Misorientation-Angle-Dependent Phase Transformation in van der Waals Multilayers via Electron-Beam Irradiation

Misorientation-angle dependence on layer thickness is an intriguing feature of van der Waals materials, which causes stark optical gain and electrical transport modulation. However, the influence of misorientation angle on phase transformation is not determined yet. Herein, this phenomenon in a MoS₂ multilayer via in situ electron-beam irradiation is reported. An AA'-stacked MoS₂ bilayer undergoes structural transformation from the 2H semiconducting phase to the 1T' metallic phase, similar to a MoS₂ monolayer, which is confirmed via in situ transmission electron microscopy. Moreover, non-AA' stacking, which has no local AA' stacking order in the Moiré pattern, does not reveal such a phase transformation. While a collective sliding motion of chalcogen atoms easily occurs during the transformation in AA' stacking, in non-AA' stacking it is suppressed by the weak van der Waals strength and by the chalcogen atoms interlocked at different orientations, which disfavor their kinetics by the increased entropy of mixing.

Influence of Glass Microsphere Filler on the Rheological Behavior of an Epoxy Resin

The rheological behavior of epoxy resin filled with glass hollow microspheres was studied using three types of microspheres with different particle size distributions. The shear-rate dependence on viscosity, as well as relative apparent viscosity, of the suspensions was investigated at different microsphere filler loadings. The change in relative viscosity with different types of microsphere loads was also investigated using the established semi empirical model to estimate the critical filler load. It was found that the critical filler load for all suspensions tested depends mostly on the filler size distribution, neither on the average filler size nor on the specific surface area of the filler.

Influence of human parathyroid hormone during orthodontic tooth movement and relapse in the osteoporotic rat model: A preliminary study

OBJECTIVE

To investigate the effects of parathyroid hormone (PTH) on tooth movement in ovariectomized (OVX) rats by comparing the tooth movement distance and relapse and by examining the alveolar bone microstructure.

MATERIALS AND METHODS

Thirty 8-week-old female rats were classified into 3 groups: sham-operated, OVX and ovariectomized rats injected with PTH (PTH). Eight weeks later, a closed-coil spring appliance was placed between the maxillary incisor and the first molar and then activated with 50 cN of force. During tooth movement, 30 μg/kg of PTH was administered 3 times per week in the PTH group. Tooth movement distances were measured weekly. Five rats in each group were killed after 3 weeks for microcomputerized tomographic analysis, and the remaining 5 rats in each group were killed at an additional 3 weeks after the removal of the appliance to measure relapsed distance.

RESULTS

The OVX group showed significantly greater tooth movement compared to those in the other 2 groups at 2 and 3 weeks (P < .05). The relapse distance and relapse percentage for the OVX group were higher; however, it did not differ significantly from the PTH group. On micro-CT analysis, bone volume/tissue volume ratio and bone mineral density in the PTH group were significantly greater than in the OVX group (P < .05).

CONCLUSIONS

Application of PTH did not promote tooth movement in OVX rat, however, did lead to decrease in relapse tendency. Therefore, the application of PTH during orthodontic treatment of patients with osteoporosis should be carefully considered.

Obstetric and gynecologic ultrasound curriculum and competency assessment in residency training programs: consensus report

Ultrasound imaging has become integral to the practice of obstetrics and gynecology. With increasing educational demands and limited hours in residency programs, dedicated time for training and achieving competency in ultrasound has diminished substantially. The American Institute of Ultrasound in Medicine assembled a multi-Society Task Force to develop a consensus-based, standardized curriculum and competency assessment tools for obstetric and gynecologic ultrasound training in residency programs. The curriculum and competency-assessment tools were developed based on existing national and international guidelines for the performance of obstetric and gynecologic ultrasound examinations and thus are intended to represent the minimum requirement for such training. By expert consensus, the curriculum was developed for each year of training, criteria for each competency assessment image were generated, the pass score was established at or close to 75% for each, and obtaining a set of five ultrasound images with pass score in each was deemed necessary for attaining each competency. Given the current lack of substantial data on competency assessment in ultrasound training, the Task Force expects that the criteria set forth in this document will evolve with time. The Task Force also encourages use of ultrasound simulation in residency training and expects that simulation will play a significant part in the curriculum and the competency-assessment process. Incorporating this training curriculum and the competency-assessment tools may promote consistency in training and competency assessment, thus enhancing the performance and diagnostic accuracy of ultrasound examination in obstetrics and gynecology. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Biomechanical Parameters in Plantar Fasciitis Measured by Gait Analysis System With Pressure Sensor

