bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmission of single-flux-quantum pulse between superconductor chips
Authors: Hashimoto Yoshihito , Yorozu Shinichi , Miyazaki Toshiyuki
Published: February 2005

Single-flux-quantum (SFQ) pulse transmission between superconductor chips mounted on a passive microstrip carrier is reported. In contrast to the earlier work based on a double-flux-quantum (DFQ) driver, we used an SFQ driver; that is, the simplest driver. To deal with transmission loss at solder-bump bonds, we improved the receiver’s sensitivity by reducing its critical current, and optimized the SFQ driver to have as large an output amplitude as possible with a sufficient bias margin. Chip-to-chip transmission on a passive microstrip carrier with 50μm solder-bump bonds up to 60Gbps has been achieved at a junction critical current density of 2.5KA∕cm2.
Shallow electronic states induced by prismatic stacking faults in AlN and GaN
Authors: Northrup J. E.
Published: February 2005

Wurtzite materials such as AlN and GaN can exhibit prismatic stacking faults on the (1-210) plane with a stacking fault displacement vector RD=1∕2[10-11]. These faults thread in the [0001] direction and may arise in growth on the (0001) plane from the merging of independently nucleated islands. Merging islands that have different stacking sequences in the [0001] direction, for example ABAB… vs ACAC…, give rise to the faults. The formation energy of such a stacking fault in AlN is determined using first-principles total energy calculations to be 79meV∕Å2. The perturbation caused by the highly strained four-membered rings of bonds along the boundary gives rise to shallow stacking fault states 0.1eV above the valence band maximum and 0.1eV below the conduction band minimum. These results are compared to those obtained for GaN.
Electron-hopping modes in NiMn2O4+δ materials
Authors: Schmidt R. , Basu A. , Brinkman A. W. , Klusek Z. , Datta P. K.
Published: February 2005

The resistance versus temperature (R–T) characteristics of NiMn2O4+δ thermistors have been analyzed. In the literature, electron transport in manganate spinels is commonly described by a small-polaron model for nearest neighbor hopping, but variable range hopping (VRH) has not been considered so far. In this study differentiated R–T data were analyzed, allowing a clear distinction between different modes of hopping. In pressed pellets and thick screen printed films conduction was well described by a VRH model for a parabolic density of states, which was confirmed by scanning tunneling spectroscopy.
Plankton succession and assemblage structure in two neighbouring littoral ecosystems in the north-west Mediterranean Sea
Authors: Jamet J.-L. , Jean N. , Bogé G. , Richard S. , Jamet D.
Published: February 2005

We studied seasonal variations in bacterial abundance and succession in phyto- and zooplankton assemblages (particularly small taxa) in two neighbouring shallow bays (near Toulon, Mediterranean Sea, France): Little Bay (polluted, eutrophic), and Niel Bay (less polluted, oligotrophic). In Little Bay, bacteria developed in northern spring and phytoplankton (Dinophyceae > 20 µm) in late northern winter–early spring. Zooplankton levels peaked at the end of northern spring and in autumn; this community was dominated by Oithona nana. In Niel Bay, bacterial levels peaked during northern spring and autumn. Phytoplankton (Dinophyceae, Bacillariophyceae) abundance was low and only peaked in June. Zooplankton levels peaked in northern mid-summer. Little Bay was influenced more by the land and by human activities than by the sea. Seasonal factors (e.g. water temperature) and sudden influences (e.g. rain and, indirectly, Mistral wind) may have modified the succession of the plankton communities in this bay. Successions did not follow Margalef’s model and the classical scheme for zooplankton. Conversely, Niel Bay functioning and plankton assemblages were most influenced by the physical environment of the sea than by the land or by human activities. Successions were closely related to the classical scheme of the Mediterranean Sea.
The partitioning of zinc, manganese, cadmium and selenium within copepods in oceanic waters east of New Zealand
Authors: Mackie Douglas S. , Hunter Keith A.
Published: February 2005

The partitioning of Zn, Mn, Cd and Se within mesozooplankton, mainly calanoid copepods, is reported for two geographically close but biogeochemically distinct water masses (subtropical (ST) and subantarctic (SA) waters) during a transect east of New Zealand in austral spring 1997. Particular attention was paid to avoiding sample contamination during collection, handling and chemical analysis by using trace metal clean techniques. Mesozooplankton underwent a sequential chemical leaching scheme to determine the degree and type of elemental associations within labile and refractory tissues. All four elements showed a positive correlation with the phosphorus content of each fraction indicating a consistent relationship to the amount of tissue dissolved in each fraction. Ratios of Cd : P and Zn : P in samples from SA waters were over twice those in ST waters. However, no significant differences were found between Mn : P and Se : P ratios for samples from the two water masses.
Reproductive biology, size and age compositions and growth of the batoid Urolophus paucimaculatus, including comparisons with other species of the Urolophidae
Authors: White William T. , Potter Ian C.
Published: February 2005

