排序方式： 共有27条查询结果，搜索用时 15 毫秒
1.
The structures of hexaazaoctadecahydrocoronene, [HAOC](n) (n = O, + 2), have been determined by single-crystal x-ray diffraction. Although HAOC is aromatic, its dication has a localized structure that is based upon Jahn-Teller-distorted cyanine/p-phenylenediammonium fragments. The structure is consistent with the singlet ground state as determined by magnetic susceptibility and contrasts with the simplest Hückel expectation of a triplet ground state. 相似文献
2.
Radar soundings of the subsurface of Mars 总被引：2，自引：0，他引：2
Picardi G Plaut JJ Biccari D Bombaci O Calabrese D Cartacci M Cicchetti A Clifford SM Edenhofer P Farrell WM Federico C Frigeri A Gurnett DA Hagfors T Heggy E Herique A Huff RL Ivanov AB Johnson WT Jordan RL Kirchner DL Kofman W Leuschen CJ Nielsen E Orosei R Pettinelli E Phillips RJ Plettemeier D Safaeinili A Seu R Stofan ER Vannaroni G Watters TR Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928
The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick. 相似文献
3.
Silva-Almeida M Carvalho LO Abreu-Silva AL Souza CS Hardoim DJ Calabrese KS 《Veterinary research》2012,43(1):10
ABSTRACT: Leishmania is inoculated, by the bite of an infected sandfly, into the skin of the host, where the promastigotes are phagocyted by dermal macrophages. The dermal region comprises cells and abundant extracellular matrix. Studies show that matrix metalloproteinases play an important role in host defense responses against pathogens in mammals and that their activities lead to the production of antimicrobial peptides. The aim of this study is to evaluate the changes in the distribution of fibronectin and laminin as well as in the elastic system fibres during the course of infection caused by Leishmania amazonensis in mice with distinct genetic backgrounds of susceptibility to this parasite. The results showed that BALB/c presented an enhancement of fibronectin during the course of infection when compared to their control group while the infected or non-infected C3H.He showed a decrease of this protein at end of the experiment. Laminin, on the other hand, remained unaltered in both strains. Also in both BALB/c and C3H.He mice the elastic and elaunin fibres remained unchanged while the oxytalan fibres decreased along the experiment. Ninety days after the infection C3H.He mice had recovered their capacity to produce oxytalan fibres. 相似文献
4.
Trine Ytrestøyl Harald Takle Jelena Kolarevic Sara Calabrese Gerrit Timmerhaus Bjørn O. Rosseland Hans C. Teien Tom O. Nilsen Sigurd O. Handeland Sigurd O. Stefansson Lars O. E. Ebbesson Bendik F. Terjesen 《Journal of the World Aquaculture Society》2020,51(2):373-392
Producing a larger post-smolt in recirculating aquaculture systems (RAS) could shorten the production time in sea cages and potentially reduce mortality. Knowledge of the biological requirements of post-smolts in closed-containment systems is however lacking. In the present study, the effects of salinity and water velocity on growth, survival, health, and welfare of Atlantic salmon reared in RAS were examined. Salmon smolts were stocked in three separate RAS with salinities of 12, 22, and 32‰ and subjected to high (1.0 body lengths per s−1) or low (0.3 body lengths second−1) water velocity. Growth performance, survival, welfare, and physiological stress responses were monitored until the fish reached a bodyweight of around 450 g. Growth rate was higher at lower salinity and higher water velocity generally had a positive effect on growth in all salinities. Feed conversion ratio was lower at 12‰ compared to the 22 and 32‰ when the fish were between 250 and 450 g. Higher mortality, elevated plasma cortisol levels, higher incidence of cataract, and a higher expression of stress-induced genes in the skin (iNOS, Muc5ac-like) indicated a negative effect of higher salinity on fish welfare. Male maturation was low (<1%), and not affected by salinity or water velocity. 相似文献
5.
Phytoparasitica - The present study was conducted in four central-southern Italian regions (Abruzzo, Campania, Molise, Puglia) in the years 2008 and 2016–2018, with the aim to verify in hilly... 相似文献
6.
Rebecca J. Kessler Shelley Rankin Sheri Young Kathleen O'Shea Maria Calabrese Amy Guldin Nicole Lipson Donna A. Oakley Urs Giger 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2010,39(1):29-38
Background: While screening programs have reduced the risk of infectious disease transmission by donors in human and veterinary blood banking, bacterial contamination of blood products has emerged as a major complication in human medicine. Objectives: To describe a Pseudomonas fluorescens (Pf)‐contaminated feline packed RBC (pRBC) unit and experimentally investigate Pf‐contaminated canine pRBCs. Methods: Canine pRBCs were inoculated with Pf‐rich pRBCs from the sentinel feline unit and stored at 4°C or 20°C for 72 hours. Aliquots from the pRBCs were serially evaluated by microscopy, culture, and a eubacterial 16S rRNA real‐time PCR assay. Results: One Pf‐contaminated feline unit turned black after 22 days of storage and was removed from the blood bank; a source was not found, and no other contaminated units were identified. Canine pRBCs spiked with 5 or 25 μL of the sentinel unit became culture‐ and/or 16S PCR‐positive at ≥8 hours at 20°C and 48 hours at 4°C and developed a color change at ≥24 hours. Sensitivity studies indicated that without incubation, inoculation of ≥100 μL Pf‐rich pRBCs was necessary for a positive 16S PCR test result. Conclusions: P. fluorescens grows in stored pRBCs slowly at 4°C and rapidly at 20°C. Screening of blood products for color change, estimating bacterial concentration with microscopy, and 16S PCR testing are simple and fast ways to detect bacteria in stored blood. Aseptic collection, temperature‐controlled storage, and regular visual monitoring of stored units is recommended. Discolored units should not be transfused, but examined for bacterial contamination or other blood product quality problems. 相似文献
7.
