bluuebunny/crossref_metadata_2025 huggingface dataset:
Centralized vs decentralized adaptive generalized predictive control of a biodiesel reactor
Authors: Ho Yong Kuen , Mjalli Farouq S. , Yeoh Hak Koon
Published: May 2012

A second look at biodiesel reactor control using Recursive Least Squares (RLS)‐based adaptive Generalized Predictive Control (GPC) strategy revealed the possibility of a simpler alternative to the previously published centralized RLS‐based GPC controller (CRLS‐GPC). New results show that the simpler decentralized RLS‐based GPC controller (DRLS‐GPC) was on par with the more sophisticated centralized version in terms of servo and regulatory control, process interactions handling, and the resultant controller moves. Moreover, the simplified control scheme remained superior to the conventional Proportional–Integral controller. Such attributes make the DRLS‐GPC an attractive compromise between complexity and performance. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Solution properties of biobased hyperbranched polyols investigated by multiple‐detection size exclusion chromatography
Authors: Milic Jelena , Teraoka Iwao , Petrovic Zoran S.
Published: May 2012

We used multiple‐detection size exclusion chromatography and batch‐mode light scattering to follow the structural development of hydroxylated fatty acid methyl esters of soybean oil into hyperbranched (HB) polyol during polymerization by analyzing samples, collected at different times, in dilute solutions in tetrahydrofuran. The size of HB molecules was, as expected, smaller and more compact than that of their linear analogues of the same molecular weight (MW). Additionally, HB polyols were roughly spherical in shape. Plots of MW as a function of retention time and plots of the radius of gyration (Rg) as a function of MW showed an upturn; this indicated mixing of the high‐MW components in late‐eluting fractions, caused by either adsorption onto or trapping by the pore. For region of the plot before the turning points, the exponent in the Mark–Houwink equation was between 0.3 and 0.4. The exponent in the power relationship between Rg and MW was also below 0.5. It appeared that the shape of molecules for the same MW varied with the progress of the synthesis, as observed by a slope change in the viscometric radius dependence on MW for different HB polyol samples. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012
Characterization and structure analysis of PLGA/collagen nanofibrous membranes by electrospinning
Authors: Park Jong‐Seok , Choi Jong‐Bae , Jo Sun‐Young , Lim Youn‐Mook , Gwon Hui‐Jeong , Khil Myung Seob , Nho Young‐Chang
Published: May 2012

Poly(DL‐lactide‐co‐glycolide) (PLGA)/marine collagen nanofibrous membranes (PCNMs) with different weight ratio of PLGA to collagen were fabricated by an electrospinning method. The morphology and diameter distribution of electrospun nanofibers were investigated by scanning electron microscopy (SEM). SEM images showed that the morphology and diameter distribution of the nanofibers were mainly affected by the concentration of the solution, weight ratio of the PLGA/collagen, and applied electric voltage, respectively. To investigate the cell responses, MG‐63 cells isolated from a human mandible were cultured onto various substrates and their adhesion, spreading, and proliferation were examined. Immunofluorescent staining of MG‐63 cultured on the PCNMs demonstrated homogeneous localization of F‐Actin and vinculin in their cytoplasms. However, no mature adhesive structures were observed in the cell cultured on other substrates. Also, the cells seeded on the materials proliferated. These results suggest that PCNMs strongly support the attachment and growth of osteosarcoma cells. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A novel electrochemically and thermally stable polythiophene for photovoltaic application
Authors: Hanif Muddasir , Zuo Lijian , Yan Quanxiang , Hu Xiaolian , Shi Minmin , Chen Hongzheng
Published: May 2012

Conjugated polymers having good electrochemical and thermal stability are highly desired in optoelectronics. We report a new polythiophene consisting of alternating 4,4′‐didodecyl‐2,2′‐bithiophene and terthiophene units (HPL1) synthesized via Stille coupling reaction. The optical band gap of HPL1 (1.92 eV) is similar to that of regioregular poly(3‐hexylthiophene) (rr‐P3HT, 1.89 eV). In comparison to rr‐P3HT, the HPL1 when subjected to the cyclic voltammetry as thin film shows much superior electrochemical stability and a lower highest occupied molecular orbital energy level (−4.87 eV for rr‐P3HT and −4.95 eV for HPL1). The transient photoluminescence study of HPL1 and rr‐P3HT shows that both materials have two exciton decay processes, and the excitons of rr‐P3HT are quenched more quickly. The onset decomposition, Td for rr‐P3HT (465°C) is 4°C lower than HPL1 (469°C). Preliminary photovoltaic study disclosed that the polymer solar cell based on HPL1:[6,6]‐phenyl‐C61‐butyric acid methyl ester blend showed a power conversion efficiency of 0.63%, with a Voc of 0.6 V, and a short circuit current (Jsc) of 2.79 mA cm−2 under AM 1.5 illumination (100 mW cm−2). The whole study provided an important example to design new electrochemically and thermally stable polymers with longer exciton life time for application in bulk heterojunction polymer solar cells. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effects of chitosan characteristics on the physicochemical properties, antibacterial activity, and cytotoxicity of chitosan/2‐glycerophosphate/nanosilver hydrogels
Authors: Chang Hsiang‐Wei , Lin Ya‐Shen , Tsai Ying‐Die , Tsai Min‐Lang
Published: May 2012

