bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of background and surround on image color matching
Authors: Mandic Lidija , Grgic Sonja , Grgic Mislav 
Published: December 2007

AbstractIn this article, the corresponding‐color data for complex images reproduced on different media were obtained by simultaneous matching using an adjustment method. In our experiment printed color images and images displayed on a monitor were compared in different viewing conditions. The viewing condition varied in surround relative luminance and background. The experimental data show that surround relative luminance has little influence on color matching between printed and monitor images while changes in background modify color appearance. These results were used to evaluate different chromatic adaptation transforms (CAT). We found that for the same viewing conditions the SHARP transform shows the best agreement between the experimental and predicted data. SHARP transform can not predict accurately corresponding colors for blue and black regions. Therefore, we proposed new CAT that shows better characteristics than other transforms for cyan, green, and black colors and similar characteristics for other colors. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 244–251, 2007
A hybrid PET‐MRI: An integrated molecular‐genetic imaging system with HRRT‐PET and 7.0‐T MRI
Authors: Cho Zang‐Hee , Son Young‐Don , Kim Hang‐Keun , Kim Kyoung‐Nam , Oh Se‐Hong , Han Jae‐Yong , Hong In‐Ki , Kim Young‐Bo 
Published: December 2007

AbstractA PET‐MRI fusion system is developed for molecular‐genetic imaging. The purpose of the system is to obtain images of the in‐vivo human brain using two high‐end imaging devices, an advanced PET and an ultrahigh‐field MRI. These are the HRRT‐PET, a high‐resolution research tomograph dedicated to brain imaging on the molecular level, and the 7.0‐T MRI, an ultrahigh field version used for morphological imaging. HRRT‐PET delivers high‐resolution molecular imaging with a resolution down to 2.5 mm FWHM, which is currently the highest spatial resolution available for the observation of the human brain's molecular activities, including enzymes and receptors, which are manipulated genetically, such as reporter genes and probes. The 7.0‐T MRI began to reveal submillimeter resolution images of the cortical as well as deep brain areas, down to 250 μm, which allows us to visualize the fine details of the cortical and brainstem areas, including the line of Gennari in the visual cortex and the corticospinal tracts in the pontine area. The current PET‐MRI fusion imaging system produces the highest quality images of molecular and genetic activities of the human brain in vivo. It is starting to provide many answers to the key questions about the neurological diseases. Some of these start providing answers to many cognitive neuroscience problems with clear molecular and genetic bases. There is great potential in the PET‐MRI for early diagnosis of cancers as well as other neurological diseases, which we were previously unable to diagnose, such as microscopic molecular changes that occur in Parkinson's and Alzheimer's diseases. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 252–265, 2007
Effects of Nutrients, Fish, Charophytes and Algal Sediment Recruitment on the Phytoplankton Ecology of a Shallow Lake
Authors: Villena María‐José , Romo Susana 
Published: December 2007

AbstractThe influence of nutrient levels, fish density and charophytes on the phytoplankton ecology of a shallow Mediterranean lake was studied by means of an in situ mesocosm experiment. Different levels of nutrients and fish were added over the course of an eight‐week experiment, during which charophytes were removed towards the end. After submerged plants were removed, phytoplankton biomass increased significantly in all the mesocosms, with a reduction of algal diversity and species richness and dominance of cyanobacteria. Cyanobacteria recruited from the sediment played an important role in sustaining planktonic populations of the dominant species. Oscillatorial species (Pseudanabaena galeata, Planktolyngbya limnetica) dominated at higher nutrient levels (0.5–1 mg L–1 P and 5–10 mg L–1 N) and chroococcal cyanobacteria (Merismopedia tenuissima) at lower nutrient levels. Density of planktivorous fish had little effect on the algal recruitment from the sediment and phytoplankton biomass and diversity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leaf Decomposition and Stream Macroinvertebrate Colonisation of Japanese Knotweed, an Invasive Plant Species
Authors: Braatne Jeffrey H. , Sullivan S. Mažeika P. , Chamberlain Erin 
Published: December 2007

