bluuebunny/crossref_metadata_2025 huggingface dataset:
Low energy Ar+ ion beam machining of Si thin layer deposited on a Zerodur® substrate for extreme ultraviolet lithography projection optics
Authors: Iwata T. , Fujiwara K. , Pahlovy S. A. , Miyamoto I.
Published: December 2009

For the final correction of the surface figure error of aspherical substrates used in the optics of extreme ultraviolet lithography, ion beam figuring (IBF), which is essentially a machining technique, is regarded as the most promising technique for the job. However, one problem with this technique is that it leaves the surface rougher after the IBF treatment than the surface was before the treatment. Moreover, the machined surface becomes positively charged due to the impact of Ar+ ions that constitute the beam for the IBF processing. Therefore, in this research a Si layer was deposited on a Zerodur® substrate by an ion beam sputtering process, following this process, the deposited substrate was machined by an Ar+ ion beam with energies in the range of 0.3–3keV. The high-spatial-frequency roughnesses (HSFR) of the Zerodur® substrate and of the deposited Si layer were found to be 0.11 and 0.08nm rms, respectively. However, the HSFR of the machined Si layer reaching to a depth of 50nm can be made to go below 0.10nm rms and below 0.15nm rms by employing 0.5 and 1keV Ar+ ion beam energies, respectively. Therefore, the proposed method can be employed by carrying out IBF on the substrates used in extreme ultraviolet lithography projection optics.
Fabrication of nanodot array molds by using an inorganic electron-beam resist and a postexposure bake
Authors: Manabe Tetsuro , Taniguchi Jun , Ishikawa Kiyoshi
Published: December 2009

Nanoimprint lithography (NIL) is regarded as the lithographic technology of the next generation. The photolithography is advancing to perform resolution of 32nm. Although photolithography and high-voltage-acceleration (>50kV) electron-beam-lithography (EBL) techniques are currently used in commercialized lithography, these two methods involve high costs. The authors therefore attempted to fabricate arrays of dots, each with a diameter of 20nm or less, by using low-voltage-acceleration EBL. NIMO-P0701 was used as a positive-type inorganic EB resist in this study and a combination of NIMO-P0701 and low-acceleration-voltage EBL was established. Attempts were then made to use a postexposure bake (PEB) to further reduce the size of the dot array patterns. Finally, the developed dot array mold was transferred by UV-NIL without dry etching. As a result, arrays of dots with a diameter of 20 or 10nm were fabricated by EBL at an acceleration voltage of 4kV and subsequent PEB. The resulting mold was developed with buffered hydrofluoric acid. The developed NIMO-P0701 pattern was used for NIL, and pattern transfer to a UV-curable resin was successfully achieved. In this case, the optimum transfer pressure was 4MPa. Additionally, dot arrays initially produced with diameters of 30 and 18nm were shrunk to sizes of 20 and 10nm, respectively, by means of PEB.
Nanoimprint planarization of high aspect ratio nanostructures using inorganic and organic resist materials
Authors: Chang Allan S. P. , Peroz Christophe , Liang Xiaogan , Dhuey Scott , Harteneck Bruce , Cabrini Stefano
Published: December 2009

Planarization is often crucial to the implementation of three-dimensional devices and systems. By using a pressing process analogous to nanoimprint, the authors show that moderate to high aspect ratio (⩾3) photonic nanostructures in the form of one-dimensional and two-dimensional photonic crystals can be effectively planarized with thermally cured sol-gel or uv-curable nanoimprint resist materials. The planarization results are strongly dependent on parameters such as pressing pressure, hydrophobicity of feature surface, spin conditions for sol-gel, and dispense volume for uv-curable. High degree of planarization and complete filling of open features can be achieved through optimization of imprint parameters. Nanoimprint planarization may thus offer a simple, low cost, fast, and viable alternative planarization methodology.
Fabrication methods for creating flexible polymer substrate sensor tags
Authors: Ho Harvey , Skinner Jack L.
Published: December 2009

The authors describe the design, fabrication, and testing of a passive wireless sensor platform utilizing low-cost commercial surface acoustic wave (SAW) filters and sensors. Polyimide and polyethylene terephthalate sheets are used as substrates to create a flexible sensor tag that can be applied to curved surfaces. A microfabricated antenna is integrated on the substrate in order to create a compact form factor. The sensor tags are fabricated using 315MHz SAW filters and photodiodes and tested with the aid of a fiber-coupled tungsten lamp. Microwave energy transmitted from a network analyzer is used to interrogate the sensor tag. Due to an electrical impedance mismatch at the SAW filter and sensor, energy is reflected at the sensor load and reradiated from the integrated antenna. By selecting sensors that change electrical impedance based on environmental conditions, the sensor state can be inferred through measurement of the reflected energy profile. Testing has shown that a calibrated system utilizing this type of sensor tag can detect distinct light levels wireless and passively. The authors also demonstrate simultaneous operation of two tags with different center passbands that detects light. Ranging tests show that the sensor tags can operate at a distance of at least 3.6m.
SU-8-based immunoisolative microcontainer with nanoslots defined by nanoimprint lithography
Authors: Kwon Joonbum , Trivedi Krutarth , Krishnamurthy Nemani V. , Hu Walter , Lee Jeong-Bong , Gimi Barjor
Published: December 2009

