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1.
The direct excision of glabellar frown lines is a method that is not new, but neither has it been well evaluated. This paper describes the method, discusses the reason for the problem, and suggests why this method should have long-lasting results. Several examples of the scars are demonstrated. In selected patients, this may be a reasonable alternative to the myriad surgical possibilities in our quest for a solution to this problem.  相似文献   

2.
The objective of this study was to evaluate the efficacy and safety of botulinum toxin type A for the treatment of glabellar lines. Patients with moderate or severe glabellar lines at maximal frown received intramuscular injections of placebo or 20 U of botulinum toxin type A (Botox; Allergan, Inc., Irvine, Calif.) distributed among five injection sites (one in the procerus muscle and two in each corrugator supercilii). Follow-up assessments were performed at 7, 30, 60, 90, and 120 days after injections. Efficacy measures were the physician's rating of glabellar line severity at maximal frown and at rest (none, mild, moderate, or severe) and the patient's global assessment of changes in glabellar lines, from +4 (100 percent better) to -4 (100 percent worse). A total of 273 patients were enrolled (botulinum toxin, 202 patients; placebo, 71 patients). All except five patients (botulinum toxin, two patients; placebo, three patients) completed the study. For the physician's rating at maximal frown, the responder rate (percentage of patients with severity ratings of none or mild in follow-up evaluations) for the botulinum toxin group peaked at 77 percent at day 30 and was significantly greater than that for the placebo group at every follow-up visit (p < 0.001). For the patient's assessment, the responder rate (percentage of patients with scores of +2 or more) for the botulinum toxin group peaked at 89 percent at day 30 and was significantly greater than that for the placebo group at every follow-up visit (p < 0.001). Rates of adverse events were similar for the two groups. The only adverse event with an incidence of >/=5 percent was headache (botulinum toxin, 11 percent; placebo, 20 percent). The incidence of blepharoptosis was 1 percent for the botulinum toxin group. Botulinum toxin type A was remarkably safe and effective in reducing glabellar lines.  相似文献   

3.
For nearly 100 years, aesthetic improvement of the aging face has included surgical elevation of the brow. Early attempts to correct brow ptosis were largely unsuccessful. Recognizing the need to modify the frown muscles heralded the achievement of results previously unobtainable. Within the past decade, the minimal incision approach to brow lifting afforded with the endoscope radically changed surgical options in forehead rejuvenation. Further advances have added to these options and have provided a palette of alternatives in aesthetic correction of the upper one-third of the aging face.  相似文献   

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Matarasso A  Hutchinson OH 《Plastic and reconstructive surgery》2000,106(3):687-94; discussion 695-6
The traditional reason for performing aesthetic surgery in the forehead and brow area has been to correct brow ptosis. However, there are several other conditions that may be improved by surgery in this area, including frown muscle imbalance, transverse forehead rhytids, and lateral brow laxity. Recently, a better understanding of the relevant anatomy and the evolving therapeutic modalities (including both open and closed techniques) have contributed to a renewed interest in aesthetic surgery in the forehead and brow area. One hundred consecutive patients were studied, each of whom underwent forehead rejuvenation for one of four indications-forehead rhytids, glabellar creases, lateral brow laxity, or brow ptosis. Thirty-eight percent of patients underwent open procedures, 30 percent underwent closed procedures, and 32 percent underwent limited procedures. Complications occurred in 4 percent of patients, including three patients who were dissatisfied with the surgery and one patient who required scar revision. Based on our findings, we formulated an algorithm that integrates the different indications and any concomitant procedures being performed. Our proposed treatment plan is based on this information. The algorithm may be used as a template when assessing a patient and adapting the recommended intervention to the individual patient.  相似文献   

