bluuebunny/crossref_metadata_2025 huggingface dataset:
Focusing of electromagnetic beams in collisional plasmas, with finite thermal conduction
Authors: Sodha Mahendra Singh , Sharma Ashutosh , Agarwal Sujeet Kumar
Published: August 2006

In this paper we present a theoretical investigation of the focusing of coaxial Gaussian electromagnetic beams and of a Gaussian ripple on an electromagnetic beam of uniform irradiance in a collisional plasma (in thermal equilibrium in the absence of the beams). A self consistent solution of the electromagnetic wave equation, the energy balance equation, and Fourier’s equation of heat conduction has been obtained in the paraxial approximation. The nonuniform distribution of the electron density and thereby the dielectric function on account of the nonuniform electron temperature/density distribution causes the focusing/defocusing of the beams. The effect of thermal conduction on the temperature distribution of the electrons, on the critical curves, and the nature of focusing has been specifically studied. In common with earlier studies, three regions in the initial beam width—initial axial irradiance plane, corresponding to steady divergence, self focusing and oscillatory divergence have been characterized. Numerical computations have been made for an ionic collisions dominated plasma.
ZnO tetrapod Schottky photodiodes
Authors: Newton Marcus C. , Firth Steven , Warburton Paul A.
Published: August 2006

The fabrication of an ultraviolet photodiode employing a single ZnO tetrapod nanocrystal is reported. This diode structure is prepared by depositing W and Pt electrodes to form Ohmic and Schottky contacts, respectively. Dark current-voltage measurements show rectifying behavior. The properties of the metal-semiconductor interface are studied with above and below band gap illumination. It is found that with increasing UV excitation the device converts from a rectifying to an Ohmic behavior. This effect is attributed to a flattening of the energy bands due to the migration of photogenerated carriers within the space charge region at the metal-semiconductor interface.
Actuation of cantilevers by optical trapping
Authors: Domachuk Peter , Mägi Eric , Eggleton Benjamin J. , Cronin-Golomb Mark
Published: August 2006

Cantilevers are commonly used in microelectromechanical systems for sensing and optical switching applications. The authors demonstrate the use of optical tweezers for all optical actuation of a tapered optical fiber used as a cantilever and to drive it as a micromechanical oscillator. A fiber optic confocal detection system is used to monitor backscattered trapping light to sense the position and oscillation characteristics of the cantilever. Potential applications include optical switching and dynamic reconfigurability of photonic circuits.
High-resolution dynamic light scattering using a software correlator with analog detection
Authors: Wang Gang , Xue Yan , Kang Zhi-Hui , Jiang Yun , Zhao Zhi-Sheng , Gao Jin-Yue
Published: August 2006

In this article, a dynamic light scattering (DLS) experimental system with 12.5ns time resolution has been realized based on the use of a photomultiplier tube, a virtual digital storage oscilloscope module, and a personal computer. This experimental system is designed to work on analog detection, in which the photomultiplier output is used directly as an analog signal. Several tests about this system are carried out and the time resolution of this system is demonstrated theoretically and experimentally. From the data and the result, this system is feasible to execute the DLS experiment.
Magnetically driven cold valve for He4
Authors: Bueno J. , Blaauwgeers R. , Partapsing R. , Taminiau I. , Jochemsen R.
Published: August 2006

We have designed a low temperature valve for liquid helium, which uses a magnetic field gradient and a permanent magnet to close. For closing, it presses a small ruby ball onto a Torlon seat. We present a small valve that is easy to build and easily controlled via two wires. It has a fast response, reliable, and has the advantage that there is no dead volume change on closing and no additional helium line is required to operate.
Construction and applications of an atomic magnetic gradiometer based on nonlinear magneto-optical rotation
Authors: Xu Shoujun , Rochester Simon M. , Yashchuk Valeriy V. , Donaldson Marcus H. , Budker Dmitry
Published: August 2006

We report on the design, characterization, and applications of a sensitive atomic magnetic gradiometer. The device is based on nonlinear magneto-optical rotation in alkali-metal (Rb87) vapor and uses frequency-modulated laser light. The magnetic field produced by a sample is detected by measuring the frequency of a resonance in optical rotation that arises when the modulation frequency equals twice the Larmor precession frequency of the Rb atoms. The gradiometer consists of two atomic magnetometers. The rotation of light polarization in each magnetometer is detected with a balanced polarimeter. The sensitivity of the gradiometer is 0.8nG∕Hz1∕2 for near-dc (0.1Hz) magnetic fields, with a base line of 2.5cm. For applications in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI), a long solenoid that pierces the magnetic shields provides an ∼0.5G leading field for the nuclear spins in the sample. Our apparatus is particularly suited for remote detection of NMR and MRI. We demonstrate a point-by-point free induction decay measurement and a spin echo reconstructed with a pulse sequence similar to the Carr-Purcell-Meiboom-Gill pulse. Additional applications and future improvements are also discussed.
Scanning mass spectrometry with integrated constant distance positioning
Authors: Li Nan , Eckhard Kathrin , Aßmann Jens , Hagen Volker , Otto Horst , Chen Xingxing , Schuhmann Wolfgang , Muhler Martin
Published: August 2006

