bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical aging of ambient organic aerosol from heterogeneous reaction with hydroxyl radicals
Authors: George I. J. , Slowik J. , Abbatt J. P. D.
Published: July 2008

The chemical transformation of ambient particles due to heterogeneous oxidation was investigated. Ambient aerosol particles sampled in Toronto, Ontario during September and October of 2007 were exposed to OH radicals in a flow tube reactor to simulate relevant atmospheric OH exposures. An Aerodyne Aerosol Mass Spectrometer measured changes in chemical composition and degree of oxidation of reacted ambient particles. Mass spectral changes of ambient particles exposed to OH revealed a loss in the hydrocarbon‐like organic fraction along with an increase in the oxygenated organic fraction. Furthermore, a minor fraction of the organic mass was lost through volatilization at high OH exposure. These observations indicate that an atmospheric OH exposure time of no more than 4 days for a typical OH concentration of 2 × 106 cm−3 causes enhanced oxidation of the organic matter in ambient particles. Therefore, heterogeneous oxidation may be an important chemical transformation pathway for ambient particles during regional transport.
Measurement of the mixing state, mass, and optical size of individual black carbon particles in urban and biomass burning emissions
Authors: Schwarz J. P. , Gao R. S. , Spackman J. R. , Watts L. A. , Thomson D. S. , Fahey D. W. , Ryerson T. B. , Peischl J. , Holloway J. S. , Trainer M. , Frost G. J. , Baynard T. , Lack D. A. , de Gouw J. A. , Warneke C. , Del Negro L. A.
Published: July 2008

In situ measurements of the mass, mixing state, and optical size of individual black‐carbon (BC) particles in the fine mode (90–600 nm) have been made in fresh emissions from urban and biomass burning sources with an airborne single‐particle soot photometer. Contrasts between the two sources are significant and consistent. Urban BC tends to smaller sizes, fewer coated particles, thinner coatings, and less absorption per unit mass than biomass‐burning BC. This suggests that urban BC may have a longer lifetime in the atmosphere and a different impact on BC radiative forcing in the first indirect effect than biomass‐burning BC. These measurements bound the likely variability in the microphysical state of BC emissions from typical continental processes, and provide direct measurements of the size distribution and coating state of fine‐mode BC for use in constraining climate and aerosol models. These results highlight the need for the integration of source‐specific information into such models.
Mineralogy‐based quantitative precipitation and temperature reconstructions from annually laminated lake sediments (Swiss Alps) since AD 1580
Authors: Trachsel M. , Eggenberger U. , Grosjean M. , Blass A. , Sturm M.
Published: July 2008

We present quantitative autumn, summer and annual precipitation and summer temperature reconstructions from proglacial annually laminated Lake Silvaplana, eastern Swiss Alps back to AD 1580. We used X‐ray diffraction peak intensity ratios of minerals in the sediment layers (quartz qz, plagioclase pl, amphibole am, mica mi) that are diagnostic for different source areas and hydro‐meteorological transport processes in the catchment. XRD data were calibrated with meteorological data (AD 1800/1864–1950) and revealed significant correlations: mi/pl with SON precipitation (r = 0.56, p < 0.05) and MJJAS precipitation (r = 0.66, p < 0.01); qz/mi with MJJAS temperature (r = −0.72, p < 0.01)and qz/am with annual precipitation (r = −0.54, p < 0.05). Geological catchment settings and hydro‐meteorological processes provide deterministic explanations for the correlations. Our summer temperature reconstruction reproduces the typical features of past climate variability known from independent data sets. The precipitation reconstructions show a LIA climate moister than today. Exceptionally wet periods in our reconstruction coincide with regional glacier advances.
Oceanic alkyl nitrates as a natural source of tropospheric ozone
Authors: Neu Jessica L. , Lawler Michael J. , Prather Michael J. , Saltzman Eric S.
Published: July 2008

Observations have revealed widespread emissions of alkyl nitrates from the tropical and Southern Oceans. We present the first chemical transport model simulations to examine the global impact of these emissions. Matching observed atmospheric abundances, we derive a total oceanic flux of methyl nitrate (MeONO2) and ethyl nitrate (EtONO2) equivalent to 0.35 Tg of N per year, which contributes as much as 1 DU to the tropospheric ozone column in the Western Pacific and is responsible for about 3% of the global oxidative capacity of the troposphere.
Electron densities in the upper ionosphere of Mars from the excitation of electron plasma oscillations
Authors: Duru F. , Gurnett D. A. , Morgan D. D. , Modolo R. , Nagy A. F. , Najib D.
Published: July 2008

