bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of nickel(II) ions on the growth and bioaccumulation properties of Escherichia coli
Authors: Wu Laiyan , Yu Junxia , Sun Xiaomei , Li Buhai 
Published: November 2008

AbstractThe influence of nickel(II) ions concentration on the growth and nickel(II) bioaccumulation properties of Escherichia coli (cultivated in the LB medium) was studied. When the investigated initial concentration of nickel(II) was in the range of 20–300 mg L−1, it was found that the growth of E. coli was delayed obviously with the increasing nickel(II) ion concentration, while the accumulation capacity increased until the maximum was obtained. FTIR spectrum showed that the peak near 3300 cm−1 shifted remarkably, and simultaneously, the peaks at 1660 cm−1 strengthened according to the nickel(II) concentration. As shown by the X‐ray photoelectron spectroscopy analysis, the nitrogen, sulphur, and phosphorus contents of the cultivated cell were reduced, while the content of oxygen was increased. The biologic characteristics of the microorganism did not change as shown in the transmission electron microscope images. © 2008 American Institute of Chemical Engineers Environ Prog, 2009
Tick sizes and relative rates of price discovery in stock, futures, and options markets: Evidence from the Taiwan stock exchange
Authors: Chen Yu‐Lun , Gau Yin‐Feng 
Published: November 2008

AbstractThis study examines the competition in price discovery among stock index, index futures, and index options in Taiwan. The price‐discovery ability of the Taiwan Top 50 Tracker Fund, an exchange‐traded fund based on the Taiwan 50 index is examined. The authors find that, after the minimum tick size in the stock market decreases, the bid–ask spreads of the component stocks of the stock index and the Taiwan Top 50 Tracker Fund get lower, and the contribution of the spot market to price discovery increases. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 29:74–93, 2009
Modifications to the Patient Rule‐Induction Method that utilize non‐additive combinations of genetic and environmental effects to define partitions that predict ischemic heart disease
Authors: Dyson Greg , Frikke‐Schmidt Ruth , Nordestgaard Børge G. , Tybjærg‐Hansen Anne , Sing Charles F. 
Published: November 2008

AbstractThis article extends the Patient Rule‐Induction Method (PRIM) for modeling cumulative incidence of disease developed by Dyson et al. (Genet Epidemiol 31:515–527) to include the simultaneous consideration of non‐additive combinations of predictor variables, a significance test of each combination, an adjustment for multiple testing and a confidence interval for the estimate of the cumulative incidence of disease in each partition. We employ the partitioning algorithm component of the Combinatorial Partitioning Method to construct combinations of predictors, permutation testing to assess the significance of each combination, theoretical arguments for incorporating a multiple testing adjustment and bootstrap resampling to produce the confidence intervals. An illustration of this revised PRIM utilizing a sample of 2,258 European male participants from the Copenhagen City Heart Study is presented that assesses the utility of genetic variants in predicting the presence of ischemic heart disease beyond the established risk factors. Genet. Epidemiol. 2009. © 2008 Wiley‐Liss, Inc.
The prevention of dementia
Authors: Peters Ruth 
Published: November 2008

AbstractObjectiveDementia is prevalent in older adults and the population is ageing. Many factors have been associated with dementia and anything that may aid the prevention of dementia is of importance.MethodThe literature in this area was evaluated and information relating to the various factors that may impact upon the prevention of dementia is presented below.ResultsFactors that have been associated with a possible increased risk of developing dementia include high blood pressure, (at least in midlife), high body mass index, smoking and possibly diabetes although the evidence is mixed. There is currently no clear evidence with regard to cholesterol and metabolic syndrome although both may be implicated. Having education and maintaining a Mediterranean diet, including vegetable, fruit and fish intake, have been linked to a lower incidence of dementia as has low to moderate alcohol intake. Although care must be taken with the latter given the different characteristics of the studies reporting on alcohol and dementia.ConclusionIt may be that risk and protective factors vary with age, however, in the absence of prophylactic treatment it seems likely that the maintenance of a healthy lifestyle may represent the best option with regard to the prevention of dementia. Copyright © 2008 John Wiley & Sons, Ltd.
Selective neck dissection following adjuvant therapy for advanced head and neck cancer
Authors: Mukhija Vijay , Gupta Sachin , Jacobson Adam S. , Anderson Eloy Jean , Genden Eric M. 
Published: November 2008