The effects of molecular weight (MW) and the degree of deacetylation (DD) of chitosan (CS) on the physicochemical properties, antibacterial activity, and cytotoxicity of CS/2‐glycerophosphate (GP)/nanosilver hydrogel in the development of a thermosensitive in situ formed wound dressing are examined herein. The gelation temperatures for the hydrogels were measured in the range of 32–37°C by manipulating the MW and DD of CS and the GP concentration. The structure of 88% DD CS hydrogel was more porous, uniform, and connective than that of the 80% DD CS hydrogel. The superior water vapor transmission rates of hydrogels with 80% and 88% DD CS were 7150 ± 52 and 9044 ± 221 gm−2 d−1, respectively. The skin permeations of nanosilver by the 80% and 88% DD CS hydrogels were 3.82 and 4.99 μg cm−2, respectively, in 24 h tests. Both the hydrogels with 6 and 12 ppm nanosilver showed cytotoxicity for HS68 cells. The diameters of the hydrogel's inhibition zones for Pseudomonas aeruginosa and Staphylococcus aureus increased when the concentration of nanosilver increased and the MW of the CS decreased. Therefore, the hydrogel could be prepared with lower MW CS and lower concentration of nanosilver in order to reduce the cytotoxicity of nanosilver, while maintaining similar antibacterial activity for a hydrogel prepared with higher concentration nanosilver and higher MW CS. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Radiation synthesis and characterization of poly(ethylene oxide)/chitosan hydrogels
Authors: Branca C. , Auditore L. , Loria D. , Trimarchi M. , Wanderlingh U.
Published: May 2012

Recent advances in hydrogel technology have focused on finding more biocompatible, nontoxic materials intended for pharmaceutical and biomedical applications. In this study, a series of pH‐sensitive hydrogels were prepared from poly(ethylene oxide) (PEO) and chitosan in aqueous solutions by electron beam irradiation. This method is a suitable tool for the formation of biocompatible hydrogels because in radiation processing no initiators or crosslinkers, potentially toxic and difficult to remove, are needed. In this frame, also the PEO and chitosan choice was based on their characteristic of low toxicity. The properties of the prepared hydrogels were investigated in terms of the gel fraction and of the swelling behavior in solutions at different pHs. Some swelling kinetic and diffusional parameters were also determined. The observed properties show that increasing the chitosan content, or lowering the pH, the crosslinking density of these networks increases inducing the formation of more stable, but less swellable, hydrogels. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Anion exchange membranes derived from nafion precursor for the alkaline fuel cell: Effect of cation type on properties
Authors: Salerno Holly L. S. , Elabd Yossef A.
Published: May 2012

Highly stable hydroxide conducting membranes are necessary for solid‐state alkaline fuel cells to have long performance lifetimes. In this study, we used solid‐state chemistry to synthesize Nafion‐based anion exchange membranes (AEMs) with a variety of covalently attached cations, including trimethylammonium, trimethylphosphonium, piperazinium, pyrrolidinium, pyridinium, and quaternized 1,4‐diazabicyclo[2.2.2]octane. Infrared spectroscopy confirms a partial asymmetric functionalization of all cations with the exception of pyridinium. The AEMs that were successfully synthesized all exhibited sufficient water uptake and conductivity. The effect of cation type on AEM chemical and thermal stability was investigated as a function of various conditions (e.g., hydration levels, temperature, and pH). High chemical and thermal stability was observed for all successfully synthesized AEMs with the exception of the trimethylphosphonium cation AEM. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of cobalt coated nickel powders for improving the stability of the resistivity of PPTC materials
Authors: Fang Bin , Gao Sheng , Ge Xueping , Yang Cunzhong
Published: May 2012

Nickel powders coated by cobalt (Co@Ni powders) on the surface have been obtained by reduction in the ethylene glycol. The morphology and composition were characterized by scanning electron microscope and energy dispersive X‐ray spectroscopy. The valence states of cobalt in the sample were determined by X‐ray photoelectron spectroscopy. The Co@Ni powders were used as the electrically conductive fillers in the polymeric positive temperature coefficient (PPTC) materials in which polyethylene was used as the matrix. The stability of the resistivity of PPTC materials has been improved due to the protection and electrical conductivity of the cobalt layers on the surface of Ni powders. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of poly(amido amine)‐derived dendrimers with pendant benzoxazine groups and their thermal behavior
Authors: Lu Yanbing , Chen Junren , Lu Yunlong , Gai Pengbo , Zhong Hailin
Published: May 2012

Two novel dendrimer‐derived compounds with pendant benzoxazine, named 0G benzoxazine (0G BOZ) and 1G benzoxazine (1G BOZ), were prepared using 0G poly(amido amine) (PAMAM) and 1G PAMAM, phenol, and paraformaldehyde. Effects of different generations of PAMAM on curing kinetics and thermal properties were investigated. Differential scanning calorimetric (DSC) measurements of the 0G BOZ and 1G BOZ were carried out at different heating rates of 5, 10, 15, and 20 K/min. Kinetic analysis by Kissinger's and Ozawa's method revealed the activation energy (Ea) of 0G BOZ were 109.1 and 109.3 kJ mol−1, respectively, and those of 1G BOZ were 88.0 and 91.4 kJ mol−1. The autocatalytic kinetic model was found to be the best description of the investigated curing reactions. In addition, the predicted curves from our kinetic models fit well with the nonisothermal DSC thermograms. Thermogravimetrical analysis of cured resin of 0G BOZ and 1G BOZ showed that the char yields of 0G BOZ and 1G BOZ were 37.6 and 26.3%, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
“Communities” in Community Engagement: Lessons Learned From Autism Research in South Korea and South Africa
Authors: Grinker Roy Richard , Chambers Nola , Njongwe Nono , Lagman Adrienne E. , Guthrie Whitney , Stronach Sheri , Richard Bonnie O. , Kauchali Shuaib , Killian Beverley , Chhagan Meera , Yucel Fikri , Kudumu Mwenda , Barker‐Cummings Christie , Grether Judith , Wetherby Amy M.
Published: May 2012