In addition to remote radio sounding of the ionosphere of Mars, the MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) instrument on the Mars Express spacecraft is also able to measure the in situ electron density from the excitation of local electron plasma oscillations. This paper presents an investigation of the electron density in the upper ionosphere of Mars based on the frequency of these oscillations. The advantage of this method is that electron densities can be measured at much higher altitudes than can be determined from remote radio soundings. Using this technique electron densities from 503 orbits have been analyzed over the period from 4 August 2005 to 31 July 2007 for altitudes ranging from about 275 to 1300 km. Although there is considerable variability from orbit to orbit, the median electron density at a given solar zenith angle (SZA) on the dayside of Mars decreases systematically with increasing altitude with a characteristic plasma scale height varying from about 80 to 145 km. At a fixed altitude, the electron density remains almost constant for SZAs less than about 80°. For SZAs greater than about 80° the electron density decreases rapidly with increasing SZA, approaching very low values on the nightside. Simulations performed using both magnetohydrodynamic and hybrid codes show that the nearly constant density at a given altitude is caused by the horizontal transport of plasma from the dayside toward the nightside due to interaction with the solar wind.
l-Arginine Decreases Fluid-Percussion Injury-Induced Neuronal Nitrotyrosine Immunoreactivity in Rats
Authors: Avila Marcela A , Sell Stacy L , Kadoi Yuji , Prough Donald S , Hellmich Helen L , Velasco Marco , Dewitt Douglas S
Published: July 2008

Peroxynitrite is a powerful oxidant capable of nitrating phenolic moieties, such as tyrosine or tyrosine residues in proteins and increases after traumatic brain injury (TBI). First, we tested the hypothesis that TBI increases nitrotyrosine (NT) immunoreactivity in the brain by measuring the number of NT-immunoreactive neurons in the cerebral cortex and hippocampus of rats subjected to parasagittal fluid-percussion TBI. Second, we tested the hypothesis that treatment with l-arginine, a substrate for nitric oxide synthase, further increases NT immunoreactivity over TBI alone. Rats were anesthetized with isoflurane and subjected to TBI, sham TBI, or TBI followed by treatment with l-arginine (100 mg/kg). Twelve, 24, or 72 h after TBI, brains were harvested. Coronal sections (10 μm) were incubated overnight with rabbit polyclonal anti-NT antibody, rinsed, and incubated with a biotinylated secondary antibody. The antigen—antibody complex was visualized using a peroxidase-conjugated system with diaminobenzidine as the chromagen. The number of NT-positive cortical and hippocampal neurons increased significantly in both ipsilateral and contralateral hemispheres up to 72 h after TBI compared with the sham-injured group. Remarkably, treatment with l-arginine reduced the number of NT-positive neurons after TBI in both cortex and hippocampus. Our results indicate that l-arginine actually prevents TBI-induced increases in NT immunoreactivity.
Roscovitine Reduces Neuronal Loss, Glial Activation, and Neurologic Deficits after Brain Trauma
Authors: Hilton Genell D , Stoica Bogdan A , Byrnes Kimberly R , Faden Alan I
Published: July 2008

Traumatic brain injury (TBI) causes both direct and delayed tissue damage. The latter is associated with secondary biochemical changes such as cell cycle activation, which leads to neuronal death, inflammation, and glial scarring. Flavopiridol—a cyclin-dependent kinase (CDK) inhibitor that is neither specific nor selective—is neuroprotective. To examine the role of more specific CDK inhibitors as potential neuroprotective agents, we studied the effects of roscovitine in TBI. Central administration of roscovitine 30 mins after injury resulted in significantly decreased lesion volume, as well as improved motor and cognitive recovery. Roscovitine attenuated neuronal death and inhibited activation of cell cycle pathways in neurons after TBI, as indicated by attenuated cyclin G1 accumulation and phosphorylation of retinoblastoma protein. Treatment also decreased microglial activation after TBI, as reflected by reductions in ED1, galectin-3, p22PHOX, and Iba-1 levels, and attenuated astrogliosis, as shown by decreased accumulation of glial fibrillary acidic protein. In primary cortical microglia and neuronal cultures, roscovitine and other selective CDK inhibitors attenuated neuronal cell death, as well as decreasing microglial activation and microglial-dependent neurotoxicity. These data support a multifactorial neuroprotective effect of cell cycle inhibition after TBI—likely related to inhibition of neuronal apoptosis, microglial-induced inflammation, and gliosis—and suggest that multiple CDKs are potentially involved in this process.
Mutations in a small region of the exportin Crm1p disrupt the daughter cell‐specific nuclear localization of the transcription factor Ace2p in Saccharomyces cerevisiae
Authors: Bourens Myriam , Racki Waldemar , Bécam Anne‐Marie , Panozzo Cristina , Boulon Séverine , Bertrand Edouard , Herbert Christopher J.
Published: July 2008

Background information. The CBK1 gene of Saccharomyces cerevisiae encodes a protein kinase that is a member of the NDR (nuclear Dbf2‐related) family of protein kinases, which are involved in morphogenesis and cell proliferation. Previous studies have shown that deletion of CBK1 leads to a loss of polarity and the formation of large aggregates of cells. This aggregation phenotype is due to the loss of the daughter cell‐specific accumulation of the transcription factor Ace2p, which is responsible for the transcription of genes whose products are necessary for the final separation of the mother and the daughter at the end of cell division.

Results. We show that the daughter cell‐specific localization of Ace2p does not occur via a specific localization of the ACE2 mRNA and that, in vivo, the transcription of CTS1, one of the principal targets of Ace2p, is daughter cell‐specific. We have shown that extragenic suppressors of the Δcbk1 aggregation phenotype are located in the nuclear exportin CRM1 and ACE2. These mutations disrupt the interaction of Ace2p and Crm1p, thus impairing Ace2p export and resulting in the accumulation of the protein in both mother and daughter cell nuclei.

