bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-temperature electronic structures and intramolecular interaction of oligofluorenes studied by synchrotron photoemission spectroscopy
Authors: Lee Guan-Ru , Chen Yu-Hung , Lin Chang-Ting , Wu Chih-I , Pi Tun-Wen , Wu Chung-Chih , Wong Ken-Tsung
Published: August 2009

Influences of temperature and intramolecular interaction on the electronic structures of oligofluorenes were systematically studied via synchrotron radiation photoemission spectroscopy and quantum chemical calculations. Our results show that the oligofluorene thin films deposited at substrates of different temperatures will alter the electronic structures, which results from the change of interunit angles in 2,7-bis[9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl)fluorine molecules. The fluorene-units at low temperature are almost perpendicular to each other and the interunit angle of stable state is 41° at room temperature.
Granular magnetoresistance in cobalt/poly (3-hexylthiophene, 2, 5-diyl) hybrid thin films prepared by a wet chemical method
Authors: Wen Tianlong , Liu Dan , Luscombe Christine K. , Krishnan Kannan M.
Published: August 2009

Cobalt/poly (3-hexylthiophene, 2, 5-diyl) (P3HT) hybrid thin films were prepared by a wet chemical method. Their microstructure consists of a nanoscale mixture of a crystalline P3HT matrix, interspersed with amorphous P3HT regions containing the cobalt nanoparticles. Magnetic and transport measurements are consistent with this microstructure and the temperature dependence of the resistance of these hybrid systems is well-fitted (R2=0.9993) to the fluctuation induced tunneling model. Moreover, by applying a magnetic field, a magnetoresistance ratio of 3% was observed in 17 vol % Co hybrid films at 10 K.
Effect of strain on quantum efficiency of InAlN-based solar-blind photodiodes
Authors: Chen Z. T. , Sakai Y. , Zhang J. C. , Egawa T. , Wu J. J. , Miyake H. , Hiramatsu K.
Published: August 2009

A series of InxAl1−xN-based Schottky solar-blind photodiodes are fabricated on the InxAl1−xN epilayers with high and very close crystal qualities. The quantum efficiency varies from 14.5% to 68.5%. The microstructure and strain state of epilayers are investigated in detail. It is found that the quantum efficiency of photodiode depends on the strain state in InxAl1−xN films. This indicates that adjusting the strain state in InxAl1−xN film is one of the promising approaches to optimize the performance of InAlN-based solar-blind photodiode.
Single source coherent anti-Stokes Raman microspectroscopy using spectral focusing
Authors: Langbein Wolfgang , Rocha-Mendoza Israel , Borri Paola
Published: August 2009

We demonstrate coherent anti-Stokes Raman scattering (CARS) microspectroscopy using a single Ti:sapphire laser oscillator and simple passive optical elements. Spectral selection by dichroic mirrors and linear chirping by glass elements creates a vibrational excitation tuneable over a large spectral range (∼800–2200 cm−1) with adjustable spectral resolution (∼10–100 cm−1). We furthermore demonstrate the applicability of differential CARS, enhancing the chemical selectivity, with the proposed single-laser configuration.
Selective activation of the M
1
muscarinic acetylcholine receptor achieved by allosteric potentiation
Authors: Ma Lei , Seager Matthew A. , Wittmann Marion , Jacobson Marlene , Bickel Denise , Burno Maryann , Jones Keith , Graufelds Valerie Kuzmick , Xu Guangping , Pearson Michelle , McCampbell Alexander , Gaspar Renee , Shughrue Paul , Danziger Andrew , Regan Christopher , Flick Rose , Pascarella Danette , Garson Susan , Doran Scott , Kreatsoulas Constantine , Veng Lone , Lindsley Craig W. , Shipe William , Kuduk Scott , Sur Cyrille , Kinney Gene , Seabrook Guy R. , Ray William J.
Published: August 2009

The forebrain cholinergic system promotes higher brain function in part by signaling through the M
1
muscarinic acetylcholine receptor (mAChR). During Alzheimer's disease (AD), these cholinergic neurons degenerate, therefore selectively activating M
1
receptors could improve cognitive function in these patients while avoiding unwanted peripheral responses associated with non-selective muscarinic agonists. We describe here benzyl quinolone carboxylic acid (BQCA), a highly selective allosteric potentiator of the M
1
mAChR. BQCA reduces the concentration of ACh required to activate M
1
up to 129-fold with an inflection point value of 845 nM. No potentiation, agonism, or antagonism activity on other mAChRs is observed up to 100 μM. Furthermore studies in M
1
−/−
mice demonstrates that BQCA requires M
1
to promote inositol phosphate turnover in primary neurons and to increase c-fos and arc RNA expression and ERK phosphorylation in the brain. Radioligand-binding assays, molecular modeling, and site-directed mutagenesis experiments indicate that BQCA acts at an allosteric site involving residues Y179 and W400. BQCA reverses scopolamine-induced memory deficits in contextual fear conditioning, increases blood flow to the cerebral cortex, and increases wakefulness while reducing delta sleep. In contrast to M
1
allosteric agonists, which do not improve memory in scopolamine-challenged mice in contextual fear conditioning, BQCA induces β-arrestin recruitment to M
1
, suggesting a role for this signal transduction mechanism in the cholinergic modulation of memory. In summary, BQCA exploits an allosteric potentiation mechanism to provide selectivity for the M
1
receptor and represents a promising therapeutic strategy for cognitive disorders.
C2′-endo nucleotides as molecular timers suggested by the folding of an RNA domain
Authors: Mortimer Stefanie A. , Weeks Kevin M.
Published: August 2009

