bluuebunny/crossref_metadata_2025 huggingface dataset:
Powerline corridors: degraded ecosystems or wildlife havens?
Authors: Clarke Donna J. , Pearce Kate A. , White John G.
Published: December 2006

Management of powerline corridors in Australia has traditionally focused on the complete removal of vegetation using short rotation times owing to the perceived hazard of fire associated with corridor vegetation. Because of the intense management associated with fire hazards, little thought has been given to use of powerline corridors by wildlife. This has resulted in corridors traditionally being viewed as a source of fragmentation and habitat loss within forested ecosystems. We investigated the responses of small mammal communities living in a powerline corridor to management-induced vegetation changes at different successional stages, to determine whether a compromise could be reached between managing corridors for fire and biodiversity. Habitat modelling in the corridor and adjacent forest for three native and one introduced small mammal species demonstrated that species responded to changes in vegetation structural complexity, rather than time-since-management per se. Early seral stages of vegetation recovery after corridor management encouraged the introduced house mouse (Mus domesticus) into corridors and contributed little to biodiversity. Mid-seral-stage vegetation, however, provided habitat for native species that were rare in adjacent forest habitats. As the structural complexity of the vegetation increased, the small mammal community became similar to that of the forest so that corridor vegetation contributed fewer biodiversity benefits while posing an unacceptable fire risk. If ecologically sensitive management regimes are implemented to encourage mid-seral vegetation and avoid complete vegetation removal, powerline corridors have the potential to improve biodiversity. This would maintain landscape connectivity and provide habitat for native species uncommon in the forest while still limiting fuel loads in the corridor.
Dietary analysis of regurgitates and stomach samples from free-living Australian sea lions
Authors: McIntosh Rebecca R. , Page Brad , Goldsworthy Simon D.
Published: December 2006

Dietary remains recovered from Australian sea lion (Neophoca cinerea) digestive tracts and regurgitate samples from Seal Bay (Kangaroo Island, South Australia) were used to identify prey species consumed. Four of eight digestive tracts collected (50%) contained prey items located only in the stomach. On the basis of biomass reconstruction of cephalopod prey remains, octopus contributed 40% of the biomass in the samples, giant cuttlefish (Sepia apama) contributed 30% and ommastrephid squids contributed 14% biomass. The remains of several fish species were found in the samples: leatherjacket (Monocanthidae), flathead (Platycephalus sp.), swallowtail (Centroberyx lineatus), common bullseye (Pempheris multiradiata), southern school whiting (Sillago flindersi) and yellowtail mackerel (Trachurus novaezelandiae). Southern rock lobster (Jasus edwardsii) and swimming crab (Ovalipes australiensis) carapace fragments, little penguin (Eudyptula minor) feathers and bones and shark egg cases (oviparous species and Scyliorhinidae sp.) were also identified.
Single-stranded nucleic acid-induced helical self-assembly of alkynylplatinum(II) terpyridyl complexes
Authors: Yu Cong , Chan Kenneth Hoi-Yiu , Wong Keith Man-Chung , Yam Vivian Wing-Wah
Published: December 2006

Single-stranded nucleic acids, which carry multiple negative charges in an aqueous medium at near neutral pH, are found to induce the aggregation and self-assembly of the positively charged alkynylplatinum(II) terpyridyl complexes via electrostatic binding of the platinum complexes to the single-stranded nucleic acids, as revealed by the appearance of new UV-vis absorption and emission bands upon addition of single-stranded nucleic acids to a buffer solution of the complex. Changes in the intensity and pattern of circular dichroism (CD) spectroscopy are also observed, many of which are consistent with the assembly of the platinum complexes into helical structures, via metal⋯metal and π⋯π stacking interactions. The induced spectroscopic property changes are found to depend on the structural properties of the nucleic acids.
Mesodermal cell displacements during avian gastrulation are due to both individual cell-autonomous and convective tissue movements
Authors: Zamir Evan A. , Czirók András , Cui Cheng , Little Charles D. , Rongish Brenda J.
Published: December 2006

Gastrulation is a fundamental process in early development that results in the formation of three primary germ layers. During avian gastrulation, presumptive mesodermal cells in the dorsal epiblast ingress through a furrow called the primitive streak (PS), and subsequently move away from the PS and form adult tissues. The biophysical mechanisms driving mesodermal cell movements during gastrulation in amniotes, notably warm-blooded embryos, are not understood. Until now, a major challenge has been distinguishing local individual cell-autonomous (active) displacements from convective displacements caused by large-scale (bulk) morphogenetic tissue movements. To address this problem, we used multiscale, time-lapse microscopy and a particle image velocimetry method for computing tissue displacement fields. Immunolabeled fibronectin was used as an
in situ
marker for quantifying tissue displacements. By imaging fluorescently labeled mesodermal cells and surrounding extracellular matrix simultaneously, we were able to separate directly the active and passive components of cell displacement during gastrulation. Our results reveal the following: (
i
) Convective tissue motion contributes significantly to total cell displacement and must be subtracted to measure true cell-autonomous displacement; (
ii
) Cell-autonomous displacement decreases gradually after egression from the PS; and (
iii
) There is an increasing cranial-to-caudal (head-to-tail) cell-autonomous motility gradient, with caudal cells actively moving away from the PS faster than cranial cells. These studies show that, in some regions of the embryo, total mesodermal cell displacements are mostly due to convective tissue movements; thus, the data have profound implications for understanding cell guidance mechanisms and tissue morphogenesis in warm-blooded embryos.
Synthetic small molecule furin inhibitors derived from 2,5-dideoxystreptamine
Authors: Jiao Guan-Sheng , Cregar Lynne , Wang Jinzhi , Millis Sherri Z. , Tang Cho , O'Malley Sean , Johnson Alan T. , Sareth Sina , Larson Jason , Thomas Gary
Published: December 2006

