Novel strategies utilizing magnetic nanoparticles (MNPs) and magnetic fields are being developed to enhance bone tissue engineering efficacy. This article first reviewed cutting-edge research on the ...osteogenic enhancements via magnetic fields and MNPs. Then the current developments in magnetic strategies to improve the cells, scaffolds and growth factor deliveries were described. The magnetic-cell strategies included cell labeling, targeting, patterning, and gene modifications. MNPs were incorporated to fabricate magnetic composite scaffolds, as well as to construct delivery systems for growth factors, drugs and gene transfections. The novel methods using magnetic nanoparticles and scaffolds with magnetic fields and stem cells increased the osteogenic differentiation, angiogenesis and bone regeneration by 2–3 folds over those of the controls. The mechanisms of magnetic nanoparticles and scaffolds with magnetic fields and stem cells to enhance bone regeneration were identified as involving the activation of signaling pathways including MAPK, integrin, BMP and NF-κB. Potential clinical applications of magnetic nanoparticles and scaffolds with magnetic fields and stem cells include dental, craniofacial and orthopedic treatments with substantially increased bone repair and regeneration efficacy.
We observe signatures of radial and angular roton excitations around a droplet crystallization transition in dipolar Bose-Einstein condensates. In situ measurements are used to characterize the ...density fluctuations near this transition. The static structure factor is extracted and used to identify the radial and angular roton excitations by their characteristic symmetries. These fluctuations peak as a function of the interaction strength indicating the crystallization transition of the system. We compare our observations to a theoretically calculated excitation spectrum allowing us to connect the crystallization mechanism with the softening of the angular roton modes.
The association between long-term exposure to ambient fine particulate matter with aerodynamic diameter
(
) and lung function in young people remains uncertain, particularly in Asia, where air ...pollution is generally a serious problem.
This study investigated the association between long-term exposure to ambient
and lung function in Taiwanese children, adolescents, and young adults.
This study comprised 24,544 participants 6-24 years of age, with 33,506 medical observations made between 2000 and 2014. We used a spatiotemporal model to estimate
concentrations at participants' addresses. Spirometry parameters, i.e., forced vital capacity (FVC), forced expiratory volume in 1 s (
), and maximum midexpiratory flow (MMEF), were determined. A generalized linear mixed model was used to examine the associations between long-term exposure to ambient
and lung function. The odds ratios (ORs) of poor lung function were also calculated after adjusting for a range of covariates.
Every
increase in the 2-y average
concentration was associated with decreases of 2.22% 95% confidence interval (CI):
,
, 2.94 (95% CI:
,
), and 2.79% (95% CI:
,
) in the FVC,
, and MMEF, respectively. Furthermore, it was associated with a 20% increase in the prevalence of poor lung function (OR: 1.20; 95% CI: 1.12, 1.29).
Two-year ambient
concentrations were inversely associated with lung function and positively associated with the prevalence of poor lung function in children, adolescents, and young adults in Taiwan. https://doi.org/10.1289/EHP5220.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The toxicity of metal oxide nanomaterials and their antimicrobial activity is attracting increasing attention. Among these materials, MgO is particularly interesting as a low cost, ...environmentally‐friendly material. The toxicity of MgO, similar to other metal oxide nanomaterials, is commonly attributed to the production of reactive oxygen species (ROS). We investigated the toxicity of three different MgO nanoparticle samples, and clearly demonstrated robust toxicity towards Escherichia coli bacterial cells in the absence of ROS production for two MgO nanoparticle samples. Proteomics data also clearly demonstrate the absence of oxidative stress and indicate that the primary mechanism of cell death is related to the cell membrane damage, which does not appear to be due to lipid peroxidation.
Robust antibacterial activity on Escherichia coli cells in the absence of ROS production is demonstrated. Multiple lines of evidence clearly show the absence of oxidative stress and indicate that the primary mechanism of cell death is related to cell membrane damage, which does not appear to be due to lipid peroxidation.
