bluuebunny/crossref_metadata_2025 huggingface dataset:
Holcus mollis L. subsp. hierrensis (Poaceae), a new subspecies of El Hierro (Canary Islands), and some notes on the species
Authors: Stierstorfer Ch.
Published: August 2010

Holcus mollis L. subsp. hierrensis is new to science. Its distinct chamaephytic habit and particular features of the morphology of the spikelets, provided in a key, as well as its ecology allow a taxonomic separation from the otherwise similar subsp. mollis. A short survey of important facts about the species given in the literature is presented. The possible status of the new subspecies as a neoendemic of the island of El Hierro (Canaries) is discussed.
The individual variation in carotenoid content of the lichen species Dirinaria applanata (Fée) Awasthi
Authors: Czeczuga B. , Czeczuga‐Semeniuk E. , Aptroot A.
Published: August 2010

Column and thin‐layer chromatography revealed the presence of the following carotenoids in thalli of Dirinaria applanata from 13 different sites: α‐carotene, β‐carotene, β‐cryptoxanthin, lutein, 3′‐epilutein, zeaxanthin, antheraxanthin, canthaxanthin, astaxanthin, violaxanthin, mutatoxanthin, neoxanthin, capsochrome, fucoxanthinol, paracentrone and apo‐6′‐lycopenal. In the thalli of all 13 specimens of Dirinaria applanata β‐carotene, lutein, astaxanthin and violaxanthin were found as constant carotenoids.

The total content of carotenoids ranged from 21.0 (from Mexico) to 54.9 μg g−1 dry weight (from Antilles).
Achievements and perspectives of top‐down proteomics
Authors: Armirotti Andrea , Damonte Gianluca
Published: August 2010

Over the last years, top‐down (TD) MS has gained a remarkable space in proteomics, rapidly trespassing the limit between a promising approach and a solid, established technique. Several research groups worldwide have implemented TD analysis in their routine work on proteomics, deriving structural information on proteins with the level of accuracy that is impossible to achieve with classical bottom‐up approaches. Complete maps of PTMs and assessment of single aminoacid polymorphisms are only a few of the results that can be obtained with this technique. Despite some existing technical and economical limitations, TD analysis is at present the most powerful instrument for MS‐based proteomics and its implementation in routine workflow is a rapidly approaching turning point in proteomics. In this review article, the state‐of‐the‐art of TD approach is described along with its major advantages and drawbacks and the most recent trends in TD analysis are discussed. References for all the covered topics are reported in the text, with the aim to support both newcomers and mass spectrometrists already introduced to TD proteomics.
Developing biodiversity indicators for cities: applying the DPSIR model to Nagoya and integrating social and ecological aspects
Authors: Kohsaka Ryo
Published: August 2010

Capturing the trends and status of urban biodiversity is challenged by current rapid changes, including increasing population flow into urban areas and multiple pressures on neighboring ecosystems. For this reason, this article aims to highlight relevant findings from both ecological and social sciences in the development of urban and biodiversity indicators. It examines the applicability of a model to an urban city in Japan. The objectives of this study are threefold. First, it reviews and summarizes the historical development and relevant existing studies of urban and biodiversity indicators, the “Drivers‐Pressure‐State‐Impact‐Response” (DPSIR) model is presented, and its main critiques are summarized. Second, trends in scientific studies in specific journals are identified. Third, practical lessons for a Japanese local municipality, the city of Nagoya, are derived from two previous sets of reviews. The applicability of the “DPSIR” to current practices in the city of Nagoya is examined to assess the relevance of the model to real situations.
Mountain biodiversity conservation and management: a paradigm shift in policies and practices in the Hindu Kush‐Himalayas
Authors: Sharma Eklabya , Chettri Nakul , Oli Krishna Prasad
Published: August 2010

Mountains occupy 24% of the global land surface area and are home to 12% of the world's population. They have ecological, aesthetic, and socioeconomic significance, not only for people living in mountain areas, but for those living beyond. Mountains need specific attention for their contribution to global goods and services, especially by developing and implementing mountain specific policies. Conservation policies have evolved from the protection of charismatic species, to habitat and ecosystem/landscape conservation, and, finally, to people‐oriented conservation approaches. This paper, with particular reference to paradigm shifts in the Hindu Kush‐Himalayan (HKH) region, discusses the evolution of conservation policies, developments in conservation practices, the status of protected area management, wetland conservation initiatives and the landscape approach, community‐based conservation initiatives, and the convergence of policies and practices. In the HKH region, conservation efforts now adopt participatory approaches, implement policies of decentralised governance for biodiversity management, and empower local communities in biodiversity management. The paradigm shift in the policies and practices related to conservation has been gradual and has included the acceptance of communities as an integral part of national level conservation initiatives, together with the integration of many global conventions. There are many successful pilots in the HKH region that deserve upscaling by the countries from the region. Realising the importance of mountains as hotspots of biodiversity, and due to their role as providers of global goods and services, the Convention on Biological Diversity adopted the Programme of Work on Mountain Biodiversity. Such a decision specific to mountains provides enormous opportunities for both conservation and development. Recent challenges posed by climate change need to be integrated into overall biodiversity conservation and management agendas, especially in mountain areas. The HKH region has been identified as a blank spot for data by the Inter‐Governmental Panel on Climate Change, indicating the need to develop regional database and sharing mechanisms. This is a tall task, but one that holds enormous opportunity for the HKH countries and institutions with regional mandates to address the emerging challenges of climate change on biodiversity conservation by reducing scientific uncertainty.
Drug disposition in obesity and protein–energy malnutrition
Authors: Boullata Joseph I.
Published: August 2010

