bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autoregulation of Musashi1 mRNA translation during Xenopus oocyte maturation
Authors: Arumugam Karthik , MacNicol Melanie C. , MacNicol Angus M. 
Published: June 2012

AbstractThe mRNA translational control protein, Musashi, plays a critical role in cell fate determination through sequence‐specific interactions with select target mRNAs. In proliferating stem cells, Musashi exerts repression of target mRNAs to promote cell cycle progression. During stem cell differentiation, Musashi target mRNAs are de‐repressed and translated. Recently, we have reported an obligatory requirement for Musashi to direct translational activation of target mRNAs during Xenopus oocyte meiotic cell cycle progression. Despite the importance of Musashi in cell cycle regulation, only a few target mRNAs have been fully characterized. In this study, we report the identification and characterization of a new Musashi target mRNA in Xenopus oocytes. We demonstrate that progesterone‐stimulated translational activation of the Xenopus Musashi1 mRNA is regulated through a functional Musashi binding element (MBE) in the Musashi1 mRNA 3′ untranslated region (3′ UTR). Mutational disruption of the MBE prevented translational activation of Musashi1 mRNA and its interaction with Musashi protein. Further, elimination of Musashi function through microinjection of inhibitory antisense oligonucleotides prevented progesterone‐induced polyadenylation and translation of the endogenous Musashi1 mRNA. Thus, Xenopus Musashi proteins regulate translation of the Musashi1 mRNA during oocyte maturation. Our results indicate that the hierarchy of sequential and dependent mRNA translational control programs involved in directing progression through meiosis are reinforced by an intricate series of nested, positive feedback loops, including Musashi mRNA translational autoregulation. These autoregulatory positive feedback loops serve to amplify a weak initiating signal into a robust commitment for the oocyte to progress through the cell cycle and become competent for fertilization.Mol. Reprod. Dev. 79: 553‐563, 2012. © 2012 Wiley Periodicals, Inc.
Spatial aspects of member retention, participation and co‐creation in tourism settings
Authors: Olsson Anna Karin 
Published: June 2012

Many customers today belong to a number of different membership programs. Memberships have been applied in different ways in tourism settings since the 1970s. Gradually memberships have developed from merely rewarding loyal or frequent customers into building long‐term relationships generating mutual value. Membership programs are of increasing importance as competitive marketing tools. Membership bases are often geographically dispersed as membership organizations attract members living in various locations. This study focuses on member behaviours as interactions within a membership relationship. The influence of distance on member behaviours such as retention, participation, and co‐creation is studied. A survey of 755 members was conducted at a major Swedish nonprofit tourist attraction. Findings indicate that member behaviours such as supporting, visiting, use of member information channels, recruiting new members, performing volunteer work, sense of doing something good, and to get appreciation of member work show significant differences depending on how far away members live. Further studies of members are needed to find ways of developing memberships as strategic resources and especially member interactions as important innovative elements in performance and competition in tourism settings.Copyright © 2012 John Wiley & Sons, Ltd.
Prediction of fiber orientation in the injection molding of long fiber suspensions
Authors: Ortman Kevin , Baird Donald , Wapperom Peter , Aning Alex 
Published: June 2012

AbstractThe properties of long glass fiber reinforced parts are highly dependent on the fiber orientation generated during processing. In this research, the orientation of concentrated long glass fibers generated during the filling stage of a center‐gated disk (CGD) mold was simulated. The orientation of the fibers was calculated using both the Folgar‐Tucker model and a recently developed semiflexible Bead‐Rod model. Rheologically consistent model parameters were used in these simulations, as determined from a previously proposed method, using a sliding plate rheometer and newly modified stress theory. The predicted CGD orientations were compared with experimentally measured values obtained from the parts. Both models performed very well when using model parameters consistent with the independent rheological study, and the results provide encouragement for the proposed method. Comparatively, the Folgar‐Tucker model provided slightly better orientation predictions up to 20% of the fill radius, but above 20% the Bead‐Rod model predicted better values of the orientation in both the radial and circumferential directions. The Folgar‐Tucker model, however, provided better orientation values perpendicular to the flow direction. Lastly, both models only qualitatively represented the orientation above 70% of the fill radius where frontal flow effects were suspected to be non‐negligible. The uniqueness of this research rests on a method for obtaining model parameters needed to predict fiber orientation which are independent of the experiments being simulated and a method for handling long semiflexible fiber suspensions. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Impact of laterally non‐uniform carrier lifetime on photoconductance‐based lifetime measurements with self‐consistent calibration
Authors: Liang W. S. , Weber Klaus J. , Ren Y. L. 
Published: June 2012

