bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Plasma Nanomanufacturing Workcell
Authors: Lai King Wai Chiu , Narendra Jeffri J. , Xi Ning , Zhang Jiangbo , Grotjohn Timothy A. , Asmussen Jes
Published: June 2010

Plasma processing is an important technology, which provides a capability to modify the material surface through etching, deposition, activation, functionalization, polymerization, etc. In the current plasma process, the reactive area of the sample is relatively large and thus a mask is needed for selectively treating the sample surface. As a result, the whole fabrication process has become more complicated. In this paper, a plasma integrated nanomanufacturing workcell, which consists of a microplasma source and an integrated atomic force microscopy (AFM) probe tip, has been developed to improve the current plasma apparatus design. The miniature microwave plasma discharge applicator is capable of creating a miniature plasma stream with a diameter ranging from 2 mm down to micrometers. Hence, with the new plasma apparatus it has become possible to locally treat a small area of the sample surface and simplify the fabrication process as the photomask is not required. Additionally, the AFM active probe can be precisely positioned on a desired surface to inspect and manipulate nanoobjects. Here, we report the design and implementation of this new system. Experimental results demonstrate the effectiveness of the system and show that the microplasma can be used in various applications including localized etching of silicon and diamond and localized patterning of photoresist.
Free Vibration Analysis of a Circular Plate With Multiple Circular Holes by Using Indirect BIEM and Addition Theorem
Authors: Lee W. M. , Chen J. T.
Published: June 2010

In this paper, natural frequencies and natural modes of a circular plate with multiple circular holes are theoretically derived and numerically determined by using the indirect boundary integral formulation, the addition theorem, and the complex Fourier series. Owing to the addition theorem, all kernel functions are expanded into degenerate forms and further expressed in the same polar coordinates centered at one circle where the boundary conditions are specified. Not only the computation of the principal value is avoided but also the calculation of higher-order derivatives can be easily determined. By matching boundary conditions, a coupled infinite system of linear algebraic equations is derived as an analytical model for the free vibration of a circular plate with multiple circular holes. The direct-searching approach is utilized in the truncated finite system to determine the natural frequency through singular value decomposition. After determining the unknown Fourier coefficients, the corresponding mode shapes are obtained by using the indirect boundary integral formulations. Some numerical eigensolutions are presented and then utilized to explain some physical phenomenon such as the beating and the dynamic stress concentration. Good accuracy and fast rate of convergence are the main features of the present method, thanks to the analytical approach.
The Onset of Plastic Yielding in a Spherical Shell Compressed by a Rigid Flat
Authors: Li Longqiu , Etsion Izhak , Ovcharenko Andrey , Talke Frank E.
Published: June 2010

The onset of plastic yielding in a spherical shell loaded by a rigid flat is analyzed using finite element analysis. The effect of spherical shell geometry and material properties on the critical normal load, critical interference, and critical contact area, at the onset of plastic yielding, is investigated and the location where plastic yielding first occurs is determined. A universal dimensionless shell parameter, which controls the behavior of the spherical shell, is identified. An empirical relation is found for the load-interference behavior of the spherical shell prior to its plastic yielding. A limiting value of the dimensionless shell parameter is identified above which the shell behaves like a solid sphere.
Safely mounting glass viewports to elastomer sealed vacuum flanges
Authors: Abbott Patrick J. , Scace Brian
Published: June 2010

Elastomer sealed vacuum flanges rely on especially sized elastomer O-rings and corresponding grooves to make an air-tight seal. Depending on the materials being sealed to one another, the O-ring/groove sealing mechanism may be designed for a specific percentage compression of the O-ring at the point of flange-to-flange contact. In the case of a glass viewport being sealed to a metal flange, however, direct contact between the glass and a mating metallic flange may produce stresses in the glass that can lead to failure during system evacuation or while the system is under vacuum. In this article, the authors first review fundamentals of safe O-ring seal construction that the reader will find useful when designing or inspecting viewports meant for vacuum systems. We then discuss an especially constructed adapter flange that allows the safe sealing of a 20 cm diameter glass viewport to an aluminum O-ring flange that was originally designed for a typical metal flange-to-metal flange seal. Factors affecting the strength of glass are discussed, and calculations for maximum deflection under load and safe glass window thickness are presented.
Sensitivity enhancement in hydrogen permeation measurements
Authors: Nemanič Vincenc , Zajec Bojan , Žumer Marko
Published: June 2010

Permeation of hydrogen isotopes from the upstream pressure through a membrane into high vacuum at elevated temperatures is a challenging task for vacuum technology, especially when very low fluxes must be determined. Geometrical and mechanical constraints set an engineering issue since the ultimate tightness of the seals at high temperature must be preserved. Recording the steady permeation flux and its transients requires high sensitivity and stability of the gauges. It is anyhow far more challenging to suppress the hydrogen background outgassing flux to the level when it represents only a fraction of the permeation flux. The authors present an innovative permeation cell design that results in efficient hydrogen background suppression. When implemented in an all-metal UHV system, low permeation flux density of hydrogen down to j∼10−9 mbar L/(cm2 s) could be measured on disk-shaped membranes having an area of 8.4 cm2.
Thickness inhomogeneities and growth mechanisms of GaP heteroepitaxy by organometallic chemical vapor deposition
Authors: Liu X. , Aspnes D. E.
Published: June 2010

