bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rejection of trace organic pollutants with high pressure membranes (NF/RO)
Authors: Verliefde A.R.D. , Heijman S.G.J. , Cornelissen E.R. , Amy G.L. , Van der Bruggen B. , van Dijk J.C. 
Published: May 2008

AbstractThis article presents a modeling approach for the rejection of trace organic pollutants in high‐pressure membranes. The rejection values of uncharged organic solutes with a wide range of solute size and hydrophobicity are determined. Sigmoidal rejection curves are constructed and modeled for solutes of different hydrophobicity. The model is based on a log‐normal pore size distribution model. A model is also presented to model the rejection of charged organic solutes, based on the rejection of uncharged solutes and the concept of a “charge concentration polarization.” Moreover, scale‐up issues arising when translating results from bench‐scale units to full‐scale plants are addressed, by assessing the viability of a full‐scale rejection model. The full‐scale model is based on a convection‐diffusion model for the transport of organic solutes through the high‐pressure membranes and the use of mass balances in the system. © 2008 American Institute of Chemical Engineers Environ Prog, 2008
A prevalence‐based association test for case‐control studies
Authors: Ryckman Kelli K. , Jiang Lan , Li Chun , Bartlett Jacquelaine , Haines Jonathan L. , Williams Scott M. 
Published: May 2008

AbstractGenetic association is often determined in case‐control studies by the differential distribution of alleles or genotypes. Recent work has demonstrated that association can also be assessed by deviations from the expected distributions of alleles or genotypes. Specifically, multiple methods motivated by the principles of Hardy‐Weinberg equilibrium (HWE) have been developed. However, these methods do not take into account many of the assumptions of HWE. Therefore, we have developed a prevalence‐based association test (PRAT) as an alternative method for detecting association in case‐control studies. This method, also motivated by the principles of HWE, uses an estimated population allele frequency to generate expected genotype frequencies instead of using the case and control frequencies separately. Our method often has greater power, under a wide variety of genetic models, to detect association than genotypic, allelic or Cochran‐Armitage trend association tests. Therefore, we propose PRAT as a powerful alternative method of testing for association. Genet. Epidemiol. 2008. © 2008 Wiley‐Liss, Inc.
Mapping the signal‐to‐noise‐ratios of cortical sources in magnetoencephalography and electroencephalography
Authors: Goldenholz Daniel M. , Ahlfors Seppo P. , Hämäläinen Matti S. , Sharon Dahlia , Ishitobi Mamiko , Vaina Lucia M. , Stufflebeam Steven M. 
Published: May 2008

AbstractAlthough magnetoencephalography (MEG) and electroencephalography (EEG) have been available for decades, their relative merits are still debated. We examined regional differences in signal‐to‐noise‐ratios (SNRs) of cortical sources in MEG and EEG. Data from four subjects were used to simulate focal and extended sources located on the cortical surface reconstructed from high‐resolution magnetic resonance images. The SNR maps for MEG and EEG were found to be complementary. The SNR of deep sources was larger in EEG than in MEG, whereas the opposite was typically the case for superficial sources. Overall, the SNR maps were more uniform for EEG than for MEG. When using a noise model based on uniformly distributed random sources on the cortex, the SNR in MEG was found to be underestimated, compared with the maps obtained with noise estimated from actual recorded MEG and EEG data. With extended sources, the total area of cortex in which the SNR was higher in EEG than in MEG was larger than with focal sources. Clinically, SNR maps in a patient explained differential sensitivity of MEG and EEG in detecting epileptic activity. Our results emphasize the benefits of recording MEG and EEG simultaneously. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
Effects of aging on cerebral blood flow, oxygen metabolism, and blood oxygenation level dependent responses to visual stimulation
Authors: Ances Beau M. , Liang Christine L. , Leontiev Oleg , Perthen Joanna E. , Fleisher Adam S. , Lansing Amy E. , Buxton Richard B. 
Published: May 2008

