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María García-Altares Alexis Casanova Vaishali Bane Jorge Diogène Ambrose Furey Pablo de la Iglesia 《Marine drugs》2014,12(6):3706-3732
Cyclic imines are lipophilic marine toxins that bioaccumulate in seafood. Their structure comprises a cyclic-imino moiety, responsible for acute neurotoxicity in mice. Cyclic imines have not been linked yet to human poisonings and are not regulated in Europe, although the European Food Safety Authority requires more data to perform a conclusive risk assessment for consumers. This work presents the first detection of pinnatoxin G (PnTX-G) in Spain and 13-desmethyl spirolide C (SPX-1) in shellfish from Catalonia (Spain, NW Mediterranean Sea). Cyclic imines were found at low concentrations (2 to 60 µg/kg) in 13 samples of mussels and oysters (22 samples analyzed). Pinnatoxin G has been also detected in 17 seawater samples (out of 34) using solid phase adsorption toxin tracking devices (0.3 to 0.9 µg/kg-resin). Pinnatoxin G and SPX-1 were confirmed with both low and high resolution (<2 ppm) mass spectrometry by comparison of the response with that from reference standards. For other analogs without reference standards, we applied a strategy combining low resolution MS with a triple quadrupole mass analyzer for a fast and reliable screening, and high resolution MS LTQ Orbitrap® for unambiguous confirmation. The advantages and limitations of using high resolution MS without reference standards were discussed. 相似文献
44.
Shane Dennis Lisa K. Pearson Alexis J. Campbell Ahmed Tibary 《Journal of Equine Veterinary Science》2014
Outbreaks of both equine viral arteritis and contagious equine metritis (CEM) in the United States have occurred in recent years. Shipped semen has been implicated in disease transmission and rapid spread. A survey was performed of state regulations regarding testing for equine arteritis virus (EAV) and CEM before interstate semen or embryo shipment. Results demonstrated lack of any requirements in 31 states. Four states had regulations regarding EAV; 17 required a Certificate of Veterinary Inspection (CVI) to accompany a semen or embryo shipment. Ten states required a negative equine infectious anemia test, primarily as a requirement of a CVI versus because of risk of dissemination of disease. No states required CEM testing. A comparison of state department of agriculture or veterinary medical association Web sites and direct communication with state veterinarians or their offices demonstrated contradictory information in six states. The lack of uniform regulations concerning CEM and EAV testing for shipped semen and embryos, and the threat they pose to the equine breeding industry and horse health, should be alarming to veterinarians and horse owners. Routine testing of animals before shipment of semen or embryos and veterinary involvement in collection and breeding activities are appropriate and necessary to help prevent future outbreaks and protect equine health. 相似文献
45.
Socoliuc A Gnecco E Maier S Pfeiffer O Baratoff A Bennewitz R Meyer E 《Science (New York, N.Y.)》2006,313(5784):207-210
Stiction and wear are demanding problems in nanoelectromechanical devices, because of their large surface-to-volume ratios and the inapplicability of traditional liquid lubricants. An efficient way to switch friction on and off at the atomic scale is achieved by exciting the mechanical resonances of the sliding system perpendicular to the contact plane. The resulting variations of the interaction energy reduce friction below 10 piconewtons in a finite range of excitation and load, without any noticeable wear. Without actuation, atomic stick-slip motion, which leads to dissipation, is observed in the same range. Even if the normal oscillations require energy to actuate, our technique represents a valuable way to minimize energy dissipation in nanocontacts. 相似文献
46.
We report on a wind-tunnel study with 1 : 75 scale model treesdesigned to examine the influence of canopy structure on theformation of turbulent gusts above forests. This was to testthe hypothesis that more irregular canopy structures produceless intense gusts because the change in wind speed with heightat canopy top is less severe. Measurements were made of windspeeds and turbulence within and above the model forests andof the wind loading on model trees in four different silviculturalsystems. The systems tested were even-aged, single-tree selection,shelterwood/group selection and strip felling. The measurementsshowed that the profiles of different mean wind and turbulencecharacteristics above the forests are remarkably similar whenvertical heights are normalized by the height of the tallesttree but differences do exist within the canopy. The wind loadingmeasurements indicated no difference between the systems interms of stability except possibly for the shelterwood/groupselection. In the shelterwood/group selection system the presenceof smaller sub-canopy trees appears to reduce the loading onthe main canopy trees either by providing support and increasingdamping or by absorption of energy from the canopy-penetratinggusts. 相似文献
47.
