bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of distance with the nanoscale precise imaging by rapid beam oscillation method
Authors: Lanzano Luca , Gratton Enrico 
Published: April 2012

AbstractWe discuss here the principles of a novel optical method in which the scanning of a laser spot around a fluorescent object is used to determine its shape, orientation, and fluorophore distribution. The scanning pattern is adapted to the shape of the object according to a feedback principle based on intensity modulation measurements. The modulation of the intensity with respect to the angular coordinate is used to keep the orbit centered on the object. The modulation induced by rapid oscillations of the orbit radius is used to measure the local distance from the surface with nanometer precision. We provide a model to describe the fundamental relationship between modulation and distance and discuss the range of validity of several approximate expressions. According to this model, the distance can be measured with a precision dependent on the steepness of the point spread function and the total number of detected photons. To test our findings, we performed experiments with one or two channels on fluorescent spheres of known size and characterized the modulation function of our microscope setup. We conclude that the method can be used to measure distances in the range 10–200 nm between two surfaces labeled with two different probes. Microsc. Res. Tech. 75:1253–1264, 2012. © 2012 Wiley Periodicals, Inc.
Microscopic vision based on the adaptive positioning of the camera coordinate frame
Authors: Zhang Guangjun , Li Weixian , Wei Zhenzhong , Cao Zhipeng , Wang Yali 
Published: April 2012

AbstractMicroscopic vision measurement precision has been largely limited by inaccurately calibrated model parameters, because image plane is near parallel to reference plane in the narrow depth of field. This article proposes a method of precise microscopic vision measurement based on the adaptive positioning of the camera coordinate frame. The microscopic vision measurement movably attaches the origin of the camera coordinate frame along the optical axis. By finding the optimal position, the nonlinearity of the objective function in calibration optimization is decreased and the optimization sensitivity to initial values is reduced. Therefore, we obtain a high calibration precision and eventually ensure a high measurement precision. Mathematical simulations illustrate that the calibration precision of the proposed microscopic vision measurement model is higher than that of the conventional vision measurement model. The experiment shows that with magnification of 3.024×, the presented system achieves a precision of 0.12% based on the proposed microscopic vision measurement model, which is two times higher than the one based on the conventional vision measurement model. Microsc. Res. Tech. 75:1281–1291, 2012. © 2012 Wiley Periodicals, Inc.
Sequential differentiation of mesenchymal stem cells in an agarose scaffold promotes a physis‐like zonal alignment of chondrocytes
Authors: Schmitt Jacqueline Frida , Hua See Kwee , Zheng Yang , Po James Hui Hoi , Hin Lee Eng 
Published: April 2012

AbstractChondrocytes of the epiphyseal growth plate (physis) differentiate and mature in defined linear zones. The current study examines the differentiation of human bone marrow derived mesenchymal stem cells (hBMSCs) into zonal physeal cartilage. hBMSCs were embedded in an agarose scaffold with only the surface of the scaffold in direct contact with the culture medium. The cells were differentiated using a two‐step system involving the sequential addition of TGFβ followed by BMP2. The resultant samples displayed a heterogenic population of physis‐like collagen type 2 positive cells including proliferating chondrocytes and mature chondrocytes showing hypertrophy, expression of early bone markers and matrix mineralization. Histological analysis revealed a physis‐like linear zonal alignment of chondrocytes in varying stages of differentiation. The less mature chondrocytes were seen at the base of the construct while hypertrophic chondrocytes and matrix mineralization was observed closer to the surface of the construct. The described differentiation protocol using hBMSCs in an agarose scaffold can be used to study the factors and conditions that influence the differentiation, proliferation, maturation, and zonal alignment of physeal chondrocytes. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1753–1759, 2012
Epidemiology and risk factors for perioperative mortality after total hip and knee arthroplasty
Authors: Memtsoudis Stavros G. , Pumberger Matthias , Ma Yan , Chiu Ya‐Lin , Fritsch Gerhard , Gerner Peter , Poultsides Lazaros , Valle Alejandro Gonzalez Della 
Published: April 2012

