bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic and thermodynamic investigation of Arthrospira (Spirulina) platensis fed‐batch cultivation in a tubular photobioreactor using urea as nitrogen source
Authors: Morocho Jácome Ana Lucía , Converti Attilio , Sato Sunao , Monteiro de Carvalho João Carlos
Published: April 2012

BACKGROUND: Fed‐batch culture allows the cultivation of Arthrospira platensis using urea as nitrogen source. Tubular photobioreactors substantially increase cell growth, but the successful use of this cheap nitrogen source requires a knowledge of the kinetic and thermodynamic parameters of the process. This work aims at identifying the effect of two independent variables, temperature (T) and urea daily molar flow‐rate (U), on cell growth, biomass composition and thermodynamic parameters involved in this photosynthetic cultivation.

RESULTS: The optimal values obtained were T = 32 °C and U = 1.16 mmol L−1 d−1, under which the maximum cell concentration was 4186 ± 39 mg L−1, cell productivity 541 ± 5 mg L−1 d−1 and yield of biomass on nitrogen 14.3 ± 0.1 mg mg−1. Applying an Arrhenius‐type approach, the thermodynamic parameters of growth (ΔH* = 98.2 kJ mol−1; ΔS* = − 0.020 kJ mol−1 K−1; ΔG* = 104.1 kJ mol−1) and its thermal inactivation (${\Delta}H_{D}^{o} = 168.9$ kJ mol−1; ${\Delta}S_{D}^{o} = 0.459$ kJ mol−1 K−1; ${\Delta}G_{D}^{o} = 31.98$ kJ mol−1) were estimated.

CONCLUSIONS: To maximize cell growth T and U were simultaneously optimized. Biomass lipid content was not influenced by the experimental conditions, while protein content was dependent on both independent variables. Using urea as nitrogen source prevented the inhibitory effect already observed with ammonium salts. Copyright © 2012 Society of Chemical Industry
Oxalate decarboxylase of Trametes versicolor: biochemical characterization and performance in bleaching filtrates from the pulp and paper industry
Authors: Winestrand Sandra , Gandla Madhavi Latha , Hong Feng , Chen Qi Zhi , Jönsson Leif J.
Published: April 2012

BACKGROUND: Oxalate decarboxylase (ODC) from acid‐induced cultures of the white‐rot fungus Trametes versicolor was purified and characterized with respect to its biochemical properties and the possibility to utilize the enzyme for treatment of process water with the intention to prevent problems with calcium‐oxalate scaling in the pulp and paper industry.

RESULTS: Purified T. versicolor ODC was identified by tandem mass spectrometry. As estimated by using SDS‐PAGE, the molecular mass was 69 kDa, and 60 kDa after deglycosylation with N‐glycosidase F. The pH optimum was 2.5 and the temperature optimum was 40–45 °C. The effects of ten potential inhibitors in industrial filtrates were examined. The enzyme was sensitive to low concentrations (0.1 mmol L−1) of chlorite and sulfite. T. versicolor ODC exhibited activity in 16 filtrates collected from mechanical pulping and kraft pulping. It had higher activity than ODC from Aspergillus niger in all of the filtrates and higher activity than oxalate oxidase from barley in all filtrates except two.

CONCLUSIONS: The investigation shows basic biochemical properties of T. versicolor ODC and indicates that the enzyme may be useful for treatment of industrial filtrates under acidic conditions. Copyright © 2012 Society of Chemical Industry
A partnered approach to QA increases efficiency through early problem detection
Authors: Rubin Eileen Newman
Published: April 2012

Over the years, organizational leaders have employed a variety of process and product quality assurance (PPQA) programs to reduce costs and improve the quality of their operations. Each has its advantages and disadvantages. A new approach, partnering, combines the best of these strategies to increase organizational effectiveness while enabling flexibility. As one software unit at a defense contractor discovered, the strength of this technique lies in its emphasis on encouraging personnel to detect problems early in a process or product life cycle, when they can be most easily addressed. © 2012 Wiley Periodicals, Inc.
Multinationals' priorities may distort ISO standards in Chinese subsidiaries
Authors: Anglès Valérie
Published: April 2012

Standardized systems of management are looked to as universal references for business practitioners. Yet, studies of the ISO 9000 management system in China have shown that it is often not internalized or becomes distorted in the subsidiaries of multinational enterprises. Based on 36 interviews from 20 European subsidiaries of multinational enterprises, and three interviews with representatives of the main European certification bodies, this article highlights some of the underlying causes of the apparent misrepresentation of ISO 9000. It presents a typology of ISO 9000 adoption and distortion based on the social and organizational institutional context, showing the cognitive, normative, and regulative aspects, as well as the influence of learning priorities and organizational logic. The results reveal that the mistaken perception that ISO 9000 is a product guarantee is not only widespread in China, but even affects the way in which laws are formulated there. They also show that a multinational's own organizational priorities and logic can play a key role in this phenomenon. © 2012 Wiley Periodicals, Inc.
Comprehensive review of the diagnosis and treatment of biliary tract cancer 2012. PART I: Diagnosis‐clinical staging and pathology
Authors: Marsh Robert de W , Alonzo Marc , Bajaj Shailesh , Baker Marshall , Elton Eric , Farrell Thomas A , Gore Richard M , Hall Curtis , Nowak Jan , Roy Hemant , Shaikh Arif , Talamonti Mark S.
Published: April 2012

