bluuebunny/crossref_metadata_2025 huggingface dataset:
The thermal analysis of paraffin wax in a box-type solar cooker
Authors: Yuksel Numan , Arabacıgıl Bihter , Avcı Atakan
Published: November 2012

In this study, the potential use and effectiveness of paraffin wax in solar cooker during the daylight and/or late evening hours is experimentally investigated. For these experiments, a box-type solar cooker was constructed by filling paraffin wax with metal shavings. The side- and sub-surface temperatures of the paraffin wax in the cooker are continuously measured during June and July 2011. The effect of the reflector angle on the thermal efficiency of the cooker is tested with different isolation conditions on different days. In conclusion, the designed cooker can be effectively used at an angle of 30°. The thermal efficiency is increased to around 18.35% with the reflector. The maximum temperature of the paraffin achieved during the experiments is in the range of 75.1 °C to 80.5 °C. The reflected radiation makes a maximum contribution of 13.29% to the temperature of the paraffin wax. In addition, the heating time is decreased to approximately 1 h. So, the paraffin wax could be used as a phase change material integrated with the solar system. The rectangular solar cooker filled with the paraffin wax has a high thermal performance, which is indicated by high temperatures and decreased cooking times, for the given design conditions.
The mechanisms of random trap fluctuation in metal oxide semiconductor field effect transistors
Authors: Hsieh E. R. , Chung Steve S.
Published: November 2012

An effect, called random trap fluctuation (RTF), is proposed to study the threshold voltage (Vth) fluctuation of metal oxide semiconductor field effect transistors (MOSFETs) under Fowler-Nordeim (FN) or hot carrier (HC) stress condition. Experiments have been demonstrated on n-channel MOSFETs, and it was found that not only the random dopant fluctuation (RDF) but also the stress-induced traps vary the Vth fluctuation. More importantly, the stress-induced trap barrier determines the Vth fluctuation. For devices after FN stress, Vth fluctuation is enhanced since the trap barrier regulates the transporting carriers. For devices after HC stress, Vth fluctuation is supressed since the carriers are backscattered into the channel by the trap barrier and fewer carriers with higher energy pass through the barrier. These results provide us a clear understanding on another source of Vth fluctuations in addition to the RDF as devices are further scaled.
Femtosecond laser direct hard mask writing for selective facile micron-scale inverted-pyramid patterning of silicon
Authors: Kumar K. , Lee K. K. C. , Herman P. R. , Nogami J. , Kherani N. P.
Published: November 2012

We report on the fabrication of high-fidelity inverted-pyramids in crystalline silicon (c-Si) at the 1 μm scale through the selective removal of a silicon nitride (SiNx) hard-mask with a 522 nm femtosecond (fs) laser and subsequent alkaline potassium hydroxide (KOH) etching. Through a series of systematic experiments on a range of hard-mask thicknesses, the use of 20 nm thick SiNx film yielded a 0.6 μm diameter laser-ejected aperture in the hard-mask at a single pulse fluence of 0.45 J cm−2, resulting in 1 μm wide inverted-pyramid structure in c-Si after KOH etching. Anisotropic KOH etching of the partially amorphized c-Si underlying the fs-laser patterned hard mask was found to render clean (111) planes of c-Si. An array of inverted-pyramids on c-Si surfaces as large as 4 cm2 was produced with a defect density of less than 1 in 104. This facile, non-contact, and cleanroom-independent technique serves a variety of applications including anti-reflective texturing of thin c-Si for photovoltaics, wafer marking, labeling, and fabrication of microfluidic and optical devices or laboratories on silicon wafers.
Ohmic contact on n-type Ge using Yb-germanide
Authors: Zheng Zhi-Wei , Ku Teng-Chieh , Liu Ming , Chin Albert
Published: November 2012

Poor ohmic contact by Fermi-level pinning to valence band (EV) edge is one of the major challenges for germanium (Ge) n-type metal–oxide–semiconductor field-effect transistor (nMOSFET). Using low work-function rare-earth ytterbium (Yb), good ohmic contact on n-type Ge with alleviated Fermi-level pinning was demonstrated. Such ohmic behavior depends strongly on the germanide formation condition, where much degraded ohmic contact at 600 °C rapid thermal annealing is due to the lower Yb/Ge composition found by energy-dispersive x-ray spectroscopy. The ohmic behavior of Yb-germanide/n-type-Ge has high potential for future high-performance Ge nMOSFET application.
Mapping of native inorganic elements and injected nanoparticles in a biological organ with laser-induced plasma
Authors: Motto-Ros V. , Sancey L. , Ma Q. L. , Lux F. , Bai X. S. , Wang X. C. , Yu Jin , Panczer G. , Tillement O.
Published: November 2012

Emission spectroscopy of laser-induced plasma from a thin section of mouse kidney successfully detected inorganic elements, Na, Ca, Cu, and Gd, naturally contained in the organ or artificially injected in the form of Gd-based nanoparticle. A two-dimensional scan of the sample allowed the laser beam to explore its surface with a resolution of 100 μm, resulting in a quantitative elemental mapping of the organ with sub-mM sensitivity. The compatibility of the setup with standard optical microscopy emphasizes the potential to provide multiple images of a same biological tissue with different types of response which can be elemental, molecular, or cellular.
Spin waves and small intrinsic damping in an in-plane magnetized FePt film
Authors: Chen Zhifeng , Yi Ming , Chen Ming , Li Shufa , Zhou Shiming , Lai Tianshu
Published: November 2012

