bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of thickness, refractive index, and spectral scattering of an inhomogeneous thin film with rough interfaces
Authors: Pradeep J. Anto , Agarwal Pratima
Published: August 2010

The magnitude of spectral transmittance and reflectance is affected by the presence of inhomogeneity and interfacial roughness. Therefore, the methods, based on the magnitude of spectral transmittance and reflectance, are not adequate for the determination of thickness and optical constants of films with inhomogeneity and interfacial roughness. The present article proposes a method for the determination of thickness and refractive index using only the positions of the interference fringes in spectral transmittance and reflectance at two different angles of incidence. The proposed method is verified through numerical simulations, which result in <1% error for the film thickness. The complete parametrical dependence of spectral transmittance and reflectance of inhomogeneous film with rough interfaces on a substrate have been worked out for the film on transparent and opaque substrates, respectively. The spectrum envelopes have been solved simultaneously and the mathematical formulae are given for the determination of spectral scattering due to inhomogeneity and interfacial roughness for both transmittance and reflectance cases.
High aspect ratio nanochannel machining using single shot femtosecond Bessel beams
Authors: Bhuyan M. K. , Courvoisier F. , Lacourt P. A. , Jacquot M. , Salut R. , Furfaro L. , Dudley J. M.
Published: August 2010

We report high aspect ratio nanochannel fabrication in glass using single-shot femtosecond Bessel beams of sub-3 μJ pulse energies at 800 nm. We obtain near-parallel nanochannels with diameters in the range 200–800 nm, and aspect ratios that can exceed 100. An array of 230 nm diameter channels with 1.6 μm pitch illustrates the reproducibility of this approach and the potential for writing periodic structures. We also report proof-of-principle machining of a through-channel of 400 nm diameter in a 43 μm thick membrane. These results represent a significant advance of femtosecond laser ablation technology into the nanometric regime.
Polarization sensitive lateral photoconductivity in GaAs/AlGaAs quantum well based structures on low-temperature grown GaAs(001)
Authors: Arora Ashish , Ghosh Sandip , Arora B. M. , Malzer Stefan , Döhler Gottfried
Published: August 2010

Polarization-resolved lateral-photoconductivity measurements are reported on device structures made of GaAs/Al0.3Ga0.7As quantum wells sandwiched between low-temperature grown GaAs(001) layers. The mesa device structures have long length (3 mm∥y) and narrow width (10 and 20 μm∥x) in the (001) plane. For light incident along [001], the ground state light-hole exciton transition is much stronger for light polarization E∥x, compared to E∥y. The heavy-hole exciton transition shows a weaker polarization anisotropy of opposite sign, being stronger for E∥y. Through calculations based on the Bir–Pikus Hamiltonian, the observed in-plane optical polarization anisotropy is shown to arise from valence band mixing induced by anisotropic strain in the plane of quantum wells.
Comparing modeling and measurements of the output power in chemical oxygen-iodine lasers: A stringent test of I2 dissociation mechanisms
Authors: Waichman K. , Barmashenko B. D. , Rosenwaks S.
Published: August 2010

A parametric study of the output power of supersonic chemical oxygen-iodine lasers (COILs) is carried out, applying a kinetic-fluid dynamics model calculations as well as an analytical model and comparing the results to experimental studies. The I2 dissociation mechanism recently suggested by Azyazov et al. [J. Chem. Phys. 130, 104306 (2009)], which was previously used for comparison of model calculations to measurements of the small signal gain [K. Waichman et al., J. Appl. Phys. 106, 063108 (2009)], is applied here for a similar, but more sensitive, comparison of the laser output power. The dependence of the power on iodine flow rate and on mirror transmission is studied for low and high pressure COILs, respectively. Good agreement between the calculated and measured power is obtained for both low and high pressure COILs only when the processes suggested by Azyazov et al. are included in the calculations. This is different from the situation for the gain where for high pressure COILs, the calculated values were insensitive to the assumed dissociation mechanism, although for low pressure the measurements were reproduced only by applying the Azyazov et al. mechanism. We believe that the results of the present work strongly support the application of this mechanism for modeling the COIL operation.
Device characteristics of short-channel polymer field-effect transistors
Authors: Hirose Takeshi , Nagase Takashi , Kobayashi Takashi , Ueda Rieko , Otomo Akira , Naito Hiroyoshi
Published: August 2010

The influence of channel materials on the electrical characteristics of organic field-effect transistors (OFETs) with short-channel lengths ranging from 1 μm to 30 nm is investigated using polymer semiconductors. The current-voltage characteristics of short-channel OFETs strongly depend on the electrode/organic semiconductor contacts, and the parabolic output current due to space-charge limited current can be reduced by increasing the ionization potential of organic semiconductors. Transistor operations with a high on/off ratio over 103 are achieved in OFETs with 30 nm length channels.
Melting of Sn at high pressure: Comparisons with Pb
Authors: Schwager Beate , Ross Marvin , Japel Stefanie , Boehler Reinhard
Published: August 2010

Measurements for Sn, made using the laser-heated diamond cell, are reported that extend the melting curve to 68 GPa and 2300 K. Initially the melting temperature of Sn increases linearly with increasing pressure (dT/dP∼40 K/GPa) and near 38 GPa (2200 K) the melting curve flattens (dT/dP∼0), indicating a zero volume phase change at melting. The results are in good agreement with previously reported shock melting studies. In comparison to Sn the melting curve of Pb is relatively linear to 100 GPa, the highest pressure at which measurements have been made.
Selective electroless coating of palladium nanoparticles on metallic single-walled carbon nanotube
Authors: Feng Yiyu , Lv Peng , Zhang Xuequan , Li Yu , Feng Wei
Published: August 2010

