bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetic Analysis of the SpeciesTheilovirus: Emerging Murine and Human Pathogens
Authors: Liang Zhiguo , Kumar A. S. Manoj , Jones Morris S. , Knowles Nick J. , Lipton Howard L.
Published: September 2008

TheCardiovirusgenus of the familyPicornaviridaeincludes two distinct species,Encephalomyocarditis virusandTheilovirus. We now report the complete nucleotide sequences of three Theiler's murine encephalomyelitis virus (TMEV) strains (TO Yale, TOB15, and Vie 415HTR) and of Vilyuisk human encephalomyelitis virus (VHEV). This information, together with the recently reported sequences of divergent theiloviruses (Theiler's-like rat virus [TRV] and Saffold viruses 1 and 2 [SAFV-1 and SAFV-2]), enables an updated phylogenetic analysis as well as a reexamination of several gene products important in the pathogenesis of this emerging group of viruses. In the light of the known neurotropism of TMEV and the new human SAFV-1 and SAFV-2, the resulting data suggest the existence of theiloviruses that cause human central nervous system infections. Our phylogenetic analyses point to the classification of presently known theiloviruses into five types: TMEV, VHEV, TRV, SAFV-1, and SAFV-2.
Cellular Transcription Factors Sp1 and Sp3 Suppress Varicella-Zoster Virus Origin-Dependent DNA Replication
Authors: Khalil Mohamed I. , Hay John , Ruyechan William T.
Published: September 2008

The varicella-zoster virus (VZV) origin of DNA replication (oriS) contains a 46-bp AT-rich palindrome and three consensus binding sites for the VZV origin binding protein (OBP) encoded by VZV ORF51. All three OBP binding sites are upstream of the palindrome in contrast to the sequence of the herpes simplex virus oriS, which has required OBP binding sites upstream and downstream of the AT-rich region. We are investigating the roles that sequences downstream of the palindrome play in VZV oriS-dependent DNA replication. Computer analysis identified two GC boxes, GC box 1 and GC box 2, in the downstream region which were predicted to be binding sites for the cellular transcription factor Sp1. Electrophoretic mobility shift assay and supershift assays showed that two members of the Sp family (Sp1 and Sp3) stably bind to GC box 1, but not to GC box 2. A predicted binding site for the cellular factor Yin Yang 1 (YY1) that overlaps with GC box 2 was also identified. Supershift and mutational analyses confirmed the binding of YY1 to this site. Mutation of GC box 1 resulted in loss of Sp1 and Sp3 binding and an increase in origin-dependent replication efficiency in DpnI replication assays. In contrast, mutation of the YY1 site had a statistically insignificant effect. These results suggest a model where origin-dependent DNA replication and viral transcription are coupled by the binding of Sp1 and Sp3 to the downstream region of the VZV replication origin during lytic infection. They may also have implications regarding establishment or reactivation of viral latency.
Crystal Structure and Carbohydrate Analysis of Nipah Virus Attachment Glycoprotein: a Template for Antiviral and Vaccine Design
Authors: Bowden Thomas A. , Crispin Max , Harvey David J. , Aricescu A. Radu , Grimes Jonathan M. , Jones E. Yvonne , Stuart David I.
Published: September 2008

Two members of the paramyxovirus family, Nipah virus (NiV) and Hendra virus (HeV), are recent additions to a growing number of agents of emergent diseases which use bats as a natural host. Identification of ephrin-B2 and ephrin-B3 as cellular receptors for these viruses has enabled the development of immunotherapeutic reagents which prevent virus attachment and subsequent fusion. Here we present the structural analysis of the protein and carbohydrate components of the unbound viral attachment glycoprotein of NiV glycoprotein (NiV-G) at a 2.2-Å resolution. Comparison with its ephrin-B2-bound form reveals that conformational changes within the envelope glycoprotein are required to achieve viral attachment. Structural differences are particularly pronounced in the 579-590 loop, a major component of the ephrin binding surface. In addition, the 236-245 loop is rather disordered in the unbound structure. We extend our structural characterization of NiV-G with mass spectrometric analysis of the carbohydrate moieties. We demonstrate that NiV-G is largely devoid of the oligomannose-type glycans that in viruses such as human immunodeficiency virus type 1 and Ebola virus influence viral tropism and the host immune response. Nevertheless, we find putative ligands for the endothelial cell lectin, LSECtin. Finally, by mapping structural conservation and glycosylation site positions from other members of the paramyxovirus family, we suggest the molecular surface involved in oligomerization. These results suggest possible pathways of virus-host interaction and strategies for the optimization of recombinant vaccines.
The Proto-Oncogene Bcl3, Induced by Tax, Represses Tax-Mediated Transcription via p300 Displacement from the Human T-Cell Leukemia Virus Type 1 Promoter
Authors: Kim Young-Mi , Sharma Neelam , Nyborg Jennifer K.
Published: September 2008