Furin plays a crucial role in embryogenesis and homeostasis and in diseases such as Alzheimer's disease, cancer, and viral and bacterial infections. Thus, inhibition of furin may provide a feasible and promising approach for therapeutic intervention of furin-mediated disease mechanisms. Here, we report on a class of small molecule furin inhibitors based on 2,5-dideoxystreptamine. Derivatization of 2,5-dideoxystreptamine by the addition of guanidinylated aryl groups yielded a set of furin inhibitors with nanomolar range potency against furin when assayed in a biochemical cleavage assay. Moreover, a subset of these furin inhibitors protected RAW 264.7 macrophage cells from toxicity caused by furin-dependent processing of anthrax protective antigen. These inhibitors were found to behave as competitive inhibitors of furin and to be relatively specific for furin. Molecular modeling revealed that these inhibitors may target the active site of furin as they showed site occupancy similar to the alkylating inhibitor decanoyl-Arg-Val-Lys-Arg-CH
2
Cl. The compounds presented here are bona fide synthetic small molecule furin inhibitors that exhibit potency in the nanomolar range, suggesting that they may serve as valuable tools for studying furin action and potential therapeutics agents for furin-dependent diseases.
Multiple aromatic side chains within a disordered structure are critical for transcription and transforming activity of EWS family oncoproteins
Authors: Ng King Pan , Potikyan Gary , Savene Rupert O. V. , Denny Christopher T. , Uversky Vladimir N. , Lee Kevin A. W.
Published: January 2007

Chromosomal translocations involving the N-terminal ≈250 residues of the Ewings sarcoma (EWS) oncogene produce a group of EWS fusion proteins (EFPs) that cause several distinct human cancers. EFPs are potent transcriptional activators and interact with other proteins required for mRNA biogenesis, indicating that EFPs induce tumorigenesis by perturbing gene expression. Although EFPs were discovered more than a decade ago, molecular analysis has been greatly hindered by the repetitive EWS activation domain (EAD) structure, containing multiple degenerate hexapeptide repeats (consensus SYGQQS) with a conserved tyrosine residue. By exploiting total gene synthesis, we have been able to systematically mutagenize the EAD and determine the effect on transcriptional activation by EWS/ATF1 and cellular transformation by EWS/Fli1. In both assays, we find the following requirements for EAD function. First, multiple tyrosine residues are essential. Second, phenylalanine can effectively substitute for tyrosine, showing that an aromatic ring can confer EAD function in the absence of tyrosine phosphorylation. Third, there is little requirement for specific peptide sequences and, thus, overall sequence composition (and not the degenerate hexapeptide repeat) confers EAD activity. Consistent with the above findings, we also report that the EAD is intrinsically disordered. However, a sensitive computational predictor of natural protein disorder (PONDR VL3) identifies potential molecular recognition features that are tyrosine-dependent and that correlate well with EAD function. In summary we have uncovered several molecular features of the EAD that will impact future studies of the broader EFP family and molecular recognition by complex intrinsically disordered proteins.
Nisin-induced changes inBacillusmorphology suggest a paradigm of antibiotic action
Authors: Hyde Alexander J. , Parisot Judicaël , McNichol Adam , Bonev Boyan B.
Published: December 2006

Nisin is a small cationic lanthionine antibiotic produced byLactococcus lactis. During its antimicrobial action, it targets intermediates in the bacterial cell-wall biosynthesis, lipid II, and undecaprenyl pyrophosphate. Here, we report results from electron microscopic investigations of the effects of lethal nisin doses onBacillus subtiliscell morphology. Bacterial membranes were permeabilized shortly afterB. subtiliswas incubated with nisin, but this did not lead to immediate cell death. Cell division, as well as other life functions, persisted over at least half an hour after nisin was added. Slower bacterial elongation, consistent with cell envelope inhibition and accelerated division, resulted in cell-length reduction. Abnormal morphogenesis near the division site suggests this to be the primary site of nisin action. Morphological changes are characteristic of deregulation of a filamentous cell envelope protein, Mbl, and the division-inhibiting Min system. We propose a previously undescribed model, in which the lethal action of nisin againstB. subtilisstarts with membrane permeabilization and is followed by accelerated cell division, cell envelope inhibition, and aberrant cell morphogenesis.
Identification of quantitative trait loci affecting body composition in a mouse intercross
Authors: Vitarius James A. , Sehayek Ephraim , Breslow Jan L.
Published: December 2006