The selective electroless coating of palladium (Pd) nanoparticles on metallic single-walled carbon nanotube (SWNT) was studied. The remarkable increase in conductivity of SWNT/Pd films up to fourfold higher than pure SWNT was due to p-type doping and Ohmic contact. Metallic behavior of SWNT/Pd-Field effect transistor (on/off ratio=1.2) was attributed to more hole carriers and no electrostatic barrier between nanotube and Pd. G-band and radial breathing mode in Raman indicates a definitive increase in the proportion of metallic SWNT. Results indicate Pd are selectively coated on metallic SWNT with more negative potential allowing for the electroless Pd2+ reduction.
The APC/C recruits cyclin B1–Cdk1–Cks in prometaphase before D box recognition to control mitotic exit
Authors: van Zon Wouter , Ogink Janneke , ter Riet Bas , Medema René H. , te Riele Hein , Wolthuis Rob M.F.
Published: August 2010

The ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C) is activated at prometaphase by mitotic phosphorylation and binding of its activator, Cdc20. This initiates cyclin A degradation, whereas cyclin B1 is stabilized by the spindle checkpoint. Upon checkpoint release, the RXXL destruction box (D box) was proposed to direct cyclin B1 to core APC/C or Cdc20. In this study, we report that endogenous cyclin B1–Cdk1 is recruited to checkpoint-inhibited, phosphorylated APC/C in prometaphase independently of Cdc20 or the cyclin B1 D box. Like cyclin A, cyclin B1 binds the APC/C by the Cdk cofactor Cks and the APC3 subunit. Prior binding to APC/CCdc20 makes cyclin B1 a better APC/C substrate in metaphase, driving mitotic exit and cytokinesis. We conclude that in prometaphase, the phosphorylated APC/C can recruit both cyclin A and cyclin B1 in a Cks-dependent manner. This suggests that the spindle checkpoint blocks D box recognition of APC/C-bound cyclin B1, whereas distinctive complexes between the N terminus of cyclin A and Cdc20 evade checkpoint control.
A chromatin-bound kinase, ERK8, protects genomic integrity by inhibiting HDM2-mediated degradation of the DNA clamp PCNA
Authors: Groehler Angela L. , Lannigan Deborah A.
Published: August 2010

Proliferating cell nuclear antigen (PCNA) acts as a scaffold, coordinator, and stimulator of numerous processes required for faithful transmission of genetic information. Maintaining PCNA levels above a critical threshold is essential, but little is known about PCNA protein turnover. We now show that ERK8 (extracellular signal-regulated kinase 8) is required for PCNA protein stability. ERK8 contains a conserved PCNA-interacting protein (PIP) box. Chromatin-bound ERK8 (ERK8CHROMATIN) interacts via this motif with PCNACHROMATIN, which acts as a platform for numerous proteins involved in DNA metabolism. Silencing ERK8 decreases PCNA levels and increases DNA damage. Ectopic expression of PCNA blocks DNA damage induced by ERK8 loss. ERK8 prevents HDM2-mediated PCNA destruction by inhibiting the association of PCNA with HDM2. This regulation is physiologically relevant as ERK8 activity is inhibited in transformed mammary cells. Our results reveal an unanticipated mechanism to control PCNA levels in normal cycling mammary epithelial cells and implicate ERK8 in the regulation of genomic stability.
Feedback amplification of fibrosis through matrix stiffening and COX-2 suppression
Authors: Liu Fei , Mih Justin D. , Shea Barry S. , Kho Alvin T. , Sharif Asma S. , Tager Andrew M. , Tschumperlin Daniel J.
Published: August 2010

Tissue stiffening is a hallmark of fibrotic disorders but has traditionally been regarded as an outcome of fibrosis, not a contributing factor to pathogenesis. In this study, we show that fibrosis induced by bleomycin injury in the murine lung locally increases median tissue stiffness sixfold relative to normal lung parenchyma. Across this pathophysiological stiffness range, cultured lung fibroblasts transition from a surprisingly quiescent state to progressive increases in proliferation and matrix synthesis, accompanied by coordinated decreases in matrix proteolytic gene expression. Increasing matrix stiffness strongly suppresses fibroblast expression of COX-2 (cyclooxygenase-2) and synthesis of prostaglandin E2 (PGE2), an autocrine inhibitor of fibrogenesis. Exogenous PGE2 or an agonist of the prostanoid EP2 receptor completely counteracts the proliferative and matrix synthetic effects caused by increased stiffness. Together, these results demonstrate a dominant role for normal tissue compliance, acting in part through autocrine PGE2, in maintaining fibroblast quiescence and reveal a feedback relationship between matrix stiffening, COX-2 suppression, and fibroblast activation that promotes and amplifies progressive fibrosis.
Cajal body surveillance of U snRNA export complex assembly
Authors: Suzuki Tatsuya , Izumi Hiroto , Ohno Mutsuhito
Published: August 2010

