Laminar Flow Chamber Research Articles

Fibronectin induces a transition from amoeboid to a fan morphology and modifies migration in Entamoeba histolytica.

Cell migration modes can vary, depending on a number of environmental and intracellular factors. The high motility of the pathogenic amoeba Entamoeba histolytica is a decisive factor in its ability to cross the human colonic barrier. We used quantitative live imaging techniques to study the migration of this parasite on fibronectin, a key tissue component. Entamoeba histolytica amoebae on fibronectin contain abundant podosome-like structures. By using a laminar flow chamber, we determined that the adhesion forces generated on fibronectin were twice those on non-coated glass. When migrating on fibronectin, elongated amoeboid cells converted into fan-shaped cells characterized by the presence of a dorsal column of F-actin and a broad cytoplasmic extension at the front. The fan shape depended on the Arp2/3 complex, and the amoebae moved laterally and more slowly. Intracellular measurements of physical variables related to fluid dynamics revealed that cytoplasmic pressure gradients were weaker within fan-shaped cells; hence, actomyosin motors might be less involved in driving the cell body forward. We also found that the Rho-associated coiled-coil containing protein kinase regulated podosome dynamics. We conclude that E. histolytica spontaneously changes its migration mode as a function of the substrate composition. This adaptive ability might favour E. histolytica's invasion of human colonic tissue. By combining microfluidic experiments, mechanical modelling, and image analysis, our work also introduces a computational pipeline for the study of cell migration.

Micropropagation of Two Varieties of Vitis vinifera Cabernet Franc and Pinot Noir, Comparison of Physiological and Production Parameters

Grapevine (Vitis vinifera) is considered one of the most important fruit crops in the world, and the Cabernet Franc and Pinot Noir varieties have high commercial value. The aim of this study was to compare the in vitro performance of both varieties from explant establishment to in vitro rooting, testing different hormone concentrations. It started from mother plants obtained in vitro, from which uninodal cuttings were taken for micropropagation. Disinfection consisted of washing with 70% alcohol and 20% sodium hypochlorite, with sterile water rinses. Explants were placed in a laminar flow chamber under aseptic conditions in a sterile growth medium. They were grown in a culture chamber with 16 hours of light: 8 hours of darkness and a temperature of 25°C. Establishment, growth, rooting and contamination data were recorded for eight weeks. The culture media used were Experiment 1: 50% Murashige and Skoog (MS) [1] medium; Experiment 2: MS at 50% plus indoleacetic acid (IAA) at 0.01%. The data were statistically analyzed; Cabernet Franc and Pinot Noir had similar production standards, high vigor, good in vitro growth and direct rooting. Both varieties performed better on the auxin enriched medium.

Antibacterial and antifungal activity of curcumin and methylene blue associated with laser on bacterial and fungal strains

Objective: To analyze the effect of methylene blue and 10% curcumin in fungi and bacteria through an in vitro study using photodynamic therapy (PDT). Methods: Curcumin and methylene blue were photosensitized by a Photon Lase III laser applied for 90 s in a dark environment within a laminar flow chamber. Enterococcus faecalis and Candida albicans strains were cultured and standardized. Then, a minimum inhibitory concentration (MIC) assay was conducted for these photosensitizers, with concentration variations and incubation to evaluate their antimicrobial activity. Results: With PDT, Curcumin had significant antibacterial activity against E. faecalis (MIC = 250 µg/mL). In contrast, methylene blue had antibacterial activity against E. faecalis (MIC < 12.5 µg/mL with PDT) and antifungal activity against C. albicans (MIC <12.5 µg/mL with or without PDT). Both agents showed greater efficacy in the presence of the laser. The results suggest that curcumin and methylene blue associated with laser may effectively treat microbial infections. Conclusion: Further research is needed to evaluate the efficacy and safety of using these agents in animal and human models and their effectiveness against different bacterial and fungal strains.

