bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo Assessment of Focal Brain Lactate Alterations with NMR Proton Spectroscopy
Authors: Hanstock C. C. , Boisvert D. P. J. , Bendall M. R. , Allen P. S.
Published: February 2011

Spectral editing techniques and localization of 1H signals were applied to monitor lactate accumulation in a circumscribed region of brain damage. The experiments were performed at 2.35 T (100 MHz) in a 40-cm bore magnet. Following unilateral craniectomy in anesthetized adult cats, a two-turn surface coil was positioned over the dural surface. Proton spectra were obtained before and 1–5 h after production of a cortical cold lesion from three curved shells of brain tissue, each ∼3 mm thick. The localized spectrum was obtained from each region with and without spectral difference editing for the lactate CH3 protons, but always with the maximum excitation produced by the semiselective binomial pulse centered on the lactate CH3 resonance. Region 1 represented the damaged area, Region 2 was located immediately below Region 1, and Region 3 was immediately below Region 2. Spin-echo magnetic resonance imaging was used to confirm the relationship between the location of the lesion and the regions from which the spectra were obtained. Spectra obtained without lactate editing showed, in addition to the N-acetylaspartate peak, a large lactate peak in Region 1 after production of the cold lesion. In Regions 2 and 3, changes in lactate were more difficult to assess owing to the presence of a lipid peak at a similar frequency that results from incomplete suppression by the spin-echo pulse sequence alone. Spectra acquired using lactate editing did not contain the lipid peak and clearly showed relatively small lactate accumulations in Regions 2 and 3. Examination of signal intensity profiles through brain images upon which the region of spectral acquisition was highlighted revealed a good consistency between the position of the spectral acquisition region and the appearance of a lactate peak in the spectra. Our results demonstrate that spectrally selective, localized 1H spectra can be obtained for the in vivo evaluation of changes in a single resonance, in this case lactate, which are associated with focal surface lesions of the brain. Moreover, by utilizing a combination of localized spectroscopy and imaging, the anatomical content of the region of spectral acquisition is known.
Low-Frequency Oscillations of Cortical Oxidative Metabolism in Waking and Sleep
Authors: Vern Boris A. , Schuette William H. , Leheta Boris , Juel Vern C. , Radulovacki Miodrag
Published: February 2011

To study the changes in cortical oxidative metabolism and blood volume during behavioral state transitions, we employed reflectance spectrophotometry of the cortical cytochrome c oxidase (cyt aa3) redox state and blood volume in unanesthetized cats implanted with bilateral cortical windows and EEG electrodes. Continuous oscillations in the redox state and blood volume (∼9/min) were observed during waking and sleep. These primarily metabolic oscillations of relatively high amplitude were usually synchronous in homotopic cortical areas, and persisted during barbiturate-induced electrocortical silence. Their mean amplitude and frequency did not vary across different behavioral/EEG states, although the mean levels of cyt aa3 oxidation and blood volume during rapid eye movement (REM) sleep significantly exceeded those during waking and slow-wave sleep. These data suggest the existence of a spontaneously oscillating metabolic phenomenon in cortex that is not directly related to neuroelectric activity. A superimposed increase in cortical oxidative metabolism and blood volume occurs during REM sleep. Experimental data concerning cerebral metabolism and blood flow that are obtained by clinical methods that employ relatively long sample acquisition times should therefore be interpreted with caution.
Computer-Regulated Constant Pressure Ischemia in the Rat: The Animal Model
Authors: Boehme Richard J. , Conger Karl A. , Anderson Michael L.
Published: February 2011

A system permitting computer control of partial ischemia in the normotensive rat brain was developed. Right carotid cannulation and bilateral subclavian artery occlusion made the input of blood to the brain dependent solely on left carotid artery flow. Perfusion pressure was controlled by partial compression of this artery with a balloon. The system can produce a range of partial ischemic states maintaining perfusion pressures from 4 to 20 mm Hg. The adequacy of the servo-control system was evaluated in greater detail at requested perfusion pressures of 7 and 12 mm Hg in 14 male Sprague-Dawley rats (300–450 g). Experimentally obtained cerebral perfusion pressures of 6.84 (SD = 0.25, n = 7) and 11.72 (SD = 0.89, n = 7) mm Hg, respectively, demonstrate the efficacy of the system. CBFs were concurrently measured at four separate bilaterally symmetric anatomic sites (cortex, hippocampus, thalamus, and substantia nigra). Significant intra- and interhemispheric differences were found to exist, with regional flows monitored ipsilaterally to the carotid balloon exceeding those of the opposite hemisphere. In summary, this acute model of cerebral ischemia permits control of perfusion pressure over the entire critical partial ischemic range.
Evaluation of Regional Differences of Tracer Appearance Time in Cerebral Tissues Using [15O]Water and Dynamic Positron Emission Tomography
Authors: Iida H. , Higano S. , Tomura N. , Shishido F , Kanno I. , Miura S. , Murakami M. , Takahashi K. , Sasaki H. , Uemura K.
Published: February 2011