Little research has been conducted on behavioral characteristics of children with autism spectrum disorder (ASD) from diverse cultures within the US, or from countries outside of the US or Europe, with little reliable information yet reported from developing countries. We describe the process used to engage diverse communities in ASD research in two community‐based research projects—an epidemiologic investigation of 7‐ to 12‐year olds in South Korea and the Early Autism Project, an ASD detection program for 18‐ to 36‐month‐old Zulu‐speaking children in South Africa. Despite the differences in wealth between these communities, ASD is underdiagnosed in both settings, and generally not reported in clinical or educational records. Moreover, in both countries, there is low availability of services. In both cases, local knowledge helped researchers to address both ethnographic as well as practical problems. Researchers identified the ways in which these communities generate and negotiate the cultural meanings of developmental disorders. Researchers incorporated that knowledge, as they engaged communities in a research protocol, adapted and translated screening and diagnostic tools, and developed methods for screening, evaluating, and diagnosing children with ASD. Autism Res 2012, 5: 201–210. © 2012 International Society for Autism Research, Wiley Periodicals, Inc.
Family history and risk of hospital treatment for varicose veins in Sweden
Authors: Zöller B , Ji J , Sundquist J , Sundquist K
Published: May 2012

Background

Family history has been suggested as a risk factor for varicose veins, but recall bias may inflate the familial risks. The aim of this nationwide study was to determine familial risks for hospital treatment for varicose veins.

Methods

Data from the Swedish Multi-Generation Register of people aged 0-76 years were linked to Hospital Discharge Register data for 1964–2008. Standardized incidence ratios (SIRs) were calculated for individuals whose relatives were treated in hospital for varicose veins and compared with those whose relatives were not. Only main diagnoses of varicose veins were considered.

Results

A total of 39 396 people had hospital treatment for varicose veins. The familial SIR among offspring with one affected parent was 2·39 (95 per cent confidence interval 2·32 to 2·46). The SIR for those with one affected sibling was 2·86 (2·76 to 2·97). SIRs were increased in both men and women. The SIR for individuals with two or more affected siblings or with two affected parents was 5·88 (5·28 to 6·53) and 5·52 (4·77 to 6·36) respectively. The SIR for the wives of men treated for varicose veins was 1·69 (1·59 to 1·80); that for the husbands of women treated for varicose veins was 1·68 (1·58 to 1·79).

Conclusion

Using the Swedish Hospital Discharge Register, and thereby eliminating recall bias, family history of hospital treatment for varicose veins was associated with an increased risk of similar treatment among relatives. The increased spousal risk suggests a contribution from non-genetic factors.
Mood symptoms contribute to working memory decrement in active‐duty soldiers being treated for posttraumatic stress disorder
Authors: Dretsch Michael N. , Thiel Kenneth J. , Athy Jeremy R. , Irvin Clinton R. , Sirmon‐Fjordbak Bess , Salvatore Anthony
Published: May 2012

A significant proportion of military veterans of operations in Afghanistan and Iraq have been diagnosed with posttraumatic stress disorder (PTSD). Growing evidence suggests that neuropsychological deficits are a symptom of PTSD. The current study investigated neurocognitive functioning among soldiers diagnosed with PTSD. Specifically, active‐duty soldiers with and without a diagnosis of PTSD were assessed for performance on tests of attention and working memory. In addition, factors such as combat experience, depression, anxiety, PTSD symptom severity, and alcohol consumption were explored as possible mediators of group differences in neurocognitive functioning. Twenty‐three active‐duty soldiers diagnosed with PTSD were matched with 23 healthy Soldier controls; all were administered the Attention Network Task (ANT), Backward Digit Span (BDS) task, Beck Depression Inventory, Beck Anxiety Inventory, PTSD Checklist—Military Version, Combat Exposure Scale, and Modified Drinking Behavior Questionnaire. Soldiers diagnosed with PTSD performed significantly worse on the working memory task (BDS) than healthy controls, and reported greater levels of PTSD symptoms, combat exposure, depression, and anxiety. However, after controlling for depression and anxiety symptoms, the relationship between PTSD and working memory was no longer present. The results indicate that PTSD is accompanied by deficits in working memory, which appear to be partially attributed to anxiety and depression symptoms.
Feasibility and safety of 7F sheathless guiding catheter during transradial coronary intervention
Authors: Kwan Tak W. , Cherukuri Sanjay , Huang Yili , Pancholy Samir , Daggubati Ramesh , Liou Michael , Coppola John , Saito Shigeru
Published: May 2012

Objective

The aim of our study is to assess the feasibility, safety, and rate of radial artery occlusion (RAO) using 7F sheathless guiding catheter in a large population undergoing transradial intervention (TRI).

Background

There is a frequent need for large bore guiding catheter to perform complex coronary interventions. Hydrophilic sheathless guiding catheters are not available in the US, therefore, we present the results of a multicenter study using the modified sheathless technique and readily available catheters.

