138 research outputs found
The effect of zirconia surface treatment on bond strength of various cement systems
OBJECTIVES: The aim of this in-vitro study is to evaluate the effect of different zirconia surface pretreatments, different cement types and the effect of accelerated aging on the adherence of bonding cements to zirconia.
MATERIALS AND METHODS: 64 zirconia 3Y-TZP tapered rings were pressed from TZ-3YSB-E zirconia powder, pre-treated with different surface treatments, then cemented to titanium abutment pins using 8 different cements: Maxcem Elite chroma (Kerr), TheraCem (Bisco), RelyX Unicem2 (3M ESPE), Multilink Automix (Ivoclar Vivadent), Panavia SA Cement Plus (Kuraray), Ceramir C&B (Doxa), CemEZ Universal (Zest Dental), and Bifix SE (VOCO). The partitally sintered zirconia specimens were divided according to design of experment (DOE). Zirconia surface treatments: 1) control group with no surface treatment, 2) airborne particle abrasion of fully sintered zirconia ring (FS-APA50), 3) airborne particle abrasion of partially sintered zirconia (PS-APA50), 4) tribochemical silica coating of fully sintered zirconia (FS-CoJet30), 5) tribochemical silica coating of partial sintered zirconia (PS-CoJet30), and 6) nano-structured alumina coating of fully sintered zirconia (NanoAl). Zirconia rings were subjected to post-treatment:1) control 24h incubation after cementing proceedure, and 2) accelerated aging . The pull-out axial tensile retention load was tested using an Instron Model 5566A. Multi factorial linear regression model (JMP Pro 15) was used for data analysis (α=0.05).
RESULTS: The retention force (N) of zirconia rings to titanium abutment pins was evaluated using a pull-out test. Four key factors were investigated in this study: zirconia surface pre-treatment, cement type, post-treatment and firing effect. There was a significant effect of zirconia surface pre-treatment on retention force (nano-structured alumina coating ≥ tribochemical abrasion = airborne-particle abrasion ≥ control). There was a significant effect of cement type on retention force [Multilink AM ≥ (Cem EZ = TheraCem = Panivia SA = RelyX Unicem2 = BiFix) ≥ Ceramir CB = Maxcem Elite]. There is a significant difference in retention strength to zirconia among post-treatment effect, with accelerated aging groups achieving slightly higher bond strength than 24h water storage groups.
CONCLUSIONS: Significant different retention loads were found among tested groups. Nano-structured alumina coating surface pre-treatment has significantly higher bond strength than other treatments. Some cement systems with functional monomer had significant higher bond strengths
Thermal comfort properties of wool and polyester/wool woven fabrics dyed in black
An abaya is a traditional Muslim woman's outer garment. It is black and worn on a day-to-day basis when women are outside their homes. The abaya absorbs most of the heat from sunlight in a hot climate as it is black, making the wearer very uncomfortable. In order to reduce absorption of heat in an abaya and to make the wearer more comfortable, it is proposed that a treatment with a solar energy re°ector could enable the wearer to perspire less; thus allowing them to feel cooler. This paper investigates the thermal comfort properties of plain-woven fabrics dyed in black and treated chemically to re°ect a proportion of sunlight's energy. The fabrics were made from 100% wool and two polyester/wool blends. The testing results showed that the fabrics that had received the re°ective treatment possessed marginally improved thermal comfort properties as compared to fabrics without the treatment
Microbiome structure and response to watering in rhizosphere of Nitrosalsola vermiculata and surrounding bulk soil
The plant rhizosphere microbiomes were thought to help the plant stands adverse condition. The study aims at deciphering signatures of rhizosphere soil microbiomes of the medicinal plant Nitrosalsola vermiculata and those of the surrounding bulk soil as well as to detect influence of watering in restructuring soil microbes that can improve the plant’s ability to tolerate drought stress. Amplicon sequencing of partial 16S rRNA gene indicated that alpha diversity indices are higher in rhizosphere than in bulk soils, while no distinctive differences were observed due to the watering. Relative abundance of phylum Cyanobacteria and its descendent unidentified genus is the highest among phyla and genera of bulk soil. Relative abundance of phyla Euryarchaeota, Chloroflexi, Actinobacteria, Proteobacteria, Bacteroidetes, Firmicutes, Acidobacteria and Gemmatimonadetes as well as genera Bacillus, Ammoniphilus, Sphingomonas, Microvirga, Pontibacter, Adhaeribacter and Arthrobacter was significantly higher in rhizosphere soil. The latter taxa were reported to act as plant growth-promoting bacteria (PGPB) through symbiotic associations. We speculate that relative abundance and mutual dominance of these taxa in rhizosphere of N. vermiculata were due to the intensity and type of plant root exudates. Other factors include soil pH where microbes favoring high soil pH can show better growth in rhizosphere soil. Also, co-existence of phyla that promote sustainability of cohabiting phyla in the rhizosphere and have high synergism prevalence in biofilm formation can be one extra factor. Quorum sensing (QS) also mediates bacterial population density in a given environment and elicit specific plant responses. The low abundance of Cyanobacteria in rhizosphere soil can be due to the inhibitory effect of highly abundant members of Firmicutes, especially those of genus Bacillus. The latter conclusion was confirmed by the occurrence of high expression rate of comQ gene triggering QS in genus Bacillus. Highly abundant microbes whose abundance was not changed due to watering are phyla Firmicutes, Proteobacteria, Chloroflexi and Cyanobacteria and their descendent genera Bacillus, Ammoniphilus, Sphingomonas, Microvirga and unidentified genus of Cyanobacteria. We speculate that non-responsive taxa to watering were drought tolerant and can help plants stand adverse conditions of water scarce. In conclusion, insights on the factors involved in shaping microbiome signatures and those eliciting differential plant responses to drought stress are raised and warrant further investigations
