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排序方式: 共有98条查询结果,搜索用时 15 毫秒
21.
KR Arrigo DH Robinson DL Worthen RB Dunbar GR DiTullio M VanWoert MP Lizotte 《Science (New York, N.Y.)》1999,283(5400):365-367
Data from recent oceanographic cruises show that phytoplankton community structure in the Ross Sea is related to mixed layer depth. Diatoms dominate in highly stratified waters, whereas Phaeocystis antarctica assemblages dominate where waters are more deeply mixed. The drawdown of both carbon dioxide (CO2) and nitrate per mole of phosphate and the rate of new production by diatoms are much lower than that measured for P. antarctica. Consequently, the capacity of the biological community to draw down atmospheric CO2 and transport it to the deep ocean could diminish dramatically if predicted increases in upper ocean stratification due to climate warming should occur. 相似文献
22.
Rowena Hoare Sung‐Ju Jung Thao P. H. Ngo Kerry L. Bartie Kim D. Thompson Alexandra Adams 《Journal of fish diseases》2019,42(2):229-236
Flavobacterium psychrophilum is one of the most important pathogens affecting cultured rainbow trout (Oncorhynchus mykiss). Recent information from UK salmonid farms showed country‐wide distribution of genetically and serologically divergent clones, which has hampered the development of a vaccine for rainbow trout fry syndrome. The current study assessed the efficacy of an injectable polyvalent vaccine containing formalin‐inactivated F. psychrophilum in rainbow trout. The vaccine was formulated with an oil adjuvant (Montanide ISA 760VG) or formalin‐killed cells alone. Duplicate groups of trout (60 ± 13 g) were given phosphate‐buffered saline or vaccine formulated with Montanide by intra‐peritoneal (i.p.) injection and challenged by intra‐muscular (i.m.) injection with a homologous and a heterologous isolate of F. psychrophilum at 525 degree days post‐vaccination (dd pv). Significant protection was achieved in vaccinated fish (p = 0.0001, RPS 76% homologous, 88% heterologous). Efficacy of the adjuvanted vaccine was also demonstrated by heterologous challenge at 1155 dd pv resulting in 100% protection, whereas survival in the un‐adjuvanted group was not significantly different from control fish. Levels of specific antibody at 1155 dd pv, as measured by ELISA, were significantly higher in the fish vaccinated with adjuvant when compared with unvaccinated fish. 相似文献
23.
LFC Brito AD Barth NC Rawlings RE Wilde DH Crews Jr PS Mir JP Kastelic 《Reproduction in domestic animals》2007,42(5):502-508
The objective of the present study was to characterize changes in serum metabolic hormones concentrations from 20 weeks before to 20 weeks post-puberty in bulls and to investigate the associations of metabolic hormones concentrations with testicular development. Leptin concentrations increased from 16 weeks before puberty to 8 weeks post-puberty and insulin concentrations increased from puberty to 8 weeks post-puberty. Growth hormone concentrations decreased after 4 weeks post-puberty, whereas IGF-I concentrations increased from 8 weeks before puberty to 8 weeks post-puberty. During this period, testicular growth was accelerated and testosterone secretion increased substantially, without any significant changes in gonadotropin secretion. Monthly circulating concentrations of leptin, IGF-I and insulin accounted for 63% of the variation in scrotal circumference and 59% of the variation in paired testes volume. In conclusion, the secretion of metabolic hormones was not associated with changes in gonadotropins concentrations. Furthermore, the associations of leptin, IGF-I and insulin concentrations with testes size indicated that these hormones might be involved in a gonadotropin-independent mechanism regulating the testicular development in peripubertal bulls. 相似文献
24.
25.
Lenz G Davis RE Ngo VN Lam L George TC Wright GW Dave SS Zhao H Xu W Rosenwald A Ott G Muller-Hermelink HK Gascoyne RD Connors JM Rimsza LM Campo E Jaffe ES Delabie J Smeland EB Fisher RI Chan WC Staudt LM 《Science (New York, N.Y.)》2008,319(5870):1676-1679
Diffuse large B cell lymphoma (DLBCL) is the most common form of non-Hodgkin's lymphoma. In the least curable (ABC) subtype of DLBCL, survival of the malignant cells is dependent on constitutive activation of the nuclear factor-kappaB (NF-kappaB) signaling pathway. In normal B cells, antigen receptor-induced NF-kappaB activation requires CARD11, a cytoplasmic scaffolding protein. To determine whether CARD11 contributes to tumorigenesis, we sequenced the CARD11 gene in human DLBCL tumors. We detected missense mutations in 7 of 73 ABC DLBCL biopsies (9.6%), all within exons encoding the coiled-coil domain. Experimental introduction of CARD11 coiled-coil domain mutants into lymphoma cell lines resulted in constitutive NF-kappaB activation and enhanced NF-kappaB activity upon antigen receptor stimulation. These results demonstrate that CARD11 is a bona fide oncogenein DLBCL, providing a genetic rationale for the development of pharmacological inhibitors of the CARD11 pathway for DLBCL therapy. 相似文献
26.