The biology of Urolophus paucimaculatus in south-western Australian waters has been examined and compared with that of the co-occurring Urolophus lobatus, Trygonoptera personata and Trygonoptera mucosa. These four species represent the only two genera of the Urolophidae. Urolophus paucimaculatus conceives in early/mid-summer and gives birth in late spring/early summer, closely paralleling the situation with U. lobatus. Although Trygonoptera species likewise have a 10–12-month gestation period, they conceive and give birth in late autumn to mid-winter. The marked intergeneric differences in birth time help account for pronounced intergeneric differences in the diets of their newly born young. By birth, Urolophus paucimaculatus attains ~50% of its asymptotic size. The relatively large mean disc width of the four urolophids at birth, i.e. 105–128 mm, accounts for the small litters of these species (1–2 young per litter). Size at maturity and maximal size and age of each species are greater for females than males and are greater for Trygonoptera than Urolophus species. The growth of U. paucimaculatus and the other urolophids throughout pre- and postnatal life can be described by a single smooth growth curve. The maintenance of a constant pattern of growth from conception is remarkable because the diet and behaviour of these elasmobranchs changes radically at parturition.
Modeling variation in tumors
in vivo
Authors: Stringer James R. , Larson Jon S. , Fischer Jared M. , Medvedovic Mario , Hersh Megan N. , Boivin Gregory P. , Stringer Saundra L.
Published: February 2005

Transgenic mice that allow mutant cells to be visualized
in situ
were used to study variation in tumors. These mice carry the G11 placental alkaline phosphatase (PLAP) transgene, a mutant allele rendered incapable of producing its enzyme product by a frameshift caused by insertion of a tract of G:C base pairs in a coding region. Spontaneous deletion of one G:C base pair from this tract restores gene function, and cells with PLAP activity can be detected histochemically. To study tumors, the G11 PLAP transgene was introduced into the polyoma virus middle T antigen mammary tumor model. Tumors in these mice exhibited up to 300 times more PLAP
+
cells than normal tissues. PLAP
+
cells were located throughout each tumor. Many of the PLAP
+
cells were singlets, but clusters also were common, with one cluster containing >30,000 cells. Comparison of these data to simulations produced by computer models suggested that multiple factors were involved in generating mutant cells in tumors. Although genetic instability appeared to have occurred in most tumors, large clusters were much more common than expected based on instability alone.
Disturbed Ca2+signaling and apoptosis of medium spiny neurons in Huntington's disease
Authors: Tang Tie-Shan , Slow Elizabeth , Lupu Vitalie , Stavrovskaya Irina G. , Sugimori Mutsuyuki , Llinás Rodolfo , Kristal Bruce S. , Hayden Michael R. , Bezprozvanny Ilya
Published: February 2005

Huntington's disease (HD) is caused by polyglutamine expansion (exp) in huntingtin. Here, we used a yeast artificial chromosome (YAC) transgenic mouse model of HD to investigate the connection between disturbed calcium (Ca2+) signaling and apoptosis of HD medium spiny neurons (MSN). Repetitive application of glutamate elevates cytosolic Ca2+levels in MSN from the YAC128 mouse but not in MSN from the wild-type or control YAC18 mouse. Application of glutamate results in apoptosis of YAC128 MSN but not wild-type or YAC18 MSN. Analysis of glutamate-induced apoptosis of the YAC128 MSN revealed that (i) actions of glutamate are mediated by mGluR1/5 and NR2B glutamate receptors; (ii) membrane-permeable inositol 1,4,5-trisphosphate receptor blockers 2-APB and Enoxaparin (Lovenox) are neuroprotective; (iii) apoptosis involves the intrinsic pathway mediated by release of mitochondrial cytochromecand activation of caspases 9 and 3; (iv) apoptosis requires mitochondrial Ca2+overload and can be prevented by the mitochondrial Ca2+uniporter blocker Ruthenium 360; and (v) apoptosis involves opening of mitochondrial permeability transition pore (MPTP) and can be prevented by MPTP blockers such as bongkrekic acid, Nortriptyline, Desipramine, Trifluoperazine, and Maprotiline. These findings describe a pathway directly linking disturbed Ca2+signaling and degeneration of MSN in the caudate nucleus in HD. These findings also suggest that Ca2+and MPTP blockers may have a therapeutic potential for treatment of HD.
Two distinctive pathways for recruitment of naïve and primed IgM+B cells to the gut lamina propria
Authors: Suzuki Keiichiro , Meek Bob , Doi Yasuko , Honjo Tasuku , Fagarasan Sidonia
Published: February 2005

Intestinal IgA+B cells are generated from IgM+B cells byin situclass switching in two separate gut microenvironments: organized follicular structures and lamina propria (LP). However, the origin of IgM+B cells in the gut LP is unknown. Transfer experiments to reconstitute IgM+B cells and IgA plasma cells in LP ofaly/alymice, which are defective in all organized follicular structures because of an NF-κB-inducing kinase (NIK) mutation, revealed that naïve B cells can directly migrate to the LP. This migration requires NIK-dependent activation of gut stromal cells. By contrast, the entry of gut-primed IgM+B cells to the LP is independent of stromal cells with functional NIK. Our results indicate that naïve B cells directly migrate to the LP by a distinct pathway from gut-primed B cells.
Clinical Pathology Approaches to Hepatic Injury
Authors: Solter Philip F.
Published: February 2005