Scanning mass spectrometry is of growing importance for the characterization of catalytically active surfaces. The instrument presented here is capable of measuring catalytic activity spatially resolved by means of two concentric capillaries. The outer one is used for cofeeding reactants such as ethene and hydrogen to the sample surface, whereas the inner one is pumping off the product mixture as inlet to a quadrupole mass spectrometer. Three-dimensional measurements under stagnant-point flow conditions become possible based on a home-built capillary positioning unit. Step-motor driven positioning stages exhibiting a minimum step width of 2.5μm̸half step are used for the x, y positioning, and the step motor in z direction has a resolution of 1μm̸half step. The system is additionally equipped with a feedback loop for following the topography of the sample throughout scanning. Hence, the obtained catalytic data are unimpaired by signal changes caused by the morphology of the investigated structure. For distance control the argon ion current is used originating from externally fed argon diffusing into the confined space between the accurately positioned capillaries and the sample surface. A well-defined microchannel flow field with 400μm wide channels and 200μm wide mounds was chosen to evaluate the developed method. The catalytic activity of a Pt catalyst deposited on glassy carbon was successfully visualized in constant probe to sample distance. Simultaneously, the topography of the sample was recorded derived from the z positioning of the capillaries.
Solute-solvent contact by intermolecular cross relaxation. I. The nature of the water-hydrophobic interface
Authors: Nordstierna Lars , Yushmanov Pavel V. , Furó István
Published: August 2006

Intermolecular cross-relaxation rates between solute and solvent were measured by {H1} F19 nuclear magnetic resonance experiments in aqueous molecular solutions of ammonium perfluoro-octanoate and sodium trifluoroacetate. The experiments performed at three different magnetic fields provide frequency-dependent cross-relaxation rates which demonstrate clearly the lack of extreme narrowing for nuclear spin relaxation by diffusionally modulated intermolecular interactions. Supplemented by suitable intramolecular cross-relaxation, longitudinal relaxation, and self-diffusion data, the obtained cross-relaxation rates are evaluated within the framework of recent relaxation models and provide information about the hydrophobic hydration. In particular, water dynamics around the trifluoromethyl group in ammonium perfluoro-octanoate are more retarded than that in the smaller trifluoroacetate.
Cooperative effects, strengths of hydrogen bonds, and intermolecular interactions in circular cis, trans-cyclotriazane clusters (n=3–8)
Authors: Song Hua-Jie , Xiao He-Ming , Dong Hai-Shan
Published: August 2006

Based on Becke’s three parameter functional [J. Chem. Phys. 98, 5648 (1993)] of density functional theory (DFT) with the correlation of Lee-Yang-Parr [Phys. Rev. B 37, 785 (1988)] (DFT/B3LYP), the natural bond orbital (NBO) analysis, the Bader’s theory of atoms in molecule (AIM), our calculations indicate that as cluster size (n) increases, the n-dependent cooperative changes in the lengths of the N⋯H H bonds (HBs) and N–H bonds, the N–H stretching frequencies and intensities, and the n(N)→σ*(N–H) charge transfers are observed to be pervasive in the circular cis, trans-cyclotriazane clusters (n=3–8), which is very different from the linear cis, trans-cyclotriazane clusters reported in previous work. According to the NBO and AIM theories, the cooperativity of the intermolecular n(N)→σ*(N–H) interaction leads to the n-dependent N⋯H contractions. In this way, the stronger N⋯H bond is formed, as reflected in the increase in their ρ(rcp) values. This increased electron density is translated into the improved capacity to concentrate electrons at the HB bond critical point (BCP), i.e., a higher potential energy V(rcp). On the other hand, stronger repulsion is also activated to counteract the contraction, which is reflected in the increased G(rcp) value that gives the tendency of the system to dilute electrons at the HB BCP. In terms of the three-body symmetry-adapted perturbation theory (three-body SAPT), the induction nonadditivity accounts for up to 97% of the nonadditive energy in the circular trimer. It can believed that the marked cooperativity of the n(N)→σ*(N–H) interactions is of nonadditive induction in nature. The N⋯H formation and nature of cooperativity in the circular clusters differ from those in the linear clusters that have been reported previously. According to the SAPT(DFT) method which is a combination of SAPT with the asymptotically corrected DFT, the cis, trans-cyclotriazane systems should contain remarkable dispersion interactions. However, the short-range dispersion cannot be reproduced thoroughly by DFT/B3LYP. A quantum cluster equilibrium model illustrates the neglected dispersion energies and the nonadditive energies can affect markedly the properties of the liquid consisting of the circular clusters.
Fluid-crystal coexistence for proteins and inorganic nanocolloids: Dependence on ionic strength
Authors: Prinsen Peter , Odijk Theo
Published: August 2006

We investigate theoretically the fluid-crystal coexistence of solutions of globular charged nanoparticles such as proteins and inorganic colloids. The thermodynamic properties of the fluid phase are computed via the optimized Baxter model P. Prinsen and T. Odijk [J. Chem. Phys. 121, 6525 (2004)]. This is done specifically for lysozyme and silicotungstates for which the bare adhesion parameters are evaluated via the experimental second virial coefficients. The electrostatic free energy of the crystal is approximated by supposing the cavities in the interstitial phase between the particles are spherical in form. In the salt-free case a Poisson-Boltzmann equation is solved to calculate the effective charge on a particle and a Donnan approximation is used to derive the chemical potential and osmotic pressure in the presence of salt. The coexistence data of lysozyme and silicotungstates are analyzed within this scheme, especially with regard to the ionic-strength dependence of the chemical potentials. The latter agree within the two phases provided some upward adjustment of the effective charge is allowed for.
Microhydration shell structure in Cl2∙−∙nH2O clusters: A theoretical study
Authors: Pathak A. K. , Mukherjee T. , Maity D. K.
Published: August 2006