AbstractThe perioperative mortality of total knee and hip arthroplasties (TKA, THA) remains a major concern among health care providers and their patients. The increase in utilization of TKA and THA makes it imperative to be aware of factors that are associated with this unfortunate event. Therefore we analyzed the Nationwide Inpatient Sample data from 1998 to 2008 and compared admissions with perioperative mortality to those that survived their hospitalization. An estimated total of 4,438,213 TKA and 2,182,121 THA procedures were performed in the United States between 1998 and 2008. The average mortality rate for TKA was 0.13% and 0.18% for THA, or 0.34 and 0.44 events per 1,000 inpatient days, respectively. Independent risk factors for in‐hospital mortality were advanced age, male gender, ethnic minority background, emergency admission as well as a number of comorbidities and complications. Furthermore, we demonstrated that the timing of death occurred earlier after TKA when compared to THA, with 50% of fatalities occurring by day 4 versus day 6 of the hospitalization, respectively. This study provides nationally representative information on risk factors for and timing of perioperative mortality after TKA and THA. Our data can be used to assess the risk for perioperative mortality and to develop targeted intervention to decrease such risk. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1811–1821, 2012
Development of a Neolithic pine tree‐ring chronology for northern Scotland
Authors: Moir Andy 
Published: April 2012

AbstractThe peatlands of northern Scotland (one of the largest and most intact areas of blanket bog in the world) contain a rare widespread horizon of subfossil pine in stratigraphic context. Eighteen bog pine from three new sites are incorporated into a mean Neolithic pine chronology now composed of subfossil pine from 12 sites, which is tree‐ring‐dated against Irish bog pine chronologies to span 3198–2757 BC. Germination and peaks of radial growth infer drier conditions between 3199 and 3130 BC. Dying‐off phases and depression of growth reflect a change to wetter conditions between 3023 and 3002 BC and a terminal decline of pine between 2809 and 2782 BC. The close synchronization of germination/die‐off phases and major ring‐width variations between sites across this region indicates that the environmental changes are probably triggered by climate change. Twenty‐four bog pine samples remain unmatched. Future multi‐discipline research into this important example of climatic change at the Neolithic/Bronze Age transition is recommended. Copyright © 2012 John Wiley & Sons, Ltd.
SPECIAL semi‐LASER with lipid artifact compensation for 1H MRS at 7 T
Authors: Fuchs Alexander , Luttje Mariska , Boesiger Peter , Henning Anke 
Published: April 2012

AbstractThe measurement of full metabolic profiles at ultrahigh fields including low concentrated or fast‐relaxing metabolites is usually achieved by applying short echo time sequences. One sequence beside stimulated echo acquisition mode that was proposed in this regard is spin echo full intensity‐acquired localized spectroscopy. Typical problems that are still persistent for spin echo full intensity‐acquired localized spectroscopy are B1 inhomogeneities especially for signal acquisition with surface coils and chemical shift displacement artifacts due to limited B1 amplitudes when using volume coils. In addition, strong lipid contaminations in the final spectrum can occur when only a limited number of outer volume suppression pulses is used. Therefore, an adiabatic short echo time (= 19 ms) spin echo full intensity‐acquired localized spectroscopy semilocalization by adiabatic selective refocusing sequence is presented that is less sensitive to strong B1 variations and that offers increased excitation and refocusing pulse bandwidths than regular spin echo full intensity acquired localized spectroscopy. Furthermore, the existence of the systematic lipid artifact is identified and linked to unfavorable effects due to the preinversion localization pulse. A method to control this artifact is presented and validated in both phantom and in vivo measurements. The viability of the proposed sequence was further assessed for in vivo measurements by scanning 17 volunteers using a surface coil and moreover acquiring additional volume coil measurements. The results show well‐suppressed lipid artifacts, good signal‐to‐noise ratio, and reproducible fitting results in accordance with other published studies. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
Test–retest reproducibility of a rapid method to measure brain oxygen metabolism
Authors: Liu Peiying , Xu Feng , Lu Hanzhang 
Published: April 2012