Biliary tract cancers (gallbladder cancer, intra‐ and extra‐hepatic cholangiocarcinoma, and selected periampullary cancers) accounted for 12,760 new cases of cancer in the USA in 2010. These tumors have a dismal prognosis with most patients presenting with advanced disease. Early, accurate diagnosis is essential, both for potential cure where possible and for optimal palliative therapy in all others. This review examines the currently available and emerging technologies for diagnosis and treatment of this group of diseases. J. Surg. Oncol. 2012; 106:332–338. © 2012 Wiley Periodicals, Inc.
Expression of FOXJ1 in hepatocellular carcinoma: Correlation with patients' prognosis and tumor cell proliferation
Authors: Chen Hong‐Wei , Huang Xiao‐Dong , Li Hong‐Chen , He Song , Ni Run‐Zhou , Chen Cui‐Hua , Peng Chen , Wu Gang , Wang Gui‐Hua , Wang Ying‐Ying , Zhao Yun‐Hong , Zhang Yi‐Xin , Shen Ai‐Guo , Wang Hui‐Min
Published: April 2012

FOXJ1 is a member of the forkhead box (FOX) family of transcription factors. Recent studies suggested that FOXJ1 may function as a tumor suppressor gene in breast cancer. To investigate the potential roles of FOXJ1 in hepatocellular carcinoma (HCC), expression of FOXJ1 was first examined in eight paired frozen HCC and adjacent noncancerous liver tissues by Western blot, and we found that FOXJ1 was upregulated in HCC specimens. In addition, immunohistochemistry was performed to confirm our results in 108 HCC samples. Moreover, we also evaluated its relation with clinicopathological variables and the prognostic significance. The data showed that high expression of FOXJ1 was associated with histological grade (P < 0.001), and FOXJ1 was positively correlated with proliferation marker Ki‐67 (P < 0.01). Univariate analysis suggested that FOXJ1 expression was associated with poor prognosis (P < 0.001). Multivariate analysis indicated that tumor grade (P < 0.0001), metastasis (P = 0.0451), tumor size (P = 0.0459), FOXJ1 (P = 0.0011), and Ki‐67 (P = 0.0006) were independent prognostic markers for HCC. Furthermore, we noted that there existed the change of the level of FOXJ1 subcellular localization during cell‐cycle transition in HepG2 cells by immunofluorescence and cell fractionation. Besides, we employed FOXJ1 overexpression/knockdown approaches to investigate the effects of FOXJ1 on HCC cell proliferation and cell‐cycle distribution and found that overexpression of FOXJ1 can promote tumor cell proliferation and cell‐cycle transition. Our results suggested that FOXJ1 was overexpressed in HCCs and associated with histological grade and poor prognosis. Overexpression of FOXJ1 was also involved in tumor cell proliferation and cell‐cycle progression in HCC cell lines. © 2012 Wiley Periodicals, Inc.
Ras‐induced melanoma transformation is associated with the proteasomal degradation of the transcriptional repressor ICER
Authors: Healey Marlene , Crow Marni S. , Molina Carlos A.
Published: April 2012

Activation of the mitogen‐activated protein kinase (MAPK) pathway targets the putative tumor suppressor protein inducible cAMP early repressor (ICER) to ubiquitin‐mediated proteasomal degradation [Yehia et al. JBC 2001; 276: 35272–35279]. We demonstrate that ICER proteasomal degradation is implicated in Ras/MAPK‐mediated melanoma tumorigenesis. In a system using Tyr/Tet‐Ras INK4a−/− transgenic mice and melanoma cells in culture termed R545 cells isolated from Tyr/Tet‐Ras INK4a−/− mice [Chin et al. Nature 1999; 400: 468–472], melanoma genesis and melanoma maintenance is strictly dependent upon expression of H‐RasV12G. We found that ICER protein was not expressed during melanoma genesis but was strongly expressed in regressing melanomas. Similarly in R545 cells, ICER protein expression was negatively regulated by H‐RasV12G. The expression of ICER mRNA was not affected by H‐RasV12G expression, suggesting that ICER regulation was post‐translational. Indeed, pharmacological inhibition of Ras activity or the proteasome abolished the degradation of ICER caused by H‐RasV12G expression indicating that RAS oncogene regulates the expression of ICER protein by targeting ICER to proteasomal degradation. By engineering clones of R545 melanoma cells stably transfected with ICER we were able to determine the prerequisite for Ras‐induced tumorigenesis. The reconstitution of physiological levels of ICER showed a significant decrease in cell growth, as well as inhibition of anchorage‐independent cell growth and tumorigenicity in nude mice. ICER was found to efficiently repress the expression of cyclin D1 in R545 cells due to the binding of ICER to the CRE in the cyclin D1 promoter. Taken together, we postulate that ICER protein might be targeted to degradation in human tumors where Ras is mutated. © 2012 Wiley Periodicals, Inc.
Stereochemie — eine Art moderne Form der Freskenmalerei
Authors: Guggolz Ernst
Published: April 2012