A striking and widespread observation is that higher-order folding for many RNAs is very slow, often requiring minutes. In some cases, slow folding reflects the need to disrupt stable, but incorrect, interactions. However, a molecular explanation for slow folding in most RNAs is unknown. The specificity domain of the
Bacillus subtilis
RNase P ribozyme undergoes a rate-limiting folding step on the minute time-scale. This RNA also contains a C2′-endo nucleotide at A130 that exhibits extremely slow local conformational dynamics. This nucleotide is evolutionarily conserved and essential for tRNA recognition by RNase P. Here we show that deleting this single nucleotide accelerates folding by an order of magnitude even though this mutation does not change the global fold of the RNA. These results demonstrate that formation of a single stacking interaction at a C2′-endo nucleotide comprises the rate-determining step for folding an entire 154 nucleotide RNA. C2′-endo nucleotides exhibit slow local dynamics in structures spanning isolated helices to complex tertiary interactions. Because the motif is both simple and ubiquitous, C2′-endo nucleotides may function as molecular timers in many RNA folding and ligand recognition reactions.
Genome-wide functional analysis reveals that infection-associated fungal autophagy is necessary for rice blast disease
Authors: Kershaw Michael J. , Talbot Nicholas J.
Published: August 2009

To cause rice blast disease, the fungus
Magnaporthe oryzae
elaborates specialized infection structures called appressoria, which use enormous turgor to rupture the tough outer cuticle of a rice leaf. Here, we report the generation of a set of 22 isogenic
M. oryzae
mutants each differing by a single component of the predicted autophagic machinery of the fungus. Analysis of this set of targeted deletion mutants demonstrated that loss of any of the 16 genes necessary for nonselective macroautophagy renders the fungus unable to cause rice blast disease, due to impairment of both conidial programmed cell death and appressorium maturation. In contrast, genes necessary only for selective forms of autophagy, such as pexophagy and mitophagy, are dispensable for appressorium-mediated plant infection. A genome-wide analysis therefore demonstrates the importance of infection-associated, nonselective autophagy for the establishment of rice blast disease.
A common MECP2 haplotype associates with reduced cortical surface area in humans in two independent populations
Authors: Joyner Alexander H. , J. Cooper Roddey , Bloss Cinnamon S. , Bakken Trygve E. , Rimol Lars M. , Melle Ingrid , Agartz Ingrid , Djurovic Srdjan , Topol Eric J. , Schork Nicholas J. , Andreassen Ole A. , Dale Anders M.
Published: August 2009

The gene MECP2 is a well-known determinant of brain structure. Mutations in the MECP2 protein cause microencephalopathy and are associated with several neurodevelopmental disorders that affect both brain morphology and cognition. Although mutations in MECP2 result in severe neurological phenotypes, the effect of common variation in this genetic region is unknown. We find that common sequence variations in a region in and around
MECP2
show association with structural brain size measures in 2 independent cohorts, a discovery sample from the Thematic Organized Psychosis research group, and a replication sample from the Alzheimer's Disease Neuroimaging Initiative. The most statistically significant replicated association (
P
< 0.025 in both cohorts) involved the minor allele of SNP rs2239464 with reduced cortical surface area, and the finding was specific to male gender in both populations. Variations in the
MECP2
region were associated with cortical surface area but not cortical thickness. Secondary analysis showed that this allele was also associated with reduced surface area in specific cortical regions (cuneus, fusiform gyrus, pars triangularis) in both populations.
MSC p43 required for axonal development in motor neurons
Authors: Zhu Xiaodong , Liu Yang , Yin Yanqing , Shao Aiyun , Zhang Bo , Kim Sunghoon , Zhou Jiawei
Published: August 2009

Neuron connectivity and correct neural function largely depend on axonal integrity. Neurofilaments (NFs) constitute the main cytoskeletal network maintaining the structural integrity of neurons and exhibit dynamic changes during axonal and dendritic growth. However, the mechanisms underlying axonal development and maintenance remain poorly understood. Here, we identify that multisynthetase complex p43 (MSC p43) is essential for NF assembly and axon maintenance. The MSC p43 protein was predominantly expressed in central neurons and interacted with NF light subunit in vivo. Mice lacking MSC p43 exhibited axon degeneration in motor neurons, defective neuromuscular junctions, muscular atrophy, and motor dysfunction. Furthermore, MSC p43 depletion in mice caused disorganization of the axonal NF network. Mechanistically, MSC p43 is required for maintaining normal phosphorylation levels of NFs. Thus, MSC p43 is indispensable in maintaining axonal integrity. Its dysfunction may underlie the NF disorganization and axon degeneration associated with motor neuron degenerative diseases.
Spontaneous cortical activity in awake monkeys composed of neuronal avalanches
Authors: Petermann Thomas , Thiagarajan Tara C. , Lebedev Mikhail A. , Nicolelis Miguel A. L. , Chialvo Dante R. , Plenz Dietmar
Published: August 2009

Spontaneous neuronal activity is an important property of the cerebral cortex but its spatiotemporal organization and dynamical framework remain poorly understood. Studies in reduced systems—tissue cultures, acute slices, and anesthetized rats—show that spontaneous activity forms characteristic clusters in space and time, called neuronal avalanches. Modeling studies suggest that networks with this property are poised at a critical state that optimizes input processing, information storage, and transfer, but the relevance of avalanches for fully functional cerebral systems has been controversial. Here we show that ongoing cortical synchronization in awake rhesus monkeys carries the signature of neuronal avalanches. Negative LFP deflections (nLFPs) correlate with neuronal spiking and increase in amplitude with increases in local population spike rate and synchrony. These nLFPs form neuronal avalanches that are scale-invariant in space and time and with respect to the threshold of nLFP detection. This dimension, threshold invariance, describes a fractal organization: smaller nLFPs are embedded in clusters of larger ones without destroying the spatial and temporal scale-invariance of the dynamics. These findings suggest an organization of ongoing cortical synchronization that is scale-invariant in its three fundamental dimensions—time, space, and local neuronal group size. Such scale-invariance has ontogenetic and phylogenetic implications because it allows large increases in network capacity without a fundamental reorganization of the system.
ATP-dependent mechanics of red blood cells
Authors: Betz Timo , Lenz Martin , Joanny Jean-François , Sykes Cécile
Published: August 2009