AbstractCerebral metabolic rate of oxygen (CMRO2) is an important index of tissue viability and brain function, but this parameter cannot yet be measured routinely on clinical scanners. Recently, a noninvasive technique was proposed which estimates global CMRO2 by concomitantly measuring oxygen‐extraction‐fraction using T2‐relaxation‐under‐spin‐tagging MRI and pulse oximetry, and cerebral‐blood‐flow using phase‐contrast MRI. This study sought to establish a standard acquisition procedure for this technique and to evaluate its test–retest reproducibility in healthy subjects. Each subject was examined in five sessions and each session included two measurements. Intrasession, intersession, and intersubject coefficients of variation for CMRO2 were found to be 3.84 ± 1.44% (N = 7, mean ± standard deviation), 6.59 ± 1.56%, and 8.80% respectively. These reproducibility values were comparable or slightly superior to 15O positron emission tomography (PET) results reported in the literature. It was also found that oxygen‐extraction‐fraction and cerebral‐blood‐flow tended to co‐vary across sessions (P = 0.002) and subjects (P = 0.01), and their coefficients of variation were greater than that of CMRO2. The simplicity and reliability features may afford this global CMRO2 technique great potential for immediate clinical applications. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
‘To Suddenly Have a Name for this Thing… Was Wonderful’: The Patient's Experience of Receiving a Diagnosis of Systemic Lupus Erythematosus
Authors: Waldron Nicola , Brown Sue J. , Hewlett Sarah , Elliott Barbara , McHugh Neil , McCabe Candy S. 
Published: April 2012

AbstractObjectivesThe aim of this study was to explore the patient's perception of receiving a diagnosis of systemic lupus erythematosus (lupus) and reports on their experience of the period between onset of symptoms and receiving a definitive diagnosis.MethodsFocus groups were conducted in seven rheumatology centres. Forty‐three participants were purposively selected and data were subjected to thematic deductive analysis.ResultsFocus group data generated three major themes. ‘Diagnostic uncertainty and misdiagnosis’ describes the frustration for many of experiencing years of often debilitating symptoms that have gone unacknowledged by health professionals and misunderstood by themselves. Some experienced the trauma of being misdiagnosed, which impacted on how they adjusted to their final diagnosis of lupus. ‘Consequences of receiving a diagnosis’ highlights the feelings of relief for participants at finally having a diagnosis, despite its implications. However, the manner in which this knowledge was delivered was often inappropriate and unsupported, affecting how they adjusted to future management of their condition. ‘Impact on individuals' lives’ explores how many felt empowered by finally receiving recognition for their symptoms, but the diagnosis of a relatively unknown condition with often invisible symptoms impacted on the response and support they received from those around them.ConclusionIt is essential health professionals have a greater understanding of the patient experience prior to receiving a diagnosis of lupus. The individual experience from symptom onset to diagnosis has a direct impact on the patient's subsequent acceptance of their diagnosis and response to management and therefore justifies the need for further research in this field. Copyright © 2012 John Wiley & Sons, Ltd.
On enrichment functions in the extended finite element method
Authors: Zhu Qi‐Zhi 
Published: April 2012

SUMMARYThis paper presents mathematical derivation of enrichment functions in the extended finite element method for numerical modeling of strong and weak discontinuities. The proposed approach consists in combining the level set method with characteristic functions as well as domain decomposition and reproduction technique. We start with the simple case of a triangular linear element cut by one interface across which displacement field suffers a jump. The main steps towards the derivation of enrichment functions are as follows: (1) extension of the subfields separated by the interface to the whole element domain and definition of complementary nodal variables; (2) construction of characteristic functions for describing the geometry and physical field; (3) determination of the sets of basic nodal variables; (4) domain decompositions according to Step 3 and then reproduction of the physical field in terms of characteristic functions and nodal variables; and (5) comparison of the piecewise interpolations formulated at Steps 3 and 4 with the standard extended finite element method form, which yields enrichment functions. In this process, the physical meanings of both the basic and complementary nodal variables are clarified, which helps to impose Dirichlet boundary conditions. Enrichment functions for weak discontinuities are constructed from deeper insights into the structure of the functions for strong discontinuities. Relationships between the two classes of functions are naturally established. Improvements upon basic enrichment functions for weak discontinuities are performed so as to achieve satisfactory convergence and accuracy. From numerical viewpoints, a simple and efficient treatment on the issue of blending elements is also proposed with implementation details. For validation purposes, applications of the derived functions to heterogeneous problems with imperfect interfaces are presented. Copyright © 2012 John Wiley & Sons, Ltd.
Alginate grafted with poly(ε‐caprolactone): effect of enzymatic degradation on physicochemical properties
Authors: Benykhlef Samir , Dulong Virginie , Bengharez Zohra , Picton Luc , Guemra Kaddour , Le Cerf Didier 
Published: April 2012