Laser-induced spin-wave dynamics in an in-plane magnetized FePt film is studied using all-optical pump-probe magneto-optical Kerr spectroscopy under different external fields and pump fluences. Uniform precession spin wave is observed. Nonlinear external field dependence of its frequency is found and well explained by the macrospin model of uniform precession. The effective damping shows a significant external-field dependence. Calculation taking account for magnetic inhomogeneity fits the external-field dependence well, revealing main magnetic inhomogeneity origin of the extrinsic damping. An intrinsic Gilbert damping parameter of <0.028 is inferred and shows potential applications of this film in magnonics.
High reflectance membrane-based distributed Bragg reflectors for GaN photonics
Authors: Chen Danti , Han Jung
Published: November 2012

Preparation of highly reflective distributed Bragg reflectors (DBRs) from III-nitrides is an important building block for cavity photonics. In this work, we report the fabrication of a membrane-based GaN/air-gap DBR for blue/green light emitting devices. The formation of membrane DBRs relies on a recently discovered electrochemical procedure in which selective etch is achieved by adjusting the conductivity rather than chemical composition, thus relieving greatly the burden in creating epitaxial DBRs. Micro-reflectance measurement shows over 98% peak reflectance and a wide stopband with only four pairs of GaN/air-gap layers. Micro-photoluminescence spectra of InGaN multiple quantum wells (MQWs) on DBRs show reduced linewidth and improved emission efficiency. After capping the MQWs on DBRs with silver, a significant linewidth narrowing indicates the modification of spontaneous emission due to the presence of a planar microcavity.
Tandem organic photodetectors with tunable, broadband response
Authors: Matthew Menke S. , Pandey Richa , Holmes Russell J.
Published: November 2012

Broadband photodetection is achieved by integrating three electron donor materials with complementary absorption into an organic photodetector (OPD). While a single donor-acceptor heterojunction can show broadband response, the spectral tunability is intrinsically limited to the absorption profiles of the active materials. Here, we demonstrate broadband OPDs consisting of multiple bulk heterojunctions arranged in tandem. These OPDs show high responsivity under moderate reverse bias from the ultraviolet to the near-infrared. By combining materials with complementary absorption in a tandem OPD, we demonstrate that the response from each band can be separately tuned with manipulation of the heterojunction thicknesses or composition.
Tunable wetting behavior of nanostructured poly(dimethylsiloxane) by plasma combination treatments
Authors: Peter Nicolas J. , Zhang Xiao-Sheng , Chu Shi-Gan , Zhu Fu-Yun , Seidel Helmut , Zhang Hai-Xia
Published: November 2012

This letter reports on the tunable wetting behavior of poly(dimethylsiloxane) (PDMS) via the combination of nanostructuring and plasma treatment. The PDMS is first micro/nanostructured by an integrated casting process. Subsequently, an inductively coupled plasma is used to modify the siloxanes' surface chemistry. Sulfur hexafluoride, fluoroform, as well as octafluorocyclobutane plasma were applied to treat PDMS samples successively. By optimizing the treatment parameters, tunable wettability of the siloxane was observed, i.e., superhydrophilicity and superhydrophobicity. The stability of its wetting behavior has been demonstrated after 24 h. This stable and tunable wettability extends the applications of PDMS in microfluidic systems.
Reactive oxygen species controllable non-thermal helium plasmas for evaluation of plasmid DNA strand breaks
Authors: Young Kim Jae , Lee Dong-Hoon , Ballato John , Cao Weiguo , Kim Sung-O
Published: November 2012

Non-thermal, oxygen-rich helium plasmas were investigated to achieve an enhanced reactive oxygen species concentration at low voltage driving conditions. A non-thermal plasma device was fabricated based on a theta-shaped tube, and its potential was investigated for use in topological alteration of plasmid DNA. The optical emission spectra of the plasma showed that the oxygen flow affected the plasma properties, even though an oxygen plasma was not produced. The plasmid DNA strand breaks became more significant with the addition of oxygen flow to the helium in a single hollow, theta-shaped tube with other experimental conditions being unchanged.
In-plane electronic confinement in superconducting LaAlO3/SrTiO3 nanostructures
Authors: Stornaiuolo D. , Gariglio S. , Couto N. J. G. , Fête A. , Caviglia A. D. , Seyfarth G. , Jaccard D. , Morpurgo A. F. , Triscone J.-M.
Published: November 2012

We describe the transport properties of mesoscopic devices based on the two dimensional electron gas (2DEG) present at the LaAlO3/SrTiO3 interface. Bridges with lateral dimensions down to 500 nm were realized using electron beam lithography. Their detailed characterization shows that processing and confinement do not alter the transport parameters of the 2DEG. The devices exhibit superconducting behavior tunable by electric field effect. In the normal state, we measured universal conductance fluctuations, signature of phase-coherent transport in small structures. The achievement of reliable lateral confinement of the 2DEG opens the way to the realization of quantum electronic devices at the LaAlO3/SrTiO3 interface.
Optical pulse generation in single section InAs/GaAs quantum dot edge emitting lasers under continuous wave operation
Authors: Rosales R. , Merghem K. , Calo C. , Bouwmans G. , Krestnikov I. , Martinez A. , Ramdane A.
Published: November 2012

