Influence of ceramic (feldspathic) surface treatments on the micro-shear bond strength of composite resin

Objective: To test the null hypothesis that surface treatment has no influence on the micro-shear bond strength between orthodontic composite resin cement and ceramics (feldspathic porcelain). Materials and Methods: Circular specimens of feldspathic porcelain were fabricated and randomly divided into six groups: (1) no treatment; (2) treatment with a mixture of acidic primer and silane agent for 20 seconds; (3) etching with 9.5% hydrofluoric acid; (4) etching with 9.5% hydrofluoric acid and coating with a mixture of acidic primer and silane agent for 20 seconds; (5) airborne-particle abrasion with 50-μm aluminum oxide; and (6) airborne-particle abrasion and coating with a mixture of acidic primer and silane agent for 20 seconds. The porcelain disks were then bonded to resin cylinders with composite resin cement. A micro-shear bond test was carried out to measure the bond strength. Moreover, each ceramic surface was observed morphologically by scanning electron microscopy. One-way analysis of covariance was used to compare the groups for differences in micro-shear bond strength. Results: The mean micro-shear bond strength varied as a function of surface treatment. It ranged from 3.7 to 20.8 MPa. The highest values for micro-shear bond strength were found when the surface was acid-etched with hydrofluoric acid and coated with silane. On the other hand, the control group (no treatment) had significantly lower micro-shear bond strength than all the other groups. Conclusion: The null hypothesis that the surface treatment has no influence on the micro-shear bond strength of orthodontic composite resin was rejected. The bond strength between ceramics and orthodontic resin cement is affected by the ceramic surface treatment. The bond failure was of the adhesive type, except with the hydrofluoric acid + silane group, where it was a cohesive bond failure

Mechanical And Physical Properties of Wood-Plastic Composites Made of Polypropylene, Wood Flour and Nanoclay

The focus of this study was to characterize mechanical and physical properties of experimental composition prepared from nanoclays (Cloisite® 20A), wood flour (WF) and polypropylene (PP). Nanoclays with different concentrations were used as reinforcing filler for wood plastic compositions (WPCs). Maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent to increase the interaction between the components of wood-plastic composites. Nanoclay based wood-plastic composites were made by extrusion process and then injection molding. Mechanical and physical properties of the as-prepared composites were evaluated. The results of strength measurements showed that the flexural modulus of the composite was increased by 56.33 % with increasing of nanoclays contents to 5 wt. %, reaching approximately 3.58 GPa compared to WPC containing 0% of nanoclays. Moreover, the flexural and tensile strengths reached their maximum values when the concentrations of nanoclays was 2.5 wt. %. When maintaining the nanoclays at a low concentration, it was well dispersed in the WPC. However, when more nanoclays (4 –5 wt. %) was introduced, the enhancing effect began to diminish because of the agglomeration of nanoclays which caused poor interfacial adhesion. The addition of nanoclays decreased the average water uptake by 13 %, compared to the control sample (without nanoclays). The improvement of physical and mechanical properties confirmed that nanoclays has good reinforcement and the optimum effect of nanoclays was archived at 2.5 wt. %

Association analysis for yield and related traits in fenugreek (Trigonella foenum-graecum L.) under different environmental conditions

Sixteen diverse genotypes of fenugreek (Trigonella foenum-graecum L.) were grown in five (E1 to E5) environments which were created by different date of sowing during the rabi seasons at the Vegetable Farm of CCS HAU, Hisar. (29°15?N, 75°69?E) during 2012-13. Observations were recorded on ten randomly selected plants from each genotypes in each replications for characters viz. field emergence index, days to 50 % flowering, plant height, number of pods per plant, number of branches per plant, number of seeds per pod, pod length, seed yield (q/ha), test weight, seed germination, seed vigour index-I and II. The estimation of genotypic and phenotypic coefficients (GCV and PCV) variation in all the environments was consistently decreasing with the delaying in sowing date for all the character studied except plant height and test weight indicating that the environmental influence was comparatively more pronounced for these characters in expressing the phenotypic performance of different genotypes. Highest GCV and PCV was estimated as 50.36 % and 55.93 %, respectively for seed vigour index-I in E1. High value of heritability estimated for characters seed yield, seed vigour index-II, seed germination and branches per plant (above 70 %) in E1 revealed that these were less influenced by environment and low heritability estimated for days to 50 % flowering in E2, plant height in E2, seeds per pod in E3, field emergence index in E5 indicated high influence of environment. Based on environmental indices, the environment E2 was most favourable for all the characters studied except field emergence index