AbstractCalibrated functional magnetic resonance imaging (fMRI) provides a noninvasive technique to assess functional metabolic changes associated with normal aging. We simultaneously measured both the magnitude of the blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) responses in the visual cortex for separate conditions of mild hypercapnia (5% CO2) and a simple checkerboard stimulus in healthy younger (n = 10, mean: 28‐years‐old) and older (n = 10, mean: 53‐years‐old) adults. From these data we derived baseline CBF, the BOLD scaling parameter M, the fractional change in the cerebral metabolic rate of oxygen consumption (CMRO2) with activation, and the coupling ratio n of the fractional changes in CBF and CMRO2. For the functional activation paradigm, the magnitude of the BOLD response was significantly lower for the older group (0.57 ± 0.07%) compared to the younger group (0.95 ± 0.14%), despite the finding that the fractional CBF and CMRO2 changes were similar for both groups. The weaker BOLD response for the older group was due to a reduction in the parameter M, which was significantly lower for older (4.6 ± 0.4%) than younger subjects (6.5 ± 0.8%), most likely reflecting a reduction in baseline CBF for older (41.7 ± 4.8 mL/100 mL/min) compared to younger (59.6 ± 9.1 mL/100 mL/min) subjects. In addition to these primary responses, for both groups the BOLD response exhibited a post‐stimulus undershoot with no significant difference in this magnitude. However, the post‐undershoot period of the CBF response was significantly greater for older compared to younger subjects. We conclude that when comparing two populations, the BOLD response can provide misleading reflections of underlying physiological changes. A calibrated approach provides a more quantitative reflection of underlying metabolic changes than the BOLD response alone. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
White matter hyperintensities in the forties: Their prevalence and topography in an epidemiological sample aged 44–48
Authors: Wen Wei , Sachdev Perminder S. , Li Jason J. , Chen Xiaohua , Anstey Kaarin J. 
Published: May 2008

AbstractWhite matter hyperintensities (WMHs) are a frequent finding on T2‐weighted MRI of the brain in elderly individuals, but their prevalence and severity in younger asymptomatic populations is less well studied. We report the topography of WMHs on T2‐weighted fluid inversion recovery (FLAIR) MRI in 428 individuals aged 44‐48 years recruited randomly from a healthy community sample. WMHs were delineated from FLAIR and T1‐weighted scans by using a computer algorithm, further verified and then classified using k‐nearest neighbor (kNN) algorithm into deep WMH (DWMH), and periventricular WMH (PVWMH), which included extended periventricular “rims” and frontal and occipital “caps”. Small caps and pencil‐thin rims were not taken as WMHs for this analysis. The new computer algorithm was validated and compared with the scores of visual rating, and the correspondence between the two methods was high. We found that 218 (50.9%) subjects had WMHs. 146 of the 218 (34.1% of whole sample population of 428) subjects had deep white matter hyperintensities (DWMHs). The average number of WMH clusters (occurrences) per brain was 1.37 (0.94 for DWMH and 0.43 for pathological PVWMH) and the mean WMH tissue volume was 0.278 ml. There was no significant sex difference in the severity and distribution of WMHs. The study suggests that small punctate or focal WMHs are common in the brains of individuals in their 40s, and may represent an early stage of development of these lesions. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
A voxel‐based morphometry study of frontal gray matter correlates of impulsivity
Authors: Matsuo Koji , Nicoletti Mark , Nemoto Kiyotaka , Hatch John P. , Peluso Marco A.M. , Nery Fabiano G. , Soares Jair C. 
Published: May 2008

