Incorporation of cobalt ions into magnetoelectric gallium ferrite epitaxial films: tuning of conductivity and magnetization

Doping Ga0.6Fe1.4O3 thin films with magnetic Co²⁺ ions leads to a strong reduction in the charge conduction and does not lead to any modification of the ferrimagnetic transition. This is absolutely comparable to that observed with Mg-doping.

Factors affecting the success rate of buccal infiltration anaesthesia in the mandibular molar region

AIM

To compare the anaesthetic efficacy of mandibular second premolar infiltration (SP) with that of mandibular first molar infiltration (FM) in inducing pulpal anaesthesia in the mandibular first molar. To further investigate the mechanisms of action that underlie mandibular infiltration, gender-related differences in the anaesthetic efficacy were also assessed.

METHODOLOGY

A total of 29 adult subjects randomly received two sets of SP and FM injections using one cartridge (1.7 mL) of 4% articaine and 1 : 100 000 adrenaline at two separate appointments. The responses of the teeth were assessed using an electronic pulp tester over a 30-min period. A comparison of the anaesthetic success between the SP and FM infiltration routes was analysed using the McNemar's test. Gender-related differences in the anaesthetic success of infiltration routes were assessed using the Fisher's exact test.

RESULTS

For the second premolar and the first and second molar teeth, the success rates of SP were 72.4%, 62.1% and 48.3%, whereas the success rates of FM were 75.9%, 51.7% and 55.1%, respectively. There were no significant differences between the success rates of SP and FM or between the rates obtained for each tooth. Significant gender-related differences were observed for the second premolar (P < 0.01) and the first molar (P < 0.05) using FM. However, a significant difference was observed only for the second premolar using SP (P < 0.05).

CONCLUSIONS

The differences in the injection sites did not affect the anaesthetic success rates for the mandibular second premolar and molar teeth. However, articaine buccal infiltration produced a higher anaesthetic success rate in the second premolar and first molar teeth of Korean female patients.

Spectrum of the cavity-QED microlaser: strong coupling effects in the frequency pulling at off resonance

We report the first experimental observation of the cavity-QED microlaser spectrum, specifically the unconventional frequency pulling brought by a strong atom-cavity coupling at off resonance. The pulling is enhanced quadratically by the atom-cavity coupling to result in a sensitive response to the number of pumping atoms (2.1 kHz per atom maximally). Periodic variation of the pulling due to the coherent Rabi oscillation is also observed as the number of pumping atoms is increased across multiple thresholds.

Hypoxia-inducible factor-2α regulates Fas-mediated chondrocyte apoptosis during osteoarthritic cartilage destruction

Apoptosis of articular chondrocytes is associated with the pathogenesis of osteoarthritis (OA). Recently, we demonstrated that hypoxia-inducible factor (HIF)-2α, encoded by Epas1, causes OA cartilage destruction by regulating the expression of various matrix-degrading enzymes. Here, we investigated the involvement of HIF-2α in chondrocyte apoptosis and OA cartilage destruction. HIF-2α levels in human and mouse OA chondrocytes were markedly elevated in association with increased apoptosis of articular chondrocytes. Overexpression or knockdown of HIF-2α alone did not cause chondrocyte apoptosis. However, HIF-2α expression markedly increased chondrocyte apoptosis in the presence of an agonistic anti-Fas (CD95) antibody. HIF-2α enhanced Fas expression and potentiated downstream signaling pathways, increasing the activity of initiator and executioner caspases. Overexpression of HIF-2α in mouse cartilage tissue, either by intra-articular injection of Epas1 adenovirus (Ad-Epas1) or in the context of chondrocyte-specific Epas1 transgenic mice, increased chondrocyte apoptosis and cartilage destruction. In contrast, chondrocyte-specific knockout of Epas1 in mice suppressed DMM (destabilization of the medial meniscus)-induced chondrocyte apoptosis and inhibited OA cartilage destruction. Moreover, Fas-deficient mice exhibited diminished chondrocyte apoptosis and OA cartilage destruction in response to Ad-Epas1 injection or DMM surgery. Taken together, our results demonstrate that HIF-2α potentiates Fas-mediated chondrocyte apoptosis, which is associated with OA cartilage destruction.

Mapping Residual-Stress Distributions in a Laser-Peened Vit-105 Bulk-Metallic Glass Using the Focused-Ion-Beam Micro-Slitting Method

Measuring residual-stresses at the micron scale in glassy materials imposes experimental challenges, particularly when using diffraction, or other conventional laboratory methods, e.g., optical non-contact methods, grid methods, etc. In this short paper, a technique for mapping residual-stress profiles in amorphous materials with high spatial definition is used to measure residual-stresses in a laser-peened and fatigued bulk-metallic glass - Vit-105. The method involves local deposition of nano Pt dots patterns on the mapped region of the specimen and milling of a series of micro-slots of size 15 × 2 × 0.4 μm3 using the focused ion beam of a dual beam Field Emission Gun Scanning Electron Microscope / Focused Ion Gun (FEGSEM/FIB) instrument. The deformation fields in the vicinity of slots are reconstructed by the digital image correlation analyses (DICA) of FEGSEM images recorded during milling. The residual-stresses are inferred by fitting a reference displacement field obtained from finite-element analyses (FEA) with the recorded displacement field. In this way, residual-stress distributions have been characterized as a function of the distance from the laser-peened surface to a depth of 1,200 microns with a spatial resolution of 30 μm. The influence of fatigue loading on the compressive residual-stresses spatial distribution is studied and discussed. It was found that the fatigue loading significantly changes the compressive residual-stress spatial distribution in the laser-peened layer.