Druckfehler und falsche Erklärungen machen komplizierte Sachverhalte einfach und einfache Sachverhalte aufregend. Zum ersten Mal fehlen die fast schon obligatorischen freien Radikalen, dafür gibt es jetzt eine Extra‐Rubrik mit Übersetzungsfehlern. Ein rückblickender Beitrag zum Jahr der Chemie.
Using the economical order quantity formula for inventory control in one‐warehouse multiretailer systems
Authors: Stauffer Gautier
Published: April 2012

In this article, we deal with the inventory control of one single product in a distribution network consisting of one warehouse and n retailers where the retailers face continuous demands with constant rates. We study two policies for this problem that are derived from the application of the classical economical ordering quantity formula at each location: the first policy is purely single‐echelon, whereas the second synchronizes the reorder intervals between the different installations and thus constitutes a first step toward a multiechelon perspective. We show that those policies are, respectively,
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‐ and 1.275‐optimal. We then conduct computational experiments and demonstrate that our second policy exhibits excellent average performance and improves substantially over the pure single‐echelon policy: in particular it deviates from Roundy's celebrated algorithm by less than 5%. This result indicates that in this simple setting, a great part of the benefit of shifting to a multiechelon perspective can be obtained by the most natural synchronization scheme between the different installations, and adapting single‐echelon policies can be efficient at managing the inventory in simple distribution networks, confirming observations of practitioners. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012
A probabilistic nonlocal model for crack initiation and propagation in heterogeneous brittle materials
Authors: Guy Nicolas , Seyedi Darius M. , Hild François
Published: April 2012

A probabilistic damage model is developed to study crack initiation and growth in quasi‐brittle materials. Two different thresholds are considered to describe these mechanisms. A Weibull model is used to account for the randomness of crack initiation(s) and then a fracture mechanics based threshold is considered to model crack propagation. The model is integrated in a finite element code via a nonlocal damage approach. A regularization operator based on a stress regularization is introduced. Both damage thresholds are checked using the ‘regularized’ stress field to avoid mesh dependence. The interaction between propagating cracks and potential initiation sites is accounted for. Copyright © 2012 John Wiley & Sons, Ltd.
Collocation Trefftz methods for the stokes equations with singularity
Authors: Li Zi‐Cai , Lee Ming‐Gong , Chiang John Y.
Published: April 2012

This study explores the boundary methods for the two‐dimensional homogeneous Stokes equations and investigates the particular solutions (PS) satisfying the Stokes equations. Smooth solutions for the Stokes equations are provided by explicit fundamental solutions (FS) and PS in this study, and singular corner solutions are also provided from linear elastostatics given in Li et al. ([Eng. Anal. Bound. Elem. 34 (2009), 533‐648, 2009). A new singularity model with an interior crack is proposed and solved by the collocation Trefftz method (CTM). The proposed method achieves highly accurate solutions with the first leading coefficient having 10 significant digits. These solutions may be used as a benchmark for testing results obtained by other numerical methods. Error bounds are derived for the CTM solutions using the PS. For a general corner, the exponent νk in r can only be obtained by numerical solutions of a system of nonlinear algebraic equations. Therefore, the combined method using many FS plus a few singular solutions is inevitable in most applications. For singularity problems, combining a few singular solutions with the FS is an advanced topic and is successfully implemented in Lee et al. (Eng. Anal. Bound. Elem. 24 (2010), 632–654); however, combining a few singular solutions with the smooth PS fails to converge in the first leading coefficient. As a result, the aforementioned method is not applicable to the singularity problems addressed in this article. With the help of particular and singular solutions, the hybrid Trefftz method with Lagrange multipliers can be developed for the Stokes equations. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
Association between congenital defects in papillary outgrowth and functional obstruction in Crim1 mutant mice
Authors: Wilkinson Lorine , Kurniawan Nyoman D , Phua Yu Leng , Nguyen Michael J , Li Joan , Galloway Graham J , Hashitani Hikaru , Lang Richard J , Little Melissa H
Published: April 2012

Crim1 hypomorphic (Crim1$^{KST264/KST264}$) mice display progressive renal disease characterized by glomerular defects, leaky peritubular vasculature, and progressive interstitial fibrosis. Here we show that 27% of these mice also present with hydronephrosis, suggesting obstructive nephropathy. Dynamic magnetic resonance imaging using Magnevist showed fast development of hypo‐intense signal in the kidneys of Crim1$^{KST264/KST264}$ mice, suggesting pooling of filtrate within the renal parenchyma. Rhodamine dextran (10 kDa) clearance was also delayed in Crim1$^{KST264/KST264}$ mice. Pyeloureteric peristalsis, while present, was less co‐ordinated in Crim1$^{KST264/KST264}$ mice. However, isolated renal pelvis preparations suggest normal pelvic smooth muscle contractile responses. An analysis of maturation during the immediate postnatal period [postnatal day (P) 0‐15] revealed defects in papillary extension in Crim1$^{KST264/KST264}$ mice. While Crim1 expression is weak in pelvic smooth muscle, strong expression is seen in the interstitium and loops of Henle of the extending papilla, commencing at the tip of the P1 papilla and disseminating throughout the papilla by P15. These results, as well as implicating Crim1 in papillary extension and pelvic smooth muscle contractility, highlight the previously unrecognized association between defects in papillary development and progression to chronic kidney disease later in life. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Influence of induced shear work on the properties of polyolefine nanocomposite pipes
Authors: Witschnigg Andreas , Laske Stephan , Kracalik Milan , Holzer Clemens
Published: April 2012