The tracer appearance time relative to the radial artery–sampling site has been evaluated in six brain locations in five human subjects using dynamic positron emission tomography (PET) following the bolus injection of H215O. There was a maximum difference of ± 2 s from the average in each location. T o globally adjust the timing difference between the measured arterial curve and the PET scan, a correction method was developed based on a nonlinear least-squares fitting procedure. This new technique determined the global time delay with an accuracy of ± 0.5 s. On the other hand, the linear backward extrapolation method resulted in a systematic error of 4 s.
Longitudinal Body Composition Data in Exclusively Breast‐Fed Infants: A Multicenter Study
Authors: Fields David A. , Gilchrist Janet M. , Catalano Patrick M. , Giannì Maria L. , Roggero Paola M. , Mosca Fabio
Published: February 2011

Reference %fat and total fat‐free mass data is necessary for evaluating growth in infants. We aimed to develop longitudinal %fat and total fat‐free mass data in infants from birth to 6 months of age. An observational, multicenter, prospective cohort study was conducted with assessments at birth, 1 week, 2 weeks, 1, 2, 3, 4, 5, and 6 months of age. Subjects were exclusively breast‐fed and were enrolled at three centers. Whole‐body composition (i.e., %fat and total fat‐free mass) were assessed using air‐displacement plethysmography (ADP) (PEA POD; Life Measurement, Concord, CA). Maternal prepregnancy BMI, gestational weight gain, and infant anthropometric data were collected. A total of 160 infants (boys = 84) were assessed from birth to 4 months of age. Mean birth weight was 3.46 ± 0.39 kg %fat and fat‐free mass significantly increased from birth to 4 months of age (P < 0.0001). Gender‐specific %fat and total fat‐free mass curves for infants from birth to 4 months of age were created. This study will be beneficial to health‐care professionals in evaluating normal growth and nutritional patterns in the first months of life.
Suppression of superconductivity in epitaxial NbN ultrathin films
Authors: Kang L. , Jin B. B. , Liu X. Y. , Jia X. Q. , Chen J. , Ji Z. M. , Xu W. W. , Wu P. H. , Mi S. B. , Pimenov A. , Wu Y. J. , Wang B. G.
Published: February 2011

This paper studies the suppression of superconducting transition temperature (Tc) of ultrathin NbN film. We fabricated epitaxial NbN superconducting thin films of thicknesses ranging from 2.5 to 100 nm on single crystal MgO (100) substrates by dc magnetron sputtering. We performed structure analyses and measured their electric and far infrared properties. The experimental results were compared with several mechanisms of the suppression of superconductivity proposed in the literature, including the weak localization effect, the proximity effect, and quantum size effect (electron wave leakage model). We found that the electron wave leakage model matches best to the experimental data.
Conformationally selective photodissociation dynamics of propanal cation
Authors: Tao Hongli , Shen Lei , Kim Myung Hwa , Suits Arthur G. , Martinez Todd J.
Published: February 2011

We have previously reported experimental evidence for conformationally selective dissociation of propanal cation that was interpreted, on the basis of ab initio multiple spawning calculations, as arising from distinct dynamics in the excited state manifold of the cation. Two conical intersections (CIs) are accessible from Franck–Condon points on the dark state; however, different conformers prefer different CIs and quench to different regions on the ground state. In this paper, we extend our initial report to include experimental results for the partially deuterated propanal cation as well as detailed characterization of the ground state potential energy surface and statistical calculations of the ground state dissociation dynamics. The DC slice imaging experiments show a bimodal velocity distribution for H elimination with the observed branching ratio of the two channels different for the cis and gauche conformers. H(D)-elimination experiments from deuterated propanal cation support the dissociation mechanism proposed in the earlier report. We further investigate reaction rates on the ground state using Rice–Ramsperger–Kassel–Marcus theory. We find that the experimental results are consistent with a mechanistic picture where the ground state dissociation is statistical, and conformer specificity of the dissociation products arises because of the different populations in distinct ground state isomers after photoexcitation due to ultrafast quenching to the ground state.
A quantum propagator for path-integral simulations of rigid molecules
Authors: Noya Eva G. , Vega Carlos , McBride Carl
Published: February 2011

The expression for the quantum propagator for rigid tops, proposed by Müser and Berne [Phys. Rev. Lett. 77, 2638 (1996)], has been extended to asymmetric tops. Path-integral Monte Carlo simulations are provided that show that the quantum propagator proposed in this work exactly reproduces the rotational energy of free asymmetric tops as evaluated from the partition function. This propagator can subsequently be used in path-integral simulations of condensed phases if a rigid molecular model is used.
Influence of interfacial scattering on giant magnetoresistance in Co/Cu ultrathin multilayers
Authors: Elsafi B. , Trigui F. , Fakhfakh Z.
Published: February 2011

Hood et al. have developed an approach of the two spin channel currents based on the Boltzmann equation to examine the magnetotransport properties of iron based trilayers. We applied this approach to study the magnetoresistance (MR) of Co/Cu multilayers. The in plane MR is calculated numerically at room temperature for correlated quasiperiodic roughness interfaces. Numerical results show the strong dependence of MR with the interface roughness, as well as the influence of the proportion of the electrons removed from the reflected and transmitted beams at the Co/Cu interface on the behavior of the MR. We present also the evolution of the MR as function of copper interlayer thickness. Using this approach, we analyze the experimental results giving the antiferromagnetic maximum of the variation in MR with copper thickness.
Enhanced electron field emission properties by tuning the microstructure of ultrananocrystalline diamond film
Authors: Cheng Hsiu-Fung , Chiang Horng-Yi , Horng Chuang-Chi , Chen Huang-Chin , Wang Chuan-Sheng , Lin I-Nan
Published: February 2011