AbstractBackground.In the past, surgeons believed that in order to eradicate regional disease, a radical or modified radical neck dissection was necessary. An evolution in surgical principles and the popularization of primary chemoradiation has raised the questions regarding the role of neck dissection and the extent of neck dissection following therapy. The aim of this study was to determine the efficacy of selective neck dissection (SND) for patients with N2 or N3 disease following treatment with primary radiation therapy or chemoradiation.Methods.A retrospective review of 58 patients with stage III or IV head and neck squamous cell carcinoma was conducted. The primary sites included base of tongue (n = 15), hypopharynx (n = 12), tonsil (n = 16), larynx (n = 11), and unknown primary (n = 4). Definitive treatment consisted of either concomitant chemoradiation (67.2%) or external beam radiation therapy (32.8%). In the monotherapy group, all patients received a total curative dose of 66 to 72 Gy in once‐daily fractions of 180 to 200 cGy. The combined chemoradiation group received a similar radiation schedule and a 4‐day continuous infusion of cisplatin (20 mg/m2/day) and 5‐fluorouracil (1000 mg/m2/day). A planned SND of levels II to IV was performed on all the patients 3 to 6 weeks after completion of definitive medical therapy.Results.Seventy neck dissections were performed on 58 patients with advanced neck disease following radiation or chemoradiation. The median time of follow‐up was 34 months (range, 9–71 months) following the neck dissection. Pathologically, 22.4% (13/58) of the patients had viable tumor cells identified in the neck dissection specimen. Seventy‐two percent of the patients are currently alive, and 28% died as a result of distant disease, local or regional recurrence, or other causes. Of patients who died from distant disease, 11% had pathological evidence of residual tumor cells identified in the neck dissection specimen. Of patients who died from local or regional disease, 50% had pathological evidence of residual tumor cells identified in the neck dissection specimen.Conclusion.The rate of regional recurrence following SND is similar to reported rates following modified/radical neck dissection. This suggests that SND provides an appropriate surgical option for advanced neck disease in select patients following adjuvant therapy. © 2008 Wiley Periodicals, Inc. Head Neck, 2009.
CD133+ liver cancer stem cells from methionine adenosyl transferase 1A–deficient mice demonstrate resistance to transforming growth factor (TGF)-β–induced apoptosis #
Authors: Ding Wei , Mouzaki Marialena , You Hanning , Laird Joshua C. , Mato Jose , Lu Shelly C. , Rountree Bart C. 
Published: November 2008

Abstract
Methionine adenosyltransferase (MAT) is an essential enzyme required for S-adenosylmethionine biosynthesis. Hepatic MAT activity falls during chronic liver injury, and mice lacking Mat1a develop spontaneous hepatocellular carcinoma by 18 months. We have previously demonstrated that CD133+CD45− oval cells isolated from 16-month-old Mat1a
−/− mice represent a liver cancer stem cell population. The transforming growth factor β (TGF-β) pathway constitutes a central signaling network in proliferation, apoptosis, and tumorigenesis. In this study, we tested the response of tumorigenic liver stem cells to TGF-β. CD133+CD45− oval cells were isolated from premalignant 16-month-old Mat1a
−/− mice by flow cytometry and expanded as five clone lines derived from a single cell. All clone lines demonstrated expression of both hepatocyte and cholangiocyte markers and maintained a small population (0.5% to 2%) of CD133+ cells in vitro, and three of five clone lines produced tumors. Although TGF-β1 inhibited cell growth equally in CD133− and CD133+ cells from each clone line, the CD133+ population demonstrated significant resistance to TGF-β–induced apoptosis compared with CD133− cells. Furthermore, CD133+ cells demonstrated a substantial increase in mitogen-activated protein kinase (MAPK) pathway activation, as demonstrated by phosphorylated extracellular signal-regulated kinase levels before and after TGF-β stimulation. MAPK inhibition using mitogen-activated protein kinase kinase 1 (MEK1) inhibitor PD98059 led to a significant increase in TGF-β–induced apoptosis in CD133+ cells. Conversely, a constitutively active form of MEK1 blocked the apoptotic effects of TGF-β in CD133− cells. Conclusion: CD133+ liver cancer stem cells exhibit relative resistance to TGF-β–induced apoptosis. One mechanism of resistance to TGF-β–induced apoptosis in CD133+ cancer stem cells is an activated mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. (Hepatology 2009.)
Factors of accuracy of transient elastography (fibroscan) for the diagnosis of liver fibrosis in chronic hepatitis C #
Authors: Lucidarme Damien , Foucher Juliette , Le Bail Brigitte , Vergniol Julien , Castera Laurent , Duburque Clotilde , Forzy Gérard , Filoche Bernard , Couzigou Patrice , de Lédinghen Victor 
Published: November 2008

