海南主要陆域自然保护地兰科植物多样性与生境的关联分析

为了掌握海南主要陆域自然保护地内野生兰科植物的物种多样性现状以及制约其发展的关键生境因子,对该地区进行兰科植物资源调查并分析兰科植物多样性的空间分布格局,进一步采用典范对应分析(CCA)探索生境因子对兰科植物组成的影响,最后运用广义线性模型(GLM)框架下的负二项回归拟合兰科植物丰富度和多度对生境变异的响应。结果表明:(1)共发现兰科植物67属193种,为海南兰科植物分布的绝对中心。(2)水平方向上,霸王岭兰科植物丰富度高但居群相对拥挤,而五指山最大的海拔落差带来了更加多样化的小生境类型和宽阔的生存空间,孕育了种类丰富且分布均匀的兰科植物资源。(3)垂直方向上,中海拔地区兰科植物种类最为丰富且种间竞争较为激烈,高海拔地区则存在明显的优势类群。(4)海拔变化对兰科植物物种组成变异有着非常高的解释率,而喀斯特和河谷地貌的显著影响也不容忽视。(5)多因子综合作用共同影响着兰科植物的多样性,其中坡度、河谷地貌、喀斯特地貌的显著正效应和枫香林的显著负效应受其他协变量的影响较小,是驱动兰科植物丰富度和多度变化的关键生境因子。综上所述,中高海拔地区以及特殊地貌(如河谷和喀斯特地貌)应作为兰科植物多样性的优先保护区域。     

Candida albicans biofilm formation on soft denture liners and efficacy of cleaning protocols

doi: 10.1111/j.1741‐2358.2011.00485.x
Candida albicans biofilm formation on soft denture liners and efficacy of cleaning protocols Objective: The aim of this study was to investigate Candida albicans biofilm formation on denture liners and to analyse the efficacy of cleaning protocols. Material and methods: Specimens were prepared from four silicone‐based soft denture liners. After artificial ageing and surface free energy determination, specimens were incubated with saliva (2 h) and Candida albicans ATCC 10231 for either short‐ (2.5 h) or long‐term (24 h) biofilm formation. Adherent cells were determined either after incubation of specimens with Candida albicans or after treatment with different denture cleaning protocols. Statistical analysis was performed using one‐way anova and the Games–Howell test (α = 0.05). Results: For both short‐ and long‐term biofilm formation, similar amounts of Candida albicans cells were found on the surface of the different liners (p = 0.295 and 0.178, respectively). For both short‐ and long‐term biofilm formation, the highest cleaning efficacy was observed for sodium hypochlorite (NaOCl; p < 0.01). The efficacy of the chemical denture cleaner in removing long‐term Candida albicans biofilms was significantly lower than the efficacy of removal by brushing (p < 0.001). Conclusion: Different silicone‐based soft denture liners yield similar Candida albicans biofilm formation on their surface. The highest efficacy for the removal of Candida albicans biofilms was identified for NaOCl. Chemical denture cleaners appear to have rather low efficacy to remove mature Candida albicans biofilms.     

Oral health related quality of life of edentulous patients after denture relining with a silicone-based soft liner

doi: 10.1111/j.1741‐2358.2011.00503.x Oral health related quality of life of edentulous patients after denture relining with a silicone‐based soft liner Background: Knowledge of benefits caused by a treatment on quality of life is very relevant. Despite the wide use and acceptance of soft denture liners, it is necessary to evaluate the patient’s response about the use of these materials with regard to improvement in oral health related quality of life (OHRQoL). Objectives: The aim of this study was to evaluate the influence of denture relining in the OHRQoL of edentulous patients. Materials and methods: Thirty‐two complete denture wearers had their lower dentures relined with a silicone‐based material (Mucopren soft, Kettenbach, Germany) according to chairside procedures. OHRQoL was assessed before and after 3 months of relining by means of OHIP‐EDENT, and the median scores were compared by Wilcoxon test (p ≤ 0.05). Results: After 3 months of relining, participants reported significant improvement of their OHRQoL (p ≤ 0.01). Conclusion: Denture relining with a soft liner may have a positive impact on the perceived oral health of edentulous patients.     