Red blood cells are amazingly deformable structures able to recover their initial shape even after large deformations as when passing through tight blood capillaries. The reason for this exceptional property is found in the composition of the membrane and the membrane-cytoskeleton interaction. We investigate the mechanics and the dynamics of RBCs by a unique noninvasive technique, using weak optical tweezers to measure membrane fluctuation amplitudes with μs temporal and sub nm spatial resolution. This enhanced edge detection method allows to span over >4 orders of magnitude in frequency. Hence, we can simultaneously measure red blood cell membrane mechanical properties such as bending modulus κ = 2.8 ± 0.3 × 10
−19
J = 67.6 ± 7.2
k
B
T
, tension σ = 6.5 ± 2.1 × 10
−7
N/m, and an effective viscosity η
eff
= 81 ± 3.7 × 10
−3
Pa s that suggests unknown dissipative processes. We furthermore show that cell mechanics highly depends on the membrane-spectrin interaction mediated by the phosphorylation of the interconnection protein 4.1R. Inhibition and activation of this phosphorylation significantly affects tension and effective viscosity. Our results show that on short time scales (slower than 100 ms) the membrane fluctuates as in thermodynamic equilibrium. At time scales longer than 100 ms, the equilibrium description breaks down and fluctuation amplitudes are higher by 40% than predicted by the membrane equilibrium theory. Possible explanations for this discrepancy are influences of the spectrin that is not included in the membrane theory or nonequilibrium fluctuations that can be accounted for by defining a nonthermal effective energy of up to
E
eff
= 1.4 ± 0.1 k
B
T
, that corresponds to an actively increased effective temperature.
Specific ER quality control components required for biogenesis of the plant innate immune receptor EFR
Authors: Li Jing , Zhao-Hui Chu , Batoux Martine , Nekrasov Vladimir , Roux Milena , Chinchilla Delphine , Zipfel Cyril , Jones Jonathan D. G.
Published: August 2009

Plant innate immunity depends in part on recognition of pathogen-associated molecular patterns (PAMPs), such as bacterial flagellin, EF-Tu, and fungal chitin. Recognition is mediated by pattern-recogntition receptors (PRRs) and results in PAMP-triggered immunity. EF-Tu and flagellin, and the derived peptides elf18 and flg22, are recognized in
Arabidopsis
by the leucine-rich repeat receptor kinases (LRR-RK), EFR and FLS2, respectively. To gain insights into the molecular mechanisms underlying PTI, we investigated EFR-mediated PTI using genetics. A forward-genetic screen for
Arabidopsis
elf18-insensitive (
elfin
) mutants revealed multiple alleles of calreticulin3 (
CRT3
), UDP-glucose glycoprotein glucosyl transferase (
UGGT
), and an HDEL receptor family member (ERD2b), potentially involved in endoplasmic reticulum quality control (ER-QC). Strikingly, FLS2-mediated responses were not impaired in
crt3
,
uggt
, and
erd2b
null mutants, revealing that the identified mutations are specific to EFR. A
crt3
null mutant did not accumulate EFR protein, suggesting that EFR is a substrate for CRT3. Interestingly,
Erd2b
did not accumulate CRT3 protein, although they accumulate wild-type levels of other ER proteins. ERD2B seems therefore to be a specific HDEL receptor for CRT3 that allows its retro-translocation from the Golgi to the ER. These data reveal a previously unsuspected role of a specific subset of ER-QC machinery components for PRR accumulation in plant innate immunity.
Lack of TNFα expression protects anaplastic lymphoma kinase-positive T-cell lymphoma (ALK+ TCL) cells from apoptosis
Authors: Zhang Qian , Wang Hong Y. , Bhutani Gauri , Liu Xiaobin , Paessler Michele , Tobias John W. , Baldwin Donald , Swaminathan Kunchithapadam , Milone Michael C. , Wasik Mariusz A.
Published: August 2009

Here we report that T-cell lymphomas characterized by the expression of anaplastic lymphoma kinase (ALK+ TCL) fail to express the TNFα and frequently display DNA methylation of the TNFα gene promoter. While only a subset of the ALK+ TCL-derived cell lines showed a high degree of the promoter methylation, all 6 showed low to nondetectable expression of the TNFα mRNA, and none expressed the TNFα protein. All 14 ALK+ TCL tissue samples examined displayed some degree of the TNFα promoter methylation, which was the most prominent in the distal portion of the the promoter. Treatment with a DNA methyltransferase inhibitor, 5′-aza-2′-deoxy-cytidine (5-ADC), reversed the promoter methylation and led to the expression of TNFα mRNA and protein. Furthermore, in vitro DNA methylation of the promoter impaired its transcriptional activity in the luciferase reporter assay. This impairment was seen even if only either distal or proximal portion were methylated, with methylation of the former exerting a more profound inhibitory effect. Notably, the ALK+ TCL cell lines uniformly expressed the type 1 TNFα receptor (TNF-R1) protein known to transduce the TNFα-induced pro-apoptotic signals. Moreover, exogeneous TNFα inhibited growth of the ALK+ TCL cell lines in a dose-dependent manner and induced activation of the members of the cell apoptotic pathway: Caspase 8 and caspase 3. These findings provide additional rationale for the therapeutic inhibition of DNA methyltransferases in ALK+ TCL. They also suggest that treatment with TNFα may be highly effective in this type of lymphoma.
Observation of a multiferroic critical end point
Authors: Kim Jae Wook , Haam S. Y. , Oh Y. S. , Park S. , Cheong S.-W. , Sharma P. A. , Jaime M. , Harrison N. , Han Jung Hoon , Jeon Gun-Sang , Coleman P. , Kim Kee Hoon
Published: August 2009