The etiology of human T-cell leukemia virus type 1 (HTLV-1)-induced adult T-cell leukemia is linked to the expression of the viral oncoprotein Tax. Although the mechanism of retroviral transformation is unknown, Tax interferes with fundamental cellular processes, including proliferation and apoptosis, and these events may directly link Tax to early steps in malignant progression. In this study, we examined the interplay between Tax and the potent proto-oncogene
B
-cell
c
hronic
l
eukemia protein
3
(Bcl3). Bcl3 is a critical regulator of cell survival and proliferation and is overexpressed in HTLV-1-infected cells. We found that Tax induced Bcl3 expression through stimulation of the NF-κB pathway. An intronic NF-κB binding site within the Bcl3 gene served as the primary target of Tax-induced NF-κB activation. We next considered the consequence of Bcl3 overexpression on Tax function. Interestingly, we found that Bcl3 formed a stable complex with Tax and that this complex potently inhibited Tax-dependent HTLV-1 transcription. Importantly, Bcl3 associated with the HTLV-1 promoter in a Tax-dependent manner and inhibited the binding of the critical cellular coactivator p300. The conserved ankyrin repeat domain of Bcl3 mediated both Tax binding and inhibition of p300 recruitment to the HTLV-1 promoter. Together, these data suggest that Tax-induced Bcl3 overexpression benefits the virus in two important ways. First, Bcl3 may promote cell division and thus clonal proliferation of the virus. Second, Bcl3 may attenuate virion production, facilitating immune evasion. One consequence of this regulatory loop may be Bcl3-induced malignant transformation of the host cell.
Interaction of Parvovirus B19 with Human Erythrocytes Alters Virus Structure and Cell Membrane Integrity
Authors: Bönsch Claudia , Kempf Christoph , Ros Carlos
Published: September 2008

The unique region of the capsid protein VP1 (VP1u) of B19 virus (B19V) elicits a dominant immune response and has a phospholipase A
2
(PLA
2
) activity required for the infection. Despite these properties, we have observed that the VP1u-PLA
2
motif occupies an internal position in the capsid. However, brief exposure to increasing temperatures induced a progressive accessibility of the PLA
2
motif as well as a proportional increase of the PLA
2
activity. Similarly, upon binding on human red blood cells (RBCs), a proportion of the capsids externalized the VP1u-PLA
2
motif. Incubation of B19V with RBCs from 17 healthy donors resulted in extensive virus attachment ranging between 3,000 and 30,000 virions per cell. B19V empty capsids represent an important fraction of the viral particles circulating in the blood (30 to 40%) and bind to RBCs in the same way as full capsids. The extensive B19V binding to RBCs did not cause direct hemolysis but an increased osmotic fragility of the cells by a mechanism involving the PLA
2
activity of the exposed VP1u. Analysis of a blood sample from an individual with a recent B19V infection revealed that, at this particular moment of the infection, the virions circulating in the blood were mostly associated to the RBC fraction. However, the RBC-bound B19V was not able to infect susceptible cells. These observations indicate that RBCs play a significant role during B19V infection by triggering the exposure of the immunodominant VP1u including its PLA
2
constituent. On the other hand, the early exposure of VP1u might facilitate viral internalization and/or uncoating in target cells.
Smuggling as the “key to a combined market”: British American Tobacco in Lebanon
Authors: Nakkash R , Lee K
Published: September 2008

Objectives:

To understand the strategy of British American Tobacco (BAT) and other transnational tobacco companies (TTCs) to gain access to the Lebanese market, which has remained relatively closed under monopoly ownership and political instability.

Methods:

Analysis of internal industry documents, local language secondary sources and industry publications.

Results:

TTCs have relied on legal and illegal channels to supply the Lebanese market since at least the 1970s. Available documents suggest smuggling has been an important component of BAT’s market entry strategy, transported in substantial quantities via middlemen for sale in Lebanon and neighbouring countries. TTCs took advantage of weak and unstable governance, resulting in uncertainty over the Regie’s legal status, and continued to supply the contraband trade despite appeals by the government to cease undermining its revenues. Since the end of the civil war in the early 1990s, continued uncertainty about the tobacco monopoly amid political instability has encouraged TTCs to seek a legal presence in the country, while continuing to achieve substantial sales through contraband.

Conclusion:

Evidence of the complicity of TTCs in cigarette smuggling extends to Lebanon and the Middle East where this trade has especially benefited from weak governance and chronic political instability. The regional nature of TTC strategy supports strong international cooperation under the Framework Convention on Tobacco Control to tackle the problem.
Nutrient Regeneration in Deep Baffin Bay with Consequences for Measurements of the Conservative Tracer NO and Fossil Fuel CO2 in the Oceans
Authors: Jones E. P. , Dyrssen D. , Coote A. R.
Published: September 2008

We found the nitrate to phosphate ratio of nutrients regenerated in Baffin Bay to be lower than is typical of most other ocean regions. The conservative tracers NO and PO are constant for water below 500 m providing NO and PO are redefined to account for this different nitrogen to phosphate ratio in the decaying organic matter of Baffin Bay. A modified stoichiometric model for decaying organic material in Baffin Bay was constructed based on measured values of carbonate, nitrate, and phosphate. A major difficulty in assessing the amount of fossil fuel CO2 in the ocean is the determination of the amount of inorganic carbon produced during the decay of biogenic material. Using the modified stoichiometric model for decaying biogenic material, we show how regional and seasonal variations in the amount of carbon released and oxygen consumed during decay could be sufficiently different from what is predicted by the Redfield–Ketchum–Richards model to cause major differences in the assessment of the amount of fossil fuel CO2 present in the water. The modified stoichiometric model offers the opportunity to determine the oxygen–carbon relationships more accurately and to obtain better estimates of fossil fuel CO2 in the ocean.
Planktonic Communities in Florida Softwater Lakes of Varying pH
Authors: Brezonik Patrick L. , Crisman Thomas L. , Schulze Randy L.
Published: September 2008