Gravimetric analysis and dual energy x-ray absorptiometry densitometry were used to determine lean, fat, and bone tissue traits in a F
2
mouse population from a C57BL/6J and CASA/Rk intercross (B6CASAF2). These traits were used in a linkage analysis to identify quantitative trait loci that affect body composition. Linkage mapping showed that body weight (BW) loci on proximal chromosome 2 occurred in the same region as body length, lean tissue mass, and bone mineral content and on chromosome 13 in the same region as lean tissue mass, bone mineral density, and bone mineral content. Fat-related loci occurring on mid-chromosome 2 near 60 cM, proximal chromosome 6, and mid-chromosome 10 were distinct from BW, lean tissue, and bone tissue loci. In B6CASAF2 females, heterozygotes and CASA/Rk homozygotes at the chromosome 6 locus marker had higher body fat percentages, and this locus was responsible for 11% of the variance for body fat percentage. Female heterozygotes and C57BL/6J homozygotes at the chromosome 15 locus marker had higher bone mineral densities, and this locus could explain 8% of that trait's variance. A survey of the literature did not reveal any previous reports of fat-specific loci in the chromosomal 10 region near 42 cM reported in this study. The results of this study indicate that BW and BMI have limited usefulness as phenotypes in linkage or association studies when used as obesity phenotypes.
Anisotropy of cell adhesive microenvironment governs cell internal organization and orientation of polarity
Authors: Théry Manuel , Racine Victor , Piel Matthieu , Pépin Anne , Dimitrov Ariane , Chen Yong , Sibarita Jean-Baptiste , Bornens Michel
Published: December 2006

Control of the establishment of cell polarity is an essential function in tissue morphogenesis and renewal that depends on spatial cues provided by the extracellular environment. The molecular role of cell–cell or cell–extracellular matrix (ECM) contacts on the establishment of cell polarity has been well characterized. It has been hypothesized that the geometry of the cell adhesive microenvironment was directing cell surface polarization and internal organization. To define how the extracellular environment affects cell polarity, we analyzed the organization of individual cells plated on defined micropatterned substrates imposing cells to spread on various combinations of adhesive and nonadhesive areas. The reproducible normalization effect on overall cell compartmentalization enabled quantification of the spatial organization of the actin network and associated proteins, the spatial distribution of microtubules, and the positioning of nucleus, centrosome, and Golgi apparatus. By using specific micropatterns and statistical analysis of cell compartment positions, we demonstrated that ECM geometry determines the orientation of cell polarity axes. The nucleus–centrosome orientations were reproducibly directed toward cell adhesive edges. The anisotropy of the cell cortex in response to the adhesive conditions did not affect the centrosome positioning at the cell centroid. Based on the quantification of microtubule plus end distribution we propose a working model that accounts for that observation. We conclude that, in addition to molecular composition and mechanical properties, ECM geometry plays a key role in developmental processes.
Mechanism of allosteric regulation of transglutaminase 2 by GTP
Authors: Begg Gillian E. , Carrington Lyle , Stokes Philippa H. , Matthews Jacqueline M. , Wouters Merridee A. , Husain Ahsan , Lorand Laszlo , Iismaa Siiri E. , Graham Robert M.
Published: December 2006

Allosteric regulation is a fundamental mechanism of biological control. Here, we investigated the allosteric mechanism by which GTP inhibits cross-linking activity of transglutaminase 2 (TG2), a multifunctional protein, with postulated roles in receptor signaling, extracellular matrix assembly, and apoptosis. Our findings indicate that at least two components are involved in functionally coupling the allosteric site and active center of TG2, namely (
i
) GTP binding to mask a conformationally destabilizing switch residue, Arg-579, and to facilitate interdomain interactions that promote adoption of a compact, catalytically inactive conformation and (
ii
) stabilization of the inactive conformation by an uncommon H bond between a cysteine (Cys-277, an active center residue) and a tyrosine (Tyr-516, a residue located on a loop of the β-barrel 1 domain that harbors the GTP-binding site). Although not essential for GTP-mediated inhibition of cross-linking, this H bond enhances the rate of formation of the inactive conformer.
Transcriptional Profiles in Liver from Rats Treated with Tumorigenic and Non-tumorigenic Triazole Conazole Fungicides: Propiconazole, Triadimefon, and Myclobutanil
Authors: Hester Susan D. , Wolf Douglas C. , Nesnow Stephen , Thai Sheau-Fung
Published: December 2006

Conazoles are a class of fungicides used as pharmaceutical and agricultural agents. In chronic bioassays in rats, triadimefon was hepatotoxic and induced follicular cell adenomas in the thyroid gland, whereas, propiconazole and myclobutanil were hepatotoxic but had no effect on the thyroid gland. These conazoles administered in the feed to male Wistar/Han rats were found to induce hepatomegaly, induce high levels of pentoxyresorufin-O-dealkylase, increase cell proliferation in the liver, increase serum cholesterol, decrease serum T3 and T4, and increase hepatic uridine diphospho-glucuronosyl transferase activity. The goal of the present study was to define pathways that explain the biologic outcomes. Male Wistar/Han rats (3 per group), were exposed to the 3 conazoles in the feed for 4, 30, or 90 days of treatment at tumorigenic and nontumorigenic doses. Hepatic gene expression was determined using high-density Affymetrix GeneChips (Rat 230_2). Differential gene expression was assessed at the probe level using Robust Multichip Average analysis. Principal component analysis by treatment and time showed within group sample similarity and that the treatment groups were distinct from each other. The number of altered genes varied by treatment, dose, and time. The greatest number of altered genes was induced by triadimefon and propiconazole after 90 days of treatment, while myclobutanil had minimal effects at that time point. Pathway level analyses revealed that after 90 days of treatment the most significant numbers of altered pathways were related to cell signaling, growth, and metabolism. Pathway level analysis for triadimefon and propiconazole resulted in 71 altered pathways common to both chemicals. These pathways controlled cholesterol metabolism, activation of nuclear receptors, and N- ras and K- ras signaling. There were 37 pathways uniquely changed by propiconazole, and triadimefon uniquely altered 34 pathways. Pathway level analysis of altered gene expression resulted in a more complete description of the associated toxicological effects that can distinguish triadimefon from propiconazole and myclobutanil.
Transcriptional Profiles in Liver from Mice Treated with Hepatotumorigenic and Nonhepatotumorigenic Triazole Conazole Fungicides: Propiconazole, Triadimefon, and Myclobutanil
Authors: Ward William O. , Delker Don A. , Hester Susan D. , Thai Sheau-Fung , Wolf Douglas C. , Allen James W. , Nesnow Stephen
Published: December 2006