Investigating best practice for specimen preparation for biological testing of root canal sealers

IntroductionBiological characterization of root canal sealers is important as it assesses the ability of the root canal sealer to exert antimicrobial properties thus avoiding treatment failures caused by microbial challenge and also assess the cytotoxic effect on the periapical tissues. Assessment of the biological testing of root canal sealers necessitates the sterilisation of the materials prior to evaluation. This study aims to analyse the influence of various sterilisation techniques conducted prior to biological testing on the microstructure and surface properties of endodontic sealers. Assessment of the initial microbial contamination on the material was also undertaken. MethodsFour commercial sealers were investigated. The sealers were either prepared in a laminar flow cabinet or on a laboratory bench top under ambient conditions. Each group was further divided into 5 groups (n = 3) based on the sterilization technique:1) ethanol-10 mins, 2) ultraviolet-1 h, 3) ethanol-10 mins + ultraviolet-1 h, 4) autoclave, and 5) no sterilisation (control). Microbial levels in the materials were assessed by plate streaking technique. The materials were characterized by scanning electron microscopy and energy dispersive spectroscopy, and Fourier transform infrared spectroscopy, before and after sterilisation, to assess any changes in microstructure and chemical composition. ResultsAll the materials did not exhibit contamination when prepared in laminar flow chamber in sterile conditions compared with sealers prepared on the bench top. Three of the commercial materials showed changes in microstructure while one (TotalFill) was not affected by the sterilisation. AH Plus and BioRoot RCS exhibited alterations in water and alcohol peaks in FT-IR while the single syringe sealers (TotalFill and BioRoot Flow) showed no changes. ConclusionsSterilisation methods cause physical and chemical alterations to sealers. Material preparation should be performed in a laminar flow cabinet and a test for sterility should be performed prior to any biological testing being undertaken. If the materials are not sterile, assessment of the effects of the sterilization methods is recommended.

Designing Ex Situ Conservation Strategies for Butia capitata [Mart. (Becc.) Arecaceae], a Threatened Palm Tree from Brazilian Savannah Biome, through Zygotic Embryo Cryopreservation

Jelly palm (Butia capitata) is a species of palm tree endemic to the Brazilian Savannah (Cerrado) Biome, which stands out for its use as food, which has resulted in a predatory exploitation of its natural populations. This study aimed to characterize fruits and diaspores of natural populations of jelly palm (‘Arinos’, ‘Mirabela’ and ‘Serranópolis’), in addition to developing ex situ conservation strategies of the species, through the storage of zygotic embryos at ultra-low temperatures of liquid nitrogen (LN). Initially, fruits, seeds and embryos were evaluated for their morphological characteristics. For conservation, hydrated zygotic embryos were desiccated for up to 12 h in a laminar-flow chamber and immersed directly in LN with different moisture contents. As a result, we observed morphological differences among the studied populations. The population ‘Arinos’ showed more expressive results for most of the evaluated characteristics, such as length, width of fruits and seeds. The cryopreservation of zygotic embryos proved to be efficient for the conservation of the species reaching germination rates between 70 and 86%, when the moisture content of the embryos immersed in LN were between 10 and 14%. The plants that reached the stage of the greenhouse had a rate of more than 80% survival. The variability in the characteristics of fruits and diaspores of the analyzed populations allow for establishing divergent groups for the definition of conservation strategies or genetic improvement. The developed cryopreservation protocol can be considered simple and efficient for the conservation of the genetic variability of the species.

Precise Nursing of Six Patients Who Underwent Second Allogeneic Hematopoietic Stem Cell Transplantation

This study aimed to summarize the experience of precise nursing in 6 patients who experienced failed allogeneic hematopoietic stem cell transplantations (allo-HSCTs) that underwent second allo-HSCT salvage treatment. The key points of nursing care included strictly implementing infection prevention and control measures to prevent secondary infections, precise symptom management to improve the graft survival rate of patients, formulating reasonable nutrition programs to meet their requirements, and paying attention to the psychological care of patients to enhance their self-confidence in overcoming diseases. The patients developed different degrees of complications in the process of transplantation. During the transplantation, 2 patients had oral mucositis, 2 had hemorrhagic cystitis, 3 had a perianal infection, and one had lower gastrointestinal bleeding. After careful treatment and nursing, the neutrophils transplanted in the 6 patients were alive at a median of 16.5 (13-20) days after the second allo-HSCT, and the patients were successfully transferred out of the laminar flow chamber.

