The use of acoustic microscopy to study the mechanical properties of glass-ionomer cement.

OBJECTIVES: The aim of the study was to investigate the relationship between microstructure, acoustic and mechanical properties of hardened dental cement samples, prepared with different powder/water ratios. METHODS: Glass-ionomer dental cement samples, prepared with a standard amount of cement powder and different amounts of water have been examined after being hardened. Surface microstructure and ultrasound, longitudinal and shear velocities were obtained with a scanning acoustic microscope. Conditional effective elastic modulus and Poisson's ratio have been calculated using longitudinal and shear sound velocity values. Then on the same samples elastic modulus and microhardness have been determined by standard tests. Additional samples have been used to determine compressive strength. RESULTS: Density; conditionally instantaneous elastic modulus; high-elasticity modulus and compression strength of the samples decrease when large amounts of water were used for their preparation. At the same time porosity and microhardness of the cement matrix increase. Acoustic parameters and parameters of elasticity, calculated on the basis of sound velocity, demonstrated changes, similar to those obtained in standard mechanical tests. SIGNIFICANCE: The established relation between microstructure, acoustic and mechanical parameters demonstrated a high capacity of acoustic microscopy application for non-destructive characterization of dental materials. A particular advantage of the acoustic microscopy is the opportunity to evaluate microstructure and mechanical properties on the same sample.     

Teacher Evaluation of an Experiential Vegetable Education Program for Australian Primary Schools: Does Face-to-Face Training Add Value above Digital Training?

The teacher-led implementation of healthy eating programs in schools is cost-effective and potentially impactful. Teacher acceptability is important for uptake; however, process evaluations are scarce. This study evaluated the effect of two intensities of teacher training on the evaluation of a vegetable education program for Australian primary schools by teachers. The teachers (n = 65) who implemented the program as part of a cluster RCT (25 schools in two states, New South Wales and South Australia) received either low- (provision with materials and online training) or high (additional face-to-face (F2F) training)-intensity training prior to implementing a 5-week vegetable education program. They evaluated the acceptability of a digital training module and program by indicating the level of agreement with 15 and 18 statements, respectively, using 5-point Likert scales. The average item scores ranged from 3.0 to 4.2. All but one item, including student engagement, alignment to the curriculum and intent for reuse of the program, had a rounded average or median score of 4. The level of training intensity did not impact the teacher acceptability ratings. In conclusion, the teacher acceptability was good, and additional F2F training does not add value above the solely digital training of the teachers.     

Cannabinoid hyperemesis syndrome in two French emergency departments: a prospective cohort

Chronic cannabis use can be associated with uncontrollable vomiting and abdominal pain. Diagnostic criteria for cannabinoid hyperemesis syndrome (CHS) were defined in 2012 by Simonetto et al. The objectives of this study were to describe the prevalence of CHS, the patients' epidemiological characteristics, and to show the difficulties encountered in caring for these patients in emergency departments, the extent of health care and an unsuitable follow‐up in general practices. A prospective cohort of patients with CHS was recruited among a target population of patients leaving the adult emergency services of the Marseille hospitals Nord and La Timone between October 2017 and July 2018, with abdominal pain syndrome of unidentified etiology. Inclusion criteria for the CHS cohort were chronic cannabis use associated with nausea and vomiting. There were 48 patients included in the CHS cohort who took cannabis daily, in a target population of 2 848 patients (i.e. 1.6%). A hot shower was the most effective symptomatic treatment in 54.2% of cases. Patients suffering from CHS spent significantly more hours in emergency departments (11 vs. 6.5), and, on average, visits were more frequent (4.9 vs. 3). 20.3% of them were hospitalized to continue pain medication. Once out of hospital, follow‐up was limited, and weaning off cannabis, the only etiological treatment, was difficult to set up. Informing patients about CHS is essential, and a hot shower could be systematically proposed, thus limiting an unnecessary extent of health care. CHS is genuine, medical staff should be made aware of it in occupational training, and it should be seriously considered in health policies.     

Autophagy is required for CSF-1-induced macrophagic differentiation and acquisition of phagocytic functions

Autophagy is the process by which superfluous or damaged macromolecules or organelles are degraded by the lysosome. Pharmacologic and genetic evidence indicates that autophagy plays pleiotropic functions in cellular homeostasis, development, survival, and differentiation. The differentiation of human blood monocytes into macrophages is a caspase-dependent process when triggered ex vivo by colony stimulating factor-1. We show here, using pharmacologic inhibitors, siRNA approaches, and Atg7-/- mice, that autophagy initiated by ULK1 is required for proper colony stimulating factor-1-driven differentiation of human and murine monocytes. We also unravel a role for autophagy in macrophage acquisition of phagocytic functions. Collectively, these findings highlight an unexpected and essential role of autophagy during monocyte differentiation and acquisition of macrophage functions.     

New data on histology and physico-mechanical properties of human tooth tissue obtained with acoustic microscopy

Quantitative evaluation of human tooth structural elements, revealed in acoustic images, has been carried out. It has been shown that tissue elements with different acoustic impedances differed in acoustic images by intensity of grey color, and also feature with different longitudinal sound velocities (C(L)). In the layer of mantle dentin, C(L) is 7% to 8% lower than in bulk dentin, and in the layer of dentin around the pulp chamber, C(L) is 15% lower. In carious enamel and dentin, C(L) decreases up to 7% to 17%. In pathologic teeth, dentin areas with higher density can be revealed; they feature higher C(L); in transparent dentin C(L) can be 15% to 20% higher than in bulk dentin. Results of the present study show that acoustic images reflect internal biomechanical properties of tooth tissue microstructure that can be evaluated quantitatively by means of longitudinal sound velocity determination.