Clinical response to medication can differ between patients. Among the known sources of variability is an individual's nutrition status. This review defines some pharmacokinetic terms, provides relevant body size metrics and describes the physiologic influences of protein–energy malnutrition and obesity on drug disposition. Weight-based drug dosing, which presumes a healthy BMI, can be problematic in the protein–energy malnourished or obese patient. The use of total body weight, lean body weight, or an adjusted body weight depends on the drug and how it is differently handled in malnutrition or obesity. Most of the recognized influences are seen in drug distribution and drug elimination as a result of altered body composition and function. Distribution characteristics of each drug are determined by several drug-related factors (e.g. tissue affinity) in combination with body-related factors (e.g. composition). Drug elimination occurs through metabolic and excretory pathways that can also vary with body composition. The current data are limited to select drugs that have been reported in small studies or case reports. In the meantime, a rational approach to evaluate the potential influences of malnutrition and obesity can be used clinically based on available information. Antimicrobials are discussed as a useful example of this approach. Further advancement in this field would require collaboration between experts in body composition and those in drug disposition. Until more data are available, routine monitoring by the clinician of the protein–energy malnourished or obese patient receiving weight-based drug regimens is necessary.
Metabolic and hormonal aspects of polycystic ovary syndrome: the impact of diet
Authors: O'Connor Annalouise , Gibney James , Roche Helen M.
Published: August 2010

Polycystic ovary syndrome (PCOS) is a common, chronic endocrine condition affecting young women of reproductive age. It is characterised by hyperandrogenaemia, and profound menstrual and ovulatory dysfunction with consequent sub-fertility. A clustering of metabolic aberrations is commonly associated with this condition and these include insulin resistance, disordered lipid metabolism and chronic low-grade inflammation. Overweight and obesity, as well as a degree of adipose tissue dysfunction, are present in a large proportion of women with PCOS, and where present, magnify the inherent hyperandrogenaemia characteristic of the condition, in addition to worsening the metabolic profile. Diet and lifestyle interventions are among the first-line treatments for PCOS, and weight reduction through energy restriction has been shown to exert positive influences on both metabolic and hormonal aspects of this condition. Alterations in carbohydrate amount and type have also been investigated, and more recently, dietary fatty acids, with a particular emphasis on PUFA, have been shown to have a positive impact within this population group. Although it is likely that diet is not the root cause of PCOS, it represents a modifiable variable with the potential to improve the health of women with this condition. Work to date has provided insights into the role of diet in PCOS; however, further work is required to determine the role of nutrients specifically within the context of PCOS, in order to develop more effective, evidence-based dietary guidelines for this condition.
Density-dependent effects on parasite growth and parasite-induced host immunodepression in the larval helminthPomphorhynchus laevis
Authors: CORNET STEPHANE
Published: August 2010

Larval helminths exploit the physiology of their intermediate hosts: first, as a resource for energy and space and second by altering the immune system activity to ensure their survival. Whereas the growth pattern under parasite competition has been investigated, the effect of multiple infections on the level of parasite-induced immunodepression in a trophically transmitted helminth has been neglected. In this study, amphipodsGammarus pulexwere infected in the laboratory by the acanthocephalanPomphorhynchus laevisto investigate how parasite density in the intermediate host affected (i) cystacanth growth and (ii) the level of parasite-induced alterations of the host immune defences, two traits strongly linked to host exploitation. The study highlights that sharing a host is costly. As parasite intensity increases, competition for resources translates into a reduction in cystacanth volume. Immune manipulation is also modulated by density. Interestingly, immunodepression is higher in double-infected hosts compared to hosts with a single infection, suggesting an opportunity for cooperative immune manipulation. However, in higher multiple infections, parasites do not further down-regulate the host immune response, possibly to avoid additional costs that may outweigh the benefits of immunodepression.
High-throughput screening in suboptimal growth conditions identifies agonists ofGiardia lambliaproliferation
Authors: FAGHIRI Z. , SANTIAGO R. BONILLA , WU Z. , WIDMER G.
Published: August 2010

Giardia lambliais one of the most prevalent parasites of mankind and is estimated to cause over 200 million infections per year. To screen chemical libraries for compounds that perturb trophozoite proliferation we adapted a conventional culture method to 384-well plates and identified numerous inhibitors. Here we used a modified assay to screen for compounds that promote trophozoite multiplication. Trophozoite growth was reduced by dilution of the culture medium and the growth period was extended to screen 2 compound libraries comprising 1500 compounds. A total of 4 agonists of trophozoite multiplication were identified. In the presence of one of these compounds, strychnine, enhanced growth was accompanied by unusual trophozoite morphology characterized by dividing trophozoites displaying more than the 2 nuclei per cell which are normally observed. The other agonists, although belonging to 2 distinct chemical groups, are known to affect isoprenylation, indicating a link between protein or lipid isoprenylation and growth in culture. Although inhibitors of isoprenylation are known to antagonize proliferation of mammalian cells, an agonistic effect of isoprenylation modulators has to our knowledge not been described previously. These observations illustrate the power of chemical genetics for identifying pathways controlling specific traits inG. lamblia.
More Democracy: The Direct Primary and Competition in U.S. Elections
Authors: Ansolabehere Stephen , Hansen John Mark , Hirano Shigeo , Snyder James M.
Published: August 2010

This article offers a first-ever comprehensive empirical assessment of a key Progressive reform, the direct primary, and its impact on competition in American elections. We begin with a review of the problems Progressives diagnosed in the American electoral system and reasons to expect the direct primary to be a pro-competitive, democratizing reform. We then consider prior research into the direct primary and electoral contestation and describe the database of primary and general election outcomes that we have constructed to trace competition in primaries for federal and statewide offices. Finally, we examine the historical trajectory of competition in primary elections, starting with the first decades after the introduction of the reform and then the succeeding decades.

