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1.
A classification of facial wrinkles.   总被引:6,自引:0,他引:6  
An increasing number of injectable filler materials for facial wrinkles and folds points to the need for objective measurements of their effectiveness. Patient satisfaction is the goal, but proof of the value of a particular product requires objective measurement. A wrinkle assessment scale was developed as a simple tool for use by plastic surgeons, dermatologists, and aesthetic surgeons who want to assess the changes resulting from injecting filler materials in their patients. By correlating the grade of the wrinkle in the reference photographs with the wrinkle in a patient's face, a classification of 0 to 5 is assigned. Reliability of the scale was assessed by "live" judgment of 76 wrinkles by nine observers. The same rating was given to 92.7 percent of all wrinkles. In a second trial, photographs from 130 wrinkles were presented to eight observers who rated 89.4 percent of all wrinkles equally. A significant correlation of 87 percent was found between subjective ratings and objective wrinkle depth measured by profilometry on 40 silicone impressions. Manufacturers, monitors of clinical trials, health authorities, and most important, patients will benefit from objective data on current and new injectable materials.  相似文献   

2.
In 2002, a new chronic kidney disease staging system was developed by the US National Kidney Foundation. The classification system represented a new conceptual framework for the diagnosis of chronic kidney disease (moving to a schema based on disease severity defined by the glomerular filtration rate). While the introduction of the staging system stimulated significant clinical and research interest in kidney disease, there has been vigorous debate on its merits. This mini-review aims to summarise the recent controversies that have been raised since the introduction of the new classification.  相似文献   

3.
In this review, we propose a new classification of vertebrate cilia/flagella and discuss the evolution and prototype of cilia. Cilia/flagella are evolutionarily well-conserved membranous organelles in eukaryotes and serve a variety of functions, including motility and sensation. Vertebrate cilia have been traditionally classified into conventional motile cilia and sensory primary cilia. However, an avalanche of emerging evidence on the variations of cilia has made it almost impossible to classify them in a simple dichotomic manner. For example, conventional motile cilia are also involved in the sensation of bitter taste to facilitate the beating of cilia as a defense system of the respiratory system. On the other hand, the primary cilium, often regarded as a non-motile sensory organelle, has been revealed to be motile in vertebrate embryonic nodes, where they play a crucial role in the determination of left-right asymmetry of the body. Moreover, choroid plexus epithelial cells in the cerebral ventricular system exhibit multiple primary cilia on a single cell. Considering these lines of evidence on the diversity of cilia, we believe the classification of cilia should be based on their structure and function, and include more detailed criteria. Another intriguing issue is how in the evolution of cilia, their function and morphology are combined. For example, has motility been acquired from originally sensory cilia, or vice versa? Alternatively, were they originally hybrid in nature? These questions are inseparable from the classification of cilia per se. We would like to address these conundrums in this review article, principally from the standpoint of differentiation of the animal cell.  相似文献   

4.
A new approach is introduced for determining the intrinsic guild classification of a group of species. Previous delimitations of intrinsic guilds have used evidence of spatial distributions (i.e. species co-occurrences), but this is rather indirect evidence. The new method is based on the results of species pairwise competition experiments, and thus uses direct data on species interactions. As with the spatial-distribution intrinsic guild approach, no prior assumptions are made about the classification, nor about which characters are related to guild membership.
The method is applied to the results of two published experiments. For one, little independent evidence is available to judge the classification. There is no correlation between the guild classification obtained and gross morphology, but there is no reason to expect any such correlation. For the second experiment, intrinsic guild classifications had previously been obtained from distributional data, and the experimentally-based intrinsic classifications was identical to a distributionally-based one.
We suggest that combining evidence from field distributions with experimental evidence offers a rigorous way to determine the true guild structure of communities, offering convincing conclusions when the two lines of evidence converge.  相似文献   

5.
In a previous work (part 1), nanocomposite materials were obtained using a latex of either unvulcanized or prevulcanized natural rubber as the matrix and a colloidal suspension of crab chitin whiskers as the reinforcing phase. The mechanical behavior of the resulting nanocomposite films was analyzed in both the linear and the nonlinear range in the present study. The effects of the filler and processing technique were evaluated, and the results are discussed based on the knowledge of the structural morphology and swelling behavior reported in our previous work. The reinforcing effect of chitin whiskers strongly depended on their ability to form a rigid three-dimensional network, resulting from strong interactions such as hydrogen bonds between the whiskers. The results emanating from the successive tensile test experiments give clear evidence for the presence of a three-dimensional chitin network within the evaporated samples. Cross-linking of the matrix was found to interfere with the formation of this network.  相似文献   

6.