Abstract
The purpose of this study was to assess the influence of success rate and interquartile range on the accuracy of transient elastography for the diagnostic of fibrosis in hepatitis C virus infection. Two-hundred fifty-four consecutive patients had liver stiffness measurements and liver biopsy of at least 15 mm. Discordances of at least two stages between transient elastography and histological assessment were observed in 28 cases (11%). Factors of discordance were assessed by comparing the 28 misclassified cases with the 226 others. In multivariate analysis, fibrosis stage (F0–F2 versus F3–F4) and the ratio interquartile range/median value of liver stiffness measurement (IQR/M) were associated with discordances (P ≤ 0.05). The most significantly discriminant cutoff value was 0.21. For IQR/M < 0.21 versus IQR/M ≥ 0.21, discordances of at least two stages of fibrosis were respectively observed in 10 of 135 cases (7.4%) versus 18 of 119 cases (15.1%) (P ≤ 0.05). In patients with IQR/M ≥ 0.21 versus IQR/M < 0.21, for the diagnosis of liver fibrosis F ≥ 2, F ≥ 3, F = 4, areas under the receiver operating characteristic curve (AUROCs) were 0.80 (95% confidence interval [CI], 0.73–0.89) versus 0.81 (95% CI, 0.70–0.90), (P = NS); 0.80 (95% CI, 0.72–0.88) versus 0.89 (95% CI, 0.83–0.95) (P = 0.04); and 0.86 (95% CI, 0.77–0.94) versus 0.95 (95% CI, 0.92–0.99) (P = NS). No association was found between success rate and discordance. Conclusion: IQR/M is a factor of overestimation of liver fibrosis, and the most discriminant cutoff value is 0.21. Success rate is not a factor of accuracy for the diagnosis of hepatic fibrosis. (Hepatology 2009.)
Hepatitis B virus suppresses toll-like receptor–mediated innate immune responses in murine parenchymal and nonparenchymal liver cells #
Authors: Wu Jun , Meng Zhongji , Jiang Min , Pei Rongjuan , Trippler Martin , Broering Ruth , Bucchi Agnes , Sowa Jan-Peter , Dittmer Ulf , Yang Dongliang , Roggendorf Michael , Gerken Guido , Lu Mengji , Schlaak Joerg F. 
Published: November 2008