Consistent with the hopes of reformers, we find primary elections indeed provided a forum for contestation for federal and statewide elections. Although primaries were never broadly competitive, even at the outset, they accounted for about a third of the serious electoral tests faced by statewide officeholders and about a fifth faced by U.S. representatives. The role of primaries as a venue for robust contestation, however, was short-lived, as the competitiveness of federal and statewide primaries decreased sharply starting in the 1940s. The last section of this article explores whether two recent developments in American elections—the extension of two-party competition and the rise in the value of incumbency—conspired to temper the contribution of direct primaries to electoral competition.
Research on financial and monetary history based on the records of the Bank of Japan Archives: a note
Authors: Ohnuki Mari , Murakami Daisuke , Takashima Masanori
Published: August 2010

This brief survey gives an overview of the research on Japanese financial and monetary history based on the records of the Bank of Japan Archives. We briefly describe the Bank of Japan's organizational history, the activities of the Archives, their history and the classification of documents preserved in the Archives. We finally survey the recent research in Japanese economic history from the viewpoint of materials in the Archives.
Hydrate dissolution as a potential mechanism for pockmark formation in the Niger delta
Authors: Sultan N. , Marsset B. , Ker S. , Marsset T. , Voisset M. , Vernant A. M. , Bayon G. , Cauquil E. , Adamy J. , Colliat J. L. , Drapeau D.
Published: August 2010

Based on acquired geophysical, geological and geotechnical data and modeling, we suggest hydrate dissolution to cause sediment collapse and pockmark formation in the Niger delta. Very high‐resolution bathymetry data acquired from the Niger delta reveal the morphology of pockmarks with different shapes and sizes going from a small ring depression surrounding an irregular floor to more typical pockmarks with uniform depression. Geophysical data, in situ piezocone measurements, piezometer measurements and sediment cores demonstrate the presence of a common internal architecture of the studied pockmarks: inner sediments rich in gas hydrates surrounded by overpressured sediments. The temperature, pressure and salinity conditions of the studied area have allowed us to exclude the process of gas‐hydrate dissociation (gas hydrate turns into free gas/water mixture) as a trigger of the observed pockmarks. Based on numerical modeling, we demonstrate that gas‐hydrate dissolution (gas hydrate becomes mixture of water and dissolved gas) under a local decrease of the gas concentration at the base of the gas‐hydrate occurrence zone (GHOZ) can explain the excess pore pressure and fluid flow surrounding the central hydrated area and the sediment collapse at the border of the GHOZ. The different deformation (or development) stages of the detected pockmarks confirm that a local process such as the amount of gas flow through faults rather than a regional one is at the origin of those depressions.
Distinct roles in NKT cell maturation and function for the different transcription factors in the classical NF‐κB pathway
Authors: Stankovic Sanda , Gugasyan Raffi , Kyparissoudis Konstantinos , Grumont Raelene , Banerjee Ashish , Tsichlis Philip , Gerondakis Steve , Godfrey Dale I
Published: August 2010

The nuclear factor (NF)‐κB signalling pathway is known to be critical for natural killer T (NKT) cell differentiation; however, the role of individual NF‐κB transcription factors and the precise developmental stages that they control remain unclear. We have investigated the influence of the classical NF‐κB transcription factors NF‐κB1, c‐Rel and RelA on NKT cell development and function, using gene‐deleted mice. Individually, none of these factors were essential for the requirement of NF‐κB signalling in early NKT cell development before NK1.1 expression, in contrast to earlier reports in which the classical NF‐κB pathway was globally disrupted. Instead, we found that each factor played a non‐redundant role in later stages of NKT cell maturation and function. Although NF‐κB1 deficiency resulted in a moderate reduction in mature NK1.1+ NKT cells, this was found to be more subtle than previously reported. RelA deficiency had a more profound effect on the NK1.1+ stage of NKT cell development, whereas c‐Rel‐deficient mice had normal NKT cell numbers. All three factors (NF‐κB1, RelA and c‐Rel) were necessary for normal NKT cell cytokine production. Notably, IL‐17, which is produced by a specific subset of NKT cells (NKT‐17 cells), defined as NK1.1−CD4−, was not impaired by a lack of these individual NF‐κB transcription factors, nor was this subset depleted, suggesting that NKT‐17 cells are regulated independently of the NF‐κB pathway. Thus, individual NF‐κB family members have a largely redundant role in early NKT cell development, but each of them has an important and distinct role in NKT cell maturation and/or function.
CD40 engagement on dendritic cells induces cyclooxygenase‐2 and EP2 receptor via p38 and ERK MAPKs
Authors: Harizi Hedi , Limem Ilef , Gualde Norbert
Published: August 2010