Phosphorylated adaptor for RNA export (PHAX) is the key export mediator for spliceosomal U small nuclear RNA (snRNA) precursors in metazoa. PHAX is enriched in Cajal bodies (CBs), nuclear subdomains involved in the biogenesis of small ribonucleoproteins. However, CBs’ role in U snRNA export has not been demonstrated. In this study, we show that U snRNA precursors microinjected into Xenopus laevis oocyte nuclei temporarily concentrate in CBs but gradually decrease as RNA export proceeds. Inhibition of PHAX activity by the coinjection of a specific anti-PHAX antibody or a dominant-negative PHAX mutant inhibits U snRNA export and simultaneously enhances accumulation of U snRNA precursors in CBs, indicating that U snRNAs transit through CBs before export and that binding to PHAX is required for efficient exit of U snRNAs from CBs. Similar results were obtained with U snRNAs transcribed from microinjected genes. These results reveal a novel function for CBs, which ensure that U snRNA precursors are properly bound by PHAX.
Structure of hibernating ribosomes studied by cryoelectron tomography in vitro and in situ
Authors: Ortiz Julio O. , Brandt Florian , Matias Valério R.F. , Sennels Lau , Rappsilber Juri , Scheres Sjors H.W. , Eibauer Matthias , Hartl F. Ulrich , Baumeister Wolfgang
Published: August 2010

Ribosomes arranged in pairs (100S) have been related with nutritional stress response and are believed to represent a “hibernation state.” Several proteins have been identified that are associated with 100S ribosomes but their spatial organization has hitherto not been characterized. We have used cryoelectron tomography to reveal the three-dimensional configuration of 100S ribosomes isolated from starved Escherichia coli cells and we have described their mode of interaction. In situ studies with intact E. coli cells allowed us to demonstrate that 100S ribosomes do exist in vivo and represent an easily reversible state of quiescence; they readily vanish when the growth medium is replenished.
Impact of an Assay That Enables Rapid Determination of Staphylococcus Species and Their Drug Susceptibility on the Treatment of Patients with Positive Blood Culture Results
Authors: Parta Mark , Goebel Melanie , Thomas Jimmy , Matloobi Mahsa , Stager Charles , Musher Daniel M.
Published: August 2010

Objective.

To determine whether an earlier determination of staphylococcal species and their antibiotic susceptibility decreases unnecessary antistaphylococcal treatment and/or facilitates earlier appropriate treatment.

Methods.

We used the Xpert MRSA/SA BC system (Cepheid) for immediate determination of species and their drug susceptibility in patients whose blood cultures revealed gram-positive cocci in clusters. We compared the treatment of patients whose physicians received early notification of these results (group 1) with the treatment of patients in a historical cohort with delayed reporting after traditional microbiological studies (group 2). Outcomes were analyzed according to whether blood culture was positive for Staphylococcus species other than S. aureus, methicillin-susceptible S. aureus (MSSA), or methicillin-resistant S. aureus (MRSA) and whether the drugs used were appropriate for methicillin-susceptible or methicillin-resistant staphylococci (hereafter referred to as “MSS drug” or “MRS drug” therapy, respectively).

Results.

There were 44 (76%) of 58 patients with bacteremia due to Staphylococcus species other than S. aureus in group 1 and 58 (55%) of 106 patients with bacteremia due to Staphylococcus species other than S. aureus in group 2 who received no antistaphylococcal antibiotics (P <.01). Five (6%) of 89 patients in group 1 and 31 (25%) of 123 patients in group 2 received 0-168 hours (0-7 days) of MRS drug therapy (P < .01). Among patients with MSSA bacteremia, the mean time to initiation of appropriate therapy was 5.2 hours in group 1 and 49.8 hours in group 2 (P < = .007). Excluding patients who received MRS drug therapy for unrelated conditions, the mean duration of treatment was 19.7 hours in group 1 and 80.7 hours in group 2 (P = .003). Six (50%) of the 12 patients in group 1 and 39 (81%) of the 48 patients in group 2 received MRS drug therapy for MSSA bacteremia (P = .025). Time to initiation of therapy for MRSA bacteremia did not differ between groups.

Conclusions.

The use of an assay with rapid results reduced the use of antistaphylococcal therapy among patients who did not have S. aureus bacteremia; it also decreased the use of MRS drug therapy and led to earlier appropriate therapy among patients with MSSA bacteremia.
Facial Protective Equipment, Personnel, and Pandemics: Impact of the Pandemic (H1N1) 2009 Virus on Personnel and Use of Facial Protective Equipment
Authors: Murray Melanie , Grant Jennifer , Bryce Elizabeth , Chilton Paul , Forrester Leslie
Published: August 2010

Background.

Before the emergence of the pandemic (H1N1) 2009 virus, estimates of the stockpiles of facial protective equipment (FPE) and the impact that information had on personnel during a pandemic varied.

Objective.

To describe the impact of H1N1 on FPE use and hospital employee absenteeism.

Setting.

One tertiary care hospital and 2 community hospitals in the Vancouver Coastal Health (VCH) region, Vancouver, Canada.

Patients.

All persons with influenza-like illness admitted to the 3 VCH facilities during the period from June 28 through December 19, 2009.

Methods.

Data on patients and on FPE use were recorded prospectively. Data on salaried employee absenteeism were recorded during the period from August 1 through December 19, 2009.

Results.

During the study period, 865 patients with influenza-like illness were admitted to the 3 VCH facilities. Of these patients, 149 (17.2%) had laboratory-confirmed H1N1 influenza infection. The mean duration of hospital stay for these patients was 8.9 days, and the mean duration of intensive care unit stay was 9.2 days. A total of 134,281 masks and 173,145 N95 respirators (hereafter referred to as respirators) were used during the 24-week epidemic, double the weekly use of both items, compared with the previous influenza season. A ratio of 3 masks to 4 respirators was observed. Use of disposable eyewear doubled. Absenteeism mirrored the community epidemiologic curve, with a 260% increase in sick calls at the epidemic peak, compared with the nadir.