The authors report comparative studies of the deposition of GaP on (001) GaAs, as-polished (001)Si, SiO2-coated (001)Si, nanoscopically roughened (001)Si, and polycrystalline GaP surfaces by organometallic chemical vapor deposition using trimethylgallium (TMG) and phosphine (PH3) sources. The thicknesses of the GaP films increase or decrease exponentially toward the edge of wafers. This functional dependence implies one-dimensional gas-phase diffusion of a reactive species, possibly H–P=Ga–CH3, generated by heterogeneous catalysis according to the reactivity of the different surfaces to the decomposition of PH3. Deposition on (001)Si depends on the type of nanoscopic roughness of the substrate.
Epitaxial growth and chemical lift-off of GaInN/GaN heterostructures on c- and r-sapphire substrates employing ZnO sacrificial templates
Authors: Liu H. F. , Liu W. , Chua S. J.
Published: June 2010

The authors report epitaxial growth of GaInN/GaN heterostructures on ZnO/c-sapphire and ZnO/r-sapphire substrates by using metal-organic chemical-vapor deposition and chemical lift-off by etching away the ZnO templates. Using a black-wax technique and a vapor wax-elimination method, they demonstrate a 10×10 mm2 crack-free lift-off of GaInN/GaN from the c-sapphire substrate followed by bonding to a glass holder. On the ZnO/r-sapphire substrate, with the same lift-off processing, the GaInN/GaN was regularly cracked along its c-axis and the cracking is independent of the etching rate (controlled by the solution density). The cracking mechanism is investigated and discussed based on the x-ray diffraction and Raman-scattering characterizations before and after lift-off.
Growth, electrical, and optical properties of nanocrystalline VO2 (011) thin films prepared by thermal oxidation of magnetron sputtered vanadium films
Authors: Luo Zhenfei , Wu Zhiming , Xu Xiangdong , Wang Tao , Jiang Yadong
Published: June 2010

Nanocrystalline vanadium dioxide (VO2) thin films were prepared on glass substrates at different deposition temperatures by oxidizing sputtered vanadium films. Atomic force microscope, x-ray diffraction, and Raman scattering were employed to characterize the films. It was confirmed that low deposition temperature resulted in improving oxygen atom diffusion and VO2 nanograin growth in the thermal oxidation process. Investigation of the electrical properties revealed that the amplitude of semiconductor-metal transition and transition temperature decreased, whereas the Hall mobility and carrier concentration increased as the deposition temperature elevated. Optical investigations were carried out in the ultraviolet-visible-near-infrared region. Narrow optical band gaps were observed in these films.
Hot-Electron Transfer from Semiconductor Nanocrystals
Authors: Tisdale William A. , Williams Kenrick J. , Timp Brooke A. , Norris David J. , Aydil Eray S. , Zhu X.-Y.
Published: June 2010

Hot on the Trail

Solar cells essentially operate by absorbing light, which needs to be above a certain energy threshold. The absorbed light then liberates charges within the solar cell to carry electrical current. Unfortunately, the liberated charges behave the same way whether they are excited right at the threshold (e.g., by visible light) or well above it (by ultraviolet light), which leads to any excess energy being dissipated as waste heat.

Tisdale
et al.

(p.
1543
) have documented a potential first step toward resolving this inefficiency. Specifically, electrons excited by light absorption in lead selenide nanocrystals were able to migrate to an adjacent titanium dioxide surface without releasing their excess energy to heat. The next step will be to devise a means of harnessing the stored energy in a circuit.
How Do Polar Marine Ecosystems Respond to Rapid Climate Change?
Authors: Schofield Oscar , Ducklow Hugh W. , Martinson Douglas G. , Meredith Michael P. , Moline Mark A. , Fraser William R.
Published: June 2010

Climate change will alter marine ecosystems; however, the complexity of the food webs, combined with chronic undersampling, constrains efforts to predict their future and to optimally manage and protect marine resources. Sustained observations at the West Antarctic Peninsula show that in this region, rapid environmental change has coincided with shifts in the food web, from its base up to apex predators. New strategies will be required to gain further insight into how the marine climate system has influenced such changes and how it will do so in the future. Robotic networks, satellites, ships, and instruments mounted on animals and ice will collect data needed to improve numerical models that can then be used to study the future of polar ecosystems as climate change progresses.
Sea-Level Rise and Its Impact on Coastal Zones
Authors: Nicholls Robert J. , Cazenave Anny
Published: June 2010

Global sea levels have risen through the 20th century. These rises will almost certainly accelerate through the 21st century and beyond because of global warming, but their magnitude remains uncertain. Key uncertainties include the possible role of the Greenland and West Antarctic ice sheets and the amplitude of regional changes in sea level. In many areas, nonclimatic components of relative sea-level change (mainly subsidence) can also be locally appreciable. Although the impacts of sea-level rise are potentially large, the application and success of adaptation are large uncertainties that require more assessment and consideration.
Comment on “Deep-Sea Temperature and Ice Volume Changes Across the Pliocene-Pleistocene Climate Transitions”
Authors: Yu Jimin , Broecker Wally S.
Published: June 2010

Sosdian and Rosenthal (Reports, 17 July 2009, p. 306) used magnesium/calcium ratios in benthic foraminifera from the North Atlantic to reconstruct past bottom-water temperatures. They suggested that both ice volume change and ice-sheet dynamics played important roles during the late Pliocene and mid-Pleistocene climate transitions. We present evidence that their record of deep ocean temperature is not reliable, thus raising doubts about their conclusions.
Development of the Spatial Representation System in the Rat
Authors: Langston Rosamund F. , Ainge James A. , Couey Jonathan J. , Canto Cathrin B. , Bjerknes Tale L. , Witter Menno P. , Moser Edvard I. , Moser May-Britt
Published: June 2010

The Space in Your Head

Space, and events associated with places and spaces, are represented in the brain by a circuitry made of place cells, head direction cells, grid cells, and border cells. These cell types form a collective dynamic representation of our position as we move through the environment. How this representation is formed has remained a mystery. Is it acquired, or are we born with the ability to represent external space (see the Perspective by

Palmer and Lynch

)?

