Aim
To assess a novel, noninvasive intervention capable of mobilizing charged antibacterial nanoparticles to the apical portions of the root canal system, utilizing the principles of electrokinetics.
...Methods
Experiments were conducted in three stages. Stage‐1: A computer model was generated to predict and visualize the electric field and current density distribution generated by the proposed intervention. Stage‐2: Transport of chitosan nanoparticles (CSnp) was evaluated qualitatively using a transparent microfluidic model with fluorescent‐labelled CSnp. Stage‐3: An ex vivo model was utilized to study the antimicrobial efficacy of the proposed treatment against 3‐week‐old monospecies E. faecalis biofilms. Scanning electron microscopy (SEM) was also utilized in this stage to confirm the deposition of CSnp.
Results
The results of the computer simulations predicted an electric field and current density that reach their maxima at the apical constriction of the root canal. Correspondingly, the microfluidic experiments demonstrated rapid, controlled CSnp transport throughout the simulated root canal anatomy with subsequent distribution and deposition in the apical constriction as well as periapical regions. Infected root canals when subjected to the novel treatment method resulted in a mean bacterial reduction of 2.1 log CFU. SEM analysis revealed electrophoretic deposition of chitosan nanoparticles onto the root canal dentine walls in the apical region.
Conclusion
The findings from this study demonstrate that the combination of cationic antibacterial nanoparticles with a low‐intensity electric field results in particle transportation (electrophoresis) and deposition within the root canal. This results in a synergistic antibiofilm efficacy and has the potential to enhance root canal disinfection.
To evaluate the performance of a new catheter design based on different hydrodynamics aiming to reduce the development of biofilm, and compare it with a conventional Foley catheter (FC).
The new ...proposed design (NPD) catheter is a modification of the FC, based on asymmetric positioning of the balloon and additional drainage holes allowing continuous urine drainage and complete voiding of the bladder. A first experiment was undertaken to assess drainage capability, and a second experiment was performed using a bioreactor with a set-up simulating the bladder and using the test catheter as a flow-through system. The biofilm formation of five bacterial species associated with catheter-associated urinary tract infection (CAUTI) was determined after 24 h of incubation using an MTT assay. Morphological evaluation was performed using scanning electron microscopy. In-vitro determination of residual fluid, and quantitative and morphological data on biofilm formation on the intravesical and intraluminal parts of the tested catheters were assessed.
Residual fluid was significantly higher in the FC (5.60 ± 0.43 mL) compared with the NPD catheter (0.2 ± 0.03 mL). The NPD catheter showed significantly less biofilm formation (P<0.0001) than the FC. Catheter design had a variable effect on biofilm formation depending on the bacterial strain tested. There was significantly less intraluminal biomass compared with intravesical biomass in both catheters (P<0.0001). Multi-layered biofilms that covered the FC surfaces completely were seen for all tested strains, while the NPD catheter surfaces showed reduced biofilm formation.
Modifications of the hydrodynamic characteristics of a catheter can significantly reduce bacterial colonization. Integrated design approaches combining chemical, mechanical and topographical elements can help to reduce the occurrence of CAUTI.
Steep-slope transistors allow to scale down the supply voltage and the energy per computed bit of information as compared to conventional field-effect transistors (FETs), due to their sub-60 ...mV/decade subthreshold swing at room temperature. Currently pursued approaches to achieve such a subthermionic subthreshold swing consist in alternative carrier injection mechanisms, like quantum mechanical band-to-band tunneling (BTBT) in Tunnel FETs or abrupt phase-change in metal-insulator transition (MIT) devices. The strengths of the BTBT and MIT have been combined in a hybrid device architecture called phase-change tunnel FET (PC-TFET), in which the abrupt MIT in vanadium dioxide (VO
) lowers the subthreshold swing of strained-silicon nanowire TFETs. In this work, we demonstrate that the principle underlying the low swing in the PC-TFET relates to a sub-unity body factor achieved by an internal differential gate voltage amplification. We study the effect of temperature on the switching ratio and the swing of the PC-TFET, reporting values as low as 4.0 mV/decade at 25 °C, 7.8 mV/decade at 45 °C. We discuss how the unique characteristics of the PC-TFET open new perspectives, beyond FETs and other steep-slope transistors, for low power electronics, analog circuits and neuromorphic computing.
Release of bud dormancy in perennial woody plants is a temperature-dependent process and thus flowering in these species is heavily affected by climate change. The lack of cold winters in temperate ...growing regions often results in reduced flowering and low fruit yields. This is likely to decrease the availability of fruits and nuts of the
spp. in the near future. In order to maintain high yields, it is crucial to gain detailed knowledge on the molecular mechanisms controlling the release of bud dormancy. Here, we studied these mechanisms using sweet cherry (
L.), a crop where the agrochemical hydrogen cyanamide (HC) is routinely used to compensate for the lack of cold winter temperatures and to induce flower opening. In this work, dormant flower buds were sprayed with hydrogen cyanamide followed by deep RNA sequencing, identifying three main expression patterns in response to HC. These transcript level results were validated by quantitative real time polymerase chain reaction and supported further by phytohormone profiling (ABA, SA, IAA, CK, ethylene, JA). Using these approaches, we identified the most up-regulated pathways: the cytokinin pathway, as well as the jasmonate and the hydrogen cyanide pathway. Our results strongly suggest an inductive effect of these metabolites in bud dormancy release and provide a stepping stone for the characterization of key genes in bud dormancy release.