AbstractJapanese knotweed (Fallopia japonica Houtt. Ronse Decrane) is a highly invasive exotic plant that forms monocultures in riparian areas, effectively reducing plant diversity. This change in riparian plant composition alters the allocthonous input of leaf litter into adjacent streams. A field experiment was completed to understand how leaf decomposition and macroinvertebrate colonisation associated with the incorporation of exotic leaf litter. Leaf packs of Japanese knotweed, native alder (Alnus incana L.), native cottonwood (Populus trichocarpa Torr. and Gray), and two additional mixed pack types (alder and cottonwood; alder, cottonwood, and Japanese knotweed) were placed into a 50 m stream reach in Clear Creek, Idaho, and removed over a three‐month period. Leaf decomposition and macroinvertebrate assemblages were similar between leaf types, despite differences in nitrogen and phosphorus content. The diversity of leaf types within a given leaf pack also had no effect on leaf decomposition or macroinvertebrate dynamics. These findings suggest that allochthonous inputs of Japanese knotweed fulfill a detrital function similar to that of native leaf litter. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A DFT study of solvation effects on the tautomeric equilibrium and catalytic ylide generation of thiamin models
Authors: Alstrup Lie Mette , Schiøtt Birgit 
Published: December 2007

AbstractThiamin diphosphate (ThDP) is the biologically active form of vitamin B1 and an essential cofactor for a number of enzymes. The effect of solvent polarity on the tautomeric equilibria of ThDP using three model systems of the 4′‐aminopyrimidine ring is studied by density functional theory calculations (B3LYP/6‐311+G(d,p)//B3LYP/6‐31G(d)) in the gas phase and selected solvents (cyclohexane, ether, dichloroethane, and water). Solvation effects are investigated using three different schemes: implicit solvation by a continuum model, explicit solvation by inclusion of three water molecules mimicking the first solvation shell of the enzymatic environment, and by a mixed implicit/explicit solvation model. The 4′‐aminopyrimidine tautomer is more stable than the 1′,4′‐iminopyrimidine tautomer in all solvation schemes employed; however, the trend for the stabilities of the 1′,4′‐iminopyrimidine tautomer in the solvents depends on the specific ThDP‐model. Formation of the catalytic important ylide for ThDP‐dependent enzymes by deprotonation of ThDP(C2) is also investigated by localization of transition states for two possible pathways. Only the less stable tautomer, 1′,4′‐iminopyrimidine ThDP, is able to form the catalytic active ylide. Generation of the ylide through a direct intramolecular proton transfer from ThDP(C2) to the ThDP(N4′) nitrogen lone pair is favored by 6 kcal/mol in the gas phase, as compared to a water‐mediated ylide generation. However, inclusion of a dielectric medium reduces this difference dramatically. Furthermore, inclusion of two water molecules to model the apoenzymatic environment lowers the activation energies of both direct and water‐mediated ylide generation. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Simultaneous determination of antiepileptic drugs and their two active metabolites by HPLC
Authors: Budakova Lucie , Brozmanova Hana , Grundmann Milan , Fischer Jan 
Published: December 2007

AbstractAn HPLC procedure for the determination of lamotrigine (LAM) simultaneously with other antiepileptic drugs, primidone (PD), phenobarbital (PB), phenytoin (DPH), carbamazepine (CMZ), and two active metabolites 2‐phenyl‐2‐ethyl‐malonamide (PEMA) and 10,11‐dihydro‐10,11‐epoxycarbamazepine (EPO) was developed and validated. The method involves an ordinary RP system and a liquid–liquid extraction. The mobile phase consisting of water/ACN/methanol/triethylamine in the ratio 72 : 23 : 5 : 0.1 with pH 7.0 was selected as the best one after the assays testing both pH and triethylamine contents. UV detection was carried out at a wavelength of 220 nm and the whole analysis took 15 min. The method was linear in the range of 0.5–25 mg/L for PEMA and LAM; 1.25–25 mg/L for PD and CMZ; 0.625–12.5 mg/L for EPO; 1.5–60 mg/L for PB; and 1.25–50 mg/L for DPH, respectively. Within‐day CV% and between‐day CV% were within 10%. The developed HPLC method can be used for routine therapeutic drug monitoring both in children and adults.
Human papillomavirus, cervical carcinogenesis and chemoprevention with Indole derivates – a review of pathomechanisms
Authors: Rieck Gudrun C. , Fiander Alison N. 
Published: December 2007