Langston
et al.

(p.
1576
) and

Wills
et al.

(p.
1573
) investigated the early development of spatial activity in the hippocampal formation and the entorhinal cortex of rat pups when they first began to explore their environment. Rudiments of place cells, head direction cells, and grid cells already existed when the pups made their first movements out of the nest. A neural representation of external space at this early time points to strong innate components for perception of space. These findings provide experimental support for Kant's 200-year-old concept of space as an a priori faculty of the mind.
Development of the Hippocampal Cognitive Map in Preweanling Rats
Authors: Wills Tom J. , Cacucci Francesca , Burgess Neil , O'Keefe John
Published: June 2010

The Space in Your Head

Space, and events associated with places and spaces, are represented in the brain by a circuitry made of place cells, head direction cells, grid cells, and border cells. These cell types form a collective dynamic representation of our position as we move through the environment. How this representation is formed has remained a mystery. Is it acquired, or are we born with the ability to represent external space (see the Perspective by

Palmer and Lynch

)?

Langston
et al.

(p.
1576
) and

Wills
et al.

(p.
1573
) investigated the early development of spatial activity in the hippocampal formation and the entorhinal cortex of rat pups when they first began to explore their environment. Rudiments of place cells, head direction cells, and grid cells already existed when the pups made their first movements out of the nest. A neural representation of external space at this early time points to strong innate components for perception of space. These findings provide experimental support for Kant's 200-year-old concept of space as an a priori faculty of the mind.
Evolutionary Novelty Is Concentrated at the Edge of Coral Species Distributions
Authors: Budd Ann F. , Pandolfi John M.
Published: June 2010

Don't Forget the Edges

Reef-building corals are highly diverse, and many are threatened with extinction. In order to make predictions about coral survival,
Budd and Pandolfi
(p.
1558
) examined morphological changes occurring over the evolutionary history of Caribbean corals. Long-term evolutionary patterns, including hybridization between species and diversification into new species (so-called lineage fusion and splitting) differed depending on the geographical location within the colony, with higher change occurring at a species' geographic margin relative to those in central locations. Thus, edge zones, which often experience limited gene flow, are responsible for the predominance of evolutionary innovation. If conservation strategies are biased toward biodiversity hotspots, which represent centers of high species richness, they may miss important sources of evolutionary novelty during global change.
Bose-Einstein Condensation in Microgravity
Authors: van Zoest T. , Gaaloul N. , Singh Y. , Ahlers H. , Herr W. , Seidel S. T. , Ertmer W. , Rasel E. , Eckart M. , Kajari E. , Arnold S. , Nandi G. , Schleich W. P. , Walser R. , Vogel A. , Sengstock K. , Bongs K. , Lewoczko-Adamczyk W. , Schiemangk M. , Schuldt T. , Peters A. , Könemann T. , Müntinga H. , Lämmerzahl C. , Dittus H. , Steinmetz T. , Hänsch T. W. , Reichel J.
Published: June 2010

Going Down the Tube

Two pillars of modern physics are quantum mechanics and general relativity. So far, both have remained apart with no quantum mechanical description of gravity available.

Van Zoest
et al.

(p.
1540
; see the Perspective by

Nussenzveig and Barata

) present work with a macroscopic quantum mechanical system—a Bose-Einstein condensate (BEC) of rubidium atoms in which the cloud of atoms is cooled into a collective quantum state—in microgravity. By dropping the BEC down a 146-meter-long drop chamber and monitoring the expansion of the quantum gas under these microgravity conditions, the authors provide a proof-of-principle demonstration of a technique that can probe the boundary of quantum mechanics and general relativity and perhaps offer the opportunity to reconcile the two experimentally.
The Impact of Climate Change on the World’s Marine Ecosystems
Authors: Hoegh-Guldberg Ove , Bruno John F.
Published: June 2010

Marine ecosystems are centrally important to the biology of the planet, yet a comprehensive understanding of how anthropogenic climate change is affecting them has been poorly developed. Recent studies indicate that rapidly rising greenhouse gas concentrations are driving ocean systems toward conditions not seen for millions of years, with an associated risk of fundamental and irreversible ecological transformation. The impacts of anthropogenic climate change so far include decreased ocean productivity, altered food web dynamics, reduced abundance of habitat-forming species, shifting species distributions, and a greater incidence of disease. Although there is considerable uncertainty about the spatial and temporal details, climate change is clearly and fundamentally altering ocean ecosystems. Further change will continue to create enormous challenges and costs for societies worldwide, particularly those in developing countries.
Proposed U.S. Policy for Ocean, Coast, and Great Lakes Stewardship
Authors: Lubchenco Jane , Sutley Nancy
Published: June 2010

Regional planning bodies would implement coordinated, ecosystem-based approaches to coastal and marine spatial planning.
Paring MiRNAs Through Pairing
Authors: Pasquinelli Amy E.
Published: June 2010

The extent of base-pairing between a microRNA and RNA affects both RNA translation and stability of the microRNA itself.
A Drop of Quantum Matter
Authors: Nussenzveig Paulo , Barata João C. A.
Published: June 2010

