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991.
Anna-Sara Krng Susanne P. Baden 《Journal of experimental marine biology and ecology》2004,310(2):195-206
The amphipod Corophium volutator (Pallas) is a tube-dwelling species that only occasionally leaves its burrow. Animals that do crawl on the sediment are mainly males, apparently in search of females. This study was designed to determine whether C. volutator males and females release chemical signals that attract con-specifics, and if so, whether these signals are gender specific. Laboratory experiments were conducted on the over-wintering generation during their reproductive season, using a Y-maze choice test apparatus. The results show that C. volutator females release chemical signals that attract males. In the field, the attractant may guide males in search of burrowed females. In addition, male odour tends to attract males, while females do not follow chemical signals from con-specifics. We thereby show on gender-specific chemical attraction of this species. 相似文献
992.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):489-505
Abstract The current achievement of genome sequence projects of a dozen eukaryote organisms (including human genome) and the development of functional genomics are providing the basic knowledge required to utilize gene-specific reagents for both basic understanding of cell physiology and therapeutical development. The field of chemical genomics has the ambitious goal of designing molecules that could act selectively on every single gene or gene product in a cell and in vivo. The progress in oligonucleotide-based approaches will be the topic of this review, however, other nucleic acid- and SELEX-based approaches as well as high sequence-specific low molecular weight DNA-specific ligands will also be discussed. 相似文献
993.
Nadine Barroca-Aubry 《Carbohydrate research》2010,345(12):1685-1697
The total chemical synthesis of the four well-defined chitodisaccharides is described using N-trichloroacetyl (TCA) and N-benzyloxycarbonyl (Z) as C-2 protecting groups for acetamido and free amino groups, respectively. The synthesis is carried out according to a strategy that paves way to the elaboration of various homo- and hetero-chitooligosaccharides, with perfect control of the number and the position of GlcN and GlcNAc units along the oligomer chain. 相似文献
994.
《Journal of biological education》2012,46(2):89-92
Increase in recreational demand on the countryside makes the monitoring of resulting change in vegetation of value, especially in areas of recognized ecological importance. Methods are described for an initial survey of trampling pressure and soil compaction, and their effects on both the soil environment and the plant community structure. With reference to a dune slack habitat the response of the vegetation to trampling levels is assessed by linear regression analysis. Variation in diversity is noted together with changes in the ratio between monocotyledons and dicotyledons. Occurrence indices may be used to identify the species resistant to trampling; these, in general, are found to adopt a hemicryptophytic or therophytic growth form. Such studies can make a useful contribution to field investigations for older secondary school and undergraduate students, and provide starting points for further detailed investigations. 相似文献
995.
Hidayah Ariffin Dr. Haruo Nishida Mohd Ali Hassan Yoshihito Shirai 《Biotechnology journal》2010,5(5):484-492
Chemical recycling of bio-based polymers polyhydroxyalkanoates (PHAs) by thermal degradation was investigated from the viewpoint of biorefinery. The thermal degradation resulted in successful transformation of PHAs into vinyl monomers using alkali earth compound (AEC) catalysts. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)s (PHBVs) were smoothly and selectively depolymerized into crotonic (CA) and 2-pentenoic (2-PA) acids at lower degradation temperatures in the presence of CaO and Mg(OH)2 as catalysts. Obtained CA from 3-hydroxybutyrate sequences in PHBV was copolymerized with acrylic acid to produce useful water-soluble copolymers, poly(crotonic acid-co-acrylic acid) that have high glass-transition temperatures. The copolymerization of CA derived from PHA pyrolysis is an example of cascade utilization of PHAs, which meets the idea of sustainable development. 相似文献
996.
While pheromone communication has been well documented in the female round goby, male responses have not been examined. We
determined if male round gobies responded to odours of their conspecifics, and whether that response varied with their reproductive
status (reproductive and non-reproductive). No significant differences were observed for any treatment (dechlorinated water,
or water conditioned by reproductive males (RM) and non-reproductive males (NRM) and females), although RM spent more time
inside shelter than NRM (p < 0.05). Morphologically, length and weight did not vary, but gonadosomatic index, seminal vesicle somatic index and relative
head width did differ between the two male groups (p = 0.000). Round goby males guard nests in cavities, and so a preference for shelter with increasing reproductive status is
expected. Also, a lack of male responses to conspecific odours may be adaptive in this species, since males nest together
in high densities, where increased aggression might prove detrimental for nesting males. 相似文献
997.