Observation of sub-picosecond pulses from a single section Fabry Perot InAs/GaAs edge emitting quantum dot (QD) based laser at 1.3 μm under continuous wave operation is reported. After group delay dispersion compensation, pulse durations as short as 770 fs in a 45 GHz repetition rate device have been measured, with 1.9 W of peak power and a narrow radio frequency spectrum of only a few kHz linewidth. The experiments show evidence of an unexplored mode locking regime in the InAs/GaAs quantum dot material system, which still needs theoretical modelling and further analysis.
High-quality single crystalline NiO with twin phases grown on sapphire substrate by metalorganic vapor phase epitaxy
Authors: Uchida Kazuo , Yoshida Ken-ichi , Zhang Dongyuan , Koizumi Atsushi , Nozaki Shinji
Published: November 2012

High-quality single crystalline twin phase NiO grown on sapphire substrates by metalorganic vapor phase epitaxy is reported. X-ray rocking curve analysis of NiO films grown at different temperatures indicates a minimum full width at half maximum of the cubic (111) diffraction peak of 0.107° for NiO film grown at as low as 550 °C. Detailed microstructural analysis by Φ scan X-ray diffraction and transmission electron microscopy reveal that the NiO film consists of large single crystalline domains with two different crystallographic orientations which are rotated relative to each other along the [111] axis by 60°. These single crystal domains are divided by the twin phase boundaries.
Giant stability of substituent Co chains in ZnO:Co dilute magnetic oxides
Authors: Zhang Yuebin , Assadi Mohammad H. N. , Li Sean
Published: November 2012

Chemical and magnetic structures of substituent Co ions in ZnO:Co dilute magnetic oxides are investigated by using first-principles density functional calculations of isolated Co, clustered Co-O-Con (n>0) and chained -Co-O-Co-O-. It demonstrates that the substitutional Co ions in ZnO tend to form -Co-O-Co-O- chains or Co-O-Con clusters rather than stay isolated. The most stable structure was identified to be antiferromagnetic -Co-O-Co-O- chains via O on ab plane rather than Co-O-Con clusters. Furthermore, substituent Cu codoping in ZnO is disclosed to suppress the Co's tendency towards chain-like structures or clusters, thus enhancing its homogeneous distribution.
Periodic dark pulse emission induced by delayed feedback in a quantum well semiconductor laser
Authors: Li L. , Tang D. Y. , Xu C. W. , Knize R. J. , Shen D. Y.
Published: November 2012

We report the experimental observation of periodic dark pulse emission in a quantum-well semiconductor laser with delayed optical feedback. We found that under appropriate operation conditions the laser can also emit a stable train of dark pulses. The repetition frequency of the dark pulse is determined by the external cavity length. Splitting of the dark pulse was also observed. We speculate that the observed dark pulse is a kind of temporal cavity soliton formed in the laser.
Lg = 60 nm recessed In0.7Ga0.3As metal-oxide-semiconductor field-effect transistors with Al2O3 insulator
Authors: Kim D.-H. , del Alamo J. A. , Antoniadis D. A. , Li J. , Kuo J.-M. , Pinsukanjana P. , Kao Y.-C. , Chen P. , Papavasiliou A. , King C. , Regan E. , Urteaga M. , Brar B. , Kim T.-W.
Published: November 2012

In this Letter, we report on sub-100 nm recessed In0.7Ga0.3As metal-oxide-semiconductor field-effect transistors (MOSFETs) with outstanding logic and high-frequency performance. The device features ex-situ atomic-layer-deposition (ALD) 2-nm Al2O3 layer on a molecular-beam-epitaxy (MBE) 1-nm InP layer and is fabricated through a triple-recess process. An Lg = 60 nm MOSFET exhibits on-resistance (RON) = 220 Ω-μm, subthreshold-swing (S) = 110 mV/decade, and drain-induced-barrier-lowering (DIBL) = 200 mV/V at VDS = 0.5 V, together with enhancement-mode operation. More importantly, this device displays record maximum transconductance (gm_max) = 2000 μs/μm and current-gain cutoff frequency (fT) = 370 GHz at VDS = 0.5 V, in any III-V MOSFET technology.
A Two-Stage Continuous-Flow Synthesis of Spirooxazine Photochromic Dyes
Authors: York Mark , Edenharter Adriana
Published: November 2012

A continuous-flow process for the synthesis of several known and previously unreported spirooxazine photochromic dyes is reported. The process proceeds via an initial copper catalysed addition of substituted anilines to naphthalene-1,2-dione. This is followed by reaction with 1,3,3-trimethyl-2-methyleneindoline in the presence of hydroxylamine hydrochloride to give the desired spirooxazine products. The photochromic dyes were then cast into lenses to allow a preliminary evaluation of their properties.
Cryptic species within the wheat curl mite Aceria tosichella (Keifer) (Acari : Eriophyoidea), revealed by mitochondrial, nuclear and morphometric data
Authors: Skoracka Anna , Kuczyński Lechosław , Santos de Mendonça Renata , Dabert Mirosława , Szydło Wiktoria , Knihinicki Danuta , Truol Graciela , Navia Denise
Published: November 2012

