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991.
Anuran (Rana) and urodele (Ambystoma) amphibian eggs were subjected to prolonged unnatural orientations in relation to gravity. In some cases eggs were rotated 90°, while in other instances eggs were rotated 180° (complete inversion). Alterations in the pigmentation pattern, cleavage pattern, and site of involution were observed. Despite these unnatural orientations to gravity, the morphogenesis of axial structures was frequently normal. Reorganization of the egg cytoplasm apparently takes place after the unnatural orientation. Rather than being localized in a fixed position in the egg (e.g., the egg cortex), the determinants for the pattern of early embryogenesis are probably located in that portion of the cytoplasm (e.g., “internal” cytoplasm) that orients to gravity. 相似文献
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Lateral root development in onion is accompanied by a variety of anatomical and permeability changes in some cells of the adventitious root. The endodermal Casparian band of the parent root is disrupted early in the development of the lateral but later extends so as to be continuous with the developing Casparian band of the new root. The lateral root emerges through a longitudinal split in the adventitious root exodermis and epidermis. Following this, the cell walls and intercellular air spaces adjacent to the lateral become incrusted with suberin and a small amount of lignin, forming a collar of modified tissue around the lateral. Subsequent radial expansion of the lateral distorts the adjacent cells of the adventitious root and forces a tight association between it and the lateral. The apoplastic permeability of lateral/parent root junctions was tested using Cellufluor, an apoplastic fluorescent dye which binds to cellulose. Prior to lateral root emergence, no dye enters the parent root cortex due to the Casparian band of the exodermis. Immediately after emergence, dye often penetrates through the break in the exodermal Casparian band and diffuses into the first cortical cell layer. However, when the collar of suberized cells develops (two days after lateral root emergence), movement of the dye into an undisturbed adventitious root is usually prevented (i.e., in 77% of the cases examined). In contrast, only 17% of the root systems which were transplanted just prior to treatment excluded the dye. This indicates that the apoplastic seals around the laterals are sensitive to movement and we recommend that only undisturbed root systems be used for permeability studies. 相似文献
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Robert Belknap Steve Weis Andrew Brookens Kit Yee Au-Yeung Greg Moon Lorenzo DiCarlo Randall Reves 《PloS one》2013,8(1)
Poor adherence to tuberculosis (TB) treatment hinders the individual’s recovery and threatens public health. Currently, directly observed therapy (DOT) is the standard of care; however, high sustaining costs limit its availability, creating a need for more practical adherence confirmation methods. Techniques such as video monitoring and devices to time-register the opening of pill bottles are unable to confirm actual medication ingestions. A novel approach developed by Proteus Digital Health, Inc. consists of an ingestible sensor and an on-body wearable sensor; together, they electronically confirm unique ingestions and record the date/time of the ingestion. A feasibility study using an early prototype was conducted in active TB patients to determine the system’s accuracy and safety in confirming co-ingestion of TB medications with sensors. Thirty patients completed 10 DOT visits and 1,080 co-ingestion events; the system showed 95.0% (95% CI 93.5–96.2%) positive detection accuracy, defined as the number of detected sensors divided by the number of transmission capable sensors administered. The specificity was 99.7% [95% CI 99.2–99.9%] based on three false signals recorded by receivers. The system’s identification accuracy, defined as the number of correctly identified ingestible sensors divided by the number of sensors detected, was 100%. Of 11 adverse events, four were deemed related or possibly related to the device; three mild skin rashes and one complaint of nausea. The system’s positive detection accuracy was not affected by the subjects’ Body Mass Index (p = 0.7309). Study results suggest the system is capable of correctly identifying ingestible sensors with high accuracy, poses a low risk to users, and may have high patient acceptance. The system has the potential to confirm medication specific treatment compliance on a dose-by-dose basis. When coupled with mobile technology, the system could allow wirelessly observed therapy (WOT) for monitoring TB treatment as a replacement for DOT. 相似文献
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Prostaglandin F (PGF) levels in endometriotic tissue in vitro have been shown to be higher than the levels in healthy ovarian tissue and uterine endometrium. The results of a study of nine women with endometriosis support this finding and suggest that prostaglandins have an important role in the pathogenesis of the symptoms and infertility in such women. 相似文献