In 20 softwater Florida lakes (pH range 4.7–6.8), phytoplankton diversity was significantly higher in the less acidic lakes; mean numbers of species in two groups (1, pH < 5.3; 2, pH > 5.6), each consisting of 10 lakes, was 10.8 and 16.5, respectively. Blue-green algae were dominant in less acidic lakes, while green algae were the most common group in acidic lakes. Phytoplankton abundance also was lower in acidic lakes, but covariation of phosphorus concentrations with pH confounded interpretation. Trends in zooplankton communities along the pH gradient were less pronounced. More acidic lakes had more species than the less acidic lakes, but three measures of species diversity showed no significant differences between the two groups. Zooplankton abundance was lower in the acidic lakes, but the relationship between abundance and pH showed much scatter. Lake productivity probably affects zooplankton abundance more than pH does in the sample group. No clear trends were observed in relative abundance of major zooplankton groups across the pH gradient. Six acid-tolerant species (including Diaptomus floridanus, Eubosmina tubicen, and Daphnia ambigua) were dominant in all 20 lakes.
A Cost-Benefit Method for Determining Optimum Closed Fishing Areas to Reduce the Trawl Catch of Prohibited Species
Authors: Somerton David A. , June Jeffrey
Published: September 2008

Red king crab (Paralithodes camtschatica), a prohibited species, are incidentally caught by United States trawl fisheries for yellowfin sole (Limanda aspera) and other groundfish in the eastern Bering Sea. To reduce this incidental catch, we propose a method for determining a king crab conservation zone where trawling would be prohibited. This method considers the gross revenue potentially gained by the yellowfin sole fishery and lost by the king crab fishery by allowing trawling in each of a number of equal-size areas. Utilizing exvessel prices and research survey estimates of species densities, areas are assigned relative values equal to the value of groundfish minus the value of king crab. By including all areas with negative relative values in the conservation zone, the potential gross revenue that could be obtained from the groundfish and king crab resource is maximized.
Parr-Smolt Transformation of Atlantic Salmon (Salmo salar): Activities of Two Respiratory Enzymes and Concentrations of Mitochondria in the Liver
Authors: Blake Robert L. , Roberts Franklin L. , Saunders Richard L.
Published: September 2008

Hatchery-reared parr and smolts of Atlantic salmon (Salmo salar) derived from spawners of the Big Salmon, Saint John, and Penobscot rivers were analyzed for activity of two respiratory chain enzymes in liver. Cytochrome c oxidase activity was about 15-fold greater in enzyme units than succinate dehydrogenase in all three experimental groups. Smolt sample means for cytochrome c oxidase and succinate dehydrogenase in Big Salmon and Saint John fish were significantly greater than those of parr. Measurements in Big Salmon fish, which had the greatest parr–smolt difference in cytochrome c oxidase units and condition factor, demonstrated a significantly greater smolt sample mean for liver mitochondria concentrations. The results are discussed primarily in relation to the possible role of thyroid hormone in causing a greater potential for aerobic energy generation in liver during smoltification and the utilization of lipid as an energy resource.
An Index of the Relative Abundance of Wintering Belugas,Delphinapterus leucas, and Narwhals,Monodon monoceros, off West Greenland
Authors: Heide-Jørgensen M. P. , Lassen H. , Teilmann J. , Davis R. A.
Published: September 2008

Systematic aerial surveys of the wintering grounds of belugas, Delphinapterus leucas, and narwhals, Monodon monoceros, in southern Baffin Bay and northern Davis Strait were conducted in late winter of 1981, 1982, 1990, and 1991. Most belugas were found between 67°N and 69°N and none were seen more than 80 km off the coast of West Greenland. Compared with the surveys in 1981 and 1982, a decline in relative abundance of belugas along West Greenland was evident in 1991. This decline was significant at a probability level of 0.13 of the bootstrapped distribution of the combined abundance estimate. Pod sizes declined significantly between the 1981–82 and 1990–91 surveys. The variations in ice conditions between years did not seem to affect the distribution, clumping, or pod sizes of the belugas. Narwhals were widely distributed in the close pack ice offshore between 65°N and 72°N. Along the West Greenland coast, narwhals were primarily seen at the mouth of Disko Bay. No change in relative abundance or pod sizes could be detected for narwhals.
RENORMALIZED QUANTUM YANG–MILLS FIELDS IN CURVED SPACETIME
Authors: HOLLANDS STEFAN
Published: September 2008

We present a proof that the quantum Yang–Mills theory can be consistently defined as a renormalized, perturbative quantum field theory on an arbitrary globally hyperbolic curved, Lorentzian spacetime. To this end, we construct the non-commutative algebra of observables, in the sense of formal power series, as well as a space of corresponding quantum states. The algebra contains all gauge invariant, renormalized, interacting quantum field operators (polynomials in the field strength and its derivatives), and all their relations such as commutation relations or operator product expansion. It can be viewed as a deformation quantization of the Poisson algebra of classical Yang–Mills theory equipped with the Peierls bracket. The algebra is constructed as the cohomology of an auxiliary algebra describing a gauge fixed theory with ghosts and anti-fields. A key technical difficulty is to establish a suitable hierarchy of Ward identities at the renormalized level that ensures conservation of the interacting BRST-current, and that the interacting BRST-charge is nilpotent. The algebra of physical interacting field observables is obtained as the cohomology of this charge. As a consequence of our constructions, we can prove that the operator product expansion closes on the space of gauge invariant operators. Similarly, the renormalization group flow is proved not to leave the space of gauge invariant operators. The key technical tool behind these arguments is a new universal Ward identity that is formulated at the algebraic level, and that is proven to be consistent with a local and covariant renormalization prescription. We also develop a new technique to accomplish this renormalization process, and in particular give a new expression for some of the renormalization constants in terms of cycles.
PARTIALIZATION OF CATEGORIES AND INVERSE BRAID-PERMUTATION MONOIDS
Authors: KUDRYAVTSEVA GANNA , MAZORCHUK VOLODYMYR
Published: September 2008