Pre-mRNA splicing repression triggers abiotic stress signaling in plants
[EN] Alternative splicing (AS) of precursor RNAs enhances transcriptome plasticity and proteome diversity in response to diverse growth and stress cues. Recent work has shown that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various inhibitors of AS. Here, we show that the macrolide pladienolide B (PB) inhibits constitutive splicing and AS in plants. Also, our RNA sequencing (RNA-seq) data revealed that PB mimics abiotic stress signals including salt, drought and abscisic acid (ABA). PB activates the abiotic stress-and ABA-responsive reporters RD29A::LUC and MAPKKK18::uidA in Arabidopsis thaliana and mimics the effects of ABA on stomatal aperture. Genome-wide analysis of AS by RNA-seq revealed that PB perturbs the splicing machinery and leads to a striking increase in intron retention and a reduction in other forms of AS. Interestingly, PB treatment activates the ABA signaling pathway by inhibiting the splicing of clade A PP2C phosphatases while still maintaining to some extent the splicing of ABA-activated SnRK2 kinases. Taken together, our data establish PB as an inhibitor and modulator of splicing and a mimic of abiotic stress signals in plants. Thus, PB reveals the molecular underpinnings of the interplay between stress responses, ABA signaling and post-transcriptional regulation in plants.We wish to thank members of the Laboratory for Genome Engineering at King Abdullah University of Science and Technology for helpful discussions and comments on the manuscript. We wish to thank Moussa Benhamed for helpful discussions and suggestions and for providing key materials. We wish to thank Sean Cutler for providing Arabidopsis seeds of MAKPKKK18-uidA. This study was supported by King Abdullah University of Science and Technology. Work in PR's laboratory was funded by grant BIO2014-52537-R from MINECO. Work in PD's laboratory is funded by grant PTDC/BIA-PLA/1084/2014 from FCT. The authors declare no conflicts of interest.Ling, Y.; Alshareef, S.; Butt, H.; Lozano Juste, J.; Li, L.; Galal, AA.; Moustafa, A.... (2017). Pre-mRNA splicing repression triggers abiotic stress signaling in plants. The Plant Journal. 89(2):291-309. https://doi.org/10.1111/tpj.13383S29130989
Surgical Approaches to Congenital Anomalies of Esophagus
With prevalence of about 1 in 3000 live births, pediatric surgeons commonly deal with esophageal abnormalities, which may provide substantial clinical complications. Surprisingly, the embryologic processes underlying esophageal atresia (EA) with or without tracheoesophageal fistula (TEF), one of the hallmark disease entities of pediatric surgery, have only lately been largely uncovered. When it comes to the treatment of congenital esophageal abnormalities, notably esophageal atresia and tracheoesophageal fistula, surgical methods are essential. In order to address the anatomical abnormalities and restore normal function, surgical correction is often necessary in the care of congenital esophageal anomalies, including esophageal atresia and tracheoesophageal fistula. In this review we are going to cover surgical approaches to repair those malformations, long-term outcomes, and latest developments in esophageal surgical approaches
Pre-mRNA splicing repression triggers abiotic stress signaling in plants
Alternative splicing (AS) of precursor RNAs enhances transcriptome
plasticity and proteome diversity in response to diverse growth and
stress cues. Recent work showed that AS is pervasive across plant
species, with more than 60% of intron-containing genes producing
different isoforms. Mammalian cell-based assays have discovered various
AS inhibitors. Here, we show that the macrolide Pladienolide B (PB)
inhibits constitutive splicing and AS in plants. Also, our RNA-seq data
revealed that PB mimics abiotic stress signals including salt, drought,
and abscisic acid (ABA). PB activates the abiotic stress- and
ABA-responsive reporters RD29A::LUC and MAPKKK18::GUS in Arabidopsis thaliana
and mimics the effects of ABA on stomatal aperture. Genome-wide
analysis of AS by RNA-seq revealed that PB perturbs the splicing
machinery and leads to a striking increase in intron retention and a
reduction in other forms of AS. Interestingly, PB treatment activates
the ABA signaling pathway by inhibiting the splicing of clade A PP2Cs
phosphatases while still maintaining to some extent the splicing of
ABA-activated SnRK2 kinases. Taken together, our data establish PB as an
inhibitor and modulator of splicing and a mimic of abiotic stress
signals in plants. Thus, PB reveals the molecular underpinnings of the
interplay between stress responses, ABA signaling, and
post-transcriptional regulation in plants.</p
An exploration of the determinants for decision to migrate existing resources to cloud computing using an integrated TOE-DOI model
Migrating existing resources to cloud computing is a strategic organisational decision that can be difficult. It requires the consideration and evaluation of a wide range of technical and organisational aspects. Although a significant amount of attention has been paid by many industrialists and academics to aid migration decisions, the procedure remains difficult. This is mainly due to underestimation of the range of factors and characteristics affecting the decision for cloud migration. Further research is needed to investigate the level of effect these factors have on migration decisions and the overall complexity. This paper aims to explore the level of complexity of the decision to migrate the cloud. A research model based on the diffusion of innovation (DOI) theory and the technology-organization-environment (TOE) framework was developed. The model was tested using exploratory and confirmatory factor analysis. The quantitative analysis shows the level of impact of the identified variables on the decision to migrate. Seven determinants that contribute to the complexity of the decisions are identified. They need to be taken into account to ensure successful migration. This result has expanded the collective knowledge about the complexity of the issues that have to be considered when making decisions to migrate to the cloud. It contributes to the literature that addresses the complex and multidimensional nature of migrating to the cloud
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