Jean Raphael Kana Alexis Teguia Berrian Musa Mungfu Joseph Tchoumboue 《Tropical animal health and production》2011,43(1):51-56
Growth performances and carcass characteristics of broiler chickens fed diets supplemented with graded levels of Canarium schweinfurthii Engl seed (charcoal A) or maize cob (charcoal B) were studied using a total of 110 3-week-old male chicks. 11 experimental
diets including a control and other containing either 0.2, 0.4, 0.6, 0.8 or 1% charcoal from C. schweinfurthii Engl seed (A0.2, A0.4, A0.6, A0.8, and A1%, respectively) or from maize cob (B0.2, B0.4, B0.6, B0.8, and B1%, respectively) supplements were used. Each of the diets was fed to ten individually birds caged in a completely randomized
design. Results indicated that birds fed 0.2, 0.4, and 0.6% of either charcoal A or B had significantly (P < 0.05) higher final body weights as compared to control birds, while, above 0.6% slightly depressed average final body weights
and weight gain. The best growth performance was achieved with 0.2% inclusion of charcoals. There was no significant (P > 0.05) influence of charcoal B on the overall feed intake. Only the B0.6 feed significantly (P < 0.05) improved feed conversion ratio as compared with the control. Dressing percentage, liver weight and abdominal fat
were not significantly (P > 0.05) affected by charcoal. However, there was a significant (P < 0.05) reduction in gizzard weight with charcoal B. Charcoal had no significant (P > 0.05) influence on intestine length and weight. More than 0.6% of charcoal A significantly (P < 0.05) depressed intestine density. It was concluded that under the conditions of this study, charcoal from maize cob or
Canarium seeds could be used to improve growth performances and some carcass traits in broiler chickens. 相似文献
48.
Canine distemper and pulmonary sarcocystosis were diagnosed in a 10-week-old Rottweiler with 4-day history of diarrhea, vomiting, and weakness. Microscopic examination of the lung revealed bronchointerstitial pneumonia typical of morbillivirus infection. Also, numerous apicomplexan parasites were scattered in the alveolar walls. This protozoan infection was first thought to be toxoplasmosis but immunoperoxidase staining revealed large numbers of Sarcocystis canis. This is the first case of canine sarcocystosis reported from Latin America that further emphasizes the importance of immunohistochemistry in the differential diagnoses of apicomplexan infections in dogs. 相似文献
49.
Teodulo González-Quirino José Alberto Delgadillo José Alfredo Flores Jesús Vielma Gerardo Duarte Manuel de Jesús Flores Angélica Terrazas Luis Angel Zarazaga Alexis Adrián Vargas-Cruz Ricardo Avilés Horacio Hernández 《Animal Science Journal》2021,92(1):e13646
The present experiments on goats were conducted with the aim of verifying (a) whether the identity of the goat kids can affect the characteristics of milk let-down during suckling (Study 1) and (b) whether the presence of the goat kids may improve the milk let-down during hand milking (Study 2). In Study 1, 16 lactating goats with twins and 12 with single kids were used. Dams with single goat kids ejected more milk when suckling their kids at Days 5 and 20 of lactation, than when suckling aliens. Dams with twins ejected more milk when suckling their own kids than aliens only at Day 5 of lactation. Taking into account all the dams, they ejected more milk with more fat, protein, and lactose during suckling their own litter than when suckling aliens. In Study 2, when dams (n = 13) were hand milked in the presence of their own litter or in its absence, they ejected more milk with more fat, protein, and lactose than when milked in the presence of alien kids. We conclude that milk let-down in goats can be influenced by the type of stimuli applied or to which they are exposed to during suckling and milking. 相似文献
50.
Jacquie L. Harper Iman M. Khalil Lisa Shaw Marie-Lise Bourguet-Kondracki Jo?lle Dubois Alexis Valentin David Barker Brent R. Copp 《Marine drugs》2015,13(8):5102-5110
In an effort to more accurately define the mechanism of cell death and to establish structure-activity relationship requirements for the marine meroterpenoid alkaloids thiaplidiaquinones A and B, we have evaluated not only the natural products but also dioxothiazine regioisomers and two precursor quinones in a range of bioassays. While the natural products were found to be weak inducers of ROS in Jurkat cells, the dioxothiazine regioisomer of thiaplidiaquinone A and a synthetic precursor to thiaplidiaquinone B were found to be moderately potent inducers. Intriguingly, and in contrast to previous reports, the mechanism of Jurkat cell death (necrosis vs. apoptosis) was found to be dependent upon the positioning of one of the geranyl sidechains in the compounds with thiaplidiaquinone A and its dioxothiazine regioisomer causing death dominantly by necrosis, while thiaplidiaquinone B and its dioxothiazine isomer caused cell death via apoptosis. The dioxothiazine regioisomer of thiaplidiaquinone A exhibited more potent in vitro antiproliferative activity against human tumor cells, with NCI sub-panel selectivity towards melanoma cell lines. The non-natural dioxothiazine regioisomers were also more active in antiplasmodial and anti-farnesyltransferase assays than their natural product counterparts. The results highlight the important role that natural product total synthesis can play in not only helping understand the structural basis of biological activity of natural products, but also the discovery of new bioactive scaffolds. 相似文献