AbstractThe paper discusses the enzymatic behaviour of a series of copolymers composed of alginate grafted with poly(ε‐caprolactone) (PCL) of various lengths and degrees of substitution. The study is focused on viscosity measurements and pyrene probe fluorescence with or without two enzymes: alginate lyase, which breaks the alginate backbone; and esterase, which breaks PCL pendent groups. Alginate lyase is inactive at pH = 3.8 and degrades quickly all copolymers at pH = 6.3. The degradation is not complete and is slowed down by the presence of PCL. Esterase degrades only copolymers with long pendent PCL groups. It has no effect on copolymers when PCL has a length of 530 g mol−1. These systems are good candidates for controlled release of drugs using an enzymatic method. Copyright © 2012 Society of Chemical Industry
Shifting focus from the population to the individual as a way forward in understanding, predicting and managing the complexities of evolution of resistance to pesticides
Authors: Renton Michael 
Published: April 2012

AbstractThe evolution of resistance to pesticides is often conceptualised and modelled at a population level, but population‐based approaches ignore important aspects of variability between individuals within populations that may be essential drivers of resistance. Here it is argued that individual‐based modelling has the potential to generate new insights and perspectives, thus deepening our understanding of the complexities of the evolutionary dynamics of resistance to pesticides. Copyright © 2012 Society of Chemical Industry
Formation Mechanism of LiFePO4 Sticks Grown by a Microwave‐Assisted Liquid‐Phase Process
Authors: Carriazo Daniel , Rossell Marta D. , Zeng Guobo , Bilecka Idalia , Erni Rolf , Niederberger Markus 
Published: April 2012

AbstractA time‐dependent study on the formation of LiFePO4 with olivine‐type structure is presented. The material is synthesized through a non‐aqueous route in benzyl alcohol assisted by microwave radiation. The LiFePO4 forms with an anisotropic morphology of microscale stick‐like particles. The detailed structure of these particles and their evolution with reaction time is revealed by transmission electron microscopy; a 3D reconstruction of a particle by electron tomography provides insight into the formation mechanism of these sticks. Without applying a thermal post‐annealing treatment or a carbon coating, the electrochemical behavior of the LiFePO4 microsticks is assessed for the preparation of cathodes in lithium‐ion batteries.
Mechanical Behavior of Deformation‐Induced α′‐Martensite and Flow Curve Modeling of a Cast CrMnNi TRIP‐Steel
Authors: Wolf Steffen , Martin Stefan , Krüger Lutz , Martin Ulrich , Lorenz Ulrike 
Published: April 2012

AbstractFor the modeling of the mechanical behavior of a two phase alloy with the rule of mixture (RM), the flow stress of both phases is needed. In order to obtain these information for the α′‐martensite in high alloyed TRIP‐steels, compression tests at cryogenic temperatures were performed to create a fully deformation‐induced martensitic microstructure. This martensitic material condition was subsequently tested under compressive loading at −60, 20, and 100°C and at strain rates of 10−3, 100, and 103 s−1 to determine the mechanical properties. The α′‐martensite possesses high strength and surprisingly good ductility up to 60% of compressive strain. Using the flow stress behavior of the α′‐martensite and that of the stable austenitic steel AISI 316L, the flow stress behavior of the high alloyed CrMnNi TRIP‐steel is modeled successfully using a special RM proposed by Narutani et al.
Simulation of Microsegregation in Multicomponent Alloys During Solidification
Authors: Salvino Ingrid M. , de‐Olivé Ferreira Leonardo , Ferreira Alexandre Furtado 
Published: April 2012