We present the results of a detailed study on structure and electronic properties of hydrated cluster Cl2∙−∙nH2O (n=1–7) based on a nonlocal density functional, namely, Becke’s [J. Chem. Phys. 98, 1372 (1993)] half and half hybrid exchange-correlation functional with a split valence 6-311++G(d,p) basis function. Geometry optimizations for all the clusters are carried out with various possible initial guess structures without any symmetry restriction. Several minimum energy structures (conformers) are predicted with a small difference in total energy. There is a competition between the binding of solvent H2O units with Cl2∙− dimer radical anion directly through ion-molecule interaction and forming interwater hydrogen-bonding network in Cl2∙−∙nH2O (n⩾2) hydrated cluster. Structure having interwater H-bonded network is more stable over the structure where H2O units are connected to the solute dimer radical anion Cl2∙− rather independently either by single or double H bonding in a particular size (n) of hydrated cluster Cl2∙−∙nH2O. At the maximum four solvent H2O units reside in interwater H-bonding network present in these hydrated clusters. It is observed that up to six H2O units are independently linked to the anion having four double H bondings and two single H bondings suggesting the primary hydration number of Cl2∙− to be 6. In all these clusters, the odd electron is found to be mostly localized over the two Cl atoms and these two atoms are bound by a three-electron hemibond. Calculated interaction (between solute and different water clusters) and vertical detachment energy profiles show saturation at n=6 in the hydrated cluster Cl2∙−∙nH2O (n=1–7). However, calculated solvation energy increases with the increase in number of solvent H2O molecules in the cluster. Interaction energy varies linearly with vertical detachment energy for the hydrated clusters Cl2∙−∙nH2O (n⩽6). Calculation of the vibration frequencies show that the formation of Cl2∙−-water clusters induces significant shifts from the normal stretching modes of isolated water. A clear difference in the pattern of IR spectra is observed in the O–H stretching region of water from hexa- to heptahydrated cluster.
Electrical and structural investigations of Ag-based Ohmic contacts for InAlAs∕InGaAs∕InP high electron mobility transistors
Authors: Zhao Weifeng , Wang Liang , Adesida Ilesanmi
Published: August 2006

Ge ∕ Ag ∕ Ni and AuGe∕Ni∕Au Ohmic contacts on InAlAs∕InGaAs∕InP high electron mobility transistors with excellent contact resistance of 0.07Ωmm were obtained after annealing at 425 and 265°C, respectively. The Ag-based contacts have a large processing window of >130°C. Structural analyses confirm that Ag and Au protrusions created during annealing effectively linked the two-dimensional electron gas layer with the metal contacts to produce excellent Ohmic characteristics. The formation of liquid AuGe eutectic phase in AuGe∕Ni∕Au at 300°C is believed to cause overannealing. The eutectic temperature of Ag–Ge is ∼300°C higher leading to a higher optimum annealing temperature and a wider processing window for the Ge∕Ag∕Ni contacts.
Enhancement-mode metal-oxide-semiconductor single-electron transistor on pure silicon
Authors: Jones G. M. , Hu B. H. , Yang C. H. , Yang M. J. , Hajdaj Russell , Hehein Gerard
Published: August 2006

The authors demonstrate a silicon-based single-electron transistor (SET) in the few-electron regime. Our structure is similar to a metal-oxide-semiconductor field-effect transistor. The substrate, however, is undoped and could be isotope enriched so that any nonuniformity and spin decoherence due to impurity and nuclear spins can be minimized. A bilayer-gated configuration provides flexibility in manipulating single electrons. The stability chart measured at 4.2K shows diamondlike domains with a charging energy of 18meV, indicating a quantum dot of 20nm in diameter. The benefits of using this enhancement-mode SET in silicon and its potential application for scalable quantum computing are discussed.
Optical absorption and luminescence energies of F centers in CaO from ab initio embedded cluster calculations
Authors: Carrasco Javier , Sousa Carmen , Illas Francesc , Sushko Peter V. , Shluger Alexander L.
Published: August 2006

We calculated the optical absorption and luminescence energies of electrons trapped at oxygen vacancies in CaO using a consistent embedded cluster method which accounts for the long-range polarization effects and partial covalence of CaO. Optical absorption and luminescence energies of neutral (F center) and positively charged (F+ center) vacancies are calculated by means of time dependent density functional theory using the B3LYP exchange-correlation density functional. Our results demonstrate that using large basis sets to describe a diffuse nature of excited states, and properly accounting for long-range polarization induced by charged and excited defect states, is crucial for accurate predictions of optical excitation and luminescence energies of these defects.
Work hardening ability of ductile Ti45Cu40Ni7.5Zr5Sn2.5 and Cu47.5Zr47.5Al5 bulk metallic glasses
Authors: Kim K. B. , Das J. , Venkataraman S. , Yi S. , Eckert J.
Published: August 2006

Ductile Ti45Cu40Ni7.5Zr5Sn2.5 and Cu47.5Zr47.5Al5 bulk metallic glasses (BMGs) present different work hardening abilities under compression. Microstructural investigations reveal that nanoscale chemical heterogeneities occur throughout the samples. The morphology of the chemically heterogeneous domains in the as-cast Ti45Cu40Ni7.5Zr5Sn2.5 BMG is irregular and significantly interconnected. In contrast, the as-cast Cu47.5Zr47.5Al5 BMG exhibits a spherical morphology of the chemically heterogeneous regions. Furthermore, the distribution of the nanoscale chemical heterogeneity is macroscopically inhomogeneous throughout the material. These findings suggest that the different work hardening abilities of the Ti45Cu40Ni7.5Zr5Sn2.5 and Cu47.5Zr47.5Al5 BMGs possibly originate from the different morphologies and distributions of the chemically heterogeneous regions.
The Cycle of Fragmentation and Sprawl: A Conceptual Framework and Empirical Model
Authors: Ulfarsson Gudmundur F , Carruthers John I
Published: August 2006

