bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sleep‐wakefulness effects after microinjections of hypocretin 1 (orexin A) in cholinoceptive areas of the cat oral pontine tegmentum
Authors: Moreno‐Balandrán Elena , Garzón Miguel , Bódalo Cristina , Reinoso‐Suárez Fernando , De Andrés Isabel 
Published: July 2008

AbstractHypocretinergic/orexinergic neurons, which are known to be implicated in narcolepsy, project to the pontine tegmentum areas involved in the control of rapid eye movement (REM) sleep. Here, we report the effects on sleep‐wakefulness produced by low‐volume microinjections of hypocretin (Hcrt)1 (20–30 nL, 100, 500 and 1000 μm) and carbachol (20–30 nL, 0.1 m) delivered in two areas of the oral pontine tegmentum of free‐moving cats with electrodes for chronic sleep recordings: in the dorsal oral pontine tegmentum (DOPT) and in the ventral part of the oral pontine reticular nucleus (vRPO). Carbachol in the DOPT produced dissociate polygraphic states, with some but not all REM sleep signs. In contrast, carbachol in the vRPO produced a shift with short latency from wakefulness (W) to REM sleep with all of its polygraphic and behavioral signs. Hcrt‐1 in the DOPT increased W and decreased both slow‐wave sleep (SWS) and REM sleep during the first 3 h post‐drug. The same doses of Hcr‐1 in the vRPO produced a significant suppression of REM sleep without a definitive trend for changes in the other states. Both groups showed significant decreases in the number of transitions from SWS to REM sleep. Thus, Hcrt‐1 produced distinct effects in cholinoceptive areas of the oral pontine tegmentum; in the DOPT it promoted W, suppressed SWS and probably defacilitated REM sleep, and in the vRPO it directly inhibited REM sleep. Hypocretinergic/orexinergic signaling is lost in narcoleptics and this absence would mean that pontine defacilitation/inhibition of REM sleep would also be absent, explaining why these patients can fall directly into REM sleep from W.
Rac1 in cortical projection neurons is selectively required for midline crossing of commissural axonal formation
Authors: Kassai Hidetoshi , Terashima Toshio , Fukaya Masahiro , Nakao Kazuki , Sakahara Mizuho , Watanabe Masahiko , Aiba Atsu 
Published: July 2008

AbstractRac1 is a member of Rho family GTPases and regulates multiple cellular functions through actin cytoskeleton reorganization. During cerebral corticogenesis, Rac1 has been assumed to be involved in neuronal migration, neurite formation, polarization and axonal guidance. Here we show the specific role of Rac1, regulating midline crossing of commissural axons during cortical development by using cortex‐restricted Rac1‐knockout mice. In the knockout mice, Rac1 was eliminated from the beginning of corticogenesis exclusively in the dorsal telencephalon where progenitors of cortical projection neurons are located. Cortical lamination was distorted only mildly in the knockout mice, being preserved with six layers of neurons. However, cortex‐restricted Rac1 deletion exhibited striking agenesis of commissural axons including the corpus callosum and anterior commissure without affecting other corticofugal axons including corticospinal and corticothalamic projections. Of note, the commissural axons of the knockout mice were potent in extending their process, but failed to cross the midline. Therefore, these findings indicate that Rac1 specifically controls the midline crossing of the commissural fibers, but not axonal formation of corticospinal or corticothalamic fibers during cortical development.
The top‐down influence of ergogenic placebos on muscle work and fatigue
Authors: Pollo Antonella , Carlino Elisa , Benedetti Fabrizio 
Published: July 2008