AbstractA phase‐field model is applied to the simulation of microsegregation and microstructure formation during the solidification of multicomponent alloys. The results of the one‐dimensional numerical simulations show good agreement with those from the Clyne–Kurz equation. Phase‐field simulations of non‐isothermal dendrite growth are examined. Two‐dimensional computation results exhibit different dendrites in multicomponent alloys for different solute concentrations. Changes in carbon concentration appear to affect dendrite morphology. This is due to a larger concentration and a lower equilibrium partition coefficient for carbon. On the other hand, changes in phosphorus concentration affect the dendrites and interface velocity in multicomponent alloys during solidification when phosphorus content is increased from 10−3 mol% P. With additional manganese, the solidification kinetics slow down; dendrite morphology, however, is not affected. The potential of the phase‐field model for applications pertaining to solidification has been demonstrated through the simulations herein.
Physicochemical, morphological, and thermal properties of starches separated from bulbs of four Chinese lily cultivars
Authors: Li Xia , Gao Wenyuan , Jiang Qianqian , Xia Yuzhuo 
Published: April 2012

AbstractThe starches separated from bulbs of four different lily cultivars (Lanzhou, Pinglu, Yixing‐1, and Yixing‐2) were investigated for physicochemical, morphological, crystalline, and thermal properties. AM content of lily bulbs starches from different cultivars ranged from 19.46 to 25.17%. The swelling power of starches ranged between 14.4 and 21.3 g/g, and the solubility ranged from 8.92 and 16.6% at the temperature of 85°C. Four cultivars of lily starches paste had excellent transparency and the transmittance value of Lanzhou lily as high as 54.7%. The transmittance of the gelatinized aqueous starch suspensions, from all lily cultivars, decreased with increase in storage period. The shape of starch granules varied from triangular to cylindrical and XRD of four lily starches all showed B‐type pattern. The transition temperatures and enthalpy of gelatinization (ΔHgel) were determined using DSC. Tp varied from 62.52 to 65.25°C. Pinglu lily starch showed the highest ΔHgel and gelatinization range (Tc–To) index among starches from four different lily cultivars.
Patterns in international bribery: Violations of the foreign corrupt practices act
Authors: Sanyal Rajib 
Published: April 2012

AbstractAn examination of U.S. Department of Justice prosecution of violations of the Foreign Corrupt Practices Act shows that officials in less developed countries are the likely recipients of bribes; that bribery occurs more often in the capital‐intensive industries of energy, construction, telecommunications, and military equipment; that firms more often tend to use intermediaries and agents to consummate illicit transactions rather than directly paying the intended beneficiary; and that the overall motivation for bribing is to secure a particular contract. This article reviews the evolving enforcement of the law and recommends a set of managerial actions to reduce corporate liability and improve governance practices. © 2012 Wiley Periodicals, Inc.
Political patronage and firm performance: Further evidence from Malaysia
Authors: Hassan Taufiq , Kabir Hassan M. , Mohamad Shamsher , Chaw Min Chen 
Published: April 2012

AbstractThis paper investigates the characteristics, performance, and share price reaction of politically connected firms versus a control sample of independent firms in Malaysia. Politically connected firms had higher level of leverage, lower profitability, and lower sales to profitability, and paid lower taxes and lower dividends compared to independent firms. Their share prices increase with the announcement of favorable political events. In terms of performance, the active rent‐seeking activities in return for preferential treatment produce comparable performance to independent firms during an economic upturn. However, their performance deteriorates more than independent firms during an economic downturn. The percentage of ownership of government institutions in politically connected firms is also much lower, and these firms use more Tier 1 auditors than the independent firms. Overall, the findings are consistent with expectations and evidence from similar studies in developed and developing economies. © 2012 Wiley Periodicals, Inc.