Shinya Ishihara Fukuhiro Yamasaki Pham Hai Ninh Nguyen Cong Dinh Aisaku Arakawa Masaaki Taniguchi Ngo Thi Kim Cuc Satoshi Mikawa Masaru Takeya Kazuhiro Kikuchi 《Animal Science Journal》2020,91(1)
Although there are a number of Vietnamese native pig (VnP) populations, some are on the verge of extinction, and therefore adequate management and conservation are necessary. In this study, we conducted a field survey of VnP populations and analyzed interrelationships among their characteristics. We also established a relational database for management of field data on these populations. For data collection, we conducted interviews with farmers and visual inspection of 32 VnP populations in 22 provinces of Vietnam, as well as taking photographs of individual animals. Data on the characteristics of VnP populations were subjected to multiple correspondence analysis (MCA). For establishment of the database, normalization and table partitioning were performed to eliminate redundancy and ensure consistency of the collected data items. Passport data, characteristics data, and image data were collected from a total of 1,918 VnPs and entered as a normalized table. Upon MCA, most of the populations were not separated from each other, but the Mong Cai, O Lam, and Chu Prong populations were separated from the other populations. Thus, we have constructed a relational database from comprehensive information on the characteristics of VnP populations. 相似文献
27.
Vo TS Ngo DH Kim JA Ryu B Kim SK 《Journal of agricultural and food chemistry》2011,59(22):12193-12197
A peptide possessing antihypertensive activity was purified from Nile tilapia ( Oreochromis niloticus ) gelatin using alcalase, Pronase E, pepsin, and trypsin. Among them, the alcalase hydrolysate exhibited the highest angiotensin converting enzyme (ACE) inhibitory activity. Therefore, it was further analyzed, and a potent ACE inhibitory peptide of DPALATEPDPMPF (1382 Da) was separated and purified. In addition, the protective effect of the purified peptide against free radical-induced cellular and DNA damage in murine microglial cells (BV-2) was determined. These results suggest that the peptide isolated from Nile tilapia (O. niloticus) gelatin acts as a candidate against hypertension and oxidative stress and could be used in health-functional foods. 相似文献
28.
Histological examination was performed on the cervical spinal cord from 13 horses with chronic cervical compressive myelopathy of 4 to 29 months duration. Structural alterations were correlated with clinical features. At the level of compression, the spinal cord was grossly deformed. Histological alterations included nerve fibre swelling and degeneration, occasional spheroids, astrocytic gliosis, increased macrophage activity and increased perivascular collagen. Myelin degeneration or loss at the level of the compressive lesion was greatest in the ventral and lateral funiculi and less consistently present in the dorsal funiculi. Asymmetry of lesions in the dorsal funiculi was associated with asymmetry of clinical signs in 5 horses. Histological alterations in areas of Wallerian degeneration were similar to that at the level of spinal cord compression, except that perivascular collagen was not increased. Wallerian degeneration was present cranial to the compressed site in the superficial portions of the lateral funiculi and in the middle of the dorsal funiculi. Caudal to the compressed site it was present in the ventral funiculi adjacent to the ventral median fissure and in the middle of the lateral funiculi. Deformation of the spinal cord did not correlate with the severity or duration of clinical signs but was positively correlated with the amount of perivascular collagen increase. The amount of nerve fibre swelling was not correlated with the severity of clinical signs but was negatively correlated with their duration. A rapid loss of nerve fibres apparently occurred early in the course of compression, since there was a marked decrease in the amount of nerve fibre swelling and Marchi stained degenerating myelin with increasing clinical duration.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
29.
随着养猪业不断发展,养猪生产者一直在努力寻求营养途径,改善猪的生产性能和提高利润。其途径之一是补充日粮脂肪以提高母猪的泌乳量,减少哺乳期体重损失。哺乳母猪的采食量可能不足以满足泌乳需要,导致母猪处于能量负平衡并动用体贮存。泌乳期体脂肪和体蛋白的损失能够引起繁殖功能障碍,如异常发情,发情推迟,延长断奶至发情间隔,降低受胎率,增加淘汰率。妊娠后期和泌乳期补充日粮脂肪,能增加母猪的泌乳量,提高初乳和常乳中脂肪含量,增加仔猪成活率和缩短母猪断乳至配种间隔时间。Gunther(1996)报道,母猪饲料中补充8 %的两种… 相似文献
30.
In this study, flax shive (FS) and extracted flax shive (EFS) were fully characterized. The results showed that EFS presented lower noncellulose content, smaller porous tunnels and better thermal stability than FS. The 5 % weight loss temperature of EFS was over 200 °C, which can meet the requirements of the processing conditions for the natural fiber reinforced polymer composites. Consequently, the flax shive and extracted flax shive reinforced PP composites were prepared and characterized. It was found that the thermal stability of EFS/PP composites was better than that of FS/PP composites, and both FS and EFS behaved as nucleation agents, which could accelerate the crystallization process of PP in the composites. Mechanical test showed that EFS could be used as a reinforcing material for PP composite when compatibilizer was applied. The flexural strength and modulus of the composites containing 30 % EFS were about 8 % and 100 % higher than that of pure polypropylene, respectively. 相似文献