Electrochemical principles for active control of liquids on submillimeter scales     

BS Gallardo  VK Gupta  FD Eagerton  LI Jong  VS Craig  RR Shah  NL Abbott 《Science (New York, N.Y.)》1999,283(5398):57-60

Electrochemical methods were combined with redox-active surfactants to actively control the motions and positions of aqueous and organic liquids on millimeter and smaller scales. Surfactant species generated at one electrode and consumed at another were used to manipulate the magnitude and direction of spatial gradients in surface tension and guide droplets of organic liquids through simple fluidic networks. Solid microparticles could be transported across unconfined surfaces. Electrochemical control of the position of surface-active species within aqueous films of liquid supported on homogeneous surfaces was used to direct these films into periodic arrays of droplets with deterministic shapes and sizes.  相似文献   

Thyroxine concentrations are elevated in mares which continue to exhibit estrous cycles during the nonbreeding season     

B.P. Fitzgerald BSc  PhD  L.A. Davison BS  MS 《Journal of Equine Veterinary Science》1998,18(1):48-51

In two successive years, the pattern of secretion of thyroxine was compared in seasonally anestrous mares and a subpopulation of mares that exhibited estrous cycles during the nonbreeding season. Blood samples were collected two or three times per week between October and April from a total of 15 mares that exhibited estrous cycles during the nonbreeding season and 21 anestrous mares. Monthly mean concentrations of thyroxine during the period from October through April were greater (p<0.05) in cycling versus anestrous mares. However, it remains to be determined whether continuation of estrous cycles during the nonbreeding season and elevated concentrations of thyroxine are causally related.  相似文献   

Haematological and gill responses to an experimental infection of dactylogyrid monogeneans on the spotted rose snapper Lutjanus guttatus (Steindachner, 1869)     

Oscar B Del Rio‐Zaragoza  Emma J Fajer‐Avila  Pablo Almazán‐Rueda 《Aquaculture Research》2010,41(11):1592-1601

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Deep-Sea Anemones Are Prospective Source of New Antimicrobial and Cytotoxic Compounds     

Aleksandra Kvetkina  Elena Kostina  Irina Gladkikh  Victoria Chausova  Ekaterina Yurchenko  Irina Bakunina  Mikhail Pivkin  Stanislav Anastyuk  Roman Popov  Margarita Monastyrnaya  Emma Kozlovskaya  Marina Isaeva  Pavel Dmitrenok  Elena Leychenko 《Marine drugs》2021,19(12)

The peculiarities of the survival and adaptation of deep-sea organisms raise interest in the study of their metabolites as promising drugs. In this work, the hemolytic, cytotoxic, antimicrobial, and enzyme-inhibitory activities of tentacle extracts from five species of sea anemones (Cnidaria, orders Actiniaria and Corallimorpharia) collected near the Kuril and Commander Islands of the Far East of Russia were evaluated for the first time. The extracts of Liponema brevicorne and Actinostola callosa demonstrated maximal hemolytic activity, while high cytotoxic activity against murine splenocytes and Ehrlich carcinoma cells was found in the extract of Actinostola faeculenta. The extracts of Corallimorphus cf. pilatus demonstrated the greatest activity against Ehrlich carcinoma cells but were not toxic to mouse spleen cells. Sea anemones C. cf. pilatus and Stomphia coccinea are promising sources of antimicrobial and antifungal compounds, being active against Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus, and yeast Candida albicans. Moreover, all sea anemones contain α-galactosidase inhibitors. Peptide mass fingerprinting of L. brevicorne and C. cf. pilatus extracts provided a wide range of peptides, predominantly with molecular masses of 4000–5900 Da, which may belong to a known or new structural class of toxins. The obtained data allow concluding that deep-sea anemones are a promising source of compounds for drug discovery.  相似文献   

ASAS-NANP SYMPOSIUM: Review of systems thinking concepts and their potential value in animal science research     

Emma C Stephens 《Journal of animal science》2021,99(2)

Worldwide, our collective research and policy institutions, including the American Society of Animal Science (ASAS), are calling for more systems-based research and analysis of society’s most pressing and complex problems. However, the use of systems analysis within animal science remains limited and researchers may not have the tools to answer this call. This review thus introduces important concepts in systems thinking methodology, such as policy resistance, feedback processes, and dynamic complexity. An overall rationale for systems thinking and analysis is presented, along with examples of the application of these concepts in current animal science research. In order to contrast systems approaches to more frequently employed event-oriented research frameworks, both frameworks are then applied to the ASAS’ identified “Grand Challenge” problem of antimicrobial resistance (AMR) in order to compare these two kinds of analyses. Systems thinking stresses the importance of underlying system structures that lead to persistent problem behaviors vs a focus on unidirectional cause-and-effect relationships. A potential systems framework for animal production decisions to use antimicrobials is shown that more explicitly accounts for AMR in a way that can lead to different animal production decisions than the event-oriented framework. Acknowledging and accounting for fundamental system structures that can explain persistent AMR will lead to different potential solutions to this problem than would be suggested from more linear approaches. The challenges and benefits of incorporating systems methods into animal science research are then discussed.  相似文献   

