共查询到20条相似文献,搜索用时 31 毫秒
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Postoperative bronchopleural fistulas may be demonstrated quickly and safely by inhalation of nebulized 99mTc-albumin, or other similar radiopharmaceuticals. Posterior scintiphotographs of the distribution of the inhaled radioactive material are obtained with the gammaray scintillation camera while the patient is in the upright and lateral decubitus positions. The observation of radioactive material in the pleural cavity indicates an abnormal communication.The radiation-absorbed doses for lung and total body are well within acceptable limits when a 99mTc tag is used. About 15 minutes are required to complete this relatively safe diagnostic test. 相似文献
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W. P. D. Logan 《BMJ (Clinical research ed.)》1956,1(4969):722-725
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Epithelia form the building blocks of many tissue and organ types. Epithelial cells often form a contiguous 2-dimensional sheet that is held together by strong adhesions. The mechanical properties conferred by these adhesions allow the cells to undergo dramatic three-dimensional morphogenetic movements while maintaining cell–cell contacts during embryogenesis and post-embryonic development. The Drosophila Folded gastrulation pathway triggers epithelial cell shape changes that drive gastrulation and tissue folding and is one of the most extensively studied examples of epithelial morphogenesis. This pathway has yielded key insights into the signaling mechanisms and cellular machinery involved in epithelial remodeling. In this review, we discuss principles of morphogenesis and signaling that have been discovered through genetic and cell biological examination of this pathway. We also consider various regulatory mechanisms and the system?s relevance to mammalian development. We propose future directions that will continue to broaden our knowledge of morphogenesis across taxa. 相似文献
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Matthew D. Ettleson Ava Raine Alice Batistuzzo Samuel P. Batista Elizabeth McAninch Maria Cristina T.V. Teixeira Jacqueline Jonklaas Neda Laiteerapong Miriam O. Ribeiro Antonio C. Bianco 《Endocrine practice》2022,28(3):257-264
ObjectivePatient-centered studies have shown that several patients on thyroid hormone replacement therapy for hypothyroidism exhibit persistent symptoms, including “brain fog.” Here, we aimed to determine which of these specific symptoms are associated with brain fog, identify patient-reported factors that modify these symptoms, and identify patient concerns related to brain fog not included in thyroid-specific questionnaires.MethodsA survey on brain fog symptoms adapted from thyroid-specific patient-reported outcome was distributed online. Textual data analysis was performed to identify common areas of concern from open-ended survey responses.ResultsA total of 5170 participants reporting brain fog while being treated for hypothyroidism were included in the analysis. Of these, 2409 (46.6%) participants reported symptom onset prior to the diagnosis of hypothyroidism, and 4096 (79.2%) participants experienced brain fog symptoms frequently. Of the symptoms listed, participants associated fatigue and forgetfulness most frequently with brain fog. More rest was the most common factor provided for improving symptoms. The textual data analysis identified areas of concern that are not often included in thyroid-specific quality of life questionnaires, including a focus on the diagnosis of hypothyroidism, the types and doses of medications, and the patient-doctor relationship.ConclusionBrain fog in patients treated for hypothyroidism was associated most frequently with fatigue and cognitive symptoms. Several additional areas of patient concern were found to be associated with brain fog, which are not typically addressed in thyroid-specific questionnaires. 相似文献
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Fog depositional patterns on the needles of three conifers wereexamined experimentally using ultrasonically generated fog dropletscontaining a dilute fluorescent dye. Fluorescence microscopyanalysis of deposition rates and patterns revealed that themechanism of inertial impaction was of little importance underthe imposed conditions. Gravitational sedimentation and diffusionaltransport may be important for Abies balsamea, but surface activemechanisms probably dominate for Picea rubens and, possibly,Pinus strobus. In young physiologically active needles of Picearubens most of the fog was deposited on the epicuticular waxeswhich occlude epistomatal chambers. This non-random depositionalpattern is discussed with reference to the sensitivity of Picearubens to acidic fogs. Key words: Wet aerosol, air pollution, fluorescence microscopy 相似文献