Cell and matrix response of temporomandibular cartilage to mechanical loading

OBJECTIVES: The generation of transgenic mice expressing green fluorescent proteins (GFPs) has greatly aided our understanding of the development of connective tissues such as bone and cartilage. Perturbation of a biological system such as the temporomandibular joint (TMJ) within its adaptive remodeling capacity is particularly useful in analyzing cellular lineage progression. The objectives of this study were to determine: (i) if GFP reporters expressed in the TMJ indicate the different stages of cell maturation in fibrocartilage and (ii) how mechanical loading affects cellular response in different regions of the cartilage. DESIGN/METHODS: Four-week-old transgenic mice harboring combinations of fluorescent reporters (Dkk3-eGFP, Col1a1(3.6 kb)-GFPcyan, Col1a1(3.6 kb)-GFPtpz, Col2a1-GFPcyan, and Col10a1-RFPcherry) were used to analyze the expression pattern of transgenes in the mandibular condylar cartilage (MCC). To study the effect of TMJ loading, animals were subjected to forced mouth opening with custom springs exerting 50 g force for 1 h/day for 5 days. Dynamic mineralization and cellular proliferation (EdU-labeling) were assessed in loaded vs control mice. RESULTS: Dkk3 expression was seen in the superficial zone of the MCC, followed by Col1 in the cartilage zone, Col2 in the prehypertrophic zone, and Col10 in the hypertrophic zone at and below the tidemark. TMJ loading increased expression of the GFP reporters and EdU-labeling of cells in the cartilage, resulting in a thickness increase of all layers of the cartilage. In addition, mineral apposition increased resulting in Col10 expression by unmineralized cells above the tidemark. CONCLUSION: The TMJ responded to static loading by forming thicker cartilage through adaptive remodeling

Detecting Sentiments from Movie Reviews by Integrating Reviewers Own Prejudice

Presently, sentiment analysis algorithms are widely used to extract positive or negative feedback scores of various objects on the basis of the text/reviews. But, an individual may have a certain degree of biasness towards a certain product/company and hence may not objectively review the object. We try to combat this biasness problem by incorporating the positive and negative bias component in the existing sentiment score of the object. This paper proposes several algorithms for a new system of implementing individual bias in the corpus of data i.e. movie reviews in this case. Each review comment has an unadjusted sentiment score associated with it. This unadjusted score is refined to give an adjusted score using the positive and negative bias score. The bias score is calculated using certain parameters, the weightage of which has been determined by conducting a survey. We lay emphasis on the degree of biasness an individual has towards or against the review parameters for the movie reviews corpus namely actor, director and genre. We equip the system with the capability to handle various scenarios like positive inclination of the user, negative inclination of the user, presence of both positive and negative inclination of the user and neutral attitude of the user by implementing the formulae we developed

Recent research and developments of degradation assessment and its diagnosis methods for solar PV plant: a review

The world is moving forward to a transition in the form of increasing the contribution of renewable energy sources in the energy sector, and among these, solar photovoltaic-based power generation is catching pace. Several factors are responsible for the lowering of outputs due to different degradation causes such as hotspots, corrosion, humidity, ultraviolet (UV) irradiation, temperature effects, dust, aging, weathering, yellowing, snail trails, discoloration, junction box failure, delamination, cracks, and faults from the solar photovoltaic (PV) plants. This paper presents a comprehensive review of the various form of degradation and their implications on solar PV power plant performance. The review has been carried out considering the different degradation causes and their identification methods in solar PV plant. Further, the analysis has been done on the basis of the earlier studies to understand the rates of degradation for various solar PV power plants in various climatic conditions. The PV technologies used in solar power plants are also responsible for the change in the performance of power plants over time; therefore, degradation based on different solar PV cell technologies is also analyzed. The visual inspection tools like thermal imaging with IR cameras help identify areas with abnormal heat patterns, indicating potential issues like cell or interconnect failures, loose electrical connections, or bypass diode malfunctions while EL cameras are used to identify low-level electrical excitation and defects such as cracks, hotspots, and cell-level degradation