We show how one can use the partialization functor to obtain several recently defined inverse monoids, and use this functor to define new objects, which we call the inverse braid-permutation monoids. A presentation for this monoid is obtained. Finally, we study some abstract properties of the partialization functor and its iterations. This leads to a categorification of a monoid of all order-preserving maps, and series of orthodox generalizations of the symmetric inverse semigroup.
TROPICAL ALGEBRAIC SETS, IDEALS AND AN ALGEBRAIC NULLSTELLENSATZ
Authors: IZHAKIAN ZUR
Published: September 2008

This paper introduces the foundations of the polynomial algebra and basic structures for algebraic geometry over the extended tropical semiring. Our development, which includes the tropical version for the fundamental theorem of algebra, leads to the reduced polynomial semiring — a structure that provides a basis for developing a tropical analogue to the classical theory of commutative algebra. The use of the new notion of tropical algebraic com-sets, built upon the complements of tropical algebraic sets, eventually yields the tropical algebraic Nullstellensatz.
COMPUTER-BASED IDENTIFICATION OF PLANTAR PRESSURE IN TYPE 2 DIABETES SUBJECTS WITH AND WITHOUT NEUROPATHY
Authors: ACHARYA U. RAJENDRA , RAHMAN MUHAMMAD AFIQ , AZIZ ZULKARNAIN , TAN PECK HA , NG E. Y. K. , YU WENWEI , LAW CHELSEA , SUBRAMANIAM TAVINTHARAN , WONG YUE SHUEN , SUM CHEE FANG
Published: September 2008

Diabetes mellitus is a medical disorder characterized by varying or persistent hyperglycemia (elevated blood sugar levels), especially after eating. People with diabetes have problems converting food to energy. The most common form of diabetes is type 2 diabetes. Foot disease is a common complication of diabetes that can have tragic consequences. Abnormal plantar pressures are considered to play a major role in the pathologies of neuropathic ulcers in the diabetic foot. The purpose of this study was to classify the plantar pressure distribution in normal and type 2 diabetes subjects with and without neuropathy. Foot scans were obtained using the F-Scan (Tekscan, USA) in-shoe pressure measurement system. Various pedobarographic parameters such as the total plantar force, total contact area, peak pressures, and percentage medial impulse (PMI) were evaluated. These parameters were subjected to analysis of variance (ANOVA) test with a >95% confidence interval, giving excellent p-values in all of the categories. When these extracted parameters were presented to the artificial neural network (ANN) for classification, the neural network classifier was seen to be correct in more than 90% of the test cases.
VIRTUAL PROPRIOCEPTION
Authors: LEMOYNE ROBERT , COROIAN CRISTIAN , MASTROIANNI TIMOTHY , GRUNDFEST WARREN
Published: September 2008

Virtual proprioception represents a novel means of developing cortical reorganization of alternative strategies for hemiparetic gait. Fundamentals of the device are motor control plasticity, aftereffect, and visual-based biofeedback. Two wireless three-dimensional (3D) microelectromechanical systems (MEMS) accelerometers are placed on the femur (upper leg) of both the affected and unaffected limbs above the lateral epicondyle next to the knee joint. The acceleration data from the two wireless 3D MEMS accelerometers are fed back to the user in real time by visual output from a portable laptop PC. Given the virtual proprioception feedback, the user can then adjust the original gait while walking to an improved alternative gait strategy. First, hemiparetic gait is comprehensively discussed. The inherent roles of proprioception with locomotion and issues with traumatic brain injury are considered. Then, the technology advance of accelerometers and gait analysis is detailed. Virtual proprioception is tested and evaluated, while demonstrating the capacity to improve disparities in hemiparetic gait during real time.
FLOW VISUALIZATION IN RIGHT CORONARY ARTERY BYPASS MODELS
Authors: SINGH M. , LIEPSCH D. , McLEAN JOYCE , PALLOTTI G.
Published: September 2008

It is well known from fundamental fluid mechanics that separation regions occur at bends and bifurcations of blood vessels. In addition to this, a secondary flow is also created. This means that the flow is moving forward like a vortical plait. Vortices are created that move counterclockwise to each other perpendicular to the mainstream direction. Three-dimensional flow exists, which is totally different to the well-known parabolic flow in straight pipes under laminar flow conditions. Therefore, a short fundamental introduction to biofluid mechanics is presented in this paper. A coronary artery model with different bypasses is shown as an example. The coronary artery is a prominent cardiac vessel often affected by the atherosclerosis process, which can lead to its full blockage. Blood flow is restored by the construction of a bypass performed by implanting part of the saphenous vein. This bypass is subjected to varying flow conditions during the various phases of pulsatile blood flow. For precise location of the regions associated with flow abnormalities, flow visualization through the complete bypass, covering the arterial and bypass sections, is required. This forms the objective of the present work: to visualize flow changes in bypass models of the right coronary artery prior to its bifurcation under pulsatile flow conditions.
CROSS-SECTIONAL AREA MEASUREMENT OF SOFT TISSUES IN VITRO: A NON-CONTACT LASER SCAN METHOD
Authors: LIU MEI JUN JOLENE , CHOU SIAW MENG , GOH KHENG LIM , TAN SOON HUAT
Published: September 2008

