Assessment of dental implant surface stability at the nanoscale level

ObjectivesTo study the oxide layer stability of certified dental implants of system "P", made based on TiO₂ alloy with carbon coating. To perform a comparative statistical analysis of the obtained data with the available data for the dental implants of systems "A" and "B".MethodsX-ray microtomography and X-ray fluorescence analysis were used to study soft tissue biopsy specimens. Supernatants were studied by dynamic light scattering and transmission electron microscopy when simulating free emission of nanoscale metal oxide particles from the surface of dental implants as well as when simulating physical loading. A comparative analysis of three parameters of nanoscale particles was performed by statistical data analysis. The surface of the "P" system dental implant with surface treatment was analyzed by scanning electron microscopy.ResultsBoth free emission of nanoscale oxide layer particles and yield of nano- and microscale particles during simulation of physical load were confirmed. Statistically significant differences were noted in a comparative analysis of the size and frequency of occurrence of these particles in the supernatants obtained from the surfaces of three dental implant systems. The elemental composition of the particles and the composition and structure of the "P" system dental implants themselves were analyzed.SignificanceThe developed method of dynamic light scattering can be used to compare the stability of the oxide layer of standardized medical products manufactured on the basis of the TiO₂ alloy.     

Facilitators and barriers to developmentally supportive care for preterm infants in low and middle-income countries: A scoping review

BackgroundPreterm birth and its associated complications are a major cause of neonatal mortality worldwide. Approximately 15 million preterm infants are born annually, most births occurring in Sub-Saharan Africa and South Asia. However, Developmentally Supportive Care—an evidence-based intervention reported to improve the survival of preterm infants, is under utilized in Low and Middle-Income Countries. This review focuses on examining the barriers to, and facilitators of, Kangaroo Mother Care, positioning (nesting and swaddling), and control of the external neonatal intensive care environment in low- and middle-income countries.MethodsSix databases were systematically searched between January 2000 to April 2020. A search of the grey literature was also conducted. Two independent reviewers screened the citations of the retrieved papers and abstracted data for included studies based on predetermined inclusion/exclusion criteria.ResultsA total of 15853 articles were retrieved from the search. A full-text review was conducted on 155 articles. Thirty-two papers were identified and included in the review. Thirty papers focussed on KMC, two papers focused on noise control. No studies were identified on positioning and light control in the NICU. Barriers identified included lack of knowledge of DSC practices in both health care workers and family caregivers, existing cultural norms, and the absence of protocols and guidelines for practice. Facilitators included; healthcare worker training, leadership and support from health care facility managers to family caregivers, and available infrastructure.ConclusionFurther studies that comprehensively examine DSC implementation in Low-Middle-Income countries are required in order to improve sustained DSC practices.     

Weekly and seasonal variation in the circadian melatonin rhythm in humans: A response

We read with interest the commentary by Skeldon and Dijk about our article “Weekly, seasonal and chronotype-dependent variation of dim light melatonin onset.” The discussion points raised by Skeldon and Dijk are currently among the most hotly debated in human circadian science. What external factors determine human phase of entrainment? How great is the contribution of natural versus artificial light and sun time versus social time? Our intra-individual data add to the still limited evidence from field studies in this matter. In their commentary, Skeldon and Dijk formulate two either-or hypotheses, postulating that humans entrain either solely to the natural light-dark cycle (sun time referenced by midday) (H₁) or solely to the light selected by local clock time and social constraints (H₂). Neither hypothesis accounts for the effect of season on human light exposure. We interpreted our findings along more complex lines, speculating that the 1-h earlier melatonin rise in summer found in our sample is likely the combined result of daylight saving time (DST)-induced behavioral advances and a stronger natural zeitgeber in summer (light exposure determined by social and seasonal factors, H_original). Here, we show how the criticism by Skeldon and Dijk is based on two sentences quoted out of context (misrepresenting our hypothesis as H₁) and that their hypothesis H₂ leaves out important seasonal components in light exposure.     

Social cognitive correlates of device-measured and self-reported physical activity in Black and White individuals with multiple sclerosis

BackgroundThere is increasing research interest regarding physical activity behavior among persons with multiple sclerosis (MS), yet there is little known about physical activity and its correlates in Black persons with MS.ObjectiveThis cross-sectional study assessed associations among social cognitive theory (SCT) variables and device-measured and self-reported physical activity in samples of Black and White persons with MS.MethodsParticipants included 67 Black and 141 White persons with MS who wore an ActiGraph accelerometer on a belt around the waist measuring moderate-to-vigorous physical activity (MVPA) for seven days and completed a battery of questionnaires. Questionnaires included demographic and clinical characteristics, leisure-time exercise, exercise self-efficacy, overcoming barriers self-efficacy, function, social support, exercise outcome expectations, and goal setting and planning.ResultsBlack participants with MS engaged in significantly less MVPA, but not sedentary behavior or light physical activity, than the White participants with MS. Black participants further had significantly lower levels of exercise self-efficacy and outcome expectations than the White sample. All SCT correlates were significantly correlated with self-reported physical activity, but only exercise and barriers self-efficacy, perceived function, and exercise goal setting were associated with device-measured MVPA. The difference in physical activity between Black and White participants with MS was accounted for by differences in exercise self-efficacy and outcome expectations.ConclusionsResearchers should consider developing behavioral interventions that target exercise self-efficacy and outcome expectations as SCT variables for increasing physical activity in Black persons with MS.     

Phytophotodermatitis

Phytophotodermatitis is a phototoxic cutaneous eruption due to skin exposure to furocourmarins combined with ultraviolet light. Bizzare linear patterns, ranging from erythema to bullae with residual hyperpigmentaion, is the clinical clue to this diagnosis. Avoidance of furocoumarins in direct sunlight can prevent recurrences.