The study of abrupt increases in magnetization with magnetic field known as metamagnetic transitions has opened a rich vein of new physics in itinerant electron systems, including the discovery of quantum critical end points with a marked propensity to develop new kinds of order. However, the electric analogue of the metamagnetic critical end point, a “metaelectric” critical end point, has been rarely studied. Multiferroic materials wherein magnetism and ferroelectricity are cross-coupled are ideal candidates for the exploration of this novel possibility using magnetic-field (
H
) as a tuning parameter. Herein, we report the discovery of a magnetic-field-induced metaelectric transition in multiferroic BiMn
2
O
5
, in which the electric polarization (
P
) switches polarity along with a concomitant Mn spin–flop transition at a critical magnetic field
H
c
. The simultaneous metaelectric and spin–flop transitions become sharper upon cooling but remain a continuous cross-over even down to 0.5 K. Near the
P
= 0 line realized at μ
0
H
c
≈ 18
T
below 20 K, the dielectric constant (ɛ) increases significantly over wide field and temperature (
T
) ranges. Furthermore, a characteristic power-law behavior is found in the
P
(
H
) and ɛ(
H
) curves at
T
= 0.66 K. These findings indicate that a magnetic-field-induced metaelectric critical end point is realized in BiMn
2
O
5
near zero temperature.
Multiple feedback loops through cytokinin signaling control stem cell number within the
Arabidopsis
shoot meristem
Authors: Gordon Sean P. , Chickarmane Vijay S. , Ohno Carolyn , Meyerowitz Elliot M.
Published: August 2009

A central unanswered question in stem cell biology, both in plants and in animals, is how the spatial organization of stem cell niches are maintained as cells move through them. We address this question for the shoot apical meristem (SAM) which harbors pluripotent stem cells responsible for growth of above-ground tissues in flowering plants. We find that localized perception of the plant hormone cytokinin establishes a spatial domain in which cell fate is respecified through induction of the master regulator
WUSCHEL
as cells are displaced during growth. Cytokinin-induced
WUSCHEL
expression occurs through both CLAVATA-dependent and CLAVATA-independent pathways. Computational analysis shows that feedback between cytokinin response and genetic regulators predicts their relative patterning, which we confirm experimentally. Our results also may explain how increasing cytokinin concentration leads to the first steps in reestablishing the shoot stem cell niche in vitro.
Computer simulations predict that chromosome movements and rotations accelerate mitotic spindle assembly without compromising accuracy
Authors: Paul Raja , Wollman Roy , Silkworth William T. , Nardi Isaac K. , Cimini Daniela , Mogilner Alex
Published: August 2009

The mitotic spindle self-assembles in prometaphase by a combination of centrosomal pathway, in which dynamically unstable microtubules search in space until chromosomes are captured, and a chromosomal pathway, in which microtubules grow from chromosomes and focus to the spindle poles. Quantitative mechanistic understanding of how spindle assembly can be both fast and accurate is lacking. Specifically, it is unclear how, if at all, chromosome movements and combining the centrosomal and chromosomal pathways affect the assembly speed and accuracy. We used computer simulations and high-resolution microscopy to test plausible pathways of spindle assembly in realistic geometry. Our results suggest that an optimal combination of centrosomal and chromosomal pathways, spatially biased microtubule growth, and chromosome movements and rotations is needed to complete prometaphase in 10–20 min while keeping erroneous merotelic attachments down to a few percent. The simulations also provide kinetic constraints for alternative error correction mechanisms, shed light on the dual role of chromosome arm volume, and compare well with experimental data for bipolar and multipolar HT-29 colorectal cancer cells.
The reducible complexity of a mitochondrial molecular machine
Authors: Clements Abigail , Bursac Dejan , Gatsos Xenia , Perry Andrew J. , Civciristov Srgjan , Celik Nermin , Likic Vladimir A. , Poggio Sebastian , Jacobs-Wagner Christine , Strugnell Richard A. , Lithgow Trevor
Published: August 2009

Molecular machines drive essential biological processes, with the component parts of these machines each contributing a partial function or structural element. Mitochondria are organelles of eukaryotic cells, and depend for their biogenesis on a set of molecular machines for protein transport. How these molecular machines evolved is a fundamental question. Mitochondria were derived from an α-proteobacterial endosymbiont, and we identified in α-proteobacteria the component parts of a mitochondrial protein transport machine. In bacteria, the components are found in the inner membrane, topologically equivalent to the mitochondrial proteins. Although the bacterial proteins function in simple assemblies, relatively little mutation would be required to convert them to function as a protein transport machine. This analysis of protein transport provides a blueprint for the evolution of cellular machinery in general.
Mammalian
MagT1
and
TUSC3
are required for cellular magnesium uptake and vertebrate embryonic development
Authors: Zhou Hao , Clapham David E.
Published: August 2009