Measurements of cross-sectional areas (CSAs) of soft tissues such as tendons and ligaments allow for the evaluation of the biomechanical properties of the tissue. Underlying in vitro techniques are data reduction approaches for determining the average thickness of the tissue and the assumption of the geometry of the cross-section, i.e. circular or elliptical. However, tissue distortions, sagging, and concavities could affect the reliability of these techniques, since these features may not be accounted for adequately. To address some of the concerns faced by these techniques, a non-contact (non-destructive) laser scan technique has been developed. In this technique, a laser scans along the axis of the tissue, a coordinate measuring machine simultaneously locates the corresponding point on the tissue based on the detection of reflected (attenuated) intensity, and, finally, computerized image analysis reconstructs the morphology of the tissue. This technique was applied to patellar tendons (PTs) from New Zealand rabbits. The scanning time for each PT was less than 2 minutes. Reconstructed three-dimensional surface plots revealed microconcavities consistent with images seen under optical microscopy. CSAs of these PTs were determined for repeatability and precision; results from a conventional approach which estimated the corresponding CSAs based on the average thickness and the assumption of ellipsoidal cross-sectional geometry were also determined for the purpose of comparison. Based on the standard cuboid model, the error between the laser technique and the conventional approach was within 0.4%; the reproducibility of the laser technique was within 2%.
UNSTEADY RESPONSE OF BLOOD FLOW THROUGH A COUPLE OF IRREGULAR ARTERIAL CONSTRICTIONS TO BODY ACCELERATION
Authors: MUSTAPHA NORZIEHA , CHAKRAVARTY SANTABRATA , MANDAL PRASHANTA K. , AMIN NORSARAHAIDA
Published: September 2008

A two-dimensional (2D) nonlinear mathematical model to study the response of the pulsatile flow of blood through a couple of irregular stenoses influenced by externally imposed periodic body acceleration is developed. The model is 2D and axisymmetric with an outline of the stenosis obtained from the three-dimensional (3D) casting of a mildly stenosed artery. The combined influence of an asymmetric shape and surface irregularities of the constrictions is explored in a computational study of blood flow through arterial stenoses with 48% areal occlusion. The arterial wall is treated as an elastic (moving wall) cylindrical tube having a couple of stenoses in its lumen, while the streaming blood is considered to be Newtonian. Solutions of the time-dependent nonlinear Navier–Stokes equations in the cylindrical coordinate system are obtained using a finite difference method based on the nonuniform and nonstaggered grids. The finite difference approximation helps to estimate the effects of body acceleration on the doubly constricted flow phenomena through several graphical representations quantitatively in order to validate the applicability of the present, improved mathematical model.
PARTICIPATORY INNOVATION
Authors: BUUR JACOB , MATTHEWS BEN
Published: September 2008

An increasing number of corporations engage with users in co-innovation of products and services. But there are a number of competing perspectives on how best to integrate these understandings into existing corporate innovation development processes. This paper maps out three of the dominant approaches, compares them in terms of goals, methods and basic philosophy, and shows how they may beneficially enrich one another. We will present an industrial innovation case that has been instrumental to the development of what we have termed "Participatory Innovation". Based on this, we will list the challenges such an approach sets to innovation management, and discuss research directions of what we see as fundamental to the development of the field of user-driven innovation.
USER-CENTRIC INNOVATIONS IN NEW PRODUCT DEVELOPMENT — SYSTEMATIC IDENTIFICATION OF LEAD USERS HARNESSING INTERACTIVE AND COLLABORATIVE ONLINE-TOOLS
Authors: BILGRAM VOLKER , BREM ALEXANDER , VOIGT KAI-INGO
Published: September 2008

Corporate innovation management geared to long-term success calls for a strategy to grow innovations into a substantial competitive advantage. This, however, coincides with an enormous failure-rate at the market, especially in the field of breakthrough innovations. Hence, in recent times, companies are trying to alleviate the risk of lacking user-acceptance through opening their innovation processes to external actors, particularly customers. The method of integrating lead users is determined by the effective and systematic identification of leading-edge customers, which is considered to be a critical phase within this approach. With the arrival of Web 2.0 applications, there is a huge potential to improve these selection processes. Our research into online communities and weblogs scrutinised the search criteria in an online environment and revealed the following characteristics as crucial factors for the online identification of lead users: being ahead of a market trend, high expected benefits, user expertise and motivation, extreme user needs as well as opinion leadership and an online commitment.
A Study in Inspiration: Charles Henry Turner (1867–1923) and the Investigation of Insect Behavior
Authors: Abramson Charles I.
Published: September 2008

Charles Henry Turner was an African American scientist who, while eking out a living as a high school science teacher, made important advances in the study of insect learning and behavior. Contributions include the development of research methods, investigations of color vision and pattern vision in honey bees, and the first demonstration of Pavlovian conditioning in an insect. This review begins with a biography and continues with a summary of his major research accomplishments. Also included are quotations from his publications and from people who knew him. In addition, the question is raised as to why Turner did not receive an academic appointment, and similar data of racial disparity are presented on the small number of African American entomologists. It is suggested that the story of Turner can be used to increase interest in entomology, especially among African Americans.
Two-Particle Dispersion in Isotropic Turbulent Flows
Authors: Salazar Juan P.L.C. , Collins Lance R.
Published: September 2008