Testing the blood for evidence of hepatic damage and dysfunction frequently involves measuring several blood constituents simultaneously to screen for disease. While useful, this approach occasionally leads to apparent disparities between the blood test results, and the results of other diagnostic tests such as histology. In part, these perceived discrepancies may stem from a lack of appreciation for tissue, cellular, and molecular factors that affect the appearance of hepatic disease biomarkers in the blood. Further confusing the matter is that in some instances the mechanisms responsible for the appearance of diagnostic compounds in blood are only partially understood. Many of the known factors that affect hepatic biomarkers are similar to those affecting other tissue markers, while others are unique to the liver, such as those involved with cholestasis. Disease conditions can also cause misleading results by affecting tissue concentrations of test compounds, hepatic mass, and the clearance rate of compounds from the blood. Knowledge of the factors affecting the blood concentrations of biomarkers, as well as investigations into the mechanisms behind changes to hepatic biomarker concentrations, may allow for a better interpretation of blood test results and fewer inconsistencies between diagnostic results.
Molecular Mechanisms of Hepatocarcinogenesis in Transgenic Mouse Models of Liver Cancer
Authors: Calvisi Diego F. , Thorgeirsson Snorri S.
Published: February 2005

Overexpression of c-myc and transforming growth factor-alpha (TGF-α) has been frequently observed in human hepatocellular carcinoma (HCC), suggesting a pivotal role played by these protooncogenes in liver oncogenesis. In order to investigate the molecular events underlying human hepatic malignant transformation, we have generated c-myc and c-myc/TGF-α transgenic mice that are prone to liver cancer. These transgenic mice develop HCCs with different incidence, kinetics and histopathological features. Indeed, co-expression of c-myc and TGF-α transgenes results in a dramatic synergistic effect on liver tumor development when compared with respective single transgenic lines, including a shorter latency period and a more aggressive phenotype. The more malignant histopathological features characteristic of c-myc/TGF-α HCCs are the result of the increased proliferation and reduced apoptosis in this model of liver cancer when compared with single parental lines. Accordingly, c-myc and c-myc/TGF-α transgenic mice display a different molecular pathogenesis of HCC. Importantly, the genetic and molecular mechanisms that are involved in c-myc and c-myc/TGF-α liver cancer development are major oncogenic events in human hepatocarcinogenesis, indicating that these mouse models represent a useful tool to dissect and elucidate the molecular basis of human HCC.
Overview of the Molecular Biology of Hepatocellular Neoplasms and Hepatoblastomas of the Mouse Liver
Authors: Kim Yongbaek , Sills Robert C. , Houle Chris D.
Published: February 2005

The molecular pathogenesis of chemically induced hepatocellular neoplasms and hepatoblastomas in the B6C3F1 mouse is unclear but may involve alterations in the β-catenin/Wnt signaling pathway as was recently described for human liver neoplasms. The objectives of this research were to characterize the mutation frequency and spectrum of β-catenin mutations and the intracellular localization of β-catenin protein accumulation in chemically induced hepatoblastomas and hepatocellular neoplasms. In the majority of the hepatoblastomas examined by immunohistochemical methods, both nuclear and cytoplasmic localization of β-catenin protein were detected, whereas in hepatocellular adenomas and carcinomas and normal liver only membrane staining was observed. Genomic DNA was isolated from paraffin sections of each liver tumor. β-catenin exon 2 (corresponds to exon 3 in humans) genetic alterations were identified in the majority of hepatoblastomas from exposed mice. Deletion mutations were identified more frequently than point mutations in hepatoblastomas. Hepatocellular adenomas and carcinomas from treated mice had mutations in exon 2 of the β-catenin gene which ranged from 32–43%, while 10% β-catenin mutations were detected in spontaneous neoplasms. By immunohistochemical methods cyclin D1 was observed in most nuclei of hepatoblastomas and strong expression of cyclin D1 was confirmed by Western analysis regardless of treatment. The cumulative data suggests that β-catenin mutations with upregulation of the β-catenin protein and Wnt signaling most likely increased cyclin D1 expression. Cyclin D1 may provide an advantage during tumor progression of hepatocellular neoplasms and hepatoblastomas. The review will also focus on other genes which are important in mouse and human liver tumors.
The Hepatic Transcriptome as a Window on Whole-Body Physiology and Pathophysiology
Authors: Morgan Kevin T. , Jayyosi Zaid , Hower Moira A. , Pino Michael V. , Connolly Timothy M. , Kotlenga Katja , Lin Jieyi , Wang Min , Schmidts Hans-Ludwig , Bonnefoi Marc S. , Elston Timothy C. , Boorman Gary A.
Published: February 2005