The use of layered silicates is steadily growing in polymer processing due to their great potential of enhancing material properties. Depending on the particle structure (agglomerated, intercalated, or exfoliated), a significantly higher level of improvement of the material properties can be achieved. The degree of exfoliation is exceedingly linked with the residence time and shear energy induced during processing. These processing parameters themselves are depending on the type of processing technique and conditions. The influence on exfoliation rate and the needed values for processing nanocomposites are not known precisely, but would be of major interest according to an optimization of mechanical and physical properties. In this work, the effect of different processing techniques (compounding, extrusion, and injection molding) on the dispersion of the nanofiller is investigated. A specific shear energy is calculated by the induced shear energy and the residence time regarding the mass throughput for better comparison. The differences in the degree of exfoliation according to dissimilarity of the chosen processing techniques are compared via various methods such as internal pressure creep rupture test, longitudinal shrinkage, and tensile test. It is shown that the calculated values are correlating with good precision, especially for the extrusion process. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Global efficiency of innovative rotational mold directly heated by thermal fluid
Authors: Monzón Mario D. , Bordón Pablo , Benítez Antonio N. , Kearns Mark , Hernández Pedro M. , Marrero María D.
Published: April 2012

The article is focused on analysis of global efficiency of new mold for rotational molding of plastic parts, being directly heated by thermal fluid. The overall efficiency is based on several items such as reduction of cycle time, better uniformity of heating–cooling and low energy consumption. The new tool takes advantage of additive fabrication and electroforming for making the optimal manifold and cavity shell of the mold. Experimental test of a prototype mold was carried out on an experimental rotational molding machine, developed for this purpose, measuring wall temperature, and internal air temperature, with and without plastic material inside. Results were compared with conventional mold heated into an oven and to theoretical simulations done by Computational Fluid Dynamic software (CFD). The analysis represents considerable improvement of cycle time related to conventional methods (heated by oven) and better thermal uniformity to conventional procedures by direct heating of oil with external channels. In addition to thermal analysis an energetic efficiency study was done. POLYM. ENG. SCI., 52:1998–2005, 2012. © 2012 Society of Plastics Engineers
The orientation of carbon nanotubes in poly(ethylene‐co‐octene) microcellular foaming and its suppression effect on cell coalescence
Authors: Zhai Wentao , Wang Jing , Chen Nan , Naguib Hani E. , Park Chul B.
Published: April 2012

Poly(ethylene‐co‐octene)/multiwall carbon nanotube (PEOc/MWNT) nanocomposites were prepared by a melt blending process. The MWNT's solubility and the transmission electron microscopy (TEM) observation indicated that the MWNT bonded well with a PEOc matrix. This facilitated the orientation of the MWNT when shear and extensional forces were applied to the nanocomposite melts. Microcellular PEOc/MWNT nanocomposite foams were prepared by a rising temperature process using supercritical CO2 as the blowing agent. Various foaming times were selected to reveal the cell‐structure evolution during the cell growth stage. The obvious cell opening, resulting from cell coalescence, was observed in the cell wall in the neat PEOc foams. When the MWNT was introduced, however, the MWNT tended to orient in the cell wall. Here, as a result of the strain hardening, it acted as a self‐reinforcing element, protecting the cells from destruction during cell growth. Consequently, a dramatic decrease in the open cell content and a still high cell density at long foaming times were obtained in the PEOc/MWNT nanocomposite foams. The present study provides experimental evidence of the vital effects of nanoparticle orientation on cell coalescence. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Solar cell generations over 40% efficiency
Authors: King R. R. , Bhusari D. , Larrabee D. , Liu X.‐Q. , Rehder E. , Edmondson K. , Cotal H. , Jones R. K. , Ermer J. H. , Fetzer C. M. , Law D. C. , Karam N. H.
Published: April 2012

Multijunction III‐V concentrator cells of several different types have demonstrated solar conversion efficiency over 40% since 2006, and represent the only third‐generation photovoltaic technology to enter commercial power generation markets so far. The next stage of solar cell efficiency improvement, from 40% to 50%‐efficient production cells, is perhaps the most important yet, since it is in this range that concentrator photovoltaic (CPV) systems can become the lowest cost option for solar electricity, competing with conventional power generation without government subsidies. The impact of 40% and 50% cell efficiency on cost‐effective geographic regions for CPV systems is calculated in the continental US, Europe, and North Africa. We take a systematic look at a progression of multijunction cell architectures that will take us up to 50% efficiency, using modeling grounded in well‐characterized solar cell materials systems of today's 40% cells, discussing the theoretical, materials science, and manufacturing considerations for the most promising approaches. The effects of varying solar spectrum and current balance on energy production in 4‐junction, 5‐junction, and 6‐junction terrestrial concentrator cells are shown to be noticeable, but are far outweighed by the increased efficiency of these advanced cell designs. Production efficiency distributions of the last five generations of terrestrial concentrator solar cells are discussed. Experimental results are shown for a highly manufacturable, upright metamorphic 3‐junction GaInP/GaInAs/Ge solar cell with 41.6% efficiency independently confirmed at 484 suns (48.4 W/cm2) (AM1.5D, ASTM G173‐03, 25 °C), the highest demonstrated for a cell of this type requiring a single metal‐organic vapor‐phase epitaxy growth run. Copyright © 2012 John Wiley & Sons, Ltd.
Thickness study of AZO films by RF sputtering in Ar + H2 atmosphere at room temperature
Authors: Zhu B. L. , Wang J. , Zhu S. J. , Wu J. , Zeng D. W. , Xie C. S.
Published: April 2012