Two-particle dispersion is of central importance to a wide range of natural and industrial applications. It has been an active area of research since Richardson's (1926) seminal paper. This review emphasizes recent results from experiments, high-end direct numerical simulations, and modern theoretical discussions. Our approach is complementary to Sawford's (2001) , whose review focused primarily on stochastic models of pair dispersion. We begin by reviewing the theoretical foundations of relative dispersion, followed by experimental and numerical findings for the dissipation subrange and inertial subrange. We discuss the findings in the context of the relevant theory for each regime. We conclude by providing a critical analysis of our current understanding and by suggesting paths toward further progress that take full advantage of exciting developments in modern experimental methods and peta-scale supercomputing.
Role of HDAC2 in the Pathophysiology of COPD
Authors: Barnes Peter J.
Published: September 2008

Chronic obstructive pulmonary disease (COPD), characterized by progressive inflammation in the small airways and lung parenchyma, is mediated by the increased expression of multiple inflammatory genes. The increased expression of these genes is regulated by acetylation of core histones, whereas histone deacetylase 2 (HDAC2) suppresses inflammatory gene expression. In COPD, HDAC2 activity and expression are reduced in peripheral lung and in alveolar macrophages, resulting in amplification of the inflammatory response. Corticosteroid resistance in COPD occurs because corticosteroids use HDAC2 to switch off activated inflammatory genes. The reduction in HDAC2 appears to be secondary to the increased oxidative and nitrative stress in COPD lungs. Antioxidants and inhibitors of nitric oxide synthesis may therefore restore corticosteroid sensitivity in COPD, but this can also be achieved by low concentrations of theophylline and curcumin, which act as HDAC activators.
Electrogenic NBCe1 (SLC4A4), but not electroneutral NBCn1 (SLC4A7), cotransporter undergoes cholinergic-stimulated endocytosis in salivary ParC5 cells
Authors: Perry Clint , Quissell David O. , Reyland Mary E. , Grichtchenko Irina I.
Published: September 2008

Cholinergic agonists are major stimuli for fluid secretion in parotid acinar cells. Saliva bicarbonate is essential for maintaining oral health. Electrogenic and electroneutral Na+-HCO3− cotransporters (NBCe1 and NBCn1) are abundant in parotid glands. We previously reported that angiotensin regulates NBCe1 by endocytosis in Xenopus oocytes. Here, we studied cholinergic regulation of NBCe1 and NBCn1 membrane trafficking by confocal fluorescent microscopy and surface biotinylation in parotid epithelial cells. NBCe1 and NBCn1 colocalized with E-cadherin monoclonal antibody at the basolateral membrane (BLM) in polarized ParC5 cells. Inhibition of constitutive recycling with the carboxylic ionophore monensin or the calmodulin antagonist W-13 caused NBCe1 to accumulate in early endosomes with a parallel loss from the BLM, suggesting that NBCe1 is constitutively endocytosed. Carbachol and PMA likewise caused redistribution of NBCe1 from BLM to early endosomes. The PKC inhibitor, GF-109203X, blocked this redistribution, indicating a role for PKC. In contrast, BLM NBCn1 was not downregulated in parotid acinar cells treated with constitutive recycling inhibitors, cholinergic stimulators, or PMA. We likewise demonstrate striking differences in regulation of membrane trafficking of NBCe1 vs. NBCn1 in resting and stimulated cells. We speculate that endocytosis of NBCe1, which coincides with the transition to a steady-state phase of stimulated fluid secretion, could be a part of acinar cell adjustment to a continuous secretory response. Stable association of NBCn1 at the membrane may facilitate constitutive uptake of HCO3− across the BLM, thus supporting HCO3− luminal secretion and/or maintaining acid-base homeostasis in stimulated cells.
Regulation of cell proliferation by intermediate-conductance Ca2+-activated potassium and volume-sensitive chloride channels in mouse mesenchymal stem cells
Authors: Tao Rong , Lau Chu-Pak , Tse Hung-Fat , Li Gui-Rong
Published: September 2008

Bone marrow mesenchymal stem cells (MSCs) are a promising cell source for regenerative medicine; however, their cellular physiology is not fully understood. The present study aimed at exploring the potential roles of the two dominant functional ion channels, intermediate-conductance Ca2+-activated potassium (IKCa) and volume-sensitive chloride ( ICl.vol) channels, in regulating proliferation of mouse MSCs. We found that inhibition of IKCa with clotrimazole and ICl.vol with 5-nitro-1-(3-phenylpropylamino) benzoic acid (NPPB) reduced cell proliferation in a concentration-dependent manner. Knockdown of KCa3.1 or Clcn3 with specific short interference (si)RNAs significantly reduced IKCa or ICl.vol density and channel protein and produced a remarkable suppression of cell proliferation (by 24.4 ± 9.6% and 29.5 ± 7.2%, respectively, P < 0.05 vs. controls). Flow cytometry analysis showed that mouse MSCs retained at G0/G1 phase (control: 51.65 ± 3.43%) by inhibiting IKCa or ICl.vol using clotrimazole (2 μM: 64.45 ± 2.20%, P < 0.05) or NPPB (200 μM: 82.89 ± 2.49%, P < 0.05) or the specific siRNAs, meanwhile distribution of cells in S phase was decreased. Western blot analysis revealed a reduced expression of the cell cycle regulatory proteins cyclin D1 and cyclin E. Collectively, our results have demonstrated that IKCa and ICl.vol channels regulate cell cycle progression and proliferation of mouse MSCs by modulating cyclin D1 and cyclin E expression.
The use of BeWo cells as an in vitro model for placental iron transport
Authors: Heaton Sarah J. , Eady John J. , Parker Mary L. , Gotts Kathryn L. , Dainty Jack R. , Fairweather-Tait Susan J. , McArdle Harry J. , Srai Kaila S. , Elliott Ruan M.
Published: September 2008