AbstractPlacebos have been shown to induce powerful effects in a variety of medical conditions, such as pain and movement disorders, as well as to increase physical performance and endurance in healthy subjects. Here we investigated the effects of an ergogenic placebo on the performance of the quadriceps muscle, which is responsible for the extension of the leg relative to the thigh. In a first experiment, a placebo was administered along with the suggestion that it was caffeine at high dose. This resulted in a significant increase in mean muscle work across subjects, which, however, was not accompanied by a decrease of perceived muscle fatigue. In a second experiment, the placebo caffeine was administered twice in two different sessions. Each time, the weight to be lifted with the quadriceps was reduced surreptitiously so as to make the subjects believe that the ‘ergogenic agent’ was effective. After this conditioning procedure, the load was restored to the original weight, and both muscle work and perceived fatigue assessed after placebo administration. Compared with the first experiment, the placebo effect was larger, with a significant increase in muscle work and decrease in perceived muscle fatigue. Within the context of the role of peripheral and/or central mechanisms in muscle performance, the present findings suggest a central mechanism of top‐down modulation of muscle fatigue. In addition, the difference between the first and second experiment underscores the role of learning in increasing muscle performance with placebos.
It's all relative: ranking the diversity of aquatic bacterial communities
Authors: Shaw Allison K. , Halpern Aaron L. , Beeson Karen , Tran Bao , Venter J. Craig , Martiny Jennifer B. H. 
Published: July 2008

SummaryThe study of microbial diversity patterns is hampered by the enormous diversity of microbial communities and the lack of resources to sample them exhaustively. For many questions about richness and evenness, however, one only needs to know the relative order of diversity among samples rather than total diversity. We used 16S libraries from the Global Ocean Survey to investigate the ability of 10 diversity statistics (including rarefaction, non‐parametric, parametric, curve extrapolation and diversity indices) to assess the relative diversity of six aquatic bacterial communities. Overall, we found that the statistics yielded remarkably similar rankings of the samples for a given sequence similarity cut‐off. This correspondence, despite the different underlying assumptions of the statistics, suggests that diversity statistics are a useful tool for ranking samples of microbial diversity. In addition, sequence similarity cut‐off influenced the diversity ranking of the samples, demonstrating that diversity statistics can also be used to detect differences in phylogenetic structure among microbial communities. Finally, a subsampling analysis suggests that further sequencing from these particular clone libraries would not have substantially changed the richness rankings of the samples.
Colonization of overlaying water by bacteria from dry river sediments
Authors: Fazi Stefano , Amalfitano Stefano , Piccini Claudia , Zoppini Annamaria , Puddu Alberto , Pernthaler Jakob 
Published: July 2008

SummaryWe studied the diversity, community composition and activity of the primary microbial colonizers of the water above freshly re‐wetted sediments from a temporary river. Dried sediments, collected from Mulargia River (Sardinia, Italy), were covered with sterile freshwater in triplicate microcosms, and changes of the planktonic microbial assemblage were monitored over a 48 h period. During the first 9 h bacterial abundance was low (1.5 × 104 cells ml−1); it increased to 3.4 × 106 cells ml−1 after 28 h and did not change thereafter. Approximately 20% of bacteria exhibited DNA de novo synthesis already after 9 h of incubation. Changes of the ratios of 3H‐leucine to 3H‐thymidine incorporation rates indicated a shift of growth patterns during the experiment. Extracellular enzyme activity showed a maximum at 48 h with aminopeptidase activity (430.8 ± 22.6 nmol MCA l−1 h−1) significantly higher than alkaline phosphatase (98.6 ± 4.3 nmol MUF l−1 h−1). The primary microbial colonizers of the overlaying water – as determined by 16S rRNA gene sequence analysis – were related to at least six different phylogenetic lineages of Bacilli and to Alphaproteobacteria (Brevundimonas spp. and Caulobacter spp.). Large bacterial cells affiliated to one clade of Bacillus sp. were rare in the dried sediments, but constituted the majority of the planktonic microbial assemblage and of cells with detectable DNA‐synthesis until 28 h after re‐wetting. Their community contribution decreased in parallel with a rise of flagellated and ciliated protists. Estimates based on cell production rates suggested that the rapidly enriched Bacillus sp. suffered disproportionally high loss rates from selective predation, thus favouring the establishment of a more heterogenic assemblage of microbes (consisting of Proteobacteria, Actinobacteria and Cytophaga‐Flavobacteria). Our results suggest that the primary microbial colonizers of the water above dried sediments are passively released into the plankton and that their high growth potential is counteracted by the activity of bacterivorous protists.
Variations in the mosquito larvicidal activities of toxins from Bacillus thuringiensis ssp. israelensis
Authors: Otieno‐Ayayo Zachariah Ngalo , Zaritsky Arieh , Wirth Margaret C. , Manasherob Robert , Khasdan Vadim , Cahan Rivka , Ben‐Dov Eitan 
Published: July 2008