Evaluation of the Antimicrobial Effect on Enterococcus Faecalis of Bioceramic Cements with and without Silver Nanoparticles.

To compare the antimicrobial effect of bioceramic endodontic cements with and without silver nanoparticles on Enterococcus faecalis. Six groups were evaluated (n=8), and divided according to the materials: MTA Flow + AgNP ; MTA Flow Group; Bio C Repair + AgNP; Bio C Repair; PBS Cimmo + AgNP; PBS Cimmo. The groups were maintained for 72 h in the suspension of Enterococcus faecalis in Simulated Body Fluid (SBF). Samples of 100 μL were removed from the suspension at 0, 24, 48 and 72 h and seeded in triplicate in a Petri dish. Colony forming units (CFU) were counted using a colony counter. All procedures described were performed in a laminar flow chamber. Two-way ANOVA followed by Tukey's post hoc test and paired t-test were used for statistical analyses (α = 0.05). The addition of silver nanoparticles resulted in a statistically significant difference for MTA and CIMMO PBS cements (p⟨0.05), with the lowest bacterial growth being shown by the MTA group. For all groups, only the times of 48 and 72 h presented results without differences. The addition of silver nanoparticles to bioceramic cements was efficient to promote an acceleration of bacterial death.

In vitro germination and cryopreservation technique for long-term pollen conservation of underutilized legume: Grasspea (Lathyrus sativus)

Grasspea (Lathyrus sativus L.) is an underutilized pulse crop which can withstand adverse environmental conditions such as drought, heat, salinity, waterlogging, pest and diseases. To facilitate hybridization studies, pollen cryoconservation was attempted in L. sativus. Among the different media combination tested for in vitro pollen germination, BK medium with 15% sucrose was optimal. Pollen viability was tested at different storage regimes, viz. 25, 4, -20 and -196 ºC at different storage duration (1, 3, 5, 7, 9, 24 h, 1 week, 2 week and 6 months). For long-term pollen cryopreservation, an ideal MC of 14–16% was achieved by desiccating the pollen for 10 min in a laminar air flow (LAF) chamber. Negative correlation was found between pollen viability, storage duration and temperature (25, 4 and -20°C). Cryopreserved (-196°C) pollen showed significantly higher viability compared to all the other storage conditions. The standardized cryoconservation protocol was applied to 20 accessions of Lathyrus sativus for conservation up to six months without loss of pollen viability. Successful fertilization, fruit and seed set was observed in cross combinations attempted using cryoconserved pollen without any incompatibility barriers. Hence, the present protocol can be used for long-term cryoconservation of L. sativus pollen. The development of an effective long-term storage method of Lathyrus sativus pollen ensures the availability of pollen for grasspea breeding throughout the year.

Characterization of cultivable intestinal microbiota in Rhynchophorus palmarum Linnaeus (Coleoptera: Curculionidae) and determination of its cellulolytic activity.

Rhynchophorus palmarum Linnaeus is an agricultural pest that affects various palm crops, including coconut (Cocos nucifera) plantations which are prominent in the economy of Northeastern Brazil. Characterization of the intestinal microbiota of R. palmarum, as well as elucidation of aspects related to the biochemistry and physiology of the insect's digestion, isessential for intervention in specific metabolic processes as a form of pest control. Thus, this study aimed to characterize the intestinal microbiota of R. palmarum and investigate its ability to degrade cellulosic substrates, to explore new biological control measures. Intestinal dissection of eight adult R. palmarum insects was performed in a laminar flow chamber, and the intestines were homogenized in sterile phosphate-buffered saline solution. Subsequently, serial dilution aliquots of these solutions were spread on nutritive agar plates for the isolation of bacteria and fungi. The microorganisms were identified by matrix-assisted laser desorption/ionization with a time-of-flight mass spectrometry and evaluated for their ability to degrade cellulose. Fourteen bacterial genera (Acinetobacter, Alcaligenes, Arthrobacter, Bacillus, Citrobacter, Enterococcus, Kerstersia, Lactococcus, Micrococcus, Proteus, Providencia, Pseudomonas, Serratia, and Staphylococcus) and two fungal genera (Candida and Saccharomyces)-assigned to the Firmicutes, Actinobacteria, Proteobacteria, and Ascomycota phyla-were identified. The cellulolytic activity was exhibited by six bacterial and one fungal species; of these, Bacillus cereus demonstrated the highest enzyme synthesis (enzymatic index = 4.6). This is the first study characterizing the R. palmarum intestinal microbiota, opening new perspectives for the development of strategies for the biological control of this insect.