Purpose

Polymers typically have intrinsic thermal conductivity much lower than other materials. Enhancement of this property may be obtained by the addition of conductive fillers. Nanofillers are preferred to traditional ones, due to their low percolation threshold resulting from their high aspect ratio. Beyond these considerations, it is imperative that the development of such new fillers takes place in a safe and sustainable manner. A conventional life cycle assessment (LCA) has been conducted on epoxy-based composites, filled with graphite nanoplatelets (GnP). In particular, this study focuses on energy requirements for the production of such composites, in order to stress environmental hot spots and primary energy of GnP production process (nano-wastes and nanoparticles emissions are not included).

Methods

A cradle-to-grave approach has been employed for this assessment, in an attributional modeling perspective. The data for the LCA have been gathered from both laboratory data and bibliographic references. A technical LCA software package, SimaPro (SimaPro 7.3), which contains Ecoinvent (2010) life cycle inventory (LCI) database, has been used for the life cycle impact assessment (LCIA), studying 13 mid-point indicators. Sensitivity and uncertainty analyses have also been performed.

Results and discussion

One kilogram of GnP filler requires 1,879 MJ of primary energy while the preparation of 1 kg of epoxy composite loaded with 0.058 kg of GnP 303 MJ. Besides energy consumption in the filler preparation, it is shown that the thermoset matrix material has also a non-negligible impact on the life cycle despite the use of GnP: the primary energy required to make epoxy resin is 187 MJ, i.e., 62 % of the total energy to make 1 kg of composite.

Conclusions

Raw material extraction and filler and resin preparation phase exhibit the highest environmental impact while the composite production is negligible. Thermosetting resin remains the highest primary energy demand when used as matrix for GnP fillers. The result of the sensitivity analysis carried out on the electricity mix used during the GnP and the composite production processes does not affect the conclusions.  相似文献   

7.
Summary. Plants that parasitise other plants have been among the most difficult plant groups to fit into classification systems due to their modified biology and their often highly reduced morphology. They are now considered to be found in about 16 families of flowering plants. Here we summarise current ideas about their relationships and provide information about their characteristics and utilisation. A major consequence of the revised classification of Orobanchaceae and related families has been the break-up of the traditional Scrophulariaceae, and here we summarise the new classification, focusing on genera of horticultural interest.  相似文献   

8.
Nanocomposite materials based on a starch matrix reinforced with very small amounts of multi-walled carbon nanotubes (MWCNTs) (from 0.005 wt% to 0.055 wt%) were developed. The material's dynamic-mechanical and water vapor permeability properties were investigated. An increasing trend of storage modulus (E′) and a decreasing trend of water vapor permeability (WVP) with filler content were observed at room temperature. For the composite with 0.055 wt% of filler, E′ value was about 100% higher and WVP value was almost 43% lower than the corresponding matrix values. MWCNTs were wrapped in an aqueous solution of a starch-iodine complex before their incorporation into the matrix, obtaining exceptionally well-dispersed nanotubes and optimizing interfacial adhesion. This excellent filler dispersion leads to the development of an important contact surface area with the matrix material, producing remarkable changes in the starch-rich phase glass transition temperature even in composites with very low filler contents. This transition is shifted towards higher temperatures with increasing content of nanotubes. So at room temperature, some composites are in the rubber zone while others, in the transition zone. Therefore, this change in the material glass transition temperature can be taken as responsible for the important improvements obtained in the composites WVP and E′ values for carbon nanotubes content as low as 0.05 wt%.  相似文献   

9.
This study was based on the influence of lignocellulosic fillers and content on the morphology, crystallization behavior and thermal, mechanical and barrier properties of fully biodegradable eco-composites based on polycaprolactone for packaging applications. The biodegradation in soil as a function of time was also analyzed. Composites with 5 and 15 wt% of cotton (CO); cellulose (CE) and hydrolyzed-cellulose (HCE) were prepared by melt-mixing. It was determined that, whereas lower content of CO and CE produced a decrease on the crystallinity of the matrix, HCE did not affect it. Increasing the filler content, the crystallinity degree of the matrix decreased at less extent, which was independent on the filler type. A clear reduction on the theoretical melting point, attributed to heterogeneous nucleation sites, took place for the lower content of CO and CE. Induction and half-crystallization times diminished when fillers were incorporated but the effect was less notorious at higher filler contents. All fillers enhanced the Young's modulus of the matrix but the optimal mechanical properties were not obtained with HCE, as was expected, but with CE. After analyzing the main parameters that affect the mechanical properties of the composite; such as morphology, hydrophilicity, crystallinity, mechanical properties and thermal stability of the fillers themselves, interface interaction, filler dispersion and thermal aspects of the composites, we concluded that the parameters responsible for such behavior were the larger aspect ratio, better dispersion and enhanced interface interaction of the CE filler. These parameters also affected the barrier properties and the process of biodegradation in soil of the composites.  相似文献   