Transcriptomics can be a valuable aid to pathologists. The information derived from microarray studies may soon include the entire transcriptomes of most cell types, tissues and organs for the major species used for toxicology and human disease risk assessment. Gene expression changes observed in such studies relate to every aspect of normal physiology and pathophysiology. When interpreting such data, one is forced to look “far from the lamp post,” and in so doing, face one’s ignorance of many areas of biology. The central role of the liver in toxicology, as well as in many aspects of whole-body physiology, makes the hepatic transcriptome an excellent place to start your studies. This article provides data that reveals the effects of fasting and circadian rhythm on the rat hepatic transcriptome, both of which need to be kept in mind when interpreting large-scale gene expression in the liver. Once you become comfortable with evaluating mRNA expression profiles and learn to correlate these data with your clinical and morphological observations, you may wonder why you did not start your studies of transcriptomics sooner. Additional study data can be viewed at the journal website at < www.toxpath.org >. Two data files are provided in Excel format, which contain the control animal data from each of the studies referred to in the text, including normalized signal intensity data for each animal (n = 5) in the 6-hour, 24-hour, and 5-day time points. These files are briefly described in the associated ‘Readme’ file, and the complete list of GenBank numbers and Affymetrix IDs are provided in a separate txt file. These files are available at http://taylorandfrancis.metapress.com/openurl.asp?genre=journal&issn=0192-6233 . Click on the issue link for 33(1), then select this article. A download option appears at the bottom of this abstract. In order to access the full article online, you must either have an individual subscription or a member subscription accessed through < www.toxpath.org >.
Transcriptional Profiling of the Left and Median Liver Lobes of Male F344/N Rats Following Exposure to Acetaminophen
Authors: Richard Irwin D. , Parker Joel S. , Lobenhofer Edward K. , Burka Leo T. , Blackshear Pamela E. , Vallant Molly K. , Lebetkin Edward H. , Gerken Diane F. , Boorman Gary A.
Published: February 2005

The liver is a common organ for transcriptional profiling because of its role in xenobiotic metabolism and because hepatotoxicity is a common response to chemical exposure. To explore the impact that sampling different lobes may have on transcriptional profiling experiments we have examined and compared gene expression profiles of the left and median lobes of livers from male F344 rats exposed to toxic and nontoxic doses of acetaminophen. Transcript profiling using micorarrays revealed clear differences in the response of the left and median liver lobes of F344 rats to acetaminophen exposure both at low doses as well as doses that caused hepatotoxicity. Differences were found in the total number of differentially expressed genes in the left and median lobes, the number and identity of genes that were differentially expressed uniquely only in the left or median lobe, and in the patterns of gene expression. While it is not possible to generalize these results to compounds other than acetaminophen or other strains of rat, these results highlight the potential impact of sampling differences on the interpretation of gene expression profiles in the liver.
Mechanistic Classification of Liver Injury
Authors: Cullen John M.
Published: February 2005

Toxic injury occurs in the liver more often than any other organ. This can be attributed to the fact that virtually all ingested substances that are absorbed are first presented to the liver and that the liver is responsible for the metabolism and elimination of many substances. Drug-induced liver injury has become a serious health problem in contemporary society. Moreover, liver toxicity is a significant impediment to development of new pharmaceuticals. A classification of liver injury is presented as a means to better understand the spectrum of known mechanisms of liver injury and to assist in discovering novel pathways of toxic liver injury.
Using Laser Scanning Cytometry to Measure PPAR-Mediated Peroxisome Proliferation and β Oxidation
Authors: Pruimboom-Brees Ingrid M. , Brees Dominique J. J. E. , Shen Amy C. , Keener Mary , Francone Omar , Amacher David E. , Loy James K. , Kerlin Roy L.
Published: February 2005

Laser scanning cytometry (LSC) is a new technology that combines the properties and advantages of flow cytometry (FC) and immunohistochemistry (IHC), thus providing qualitative and quantitative information on protein expression with the additional perspective provided by cell and tissue localization. Formalin-fixed, paraffin embedded liver sections from rats exposed to a Peroxisome Proliferator Activated Receptor (PPAR) agonist were stained with antibodies against peroxisomal targeting signal-1 (PTS-1) (a highly conserved tripeptide contained within all peroxisomal enzymes), Acyl CoA oxidase (AOX) (the rate limiting enzyme of peroxisomal β oxidation), and catalase (an inducible peroxisomal antioxidant enzyme) to evaluate peroxisomal β oxidation, oxidative stress, and peroxisome proliferation. The LSC showed increased AOX, catalase, and PTS-1 expression in centrilobular hepatocytes that correlated favorably with the microscopic observation of centrilobular hepatocellular hypertrophy and with the palmitoyl CoA biochemical assay for peroxisomal β oxidation, and provided additional morphologic information about peroxisome proliferation and tissue patterns of activation. Therefore, the LSC provides qualitative and quantitative evaluation of peroxisome activity with similar sensitivity but higher throughput than the traditional biochemical methods. The additional benefits of the LSC include the direct correlation between histopathologic observations and peroxisomal alterations and the potential utilization of archived formalin-fixed tissues from a variety of organs and species.
New Insights into Functional Aspects of Liver Morphology
Authors: Malarkey David E. , Johnson Kennita , Ryan Linda , Boorman Gary , Maronpot Robert R.
Published: February 2005