We have previously reported that cyclooxygenase (COX)‐2‐derived prostaglandin (PG)E2 critically regulates dendritic cell (DC) inflammatory phenotype and function through EP2/EP4 receptor subtypes. As genes activated by CD40 engagement are directly relevant to inflammation, we examined the effects of CD40 activation on inflammatory PGs in murine bone marrow‐derived DC (mBM‐DC). We showed for the first time that activation of mBM‐DC with agonist anti‐CD40 monoclonal antibody (anti‐CD40 mAb) dose dependently induces the synthesis of significant amounts of PGE2 via inducible expression of COX‐2 enzyme, as NS‐398, a COX‐2‐selective inhibitor reduces this upregulation. In contrast to lipopolysaccharide, which upregulates mBM‐DC surface levels of EP2 and EP4 receptors, CD40 crosslinking on mBM‐DC increases EP2, but not EP4, receptor expression. Flow cytometry analysis and radioligand‐binding assay showed that EP2 was the major EP receptor subtype, which binds to PGE2 at the surface of anti‐CD40‐activated mBM‐DC. Upregulation of COX‐2 and EP2 levels by CD40 engagement was accompanied by dose‐dependent phosphorylation of p38 and ERK1/2 mitogen‐activated protein kinase (MAPK) and was abrogated by inhibitors of both pathways. Collectively, we demonstrated that CD40 engagement on mBM‐DC upregulates COX‐2 and EP2 receptor expression through activation of p38 and ERK1/2 MAPK signaling. Triggering the PGE2/EP2 pathway by anti‐CD40 mAb resulted on the induction of Th2 immune response. Thus, CD40‐induced production of PGE2 by mBM‐DC could represent a negative feedback mechanism involving EP2 receptor and limiting the propagation of Th1 responses. Blocking CD40 pathway may represent a novel therapeutic pathway of inhibiting COX‐2‐derived prostanoids in chronically inflamed tissues (that is, arthritis).
Electrical properties of rectifying contacts on selectively carrier controlled grown ZnO thin films
Authors: Bhattacharya A. , Gupta R. K. , Kahol P. K. , Ghosh K.
Published: August 2010

Controlled decrease in carrier concentration (Nd) through postdeposition annealing of ZnO is shown to provide a crossover from Ohmic to rectifying junction behavior. Highly oriented (002) ZnO films with silver contact yield nonlinear I-V characteristics below a carrier concentration of ∼1023 m−3 and linear Ohmic behavior above 1023 m−3. The specific differential resistance around zero bias is practically independent of carrier concentration up to 1023 m−3 and then decreases with increase in carrier concentration. These results are in excellent agreement with standard theoretical models of current transport phenomena in metal–semiconductor contacts. While the differential junction resistance at lower carrier concentrations gradually becomes less governed by carrier concentrations and current transport is dominated by thermionic emission and diffusion mechanism, it decreases as a function of carrier concentration at higher carrier concentrations. These results show that metal–oxide semiconductor junctions behave precisely like conventional metal–semiconductor junctions.
Transverse resonant properties of strained gold nanowires
Authors: Olsson Pär A. T.
Published: August 2010

In this work, resonant and elastic properties of single crystal gold nanowires have been studied through classical molecular dynamics simulations. The considered nanowires have perfect square cross sections and are oriented with the [100] direction along the wire axis and with {100} side surfaces. Three different sizes were simulated; 4.08×4.08 nm2, 5.71×5.71 nm2, and 7.34×7.34 nm2 cross sectional dimensions, with the respective unrelaxed lengths 49.0 nm, 68.5 nm, and 88.1 nm and the simulations were performed at two different temperatures, 4.2 K and 300 K. Tensile simulations reveal, that the stiffness decreases with decreasing size, and that the size dependence for nanowires at 4.2 K can be accurately described using the concept of surface energy. Comparing results from the resonant simulations reveals that the fundamental eigenfrequency is in good agreement with predictions from Bernoulli–Euler continuum beam theory when the size dependence of the stiffness is taken into account. The eigenfrequencies of the first and second excited modes turn out to be low in comparison with analytical Bernoulli–Euler continuum calculations.
Polycrystalline diamond based detector for Z-pinch plasma diagnosis
Authors: Liu Linyue , Ouyang Xiaoping , Zhao Jizhen , Chen Liang , Wang Lan
Published: August 2010

A detector setup based on polycrystalline chemical-vapor-deposition diamond film is developed with great characteristics: low dark current (lower than 60 pA within 3 V/μm), fast pulsed response time (rise time: 2–3 ns), flat spectral response (3–5 keV), easy acquisition, low cost, and relative large sensitive area. The characterizing data on Qiangguang-I accelerator show that this detector can satisfy the practical requirements in Z-pinch plasma diagnosis very well, which offers a promising prototype for the x-ray detection in Z-pinch diagnosis.
Temporal field emission current stability and fluctuations from graphene films
Authors: Uppireddi Kishore , Rao Chitturi Venkateswara , Ishikawa Yasuyuki , Weiner Brad R. , Morell Gerardo
Published: August 2010