AbstractImpulsivity is a personality trait exhibited by healthy individuals, but excessive impulsivity is associated with some mental disorders. Lesion and functional neuroimaging studies indicate that the ventromedial prefrontal region (VMPFC), including the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC) and medial prefrontal cortex, and the amygdala may modulate impulsivity and aggression. However, no morphometric study has examined the association between VMPFC and impulsivity. We hypothesized that healthy subjects with high impulsivity would have smaller volumes in these brain regions compared with those with low impulsivity. Sixty‐two healthy subjects were studied (age 35.4 ± 12.1 years) using a 1.5‐T MRI system. The Barratt impulsiveness scale (BIS) was used to assess impulsivity. Images were processed using an optimized voxel‐based morphometry (VBM) protocol. We calculated the correlations between BIS scale scores and the gray matter (GM) and white matter (WM) volumes of VMPFC and amygdala. GM volumes of the left and right OFC were inversely correlated with the BIS total score (P = 0.04 and 0.02, respectively). Left ACC GM volumes had a tendency to be inversely correlated with the BIS total score (P = 0.05). Right OFC GM volumes were inversely correlated with BIS nonplanning impulsivity, and left OFC GM volumes were inversely correlated with motor impulsivity. There were no significant WM volume correlations with impulsivity. The results of this morphometry study indicate that small OFC volume relate to high impulsivity and extend the prior finding that the VMPFC is involved in the circuit modulating impulsivity. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
Endogenous brain oscillations and related networks detected by surface EEG‐combined fMRI
Authors: Laufs Helmut 
Published: May 2008

AbstractIt is difficult to study the brain “at rest” with an approach generally pursued in science when external manipulation (independent variable) is used to obtain informative measurements (dependent variable) about the object of interest. External manipulation in its classic sense may suspend the resting state, and hence the object of interest will evade. Naturally, unless in a final and irreversible state, biological rest will always be an endogenously dynamic process. Combining two modalities, electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), to simultaneously measure the brain's activity from two angles, one can be chosen to be interpreted as the independent variable and the other as the dependent variable, and without external manipulation the brain's spontaneous dynamics can be studied. The EEG, for example, observes endogenous modulations of vigilance and detects spontaneous events such as sleep spindles or epileptic discharges and can be used as the independent variable, i.e., to form a regressor to interrogate the fMRI data (dependent variable). The opposite is possible as well, and data fusion attempts try using all data both as dependent and independent variables at the same time. This review limits itself to an exemplary discussion of simultaneous EEG/fMRI studies in humans, and among a variety of proposed resting state networks only discusses a few, especially those for which non‐resting state literature has proposed a functional meaning: the “default mode” network and an attentional network. It will be shown that one EEG feature can correlate with different fMRI activation maps and that a single resting state network may be associated with a variety of EEG patterns giving insight into the function of different resting states and the relationship between the two modalities in themselves. Hum Brain Mapp 2008. © 2008 Wiley‐Liss, Inc.
Consciousness and cerebral baseline activity fluctuations
Authors: Boly Melanie , Phillips Christophe , Balteau Evelyne , Schnakers Caroline , Degueldre Christian , Moonen Gustave , Luxen Andre , Peigneux Philippe , Faymonville Marie‐Elisabeth , Maquet Pierre , Laureys Steven 
Published: May 2008

AbstractThe origin of within‐subject variability in perceptual experiments is poorly understood. We here review evidence that baseline brain activity in the areas involved in sensory perception predict subsequent variations in sensory awareness. We place these findings in light of recent findings on the architecture of spontaneous BOLD fluctuations in the awake human brain, and discuss the possible origins of the observed baseline brain activity fluctuations. Hum Brain Mapp 2008. © 2008 Wiley‐Liss, Inc.
Adversities of acculturation? Prevalence of obesity among immigrants
Authors: Kaushal Neeraj 
Published: May 2008

AbstractI study factors associated with prevalence of obesity among immigrants as the length of their stay in the US becomes longer. Using the National Health Interview Surveys for 1990–2004, I create ‘synthetic cohorts’ of immigrants that allow controlling for two important determinants of obesity: age at arrival and period of arrival in the US. I find that immigrants with a BA degree did not experience any change in obesity as their stay in the US advanced. Obesity among those without a BA degree, however, increased with duration of stay. Similarly, while some ethnic groups experienced increase in obesity with duration, others did not. For those who experienced increase in obesity with duration, the rise was higher during the first five years of residence than later and greater for those who arrived at a relatively young age. Copyright © 2008 John Wiley & Sons, Ltd.
Evaluation of three evaporation estimation methods in a Canadian prairie landscape
Authors: Armstrong Robert N. , Pomeroy John W. , Martz Lawrence W. 
Published: May 2008