Synthesis of microcrystalline-ultrananocrystalline composite diamond (MCD-UNCD) films, which exhibit marvelous electron field emission (EFE) properties, was reported. The EFE of MCD-UNCD composite diamond film can be turned on at a low field as 6.5 V/μm and attain large EFE current density about 1.0 mA/cm2 at 30 V/μm applied field, which is better than the EFE behavior of the nondoped planar diamond films ever reported. The MCD-UNCD films were grown by a two-step microwave plasma enhanced chemical vapor deposition (MPECVD) process, including forming an UNCD layer in CH4/Ar plasma that contains no extra H2, followed by growing MCD layer using CH4/H2/Ar plasma that contains large proportion of H2. Microstructure examinations using high resolution transmission electron microscopy shows that the secondary MPECVD process modifies the granular structure of the UNCD layer, instead of forming a large grain diamond layer on top of UNCD films. The MCD-UNCD composite diamond films consist of numerous ultrasmall grains (∼5 nm in size), surrounding large grains about hundreds of nanometer in size. Moreover, there exist abundant nanographites in the interfacial region between the grains that were presumed to form interconnected channels for electron transport, resulting in superior EFE properties for MCD-UNCD composite films.
Depth and lateral resolution of laser-assisted atom probe microscopy of silicon revealed by isotopic heterostructures
Authors: Shimizu Y. , Kawamura Y. , Uematsu M. , Tomita M. , Kinno T. , Okada N. , Kato M. , Uchida H. , Takahashi M. , Ito H. , Ishikawa H. , Ohji Y. , Takamizawa H. , Nagai Y. , Itoh K. M.
Published: February 2011

We report on a direct comparison of the depth and lateral resolution of the current state-of-the-art laser-assisted atom probe microscopy analysis of single-crystalline silicon. The isotopic heterostructures composed of 5–15 nm-thick S28i- and S30i-enriched layers were measured to reconstruct three-dimensional images of S28i and S30i stable isotope distributions in the surface perpendicular and parallel directions for the analysis of the depth and lateral resolution, respectively. The decay length experimentally obtained for the lateral direction is only about twice longer than in the direction, meaning that the lateral resolution is higher than obtained by secondary ion mass spectrometry.
Dispenser printed composite thermoelectric thick films for thermoelectric generator applications
Authors: Madan Deepa , Chen Alic , Wright Paul K. , Evans James W.
Published: February 2011

This paper describes novel processes for preparing thermoelectric composite materials compatible with thick film dispenser printing fabrication processes. Optimization of process parameters to improve thermoelectric properties is introduced. We explore the use of n-type Bi2Te3 and p-type Sb2Te3 materials to achieve properties suitable for use in low cost high aspect ratio microscale thermoelectric generators. Printable thermoelectric inks consisted of dispersed semiconductor powders in an epoxy resin system. Thick films were printed on glass substrates and cured at temperatures ranging from 150 to 350 °C. The best achievable power factors for n-type Bi2Te3-epoxy and p-type Sb2Te3-epoxy composite films were 1.5×10−4 W/m K2 and 8.4×10−4 W/m K2, respectively. Figure of merit (ZT) values for n-type Bi2Te3-epoxy and p-type Sb2Te3-epoxy composites were 0.16 and 0.41, respectively, which are much higher than previously reported ZT values for composite thermoelectric materials.
Inverted organic solar cells comprising a solution-processed cesium fluoride interlayer
Authors: Reinhard Manuel , Hanisch Jonas , Zhang Zhenhao , Ahlswede Erik , Colsmann Alexander , Lemmer Uli
Published: February 2011

We investigate the influence of solution-processed cesium fluoride (CsF) interlayers on the performance of inverted polymer solar cells comprising a blend of poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61-butyric acid methyl ester. The thickness of the CsF layer is optimized in terms of current-voltage characteristics by a variation of the solid content in solution. Capacitance-voltage characteristics reveal a shift of the built-in voltage at the cathode interface by about 0.3 V as compared to devices without a CsF layer, giving rise to an increase in open-circuit voltage by the same value. The vertical distribution of Cs+ and F+ ions is studied by secondary ion mass spectroscopy, indicating a strong diffusion of the alkaline fluoride into the organic layer stack.
Magnetoresistance of single molecular junctions measured by a mechanically controllable break junction method
Authors: Yamada Ryo , Noguchi Motoki , Tada Hirokazu
Published: February 2011

The magnetoresistance of Ni/single benzene-1,4-dithiol/Ni molecular junctions was measured by a mechanically controllable break junction method under a magnetic field. The negative magnetoresistance of the molecular junction as large as 30% and the anisotropic magnetoresistance of atomic contacts and tunnel junctions of Ni as large as 30% were observed.
Anomalous optical selection rule of an organic molecule controlled by extremely localized light field
Authors: Iida Takuya , Aiba Yuta , Ishihara Hajime
Published: February 2011

