bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Recognition in Partially Folded States of a Transporter Protein: Temperature‐dependent Specificity of Bovine Serum Albumin
Authors: Banerjee Debapriya , Pal Samir Kumar 
Published: April 2008

AbstractThe specificity of molecular recognition of a transporter protein bovine serum albumin (BSA) in its different partially folded states has been studied. In order to avoid complications due to chemical denaturation, we have prepared thermally induced partially folded states of the protein. The partially folded states have been structurally characterized by circular dichroism and differential thermal analysis techniques. The change in the globular structure of the protein as a consequence of thermal unfolding has also been characterized by dynamic light scattering. Steady state, picosecond‐resolved fluorescence and polarization gated spectroscopies on the ligands (DCM, LDS 750) in the protein reveal the dynamics of the binding sites and the specificity of ligand binding of BSA. Picosecond resolved Förster resonance energy transfer studies on the donor DCM and acceptor LDS 750 confirm that the specificity of ligand binding in the binding site is maintained up to 70°C. At 75°C, the protein loses its specificity of recognition at the aforesaid site.
Spectroscopy, Binding to Liposomes and Production of Singlet Oxygen by Porphyrazines with Modularly Variable Water Solubility
Authors: Sholto Alan , Lee Sangwan , Hoffman Brian M. , Barrett Anthony G. M. , Ehrenberg Benjamin 
Published: April 2008

AbstractThree novel classes of porphyrazine‐like structures were synthesized to form modular structures in which lipophilicity and water solubility can be tuned. Subtle modification of solubility is an important criterion in selecting a compound for biological photosensitization. The general structure takes the form H2[pz(AnB4−n)], where the core is a porphyrazine (pz) group, A is a pyrrole ring with two sulfide linkages (SR moieties) and B is a pyrrole fused with a 4,7‐bis(isopropyloxy)benzo group, with n = 4, 3 and 2. These molecules possess their longest wavelength absorption band between 700 and 810 nm, hence laser beams of higher tissue penetration depth could be used to illuminate them in photodynamic therapy (PDT). Armed with absorption bands in the far‐red and near‐infrared (near‐IR), and a capability to tune the solubility, these molecules could make for better sensitizers because of optimized uptake by lipidic membranes and better optical properties. We tested several derivatives of the A4, A3B and A2B2 structures for their singlet oxygen quantum yields in methanol and in liposomes, using 9,10‐dimethyl anthracene (DMA) as a singlet oxygen target. Singlet oxygen quantum yields in liposomes ranged from 0.01 to 0.44, with the A2B2 group showing the most promise. In the binding assay to find the equilibrium binding constant, Kb, we detected fluorescence changes due to a change in environment. Peripheral long‐chain moieties (the R group in the SR moieties) dominate lipid binding. These moieties range in the hydrophobicity that they induce from C8H17 and benzene, which rendered the molecule totally insoluble in water, to polyethylene glycol (PEG) and carboxylate groups, which imparted water solubility. Each molecule had between 4 and 8 such identical chains. Chains bearing an ether or ester link resulted in measurable equilibrium constants, with a higher Kb for ether substituents. Results for Kb ranged from 0.23 to 26.52 (mg mL−1)−1. A delicate balance exists between water solubility and good partitioning to membranes. In general, a higher oxygen‐to‐carbon ratio in the chains improves binding. Fewer chains and a centrally coordinated zinc ion further improve binding and singlet oxygen production.
Immunophototherapy Using PDT Combined with Rapid Intratumoral Dendritic Cell Injection
Authors: Sur Brandon W. , Nguyen Phuong , Sun Chung‐Ho , Tromberg Bruce J. , Nelson Edward L. 
Published: April 2008

