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91.
Karen L. Klomparens Maureen A. Petersen Donald C. Ramsdell William G. Chaney 《Microscopy research and technique》1986,4(1):47-54
Scanning electron microscopy autoradiography (SEM-AR) in conjunction with light microscope autoradiography (LM-AR) was used to follow the movement of 125I-labeled blueberry shoestring virus (BBSSV) through its aphid vector Illinoia pepperi with varying acquisition access periods (AAP). At 6 hr AAP, the virus had reached the stomach; at 12 hr AAP, it had reached the anterior of the intestines, and after 48 hr, AAP was present throughout the aphid. SEM-AR using backscatter electron detection proved very useful because the sample bulk resulted in a shortened exposure time compared to LM sections, correlation of the autoradiograms could be made with fine structure, preparing large numbers of samples was easy, and examining whole longitudinal sections of aphids at low magnification with a clearly visible marker was possible. Limitations were mostly attributed to sample preparation and, in some cases, were easily remedied. 相似文献
92.
Follicles > or = 5 mm were ablated in pony mares by a transvaginal ultrasound-guided technique on Day 10 (ovulation = Day 0). Follicle emergence (at 15 mm, experiment 1; at 6 mm, experiment 2) and development of the new wave was monitored by transrectal ultrasound. Deviation was defined as the beginning of a marked difference in growth rates between the two largest follicles. In experiment 1, mares were grouped (n = 4 per group) into controls, ablation-controls (ablations at Day 10 only), and a two-follicle model (periodic ablation sessions so that only the two largest follicles developed). There were no significant indications that the two-follicle model altered follicle diameters, growth rates, or time intervals of the two retained follicles at or between events (follicle emergence, deviation, and ovulation). In experiment 2, the two-follicle model (n = 14) was used for follicle and hormonal characterization and hypothesis testing, without the tedious and error-prone necessity for tracking many (e.g., 20) individual follicles. The future dominant follicle emerged a mean of 1 day earlier (p < 0.008) than the future subordinate follicle, the growth rates for the two follicles between emergence and deviation (6 days later) did not differ, and the dominant follicle was larger at the beginning of deviation (23.1 +/- 0.8 mm versus 19.6 +/- 0.9 mm; p < 0.0001). Mean FSH and LH concentrations increased (p < 0.05) concomitantly from emergence of the future dominant follicle and peaked 3 days later when the follicle was a mean of 13 mm. Thereafter, the two hormones disassociated until ovulation: FSH decreased and LH increased. Results supported the hypothesis that the future dominant follicle has an early size advantage over future subordinate follicles and indicated that the advantage was present as early as 6 days before deviation. 相似文献
93.
EL Luk''ianova 《Canadian Metallurgical Quarterly》1997,33(6):662-668
INTRODUCTION: The most common fat-suppressed sequence used to study skeletal conditions is the STIR sequence which has shown high sensitivity in the detection of skeletal lesions and whose main drawback is its long acquisition time. Currently, Turbo-STIR (T-STIR) sequences can shorten the acquisition time. The purpose of this study was therefore to compare the conventional STIR sequence with the new T-STIR sequence in the study of skeletal conditions to compare their diagnostic yield. MATERIAL AND METHODS: Twenty patients with different types of skeletal lesions were examined. MR examinations were performed with a Philips Gyroscan S15/ACS II unit (1.5 T). All the patients underwent a STIR sequence (TR/TE = 1500/20, TI = 180 ms, matrix = 204 x 256, NEX = 2, slice thickness = 5 mm, acquisition time = 9 min 24 s) and a T-STIR sequence (TR/TE = 1500/20, TI = 180 ms, matrix = 204 x 256, NEX = 2, slice thickness = 5 mm, TFL = 3, acquisition time = 3 min 33 s). The images were evaluated by measuring both quantitative parameters--percent contrast (%C), contrast to noise ratio (C/N), signal to noise ratio (S/N)--and qualitative parameters--lesion conspicuity, margins and extension, motion artifacts, image quality. RESULTS: The only statistically significant difference between the two sequences was image quality, which was superior in the conventional STIR sequence (p < .05). No statistically significant difference was demonstrated with the quantitative evaluation. DISCUSSION: In this study, T-STIR sequences were performed with low-high acquisition profile to acquire an actual echo time of 20 ms which permits to obtain optimal S/N with good spatial resolution. Therefore, T-STIR sequences with low-high acquisition profile provides better results than T-STIR sequences with linear acquisition profile which permits to obtain an actual echo time of 40 ms. CONCLUSION: This work shows that T-STIR sequences can replace conventional STIR sequences in the study of skeletal conditions reducing the acquisition time by 60%. This result can be obtained only by an accurate optimization of acquisition parameters. 相似文献
94.