Objective

To investigate the differences in biomechanical parameters measured by gait analysis systems between healthy subjects and subjects with plantar fasciitis (PF), and to compare biomechanical parameters between ‘normal, barefooted’ gait and arch building gait in the participants.

Methods

The researchers evaluated 15 subjects (30 feet) with bilateral foot pain and 15 subjects (15 feet) with unilateral foot pain who had a clinical diagnosis of PF. Additionally, 17 subjects (34 feet) who had no heel pain were recruited. Subjects were excluded if they had a traumatic event, prior surgery or fractures of the lower limbs, a leg length discrepancy of 1 cm or greater, a body mass index greater than 35 kg/m², or had musculoskeletal disorders. The participants were asked to walk with an arch building gait on a treadmill at 2.3 km/hr for 5 minutes. Various gait parameters were measured.

Results

With the arch building gait, the PF group proved that gait line length and single support line were significantly decreased, and lateral symmetry of the PF group was increased compared to that of the control group. The subjects with bilateral PF displayed significantly increased maximum pressure over the heel and the forefoot during arch building gait. In addition, the subjects with unilateral PF showed significantly increased maximum pressure over the forefoot with arch building gait.

Conclusion

The researchers show that various biomechanical differences exist between healthy subjects and those with PF. Employing an arch building gait in patients with PF could be helpful in changing gait patterns to normal biomechanics.

Comparative profiles of BRAF inhibitors: the paradox index as a predictor of clinical toxicity

BRAF inhibitor (BRAFi) therapy is associated with the induction of neoplasia, most commonly cutaneous squamous cell carcinoma (cuSCC). This toxicity is explained in part by “paradoxical ERK activation,” or the hyperactivation of ERK signaling by BRAFi in BRAF wild-type cells. However, the rate of cuSCC induction varies widely among BRAFi. To explore this mechanistically, we profiled paradoxical ERK activation by vemurafenib, dabrafenib, encorafenib (LGX818), and PLX8394, demonstrating that vemurafenib induces ERK activation the greatest, while dabrafenib and encorafenib have higher “paradox indices”, defined as the pERK activation EC₈₀ divided by the IC₈₀ against A375, corresponding to wider therapeutic windows for achieving tumor inhibition without paradoxical ERK activation. Our results identify differences in the paradox indices of these compounds as a potential mechanism for the differences in cuSCC induction rates and highlight the utility of using ERK activity as a biomarker for maximizing the clinical utility of BRAFi.

Room-Temperature H₂ Gas Sensing Characterization of Graphene-Doped Porous Silicon via a Facile Solution Dropping Method

In this study, a graphene-doped porous silicon (G-doped/p-Si) substrate for low ppm H₂ gas detection by an inexpensive synthesis route was proposed as a potential noble graphene-based gas sensor material, and to understand the sensing mechanism. The G-doped/p-Si gas sensor was synthesized by a simple capillary force-assisted solution dropping method on p-Si substrates, whose porosity was generated through an electrochemical etching process. G-doped/p-Si was fabricated with various graphene concentrations and exploited as a H₂ sensor that was operated at room temperature. The sensing mechanism of the sensor with/without graphene decoration on p-Si was proposed to elucidate the synergetic gas sensing effect that is generated from the interface between the graphene and p-type silicon.