Al‐doped ZnO (AZO) films were prepared on glass substrates by RF magnetron sputtering in an Ar + 5%H2 ambient at room temperature. The influence of film thickness (85–1101 nm) on the structural, electrical, and optical properties of the films was investigated. With increasing film thickness, it is found that the crystallinity of the films is improved and the surface roughness of the films increases. The decrease of resistivity is accompanied by an increase of carrier concentration and mobility. At the film thickness of 583–1101 nm, larger figures of merit (FOM) of the films can be obtained, in which the film with a thickness of 803 nm has the lowest resistivity of 3.13 × 10−4 Ω cm, a sheet resistance of 3.90 Ω/sq, and an average optical transmittance in the visible range of 80%. With increasing film thickness, the crystallite size, carrier concentration, and mobility of the films increase simultaneously, implying that the main scattering mechanism is the intercrystallite boundary scattering. It is found that the optical bandgap (Eg) increases from 3.50 to 3.72 eV with film thickness, and this increase can be ascribed to the Burstein–Moss (BM) effect after considering all possible effect factors. The results demonstrate that AZO films deposited in an Ar + H2 atmosphere at room temperature are suitable for application in thin‐film solar cells as transparent conductive electrode layers.
Pitfalls of electromagnetic tracking in clinical routine using multiple or adjacent sensors
Authors: Wegner Ingmar , Teber Dogu , Hadaschik Boris , Pahernik Sascha , Hohenfellner Markus , Meinzer Hans‐Peter , Huber Johannes
Published: April 2012

Background

While electromagnetic tracking (EMT) holds great promise, there are substantiated concerns about interference within the clinical environment. The purpose of this study was to address accuracy and isolate pitfalls for using multiple or adjacent EMT sensors in clinical routine.

Methods

A phantom simulating an EMT‐guided puncture of the kidney was used to analyse the effects of multiple sensors in the direct vicinity, common clinical environments and the influence of endo‐urological instruments.

Results

No relevant interference due to the investigated instruments was discovered. However, there was a great decrease in accuracy in the vicinity of a C‐arm's image intensifier, especially affecting the precision of two adjacent sensors.

Conclusion

Endo‐urological instruments can be safely used for multi‐sensor EMT‐guided procedures. When avoiding the immediate proximity of the surgical table and the image intensifier, there is a comfortable accuracy corridor. Thus, EMT‐assistance is promising for a wide range of procedures if basic conditions are met. Copyright © 2012 John Wiley & Sons, Ltd.
Intelligent tracking control of a dual‐arm wheeled mobile manipulator with dynamic uncertainties
Authors: Cheng Meng‐Bi , Su Wu‐Chung , Tsai Ching‐Chih , Nguyen Thang
Published: April 2012

This paper presents an intelligent control approach that incorporates sliding mode control (SMC) and fuzzy neural network (FNN) into the implementation of back‐stepping control for a path tracking problem of a dual‐arm wheeled mobile manipulator subject to dynamic uncertainties and nonholonomic constraints. By using the back‐stepping technique, the system equations are reformulated into two levels: the kinematic level and the dynamic level. A sliding manifold is constructed by considering the disturbance free kinematic level equations only. With all the system uncertainties concentrated in the dynamic level, an FNN controller associated with a switching type of control law is employed to enforce sliding mode on the prescribed manifold. All parameter adjustment rules for the proposed controller are derived from the Lyapunov theory such that uniform ultimate boundedness for both the tracking error and the FNN weighting updates is ensured. A simulation study, which compares different control design approaches, is included to illustrate the promise of the proposed SMC–FNN method. Copyright © 2012 John Wiley & Sons, Ltd.
Applying catastrophe theory to an information‐processing model of problem solving in science education
Authors: Stamovlasis Dimitrios , Tsaparlis Georgios
Published: April 2012