AbstractCervical cancer is the second most common female cancer worldwide with high risk Human Papillomavirus (HPV) infection playing an essential aetiological role. Oestrogen interacts with HPV at a cellular level causing cell growth and inhibition of apoptosis. Indole derivatives, formed during digestion of cruciferous vegetables, have been shown to have chemopreventative properties inhibiting HPV transcription and influencing oestrogen metabolism. This review describes the interactions between HPV, oestrogen and indole derivatives. Further clinical research is required to evaluate the chemopreventative properties of these agents.
Evaluating the stress intensity factors of anisotropic bimaterials using boundary element method
Authors: Chen Chao‐Shi , Ke Chien‐Chung , Tu Chia‐Huei 
Published: December 2007

AbstractThis paper presents a boundary element method (BEM) procedure for a linear elastic fracture mechanics analysis in two‐dimensional anisotropic bimaterials. In this formulation, a displacement integral equation is only collocated on the uncracked boundary, and a traction integral equation is only collocated on one side of the crack surface. A fundamental solution (Green's function) for anisotropic bimaterials is also derived and implemented into the boundary integral formulation so that except for the interfacial crack part, the discretization along the interface can be avoided. A special crack‐tip element is introduced to capture the exact crack‐tip behavior. A computer program using FORTRAN has been developed to effectively calculate the stress intensity factors of an anisotropic bimaterial. This BEM program has been verified to have a good accuracy with previous studies. In addition, a central cracked bimaterial Brazilian specimen constituting cement and gypsum is prepared to conduct the Brazilian test under diametral loading. The result shows that the numerical analysis can predict relatively well the direction of crack initiation and the path of crack propagation. Copyright © 2007 John Wiley & Sons, Ltd.
Enhanced assumed strain (EAS) and assumed natural strain (ANS) methods for one‐point quadrature solid‐shell elements
Authors: Cardoso Rui P. R. , Yoon Jeong Whan , Mahardika M. , Choudhry S. , Alves de Sousa R. J. , Fontes Valente R. A. 
Published: December 2007

AbstractA reduced enhanced solid‐shell (RESS) finite element concept has been suggested recently by Alves de Sousa et al. (Int. J. Numer. Meth. Engng 2005; 62:952; Int. J. Numer. Meth. Engng 2006; 67:160; Int. J. Plasticity 2007; 23:490). Developments on the ‘RESS’ element were motivated by the following reasons: first, solid‐shell elements automatically incorporate the normal stress along the thickness direction, which makes them more suitable for the simulations with double‐sided contact than their shell counterparts; second, they have only translational degrees of freedom, which alleviates some difficulties associated with formulating complex shell formulations using nodal rotations; third, general constitutive models can be used and a reformulation for plane‐stress conditions is not necessary. Furthermore, traditionally, solid elements have been developed based on fully integrated schemes with limited number of integration points per single element layers which renders them computationally expensive. On the contrary, the solid‐shell element by Alves de Sousa et al. (Int. J. Numer. Meth. Engng 2005; 62:952; Int. J. Numer. Meth. Engng 2006; 67:160; Int. J. Plasticity 2007; 23:490) was developed for one single‐layer shell structure with reduced in‐plane and multiple integration points along the thickness direction of the shell. The formulation consists of several combinations of well‐known techniques to ameliorate locking problems as is the case of the enhanced assumed strain (EAS) method. However, the proposed ‘RESS’ solid shell did not consider the transverse shear components of hourglass (or physical stabilization) parts. This negligence produces a slightly flexible behavior of the element, but it can also cause the appearance of hourglass modes for several non‐linear applications including large rigid body rotations. Sometimes, the negligence brings a non‐positive‐definite status on the stiffness matrix. In order to overcome such drawbacks, a modified assumed natural strain (ANS) method considering the top and bottom surfaces of the element was incorporated for the transverse shear components. At the same time, new hourglass strains for the membrane field were constructed based on the stabilization vectors of Liu et al. (Comput. Meth. Appl. Mech. Engng 1998; 154:69). With these modifications, the improved element (called ‘M‐RESS’) passes both the membrane and bending patch tests and performs with remarkable stability and accuracy in sheet‐forming simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Study on sub‐cycling for flexible multi‐body dynamics based on Newmark method
Authors: Miao J. C. , Zhu P. , Shi G. L. , Chen G. L. 
Published: December 2007