BeWo cells are a placental cell line that has been widely used as an in vitro model for the placenta. The b30 subclone of these cells can be grown on permeable membranes in bicameral chambers to form confluent cell layers, enabling rates of both nutrient uptake into the cells from the apical surface and efflux from the basolateral membrane to be determined. The aim of this study was to evaluate structural and functional properties of confluent b30 BeWo cell layers grown in bicameral chambers, focusing on the potential application for studying receptor-mediated uptake and transport of transferrin (Tf)-bound iron (Fe-Tf). While it proved extremely difficult to establish and maintain an intact BeWo cell monolayer, it was possible to grow the cells to a confluent multilayer. Iron, applied as Fe-Tf, was rapidly transported across this cell layer; 9.3 ± 0.5% of the total dose was transported after 8 h, equivalent to 38.8 ± 2.1 pmol·cm−2·h−1. Transfer of Tf across the cell layer was much more limited; 2.4 ± 0.2% of the total dose was transported after 8 h, equivalent to 5.0 ± 0.4 pmol·cm−2·h−1. Compartmental modeling of these data suggested that iron was transported across the cell layer predominantly, if not exclusively, via a transcellular route, whereas Tf taken up into the cells was predominantly recycled back to the apical compartment. The results suggest that these cells are very efficient at transporting iron and, under carefully controlled conditions, can be a valuable tool for the study of iron transport in the placenta.
The monomeric G proteins AGS1 and Rhes selectively influence Gαi-dependent signaling to modulate N-type (CaV2.2) calcium channels
Authors: Thapliyal Ashish , Bannister Roger A. , Hanks Christopher , Adams Brett A.
Published: September 2008

Activator of G protein Signaling 1 (AGS1) and Ras homologue enriched in striatum (Rhes) define a new group of Ras-like monomeric G proteins whose signaling properties and physiological roles are just beginning to be understood. Previous results suggest that AGS1 and Rhes exhibit distinct preferences for heterotrimeric G proteins, with AGS1 selectively influencing Gαi and Rhes selectively influencing Gαs. Here, we demonstrate that AGS1 and Rhes trigger nearly identical modulation of N-type Ca2+ channels (CaV2.2) by selectively altering Gαi-dependent signaling. Whole-cell currents were recorded from HEK293 cells expressing CaV2.2 and Gαi- or Gαs-coupled receptors. AGS1 and Rhes reduced basal current densities and triggered tonic voltage-dependent (VD) inhibition of CaV2.2. Additionally, each protein attenuated agonist-initiated channel inhibition through Gαi-coupled receptors without reducing channel inhibition through a Gαs-coupled receptor. The above effects of AGS1 and Rhes were blocked by pertussis toxin (PTX) or by expression of a Gβγ-sequestering peptide (masGRK3ct). Transfection with HRas, KRas2, Rap1A-G12V, Rap2B, Rheb2, or Gem failed to duplicate the effects of AGS1 and Rhes on CaV2.2. Our data provide the first demonstration that AGS1 and Rhes exhibit similar if not identical signaling properties since both trigger tonic Gβγ signaling and both attenuate receptor-initiated signaling by the Gβγ subunits of PTX-sensitive G proteins. These results are consistent with the possibility that AGS1 and Rhes modulate Ca2+ influx through CaV2.2 channels under more physiological conditions and thereby influence Ca2+-dependent events such as neurosecretion.
Nitric oxide modulates the cardiovascular effects elicited by acetylcholine in the NTS of awake rats
Authors: da Silva Liana Gouveia , Dias Ana Carolina Rodrigues , Furlan Elaina , Colombari Eduardo
Published: September 2008

Microinjection of acetylcholine chloride (ACh) in the nucleus of the solitary tract (NTS) of awake rats caused a transient and dose-dependent hypotension and bradycardia. Because it is known that cardiovascular reflexes are affected by nitric oxide (NO) produced in the NTS, we investigated whether these ACh-induced responses depend on NO in the NTS. Responses to ACh (500 pmol in 100 nl) were strongly reduced by ipsilateral microinjection of the NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME; 10 nmol in 100 nl) in the NTS: mean arterial pressure (MAP) fell by 50 ± 5 mmHg before l-NAME to 9 ± 4 mmHg, 10 min after l-NAME, and HR fell by 100 ± 26 bpm before l-NAME to 20 ± 10 bpm, 10 min after l-NAME (both P < 0.05). Microinjection of the selective inhibitor of neuronal nitric oxide synthase (nNOS), 1-(2-trifluoromethylphenyl) imidazole (TRIM; 13.3 nmol in 100 nl), in the NTS also reduced responses to ACh: MAP fell from 42 ± 3 mmHg before TRIM to 27 ± 6 mmHg, 10 min after TRIM ( P < 0.05). TRIM also tended to reduce ACh-induced bradycardia, but this effect was not statistically significant. ACh-induced hypotension and bradycardia returned to control levels 30–45 min after NOS inhibition. Control injections with d-NAME and saline did not affect resting values or the response to ACh. In conclusion, injection of ACh into the NTS of conscious rats induces hypotension and bradycardia, and these effects may be mediated at least partly by NO produced in NTS neurons.
Rapid changes in glutamate levels in the posterior hypothalamus across sleep-wake states in freely behaving rats
Authors: John Joshi , Ramanathan Lalini , Siegel Jerome M.
Published: September 2008