The wheat curl mite (WCM), Aceria tosichella (Keifer, 1969), is one of the primary pests of wheat and other cereals throughout the world. Traditional taxonomy recognises WCM as a single eriophyoid species; however, a recent study suggested that two genetic lineages of WCM in Australia might represent putative species. Here, we investigate WCM populations from different host plants in Australia, South America and Europe and test the hypothesis that WCM is, in fact, a complex of cryptic species. We used morphological data in combination with nucleotide sequences of the mitochondrial cytochromec oxidase subunitI (COI) and nuclear D2 region of 28S rDNA and internal transcribed spacer region (ITS1, ITS2) sequences. The molecular analyses did not support the monophyly of A. tosichella because the outgroup A. tulipae (Keifer, 1938) is grouped within WCM. The molecular datasets indicated the existence of distinct lineages within WCM, with the distances between lineages corresponding to interspecific divergence. Morphological analyses failed to clearly separate WCM populations and lineages, but completely separated A. tulipae from A. tosichella. The results suggest that what has been recognised historically as a single species is, in fact, a complex of several genetically isolated evolutionary lineages that demonstrate potential as cryptic species. Hence, their discrimination using solely morphological criteria may be misleading. These findings are particularly significant because of the economic importance of WCM as a direct pest and vector of plant viruses.
Corrigendum to: Systematic revision, phylogeny and host plant associations of the Australian endemic genus Mcateella Drake (Hemiptera:Heteroptera:Piesmatidae)
Authors: Elias Michael A. , Cassis Gerasimos
Published: November 2012

A systematic revision of Mcateella is given including the description of seven new species: M. austera, sp. nov., M. coolgardie, sp. nov., M. esperancensis, sp. nov., M. exocarposa, sp. nov., M. kwoki, sp. nov., M. reidi, sp. nov. and M. schuhi, sp. nov. The following species are redescribed: M. elongata Hacker M. gibber Drake, M. interioris Hacker and M. splendida Drake. Mcateella is defined as a monophyletic group on the basis of clavate guard setae and the stridulatory apparatus. Phylogenetic analysis of the Piesmatidae recognised Eopiesma as the sister-taxon relative to the remaining extant Piesmatidae. The ingroup relationships of Mcateella contained one polytomy. Miespa was found to be the sister taxon to Mcateella, positing a transantarctic relationship. Host plant analysis indicates that Mcateella are not all Acacia specialists as stated in the literature but feed on a wide range of angiosperms.
Systematics and biology of the iconic Australian scribbly gum moths Ogmograptis Meyrick (Lepidoptera : Bucculatricidae) and their unique insect–plant interaction
Authors: Horak M. , Day M. F. , Barlow C. , Edwards E. D. , Su Y. N. , Cameron S. L.
Published: November 2012

Many smooth-barked Eucalyptus spp.in south-eastern Australia bear distinctive scribbles caused by the larva of some Ogmograptis spp. However, although these scribbles are conspicuous, the systematics and biology of the genus is poorly known. This has been addressed through detailed field and laboratory studies of the biology of three species (O. racemosa Horak, sp. nov., O. fraxinoides Horak, sp. nov., O. scribula Meyrick) in conjunction with a comprehensive taxonomic revision supported by a molecular phylogeny utilising the mitochondrial Cox1 and nuclear 18S genes. In brief, eggs are laid in bark depressions and the first-instar larvae bore into the bark to the level where the future cork cambium forms (the phellogen). Early-instar larvae bore wide, arcing tracks in this layer before forming a tighter zig-zag-shaped pattern. The second-last instar turns and bores either closely parallel to the initial mine or doubles its width, along the zig-zag-shaped mine. The final instar possesses legs and a spinneret (unlike the earlier instars) and feeds exclusively on callus tissue that forms within the zig-zag-shaped mine formed by the previous instar, before emerging from the bark to pupate at the base of the tree. The scars of mines then become visible scribbles following the shedding of the outer bark. Sequence data confirm the placement of Ogmograptis within the Bucculatricidae, suggest that the larvae responsible for the ‘ghost scribbles’ (raised scars found on smooth-barked eucalypts) are members of the related genus Tritymba Meyrick, and support the morphology-based species groups proposed for Ogmograptis. The formerly monotypic genus Ogmograptis Meyrick is revised and divided into three species groups. Eleven new species are described: Ogmograptis fraxinoides Horak, sp. nov., Ogmograptis racemosa Horak, sp. nov., and Ogmograptis pilularis Horak, sp. nov., forming the scribula group with Ogmograptis scribula Meyrick; Ogmograptis maxdayi Horak, sp. nov., Ogmograptis barloworum Horak, sp. nov., Ogmograptis paucidentatus Horak, sp. nov., Ogmograptis rodens Horak, sp. nov., Ogmograptis bignathifer Horak, sp. nov., and Ogmograptis inornatus Horak, sp. nov., as the maxdayi group; Ogmograptis bipunctatus Horak, sp. nov., Ogmograptis pulcher Horak, sp. nov., Ogmograptis triradiata (Turner), comb. nov., and Ogmograptis centrospila (Turner), comb. nov., as the triradiata group. Ogmograptis notosema (Meyrick) cannot be assigned to a species group as the holotype has not been located. Three unique synapomorphies, all derived from immatures, redefine the family Bucculatricidae, uniting Ogmograptis, Tritymba (both Australian) and Leucoedemia Scoble & Scholtz (African) with Bucculatrix Zeller, which is the sister group of the Southern Hemisphere genera. The systematic history of Ogmograptis and the Bucculatricidae is discussed.
Taxonomy and phylogeny of the Neotropical genus Charadrella Wulp (Diptera, Muscidae)
Authors: Haseyama Kirstern L. F. , de Carvalho Claudio J. B.
Published: November 2012