The political and spatial dimensions of US metropolitan areas are eminently interconnected through a recurring cycle of fragmentation and sprawl. In this paper we demonstrate the cycle at work by refining a land-use model developed in a previous paper and applying it to a national dataset of metropolitan counties. The recursive simultaneous-equations model is structured around five-year intervals, and enables us to observe how the political landscape (urban development patterns) at time t − 5 affects spatial outcomes (municipal fragmentation) at time t. The results suggest that regulatory failure may bear as much fault for urban sprawl as the more commonly cited market failures, and that it may therefore be worthwhile to shift the focus of the sprawl/antisprawl debate from its physical to its political dimensions. Future research should focus on identifying the systematic nature of sprawl and, as an extension, the various policy levers that may be used to mitigate its negative consequences. The paper improves on previous research in four key ways: by describing the underlying theory in greater detail; by rounding out the recursive relationship; by enriching the set of interdependent variables; and by expanding the geographic scope of the model. Its primary contribution is to deepen the pool of empirical evidence linking political structure to patterns of growth and change in US metropolitan regions.
New species and records of Rhodocybe (Entolomataceae, Agaricales) from Tasmania
Authors: Baroni Timothy J. , Gates Genevieve M.
Published: August 2006

Five new and two previously unrecorded species of Rhodocybe (Agaricales, fungi) are described from the Australian state of Tasmania with a key provided to species known from Australia and New Zealand. This is the first report of Rhodocybe taxa for Tasmania, and increases the known number of species of this genus for the Australia / New Zealand region from 13 to 18. The newly described species of Rhodocybe are R. pseudopiperita, R. lateritia, R. pallidogrisea, R. tasmanica and R. amara.
Swimming
Paramecium
in magnetically simulated enhanced, reduced, and inverted gravity environments
Authors: Guevorkian Karine , Valles James M.
Published: August 2006

Earth's gravity exerts relatively weak forces in the range of 10–100 pN directly on cells in biological systems. Nevertheless, it biases the orientation of swimming unicellular organisms, alters bone cell differentiation, and modifies gene expression in renal cells. A number of methods of simulating different strength gravity environments, such as centrifugation, have been applied for researching the underlying mechanisms. Here, we demonstrate a magnetic force-based technique that is unique in its capability to enhance, reduce, and even invert the effective buoyancy of cells and thus simulate hypergravity, hypogravity, and inverted gravity environments. We apply it to
Paramecium caudatum
, a single-cell protozoan that varies its swimming propulsion depending on its orientation with respect to gravity,
g
. In these simulated gravities, denoted by

f
gm

,
Paramecium
exhibits a linear response up to

f
gm

= 5
g
, modifying its swimming as it would in the hypergravity of a centrifuge. Moreover, experiments from

f
gm

= 0 to −5
g
show that the response is symmetric, implying that the regulation of the swimming speed is primarily related to the buoyancy of the cell. The response becomes nonlinear for

f
gm

>5
g
. At

f
gm

= 10
g
, many paramecia “stall” (i.e., swim in place against the force), exerting a maximum propulsion force estimated to be 0.7 nN. These findings establish a general technique for applying continuously variable forces to cells or cell populations suitable for exploring their force transduction mechanisms.
A mitotically inheritable unit containing a MAP kinase module
Authors: Kicka Sébastien , Bonnet Crystel , Sobering Andrew K. , Ganesan Latha P. , Silar Philippe
Published: August 2006

Prions are novel kinds of hereditary units, relying solely on proteins, that are infectious and inherited in a non-Mendelian fashion. To date, they are either based on autocatalytic modification of a 3D conformation or on autocatalytic cleavage. Here, we provide further evidence that in the filamentous fungus
Podospora anserina
, a MAP kinase cascade is probably able to self-activate and generate
C
, a hereditary unit that bears many similarities to prions and triggers cell degeneration. We show that in addition to the MAPKKK gene, both the MAPKK and MAPK genes are necessary for the propagation of
C
, and that overexpression of MAPK as that of MAPKKK facilitates the appearance of
C
. We also show that a correlation exists between the presence of
C
and localization of the MAPK inside nuclei. These data emphasize the resemblance between prions and a self-positively regulated cascade in terms of their transmission. This thus further expands the concept of protein-base inheritance to regulatory networks that have the ability to self-activate.
Quantification of protein half-lives in the budding yeast proteome
Authors: Belle Archana , Tanay Amos , Bitincka Ledion , Shamir Ron , O’Shea Erin K.
Published: August 2006

A complete description of protein metabolism requires knowledge of the rates of protein production and destruction within cells. Using an epitope-tagged strain collection, we measured the half-life of >3,750 proteins in the yeast proteome after inhibition of translation. By integrating our data with previous measurements of protein and mRNA abundance and translation rate, we provide evidence that many proteins partition into one of two regimes for protein metabolism: one optimized for efficient production or a second optimized for regulatory efficiency. Incorporation of protein half-life information into a simple quantitative model for protein production improves our ability to predict steady-state protein abundance values. Analysis of a simple dynamic protein production model reveals a remarkable correlation between transcriptional regulation and protein half-life within some groups of coregulated genes, suggesting that cells coordinate these two processes to achieve uniform effects on protein abundances. Our experimental data and theoretical analysis underscore the importance of an integrative approach to the complex interplay between protein degradation, transcriptional regulation, and other determinants of protein metabolism.
First Year of Mandatory Reporting of Healthcare-Associated Infections, Pennsylvania An Infection Control—Chart Abstractor Collaboration
Authors: Julian Kathleen G. , Brumbach Arlene M. , Chicora Michelle K. , Houlihan Carol , Riddle Anna M. , Umberger Teanna , Whitener Cynthia J.
Published: August 2006

Background.

