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111.
A new ankylosaurid (Ankylosauria: Dinosauria), Ziapelta sanjuanensis, gen. et sp. nov., is based on a complete skull, an incomplete first cervical half ring, a possible fragment of the second cervical half ring, and additional fragmentary osteoderms. The holotype specimen is from the Upper Cretaceous (Upper Campanian, Kirtlandian Land-Vertebrate Age) Kirtland Formation (De-na-zin Member) at Hunter Wash, San Juan Basin, in northwestern New Mexico, USA. Diagnostic characters of Ziapelta include: a large, prominent triangular median nasal caputegulum; a mixture of flat and bulbous frontonasal caputegulae; ventrolaterally oriented squamosal horns with a sharp, prominent dorsal keel; and the ventral surface of basicranium with three prominent anteroposteriorly oriented fossae. A phylogenetic analysis suggests that Ziapelta is not closely related to the other ankylosaurid from the De-na-zin Member, Nodocephalosaurus, but allies it to the northern North American ankylosaurids Ankylosaurus, Anodontosaurus, Euoplocephalus, Dyoplosaurus, and Scolosaurus.  相似文献   
112.
Rift Valley fever (RVF) is an important mosquito-borne viral zoonosis in Africa and the Middle East that causes human deaths and significant economic losses due to huge incidences of death and abortion among infected livestock. Outbreaks of RVF are sporadic and associated with both seasonal and socioeconomic effects. Here we propose an almost periodic three-patch model to investigate the transmission dynamics of RVF virus (RVFV) among ruminants with spatial movements. Our findings indicate that, in Northeastern Africa, human activities, including those associated with the Eid al Adha feast, along with a combination of climatic factors such as rainfall level and hydrological variations, contribute to the transmission and dispersal of the disease pathogen. Moreover, sporadic outbreaks may occur when the two events occur together: 1) abundant livestock are recruited into areas at risk from RVF due to the demand for the religious festival and 2) abundant numbers of mosquitoes emerge. These two factors have been shown to have impacts on the severity of RVF outbreaks. Our numerical results present the transmission dynamics of the disease pathogen over both short and long periods of time, particularly during the festival time. Further, we investigate the impact on patterns of disease outbreaks in each patch brought by festival- and seasonal-driven factors, such as the number of livestock imported daily, the animal transportation speed from patch to patch, and the death rate induced by ceremonial sacrifices. In addition, our simulations show that when the time for festival preparation starts earlier than usual, the risk of massive disease outbreaks rises, particularly in patch 3 (the place where the religious ceremony will be held).  相似文献   
113.
To facilitate dynamic imaging of neural crest (NC) lineages and discrimination of individual cells in the enteric nervous system (ENS) where close juxtaposition often complicates viewing, we generated a mouse BAC transgenic line that drives a Histone2BVenus (H2BVenus) reporter from Sox10 regulatory regions. This strategy does not alter the endogenous Sox10 locus and thus facilitates analysis of normal NC development. Our Sox10-H2BVenus BAC transgene exhibits temporal, spatial, and cell-type specific expression that reflects endogenous Sox10 patterns. Individual cells exhibiting nuclear-localized fluorescence of the H2BVenus reporter are readily visualized in both fixed and living tissue and are amenable to isolation by fluorescence activated cell sorting (FACS). FACS-isolated H2BVenus+ enteric NC-derived progenitors (ENPs) exhibit multipotency, readily form neurospheres, self-renew in vitro and express a variety of stem cell genes. Dynamic live imaging as H2BVenus+ ENPs migrate down the fetal gut reveals cell fragmentation suggesting that apoptosis occurs at a low frequency during normal development of the ENS. Confocal imaging both during population of the fetal intestine and in postnatal gut muscle strips revealed differential expression between individual cells consistent with down-regulation of the transgene as progression towards non-glial fates occurs. The expression of the Sox10-H2BVenus transgene in multiple regions of the peripheral nervous system will facilitate future studies of NC lineage segregation as this tool is expressed in early NC progenitors and maintained in enteric glia.  相似文献   
114.