Stable field emission currents and low fluctuations are important feasibility requirements for the application of materials in field emission devices and displays. The current stability and current fluctuations of field emitted electrons from graphene films are investigated for the periods of 24 and 100 h. The graphene films showed different percentage of variation from the initial current density for different films ranging from 6% to 46% and the standard deviation in the range of 2–6 μA/cm2. The short- and long-term stability and fluctuations of the graphene films are reported and the causes for degradation of the emission current are discussed.
Identifying configuration and orientation of adsorbed molecules by inelastic electron tunneling spectra
Authors: Ren Hao , Yang Jinlong , Luo Yi
Published: August 2010

Scanning tunneling microscopy (STM) topographical images and inelastic electron tunneling spectra (IETS) of a cis-2-butene molecule adsorbed on a Pd(110) surface have been simulated by first-principles calculations. Calculations have eliminated the ambiguity between the STM image and the adsorption orientation caused by the symmetry of the system and local chemical environment. A combination of STM images and IETS spectra has been shown to be particularly useful in determining the configuration of the molecule on the surface.
Charge trapping in hybrid electroluminescence device containing CdSe/ZnS quantum dots embedded in a conducting poly(N-vinylcarbozole) layer
Authors: Li Fushan , Guo Tailiang , Kim Taewhan
Published: August 2010

Charge transport in a multilayer hybrid electroluminescence (EL) device containing CdSe/ZnS quantum dots (QDs) embedded in hole-transporting poly(N-vinylcarbozole) (PVK) layer was investigated. The current-voltage (I-V) curve exhibited resistive transition at low bias voltage and a negative differential resistance region with increase in bias voltage, which can be explained in terms of a two-step charge transport process, i.e., holes trapping and the following hole-electron recombination in CdSe/ZnS QDs embedded in PVK layer. EL spectra showed that the recombination center would be restricted to CdSe/ZnS QDs at high bias voltage, which is in well agreement with the I-V results.
A Facile and Divergent Synthesis of Substituted Pyridine-2,4(1H,3H)-diones and 4H-Thiopyran-4-ones from α-Alkenoyl-α-carbamoyl Ketene-S,S-acetals
Authors: Liu Jinying , Fu Xiaolan , Zhou Yang , Zhou Guangyuan , Liang Yongjiu , Dong Dewen
Published: August 2010

A facile and divergent synthesis of substituted pyridine-2,4(1H,3H)-diones and 4H-thiopyran-4-ones from readily available α-alkenoyl-α-carbamoyl ketene-S,S-acetals has been developed. Subjected to N,N-dimethylformamide at 125°C, α-alkenoyl-α-carbamoyl ketene-S,S-acetals underwent an intramolecular aza-nucleophilic vinyl substitution reaction, a formal [5C + 1N] annulation, to give the corresponding substituted pyridine-2,4(1H,3H)-diones in high yields, whereas in the presence of Na2S·9H2O in DMF at 75°C, tandem intermolecular and intramolecular thia-nucleophilic vinyl substitution reactions, a formal [5C + 1S] annulation, occurred to produce the corresponding substituted 4H-thiopyran-4-ones in good yields.
Magnetic Fe3O4 Nanoparticles as New, Efficient, and Reusable Catalysts for the Synthesis of Quinoxalines in Water
Authors: Lü Hong-Yan , Yang Shu-Hong , Deng Jia , Zhang Zhan-Hui
Published: August 2010

A novel, environmentally friendly procedure has been developed for the synthesis of quinoxaline derivatives in the presence of magnetic Fe3O4 nanoparticles. The reaction between 1,2-diamines and 1,2-dicarbonyl compounds was carried out in water to afford quinoxaline derivatives in high yield. The catalyst can be recovered by the use of an external magnet and reused for five cycles with almost consistent activity.
Synthesis and Characterization of Anils Exhibiting Thermochromism
Authors: Venkatachalam T. K. , Pierens Gregory K. , Reutens David
Published: August 2010

Several Schiff bases containing a hydroxy naphthyl moiety and substituted pyridyl groups were synthesized. The pyridyl substituted Schiff bases were isolated as a single stable tautomer at room temperature. High-resolution proton and carbon NMR spectroscopy showed that these compounds exist as keto tautomers. The Schiff bases showed extraordinary stability and did not convert to the enol tautomer, even at high temperatures. Most of the compounds exhibited thermochromic properties.
Nitroxide-Mediated Radical Polymerization in Nanoreactors: Can Dilution or Increased Nitroxide Concentration Provide Benefits Similar to Compartmentalization?
Authors: Zetterlund Per B.
Published: August 2010

Compartmentalization of a nitroxide-mediated radical polymerization system can lead to improved levels of both control and livingness, but at the cost of a reduced polymerization rate. Improved control is a result of the confined space effect on deactivation, whereas improved livingness stems from the segregation effect on bimolecular termination. Modelling and simulations have been carried out for the systems styrene/2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) and styrene/2,2,5-trimethyl-4-phenyl-3-azahexane-3-oxy (TIPNO) using the respective nitroxide-based polystyrene macroinitaitors (alkoxyamines) at 125°C to elucidate whether similar benefits can be obtained in the corresponding bulk polymerizations by merely diluting the systems or by addition of extra free nitroxide. The results have shown that neither approach leads to simultaneous improvement in control and livingness relative to the corresponding bulk systems, thus accentuating the merits of compartmentalization in nanoreactors.
Molecular Weight and Tacticity of Oligoacrylates by Capillary Electrophoresis - Mass Spectrometry
Authors: Gaborieau Marianne , Causon Tim J. , Guillaneuf Yohann , Hilder Emily F. , Castignolles Patrice
Published: August 2010

