The Micro-Shear bond strength of different cements to commercially pure titanium

The most appropriate luting agent for attaching the prefabricated Ti-based insert of hybrid abutments to its ceramic component has not yet been determined. This study was done aimed at examining the micro-shear bond strength (?SBS) of different cements to commercially pure titanium (Cp Ti). A total of 100 milled cubes of Cp Ti was airborne-particle abraded using 250 ?m aluminum oxide particles. Specimens were then divided into 5 groups (n=20) according to the type of resin cement used: (1) Panavia F.2, (2) Rely X U200, (3) Panavia SA LUTING Plus, (4) GC Fuji I, and (5) GC FujiCEM 2. After 24h storage, half of the samples were subjected to 5000 cycles of thermal aging. Next, the bonded samples were tested in the micro-shear mode. Data (MPa) were analyzed using a two-way ANOVA and the post hoc Tukey test (?=0.05). After debonding, each sample was examined for the failure mode classification. The highest ?SBS value in the study cements was obtained for Panavia F.2 cement (P<0.001) with no significant difference with Rely X U200 (P=0.07). The ?SBS values of both GI-based cements were significantly lower than those of resin cements. Thermal aging decreased the ?SBS values of all groups (P=0.003) significantly. The mainly occurred failure mode in all groups was the adhesive feature. Resin cements demonstrated acceptable bonding to Cp Ti, yet Gl-based cements did not. From among the cements examined, Panavia F.2 can be considered as the best option for bonding to Ti

Murine Trophoblast Stem Cells and Their Differentiated Cells Attenuate Zika Virus In Vitro By Reducing Glycosylation of the Viral Envelope Protein

Zika virus (ZIKV) infection during pregnancy can cause devastating fetal neuropathological abnormalities, including microcephaly. Most studies of ZIKV infection in pregnancy have focused on post-implantation stage embryos. Currently, we have limited knowledge about how a pre-implantation stage embryo deals with a viral infection. This study investigates ZIKV infection on mouse trophoblast stem cells (TSCs) and their in vitro differentiated TSCs (DTSCs), which resemble the cellular components of the trophectoderm layer of the blastocyst that later develops into the placenta. We demonstrate that TSCs and DTSCs are permissive to ZIKV infection; however, ZIKV propagated in TSCs and DTSCs exhibit substantially lower infectivity, as shown in vitro and in a mouse model compared to ZIKV that was generated in Vero cells or mouse embryonic fibroblasts (MEFs). We further show that the low infectivity of ZIKV propagated in TSCs and DTSCs is associated with a reduced level of glycosylation on the viral envelope (E) proteins, which are essential for ZIKV to establish initial attachment by binding to cell surface glycosaminoglycans (GAGs). The decreased level of glycosylation on ZIKV E is, at least, partially due to the low-level expression of a glycosylation-related gene, Hexa, in TSCs and DTSCs. Furthermore, this finding is not limited to ZIKV since similar observations have been made as to the chikungunya virus (CHIKV) and West Nile virus (WNV) propagated in TSCs and DTSCs. In conclusion, our results reveal a novel phenomenon suggesting that murine TSCs and their differentiated cells may have adapted a cellular glycosylation system that can limit viral infectivity by altering the glycosylation of viral envelope proteins, therefore serving as a unique, innate anti-viral mechanism in the pre-implantation stage embryo

Dicer Represses the Interferon Response and the Double-Stranded RNA-Activated Protein Kinase Pathway In Mouse Embryonic Stem Cells