In this review we discuss conventional methods of performing biological assays and molecular identification and highlight their advantages and limitations. An alternative approach based on magnetic ...nanotechnology is then presented. Firstly, magnetic carriers are introduced and their biocompatibility and functionalisation discussed, with spotlights on functionalisation via self assembled monolayers and on methods of reducing nonspecific binding. In addition an introduction is provided to the basic physical concepts behind the various types of sensors used to detect magnetic labels. Finally, progress in the field of magnetic biosensors and the outlook for the future are discussed.
We consider the Schrödinger map initial-value problem $\cases \partial _{t}\phi =\phi \times \Delta \phi \,\text{on}\,{\Bbb R}^{d}\times {\Bbb R}, & \\ \phi (0)=\phi _{0}, &\endcases $ where ϕ: ℝ d × ...ℝ → 𝕊 2 ↪ ℝ 3 is a smooth function. In all dimensions d ≥ 2, we prove that the Schrödinger map initial-value problem admits a unique global smooth solution ϕ ∈ C(ℝ: $H_{Q}^{\infty}$ ), Q ∈ 𝕊 2 , provided that the data ϕ0 ∈ $H_{Q}^{\infty}$ is smooth and satisfies the smallness condition ∥ϕ0−Q∥ Ḣd/2 ⪡ 1. We prove also that the solution operator extends continuously to the space of data in Ḣ d/2 ∩ $\dot{H}_{Q}^{d/2-1}$ with small Ḣ d/2 norm.
Abstract
We have investigated the pinning potential of high-quality single crystals of superconducting material CaKFe
4
As
4
having high critical current density and very high upper critical field ...using both magnetization relaxation measurements and frequency-dependent AC susceptibility. Preliminary studies of the superconducting transition and of the isothermal magnetization loops confirmed the high quality of the samples, while temperature dependence of the AC susceptibility in high magnetic fields show absolutely no dependence on the cooling conditions, hence, no magnetic history. From magnetization relaxation measurements were extracted the values of the normalized pinning potential
U
*, which reveals a clear crossover between elastic creep and plastic creep. The extremely high values of
U
*, up to 1200 K around the temperature of 20 K lead to a nearly zero value of the probability of thermally-activated flux jumps at temperatures of interest for high-field applications. The values of the creep exponents in the two creep regimes resulted from the analysis of the magnetization relaxation data are in complete agreement with theoretical models. Pinning potentials were also estimated, near the critical temperature, from AC susceptibility measurements, their values being close to those resulted (at the same temperature and DC field) from the magnetization relaxation data.
Duvalo “volcano” is a site of anomalous geogenic degassing close to Ohrid (North Macedonia) not related to volcanic activity, despite its name. CO2 flux measurements made with the accumulation ...chamber (321 sites over ∼50,000 m2) showed fluxes up to nearly 60,000 g m−2 d−1, sustaining a total output of ∼67 t d−1. Soil gas samples were taken at 50 cm depth from sites with high CO2 fluxes and analyzed for their chemical and isotope composition. The gas is mainly composed by CO2 (>90%) with significant concentrations of H2S (up to 0.55%) and CH4 (up to 0.32%). The isotope compositions of He (R/RA 0.10) and of CO2 (δ13C ∼ 0‰) exclude significant mantle contribution, while δ13C‐CH4 (∼−35‰) and δ2H‐CH4 (∼−170‰) suggest a thermogenic origin for CH4. The area is characterized by intense seismic activity and Duvalo corresponds to an active tectonic structure bordering the Ohrid graben. The production of H2S within the stratigraphic sequence may be explained by thermochemical reduction of sulfate. The uprising H2S is partially oxidized to sulfuric acid that, reacting with carbonate rocks, releases CO2. The tectonic structure of the area favors fluid circulation, sustaining H2S production and oxidation, CO2 production and allowing the escape of the gases to the atmosphere. In the end, Duvalo represents a tectonic‐related CO2 degassing area whose gases originate mostly, if not exclusively, in the shallowest part of the crust (<10 km). This finding highlights that even systems with trivial mantle contribution may sustain intense CO2 degassing (>1,000 t km−2 d−1).
Plain Language Summary
The carbon cycle is an important piece of the puzzle of the present climate change. While anthropogenic sources of atmospheric carbon are reasonably constrained, geological sources are much less. Among the latter, carbon release to the atmosphere in seismically active areas, though known from decades, is less studied. Here we estimate the total emission of carbon dioxide from Duvalo, an area near Ohrid (North Macedonia). The obtained value (67 metric tons per day) is comparable with some active volcanic areas in the region. Although local inhabitants call this area Duvalo volcano, no recent volcanic activity is recognized here. The composition of the gas released by this system seems also to rule out geothermal activity or deep contributions from the Earth's mantle. This study shows that natural degassing systems with relatively shallow crustal sources (few kilometers), may sustain intense gas emissions from the soil.
Key Points
The total CO2 output from Duvalo “volcano” has been estimated for the first time
Gas compositions rule out significant mantle contributions or recent volcanic activity while geothermal activity is improbable
An active fault system favors indirect gas production and upflow to the Earth's surface
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