10.
This paper is focused on the analysis of the thermal and mechanical behaviour of processed biocomposites (biodegradable composites). These materials have been created by extrusion and injection moulding. The matrix, a biodegradable and aromatic copolyester (polybutylene adipate-co-terephthalate), has been fully characterised (NMR, SEC). The lignocellulosic materials used as fillers are a by-product of an industrial fractionation process of wheat straw. Different filler fractions have been selected by successive sieving, and then carefully analysed (granulometry, chemical structure). Cellulose, lignin, and hemicellulose contents have been determined through different techniques. The biocomposites thermal behaviour has been investigated by TGA (thermal degradation) and DSC (transition temperatures, crystallinity). These materials present good mechanical behaviour due to high filler-matrix compatibility. The impacts of filler content, filler size and the nature of each fraction have been analysed. To predict the mechanical behaviour, Takayanagi’s equation seems to provide an accurate answer to evaluate the modulus in a range, 0–30 wt% of fillers.  相似文献   

11.
余盼  赵国柱  徐锐 《菌物研究》2012,10(3):177-181,209
气-水两生型真菌通常定植于自然森林生态系统中溪流或池塘沉积的腐枝叶上,菌丝生长于水体底部,当沉积物暴露于空气中时,形成分生孢子并发育成中空的孢子繁殖体,使其能漂浮在水面,附着新的基质,进行生长繁殖。世界范围内已报道约20属116种,大多为无性型的丝孢菌,其独特的生存环境和产孢特点,在真菌的形态、生态和系统演化上有重要研究价值。文中主要从多样性和分类学、采集与分离培养、孢子形态和发育、有性型-无性型关系、系统演化关系等方面对其进行了综述,为该类真菌系统的研究及潜在的应用提供参考。  相似文献   

12.
Thermoplastic starch-waxy maize starch nanocrystals nanocomposites   总被引:1,自引:0,他引:1  
Waxy maize starch nanocrystals obtained by hydrolysis of native granules were used as a reinforcing agent in a thermoplastic waxy maize starch matrix plasticized with glycerol. Compared to our previous studies on starch nanocrystals reinforced natural rubber (NR) [Macromolecules 2005, 38, 3783; 2005, 38, 9161], the present system presents two particularities: (i) thermoplastic starch is a polar matrix, contrarily to NR, and (ii) the chemical structures of the matrix and the filler are similar. The influence of the glycerol content, filler content, and aging on the reinforcing properties of waxy maize starch nanocrystals (tensile tests, DMA) and crystalline structure (X-ray diffraction) of materials were studied. It was shown that the reinforcing effect of starch nanocrystals can be attributed to strong filler/filler and filler/matrix interactions due to the establishment of hydrogen bonding. The presence of starch nanocrystals leads to a slowing down of the recrystallization of the matrix during aging in humid atmosphere.  相似文献   

13.
14.
Cao X  Dong H  Li CM 《Biomacromolecules》2007,8(3):899-904
New nanocomposite films were prepared from a suspension of cellulose nanocrystals as the filler and a polycaprolactone-based waterborne polyurethane (WPU) as the matrix. The cellulose nanocrystals, prepared by acid hydrolysis of flax fiber, consisted of slender rods with an average length of 327 +/- 108 nm and diameter of 21 +/- 7 nm, respectively. After the two aqueous suspensions were mixed homogeneously, the nanocomposite films were obtained by casting and evaporating. The morphology, thermal behavior, and mechanical properties of the films were investigated by means of attenuated total reflection Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and tensile testing. The results indicated that the cellulose nanocrystals could disperse in the WPU uniformly and resulted in an improvement of microphase separation between the soft and hard segments of the WPU matrix. The films showed a significant increase in Young's modulus and tensile strength from 0.51 to 344 MPa and 4.27 to 14.86 MPa, respectively, with increasing filler content from 0 to 30 wt %. Of note is that the Young's modulus increased exponentially with the filler up to a content of 10 wt %. The synergistic interaction between fillers and between the filler and WPU matrix played an important role in reinforcing the nanocomposites. The superior properties of the new nanocomposite materials could have great potential applications.  相似文献   