The effect of pre-dosing with metformin on the insulin response to oral sugar in insulin-dysregulated horses     

Sarah F. Colmer  Amanda A. Adams  Emma Adam  Rachel Miller  Darko Stefanovski  Jeaneen C. Kulp  Andrew van Eps 《Equine veterinary journal》2024,56(2):318-325

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Response of laying hens to L-arginine,L-citrulline and guanidinoacetic acid supplementation in reduced protein diet     

Hiep Thi Dao  Nishchal K. Sharma  Emma J. Bradbury  Robert A. Swick 《动物营养（英文）》2021,7(2):460

A study was conducted with Hy-Line Brown laying hens to examine the effects of reduced protein diet, deficiency of arginine (Arg), and addition of crystalline Arg, citrulline (Cit) and guanidinoacetic acid (GAA) as substitutes for Arg. Hen performance, egg quality, serum uric acid, liver and reproductive organ weights, and energy and protein digestibility were measured using a completely randomized design with 5 treatments. Treatments were a standard diet (17% protein diet; SP), a reduced diet (13% protein diet deficient in Arg; RP) and RP with added Arg (0.35%, RP-Arg), GAA (0.46% equivalent to 0.35% Arg, RP-GAA) or Cit (0.35%, RP-Cit) to the level of SP. It was hypothesized that performance would decrease with Arg deficient RP diet and the addition of GAA or Cit in RP would allow birds to perform similar or greater than Arg-added RP treatment. The experiment was conducted from 20 to 39 wk of age but the treatment effect was seen only after 29 wk of age. The birds offered RP had reduced egg and albumin weights (P < 0.01), lower yolk color score (P < 0.01), lower protein intake and excretion (P < 0.01) than those offered SP. When Arg or Cit were added to RP to make them equivalent to SP, feed intake (FI) and egg production were not different than those of RP (P > 0.05). The birds offered RP-GAA decreased FI and egg production (P < 0.01) compared to those offered RP. The addition of Arg, Cit or GAA to the RP had no effect on egg quality parameters, protein and energy digestibilities (P > 0.05). However, birds offered the RP-Cit diet tended to have higher Haugh unit (P = 0.095) and lower shell breaking strength (P = 0.088) compared to all other treatments while those offered RP-GAA had higher energy digestibility (P < 0.05) than all other groups but RP. The limited performance response of hens fed RP with added Arg, GAA, or Cit may be due to deficiency of some other nutrients in RP such as phenylalanine, potassium or non-essential amino acids and other components of soybean meal in the diet.  相似文献   

High diversity and clonality are hallmarks of Fusarium circinatum in South Africa     

Felix F. Fru  Michael J. Wingfield  Jolanda Roux  Emma T. Steenkamp 《Plant pathology》2023,72(1):39-52

Pitch canker on plantation-grown Pinus species, caused by the fungal pathogen Fusarium circinatum, first appeared in the western and southern Cape regions of South Africa. However, outbreaks have subsequently been reported from the major plantation growing regions of KwaZulu-Natal and Limpopo in the eastern, summer rainfall regions of the country. It is more than 10 years since the last detailed population genetics studies on F. circinatum in the region were conducted. To shed light on the population biology of F. circinatum in this region of South Africa, we used microsatellite markers and mating-type assays to study a collection of 296 isolates from different nurseries and plantation sites. Our results showed that populations in the region are highly diverse, but strongly interconnected, with various genotypes shared across nursery and plantation collection sites. In contrast to nursery populations, those associated with pitch canker outbreaks were characterized by the presence of relatively small numbers of dominant genotypes that were generally widespread across the region. Opposite mating-type individuals occurred in most of the isolate collections, but multilocus linkage disequilibrium analyses pointed towards clonality being the main reproductive mode of F. circinatum in the region. Most of the pathogen's genetic variation could probably have resulted from multiple different introductions into the country and more specifically, into the summer rainfall region. Because the spread and establishment of invasive pathogens are typically driven by aggressive clones, the results of this study provide important considerations for current and future Pinus disease management strategies.  相似文献