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Endoscopy has provided a significant improvement in the surgical rejuvenation of the upper face. It offers a minimally invasive alternative that avoids many of the undesirable effects associated with the coronal approach. The standard minimal access forehead endoscopic procedure consists of a subperiosteal undermining through three small triangular prehairline incisions. To successfully elevate the eyebrows, it is essential to release the periosteum at the level of the supraorbital rims and ablate the brow depressor muscles of the glabella. Until the periosteum reattaches itself, elevation is maintained by a temporary suspension suture between staples at the incision sites and 5 cm posterior to the hairline. The transverse closure of the triangular skin incisions achieves some additional elevation. The biplanar approach adds a partial subcutaneous undermining of the forehead to the endoscopic technique and allows plication of the frontalis muscle and excision of excess forehead skin. It is offered to patients with very ptotic eyebrows, deep transverse wrinkles, or a high forehead. The prehairline incision is a disadvantage but is tolerated quite well in older patients. The medical records of 393 consecutive patients who underwent endoscopic forehead lift from 1994 to 2000 were reviewed. Because seven patients had the endoscopic forehead lift repeated, the number of forehead endoscopies totaled 400. The complication rate was quite acceptable and did not markedly increase when a forehead lift was performed in combination with other facial procedures. The endoscopic forehead lift consistently attenuated the transverse forehead wrinkles, reduced the glabellar frown lines, and raised the eyebrows. It provided an appearance that was less tired and angry in addition to opening the area around the eyes. Long-term follow-up has shown that the endoscopic forehead lift produces lasting and predictable results.  相似文献   

8.
One hundred years ago the striped bassMorone saxatilis was introduced in the San Francisco Bay estuarine system from the east coast of the United States. It was part of our national policy at the time to transplant all potentially useful species everywhere else. The policy was facilitated by completion of the transcontinental railroad in 1869. As a result, the present ichthyofauna of the San Francisco Bay area is largely alien. Introduction of eastern oystersCrassostrea virginica resulted in the inadvertent introduction of many species of invertebrates. Identification of these introduced species was not realized as a problem until recently, and no one knows how many exotic species there are. In other parts of the world there are examples of similar introductions, e.g.Crepidula fornicata andRhithropanopeus harrisi in Europe. Although it is now the policy to frown upon and prohibit introductions, they cannot be prevented and the process still continues, as witnessed by the examples ofElminus modestus in Europe andPalaemon macrodactylus in California. In the USA the recently developed idea of “mitigation,” the artificial replacement of disturbed or destroyed areas by development of quasi-natural areas in compensation, has been accompanied, at the hands of inexperienced practitioners, by potentially dangerous introductions of exotic species. The assumption, for example, that cordgrass(Spartina) should be equally beneficial everywhere in the world has led to the disrupting introduction of potentially hybridizing species in New Zealand and aggressive immigrants in Oregon marshes. This situation calls for more sophisticated understanding of the role of introduced species in natural aquatic ecosystems, and a higher degree of competence in systematic biology.  相似文献   

9.
We report measurements of atmospheric composition over a tropical rainforest and over a nearby oil palm plantation in Sabah, Borneo. The primary vegetation in each of the two landscapes emits very different amounts and kinds of volatile organic compounds (VOCs), resulting in distinctive VOC fingerprints in the atmospheric boundary layer for both landscapes. VOCs over the Borneo rainforest are dominated by isoprene and its oxidation products, with a significant additional contribution from monoterpenes. Rather than consuming the main atmospheric oxidant, OH, these high concentrations of VOCs appear to maintain OH, as has been observed previously over Amazonia. The boundary-layer characteristics and mixing ratios of VOCs observed over the Borneo rainforest are different to those measured previously over Amazonia. Compared with the Bornean rainforest, air over the oil palm plantation contains much more isoprene, monoterpenes are relatively less important, and the flower scent, estragole, is prominent. Concentrations of nitrogen oxides are greater above the agro-industrial oil palm landscape than over the rainforest, and this leads to changes in some secondary pollutant mixing ratios (but not, currently, differences in ozone). Secondary organic aerosol over both landscapes shows a significant contribution from isoprene. Primary biological aerosol dominates the super-micrometre aerosol over the rainforest and is likely to be sensitive to land-use change, since the fungal source of the bioaerosol is closely linked to above-ground biodiversity.  相似文献   