Conclusion.

Overall, FPE use more than doubled, compared with the previous influenza season, with respirator use exceeding literature estimates. A significant proportion of FPE resources were used while managing suspected cases. Planners should prepare for at least a doubling in mask and respirator use, and a 3.6-fold increase in staff sick calls.
Recovering singular integrals from Haar shifts
Authors: Vagharshakyan Armen
Published: August 2010

We recover one-dimensional Calderón-Zygmund convolution operators with sufficiently smooth kernels by means of a properly chosen averaging of certain dyadic shift operators. As a corollary, a sharp

A
2

A_2

inequality for these Calderón-Zygmund operators is derived from a corresponding inequality for dyadic shift operators.
The deficiency of a cohomology class
Authors: Morales C.
Published: August 2010

We define the deficiency of a cohomology class

u
u

with respect to a vector field as the set of limit points in the ambient manifold of long almost closed orbits representing homology classes on which

u
u

is nonpositive. We prove that, up to infinite cyclic coverings, the sole vector fields on closed manifolds exhibiting nonzero cohomology classes with finite deficiency are the gradient-like ones. We also prove that if the manifold is not a sphere, every singularity is hyperbolic and there is a closed transverse submanifold intersecting all regular orbits, then there is also a nonzero cohomology class with finite deficiency.
Complex equiangular Parseval frames and Seidel matrices containing 𝑝th roots of unity
Authors: Bodmann Bernhard , Elwood Helen
Published: August 2010

We derive necessary conditions for the existence of complex Seidel matrices containingppth roots of unity and having exactly two eigenvalues, under the assumption thatppis prime. The existence of such matrices is equivalent to the existence of equiangular Parseval frames with Gram matrices whose off-diagonal entries are a common multiple of theppth roots of unity. Explicitly examining the necessary conditions forp=5p=5andp=7p=7rules out the existence of many such frames with a number of vectors less than 50, similar to previous results in the cube roots case. On the other hand, we confirm the existence ofp2×p2p^2\times p^2Seidel matrices containingppth roots of unity, and thus the existence of the associated complex equiangular Parseval frames, for anyp≥2p\ge 2. The construction of these Seidel matrices also yields a family of previously unknown Butson-type complex Hadamard matrices.
A note on the gaps between consecutive zeros of the Riemann zeta-function
Authors: Bui H. , Milinovich M. , Ng N.
Published: August 2010

Assuming the Riemann Hypothesis, we show that infinitely often consecutive non-trivial zeros of the Riemann zeta-function differ by at most 0.5155 times the average spacing and that infinitely often they differ by at least 2.6950 times the average spacing.
How many Laplace transforms of probability measures are there?
Authors: Gao Fuchang , Li Wenbo , Wellner Jon A.
Published: August 2010

A bracketing metric entropy bound for the class of Laplace transforms of probability measures on

[
0
,
∞
)

[0,\infty )

is obtained through its connection with the small deviation probability of a smooth Gaussian process. Our results for the particular smooth Gaussian process seem to be of independent interest.
A mixed multiplicity formula for complete ideals in 2-dimensional rational singularities
Authors: Van Lierde Veronique
Published: August 2010

Let

(
R
,
m
)

(R,m)

be a 2-dimensional rational singularity with algebraically closed residue field and for which the associated graded ring is an integrally closed domain. We use the work of Göhner on condition

(
N
)

(N)

and the theory of degree functions developed by Rees and Sharp to give a very short and elementary proof of a formula for the (mixed) multiplicity of complete

m
m

-primary ideals in

(
R
,
m
)

(R,m)

.
Drinfeld modular forms modulo 𝔭
Authors: Vincent Christelle
Published: August 2010

The classical theory of “modular forms modulo

ℓ
\ell

” was developed by Serre and Swinnerton-Dyer in the early 1970’s. Their results revealed the important role that the quasi-modular form

E
2

E_2

, Ramanujan’s

Θ
\Theta

-operator, and the filtration of a modular form would subsequently play in applications of their theory. Here we obtain the analog of their results in the Drinfeld modular form setting.
Asymptotic properties of the residual bootstrap for Lasso estimators
Authors: Chatterjee A. , Lahiri S.
Published: August 2010

In this article, we derive the asymptotic distribution of the bootstrapped Lasso estimator of the regression parameter in a multiple linear regression model. It is shown that under some mild regularity conditions on the design vectors and the regularization parameter, the bootstrap approximation converges weakly to a random measure. The convergence result rigorously establishes a previously known heuristic formula for the limit distribution of the bootstrapped Lasso estimator. It is also shown that when one or more components of the regression parameter vector are zero, the bootstrap may fail to be consistent.
On robustness of exact controllability and exact observability under cross perturbations of the generator in Banach spaces
Authors: Mei Zhan-Dong , Peng Ji-Gen
Published: August 2010

This paper is concerned with the exact controllability and exact observability of linear systems in the Banach space setting. It is proved that both the admissibility of control operators and the admissibility of observation operators are invariant to cross perturbations of the generator of aC0C_0-semigroup. Moreover, under the admissibility invariance premise, the robustness of the exact controllability as well as the exact observability to such cross perturbations is verified. An illustrative example is presented.
Weighted Orlicz-Riesz capacity of balls
Authors: Mizuta Yoshihiro , Ohno Takao , Shimomura Tetsu
Published: August 2010