AbstractThe capacity of photodynamic therapy (PDT) to induce localized cell death and tissue damage suggests that when applied to tumors it could create a local depot of tumor‐associated antigens, which would be available for uptake and presentation to the immune system, potentially leading to improved tumor control. Dendritic cells (DCs) are the most potent cells for antigen uptake, presentation, and stimulation of the immune system. However, it is unclear whether DCs would retain their viability and functional capacity for the requisite trafficking to draining lymph nodes when adoptively transferred in close temporal and anatomic proximity to the site of PDT‐induced cytotoxicity. We conducted studies of combined PDT and adoptive DC therapy, “immunophototherapy,” in a female, Fisher 344 rat orthotopic mammary tumor model. Using 5‐aminolevulinic acid as a pro‐drug, we demonstrated kinetically favorable biologic conversion to the photosensitive protoporphyrin IX, appropriate trafficking of syngeneic bone marrow‐derived DCs injected into PDT‐treated tumors within 15 min of completion of therapy, and improved survival over either modality alone. These data indicate that DCs rapidly administered into the site of PDT retain their viability and functional status, supporting the further evaluation of immunophototherapy strategies.
Human Natures: Psychological Essentialism in Thinking about Differences between People
Authors: Haslam Nick , Whelan Jennifer 
Published: April 2008

Abstract‘Psychological essentialism’ is the belief that members of a category share deep‐seated properties that determine their identity. In the case of social categories, such beliefs have a variety of important implications. We review recent research that shows a central role for essentialist thinking in stereotyping, prejudice, and discrimination. Special attention is paid to beliefs about race and ethnicity, gender, sexual orientation, mental disorder, and personality. Lingering questions about essentialist thinking are discussed, and several directions for future research are suggested.
Phenomenology and Critical Social Psychology: Directions and Debates in Theory and Research
Authors: Langdridge Darren 
Published: April 2008

AbstractThere has been significant growth in critical approaches to social psychology in recent years. Phenomenological, discursive and psychoanalytically informed perspectives, amongst others, have become increasingly popular alternatives to ‘mainstream’ cognitive social psychology. This paper describes the fundamental philosophy and methodology underpinning phenomenological psychology along with discussion of a number of key issues in qualitative research in social psychology. In particular, I discuss the role of interpretation, the turn to language and need for political engagement within critical social psychology. More recently, there has been a growth in phenomenologically informed narrative theories and methodologies and in this paper I introduce my own development of a critical narrative analysis. In the process I discuss some of the most pressing debates about research within the phenomenological tradition and provide rebuttals, solutions and possible future directions for phenomenological theory and research that may lead to yet greater recognition for this social psychological perspective.
Prognostic value of mitotic counts and Ki-67 immunoreactivity in adult-type granulosa cell tumour of the ovary
Authors: Leuverink E M , Brennan B A , Crook M L , Doherty D A , Hammond I G , Ruba S , Stewart C J R 
Published: April 2008

Aims:The identification of reliable prognostic factors in patients with ovarian stage 1 adult-type granulosa cell tumour (GCT) has proved problematic. Some reports have suggested that proliferation indices may be of value, but the data are conflicting and the methods of assessment often poorly defined. In this study the mitotic activity and Ki-67 immunohistochemistry was assessed in a series of GCT using carefully specified methodology, and the findings were correlated with clinicopathological findings.Methods:Tumour proliferation was assessed in 38 primary GCT by counting mitotic figures in 50 high-power fields (×500 magnification) with results expressed as a mean count per 2 mm2standardised area. The number of mitotic figures and Ki-67 immunoreactive cells per 10 000 tumour cells was also assessed using an ocular cell counting graticule. The results were correlated with tumour stage at presentation and with the development of tumour recurrence.Results:Twenty-nine patients were stage 1 at presentation, and nine patients had high-stage disease (extra-ovarian spread). Nine patients with initial stage 1 disease developed metastases, and 20 patients had no evidence of recurrence over a mean follow-up period of 11.1 years. There was no significant correlation between any of the proliferation indices or with clinical outcomes.Conclusions:These results suggest that proliferation assessment is of limited value in the pathological assessment of GCT. Future studies should carefully specify the methods of assessing cell proliferation to ensure a reliable comparison of results.
Failed predation in Late Ordovician gastropods (Mollusca) from Manitoulin Island, Ontario, CanadaThis article is one of a selection of papers published in this Special Issue on the themeThe dynamic reef and shelly communities of the Paleozoic. This Special is in honour of our colleague and friend Paul Copper.
Authors: Ebbestad Jan Ove R. , Stott Christopher A. 
Published: April 2008