10.
Vertical wind shear and concentration gradients of viable, airborne bacteria were used to calculate the upward flux of viable cells above bare soil and canopies of several crops. Concentrations at soil or canopy height varied from 46 colony-forming units per m3 over young corn and wet soil to 663 colony-forming units per m3 over dry soil and 6,500 colony-forming units per m3 over a closed wheat canopy. In simultaneous samples, concentrations of viable bacteria in the air 10 m inside an alfalfa field were fourfold higher than those over a field with dry, bare soil immediately upwind. The upward flux of viable bacteria over alfalfa was three- to fourfold greater than over dry soil. Concentrations of ice nucleation-active bacteria were higher over plants than over soil. Thus, plant canopies may constitute a major source of bacteria, including ice nucleation-active bacteria, in the air.  相似文献   

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Honeybee odometry: performance in varying natural terrain   总被引:3,自引:1,他引:2       下载免费PDF全文
Recent studies have shown that honeybees flying through short, narrow tunnels with visually textured walls perform waggle dances that indicate a much greater flight distance than that actually flown. These studies suggest that the bee's “odometer” is driven by the optic flow (image motion) that is experienced during flight. One might therefore expect that, when bees fly to a food source through a varying outdoor landscape, their waggle dances would depend upon the nature of the terrain experienced en route. We trained honeybees to visit feeders positioned along two routes, each 580 m long. One route was exclusively over land. The other was initially over land, then over water and, finally, again over land. Flight over water resulted in a significantly flatter slope of the waggle-duration versus distance regression, compared to flight over land. The mean visual contrast of the scenes was significantly greater over land than over water. The results reveal that, in outdoor flight, the honeybee's odometer does not run at a constant rate; rather, the rate depends upon the properties of the terrain. The bee's perception of distance flown is therefore not absolute, but scene-dependent. These findings raise important and interesting questions about how these animals navigate reliably.  相似文献   

13.
Temperature data for phenological models   总被引:5,自引:0,他引:5  
In an arid environment, the effect of evaporation on energy balance can affect air temperature recordings and greatly impact on degree-day calculations. This is an important consideration when choosing a site or climate data for phenological models. To our knowledge, there is no literature showing the effect of the underlying surface and its fetch around a weather station on degree-day accumulations. In this paper, we present data to show that this is a serious consideration, and it can lead to dubious models. Microscale measurements of temperature and energy balance are presented to explain why the differences occur. For example, the effect of fetch of irrigated grass and wetting of bare soil around a weather station on diurnal temperature are reported. A 43-day experiment showed that temperature measured on the upwind edge of an irrigated grass area averaged 4% higher than temperatures recorded 200 m inside the grass field. When the single-triangle method was used with a 10°C threshold and starting on May 19, the station on the upwind edge recorded 900 degree-days on June 28, whereas the interior station recorded 900 degree-days on July 1. Clearly, a difference in fetch can lead to big errors for large degree-day accumulations. Immediately after wetting, the temperature over a wet soil surface was similar to that measured over grass. However, the temperature over the soil increased more than that over the grass as the soil surface dried. Therefore, the observed difference between temperatures measured over bare soil and those over grass increases with longer periods between wettings. In most arid locations, measuring temperature over irrigated grass gives a lower mean annual temperature, resulting in lower annual cumulative degree-day values. This was verified by comparing measurements over grass with those over bare soil at several weather stations in a range of climates. To eliminate the effect of rainfall frequency, using temperature data collected only over irrigated grass, is recommended for long-term assessment of climate change effects on degree-day accumulation. In high evaporative conditions, a fetch of at least 100 m of grass is recommended. Our results clearly indicate that weather stations sited over bare soil have consistently higher degree-day accumulations. Therefore, especially in arid environments, phenology models based on temperature collected over bare soil are not transferable to those based on temperature recorded over irrigated grass. At a minimum, all degree-day-based phenology models reported in the literature should clearly describe the weather station site. Received: 25 October 2000 / Revised: 10 July 2001 / Accepted: 10 July 2001  相似文献   