We revise the Neotropical snail-feeding Charadrella and add two new species to it, one from Bolivia and one from Brazil. Additionally, we perform a cladistic analysis of the genus, based on morphological characters. Parsimony analyses were carried out under equal and implied weights. Our matrix included 25 species from nine Neotropical and three Afrotropical genera, including the snail-feeding Cariocamyia Snyder (Neotropical), Aethiopomyia Malloch, Alluaudinella Giglio-Tos and Ochromusca Bigot (Afrotropical). The following relationships between the species of Charadrella were recovered: (C. albuquerquei (C. macrosoma (C. malacophaga (C. boliviana, sp. nov., C. nambikwara, sp. nov.)))). In our chosen topology, the clade that includes Charadrella has the following topology (Dichaetomyia (Alluaudinella (Ochromusca (Itatingamyia (Cariocamyia, Charadrella))))), supporting the placement of the genus in the Dichaetomyiinae.
Oxygen consumption by bovine granulosa cells with prediction of oxygen transport in preantral follicles
Authors: Li Dongxing , Redding Gabe P. , Bronlund John E.
Published: November 2012

The rate of oxygen consumption by granulosa cells is a key parameter in mathematical models that describe oxygen transport across ovarian follicles. This work measured the oxygen consumption rate of bovine granulosa cells in vitro to be in the range 2.1–3.3 × 10–16 mol cell–1 s–1 (0.16–0.25 mol m–3 s–1). The implications of the rates for oxygen transport in large bovine preantral follicles were examined using a mathematical model. The results indicate that oocyte oxygenation becomes increasingly constrained as preantral follicles grow, reaching hypoxic levels near the point of antrum formation. Beyond a preantral follicle radius of 134 µm, oxygen cannot reach the oocyte surface at typical values of model parameters. Since reported sizes of large bovine preantral follicles range from 58 to 145 µm in radius, this suggests that oocyte oxygenation is possible in all but the largest preantral follicles, which are on the verge of antrum formation. In preantral bovine follicles, the oxygen consumption rate of granulosa cells and fluid voidage will be the key determinants of oxygen levels across the follicle.
The reporting of anal cytology and histology samples: establishing terminology and criteria
Authors: Roberts Jennifer Margaret , Ekman Deborah
Published: November 2012

Our understanding of the human papillomavirus (HPV) related cytomorphology and histopathology of the anal canal is underpinned by our knowledge of HPV infection in the cervix. In this review, we utilise cervical reporting of cytological and histological specimens as a foundation for the development of standardised and evidence-based terminology and criteria for reporting of anal specimens. We advocate use of the Australian Modified Bethesda System 2004 for reporting anal cytology. We propose the use of a two-tiered histological reporting system for noninvasive disease – low-grade and high-grade anal intraepithelial neoplasia. These classification systems reflect current understanding of the biology of HPV and enhance diagnostic reproducibility. Biomarkers such as p16INK4A may prove useful in further improving diagnostic accuracy. Standardisation is important because it will increase the value of the data collected as Australian centres develop programs for screening for anal neoplasia.
Epidemiology, natural history and risk factors for anal intraepithelial neoplasia
Authors: Coutlée François , de Pokomandy Alexandra , Franco Eduardo L.
Published: November 2012

Studies conducted in HIV-seropositive individuals have enhanced our understanding of the natural history of anal intraepithelial neoplasia (AIN) and of factors predictive of progression to high-grade AIN, the immediate precursor to anal cancer. AIN is frequently detected in HIV-seropositive individuals. Factors that increase the risk for AIN include HIV infection, low current or nadir blood CD4+ cell counts, receptive anal intercourse, oncogenic human papillomavirus (HPV) infection, persistent anal HPV infection, multiple HPV type infections and high anal HPV viral load. This review confirms the importance of high-grade AIN in HIV-seropositive individuals and HIV-seronegative men having sex with men.
Anal sex practices in heterosexual and male homosexual populations: a review of population-based data
Authors: Heywood Wendy , Smith Anthony M. A.
Published: November 2012

Anal sex is known to be an important risk factor for anal cancer. Yet compared with vaginal intercourse, little is known about anal sex practices in either heterosexual or male homosexual populations. Of the data that are available, it appears a significant and increasing minority of heterosexuals have ever practised anal intercourse. Among homosexual men, most, but not all, report anal sex, with large proportions of men engaging in both insertive and receptive anal intercourse. The most significant finding of the review was the dearth of population-based data, particularly relating to homosexual men.
Fuel manipulation with herbicide treatments to reduce fire hazard in young pine (Pinus elliottii × P. caribaea) plantations in south-east Queensland, Australia
Authors: Lewis Tom , De Faveri Joanne
Published: November 2012

Wildfire represents a major risk to pine plantations. This risk is particularly great for young plantations (generally less than 10 m in height) where prescribed fire cannot be used to manipulate fuel biomass, and where flammable grasses are abundant in the understorey. We report results from a replicated field experiment designed to determine the effects of two rates of glyphosate (450 g L–1) application, two extents of application (inter-row only and inter-row and row) with applications being applied once or twice, on understorey fine fuel biomass, fuel structure and composition in south-east Queensland, Australia. Two herbicide applications (~9 months apart) were more effective than a once-off treatment for reducing standing biomass, grass continuity, grass height, percentage grass dry weight and the density of shrubs. In addition, the 6-L ha–1 rate of application was more effective than the 3-L ha–1 rate of application in periodically reducing grass continuity and shrub density in the inter-rows and in reducing standing biomass in the tree rows, and application in the inter-rows and rows significantly reduced shrub density relative to the inter-row-only application. Herbicide treatment in the inter-rows and rows is likely to be useful for managing fuels before prescribed fire in young pine plantations because such treatment minimised tree scorch height during prescribed burns. Further, herbicide treatments had no adverse effects on plantation trees, and in some cases tree growth was enhanced by treatments. However, the effectiveness of herbicide treatments in reducing the risk of tree damage or mortality under wildfire conditions remains untested.
Diversification of
doublesex
function underlies morph-, sex-, and species-specific development of beetle horns
Authors: Kijimoto Teiya , Moczek Armin P. , Andrews Justen
Published: November 2012