Oligo(acrylic acid) efficiently stabilizes polymeric particles, especially particles produced by reversible addition–fragmentation chain transfer (RAFT) (as hydrophilic block of an amphiphilic copolymer). Capillary electrophoresis (CE) has a far higher resolution power to separate these oligomers than the commonly used size exclusion chromatography. Coupling CE to electrospray ionization mass spectrometric detection unravels the separation mechanism. CE separates these oligomers, not only according to their degree of polymerization, but also according to their tacticity, in agreement with NMR analysis. Such analysis will provide insight into the role of these oligomers as stabilizers in emulsion polymerization, and into the mechanism of the RAFT polymerization with respect to degree of polymerization and tacticity.
Tribromoisocyanuric Acid (TBCA)
Authors: Hoelz Lucas V. B.
Published: August 2010

This paper provides a description of tribromoisocyanuric acid (TBCA), a new reagent used as a source of electrophilic bromine (Br+) in organic synthesis, including in Green Chemistry procedures. Its applications embrace the bromination of alkenes, β-dicarbonyl compounds and deactivated arenes, as well as oxidations of urazoles, bisurazoles, and thiols.
cDNA Microarrays - Providing Insight into Organism/Chemotherapeutic Interactions
Authors: Wright Elise P.
Published: August 2010

cDNA microarrays are a technique for interrogating gene expression responses to novel compounds, including chemotherapeutics. This holistic approach to gene expression measurement provides a genome wide appraisal of which molecular mechanisms are targeted by or associated with a drug.
Applications of RNA interference-based gene silencing in animal agriculture
Authors: Long Charles R. , Tessanne Kimberly J. , Golding Michael C.
Published: August 2010

Classical genetic selection, recently aided by genomic selection tools, has been successful in achieving remarkable progress in livestock improvement. However, genetic selection has led to decreased genetic diversity and, in some cases, acquisition of undesirable traits. In order to meet the increased demands of our expanding population, new technologies and practices must be developed that contend with zoonotic and animal disease, environmental impacts of large farming operations and the increased food and fibre production needed to feed and clothe our society. Future increases in productivity may be dependent upon the acquisition of genetic traits not currently encoded by the genomes of animals used in standard agricultural practice, thus making classical genetic selection impossible. Genetic engineering of livestock is commonly used to produce pharmaceuticals or to impart enhanced production characteristics to animals, but has also demonstrated its usefulness in producing animals with disease resistance. However, significant challenges remain because it has been more difficult to produce animals in which specific genes have been removed. It is now possible to modify livestock genomes to block expression of endogenous and exogenous genes (such as those expressed following virus infection). In the present review, we discuss mechanisms of silencing gene expression via the biology of RNA interference (RNAi), the technology of activating the RNAi pathway and the application of this technology to enhance livestock production through increased production efficiency and prevention of disease. An increased demand for sustainable food production is at the forefront of scientific challenges and RNAi technology will undoubtedly play a key role.
Systems biology of embryogenesis
Authors: Edelman Lucas B. , Chandrasekaran Sriram , Price Nathan D.
Published: August 2010

The development of a complete organism from a single cell involves extraordinarily complex orchestration of biological processes that vary intricately across space and time. Systems biology seeks to describe how all elements of a biological system interact in order to understand, model and ultimately predict aspects of emergent biological processes. Embryogenesis represents an extraordinary opportunity (and challenge) for the application of systems biology. Systems approaches have already been used successfully to study various aspects of development, from complex intracellular networks to four-dimensional models of organogenesis. Going forward, great advancements and discoveries can be expected from systems approaches applied to embryogenesis and developmental biology.
Mammalian oocyte development: checkpoints for competence
Authors: Fair Trudee
Published: August 2010

During the lifespan of the female, biochemical changes occur in the ovarian environment. These changes are brought about by numerous endogenous and exogenous factors, including husbandry practices, production demands and disease, and can have a profound effect on ovarian oocyte quality and subsequent embryo development. Despite many investigations, there is no consensus regarding the time or period of follicular oocyte development that is particularly sensitive to insult. Here, the key molecular and morphological events that occur during oocyte and follicle growth are reviewed, with a specific focus on identifying critical checkpoints in oocyte development. The secondary follicle stage appears to be a key phase in follicular oocyte development because major events such as activation of the oocyte transcriptome, sequestration of the zona pellucida, establishment of bidirectional communication between the granulosa cells and the oocyte and cortical granule synthesis occur during this period of development. Several months later, the periovulatory period is also characterised by the occurrence of critical events, including appropriate degradation or polyadenylation of mRNA transcripts, resumption of meiosis, spindle formation, chromosome alignment and segregation, and so should also be considered as a potential checkpoint of oocyte development.
Synthetic media for culture, freezing and vitrification of bovine embryos
Authors: Hasler J. F.
Published: August 2010

