Iron was shocked and probed at unprecedented time and strain rate to show all of its known structural types in 2.5 ns.
Iron is one of the most studied chemical elements due to its sociotechnological ...and planetary importance; hence, understanding its structural transition dynamics is of vital interest. By combining a short pulse optical laser and an ultrashort free electron laser pulse, we have observed the subnanosecond structural dynamics of iron from high-quality x-ray diffraction data measured at 50-ps intervals up to 2500 ps. We unequivocally identify a three-wave structure during the initial compression and a two-wave structure during the decaying shock, involving all of the known structural types of iron (α-, γ-, and ε-phase). In the final stage, negative lattice pressures are generated by the propagation of rarefaction waves, leading to the formation of expanded phases and the recovery of γ-phase. Our observations demonstrate the unique capability of measuring the atomistic evolution during the entire lattice compression and release processes at unprecedented time and strain rate.
The past decade has seen a rapid increase of numerical simulation studies on photobioreactors (PBRs). Developments in computational fluid dynamics (CFD) and the availability of more powerful ...computers have paved the way for the modeling and designing PRBs, a strategy that was abandoned from the late 1970s until the 1980s because of its complexity. This paper reviews the present status of numerical modeling for PBRs as well the application of CFD in the design of PBR for the mass production of microalgae. Emphasis is on the major breakthroughs in PBR design that may lead to scaling-up. Most simulations have been conducted in bubble column PBRs, which offer many advantages. Their geometry is simple in design with no moving parts, and they are easy to construct and operate. A majority of published simulation studies used two-phase models (air and water) and employed the Eulerian-Eulerian mixture model. CFD models have been vigorously validated by experimental and laboratory studies, with most claiming to have achieved good results. However, current PBR scale-up projects still need to resolve hydrodynamic issues within the PBR, in order to optimize factors for microalgal growth. To create ideal conditions inside the PBR, the main factors that influence microalgal growth such as light intensity and distribution, gas injection and mixing, and hydrodynamics/flow pattern which are the key for design and scale up must be thoroughly understood. The present practice of PBR design using CFD can be considered both an art and a science because of some numerical simulation issues which are yet to be resolved and the complexity of fluid mechanics inside the PBRs. Nonetheless, CFD has proven to be an effective tool in predicting the complex inherent phenomena in the PBRs. The CFD technique has shown to be very promising to successfully design and develop PBRs which can be commercially available for scale-up.
In a randomized, double-blind, prospective study, we have evaluated the effect of i.v. infusion of magnesium sulphate during spinal anaesthesia on postoperative analgesia and postoperative analgesic ...requirements.
Forty patients undergoing total hip replacement arthroplasty under spinal anaesthesia were included. After the induction of spinal anaesthesia, the magnesium group (Group M) received magnesium sulphate 50 mg kg−1 for 15 min and then 15 mg kg−1 h−1 by continuous i.v. infusion until the end of surgery. The saline group (Group S) received the same volume of isotonic saline over the same period. After surgery, a patient-controlled analgesia (PCA) device containing morphine and ketorolac was provided for the patients. Postoperative pain scores, PCA consumption, and the incidences of shivering, postoperative nausea, and vomiting were evaluated immediately after surgery, and at 30 min, 4, 24, and 48 h after surgery. Serum magnesium concentrations were checked before the induction of anaesthesia, immediately after surgery, and at 1 and 24 h after surgery.
Postoperative pain scores were significantly lower in Group M at 4, 24, and 48 h after surgery (P<0.05). Cumulative postoperative PCA consumptions were also significantly lower in Group M at 4, 24, and 48 h after surgery (P<0.05). Postoperative magnesium concentrations were higher in Group M (P<0.05 at 4, 24, and 48 h after surgery), but no side-effects associated with hypermagnesemia were observed. Haemodynamic variables and the incidences of shivering, nausea, and vomiting were similar in the two groups.
I.V. magnesium sulphate administration during spinal anaesthesia improves postoperative analgesia.
The aim of this study was to evaluate the polymerization behavior and depth of cure (DOC) of recently introduced resin composites for posterior use: highly filled flowable composite and composites ...for bulk fill. A highly filled flowable (G-aenial Universal Flo GUF), two bulk-fill flowables (Surefil SDR Flow SDR and Venus Bulk fill VBF), and a bulk-fill nonflowable composite (Tetric N-Ceram Bulk fill TBF) were compared with two conventional composites (Tetric Flow TF, Filtek Supreme Ultra FS). Linear polymerization shrinkage and polymerization shrinkage stress were each measured with custom-made devices. To evaluate DOC, the composite specimen was prepared using a mold with a hole of 4 mm depth and 4 mm internal diameter. The hole was bulk filled with each of the six composites and light cured for 20 seconds, followed by 24 hours of water storage. The surface hardness was measured on the top and the bottom using a Vickers microhardness (HV) indenter. The linear polymerization shrinkage of the composite specimens after photo-initiation decreased in the following order: TF and GUF > VBF > SDR > FS and TBF (p<0.05). The polymerization shrinkage stress of the six composite groups decreased in the following order: GUF > TF and VBF > SDR > FS and TBF (p<0.05). The mean bottom surface HV of SDR and VBF exceeded 80% of the top surface HV (HV-80%). However, the bottom of GUF and TBF failed to reach HV-80%. A highly filled flowable (GUF) revealed limitations in polymerization shrinkage and DOC. Bulk-fill flowables (SDR and VBF) were properly cured in 4-mm bulk, but they shrank more than the conventional nonflowable composite. A bulk-fill nonflowable (TBF) showed comparable shrinkage to the conventional nonflowable composite, but it was not sufficiently cured in the 4-mm bulk.
