple Methods
Authors: Grady Caitlin A. , Reimer Adam P. , Frankenberger Jane , Prokopy Linda Stalker 
Published: March 2013

AbstractThere is an increasing need to document the impacts of conservation‐related best management practices (BMPs) on water quality within a watershed. However, this impact analysis depends upon accurate geospatial locations of existing practices, which are difficult to obtain. This study demonstrates and evaluates three different methods for obtaining geospatial information for BMPs. This study was focused on the Eagle Creek Watershed, a mixed use watershed in central Indiana. We obtained geospatial information for BMPs through government records, producer interviews, and remote‐sensing aerial photo interpretation. Aerial photos were also used to validate the government records and producer interviews. This study shows the variation in results obtained from the three sources of information as well as the benefits and drawbacks of each method. Using only one method for obtaining BMP information can be incomplete, and this study demonstrates how multiple methods can be used for the most accurate picture.
Catheter Ablation of Atrial Fibrillation in Patients at Low Thrombo‐Embolic Risk: Efficacy and Safety of a Simplified Periprocedural Anticoagulation Strategy
Authors: DUYTSCHAEVER MATTIAS , BERTE BENJAMIN , ACENA MARTA , DE MEYER GRIM , BUN SOK‐SITHIKUN , VAN HEUVERSWYN FREDERIC , VANDEKERCKHOVE YVES , TAVERNIER RENE 
Published: March 2013

Aspirin and Low Molecular Weight Heparin in Patients Undergoing Catheter Ablation of AFBackgroundTo prevent thrombo‐embolic (TE) events during ablation of atrial fibrillation (AF), warfarin is recommended in all patients irrespective of baseline TE risk. We evaluated the efficacy and safety of a simplified periprocedural anticoagulation strategy of aspirin (ASA) and low molecular weight heparin (LMWH) in patients at low TE risk.MethodsWe collected data from 214 low TE risk patients (CHADS2 score ≤1 and no warfarin at baseline) undergoing pulmonary vein isolation. After discontinuation of ASA, periprocedural antithrombotic therapy consisted of therapeutic subcutaneous LMWH injections (nadroparin 1 mL/kg once daily) from 10 days before until 10 days after the procedure, followed by ASA in all patients. At the time of procedure, transesophageal echocardiography (TEE) was not performed on a routine basis. During the procedure, unfractionated heparin was administered to achieve an ACT between 350 and 400 seconds. Data on TE events (stroke or transient ischemic attack), cardiac tamponade/perforation, and major vascular access complications within 3 months after the procedure were collected.ResultsMean CHADS2 was 0.3 ± 0.5. TEE was performed in 3% of patients. No periprocedural TE events occurred. No cardiac tamponade/perforation was observed. Major vascular access complications occurred in 3 patients (1.4%). No permanent injury was observed (0%).ConclusionIn selected low TE risk patients undergoing ablation for AF, a short period of periprocedural therapeutic anticoagulation with LMWH together with aspirin is an effective and safe strategy to prevent TE events. If confirmed in a randomized trial, this approach might simplify periprocedural antithrombotic management in ablation of selected AF patients.
Using small‐area variations to inform health care service planning: what do we ‘need’ to know?
Authors: Mercuri Mathew , Birch Stephen , Gafni Amiram 
Published: March 2013

AbstractRationale, aims and objectivesAllocating resources on the basis of population need is a health care policy goal in many countries. Thus, resources must be allocated in accordance with need if stakeholders are to achieve policy goals. Small area methods have been presented as a means for revealing important information that can assist stakeholders in meeting policy goals. The purpose of this review is to examine the extent to which small area methods provide information relevant to meeting the goals of a needs‐based health care policy.MethodsWe present a conceptual framework explaining the terms ‘demand’, ‘need’, ‘use’ and ‘supply’, as commonly used in the literature. We critically review the literature on small area methods through the lens of this framework.Results‘Use’ cannot be used as a proxy or surrogate of ‘need’. Thus, if the goal of health care policy is to provide equal access for equal need, then traditional small area methods are inadequate because they measure small area variations in use of services in different populations, independent of the levels of need in those populations.ConclusionsSmall area methods can be modified by incorporating direct measures of relative population need from population health surveys or by adjusting population size for levels of health risks in populations such as the prevalence of smoking and low birth weight. This might improve what can be learned from studies employing small area methods if they are to inform needs‐based health care policies.
Advanced Age as a Risk Factor for Folate‐Associated Functional Cobalamin Deficiency
Authors: Solomon Lawrence R. 
Published: March 2013

ObjectivesTo determine whether high serum folate levels contribute to metabolite changes in elderly subjects with normal cobalamin levels.DesignCase series.SettingOutpatient clinic at a university‐based staff model health maintenance organization.ParticipantsTwo hundred thirty‐three ambulatory individuals without diabetes mellitus with normal renal function and normal cobalamin levels evaluated for cobalamin deficiency.MeasurementsCobalamin, serum folate, methylmalonic acid (MMA), and homocysteine.ResultsOlder individuals (≥60) with low‐normal cobalamin levels (201–300 pg/mL) had higher MMA and lower homocysteine levels when serum folate levels were high (>20 ng/mL) than when serum folate levels were normal (P < .02), but serum folate levels within the normal range were not a determinant of either metabolite. In younger subjects with low‐normal cobalamin levels, high serum folate levels were not associated with significant differences in either metabolite. At mid‐normal cobalamin levels (301–600 pg/mL), high serum folate levels were associated with lower homocysteine levels in older adults (P < .001) but not with differences in MMA in either age group. Cobalamin therapy decreased or normalized MMA and homocysteine in 89% or more of participants even at pretherapy cobalamin levels greater than 600 pg/mL.ConclusionHigh serum folate levels are associated with higher MMA levels when cobalamin levels are low‐normal, and this effect is age dependent, not progressive within the normal serum folate range (suggesting a threshold effect), and reversed by cobalamin therapy. Because MMA may be neurotoxic, these findings suggest caution in the use of folic acid supplements in elderly adults.