In 2004, the Commonwealth of Pennsylvania mandated hospitals to report healthcare-associated infections (HAIs). The increased workload led our Infection Control staff to collaborate with Atlas, a group of chart abstractors.

Objective.

The objective of this study was to assess our first year of experience with mandatory reporting of HAIs—specifically, to assess Atlas' contribution to surveillance.

Design.

Cases were selected if they had 1 or more of the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes designated by Pennsylvania as a possible HAI. After training by the Infection Control staff, Atlas applied National Nosocomial Infection Surveillance (NNIS) system case definitions for catheter-associated urinary tract infections (UTIs) and surgical site infections (SSIs), and they applied NNIS chest imaging criteria to eliminate cases that were not ventilator-associated pneumonia (VAP). To assess Atlas' performance, Infection Control staff conducted a parallel review.

Results.

For discharges from the hospital during the fourth quarter of 2004, a total of 410 UTIs, 59 SSIs, and 56 VAPs were identified on the basis of state-designated ICD-9-CM codes; review by Atlas/Infection Control determined that 15%, 15%, and 16% of cases met case definitions, respectively. Of cases reviewed by both Infection Control and Atlas, 87% of the assessments made by Atlas were correct for UTI, and 96% were correct for SSI. For VAP, Infection Control concluded that 39% of cases could be ruled out on the basis of chest imaging criteria; Atlas correctly dismissed these 12 cases but incorrectly dismissed an additional 6 (error, 19%). Surveillance was not timely: 1-2 months elapsed between the time of HAI onset and the earliest case review.

Conclusions.

With ongoing training by Infection Control, Atlas successfully demonstrated a role in retrospective HAI surveillance. However, despite a major effort to comply with mandates, time lags and other design limitations rendered the data of low utility for Infection Control. States that are planning HAI-reporting programs should standardize an efficient surveillance methodology that yields data capable of guiding interventions to prevent HAI.
Blood Pressure Cuff as a Potential Vector of Pathogenic Microorganisms A Prospective Study in a Teaching Hospital
Authors: Gialluly C. de , Morange V. , Gialluly E. de , Loulergue J. , van der Mee N. , Quentin R.
Published: August 2006

Objective.

To investigate the potential role of blood pressure (BP) cuffs in the spread of bacterial infections in hospitals.

Design.

A comprehensive, prospective study quantitatively and qualitatively evaluating the bacterial contamination on BP cuffs of 203 sphygmomanometers in use in 18 hospital units from January through March 2003.

Setting.

A university hospital with surgical, medical, and pediatric units.

Results.

A level of contamination reaching 100 or more colony-forming units per 25 cm2was observed on 92 (45%) of inner sides and 46 (23%) of outer sides of 203 cuffs. The highest rates of contamination occurred on the inner side of BP cuffs kept in intensive care units (ICUs) (20 [83%] of 24) or on nurses' trolleys (27 [77%] of 35). None of the 18 BP cuffs presumed to be clean (ie, those that had not been used since the last decontamination procedure) had a high level of contamination. Potentially pathogenic microorganisms were isolated from 27 (13%) of the 203 BP cuffs: 20 of these microorganisms wereStaphylococcus aureus, including 9 methicillin-resistant strains. The highest rates of contamination with potentially pathogenic microorganisms were observed on cuffs used in ICUs and those kept on nurses' trolleys. For 4 patients with a personal sphygmomanometer, a genetic link was found between the strains isolated from the BP cuffs and the strains isolated from the patients.

Conclusions.

The results of this survey highlight the importance of recognizing BP cuffs as potential vectors of pathogenic bacteria among patients and as a source of reinfection when dedicated to a single patient, emphasizing the urgent need for validated procedures for their use and maintenance.
Interinstitutional and Intrainstitutional Transmission of a Strain ofAcinetobacter baumanniiDetected by Molecular Analysis Comparison of Pulsed-Field Gel Electrophoresis and Repetitive Sequence–Based Polymerase Chain Reaction
Authors: Saeed S. , Fakih M. G. , Riederer K. , Shah A. R. , Khatib R.
Published: August 2006

Pulsed-field gel electrophoresis and repetitive sequence-based polymerase chain reaction provided comparable strain discrimination with minor discordance in typingAcinetobacter baumanniiclinical isolates from patients at our hospital and affiliated institutions. Typing revealed a cluster strain with intrainstitutional and interinstitutional spread during the study period. A long-term acute care facility may have been the reservoir.
On the distribution of the order over residue classes
Authors: Moree Pieter
Published: August 2006

For a fixed rational number

g
∉
{
−
1
,
0
,
1
}

g\not \in \{-1,0,1\}

and integers

a
a

and

d
d

we consider the set

N
g

(
a
,
d
)

N_g(a,d)

of primes

p
p

such that the order of

g
g

modulo

p
p

is congruent to

a

(

mod~

d
)

a\,(\textrm {mod~}d)

. Under the Generalized Riemann Hypothesis (GRH), it can be shown that the set

N
g

(
a
,
d
)

N_g(a,d)

has a natural density

δ
g

(
a
,
d
)

\delta _g(a,d)

. Arithmetical properties of

δ
g

(
a
,
d
)