The aril of the plant Myristica fragrans is one of the most broadly used spices in Moroccan gastronomy. This research demonstrated its antimicrobial activity against both gram-positive and gram-negative bacterial species. Likewise, its toxicity was investigated on Swiss albino mice. Mice were treated orally with 0.003 and 0.3 mg/day during 7 days. Plasmatic markers and antioxidant defense systems were assessed and histological alterations evaluated. Our results showed a significant increase in creatine phosphokinase level. The microscopic evaluation showed that mace induces morphological perturbation in mice's liver. The results also showed an inhibitory effect of glyceraldehyde 3-phosphate dehydrogenase and an important increase in the level of thiobarbituric acid reactive substances, succinate dehydrogenase activities and no change in catalase activities. All of these results show that M. fragrans at 0.3 mg/g in mice affects energy metabolism and oxidative stress.
Mace can be used as a natural antioxidant and preservative in the food industry to increase the shelf life of foodstuffs. 相似文献
PRACTICAL APPLICATIONS
Mace can be used as a natural antioxidant and preservative in the food industry to increase the shelf life of foodstuffs. 相似文献
95.
M Mori PG Beatty M Graves KM Boucher EL Milford 《Canadian Metallurgical Quarterly》1997,64(7):1017-1027
BACKGROUND: As of May 1, 1995, the National Marrow Donor Program had a donor registry consisting of over 1.35 million HLA-typed volunteers recruited from most major cities and states in the United States. This registry represents the largest single HLA-typed pool of normal individuals in the world. METHODS: We analyzed the HLA-A, -B, -DR locus phenotypes of the National Marrow Donor Program donors in order to estimate gene and haplotype frequencies for major racial groups of the United States: Caucasian American, Asian American, African American, Latin American, and Native American. The large size of the database allowed us to calculate the frequencies of relatively rare antigens and haplotypes with more accuracy than previous studies. RESULTS: We observed 89,522 distinguishable HLA-A, -B phenotypes in 1,351,260 HLA-A, -B-typed donors and 302,867 distinguishable HLA-A, -B, -DR phenotypes in 406,503 HLA-A, -B, -DR-typed donors. Gene and haplotype frequencies differed remarkably among the five racial groups, with African Americans and Asian Americans having a large number of haplotypes that were specific to their racial groups, whereas Caucasian Americans, Latin Americans, and Native Americans shared a number of common haplotypes. CONCLUSIONS: These data represent an important resource for investigators in the fields of transplantation and population genetics. The gene and haplotype frequencies can be used to aid clinicians in advising patients about the probability of finding a match within a specific ethnic group, or to determine donor recruitment goals and strategies. The information is also a valuable resource for individuals who are interested in population genetics, selection and evolution of polymorphic human genes, and HLA-disease association. 相似文献
96.
97.
98.
A proposed method to reconstruct the three‐dimensional dispersion profile of polymeric fibres based on variable wavelength interferometry 下载免费PDF全文
In this paper, we suggest a modification to the conventional variable wavelength interferometry. This modification allowed us to calculate the dispersion curve of each point inside polymeric fibres instead of calculating the mean dispersion of these fibres. This modified mathematical treatment was used to calculate the three‐dimensional dispersion profile of isotactic polypropylene fibres suffering from necking deformation. The different steps of calculating the three‐dimensional dispersion profile of the fibre were demonstrated. The application of this modified method revealed the variation of the fibre material dispersion before, inside and after the necking region. In addition, the birefringence profile of the necked isotactic polypropylene was determined using the proposed mathematical treatment. This allowed us to diagnose the interaction of the incident waves with necked polypropylene fibres, which gives extensive information on the orientation of the molecular chains during the formation of the necking phenomenon. 相似文献
99.
Stuffed grape vine leaves, dolma is a well-liked Turkish dish, common to Mediterranean diets. Moisture, ash, energy, protein, fat, carbohydrate, calcium, sodium, iron, β-carotene (vitamin A), vitamin C analyses were conducted to determine the nutritional value of dolma. β-carotene level per 100 g serving of dolma (1041 IU) supplies 20.82% of the USRDA (5000 IU) and an INQ (Index of Nutritional Quality) for vitamin A of 2.54. Although the fat content and INQ for fat were found to be high in dolma, it can still be considered a healthy choice due to the type of oil used, namely olive oil, which has been shown to have beneficial effects on health. 相似文献
100.
Broadhurst CL Chaney RL Angle JS Maugel TK Erbe EF Murphy CA 《Environmental science & technology》2004,38(21):5797-5802
We have developed commercially viable phytoremediation/phytomining technologies employing Alyssum Ni-hyperaccumulator species to quantitatively extract Ni from soils. The majority of Ni is stored either in Alyssum leaf epidermal cell vacuoles or in the basal portions only of the numerous stellate trichomes. Here, we report simultaneous and region-specific localization of high levels of Ni, Mn, and Ca within Alyssum trichomes as determined by scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDX). Plants were grown in high Ni soil, achieving up to 48 400 microg g(-1) Ni in total leaf concentration; however, Ca and Mn were not enriched in the experimental soils. The region-specific localization of hyperaccumulated Ca, Mn, and Ni occurred in three soil types, five Alyssum species/ecotypes, and over a wide range of soil Ni concentrations. The metal concentration in the trichome basal compartment was approximately 15-20% dry weight, the highest ever reported for healthy vascular plant tissue. 相似文献