The liver is structurally and functionally complex and has been considered second only to brain in its complexity. Many mysteries still exist in this heterogeneous tissue whose functional unit of the lobule has continued to stump morphologists for over 300 years. The primary lobule, proposed by Matsumoto in 1979, has been gaining acceptance as the functional unit of the liver over other conceptual views because it’s based on vessel architecture and includes the classic lobule as a secondary feature. Although hepatocytes comprise almost 80% of the liver, there are at least another dozen cell types, many of which provide “cross-talk” and play important functional roles in the normal and diseased liver. The distribution and functional roles of all cells in the liver must be carefully considered in both the analysis and interpretation of research data, particularly data in the area of genomics and “phenotypic anchoring” of gene expression results. Discoveries regarding the functional heterogeneity of the various liver cell types, including hepatocytes, hepatic stellate cells, sinusoidal endothelia, and Kupffer cells, are providing new insights into our understanding of the development, prevention and treatment of liver disease. For example, functional differences along zonal patterns (centrilobular or periportal) have been demonstrated for sinusoidal endothelium, Kupffer cells, and hepatocytes and can explain the gradients and manifestations of disease observed within lobules. Intralobular gradients of bile uptake, glycogen depletion, glutamine synthetase, and carboxylesterase by hepatocytes; widened fenestrations in centrilobular sinusoidal lining cells; and differences in the components of centrilobular extracellular matrix or function of Kupffer cells have been demonstrated. Awareness of the complexities and heterogeneity of the liver will add to a greater understanding of liver function and disease processes that lead to toxicity, cancer, and other diseases.
Idiosyncratic Liver Injury: Challenges and Approaches
Authors: Watkins Paul B.
Published: February 2005

Clinical presentations of drug-induced liver injury (DILI) cover essentially the entire spectrum of known liver diseases. However, in the last 8 years the form of liver injury that has most frequently resulted in labeling restrictions is idiosyncratic hepatocellular injury leading to acute liver failure. This rare form of DILI has a characteristic clinical presentation that includes an acute onset after uneventful treatment with drug for weeks to months. Serum alanine aminotransferase rises to very high levels and the appearance of jaundice indicates a high mortality even if the therapy is discontinued. Drugs that can cause this type of injury almost always are associated with frequent (2–15% of all treated patients) and minor serum aminotransferase elevations. These elevations are believed to reflect true liver injury, but often reverse even if drug therapy is continued. The basis for this “adaptation” is not known, as is why some patients do not adapt and develop progressive liver injury. Understanding how drugs cause severe idiosyncratic hepatocellular toxicity has been frustrated by the lack of good preclinical models. Indeed, because these events occur so rarely, the vast majority of humans are not good models. Studies of genomic DNA from affected individuals should provide important insight but not the complete answer because environmental factors almost certainly contribute to individual susceptibility. The most fruitful approach may therefore lie in focused and well-controlled phenotype/genotype studies of the rare patients who have survived this type of injury. The National Institute of Diabetes and Digestive and Kidney Diseases of The National Institutes of Health has recently sponsored a cooperative agreement (UO1) to create a Drug Induced Liver Injury Network (DILIN). DILIN consists of University of Michigan, Indiana University, University of Connecticut, University of California, San Francisco, University of North Carolina, and Duke University. This network should provide heretofore missing resources required to address the problem.
Microarray Data Analysis of Mouse Neoplasia
Authors: Malarkey David E. , Parker Joel S. , Turman Coral A. , Scott Allyson M. , Paules Richard S. , Collins Jennifer , Maronpot Robert R.
Published: February 2005

Microarray gene expression analysis offers great promise to help us understand the molecular events of experimental carcinogenesis, but have such promises been fulfilled? Studies of gene expression profiles of rodent are being published and demonstrate that yes, indeed, gene array data is furthering our understanding of tumor biology. Recent studies have identified differentially expressed genes in rodent mammary, colon, lung, and liver tumors. Although relatively few genes on the rodent arrays have been fully characterized, information has been generated to better identify signatures of histologic type and grade, understand invasion and metastasis, identify candidate biomarkers of early development, identify gene networks in carcinogenesis, understand responses to therapy, and decifer overlap with molecular events in human cancers. Data from mouse lung, mammary gland, and liver tumor studies are reviewed as examples of how to approach and interpret gene array data. Methods of gene array data analysis were also applied for discovery of genes involved in the regression of mouse liver tumors induced by chlordane, a nongenotoxic murine hepatocarcinogen. Promises are beginning to be fulfilled and it is clear that pathologists and toxicologists, in collaboration with molecular biologists, bioinformatists, and other scientists are making great strides in the design, analysis, and interpretation of microarray data for cancer studies.
Classification of Proliferative Hepatocellular Lesions in Harlan Sprague–Dawley Rats Chronically Exposed to Dioxin-Like Compounds
Authors: Hailey James R. , Walker Nigel J. , Sells Donald M. , Brix Amy E. , Jokinen Michael P. , Nyska Abraham
Published: February 2005