Guimarães KS Batista ZS Dias EL Guerra RM Costa AD Oliveira AS Calabrese KS Cardoso FO Souza CS do Vale TZ Gonçalves da Costa SC Abreu-Silva AL 《Veterinary parasitology》2005,131(3-4):305-309
Here, we describe the situation of canine visceral leishmaniasis in two villages of S?o José de Ribamar in Maranh?o State/Brazil, where human cases have been registered. Blood samples of 36 household crossbred dogs from Sergio Tamer village and 43 dogs from Quinta village were collected and the serum used for serological diagnosis. An Indirect Fluorescent Antibody Test (IFAT) and enzyme-linked immunosorbent assay (ELISA) were used to detect antibodies against Leishmania. The clinical examination showed that 25% of the canine population of Quinta presented a poor body condition and in 39%, ectoparasites (ticks and fleas) were detected. In both tests, serology revealed that 21% (9 out of 43) of the dogs presented antibodies against Leishmania (55% were asymptomatic and 45% were symptomatic). In the Vila Sérgio Tamer, 25% (9 out of 36) of the dogs were seropositive for Leishmania (66.67% were asymptomatic and 33.33% were symptomatic), 33% presented poor body condition, and 22% have ectoparasites. The clinical signs more frequent were skin lesions. The statistical analysis showed that there was no statistical difference (p>0.05) between the seropositivity of the dogs from the two villages. The same was observed when the clinical signs were compared (p>0.05). Both villages have favorable conditions to maintain the cycle of leishmaniasis. 相似文献
8.
Risk factors for Aujeszky's-disease seropositivity of swine herds of a region of northern Italy 总被引：3，自引：0，他引：3
Vaccination programs to control Aujeszky's-disease virus (ADV) using gE-deleted vaccines are being considered in several European countries. Knowledge of factors influencing ADV-seropositivity for vaccinated herds might contribute to the success of these programs. A multivariable analysis of ADV-seropositivity in 1248 swine herds (332 farrow-to-finish, 260 farrow-to-feeder and 656 finishing herds) in the Emilia-Romagna region of Italy revealed that (1) high pig density (number of pigs in a 6-km radius), (2) gilt purchasing, and (3) increased number of fattening pigs were risk factors for farrow-to-finish herds. In farrow-to-feeder herds, ADV-seropositivity was related to (1) increased number of breeders, (2) heavy-gilt purchasing, and (3) increased pig density. In finishing herds, (1) increased herd size was related to ADV-seropositivity, whereas (2) periodic rearing suspension was protective. 相似文献
9.
Amanda Mara Teles Leticia Prince Pereira Pontes Sulayne Janayna Araújo Guimares Ana Luiza Butarelli Gabriel Xavier Silva Flavia Raquel Fernandes do Nascimento Geusa Felipa de Barros Bezerra Carla Junqueira Moragas-Tellis Rui Miguel Gil da Costa Marcos Antonio Custdio Neto da Silva Fernando Almeida-Souza Ktia da Silva Calabrese Ana Paula Silva Azevedo-Santos Maria do Desterro Soares Brando Nascimento 《Marine drugs》2020,18(11)
Background: This study addresses the antitumoral properties of Penicillium purpurogenum isolated from a polluted lagoon in Northeastern Brazil. Methods: Ethyl Acetate Extracellular Extract (EAE) was used. The metabolites were studied using direct infusion mass spectrometry. The solid Ehrlich tumor model was used for antitumor activity. Female Swiss mice were divided into groups (n = 10/group) as follows: The negative control (CTL−), treated with a phosphate buffered solution; the positive control (CTL+), treated with cyclophosphamide (25 mg/kg); extract treatments at doses of 4, 20, and 100 mg/kg; animals without tumors or treatments (Sham); and animals without tumors treated with an intermediate dose (EAE20). All treatments were performed intraperitoneally, daily, for 15 days. Subsequently, the animals were euthanized, and the tumor, lymphoid organs, and serum were used for immunological, histological, and biochemical parameter evaluations. Results: The extract was rich in meroterpenoids. All doses significantly reduced tumor size, and the 20 and 100 mg/kg doses reduced tumor-associated inflammation and tumor necrosis. The extract also reduced the cellular infiltration of lymphoid organs and circulating TNF-α levels. The extract did not induce weight loss or renal and hepatic toxic changes. Conclusions: These results indicate that P. purpurogenum exhibits immunomodulatory and antitumor properties in vivo. Thus, fungal fermentation is a valid biotechnological approach to the production of antitumor agents. 相似文献
10.
Lycorine, an inhibitor of ascorbic acid biosynthesis, prevents the elicitation of KCN-insensitive respiration in aerated potato tuber slices. Ascorbic acid administration prevents the lycorine effect. Because KCN-insensitive respiration, which takes place during the aerobic incubation of potato tuber slices, specifically depends on the synthesis of new proteins, we suggest that ascorbic acid could be required to carry out a synthetic process. 相似文献