Ex Vivo Evaluation of Bacterial Leakage and Coronal Sealing Capacity of Six Materials in Endodontically Treated Teeth.

Successful endodontic treatment requires an effective coronal sealing to prevent the penetration of saliva and microorganisms into the root canal system. We aimed to investigate the sealing capacity of Maxxion R, Intermediate Restorative Material (IRM), Mineral Trioxide Aggregate-like material (Biodentine), White Cimpat, Flow Resin and Z250 Resin against Enterococcus (E.) faecalis infiltrates, when used as coronal sealants after endodontic treatment. Sixty-six roots of adult lower premolars were randomly divided into 6 experimental groups with 10 roots each (n=10), and two control groups (positive and negative) with three roots each. The root canals were instrumented to ProTaper F3 file, irrigated with 2.5% NaOCl and 17% EDTA, and filled using Tagger's Hybrid technique with AH-Plus cement. After removing 2 mm of the coronal third filling with a Gates Glidden #6 drill, the cervical portion of each of the sixty roots was sealed with a 2 mm-thick plug, plus the respective material being tested in this study. All roots were fitted to silicone devices (Eppendorf) with cut extremities and sterilized with ethylene oxide; experimental procedures were performed in a laminar flow chamber for aseptic chain maintenance. All specimens were inoculated with E. faecalis, and the culture medium was renewed every 3 days for 60 days. Medium turbidity was evaluated daily. The obtained data were subsequently submitted to analysis of variance (ANOVA-R) complemented by Student's t-test at a significance level of 5%. Analyzes of variance were calculated using the SAS system GLIMMIX procedure. Biodentine (56.90), Z250 Resin (54.90) and White Cimpat (53.30) resisted contamination for a longer time compared to Maxxion R (51.30), Flow Resin (50.70), and IRM (48.70) over a period of 60 days. Biodentine, Resin Z 250 and White Cimpat presented the lowest infiltration averages when compared to the other tested materials.

Reconstituted mRNA COVID-19 vaccines may maintain stability after continuous movement

ObjectivesThere is an urgent need to ameliorate the possibilities of transporting reconstituted mRNA vaccines from the centralized preparation centres to the vaccination sites to improve the efficiency of the vaccination campaign against coronavirus disease 2019 (COVID-19). We have analysed the integrity of the Pfizer–BioNTech and Moderna vaccines under different movement conditions to provide information that may improve the distribution of vaccines to the target population. MethodsSyringes of reconstituted Pfizer–BioNTech or Moderna COVID-19 vaccines were prepared in a laminar flow chamber to be subjected to a stability analysis in order to evaluate the impact of movement on mRNA integrity. RNA integrity was checked by the lack of RNA peaks under the original mRNA peak in the electropherogram resulting from potential fragments from RNA degradation. Samples were then exposed for 180 min at room temperature (21 ± 1°C, 55 ± 10% humidity) under different movement conditions. ResultsWe report that the integrity of the mRNA in the reconstituted COVID-19 vaccines after continuous moderate movement at room temperature is maintained for at least 3 hours, with values of fluorescence units (FU) under the original mRNA peak of 0.38 ± 0.06 in the Pfizer–BioNTech vaccine and 0.96 ± 1.18 FU in the Moderna vaccine, equal to the values obtained without movement (0.36 ± 0.08 FU in the Pfizer–BioNTech and 1.12 ± 0.19 FU in the Moderna). In contrast, the integrity of these vaccines exposed to repeated Vortex shaking was significantly impaired (p < 0.001) with values under the original mRNA peak of 1.34 ± 0.31 FU for the Pfizer–BioNTech and 5.03 ± 1.16 FU for the Moderna samples. ConclusionsThe stability of these reconstituted vaccines reported here may improve the efficiency of the ground transportation and distribution of the vaccines, which may lead to shorter and more homogeneous vaccinations in cities and rural areas.