SummaryComparing activities of purified toxins from Bacillus thuringiensis ssp. israelensis against larvae of seven mosquito species (vectors of tropical diseases) that belong to three genera, gleaned from the literature, disclosed highly significant variations in the levels of LC50 as well as in the hierarchy of susceptibilities. Similar toxicity comparisons were performed between nine transgenic Gram‐negative species, four of which are cyanobacterial, expressing various combinations of cry genes, cyt1Aa and p20, against larvae of four mosquito species as potential agents for biological control. Reasons for inconsistencies are listed and discussed. Standard conditions for toxin isolation and presentation to larvae are sought. A set of lyophilized powders prepared identically from six Escherichia coli clones expressing combinations of four genes displayed toxicities against larvae of three mosquito species, with levels that differed between them but with identical hierarchy.
Injectable silicone biomaterial (PTQTM) is more effective than carbon‐coated beads (Durasphere®) in treating passive faecal incontinence – a randomized trial
Authors: Tjandra J. J. , Chan M. K. Y. , Yeh H. C. H. 
Published: July 2008

AbstractObjective  Both injectable silicone biomaterial (PTQTM) and pyrolytic carbon‐coated beads (Durasphere®) have been shown to be effective in treating passive faecal incontinence due to internal sphincter dysfunction. This is a randomized study to evaluate their relative safety and efficacy.Method  Forty patients (mean age 59.5 years vs 58.9 years) were randomized to have inter‐sphincteric injection of PTQTM or submucosal injection of Durasphere®. Patients were assessed with anorectal physiology, endoanal ultrasound, a validated incontinence score and quality of life questionnaires.Results  In the Durasphere® group, complications included rectal pain (5%), erosion through rectal mucosa (10%), and type III hypersensitivity reaction (5%). No complications occurred in the PTQTM group. Compared with PTQTM, Durasphere® group has a more rapid action, with improved continence at 2 weeks after injection. In both groups, faecal continence significantly improved 6 weeks after injection, and continued to improve significantly up to 6 months in both groups (P < 0.0001). At 6 weeks, 6 and 12 months after injection, significantly more PTQTM patients achieved greater than 50% improvement in Wexner’s continence score than Durasphere® patients (respectively, P = 0.01; P < 0.0001; P = 0.001). There was a significant improvement in faecal incontinence quality of life scale and the 12‐month physical health scale of Short Form‐12 health survey in the PTQTM group but not in the Durasphere® group.Conclusion  In patients with internal sphincter dysfunction, injectable silicone biomaterial was safer and more effective than Durasphere®.
Cutaneous bioengineering instrumentation standardization: the Tissue Viability Imager
Authors: Nilsson Gert E. , Zhai Hongbo , Chan Heidi P. , Farahmand Sara , Maibach Howard I. 
Published: July 2008

Background: Tissue Viability Imaging (TiVi) is a new bioengineering technology intended for remote two‐dimensional mapping of skin red blood cell concentration (RBCconc). Before use in the laboratory, work‐site and dermatology clinic, critical performance parameters of this emerging technology require careful evaluation.Objective: To assess short‐ and long‐term stability, image uniformity, distance and image size dependence, ambient light and curvature influence in a production batch of Tissue Viability Imagers.Methods: Four Tissue Viability Imagers from the same production batch were evaluated at two laboratories (one industrial and one dermatological) with respect to critical parameter performance.Results: The average systematic drift in sensitivity over time was 0.27% and <1.02% for all four units tested. Difference in sensitivity between units was limited to 4.1% and was due to offset rather than gain deviation. Spatial variation in image uniformity was below 3.08% and 1.93% in the corners and centre of an individual image, respectively. This spatial variation could be further reduced to 0.25% and 0.13%, respectively by image normalization. Ambient light from a 40 W bulb or a 11 W fluorescent light source at a distance of 50–60 cm above the object, reduced the recorded values by about 10%, while the camera to object distance and image size had no detectable influence on sensitivity. Curved objects, such as human forearm, demonstrated an edge effect limited to below 10%.Conclusion: The critical TiVi performance parameters evaluated proved stable in relation to expected variations in skin RBCconc over time. Calibration by way of a two‐point method may reduce differences in sensitivity between instruments to further facilitate inter‐laboratory comparison of results.
Comparative Analysis of JmjC Domain‐containing Proteins Reveals the Potential Histone Demethylases in Arabidopsis and Rice
Authors: Lu Falong , Li Guanglin , Cui Xia , Liu Chunyan , Wang Xiu‐Jie , Cao Xiaofeng 
Published: July 2008