Long interspersed nuclear element 1 (LINE-1; L1) retrotransposons are the most common retroelements in mammalian genomes. Unlike individual families of endogenous retroviruses (ERVs), they have remained active throughout the mammalian radiation and are responsible for most of the retroelement movement and much genome rearrangement within mammals. They can be viewed as occupying a substantial niche within mammalian genomes. Our previous demonstration that L1s and B1 short interspersed nuclear elements (SINEs) are inactive in a group of South American rodents led us to ask if other elements have amplified to fill the empty niche. We identified a novel and highly active family of ERVs (mysTR). To determine whether loss of L1 activity was correlated with expansion of mysTR, we examined mysTR activity in four South American rodent species that have lost L1 and B1 activity and four sister species with active L1s. The copy number of recent mysTR insertions was extremely high, with an average of 4,200 copies per genome. High copy numbers exist in both L1-active and L1-extinct species, so the mysTR expansion appears to have preceded the loss of both SINE and L1 activity rather than to have filled an empty niche created by their loss. It may be coincidental that two unusual genomic events--loss of L1 activity and massive expansion of an ERV family--occur in the same group of mammals. Alternatively, it is possible that this large ERV expansion set the stage for L1 extinction.  相似文献   
115.
116.
Nitric oxide dietary supplements are popular within the sport community. Our recent work involving the oral intake of 2-nitrooxy ethyl 2-amino 3-methylbutanoate demonstrated an approximately 6.7% increase in circulating nitrate/nitrite. However, no measures of exercise performance were obtained. The present study used a topical form of this molecule to determine the impact on exercise performance and blood nitrate/nitrite. Fourteen resistance trained men (24 ± 1 years old) reported to the laboratory on 2 occasions to undergo exercise testing, which consisted of arm curl isometric force and muscular endurance (3 sets to fatigue using 80, 65, and 50% of 1 repetition maximum [1RM]: total of 9 sets). The gel (2-nitrooxy ethyl 2-amino 3-methylbutanoate; mixed in tea tree oil) or placebo (tea tree oil) was applied topically by the subjects for 7 days before each test day, with 7-10 days separating the randomly ordered conditions. Blood samples, arm circumference, and perceived "muscle pump" were taken before and immediately after exercise on both test days. The heart rate and perceived exertion were measured after each set. No statistically significant differences were noted between conditions for performance variables (p > 0.05). However, when using a load of 50% of 1RM, 6.2% more repetitions were performed when using the gel as compared with when using the placebo; 19.9% more repetitions were performed by 8 subjects noted to be "responders" to gel treatment. Blood lactate and muscle pump significantly increased with exercise (p < 0.0001) but were not different between conditions (p > 0.05). Minimal change was noted in nitrate/nitrite, and the heart rate and perceived exertion were nearly identical between conditions (p > 0.05). These findings indicate that 2-nitrooxy ethyl 2-amino 3-methylbutanoate gel has a modest (6.2%), nonstatistically significant effect on exercise performance, in particular when using a load of 50% 1RM-with greater benefit noted in selected individuals. Studies inclusive of a larger sample size are needed to extend these initial findings.  相似文献   
117.
A series of benzimidazoles (4) was synthesized and evaluated in vitro as potent and selective NPY Y1 receptor antagonists. Substitution of the piperidine nitrogen of 4 with appropriate R groups resulted in compounds with more than 80-fold higher affinity at the Y receptor compared to the parent compound 5 (R = H). The most potent benzimidazole in this series was 21 (Ki = 0.052 nM).  相似文献   
118.
We study a reaction-diffusion-advection model for two ecologically equivalent competitors with different dispersal strategies inhabiting a spatially heterogeneous environment. The competitors represent different phenotypes of the same species. One is assumed to disperse by simple diffusion, the other by diffusion together with directed movement toward more favorable environments. We show that under suitable conditions on the underlying spatial domain, the competitor that moves toward more favorable environments may have a competitive advantage even if it diffuses more rapidly than the other competitor. This is in contrast with the case in which both competitors disperse by pure diffusion, where the competitor that diffuses more slowly always has the advantage. We determine competitive advantage by examining the invasibility, i.e. stability or instability, of steady states with only one competitor present. The mathematical approach is a perturbation analysis of principal eigenvalues.  相似文献   
119.
Rice powder extract (RPE) from black and brown rice (Oryza sativa L. indica) improves hepatic lipid accumulation in obese and diabetic model mice via peroxisomal fatty acid oxidation. RPE showed PPARα agonistic activity which did not differ between black and brown RPE despite a higher anthocyanin content in black RPE.  相似文献   
120.
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