14.
Summary Nucleic acids have been localized inAllium porrum interphase meristematic cells by means of labelling with nuclease-gold complexes, a technique which provides high resolution and improved specificity. DNase-gold labelling was observed over dense chromatin and to a lesser extent over dispersed chromatin. Nucleolar labelling was restricted to the dense fibrillar component, very few particles being located over the fibrillar centres. Labelling by the RNase-gold complex was present over both the cytoplasm and the nucleoplasm. Cytoplasm labelling was intense over the rough endoplasmic reticulum but absent over vacuoles. In the nucleoplasm many gold particles were located at the border between the condensed and the dispersed chromatin. Nucleolar labelling was intense over the granular zones but many gold particles were also seen over the dense fibrillar component. Fibrillar centres showed, however, no labelling with the RNase-gold complex. These results are consistent with previous autoradiographic and cytochemical observations carried out on the same plant material.  相似文献   

15.
Crossing over in the left arm of chromosome 2 (2L) was studied in successive broods of Drosophila melanogaster females carrying intact chromosomes (+/+), inversion Muller-5 in the X chromosome (M-5/+), and insertion of the Y-chromosome material into region 34A (Is(2L)/+). The regions net-dp, dp-b, b-pr and pr-cn were examined in 14 two-day-old broods of females +/+ and M-5/+ and in 10 broods of females Is(2L)/+. In all lines, the highest level of crossing over was in the first three broods (eggs laid during the first 6 days of oviposition) and the lowest level in the broods 7-8 (eggs laid at days 14-16). A high rate of crossing over in the first broods of females +/+ and M-5/+ was due to an increment of exchanges in the proximal euchromatin regions (b-pr and pr-cn) and to an increase in the number of tetrads with double exchanges. These changes are similar to a pattern of the interchromosomal effect on crossing over (IEC) in structurally normal chromosomes. In Is(2L)/+ females, a high level of crossing over was due to extensive exchanges in the interstitial regions net-dp and dp and an increase in the number of tetrads with single exchanges. These changes resembled the IEC in rearranged chromosomes (in this case, in chromosomes bearing an insertion). Thus, the age changes of crossing over are similar to the consequences of the presence or absence of IEC. Age changes in crossing over in a chromosome depended both on the local rearrangements in this chromosome (the local effect on crossing over, LEC) and on rearrangements in nonhomologous chromosomes (IEC). In the first broods, both LEC and IEC decreased with an increase in the level of crossing over. In subsequent broods, the reduced level of crossing over was accompanied by an increase in both LEC and IEC. This suggests that the mechanisms responsible for the age changes in crossing over and IEC may have common steps. The contact model of crossing over may explain the similarity between the age changes in crossing-over and IEC. It is suggested that both phenomena result from delayed determination of crossing over in a meiotic cell. This may occur due to the retarded formation of the local contacts in one of the homologous chromosome pairs or because a higher number of local contacts is required to trigger crossing over in a meiotic cell (of early age).  相似文献   