Contact resistance limits the performance of organic field‐effect transistors, especially those based on high‐mobility semiconductors. Despite intensive research, the nature of this phenomenon is not ...well understood and mitigation strategies are largely limited to complex schemes often involving co‐evaporated doped interlayers. Here, this study shows that solution self‐assembly of a polyelectrolyte monolayer on a metal electrode can induce carrier doping at the contact of an organic semiconductor overlayer, which can be augmented by dopant ion‐exchange in the monolayer, to provide ohmic contacts for both p‐ and n‐type organic field‐effect transistors. The resultant 2D‐doped profile at the semiconductor interface is furthermore self‐aligned to the contact and stabilized against counterion migration. This study shows that Coulomb potential disordering by the polyelectrolyte shifts the semiconductor density‐of‐states into the gap to promote extrinsic doping and cascade carrier injection. Contact resistivities of the order of 0.1–1 Ω cm2 or less have been attained. This will likely also provide a platform for ohmic injection into other advanced semiconductors, including 2D and other nanomaterials.
Solution self‐assembly of a polyelectrolyte monolayer on a metal electrode can induce carrier doping at the contact of a semiconductor overlayer, which can be augmented by dopant ion‐exchange in the monolayer to provide ohmic contacts for both p‐ and n‐type organic field‐effect transistors. Contact resistivities of the order of 0.1–1 Ω cm2 have been attained. The resultant 2D‐doped profile is stabilized against counterion migration.
A novel conducting sulphur-polypyrrole composite material was prepared by the chemical polymerization method with sodium
p-toluenesulphonate as the dopant, 4-styrenesulphonic sodium salts as the ...surfactant, and FeCl
3 as the oxidant. The new material was characterized by Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Nanosize polypyrrole particles were uniformly coated onto the surface of the sulphur powder, which significantly improved the electrical conductivity, the capacity and the cycle durability in a lithium cell compared with the bare sulphur electrode.
After curative radiotherapy (RT) or chemoradiation (CRT), there is no validated tool to accurately identify patients for adjuvant therapy in nasopharyngeal carcinoma (NPC). Post-RT circulating plasma ...Epstein–Barr virus (EBV) DNA can detect minimal residual disease and is associated with recurrence and survival independent of TNM (tumor–lymph node–metastasis) stage. We aimed to develop and validate a risk model for stratification of NPC patients after completion of RT/CRT to observation or adjuvant therapy.
The prospective multicenter 0502 EBV DNA screening cohort (Hong Kong NPC Study Group 0502 trial) enrolled from 2006 to 2015 (n = 745) was used for model development. For internal validation, we pooled independent patient cohorts from prospective clinical studies enrolled from 1997 to 2006 (n = 340). For external validation, we used retrospective cohort of NPC patients treated at Sun Yat-sen University Cancer Center from 2009 to 2012 (n = 837). Eligible patients had histologically confirmed NPC of Union for International Cancer Control (UICC) 7th Edition stage II–IVB who completed curative RT/CRT with or without neoadjuvant chemotherapy, had post-RT EBV DNA tested within 120 days after RT and received no adjuvant therapy. The primary end point was overall survival (OS). We used recursive-partitioning analysis (RPA) to classify patients into groups of low, intermediate, and high risk of death.
Combining post-RT EBV DNA level (0, 1–49, 50–499, and ≥500 copies/ml) and TNM stage (II, III, IVAB), RPA model classified patients into low-, intermediate-, and high-risk groups with 5-year OS of 89.4%, 78.5% and 37.2%, respectively. The RPA low-risk group had comparable OS to TNM stage II (5-year OS 88.5%) but identified more patients (64.8% versus stage II 28.1%) that could potentially be spared adjuvant therapy toxicity. The RPA model (c-index 0.712) showed better risk discrimination than either the TNM stage (0.604) or post-RT EBV DNA alone (0.675) with improved calibration and consistence. These results were validated in both internal and external cohorts.
Combining post-RT EBV DNA and TNM stage improved risk stratification in NPC.
•Integrating postradiotherapy plasma Epstein–Barr virus (EBV) DNA and tumor–lymph node–metastasis (TNM) stage improves the risk stratification of nasopharyngeal carcinoma.•Postradiotherapy plasma EBV DNA is a better predictor of early death in nasopharyngeal carcinoma than TNM stage.•The low-risk group by recursive partitioning model can spare more patients from unnecessary toxicity of adjuvant therapy.