Recent studies have demonstrated that embryonic stem cells (ESCs) are deficient in expressing type I interferons (IFN), the cytokines that play key roles in antiviral responses. However, the underlying molecular mechanisms and biological implications of this finding are poorly understood. In this study, we developed a synthetic RNA-based assay that can simultaneously assess multiple forms of antiviral responses. Dicer is an enzyme essential for RNA interference (RNAi), which is used as a major antiviral mechanism in invertebrates. RNAi activity is detected in wild-type ESCs but is abolished in Dicer knockout ESCs (D-/-ESCs) as expected. Surprisingly, D-/-ESCs have gained the ability to express IFN, which is otherwise deficient in wild-type ESCs. Furthermore, D-/-ESCs have constitutively active double-stranded RNA (dsRNA)-activated protein kinase (PKR), an enzyme that is also involved in antiviral response. D-/-ESCs show increased sensitivity to the cytotoxicity resulting from RNA transfection. The effects of dsRNA can be partly replicated with a synthetic B2RNA corresponding to the retrotransposon B2 short interspersed nuclear element. B2RNA has secondary structure features of dsRNA and accumulates in D-/-ESCs, suggesting that B2RNA could be a cellular RNA that activates PKR and contributes to the decreased cell proliferation and viability of D-/-ESCs. Treatment of D-/-ESCs with a PKR inhibitor and IFNβ-neutralizing antibodies increased cell proliferation rate and cell viability. Based on these findings, we propose that, in ESCs, Dicer acts as a repressor of antiviral responses and plays a key role in the maintenance of proliferation, viability, and pluripotency of ESCs

Biogeographic classification of the Caspian Sea

Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during recent decades, yet the scientific understanding of this water body remains poor. In this study, an eco-geographical classification of the CS based on physical information derived from space and in situ data is developed and tested against a set of biological observations. We used a two-step classification procedure, consisting of (i) a data reduction with self-organizing maps (SOMs) and (ii) a synthesis of the most relevant features into a reduced number of marine ecoregions using the hierarchical agglomerative clustering (HAC) method. From an initial set of 12 potential physical variables, 6 independent variables were selected for the classification algorithm, i.e., sea surface temperature (SST), bathymetry, sea ice, seasonal variation of sea surface salinity (DSSS), total suspended matter (TSM) and its seasonal variation (DTSM). The classification results reveal a robust separation between the northern and the middle/southern basins as well as a separation of the shallow nearshore waters from those offshore. The observed patterns in ecoregions can be attributed to differences in climate and geochemical factors such as distance from river, water depth and currents. A comparison of the annual and monthly mean Chl <i>a</i> concentrations between the different ecoregions shows significant differences (one-way ANOVA, <i>P</i> < 0.05). In particular, we found differences in phytoplankton phenology, with differences in the date of bloom initiation, its duration and amplitude between ecoregions. A first qualitative evaluation of differences in community composition based on recorded presence–absence patterns of 25 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics

The Hydraulic Investigation of Perforated-Cylindrical-Intake Structure

ABSTRACT: Water surface level regulation and deviation of a constant value of discharge into the side channel, is the basis of the intake systems in irrigation channels, considering the main discharge rate fluctuates during the seasons. Hence, the necessity to design a structure which can control the consequences of discharge fluctuation in main channel and divert the constant value of demand water flow is more recognizable. The perforated-cylindrical-intake instrument is a new model of regulatorintake function, includes a free overflow on a cylindrical weir associated with intake element that can fulfil the main objective of a regulator and an intake devices, simultaneously. This research firstly, examined the different geometric conditions of the structure and determined the best one, then, tried to investigate the hydraulic function, operation method and the correlation of the intake discharge and upstream flow depth versus the discharge of the main channel in various condition of the structure based on an experimental work. The results show that in wide range of discharge variation in the main channel, the intake discharge variation were not considerable, also, it would be possible to measure and control the intake discharge precisely, installing a counter and a valve at the side channel

Detection and Verification of Mammalian Mirtrons by Northern Blotting

microRNAs (miRNAs) have vital roles in regulating gene expression—contributing to major diseases like cancer and heart disease. Over the last decade, thousands of miRNAs have been discovered through high throughput sequencing-based annotation. Different classes have been described, as well as a great dynamic range of expression levels. While sequencing approaches provide insight into biogenesis and allow confident identification, there is a need for additional methods for validation and characterization. Northern blotting was one of the first techniques used for studying miRNAs, and remains one of the most valuable as it avoids enzymatic manipulation of miRNA transcripts. Blotting can also provide insight into biogenesis by revealing RNA processing intermediates. Compared to sequencing, however, northern blotting is a relatively insensitive technology. This creates a challenge for detecting low expressed miRNAs, particularly those produced by inefficient, non-canonical pathways. In this chapter, we describe a strategy to study such miRNAs by northern blotting that involves ectopic expression of both miRNAs and miRNA-binding Argonaute (Ago) proteins. Through use of epitope tags, this strategy also provides a convenient method for verification of small RNA competency to be loaded into regulatory complexes