Sedimentary Residual Soil as a Waste Containment Barrier Material

Compacted soil liners are widely used as a waste containment barrier to control or restrict the migration of contaminant/leachate from the landfill into the environment because of their low hydraulic conductivity, attenuation capacity, resistance to damage or puncture, and cost effectiveness. Compacted soil liners are usually composed of natural inorganic clays or clayey soils. If natural clayey soils are not available, kaolinite or commercially available high swelling clay (bentonite) can be mixed with local soils or sand. This study examines the potential of a sedimentary residual soil as a waste containment barrier in landfills. The laboratory experiments conducted were: grain size distribution, Atterberg limits, swelling tests, compaction, volumetric shrinkage strain, unconfined compression, hydraulic conductivity and cation exchange capacity. The experimental results were compared with those recommended by various researchers for evaluation of its suitability. Test results showed that the soil compacted with modified Proctor compaction effort possesses low hydraulic conductivity (≤1 × 10^?7 cm/s) and adequate strength. In addition, compacted sedimentary residual soil exhibited little volumetric shrinkage strain of below 4% at this compaction effort. Thus, the sedimentary residual soil could be effectively used for the construction of a waste containment barrier in landfills.     

The influence of branches and leaf area on rooting and development of Cotinus coggygria cv. Royal Purple cuttings

The influence of branches and mature leaves on the rooting and subsequent development of cuttings was examined, using Cotinus coggygria cv. Royal Purple. A model system was developed, whereby branched cuttings could be harvested from stock hedges and manipulated to alter leaf area, the number of actively‐growing, lateral branches and thus the source: sink ratio for photoassimilates. Highest percentage rooting ((80%) was promoted by retention of branches and a full leaf area. Reducing leaf area resulted in a lower rooting percentage (44%); however, greatest reductions in rooting were associated with the removal of lateral branches ((22%). Applying exogenous auxin (indole‐3‐butyric acid) at the excision point where branches had been removed significantly improved rooting potential, but did not fully substitute for the presence of branches with active shoot tips. Negative effects associated with removing a proportion of mature leaves appeared to relate to alterations in carbon balance rather than an influence on the supply of endogenous auxin to the potential rooting zone. The use of branched cuttings accelerated root and shoot development and resulted in a finished plant being produced more rapidly than is achieved from conventional, non‐branched cuttings. The results presented indicate a means for improving the efficiency of production of Cotinus coggygria, which may be applicable to a wider range of ornamental plants.     

In situ evaluation of surface roughness and micromorphology of temporary soft denture liner materials at different time intervals

Objective

To perform an in situ evaluation of surface roughness and micromorphology of two soft liner materials for dentures at different time intervals.

Background

The surface roughness of materials may influence the adhesion of micro‐organisms and inflammation of the mucosal tissues. The in situ evaluation of surface roughness and the micromorphology of soft liner materials over the course of time may present results different from those of in vitro studies, considering the constant presence of saliva and food, the changes in temperature and the pH level in the oral cavity.

Materials and methods

Forty‐eight rectangular specimens of each of the two soft liner materials were fabricated: a silicone‐based material (Mucopren Soft) and an acrylic resin‐based material (Trusoft). The specimens were placed in the dentures of 12 participants (n = 12), and the materials were evaluated for surface roughness and micromorphology at different time intervals: 0, 7, 30 and 60 days. Roughness (Ra) was evaluated by means of a roughness tester. Surface micromorphology was evaluated by scanning electron microscopy.

Results

Analysis of variance for randomised block design and Tukey's test showed that surface roughness values were lower in the groups using the silicone‐based material at all the time intervals (P < .0001). The average surface roughness was higher at time interval 0 than at the other intervals, for both materials (P < .0001). The surface micromorphology showed that the silicone material presented a more regular and smoother surface than the acrylic resin‐based material.

Conclusion

The surface roughness of acrylic resin‐based and silicone‐based denture soft liner materials decreased after 7 days of evaluation, leading to a smoother surface over time. The silicone‐based material showed lower roughness values and a smoother surface than the acrylic resin‐based material, thereby making it preferred when selecting more appropriate material, due its tendency to promote less biofilm build‐up.     