Magnesium (Mg
2+
) is the second most abundant cation in cells, yet relatively few mechanisms have been identified that regulate cellular levels of this ion. The most clearly identified Mg
2+
transporters are in bacteria and yeast. Here, we use a yeast complementary screen to identify two mammalian genes,
MagT1
and
TUSC3
, as major mechanisms of Mg
2+
influx.
MagT1
is universally expressed in all human tissues and its expression level is up-regulated in low extracellular Mg
2+
. Knockdown of either MagT1 or TUSC3 protein significantly lowers the total and free intracellular Mg
2+
concentrations in mammalian cell lines. Morpholino knockdown of MagT1 and TUSC3 protein expression in zebrafish embryos results in early developmental arrest; excess Mg
2+
or supplementation with mammalian mRNAs can rescue the effects. We conclude that
MagT1
and
TUSC3
are indispensable members of the vertebrate plasma membrane Mg
2+
transport system.
Biologic activity of irradiated, autologous, GM-CSF-secreting leukemia cell vaccines early after allogeneic stem cell transplantation
Authors: Ho Vincent T. , Vanneman Matthew , Kim Haesook , Sasada Tetsuro , Kang Yoon Joong , Pasek Mildred , Cutler Corey , Koreth John , Alyea Edwin , Sarantopoulos Stefanie , Antin Joseph H. , Ritz Jerome , Canning Christine , Kutok Jeffery , Mihm Martin C. , Dranoff Glenn , Soiffer Robert
Published: August 2009

Through an immune-mediated graft-versus-leukemia effect, allogeneic hematopoietic stem cell transplantation (HSCT) affords durable clinical benefits for many patients with hematologic malignancies. Nonetheless, subjects with high-risk acute myeloid leukemia or advanced myelodysplasia often relapse, underscoring the need to intensify tumor immunity within this cohort. In preclinical models, allogeneic HSCT followed by vaccination with irradiated tumor cells engineered to secrete GM-CSF generates a potent antitumor effect without exacerbating the toxicities of graft-versus-host disease (GVHD). To test whether this strategy might be similarly active in humans, we conducted a Phase I clinical trial in which high-risk acute myeloid leukemia or myelodysplasia patients were immunized with irradiated, autologous, GM-CSF-secreting tumor cells early after allogeneic, nonmyeloablative HSCT. Despite the administration of a calcineurin inhibitor as prophylaxis against GVHD, vaccination elicited local and systemic reactions that were qualitatively similar to those previously observed in nontransplanted, immunized solid-tumor patients. While the frequencies of acute and chronic GVHD were not increased, 9 of 10 subjects who completed vaccination achieved durable complete remissions, with a median follow-up of 26 months (range 12–43 months). Six long-term responders showed marked decreases in the levels of soluble NKG2D ligands, and 3 demonstrated normalization of cytotoxic lymphocyte NKG2D expression as a function of treatment. Together, these results establish the safety and immunogenicity of irradiated, autologous, GM-CSF-secreting leukemia cell vaccines early after allogeneic HSCT, and raise the possibility that this combinatorial immunotherapy might potentiate graft-versus-leukemia in patients.
Book Reviews
Authors: Heilo Arne
Published: August 2009

Thyroid Ultrasound and Ultrasound-Guided FNA. Second edition. Edited by H. J. Baskin, D. S. Duick, & R. A. Levine. Heidelberg: Springer Verlag, 2008. 264 pages, 150 figures. ISBN: 978-0-387-77633-0. Price (paperback): USD 59.95, EUR 46.95
Effectiveness of Routine Patient Cleansing with Chlorhexidine Gluconate for Infection Prevention in the Medical Intensive Care Unit
Authors: Popovich Kyle J. , Hota Bala , Hayes Robert , Weinstein Robert A. , Hayden Mary K.
Published: August 2009

Background.

Controlled studies that took place in medical intensive care units (MICUs) have demonstrated that bathing patients with Chlorhexidine gluconate (CHG) can reduce skin colonization with potential pathogens and can lessen the risk of central venous catheter (CVC)-associated bloodstream infection (BSI).

Objective.

TO examine, without oversight of practice by research study staff, the effectiveness or real-world effect of patient cleansing with CHG on rates of CVC-associated BSI.

Design.

In the fall of 2005, the MICU at Rush University Medical Center discontinued bathing patients daily with soap and water and substituted skin cleansing with no-rinse, 2% CHG-impregnated cloths. This change was a clinical management decision without research input.

Setting.

A 21-bed MICU at Rush University Medical Center.

Patients.

Patients hospitalized in the MICU during the period from September 2004 through October 2006.

Methods.

In a pre-post study design, we gathered data from administrative and laboratory databases, infection control practitioner logs, and patient medical charts to compare rates of CVC-associated BSI and blood culture contamination between the baseline soap-and-water bathing period (September 2004-October 2005) and the CHG bathing period (November 2005-October 2006). Rates of secondary BSI,Clostridium difficileinfection (CDI), ventilator-associated pneumonia (VAP), and urinary tract infection (UTI) served as control variables that were not expected to be affected by CHG bathing.

Results.

Bathing with CHG was associated with a statistically significant decrease in the rate of CVC-associated BSI (from 5.31 to 0.69 cases per 1,000 CVC-days;P= .006) and in the rate of blood culture contamination (from 6.99 to 4.1 cases per 1,000 patient-days;P= .04). Rates of secondary BSI, CDI, VAP, and UTI did not change significantly.

Conclusions.