Shell repairs resulting from presumed failed predation are documented in gastropods from the Late Ordovician (Cincinnatian; Richmondian) mid-to-upper Kagawong Submember of the Georgian Bay Formation on Manitoulin Island, Ontario, Canada. The bryozoan–mollusc biota and associated sediments generally suggest nearshore, shallow (<10 m), low energy (lagoonal), and perhaps mesotrophic to eutrophic conditions. Two sample sets from this unit have been studied for shell repair. One of the more commonly applied estimates of shell repair frequencies involves division of the number of individuals with at least one scar by the total number of individuals in the sample (the Individuals with scars method). Using this calculation, 207 specimens of Lophospira trilineata Ulrich and Scofield yielded a shell repair frequency of 4.8%; in 28 specimens of Trochonemella sp. the shell repair frequency was 35.7%. Repairs in Trochonemella occur primarily in the larger size class, suggesting that a size refuge was achieved by this species. Low repair frequencies in L. trilineata suggest predation with a higher success rate or fewer encounters. This study demonstrates that the paradigm of a standardized low level of shell repair in Ordovician and Silurian gastropods is oversimplistic and a range of frequency rates can be expected.
Reduction of enantioselectivity in the kinetic disposition and metabolism of verapamil in rats exposed to toluene
Authors: Mateus F.H. , Lepera J.S. , Marques M.P. , Boralli V.B. , Lanchote V.L. 
Published: April 2008

Toluene and verapamil are subject to extensive oxidative metabolism mediated by CYP enzymes, and their interaction can be stereoselective. In the present study we investigated the influence of toluene inhalation on the enantioselective kinetic disposition of verapamil and its metabolite, norverapamil, in rats. Male Wistar rats (n = 6 per group) received a single dose of racemic verapamil (10 mg/kg) orally at the fifth day of nose-only toluene or air (control group) inhalation for 6 h/day (25, 50, and 100 ppm). Serial blood samples were collected from the tail up to 6 h after verapamil administration. The plasma concentrations of verapamil and norverapamil enantiomers were analyzed by LC-MS/MS by using a Chiralpak AD column. Toluene inhalation did not influence the kinetic disposition of verapamil or norverapamil enantiomers (p > 0.05, Kruskal–Wallis test) in rats. The pharmacokinetics of verapamil was enantioselective in the control group, with a higher plasma proportion of the S-verapamil (AUC 250.8 versus 120.4 ng·h·mL–1; p ≤ 0.05, Wilcoxon test) and S-norverapamil (AUC 72.3 versus 52.3 ng·h·mL–1; p ≤ 0.05, Wilcoxon test). Nose-only exposure to toluene at 25, 50, or 100 ppm resulted in a lack of enantioselectivity for both verapamil and norverapamil. The study demonstrates the importance of the application of enantioselective methods in studies on the interaction between solvents and chiral drugs.
Modulation of radiosensitivity in Chinese hamster lung fibroblasts by cisplatin
Authors: Akudugu J.M. , Slabbert J.P. 
Published: April 2008

The effects of cisplatin exposure time, concentration, and irradiation sequence on the sensitivity of Chinese hamster lung fibroblasts (V79) to γ-ray exposure were examined. Based on clonogenic cell survival, the cisplatin concentrations corresponding to 50% cell survival (EC50) for exposure times of 1 h to 7 days followed a 2-phase exponential decay and ranged from 28.26 ± 3.32 to 1.53 ± 0.24 μmol/L, respectively. When cells were treated at EC50 for exposures of less than 4 h and irradiated immediately, cisplatin inhibited the effect of radiation. Exposures of 4–6 h did not affect radiosensitivity. For exposures of 8–12 h, radiosensitization was observed, which disappeared at 14 h and reappeared for much longer cisplatin treatments. At the lowest achievable EC50 (1.53 μmol/L), radiosensitization was observed if irradiation was delayed for 1–8 h. This enhancement in radiosensitivity disappeared for irradiation delays of 10–12 h, but reappeared when irradiation was delayed for 14–18 h. These data demonstrate that the mode of interaction between cisplatin and γ-irradiation depends on the concentration and exposure time of cisplatin, as well as on the timing of irradiation after cisplatin administration. Consideration of changes in cell cycle kinetics may contribute to the improvement of treatment outcomes in adjuvant chemoradiotherapy involving cisplatin.
Increase in extracellular dopamine levels during clozapine-induced potentiation in the hippocampal dentate gyrus of chronically prepared rabbits
Authors: Kubota Takashi , Jibiki Itsuki , Ishikawa Akira , Kawamura Tomomi , Kurokawa Sonoko , Wang Man 
Published: April 2008