\delta _g(a,d)

are described, and

δ
g

(
a
,
d
)

\delta _g(a,d)

is compared with

δ
(
a
,
d
)

\delta (a,d)

: the average density of elements in a field of prime characteristic having order congruent to

a

(

mod~

d
)

a\,(\textrm {mod~}d)

. It transpires that

δ
g

(
a
,
d
)

\delta _g(a,d)

has a strong tendency to be equal to

δ
(
a
,
d
)

\delta (a,d)

, or at least to be close to it.
Habitat suitability for tsessebe Damaliscus lunatus lunatus
Authors: Dörgeloh Werner G.
Published: August 2006

The distribution and numbers of tsessebe (Damaliscus lunatus lunatus) have declined considerably in South Africa, partly due to deteriorating habitat conditions. Identifying important habitat variables will assist in managing the species. The objective of this study was to identify habitat variables important for tsessebe and to develop a predictive model of habitat selection for this species in a savanna biome. The study was conducted in the Nylsvley Nature Reserve over a 2‐year period. A total of eighteen habitat variables were measured in ten plant communities at 200 sites. Logistic regression analyses were used to identify predictor variables and to construct a habitat model. Tsessebe were found <2 km from the nearest source of water, in flat areas with slopes of <3° and with <10% rockiness. Their distribution was not influenced by the woody component. Sites where tsessebe were present had significantly lower grass heights and tuft heights, with a higher grass density compared with areas not utilized by tsessebe. Nitrogen and sodium levels were also higher at present sites. Habitat type and grass height were the most significant predictors of tsessebe presence. The selected model had an overall percentage prediction of 85.0%. The model was subdivided into five vegetation‐specific models and each model was tested with independent data.
Correlation between chemical structure and biological activities of Porphyromonas gingivalis synthetic lipopeptide derivatives
Authors: Makimura Y , Asai Y , Taiji Y , Sugiyama A , Tamai R , Ogawa T
Published: August 2006

We recently separated a PG1828-encoded triacylated lipoprotein (Pg-LP), composed of two palmitoyl and one pentadecanoyl groups at the N-terminal of glycerocysteine from Porphyromonas gingivalis, a periodontopathic bacteria, and found that Pg-LP exhibited definite biological activities through Toll-like receptor (TLR) 2. In the present study, we synthesized 12 different Pg-LP N-terminal peptide moieties (PGTP) using four combinations of glyceryl (R and S) and cysteinyl (l and d) stereoisomers, and three different acyl group regioisomers, N-pentadecanoyl derivative (PGTP1), S-glycero 2-pentadecanoyl derivative (PGTP2) and S-glycero 3-pentadecanoyl derivative (PGTP3). All the PGTP compounds (RL, SL, SD, RD) tested showed TLR2-dependent cell activation. The activating capacities of the PGTP-R compounds were more potent than those of the PGTP-S compounds, whereas there were no differences between the PGTP-L and -D compounds. Furthermore, the production of interleukin (IL)-6 following stimulation with the PGTP1-RL, PGTP2-RL and PGTP3-RL compounds was impaired in peritoneal macrophages from TLR2 knock-out (KO), but not those from TLR1 KO or TLR6 KO mice. These results suggest that P. gingivalis triacylated lipopeptides are capable of activating host cells in a TLR2-dependent and TLR1-/TLR6-independent manner, and the fatty acid residue at the glycerol position in the PGTP molecule plays an important role in recognition by TLR2.
Cathepsins B, L and D in inflammatory bowel disease macrophages and potential therapeutic effects of cathepsin inhibition in vivo
Authors: Menzel K , Hausmann M , Obermeier F , Schreiter K , Dunger N , Bataille F , Falk W , Scholmerich J , Herfarth H , Rogler G
Published: August 2006

The cathepsins D (CTSD), B (CTSB) and L (CTSL) are important for the intracellular degradation of proteins. Increased cathepsin expression is associated with inflammatory diseases. We have shown previously an induction of CTSD expression in intestinal macrophages (IMAC) in inflamed mucosa of patients with inflammatory bowel disease (IBD). Here we investigated the regulation of CTSB and CTSL in IMAC during IBD and effects of CTSD and CTSB/CTSL inhibition in vivo. Human IMAC were isolated from normal and inflamed mucosa. Reverse transcription–polymerase chain reaction (RT–PCR) was performed for CTSB and CTSL mRNA. Immunostaining was used to confirm PCR results. Cathepsin inhibition was investigated in the dextran–sulphate–sodium (DSS) colitis model in mice with application of pepstatin A (CTSD inhibitor), CA-074 (CTSB inhibitor) and Z-Phe-Tyr-aldehyde (CTSL inhibitor). CTSL mRNA was significantly up-regulated in IMAC isolated from IBD mucosa. Up-regulated protein expression was found mainly in areas of mucosal damage by immunostaining. Inhibition of CTSD in mouse DSS colitis was followed by an amelioration of the disease. Inhibitor-treated mice showed a significant lower histological score (HS) and less colon reduction in comparison to controls. Similarly, simultaneous inhibition of CTSB/CTSL was followed by a significant amelioration of colitis. Expression of tissue-degrading cathepsins is increased in IMAC in IBD. Inhibition of CTSD as well as CTSB/CTSL is followed by an amelioration of experimental colitis. The prevention of mucosal damage by cathepsin inhibition could represent a new approach for the therapy of IBD.
Effects of the IGF‐I/IGFBP‐3 complex on GH and ghrelin nocturnal concentrations in low birth weight children
Authors: Iñiguez German , Salazar Teresa , Roman Rossana , Avila Alejandra , Gunn Ronald D. , Cassorla Fernando
Published: August 2006

Objective  There is limited information regarding the effects of IGF‐I and/or IGFBP‐3 on circulating ghrelin concentrations. To determine the effects of IGF‐I on GH and ghrelin concentrations, we examined the GH and ghrelin nocturnal profiles before and after the administration of the IGF‐I/–IGFBP‐3 complex (Iplex™) to low birth weight children.