In our analysis of real-world practice, daily bathing of MICU patients with CHG was effective at reducing rates of CVC-associated BSI and blood culture contamination. Controlled studies are needed to determine whether these beneficial effects extend outside the MICU.
On spun-normal and twisted squares surfaces
Authors: Segerman Henry
Published: August 2009

Given a 3 manifold

M
M

with torus boundary and an ideal triangulation, Yoshida and Tillmann give different methods to construct surfaces embedded in

M
M

from ideal points of the deformation variety. Yoshida builds a surface from twisted squares, whereas Tillmann produces a spun-normal surface. We investigate the relation between the generated surfaces and extend a result of Tillmann’s (that if the ideal point of the deformation variety corresponds to an ideal point of the character variety, then the generated spun-normal surface is detected by the character variety) to the generated twisted squares surfaces.
A new interpolation formula for the Titchmarsh-Weyl 𝑚-function
Authors: Rybkin Alexei , Tuan Vu
Published: August 2009

For the Titchmarsh-Weyl

m
m

-function of the half-line Schrödinger operator with Dirichlet boundary conditions we put forward a new interpolation formula which allows one to reconstruct the

m
m

-function from its values on a certain infinite set of points for a broad class of potentials.
A Kurosh-type theorem for type III factors
Authors: Asher Jason
Published: August 2009

We prove a generalization of N. Ozawa’s Kurosh-type theorem to the setting of free products of semiexact

II
1

\text {II}_1

factors with respect to arbitrary (non-tracial) faithful normal states. We are thus able to distinguish certain resulting type III factors. For example, if

M
=
L

F
n

⊗
L

F
m

M = LF_n \otimes LF_m

and

{

φ
i

}

\{\varphi _i\}

is any sequence of faithful normal states on

M
M

, then the

l
l

-various

(
M
,

φ
1

)
∗
.
.
.
∗
(
M
,

φ
l

)

(M,\varphi _1) * ... * (M,\varphi _l)

are all mutually non-isomorphic.
Recursive formula for 𝜓^{𝑔}-𝜆₁𝜓^{𝑔-1}+⋯+(-1)^{𝑔}𝜆_{𝑔} in \overline{ℳ}_{ℊ,1}
Authors: Arcara D. , Sato F.
Published: August 2009

Mumford proved that

ψ
g

−

λ
1

ψ

g
−
1

+
⋯
+
(
−
1

)
g

λ
g

=
0

\psi ^g-\lambda _1\psi ^{g-1}+\cdots +(-1)^g\lambda _g=0

in the Chow ring of

M

¯

g
,
1

\overline {\mathcal {M}}_{g,1}

. We find an explicit recursive formula for

ψ
g

−

λ
1

ψ

g
−
1

+
⋯
+
(
−
1

)
g

λ
g

\psi ^g-\lambda _1\psi ^{g-1}+\cdots + (-1)^g\lambda _g

in the tautological ring of

M

¯

g
,
1

\overline {\mathcal {M}} _{g,1}

as a combination of classes supported on boundary strata.
On the divisibility of the class number of imaginary quadratic number fields
Authors: Louboutin Stéphane
Published: August 2009

We prove that if at least one of the prime divisors of an odd integer

U
≥
3

U\geq 3

is equal to

3
3

mod

4
4

, then the ideal class group of the imaginary quadratic field

Q

(

1
−
4

U
n

)

\mathbf {Q}(\sqrt {1-4U^n})

contains an element of order

n
n

.
On traces of Sobolev functions on the boundary of extension domains
Authors: Biegert Markus
Published: August 2009

Assume that

Ω
⊂

R

N

\Omega \subset \mathbb {R}^N

is a bounded

W

1
,
p

W^{1,p}

-extension domain and that

μ
\mu

is an upper

d
d

-Ahlfors measure on

∂
Ω

\partial \Omega

with

p
∈
(
1
,
N
)

p\in (1,N)

and

d
∈
(
N
−
p
,
N
)

d\in (N-p,N)

. Then there exist continuous trace operators from

W

1
,
p

(
Ω
)

W^{1,p}(\Omega )

into

L
q

(
∂
Ω
,
d
μ
)

L^q(\partial \Omega ,d\mu )

and into

B
β
p

(
∂
Ω
,
d
μ
)

B^p_\beta (\partial \Omega ,d\mu )

for every

q
∈
[
1
,
d
p

/

(
N
−
p
)
]

q\in [1,dp/(N-p)]

and every

β
∈
(
0
,
1
−
(
N
−
d
)

/

p
]

\beta \in (0,1-(N-d)/p]

.
A proof of Bochner’s tube theorem
Authors: Hounie J.
Published: August 2009

We give a proof of Bochner’s tube theorem based on the Baouendi-Treves approximation formula.
On quasi-metric and metric spaces
Authors: Paluszyński Maciej , Stempak Krzysztof
Published: August 2009

Given a space

X
X

with a quasi-metric

ρ
\rho

it is known that the so-called

p
p

-chain approach can be used to produce a metric in

X
X

equivalent to

ρ
p

\rho ^p

for some

0
>
p
≤
1

0>p\le 1

, hence also a quasi-metric

ρ
~

\tilde {\rho }

equivalent to

ρ
\rho

with better properties. We refine this result and obtain an exponent

p
p

which is, in general, optimal.
Prohibitin Inhibits Tumor Necrosis Factor alpha–induced Nuclear Factor-kappa B Nuclear Translocation via the Novel Mechanism of Decreasing Importin α3 Expression
Authors: Theiss Arianne L. , Jenkins Aaron K. , Okoro Ngozi I. , Klapproth Jan-Michael A. , Merlin Didier , Sitaraman Shanthi V.
Published: August 2009