The histamine-containing posterior hypothalamic region (PH-TMN) plays a key role in sleep-wake regulation. We investigated rapid changes in glutamate release in the PH-TMN across the sleep-wake cycle with a glutamate biosensor that allows the measurement of glutamate levels at 1- to 4-s resolution. In the PH-TMN, glutamate levels increased in active waking (AW) and rapid eye movement (REM) sleep compared with quiet waking and nonrapid eye movement (NREM) sleep. There was a rapid (0.6 ± 1.8 s) and progressive increase in glutamate levels at REM sleep onset. A reduction in glutamate levels consistently preceded the offset of REM sleep by 8 ± 3 s. Short-duration sleep deprivation resulted in a progressive increase in glutamate levels in the PH-TMN, perifornical-lateral hypothalamus (PF-LH), and cortex. We found that in the PF-LH, glutamate levels took a longer time to return to basal values compared with the time it took for glutamate levels to increase to peak values during AW onset. This is in contrast to other regions we studied in which the return to baseline values after AW was quicker than their rise with waking onset. In summary, we demonstrated an increase in glutamate levels in the PH-TMN with REM/AW onset and a drop in glutamate levels before the offset of REM. High temporal resolution measurement of glutamate levels reveals dynamic changes in release linked to the initiation and termination of REM sleep.
High glucose activates PKC-ζ and NADPH oxidase through autocrine TGF-β1 signaling in mesangial cells
Authors: Xia Ling , Wang Hong , Munk Snezana , Kwan Janice , Goldberg Howard J. , Fantus I. George , Whiteside Catharine I.
Published: September 2008

Conversion of normally quiescent mesangial cells into extracellular matrix-overproducing myofibroblasts in response to high ambient glucose and transforming growth factor (TGF)-β1 is central to the pathogenesis of diabetic nephropathy. Previously, we reported that mesangial cells respond to high glucose by generating reactive oxygen species (ROS) from NADPH oxidase dependent on protein kinase C (PKC) -ζ activation. We investigated the role of TGF-β1 in this action of high glucose on primary rat mesangial cells within 1–48 h. Both high glucose and exogenous TGF-β1 stimulated PKC-ζ kinase activity, as measured by an immune complex kinase assay and immunofluorescence confocal cellular imaging. In high glucose, Akt Ser473 phosphorylation appeared within 1 h and Smad2/3 nuclear translocation was prevented with neutralizing TGF-β1 antibodies. Neutralizing TGF-β1 antibodies, or a TGF-β receptor kinase inhibitor (LY364947), or a phosphatidylinositol 3,4,5-trisphosphate (PI3) kinase inhibitor (wortmannin), prevented PKC-ζ activation by high glucose. TGF-β1 also stimulated cellular membrane translocation of PKC-α, -β1, -δ, and -ε, similar to high glucose. High glucose and TGF-β1 enhanced ROS generation by mesangial cell NADPH oxidase, as detected by 2,7-dichlorofluorescein immunofluorescence. This response was abrogated by neutralizing TGF-β1 antibodies, LY364947, or a specific PKC-ζ pseudosubstrate peptide inhibitor. Expression of constitutively active PKC-ζ in normal glucose caused upregulation of p22phox, a likely mechanism of NADPH oxidase activation. We conclude that very early responses of mesangial cells to high glucose include autocrine TGF-β1 stimulation of PKC isozymes including PI3 kinase activation of PKC-ζ and consequent generation of ROS by NADPH oxidase.
p53 regulates renal expression of HIF-1α and pVHL under physiological conditions and after ischemia-reperfusion injury
Authors: Sutton Timothy A. , Wilkinson Jared , Mang Henry E. , Knipe Nicole L. , Plotkin Zoya , Hosein Maya , Zak Katelyn , Wittenborn Jeremy , Dagher Pierre C.
Published: September 2008

Ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) and is characterized by widespread tubular and microvascular damage. The tumor suppressor p53 is upregulated after IRI and contributes to renal injury in part by promoting apoptosis. Acute, short-term inhibition of p53 with pifithrin-α conveys significant protection after IRI. The hypoxia-inducible factor-1 (HIF-1) pathway is also activated after IRI and has opposing effects to those promoted by p53. The balance between the HIF-1 and p53 responses can determine the outcome of IRI. In this manuscript, we investigate whether p53 regulates the HIF-1 pathway in a rodent model of IRI. HIF-1α is principally expressed in the collecting tubules (CT) and thick ascending limbs (TAL) under physiological conditions. However, inhibition of p53 with pifithrin-α increases the faint expression of HIF-1α in proximal tubules (PT) under physiological conditions. Twenty-four hours after IRI, HIF-1α expression is decreased in both CT and TAL. HIF-1α expression in the PT is not significantly altered after IRI. Acute inhibition of p53 significantly increases HIF-1α expression in the PT after IRI. Additionally, pifithrin-α prevents the IRI-induced decrease in HIF-1α in the CT and TAL. Parallel changes are observed in the HIF-1α transcriptive target, carbonic anhydrase-9. Finally, inhibition of p53 prevents the dramatic changes in Von Hippel-Lindau protein morphology and expression after IRI. We conclude that activation of p53 after IRI mitigates the concomitant activation of the protective HIF-1 pathway. Modulating the interactions between the p53 and HIF-1 pathway can provide novel options in the treatment of AKI.