Sex-specific trait expression is frequently associated with highly variable, condition-dependent expression within sexes and rapid divergence among closely related species. Horned beetles are an excellent example for studying the molecular basis of these phenomena because horn morphology varies markedly among species, between sexes, and among alternative, nutritionally-cued morphs within sexes. In addition, horns lack obvious homology to other insect traits and provide a good opportunity to explore the molecular basis of the rapid diversification of a novel trait within and between species. Here we show that the sex-determination gene
doublesex
(
dsx
) underlies important aspects of horn development, including differences between sexes, morphs, and species. In male
Onthophagus taurus
,
dsx
transcripts were preferentially expressed in the horns of the large, horned morph, and RNAi-mediated knockdown of
dsx
dramatically altered male horn allometry by massively reducing horn development in large males, but not in smaller males. Conversely,
dsx
RNAi induced ectopic, nutrition-sensitive horn development in otherwise hornless females. Finally, in a closely related species (
Onthophagus sagittarius
) that has recently evolved a rare reversed sexual dimorphism,
dsx
RNAi revealed reversed as well as novel
dsx
functions despite an overall conservation of
dsx
expression. This suggests that rapid evolution of
dsx
functions has facilitated the transition from a regular sexual dimorphism to a reversed sexual dimorphism in this species. Our findings add beetle horns to existing examples of a close relationship between
dsx
and sexual trait development, and suggest that
dsx
function has been coopted to facilitate both the evolution of environmentally-cued intrasexual dimorphisms and rapid species divergences in a novel trait.
Jurassic mimicry between a hangingfly and a ginkgo from China
Authors: Wang Yongjie , Labandeira Conrad C. , Shih Chungkun , Ding Qiaoling , Wang Chen , Zhao Yunyun , Ren Dong
Published: November 2012

A near-perfect mimetic association between a mecopteran insect species and a ginkgoalean plant species from the late Middle Jurassic of northeastern China recently has been discovered. The association stems from a case of mixed identity between a particular plant and an insect in the laboratory and the field. This confusion is explained as a case of leaf mimesis, wherein the appearance of the multilobed leaf of
Yimaia capituliformis
(the ginkgoalean model) was accurately replicated by the wings and abdomen of the cimbrophlebiid
Juracimbrophlebia ginkgofolia
(the hangingfly mimic). Our results suggest that hangingflies developed leaf mimesis either as an antipredator avoidance device or possibly as a predatory strategy to provide an antiherbivore function for its plant hosts, thus gaining mutual benefit for both the hangingfly and the ginkgo species. This documentation of mimesis is a rare occasion whereby exquisitely preserved, co-occurring fossils occupy a narrow spatiotemporal window that reveal likely reciprocal mechanisms which plants and insects provide mutual defensive support during their preangiospermous evolutionary histories.
Mitochondrial localization of TIGAR under hypoxia stimulates HK2 and lowers ROS and cell death
Authors: Cheung Eric C. , Ludwig Robert L. , Vousden Karen H.
Published: November 2012

The p53-inducible protein TIGAR (Tp53-induced Glycolysis and Apoptosis Regulator) functions as a fructose-2,6-bisphosphatase (Fru-2,6-BPase), and through promotion of the pentose phosphate pathway, increases NADPH production to help limit reactive oxygen species (ROS). Here, we show that under hypoxia, a fraction of TIGAR protein relocalized to mitochondria and formed a complex with hexokinase 2 (HK2), resulting in an increase in HK2 activity. Mitochondrial localization of TIGAR depended on mitochondrial HK2 and hypoxia-inducible factor 1 (HIF1α) activity. The ability of TIGAR to function as a Fru-2,6-BPase was independent of HK2 binding and mitochondrial localization, although both of these activities can contribute to the full activity of TIGAR in limiting mitochondrial ROS levels and protecting from cell death.
Cellular senescence induced by CD158d reprograms natural killer cells to promote vascular remodeling
Authors: Rajagopalan Sumati , Long Eric O.
Published: November 2012

Natural killer (NK) cells, which have an essential role in immune defense, also contribute to reproductive success. NK cells are abundant at the maternal–fetal interface, where soluble HLA-G is produced by fetal trophoblast cells during early pregnancy. Soluble HLA-G induces a proinflammatory response in primary, resting NK cells on endocytosis into early endosomes where its receptor, CD158d, resides. CD158d initiates signaling through DNA-PKcs, Akt, and NF-κB for a proinflammatory and proangiogenic response. The physiological relevance of this endosomal signaling pathway, and how activation of CD158d through soluble ligands regulates NK cell fate and function is unknown. We show here that CD158d agonists trigger a DNA damage response signaling pathway involving cyclin-dependent kinase inhibitor p21 expression and heterochromatin protein HP1-γ phosphorylation. Sustained activation through CD158d induced morphological changes in NK cell shape and size, and survival in the absence of cell-cycle entry, all hallmarks of senescence, and a transcriptional signature of a senescence-associated secretory phenotype (SASP). SASP is a program that can be induced by oncogenes or DNA damage, and promotes growth arrest and tissue repair. The secretome of CD158d-stimulated senescent NK cells promoted vascular remodeling and angiogenesis as assessed by functional readouts of vascular permeability and endothelial cell tube formation. Retrospective analysis of the decidual NK cell transcriptome revealed a strong senescence signature. We propose that a positive function of senescence in healthy tissue is to favor reproduction through the sustained activation of NK cells to remodel maternal vasculature in early pregnancy.
Forecasting seasonal outbreaks of influenza
Authors: Shaman Jeffrey , Karspeck Alicia
Published: November 2012