In this study, we test an information‐processing model (IPM) of problem solving in science education, namely the working memory overload model, by applying catastrophe theory. Changes in students' achievement were modeled as discontinuities within a cusp catastrophe model, where working memory capacity was implemented as asymmetry and the degree of field dependence/independence and logical thinking as bifurcation parameters. Data from achievement scores of high school students in nonalgorithmic problem solving (chemical, organic‐synthesis problems) were used and analyzed, using dynamic difference equations and statistical regression techniques. The dependent measure was the score difference in problems of varying demand from M = 3 to M = 8. The cusp catastrophe models proved superior (R2 = .73–.84) to the pre–post linear counterpart (R2 =.52–.66). The empirical evidence for the catastrophe effect supports the nonlinear model for the working memory overload hypothesis. The results add to research endeavors that built bridges between concepts of the theory of nonlinear dynamical systems and problem solving in science education, and to IPM as well. Finally, the theoretical and practical implications are discussed. © 2012 Wiley Periodicals, Inc. Sci Ed 96:392–410, 2012
A network perspective on organizational architecture: performance effects of the interplay of formal and informal organization
Authors: Soda Giuseppe , Zaheer Akbar
Published: April 2012

We take a network perspective to organizational architecture, conceptualizing it as multiple networks of both formal and informal interactions and argue that their interplay is key to better understanding individual organizational member performance. We develop and test the concept of network consistency as the overlap between the informal network of advice and information with formal structures and processes, expressed as networks. We theorize that consistency between formal and informal networks exerts differing effects on performance. We test our theory in a financial services firm, using secondary data to create formal networks and annual performance evaluations for our dependent variable, along with primary survey data from organizational members to obtain the informal advice and information network. Results support our network approach to organizational architecture. Copyright © 2012 John Wiley & Sons, Ltd.
The role of individuals in the information processing perspective
Authors: Turner Karynne L. , Makhija Mona V.
Published: April 2012

Researchers' primary concern with respect to the information processing perspective has been to understand how structural features influence the organization's ability to draw upon and utilize information for resolving problems, ignoring the primary role of individuals as the information processors within the organization. To shed light on this issue, we employ a quasi‐experimental design to examine the effects of two structural types, organic and mechanistic, on individuals' gathering, interpretation, and synthesis of information and, in turn, their problem‐solving orientation. Holding the external context constant, our evidence shows that individuals do process information differently under the two structural types, which then leads to different comfort levels in dealing with organizational problems. These findings highlight the importance of considering the microfoundations of the information processing perspective. Copyright © 2012 John Wiley & Sons, Ltd.
Inhibition of polyisoprenylated methylated protein methyl esterase by synthetic musks induces cell degeneration
Authors: Ayuk‐Takem Lambert , Amissah Felix , Aguilar Byron J. , Lamango Nazarius S.
Published: April 2012

Synthetic fragrances are persistent environmental pollutants that tend to bioaccumulate in animal tissues. They are widely used in personal care products and cleaning agents. Worldwide production of Galaxolide and Tonalide are in excess of 4500 tons annually. Because of their widespread production and use, they have been detected in surface waters and fish in the US and Europe. Consumption of contaminated water and fish from such sources leads to bioaccumulation and eventual toxicity. Since fragrances and flavors bear structural similarities to polyisoprenes, it was of interest to determine whether toxicity by Galaxolide and Tonalide may be linked with polyisoprenylated methylated protein methyl esterase (PMPMEase) inhibition. A concentration‐dependent study of PMPMEase inhibition by Galaxolide and Tonalide as well as their effects on the degeneration of cultured cells were conducted. Galaxolide and Tonalide inhibited purified porcine liver PMPMEase with Ki values of 11 and 14 μM, respectively. Galaxolide and Tonalide also induced human cancer cell degeneration with EC50 values of 26 and 98 μM (neuroblastoma SH‐SY5Y cells) and 58 and 14 μM (lung cancer A549 cells), respectively. The effects on cell viability correlate well with the inhibition of PMPMEase activity in the cultured cells. Molecular docking analysis revealed that the binding interactions are most likely between the fragrance molecules and hydrophobic amino acids in the active site of the enzyme. These results appear to suggest that the reported neurotoxicity of these compounds may be associated with their inhibition of PMPMEase. Exposure to fragrances may pose a significant risk to individuals predisposed to developing degenerative disorders. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 466–477, 2014.
Primary cilia and graded Sonic Hedgehog signaling
Authors: Sasai Noriaki , Briscoe James
Published: April 2012

Cilia are evolutionary‐conserved microtubule‐containing organelles protruding from the surface of cells. They are classified into two types—primary and motile cilia. Primary cilia are nearly ubiquitous, at least in vertebrate cells, and it has become apparent that they play an essential role in the intracellular transduction of a range of stimuli. Most notable among these is Sonic Hedgehog. In this article we briefly summarize the structure and biogenesis of primary cilia. We discuss the evidence implicating cilia in the transduction of extrinsic signals. We focus on the involvement and molecular mechanism of cilia in signaling by Sonic Hedgehog in embryonic tissues, specifically the neural tube, and we discuss how cilia play an active role in the interpretation of gradients of Sonic Hedgehog (Shh) signaling. WIREs Dev Biol 2012. doi: 10.1002/wdev.43

For further resources related to this article, please visit the WIREs website.
Anxiety and pain during bone marrow aspiration and biopsy
Authors: Kuivalainen Anna-Maria , Pitkäniemi Janne , Widenius Tom , Elonen Erkki , Rosenberg Per
Published: April 2012

Background

Previously we found that pre-procedural nervousness and tension (translated into English as “anxiety”), assessed on a non-validated five-point scale, correlated with pain intensity of the various stages of bone marrow aspiration and biopsy (BMAB). The fewer the previous BMAB procedures the stronger the pain from a repeated procedure. The primary purpose of the present observational study is to evaluate the state of anxiety just before BMAB and to find out whether it affects the pain experiences during the various stages of the BMAB procedure. We also examined whether first-timers differ from patients with previous BMAB experience in the degree of anxiety and intensity of BMAB procedural pain.