ABSTRACTThe impact of laterally non‐uniform carrier lifetime on the determination of the lifetime from photoconductance‐based measurements, based on the self‐consistent method proposed by Trupke and Bardos, is investigated using a simple model. It is shown that the method can result in an overestimation of the mean lifetime, with the magnitude of the error mainly dependent on the distribution of the effective lifetime across the area sensed by the photoconductance coil. Although in many cases the error introduced will be relatively small (in the order of 5% or less), much larger errors can result in some cases, such as for samples that feature small areas with a significantly higher than average lifetime. The error can be eliminated through independent measurement of the sample optical properties. Experimental measurements confirm the model predictions. Copyright © 2012 John Wiley & Sons, Ltd.
A theoretical analysis of substituted aromatic compounds
Authors: Bhavaraju Manikanthan , Gwaltney Steven R. 
Published: June 2012

AbstractThe substituents CH3, F, NO2, OCH3, and CH2CH2 were placed at the ortho, meta, and para positions on the aromatic molecules aniline, benzaldehdye, nitrobenzene, and phenol. MMFF94, AM1, B3LYP, M06, M06‐2X, ωB97X, ωB97X‐d, and RI‐MP2 using cc‐pVDZ and cc‐pVTZ and CCSD(T) with cc‐pVDZ basis sets were used to calculate the geometries and energies of all regiomers of the molecules. Relative energies of the ortho and meta regiomers relative to the para regiomers were calculated and compared to the CCSD(T) values. A good basis set correlation between cc‐pVDZ and cc‐pVTZ was observed in RI‐MP2. Overall, RI‐MP2 gave the best correlation with the CCSD(T) results. All of the hybrid functionals showed similar accuracy and could effectively describe the intramolecular hydrogen‐bonding interactions of these compounds. The methoxy group at the para position in methoxyaniline, methoxyphenol, methoxynitrobenzene, and methoxybenzaldehyde was rotated around the phenyl‐O bond. HF, along with the cc‐pVDZ basis with the other methods, generated inaccurate energy profiles for p‐methoxyphenol. For the density functional theory methods, it was necessary to use improved grids to get smooth curves. © 2013 Wiley Periodicals, Inc.
Reaction mechanism of hydrogenation and direct desulfurization routes of dibenzothiophene‐like compounds: A density functional theory study
Authors: Valencia Diego , Peña Laura , García‐Cruz Isidoro 
Published: June 2012

AbstractReaction mechanisms of the two distinct routes, namely hydrogenation (HYD) and direct desulfurization (DDS), of dibenzothiophene (DBT)‐type compounds in hydrodesulfurization (HDS) process have been investigated by means of density functional theory (DFT). A series of methyl‐ and dimethyl‐compounds substituted at different positions in DBT were compared to get a deeper insight into the electronic effects of the alkyl position substitution. The Gibbs energy of reaction for each route and the CS bond energies were calculated. The calculations showed that HYD route is more exergonic than DDS route. Refractory compounds exhibited less reaction energy values and high CS bond stability. Full chemical structures in the energetic profile of HYD and DDS routes were identified. We proposed a reaction mechanism for each HDS route based on our theoretical calculations. According to our proposed mechanisms, the HYD reaction route is favored compared to DDS reaction route because energetic barriers are higher on the DDS route. The effect of methyl groups is clearly observed. Refractory compounds have higher activation and lower formation energies. This systematic study trough DFT method provides an important contribution in the field of HDS because the proposed mechanisms are related with some experimental observations. © 2012 Wiley Periodicals, Inc.
Identification of structurally diverse alkaloids in Corydalis species by liquid chromatography/electrospray ionization tandem mass spectrometry
Authors: Jeong Eun‐Kyung , Lee Sun Young , Yu Se Mi , Park Na Hyun , Lee Hyun‐Seok , Yim Yong‐Hyeon , Hwang Geum‐Sook , Cheong Chaejoon , Jung Jee H. , Hong Jongki 
Published: June 2012