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With the explosive growth of the world's population and the rapid increase in industrial water consumption,the world's water supply has fallen into crisis.The s... 相似文献
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A method to achieve controlled ice nucleation during the freeze-drying process using an ice fog technique was demonstrated
in an earlier report. However, the time required for nucleation was about 5 min, even though only one shelf was used, which
resulted in Ostwald ripening (annealing) in some of the vials that nucleated earlier than the others. As a result, the ice
structure was not optimally uniform in all the vials. The objective of the present study is to introduce a simple variation
of the ice fog method whereby a reduced pressure in the chamber is utilized to allow more rapid and uniform freezing which
is also potentially easier to scale up. Experiments were conducted on a lab scale freeze dryer with sucrose as model compound
at different concentration, product load, and fill volume. Product resistance during primary drying was measured using manometric
temperature measurement. Specific surface area of the freeze-dried cake was also determined. No difference was observed either
in average product resistance or specific surface area for the different experimental conditions studied, indicating that
with use of the reduced pressure ice fog technique, the solutions nucleated at very nearly the same temperature (−10°C). The
striking feature of the “Reduced Pressure Ice Fog Technique” is the rapid ice nucleation (less than a minute) under conditions
where the earlier procedure required about 5 min; hence, effects of variable Ostwald ripening were not an issue. 相似文献
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Holly A. Ewing Kathleen C. Weathers Pamela H. Templer Todd E. Dawson Mary K. Firestone Amanda M. Elliott Vanessa K. S. Boukili 《Ecosystems》2009,12(3):417-433
Fog is thought to influence ecological function in coastal forests worldwide, yet few data are available that illuminate the
mechanisms underlying this influence. In a California redwood forest we measured water and nitrogen (N) fluxes from horizontally
moving fog and vertically delivered rain as well as redwood tree function. The spatial heterogeneity of water and N fluxes,
water availability, tree water use, and canopy N processing varied greatly across seasons. Water and N fluxes to soil (annual
average of 98% and 89%, respectively) across the whole forest occurred primarily in the rain season and was relatively even
across the whole forest. In contrast, below-canopy flux of fog water and N declined exponentially from the windward edge to
the forest interior. Following large fog events, soil moisture was greater at the windward edge than anywhere else in the
forest. Physiological activity in redwoods reflected these differences in inputs across seasons: tree physiological responses
did not vary spatially in the rain season, but in the fog season, water use was greater, yet water stress was less, in trees
at the windward edge of the forest versus the interior. In both seasons, vertical passage through the forest changed the amount
of water and form and concentration of N, revealing the role of the tree canopy in processing atmospheric inputs. Although
total fog water inputs were comparatively small, they may have important ecosystem functions, including relief of canopy water
stress and, where there is fog drip, functional coupling of above- and belowground processes.
Author Contributions We make no distinction in effort and contribution between the first and second authors or between the third and fourth authors.
HAE and KCW were responsible for project design, oversight, data analysis, synthesis, and writing. PHT analyzed N samples
and contributed significantly to interpretation of data. TED established the initial tree physiology study site, provided
and analyzed the data on tree physiology, and contributed to the synthesis of these data. MKF first identified the lack of
connection between inputs and microbial processing and catalyzed synthesis regarding belowground processing. AME created figures,
performed field and laboratory work, and was database manager. VKSB collected field samples and carried out the litterfall
study. All authors edited the paper. 相似文献
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西双版纳地区附生与非附生植物叶片对雾水的吸收 总被引:3,自引:0,他引:3
采用蒸馏水喷雾(模拟雾)法,测定了西双版纳地区干季中10种附生植物和非附生植物叶片水势(Φ)、相对含水量(RWC)和吸水量的变化,探讨了不同类型植物叶片的吸收雾水的能力.结果表明,随喷雾时间的延长,植物叶片Φ、RWC和吸水量均升高,说明附生植物和非附生植物叶片都能吸收雾水,但附生植物叶片吸水后Φ升高明显快于非附生植物.附生植物附着实蕨和爬树龙叶片吸水快、RWC变化大,表明其叶片吸收雾水的能力强;贝母兰和掌唇兰叶片吸水能力低于非附生植物中的穿鞘花和野靛稞,但高于其它4种非附生植物.傍晚雾生之前附生植物叶片Φ显著低于清晨,表明夜间附生植物叶片吸收了雾水;而非附生植物傍晚叶片Φ与清晨水势差异不显著,夜间几乎不吸收雾水.除贝母兰外,附生植物叶生物量分数高于非附生植物,利于其吸收雾水.由于西双版纳地区干季多雾,该区植物叶片最低水势均在-0.8 MPa以上,水分胁迫不严重. 相似文献