Cerrado is a savanna ecosystem of central and southeastern Brazil. Many woody species of cerrado have thick layers of cork. The present work aimed to characterize, by GC/MS analysis, the constituents of n-hexane extracts from the cork of common species from cerrado. Cork samples from 31 individuals, corresponding to 14 species and six families, were analyzed. Similarities and differences were noticed between cork and cuticular waxes regarding profiles of lipophilic constituents. The distribution of cork constituents was analyzed using the UPGMA clustering method and DICE coefficient. All clusters in the dendrogram obtained comprise individuals from a same species, suggesting that the distribution of lipophilic cork constituents is useful for species characterization and possibly also for species identification, resembling results commonly obtained with molecular markers. Seven samples of Bignoniaceae, corresponding to two genera and seven species, emerged in a common cluster, in an arrangement in accordance with the recent segregation of Tabebuia species to a new genus Handroanthus. The markers analyzed were not efficient regarding characterization of other families. 相似文献
998.
《Revista espa?ola de geriatría y gerontología》2020,55(6):354-357
Chemical Submission (CS) is considered a danger to health and a form of violence. There are different forms of proactive CS (involuntary consumption of psychoactive substances) and opportunistic CS (voluntary consumption), with criminal intent, usually theft, submission, or sexual assault. The objective of this work is to describe the characteristics of cases of suspected CS in adults older than 65 years treated in the Emergency Department of the San Carlos Clinical Hospital and the results of the toxicological analysis performed by the INTCF in Madrid (April 1, 2015-2019). There were 12 (8%) cases of suspected CS, with a mean age of 75 (SD 8) years, of which 8 (66.7%) men, with two different profiles, all associated with theft, and in 3 (25%) possible sexual assault. In 9 (75%) cases, benzodiazepines and / or usual drugs were identified. CS is a problem to consider in Emergency Departments and is not exclusive to the young population. 相似文献
999.
Tarun Kumar Verinder Wahla Piyush Pandey R. C. Dubey D. K. Maheshwari 《World journal of microbiology & biotechnology》2009,25(2):277-285
Biological control of the cyst forming nematode Heterodera cajani was studied on sesame using plant growth promoting rhizobacteria (PGPR) Pseudomonas aeruginosa LPT3 and LPT5. Based on plant growth promoting attributes, two fluorescent pseudomonads, LPT3 and LPT5 were evaluated for
their efficacy against cyst forming nematode Heterodera cajani that parasitize Sesamum indicum. Pseudomonas aeruginosa LPT5 produced IAA, HCN, chitinase, glucanase and siderophore, and also solubilized inorganic phosphate in vitro. Moreover,
LPT5 resulted in mortality of second stage juveniles of H. cajani, which was 13% higher as compared to P. aeruginosa LPT3. Interestingly, when both strains were inoculated together for the management of H. cajani on Sesamum indicum the population of H. cajani was reduced significantly, in field trial. Approximately 60% reduction in cyst and juveniles population was recorded with
LPT5 coated seeds, while LPT3 resulted in 49% reduction in cyst and juvenile population as compared to control. Plants grown
with seeds bacterized with LPT5 and reduced doses of urea, diammonium phosphate (DAP), muriate of potash (K) and gypsum gave
maximum increase in yield, in comparison to that of plants raised under the influence of recommended or full doses of the
chemical fertilizers. Pseudomonas aeruginosa LPT5 also showed excellent root colonization. 相似文献
1000.
Geoffrey Diederich Timothy O'Connor Pavel Moroz Erich Kinder Elena Kohn Dimuthu Perera Ryan Lorek Scott Lambright Martene Imboden Mikhail Zamkov 《Journal of visualized experiments : JoVE》2012,(66)
Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials offering a superior control over the spatial distribution of charge carriers across material interfaces. As this study demonstrates, a combination of donor-acceptor nanocrystal (NC) domains in a single nanoparticle can lead to the realization of efficient photocatalytic1-5 materials, while a layered assembly of donor- and acceptor-like nanocrystals films gives rise to photovoltaic materials.Initially the paper focuses on the synthesis of composite inorganic nanocrystals, comprising linearly stacked ZnSe, CdS, and Pt domains, which jointly promote photoinduced charge separation. These structures are used in aqueous solutions for the photocatalysis of water under solar radiation, resulting in the production of H2 gas. To enhance the photoinduced separation of charges, a nanorod morphology with a linear gradient originating from an intrinsic electric field is used5. The inter-domain energetics are then optimized to drive photogenerated electrons toward the Pt catalytic site while expelling the holes to the surface of ZnSe domains for sacrificial regeneration (via methanol). Here we show that the only efficient way to produce hydrogen is to use electron-donating ligands to passivate the surface states by tuning the energy level alignment at the semiconductor-ligand interface. Stable and efficient reduction of water is allowed by these ligands due to the fact that they fill vacancies in the valence band of the semiconductor domain, preventing energetic holes from degrading it. Specifically, we show that the energy of the hole is transferred to the ligand moiety, leaving the semiconductor domain functional. This enables us to return the entire nanocrystal-ligand system to a functional state, when the ligands are degraded, by simply adding fresh ligands to the system4.To promote a photovoltaic charge separation, we use a composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer6. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells7. 相似文献