Methods

Between December 2010 and February 2011, 116 consecutive patients from four tertiary US centers who underwent TRI using 7F sheathless guiding catheter were included in this study.

Results

In our study of 116 patients with 123 coronary lesions, 57 stenoses (49%) were complex interventions, which included patients with acute coronary syndromes, chronic total occlusion (CTO), bifurcation stenting, calcified lesions, left main artery, and saphenous venous graft interventions. Overall procedural success rate was 95%. At 7‐day, there were six patients (5%) with RAO, of which two of the six had severe radial artery spasm during the procedure. At 30‐day, the overall persistent RAO was only detected in three patients (2.5%), as three patients had return of antegrade radial artery flow.

Conclusions

In our multicenter study of 116 consecutive patients, using 7F sheathless guiding catheter to perform TRI is associated with a high procedural success (95%) and a low 30‐day RAO rate (2.5%). © 2012 Wiley Periodicals, Inc.
Balloon aortic valvuloplasty to bridge and triage patients in the era of trans‐catheter aortic valve implantation
Authors: Malkin Christopher J. , Judd Jo , Chew Derek P. , Sinhal Ajay
Published: May 2012

Objectives

To describe the use of balloon aortic valvuloplasty (BAV) as a method of selecting patients for definitive aortic valve therapy.

Background

BAV is a temporising treatment for aortic stenosis, previously used for palliation or bridge to surgery. The advent of transcatheter aortic valve implantation (TAVI) has developed a new indication for BAV–as a therapeutic trial.

Methods

This is a descriptive series of 33 consecutive patients treated between 2008 and 2010. Standard BAV retrograde technique was used. Hemodynamic results and survival were recorded; destination valve therapy was offered based on clinical response. The reasons for nonresponse were explored.

Results

Procedural success was achieved in all patients, valve area improved 0.36 ± 0.14 cm2, mean gradient by 20 ± 9.5 mm Hg and peak catheter gradient by 28.2 ± 17 mm Hg. Thirty‐day mortality was 3% and 6‐month mortality 15%. Twelve patients had no clinical improvement and were managed conservatively; two others demonstrated temporary occlusion of the left main by native leaflets during BAV. The remaining 19 patients improved and were offered valve therapy (10 TAVI and five aortic valve replacement). Post hoc analysis of the groups found higher prevalence of left ventricular impairment (90% vs. 29%, P = 0.001) and higher maintenance diuretic dose (Furosemide equivalent) 111.1 mg vs. 39.1 mg, P = 0.003) in the non‐responders.

Conclusion

BAV may be used to assess whether a patient might improve from definitive aortic valve treatment, particularly in those patients with left ventricular dysfunction or chronic obstructive pulmonary disease (COPD) where assessment is inconclusive or there remain concern about symptom reversibility. BAV can also be used to screen for the possibility of left main occlusion by native leaflets during TAVI. © 2012 Wiley Periodicals, Inc.
Transcatheter retrieval of an embolized methylmethacrylate glue fragment adherent to the right atrium using bidirectional snares
Authors: Grifka Ronald G. , Tapio Jason , Lee Kim J.
Published: May 2012

We report the successful transcatheter retrieval of a 6‐cm long, rigid methylmethacrylate glue fragment that embolized from a vertebral body to the right atrium. The glue fragment was adherent to the right atrial wall. Two snares were needed, advanced from opposite directions, to carefully separate the glue fragment from the atrial wall, then align it in a linear fashion directly into the sheath for an uneventful removal. © 2012 Wiley Periodicals, Inc.
Optimization of two‐step batch processes and the method of compensation for random error
Authors: Bjørkestøl Kirsten , Sivertsen Edvard , Næs Tormod
Published: May 2012

This paper considers the problem of the optimal setting of controllable variables in two‐step processes with quality constraints. The optimal setting minimizes the cost and satisfies quality constraints defined for the final output. The main emphasis is given to processes where it is possible to make intermediate measurements after the first processing step and to utilize these measurements before the control variables in the second step are set. Optimization based on this method of compensation for random error can yield substantially lower cost than does optimization based on a strategy where all variables are fixed before the process starts. An example of application of the method is taken from the food industry. Copyright © 2012 John Wiley & Sons, Ltd.
The QT interval in clinical hypercalcemia
Authors: Wortsman J. , Frank S.
Published: May 2012

Corrected QT intervals were determined in 13 patients with severe, chronic hypercalcemia. The QOTC interval was short in only 2 of 14 instances; QATC in 5 of 15 instances, and QETC in 5 of 16 instances. The correlations between serum calcium and the QTC measurement were not significant when evaluating either linear or curvilinear (quadratic) relationships. Small and inconsistent changes were found when comparing the QT intervals before the development of the hypercalcemic episode, during hypercalcemia, or after successful treatment. We conclude that shortening of the QT interval is an unreliable index of clinical (chronic) hypercalcemia.
Prevalence of primary T‐wave changes in young men and their relationship to psychological and anthropometric data
Authors: Atterhög J.‐H. , Malmberg P.
Published: May 2012