Einfluss kognitiver und emotionaler Störungen auf die subjektive Erwerbsprognose und Arbeitsfähigkeit bei Multipler Sklerose am Ende der medizinischen Rehabilitation

Der Einfluss kognitiver und emotionaler Störungen auf die subjektive Erwerbsprognose und Arbeitsfähigkeit wurde bei 50 Patienten mit Multipler Sklerose (MS) im Rehabilitations-(Reha)-verlauf über Fragebögen sowie psychologische Testverfahren analysiert. Es konnte eine signifikante Verbesserung der subjektiven Prognose der Erwerbstätigkeit und Arbeitsfähigkeit am Reha-Ende festgestellt werden. Dabei profitierten MS-Patienten, die an Depressionen und Angststörungen litten, deutlich stärker von der Reha als Patienten mit ausgeprägter Fatigue- Symptomatik. Ebenso verbesserte sich die Kognition der Patienten im Reha-Verlauf. Die Ergebnisse der vorliegenden Studie belegen, dass emotionale Störungen und kognitive Defizite wichtige Einflussgrößen für die Prognose der Erwerbstätigkeit sind. Um den Reha-Erfolg von Patienten mit subjektiver Gefährdung der Erwerbstätigkeit und Arbeitsfähigkeit zu verbessern, sollten die psychischen Beeinträchtigungen durch die MS-Erkrankung sowohl zum Reha-Beginn als auch im weiteren Verlauf berücksichtigt werden. Dafür sind spezifische Assessments und Interventionen empfehlenswert

Characterization of Innate Immune Responses in Mouse Trophoblast Stem Cells and Their Differentiated Cells

The blastocyst is the preimplantation stage embryo consisting of two major components: the inner cell mass (ICM) and the trophectoderm (TE). The ICM forms the fetus, whereas the TE contributes to the placenta development. Previous studies have demonstrated that human and mouse embryonic stem cells (ESCs) derived from the ICM are deficient in expressing type I IFNs in response to viral infection. This study investigated the innate immune responses in mouse trophoblast stem cells (TSCs) and their in vitro differentiated trophoblasts (TSC-TBs). I report that, unlike ESCs, TSCs have a functional IFN system. They can express and respond to type I IFNs and provide ESCs with antiviral activity against Chikungunya and Zika virus infection. Our data demonstrate that mouse ESCs can respond to type I IFNs and gain IFN-based antiviral protection from TSCs and TSC-TBs via paracrine signaling mechanisms, even though they cannot express type I IFNs. TNF⍺ and IFN play an important role in successful implantation. However, the combination of these cytokines can cause cytotoxicity in most of the cells through inducible nitric oxide synthase (iNOS) expression; ESCs are less susceptible to their cytotoxicity due to their lack of ability to express iNOS. Nevertheless, ESCs are sensitive to the cytotoxicity of nitric oxide (NO) in vitro, suggesting that NO can be detrimental to ESCs in the blastocyst cavity if an excessive amount is released from TSCs and TSC-TBs. Interestingly, our data also revealed that, like ESCs, TSCs and TSC-TBs are insensitive to the cytotoxicity of TNFα/IFNγ and do not express iNOS. We analyzed the responses of TSCs and TSC-TBs and mouse embryonic fibroblasts (MEFs) to TNFα, IFNγ, and TNFα/IFNγ with different experimental approaches. We have compared TSCs and TSC-TBs responses with MEFs, which strongly respond to TNFα and IFNγ and express iNOS. Our results show that IFN can weakly activate JAK/STAT1 pathway, and TNF⍺ fails to activate the NFκB pathway in TSCs and TSC-TBs, which explains the lack of inflammatory genes and iNOS induction in these cells. Our studies may provide a critical, new approach to defining the molecular properties of TE cells after in vivo exposure to cytokines or pathogens during implantation