We have theoretically demonstrated the drastic enhancement of light-induced electric polarization in molecular nondipole type dark states. Its magnitude can exceed that of bright states, even in a nanoscale molecule, due to the spatial correlation between the wave function of the excited states and the localized light field. Moreover, it was clarified that the direct observation of such an anomalous enhancement of dark states in a metal nanogap is possible through near field spectroscopy under one-photon excitation. The results obtained will open the way to single molecule detection methods to reveal the molecular level scheme including parity-forbidden states.
Hole mobility enhancement in In0.41Ga0.59Sb quantum-well field-effect transistors
Authors: Xia Ling , Boos J. Brad , Bennett Brian R. , Ancona Mario G. , del Alamo Jesús A.
Published: February 2011

The impact of ⟨110⟩ uniaxial strain on the characteristics of p-channel In0.41Ga0.59Sb quantum-well field-effect transistors (QW-FETs) is studied through chip-bending experiments. Uniaxial strain is found to affect the linear-regime drain current and the threshold voltage of the FET through the modulation of the hole mobility of the two-dimensional hole gas (2DHG) in the QW-FET. The piezoresistance coefficients of the 2DHG have been determined to be π∥⟨110⟩=1.17×10−10 cm2/dyn and π⊥⟨110⟩=−1.9×10−11 cm2/dyn. The value of π∥⟨110⟩ is 1.5 times that of holes in Si metal-oxide-semiconductor (MOS) field-effect transistors and establishes InGaSb as a promising material system for a future III-V complementary MOS (CMOS) technology.
Late-acting self-incompatibility in Acca sellowiana (Myrtaceae)
Authors: Finatto Taciane , Dos Santos Karine L. , Steiner Neusa , Bizzocchi Leon , Holderbaum Daniel F. , Ducroquet Jean P. H. J. , Guerra Miguel P. , Nodari Rubens O.
Published: February 2011

Acca sellowiana (Berg) Burret is a predominantly allogamous species with hermaphrodite flowers that has barriers to self-fertilisation such as dichogamy by protogyny and self-incompatibility. This study aimed to identify when self-incompatibility occurs in A. sellowiana flowers submitted to self-pollinations. Pollinations were made using nine known self-incompatible accessions in several treatments including manual cross-pollination, manual self-pollination, no pollination and natural pollination. Flowers were pollinated and pistils collected at times ranging from 1 to 30 days after pollination (DAP). In both cross- and self-pollinations the fertilisation occurred from 18 DAP and the zygote was visualised at 24 and 26 DAP, respectively. The abscission of the self-pollinated flowers increased from 26 DAP onwards, when significant differences (P < 0.05) were found for the percentage of abscission among self-pollinated and cross-pollinated flowers. At 30 DAP, 72% of self-pollinated flowers were abscised. The size of ovules and ovaries of self-pollinated flowers showed no significant difference from those of non-pollinated flowers throughout 30 DAP, while those from cross-pollinated flowers were significantly larger (P < 0.05) than the other treatments from 22 and 24 DAP, respectively. After 40 DAP, there was no fruit development in self-pollination and non-pollination treatments. Our study brings greater clarity to the mechanism of self-incompatibility in A. sellowiana, indicating late-acting self-incompatibility occurring through the rejection/abscission of self-pollinated flowers precisely after syngamy and zygote formation.
Contribution of autotrophic and heterotrophic respiration to soil CO2 efflux in Chinese fir plantations
Authors: Tian Dalun , Wang Guangjun , Peng Yuanying , Yan Wende , Fang Xi , Zhu Fan , Chen Xiaoyong
Published: February 2011

Soil respiration (Rs) is overwhelmingly the sum of autotrophic respiration (Ra, root and rhizosphere) and heterotrophic respiration (Rh, microbes and soil fauna). Separating Rs into Ra and Rh components is a major challenge but necessary for understanding the implications of environmental change on soil C cycling and sequestration. In this study, a trenching method was employed to partition Rs sources in Chinese fir plantations in Southern China. Soil CO2 efflux (FCO2) rates were measured using an infrared gas analyser system with soil chambers at the trenched and untrenched (Control) plots from January 2007 to December 2008. Soil temperature (Tsoil) and soil water content (Wsoil) were also measured at the plots during the study period. The results showed that the mean soil FCO2 rate from trenched plots (0.88 ± 0.12 µmol m–2 s–1, mean ± s.e.) was significantly lower than that from untrenched plots (1.22 ± 0.18 µmol m–2 s–1) (P < 0.001) during the study period. Compared with Ra, Rh made a major contribution to annual flux of Rs in Chinese fir forests. The relative proportion of Rh to Rs averaged 76 and 69% in 2007 and 2008, respectively. The seasonal changes of Ra to Rs ratio ranged from 13 to 56% with a mean of 33%. The annual mean Rs was 455 ± 249 gC m–2 year–1 in the study site for the study period, of which Rh and Ra were 330 ± 219 and 125 ± 65 gC m–2 year–1, respectively. Both Rs and Rh was strongly correlated with Tsoil at a 5-cm depth, while Ra had no relationship with Tsoil. Temporal variation in Wsoil had little effect on Rs and Rh. The results indicated that the fluxes of Ra and Rh were controlled by different factors and the microbial communities, compared with roots, were likely more sensitive to global warming in affecting soil C fluxes in Chinese fir ecosystems in subtropical regions.
Rise and fall of sea level in Nauru area over a nodal cycle
Authors: Hussein Muhammad Ali S. , Singh Awnesh , Aung Than
Published: February 2011