Cells can secrete biotherapeutic molecules that can replace or restore host function. The transplantation of such cells is a promising therapeutic modality for the treatment of several diseases including type 1 diabetes mellitus. These cellular grafts are encapsulated in semipermeable and immunoisolative membranes to protect them from the host immune system, while allowing the transport of nutrients and small molecules that are required for cell survival and function. The authors report on SU-8-based biocompatible immunoisolative cuboid microcontainers for cell transplantation. Each microcontainer comprises a 300×300×250 or a 1100×1100×250μm3 SU-8 hollowed cuboid base that houses the cells and an optically transparent SU-8-based nanoporous lid that closes the device. The hollowed cuboid base was formed by conventional optical lithography to have 8nl (200×200×200μm3) encapsulation volume for cellular payload. The lid comprises a thick SU-8 slab with an array of cylindrical wells, whose bottom surface is sealed with a thin nanoporous SU-8 membrane. The nanoporous membrane was created from a 100nm grating (width and spacing) initial silicon mold subjected to a repeated cycle of oxidation and wet etching to achieve a 20nm wide and 200nm pitch nano silicon grating. Nanoimprinting and oblique-angle metal deposition, followed by inductively coupled plasma etching were utilized to create 15nm wide and 350–450nm deep nanoslots in the thin SU-8 membrane. Isolated mouse islets were encapsulated in the hollowed cuboid base and the nanoporous lid was assembled on top. The penetration of large and small molecules into the microcontainer was observed with fluorescence.
Conductive atomic force microscopy study of self-assembled silicon nanostructures
Authors: Bari M. R. , Blaikie R. J. , Fang F. , Markwitz A.
Published: December 2009

Understanding the electrical transport properties of nanostructures and metal-nanostructure contacts is important before these can be fabricated into electronic devices. Conductive atomic force microscopy investigations of self-assembled silicon nanostructures are reported here, where the nanostructures are fabricated using electron-beam rapid thermal annealing, a self-assembly process that has been shown to produce field-emission devices using CMOS-compatible technology. Unambiguous correlations between current flow and topography are found, and local current-voltage (IV) spectroscopy measurements are used to determine the ideality factors (1.83–3.20) and barrier heights (0.28–0.49eV) for the metal-nanostructure contacts.
Complete reversal imprinting for fabricating microlens arrays with faithful shape replication
Authors: Huang Po-Hsun , Yang Sen-Yeu
Published: December 2009

This article reports a complete reversal imprinting technique for fabrication of microlens array. During this process, by pressing the polymethyl methacrylate substrate against the stainless-steel mold coated with UV-curable resin, the resin microlens array can be transferred from mold to substrate. With this modification of reversal imprinting, the microlens array could be fabricated without difficulty. The uniformity, profiles, and optical properties of the microlenses have been verified. This complete reversal imprinting technique shows its great potential for fabricating microlens arrays with faithful replication.
Two stage ion beam figuring and smoothening method for shape error correction of ULE® substrates of extreme ultraviolet lithography projection optics: Evaluation of high-spatial frequency roughness
Authors: Kamijo Kazuma , Uozumi Ryou , Moriziri Kenta , Pahlovy S. A. , Miyamoto Iwao
Published: December 2009

The ULE® substrates used in projection optics of extreme ultraviolet lithography (EUVL) tools are mechanically prefinished with shape accuracy of several nanometer rms (specification: under 0.15 nm rms) with high-spatial frequency roughness (HSFR) (spatial wavelength: under 1 μm) of 0.06 nm rms. The ion beam figuring is used for the final shape error correction of the substrates at low spatial wavelength of greater than 1 mm using high energy (5–10 keV) Ar+ ion beam with 1 mm beam diameter. However, the surface roughness values of the ULE® substrates when machined by 5 and 10 keV Ar+ ion beams result in 0.15 and 0.17 nm rms, respectively; also it is to be noted that these values are greater than the required 0.15 nm rms specification of HFSR. Therefore, the authors developed a method where low energy (0.3 and 0.5 keV) ion beams are used for smoothening the surface of ULE® substrates, previously treated with high energy (5 and 10 keV) ion beams for figuring. By this two-stage operation of ion beam figuring and followed by smoothening, ULE® substrates with HSFR of 0.1 nm rms were obtained. Therefore, the authors conclude that the method presented here is one of the most effective methods for the figure error correction of ULE® substrate and will be useful in EUVL projection optics.
Focused ion beam-assisted bending of silicon nanowires for complex three dimensional structures
Authors: Jun Kimin , Joo Jaebum , Jacobson Joseph M.
Published: December 2009

Functional three dimensional (3D) nanowire structures are possible candidates for future high density and high performance devices. Unfortunately, few methods are known for manipulating nanowires into arbitrary 3D structures, which can be essential for creating a fully general class of devices. In this article, the authors describe a method to fabricate complex 3D nanowire structures by focused ion beam assisted bending. The authors suggest that the stresses induced by beam irradiation account for the bending. By controlling parameters, it was demonstrated that various bending structures may be constructed either on the fly or programmable.
Fabrication of nanoscale “curtain rods” for DNA curtains using nanoimprint lithography
Authors: Fazio T. A. , Visnapuu M. , Greene E. C. , Wind S. J.
Published: December 2009