AbstractA sub‐cycling algorithm presented by Belytschko and Mullen (Int. J. Numer. Meth. Engng 1978; 12(10):1575–1586) has been successfully applied in the finite element method. However, the problem of how to apply the sub‐cycling to flexible multi‐body dynamics (FMD) still lacks investigation. This paper presents a Newmark‐based sub‐cycling, which is suitable for solving condensed FMD models. Common‐step update formulae and sub‐step update formula for the sub‐cycling are established based on the original Newmark integration algorithm. Stability of the procedure is validated by means of energy balance checking during the integral process. Numerical examples indicate that the sub‐cycling is able to enhance the computational efficiency without dropping accuracy greatly. Copyright © 2007 John Wiley & Sons, Ltd.
An exploration of spousal separation and adaptation to long‐term disability: six elderly couples engaged in a horticultural programme
Authors: Martin Linda , Miranda Baldwin , BEAN Michelle 
Published: December 2007

AbstractThe main objective of the present study was to explore the impact of separation on couples where one spouse lives in a skilled nursing facility and the other spouse lives alone in the community. Six couples participated in a 10‐week gardening group. Semi‐structured interviews were conducted at the beginning of the study and observations were made and discussions engaged through the 10‐week horticultural programme. Thematic analysis of interviews and discussions revealed reduced social participation of community‐dwelling spouses in an effort to maintain their marital role. In one or more cases the non‐institutionalized spouse adapted to separation by developing social roles and relationships within the skilled nursing facility and continuing as a caregiver to their spouse. Occupational therapists are encouraged to include spouses in programmes to nurture healthy spousal roles. Further research is needed to explore how elderly couples may support each other through purposeful occupation while one spouse is in a long‐term care facility. Copyright © 2007 John Wiley & Sons, Ltd.
Towards self‐sterilizing medical devices: controlling infection
Authors: Madkour Ahmad E , Tew Gregory N 
Published: December 2007

AbstractMedical devices are an important component of modern medicine. In many cases, medical devices are used to improve the ‘quality of life’ for the patient, and their use is increasing dramatically. At the same time, the emergence of multi‐drug‐resistant bacteria, or ‘super‐bugs’, is a global crisis. At least in part, biomedical devices proliferate the growth of resistant bacteria. This has spurred new research aimed at the development of medical devices that prevent or control bacterial colonization, and this perspective discusses the current efforts in this area. Copyright © 2008 Society of Chemical Industry
Effect of oxidatively damaged DNA on the active site preorganization during nucleotide incorporation in a high fidelity polymerase from Bacillus stearothermophilus
Authors: Venkatramani Ravindra , Radhakrishnan Ravi 
Published: December 2007