Conclusions. We propose that in the daughter cell nucleus Cbk1p phosphorylates the Ace2p nuclear export signal, and that this phosphorylation blocks the export of Ace2p via Crm1p, thus promoting the daughter cell‐specific nuclear accumulation of Ace2p.
mRNA journey to the cytoplasm: attire required
Authors: Rougemaille Mathieu , Villa Tommaso , Gudipati Rajani Kanth , Libri Domenico
Published: July 2008

In eukaryotes, copying the genetic information from a DNA template into RNA is not sufficient itself to confer functional competence to the DNA‐encoded message. mRNAs have to be processed by enzymes and packaged with proteins within nuclei to generate mRNP (messenger ribonucleoprotein) particles, before these can be exported to the cytoplasm. Processing and packaging factors are believed to interact with the nascent mRNA co‐transcriptionally, which protects the highly reactive RNA molecule from a presumably aggressive nuclear environment while providing early commitment to its functional fate. In this review, we will describe the factors that are believed to provide the appropriate ‘dress code’ to the mRNA and the mechanisms underlying the proofreading events that guarantee its quality, focusing on yeast as a model system.
Expression of fibroblast growth factor receptors during development and regression of the bovine corpus luteum
Authors: Guerra D. M. , Giometti I. C. , Price C. A. , Andrade P. B. , Castilho A. C. , Machado M. F. , Ripamonte P. , Papa P. C. , Buratini J.
Published: July 2008

There is evidence that fibroblast growth factors (FGFs) are involved in the regulation of growth and regression of the corpus luteum (CL). However, the expression pattern of most FGF receptors (FGFRs) during CL lifespan is still unknown. The objective of the present study was to determine the pattern of expression of ‘B’ and ‘C’ splice variants of FGFRs in the bovine CL. Bovine CL were collected from an abattoir and classed as corpora hemorrhagica (Stage I), developing (Stage II), developed (Stage III) or regressed (Stage IV) CL. Expression of FGFR mRNA was measured by semiquantitative reverse transcription-polymerase chain reaction and FGFR protein was localised by immunohistochemistry. Expression of mRNA encoding the ‘B’ and ‘C’ spliced forms of FGFR1 and FGFR2 was readily detectable in the bovine CL and was accompanied by protein localisation. FGFR1C and FGFR2C mRNA expression did not vary throughout CL lifespan, whereas FGFR1B was upregulated in the developed (Stage III) CL. FGFR3B, FGFR3C and FGFR4 expression was inconsistent in the bovine CL. The present data indicate that FGFR1 and FGFR2 splice variants are the main receptors for FGF action in the bovine CL.
Postnatal Sertoli and Leydig cell proliferation and the establishment of puberty and sexual maturity in Chinchilla lanigera (Rodentia, Chinchillidae)
Authors: Leal Marcelo C. , França Luiz R.
Published: July 2008

The Chilean chinchilla (Chinchilla lanigera) is threatened in its natural habitat and there is very little information concerning the reproductive biology of this species. Our main objectives were to investigate the postnatal testis development in this rodent, with emphasis on Sertoli and Leydig cell proliferation and the establishment of puberty and sexual maturity. Forty-four animals from one day to 30 months of age had their testis and epididymis prepared (time of collection for animals from 5 to 30 months of age, May–November in the southern hemisphere) for histological and stereological analyses. Both Sertoli and Leydig cell proliferation occurred up to two months after birth and their total number per testis were stable thereafter. Based on spermatid release from the seminiferous epithelium and the presence of sperm in the epididymis, puberty in chinchilla took place at around three months of age. However, testis weight and tubular diameter and epithelium height appeared to stabilise only after the animals reached 17 months of age, indicating that the establishment of full sexual maturity in this species takes a relatively long period of time. This particular finding indicates that chinchilla might represent an interesting experimental model to investigate the mechanisms that regulate the establishment of this important event of reproductive physiology in mammals.
Expression and compartmentalisation of the glycolytic enzymes GAPDH and pyruvate kinase in boar spermatogenesis
Authors: Feiden Sandra , Wolfrum Uwe , Wegener Gerhard , Kamp Günter
Published: July 2008

Boar spermatozoa contain isoforms of both glyceraldehyde 3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) and pyruvate kinase (PK, EC 2.7.1.40). The sperm-specific forms, GAPDH-S and PK-S, are tightly bound to cell structures. By immunofluorescence microscopy GAPDH-S and PK-S were localised in the principal piece of the boar sperm flagellum as well as in the acrosomal region of the sperm head and at the head–midpiece junction. The midpiece of the flagellum, however, contains isoforms of GAPDH and PK that were only recognised by antibodies against somatic GAPDH and PK, respectively, but not by the antibodies against GAPDH-S and PK-S. In sections of boar testis, GAPDH-S and PK-S were first detected in elongating spermatids when both the developing flagellum and the head were labelled with antibodies against GAPDH-S and PK-S. In contrast, antibodies against rabbit muscle GAPDH and PK labelled all developmental stages of germ cells and also neighbouring contractile cells. Thus, the structure-bound sperm-specific enzymes, GAPDH-S and PK-S, appeared only late in spermatogenesis simultaneously with the development of the structures to which they are bound. Anchoring glycolytic enzymes to structures in these mitochondria-free regions may secure ATP-production for both motility and acrosome function.
Glucose can reverse the effects of acute fasting on mouse ovulation and oocyte maturation
Authors: Yan Jun , Zhou Bo , Yang Jie , Tai Ping , Chen Xiufen , Zhang Hua , Zhang Meijia , Xia Guoliang
Published: July 2008