Conazoles are environmental and pharmaceutical fungicides. The present study relates the toxicological effects of conazoles to alterations of gene and pathway transcription and identifies potential modes of tumorigenic action. In a companion study employing conventional toxicological bioassays ( Allen et al., 2006 ), male CD-1 mice were fed triadimefon, propiconazole, or myclobutanil in a continuous oral-dose regimen for 4, 30, or 90 days. These conazoles were found to induce hepatomegaly, to induce high levels of hepatic pentoxyresorufin-O-dealkylase activity, to increase hepatic cell proliferation, to decrease serum cholesterol, and to increase serum triglycerides. Differentially expressed genes and pathways were identified using Affymetrix GeneChips. Gene-pathway associations were obtained from the Kyoto Encyclopedia of Genes and Genomes, Biocarta, and MetaCore compendia. The pathway profiles of each conazole were different at each time point. In general, the number of altered metabolism, signaling, and growth pathways increased with time and dose and were greatest with propiconazole. All conazoles had effects on nuclear receptors as evidenced by increased expression and enzymatic activities of a series of related cytochrome P450s (CYP). A subset of altered genes and pathways distinguished the three conazoles from each other. Triadimefon and propiconazole both altered apoptosis, cell cycle, adherens junction, calcium signaling, and EGFR signaling pathways. Triadimefon produced greater changes in cholesterol biosynthesis and retinoic acid metabolism genes and in selected signaling pathways. Propiconazole had greater effects on genes responding to oxidative stress and on the IGF/P13K/AKt/PTEN/mTor and Wnt-β-catenin pathways. In conclusion, while triadimefon, propiconazole, and myclobutanil had similar effects in mouse liver on hepatomegaly, histology, CYP activities, cell proliferation, and serum cholesterol, genomic analyses revealed major differences in their gene expression profiles.
Defining a Noncarcinogenic Dose of Recombinant Human Parathyroid Hormone 1–84 in a 2-Year Study in Fischer 344 Rats
Authors: Jolette Jacquelin , Wilker Clynn E. , Smith Susan Y. , Doyle Nancy , Hardisty Jerry F. , Metcalfe Anna J. , Marriott Thomas B. , Fox John , Wells David S.
Published: December 2006

The carcinogenic potential of human parathyroid hormone 1–84 (PTH) was assessed by daily subcutaneous injection (0, 10, 50, 150 μg/kg/day) for 2 years in Fischer 344 rats. Histopathological analyses were conducted on the standard set of soft tissues, tissues with macroscopic abnormalities, selected bones, and bones with abnormalities identified radiographically. All PTH doses caused widespread osteosclerosis and significant, dose-dependent increases in femoral and vertebral bone mineral content and density. In the mid- and high-dose groups, proliferative changes in bone increased with dose. Osteosarcoma was the most common change, followed by focal osteoblast hyperplasia, osteoblastoma, osteoma and skeletal fibrosarcoma. The incidence of bone neoplasms was comparable in control and low-dose groups providing a noncarcinogenic dose for PTH of 10 μg/kg/day at a systemic exposure to PTH that is 4.6-fold higher than for a 100 μg dose in humans. The ability of PTH to interact with and balance the effects of both the PTH-1 receptor and the putative C-terminal PTH receptor, may lead to the lower carcinogenic potential observed with PTH than reported previously for teriparatide.
Application of Visualization Tools to the Analysis of Histopathological Data Enhances Biological Insight and Interpretation
Authors: Lobenhofer Edward K. , Boorman Gary A. , Phillips Kenneth L. , Heinloth Alexandra N. , Malarkey David E. , Blackshear Pamela E. , Houle Christopher , Hurban Patrick
Published: December 2006

Gene expression profiling, metabolomic screens, and other high-dimensional methods have become an integral part of many biological investigations. To facilitate interpretation of these data, it is important to have detailed phenotypic data—including histopathology—to which these data can be associated, or anchored. However, as the amount of phenotypic data increases, associations within and across these data can be difficult to visualize and interpret. We have developed an approach for categorizing and clustering biologically related histopathological diagnoses to facilitate their visualization, thereby increasing the possibility of identifying associations and facilitating the comparison with other data streams. In this study, we utilize histopathological data generated as part of a standardized toxicogenomics compendium study to generate composite histopathological scores and to develop visualizations that facilitate biological insight. The validity of this approach is illustrated by the identification of transcripts that correlate with the pathology diagnoses that comprise the categories of “response to hepatocellular injury” and “repair.” This approach is broadly applicable to studies in which histopathology is used to phenotypically anchor other data, and results in visualizations that facilitate biological interpretation and the identification of associations and relationships within the data.
Translocation Pathway of the Intratracheally Instilled Ultrafine Particles from the Lung into the Blood Circulation in the Mouse
Authors: Shimada Akinori , Kawamura Natsuko , Okajima Mina , Kaewamatawong Theerayuth , Inoue Hiromi , Morita Takehito
Published: December 2006