Studies of a quantum object—a Bose-Einstein condensate—in free-fall conditions may provide high-precision tests of general relativity.
Fusion 'Consolation Prize' Gears Up for Show Time
Authors: Normile Dennis
Published: June 2010

A unique particle accelerator and the fastest supercomputer in Japan are part of a plan to bring fusion energy a step closer to reality. They are proceeding in parallel with the single most important experiment for the future of fusion power, the $12 billion International Thermonuclear Experimental Reactor.
Probing the Secrets of the Finest Fiddles
Authors: Cho Adrian
Published: June 2010

Violinmakers are taking up the tools of science in a study of Guarneri del Gesù's Vieuxtemps and other great violins.
The Invisible Hand Behind A Vast Carbon Reservoir
Authors: Stone Richard
Published: June 2010

A key element of the carbon cycle is the microbial conversion of dissolved organic carbon into inedible forms. Can it also serve to sequester CO
2
?
Blocking Effect of a Monoclonal Antibody against Recombinant Pvs25 on Sporozoite Development in
Anopheles sinensis
Authors: Moon Sung-Ung , Kim Hyung-Hwan , Kim Tong-Soo , Choi Kyung-Mi , Oh Chang-Mi , Ahn Yong-Joo , Hwang Seo-Kyoung , Sohn Youngjoo , Shin E-Hyun , Kim Hyuck , Lee Hyeong-Woo
Published: June 2010

To develop a vaccine to block the transmission of vivax malaria, the gene encoding the ookinete surface protein Pvs25 was cloned from a Korean malaria patient. The
Pvs25
gene was 660 bp long, encoding 219 amino acids. It was subcloned into the expression vector pQE30 and expressed in
Escherichia coli
. The expressed recombinant protein, named rPvs25, showed a molecular mass of approximately 25 kDa by SDS-PAGE analysis. An anti-rPvs25 monoclonal antibody produced in BALB/c mice was able to inhibit sporozoite development in the mosquito
Anopheles sinensis
, which is known as the malaria transmission vector in the Republic of Korea. In addition, rPvs25 produced a relatively high antibody titer in BALB/c mice that lasted for more than 6 months. Based on these results, we suggest that recombinant Pvs25 could be a useful antigen in the development of a vaccine to prevent local malaria transmission in the Republic of Korea.
A Large Study on Immunological Response to a Whole-Cell Killed Oral Cholera Vaccine Reveals That There Are Significant Geographical Differences in Response and That O Blood Group Individuals Do Not Elicit a Higher Response
Authors: Ramamurthy T. , Wagener Diane , Chowdhury Goutam , Majumder Partha P.
Published: June 2010

The ABO blood group system has been implicated in susceptibility to cholera or in explaining variability in the immune response to a cholera vaccine. O blood group individuals were found to be more susceptible to cholera and elicited lower vibriocidal antibody response to cholera toxin B subunit-killed oral vaccine. Based on the observations that O blood group individuals were more susceptible to cholera and that high mortality was associated with cholera, an evolutionary explanation was provided for the extremely low prevalence of the O blood group in the Gangetic Delta (West Bengal, India, and Bangladesh). However, conflicting results were reported from a later study conducted in Indonesia using a live attenuated oral cholera vaccine; O blood group individuals showed a higher vibriocidal antibody response. In a study conducted in a region of India where cholera is endemic (Kolkata, West Bengal) that comprised 992 individuals vaccinated by a killed whole-cell oral cholera vaccine, we found no statistically significant difference between O and non-O individuals either in the frequency distributions of the fold increase or in the postvaccination increase in geometric mean titer compared to the baseline. Further, in contrast to the earlier observation that the O allele frequency is extremely low in the Gangetic Delta, we have noted that the O allele frequency exceeds 0.5 in the vast majority of ethnic groups of this region. In addition, we have found large differences in response to the vaccine among residents of an area where cholera is not endemic compared to an area where cholera is endemic to The percentages of vaccinees who seroconverted in an area where cholera is not endemic (Son La province of Vietnam) was >90% compared to ∼50% in Kolkata, India, an area where cholera is endemic.
Mobilization of CD34
+
Progenitor Cells in Association with Decreased Proliferation in the Bone Marrow of Macaques after Administration of the Fms-Like Tyrosine Kinase 3 Ligand
Authors: Reeves R. Keith , Wei Qing , Fultz Patricia N.
Published: June 2010

Fms-like tyrosine kinase 3 ligand (FLT3-L) is critical for the differentiation and self-renewal of CD34
+
progenitor cells in primates and has been used therapeutically to mobilize progenitor and dendritic cells
in vivo
. However, little is known regarding the expansion of progenitor cells outside of peripheral blood, particularly in bone marrow (BM), where progenitor cells primarily reside. Evaluation of FLT3-L-mediated cell mobilization during lentivirus infections, where the numbers of CD34
+
progenitor cells are reduced, is limited. We enumerated frequencies and absolute numbers of CD34
+
progenitor cells in blood and BM of naive and SIV- or SHIV-infected macaques during and after the administration of FLT3-L. Flow cytometric analyses revealed that, while CD34
+
cells increased in the circulation, no expansion was observed in BM. Furthermore, in the BM intracellular Ki67, a marker of cell proliferation, was downregulated in CD34
+
progenitor cells but was upregulated significantly in the bulk cell population. Although the exact mechanism(s) remains unclear, these data suggest that CD34
+
cell mobilization in blood was the result of cellular emigration from BM and not the proliferation of CD34
+
cells already in the periphery. It is possible that the decreased progenitor cell proliferation observed in BM is evidence of a negative regulatory mechanism preventing hyperproliferation and development of neoplastic cells.
Comparison of an Automated Repetitive-Sequence-Based PCR Microbial Typing System with Pulsed-Field Gel Electrophoresis for Molecular Typing of Vancomycin-Resistant
Enterococcus faecium
Authors: Chuang Yu-Chung , Wang Jann-Tay , Chen Mei-Ling , Chen Yee-Chun
Published: June 2010