Adding a small amount of Al to the well-known high entropy alloy (HEA), Al0.1CoCrFeNi, to form Al0.3CoCrFeNi, leads to the precipitation of highly refined ordered L12 precipitates, which are stable ...at 550°C. However, the L12 precipitates (stoichiometry of (Ni,Cr)3(Al,Fe,Co)) are de-stabilized and replaced by coarser B2 precipitates on annealing at 700°C. Contrastingly, in the Co-free, Al0.3CuCrFeNi2 high entropy alloy, the L12 precipitates are stable at both 550°C (~5nm) and 700°C (~50nm), and exhibit a stoichiometry of (Ni,Cu)3(Al,Fe,Cr). These results lead to interesting insights into the stability of ordered phases in HEAs as a function of composition and temperature.
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Plasmonic alloy has attracted much interest in tailoring localized surface plasmon resonance (LSPR) for recent biosensing techniques. In particular, paper-based plasmonic substrates allow ...capillary-driven lateral flow as well as three-dimensional metal nanostructures, and therefore they become actively transferred to LSPR-based biosensing such as surface-enhanced Raman spectroscopy (SERS) or metal-enhanced fluorescence (MEF). However, employing plasmonic alloy nanoislands on heat-sensitive substrate is still challenging, which significantly inhibits broad-range tailoring of the plasmon resonance wavelength (PRW) for superior sensitivity. Here we report paper-based plasmonic substrate with plasmonic alloy of Au/Ag nanocomposites for highly sensitive MEF and SERS biosensing applications. The nanofabrication procedures include concurrent deposition of Au and Ag below 100 °C without any damage on cellulose fibers. The Au/Ag nanocomposites feature nanoplasmonic alloy with single plasmon peak as well as broad-range tunability of PRW by composition control. This paper-based plasmonic alloy substrate enables about twofold enhancement of fluorescence signals and selective MEF after paper chromatography. The experimental results clearly demonstrate extraordinary enhancement in SERS signals for picomolar detection of folic acid as a cancer biomarker. This new method provides huge opportunities for fabricating plasmonic alloy on heat-sensitive substrate and biosensing applications.
Aim
To assess the biological effects, including odontoblastic differentiation of a novel light‐curable material (TheraCal), on human dental pulp cells (hDPCs).
Methodology
The hDPCs were isolated ...from freshly extracted, caries‐free third molars. Ten discs of TheraCal and MTA (8 mm in diameter and 3 mm in height) were incubated in α‐minimum essential medium (α‐MEM) and the supernatant collected. Viability of hDPCs in response to TheraCal and MTA was measured using the WST‐1 assay. RT‐PCR and real‐time PCR were used to detect the gene expression of dentine sialophosphoprotein (DSPP) and dentine matrix protein‐1 (DMP‐1). ALP staining and Alizarin red S staining were used to evaluate the expression of alkaline phosphatase (ALP) and mineralization behaviour. One‐way analysis of variance and Tukey's post hoc test were used to determine the statistically significant differences as a result of the variation in test materials (P < 0.05).
Results
The effects of TheraCal and MTA on cell viability were similar except at the highest concentration. The mRNA level of DSPP increased significantly in the MTA group relative to the control at day 1 and 3 (P < 0.05). Also, the mRNA level of DSPP increased significantly in the TheraCal group relative to the control at day 3 (P < 0.05). The increased mRNA level of DMP‐1 was 2.5‐fold and 2.3‐fold each in the MTA and TheraCal groups relative to the control (P < 0.05). Cells exposed to MTA exhibited a 1.4‐fold increase of ALP staining relative to control (P < 0.05). In the mineralization assay, increased calcium nodule formation was twofold and 1.3‐fold each in the MTA and TheraCal groups compared to the control (P < 0.05).
Conclusions
TheraCal and MTA had the ability to induce odontoblastic differentiation and mineralization of hDPCs.
Using data from the MMS mission and the First‐Order Taylor Expansion (FOTE) method, here we reveal electron distribution functions around a reconnection X‐line at the Earth's magnetopause. We find ...cigar distribution of electrons in both the magnetosphere‐side and magnetosheath‐side inflow regions, isotropic distribution of electrons at the separatrix, and loss of high‐energy electrons in the antiparallel direction in the magnetosheath‐side inflow region. We interpret the formation of cigar distribution in the inflow regions using the Fermi mechanism—as suggested in previous simulations, the loss of high‐energy electrons in the magnetosheath side using the parallel electric fields—which evacuate electrons to escape the diffusion region along the antiparallel direction, and the isotropic distribution at the separatrix using the pitch angle scattering by whistler waves—which exist frequently at the separatrix. We also find that the electron distribution functions can change rapidly (within 60 ms) from isotropic to cigar as the spacecraft moves slightly away from the separatrix.
Plain Language Summary
Magnetic reconnection is a key process responsible for many explosive phenomena in nature such as solar flares and magnetospheric substorms. Up to now, the electron behaviors (particularly electron distribution functions) around the reconnection X‐line have not been well revealed, because the X‐line topology is unavailable in previous study. Using data from the MMS mission and the newly developed FOTE method, here we investigate electron distribution functions around a reconnection X‐line and explain the formation mechanisms of these distributions successfully.
Key Points
For the first time, we reveal electron distributions around a reconnection X‐line using the FOTE method, rather than cartoons or simulations
We find different types of electron distributions around the X‐line, and explain the formation mechanisms of these distributions successfully
We find a rapid change of electron distribution within 60 ms. Such rapid change can only be revealed by FOTE but not other methods
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