Food deprivation suppresses ovulation. Although nutritional elements are responsible for this suppression, it is not clear whether energy metabolism has any effect on oocyte development under these circumstances. The aim of the present study was to determine which nutritional element is responsible for the effect of acute fasting on mouse ovulation and how oocyte development is affected. The results demonstrate that 64 h food deprivation blocks mouse ovulation. This was reversed by glucose feeding, oil feeding or short-term feeding, all of which elevated serum glucose levels. Furthermore, 48 h food deprivation inhibited follicle-stimulating hormone-induced oocyte maturation in vitro. However, 48 h glucose feeding increased serum glucose levels and restored oocyte maturation. Food deprivation increased serum progesterone levels and decreased serum oestradiol levels. Food deprivation also impaired follicle development, caused the death of oocytes and attenuated glucose consumption by cumulus–oocyte complexes. Taken together, the results indicate that: (1) the suppression of ovulation by acute fasting may be due to the control of oocyte development; and (2) maintaining serum glucose concentrations at a certain level is important for normal ovulation.
Dimethylacetamide can be used as an alternative to glycerol for the successful cryopreservation of koala (Phascolarctos cinereus) spermatozoa
Authors: Zee Yeng Peng , Holt William V. , Gosalvez Jaime , Allen Camryn D. , Nicolson Vere , Pyne Michael , Burridge Michelle , Carrick Frank N. , Johnston Stephen D.
Published: July 2008

Swelling of koala sperm chromatin following cryopreservation has largely been attributed to the absence of intermolecular disulfide cross-linkages in the marsupial sperm nucleus. Fish spermatozoa also lack disulfide bonds within their chromatin, but have been successfully cryopreserved. The present study examined the hypothesis that the cryoprotectants used for fish sperm cryopreservation would confer a similar degree of protection on koala spermatozoa. Three concentrations each of five cryoprotectants (dimethyl sulfoxide, methanol, propylene glycol, ethylene glycol and dimethylacetamide (DMA)) were evaluated. Each treatment was compared against an established koala sperm cryopreservation protocol that uses 14% glycerol. Post-thaw assessment of progressive motility, plasma membrane integrity and mitochondrial membrane potential (MMP) revealed that protocols using 15% DMA achieved 62.2 ± 3.6% (P < 0.05) sperm survival, of which 79% (P < 0.05) had high MMP, an improvement of 32% and 40%, respectively, over sperm frozen in 14% glycerol. The percentage of spermatozoa with swollen nuclei was also lowest when frozen in 15% DMA, both immediately after thawing (18.0 ± 3.5%; P < 0.05) and after 2 h incubation at 35°C (35.8 ± 4.4%; P < 0.05). A second study was conducted to determine the optimal concentration of DMA for use in the cryopreservation of koala spermatozoa. High DMA concentrations (17.5% and 20%) resulted in significantly lower proportions of live spermatozoa showing high MMP immediately after thawing compared with spermatozoa frozen in the lower concentrations. The percentage of koala spermatozoa with swollen chromatin following cryopreservation was not affected by DMA concentration.
Mechanisms of oxidative stress in porcine oocytes and the role of anti-oxidants
Authors: Whitaker B. D. , Knight J. W.
Published: July 2008

The mechanisms of oxidative stress in in vitro maturing porcine oocytes and the effects of anti-oxidant supplementation of the medium in ameliorating these effects were investigated in the present study. In addition to intracellular reduced glutathione (GSH) concentrations and DNA fragmentation, the present study focused on superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase activity. The anti-oxidants used were N-acetylcysteine (NAC) and its derivative NAC-amide (NACA). The results indicate that when SOD is inhibited, supplementation of the maturarion medium with 1.5 mm NAC or NACA compensates for the decrease in SOD activity by reducing the degree of DNA fragmentation (P < 0.05). When GPx is inhibited, supplementation of the maturarion medium with 1.5 mm NAC alleviates the effects of no GPx activity, as indicated by a decrease in the degree of DNA fragmentation (P < 0.05). When the maturarion medium was supplemented with 1.5 mm NACA, intracellular GSH concentrations decreased (P < 0.05) and SOD and catalase activities increased (P < 0.05) along with the degree of DNA fragmentation. These results indicate that the mechanisms of alleviating oxidative stress in porcine oocytes are very complex and supplementing maturing oocytes with anti-oxidants may enhance enzyme activities and eliminate free radicals.
Characterisation of pulses of 13,14-dihydro-15-keto-PGF2alpha (PGFM) and relationships between PGFM pulses and luteal blood flow before, during, and after luteolysis in mares
Authors: Ginther O. J. , Rodrigues B. L. , Ferreira J. C. , Araujo R. R. , Beg M. A.
Published: July 2008