15.
Recent studies have identified extracellular matrix (ECM) compliance as an influential factor in determining the fate of anchorage-dependent cells. We explore a method of examining the influence of ECM compliance on cell morphology and remodeling in three-dimensional culture. For this purpose, a biological ECM analog material was developed to pseudo-independently alter its biochemical and physical properties. A set of 18 material variants were prepared with shear modulus ranging from 10 to 700 Pa. Smooth muscle cells were encapsulated in these materials and time-lapse video microscopy was used to show a relationship between matrix modulus, proteolytic biodegradation, cell spreading, and cell compaction of the matrix. The proteolytic susceptibility of the matrix, the degree of matrix compaction, and the cell morphology were quantified for each of the material variants to correlate with the modulus data. The initial cell spreading into the hydrogel matrix was dependent on the proteolytic susceptibility of the materials, whereas the extent of cell compaction proved to be more correlated to the modulus of the material. Inhibition of matrix metalloproteinases profoundly affected initial cell spreading and remodeling even in the most compliant materials. We concluded that smooth muscle cells use proteolysis to form lamellipodia and tractional forces to contract and remodel their surrounding microenvironment. Matrix modulus can therefore be used to control the extent of cellular remodeling and compaction. This study further shows that the interconnection between matrix modulus and proteolytic resistance in the ECM may be partly uncoupled to provide insight into how cells interpret their physical three-dimensional microenvironment.  相似文献   

16.
New embryological evidence in angiosperm classification is presented from two different lines of research. One deals with a new field in embryological research, the other keeps within the classical framework. The new approach encouraged by the author refers to the exploration of the chemical composition of the pollen tube as a taxonomic tool. The presence of callose in several pollen tubes and the lack of this compound in others has been correlated with other embryological and taxonomical features within the Tubiflorae, showing a great deal of correspondence. In order to exemplify the classical approach, two families have been selected: Loranthaceae and Hydnoraceae. The Loranthaceae have a special structure called the "mamelon", usually interpreted as a placenta. Recent research based on the position of the ar–chesporial tissue shows that not all "mamelons" should be regarded as homologous structures. Based on this finding, a new scheme of evolutionary lines is proposed. In connection with the holoparasitic family Hydnoraceae, the author discusses its relationships with Mitrastemonaceae and Annonaceae on grounds of embryology and floral morphology.  相似文献   

17.
A method of care for these infected nonunions is prolonged intravenous systemic antibiotic treatment and implantation of methyl methacrylate antibiotic carrier beads to delivery high local doses of antibiotics. This method requires a second surgery to remove the beads once the infection has cleared. Recent studies have investigated the use of biodegradable materials that have been impregnated with antibiotics as tools to treat bone infections. In the present study, human demineralized bone matrix (DBM) was investigated for its ability to be loaded with an antibiotic. The data presented herein demonstrates that this osteoinductive and biodegradable material can be loaded with gentamicin and release clinically relevant levels of the drug for at least 13 days in vitro. This study also demonstrates that the antibiotic loaded onto the graft has no adverse effects on the osteoinductive nature of the DBM as measured in vitro and in vivo. This bone void filler may represent a promising option for local antibiotic delivery in orthopedic applications.  相似文献   

18.
Polymastiidae Gray, 1867 is a worldwide distributed sponge family, which has a great significance for understanding of the demosponge deep phylogeny since the former order Hadromerida Topsent, 1894 has been recently split based on the molecular evidence and a new separate order has been established for the polymastiids. However, molecular data obtained from Polymastiidae so far are scarce, while the phylogenetic reconstruction based on morphology has faced a deficit of characters along with the vagueness of their states. The present study is a phylogenetic reconstruction of Polymastiidae based on novel data on two molecular markers, cytochrome oxidase subunit I and large subunit ribosomal DNA, obtained from a broad set of species. Monophyly of the family and nonmonophyly of four polymastiid genera are revealed, suggesting a high level of homoplasy of morphological characters, which are therefore not an appropriate base for the natural classification of Polymastiidae. Although the presented phylogenies cannot yet provide an alternative classification scheme, several strongly supported clades, which may be used as reference points in future classification, are recovered and three taxonomic actions are proposed: transfer of one species from Radiella to Polymastia Bowerbank, 1862; transfer of three species from Radiella Schmidt, 1870 to Spinularia Gray, 1867; and the consequent abandonment of Radiella.  相似文献   

19.
20.
Although high power conversion efficiency of over 14% has been achieved using nonfullerene acceptors (NFAs) in organic photovoltaics (OPVs), securing their insensitive device performance to the thickness of the photoactive layer remains an indispensable requirement for their successful commercialization via printing technologies. In this study, by synthesizing a new series of ITIC‐based NFAs having alkyl or alkoxy groups, it is found that the bulk heterojunction morphology dependence on the thickness of the photoactive layer becomes more severe as the difference in the surface energy of the donor and acceptor increases. It is believed that this observation is the origin that yields the device performance dependence on the thickness of the photoactive layer. Through sensitive control of the surface energy of these ITIC‐based NFAs, it is demonstrated that thickness‐insensitive OPVs can be achieved even using a doctor blade technique under air without using any additives. It is believed that present approach provides an important insight into the design of photoactive materials and morphology control for the printable OPVs using NFAs.  相似文献   

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