Media designed for the recovery, holding and cryopreservation of bovine and equine embryos are available from several commercial sources. In years past, some of these media contained bovine serum, although inclusion of serum in embryo transfer media is now largely discontinued due to issues relating to storage and biosecurity. Currently, bovine serum albumin (BSA) is included in most commercially manufactured media intended for use in embryo transfer (ET). Although BSA poses less risk than serum for the transmission of infectious disease, its inclusion still entails risk of viral contamination. The present review briefly describes the various components of ET media and the development of efficacious ET media containing no products of animal origin. An evaluation of the efficacy of recovery, holding, slow controlled freezing and vitrification media in both research and commercial ET embryo transfer settings is also presented.
100 A COMPARISON OF GLYCEROL AND EGTA FOR ULTRARAPID FREEZING OF BULL EPIDIDYMAL SPERM
Authors: Magalhães L. C. O. , Melo C. M. , Sudano M. J. , Paschoal D. M. , Crocomo L. F. , Papa F. O. , Landim-Alvarenga F. C. , Lopes M. D.
Published: August 2010

The ultrarapid freezing technique was developed as an alternative to slow conventional freezing to avoid formation of ice crystals (Tucker MJ and Liebermann J 2007, Vitrification in Assisted Reproduction, 87-92). The recent use of ethylene glycol tetraacetic acid (EGTA) instead of glycerol as a cryoprotectant for sperm is a result of efforts to reduce osmotic and cytotoxic effects. Accordingly, the objective of the present study was to compare the cryoprotective effects of EGTA v. glycerol on bovine sperm frozen using an ultrarapid method. A pool of epididymal sperm collected from 5 bulls was maintained in Botusui extender (Biotech, Botucatu, Brazil) containing 5% BSA, either EGTA (5%) or glycerol (5%), and 0 or 2 mg mL of polyvinyl alcohol (PVA). All samples were loaded into 0.25-mL French straws and either placed into a freezing machine (TK 4000 compacta, TK equipamentos para reproducao, Uberaba, Brazil) and cooled at a rate of 50°C/min, or exposed to liquid nitrogen (LN2) vapor for 5 to 15 min before plunging into LN2. After overnight storage in LN2, straws were thawed and examined using CASA (HTM IVOS 12, Hamilton Thorne Research, Beverly, MA, USA) for total motility (TM), progressive motility (PM), path velocity (VAP), progressive velocity (VSL), and track speed (VCL). Acridine Orange (AO) was used to check DNA integrity of sperm cells (Chirinea VH et al. 2006 Ciencia Animal Brasileira 7, 407-415). Our results indicate that, despite the potentially damaging effects of the extreme temperature changes, epididymal sperm showed 95% of DNA integrity and, therefore, should be able to participate in the fertilization process. Addition of PVA had a negative effect on sperm motility characteristics. CASA revealed that glycerol was a more suitable cryoprotectant for ultrarapid freezing of bull epididymal spermatozoa than was EGTA (see Table 1).

Table 1.

CAPES.
101 EFFECT OF NITROCOOLER NEGATIVE PRESSURE AND RECOVERY INTERVAL ON CRYOTOLERANCE OF BOVINE IN VITRO-PRODUCED EMBRYOS
Authors: Mezzalira J. C. , Ohlweiler L. U. , Urio M. , Neto S. G. , Marinho L. R. , Zago F. C. , Forell F. , Bertolini M. , Mezzalira A.
Published: August 2010

Exposing bovine embryos and porcine oocytes to hydrostatic pressure has been shown to increase cryosurvival, possibly by a resulting expression of stress tolerance proteins. This study aimed to evaluate the effect of the negative pressure stress condition (a 5-min-long embryo exposure to a negative pressure) and the interval between vacuum exposure and vitrification (40 min or 2 h) on survival of bovine in vitro-produced (IVP) embryos. The negative pressure was achieved with the same apparatus used previously for the cryopreservation of embryos (Nitrocooler; Mezzalira et al. 2009 Reprod. Fert. Dev. (1) 134), in which a negative pressure (vacuum) is applied to liquid nitrogen to increase the cooling rate through the slush phenomenon, except that in this study, the vacuum was applied to the chamber without liquid nitrogen, at room temperature. Grades 1 and 2 bovine IVP expanded blastocysts were allocated to 1 of 5 experimental groups: embryos in vitro-cultured as fresh (control) or after vitrification (Vitri); and embryos subjected to the negative pressure for 5 min and then in vitro-cultured as fresh (NP-fresh) or after vitrification performed 40 min (NP-Vitri-40 min) or 2 h (NP-Vitri-2h) following the vacuum exposure. Embryos were vitrified in pulled glass micropipettes in a solution with 20% ethylene glycol + 20% dimethylsulfoxide + 20% fetal bovine serum and rewarmed in decreasing sucrose concentrations (Mezzalira et al. 1999 Acta Scientiae Veterinariae 27 262-262). In vitro culture was carried out in all treatments for 72 h for the assessment of re-expansion and hatching rates (Table 1), which were analyzed by the chi-square test, for P < 0.05. No differences in re-expansion rates were observed between groups. However, the vitrification of embryos after 2 h of exposure to a 5-min-long negative pressure (NP-Vitri-2h) improved embryo survival expressed by a higher hatching rate than for embryos vitrified without vacuum exposure (Vitri) or after 40 min following the 5-min-long exposure to vacuum. In addition, hatching rates in group NP-Vitri-2h were similar to those for fresh embryos (control and NP-fresh). Our results indicated that a short exposure of embryos to a negative pressure can improve cryotolerance following vitrification, which is dependent on the time interval between NP exposure and cryopreservation. Bovine IVP embryos should be allowed to recover for at least 2 h after NP exposure before the increase in cryotolerance is achieved.