Influenza recurs seasonally in temperate regions of the world; however, our ability to predict the timing, duration, and magnitude of local seasonal outbreaks of influenza remains limited. Here we develop a framework for initializing real-time forecasts of seasonal influenza outbreaks, using a data assimilation technique commonly applied in numerical weather prediction. The availability of real-time, web-based estimates of local influenza infection rates makes this type of quantitative forecasting possible. Retrospective ensemble forecasts are generated on a weekly basis following assimilation of these web-based estimates for the 2003–2008 influenza seasons in New York City. The findings indicate that real-time skillful predictions of peak timing can be made more than 7 wk in advance of the actual peak. In addition, confidence in those predictions can be inferred from the spread of the forecast ensemble. This work represents an initial step in the development of a statistically rigorous system for real-time forecast of seasonal influenza.
Antibody WN1 222-5 mimics Toll-like receptor 4 binding in the recognition of LPS
Authors: Gomery Kathryn , Müller-Loennies Sven , Brooks Cory L. , Brade Lore , Kosma Paul , Di Padova Franco , Brade Helmut , Evans Stephen V.
Published: November 2012

Escherichia coliinfections, a leading cause of septic shock, remain a major threat to human health because of the fatal action to endotoxin (LPS). Therapeutic attempts to neutralize endotoxin currently focus on inhibiting the interaction of the toxic component lipid A with myeloid differentiating factor 2, which forms a trimeric complex together with Toll-like receptor 4 to induce immune cell activation. The 1.73-Å resolution structure of the unique endotoxin-neutralizing protective antibody WN1 222-5 in complex with the core region shows that it recognizes LPS of allE. coliserovars in a manner similar to Toll-like receptor 4, revealing that protection can be achieved by targeting the inner core of LPS and that recognition of lipid A is not required. Such interference with Toll-like receptor complex formation opens new paths for antibody sepsis therapy independent of lipid A antagonists.
CCR2 chemokine receptor signaling mediates pain in experimental osteoarthritis
Authors: Miller Rachel E. , Tran Phuong B. , Das Rosalina , Ghoreishi-Haack Nayereh , Ren Dongjun , Miller Richard J. , Malfait Anne-Marie
Published: November 2012

Osteoarthritis is one of the leading causes of chronic pain, but almost nothing is known about the mechanisms and molecules that mediate osteoarthritis-associated joint pain. Consequently, treatment options remain inadequate and joint replacement is often inevitable. Here, we use a surgical mouse model that captures the long-term progression of knee osteoarthritis to longitudinally assess pain-related behaviors and concomitant changes in the innervating dorsal root ganglia (DRG). We demonstrate that monocyte chemoattractant protein (MCP)-1 (CCL2) and its high-affinity receptor, chemokine (C-C motif) receptor 2 (CCR2), are central to the development of pain associated with knee osteoarthritis. After destabilization of the medial meniscus, mice developed early-onset secondary mechanical allodynia that was maintained for 16 wk. MCP-1 and CCR2 mRNA, protein, and signaling activity were temporarily up-regulated in the innervating DRG at 8 wk after surgery. This result correlated with the presentation of movement-provoked pain behaviors, which were maintained up to 16 wk. Mice that lackCcr2also developed mechanical allodynia, but this started to resolve from 8 wk onwards. Despite severe allodynia and structural knee joint damage equal to wild-type mice,Ccr2-null mice did not develop movement-provoked pain behaviors at 8 wk. In wild-type mice, macrophages infiltrated the DRG by 8 wk and this was maintained through 16 wk after surgery. In contrast, macrophage infiltration was not observed inCcr2-null mice. These observations suggest a key role for the MCP-1/CCR2 pathway in establishing osteoarthritis pain.
Evolutionary mode routinely varies among morphological traits within fossil species lineages
Authors: Hopkins Melanie J. , Lidgard Scott
Published: November 2012

Recent studies have revitalized interest in methods for detecting evolutionary modes in both fossil sequences and phylogenies. Most of these studies examine single size or shape traits, often implicitly assuming that single phenotypic traits are adequate representations of species-level change. We test the validity of this assumption by tallying the frequency with which traits vary in evolutionary mode within fossil species lineages. After fitting models of directional change, unbiased random walk, and stasis to a dataset of 635 traits across 153 species lineages, we find that within the majority of lineages, evolutionary mode varies across traits and the likelihood of conflicting within-lineage patterns increases with the number of traits analyzed. In addition, single traits may show variation in evolutionary mode even in situations where the overall morphological evolution of the lineage is dominated by one type of mode. These quantified, stratigraphically based findings validate the idea that morphological patterns of mosaic evolution are pervasive across groups of organisms throughout Earth’s history.
Microfluidic chambers for monitoring leukocyte trafficking and humanized nano-proresolving medicines interactions
Authors: Jones Caroline N. , Dalli Jesmond , Dimisko Laurie , Wong Elisabeth , Serhan Charles N. , Irimia Daniel
Published: November 2012