We previously found that 20 mg/kg clozapine i.p. potentiated the excitatory synaptic responses elicited in the dentate gyrus by single electrical stimulation of the perforant path in chronically prepared rabbits. We called this phenomenon clozapine-induced potentiation and proved that it was an NMDA receptor-mediated event. This potentiation is presumably related to clozapine’s clinical effect on negative symptoms and cognitive dysfunctions in schizophrenia. In the present study, to investigate the mechanisms underlying clozapine-induced potentiation, we examined whether extracellular dopamine and 5-HT levels changed during the potentiation by using a microdialysis technique in the dentate gyrus. The extracellular concentrations of dopamine and 5-HT levels were measured every 5 min during all experiments. Extracellular 5-HT levels did not change, but dopamine levels eventually increased significantly during clozapine-induced potentiation. The increase in the dopamine levels occurred almost simultaneously with the induction of clozapine-induced potentiation. These results suggest that clozapine-induced potentiation is at least partly attributable to a dopamine-mediated potentiation of excitatory synaptic transmission. The present study implies that such phenomena occur also in the perforant path–dentate gyrus pathway.
The Relationship between the Southern Hemisphere Annular Mode and Antarctic Peninsula Summer Temperatures: Analysis of a High-Resolution Model Climatology
Authors: van Lipzig Nicole P. M. , Marshall Gareth J. , Orr Andrew , King John C. 
Published: April 2008

Abstract
The large regional summer warming on the east coast of the northern Antarctic Peninsula (AP), which has taken place since the mid-1960s, has previously been proposed to be caused by a trend in the Southern Hemisphere Annular Mode (SAM). The authors utilize a high-resolution regional atmospheric model climatology (14-km grid spacing) to study the mechanisms that determine the response of the near-surface temperature to an increase in the SAM (ΔT/ΔSAM). Month-to-month variations in near-surface temperature and surface pressure are well represented by the model. It is found that north of ∼68°S, ΔT/ΔSAM is much larger on the eastern (lee) side than on the western (windward) side of the barrier. This is because of the enhanced westerly flow of relatively warm air over the barrier, which warms (and dries) further as it descends down the lee slope. The downward motion on the eastern side of the barrier causes a decrease in surface-mass balance and cloud cover. South of ∼68°S, vertical deflection across the barrier is greatly reduced and the contrast in ΔT/ΔSAM between the east and west sides of the barrier vanishes. In the northeastern part of the AP, the modeled ΔT/ΔSAM distribution is similar to the distribution derived from satellite infrared radiometer data. The region of strongest modeled temperature sensitivity to the SAM is where ice shelf collapse has recently taken place and does not extend farther south over the Larsen-C Ice Shelf.
A Hidden Markov Model Perspective on Regimes and Metastability in Atmospheric Flows
Authors: Franzke Christian , Crommelin Daan , Fischer Alexander , Majda Andrew J. 
Published: April 2008