The sea level rise issue is one of the major topics that have gained global attention. In particular, its impacts on many Pacific island countries have been more prevalent over the last two decades. The tiny island of Nauru, once a wealthy nation, is no exception to the effect of climate change. With its highest point ~61 m above sea level, and the threat of sea level rise evident, Nauru is under pressure to save itself from sea level rise problem. Sea level data from the AusAID funded South Pacific Sea Level and Climate Monitoring Project will be focussed on despite the fact that the length of data is not sufficiently long. The project was set up in response to concerns raised by Pacific island countries over the potential impacts of an enhanced greenhouse effect on climate and sea levels in the South Pacific for 20 years initially. Based upon 17 years of sea level data from the project, the sea level rise rate in Nauru as at July 2010 was 4.4 mm yr–1. This is at least 2–3 times higher than the global average of 1–2 mm yr–1. Sea level in the Nauru area has risen approximately 7.5 cm since the inception of the project 17 years ago (July 1993). Although there is no significant impact on the sea level trends, it is to be noted that the land is quite stable and the rate of land rising is 0.01 mm yr–1. Although the data length is for the last 17 years, the sea level trend values do not fluctuate significantly since 2002. It simply indicates that the rate of sea level rise in the Nauru region is not accelerating as anticipated by the community.
Bacterial community structure and denitrifier (nir-gene) abundance in soil water and groundwater beneath agricultural land in tropical North Queensland, Australia
Authors: Wakelin Steven A. , Nelson Paul N. , Armour John D. , Rasiah Velupillai , Colloff Matthew J.
Published: February 2011

We explored the microbial ecology of water draining through the soil (lysimeter samples) and in the shallow aquifers (bore samples) underlying sugarcane and banana fields near the Great Barrier Reef (GBR), Australia. Lysimeter and bore water samples were collected and analysed chemically and with DNA fingerprinting methods (PCR-DGGE and clone library sequencing) to characterise the structure of the bacterial community. Bacterial communities in soil water and bore water were distinct (P < 0.05), and a primary factor linked with bacterial community structure was water pH (P < 0.05), particularly in water sampled from lysimeters. Irrespective of treatment, >80% of all rRNA gene sequences originated from proteobacteria. However, groundwater communities differed from those in soil water by greater occurrence of Neisseriales and Comamonadaceae (P < 0.01). qPCR was used to measure copy numbers of the nirK and nirS genes encoding NO-forming nitrite reductases. Copy numbers of both genes were greater in soil water samples than groundwater (P = 0.05), with the difference in nirK being greater under sugarcane than banana. These differences in nirK-gene abundance show that there is greater potential for denitrification in soil water under sugarcane, leading to low concentrations of nitrate in the underlying groundwater. This knowledge can be used towards development of soil and land-use management practices promoting bacterial denitrification in groundwater to lessen the undesirable ecological consequences where groundwater discharges lower in the GBR catchment zones.
Microdissection of neural networks by conditional reporter expression from a Brainbow herpesvirus
Authors: Card J. Patrick , Kobiler Oren , McCambridge Joshua , Ebdlahad Sommer , Shan Zhiying , Raizada Mohan K. , Sved Alan F. , Enquist Lynn W.
Published: February 2011

Transneuronal transport of neurotropic viruses is widely used to define the organization of neural circuitry in the mature and developing nervous system. However, interconnectivity within complex circuits limits the ability of viral tracing to define connections specifically linked to a subpopulation of neurons within a network. Here we demonstrate a unique viral tracing technology that highlights connections to defined populations of neurons within a larger labeled network. This technology was accomplished by constructing a replication-competent strain of pseudorabies virus (PRV-263) that changes the profile of fluorescent reporter expression in the presence of Cre recombinase (Cre). The viral genome carries a Brainbow cassette that expresses a default red reporter in infected cells. However, in the presence of Cre, the red reporter gene is excised from the genome and expression of yellow or cyan reporters is enabled. We used PRV-263 in combination with a unique lentivirus vector that produces Cre expression in catecholamine neurons. Projection-specific infection of central circuits containing these Cre-expressing catecholamine neurons with PRV-263 resulted in Cre-mediated recombination of the PRV-263 genome and conditional expression of cyan/yellow reporters. Replication and transneuronal transport of recombined virus produced conditional reporter expression in neurons synaptically linked to the Cre-expressing catecholamine neurons. This unique technology highlights connections specific to phenotypically defined neurons within larger networks infected by retrograde transneuronal transport of virus from a defined projection target. The availability of other technologies that restrict Cre expression to defined populations of neurons indicates that this approach can be widely applied across functionally defined systems.
Molecular basis for enhancement of the meiotic DMC1 recombinase by RAD51 associated protein 1 (RAD51AP1)
Authors: Dray Eloïse , Dunlop Myun Hwa , Kauppi Liisa , Filippo Joseph San , Wiese Claudia , Tsai Miaw-Sheue , Begovic Sead , Schild David , Jasin Maria , Keeney Scott , Sung Patrick
Published: February 2011