CD8 Co-Receptor Enhances T-Cell Activation without Any Effect on Initial Attachment.

The scanning of surrounding tissues by T lymphocytes to detect cognate antigens requires high speed, sensitivity and specificity. T-cell receptor (TCR) co-receptors such as CD8 increase detection performance, but the exact mechanism remains incompletely understood. Here, we used a laminar flow chamber to measure at the single molecule level the kinetics of bond formation and rupture between TCR- transfected CD8+ and CD8− Jurkat cells and surfaces coated with five peptide-exposing major histocompatibility antigens (pMHCs) of varying activating power. We also used interference reflection microscopy to image the spreading of these cells dropped on pMHC-exposing surfaces. CD8 did not influence the TCR–pMHC interaction during the first few seconds following cell surface encounter, but it promoted the subsequent spreading responses, suggesting that CD8 was involved in early activation rather than binding. Further, the rate and extent of spreading, but not the lag between contact and spreading initiation, depended on the pMHC. Elucidating T-lymphocyte detection strategy may help unravel underlying signaling networks.

How Microbes Use Force To Control Adhesion.

Microbial adhesion and biofilm formation are usually studied using molecular and cellular biology assays, optical and electron microscopy, or laminar flow chamber experiments. Today, atomic force microscopy (AFM) represents a valuable addition to these approaches, enabling the measurement of forces involved in microbial adhesion at the single-molecule level. In this minireview, we discuss recent discoveries made applying state-of-the-art AFM techniques to microbial specimens in order to understand the strength and dynamics of adhesive interactions. These studies shed new light on the molecular mechanisms of adhesion and demonstrate an intimate relationship between force and function in microbial adhesins.

Standardization of surface sterilization protocol for &lt;em&gt;in vitro &lt;/em&gt;mass multiplication of grape rootstock dog ridge (&lt;em&gt;Vitis champini &lt;/em&gt;P.)

To standardize surface sterilization protocol in grape Dog Ridge rootstock, two types of explants viz., axillary buds and shoot tips were subjected to surface sterilization with sodium hypochlorite (0.25% and 0.5%) for three different duration (5,10 & 15 minutes). Prior to surface sterilization, the explants were pretreated with Carbendazim (0.3% and 0.5%) for 30 min. Pre-treatment of the axillary buds with 0.5% Carbendazim for 30 minutes and surface sterilization with 70% ethanol for 30 seconds followed by 0.5% sodium hypochlorite for 10 minutes under laminar air flow chamber resulted in the highest survival rate (68.33%) with least contamination (15.00%) and mortality (16.67%). However, in shoot tips, the highest survival rate (56.67%) with least contamination (30.00%) and mortality (13.33%) was recorded by pre-treating with 0.3% Carbendazim for 30 minutes and surface sterilization with 70% ethanol for 30 seconds followed by 0.25% sodium hypochlorite for 10 minutes.

Influence of Fibrinogen on Staphylococcus epidermidis Adhesion Can Be Reversed by Tuning Surface Nanotopography.

Surface modifications in the nanoscale regime have shown promising potential in the combat against bacterial adhesion and colonization of surfaces. However, detailed knowledge of how the bacteria-substrate interactions occur is still limited. Herein we have used a gradient in nanostructure density on a surface, realized by immobilizing 40 nm sized silicon dioxide nanoparticles with increasing distance on a glass surface, to systematically study the initial attachment of Staphylococcus epidermidis with or without the presence of human fibrinogen. By using a parallel plate laminar flow chamber, we found a near-linear positive correlation between the adhesion of S. epidermidis with increasing nanoparticle density on unmodified (hydrophilic) nanogradients as well as on gradients where polyethylene glycol was immobilized on the surface in-between nanoparticles. However, if the nanostructured gradient was precoated with human fibrinogen the opposite relationship was observed, although the adsorbed amount of fibrinogen was found to be higher on nanostructured than on smooth surfaces. Our results highlight that even minute changes of the nanotopography on a surface can have profound impact on initial attachment of S. epidermidis to biomaterial surfaces and that the presence of nanostructures strongly hampered the cell's ability to bind to adsorbed fibrinogen, possibly due to changes in the orientation or secondary structure of the fibrinogen molecule upon adsorption.