Recently, it has been demonstrated that ultrafine particles (UFPs) are able to translocate from the lung into the systemic circulation. Precise mechanisms of the anatomical translocation (crossing the air–blood barrier) of inhaled UFPs at the alveolar wall are not fully understood. In this study, we examined the translocation pathway of the intratracheally instilled ultrafine carbon black (UFCB) from the lung into the blood circulation in mouse. Electron microscopy demonstrated accumulation of intratracheally instilled UFCB in the large-sized gaps developing between the cytoplasmic processes of the alveolar epithelial cells, possibly as a result of shrinkage of cytoplasm, by receiving stimulus/signals generated and released following UFCB attachment on the alveolar epithelial cells. Occasional penetration of the accumulated UFCB into the alveolar basement membrane, exposing to the air space, was observed at the gap. These results suggest that inhaled UFPs may, in part, pass the air-blood barrier through the large-sized gap formed between the alveolar epithelial cells.
Histological Investigation of Diagnostically Challenging Tubule Profiles in Advanced Chronic Progressive Nephropathy (CPN) in the Fischer 344 RaT
Authors: Hard Gordon C. , Seely John Curtis
Published: December 2006

Recently, guidelines were suggested for discriminating proliferative-appearing tubule profiles encountered in advanced spontaneous chronic progressive nephropathy (CPN) of rats, from hyperplastic precursors of renal tubule tumors ( Hard and Seely, 2005 ). These recommendations were based on histological evaluation of a large number of cases of severe to end-stage CPN in male F344 rats from 8 separate 2-year carcinogenicity studies held in the Archives of the National Toxicology Program, NIEHS. This work has now been extended to characterize the various lesions further, mainly by serial sectioning to track their origin and fate within the adjacent renal tissue, but also by applying special staining procedures such as immunohistochemical assessment of proliferative activity, as well as fluorescence microscopy, to seek further differences from atypical tubule hyperplasia. The results obtained from these additional investigations support the contention that certain tubule profiles with a misleading proliferative appearance, sometimes found in advanced CPN, should be distinguished from preneoplastic tubule foci, and regarded as components of the nephropathy process.
Control of gene conversion and somatic hypermutation by immunoglobulin promoter and enhancer sequences
Authors: Yang Shu Yuan , Fugmann Sebastian D. , Schatz David G.
Published: December 2006

It is thought that gene conversion (GCV) and somatic hypermutation (SHM) of immunoglobulin (Ig) genes occur in two steps: the generation of uracils in DNA by activation-induced cytidine deaminase, followed by their subsequent repair by various DNA repair pathways to generate sequence-diversified products. It is not known how either of the two steps is targeted specifically to Ig loci. Because of the tight link between transcription and SHM, we have investigated the role of endogenous Ig light chain (IgL) transcriptional control elements in GCV/SHM in the chicken B cell line DT40. Promoter substitution experiments led to identification of a strong RNA polymerase II promoter incapable of supporting efficient GCV/SHM. This surprising finding indicates that high levels of transcription are not sufficient for robust GCV/SHM in Ig loci. Deletion of the IgL enhancer in a context in which high-level transcription was not compromised showed that the enhancer is not necessary for GCV/SHM. Our results indicate that cis-acting elements are important for Ig gene diversification, and we propose that targeting specificity is achieved through the combined action of several Ig locus elements that include the promoter.
IL-21–induced Bε cell apoptosis mediated by natural killer T cells suppresses IgE responses
Authors: Harada Michishige , Magara-Koyanagi Kumiko , Watarai Hiroshi , Nagata Yuko , Ishii Yasuyuki , Kojo Satoshi , Horiguchi Shigetoshi , Okamoto Yoshitaka , Nakayama Toshinori , Suzuki Nobutaka , Yeh Wen-Chen , Akira Shizuo , Kitamura Hiroshi , Ohara Osamu , Seino Ken-ichiro , Taniguchi Masaru
Published: December 2006

Epidemiological studies have suggested that the recent increase in the incidence and severity of immunoglobulin (Ig)E-mediated allergic disorders is inversely correlated with Mycobacterium bovis bacillus Calmette Guerin (BCG) vaccination; however, the underlying mechanisms remain uncertain. Here, we demonstrate that natural killer T (NKT) cells in mice and humans play a crucial role in the BCG-induced suppression of IgE responses. BCG-activated murine Vα14 NKT cells, but not conventional CD4 T cells, selectively express high levels of interleukin (IL)-21, which preferentially induces apoptosis in Bε cells. Signaling from the IL-21 receptor increases the formation of a complex between Bcl-2 and the proapoptotic molecule Bcl-2–modifying factor, resulting in Bε cell apoptosis. Similarly, BCG vaccination induces IL-21 expression by human peripheral blood mononuclear cells (PBMCs) in a partially NKT cell–dependent fashion. BCG-activated PBMCs significantly reduce IgE production by human B cells. These findings provide new insight into the therapeutic effect of BCG in allergic diseases.
Completeness of systems of complex exponentials and the Lambert 𝑊 functions
Authors: Boivin André , Zhong Hualiang
Published: December 2006