Our aim in this paper is to estimate the weighted Orlicz-Riesz capacity of balls.
Lower volume estimates and Sobolev inequalities
Authors: Pigola Stefano , Veronelli Giona
Published: August 2010

We consider complete manifolds with asymptotically non-negative curvature which enjoy a Euclidean-type Sobolev inequality and we get an explicit lower control on the volume of geodesic balls. In case the amount of negative curvature is small and the Sobolev constant is almost optimal, we deduce that the manifold is diffeomorphic to Euclidean space. This extends previous results by M. Ledoux and C. Xia.
Bivariate Lagrange interpolation at the Chebyshev nodes
Authors: Harris Lawrence
Published: August 2010

We discuss Lagrange interpolation on two sets of nodes in two dimensions where the coordinates of the nodes are Chebyshev points having either the same or opposite parity. We use a formula of Xu for Lagrange polynomials to obtain a general interpolation theorem for bivariate polynomials at either set of Chebyshev nodes. An extra term must be added to the interpolation formula to handle all polynomials with the same degree as the Lagrange polynomials. We express this term as a specifically determined linear combination of canonical polynomials that vanish on the set of Chebyshev nodes being considered.

As an application we deduce in an elementary way known minimal and near minimal cubature formulas applying to both the even and the odd Chebyshev nodes. Finally, we restrict to triangular subsets of the Chebyshev nodes to show unisolvence and deduce a Lagrange interpolation formula for bivariate symmetric and skew-symmetric polynomials. This result leads to another proof of the interpolation formula.
Szegő polynomials from hypergeometric functions
Authors: Ranga A.
Published: August 2010

Szegő polynomials with respect to the weight function

ω
(
θ
)
=

e

η
θ

[
sin
⁡
(
θ

/

2
)

]

2
λ

\omega (\theta ) = e^{\eta \theta } [\sin (\theta /2)]^{2\lambda }

, where

η
,
λ
∈

R

\eta , \lambda \in \mathbb {R}

and

λ
>
−
1

/

2

\lambda > -1/2

are considered. Many of the basic relations associated with these polynomials are given explicitly. Two sequences of para-orthogonal polynomials with explicit relations are also given.
The threshold function for vanishing of the top homology group of random 𝑑-complexes
Authors: Kozlov Dmitry
Published: August 2010

For positive integers

n
n

and

d
d

, and the probability function

0
≤
p
(
n
)
≤
1

0\leq p(n)\leq 1

, we let

Y

n
,
p
,
d

Y_{n,p,d}

denote the probability space of all at most

d
d

-dimensional simplicial complexes on

n
n

vertices, which contain the full

(
d
−
1
)

(d-1)

-dimensional skeleton, and whose

d
d

-simplices appear with probability

p
(
n
)

p(n)

. In this paper we determine the threshold function for vanishing of the top homology group in

Y

n
,
p
,
d

Y_{n,p,d}

, for all

d
≥
1

d\geq 1

.
On a class of finitary Lie algebras characterized through derivations
Authors: Brešar Matej , López Antonio
Published: August 2010

Let

L
L

be an infinite-dimensional simple Lie algebra over a field of characteristic

0
0

. Then there exist a derivation

d
d

on

L
L

and

n
≥
2

n\ge 2

such that

d
n

d^n

is a nonzero finite rank map if and only if

L
L

is finitary and contains a nonzero finite-dimensional abelian inner ideal. This is a partial statement of our main theorem. As auxiliary results needed for the proof we establish some properties of derivations in general nonassociative algebras.
Conservation in Function of a SCAR/WAVE Component During Infection Thread and Root Hair Growth in Medicago truncatula
Authors: Miyahara Akira , Richens Jennifer , Starker Colby , Morieri Giulia , Smith Lucinda , Long Sharon , Downie J. Allan , Oldroyd Giles E. D.
Published: August 2010

Nitrogen-fixing symbioses of plants are often associated with bacterially infected nodules where nitrogen fixation occurs. The plant host facilitates bacterial infection with the formation of infection threads, unique structures associated with these symbioses, which are invaginations of the host cell with the capability of traversing cellular junctions. Here, we show that the infection thread shares mechanistic similarities to polar-growing cells, because the required for infection thread (RIT) locus of Medicago truncatula has roles in root-hair, trichome, and infection-thread growth. We show that RIT encodes the M. truncatula ortholog of NAP1, a component of the SCAR/WAVE (suppressor of cAMP receptor/WASP-family verprolin homologous protein) complex that regulates actin polymerization, through the activation of ARP2/3. NAP1 of Arabidopsis thaliana functions equivalently to the M. truncatula gene, indicating that the mode of action of NAP1 is functionally conserved across species and that legumes have not evolved a unique functionality for NAP1 during rhizobial colonization. This work highlights the surprising commonality between polar-growing cells and a polar-growing cellular intrusion and reveals important insights into the formation and maintenance of infection-thread development.
Characterization of a Peanut Leaf Spot of Unknown Etiology
Authors: Cantonwine Emily G. , Culbreath Albert K. , Kemerait Robert C. , Gitaitis Ronald D.
Published: August 2010

Irregular leaf spot (ILS) of peanut was first noticed in Florida during the late 1990s. By 2000, ILS was apparent throughout much of the southeastern peanut growing region of the United States. Experiments were conducted to identify the cause of ILS, characterize ILS development over time, and evaluate the effect of genotype, tillage, and applications of fungicides and bactericides on ILS. Severities of ILS were near maximum levels at 33 to 42 days after planting (DAP) and in decline by 56 DAP. Incidence of ILS was greater in the lower canopy than the upper canopy. In most cases, ILS intensities were greater in strip-tilled plantings than conventional-tilled plantings and in the peanut breeding line UF-99325 than the cultivar Georgia Green. No fungicide or bactericide treatment suppressed ILS intensity. Attempts to isolate pathogenic fungi or bacteria from ILS lesions were unsuccessful. Although a pathogen cannot be totally dismissed as the cause of ILS, it is likely that ILS is caused by an abiotic factor.