AbstractWe study the effect of the oxidative lesion 8‐oxoguanine (8oxoG) on the preorganization of the active site for DNA replication in the closed (active) state of the Bacillus fragment (BF), a Klenow analog from Bacillus stearothermophilus. Our molecular dynamics and free energy simulations of explicitly solvated model ternary complexes of BF bound to correct dCTP/incorrect dATP opposite guanine (G) and 8oxoG bases in DNA suggest that the lesion introduces structural and energetic changes at the catalytic site to favor dATP insertion. Despite the formation of a stable Watson‐Crick pairing in the 8oxoG:dCTP system, the catalytic geometry is severely distorted to possibly slow down catalysis. Indeed, our calculated free energy landscapes associated with active site preorganization suggest additional barriers to assemble an efficient catalytic site, which need to be overcome during dCTP incorporation opposite 8oxoG relative to that opposite undamaged G. In contrast, the catalytic geometry for the Hoogsteen pairing in the 8oxoG:dATP system is highly organized and poised for efficient nucleotide incorporation via the “two‐metal‐ion” catalyzed phosphoryl transfer mechanism. However, the free energy calculations suggest that the catalytic geometry during dATP incorporation opposite 8oxoG is considerably less plastic than that during dCTP incorporation opposite G despite a very similar, well organized catalytic site for both systems. A correlation analysis of the dynamics trajectories suggests the presence of significant coupling between motions of the polymerase fingers and the primary distance for nucleophilic attack (i.e., between the terminal primer O3′ and the dNTP Pα. atoms) during correct dCTP incorporation opposite undamaged G. This coupling is shown to be disrupted during nucleotide incorporation by the polymerase with oxidatively damaged DNA/dNTP substrates. We also suggest that the lesion affects DNA interactions with key polymerase residues, thereby affecting the enzymes ability to discriminate against non‐complementary DNA/dNTP substrates. Taken together, our results provide a unified structural, energetic, and dynamic platform to rationalize experimentally observed relative nucleotide incorporation rates for correct dCTP/incorrect dATP insertion opposite an undamaged/oxidatively damaged template G by BF. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Statistical analysis of donation–transfusion data with complex correlation
Authors: Reilly Marie , Szulkin Robert 
Published: December 2007

AbstractBlood‐borne transmission of disease is estimated from linked data records from blood donors and transfusion recipients. However, such data are characterized by complex correlation due to donors typically contributing many donations and recipients being transfused with multiple units of blood product. In this paper, we present a method for analysing such data, by using a modification of a nested case–control design. For recipients who develop the disease of interest (cases) and their matched controls, all donors who contributed blood to these individuals define clusters or ‘families’ of related individuals. Using a Cox regression model for the hazard of the individuals within clusters of donors, we estimate the risk of transmission, and a bootstrap step provides valid standard errors provided the clusters are independent. As an illustration, we apply the method to the analysis of a large database of Swedish donor and recipient records linked to the population cancer register. We investigate whether there is an increased risk of cancer in recipients transfused with blood from donors who develop cancer after donating. Our method provides a powerful alternative to the small ‘look‐back’ studies typical of transfusion medicine and can make an important contribution to haemovigilance efforts. Copyright © 2007 John Wiley & Sons, Ltd.
Selection of important variables and determination of functional form for continuous predictors in multivariable model building
Authors: Sauerbrei Willi , Royston Patrick , Binder Harald 
Published: December 2007

AbstractIn developing regression models, data analysts are often faced with many predictor variables that may influence an outcome variable. After more than half a century of research, the ‘best’ way of selecting a multivariable model is still unresolved. It is generally agreed that subject matter knowledge, when available, should guide model building. However, such knowledge is often limited, and data‐dependent model building is required. We limit the scope of the modelling exercise to selecting important predictors and choosing interpretable and transportable functions for continuous predictors. Assuming linear functions, stepwise selection and all‐subset strategies are discussed; the key tuning parameters are the nominalP‐value for testing a variable for inclusion and the penalty for model complexity, respectively. We argue that stepwise procedures perform better than a literature‐based assessment would suggest.Concerning selection of functional form for continuous predictors, the principal competitors are fractional polynomial functions and various types of spline techniques. We note that a rigorous selection strategy known as multivariable fractional polynomials (MFP) has been developed. No spline‐based procedure for simultaneously selecting variables and functional forms has found wide acceptance. Results of FP and spline modelling are compared in two data sets. It is shown that spline modelling, while extremely flexible, can generate fitted curves with uninterpretable ‘wiggles’, particularly when automatic methods for choosing the smoothness are employed. We give general recommendations to practitioners for carrying out variable and function selection. While acknowledging that further research is needed, we argue why MFP is our preferred approach for multivariable model building with continuous covariates. Copyright © 2007 John Wiley & Sons, Ltd.