Blood collections for characterising 13,14-dihydro-15-keto-PGF2alpha (PGFM) pulses in mares and colour-Doppler examinations for estimating percentage of corpus luteum with blood-flow signals were done hourly for a 24-h session on Day 15 (ovulation = Day 0; n = 13 mares) or during 12-h sessions from Days 12 to 16 (n= 10 mares). Luteolysis was defined as extending from the beginning of a precipitous decrease in progesterone until progesterone was <2 ng mL–1. Comparisons were made among preluteolysis, luteolysis, and postluteolysis. Greater prostaglandin F2α activity (mean PGFM concentration per session) occurred during luteolysis than during preluteolysis and postluteolysis. Statistically-detected PGFM pulses were smaller during preluteolysis with a highly variable interval from the last pulse to the beginning of luteolysis. Either two or three pulses were detected in each 24-h session during luteolysis and postluteolysis, after excluding three of eight sessions with no pulses during postluteolysis. Statistically, 17% of pulses during postluteolysis were prominent outliers. The nadir-to-nadir interval during a pulse (5 h), the peak-to-peak interval between pulses (9 h), and the resulting 4-h gap between pulses were similar during and after luteolysis. The decrease in progesterone encompassed the PGFM pulses, without a detectable fluctuation during a pulse. The percentage of corpus luteum with blood-flow signals did not change during the ascending portion of a PGFM pulse and decreased within 2 or 3 h after the peak, even during preluteolysis. Results indicated that a reported increase in luteal blood flow in heifers during the ascending portion of a PGFM pulse does not occur in mares.
Molecular basis for the thiol sensitivity of insulin-degrading enzyme
Authors: Neant-Fery Marie , Garcia-Ordoñez Rubén D. , Logan Todd P. , Selkoe Dennis J. , Li Lilin , Reinstatler Lael , Leissring Malcolm A.
Published: July 2008

Insulin-degrading enzyme (IDE) is a ubiquitous zinc-metalloprotease that hydrolyzes several pathophysiologically relevant peptides, including insulin and the amyloid β-protein (Aβ). IDE is inhibited irreversibly by compounds that covalently modify cysteine residues, a mechanism that could be operative in the etiology of type 2 diabetes mellitus (DM2) or Alzheimer's disease (AD). However, despite prior investigation, the molecular basis underlying the sensitivity of IDE to thiol-alkylating agents has not been elucidated. To address this topic, we conducted a comprehensive mutational analysis of the 13 cysteine residues within IDE. Our analysis implicates C178, C812, and C819 as the principal residues conferring thiol sensitivity. The involvement of C812 and C819, residues quite distant from the catalytic zinc atom, provides functional evidence that the active site of IDE comprises two separate domains that are operational only in close apposition. Structural analysis and other evidence predict that alkylation of C812 and C819 disrupts substrate binding, whereas alkylation of C178 interferes with the apposition of active-site domains and subtly repositions zinc-binding residues. Unexpectedly, alkylation of C590 was found to activate hydrolysis of Aβ significantly, while having no effect on insulin, demonstrating that chemical modulation of IDE can be both bidirectional and highly substrate selective. Our findings resolve a long-standing riddle about the basic enzymology of IDE with important implications for the etiology of DM2 and AD. Moreover, this work uncovers key details about the mechanistic basis of the unusual substrate selectivity of IDE that may aid the development of pharmacological agents or IDE mutants with therapeutic value.
Identifying a property of origins of DNA synthesis required to support plasmids stably in human cells
Authors: Wang Chen-Yu , Sugden Bill
Published: July 2008

The plasmid origin of replication,
oriP
, of Epstein–Barr Virus (EBV) was identified in an assay to detect autonomously replicating sequences (ARSs) in human cells. Raji ori, a second origin in EBV, functions
in vivo
but fails in long-term ARS assays. We examined the initiating element, DS, within
oriP
and Raji ori to resolve this paradox. DS, but not Raji ori, binds EBNA1; whereas both act as ARSs in short-term assays, with DS being more efficient, only DS can act as an ARS in long-term assays. Surprisingly, we found that DS supported the establishment of a plasmid with Raji ori
in cis
and that after deletion of DS, Raji ori could now act as an ARS in the long term. This finding explains the frequent failure of ARS assays in mammalian cells. More origins can initially act as ARSs than can be established. We identified one requirement for ARSs to be established: They must function efficiently enough initially to generate a wide distribution of numbers of plasmids per cell. Only the cells that have more than a threshold number of plasmids can survive selections imposed on the cells to retain these replicons.
Effects of Naltrexone During the Descending Limb of the Blood Alcohol Curve
Authors: Ray Lara A. , Hutchison Kent E. , MacKillop James , Miranda Robert , Audette Amy , Swift Robert , Monti Peter M.
Published: July 2008