AbstractIn this study, data from three atmospheric models are analyzed to investigate the existence of atmospheric flow regimes despite nearly Gaussian statistics of the planetary waves in these models. A hierarchy of models is used, which describes the atmospheric circulation with increasing complexity. To systematically identify atmospheric regimes, the presence of metastable states in the data is searched for by fitting so-called hidden Markov models (HMMs) to the time series.A hidden Markov model is designed to describe the situation in which part of the information of the system is unknown or hidden and another part is observed. Within the context of this study, some representative variable of planetary-scale flow (e.g., mean zonal flow or leading principal component) is known (“observed”), but its dynamics may depend crucially on the overall flow configuration, which is unknown. The behavior of this latter, “hidden” variable is described by a Markov chain. If the Markov chain possesses metastable (or quasi persistent) states, they are identified as regimes. In this perspective, regimes can be present even though the observed data have a nearly Gaussian probability distribution. The parameters of the HMMs are fit to the time series using a maximum-likelihood approach; well-established and robust numerical methods are available to do this. Possible metastability of the Markov chain is assessed by inspecting the eigenspectrum of the associated transition probability matrix. The HMM procedure is first applied to data from a simplified model of barotropic flow over topography with a large-scale mean flow. This model exhibits regime behavior of its large-scale mean flow for sufficiently high topography. In the case of high topography, the authors find three regimes, two of which correspond to zonal flow and the third to blocking.Next, a three-layer quasigeostrophic model is used as a prototype atmospheric general circulation model (GCM). Its first empirical orthogonal function (EOF) is similar to the Arctic Oscillation (AO) and exhibits metastability. For this model, two regime states are found: one corresponding to the positive phase of the AO with large amplitude and decreased variability of the streamfunction field, and another corresponding to the negative AO phase with small amplitude and increased variability. Finally, the authors investigate a comprehensive GCM. The leading four EOFs of this model show no signs of metastability. The results of the barotropic flow over topography and of the quasigeostrophic model suggest that the observed small skewness of planetary wave probability density functions (PDFs) is an imprint of blocked circulation states.
Mechanism of the Asymmetric Monsoon Transition as Simulated in an AGCM
Authors: Wang Zhuo , Chang C-P. 
Published: April 2008

Abstract
Atmospheric general circulation model (AGCM) simulations are carried out to test a hypothesis (Chang et al.) for the asymmetric monsoon transition in which the maximum convection marches gradually from the Asian summer monsoon to the Asian winter monsoon during boreal fall but experiences a sudden transition in the reverse during boreal spring. In the control run, the AGCM is driven by the climatological mean sea surface temperature (SST) with a realistic annual cycle, and it reproduces the observed asymmetric monsoon transition. In the sensitivity test, the model is driven by a similarly realistic SST but whose annual cycle is symmetric. The northwestward march of the maximum convection in boreal spring becomes more gradual, resulting in an overall near-symmetric pattern for the monsoon seasonal transition. The AGCM simulations confirm the hypothesis that the atmospheric mass redistribution due to the different land–ocean thermal memories leads to a seasonally different horizontal convergence field and it facilitates the southeastward monsoon march in boreal fall, while it hinders the northwestward monsoon march in boreal spring, contributing to the asymmetric monsoon transition.
A Comparison Study of Three Polar Grids
Authors: Chen Tsing-Chang , Tsay Jenq-Dar , Gutowski William J. 
Published: April 2008

Abstract
The circumference of a latitude circle decreases toward the Poles, making it difficult to present meteorological field variables on equally spaced grids with respect to latitude and longitude because of data aggregation. To identify the best method for displaying data at the Poles, three different grids are compared that have all been designed to reduce data aggregation: the reduced latitude–longitude (RL) grid, the National Snow and Ice Data Center Equal-Area Special Sensor Microwave Imager (SSM/I) Earth (EA) grid, and the National Meteorological Center octagonal (OG) grid. The merits and disadvantages of these grids are compared in terms of depictions of the Arctic summer circulation with wind vectors, streamfunction, and velocity potential at 400 hPa where maximum westerlies are located. Using geostrophy, the 400-hPa streamfunction at high latitudes can be formed from geopotential height. In comparison with this geostrophic streamfunction, the streamfunction generated from vorticity on the OG grid shows a negligible error (∼0.5%). The error becomes larger using vorticity on the EA (∼15%) and RL (∼30%) grids. During the northern summer, the Arctic circulation at 400 hPa is characterized by three troughs. The streamfunction and velocity potential of these three troughs are spatially in quadrature with divergent (convergent) centers located ahead of (behind) these troughs. These circulation features are best depicted by the streamfunction and velocity potential generated on the OG grid. It is demonstrated by these findings that the National Meteorological Center octagonal grid is the most ideal among the three grids used for the polar regions. However, this assessment is constrained by the hemispheric perspective of meteorological field variables, because these variables depicted on the octagonal grid at higher latitudes need to be merged with those on the equal-latitude-longitude grid at lower latitudes.