The authors have developed a new lithographically based patterning process which significantly increases the throughput of experiments which probe how repair proteins scan DNA molecules for errors. In this process, nanoscale barriers are formed to interrupt the flow of a lipid bilayer in which DNA is tethered to proteins in the bilayer. The barriers trap the DNA, which is then stretched out by hydrodynamic flow, resulting in the formation of “DNA curtains.” Nanoimprint lithography is used to facilitate massively parallel data collection for protein diffusion experiments on DNA.
Submillisecond post-exposure bake of chemically amplified resists by CO2 laser spike annealing
Authors: Sha Jing , Jung Byungki , Thompson Michael O. , Ober Christopher K. , Chandhok Manish , Younkin Todd R.
Published: December 2009

Pattern formation in a chemically amplified photoresist requires a post-exposure bake (PEB) to catalytically deprotect the polymer. Excessive diffusion of the photogenerated acid results in the loss of line edge definition, blurring of latent images, and changes in the line edge roughness. To optimize the process, the authors have explored submillisecond PEB using a CO2 laser-based scanned annealing system [M. Chandhok (private communication)]. Several polymer and photoacid generator resist systems were studied under 800μs laser spike annealing at estimated temperatures between 200 and 400°C. All the resist systems exhibit remarkable stability in this time/temperature regime, with the maximum useful temperature limited by thermal deprotection and/or decomposition of the polymer backbone. At lower temperatures, high resolution patterns with sub-100-nm features are formed, comparable to hotplate reference samples. Resist sensitivity is improved significantly for several resist systems (dose to clear is lowered), while other systems exhibit little change in photosensitivity.
In situ synthesis and direct immobilization of ssDNA on electron beam patterned hydrogen silsesquioxane
Authors: Negrete Omar D. , Onses M. Serdar , Nealey Paul F. , Cerrina Franco
Published: December 2009

In addition to being a high-resolution negative-tone electron beam resist, hydrogen silsesquioxane (HSQ) has chemical properties similar to glass, making it useful for integration with biodevice fabrication. The authors demonstrate the use of electron beam patterned HSQ as a solid support for light-directed in situ ssDNA synthesis and ssDNA immobilization, creating submicron HSQ structures (ranging from 1μmto40nm) that are functionalized with ssDNA. After ssDNA synthesis, the hybridization of Cy-3 labeled complementary strands reveals that the synthesis is indeed localized to the HSQ. They observed relatively low background fluorescence from the supporting silicon substrate or from HSQ where no DNA synthesis was performed. In the course of the experiment they surveyed several materials as support for the HSQ patterning. In addition, the support substrate must be resistant to DNA synthesis. They found that piranha cleaned silicon, glassy carbon, hydrogen plasma treated glassy carbon, and hexamethyldisilazane primed silicon allow little or no synthesis when examined by hybridization with fluorescent labeled complement DNA. This work is relevant to the fabrication of devices that may require submicron patterns of structures functionalized with ssDNA for hybridization assays or DNA self-assembly applications and demonstrates a novel use of a commonly used negative-tone resist.
Sub-15nm nanoimprint molds and pattern transfer
Authors: Morecroft Debbie , Yang Joel K. W. , Schuster S. , Berggren Karl K. , Xia Qiangfei , Wu Wei , Williams R. Stanley
Published: December 2009

This work addresses the challenges in fabricating sub-10nm sized features, dense (sub-15nm half-pitch) arbitrary-pattern nanoimprint molds, as well as pattern transfer of the molds using nanoimprint. The molds were fabricated using an optimized electron-beam lithography process with hydrogen silsesquioxane (HSQ) resist. Two different mold-processing routes were investigated: (1) HSQ patterns on top of a silicon substrate were directly used for nanoimprint and (2) the HSQ patterns on the mold were transferred into the underlying silicon substrate to increase the aspect ratio of the patterns prior to imprint. After the nanoimprint, lift-off was carried out to demonstrate that the pattern could be transferred into functional materials. The difference between the two mold-processing routes is discussed. The results show excellent resolution transfer throughout the process flow to create sub-15nm half-pitch patterns in functional materials.
EUV pattern defect detection sensitivity based on aerial image linewidth measurements
Authors: Goldberg K. A. , Mochi I. , Naulleau P. , Liang T. , Yan P.-Y. , Huh S.
Published: December 2009

As the quality of EUV-wavelength mask inspection microscopes improves over time, the image properties and intensity profiles of reflected light can be evaluated in ever-greater detail. The SEMATECH Berkeley Actinic Inspection Tool (AIT) is one such microscope, featuring mask resolution values that match or exceed those available through lithographic printing in current photoresists. In order to evaluate the defect detection sensitivity of the AIT for dense line patterns on typical masks, the authors study the linewidth roughness (LWR) on two masks, as measured in the EUV images. They report the through-focus and pitch dependence of contrast, image log slope, linewidth, and LWR. The AIT currently reaches LWR 3σ values close to 9nm for 175nm half-pitch lines. This value is below 10% linewidth for nearly all lines routinely measured in the AIT. Evidence suggests that this lower level may arise from the mask’s inherent pattern roughness. While the sensitivity limit of the AIT has not yet been established, it is clear that the AIT has the required sensitivity to detect defects that cause 10% linewidth changes in line sizes of 125nm and larger.
Process and properties of the carbon nanotube assisted LiCoO2 thin-film battery electrode by pulsed laser deposition
Authors: Lo An-Ya , Sun Chuan-Shu , Tseng Wen-Shou , Kuo Cheng-Tzu
Published: December 2009