Homologous recombination is needed for meiotic chromosome segregation, genome maintenance, and tumor suppression. RAD51AP1 (RAD51 associated protein 1) has been shown to interact with and enhance the recombinase activity of RAD51. Accordingly, genetic ablation of RAD51AP1 leads to enhanced sensitivity to and also chromosome aberrations upon DNA damage, demonstrating a role for RAD51AP1 in mitotic homologous recombination. Here we show physical association of RAD51AP1 with the meiosis-specific recombinase DMC1 and a stimulatory effect of RAD51AP1 on the DMC1-mediated D-loop reaction. Mechanistic studies have revealed that RAD51AP1 enhances the ability of the DMC1 presynaptic filament to capture the duplex-DNA partner and to assemble the synaptic complex, in which the recombining DNA strands are homologously aligned. We also provide evidence that functional cooperation is dependent on complex formation between DMC1 and RAD51AP1 and that distinct epitopes in RAD51AP1 mediate interactions with RAD51 and DMC1. Finally, we show that RAD51AP1 is expressed in mouse testes, and that RAD51AP1 foci colocalize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination.
Real-time analysis of double-strand DNA break repair by homologous recombination
Authors: Hicks Wade M. , Yamaguchi Miyuki , Haber James E.
Published: February 2011

The ability to induce synchronously a single site-specific double-strand break (DSB) in a budding yeast chromosome has made it possible to monitor the kinetics and genetic requirements of many molecular steps during DSB repair. Special attention has been paid to the switching of mating-type genes in
Saccharomyces cerevisiae
, a process initiated by the HO endonuclease by cleaving the
MAT
locus. A DSB in
MAT
a is repaired by homologous recombination—specifically, by gene conversion—using a heterochromatic donor,
HML
α. Repair results in the replacement of the a-specific sequences (Ya) by Yα and switching from
MAT
a to
MAT
α. We report that
MAT
switching requires the DNA replication factor Dpb11, although it does not require the Cdc7-Dbf4 kinase or the Mcm and Cdc45 helicase components. Using Southern blot, PCR, and ChIP analysis of samples collected every 10 min, we extend previous studies of this process to identify the times for the loading of Rad51 recombinase protein onto the DSB ends at
MAT
, the subsequent strand invasion by the Rad51 nucleoprotein filament into the donor sequences, the initiation of new DNA synthesis, and the removal of the nonhomologous Y sequences. In addition we report evidence for the transient displacement of well-positioned nucleosomes in the
HML
donor locus during strand invasion.
Approaches and frameworks for management and research in small-scale fisheries.
Authors: Andrew N. L. , Evans L.
Published: February 2011

The search for innovations and implementation of research frameworks for small-scale fisheries in developing and least developed countries are discussed.
Developing markets for small-scale fisheries: utilizing the value chain approach.
Authors: Jacinto E. R. , Pomeroy R. S.
Published: February 2011

This chapter describes the constraints for marketing by small-scale fisheries and the steps for market development, including stabilization of the fish supply, setting up cooperatives, enhancing relations in the value chain and building market institutions.
Small-scale fisheries compliance: integrating social justice, legitimacy and deterrence.
Authors: Hauck M.
Published: February 2011

This chapter provides an overview of the development of fisheries compliance thinking and the applicability of this theory to the small-scale fisheries sector. A conceptual framework for understanding small-scale fisheries compliance is presented. Emphasis will be placed on the need to understand fisher behaviour within the context of a fishery system as a whole, and to recognize the role of law and power in influencing the way in which fishers comply with rules and regulations. The preconditions for enhancing small-scale fisheries compliance, namely social justice, legitimacy and deterrence, are also introduced and discussed in detail.
The use of school self‐evaluation results in the Netherlands and Flanders
Authors: Schildkamp Kim , Vanhoof Jan , van Petegem Peter , Visscher Adrie
Published: February 2011

This article presents the results of two studies on the use of school self‐evaluation in the Netherlands and Flanders. It focuses on which forms of instrumental use of school self‐evaluation results can be found in schools, and how differences in self‐evaluation use between schools can be explained. Results show that the instrumental use of self‐evaluation results in both contexts was limited. Results further show that differences in the use of school self‐evaluation results can be explained by differences in school organizational characteristics, implementation characteristics, and the characteristics of the school self‐evaluation itself. Implications for theory, policy, and practice are discussed.
Testing an Optimized Community-Based Human Immunodeficiency Virus (HIV) Risk Reduction and Antiretroviral Adherence Intervention for HIV-Infected Injection Drug Users
Authors: Copenhaver Michael M. , Lee I-Ching , Margolin Arthur , Bruce Robert D. , Altice Frederick L.
Published: February 2011

The authors conducted a preliminary study of the 4-session Holistic Health for HIV (3H+), which was adapted from a 12-session evidence-based risk reduction and antiretroviral adherence intervention. Improvements were found in the behavioral skills required to properly adhere to HIV medication regimens. Enhancements were found in all measured aspects of sex-risk reduction outcomes, including HIV knowledge, motivation to reduce sex-risk behavior, behavioral skills related to engaging in reduced sexual risk, and reduced risk behavior. Improvements in drug use outcomes included enhancements in risk reduction skills as well as reduced heroin and cocaine use. Intervention effects also showed durability from post-intervention to the follow-up assessment point. Females responded particularly well in terms of improvements in risk reduction skills and risk behavior. This study suggests that an evidence-based behavioral intervention may be successfully adapted for use in community-based clinical settings where HIV-infected drug users can be more efficiently reached.
Quetiapine Dependence and Withdrawal: A Case Report
Authors: Yargic Ilhan , Caferov Ceyhun
Published: February 2011