Abstract
We have previously shown that Toll-like receptor (TLR)-activated murine nonparenchymal liver cells [(NPC); Kupffer cells (KC), liver sinusoidal endothelial cells (LSEC)] can suppress hepatitis B virus (HBV) replication. Therefore, the aim of this study was to investigate whether HBV has the ability to counteract the TLR-mediated control of its replication. Freshly purified murine hepatocytes and NPCs obtained from C57BL6 mice were stimulated by TLR 1-9 ligands in the presence or absence of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), HBV virions, or supernatants from HBV-producing HBV-Met cells, and HBV replication was suppressed by anti- hepatitis B virus X protein (HBx) small interfering RNA (siRNA) in HBV-Met cells. Supernatants were collected and tested for antiviral cytokines by viral protection assay. HBV gene expression and replication was analyzed by southern blot. RNA and proteins were analyzed by quantitative reverse transcription polymerase chain reaction (RT-PCR) or western blot and enzyme-linked immunosorbent assay, respectively. Pretreatment of hepatocytes and NPCs with HBV-Met cells supernatants, HBsAg, HBeAg, or HBV virions almost completely abrogated TLR-induced antiviral activity, which correlated with suppression of interferon beta (IFN-β) production and subsequent interferon-stimulated gene induction as well as suppressed activation of interferon regulatory factor 3 (IRF-3), nuclear factor kappa B (NF-κB), and extracellular signal-regulated kinase (ERK) 1/2. In HBV-infected HBV-Met cells, TLR stimulation did not induce antiviral cytokines in contrast to primary hepatocytes. TLR-stimulated expression of proinflammatory cytokines [tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6)], and activation of IRF-3 was suppressed after up-regulation of HBV replication in HBV-Met cells. Accordingly, suppression of HBV replication by siRNA led to activation or expression of proinflammatory transcription factors and cytokines. Conclusion: Our data indicate that HBV can suppress the TLR-induced antiviral activity of liver cells. This has major implications for the interaction between HBV and the immune system. (Hepatology 2009.)
Towards a functional organization of the medial temporal lobe memory system: Role of the parahippocampal and medial entorhinal cortical areas
Authors: Eichenbaum Howard , Lipton Paul A. 
Published: November 2008

AbstractWhereas substantial recent evidence has suggested to some that the medial entorhinal cortexá (MEC) plays a specialized role in spatial navigation, here we present evidence consistent with a broader role of the MEC in memory. A consideration of evidence on the anatomy and functional roles of medial temporal cortical areas and the hippocampus, and evidence from recordings from MEC neurons in rats performing a spatial memory task, suggest that the MEC may process information about both spatial and temporal context in support of episodic memory. © 2008 Wiley‐Liss, Inc.
Computation by oscillations: Implications of experimental data for theoretical models of grid cells
Authors: Giocomo Lisa M. , Hasselmo Michael E. 
Published: November 2008

AbstractRecordings in awake, behaving animals demonstrate that cells in medial entorhinal cortex (mEC) show “grid cell” firing activity when a rat explores an open environment. Intracellular recording in slices from different positions along the dorsal to ventral axis show differences in intrinsic properties such as subthreshold membrane potential oscillations (MPO), resonant frequency, and the presence of the hyperpolarization‐activated cation current (h‐current). The differences in intrinsic properties correlate with differences in grid cell spatial scale along the dorsal–ventral axis of mEC. Two sets of computational models have been proposed to explain the grid cell firing phenomena: oscillatory interference models and attractor‐dynamic models. Both types of computational models are briefly reviewed, and cellular experimental evidence is interpreted and presented in the context of both models. The oscillatory interference model has variations that include an additive model and a multiplicative model. Experimental data on the voltage‐dependence of oscillations presented here support the additive model. The additive model also simulates data from ventral neurons showing large spacing between grid firing fields within the limits of observed MPO frequencies. The interactions of h‐current with synaptic modification suggest that the difference in intrinsic properties could also contribute to differences in grid cell properties due to attractor dynamics along the dorsal to ventral axis of mEC. Mechanisms of oscillatory interference and attractor dynamics may make complementary contributions to the properties of grid cell firing in entorhinal cortex. © 2008 Wiley‐Liss, Inc.
Progressive increase in grid scale from dorsal to ventral medial entorhinal cortex
Authors: Brun Vegard Heimly , Solstad Trygve , Kjelstrup Kirsten Brun , Fyhn Marianne , Witter Menno P. , Moser Edvard I. , Moser May‐Britt 
Published: November 2008