We study some of the properties of the solution system

{

e

i

λ
n

t

}

\{e^{i\lambda _nt}\}

of the delay-differential equation

y
′

(
t
)
=
a
y
(
t
−
1
)

y’(t) = ay(t-1)

. We first establish some general results on the stability of the completeness of exponential systems in

L
2

L^2

and then show that the solution system above is always complete, but is not an unconditional basis in

L
2

(
−
1

/

2
,
1

/

2
)

L^2(-1/2,1/2)

.
Geodesics in Randers spaces of constant curvature
Authors: Robles Colleen
Published: December 2006

Geodesics in Randers spaces of constant curvature are classified.
A skein-like multiplication algorithm for unipotent Hecke algebras
Authors: Thiem Nathaniel
Published: December 2006

Let

G
G

be a finite group of Lie type (e.g.

G

L
n

(

F

q

)

GL_n(\mathbb {F}_q)

) and

U
U

a maximal unipotent subgroup of

G
G

. If

ψ
\psi

is a linear character of

U
U

, then the unipotent Hecke algebra is
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="script upper H Subscript psi Baseline equals normal upper E normal n normal d Subscript double-struck upper C upper G Baseline left-parenthesis normal upper I normal n normal d Subscript upper U Superscript upper G Baseline left-parenthesis psi right-parenthesis right-parenthesis">

H

ψ

=

E
n
d

C

G

(

I
n
d

U
G

(
ψ
)
)

\mathcal {H}_\psi =\mathrm {End}_{\mathbb {C}G} (\mathrm {Ind}_U^G(\psi ))

. Unipotent Hecke algebras have a natural basis coming from double cosets of

U
U

in

G
G

. This paper describes relations for reducing products of basis elements, and gives a detailed description of the implications in the case

G
=
G

L
n

(

F

q

)

G=GL_n(\mathbb {F}_q)

.
Numerical Godeaux surfaces with an involution
Authors: Calabri Alberto , Ciliberto Ciro , Mendes Lopes Margarida
Published: December 2006

Minimal algebraic surfaces of general type with the smallest possible invariants have geometric genus zero andK2=1K^2=1and are usually callednumerical Godeaux surfaces. Although they have been studied by several authors, their complete classification is not known. In this paper we classify numerical Godeaux surfaces with an involution, i.e. an automorphism of order 2. We prove that they are birationally equivalent either to double covers of Enriques surfaces or to double planes of two different types: the branch curve either has degree 10 and suitable singularities, originally suggested by Campedelli, or is the union of two lines and a curve of degree 12 with certain singularities. The latter type of double planes are degenerations of examples described by Du Val, and their existence was previously unknown; we show some examples of this new type, also computing their torsion group.
Lusternik-Schnirelmann category of 𝐒𝐩𝐢𝐧(9)
Authors: Iwase Norio , Kono Akira
Published: December 2006

First we give an upper bound of

c
a
t

(
E
)

\mathrm {cat}{(E)}

, the L-S category of a principal

G
G

-bundle

E
E

for a connected compact group

G
G

with a characteristic map

α
:

Σ

V
→
G

\alpha : {\Sigma }V \to G

. Assume that there is a cone-decomposition

{

F

i

|

0
≤
i
≤
m
}

\{F_{i}\,\vert \,0 \leq i\leq m\}

of

G
G

in the sense of Ganea that is compatible with multiplication. Then we have

c
a
t

(
E
)

≤

M
a
x

(
m

+

n
,
m

+

2
)

\mathrm {cat}{(E)} \leq \mathrm {Max}(m{+}n,m{+}2)

for

n
≥
1

n \geq 1

, if

α
\alpha

is compressible into

F

n

⊆

F

m

≃
G

F_{n} \subseteq F_{m}\simeq G

with trivial higher Hopf invariant

H
n

(
α
)

H_n(\alpha )

. Second, we introduce a new computable lower bound,

M
w
g
t

(
X
;

F

2

)

\mathrm {Mwgt} {(X; {\mathbb {F}_2}})

for

c
a
t

(

X

)

\mathrm {cat}({X})

. The two new estimates imply
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal c normal a normal t left-parenthesis bold upper S bold p bold i bold n left-parenthesis 9 right-parenthesis right-parenthesis equals normal upper M normal w normal g normal t left-parenthesis bold upper S bold p bold i bold n left-parenthesis 9 right-parenthesis semicolon double-struck upper F 2 right-parenthesis equals 8 greater-than 6 equals normal w normal g normal t left-parenthesis bold upper S bold p bold i bold n left-parenthesis 9 right-parenthesis semicolon double-struck upper F 2 right-parenthesis">

c
a
t

(

S
p
i
n

(
9
)
)

=

M
w
g
t

(

S
p
i
n

(
9
)

;

F

2

)
=
8
>
6
=

w
g
t

(

S
p
i
n

(
9
)

;

F

2

)

\mathrm {cat}({\mathbf {Spin}{(9))}}=\mathrm {Mwgt} ({\mathbf {Spin}{(9)};{\mathbb {F}_2}}) = 8 > 6 =\mathrm {wgt}({\mathbf {Spin}{(9)};{\mathbb {F}_2}})