Vancomycin-resistant
Enterococcus faecium
(VRE) has become an important health care-associated pathogen because of its rapid spread, limited therapeutic options, and possible transfer of vancomycin resistance to more-virulent pathogens. In this study, we compared the ability to detect clonal relationships among VRE isolates by an automated repetitive-sequence-based PCR (Rep-PCR) system (DiversiLab system) to pulsed-field gel electrophoresis (PFGE), the reference method for molecular typing of VRE. Two sets of VRE isolates evaluated in this study were collected by active microbial surveillance at a large teaching hospital in Taiwan during 2008. The first set included 90 isolates randomly selected from the surveillance cohort. The first set consisted of 34 pulsotypes and 10 Rep-PCR types. There was good correlation between the two methods (
P
< 0.001). The second set included 68 VRE isolates collected from eight clusters of colonization. A dominant clone was detected in five out of eight clusters by both methods. Two clusters were characterized by Rep-PCR as being caused by a dominant clone, whereas PFGE showed polyclonal origins. One cluster was shown to be polyclonal by both methods. A single Rep-PCR clone type was detected among 12 of 14 vancomycin-intermediate enterococci, whereas PFGE detected six pulsotypes. In conclusion, the Rep-PCR method correlated well with PFGE typing but was less discriminative than PFGE in defining clonal relationships. The ease of use and more rapid turnaround time of Rep-PCR compared to PFGE offers a rapid screening method to detect outbreaks of VRE and more rapidly implement control measures. PFGE remains the preferred method to confirm clonal spread.
Rapid Genus- and Species-Specific Identification of
Cronobacter
spp. by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry
Authors: Stephan Roger , Ziegler Dominik , Pflüger Valentin , Vogel Guido , Lehner Angelika
Published: June 2010

Cronobacter
spp. are Gram-negative opportunistic food-borne pathogens and are known as rare but important causes of life-threatening neonatal infections. Rapid and reliable identification of
Cronobacter
species and their differentiation from phenotypically similar, nonpathogenic
Enterobacter turicensis
,
Enterobacter helveticus
, and
Enterobacter pulveris
have become increasingly important. We evaluated here the application of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for rapid genus and species identification of the six
Cronobacter
species recognized so far. To this end, we developed a reference MS database library that includes 54
Cronobacter
target strains as well as 17 nontarget strains. The strains provided reproducible and unique mass spectra profiles covering a wide molecular mass range (2,000 to 30,000 Da). Genus- and species-specific biomarker protein mass patterns were determined. The defined biomarker mass patterns (Spectral Archive and Microbial Identification System [SARAMIS] SuperSpectrum) were validated using 36 strains from various
Cronobacter
species as well as eight nontarget strains. For all strains the mass spectrometry-based identification scheme yielded identical results as with a PCR-based identification system. All strains were correctly identified, and no nontarget strain was misidentified as
Cronobacter
. Our study demonstrates that MALDI-TOF MS is a reliable and powerful tool for the rapid identification of
Cronobacter
strains to the genus and species level.
Comparative Analysis of Rabies Virus Reverse Transcription-PCR and Virus Isolation Using Samples from a Patient Infected with Rabies Virus
Authors: Panning Marcus , Baumgarte Sigrid , Pfefferle Susanne , Maier Tanja , Martens Andreas , Drosten Christian
Published: June 2010

Definite and rapid diagnosis of rabies is required for individual case management as well as for public health. For the first time, a direct comparison of virus isolation with quantitative real-time reverse transcription (RT)-PCR on human rabies samples was conducted. RT-PCR was found to be more sensitive than virus isolation.
Validation of a Rapid Immunochromatographic Assay for Diagnosis of
Trypanosoma cruzi
Infection among Latin-American Migrants in Geneva, Switzerland
Authors: Chappuis François , Mauris Anne , Holst Marylise , Albajar-Vinas Pedro , Jannin Jean , Luquetti Alejandro O. , Jackson Yves
Published: June 2010

Chagas' disease is a global public health problem due to the recent exchange of population between Latin America and other regions, including Europe. The recent development of rapid diagnostic tests (RDTs) for
Trypanosoma cruzi
infection may improve patient access to diagnosis and care worldwide. We evaluated the diagnostic accuracy of the Chagas Stat-Pak RDT in a cohort of undocumented Latin-American migrants living in Geneva, Switzerland. Study participants were enrolled in a primary health care center. The Chagas Stat-Pak test was performed independently on blood and serum samples. A combination of two commercialized enzyme-linked immunosorbent assay (ELISA)-based serological tests was used for comparison (reference standard). A total of 999 adults (median age, 36 years) were included in the study; the majority were women (83%) and originally from Bolivia (47%) or Brazil (25%). A total of 125 participants (12.5%) were diagnosed with
T. cruzi
infection; with the exception of three individuals, all individuals diagnosed with
T. cruzi
were originally from Bolivia. The sensitivity and specificity of the Chagas Stat-Pak test on blood samples were 95.2% (95% confidence interval [95% CI], 89.2% to 97.9%) and 99.9% (95% CI, 99.3% to 100%), respectively. When the test was performed on serum samples, the sensitivity was 96% (95% CI, 91% to 98.3%), and the specificity was 99.8% (95% CI, 99.2% to 99.9%). The concordance of test results for blood and serum samples was 99.7%. Both negative and positive predictive values were above 98%. The Chagas Stat-Pak is an accurate diagnostic test for
T. cruzi
infection among Latin-American migrants living in Europe. The mild deficit in sensitivity should be interpreted in light of its ease of use and capacity to provide immediate results, which allow more people at risk to have access to diagnosis and care both in countries where Chagas' disease is endemic and in countries where this disease is not endemic.
Functional Properties of the Human Cytomegalovirus IE86 Protein Required for Transcriptional Regulation and Virus Replication
Authors: Harris Siabhon M. , Bullock Brady , Westgard Elizabeth , Zhu Hua , Stenberg Richard M. , Kerry Julie A.
Published: June 2010