The T wave in leads II, V4, and V6 in the electrocardiograms of 1,401 consecutively entering 18‐year‐old male conscripts at a military processing center in 1975 were classified, and the relationship between the frequency of the T‐wave changes relative to the psychosocial and medical data of the subjects was examined. One percent of the conscripts had a negative T in one or more of these leads, and twelve percent showed some deviation from the “normal T,” usually a T wave of less than ten percent of the R‐wave amplitude. A common finding was the presence of a “notch” in the T wave of lead V4 (a negative deflection in the middle of a positive T wave). Those with T‐wave changes showed the same incidence of signs and history of heart disease as those with a normal T. However, those with an abnormal T showed higher heart rate and systolic blood pressure at rest. Further, they had more nervous symptoms and a higher consumption of alcohol and tranquilizers. These findings were as common in the larger group of flat T waves as in the smaller group with T‐wave changes of the type normally attributed to organic heart disease (i.e., having notched, or more or less inverted T waves without ST depression). The maximal work capacity and vital capacity were slightly lower in subjects with abnormal T waves. However, this was fully explained by lesser height. It is suggested that in the majority of these cases, T‐wave changes in young adults are due to increased sympathetic tone rather than to organic heart disease.
Why Perform Code‐to‐Code Comparisons: A Vacuum Arc Discharge Simulation Case Study
Authors: Timko H. , Crozier P. S. , Hopkins M. M. , Matyash K. , Schneider R.
Published: May 2012

Numerical modeling is increasingly becoming an indispensable tool for investigations in many fields of physics. Such modeling is especially useful in today's big science projects as a tool that can provide predictions and design parameters. The reliability of simulation results is thus essential. Code‐to‐code comparisons can help increase our confidence in simulation results, especially when other verification methods – such as comparison to theoretical models or experimental results – are limited or unavailable. In this paper, we describe a code‐to‐code comparison exercise wherein we compare one‐dimensional vacuum arc discharge simulation results from two independent particle‐in‐cell (PIC) codes. As part of our case study, we define a vacuum arc discharge test problem that can be used by other research groups for further comparison. Early disagreement between the two sets of our results motivated us to re‐examine the underlying methods in our codes. After remedying discrepancies, we observe good agreement in vacuum arc discharge time‐to‐breakdown, as well as in the time evolution of particle and current densities. This exercise demonstrates the usefulness of code‐to‐code comparisons and provides an example case study for the benefit of other research groups who may wish to carry out similar code‐to‐code comparisons (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discharge Operation Mode Manipulation of Radio Frequency Atmospheric Pressure Glow Discharges in Argon
Authors: Qian Y. J. , Ding K. , Song S. T. , Guo Y. , Zhang J. , Shi J. J.
Published: May 2012

Stable operation of radio frequency atmospheric glow discharges is widely desired by most processing applications for their conveniency and feasibility, many of which have been addressed with the noble gas of helium and low discharge current density in stable operation regime of α mode. Here, the operation mode manipulation of rf atmospheric pressure glow discharge in argon is investigated using a one‐dimensional self‐consistent modeling approach. Stable operation regime of α mode is found to expand with rinsing excitation frequency and reducing discharge gap distance. The sheath characteristics in terms of sheath voltage and sheath thickness are given to explain the of α ‐γ mode transition. Furthermore, stable operation of discharge in γ mode is proposed tobe achieved by introducing dielectric barriers, which is indicated by monotonously growing of applied voltage with discharge current density (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Automated analysis of GPI‐deficient leukocyte flow cytometric data using GemStone™
Authors: Miller David T. , Hunsberger Benjamin C. , Bagwell C. Bruce
Published: May 2012

Background:

Flow Cytometry is the standard for the detection of glycosylphosphatidylinositol (GPI)‐deficient clones in paroxysmal nocturnal hemoglobinuria (PNH) and related disorders. Although the International Clinical Cytometry Society (ICCS) and the International PNH Interest Group (IPIG) have published guidelines for PNH assays, data analysis has not been standardized. Current analyses use manual gating to enumerate PNH cells. We evaluate an automated approach to identify GPI‐deficient leukocytes using a GemStone™ (Verity Software House) probability state model (PSM).

Methods:

Five hundred and thirty patient samples were assayed on BD Canto II flow cytometers using a stain‐lyse‐wash technique. Populations were defined using CD15, CD45, CD64 and side scatter. GPI‐deficient myeloid cells were recognized as FLAER‐, CD24‐, and dim or absent CD16. GPI‐deficient monocytic cells were identified as FLAER‐ and CD14‐. The data were not censored in any way. A PSM was designed to enumerate monocytic and myeloid cells by adjusting the peaks and line spreads of the data, and recording the normal and GPI‐deficient counts. No operator adjustments were made to the automated analysis.

Results:

By human analysis, 53 of 530 samples showed GPI‐deficient clones. Automated analysis identified the same 53 clones; there were 0 false positives and 0 false negatives. Sensitivity was 100% and specificity 100%. Gating and automated results (percent GPI‐deficient cells) were highly correlated: r2 = 0.997 for monocytic cells, and r2 = 0.999 for myeloids. Mean absolute differences were 0.94% for monocytes and 0.78% for myeloid cells.