Over the years, the most appropriate classification scheme for nodular proliferative lesions of the hepatocyte has been heavily debated. In the most recent guidelines there appears to be a consensus for classifying these lesions as hepatocellular adenoma, hepatocellular carcinoma, or regenerative hyperplasia. Also, large foci of cellular alteration may appear somewhat nodular. Some nodular hepatocellular lesions from a group of 7 studies of dioxin and dioxin-like compounds conducted by the National Toxicology Program did not readily fit into these categories. Some of these lesions had morphologic features consistent with hyperplasia. However, there was not sufficient morphological or biological evidence to conclude that the entire response was regenerative. In other instances, these lesions had some features resembling adenoma, but contained a prominent component of biliary epithelium and/or oval cells. This component does not appear to be well described in the literature, and while its presence suggested a nodule to be nonneoplastic, this is inconclusive. This paper describes the morphology of these lesions, as well as the diagnostic approach taken in this series of studies.
Character complexity and redundancy in writing systems over human history
Authors: Changizi Mark A. , Shimojo Shinsuke
Published: February 2005

A writing system is a visual notation system wherein a repertoire of marks, or strokes, is used to build a repertoire of characters. Are there any commonalities across writing systems concerning the rules governing how strokes combine into characters; commonalities that might help us identify selection pressures on the development of written language? In an effort to answer this question we examined how strokes combine to make characters in more than 100 writing systems over human history, ranging from about 10 to 200 characters, and including numerals, abjads, abugidas, alphabets and syllabaries from five major taxa: Ancient Near–Eastern, European, Middle Eastern, South Asian, Southeast Asian. We discovered underlying similarities in two fundamental respects.

(i) The number of strokes per characters is approximately three, independent of the number of characters in the writing system; numeral systems are the exception, having on average only two strokes per character.

(ii) Characters are
ca
. 50% redundant, independent of writing system size; intuitively, this means that a character's identity can be determined even when half of its strokes are removed.

Because writing systems are under selective pressure to have characters that are easy for the visual system to recognize and for the motor system to write, these fundamental commonalities may be a fingerprint of mechanisms underlying the visuo–motor system.
Tasting the difference: do multiple defence chemicals interact in Müllerian mimicry?
Authors: Skelhorn John , Rowe Candy
Published: February 2005

Müllerian mimicry, where two unpalatable species share a warning pattern, is classically believed to be a form of mutualism, where the species involved share the cost of predator education. The evolutionary dynamics of Müllerian mimicry have recently become a controversial subject, after mathematical models have shown that if minor alterations are made to assumptions about the way in which predators learn and forget about unpalatable prey, this textbook case of mutualism may not be mutualistic at all. An underlying assumption of these models is that Müllerian mimics possess the same defence chemical. However, some Müllerian mimics are known to possess different defence chemicals. Using domestic chicks as predators and coloured crumbs flavoured with either the same or different unpalatable chemicals as prey, we provide evidence that two defence chemicals can interact to enhance predator learning and memory. This indicates that Müllerian mimics that possess different defence chemicals are better protected than those that share a single defence chemical. These data provide insight into how multiple defence chemicals are perceived by birds, and how they influence the way birds learn and remember warningly coloured prey. They highlight the importance of considering how different toxins in mimicry rings can interact in the evolution and maintenance of Müllerian mimicry and could help to explain the remarkable variation in chemical defences found within and between species.
On estimating the number of species from the discovery record
Authors: Solow Andrew R. , Smith Woollcott K.
Published: February 2005

A common approach to estimating the number of species in a taxonomic or other group is to extrapolate the temporal pattern of historical species discoveries or descriptions. A formal statistical approach to this problem is described. This approach involves fitting an explicit model of the discovery record by maximum like lihood and using the fitted model to estimate the number of undiscovered species. The approach is applied to a description record of large marine animals covering the period 1828–1996. The estimated number of undiscovered species in this group is around 10 with an upper 0.95 confidence bound of around 16.
Helpers in a cooperatively breeding cichlid stay and pay or disperse and breed, depending on ecological constraints
Authors: Bergmüller Ralph , Heg Dik , Taborsky Michael
Published: February 2005

The theory of family–group dynamics predicts that group structure, helping behaviour and social interactions among group members should vary with the opportunities of subordinates to breed independently. We investigated experimentally whether unrelated mature helpers in the cooperatively breeding cichlid
Neolamprologus pulcher
reduce costly social and cooperative behaviour and choose to disperse and breed independently when offered vacant breeding sites. As predicted by the ecological constraints hypothesis, when breeding substrate was available, (i) helpers spent more time in dispersal areas and it was mainly large helpers that left the group to breed independently; (ii) all helpers invested less in costly submissive behaviours towards other group members and large helpers reduced help, supporting the ‘pay–to–stay’ hypothesis; and (iii) large helpers, particularly those that dispersed and bred, increased more in body mass in the treatment than those without breeding options, suggesting status–dependent strategic growth of helpers. We conclude that helpers of
N. pulcher
decide whether to stay and pay or disperse and breed in response to constraints on independent breeding.
Analysis of potential flow field in a two‐dimensional duct
Authors: Shin Jung‐Chul
Published: February 2005

The potential flow field for the transitional region in a constant radius, two‐dimensional duct was studied. The potential velocity and pressure profiles in various duct geometries with different turning angles and duct heights were investigated. A generalized solution of potential flow in a transitional bend was obtained.
Cooling analysis eliminates fan, reducing weight and power draw
Authors: Nickell Thomas
Published: February 2005