In this study, a pulsed laser deposition process was developed to deposit a carbon nanotube (CNT) assisted LiCoO2 electrode to improve its power density. The electrodes were deposited on Pt-coated Si substrates with Ar and O2 as sputtering gases and LiCoO2+C as the target. The results indicate that the working pressure is the most important parameter to control the composition of the electrode. Therefore, electrodes with a three-layer structure (i.e., LiCoO2-rich/CNT-rich/LiCoO2-rich) were fabricated by a three-step deposition process by varying the pressures from 13 to 1.3×104 Pa and then 13 Pa again, and it was found that the charge/discharge capacity became approximately 1.5 times greater than that in the corresponding electrode without a CNT-rich layer. The results also indicate that a higher substrate temperature is favorable for improving the crystallinity of the electrode to approach LiCoO2 crystals.
Nanogratings containing sub-10-nm wide trenches by dimension reduction from sloped polymer profile
Authors: Trivedi Krutarth , Hu Walter
Published: December 2009

Large area nanograting patterns are useful in many applications but difficult to fabricate. The authors demonstrate a low temperature dimension reduction method, as a cost-effective alternative to high resolution lithography, to define nanogratings as narrow as 8–10nm. In this process, the slope of prepatterned polymer gratings, with pitch of 200nm or larger and width of 100nm or larger, is contrillably changed from the original straight to curved or sloped. Then, shadow metal evaporation is used to coat the sloped polymer profile to define a much narrower opening. This opening is then transferred to underlying material by plasma etching to form sub-10-nm trenches. The width of trenches can be well controlled by both slope of the profile and angle of metal evaporation. Low processing temperature (as low as 55–85°C—depending on polymer) allows this method to be used with a wide variety of materials.
Epidemic Dynamics at the Human-Animal Interface
Authors: Lloyd-Smith James O. , George Dylan , Pepin Kim M. , Pitzer Virginia E. , Pulliam Juliet R. C. , Dobson Andrew P. , Hudson Peter J. , Grenfell Bryan T.
Published: December 2009

Zeroing in on Zoonoses

Influenza, plague, and Lyme disease are classic examples of zoonoses—diseases that circulate in livestock and wildlife, as well as in humans. When a pathogen transfers among multiple hosts, the dynamics of circulation, transmission, and outbreak are complex.

Lloyd-Smith
et al.

(p.
1362
) review the use of analytical mathematical tools, particularly modeling, in the development of control policies and research agendas. Significant gaps are highlighted in analytical efforts during spillover transmission from animals into humans. Moreover, the tendency has been to focus on pathogens with simpler life cycles and of immediate global urgency, such as influenza, whereas insect-transmitted pathogens with complex, multihost life cycles are less well understood.
Tracking the Variable North Atlantic Sink for Atmospheric CO
2
Authors: Watson Andrew J. , Schuster Ute , Bakker Dorothee C. E. , Bates Nicholas R. , Corbière Antoine , González-Dávila Melchor , Friedrich Tobias , Hauck Judith , Heinze Christoph , Johannessen Truls , Körtzinger Arne , Metzl Nicolas , Olafsson Jon , Olsen Are , Oschlies Andreas , Padin X. Antonio , Pfeil Benjamin , Santana-Casiano J. Magdalena , Steinhoff Tobias , Telszewski Maciej , Rios Aida F. , Wallace Douglas W. R. , Wanninkhof Rik
Published: December 2009

A Happy Marriage

The fluxes of CO
2
between the atmosphere and ocean are large and variable, and understanding why the concentration of atmospheric CO
2
changes as it does, depends on accurately determining the details of those fluxes. One of the major obstacles in the way of quantifying this exchange is that there are too few measurements available, both temporally and geographically.

Watson
et al.

(p.
1391
) report results from a happy marriage of science and commerce—data collected by instruments fitted onto commercial ships plying the waters of the North Atlantic Ocean—that has generated the largest and most comprehensive set of measurements of ocean pCO
2
ever collected. These data allow the oceanic CO
2
sink to be monitored with unprecedented accuracy and will help researchers precisely map regional interannual air-sea fluxes.
Mantle Shear-Wave Velocity Structure Beneath the Hawaiian Hot Spot
Authors: Wolfe Cecily J. , Solomon Sean C. , Laske Gabi , Collins John A. , Detrick Robert S. , Orcutt John A. , Bercovici David , Hauri Erik H.
Published: December 2009

Earth's Plume Plumbing

Volcanic hot spots, such as the one that continues to build the Hawaiian Islands, are thought to form by one of two mechanisms: Either mantle plumes bring hot, buoyant material to the surface from deep within the Earth's interior, or extensive processing of the upper mantle by plate tectonics causes localized volcanism in stressed or heterogeneous crust.

Wolfe
et al.

(p.
1388
; see the cover; see the news story by

Kerr

) used an extensive array of ocean-bottom and land-based seismometers to reveal the structure of the mantle beneath Hawaii. These high-resolution images reveal a high-temperature plume originating from the lower mantle.
Targeted 3′ Processing of Antisense Transcripts Triggers
Arabidopsis FLC
Chromatin Silencing
Authors: Liu Fuquan , Marquardt Sebastian , Lister Clare , Swiezewski Szymon , Dean Caroline
Published: December 2009

Flowery Regulator

Control of gene transcription is multilayered, depending on transcription factors, epigenetic mechanisms, and interactions with small RNA molecules.

Liu
et al.