Methods

A total of 166 adult outpatients undergoing the BMAB from the Helsinki University Hospital were enrolled, 48 of them being first-timers. The level of anxiety was measured with State-Trait Anxiety Inventory (STAI) and the pain experiences associated with the various stages of the procedure were evaluated on the NRS-scale (Numeral Rating Scale 0-10) and using the Finnish pain vocabulary. BMAB was planned to be performed under lidocaine infiltration anaesthesia but, on request, patients were allowed to receive premedication with diazepam orally or alfentanil i.m. If, in spite of supplemental local anaesthetic the patient still felt pain from the sampling needle tip, i.m. alfentanil was administered.

Results

There was a clear association between anxiety and pain during all stages of the procedure, except during biopsy. The NRS scores varied from 0 to 10 in all the various stages of BMAB. The first-timers did not differ from the more experienced patients with regard to pain experiences; only the pain felt during the local anaesthetic infiltration was milder (P = 0.007) in first-timers than in the others. Procedural pain in those who were given analgesic or sedative premedication was similar (P < 0.05) to that in the non-premedicated patients. The words characterizing the pain of the various stages belonged to a major extent (76-90%) to the sensory class of words.

Conclusion

Pre-procedural anxiety had a major impact on the pain ratings. The first-timers and patients with previous experience of BMAB had a similar degree of pre-procedural anxiety, as well as of the intensity of procedural pain, except that infiltration of local anaesthetic was less painful in the first-timers.

Implications

Identification of anxious (fearful) patients prior to BMAB, and premedicating them individually may improve satisfaction in both patient and caregiver.
A (MAINLY EPISTEMIC) CASE FOR MULTIPLE-VOTE MAJORITY RULE
Authors: Bradley Richard , Thompson Christopher
Published: April 2012

Multiple-vote majority rule is a procedure for making group decisions in which individuals weight their votes on issues in accordance with how competent they are on them. When individuals are motivated by the truth and know their relative competence on different issues, multiple-vote majority rule performs nearly as well, epistemically speaking, as rule by an expert oligarchy, but is still acceptable from the point of view of equal participation in the political process.
Effect of dairy powder rehydration state on gel formation during yogurt process
Authors: Karam Marie Celeste , Gaiani Claire , Barbar Reine , Hosri Chadi , Scher Joel
Published: April 2012

Protein fortification and solubilisation into the milk base are important parameters enhancing yogurt texture. In this study, the milk base prepared from reconstituted skim milk powder was fortified with 2% of ‘aged’ (1 year old) or ‘fresh’ micellar casein (MC) powder. Micellar casein powders were left to rehydrate at 20°C for different times (5 or 180, 300, 480, 900 or 1440 min) before acidification with glucono-delta-lactone. The rehydration of the MC powders into milk was monitored with a granulo-morphometer equipment, thus, for the first time, allowing the elucidation of MC rehydration process into an opaque environment such as milk. Whereas the gel point was delayed proportionally to the powder rehydration length, the storage modulus appears unaffected. Besides, the gelation onset was not altered by the powder age.
Measuring the effects of alexithymia on perception of emotional vocalizations in autistic spectrum disorder and typical development
Authors: Heaton P. , Reichenbacher L. , Sauter D. , Allen R. , Scott S. , Hill E.
Published: April 2012

Background

The results from recent studies suggest that alexithymia, a disorder characterized by impairments in understanding personal experiences of emotion, is frequently co-morbid with autism spectrum disorder (ASD). However, the extent that alexithymia is associated with primary deficits in recognizing external emotional cues, characteristic in ASD, has yet to be determined.

Method

Twenty high-functioning adults with ASD and 20 age- and intelligence-matched typical controls categorized vocal and verbal expressions of emotion and completed an alexithymia assessment.

Results

Emotion recognition scores in the ASD group were significantly poorer than in the control group and performance was influenced by the severity of alexithymia and the psycho-acoustic complexity of the presented stimuli. For controls, the effect of complexity was significantly smaller than for the ASD group, although the association between total emotion recognition scores and alexithymia was still strong.

Conclusions

Higher levels of alexithymia in the ASD group accounted for some, but not all, of the group difference in emotion recognition ability. However, alexithymia was insufficient to explain the different sensitivities of the two groups to the effects of psycho-acoustic complexity on performance. The results showing strong associations between emotion recognition and alexithymia scores in controls suggest a potential explanation for variability in emotion recognition in non-clinical populations.
El Güegüence, post-Sandinista Nicaragua, and the Resistant Politics of Dancing
Authors: Westlake E. J.
Published: April 2012

Folk dance fulfills a particular function in the survival of communal memory. Community history and identity live through the animated body. But in the case of El Güegüence, Nicaragua's hybrid Spanish-Nahuatl dance-drama, many feel it is a contested tradition with a contested set of significations. Within that contestation, communal memory is fractured and ruptured in ways that produce a unique and dynamic discourse.