Describes how engineers from Lockheed Martin, USA, reduced the weight and power draw of an oscillator in an aircraft electrical assembly by using computational fluid dynamics to optimize radiative and natural convective cooling, thereby eliminating the need for a fan within the assembly.
Composite design software reduces engineering time on Eurofighter parts
Authors: Williams Tony , Birchall Brian , Rishton Julian
Published: February 2005

Composite design software is helping engineers from British Aerospace to reduce significantly engineering time on composite parts for the Eurofighter 2000 aircraft. FiberSIM’ simulation software from Composite Design Technologies (CDT), Waltham, Massachusetts, allows manufacturing engineers to define the composite lay‐up on a computer, eliminating the old, industry‐wide trial and error process that was used to lay composite plies onto a complex surface. The new technology ensures that manufacturing reflects the design intent and reduces weight by avoiding unnecessary patches. British Aerospace also expects additional production time savings by using the software to program laser projection equipment.
Total Quality: Teamsmanship over Leadership
Authors: Schonberger Richard J.
Published: February 2005

Total quality management sharply modifies management itself. As teams
and teamwork take root, leadership idolatry fades in importance.
Teamsmanship requires breaking vertical and horizontal barriers that
stand in the way of quick, high‐quality customer service. Management
tools helpful in barrier‐busting include team‐building, cross‐training,
job rotation, cross‐careering, project teams, and re‐engineering. While
these tools are in wide use, companies often misapply or weakly apply
them. Examples are given of how some companies use these tools in ways
that effectively enhance teamsmanship. Teamsmanship also feeds on
information, which must be widely shared. In most Western cultures,
however, people tend jealously to guard their own knowledge and
personally acquired information. Organizations must employ systematic
devices that promote information sharing. Among the better known such
devices are benchmarking and quality function deployment. Also useful,
but less familiar, are common files and the “star system”. As applied by a
small number of organizations, these techniques can become effective
tools of teamsmanship.
The Urban Sensorium: Space, Ideology and the Aestheticization of Politics
Authors: Goonewardena Kanishka
Published: February 2005

This essay outlines a theoretical framework for investigating the links between the production of urban space (Lefebvre) and the production of ideology (Althusser) and hegemony (Gramsci) by proposing the concept of “the urban sensorium”. With a view to the aesthetics of urban experience and everyday life, this concept aligns Fredric Jameson's “postmodern” adaptation of city planner Kevin Lynch's research on “cognitive mapping” with Walter Benjamin's insights on “aestheticizing politics” in order to ask: how does urban space mediate ideology and produce hegemony while aestheticizing politics? In so doing, the spotlight falls on a conceptual constellation including four key theoretical terms: “ideology”, “aesthetics”, “mediation” and “totality”. While working through them, the essay argues that Jameson's outstanding contribution to a spatialized understanding of “postmodernism” lies above all in his Marxist (Lukácsian, Althusserian and Sartrean) theorization of mediation and totality; whereas radical students of the city can find the richest dialectical elaboration of these two concepts with special attention to space and urbanism in the oeuvre of Henri Lefebvre, especially in the recently translated The Urban Revolution.
The Terrible Geographicalness of Terrorism: Reflections of a Hazards Geographer
Authors: Mustafa Daanish
Published: February 2005

Oppositional engagement with the phenomenon of terrorism by geographers could bring much needed scholarly clarity and balance to the militaristic dominant discourse on terrorism. The hazards subfield within the discipline of geography is germane to research on terrorism, as hazards geographers have been deeply concerned with environmental and technological extremes threatening human life and well‐being. A hazards perspective on terrorism could contribute towards defining terrorism, clarifying the contours of the terrorism discourse, root causes, and response. Insights gleaned from geographical research on social violence, technological and environmental hazards can be eminently applicable to researching various aspects of terrorism. The fundamental point is that terrorism is a deeply geographical phenomenon with potentially disastrous consequences for international peace. Beyond enhancing human safety, the geographical research agenda in terrorism will be part of the struggle to wrest control of the terrorism terminology away from the Western politico‐military elites, to keep them from using it to whip their real or imagined enemies.
Delayed pharmacological effects of proctolin and CCAP on heartbeat in pupae of the tobacco hornworm, Manduca sexta
Authors: Sláma Karel , Rosiñski Grzegorz
Published: February 2005