The human cytomegalovirus (HCMV) IE86 protein is essential for HCMV replication due to its ability to transactivate critical viral early promoters. In the current study, we performed a comprehensive mutational analysis between amino acids (aa) 535 and 545 of IE86 and assessed the impact of these mutations on IE86-mediated transcriptional activation. Using transient assays and complementing analysis with recombinant HCMV clones, we show that single amino acid mutations differentially impair the ability of IE86 to mediate transactivation of essential early gene promoters. The conserved tyrosine at amino acid 544 is critical for activation of the UL54 promoter
in vitro
and in the context of the viral genome. In contrast, mutation of the proline at position 535 disrupted activation of the UL54 promoter in transient assays but displayed activity similar to that of wild-type (WT) IE86 when assessed in the genomic context. To examine the underlying mechanism of this differential effect, glutathione
S
-transferase (GST) pulldown assays were performed, revealing that Y544 is critical for binding to the TATA binding protein (TBP), suggesting that this interaction is likely necessary for the ability of IE86 to activate the UL54 promoter. In contrast, mutation of either P535 or Y544 disrupted activation of the UL112-113 promoter both
in vitro
and
in vivo
, suggesting that interaction with TBP is not sufficient for IE86-mediated activation of this early promoter. Together, these studies demonstrate that IE86 activates early promoters by distinct mechanisms.
Interaction of α
V
β
3
and α
V
β
6
Integrins with Human Parechovirus 1
Authors: Seitsonen Jani , Susi Petri , Heikkilä Outi , Sinkovits Robert S. , Laurinmäki Pasi , Hyypiä Timo , Butcher Sarah J.
Published: June 2010

Human parechovirus (HPEV) infections are very common in early childhood and can be severe in neonates. It has been shown that integrins are important for cellular infectivity of HPEV1 through experiments using peptide blocking assays and function-blocking antibodies to α
V
integrins. The interaction of HPEV1 with α
V
integrins is presumably mediated by a C-terminal RGD motif in the capsid protein VP1. We characterized the binding of integrins α
V
β
3
and α
V
β
6
to HPEV1 by biochemical and structural studies. We showed that although HPEV1 bound efficiently to immobilized integrins, α
V
β
6
bound more efficiently than α
V
β
3
to immobilized HPEV1. Moreover, soluble α
V
β
6
, but not α
V
β
3
, blocked HPEV1 cellular infectivity, indicating that it is a high-affinity receptor for HPEV1. We also showed that HPEV1 binding to integrins
in vitro
could be partially blocked by RGD peptides. Using electron cryo-microscopy and image reconstruction, we showed that HPEV1 has the typical T=1 (pseudo T=3) organization of a picornavirus. Complexes of HPEV1 and integrins indicated that both integrin footprints reside between the 5-fold and 3-fold symmetry axes. This result does not match the RGD position predicted from the coxsackievirus A9 X-ray structure but is consistent with the predicted location of this motif in the shorter C terminus found in HPEV1. This first structural characterization of a parechovirus indicates that the differences in receptor binding are due to the amino acid differences in the integrins rather than to significantly different viral footprints.
Phylogeny-Based Evolutionary, Demographical, and Geographical Dissection of North American Type 2 Porcine Reproductive and Respiratory Syndrome Viruses
Authors: Shi Mang , Lam Tommy Tsan-Yuk , Hon Chung-Chau , Murtaugh Michael P. , Davies Peter R. , Hui Raymond Kin-Hei , Li Jun , Wong Lina Tik-Wim , Yip Chi-Wai , Jiang Jin-Wai , Leung Frederick Chi-Ching
Published: June 2010

Type 2 (or North American-like) porcine reproductive and respiratory syndrome virus (PRRSV) was first recorded in 1987 in the United States and now occurs in most commercial swine industries throughout the world. In this study, we investigated the epidemiological and evolutionary behaviors of type 2 PRRSV. Based on phylogenetic analyses of 8,624 ORF5 sequences, we described a comprehensive picture of the diversity of type 2 PRRSVs and systematically classified all available sequences into lineages and sublineages, including a number of previously undescribed lineages. With the rapid growth of sequence deposition into the databases, it would be technically difficult for veterinary researchers to genotype their sequences by reanalyzing all sequences in the databases. To this end, a set of reference sequences was established based on our classification system, which represents the principal diversity of all available sequences and can readily be used for further genotyping studies. In addition, we further investigated the demographic histories of these lineages and sublineages by using Bayesian coalescence analyses, providing evolutionary insights into several important epidemiological events of type 2 PRRSV. Moreover, by using a phylogeographic approach, we were able to estimate the transmission frequencies between the pig-producing states in the United States and identified several states as the major sources of viral spread, i.e., “transmission centers.” In summary, this study represents the most extensive phylogenetic analyses of type 2 PRRSV to date, providing a basis for future genotyping studies and dissecting the epidemiology of type 2 PRRSV from phylogenetic perspectives.
Ion solvation by dipolar aprotic solvents. An ab initio study
Authors: Kyselka Petr , Havlas Zdeněk , Sláma Ivo
Published: June 2010