In this paper, I will focus on Irene López's reworking of El Güegüence as the dance piece El Gran picaro. López has been criticized for altering the “authentic” dance tradition, a criticism she answers by pointing out that the original dance was lost when only the artifact of the dramatic text was preserved. López's reworking functions as collective memory and as an act of restored tradition, an invention meant to stand in for the original as faithfully as the inventor can imagine.

I will also examine the redeployment of El Güegüence by groups who have embraced the figure and the act of dancing the masked drama as an expression of the subaltern, the marginalized, and the closeted minority identities within the context of the national culture, specifically Grupo Relajo, with its playful workshops built around the popular story. Ultimately, El Güegüence represents an artifact of the erasure of dance and, by extension, the indigenous body. Both López and Grupo Relajo, through their staging, resurrect the body of the indigenous Other and create a vehicle for the body to move in resistance to such erasure.
PUBLIC INFRASTRUCTURE AND EXTERNALITIES IN U.S. MANUFACTURING: EVIDENCE FROM THE PRICE-AUGMENTING AIM COST FUNCTION
Authors: Feng Guohua , Serletis Apostolos
Published: April 2012

In this paper, we propose a price-augmenting asymptotically ideal model (AIM) cost function to investigate the effects of public infrastructure on the performance of the U.S. manufacturing industry, using KLEMS data over the period from 1953 to 2001. In doing so, we make a distinction between the productivity effect and the production factor effect of public infrastructure. This distinction allows us to focus on the more interesting productivity effect by incorporating public infrastructure into the AIM cost function through the efficiency index. Moreover, we specify the growth rate of the efficiency index as a Box–Cox function of public infrastructure and a time trend, a proxy for other technology. The excellent flexibility of our price-augmenting AIM cost function offers many insights regarding the effects of infrastructure on the U.S. manufacturing sector.
Cerebrospinal fluid 5-hydroxyindolacetic acid correlates directly with negative affective intensity, but not affective lability, in human subjects
Authors: Coccaro Emil F. , Boparai Anjiwan , Lee Royce
Published: April 2012

Centrally acting monoamines have long been thought to be associated with component traits of behavior and emotion and are potential biological mediators of psychopathology. In this study we tested the hypothesis that centrally acting monoamines would be associated with measures of affective instability (i.e. affective intensity and affective lability) in healthy and personality disordered human subjects. In total, 57 adult subjects including 19 psychiatrically healthy volunteers and 38 personality disordered individuals were assessed for affective instability with the affective intensity measure (AIM) and the Affective Lability Scale (ALS). Samples of cerebrospinal fluid (CSF) were collected for assay of 5-hydroxyindoleacitic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxy-phenylglycol (MHPG). CSF 5-HIAA concentration correlated directly with overall AIM score and, specifically, with the AIM Negative Intensity score, in all subjects and in personality disordered subjects. This result was not affected but the addition of aggression scores or life history of mood disorder to the model. Neither CSF HVA nor MHPG were found to uniquely correlate with either AIM or ALS measure. Higher Affective Intensity scores, Negative Intensity scores, specifically, are directly correlated with higher basal levels of CSF 5-HIAA. This relationship was independent of aggression, life history of mood disorder and general personality traits.
A variant of the neuronal amino acid transporter SLC6A15 is associated with ACTH and cortisol responses and cognitive performance in unipolar depression
Authors: Schuhmacher Anna , Lennertz Leonhard , Wagner Michael , Höfels Susanne , Pfeiffer Ute , Guttenthaler Vera , Maier Wolfgang , Zobel Astrid , Mössner Rainald
Published: April 2012

Major depressive disorder (MDD) is accompanied by both cognitive impairments and a hyperactivity of the hypothalamic–pituitary–adrenocortical (HPA) system, resulting in an enhanced glucocorticoid secretion. Cortisol acts via mineralocorticoid and glucocorticoid receptors densely located in the hippocampus, a brain area that is important regarding cognitive functions and especially memory functions. Recently, a variant (rs1545843) affecting transcription of the human SLC6A15 gene has been associated with depression in a genome-wide association study. In an animal model, the neuronal amino acid transporter SLC6A15 was found to be decreased in stress-susceptible mice. Against the background of stress impacting on the activity of the HPA axis, we have investigated alterations of adrenocorticotropic hormone (ACTH) and cortisol secretion in the combined dexamethasone/corticotrophin-releasing hormone (Dex/CRH) test as well as memory and attention performance in a sample of 248 patients with unipolar depression and 172 healthy control subjects genotyped for rs1545843. MDD patients carrying the depression-associated AA genotype showed enhanced maximum and area under the curve ACTH and cortisol answers (p = 0.03) as well as an impaired memory and impaired sustained attention performance (p = 0.04) compared to carriers of at least one G allele. No effects of the SLC6A15 variant were found in the healthy control group. Our findings argue for a role of the SLC6A15 gene in ACTH and cortisol secretion during the Dex/CRH test and furthermore in the occurrence of cognitive impairments in unipolar depression.