Abstract Histone methylation homeostasis is achieved by controlling the balance between methylation and demethylation to maintain chromatin function and developmental regulation. In animals, a conserved Jumonji C (JmjC) domain was found in a large group of histone demethylases. However, it is still unclear whether plants also contain the JmjC domain‐containing active histone demethylases. Here we performed genome‐wide screen and phylogenetic analysis of JmjC domain‐containing proteins in the dicot plant, Arabidopsis, and monocot plant rice, and found 21 and 20 JmjC domain‐containing, respectively. We also examined the expression of JmjC domain‐containing proteins and compared them to human JmjC counterparts for potential enzymatic activity. The spatial expression patterns of the Arabidopsis JmjC domain‐containing genes revealed that they are all actively transcribed genes. These active plant JmjC domain‐containing genes could possibly function in epigenetic regulation to antagonize the activity of the large number of putative SET domain‐containing histone methyltransferase activity to dynamically regulate histone methylation homeostasis.
Subcellular Localizations of AS1 and AS2 Suggest Their Common and Distinct Roles in Plant Development
Authors: Zhu Yan , Li Ziyu , Xu Ben , Li Hongda , Wang Lingjian , Dong Aiwu , Huang Hai 
Published: July 2008

Abstract During leaf organogenesis, a critical step for normal leaf primordium initiation is the repression of the class 1 KNOTTED1‐like homeobox (KNOX) genes. After leaf primordia are formed, they must establish polarity for normal leaf morphogenesis. Recent studies have led to the identification of a number of genes that participate in the class 1 KNOX gene repression and/or the leaf polarity establishment. ASTMMETRIC LEAVES1 and 2 (AS1 and AS2) are two of these genes, which are critical for both of these two processes. As a first step towards understanding the molecular genetic basis of the AS1–AS2 action, we determined the subcellular localizations of the two proteins in both tobacco BY2 cells and Arabidopsis plants, by fusing them to yellow/cyan fluorescent protein (YFP/CFP). Our data showed that AS1 and AS2 alone were predominantly localized in the nucleolus and the nucleoplasm, respectively. The presence of both AS1 and AS2 proteins in the same interphase cell demonstrated their co‐localization in both nucleolus and nucleoplasm. In addition, AS1 alone was able to associate with the condensed chromosome in the metaphase cell. Our data suggest that AS1, AS2 and the AS1‐AS2 protein complex may have distinct functions, which are all required for normal plant development.
Gamete Recognition in Higher Plants: An Abstruse but Charming Mystery
Authors: Peng Xiong‐Bo , Sun Meng‐Xiang 
Published: July 2008

Abstract Although much effort has been made to uncover the mechanism underlying double fertilization, little knowledge has been acquired for understanding the molecular base of gamete recognition, mainly because of technical limitations. Still, progress has been made in terms of the mechanism, including the identification of candidate molecules that are involved in gamete recognition in angiosperms. New cues for gamete recognition have been found by the successful separation of the gametes and construction of gamete‐specific cDNA libraries in several species, and the application of molecular approaches for studying this process by mutations. Thus, the topic is considered an abstruse but charming mystery.
Membrane Transporters for Nitrogen, Phosphate and Potassium Uptake in Plants
Authors: Chen Yi‐Fang , Wang Yi , Wu Wei‐Hua 
Published: July 2008