Conclusions:

Automated analysis of GPI‐deficient leukocytes produces results that agree strongly with gate‐based results. The probability‐based approach provides higher speed, objectivity, and reproducibility. © 2012 International Clinical Cytometry Society
Within and between population variation in plant traits predicts ecosystem functions associated with a dominant plant species
Authors: Breza Lauren C. , Souza Lara , Sanders Nathan J. , Classen Aimée T.
Published: May 2012

Linking intraspecific variation in plant traits to ecosystem carbon uptake may allow us to better predict how shift in populations shape ecosystem function. We investigated whether plant populations of a dominant old‐field plant species (Solidago altissima) differed in carbon dynamics and if variation in plant traits among genotypes and between populations predicted carbon dynamics. We established a common garden experiment with 35 genotypes from three populations of S. altissima from either Tennessee (southern populations) or Connecticut (northern populations) to ask whether: (1) southern and northern Solidago populations will differ in aboveground productivity, leaf area, flowering time and duration, and whole ecosystem carbon uptake, (2) intraspecific trait variation (growth and reproduction) will be related to intraspecific variation in gross ecosystem CO2 exchange (GEE) and net ecosystem CO2 exchange (NEE) within and between northern and southern populations. GEE and NEE were 4.8× and 2× greater in southern relative to northern populations. Moreover, southern populations produced 13× more aboveground biomass and 1.4× more inflorescence mass than did northern populations. Flowering dynamics (first‐ and last‐day flowering and flowering duration) varied significantly among genotypes in both the southern and northern populations, but plant performance and ecosystem function did not. Both productivity and inflorescence mass predicted NEE and GEE between S. altissima southern and northern populations. Taken together, our data demonstrate that variation between S. altissima populations in performance and flowering traits are strong predictors of ecosystem function in a dominant old‐field species and suggest that populations of the same species might differ substantially in their response to environmental perturbations.
Adding Rubidium and Cesium to the Homologous Series of Alkali Metal Compounds of (Trimethylsilyl)methanides and 2,2,6,6‐Tetramethylpiperidides
Authors: Clegg William , Kennedy Alan R. , Klett Jan , Mulvey Robert E. , Russo Luca
Published: May 2012

(Trimethylsilyl)methylrubidium [RbCH2SiMe3] (1) and (trimethylsilyl)methylcesium [CsCH2SiMe3] (2) were prepared by metathesis reactions of (trimethylsilyl)methyllithium [LiCH2SiMe3] with rubidium or cesium tert‐butoxide in n‐hexane. Both new compounds are pyrophoric powders which were characterised by NMR spectroscopy and elemental analyses. They can be used as deprotonating agents towards secondary amines such as 2,2,6,6‐tetramethylpiperidine (TMPH). The resulting amides [RbTMP] (3) and [CsTMP] (4) form temperature‐sensitive, n‐hexane‐insoluble orange solids. Treatment with the bidentate donor N,N,N′,N′‐tetramethylethylenediamine (TMEDA) produces the corresponding n‐hexane‐soluble complexes. The crystal structures of [(TMEDA)RbTMP] (3a) and [(TMEDA)CsTMP] (4a) were determined to be closely related to that of [(TMEDA)KTMP]. Thus they are dimers with frameworks that consist of four‐membered M–N–M–N rings (M = Rb, Cs or K, N = TMP). The versatility and stability observed should make these (trimethylsilyl)methyl and TMP compounds of rubidium (1, 3a) and cesium (2, 4a) valuable starting points for further exploration of the chemistry of these heavy alkali metals.
Asymmetries in peer interaction: The effect of social representations of gender and knowledge asymmetry on children's cognitive development
Authors: Zapiti Anna , Psaltis Charis
Published: May 2012

This study examines the role of social representations of gender and knowledge as sources of asymmetry on the features of children's interactions as well as on their cognitive development. The research was carried through an innovative pre‐test, first interaction, second interaction, post‐test design. One hundred fifty‐nine children of the same age (6.5–7.5 years old) but of different levels of knowledge of a spatial‐transformation task collaborated in same‐sex and opposite‐sex dyads to find a joint solution. In the first interaction, a child less developmentally advanced (NC) had to work with a child more developmentally advanced (TC), whereas in the second interaction of the same gender composition, the same NC had to work with a fresh NC. Cognitive progress was assessed using pre‐test to post‐test gains. The results revealed that the gender composition of the pairs and knowledge asymmetry influence not only the behavioral patterns and strategies that each partner employs in the interaction but also the cognitive outcomes of the children. These findings shed more light to the process through which socio‐cognitive conflict gets resolved, which was considered until now a “black box.” Copyright © 2012 John Wiley & Sons, Ltd.
Are Maladaptive Schema Domains and Perfectionism Related to Body Image Concerns in Eating Disorder Patients?
Authors: Boone Liesbet , Braet Caroline , Vandereycken Walter , Claes Laurence
Published: May 2012

Both maladaptive schemas (MS) and perfectionism have been associated with eating pathology. However, previous research has not examined these variables simultaneously and has not studied possible mediating relationships between MS and multidimensional perfectionism for body image concerns in eating disorder (ED) patients. Eighty‐eight female ED patients completed the Young Schema Questionnaire, the Frost Multidimensional Perfectionism Scale, and the Body Attitude Test. Body image concerns were found to be positively related to Personal Standards (PS) and Evaluative Concerns (EC) perfectionism and all five schema domains. PS Perfectionism was positively associated with Disconnection, Other‐directedness, and Overvigilance. EC Perfectionism was positively related to Disconnection, Impaired Autonomy, Other‐directedness, and Overvigilance. Moreover, EC perfectionism was found to be a significant mediator in the relationship between the schema domains Impaired Autonomy and Overvigilance and body image concerns. These findings denote the importance to address both core beliefs and perfectionism in ED treatment. Copyright © 2012 John Wiley & Sons, Ltd and Eating Disorders Association.
Burden associated with the presence of anosognosia in Alzheimer's disease
Authors: Turró‐Garriga Oriol , Garre‐Olmo Josep , Vilalta‐Franch Joan , Conde‐Sala Josep Lluís , de Gracia Blanco Manuel , López‐Pousa Secundino
Published: May 2012

Objectives

Anosognosia is the lack of deficit awareness, and it is a common symptom in patients with Alzheimer's disease (AD). The objective of this study was to assess the relationship between anosognosia and caregiver burden.