The paper deals with the solvation of Li+, Be2+, Na+, Mg2+, and Al3+ ions in dimethyl sulphoxide, dimethylformamide, acetonitrile, and water. The ab initio quantum chemical method was used to calculate the solvation energies, molecular structures, and charge distributions for the complexes water···ion, acetonitrile···ion, dimethyl sulphoxide···ion, and dimethylformamide···ion. The interaction energies were corrected for the superposition error. Complete geometry optimization was performed for the complex water···ion. Some generalizations are made on the basis of the results obtained.
Solvent effects on the infrared intensities of the ν2, ν4, and ν9 bands of 1,1-dichloroethylene
Authors: Hensel Thomas , Fruwert Johanna , Dathe Klaus
Published: June 2010

The infrared intensities of the ν2, ν4, and ν9 stretching bands of 1,1-dichloroethylene have been measured in eighteen solvents of different polarity. After correcting for the local field effect, the partial derivatives of the electric dipole moment and electric polarizability with respect to normal coordinates were calculated using the dipole-dipole interaction model. A good or a poor statistical correlation of the calculated and observed intensities then indicates whether this model is adequate or other phenomena are involved in the interaction.
The effect of titanium and sodium in alumina on its acidic and catalytic properties
Authors: Jirátová Květa , Roček Josef
Published: June 2010

Acidic and catalytic properties of alumina containing small amounts of Ti(IV) and Na(I) (up to 1 wt.% of both) were examined. It has been proved that the amount of acid sites with the strength H0 ⪬ 3.3 and the initial reaction rates of cyclohexene isomerization depend linearly on calculated total electronegativity of the corresponding mixture of oxides.
Anodic voltammetry of pyrazolone derivatives with the help of the self-cleaning rotating electrode
Authors: Noninski Vesselin C. , Sobowale Emanuel B.
Published: June 2010

Nine pyrazolone derivatives have been studied by anodic voltammetry using gold self-cleaning rotating electrode (SRE). Voltamograms of good reproducibility are presented. On the basis of voltammetric data a mechanism is proposed for the electrochemical oxidation of sodium 1-phenyl-2,3-dimethyl-4-(N-methylamino)pyrazol-5-one-N-methansulphonate and 1-phenyl-2,3-dimethyl-4-(dimethylamino)pyrazol-5-one in protic medium.
Mixed suspension - mixed product removal crystallization kinetics: Effect of the method of supersaturation generation
Authors: Žáček Stanislav , Nývlt Jaroslav , Mullin John William
Published: June 2010

Three methods of continuous crystallization of potassium aluminium sulphate have been compared: crystallization by cooling, precipitation from solutions of component salts (potassium sulphate and aluminium sulphate) and salting-out with ethanol. Crystal size distribution of the products has been used to obtain crystallization kinetic data in two parallel ways, viz. using the concept of population balance and that of mass oversize distribution, both of which led to similar conclusions. The results of cooling and precipitation are comparable, but crystallization by salting-out with ethanol leads to smaller crystals and the results strongly depend on the alcohol concentration, which can be explained by the influence of micromixing.
Effect of crystallographic orientation on the kinetics of reaction of aluminium single crystal in aqueous solution of sodium hydroxide
Authors: Miadoková Milica , Plchová Magdalena , Halaša Ivan
Published: June 2010

The effect of the concentration of OH- ions, oxygen pressure, and temperature on the rate of reaction of aluminium in aqueous solution of sodium hydroxide was studied for surface planes corresponding to the (100), (110), and (111) crystallographic planes. Kinetic anisotropy was observed: the reaction rate increased and the apparent activation energy decreased in order (100)-(110)-(111). The kinetic parameters were related to some physical characteristics of the surface.
Arachno-6,9-C2B8H14 dicarbaborane and its 1- and 5-monohalogenated derivatives
Authors: Štíbr Bohumil , Janoušek Zbyněk , Plešek Jaromír , Jelínek Tomáš , Heřmánek Stanislav
Published: June 2010

Reduction of nido-5,6-C2B8H12 with sodium tetrahydroborate in ethanolic sodium hydroxide as a new method for preparing arachno-6,9-C2B8H14 is reported. Electrophilic halogenation of 6,9-C2B8H14 occurs at the B(1) site to give a series of 1-X-6,9-C2B8H13 (X = Cl, Br, and I) derivatives. Stereoselective addition of hydrogen halides to the B(5)-C(6) bond in the [6,9-C2B8H10]2- anion results in the formation of 5-X-6,9-C2B8H13 (X = F, Cl, Br, I and 5'-0-6,9-C2B8H13) compounds. Constitution of all compounds isolated is suggested on the basis of their 1H and 11B NMR data and the effects of halogen substituents on the 11B NMR shielding of individual cage boron atoms are discussed in terms of Δδ and k2 values.
Mechanism of the reaction of 1-methoxy- and 1-chloro-2,4,6-trinitrobenzene with dimethyl malonate anion
Authors: Macháček Vladimír , Štěrba Vojeslav , Lyčka Antonín
Published: June 2010