AbstractThree approaches to estimating actual evaporation (evaporation from water, soil, and transpiration from plants) are evaluated against eddy covariance observations taken during the summer period of 2006 over an upland mixed‐grass site in the St Denis National Wildlife Area, central Saskatchewan. The Penman–Monteith (P–M) combination approach explicitly takes into consideration the influence of surface resistance and available energy in order to calculate evaporation from non‐saturated surfaces. The Granger and Gray (G–D) expression is an extension of the Penman equation to the case of non‐saturated surfaces using a complimentary approach that considers the relative evaporation G, or the ratio of actual to potential evaporation as an inverse function of the relative drying power of the air, D. D is a function of the humidity deficit and available energy. The Dalton‐type bulk transfer (BT) approach typically applied in land surface schemes considers turbulent transfer along the humidity gradient between the surface and atmosphere as diagnosed from the land surface temperature. In this case, surface temperature was observed radiometrically rather than modelled. The models were evaluated for several temporal scales from 15 min to seasonal, and compared with measured evaporation data obtained by an eddy covariance system. Results suggest that all three approaches have ‘reasonable’ applicability for estimating evaporation at point‐scales for periods longer than daily, but none of the methods provide consistently reliable daily or sub‐daily estimates of evaporation. Copyright © 2008 John Wiley & Sons, Ltd.
Haplotype‐specific expression of the human PDGFRA gene correlates with the risk of glioblastomas
Authors: Toepoel Mascha , Joosten Paul H.L.J. , Knobbe Christiane B. , Afink Gijs B. , Zotz Rainer B. , Steegers‐Theunissen Regine P.M. , Reifenberger Guido , van Zoelen Everardus J.J. 
Published: May 2008

AbstractAberrant expression of the platelet‐derived growth factor α‐receptor (PDGFRA) gene has been associated with various diseases, including neural tube defects and gliomas. We have previously identified 5 distinct haplotypes for the PDGFRA promoter region, designated H1, H2α, H2β, H2γ and H2δ. Of these haplotypes H1 and H2α are the most common, whereby H1 drives low and H2α high transcriptional activity in transient transfection assays. Here we have investigated the role of these PDGFRA promoter haplotypes in gliomagenesis at both the genetic and cellular level. In a case–control study on 71 glioblastoma patients, we observed a clear underrepresentation of H1 alleles, with pH1 = 0.141 in patients and pH1 = 0.211 in a combined Western European control group (n = 998, p < 0.05). Furthermore, in 3 out of 4 available H1/H2α heterozygous human glioblastoma cell lines, H1‐derived mRNA levels were more than 10‐fold lower than from H2α, resulting at least in part from haplotype‐specific epigenetic differences such as DNA methylation and histone acetylation. Together, these results indicate that PDGFRA promoter haplotypes may predispose to gliomas. We propose a model in which PDGFRA is upregulated in a haplotype‐specific manner during neural stem cell differentiation, which affects the pool size of cells that can later undergo gliomagenesis. © 2008 Wiley‐Liss, Inc.
Low CAIX expression and absence of VHL gene mutation are associated with tumor aggressiveness and poor survival of clear cell renal cell carcinoma
Authors: Patard Jean‐Jacques , Fergelot Patricia , Karakiewicz Pierre I. , Klatte Tobias , Trinh Quoc‐Dien , Rioux‐Leclercq Nathalie , Said Jonathan W. , Belldegrun Arie S. , Pantuck Allan J. 
Published: May 2008