(p.
94
, published online 3 December) have now found that for the
FLOWERING LOCUS C
(
FLC
) gene of the plant
Arabidopsis
, a backwards transcript of the gene conspires with 3′ RNA-processing tools and histone demethylation to regulate the transcription of the protein-coding gene. The 3′-processing events require the antisense, not the sense, RNA transcript. It is then the sense transcript that, in the end, regulates onset of flowering.
Harnessing Carbon Payments to Protect Biodiversity
Authors: Venter Oscar , Laurance William F. , Iwamura Takuya , Wilson Kerrie A. , Fuller Richard A. , Possingham Hugh P.
Published: December 2009

A model shows that REDD (reducing emissions from deforestation and degradation) can be extended to biodiversity conservation.
On the Elusive Twelfth Vibrational State of Beryllium Dimer
Authors: Patkowski Konrad , Špirko Vladimír , Szalewicz Krzysztof
Published: December 2009

One More Vibration

The beryllium dimer has puzzled chemists for the better part of a century because its bond, though weak by molecular standards, is much stronger than standard bonding frameworks would predict. Recent spectroscopic measurements have characterized the molecule in great detail, but leave open the question of whether a high-energy vibrational state might lie just below the threshold for scission of the bond.

Patkowski
et al.

(p.
1382
) have now derived a potential energy function, based on high-level theoretical calculations and, by slightly modifying it through fitting to the experimental data, obtained strong evidence for the presence of the upper vibrational state. Taken together with the measured spectra, these results offer a well-grounded basis for understanding the unusual molecule.
Deletion of Atoh1 Disrupts Sonic Hedgehog Signaling in the Developing Cerebellum and Prevents Medulloblastoma
Authors: Flora Adriano , Klisch Tiemo J. , Schuster Gabriele , Zoghbi Huda Y.
Published: December 2009

Medulloblastoma and Atoh1

The Atoh1 transcription factor is needed for normal brain development and is also implicated in some cancers of the brain. In order to study the latter function and avoid the perinatal lethality that follows early disruption of the
Atoh1
gene,

Flora
et al.

(p.
1424
) knocked out the
Atoh1
gene in mice after birth. A few days after the genetic knockout, cells at the surface of the cerebellum had begun to differentiate earlier than normal. Overexpression of
Atoh1
, on the other hand, led to excessive cell growth and even preneoplastic lesions at the surface of the cerebellum.
Atoh1
was found to regulate expression of the
Gli2
gene, and thereby Sonic Hedgehog signaling, which normally keeps cerebellar precursor cells undifferentiated.
Quantum Nonlocality: How Does Nature Do It?
Authors: Gisin Nicolas
Published: December 2009

Measurements of correlations between spatially separated systems provide insights into the conceptual foundations of quantum physics.
The End of Deforestation in the Brazilian Amazon
Authors: Nepstad Daniel , Soares-Filho Britaldo S. , Merry Frank , Lima André , Moutinho Paulo , Carter John , Bowman Maria , Cattaneo Andrea , Rodrigues Hermann , Schwartzman Stephan , McGrath David G. , Stickler Claudia M. , Lubowski Ruben , Piris-Cabezas Pedro , Rivero Sergio , Alencar Ane , Almeida Oriana , Stella Osvaldo
Published: December 2009

Government commitments and market transitions lay the foundation for an effort to save the forest and reduce carbon emission.
Biodiversity Under Global Change
Authors: Collins Scott L.
Published: December 2009

A long-term experiment into plant community responses to elevated carbon dioxide and nitrogen yields surprising results.
Researchers Writing for the Public
Science for All
The Popularization of Science in Early Twentieth-Century Britain

by Peter J. Bowler

University of Chicago Press, Chicago, 2009. 351 pp. $45, £31. ISBN 9780226068633.
Authors: Baldwin Melinda
Published: December 2009

Bowler argues that despite the professionalization of their disciplines, through the middle of the 20th century British scientists remained very active in writing about their work for general readers.
Nascent Proteins Caught in the Act
Authors: Kampmann Martin , Blobel Günter
Published: December 2009

Cryo–electron microscopy structures visualize two types of nascent polypeptide chains that affect either protein translocation across membranes or regulation of bacterial gene expression.
Nailing Down Nickel for Electrocatalysis
Authors: Hambourger Michael , Moore Thomas A.
Published: December 2009

A nickel compound bound to carbon nanotubes catalyzes a key reaction for hydrogen fuel cells and electrolyzers, the interconversion of protons and hydrogen in water.
Stolen E-mails Turn Up Heat on Climate Change Rhetoric
Authors: Kintisch Eli
Published: December 2009

The theft and unauthorized release last month of 1000 private e-mail messages from the servers of the Climatic Research Unit at the University of East Anglia in the United Kingdom has raised thorny questions about the proper behavior of researchers who feel under siege for their science. How willing should they be to share their raw data with their staunchest critics?
Acting Like a Prion Isn't Always Bad
Authors: Miller Greg
Published: December 2009

If misfolded proteins are so dangerous, why hasn't evolution selected against them? One possibility is that it hasn't had to: Many of the diseases caused by protein misfolding strike late in life, after the reproductive years are over. It's also possible that this type of protein folding isn't always bad.
Randomized, Double-Blind Study of the Safety, Tolerability, and Efficacy of Tafenoquine versus Mefloquine for Malaria Prophylaxis in Nonimmune Subjects
Authors: Nasveld Peter E. , Edstein Michael D. , Reid Mark , Brennan Leonard , Harris Ivor E. , Kitchener Scott J. , Leggat Peter A. , Pickford Philip , Kerr Caron , Ohrt Colin , Prescott William
Published: December 2009