The neuropharmacological effects of alcohol are known to vary by limb of the blood alcohol curve, yet human laboratory studies of alcoholism pharmacotherapies have largely failed to consider limb of intoxication when examining medication effects on subjective responses to alcohol. This study examined the effects of naltrexone compared to placebo on subjective responses to alcohol at the descending limb of the blood alcohol curve following a controlled intravenous (IV) alcohol administration. Non‐treatment‐seeking hazardous drinkers (n = 38) completed two double‐blind counterbalanced IV alcohol challenge sessions, one after taking naltrexone (50 mg) for three days and one after taking a placebo for three days. During each session, participants reported on subjective responses to alcohol during the descending limb of the blood alcohol curve. Analyses revealed significant main effects of naltrexone, reflecting significantly decreased alcohol‐induced stimulation, craving, vigor, positive mood, and alcohol “high” and increased tension as compared to placebo. These findings suggest that naltrexone may exert some of its therapeutic effects via alterations to experiential aspects of intoxication during the descending limb of alcohol intoxication. Additionally, these results highlight the potential utility of considering limb of blood alcohol curve when examining the mechanisms of action of pharmacotherapies thought to alter subjective responses to alcohol.
Pathways to Change: The Effect of a Web Application on Treatment Interest
Authors: Lieberman Daniel Z. , Massey Suena H.
Published: July 2008

Most individuals with drinking problems do not receive treatment, generally because they do not perceive the need for it. It is difficult to access this population of problem drinkers in order to encourage treatment‐seeking. A Web‐based program was written, designed to increase motivation for change. The program guided non‐treatment‐seekers through a multi‐stage assessment and provided them with feedback. The level of interest in treatment was measured pre‐and post‐intervention. Compared to baseline, after the intervention, significantly more individuals rated themselves “very interested” in participating in some form of traditional treatment (19% vs. 28%), and their focus on a specific modality increased.
Preliminary Study of Buprenorphine and Bupropion for Opioid‐Dependent Smokers
Authors: Mooney Marc E. , Poling James , Gonzalez Gerardo , Gonsai Kishor , Kosten Thomas , Sofuoglu Mehmet
Published: July 2008

In this double‐blind, placebo‐controlled trial, bupropion (BUPRO, 300 mg/day) was compared to placebo (PBO) for the concurrent treatment of opioid and tobacco addiction in 40 opioid‐dependent smokers stabilized on buprenorphine (BUPRE, 24 mg/day). Participants received contingent, monetary reinforcement for abstinence from smoking, illicit opioids, and cocaine. Significant differences in treatment retention were observed (BUPRE+BUPRO, 58%; BUPRE+PBO, 90%). BUPRO treatment was not more effective than placebo for abstinence from tobacco, opioids, or cocaine in BUPRE‐stabilized patients. These preliminary findings do not support the efficacy of BUPRO, in combination with BUPRE, for the concurrent treatment of opioid and tobacco addiction.
Gender Differences in Self‐Reported Drinking‐Induced Disinhibition of Sexual Behaviors
Authors: Hesse Morten , Tutenges Sébastien
Published: July 2008

Sex and drinking go hand‐in‐hand in Western societies. Men also tend to report more sexual disinhibition under the influence of alcohol and drugs than women. At a vacation resort, we conducted a survey of young men and women regarding self‐reported alcohol‐related sexual disinhibition (ARSD), and we administered the Drinking‐Induced Disinhibition Scale (DIDS). We made several comparisons of behavioral patterns using the ARSD scale of the DIDS for each gender: kissing or having sex vs. no sexual contact, or having sex versus kissing or no contact. In general, men reported more ARSD than women. Men who reported either kissing or having sex the night before reported significantly more ARSD than men not reporting either kissing or having sex. Women who had had sex the night before reported more ARSD than women who had either kissed or not reported any sexual contact on the night before, but women who had kissed did not differ from women who had not had any sexual contact. We suggest that while the DIDS scale of alcohol‐related sexual disinhibition is a valid instrument, gender bias exists. In conclusion, the DIDS does measure the constructs that it sets out to measure. However, significant gender differences do exist and appear to go beyond differences in actual behavior in terms of sexual disinhibition. Men and women describe themselves differently when they describe sexual behavior in general, even when they report similar recent behavior, and we suggest that these differences at least partly reflect sexual stereotypes.
Widening participation and higher education. Students, systems and other paradoxes
Authors: Thompson D.W.
Published: July 2008

This paper has developed from research that the author initiated. The data were derived from an outreach project that aimed to increase awareness of and participation in higher education amongst Muslim women within a major English city. The paper elevates some of the author's findings
into a general discussion on the role of higher education (HE) and the paradoxes that are revealed when considering how concepts of widening participation and lifelong learning fit within the HE system. Readers are invited to think of different approaches to widening participation, for example
through civic and community engagement, and consider sustained research that relates access to wider debates within the study of HE, such as lifelong learning and civic responsibility.
Postgraduate science research skills: the role of creativity, tacit knowledge, thought styles and language
Authors: Marie Jenny
Published: July 2008

This paper analyses three crucial research skills: problem identification, data collection and hypothesis formation. It concludes that science research students should be taught about the creative process as they are under pressures that can inhibit creative thought. They should also
be taught the importance of tacit knowledge for learning how to do research, as this will aid the process. Styles of thought and language allow researchers to identify and solve problems and limit what the latter can be. Students may benefit from further knowledge of these, so they can understand
why their interpretations differ from others and how to create truly original hypotheses. The paper calls for further research into the relationship between language and hypothesis formation.
School evaluation at Japanese schools: policy intentions and practical appropriation
Authors: Katsuno Masaaki , Takei Tetsuro
Published: July 2008