Reductive dechlorination of trichloroethylene by polyvinylpyrrolidone stabilized nanoscale zerovalent iron particles with Ni

We developed a novel stabilized nanoscale zerovalent iron (NZVI) particles with Ni using an electron conducting polymer, polyvinylpyrrolidone (PVP), to selectively dechlorinate trichloroethylene (TCE) to non-toxic intermediates. The size of the PVP stabilized NZVI-Ni ((PVP-NZVI-Ni), average diameter: ∼20nm) is smaller than that of bare NZVI (50-80nm) due to the prevention of agglomeration of the resultant iron particles by PVP. PVP-NZVI-Ni showed a complete removal of TCE in 1h with superior dechlorination kinetics (k_obs=5.702h^-1) and ethane selectivity (98%), while NZVI-Ni showed 5 times slower dechlorination kinetics (1.218h^-1). Other PVP-NZVI-metals (i.e., Cu, Sn, Co, and Mn) also enhanced the TCE dechlorination, but they were much slower (k_obs=0.024-0.411h^-1) than that of PVP-NZVI-Ni. In column test, PVP-NZVI-Ni exhibited better mobility (95% of PVP-NZVI-Ni recovery in the eluent) than NZVI-Ni (1%). In addition, PVP-NZVI-Ni reductively transform TCE to ethane even under 10 cycles of repeated TCE dechlorination treatment.

Self-Generation of Reactive Oxygen Species on Crystalline AgBiO3 for the Oxidative Remediation of Organic Pollutants

In this study, we synthesized a novel perovskite nanomaterial consisting of AgBiO₃ nanoparticles (NPs) via an ion-exchange method for remediation of polluted environments. The AgBiO₃ NPs could self-produce significant amounts of reactive oxygen species (ROS) without light illumination or any other additional oxidant due to the controllable release of lattice oxygen from the crystalline AgBiO₃, resulting in the formation of ROS somehow. The self-produced ¹O₂, O₂^•-, and ^•OH were confirmed by electron spin resonance spectroscopy using a spin trap technique. We found that the AgBiO₃ NPs could be reused for the mineraliztion of most recalcitrant organic compounds alone, including Rhodamine B (RhB), phenol, 4-chlorophenol, 2,4-dichlorophenol, and bisphenol A. After the repeated eight cycles of continious treatment of RhB, AgBiO₃ NPs still achieved 79% of degradation after 30 min of treatment. Characterization results revealved that the lattice oxygen inside AgBiO₃ was activated to form active oxygen (O*), which resulted in consecutive formation of ROS. This study provides new insight on the lattice oxygen activation mechanism of silver bismuthate and its application to the remediation of polluted waters.

Simulation-Based Training of Non-Technical Skills in Colonoscopy: Protocol for a Randomized Controlled Trial

Background

Non-technical skills (NTS), such as communication and professionalism, contribute to the safe and effective completion of procedures. NTS training has previously been shown to improve surgical performance. Moreover, increases in NTS have been associated with improved clinical endoscopic performance. Despite this evidence, NTS training has not been tested as an intervention in endoscopy.

Objective

The aim of this study is to evaluate the effectiveness of a simulation-based training (SBT) curriculum of NTS on novice endoscopists’ performance of clinical colonoscopy.

Methods

Novice endoscopists were randomized to 2 groups. The control group received 4 hours of interactive didactic sessions on colonoscopy theory and 6 hours of SBT. Hours 5 and 6 of the SBT were integrated scenarios, wherein participants interacted with a standardized patient and nurse, while performing a colonoscopy on the virtual reality (VR) simulator. The NTS (intervention) group received the same teaching sessions but the last hour was focused on NTS teaching. The NTS group also reviewed a checklist of tasks relevant to NTS concepts prior to each integrated scenario case and was provided with dedicated feedback on their NTS performance during the integrated scenario practice. All participants were assessed at baseline, immediately after training, and 4 to 6 weeks post-training. The primary outcome measure is colonoscopy-specific performance in the clinical setting.