Leukocyte trafficking plays a critical role in determining the progress and resolution of inflammation. Although significant progress has been made in understanding the role of leukocyte activation in inflammation, dissecting the interactions between different leukocyte subpopulations during trafficking is hampered by the complexity of in vivo conditions and the lack of detail of current in vitro assays. To measure the effects of the interactions between neutrophils and monocytes migrating in response to various chemoattractants, at single-cell resolution, we developed a microfluidic platform that replicates critical features of focal inflammation sites. We integrated an elastase assay into the focal chemotactic chambers (FCCs) of our device that enabled us to distinguish between phlogistic and nonphlogistic cell recruitment. We found that lipoxin A4and resolvin D1, in solution or incorporated into nano–proresolving medicines, reduced neutrophil and monocyte trafficking toward leukotriene B4. Lipoxin A4also reduced the elastase release from homogenous and heterogenous mixtures of neutrophils and monocytes. Surprisingly, the effect of resolvin D1 on heterogenous mixtures was antisynergistic, resulting in a transient spike in elastase activity, which was quickly terminated, and the degraded elastin removed by the leukocytes inside the FCCs. Therefore, the microfluidic assay provides a robust platform for measuring the effect of leukocyte interactions during trafficking and for characterizing the effects of inflammation mediators.
Synthetic spatially graded Rac activation drives cell polarization and movement
Authors: Lin Benjamin , Holmes William R. , Wang C. Joanne , Ueno Tasuku , Harwell Andrew , Edelstein-Keshet Leah , Inoue Takanari , Levchenko Andre
Published: November 2012

Migrating cells possess intracellular gradients of active Rho GTPases, which serve as central hubs in transducing signals from extracellular receptors to cytoskeletal and adhesive machinery. However, it is unknown whether shallow exogenously induced intracellular gradients of Rho GTPases are sufficient to drive cell polarity and motility. Here, we use microfluidic control to generate gradients of a small molecule and thereby directly induce linear gradients of active, endogenous Rac without activation of chemotactic receptors. Gradients as low as 15% were sufficient not only to trigger cell migration up the chemical gradient but to induce both cell polarization and repolarization. Cellular response times were inversely proportional to the steepness of Rac inducer gradient in agreement with a mathematical model, suggesting a function for chemoattractant gradient amplification upstream of Rac. Increases in activated Rac levels beyond a well-defined threshold augmented polarization and decreased sensitivity to the imposed gradient. The threshold was governed by initial cell polarity and PI3K activity, supporting a role for both in defining responsiveness to Rac activation. Our results reveal that Rac can serve as a starting point in defining cell polarity. Furthermore, our methodology may serve as a template to investigate processes regulated by intracellular signaling gradients.
α2 and α3 helices of dystrophin R16 and R17 frame a microdomain in the α1 helix of dystrophin R17 for neuronal NOS binding
Authors: Lai Yi , Zhao Junling , Yue Yongping , Duan Dongsheng
Published: November 2012

Homologous spectrin-like repeats can mediate specific protein interaction. The underlying mechanism is poorly understood. Dystrophin contains 24 spectrin-like repeats. However, only repeats 16 and 17 (R16/17) are required for anchoring neuronal NOS (nNOS) to the sarcolemma. Through an adeno-associated virus-based in vivo binding assay, we found that membrane expression of correctly phased R16/17 was sufficient to recruit nNOS to the sarcolemma in mouse muscle. Utrophin R15/16 is homologous to dystrophin R16/17. Substitution of dystrophin R16/17 microdomains with the corresponding regions of utrophin R15/16 suggests that the nNOS binding site is located in a 10-residue fragment in dystrophin R17 α1 helix. Interestingly, swapping this microdomain back into utrophin did not convey the nNOS binding activity. To identify other structural features that are required for nNOS interaction, we replaced an individual α-helix of dystrophin R16/17 with an equivalent α-helix from another dystrophin repeat. In vitro study with yeast two-hybrid suggests that most α-helices of R16/17, except for the R17 α1 helix, were dispensable for nNOS interaction. Surprisingly, in vivo binding assay showed that α2 and α3 helices of both R16 and R17 were essential for nNOS binding in muscle. We concluded that a microdomain in the α1 helix of dystrophin R17 binds to nNOS in a way uniquely defined by two pairs of the flanking helices. Our results provide an explanation for how structurally similar spectrin-like repeats in dystrophin display selective interaction with nNOS. The results also open new therapeutic avenues to restore defective nNOS homeostasis in dystrophin-null Duchenne muscular dystrophy.
Statistical method for comparing the level of intracellular organization between cells
Authors: Apte Zachary S. , Marshall Wallace F.
Published: November 2012

Systems level approaches to analyzing complex emergent behavior require quantitative characterization of alterations of behavior on both the microscale and macroscale. Here we consider the problem of cellular organization and describe a statistical methodology for quantitative comparison of the internal organization between different populations of similar physical objects, such as cells. This comparison is achieved with several steps of analysis. Starting with three-dimensional or two-dimensional images of cells, images are segmented to identify individual cells. Locations of internal points of interest, such as organelles or proteins, are recorded. To define the configuration of internal points in each cell, the individual cells are subjected to bounded Voronoi tessellation: subdividing the bounded volume or area of the cell into subvolumes determined by the locations of the internal points of interest. A statistical methodology is applied to yield a metric for similarity in degree of organization between populations. We applied this methodology to test whether centrioles play a role in global cellular organization, using mutants of the green algaChlamydomonas reinhardtiiwith known alterations in centriole number, structure, and position as a model system. Comparing mutant populations and wild-type populations revealed a dramatic difference in the degree of organization in the mutant strains. These computational and experimental results provide statistical support for prior observational studies and support the idea that centrioles play a role in generating or maintaining global cellular organization. Our results confirm that this method can be used to sensitively compare the extent and type of organization within cells.