, where

(

w
g
t

−
;
R

)

(\mathrm {wgt}{-;R})

is a category weight due to Rudyak and Strom.
The semiclassical structure of low-energy states in the presence of a magnetic field
Authors: Borthwick David , Uribe Alejandro
Published: December 2006

We consider a compact Riemannian manifold with a Hermitian line bundle whose curvature is non-degenerate. The Laplacian acting on high tensor powers (the semiclassical regime) of the bundle exhibits a cluster of low-energy states. We demonstrate that the orthogonal projectors onto these states are the Fourier components of an operator with the structure of the Szegö projector, i.e. a Fourier integral operator of Hermite type. This result yields semiclassical asymptotics for the low-energy eigenstates.
A generalization of half-plane mappings to the ball in ℂⁿ
Authors: Muir Jerry , Suffridge Ted
Published: December 2006

Let

F
F

be a normalized (

F
(
0
)
=
0

F(0)=0

,

D
F
(
0
)
=
I

DF(0)=I

) biholomorphic mapping of the unit ball

B
⊆

C

n

B \subseteq \mathbb C^n

onto a convex domain

Ω
⊆

C

n

\Omega \subseteq \mathbb C^n

that is the union of lines parallel to some unit vector

u
∈

C

n

u \in \mathbb C^n

. We consider the situation in which there is one infinite singularity of

F
F

on

∂
B

\partial B

. In one case with a simple change-of-variables, we classify all convex mappings of

B
B

that are half-plane mappings in the first coordinate. In the more complicated case, when

u
u

is not in the span of the infinite singularity, we derive a form of the mappings in dimension

n
=
2

n=2

.
All 𝑝-local finite groups of rank two for odd prime 𝑝
Authors: Díaz Antonio , Ruiz Albert , Viruel Antonio
Published: December 2006

In this paper we give a classification of the rank two

p
p

-local finite groups for odd 

p
p

. This study requires the analysis of the possible saturated fusion systems in terms of the outer automorphism group of the possible

F

\mathcal {F}

-radical subgroups. Also, for each case in the classification, either we give a finite group with the corresponding fusion system or we check that it corresponds to an exotic

p
p

-local finite group, getting some new examples of these for 

p
=
3

p=3

.
Frederic Wood Jones, 1879-1954
Authors: Gros Clark Wilfrid Edward Le
Published: December 2006

Frederic Wood Jones was born in London on 23 January 1879, the son of an architect of Welsh descent. As a boy he was a keen entomologist and showed an unusual interest in all branches of natural history. These pursuits engaged much of his attention during his school days and, with a number of interruptions due to ill-health, no doubt accounted for the fact that his school career was quite undistinguished, and that he also found some difficulty in passing the examination for the London University Matriculation. He finally matriculated in 1897 and entered the London Hospital as a medical student. It was here that he first showed evidence of his intellectual ability, for he won a succession of scholarships and prizes in anatomy, physiology and clinical medicine. It was at the London Hospital, also, that Wood Jones came under the influence of Chalmers Mitchell and Arthur Keith, to both of whom he later recorded his debt of gratitude for their stimulating influence. He qualified with the degrees of M.B., B.S. in 1904, and even while a student he had already contributed to the
Proceedings of the Journal of Anatomy & Physiology
(as it was then called) short notes on the musculature of the bladder and urethra, the development of the fundus of the stomach, and a method of reconstruction of a human embryo by photographic reproductions of serial sections. These early publications showed a certain originality of approach which was later to become a very characteristic quality of Wood Jones’s work. It is not surprising, therefore, that his teachers and friends hoped that, on qualification, he would settle down to an academic career in London. But, against all their advice, he left England in January 1905 to take up an appointment as Medical Officer to the Eastern Extension Telegraph Company in the Far East, and, after a short stay in Singapore, sailed for the Cocos-Keeling Islands. We do not know what decided him on this course, but it clearly fits into the pattern of the whole of his subsequent career, for he was essentially a wanderer and a seeker after adventure; indeed, he never stayed in any of the numerous positions which he held for more than a few years.
Arthur Keith, 1866-1955
Authors: Gros Clark Wilfrid Edward Le
Published: December 2006

The death of Sir Arthur Keith on 7 January 1955, brought to an end an unusually active and varied career in anatomy and anthropology which had extended over more than sixty years. Of these, a quarter of a century was spent in the Royal College of Surgeons where Keith occupied with great distinction the position of Conservator of the Hunterian Museum. Arthur Keith was born on 5 February 1866 at Old Machar in Aberdeenshire, the son of a farmer, John Keith, and the sixth of his ten children. At the age of sixteen he left school with the intention of taking up farming, but a young undergraduate of Aberdeen University who came to lodge at the farm inspired him with the idea of an academic career. Accordingly, his father sent him to Gordon’s College in order to get grounded in Latin and Greek, and in 1884 he entered Marischal College as a medical student. It was here that Keith came under the influence of James Trail the botanist and John Struthers the anatomist, both of whom evidently provided a powerful inspiration which focused his attention on a scientific career. At the end of his first year he won a prize ‘for the highest distinction in the junior division of the anatomy class’—the prize being a copy of the
Origin of species
. He was also awarded a scholarship of which he was very badly in need at the time, for his father’s death shortly before had imposed a severe financial strain on his family.
George Martin Lees, 1898 - 1955
Authors: Arkell William Joscelyn
Published: December 2006