Accepted for publication 17 May 2010. Published 27 July 2010.
Characterization and Pathogenicity ofBotryosphaeriaceaeSpecies Collected from Olive and Other Hosts in Spain and California
Authors: Moral Juan , Muñoz-Díez Concepción , González Nazaret , Trapero Antonio , Michailides Themis J.
Published: August 2010

Species in the family Botryosphaeriaceae are common pathogens causing fruit rot and dieback of many woody plants. In this study, 150 Botryosphaeriaceae isolates were collected from olive and other hosts in Spain and California. Representative isolates of each type were characterized based on morphological features and comparisons of DNA sequence data of three regions: internal transcribed spacer 5.8S, β-tubulin, and elongation factor. Three main species were identified as Neofusicoccum mediterraneum, causing dieback of branches of olive and pistachio; Diplodia seriata, causing decay of ripe fruit and dieback of olive branches; and Botryosphaeria dothidea, causing dalmatian disease on unripe olive fruit in Spain. Moreover, the sexual stage of this last species was also found attacking olive branches in California. In pathogenicity tests using unripe fruit and branches of olive, D. seriata isolates were the least aggressive on the fruit and branches while N. mediterraneum isolates were the most aggressive on both tissues. Isolates of B. dothidea which cause dalmatian disease on fruit were not pathogenic on branches and only weakly aggressive on fruit. These results, together with the close association between the presence of dalmatian disease symptoms and the wound created by the olive fly (Bactrocera oleae), suggest that the fly is essential for the initiation of the disease on fruit. Isolates recovered from dalmatian disease symptoms had an optimum of 26°C for mycelial growth and 30°C for conidial germination, suggesting that the pathogen is well adapted to high summer temperatures. In contrast, the range of water activity in the medium for growth of dalmatian isolates was 0.93 to 1 MPa, which was similar to that for the majority of fungi. This study resolved long-standing questions of identity and pathogenicity of species within the family Botryosphaeriaceae attacking olive trees in Spain and California.
Aqueous synthesis and characterization of Ag and Ag–Au nanoparticles: addressing challenges in size, monodispersity and structure
Authors: Mott Derrick , Thuy Nguyen T. B. , Aoki Yoshiya , Maenosono Shinya
Published: August 2010

In this paper, we demonstrate the synthesis of monodispersed silver nanoparticles (NPs) of controlled size (20.5 ± 3.3 nm) in aqueous phase from a silver hydroxide precursor with sodium acrylate as dual reducing–capping agent. We then coat these NPs in a layer of gold with controllable thickness through a reduction–deposition process. The materials are characterized using several techniques including high-resolution transmission electron microscopy, ultraviolet–visible spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The results show that we were able to synthesize not only monodispersed Ag NPs but also core–shell Ag–Au NPs with a discrete structure, which is significant because of the challenges associated with the creation of such materials, namely the propensity of metallic Ag to be oxidized by the presence of ionic Au. The NPs are of interest for use in a wide range of potential applications, including biomedical diagnostics and biomolecular detection as well as many others.
Single-molecule precursor-based approaches to cobalt sulphide nanostructures
Authors: Ramasamy Karthik , Maneerprakorn Weerakanya , Malik Mohammad A. , O'Brien Paul
Published: August 2010

Cobalt complexes of 1,1,5,5-tetramethyl-2,4-dithiobiuret, [Co{N(SCNMe
2
)
2
}
3
] (
1
), and 1,1,5,5-tetraisopropyl-2-thiobiuret, [Co{N(SOCN
i
Pr
2
)
2
}
2
] (
2
), have been synthesized and characterized. Both complexes were used as single-molecule precursors for the preparation of cobalt sulphide nanoparticles by thermolysis in hexadecylamine, octadecylamine or oleylamine. The powder X-ray diffraction pattern of as-prepared nanoparticles showed the hexagonal phase of Co

1−
x

S from complex
1
and mixtures of cubic and hexagonal Co
4
S
3
from complex
2
. Transmission electron microscopy images of material prepared from complex
1
showed spherical and trigonally shaped particles in the size range of 10–15 nm; whereas spheres, rods, trigonal prisms and pentagonally and hexagonally faceted crystallites were observed from complex
2
. This observation is the first of the Co
4
S
3
phase in a nanodispersed form.
Multilocus microsatellite typing for Rhizopus oryzae
Authors: Baghela Abhishek , Thungapathra M. , Shivaprakash M. R. , Chakrabarti Arunaloke
Published: August 2010