1H NMR spectra have been used to prove the formation of 1,3- and 1,1-adducts in the reaction of 1-methoxy-2,4,6-trinitrobenzene with dimethyl malonate anion and formation of 1,3-adduct in the analogous reaction of 1-chloro-2,4,6-trinitrobenzene. Dimethyl 2,4,6-trinitrophenylmalonate is formed from 1-chloro-2,4,6-trinitrobenzene at the same rate and by the same mechanism as the 1,1-adduct from 1-methoxy-2,4,6-trinitrobenzene. The two reactions only differ in their rate-limiting steps.
Study of the reactivity of 2-(3-chlorobenzylidene)[3]ferrocenophane-1,3-dione
Authors: Kaliská Viera , Sališová Marta , Solčániová Eva , Toma Štefan
Published: June 2010

The addition of different C-nucleophiles to 2-(3-chlorobenzylidene)[3]ferrocenophane-1,3-dione has been studied. In most cases, the addition has led to expansion of the strained 3-membered bridge to the 7-membered one. An analogous bridge expansion has been observed also in the reaction of 2-(4-chlorobenzylidene)[3]ferrocenophane-1,3-dione with 1,3-cyclohexanedione. 2-(3-chlorobenzylidene)[3]ferrocenophane-1,3-dione reacts with vinyl ethyl ether as a heterodiene, yielding the 4 + 2 cycloadduct.
Michael additions to metallocene analogues of chalcones
Authors: Federič Jozef , Toma Štefan
Published: June 2010

Eleven analogues of chalcones were synthesized; the variously substituted ferrocenyl, ruthenocenyl or η5-cyclopentadienyltricarbonylmanganese are attached to the β-carbon of the chalcone double bond. Methyl malonate was added to eight selected chalcones. The effect of an aryl group on the chemical shift difference of diastereotopic -COOCH3 groups is discussed. The Vilsmeier-Haack formylation was employed to prepare 1'-chloro and 1'-bromoferrocenecarbaldehydes. The synthesis of 2-chloroferrocenecarbaldehyde from 2-chloroferrocenylmethyldimethylamine is also described.
Preparation of 2,2,6,6-tetramethyl-4-aminopiperidine and its substituted compounds by electroreduction of azomethines of 2,2,6,6-tetramethyl-4-oxopiperidine (triacetonamine)
Authors: Fioshin M. Ya. , Avrutskaya I. A. , Surov I. I. , Novikov V. T.
Published: June 2010

Five methods have been developed for electrosynthesis of 2,2,6,6-tetramethyl-4-aminopiperidine in 95-98% yield via the lead-cathode reduction of 2,2,6,6-tetramethyl-4-oxiimino-piperidine, a mixture of triacetonamine with inorganic salts of hydroxylamine, and a mixture of triacetonamine with nitric acid in a solution of sulphuric acid, via the reduction of azine triacetonamine and of a mixture of triacetonamine with inorganic salts of hydrazine in a neutral solution. The corresponding saturated derivatives of 2,2,6,6-tetramethyl-4-aminopiperidine have been obtained in 60-80% yield by electroreduction of phenylimine and ethylene diimine.
Sulphonates and carboxylates of (E)- and (Z)-3-(hydroxymethylene)-trans-hexahydro-2(3H)-benzofuranone
Authors: Mazal Ctibor , Jonas Jaroslav
Published: June 2010

Sodium salt of 3-(hydroxymethylene)-trans-hexahydro-2(3H)-benzofuranone has been found to be formed as the (Z)-isomer in solid state and to exist as the (E)-isomer or a mixture of the both isomers in polar solvents. Some sulphonates and carboxylates of (E)-3-(hydroxymethylene)-trans-hexahydro-2(3H)-benzofuranone and (Z)-3-(hydroxymethylene)-trans-hexahydro-2(3H)-benzofuranone have been prepared by reactions of the corresponding isomers of this sodium salt with sulphonyl and acyl chlorides, respectively. The configuration of the isomeric derivatives was confirmed by 1H and 13C NMR spectra.
Measurement of vapour-liquid equilibrium data of liquids with low vapour pressure
Authors: Surový Július , Graczová Elena , Dojčanský Ján
Published: June 2010

A semimicrostill for measuring vapour-liquid equilibrium data suitable especially for the determination at pressures about 100 Pa is described. The still operates isothermally on the principle of differential distillation. The composition of equilibrium phases is determined chromatographically. The error caused by unstationariness of the apparatus was studied. As an example of its use, the vapour-liquid equilibrium data of the N-methylpyrrolidone-ethylene glycol solution at 50 °C are reported. The dependence of excess Gibbs energy on composition was expressed by means of the fourth-order Redlich-Kister and NRTL equations. The system exhibits negative deviation from ideal behaviour. Thermodynamic treatment proves a good consistency of the equilibrium data measured.
Effect of medium on electronic spectra of 4-dimethylamino-ω-nitrostyrenes. Effective Kirkwood-Onsager functions of medium
Authors: Bekárek Vojtěch , Bekárek Vojtěch
Published: June 2010

Wavenumbers of the longest-wave maxima of 1-nitro-2-(4'-dimethylaminophenyl)ethene and 2-nitro-1-(4'-dimethylaminophenyl)propene have been measured in 60 aprotic solvents. The values obtained along with the published data on the effect of medium on electronic spectra of eight other indicators (also measured in gas phase) have been used to suggest effective Kirkwood-Onsager functions for characterization of the overall polarizability of medium, inclusive of the gas phase, in the sense of the method of the product term. Applicability of these functions has been tested for evaluation of the effect of medium on electronic and infrared spectra, reaction rates and equilibria. The effect of medium on the rate of the Menshutkin reactions is interpreted as a consequence of the influence on the fast process (1013 s-1) in the complex formed from the reactants.