Expression of prohibitin 1 (PHB), a multifunctional protein in the cell, is decreased during inflammatory bowel disease (IBD). Little is known regarding the regulation and role of PHB during intestinal inflammation. We examined the effect of tumor necrosis factor alpha (TNF-α), a cytokine that plays a central role in the pathogenesis of IBD, on PHB expression and the effect of sustained PHB expression on TNF-α activation of nuclear factor-kappa B (NF-κB) and epithelial barrier dysfunction, two hallmarks of intestinal inflammation. We show that TNF-α decreased PHB protein and mRNA abundance in intestinal epithelial cells in vitro and in colon mucosa in vivo. Sustained expression of prohibitin in intestinal epithelial cells in vitro and in vivo (prohibitin transgenic mice, PHB TG) resulted in a marked decrease in TNF-α–induced nuclear translocation of the NF-κB protein p65, NF-κB/DNA binding, and NF-κB–mediated transcriptional activation despite robust IκB-α phosphorylation and degradation and increased cytosolic p65. Cells overexpressing PHB were protected from TNF-α–induced increased epithelial permeability. Expression of importin α3, a protein involved in p50/p65 nuclear import, was decreased in cells overexpressing PHB and in colon mucosa of PHB TG mice. Restoration of importin α3 levels sustained NF-κB activation by TNF-α during PHB transfection. These results suggest that PHB inhibits NF-κB nuclear translocation via a novel mechanism involving alteration of importin α3 levels. TNF-α decreases PHB expression in intestinal epithelial cells and restoration of PHB expression in these cells can protect against the deleterious effects of TNF-α and NF-κB on barrier function.
Mice Lacking Mannose 6-Phosphate Uncovering Enzyme Activity Have a Milder Phenotype than Mice Deficient forN-Acetylglucosamine-1-Phosphotransferase Activity
Authors: Boonen Marielle , Vogel Peter , Platt Kenneth A. , Dahms Nancy , Kornfeld Stuart
Published: August 2009

The mannose 6-phosphate (Man-6-P) lysosomal targeting signal on acid hydrolases is synthesized by the sequential action of uridine 5′-diphosphate-N-acetylglucosamine: lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) and GlcNAc-1-phosphodiester α-N-acetylglucosaminidase (“uncovering enzyme” or UCE). Mutations in the two genes that encode GlcNAc-1-phosphotransferase give rise to lysosomal storage diseases (mucolipidosis type II and III), whereas no pathological conditions have been associated with the loss of UCE activity. To analyze the consequences of UCE deficiency, the UCE gene was inactivated via insertional mutagenesis in mice. The UCE −/− mice were viable, grew normally and lacked detectable histologic abnormalities. However, the plasma levels of six acid hydrolases were elevated 1.6- to 5.4-fold over wild-type levels. These values underestimate the degree of hydrolase hypersecretion as these enzymes were rapidly cleared from the plasma by the mannose receptor. The secreted hydrolases contained GlcNAc-P-Man diesters, exhibited a decreased affinity for the cation-independent mannose 6-phosphate receptor and failed to bind to the cation-dependent mannose 6-phosphate receptor. These data demonstrate that UCE accounts for all the uncovering activity in the Golgi. We propose that in the absence of UCE, the weak binding of the acid hydrolases to the cation-independent mannose 6-phosphate receptor allows sufficient sorting to lysosomes to prevent the tissue abnormalities seen with GlcNAc-1-phosphotranferase deficiency.
Distress prevention by grooming others in crested black macaques
Authors: Aureli Filippo , Yates Kerrie
Published: August 2009

Allogrooming is probably one of the most common and most studied social behaviours in a variety of animals. Whereas the short-term benefits for the groomee have often been investigated, little is known about the effects for the groomer. Our study focused on the short-term effects of grooming another group member in seven adult female crested black macaques (
Macaca nigra
). We found reductions in self-directed behaviour, an indicator of anxiety, and aggressive tendencies soon after grooming, when compared to matched-control periods. These findings can be interpreted as evidence of distress prevention, possibly mediated by an increase in tolerance. Indeed, a former groomee was more likely to be the nearest neighbour of the former groomer in the 10 min after grooming ended. Thus, the role of grooming in short-term distress alleviation can be applicable to the groomer as well as the groomee. These short-term effects, together with the longer-term effects of large and/or strong grooming networks confirm that grooming, as well as receiving grooming, has great importance for social dynamics.
Amplification of local chirality within a folded dendrimer. An intramolecular ‘sergeants and soldiers’ experiment
Authors: Hofacker Amanda L. , Parquette Jon R.
Published: August 2009

A series of pyridine-2,6-dicarboxamide dendrons having varying proportions of chiral and achiral termini have been prepared. Circular dichroism and X-ray crystallographic studies indicate that these folded dendrons propagate terminal chirality via a ‘sergeants and soldiers’ process. The extent of chiral amplification shows a dependence on dendron generation, but also is affected by the relative positioning of the chiral termini at the periphery of the dendron. Analysis of the crystal structures of the G1 dendrons,
4a
–
6a
, reveals chain–chain and chain–dendron conformational communication, which is likely to be responsible for the chiral amplification observed in solution.
On the collapse of locally isostatic networks
Authors: Kapko V. , Treacy M. M. J. , Thorpe M. F. , Guest S. D.
Published: August 2009

We examine the flexibility of periodic planar networks built from rigid corner-connected equilateral triangles. Such systems are locally isostatic, since for each triangle the total number of degrees of freedom equals the total number of constraints. These nets are two-dimensional analogues of zeolite frameworks, which are periodic assemblies of corner-sharing tetrahedra. If the corner connections are permitted to rotate, as if pin-jointed, there is always at least one collapse mechanism in two dimensions (and at least three mechanisms in three dimensions). We present a number of examples of such collapse modes for different topologies of triangular net. We show that the number of collapse mechanisms grows with the size of unit cell. The collapsible mechanisms that preserve higher symmetry of the network tend to exhibit the widest range of densities without sterical overlap.
Genetic diversity and connectivity in a brooding reef coral at the limit of its distribution
Authors: Noreen Annika M. E. , Harrison Peter L. , Van Oppen Madeleine J. H.
Published: August 2009