Abstract.  The effects in vivo of cardioactive peptides proctolin, CCAP and leucomyosuppressin (LMS) are investigated by means of noninvasive optocardiographic or thermographic techniques in postdiapause pupae of Manduca sexta. A constant pattern of heartbeat reversal in these pupae is manifested by regular alternations of the forward orientated (anterograde) and the backward orientated (retrograde) cardiac pulsations, with a periodicity of some 5–10 min. The heartbeat pattern is monitored continuously for several hours before and 24 h after injection of the investigated peptides. Injections of Ringer solution alone cause a slight, almost immediate increase of the rate of the pupal heartbeat (0–10%), which lasts only for 20–30 min. Injection of proctolin, CCAP or LMS does not show any immediate cardiostimulating effects (beyond those of Ringer) at concentrations up to 2 × 10−6 M (calculated from µg of the injected peptide and 70% pupal water content; 5–7 g pupal body mass). By contrast, injections of proctolin and CCAP in the range of 10‐9 − 10‐6 M concentrations cause delayed effects on the heartbeat, which are manifested only several hours after the injections. The delayed effects involve prolonged, or even continuous periods of unidirectional, more efficient and faster anterograde pulsations. Consequently, the flow of haemolymph through the head and thoracic parts of the pupal body increases. In the case of proctolin, the prolonged anterograde cardiac activity usually starts 5 h after the injections and the effect persists for 7–12 h. Using CCAP, the stimulation of anterograde activity starts 2.5–3 h after injections and lasts usually 7–8 h. Very small doses of peptides (10‐8 − 10‐9 M) do not change the latency period significantly, but they decrease the duration of the response. The frequency of the systolic contractions of the heart does not increase during the prolonged anterograde phase. Injections of LMS to produce a final concentration of 10−6 M in the pupa induce pathophysiological disturbances of heartbeat reversal and peristalsis. The effects start with a delay of some 1.5–2.5 h after the injections. By contrast to the effects of proctolin and CCAP, LMS does not produce delayed anterograde cardiac pulsations. These results show that the most intensively investigated cardiostimulating peptides in vitro, proctolin and CCAP, have no direct cardiostimulating activity under physiological conditions in vivo. It is concluded therefore that the delayed pharmacological effects of these peptides observed in the pupae of M. sexta, represent a secondary effect, resulting from stimulation of nonspecific, extracardiac myotropic or other physiological functions.
Comparison of cold hardiness and sugar content between diapausing and nondiapausing pupae of the cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)
Authors: Izumi Yohei , Anniwaer Kuerban , Yoshida Hideya , Sonoda Shoji , Fujisaki Kenji , Tsumuki Hisaaki
Published: February 2005

Abstract.  To understand overwintering of the cotton boll worm Helicoverpa armigera, cold hardiness and sugar content are compared between diapausing and nondiapausing pupae. Diapausing and nondiapausing pupae reared at 20 °C under short and long photoperiods are acclimatized with a reduction of 5 °C per 5 days to 0 °C. When the acclimation temperature reaches 0 °C, the survival of diapausing pupae is assessed. The survival gradually decreases as the period of treatment progresses and approximately half survive for 112 days. However, nondiapausing pupae survive only 14 days after exposure to 0 °C. The surpercooling points of nondiapausing, diapausing and acclimatized pupae are approximately −17 °C. The major sugars contained in pupae are trehalose and glucose. Even though trehalose contents in diapausing pupae (initial level: 0.6 mg 100 mg−1 fresh weight) increase significantly during cold acclimation and continue increasing until 58 days after exposure to 0 °C (maximum level: 1.8 mg 100 mg−1), glucose is maintained at low levels (0.02 mg 100 mg−1) for 56 days at 0 °C. However, glucose contents increase (maximum level: 0.8 mg 100 mg−1) with decreasing contents of trehalose 84 days after exposure to 0 °C. Glycogen content gradually decreases during cold acclimation. When nondiapausing pupae are acclimatized with a reduction of 5 °C per 5 days to 5 °C from the beginning of pupation until the eyespots move, trehalose content increases (maximum level: 1.0 mg 100 mg−1). Glucose contents in nondiapausing pupae increase before eclosion (0.09 mg 100 mg−1). From these results, diapausing pupae of H. armigera can overwinter in regions where average winter temperatures are higher than 0 °C, but nondiapausing pupae cannot.
Male sperm donation consequences in single and double matings in Anisopteromalus calandrae
Authors: Khanh Hong Do Thi , Bressac Christophe , Chevrier Claude
Published: February 2005

Abstract.  The number of spermatozoa that a male transfers to the female during copulation is a main component of its individual fitness, especially under the pressure of sperm competition. This paper presents experimental results on the direct relationship between the male's sperm investment and its paternity in the offspring of dual‐mated females. An eye colour mutant (red‐eyed) is used to study the differences in the mating and fertilization abilities of males through observation of single and dual matings of females in Anisopteromalus calandrae (Hymenoptera, Chalcidoidea, Pteromalidae). Experimentally, females accept dual matings only in the simultaneous presence of two males. Counts of spermatozoa in the seminal vesicles of virgin males show that red‐eyed males have more sperm than wild‐eyed ones (approximately 1.46‐fold greater). Red‐ and wild‐eyed males do not differ in their mating behaviour and females mate indifferently with both phenotypes. Compared with once‐mated females, double‐mated females increase neither sperm storage nor lifetime fecundity, and the offspring sex ratio is female‐biased. Females mated with two males of different phenotypes produce offspring of both phenotypes throughout their reproductive life, whatever the order of males in the copulation sequence. Any mating pattern appears to produce more red‐ than wild‐eyed offspring (between 1.45‐ and 1.88‐fold greater). Thus, proportions of offspring of each male match the proportions of their sperm potential. With no preference of female for red‐eye or wild‐eye males being demonstrated at either behavioural or physiological levels, a male's investment in sperm quantity appears to determine its individual reproductive success, at least in these experimental conditions.