Design  The children were studied on two separate occasions, the first under basal conditions, and the second time after the sc administration of 1 mg/kg of Iplex™ at 2100 h. Blood samples for determination of GH and ghrelin were obtained every 20 min between 2300 h and 0700 h, while the children were sleeping. In each patient, we calculated the mean GH and ghrelin area under the curve (GH AUC and GHR AUC), both under basal conditions and after the administration of the IGF‐I/IGFBP‐3 complex.

Setting  The study was performed at a University Research Centre located at a General Hospital in Santiago, Chile.

Patients  Twenty prepubertal children (11 boys and 9 girls), born after a full‐term pregnancy with a birth weight below 2·8 kg were studied at a mean ± SEM age of 7·3 ± 0·5 years (range 4–11 years). Their mean height was −1·8 ± 0·3 standard deviation score (SDS) and their mean BMI was 0·1 ± 0·2 SDS at the time of the study.

Main outcome and results  Mean nocturnal GH AUC exhibited a significant decrease (2903 ± 185 vs 1860 ± 122 ng/ml min, P < 0·01), whereas mean GHR AUC showed a significant increase after administration of the IGF‐I/IGFBP‐3 complex (68 ± 16 vs 288 ± 36 ng/ml min, P < 0·01).

Conclusions  These findings indicate that the IGF‐I/IGFBP‐3 complex appears to have opposite effects on circulating GH and ghrelin concentrations in low birth weight children, suggesting that, in addition to its known negative feed‐back effect on GH, IGF‐I and/or IGFBP‐3 may have a positive feed‐back effect on ghrelin.
BCL2 gene abnormalities define distinct clinical subsets of follicular lymphoma
Authors: Goodlad J R , Batstone P J , Hamilton D A , Kernohan N M , Levison D A , White J M
Published: August 2006

Aims:  Follicular lymphoma (FL) arising primarily in the skin has recently been proposed as a distinct entity on the basis of a low incidence of t(14;18)(q32;q21) and bcl‐2 expression, with a very high percentage of patients surviving more than 5 years. However, cases of t(14;18)(q32;q21)‐positive primary cutaneous FL (PCFL) and examples of t(14;18)(q32;q21)‐negative FL at nodal and other extranodal sites, are well documented. The aim of this study was to test the hypothesis that there is a subtype of FL lacking t(14;18)(q32;q21), which preferentially involves certain sites but is not restricted by anatomical location.

Methods and results:  A cohort of 47 stage 1 FL was stratified according to the presence or absence of t(14;18)(q32;q21) using conventional cytogenetics, polymerase chain reaction and interphase fluorescence in situ hybridization. Compared with t(14;18)(q32;q21)‐positive cases, FL lacking the translocation were less likely to express CD10 or bcl‐2 (P < 0.01), made up a significantly greater proportion of cases arising at extranodal sites (P < 0.001) and had a significantly better overall and disease‐specific 5‐year survival (P < 0.01).

Conclusions:  These results support the concept of a subtype of FL lacking t(14;18)(q32;q21), characterized by low‐intensity bcl‐2 expression, a predilection for extranodal sites, particularly the skin, and a more favourable outcome than t(14;18)(q32;q21)‐positive FL.
Anthocyanins. III. Disc Sensitivity Assay of Inhibition of Bacterial Growth by Pelargonidin 3‐Monoglucoside and Its Degradation Products a,a, b
Authors: HAMDY MOSTAFA K. , PRATT DAN E. , POWERS JOHN J. , SOMAATMADJA DARDJO
Published: August 2006

Pelargonidin 3‐monoglucoside was isolated from frozen strawberries and subjected to heat degradation in IN HCl. The six fractions isolated were characterized chemically and physically. The unheated and heated pigment inhibited the growth of Escherichia coli and Staphylococcus aureus, and exerted both a stimulatory and inhibitory effect on Lactobacillus casei culture. The stimulation may be due to a decrease in the oxidation‐reduction potential of the media affected by the pigment, and/or the ability of the organism to split the β‐glyeosyl bond and use the glucose moiety. The influence on growth of the test organisms of the various fractions resulting from heating the pigment was reported.
The Volatile Constituents of Passion Fruit Juicea
Authors: HIU DAWES N. , SCHEUER PAUL J.
Published: August 2006

The characteristic flavor of passion fruit was found in the water‐insoluble oil, which constituted ca 36 ppm of the juice. Four components, n‐hexyl caproate, n‐hexyl butyrate, ethyl caproate, and ethyl butyrate, made up ca 95% of the oil, and, among these four, n‐hexyl caproate was found to be the principal component, accounting for ca 70% of the volatile passion fruit essence.