This study represents the first phase III trial of the safety, tolerability, and effectiveness of tafenoquine for malaria prophylaxis. In a randomized (3:1), double-blinded study, Australian soldiers received weekly malaria prophylaxis with 200 mg tafenoquine (492 subjects) or 250 mg mefloquine (162 subjects) for 6 months on a peacekeeping deployment to East Timor. After returning to Australia, tafenoquine-receiving subjects received a placebo and mefloquine-receiving subjects received 30 mg primaquine daily for 14 days. There were no clinically significant differences between hematological and biochemical parameters of the treatment groups. Treatment-related adverse events for the two groups were similar (tafenoquine, 13.4%; mefloquine, 11.7%). Three subjects on tafenoquine (0.6%) and none on mefloquine discontinued prophylaxis because of possible drug-related adverse events. No diagnoses of malaria occurred for either group during deployment, but 4 cases (0.9%) and 1 case (0.7%) of
Plasmodium vivax
infection occurred among the tafenoquine and mefloquine groups, respectively, up to 20 weeks after discontinuation of medication. In a subset of subjects recruited for detailed safety assessments, treatment-related mild vortex keratopathy was detected in 93% (69 of 74) of tafenoquine subjects but none of the 21 mefloquine subjects. The vortex keratopathy was not associated with any effect on visual acuity and was fully resolved in all subjects by 1 year. Tafenoquine appears to be safe and well tolerated as malaria prophylaxis. Although the volunteers' precise exposure to malaria could not be proven in this study, tafenoquine appears to be a highly efficacious drug for malaria prophylaxis.
Evaluation of Flagella and Flagellin of
Pseudomonas aeruginosa
as Vaccines
Authors: Campodónico Victoria L. , Llosa Nicolás J. , Grout Martha , Döring Gerd , Maira-Litrán Tomás , Pier Gerald B.
Published: December 2009

Pseudomonas aeruginosa
is a serious pathogen in hospitalized, immunocompromised, and cystic fibrosis (CF) patients.
P. aeruginosa
is motile via a single polar flagellum made of polymerized flagellin proteins differentiated into two major serotypes: a and b. Antibodies to flagella delay onset of infection in CF patients, but whether immunity to polymeric flagella and that to monomeric flagellin are comparable has not been addressed, nor has the question of whether such antibodies might negatively impact Toll-like receptor 5 (TLR5) activation, an important component of innate immunity to
P. aeruginosa
. We compared immunization with flagella and that with flagellin for
in vitro
effects on motility, opsonic killing, and protective efficacy using a mouse pneumonia model. Antibodies to flagella were superior to antibodies to flagellin at inhibiting motility, promoting opsonic killing, and mediating protection against
P. aeruginosa
pneumonia in mice. Protection against the flagellar type strains PAK and PA01 was maximal, but it was only marginal against motile clinical isolates from flagellum-immunized CF patients who nonetheless became colonized with
P. aeruginosa
. Purified flagellin was a more potent activator of TLR5 than were flagella and also elicited higher TLR5-neutralizing antibodies than did immunization with flagella. Antibody to type a but not type b flagella or flagellin inhibited TLR5 activation by whole bacterial cells. Overall, intact flagella appear to be superior for generating immunity to
P. aeruginosa
, and flagellin monomers might induce antibodies capable of neutralizing innate immunity due to TLR5 activation, but solid immunity to
P. aeruginosa
based on flagellar antigens may require additional components beyond type a and type b proteins from prototype strains.
Effects of the Srl5 allele for resistance on development of the stem rust fungus and cellular responses in wheat
Authors: Gousseau H. D. M. , Deverall B. J.
Published: December 2009

The development of avirulent and virulent strains of stem rust (Puccinia graminis Pers. f.sp. tritici Eriks. & Henn.) in a susceptible wheat line and two cultivars bearing the Sr15 allele for resistance was studied, mainly by fluorescence microscopy. Formation of appressoria, substomatal vesicles, infection hyphae, and the first haustorium was unaffected by resistance. The first effect of Sr15 expression was a slower rate of haustorial mother cell formation and was first seen 48 h after inoculation. Effects on hyphal branching and colony radii followed. Necrosis of host cells was first seen at 42 h, but inspection of individual infection sites showed that necrosis did not coincide with effects on haustorial mother cells. It is possible that deterioration of host cells leading to visible host cell necrosis may be related to effects on rust development. Sr15 expression gave a mesothetic reaction, first seen microscopically 60 h after inoculation. Differences between individual infection sites in this reaction may be related to the timing of the onset of necrosis.
Vascular cambium and wood development in Carboniferous plants. III. Arthropitys (Equisetales; Calamitaceae)
Authors: Cichan Michael A.
Published: December 2009

Vascular cambium activity was examined in Arthropitys communis (Binney) Hirmer et Knoell, and A. deltoides Cichan et Taylor, anatomically preserved calamite stems from the Pennsylvanian of Kentucky. Developmental characteristics of the meristem were inferred from changes in the size and number of tracheids and ray cells determined from serial tangential sections of the secondary xylem. In A. communis, circumferential enlargement of the cambium seems to have been accommodated primarily by the enlargement of fusiform initials. Qualitative and quantitative evidence is also presented indicating that “marginal” interfascicular ray initials were converted to fusiform initials during the early stages of cambial activity. In A. deltoides, circumferential enlargement of the meristem was accommodated by the enlargement of fusiform initials and by an increase in size and number of interfascicular ray initials. Multiplicative division of the fascicular ray initials appears to have been an important feature of cambial activity in both species. There is no qualitative or quantitative evidence that the number of fusiform initials in either species was augmented by anticlinal division as in extant seed plants.
Effects of simulated acid fog on leaf acidification and injury development of pinto beans
Authors: Bytnerowicz A. , Temple P. J. , Taylor O. C.
Published: December 2009