In the present paper the authors will describe the development of school evaluation policies in the context of recent Japanese education reform. In doing so, the applicability of Neave's 'Evaluative State' thesis shall be examined. And then they will move on to the discussion as to
how the policies will work in schools. Drawing on the findings of their empirical research into student involvement in the school evaluation process, the authors will deal with the 'politics of appropriation'. The process could be of a liberating nature at the present time, as opposed to the
managerial intentions of policy.
A keystone effect for parasites in intraguild predation?
Authors: Hatcher Melanie J , Dick Jaimie T.A , Dunn Alison M
Published: July 2008

Intraguild predation (IGP) is common in communities, yet theory suggests it should not often persist and coexistence of participating species should be rare. As parasitism can play keystone roles in interactions between competitors, and between predators and prey, here we examine the role of parasites in maintaining IGP. We used numerical exploration of population dynamic equations to determine coexistence and exclusion zones for two species engaged in IGP with shared parasitism. We demonstrate that parasitism increases the range of conditions leading to coexistence when the parasite exerts a greater deleterious effect on the ‘stronger’ species in terms of the combined effects of competition and predation. Such a parasite can enable an inferior competitor that is also the less predatory to persist, and may actually lead to numerical dominance of this species.
Candidate neural locus for sex differences in reproductive decisions
Authors: Hoke Kim L , Ryan Michael J , Wilczynski Walter
Published: July 2008

Sexual selection and signal detection theories predict that females should be selective in their responses to mating signals in mate choice, while the response of males to signals in male competition should be less selective. The neural processes underlying this behavioural sex difference remain obscure. Differences in behavioural selectivity could result from differences in how sensitive sensory systems are to mating signals, distinct thresholds in motor areas regulating behaviour, or sex differences in selectivity at a gateway relaying sensory information to motor systems. We tested these hypotheses in frogs using the expression of egr-1 to quantify the neural responses of each sex to mating signals. We found that egr-1 expression in a midbrain auditory region was elevated in males in response to both conspecific and heterospecific calls, whereas in females, egr-1 induction occurred only in response to conspecific signals. This differential neural selectivity mirrored the sex differences in behavioural responsiveness to these stimuli. By contrast, egr-1 expression in lower brainstem auditory centres was not different in males and females. Our results support a model in which sex differences in behavioural selectivity arise from sex differences in the neural selectivity in midbrain areas relaying sensory information to the forebrain.
The colour of fossil feathers
Authors: Vinther Jakob , Briggs Derek E.G , Prum Richard O , Saranathan Vinodkumar
Published: July 2008

Feathers are complex integumentary appendages of birds and some other theropod dinosaurs. They are frequently coloured and function in camouflage and display. Previous investigations have concluded that fossil feathers are preserved as carbonized traces composed of feather-degrading bacteria. Here, an investigation of a colour-banded feather from the Lower Cretaceous Crato Formation of Brazil revealed that the dark bands are preserved as elongate, oblate carbonaceous bodies 1–2 μm long, whereas the light bands retain only relief traces on the rock matrix. Energy dispersive X-ray analysis showed that the dark bands preserve a substantial amount of carbon, whereas the light bands show no carbon residue. Comparison of these oblate fossil bodies with the structure of black feathers from a living bird indicates that they are the eumelanin-containing melanosomes. We conclude that most fossil feathers are preserved as melanosomes, and that the distribution of these structures in fossil feathers can preserve the colour pattern in the original feather. The discovery of preserved melanosomes opens up the possibility of interpreting the colour of extinct birds and other dinosaurs.
Biomolecular simulation and modelling: status, progress and prospects
Authors: van der Kamp Marc W , Shaw Katherine E , Woods Christopher J , Mulholland Adrian J
Published: July 2008

Molecular simulation is increasingly demonstrating its practical value in the investigation of biological systems. Computational modelling of biomolecular systems is an exciting and rapidly developing area, which is expanding significantly in scope. A range of simulation methods has been developed that can be applied to study a wide variety of problems in structural biology and at the interfaces between physics, chemistry and biology. Here, we give an overview of methods and some recent developments in atomistic biomolecular simulation. Some recent applications and theoretical developments are highlighted.
Approximate Bayesian computation scheme for parameter inference and model selection in dynamical systems
Authors: Toni Tina , Welch David , Strelkowa Natalja , Ipsen Andreas , Stumpf Michael P.H
Published: July 2008

Approximate Bayesian computation (ABC) methods can be used to evaluate posterior distributions without having to calculate likelihoods. In this paper, we discuss and apply an ABC method based on sequential Monte Carlo (SMC) to estimate parameters of dynamical models. We show that ABC SMC provides information about the inferability of parameters and model sensitivity to changes in parameters, and tends to perform better than other ABC approaches. The algorithm is applied to several well-known biological systems, for which parameters and their credible intervals are inferred. Moreover, we develop ABC SMC as a tool for model selection; given a range of different mathematical descriptions, ABC SMC is able to choose the best model using the standard Bayesian model selection apparatus.
Does a ‘turbophoretic’ effect account for layer concentrations of insects migrating in the stable night-time atmosphere?
Authors: Reynolds A.M , Reynolds D.R , Riley J.R
Published: July 2008