An Experimental Study of Homogeneous Nucleation of Supersaturated Antimony Vapor: Determination of the Surface Tension of a Critical Nucleus

Homogeneous nucleation of supersaturated antimony vapor has been studied in a laminar-flow chamber with the use of transmission electron microscopy, diffusion spectrometer of aerosols, supersaturation cutoff, laser light scattering, and other methods. Surface tension σs of a critical nucleus and radius Rs of its surface of tension have been determined from the experimentally measured temperature field by numerical simulation of the processes occurring in the chamber. The calculation results are in good agreement with the measured profile of a deposit on chamber walls, the average size and concentration of formed aggregates, the average size of primary particles, and their number in an aggregate. Equivalent volume Veq = 0.87 cm3 of the zone of intense nucleation, average nucleation rate I = 5 × 1010 cm−3 s−1, average supersaturation S4 = 3.2 × 106, average temperature T = 421 K in this zone, and radius Rs = 0.63 nm and surface tension σs = 220 mN/m of critical nuclei formed in this zone have been calculated. The surface tension of antimony nuclei has appeared to be lower than the surface tension of its planar surface by 46%. In our previous works, it was found that the surface tension of critical bismuth nuclei was, on the contrary, markedly higher than that of its planar surface. Different signs of the deviation from the surface tension of a planar surface have, for the first time, been observed for elements of the same group.

Nanobody-CD16 Catch Bond Reveals NK Cell Mechanosensitivity

Antibodies are key tools in biomedical research and medicine. Their binding properties are classically measured in solution and characterized by an affinity. However, in physiological conditions, antibodies can bridge an immune effector cell and an antigen-presenting cell, implying that mechanical forces may apply to the bonds. For example, in antibody-dependent cell cytotoxicity—a major mode of action of therapeutic monoclonal antibodies—the Fab domains bind the antigens on the target cell, whereas the Fc domain binds to the activating receptor CD16 (also known as FcgRIII) of an immune effector cell, in a quasi-bidimensional environment (2D). Therefore, there is a strong need to investigate antigen/antibody binding under force (2D) to better understand and predict antibody activity in vivo. We used two anti-CD16 nanobodies targeting two different epitopes and laminar flow chamber assay to measure the association and dissociation of single bonds formed between microsphere-bound CD16 antigens and surface-bound anti-CD16 nanobodies (or single-domain antibodies), simulating 2D encounters. The two nanobodies exhibit similar 2D association kinetics, characterized by a strong dependence on the molecular encounter duration. However, their 2D dissociation kinetics strongly differ as a function of applied force: one exhibits a slip bond behavior in which off rate increases with force, and the other exhibits a catch-bond behavior in which off rate decreases with force. This is the first time, to our knowledge, that catch-bond behavior was reported for antigen-antibody bond. Quantification of natural killer cells spreading on surfaces coated with the nanobodies provides a comparison between 2D and three-dimensional adhesion in a cellular context, supporting the hypothesis of natural killer cell mechanosensitivity. Our results may also have strong implications for the design of efficient bispecific antibodies for therapeutic applications.