Pinto beans (Phaseolus vulgaris L. cv. UI 111) were exposed for 8 h to simulated fog solutions made up of 2:1 nitric acid: sulfuric acid plus background ions, acidified to pH 3.2, 2.8, 2.4, and 2.0. Rate of fog deposition was ca. 1 mm h−1. Examination of visible foliar injury development, scanning electron microscopy (SEM) examination, and measurement of leaf extract pH were performed every 2 h. Both visual and SEM observations during exposure showed no change in leaf surface characteristics for plants exposed to pH 3.2 and 2.8 fog solutions but 1 week after pH 2.8 exposures, injury was seen on primary leaves and young trifoliate leaves. The first indications of injury at pH 2.4 were seen under SEM after 8 h of exposure. Foliar injury was apparent after only 2 h of exposure at pH 2.0 and severe acid necrosis developed after 24 h. Changes in acidity of leaf extracts were closely correlated with subsequent injury development. No changes were observed in extracts of plants exposed to pH 3.2 simulated fog compared with controls. After 8 h of exposure, leaf extracts of plants exposed to pH 2.8 fog had dropped 0.05 pH units. Plants exposed to pH 2.4 and pH 2.0 for 8 h had leaf extracts that were 0.12 and 0.18 pH units lower, respectively. Comparison of the three measured parameters of acid fog effects (visible injury development, SEM examination of leaf surfaces, and determination of leaf extract pH) showed extract pH to be a simple, quantifiable, and sensitive indicator of the negative effects of acid precipitation on plants.
Late embryogenesis and morphology of mature embryos in three species of Dipterocarpaceae
Authors: Swarupanandan K.
Published: December 2009

Stereoscopic dissection of seeds in different stages of development allows morphological study of late embryogenesis in large-seeded spermatophytes. Using this method, late embryogenesis is studied in three species of Dipterocarpaceae, viz., Hopea ponga (Dennst.) Mabb., Vateria indica Linn., and Vatica chinensis Linn. Configuration of the mature embryo in the seed is largely a result of spatiotemporal growth adjustments in all three species. Thus, the kind of folding of the cotyledons and the position of the embryonic hypocotyl (radicle) in the mature embryo are largely determined by the position of the embryo inside the ovule (seed) cavity early in development. Late embryogenic studies in other species of Dipterocarpaceae and other angiosperms are desirable. Such studies would help in understanding causal morphology and structural homology of embryos.
Characterization of the structural inclusions in the latex of banana (Musa sp.)
Authors: Kallarackal J. , Garlick P. R. , Milburn J. A.
Published: December 2009

Because of the importance of latex in indicating the water relations of the banana plant, the structural inclusions in the latex have been examined using microscopic, cytochemical, and analytical methods. Banana latex is a colloidal suspension of diverse organelles. The major organelles have been identified as lipid globules, lutoids, and cytoplasmic fragments. A few raphides and threadlike inclusions were also found. The lipid globules were comparatively large and most of them had an electron-opaque crust around them. The lutoids occurred in two morphologically different forms: globular vesicles and crystalloid vesicles. They were osmotically active and a maximum number of them were in the expanded state when the solute potential of the suspending medium was approximately −0.5 MPa. They had a unit membrane around them and various membraneous structures inside. The crystalloid lutoids had long hexagonal crystals inside them. Some of the globular lutoids had nuclear materials in them. The cytoplasmic fragments occurred as globular structures with a plasma membrane around them. They had granular contents and showed the derivation of vesicles from the plasma membrane. From their staining and ultrastructural characteristics, it is believed that the lutoids have vacuolysosomal activity.
The flavonoids of Arnica frigida and A. louiseana (Asteraceae)
Authors: Downie Stephen R. , Denford Keith E.
Published: December 2009

Forty-six populations within the Arnica frigida Meyer ex Iljin – louiseana Farr complex were examined for flavonoid content. Seven glycosides were isolated and six identified. Members of this complex were found to produce primarily quercetin and kaempferol 3-O-glycosides. Flavonoid profiles obtained from A. frigida ssp. frigida were the most diverse and in some cases the most depauperate. Within this taxon, flavonoid diversity appears to have accompanied high morphological variability. The occurrence of flavonoid-depauperate plants in unglaciated Alaska suggests that flavonoids are of value in identifying refugia. Flavonoid profile similarities between A. frigida ssp. frigida and A. frigida ssp. griscomii corroborate morphological evidence as to the close affinity between these two taxa.
The identification and characteristics of a mutation in Bremia lactucae resulting in large lipid inclusions in the conidiosporangia
Authors: Norwood Judith M. , Crute I. R. , Clay C. M. , Whenham R. J.
Published: December 2009