AbstractWe attempted to describe, in a series of clear cell renal cell carcinoma (RCC), the relationship between CAIX expression, VHL gene mutations, tumor characteristics and outcome. Radical nephrectomy was performed in 100 patients. Genomic DNA was extracted from frozen tumor samples. Four amplimers covering the whole coding sequence of the VHL gene were synthesized by PCR and sequenced. The monoclonal antibody M75 was used to evaluate CAIX protein expression immunohistochemically. VHL mutations were identified in 58 patients (58%) and high CAIX expression (>85%) was observed in 78 (78%). Tumors with VHL mutation showed higher CAIX expression than those without (p = 0.02). Low CAIX expression and absence of VHL mutation were associated with a more advanced tumors e.g., higher T stages and presence of metastases. VHL mutation and high CAIX expression predicted longer progression‐free survival (p = 0.037) and disease‐specific survival (p = 0.001), respectively. In combination, they defined three prognostic groups (p = 0.002): (i) good prognosis, defined as VHL mutation and high CAIX (2‐year survival: 86%), (ii) intermediate prognosis with either VHL mutation or high CAIX (69%), and (iii) poor prognosis with no VHL mutation and low CAIX (45%, median survival 18 months). CAIX expression, but not VHL mutational status, was an independent prognostic factor in multivariate analysis. Taken together, CAIX expression and VHL mutational status are able to stratify patients with clear cell RCC into distinct groups with regards to clinicopathological variables and prognosis, with low CAIX expression and absence of VHL mutation being associated with a poor clinicopathological phenotype and diminished survival. © 2008 Wiley‐Liss, Inc.
Electron crystallography of aquaporins
Authors: Andrews Simeon , Reichow Steve L. , Gonen Tamir 
Published: May 2008

AbstractAquaporins are a family of ubiquitous membrane proteins that form a pore for the permeation of water. Both electron and X‐ray crystallography played major roles in determining the atomic structures of a number of aquaporins. This review focuses on electron crystallography, and its contribution to the field of aquaporin biology. We briefly discuss electron crystallography and the two‐dimensional crystallization process. We describe features of aquaporins common to both electron and X‐ray crystallographic structures; as well as some structural insights unique to electron crystallography, including aquaporin junction formation and lipid‐protein interactions. © 2008 IUBMB IUBMB Life, 60(7): 430–436, 2008
Molecular mechanisms of oxidative stress‐induced carcinogenesis: From epidemiology to oxygenomics
Authors: Toyokuni Shinya 
Published: May 2008

AbstractOxidative stress is associated with inflammation, radiation, reperfusion, and iron overload. Epidemiological observations have shown that oxidative stress is one of the major sources of carcinogenesis, the top‐ranked cause of human mortality worldwide. In situations of oxidative stress, reactive oxygen and nitrogen species contribute to the alteration of genome information, presumably followed by selection of the adapted proliferating cells in a given environment. Recent data suggest that common molecular mechanisms exist in oxidative stress‐induced carcinogenesis, including p16INK4A inactivation. Thus far, oxidative DNA damage in the genome as a cause of mutation has been recognized to be randomly distributed based on in vitro experiments, while localization of oxidative DNA damage in vivo has not been pursued. However, using a novel technique based on DNA immunoprecipitation in combination with genome information, we now know that the localization of oxidative DNA damage is not random in vivo. We propose to call this rather novel research area “oxygenomics.” Many signaling pathways start from the recognition of DNA damage. Thus, possible underlying principles should be elucidated in association with each cell type, the genomic location of the damage with its transcriptional activity as well as the chromatin status determining the epigenetic effect. © 2008 IUBMB IUBMB Life, 60(7): 441–447, 2008
Chemically modified light‐curable chitosans with enhanced potential for bone tissue repair
Authors: Qiu Yongzhi , Zhang Ning , Kang Qian , An Yuehuei , Wen Xuejun 
Published: May 2008

AbstractLight curable polymers are showing great potential in overcoming some of the current obstacles in bone repair. With stereolithography, they can be fabricated into scaffolds with desired topography for repairing bone defects in irregular shapes. In this study, we developed a series of light curable chitosans, which have photocurability and good solubility in organic solvent. Through adjusting the feeding ratio of the raw components, the content of photocurable groups in the backbone of chitosan can be controlled. The light curable chitosans were characterized through FTIR–ATR and 1H NMR, which also confirmed their controllable photocurability. NIH 3T3 fibroblasts were co‐cultured with the photocured samples for 7 days and the results indicated that these photocured chitosans are cyto‐compatible. Scaffolds with interconnected pores, fabricated using salt leaching and photocuring and seeded with fetal bovine osteoblasts, were implanted subcutaneously in the backs of athymic rat. Histological study on the implants at 6 weeks showed that the photocured chitosans have good osteoconductivity. The results indicated the light curable chitosans have good biocompatibility and osteoconductivity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009