Methods

This was a cross‐sectional, analytical study of patients who were diagnosed with AD and their caregivers. Anosognosia was evaluated using the Experimenter Rating Scale, and caregiver burden was evaluated using the Burden Interview (BI). Using the BI's comprehensive scoring and each of its five factors as dependent variables, we adjusted six linear regression models to determine the effect of anosognosia on caregiver burden.

Results

The sample consisted of 124 patients and 124 caregivers. The mean patient age was 78.9 years (SD = 6.9); the mean caregiver age was 59.7 years (SD = 13.6), and 66.6% of the caregivers were women. The prevalence of anosognosia was 24.2% (95% confidence interval = 16.7–33.3). The degree of caregiver burden was associated with the degree of anosognosia (r2 = 0.426; standardised beta [βs] = 0.346; p < 0.001), which explained 14.7% of the variance. For the BI factors, the Experimenter Rating Scale was associated with physical and social burden (r2 = 0.452; βs = 0.378; p < 0.001), relationship of dependence (r2 = 0.301; βs = 0.203; p = 0.010) and emotional stress (r2 = 0.212; βs = 0.227; p = 0.014).

Conclusions

The presence of anosognosia in patients with AD is an independent factor that increases caregiver burden by increasing physical wear, social isolation, dependence and tension related to patient care. Copyright © 2012 John Wiley & Sons, Ltd.
Does the Addenbrooke's Cognitive Examination‐revised add to the Mini‐Mental State Examination in established Alzheimer disease? Results from a national dementia research register
Authors: Law Emma , Connelly Peter J. , Randall Emma , McNeill Catriona , Fox Helen C. , Parra Mario A. , Hudson Justine , Whyte Leigh‐Ann , Johnstone Jane , Gray Sarah , Starr John M.
Published: May 2012

Objective

To evaluate how much the Addenbrooke's Cognitive Examination‐revised (ACE‐R) improves the estimate of cognitive ability from the Mini‐Mental State Examination (MMSE) in people with Alzheimer disease (AD).

Methods

We examined itemized data in people with AD who were on the Scottish Dementia Research Interest Register drawn from eight centres across Scotland, covering 75% of the Scottish population. ACE‐R items that comprise the MMSE and those that did not (non‐MMSE items) were summed separately. We residualized MMSE total on non‐MMSE total and vice versa to derive a measure of the variance unique to each.

Results

Five hundred and one (258 male, 243 female) participants, mean age 75.7 (range 52–94) years were on the register, of whom 329 (160 men, 169 women) had AD. Of those with AD, 309 had a mean MMSE of 20.5 and mean ACE‐R of 57.5 measured with Pearson r = 0.92 between MMSE and ACE‐R totals, and the regression equation ACE‐R score = 3.0 × MMSE − 4.1. The unique non‐MMSE items score correlated with ACE‐R total r = 0.40 (16% of ACE‐R variance).

Conclusions

The ACE‐R and MMSE total scores are highly correlated. In this clinical sample of people with established AD, for an MMSE score of 24, the predicted ACE‐R score was 67.9 with 95% confidence intervals of 61.6–75.4. The extra non‐MMSE ACE‐R items improve estimates of cognitive ability by 16%. Copyright © 2012 John Wiley & Sons, Ltd.
ALTERNATIVE APPROACHES FOR ECONOMETRIC ANALYSIS OF PANEL COUNT DATA USING DYNAMIC LATENT CLASS MODELS (WITH APPLICATION TO DOCTOR VISITS DATA)
Authors: Hyppolite Judex , Trivedi Pravin
Published: May 2012

Cross‐sectional latent class regression models, also known as switching regressions or hidden Markov models, cannot identify transitions between classes that may occur over time. This limitation can potentially be overcome when panel data are available. For such data, we develop a sequence of models that combine features of the static cross‐sectional latent class (finite mixture) models with those of hidden Markov models. We model the probability of movement between categories in terms of a Markovian structure, which links the current state with a previous state, where state may refer to the category of an individual. This article presents a suite of mixture models of varying degree of complexity and flexibility for use in a panel count data setting, beginning with a baseline model which is a two‐component mixture of Poisson distribution in which latent classes are fixed and permanent. Sequentially, we extend this framework (i) to allow the mixing proportions to be smoothly varying continuous functions of time‐varying covariates, (ii) to add time dependence to the benchmark model by modeling the class‐indicator variable as a first‐order Markov chain and (iii) to extend item (i) by making it dynamic and introducing covariate dependence in the transition probabilities. We develop and implement estimation algorithms for these models and provide an empirical illustration using 1995–1999 panel data on the number of doctor visits derived from the German Socio‐Economic Panel. Copyright © 2012 John Wiley & Sons, Ltd.
MEDIATING ROLE OF EDUCATION AND LIFESTYLES IN THE RELATIONSHIP BETWEEN EARLY‐LIFE CONDITIONS AND HEALTH: EVIDENCE FROM THE 1958 BRITISH COHORT
Authors: Tubeuf Sandy , Jusot Florence , Bricard Damien
Published: May 2012