Rhizopus oryzae is the most frequent causative agent of zygomycosis. Although zygomycosis causes considerable morbidity and mortality in immunocompromised patients, the epidemiology of the disease is not well studied and no standard molecular typing method has been described for any of the causative agents. Here we describe a multilocus microsatellite typing (MLMT) method for R. oryzae. R. oryzae genome sequences were downloaded from the Fungal Genome Initiative database (Broad Institute). The intergenic regions and ORFs of approximately 5.7 Mb were screened for repeat regions with the help of the online repeat search tool Repeat Masker. Of the 30 microsatellite loci identified, 3 microsatellites [RO3, (CCT)
n
; RO4, (TA)
n
; and RO8, (GAA)(GGA)
n
] were selected after validation of the ability to amplify them and their size variation in 8 randomly selected clinical isolates of R. oryzae. Nucleotide sequence analysis of these loci demonstrated polymorphism in the microsatellite repeat number. The capabilities of these microsatellite loci were assessed for strain differentiation on 30 clinical isolates, based on fragment size determination in an automated capillary electrophoresis using fluorescent labelled primers. These three polymorphic microsatellite loci were found to have good discriminatory power (D) (RO3, D=0.846; RO4, D=0.747; RO8, D=0.742; with a combined D=0.986) and stability for seven subcultures. It was also confirmed that the MLMT method may be applied to both R. oryzae and Rhizopus delemar (a proposed new species), although MLMT analysis could not differentiate them into two clusters. The MLMT system, described here for what is believed to be the first time for a zygomycotic fungus, holds promise as a powerful tool for the strain typing of R. oryzae.
On English Domestic Cats
Authors: Pocock R. I.
Published: August 2010

The substance of the foregoing remarks may be epitomised as follows:–

The characters used by breeders and fanciers as a basis for their so‐called breeds of English Domestic Cats have no scientific value, in the sense of affording a clue to affinity and descent.

The pattern–or, in other words, the arrangement of the stripes–shows that English Domestic Oats are referable to two distinct types, whether they belong to the “Manx,”“Persian,” or “Short‐haired” breeds.

These two types of pattern are different in kind and do not intergrade. They are so distinct from each other that no one would hesitate to regard them as characterising two well‐marked species if the animals presenting them existed in a wild as opposed to a domesticated state.

In one type of pattern the stripes take the form of narrow transverse or vertical bands which sometimes break up into spots. To feral or domesticated examples of this Cat have been given many names, of which torquata is the best known and angorensis or striata possibly the oldest.

This Cat (torquata) was apparently domesticated in Europe at least as early as the 16 th century. There seems to be no reason therefore for regarding it as of Indian origin.

It closely resembles in pattern two existing species, namely, the so‐called Egyptian Cat (F. ocreata) and the European Wild Cat (F. sylvestris), both of which occur at the present day in the Mediterranean Region, and are very nearly related to each other. There is no difficulty in the way of believing that they are the ancestral forms or “agriotypes” of this domesticated race (torquata).

In the other type of pattern the stripes take the form of broad longitudinal or obliquely longitudinal bands forming a ring‐like or spiral arrangement on the sides of the abdomen. To domesticated examples of this Cat, Linnseus gave the name catus, which cannot be applied to any other form of the genus Felis. Domestica is its best‐known synonym.

This Cat (catus) is certainly known to have been domesticated in Europe in the middle of the 18th century. It was not, however, apparently known in India in the middle of the 19th century. Probably, therefore, it is of European descent.

Its origin is unknown. Of the several hypotheses that may be held on this subject perhaps the following two are the most to be commended:–that it arose as a sudden variation or sport from the torquata‐breed, in which case European Domestic Cats are dimorphic in pattern; that it is the direct descendant of some extinct Pleistocene Cat, in which case there are two distinct species of Domestic Cat in Europe.
A Contribution to the Skeletal Anatomy of the Frilled Shark, Chlamgdoselachus anguineus Gar
Authors: Goodey T.
Published: August 2010

Summary.

The following are a few of the most important points dealt with in the paper:—

The Membranous Labyrinth is described and figured for the first time, and it has been found to be of the usual selachian type, resembling rather closel that of Hexanchus griseus.

In the formation of the centra the following points are especially worthy of note:—

The preaence, at the anterior end of the vertebral column, of well‐developed, calcified cyclospondylic centra.

Slight constrictions of the notochord in the trunk region, best, seen in horiqontal longitudinal section, not calcified. The lowest stage in the development of centra.

In the main caudal region, calcified cyclospondylic centra of two sizes are present, corresponding with the doubling in the number of arcualia, which here, more than elsewhere in the vertebral column, grow round the notochord and greatly strengthen the centra.

The terminal caudal region is heterospondylic, and not monospondylic as in many other Selachians.

The musculature and skeleton of the mixipterygia are dealt with fully for the first time. In regard to the musculature I have to record the presence of both musc. fleœor internus and musc. flexor externus of Huber. In the skeleton I have found the modified radial β, and only one small intercalary cartilage b.1, not three as recorded by Günther.
The Fossil Crinoids referred to Hypocrinus Beyrich.
Authors: Bather F. A.
Published: August 2010

Summary.

The two specimens of Hypocrinus schueideri Beyr., described by Beyrich and Rothpletz respectively, are redescribed and refigured. The structure of the genus is shown to agree with that of the Devonian family Gasterocomidæ, but it is suggested that in this case and in that of “Lecythiocrinus” adamsi the distinctive features may have been independently acquired.

The holotype of “Hypocrinus” piriformis Rothpletz is redescribed and refigured, and proved to be no Hypocrinus. It is thought to be a highly modified descendant of the Taxocrinidæ, by way of such a genus as Cydonocrinus. The left posterior radial appears to have borne a large arm, but the other arms were more or less atrophied, and the right posterior radial has almost disappeared.
A Contribution to the Anatomy of the Three‐toed Sloth (Bradypus tridactylus)
Authors: Sonntag Chas. F.
Published: August 2010

The new facts recorded in this communication are:–

The full description of the mouth and tongue

The comparison between the palates of Bradypus and CholoEpus

The external relations of the compartments of the stomach, and the distribution of lymphatic glands in the Stomach‐wall.