RATIONALEAlkaloids with significant therapeutic effects are the main active constituents of Corydalis (C.) species. There are several kinds of alkaloids in C. species associated with diverse alkaloid metabolism in plants, but they are rarely identified. This study aimed to identify diverse alkaloids in C. species by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS).METHODSSeveral types of alkaloids were extracted from C. species using ultrasonication with 70% CH3OH, and the extract was partitioned at pH 2 and 12. Separation of alkaloids was achieved by C18 high‐performance liquid chromatography (HPLC), and MS/MS analysis was conducted by electrospray ionization triple‐quadrupole mass spectrometry. For further confirmation, LC/Fourier transform ion cyclotron resonance (FTICR)‐MS was used to obtain accurate mass data and gas chromatography (GC)/MS combined with trimethylsilyl derivatization was applied for identification of the minor alkaloids.RESULTSThirty‐three alkaloids among three different C. species were successfully separated and identified by LC/ESI‐MS/MS and LC/FTICR‐MS. Structural assignment of individual alkaloids was performed according to MS/MS spectral patterns. For further confirmation, accurate mass data of alkaloids by LC/FTICR‐MS were obtained within 5 ppm and the GC/MS data for the trimethylsilyl alkaloids were also obtained. Among 33 alkaloids identified from this study, 13 alkaloids were reported for the first time in the investigated C. species.CONCLUSIONSThe LC/ESI‐MS/MS technique was effective in obtaining structural information and yielded diagnostic ions for diverse alkaloids. Based on the identified 33 alkaloids, marker compounds were suggested for the three C. species with different geographic origins. This study may also be useful for elucidating unknown alkaloids in herbal medicines. Copyright © 2012 John Wiley & Sons, Ltd.
An exploratory study of international strategic choices for exporting firms in Nigeria
Authors: Okpara John O. 
Published: June 2012

AbstractInternational markets offer potential opportunities for small and medium‐sized enterprises (SMEs) in developing markets in terms of export growth and performance. Notwithstanding these benefits, many SMEs in Nigeria have not initiated exports or have faced problems in competing in the export markets. The aim of this article is to examine strategic choices available for SME exporting firms in Nigeria. Results of data analysis revealed that the three types of strategy orientations pursued by firms for dealing with competition in export markets are low cost, differentiation, and differentiation focus strategies. Findings also showed that low cost and differentiation strategies are significantly and positively related to export performance. © 2012 Wiley Periodicals, Inc.
Evaluating the contribution of the export sector to real GDP growth rate under structural adjustment programme (SAP): The case of Ghana
Authors: Mmieh Frederick , Owusu‐Frimpong Nana , Mordi Chima 
Published: June 2012

AbstractThis study evaluates the contribution of the export sector to real gross domestic product (GDP) growth rate in the past eight years in Ghana. First, it reviews the main economic policy adopted by the government from 1983 to 2007 to reverse the postindependence economic decline of the Ghanaian economy. Second, it assesses the extent to which the continued reform agenda has facilitated the growth of the export sector during 2000–2007. Third, it presents an evaluation of the contribution of the performance of the export sector as a major stimulus to economic growth. Documentary analysis of available evidence reveals that the implementation of the Structural Adjustment Programme (SAP) has led to a positive export sector performance and subsequent real GDP growth rates during the period under review. However, this study argues that there is little aggregate evidence that the trade policy reforms and liberalization since the late 1980s have produced a very significant export response. Exports have not increased consistently and imports have tended to grow faster than exports following liberalization widening the trade deficit and thus constraining growth. © 2012 Wiley Periodicals, Inc.
Mechanical properties of silicon nanowires
Authors: Furmanchuk Al'ona , Isayev Olexandr , Dinadayalane Tandabany C. , Leszczynska Danuta , Leszczynski Jerzy 
Published: June 2012