The paper focuses on the long‐term effects of early‐life conditions with comparison to lifestyles and educational attainment on health status in a cohort of British people born in 1958. Using the longitudinal follow‐up data at age 23, 33, 42 and 46, we build a dynamic model to investigate the influence of each determinant on health and the mediating role of education and lifestyles in the relationship between early‐life conditions and later health. Direct and indirect effects of early‐life conditions on adult health are explored using auxiliary linear regressions of education and lifestyles and panel Probit specifications of self‐assessed health with random effects addressing individual unexplained heterogeneity. Our study shows that early‐life conditions are important parameters for adult health accounting for almost 20% of explained health inequality when mediating effects are identified. The contribution of lifestyles reduces from 32% down to 25% when indirect effects of early‐life conditions and education are distinguished. Noticeably, the absence of father at the time of birth and experience of financial hardships represent the lead factors for direct effects on health. The absence of obesity at 16 influences health both directly and indirectly working through lifestyles. Copyright © 2012 John Wiley & Sons, Ltd.
An exploration of decision support for drivers, inside and outside the vehicle
Authors: Drew Daniel A. , Hayes Caroline C.
Published: May 2012

The purpose of this study was to investigate the feasibility and future promise of decision support systems (DSS A driving simulator study compared three DSSs: a dynamic road sign, displays on the side mirrors, and a vibrating seat (haptic).) inside the vehicle relative to a particular, well‐tested dynamic road sign external to the vehicle. Independent variables included display placement and modality (visual vs. haptic). Dependent variables included measurements of safe driving behavior and usability. A follow‐on focus group study was conducted to gain further insights into the results and improvement ideas. The vibrating seat yielded significantly better safety margins than the dynamic road sign. Haptic DSSs inside the vehicle may have more safety benefits than visual DSSs inside or outside the vehicle. Further investigation is needed to determine what properties of the haptic interface – reduced interference with visual driving tasks, message salience, simplicity, or some combination – are responsible for the advantage. © 2012 Wiley Periodicals, Inc.
Examining the Effects of Conformal Terrain Features in Advanced Head‐Up Displays on Flight Performance and Pilot Situation Awareness
Authors: Kim Sang‐Hwan , Kaber David B.
Published: May 2012

Synthetic vision systems (SVS) render terrain features for pilots through cockpit displays using a GPS database and three‐dimensional graphical models. Enhanced vision systems (EVS) present infrared imagery of terrain using a forward‐looking sensor in the nose of an aircraft. The ultimate goal of SVS and EVS technologies is to support pilots in achieving safety under low‐visibility and night conditions comparable to clear, day conditions. This study assessed pilot performance and situation awareness (SA) effects of SVS and EVS imagery in an advanced head‐up display (HUD) during a simulated landing approach under instrument meteorological conditions. Videos of the landing with various HUD configurations were presented to eight pilots with a superimposed tracking task. The independent variables included four HUD feature configurations (baseline [no terrain imagery], SVS, EVS, and a combination of SVS and EVS), two visibility conditions, and four legs of the flight. Results indicated that SVS increased overall SA but degraded flight path control performance because of visual confusion with other display features. EVS increased flight path control accuracy but decreased system (aircraft) awareness because of visual distractions. The combination of SVS and EVS generated offsetting effects. Display configurations did not affect pilot spatial awareness. Flight performance was not different among phases of the approach, but levels and types of pilot SA did vary from leg to leg. These results are applicable to development of adaptive HUD features to support pilot performance. They support the use of multidimensional measures of SA for insight on pilot information processing with advanced aviation displays. © 2012 Wiley Periodicals, Inc.
Analytical approaches for thermal analysis of radiative fin with a step change in thickness and variable thermal conductivity
Authors: Torabi Mohsen , Yaghoobi Hessameddin
Published: May 2012

In this paper, heat transfer in a straight fin with a step change in thickness and variable thermal conductivity which is losing heat by radiation to its surroundings is analyzed. The calculations are carried out by using the differential transformation method (DTM) and variational iteration method (VIM) that can be applied to various types of differential equations. The results obtained employing the DTM and VIM are compared with a finite difference technique with Richardson extrapolation which is an accurate numerical solution to verify the accuracy of the proposed methods. As an important result, it is depicted that the DTM results are more accurate in comparison with those obtained by VIM. After these verifications the effects of parameters such as thickness parameter α, dimensionless fin semi‐thickness δ, length ratio λ, thermal conductivity parameter β, and radiation–conduction parameter Nr, on the temperature distribution and fin efficiency are illustrated and explained. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21000
Simulation of mixed convection heat transfer in a horizontal channel with an open cavity containing a heated hollow cylinder
Authors: Rahman M.M. , Parvin S. , Rahim N.A. , Hasanuzzaman M. , Saidur R.
Published: May 2012

The objective of this paper is to numerically investigate the mixed convective flow and heat transfer controlled by a heated hollow cylinder inside an open cavity attached with a horizontal channel. All the boundaries of the channel and cavity are perfectly insulated while the inner surface of the cylinder is heated uniformly by heat flux q. The equations of conservation of mass, momentum, and energy were solved using adequate boundary conditions by Galarkin's weighted residual finite element technique. The solution has been performed in the computational domain as a whole with proper treatment at the solid/fluid interface. Computations have been conducted for Ra = 103–105, Prandtl number Pr varying from 0.7 to 7 and ratio of solid to fluid thermal conductivities from 0.2 to 50. Results are presented in terms of streamlines, isotherms, heat transfer rate in terms of the average Nusselt number (Nuav), drag force (D), and maximum bulk temperature (θmax). © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21002