16.
This overview and synthesis paper focuses on the evolution of urban biogeochemical cycles across time. We synthesize empirical data and review existing literature, including papers in this special issue, and we propose the concept of “urban evolution.” The built environment often changes quickly in response to human activities, thus contributing to an urban evolution that affects structure, function, and ecosystem services of human settlements over time. Depending upon management, these changes can result in rapid losses of ecosystem functions/services or progress towards restoration. We explore urban evolution through empirical examples such as: (1) land development and nitrogen inputs within a metropolitan region over half a century; (2) watershed drainage by different forms of stormwater management over decades; (3) human-accelerated weathering in urbanized watersheds over decades; and (4) global salinization of freshwater across urbanizing landscapes over a century. We also synthesize concepts relevant to studying urban evolution of infrastructure and ecosystems including: (1) urban watersheds have challenged our whole notion of the “watershed approach” due to complex hydrologic boundaries and flow paths over time; (2) the urban hydrologic cycle evolves due to changing infrastructure and human water use over time; (3) the importance of extending research beyond individual sites using an urban watershed approach over space and time; (4) salinization as a universal tracer of watershed urbanization over time; (5) human-accelerated weathering of concrete and construction materials contributing to an “urban karst” over time; (6) human alteration of the carbon cycle in urban watersheds over time; and (7) detecting distinct biogeochemical signatures across cities globally over time. Our synthesis and this special issue suggest that urban biogeochemical cycles have exerted a major influence on the elemental composition of the Earth’s surface from local to global scales. A new global research agenda is needed to track the evolution of urban biogeochemical cycles as land development proceeds and infrastructure/management changes so we can better evaluate potential losses in ecosystem services, set realistic watershed and river restoration goals, and formulate effective environmental policy for Earth’s growing urban population.  相似文献   

17.
Enhancers and insulators are regulatory DNA sequences that can work over a large distance. Efficient action over a distance clearly requires special mechanisms for facilitating communication between a regulatory region and its target. Studies from our laboratory identified DNA supercoiling as primary factor that mediates efficient enhancer-promoter communication over a distance in prokaryotes through a “DNA slithering” mechanism. These studies allowed rational design and construction of an insulator that can block enhancer action over a distance both in vitro and in vivo. Our most recent studies suggest that eukaryotic chromatin structure can support action over a distance using similar principles, but in a mechanistically distinct way. Published in Russian in Molekulyarnaya Biologiya, 2009, Vol. 43, No. 2, pp. 204–214. The article was translated by the author.  相似文献   

18.
Absorption of 14C from the marine alga Enteromorpha by an herbivorous marine fish, the luderick, Girella tricuspidata , was used to demonstrate the capability of this species to utilize an herbivorous diet. Absorption of 14C from protoplasts and cell walls clearly demonstrated a capability of the luderick to utilize cell walls. Two patterns of absorption of algal fractions were seen, but in all cases isotope absorption by the fish was highest from protoplasts over a 16-h digestion period. The first pattern, demonstrated by the absorptive tissues of the gut, showed greater absorption of the radioactive label from cell walls over 5 days than over 16 h. The second, occurring in the anterior regions of the gut and in the liver and spleen, showed greater absorption of 14C from cell walls over 16 h than over 5 days. It is suggested that the marker found in this second group of tissues derives from absorption in the pyloric caeca, the only absorptive region showing significant absorption of carbon label from cell walls over 16 h. Absorption of 14C from cell walls is greater over 5 days than over 16 h.  相似文献   

19.
Individual happiness is a fundamental societal metric. Normally measured through self-report, happiness has often been indirectly characterized and overshadowed by more readily quantifiable economic indicators such as gross domestic product. Here, we examine expressions made on the online, global microblog and social networking service Twitter, uncovering and explaining temporal variations in happiness and information levels over timescales ranging from hours to years. Our data set comprises over 46 billion words contained in nearly 4.6 billion expressions posted over a 33 month span by over 63 million unique users. In measuring happiness, we construct a tunable, real-time, remote-sensing, and non-invasive, text-based hedonometer. In building our metric, made available with this paper, we conducted a survey to obtain happiness evaluations of over 10,000 individual words, representing a tenfold size improvement over similar existing word sets. Rather than being ad hoc, our word list is chosen solely by frequency of usage, and we show how a highly robust and tunable metric can be constructed and defended.  相似文献   

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