ROR2 involvement in endothelial cells responses to flow

Endothelial cells (ECs) are sensitive to physical forces created by blood flow, especially to shear stress (SS). ECs transduce this mechanical forces into intracellular signals leading to gene expression, cytoskeleton reorganization, cell elongation and polarization against blood flow direction. Defects in ECs adaption to blood flow are highly correlated with cardiovascular diseases including atherosclerosis. Recently, it has been shown that non-canonical Wnt signaling modulates the endothelial shear stress flow sensor in vascular remodeling. ROR2, a receptor tyrosine kinase, is known to regulate non canonical Wnt/PCP signaling. This study investigates the role of ROR2 in ECs response to flow. Different types of ECs were exposed to low orbital shear stress (OSS) (3,6 dynes/cm 2 ). After 24 h or 72 h of OSS, ROR2 and Klf2, a flow-induced gene, expression were assessed by qRT-PCR and/or Western Blot. ROR2 gain- (lentivirus) and loss-of-function (siRNA) were used to decipher its role in ECs flow response. ECs polarization under laminar shear stress (LSS) were studied using laminar flow chamber slide. After 18 h of LSS (5 dynes/cm 2 ), ECs were immunostained for VE-cadherin, WGA, ROR2 and pericentrin. As expected, OSS induced Klf2 expression as compared to static condition. Interestingly, ROR2 expression was induced at the protein and gene level by OSS. To analyse whether ROR2 could be upstream or downstream Klf2 induction, ECs were treated with ROR2 or control siRNA and subjected to OSS for 24 h. siRNA depletion of ROR2 decreased flow-induced Klf2 expression. In LSS conditions, ECs was mostly polarized against flow direction (pericentrin, Hoechst localization) and we observed ROR2 relocalization at cell-cell junctions, as compared to static conditions. This study shows that ROR2 is involved in ECs responses to flow. Study of ROR2 signaling is under investigation to understand how ROR2 could regulate ECs properties.

Sealing Capacity of Bulk-fill Resin in Endodontically Treated Teeth

The objective of the study is to evaluate the cervicalapical sealing of bulk-fill flow resins associated with a universal adhesive system, in endodontically treated teeth, considering two methods of evaluation. The samples used in the bacterial leakage analysis were autoclaved, filled inside a laminar flow chamber, and divided into four experimental groups (n = 8) according to the restorative material: Filtek Bulk-fill flow; Surefil SDR flow; TetricEvoflow and the positive control. The samples were inoculated with the Enterococcus faecalis (E. faecalis), every 7 days and the microleakage was evaluated on a daily basis for 60 days. Microleakage tested with dye (n = 5) was considered in 2-time intervals of evaluation (24 hours and 72 hours), and the results were obtained in scores from 0-5. Data were submitted to the statistical tests, at a level of significance of 0.05. About 12.5% of the FBF specimens showed bacterial microleakage as from the thirteenth day, and SDR, from the 20th day. TEF presented the highest percentage of microleakage at 40 days, concluding the 60 days with 37.5% of viable specimens. The Log-rank test revealed that the survival curve of TEF was statistically significant in comparison with those of the other groups. In the test with dye TEF and SDR presented the highest and lowest rate of microleakage, respectively, with statistically significant differences in the time interval of 72h. The resins FBF, SDR, and TEF were incapable of promoting the hermetic sealing of fillings in the root canal system. No bulk-fill flux studied was able to completely eliminate microleakage, despite the best performance with respect to the microleakage time presented by Filtek Bulk fill, followed by Surefil SDR flow.

Removal of Very Small Submicrometric Particles by Water Nucleation: Effects of Chemical–Physical Properties of Particles

The control of particle emissions from industrial plants is a crucial point in pollution control mainly because the commonly used abatement devices are inefficient in the dimensional range between 0.1 and 1 μm. An innovative technique to control particle emissions exploits the water vapor condensation onto submicrometric particles acting as condensation nuclei. In this way, particle sizes increase from nanometric up to micrometric scale. The aim of this work is to analyze the 150 nm particle growth process, activated via a heterogeneous water condensation mechanism, as a function of the vapor concentration. Particle chemical–physical features are also taken into account. The evolution of the particle growth process has been followed at a lab scale along the axis of a laminar flow chamber by means of a spatially resolved measurement of the polarization ratio of the condensation nuclei and growing droplets. The main result reported here is the scheme of interpretation of the temporal profile of the polarization ratio related to the composite particle (particle embedded in the water layer) growth. The controlling mechanism of the overall condensation process has been identified with respect to the saturation conditions, evaluated on the basis of different theories available in the literature. The covering process has been found to be active also under conditions far from saturation of the vapor bulk phase. Moreover, it has been clearly shown that, irrespective of the particle nature, the nucleation activation and droplet growth occur almost simultaneously on all particles present in the control volume, with a capture efficiency close to unity. The water nucleation activation time also depends upon the particle chemical–physical characteristics. This paper also demonstrates that the experimentally determined characteristic times of nucleation and growth of the liquid layer are compatible with residence times of an industrial unity and can be used to condition its design.