Results

In total, 42 novice endoscopists completed the study. Data collection and analysis is ongoing. We anticipate completion of all assessments by August 2017. Data analysis, manuscript writing, and subsequent submission for publication is expected to be completed by December 2017.

Conclusions

Results from this study may inform the implementation of NTS training into postgraduate gastrointestinal curricula. NTS curricula may improve attitudes towards patient safety and self-reflection among trainees. Moreover, enhanced NTS may lead to superior clinical performance and outcomes in colonoscopy.

Trial Registration

Clinicaltrial.gov NCT02877420; https://www.clinicaltrials.gov/ct2/show/NCT02877420 (Archived by WebCite at http://www.webcitation.org/6rw94ubXX NCT02877420)

Genomic Alterations and Outcomes with VEGF-Targeted Therapy in Patients with Clear Cell Renal Cell Carcinoma

Background: Mutations in VHL, PBRM1, SETD2, BAP1, and KDM5C are common in clear cell renal cell carcinoma (ccRCC), and presence of certain mutations has been associated with outcomes in patients with non-metastatic disease. Limited information is available regarding the correlation between genomic alterations and outcomes in patients with metastatic disease, including response to VEGF-targeted therapy.

Objective: To explore correlations between mutational profiles and cancer-specific outcomes, including response to standard VEGF-targeted agents, in patients with metastatic cc RCC.

Methods: A retrospective review of 105 patients with metastatic ccRCC who had received systemic therapy and had targeted next-generation sequencing of tumors was conducted. Genomic alterations were correlated to outcomes, including overall survival and time to treatment failure to VEGF-targeted therapy.

Results: The most frequent mutations were detected in VHL (83%), PBRM1 (51%), SETD2 (35%), BAP1 (24%), KDM5C (16%), and TERT (14%). Time to treatment failure with VEGF-targeted therapy differed significantly by PBRM1 mutation status (p = 0.01, median 12.0 months for MT versus 6.9 months for WT) and BAP1 mutation status (p = 0.01, median 6.4 months for MT versus 11.0 months for WT). Shorter overall survival was associated with TERT mutations (p = 0.03, median 29.6 months for MT versus 52.6 months for WT) or BAP1 mutations (p = 0.02, median 28.7 months for MT versus not reached for WT).

Conclusions: Genomic alterations in ccRCC tumors have prognostic implications in patients with metastatic disease. BAP1 and TERT promoter mutations may be present in higher frequency than previously thought, and based on this data, deserve further study for their association with poor prognosis.

Reductive dechlorination of carbon tetrachloride by bioreduction of nontronite

Reductive dechlorination of carbon tetrachloride (CT) was investigated during bioreduction of iron-containing clay mineral (i.e., nontronite) by iron-reducing bacteria (Shewanella putrefaciens CN32 (CN32)). In the absence of CT, the production of Fe(II) significantly increased in nontronite suspension with CN32 in 124 d (11.1% of Fe(III) reduction), resulting in formation of new secondary Fe(II) mineral phase (i.e., vivianite (Fe^II₃(PO₄)₂·8H₂O)). In the presence of CT, an acceleration of CT dechlorination was observed after 13 d and it reached almost 68% of removal efficiency at 32 d in nontronite suspension with CN32, which was 1.8 times higher than that by CN32 alone (37%). Significant amounts of formate (30.1%) and CO (2.4%) were measured during the CT dechlorination in the nontronite suspension with CN32. Results obtained from Fe(II) measurement and X-ray diffraction (XRD) showed the acceleration of Fe(II) production after 13 d and the formation of vivianite in the range of 13-25 d, suggesting that the biogenic vivianite enhanced the CT dechlorination in this study. Experimental results from batch kinetic tests, Fe(II) measurements, XRD analysis, and by-product study suggested that the formation of vivianite can play a crucial role for the enhanced reductive dechlorination of CT in phosphorous enriched subsurface environments with iron-containing clay minerals.