AbstractSilicon nanowires (SiNWs) are at the top of the list of materials used in conventional electromechanical devices as well as in strained nanotechnology. Both experimental and theoretical studies showed the size‐dependent character of mechanical properties of SiNWs. However, the surface contaminations, local surface strains, ‘boundary conditions’, native oxide, equipment‐induced errors, and the errors caused by postprocessing of results lead to softening of Young's modulus and extension of the region where the size dependency is seen by experimentalists. Application of improved potentials or advanced theoretical modeling such as inclusion of explicit treatment of temperature and quantum‐mechanical effects allows to show specificity of Young's modulus to the size and shape in case of small (width <4 nm) nanowires. The ductile‐brittle transitions of SiNWs at different temperatures are revealed. Some suggestions on postprocessing techniques are discussed. © 2012 John Wiley & Sons, Ltd.This article is categorized under:

Structure and Mechanism > Molecular Structures
Three factors in the design and acquisition of language
Authors: O'Grady William 
Published: June 2012

AbstractRecent advances in linguistic theory offer new proposals about the factors that are crucial to understanding the design and acquisition of language—the genetic endowment, experience, and principles not specific to the language faculty. Of particular interest is the third of these factors, whose importance is now widely recognized, raising questions about its character, its role in shaping the language faculty, and its impact on the future of linguistic research.WIREs Cogn Sci2012 doi: 10.1002/wcs.1188This article is categorized under:Linguistics > Language Acquisition
Tutorial on biological networks
Authors: Vital‐Lopez Francisco G. , Memišević Vesna , Dutta Bhaskar 
Published: June 2012

AbstractUnderstanding how the functioning of a biological system emerges from the interactions among its components is a long‐standing goal of network science. Fomented by developments in high‐throughput technologies to characterize biomolecules and their interactions, network science has emerged as one of the fastest growing areas in computational and systems biology research. Although the number of research and review articles on different aspects of network science is increasing, updated resources that provide a broad, yet concise, review of this area in the context of systems biology are few. The objective of this article is to provide an overview of the research on biological networks to a general audience, who have some knowledge of biology and statistics, but are not necessarily familiar with this research field. Based on the different aspects of network science research, the article is broadly divided into four sections: (1) network construction, (2) topological analysis, (3) network and data integration, and (4) visualization tools. We specifically focused on the most widely studied types of biological networks, which are, metabolic, gene regulatory, protein–protein interaction, genetic interaction, and signaling networks. In future, with further developments on experimental and computational methods, we expect that the analysis of biological networks will assume a leading role in basic and translational research. © 2012 Wiley Periodicals, Inc.This article is categorized under:

Algorithmic Development > Biological Data Mining
Application Areas > Data Mining Software Tools
Application Areas > Science and Technology
Laparoscopic Common Bile Duct Exploration in Patients with Complicated Cholecystitis: a Safety and Feasibility Study
Authors: Lo Hung‐Chieh , Wang Yu‐Chun , Huang Jui‐Chien , Hsu Cheng‐Hsiung , Wu Shih‐Chi , Hsieh Chi‐Hsun 
Published: June 2012