Metformin, a first‐line antidiabetic drug used by millions of patients, has been shown to have potential osteogenic properties. The present study was performed to test the hypothesis that clinically ...relevant doses of metformin promote the osteogenic differentiation and mineralization of induced pluripotent stem cell‐derived mesenchymal stem cells (iPSC‐MSCs). iPSC‐MSCs were treated with metformin (10 μm) to assess cell viability, osteogenic differentiation, mineralization and activation of the LKB1/AMP‐activated protein kinase (AMPK) signalling pathway, a surrogate marker of metformin action. To determine its potential application in MSC‐based bone and periodontal tissue engineering, iPSC‐MSCs were also treated with metformin when seeded on to calcium phosphate cement (CPC) scaffolds. Immunoblotting and cellular uptake assays showed that iPSC‐MSCs express functional organic cation transporter‐1 (OCT‐1), a transmembrane protein that mediates the intracellular uptake of metformin. Although metformin treatment did not impair iPSC‐MSC viability, it significantly stimulated alkaline phosphatase activity, enhanced mineralized nodule formation and increased expression of osteogenic markers, including Runt‐related transcription factor 2 (RUNX2) and osterix. Inhibition of LKB1 activity, a common upstream AMPK kinase, markedly reversed metformin‐induced AMPK activation, RUNX2 expression and nuclear localization. Moreover, metformin substantially increased mineralized nodule formation of iPSC‐MSC seeded on CPC scaffolds. Collectively, functional OCT‐expressing iPSC‐MSCs responded to metformin by inducing an osteogenic effect in part mediated by the LKB1/AMPK pathway. Considering the widespread use of metformin in diabetics, this work may lead to novel tissue‐engineering platforms where autogenous OCT‐expressing iPSC‐MSCs might be used to enhance bone and periodontal regeneration in diabetic patients prescribed with daily doses of metformin.
Chinese tongue sole is a marine fish with ZW sex determination. Genome sequencing suggested that the Z-linked dmrt1 is a putative male determination gene, but direct genetic evidence is still ...lacking. Here we show that TALEN of dmrt1 efficiently induced mutations of this gene. The ZZ dmrt1 mutant fish developed ovary-like testis, and the spermatogenesis was disrupted. The female-related genes foxl2 and cyp19a1a were significantly increased in the gonad of the ZZ dmrt1 mutant. Conversely, the male-related genes Sox9a and Amh were significantly decreased. The dmrt1 deficient ZZ fish grew much faster than ZZ male control. Notably, we obtained an intersex ZW fish with a testis on one side and an ovary on the other side. This fish was chimeric for a dmrt1 mutation in the ovary, and wild-type dmrt1 in the testis. Our data provide the first functional evidence that dmrt1 is a male determining gene in tongue sole.
•Nonpharmaceutical interventions were effective in reducing COVID-19 transmission.•Social distancing is more effective than the other NPIs in containing COVID-19.•Two or more synchronous NPIs are ...more effective than a single type of NPI.
To evaluate and compare the effectiveness of four types of non-pharmaceutical interventions (NPIs) to contain the time-varying effective reproduction number (Rt) of coronavirus disease-2019 (COVID-19).
This study included 1,908,197 confirmed COVID-19 cases from 190 countries between 23 January and 13 April 2020. The implemented NPIs were categorised into four types: mandatory face mask in public, isolation or quarantine, social distancing and traffic restriction (referred to as mandatory mask, quarantine, distancing and traffic hereafter, respectively).
The implementations of mandatory mask, quarantine, distancing and traffic were associated with changes (95% confidence interval, CI) of −15.14% (from −21.79% to −7.93%), −11.40% (from −13.66% to −9.07%), −42.94% (from −44.24% to −41.60%) and −9.26% (from −11.46% to −7.01%) in the Rt of COVID-19 when compared with those without the implementation of the corresponding measures. Distancing and the simultaneous implementation of two or more types of NPIs seemed to be associated with a greater decrease in the Rt of COVID-19.
Our study indicates that NPIs can significantly contain the COVID-19 pandemic. Distancing and the simultaneous implementation of two or more NPIs should be the strategic priorities for containing COVID-19.
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