AbstractGrid cells are topographically organized in the sense that, within the dorsal part of the medial entorhinal cortex, the scale of the grid increases systematically with anatomical distance from the dorsal border of this brain area. The ventral limit of the spatial map is currently not known. To determine if the grid map extends into the intermediate and ventral parts of the medial entorhinal cortex, we recorded activity from entorhinal principal cells at multiple dorsoventral levels while rats shuttled back and forth on an 18 m long linear track. The recordings spanned a range of more than 3 mm, covering approximately three quarters of the dorsoventral extent of the medial entorhinal cortex. Distinct periodic firing fields were observed at all recording levels. The average interpeak distance between the fields increased from ∼50 cm in the most dorsal part to ∼3 m at the most ventral recording positions. The increase in grid scale was accompanied by a decrease in the frequency of theta modulation and the rate of phase precession. The increase in average spacing and field size was approximately linear but this relationship coincided with a substantial increase in the variability of each measure. Taken together, the observations suggest that the spatial scale of the grid representation increases progressively along most of the dorsoventral axis of the medial entorhinal cortex, mirroring the topographical scale expansion observed in place cells in the hippocampus. © 2008 Wiley‐Liss, Inc.
Conversion of a phase‐ to a rate‐coded position signal by a three‐stage model of theta cells, grid cells, and place cells
Authors: Blair Hugh T. , Gupta Kishan , Zhang Kechen 
Published: November 2008

AbstractAs a rat navigates through a familiar environment, its position in space is encoded by firing rates of place cells and grid cells. Oscillatory interference models propose that this positional firing rate code is derived from a phase code, which stores the rat's position as a pattern of phase angles between velocity‐modulated theta oscillations. Here we describe a three‐stage network model, which formalizes the computational steps that are necessary for converting phase‐coded position signals (represented by theta oscillations) into rate‐coded position signals (represented by grid cells and place cells). The first stage of the model proposes that the phase‐coded position signal is stored and updated by a bank of ring attractors, like those that have previously been hypothesized to perform angular path integration in the head‐direction cell system. We show analytically how ring attractors can serve as central pattern generators for producing velocity‐modulated theta oscillations, and we propose that such ring attractors may reside in subcortical areas where hippocampal theta rhythm is known to originate. In the second stage of the model, grid fields are formed by oscillatory interference between theta cells residing in different (but not the same) ring attractors. The model's third stage assumes that hippocampal neurons generate Gaussian place fields by computing weighted sums of inputs from a basis set of many grid fields. Here we show that under this assumption, the spatial frequency spectrum of the Gaussian place field defines the vertex spacings of grid cells that must provide input to the place cell. This analysis generates a testable prediction that grid cells with large vertex spacings should send projections to the entire hippocampus, whereas grid cells with smaller vertex spacings may project more selectively to the dorsal hippocampus, where place fields are smallest. © 2008 Wiley‐Liss, Inc.
Influence of boundary removal on the spatial representations of the medial entorhinal cortex
Authors: Savelli Francesco , Yoganarasimha D. , Knierim James J. 
Published: November 2008

AbstractThe medial entorhinal cortex (MEC) is thought to create and update a dynamical representation of the animal's spatial location. Most suggestive of this process are grid cells, whose firing locations occur periodically in space. Prior studies in small environments were ambiguous as to whether all spatially modulated cells in MEC were variants of grid cells or whether a subset resembled classic place cells of the hippocampus. Recordings from the dorsal and ventral MEC were performed as four rats foraged in a small square box centered inside a larger one. After 6 min, without removing the rat from the enclosure, the walls of the small box were quickly removed, leaving the rat free to continue foraging in the whole area enclosed by the larger box. The rate‐responses of most recorded cells (70 out of 93 cells, including 15 of 16 putative interneurons) were considered spatially modulated based on information‐theoretic analysis. A number of cells that resembled classic hippocampal place cells in the small box were revealed to be grid cells in the larger box. In contrast, other cells that fired along the boundaries or corners of the small box did not show grid‐cell firing in the large box, but instead fired along the corresponding locations of the large box. Remapping of the spatial response in the area corresponding to the small box after the removal of its walls was prominent in most spatially modulated cells. These results show that manipulation of local boundaries can exert a powerful influence on the spatial firing patterns of MEC cells even when the manipulations leave global cues unchanged and allow uninterrupted, self‐motion‐based localization. Further, they suggest the presence of landmark‐related information in MEC, which might prevent cumulative drift of the spatial representation or might reset it to a previously learned configuration in a familiar environment. © 2008 Wiley‐Liss, Inc.