Relining of prosthesis with auto‐polymerizing hard denture reline resins: effect of post‐polymerization treatment on flexural strength

Background: It has been suggested that microwave irradiation and prosthesis immersion in hot water after its polymerization may improve mechanical and viscoelastic properties of acrylic resins. Purpose: This study was proposed to verify the influence of microwave post‐polymerization (PP) treatment over the flexural strength of thermo‐polymerizing acrylic resin specimens (QC‐20) relined or not with two different composition hard chairside auto‐polymerizing reliners [Kooliner (K) and New Truliner (NT)]. Materials and Methods: For this study, 50 specimens of 64 × 10 × 3.3 mm were polymerized and distributed into five groups. G1 (control) specimens without relining and PP; G2 specimens relined with K, without PP; G3 specimens relined with NT, without PP; G4 specimens relined with K, with PP (microwave irradiation with 650 W for 5 min); G5 specimens relined with NT, with PP. Tests were performed on a universal testing machine Instron 4411 with compression speed of 5 mm/min. Results: Specimens of K without PP did not show statistically different results (p < 0.05) when compared with control. However, when submitted to PP these specimens showed a significant increase in flexural strength. Specimens of NT showed the lowest flexural strength of all groups, with or without PP when compared with control and K groups. Conclusion: Microwave PP (650 W for 5 min) proved to be an effective method of improving the flexural strength of K relined prosthesis. However, it did not seem to affect NT specimens.     

Effects of X-irradiation on mitochondrial DNA damage and its supercoiling formation change

There have been a small number of reports of radiation-induced mtDNA damage, and mtDNA supercoiling formation change induced by ionizing radiation has not been investigated before. This study evaluated mtDNA damage and supercoiling formation change after X-irradiation. The human breast cancer cell line, MCF-7 cells were used for analysis. Modified supercoiling-sensitive real-time PCR approach was used to evaluate mitochondrial DNA supercoiling formation change and copy number; long-PCR method was applied for the quantification of mtDNA damage. MtDNA damage and formation change induced by high-dose irradiation was persistent in 24 h after irradiation and was not significant after low-dose irradiation. MtDNA copy number was slightly increased after high-dose irradiation and a transit increase was observed after low-dose irradiation. This is the first study to evaluate radiation-induced mitochondrial DNA supercoiling formation change using real-time PCR. Combined with data of ROS generation and dynamics of mitochondrial mass, our findings suggested that mtDNA is sensitive to radiation hazards, indicating mitochondrial biogenesis play an important role in radiation-induced cellular response.     

Retrospective spatial analysis of the pollination of two miniature epiphytic orchids with different pollination strategies in a coffee plantation in Soconusco,Chiapas, Mexico

Quantitative and spatial data for orchid pollination are scarce and may be important tools for reintroduction and conservation; however, conclusions cannot be drawn on the basis of the typically infrequent and unpredictable pollination events. We carried out a novel, retrospective, spatial analysis of the pollination of the entire population of two miniature orchids, Erycina crista‐galli and Notylia barkeri, on coffee bushes in plantations at 900 m in Soconusco, south‐eastern Mexico. The numbers of mature flowering plants of both species in the experimental site were similar. Notylia barkeri produced nearly four times as many flowers, but a similar proportion of the total number of flowers produced was pollinated (1.23% and 1.48% for N. barkeri and E. crista‐galli, respectively). An estimated 29 919 977 (±4 983 995) seeds were produced by N. barkeri, nearly 12 times more than E. crista‐galli at 1 009 414 (±147 000). The pollinators of N. barkeri chose flower clusters at random and pollinated various flowers within a patch, whereas the pollinators of E. crista‐galli chose patches of flowers slightly more systematically, with less dependence on flower density, and appeared to dedicate less attention to each patch. For both species, pollinators slightly favoured larger clusters of flowers and left many individual and groups of flowers unvisited. To restore populations of these orchids in coffee plantations as a replacement habitat, N. barkeri should be planted in small, separate groups and E. crista‐galli in larger groups of individuals, dispersed regularly throughout the selected site to maximize the possibility that the flowers will be discovered by pollinators. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 448–459.