During an investigation involving the production of sexual recombinants of Bremia lactucae, isolates were identified which contained atypical large spherical inclusions in their conidiosporangia. These were visible under the light microscope. Since these inclusions stained red with Sudan III and disappeared as the conidia germinated, they were assumed to be reserves of lipid. Storage lipid in normal spores is distributed as numerous small droplets at the perimeter of the spore near the plasmalemma, whereas in the mutant, lipid occurred as large droplets within the spore. There was no significant difference between normal and mutant spores in their total lipid content or their hydrocarbon or fatty acid profiles. Mutant spores germinated as readily as normal spores and there was no apparent effect of the mutation on pathogenic competence. The character appeared to be inherited as a single recessive gene. The use of this marker for investigations on the relative fitness of isolates under different environmental conditions is discussed.
THE LIPOTROPIC ACTIVITY OF PROTEIN
Authors: Lucas C. C. , Ridout Jessie H.
Published: December 2009

A distinct lipotropic effect of casein has been observed in rats under conditions that appear to preclude any explanation involving the methionine or choline content of the ration. Diets low in protein produce a type of fatty liver that is not prevented by choline and is histologically different from that of choline deficiency. Choline appears less effective in such diets than in ones more adequate in protein. Presumably choline has only a limited effect on abnormal fat in periportal regions because the biochemical basis of this lesion seems to involve faulty formation of lipoprotein due to shortage of essential amino acids.
THE PYRUVIC PHOSPHOFERASE OF ERYTHROCYTES: I. PROPERTIES OF THE ENZYME AND ITS ACTIVITY IN ERYTHROCYTES OF VARIOUS SPECIES
Authors: Solvonuk P. F. , Collier H. R.
Published: December 2009

Mammalian erythrocytes contain a pyruvic phosphoferase (PPFase) which is activated by K+and Mg++and inhibited by Na+and Ca++. The K+can be replaced by Rb+or NH4+, and the Mg++can be partially replaced by Mn++or Co++as activators of the enzyme. The PPFase apparently requires free thiol groups for its activity, as it is completely inhibited by 10−4 M p-chloromercuribenzoate and this inhibition is partially reversed by glutathione. The mean PPFase of the erythrocytes of six mammalian species was determined and found to be in the following order of decreasing activity: man, rat, dog, rabbit, cat, ox. The erythrocytes of chicks and of newborn rats showed a very high PPFase activity.
ON RAT SERUM AMYLASE: II. THE INFLUENCE OF DIET ON LEVELS OF THE ENZYME
Authors: Wiberg G. Stuart , Tuba Jules
Published: December 2009

The relationship between food consumption and rat serum amylase previously reported has been further investigated, this time with the use of synthetic diets. With high carbohydrate diets neither sucrose nor corn starch exerted any significant influence on the rat serum amylase level. A high concentration of protein in the diet produced a highly significant decrease in the activity of the enzyme. On the other hand, a high fat diet resulted in a highly significant elevation of serum amylase. The effect of fat was proportional to concentration up to a limiting value. In diets which lacked carbohydrate or when the carbohydrate was completely or largely indigestible, levels of the enzyme were depressed significantly below normal. With protein-free diets, a regimen consisting largely of fat and carbohydrate, enzyme levels were depressed significantly when sucrose was used, whereas amylase values were normal when starch was used as the carbohydrate.
LECITHINASES IN NORMAL AND IN PATHOLOGICAL CEREBROSPINAL FLUIDS (CSF). I
Authors: Kovacs E.
Published: December 2009

More than 480 CSF's were examined for lecithinase activity. No lecithin splitting was evident in definitely normal CSF. In 60% of the neurologically normal group moderate phospholipase level was demonstrated. Activity was found in a slightly higher number (64%) of the CSF's of meningitis patients. Of the poliomyelitis group 74% exhibited activity, with more uniformity in, and with higher, values than the first two groups. This finding is correlated with the pathological changes in the peripheral nervous system. The highest enzyme level was found in the syphilitic group, 80% of which showed positive assays. The CSF's of miscellaneous neurological and psychotic conditions occasionally exhibited intense lecithinase activity.
AN INVESTIGATION OF THE COAGULATION DEFECT BROUGHT ABOUT IN RABBITS AND DOGS BY THE INTRAVENOUS INJECTION OF PAPAIN
Authors: Monkhouse Frank C.
Published: December 2009

The intravenous injection of papain causes the blood of dogs and rabbits to become incoagulable. In rabbits the incoagulability persists for many hours. In some animals there remained a mild disturbance in the coagulation system up to two weeks after the injection. The release of heparin can account for part of the effect, but there is evidence of some other contributing factor. Results indicate that the added factor affects the thrombin–fibrinogen reaction. Calcium chloride in excess of that needed for normal coagulation will greatly inhibit the antithrombic effect of commercial beef heparin, and to a lesser extent, the antithrombic effect of an injection of papain.
EMBRYONIC AND POSTEMBRYONIC CHANGES IN THE LIPIDS OF ASCARIS LUMBRICOIDES EGGS
Authors: Fairbairn Donald
Published: December 2009

Unembryonated ascaris eggs contained amounts of saponifiable and unsaponifiable lipids estimated to exceed 50% of the protoplasmic solids. The saponifiables (75–80% of the total lipids) consisted of triglycerides and much smaller quantities of phospholipids. Volatile acids comprised a significant part of the total triglyceride fatty acids. The unsaponifiables (> 20% of the total lipids) contained ascaryl alcohol as the major component. Unesterified sterols were also present. During embryonation and postembryonic survival of the eggs, the saponifiables decreased to 25% of the initial amount present, whereas unsaponifiables remained constant. Death of the embryos coincided with failure to utilize the remaining saponifiables.