Abstract Nitrogen, phosphorous and potassium are essential nutrients for plant growth and development. However, their contents in soils are limited so that crop production needs to invest a lot for fertilizer supply. To explore the genetic potentialities of crops (or plants) for their nutrient utilization efficiency has been an important research task for many years. In fact, a number of evidences have revealed that plants, during their evolution, have developed many morphological, physiological, biochemical and molecular adaptation mechanisms for acquiring nitrate, phosphate and potassium under stress conditions. Recent discoveries of many transporters and channels for nitrate, phosphate and potassium uptake have opened up opportunities to study the molecular regulatory mechanisms for acquisition of these nutrients. This review aims to briefly discuss the genes and gene families for these transporters and channels. In addition, the functions and regulation of some important transporters and channels are particularly emphasized.
Rising jet-inflated bubbles in clusters of galaxies
Authors: Sternberg Assaf , Soker Noam 
Published: July 2008

Abstract
We conduct two-dimensional axisymmetric (referred to as 2.5D) hydrodynamical numerical simulations of bubble evolution in clusters of galaxies. We inflate bubbles using slow, massive jets with a wide opening angle, and follow their evolution as they rise through the intracluster medium. We find that these jet-inflated bubbles are quite stable, and can reach large distances in the cluster while maintaining their basic structure. The stability of the jet-inflated bubble comes mainly from the dense shell that forms around it during its inflation stage, and from the outward momentum of the bubble and shell. On the contrary, bubbles that are inserted by hand on to the grid and not inflated by a jet, i.e. an artificial bubble, lack these stabilizing factors; therefore, they are rapidly destroyed. The stability of the jet-inflated bubble removes the demand for stabilizing magnetic fields in the bubble.
Lifetimes of tidally limited star clusters with different radii
Authors: Gieles M. , Baumgardt H. 
Published: July 2008

Abstract
We study the escape rate of stars, , from clusters with different radii on circular orbits in a tidal field using analytical predictions and direct N-body simulations. We find that depends on the ratio , where rh is the half-mass radius and rJ the radius of the zero-velocity surface around the cluster. For , the ‘tidal regime’, there is almost no dependence of on . To first order this is because the fraction of escapers per half-mass relaxation time, trh, scales approximately as , which cancels out the r3/2h term in trh. For , the ‘isolated regime’, scales as . The dissolution time-scale, tdis, falls in three regimes. Clusters that start with their initial , in the tidal regime dissolve completely in this regime and their tdis is, therefore, insensitive to the initial rh. Our model predicts that has to be 10−20–10−10 for clusters to dissolve completely in the isolated regime. This means that realistic clusters that start with always expand to the tidal regime before final dissolution. Their tdis has a shallower dependence on than what would be expected when tdis is a constant times trh. For realistic values of , the lifetime varies by less than a factor of 1.5 due to changes in . This implies that the ‘survival’ or ‘vital’ diagram for globular clusters should allow for more small clusters to survive. We note that with our result it is impossible to explain the universal peaked mass function of globular cluster systems by dynamical evolution from a power-law initial mass function, since the peak will be at lower masses in the outer parts of galaxies. Our results finally show that in the tidal regime tdis scales as N0.65/ω, with ω the angular frequency of the cluster in the host galaxy.
Liquidity, the Value of the Firm, and Corporate Finance
Authors: Amihud Yakov , Mendelson Haim 
Published: July 2008

The theory of corporate finance has been based on the idea that a company's market value is determined mainly by just two variables: the company's expected after‐tax operating cash flows or earnings, and the risk associated with producing them. The authors argue that there is another important factor affecting a company's value: the liquidity of its own securities, debt as well as equity. The paper supports this argument by reviewing the large and growing body of evidence showing that differences—and changes—in liquidity can have major effects on the pricing of corporate stocks and bonds or, equivalently, on investors' required returns for holding them.The authors also suggest that the liquidity of a company's securities can be managed by corporate policies and actions. For those companies whose value is likely to be increased by having more liquid securities—which is by no means true of all companies (mature firms that don't need outside capital may well benefit from having more concentrated ownership and hence less liquidity)—management should consider actions such as reducing leverage and substituting dividends for stock repurchases as well as measures designed to increase the effectiveness of their disclosure and investor relations program and the size of their investor base.