Table 1.Effect of negative pressure on re-expansion and hatching rates of fresh and vitrified
106 PREGNANCY RATE AFTER EMBRYO TRANSFER OF IN VIVO-PRODUCED OVINE EMBRYOS CRYOPRESERVED BY SLOW FREEZING OR VITRIFICATION
Authors: Mucci N. , Hozbor F. , Kaiser G. G. , Sanchez E. , Alberio R. H.
Published: August 2010

Although slow freezing is the method of choice to cryopreserve in vivo-produced ovine embryos, vitrification has became an alternative procedure mostly developed for in vitro-produced bovine embryos. The aim of this work was to compare pregnancy rates after cryopreservation of in vivo-produced ovine embryos with slow freezing or open pulled straw (OPS) vitrification method. Ewes were synchronized using intravaginal sponges containing 60 mg of medroxyprogesterone acetate for 14 d. Superovulation was performed using a total dose of 176 IU of ovine FSH (Ovagen), in 6 decreasing doses (i.m.) from Day 12 to 14 of treatment (Day 0 = sponge placing). Ewes were hand mated with 2 rams of proven fertility. Embryos were recovered 6 days after estrous detection by surgical procedure, evaluated under stereomicroscope, and randomly assigned to the cryopreservation treatments. Slow freezing was performed in D-PBS supplemented with 1.78 M ethylene glycol, 0.1 M sucrose, 4 mg mL-1 of BSA, and 20% serum. Embryos were loaded into 0.25-mL plastic straws and placed into a -7°C methanol bath chamber. After seeding embryos were cooled to -35°C at a rate of 0.5°C/min and then stored in liquid nitrogen. Thawing was performed by placing the straws in a 30°C water bath for 30 sec. Vitrification was performed by using the OPS method (Vajta et al. 1998) with minor modifications. Embryos were incubated in D-PBS supplemented with 1.78 M ethylene glycol, 1.3 M DMSO for 3 min and then transferred for 25 s in vitrification solution of D-PBS with 3.56 M ethylene glycol, 2.6 M DMSO, and 0.5 M sucrose, loaded in a 1 mL drop in the OPS, and immediately submerged into and stored in liquid nitrogen. Warming was performed in D-PBS plus 0.25 M sucrose for 5 min and then into D-PBS plus 0.15 M sucrose for another 5 min. Before embryo transfer, the presence of corpus luteum (CL) was detected by laparoscopic examination. One embryo per recipient was surgically transferred in the apical extreme of the uterine horn ipsilateral to the CL. Pregnancies were determined by ultrasonography 41 days after embryo transfer. Data were analyzed using the chi-square test. We found 47.8% pregnancy rate using slow freezing (11/23) and 43.5% pregnancy rate using OPS vitrification (10/23). Statistical differences were not detected (P = 0.09). We conclude that vitrification by OPS system, with minor modifications, is a suitable procedure for in vivo-produced ovine embryo cryopreservation.
109 ASSESSMENT OF THE FUNCTIONALITY OF PLASMA MEMBRANE OF CRYOPRESERVED SPERM FROM DIFFERENT BREEDS OF SHEEP
Authors: Pimenta Neto F. C. , Frazão Sobrinho J. M. , Moraes Junior F. J. , Oliveira R. A. , Souza J. A. T. , Nicacio A. C.
Published: August 2010

Sperm cryopreservation is very important to genetic material quality dissemination. However, the spermatozoa can be damaged during this process. The objective of this study was to investigate the functionality of spermatozoa plasmatic membrane of ovine after cryopreservation. The work was conducted at Laboratory of Reproduction Biotechnology, Veterinary Medicine course, Federal University of Piaui. Fifteen animals were used (5 Dorper, 5 Santa Inês, and 5 animals of undefined breed - SRD). The animals were between 2 and 3 years old, and only one ejaculate was used per animal. Semen was collected via artificial vagina and frozen in cryopreservation machine (TK 3000®, OV curve 2), with Tris-yolk base extend and glycerol. The semen was evaluated before and after cryopreservation. To investigate the functionality of spermatozoa plasmatic membrane hypo-osmotic test (HOST) was used. After thawing, 20 μL of semen was incubated in 2 mL of hypoosmotic solution (125 mOsmol L-1) and 20 μL of semen was incubated in a 4% formalide citrate solution at 37°C for 1 h. After incubations, both samples were placed on microscopic slides, and 200 cells were visually evaluated per slide. Data were analyzed by Tukey-Kramer test (parametric data) and Dunn test (no parametric data) by Grafpad Instat® software. The motility averages after thawing were 36 ± 15.2% (Dorper), 36 ± 19.5% (Santa Inês), and 21 ± 14.3% (SRD). If the plasma membrane over the principal piece is intact, the membrane will swell, causing the tail to coil, whereas spermatozoa with damaged principal piece membranes will not swell. The HOST averages were 24.2 ± 11.8% (Dorper), 21% ± 6.4 (Santa Inês), and 10.4 ± 1.6% (SRD). Motility and HOST showed positive correlation (P < 0.001). The SRD animals showed higher correlation numbers than other groups (P < 0.009). The HOST is a cheap, easy, and efficient technique to estimate the functionality of sperm plasmatic membrane. We suggest that other studies could be done with more animals and more samples.