Remote populations are predicted to be vulnerable owing to their isolation from potential source reefs, and usually low population size and associated increased extinction risk. We investigated genetic diversity, population subdivision and connectivity in the brooding reef coralSeriatopora hystrixat the limits of its Eastern Australian (EA) distribution and three sites in the southern Great Barrier Reef (GBR). Over the approximately 1270 km survey range, high levels of population subdivision were detected (globalFST= 0.224), with the greatest range in pairwiseFSTvalues observed among the three southernmost locations: Lord Howe Island, Elizabeth Reef and Middleton Reef. Flinders Reef, located between the GBR and the more southerly offshore reefs, was highly isolated and showed the signature of a recent bottleneck. High pairwiseFSTvalues and the presence of multiple genetic clusters indicate that EA subtropical coral populations have been historically isolated from each other and the GBR. One putative first-generation migrant was detected from the GBR into the EA subtropics. Occasional long-distance dispersal is supported by changes in species composition at these high-latitude reefs and the occurrence of new species records over the past three decades. While subtropical populations exhibited significantly lower allelic richness than their GBR counterparts, genetic diversity was still moderately high. Furthermore, subtropical populations were not inbred and had a considerable number of private alleles. The results suggest that these high-latitudeS. hystrixpopulations are supplemented by infrequent long-distance migrants from the GBR and may have adequate population sizes to maintain viability and resist severe losses of genetic diversity.
Termites eavesdrop to avoid competitors
Authors: Evans Theodore A. , Inta Ra , Lai Joseph C. S. , Prueger Stefan , Foo Nyuk Wei , Fu Eugene Wei'en , Lenz Michael
Published: August 2009

Competition exclusion, when a single species dominates resources due to superior competitiveness, is seldom observed in nature. Termites compete for resources with deadly consequences, yet more than one species can be found feeding in the same wooden resource. This is especially surprising when drywood species, with colonies of a few hundred, are found cohabiting with subterranean species, with colonies of millions. Termites communicate vibro-acoustically and, as these signals can travel over long distances, they are vulnerable to eavesdropping. We investigated whether drywood termites could eavesdrop on vibration cues from subterranean species. We show, using choice experiments and recordings, that the drywood termiteCryptotermes secunduscan distinguish its own species from the dominant competitor in the environment, the subterranean termiteCoptotermes acinaciformis. The drywood termite was attracted to its own vibration cues, but was repelled by those of the subterranean species. This response increased with decreasing wood size, corresponding with both increased risk and strength of the cue. The drywood termites appear to avoid confrontation by eavesdropping on the subterranean termites; these results provide further evidence that vibro-acoustic cues are important for termite sensory perception and communication.
Leptin increases maternal investment
Authors: French Susannah S. , Greives Timothy J. , Zysling Devin A. , Chester Emily M. , Demas Gregory E.
Published: August 2009

The primary goal of virtually all organisms is to produce genetic offspring, thereby passing on their genes to future generations. Offspring production, however, is limited by available resources within an environment. Moreover, distributing sufficient energy among competing physiological systems is challenging and can result in trade-offs between self-maintenance and offspring investment when resources are limited. In the current study, we tested the hypothesis that the adipose hormone leptin is involved in mediating energetic trade-offs between competing physiological systems. Specifically, we tested the effects of elevated maternal leptin on investment into offspring production versus self maintenance (immune function), in the Siberian hamster (
Phodopus sungorus
). The current study provides the first evidence that leptin serves as a signal to mothers of available energy resulting in epigenetic effects. Therefore, elevated leptin allows females to retain more embryos to parturition, and rear more offspring to weaning via reduced maternal infanticide. Innate immune response was suppressed seemingly as a result of these enlarged litters, suggesting that the observed fitness increase is not without costs to the mother. Collectively, these findings suggest that leptin plays a critical role in allowing mothers to determine how much energy to invest in the production and care of young versus self-maintenance.
Reproductive compensation favours male-killingWolbachiain a live-bearing host
Authors: Koop Julie L. , Zeh David W. , Bonilla Melvin M. , Zeh Jeanne A.
Published: August 2009

Wolbachiaare maternally inherited, cellular endosymbionts that can enhance their fitness by biasing host sex ratio in favour of females. Male killing (MK) is an extreme form of sex-ratio manipulation that is selectively advantageous if the self-sacrifice ofWolbachiain males increases transmission through females. In live-bearing hosts, females typically produce more embryos than can be carried to term, and reproductive compensation through maternal resource reallocation from dead males to female embryos could increase the number of daughters born to infected females. Here, we report a new strain of MKWolbachia(wCsc2) in the pseudoscorpion,Cordylochernes scorpioides, and present the first empirical evidence that reproductive compensation favours the killing of males in a viviparous host. Females infected with thewCsc2 strain produced 26 per cent more and significantly larger daughters than tetracycline-cured females. In contrast to the previously describedwCsc1 MKWolbachiastrain inC. scorpioides,wCsc2 infection was not accompanied by an increase in the rate of spontaneous brood abortion. Characterization of thewCsc1 andwCsc2 strains by multi-locus sequence typing and byWolbachiasurface protein (wsp) gene sequencing indicates that the marked divergence between these two MK strains in their impact on host reproductive success, and hence in their potential to spread, has occurred in association with homologous recombination in thewspgene.