Details of the internal structure of the stomach, and a complete account of the interior of the cæcal appendage.

The unusual and reptilian‐like situation of the pancreas, which results in complications in the peritoneum. The latter is fully described for the first, time in Bradypus tridactylus

The vessels arising from the aortic arch are different to previous accounts

The ligamentum arteriosuin of Bradypus is described for the first time.

The duct papillæ in the duodenum are different from the form which has already been described.

The comparison between the male and female pelves.
A Study of the Remarkable Tortoise, Testudo loveridgii Blgr., and the Morphogeny of the Chelonian Carapace.
Authors: Procter Joan B.
Published: August 2010

Summary.

Testudo loveridgii has an excessively depressed soft‐shelled carapace, and is able to inflate itself to a certain degree. It possesses a bony carapace and plastron, but they are extensively fenestrated, incomplete, and similar in essentials to the juvenile stages of other species.

Marginal plates five, six, and seven spread inwards in a unique manner, entering into the composition of the plastron and separating the hyo‐and hypoplastrons from each other. Their upper portions are extraordinarily shallow.

The ribs in T. loveridgii become (usually) entirely absorbed, apparently by the osteoclasts which are present beneath the periosteum. A simulacrum of the capitular portion, soft like ligament, and formed chiefly of periosteum, persists for some while.

The neural arch is vestigial and sometimes completely wanting, the neural plates being applied to the depressed centra to form the roof of the neural canal. Absorption probably takes place to some extent as in the ribs, but the arch is never more than a simple extent as in the ribs, but the arch is never more than a simple layer of bone, without spinous processes.

The jaws, together with their investing horny sheaths, are denticulated with remarkable regularity.
On the Structure of the Enamel in the Primates and some other Mammals.
Authors: Carter J. Thornton
Published: August 2010

Summary.

A microscopical examination of the teeth of Primates discloses the fact that all members of the suborder Lemuroidea possess, in a varying extent, the character of a penetration of tubes into the enamel.

In the Lemurinæ this penetration is slight, but in the Indrisinæ it is very rich.

The Galagos and Pottos also have a rich penetration, but in Nycticebus it is but feeble.

Tarsius has an enamel richly tubular, and in its structure essentially Lemurine.

A further interesting feature is that the pattern of the enamel in the Mascarene Lemurs differs from that of the Asian and African forms, and that the former has a structure identical with that found in the enamel of all Catarrhines, whilst the structure of the enamel in the Platyrrhines is identical with that found in the Asian and African Lemurs.

Two primitive Lemuroid Primates, Pelycodus and Notharctus, from the Eocene show no penetration, but in the structure of their enamel resemble the Mascarene Lemurs.

Hemiacodon, a Tarsioid Primate, also from the Eocene, has an enamel which is tubular, and in structure appears identical with the enamel of the recent Tarsius.

The enamel pattern affords a useful test of affinity if taken in conjunction with the character of a tube‐penetration, and enables one to discriminate between Multituberculates, Marsupials, and Placentals.
Miocene Proboscidia from Baluchistan.
Authors: Cooper C. Forster
Published: August 2010

Summary.

The Proboscidia of the Bugti beds of Baluchistan consist of form of Bunolophodon angustidens and a small Dinotherium.

The Indian B. angustidens is of a small type more primitive than the French forms from Sansan, nearer to Schlesinger's form subtapiroidea than his form typica, but not identical with it. Lydekker's subspecific name var. palceindica may be retained for the present until intermediate forms are found to occur. The genus Hemimastodon is not supported by material in the collection.

The Dinotherium is not found to differ from the smaller European forms nor from D. hobleyi of Africa, and it is doubtful in the present state of knowledge whether the Indian Dinotheres are separable from the European.
The Annual Increment of the Antlers of: the Red Deer (Cervus elaphus)
Authors: Huxley Julian S.
Published: August 2010

Summary.

The weights of the successive pairs of antlers of 37 Red Deer, 34 from the Warnham Court herd, are recorded. 33 series are recorded for the first time.

The mean annual increments in antler‐weight for the Warnham Court herd are as follows: (a) for all specimens for which data exist for 2 successive years; (b) for specimens for which data exist for 10 or more successive years:—

The season has a great influence on antler‐weight. In some seasons (e.g. 1924) practically all specimens produced very poor antlers, the percentage deviation from the mean of all antler‐weight increments for that year being ‐200 per cent.; while other seasons are very favourable, e. g. 1923, in which the corresponding deviation of weight‐increments was +143 per cent.

The unfavourable conditions of 1924 caused a marked absolute decrease in antler‐weight in 7th‐year stags, a less marked decrease in 6th‐year stags, and a slight absolute decrease in 5th‐year stags. In 4th‐year stags, however, though the growth was very much reduced, there was an absolute increase of antler‐weight.

Since 1900, when the treatment of the park at Warnham with lime was discontinued, the rapidity of antler‐growth has not been so great.

The conditions affecting antler‐growth are discussed.

A method is given for estimating quantitatively the average performance of individual stags with regard to antler‐production.

The number of points in 1st growth antlers at Warnham is frequently 4 instead of 2, and 9‐ and 12‐pointers have been seen. Correspondingly high numbers for 2nd and 3rd year heads are recorded.