AbstractBackgroundLaparoscopic cholecystectomy (LC) with common bile duct exploration (LCBDE) is nowadays a preferred one‐stage treatment. However, the influence of complicated cholecystitis (CC) on LCBDE has rarely been addressed. In the present study we aimed to verify whether severe gallbladder inflammation would adversely affect the outcome of LCBDE.Material and methodsFrom 2008 to 2011, all patients undergoing LC and LCBDE at China Medical University Hospital were included. Patients were divided into two groups based on the severity of cholecystitis. Those with unstable hemodynamics and co‐morbidities who were deemed unfit for general anesthesia were excluded. Patient demographics, surgical results, and outcome were compared between the groups.ResultsDuring the study period, 117 patients diagnosed with cholecystitis were found to have common bile duct (CBD) stones and underwent LC + LCBDE. Of these 117 patients, 87 had uncomplicated cholecystitis (UC) and the remaining 30 patients had CC. There was no demographic difference between the groups, but for patients with CC there were marginally longer operative times (190 vs. 223 min, p = 0.141), more blood loss (10 vs. 150 ml, p < 0.05), and longer postoperative hospital stays (6 vs. 7 days, p < 0.05). The risk of developing major intraoperative complications was not greater for those with CC. Conversion to open cholecystectomy was necessary in a total of 12 cases (10 %) with an overall 1 % mortality rate.ConclusionsComplicated cholecystitis was not a contraindication for LCBDE. Complete stone clearance can be achieved in a substantial number of cases with an acceptable complication rate. Further prospective randomized studies are required to validate its long‐term safety.
Primary obturator-muscle pyomyositis in immunocompetent children
Authors: García-Mata Serafín , Hidalgo-Ovejero Angel , Esparza-Estaun Joaquín 
Published: June 2012

Purpose Primary pyomyositis in immunocompetent children in non-tropical regions (countries with temperate climates) is very uncommon. It is rarely found in the intrapelvic muscles, and even more rarely in the obturator muscles. We try to draw attention to the potential occurrence in these conditions. Methods Five new cases of primary obturator-muscle pyomyositis in immunocompetent children aged between 6 and 11 years in a temperate climate are presented. They present with symptoms as follows: fever, pain (thigh, abdominal, inguinal, and/or hip pain), and limp. Three of them had no hip movement limitation. All of them had tenderness in the perineum zone. Results Laboratory tests may reveal high erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) counts, but depend on the length of diagnostic delay. The evolution time oscillated from 1 to 5 days. Fever and limp disappearance depends on the evolution time previous to the onset of the antibiotics administration. In 4 out of 5 patients, Staphylococcus aureus was present in the blood cultures. In all cases of obturator-muscle pyomyositis, diagnosis was confirmed using computed tomography (CT) scan (one) and/or magnetic resonance imaging (MRI) (four). Conclusions Obturator-muscle pyomyositis is aimed at emphasizing the diagnostic difficulties associated with the condition, due to its deep location and to the fact that the disease presents with multiple manifestations that may initially cause confusion, since they mimic other conditions occurring in the abdomen, hip (septic arthritis, osteomyelitis), spine, etc. The diagnosis is only confirmed using CT scan and/or MRI. In the five patients with antibiotics treatment, the condition resolves without sequelae, even at long-term follow-up.
Are the sunspots really vanishing?
Authors: Clette Frédéric , Lefèvre Laure 
Published: June 2012

Context:The elapsed solar cycle (23) ended with an exceptionally long period of low activity and with unprecedented low levels for various series of solar irradiance and particle flux measurements. This unpredicted evolution of solar activity raised multiple questions about a future decline of the solar cycles and launched a quest for precursor signs of this possible deep solar transition over the last decade.Aim:We present here a review and overall interpretation of most current diagnostics of solar cycle 23, including the recent disagreements that appeared among solar reference indices and standard solar-based geo-indices, the indication of a changed pattern of internal torsional waves (helioseismology) or the announced fading and magnetic weakening of sunspots.Methods:Based on a statistical analysis of detailed sunspot properties over the last 24 years, we complete the picture with new evidence of a strong global deficit of the smallest sunspots starting around 2000, in order to answer the question: are all sunspots about to disappear?Results:This global scale-dependent change in sunspot properties is confirmed to be real and not due to uncontrolled biases in some of the indices. It can also explain the recent discrepancies between solar indices by their different sensitivities to small and weak magnetic elements (small spots). The International Sunspot IndexRi, based on unweighted sunspot counts, proved to be particularly sensitive to this particular small-scale solar evolution.Conclusions:Our results and interpretation show the necessity to look backwards in time, more than 80 years ago. Indeed, the Sun seems to be actually returning to a past and hardly explored activity regime ending before the 1955–1995 Grand Maximum, which probably biased our current space-age view of solar activity.