Quetiapine is a new-generation antipsychotic medication approved in the treatment of schizophrenia, bipolar disorder, and related disorders. There are reports about the abuse and possible dependence of quetiapine. We present the first case of definite quetiapine dependence. This is a 37-year-old male who applied to the addiction unit because he could not control quetiapine use. He had a history of alcohol and benzodiazepine dependence as well as cannabis abuse. He reported to have a rush on quetiapine and suffered from its withdrawal when he tried to wean off the medication. This case and similar other suggest that while quetiapine may be beneficial in the treatment of some patients with addictive disorders, we should be cautious when using quetiapine to treat patients with drug or alcohol dependence.
False Recall in the Deese–Roediger–McDermott Paradigm: The Roles of Gist and Associative Strength
Authors: Cann David R. , McRae Ken , Katz Albert N.
Published: February 2011

Theories of false memories, particularly in the Deese–Roediger–McDermott (DRM) paradigm, focus on word association strength and gist. Backward associative strength (BAS) is a strong predictor of false recall in this paradigm. However, other than being defined as a measure of association between studied list words and falsely recalled nonpresented critical words, there is little understanding of this variable. In Experiment 1, we used a knowledge-type taxonomy to classify the semantic relations in DRM stimuli. These knowledge types predicted false-recall probability, as well as BAS itself, with the most important being situation features, synonyms, and taxonomic relations. In three subsequent experiments, we demonstrated that lists composed solely of situation features can elicit a gist and produce false memories, particularly when monitoring processes are made more difficult. Our results identify the semantic factors that underlie BAS and suggest how considering semantic relations leads to a better understanding of gist formation.
Disproportionate Minority Contact in the American Juvenile Justice System: Where are We after 20 Years, a Philosophy Shift, and Three Amendments?
Authors: McCARTER SUSAN A.
Published: February 2011

For the past 20 years, youth of color have been over represented in the American juvenile justice system. Over that same period, the philosophy of the juvenile court has changed from a more informal and rehabilitative model to a more formal and punitive model, and minority youth have experienced disparate and more severe outcomes than their majority counterparts. Starting in 1988, 3 significant policy changes were made via amendments to the JuvenileJustice and Delinquency Prevention Act of 1974 mandating that states address disproportionate minority contact (DMC). The author examined the philosophy shifts in juvenile justice, as well as systemic and DMC policy changes, and their effects on the current status ofminority over representation. Recommendations are presented for social workers to address disproportionate minority contact.
IFT20 is required for opsin trafficking and photoreceptor outer segment development
Authors: Keady Brian T. , Le Yun Zheng , Pazour Gregory J.
Published: February 2011

The light-detecting outer segments of vertebrate photoreceptors are cilia. Like other cilia, all materials needed for assembly and maintenance are synthesized in the cell body and transported into the cilium. The highly elaborated nature of the outer segment and its high rate of turnover necessitate unusually high levels of transport into the cilium. In this work, we examine the role of the IFT20 subunit of the intraflagellar transport (IFT) particle in photoreceptor cells. IFT20 was deleted in developing cones by a cone-specific Cre and in mature rods and cones by a tamoxifen-activatable Cre. Loss of IFT20 during cone development leads to opsin accumulation in the inner segment even when the connecting cilium and outer segment are still intact. With time this causes cone cell degeneration. Similarly, deletion of IFT20 in mature rods causes rapid accumulation of rhodopsin in the cell body, where it is concentrated at the Golgi complex. We further show that IFT20, acting both as part of the IFT particle and independent of the particle, binds to rhodopsin and RG-opsin. Since IFT20 dynamically moves between the Golgi complex and the connecting cilium, the current work suggests that rhodopsin and opsins are cargo for IFT transport.
Dynamic and structural signatures of lamellar actomyosin force generation
Authors: Aratyn-Schaus Yvonne , Oakes Patrick W. , Gardel Margaret L.
Published: February 2011

The regulation of cellular traction forces on the extracellular matrix is critical to cell adhesion, migration, proliferation, and differentiation. Diverse lamellar actin organizations ranging from contractile lamellar networks to stress fibers are observed in adherent cells. Although lamellar organization is thought to reflect the extent of cellular force generation, understanding of the physical behaviors of the lamellar actin cytoskeleton is lacking. To elucidate these properties, we visualized the actomyosin dynamics and organization in U2OS cells over a broad range of forces. At low forces, contractile lamellar networks predominate and force generation is strongly correlated to actomyosin retrograde flow dynamics with nominal change in organization. Lamellar networks build ∼60% of cellular tension over rapid time scales. At high forces, reorganization of the lamellar network into stress fibers results in moderate changes in cellular tension over slower time scales. As stress fibers build and tension increases, myosin band spacing decreases and α-actinin bands form. On soft matrices, force generation by lamellar networks is unaffected, whereas tension-dependent stress fiber assembly is abrogated. These data elucidate the dynamic and structural signatures of the actomyosin cytoskeleton at different levels of tension and set a foundation for quantitative models of cell and tissue mechanics.
Contraception for Older Women
Authors: Gardner Alice
Published: February 2011