George Martin Lees, son of George Murray Lees of Edinburgh, was born at Dundalk, County Louth, Ireland, on 16 April 1898. He was educated at St Andrews College, Dublin (1906-1915) and immediately thereafter attended the Royal Military Academy, Woolwich, in preparation for taking part in the first world war, then in progress. From Woolwich he was commissioned in the Royal Artillery, in which he served in France. He soon transferred to the Royal Flying Corps and won the M.C. There followed a tour of duty as a flying instructor in Egypt, where he gained his first experience of the Middle East, a region on which he was later to become the leading geological authority. From Egypt he moved to Mesopotamia (now Iraq) and saw further active service in air operations, for which he was awarded the D.F.C. He took part in the capture of Kirkuk from the Turks and made a forced landing behind the Turkish lines in what is now the great Kirkuk oilfield, regaining the British lines with difficulty on foot.
John Edward Lennard-Jones, 1894-1954
Authors: Mott Nevill Francis
Published: December 2006

John Lennard-Jones was born on 27 October 1894 in Leigh, Lancashire and was educated at Leigh Grammar School, where he specialized in classics. In 1912 he entered Manchester University, changed his subject to mathematics in which he took an honours degree and then an M.Sc. under Professor Lamb, carrying out some research on the theory of sound. In 1915 he joined the Royal Flying Corps, obtained his Wings in 1917 and saw service in France; he also took part in some investigations on aerodynamics with Messrs Boulton and Paul and at the National Physical Laboratory. In 1919 he returned to the University of Manchester as lecturer in mathematics, took the degree of D.Sc. of that university and continued to work on vibrations in gases, becoming more and more interested in the gas-kinetic aspects of the subject as his paper of 1922 in the
Philosophical Transactions of the Royal Society
shows. In 1922, on the advice of Professor Sydney Chapman, he applied for and was elected to a Senior 1851 Exhibition to enable him to work in Cambridge, where he became a research student at Trinity College and was awarded the degree of Ph.D. in 1924. At Cambridge under the influence of R. H. Fowler he became more and more interested in the forces between atoms and molecules and in the possibility of deducing them from the behaviour of gases.
Redcliffe Nathan Salaman, 1874-1955
Authors: Smith Kenneth Manley
Published: December 2006

Redcliffe Nathan Salaman was born on 12 September 1874; he was ninth of a family of fifteen, of whom fourteen, seven boys and seven girls, survived as adults. The family home at that time was Redcliffe Gardens, London, S.W., and this was the origin of Salaman’s first name. His father was Myer Salaman who was born in 1835 and died in 1896; his mother Sarah Salaman was born in 1845 and she died in 1931. Salaman’s great grandfather was Aaron Solomon, a well-to-do merchant who lived in a country house in Edmonton and who manufactured and dealt in Leghorn hats. His grandfather, Isaac, was the youngest son of Aaron, born in 1790; he left home for some reason unknown and joined the Navy as a common sailor. He was bought out by distant relatives and returning home changed his name to Salaman. Redcliffe Salaman was twice married, his first wife, Nina, whom he married in 1901, was the daughter of Arthur and Louisa Davis. Her father, an engineer, was also a distinguished scholar who specialized on the Massoretic Text of the Bible. Nina herself was an outstanding scholar of the Spanish Hebrew period; she died in 1925. By his first wife Salaman had six children, the eldest, Myer, is Pathologist at the London Hospital, Cancer Research. The second son, Arthur, is a doctor in general practice and a twin brother, Edward, died at the age of 9. The fourth son, Raphael, is an engineer, and of the two daughters one, Ruth, is an artist and the other, Esther, a singer.
Henry Frederick Baker, 1866-1956
Authors: Hodge William Vallance Douglas
Published: December 2006

Henry Frederick Baker, who died in Cambridge on 17 March 1956, was at the time of his death the senior Fellow of the Royal Society, having been elected in 1898. To the present generation of mathematicians he is known chiefly as the founder of a vigorous school of geometry, but in fact his contributions to knowledge in that field, to which the second half of his life was devoted, only represent about half of his mathematical work, and the range which he covered goes far beyond the bounds of geometry. While much of his earlier work has been overtaken by the march of time, his contributions to the theory of functions, differential equations, and continuous groups had in their day as much influence as his later work on geometry, and any attempt to review Baker’s contributions to mathematics must take as much account of his early work as of his later contributions. Baker was born in Cambridge on 3 July 1866, the son of Henry Baker and his wife Sarah Anne. Little is known about his early years in Cambridge, but at the age of eleven he came under instruction from the Rev. Frederick Hatt, later headmaster of Moulton Grammar School, Spalding, who sent him in for the examinations of the Science and Art Department of the Committee in Council on Education. The examinations were on sound, light and heat, electricity and magnetism, animal physiology, physiography, geology, and mathematics. In later years, Baker referred to this period of his life more than once, attributing to the instruction he then received his lasting interest in natural science, and in particular he gratefully acknowledged the debt he owed to Mr Hatt. Except for mathematics, which was a regular school subject, the instruction he received consisted of one lecture a week on each subject. The pupils took no notes, and little practical work was done, but they were encouraged to do things for themselves.