Large migrating insects, such as noctuid moths and acridoid grasshoppers, flying within the stable nocturnal boundary layer commonly become concentrated into horizontal layers. These layers frequently occur near the top of the surface temperature inversion where warm fast-moving airflows provide good conditions for downwind migration. On some occasions, a layer may coincide with a higher altitude temperature maximum such as a subsidence inversion, while on others, it may seem unrelated to any obvious feature in the vertical profile of meteorological variables. Insects within the layers are frequently orientated, either downwind or at an angle to the wind, but the mechanisms involved in both layer formation and common orientation have remained elusive. Here, we show through the results of numerical simulations that if insects are treated as neutrally buoyant particles, they tend to be advected by vertical gusts (through the ‘turbophoretic’ mechanism) into layers in the atmosphere where the turbulent kinetic energy has local minima. These locations typically coincide with local maxima in the wind speed and/or air temperature, and they may also provide cues for orientation. However, the degree of layering predicted by this model is very much weaker than that observed in the field. We have therefore hypothesized that insects behave in a way that amplifies the turbophoretic effect by initiating climbs or descents in response to vertical gusts. New simulations incorporating this behaviour demonstrated the formation of layers that closely mimic field observations, both in the degree of concentration in layers and the rate at which they form.
Hysteresis of soft joints embedded with fluid-filled microchannels
Authors: Ghatak Animangsu , Majumder Abhijit , Kumar Rajendra
Published: July 2008

Many arthropods are known to achieve dynamic stability during rapid locomotion on rough terrains despite the absence of an elaborate nervous system. While muscle viscoelasticity and its inherent friction have been thought to cause this passive absorption of energy, the role of embedded microstructures in muscles and muscle joints has not yet been investigated. Inspired by the soft and flexible hinge joints present in many of these animals, we have carried out displacement-controlled bending of thin elastic slabs embedded with fluid-filled microchannels. During loading, the slab bends uniformly to a critical curvature, beyond which the skin covering the channel buckles with a catastrophic decrease in load. In the reverse cycle, the buckled skin straightens out but at a significantly lower load. In such a loading–unloading cycle, this localized buckling phenomenon results in a dynamic change in the geometry of the joint, which leads to a significant hysteresis in elastic energy. The hysteresis varies nonlinearly with channel diameters and thicknesses of the slab, which is captured by a simple scaling analysis of the phenomenon.
Density-dependent diversification in North American wood warblers
Authors: Rabosky Daniel L , Lovette Irby J
Published: July 2008

Evidence from both molecular phylogenies and the fossil record suggests that rates of species diversification often decline through time during evolutionary radiations. One proposed explanation for this pattern is ecological opportunity, whereby an initial abundance of resources and lack of potential competitors facilitate rapid diversification. This model predicts density-dependent declines in diversification rates, but has not been formally tested in any species-level radiation. Here we develop a new conceptual framework that distinguishes density dependence from alternative processes that also produce temporally declining diversification, and we demonstrate this approach using a new phylogeny of North AmericanDendroicawood warblers. We show that explosive lineage accumulation early in the history of this avian radiation is best explained by a density-dependent diversification process. Our results suggest that the tempo of wood warbler diversification was mediated by ecological interactions among species and that lineage and ecological diversification in this group are coupled, as predicted under the ecological opportunity model.
Bidirectional sex change in mushroom stony corals
Authors: Loya Yossi , Sakai Kazuhiko
Published: July 2008

Sex change occurs when an individual changes from one functional sex to another. The direction of sex change occurs mainly from male to female (protandry) or vice versa (protogyny), but sometimes may be bidirectional (repetitive). Here, for the first time in stony corals, we report on a protandrous sex change exhibited by two mushroom corals,Fungia repandaandCtenactis echinata, with the latter also exhibiting bidirectional sex change. Compared withC. echinata,F. repandaexhibited relatively earlier sex change, significantly slower growth and higher mortality rates, in accordance with sex-allocation theory. Sex ratio in both the species was biased towards the first sex. The bidirectional sex change displayed byC. echinatagreatly resembles that of dioecious plants that display labile sexuality in response to energetic and/or environmental constraints. We posit that, similar to these plants, in the studied corals, sex change increases their overall fitness, reinforcing the important role of reproductive plasticity in scleractinian corals in determining their evolutionary success.
Adaptive numerical competency in a food-hoarding songbird
Authors: Hunt Simon , Low Jason , Burns K.C
Published: July 2008

Most animals can distinguish between small quantities (less than four) innately. Many animals can also distinguish between larger quantities after extensive training. However, the adaptive significance of numerical discriminations in wild animals is almost completely unknown. We conducted a series of experiments to test whether a food-hoarding songbird, the New Zealand robin
Petroica australis
, uses numerical judgements when retrieving and pilfering cached food. Different numbers of mealworms were presented sequentially to wild birds in a pair of artificial cache sites, which were then obscured from view. Robins frequently chose the site containing more prey, and the accuracy of their number discriminations declined linearly with the total number of prey concealed, rising above-chance expectations in trials containing up to 12 prey items. A series of complementary experiments showed that these results could not be explained by time, volume, orientation, order or sensory confounds. Lastly, a violation of expectancy experiment, in which birds were allowed to retrieve a fraction of the prey they were originally offered, showed that birds searched for longer when they expected to retrieve more prey. Overall results indicate that New Zealand robins use a sophisticated numerical sense to retrieve and pilfer stored food, thus providing a critical link in understanding the evolution of numerical competency.