Controlled Differentiation of Human Neural Progenitor Cells on Molybdenum Disulfide/Graphene Oxide Heterojunction Scaffolds by Photostimulation.

Ultrathin MoS2-MoO3-x heterojunction nanosheets with unique features were introduced as biocompatible, non-cytotoxic, and visible light-sensitive stimulator layers for the controlled differentiation of human neural progenitor cells (hNPCs) into nervous lineages. hNPC differentiation was also investigated on reduced graphene oxide (rGO)-containing scaffolds, that is, rGO and rGO/MoS2-MoO3-x nanosheets. In darkness, hNPC differentiation into neurons increased on MoS2-MoO3-x by a factor of 2.7 due to the excellent biophysical cues and further increased on rGO/MoS2-MoO3-x by a factor of 4.4 due to a synergistic effect induced by the rGO. The MoO3-x domains with antioxidant activity and LSPR absorption induced p-type doping in MoS2-MoO3-x. Under photostimulation, the hNPCs on the MoS2-MoO3-x exhibited higher differentiation into glial cells by a factor of 1.4, and the decrease in photo-electron current to hNPCs due to the induction of more p-type doping in the MoS2-MoO3-x. While the increase in neuronal differentiation of hNPCs on rGO/MoS2-MoO3-x by a factor of 1.8 was ascribed to the presence of rGO as an ultrafast electron transferor which quickly transferred photogenerated electrons to hNPCs before their transfer to free radicals, these results demonstrated the promising potential of MoS2-based scaffolds for applying in the controllable repair and/or regeneration of diseases/disorders related to the nervous system.

Current knowledge of physicians' dual practice in Iran: A scoping review and defining the research agenda for achieving universal health coverage.

BACKGROUND: Physicians' dual practice (simultaneous practice in both public and private sectors) may be challenging for achieving universal health coverage. The purpose of this review is to identify the types of available evidence in physicians' dual practice in Iran and define the research agenda for achieving universal health coverage (UHC). METHODS: We conducted a scoping review of the literature using Arksey and O'Malley's approach. We searched Embase, PubMed, the Cochrane Library, Scopus, Web of Science core collection, as well as internal databases including the National Magazine Database (Magiran) and the Scientific Information Database (SID) until August 3, 2020. Studies published in Persian or English and investigating physicians' dual practice in the health system of Iran were included. Each step of the study was performed by two of the present researchers. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) recommendations were used to conduct this study and report the findings. RESULTS: Fourteen studies were included in the current review. The findings were categorized and synthesized into five themes including the forms of dual practice, the extent of dual practice, the motivators and factors affecting dual practice, the policy options, and the consequences of dual practice. There were limited evidence on the nature, types, and prevalence of this phenomenon for different provinces and medical specialties and on health policy options in Iran. There seems to be a methodological gap (a gap in the type of study and its method) in the subject area. Most studies have only used quantitative or qualitative study methods and based on the self-report of research samples in most of the included studies. CONCLUSIONS: More research is required at national level on the nature, types, and prevalence of this phenomenon, focusing on clarifying the root causes of this phenomenon and on the effects of dual practice on the indicators of accessibility to health services, especially for vulnerable populations, the quality of care provided, and equity, and on complex policy research on health policy options in Iran. The research questions proposed in the present study can help to bridge the knowledge gap in this area. Additional studies should address issues related to the quality of data collection in physicians' dual practice.

The effects of beta-cell mass and function, intercellular coupling, and islet synchrony on [Formula: see text] dynamics.

Type 2 diabetes (T2D) is a challenging metabolic disorder characterized by a substantial loss of [Formula: see text]-cell mass and alteration of [Formula: see text]-cell function in the islets of Langerhans, disrupting insulin secretion and glucose homeostasis. The mechanisms for deficiency in [Formula: see text]-cell mass and function during the hyperglycemia development and T2D pathogenesis are complex. To study the relative contribution of [Formula: see text]-cell mass to [Formula: see text]-cell function in T2D, we make use of a comprehensive electrophysiological model of human [Formula: see text]-cell clusters. We find that defect in [Formula: see text]-cell mass causes a functional decline in single [Formula: see text]-cell, impairment in intra-islet synchrony, and changes in the form of oscillatory patterns of membrane potential and intracellular [Formula: see text] concentration, which can lead to changes in insulin secretion dynamics and in insulin levels. The model demonstrates a good correspondence between suppression of synchronizing electrical activity and published experimental measurements. We then compare the role of gap junction-mediated electrical coupling with both [Formula: see text]-cell synchronization and metabolic coupling in the behavior of [Formula: see text] concentration dynamics within human islets. Our results indicate that inter-[Formula: see text]-cellular electrical coupling depicts a more important factor in shaping the physiological regulation of islet function and in human T2D. We further predict that varying the whole-cell conductance of delayed rectifier [Formula: see text] channels modifies oscillatory activity patterns of [Formula: see text]-cell population lacking intercellular coupling, which significantly affect [Formula: see text] concentration and insulin secretion.

Graphene Jet Nanomotors in Remote Controllable Self-Propulsion Swimmers in Pure Water.

A remote controllable working graphite nanostructured swimmer based on a graphene jet nanomotor has been demonstrated for the first time. Graphite particles with pyramidal-like morphologies were fabricated by the creation of suitable defects in wide high-purity graphite flakes followed by a severe sonication. The particles were able to be self-exfoliated in water after Na intercalation between the graphene constituents. The self-exfoliation resulted in jet ejection of graphene flakes from the end of the swimmers (with speeds as high as ∼7000 m/s), producing a driving force (at least ∼0.7 L (pN) where L (µm) is swimmer size) and consequently the motion of the swimmer (with average speed of ∼17-40 µm/s). The jet ejection of the graphene flakes was assigned to the explosion of H2 nanobubbles produced between the Na intercalated flakes. The direction of motion of the swimmers equipped with TiO2 nanoparticles (NPs) can be controlled by applying a magnetic field in the presence of UV irradiation (higher UV intensity, lower radius of rotation). In fact, the negative surface charge of the graphene flakes of the swimmers increased by UV irradiation due to transferring the photoexcited electrons of TiO2 NPs into the flakes. Because of higher production of H2 nanobubbles under UV irradiation, the speed of swimmers exposed to UV light significantly increased. In contrast, UV irradiation with various intensities could not affect total distance traversed by the self-exfoliated swimmers having the same initial sizes. These confirmed the mass ejection mechanism for motion of the swimmers. The self-exfoliation of swimmers (and so their motion) occurred only in water (and not, e.g., in organic solutions). Such swimmers promise the design of remote controllable nanovehicles with the capability of initiating and/or improving their operations in response to environmental changes in order to realize broad ranges of versatile and fantastic nanotechnology-based applications.