The unidentified portion of the oil (ca. 5%) very likely contains compounds of greater structural complexity than those identified. Evidence for this assumption comes from the appreciable specific rotation of the crude oil. It is also reasonable to assume that the olefinic unsaturation encountered in the crude oil (Table 1) has its origin in the unidentified portion of the oil.
Volatile Esters of Bartlett Pearsa,b
Authors: JENNINGS WALTER G.
Published: August 2006

Esters are responsible for the typical desirable aroma of Bartlett pear. Hydrolysis products of these esters were resolved by gas chromatography. The major ester acid is an unsaturated 10 carbon acid, which hydrogenates to yield n‐capric acid, as identified by relative retention volume and infrared spectroscopy. Nonanoic acid is present in relatively large amounts, and smaller amounts of acetic, propionic, butyric, caproic, and caprylic acids are involved. The major ester alcohols include n‐butyl alcohol and n‐hexyl alcohol. Two other still unidentified alcohols, possibly polyfunctional or cyclic, occur in large amounts. The author was unable to find evidence of ethyl esters.
Growth and Toxin Production by Type E Clostridium Botulinum Below 40°Fa
Authors: SCHMIDT C. F. , LECHOWICH R. V. , FOLINAZZO J. F.
Published: August 2006

Mildly heat‐shocked spores of four strains of Type E Clostridium botulinum (VH, Beluga, Iwanai, and 8E) were inoculated into a heat‐sterilized beef stew substrate and incubated at 34, 36, and 38°F. Inoculum levels of approx 4‐12 million spores per tube were used with different strains. At 38°F, toxin production and visible outgrowth as evidenced by gas formation beneath a vaspar seal occurred in one or more tubes of each of the strains within 31–45 days. No evidence of growth was visible after 14 days at 38°F, and at this time duplicate tubes of each strain were not toxic. After 31 days, strains Iwanai and Beluga showed 2 of 8 tubes with gas and toxin. None of 8 tubes of the VH and 8E strains showed gas after 31 days. Two tubes of each strain were not toxic. After 45 days, tubes of the VH and 8E strains showed visible gas production and toxin. Inoculated tubes incubated at 34 or 36°F showed no gas production during 104 days. Samples of all strains at both temperatures were toxin assayed at 54 days and 104 days, and toxin was absent in all cases. These results suggest a rather sharply defined critical temperature above and below which spores of Type E Cl. botulinum are or are not capable of germinating and initiating toxic outgrowth. The significance of these results in relation to extended refrigerated storage of food products is discussed.
Taste Interrelationships. II. Suprathreshold Solutions of Sucrose and Citric Acid
Authors: PANGBORN ROSE MARIE
Published: August 2006

The effect of citric acid on the sweetness of sucrose solutions was determined by a highly trained panel using variations of two basic methods: single stimulus and paired stimuli. In the former presentation, evaluation of samples singly or in a series of 4 did not alter responses significantly. The binary method, requiring judges to indicate the direction and the degree to which members of a pair differed in sweetness, was slightly more sensitive than the single presentation, especially when one member of the pair within a set was kept constant. The following conclusions were drawn from all methods: (a) Citric acid, at concentrations ranging from 0.007 to 0.073%, depressed the sweetness of 0.5–20.0% sucrose. (b) The masking of sweetness by acid was greater at lower than at higher sucrose concentrations.
The Effect of Storage at Elevated Temperature on Some Proteins of Freeze‐Dried Beefa
Authors: COLE L. J. N.
Published: August 2006

In an attempt to determine the effect of oxygen and elevated temperature on freeze‐dried beef in a moisture‐free atmosphere, two series of storage experiments were conducted on freeze‐dried beef slices. In one longissimus dorsi muscle, and in the other semitendinosus, was packaged under commercially feasible conditions where the residual gas contained 2.5 ± 0.5% oxygen and no atmospheric moisture. An in‐can desiccant, calcium oxide (CaO), and an oxygen scavenger, Oxyban (glucose oxidase), were added in some instances, and the cans were stored up to 6 months at 100°F.

In each series there was marked loss in extractability of actomyosin, and in activity of actomyosin ATPase after 1 month, but only a 40% loss of sarcoplasmic proteins. The residual aldolase activity decreased progressively to 8% at 6 months, whereas the residual water‐soluble proteins decreased progressively only to 56%. There was a marked difference between the two series in percent rehydration at 6 mouths: 81.1 in one, and only 26 in the second. Electrophoresis of the sarcoplasmic proteins showed gross denaturation after 1 month at 100°F.
Composition of Some Subcellular Fractions from Seeds of Arachis hypogaeaa
Authors: DIECKERT JULIUS W. , SNOWDEN JAMES E. , MOORE ANNA T. , HEINZELMAN DOROTHY C. , ALTSCHUL AARON M.
Published: August 2006

Five fractions of parenchymatous cells of the cotyledon of the peanut were isolated by homogenization and differential centrifugation from nonaqueous media. These are two protein‐rich fractions (one of which appears to be aleurone grains), starch grains, a fines material, and cell wall fragments. In addition, a fraction composed largely of vascular tissue of the cotyledon was isolated. The nitrogen of the cell is concentrated in the two protein‐rich fractions, phytin in the aleurone grains, sucrose mostly in the fines fraction and to a lesser extent in the starch granules, and ribonucleic acid in the fines fraction. The proteins in both protein‐rich fractions appear to be the same as judged by chromatography and zone electrophoresis.
Reaction of Cod Actomyosin with Linoleic and Linolenic Acids
Authors: KING FREDERICK J. , ANDERSON MARGARET L. , STEINBERG MAYNARD A.
Published: August 2006

Small concentrations of linoleic and linolenic acids reduced the solubility of cod actomyosin rapidly. The extent of insolubilization depended on the structure of the fatty acid, on its concentration, and on the duration of storage of the fatty‐acid‐treated actomyosin solutions. The results support the hypothesis that the accumulation of free fatty acids in frozen fish muscle causes the actomyosin of the muscle to become inextractable.