As trainee and practising doctors, our training and experience in contraception and sexual health often tends to focus on the prevention of unwanted pregnancy and sexually transmitted infections in younger women. However, although fertility undoubtedly falls in older age, conception rates in older women are increasing: the Office for National Statistics reports that 2008 saw a 5% increase in fertility rates for women aged 40 years and over. Sexually transmitted infections are also seen in older age groups.
Rats Exposed to Isoflurane In Utero during Early Gestation Are Behaviorally Abnormal as Adults
Authors: Palanisamy Arvind , Baxter Mark G. , Keel Pamela K. , Xie Zhongcong , Crosby Gregory , Culley Deborah J.
Published: February 2011

Background

Preclinical evidence suggests that commonly used anesthetic agents induce long-lasting neurobehavioral changes when administered early in life, but there has been virtually no attention to the neurodevelopmental consequences for the fetus of maternal anesthesia. This study tested the hypothesis that fetal rats exposed to isoflurane during maternal anesthesia on gestational day 14, which corresponds to the second trimester in humans, would be behaviorally abnormal as adults.

Methods

Timed, pregnant rats were randomly assigned on gestational day 14 to receive 1.4% isoflurane in 100% oxygen (n = 3) or 100% oxygen (n = 2) for 4 h. Beginning at 8 weeks of age, male offspring (N = 12-14 in control and anesthesia groups, respectively) were evaluated for spontaneous locomotor activity, hippocampal-dependent learning and memory (i.e., spontaneous alternations, novel object recognition, and radial arm maze), and anxiety (elevated plus maze).

Results

Isoflurane anesthesia was physiologically well tolerated by the dams. Adult rats exposed prenatally to isoflurane were not different than controls on spontaneous locomotor activity, spontaneous alternations, or object recognition memory, but made more open arm entries on the elevated plus maze and took longer and made more errors of omission on the radial arm maze.

Conclusions

Rats exposed to isoflurane in utero at a time that corresponds to the second trimester in humans have impaired spatial memory acquisition and reduced anxiety, compared with controls. This suggests the fetal brain may be adversely affected by maternal anesthesia, and raises the possibility that vulnerability to deleterious neurodevelopmental effects of isoflurane begins much earlier in life than previously recognized.
Cell invasion of poultry-associated Salmonella enterica serovar Enteritidis isolates is associated with pathogenicity, motility and proteins secreted by the type III secretion system
Authors: Shah Devendra H. , Zhou Xiaohui , Addwebi Tarek , Davis Margaret A. , Orfe Lisa , Call Douglas R. , Guard Jean , Besser Thomas E.
Published: February 2011

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of food-borne gastroenteritis in humans worldwide. Poultry and poultry products are considered the major vehicles of transmission to humans. Using cell invasiveness as a surrogate marker for pathogenicity, we tested the invasiveness of 53 poultry-associated isolates of S. Enteritidis in a well-differentiated intestinal epithelial cell model (Caco-2). The method allowed classification of the isolates into low (n = 7), medium (n = 18) and high (n = 30) invasiveness categories. Cell invasiveness of the isolates did not correlate with the presence of the virulence-associated gene spvB or the ability of the isolates to form biofilms. Testing of representative isolates with high and low invasiveness in a mouse model revealed that the former were more invasive in vivo and caused more and earlier mortalities, whereas the latter were significantly less invasive in vivo, causing few or no mortalities. Further characterization of representative isolates with low and high invasiveness showed that most of the isolates with low invasiveness had impaired motility and impaired secretion of either flagella-associated proteins (FlgK, FljB and FlgL) or type III secretion system (TTSS)-secreted proteins (SipA and SipD) encoded on Salmonella pathogenicity island-1. In addition, isolates with low invasiveness had impaired ability to invade and/or survive within chicken macrophages. These data suggest that not all isolates of S. Enteritidis recovered from poultry may be equally pathogenic, and that the pathogenicity of S. Enteritidis isolates is associated, in part, with both motility and secretion of TTSS effector proteins.
Role of sphingosine-1-phosphate (S1P) and S1P receptor 2 in the phagocytosis of Cryptococcus neoformans by alveolar macrophages
Authors: McQuiston Travis , Luberto Chiara , Del Poeta Maurizio
Published: February 2011

The pathogenic fungusCryptococcus neoformansis a major cause of morbidity and mortality in immunocompromised individuals. Infection of the human host occurs through inhalation of infectious propagules following environmental exposure. In the lung,C. neoformanscan reside in the extracellular environment of the alveolar spaces or, upon phagocytosis, it can survive and grow intracellularly within alveolar macrophages (AMs). In previous studies, we found that sphingosine kinase 1 (SK1) influenced the intracellular residency ofC. neoformanswithin AMs. Therefore, with this study we aimed to examine the role of the SK1 lipid product, sphingosine-1-phosphate (S1P), in the AMs–C. neoformansinteraction. It was found that extracellular S1P enhances the phagocytosis ofC. neoformansby AMs. Using both genetic and pharmacological approaches we further show that extracellular S1P exerts its effect on the phagocytosis ofC. neoformansby AMs through S1P receptor 2 (S1P2). Interestingly, loss of S1P2 caused a dramatic decrease in the mRNA levels of Fcγ receptors I (FcγRI), -II and -III. In conclusion, our data suggest that extracellular S1P increases antibody-mediated phagocytosis through S1P2 by regulating the expression of the phagocytic Fcγ receptors.