Carbon–semiconductor hybrid quantum dots are classical carbon dots with core carbon nanoparticles doped with a selected nanoscale semiconductor. Specifically, on those with the nanoscale TiO2 doping, ...denoted as CTiO2-Dots, their synthesis and thorough characterization were reported previously. In this work, the CTiO2-Dots were evaluated for their visible light-activated antibacterial function, with the results showing the effective killing of not only Gram-positive but also the generally more resistant Gram-negative bacteria. The hybrid dots are clearly more potent antibacterial agents than their neat carbon dot counterparts. Mechanistically, the higher antibacterial performance of the CTiO2-Dots is attributed to their superior photoexcited state properties, which are reflected by the observed much brighter fluorescence emissions. Also considered and discussed is the possibility of additional contributions to the antibacterial activities due to the photosensitization of the nanoscale TiO2 by its doped core carbon nanoparticles.
Carbon dots (CDots) exploit and enhance the intrinsic properties of small carbon nanoparticles. Their optical absorptions and photoinduced redox characteristics are competitive with those of ...conventional semiconductor quantum dots at one end and fullerenes and other carbon nanomaterials at the other. Highlighted in this mini review are the effective photon harvesting over a broad spectral range by CDots and their subsequent excited-state charge transfer processes and interactions, which have enabled their use as sensors, for photodynamic effects, and in various energy conversion technologies.
•Radiomics signature based on contrast-enhanced CT for prediction of disease-freesurvival in colorectal cancer patients with liver metastasis can be constructed withmachine learning algorithms.•The ...prognostic role of both radiomics signatures can be demonstrated with Coxregression and Kaplan-Meier analyses by external validation.•Radiomics signatures by two different machine learning algorithms show comparable stratification performance.
The liver is the most common organ for the formation of colorectal cancer metastasis. Non-invasive prognostication of colorectal cancer liver metastasis (CRLM) may better inform clinicians for decision-making. Contrast-enhanced computed tomography images of 180 CRLM cases were included in the final analyses. Radiomics features, including shape, first-order, wavelet, and texture, were extracted with Pyradiomics, followed by feature engineering by penalized Cox regression. Radiomics signatures were constructed for disease-free survival (DFS) by both elastic net (EN) and random survival forest (RSF) algorithms. The prognostic potential of the radiomics signatures was demonstrated by Kaplan-Meier curves and multivariate Cox regression. 11 radiomics features were selected for prognostic modelling for the EN algorithm, with 835 features for the RSF algorithm. Survival heatmap indicates a negative correlation between EN or RSF risk scores and DFS. Radiomics signature by EN algorithm successfully separates DFS of high-risk and low-risk cases in the training dataset (log-rank test: p < 0.01, hazard ratio: 1.45 (1.07–1.96), p < 0.01) and test dataset (hazard ratio: 1.89 (1.17–3.04), p < 0.05). RSF algorithm shows a better prognostic implication potential for DFS in the training dataset (log-rank test: p < 0.001, hazard ratio: 2.54 (1.80–3.61), p < 0.0001) and test dataset (log-rank test: p < 0.05, hazard ratio: 1.84 (1.15–2.96), p < 0.05). Radiomics features have the potential for the prediction of DFS in CRLM cases.
Clinical trials examining the therapeutic benefit of modafinil in MS fatigue provide conflicting data. The goal of this study was to systematically evaluate the efficacy of modafinil using a ...meta-analytic method.
A systematic literature search was performed on published peer reviewed articles from 2000 to 2017 using the Cochrane Library, PubMed, and EMBASE. This review included double blind, randomized controlled trials, which evaluated modafinil in MS fatigue. The primary outcome measure was the estimated treatment difference in the Modified Fatigue Impact Scale score (MFIS) and Fatigue Severity Scale score (FSS). A secondary outcome measure was the estimated treatment difference in the Symbol Digit Modalities Test (SDMT).
A total of 303 patients from five randomized controlled trials were included in the analyses. Modafinil was superior to placebo with an estimated treatment difference according to the MFIS (MD = −5.27, 95% CI: −8.51 to −2.03, P = 0.001). For the FSS, there was no significant difference between the two groups (MD = 2.50, 95%CI: −0.70 to 5.70, P = 0.13). For the secondary outcome, there was no significant difference between groups studied using the SDMT (MD = 0.23, 95% CI: −0.25 to 0.71, P = 0.35).
Our meta-analysis showed that modafinil was an effective pharmacologic therapy for MS fatigue. Additional research is required to determine optimal dosing and treatment schedules.
•The benefit of modafinil in multiple sclerosis fatigue is controversial.•We included a comprehensive collection of RCTs in this analysis.•Modafinil is an effective pharmacologic therapy for multiple sclerosis fatigue.
Under hard acceleration or on a hill climb of (hybrid) electronic vehicles, the battery temperature would increase rapidly. High temperature decreases the battery cycle life, increases the thermal ...runaway, and even causes a battery to explode, that making the management of battery temperature an important consideration in the safety using of electronic vehicles. A study of increasing heat transfer area from the beginning design phase has been conducted to determine and enhance the heat dissipation on the battery surface. Both experiment and simulation methods were used to analyze the cooling performance under identical battery capacities and heights. Optimal external dimensions and cell sizes with the consideration of better battery workability was obtained from the analysis. The heat transfer coefficients were investigated in order to regulate the battery temperature under safety operating range. It was found that the temperature of the experiment battery would be controlled under safety critical when the cell was designed for 180 mm × 30 mm × 185 mm sizes and the surface heat transfer coefficient was 20 W m
−2
K
−1
at least.
Carbon dots were originally found and reported as surface-passivated small carbon nanoparticles, where the effective surface passivation was the chemical functionalization of the carbon nanoparticles ...with organic molecules. Understandably, the very broad optical absorptions of carbon dots are largely the same as those intrinsic to the carbon nanoparticles, characterized by progressively decreasing absorptivities from shorter to longer wavelengths. Thus, carbon dots are generally weak absorbers in the red/near-IR and correspondingly weak emitters with low quantum yields. Much effort has been made on enhancing the optical performance of carbon dots in the red/near-IR, but without meaningful success due to the fact that optical absorptivities defined by Mother Nature are in general rather inert to any induced alterations. Nevertheless, there were shockingly casual claims in the literature on the major success in dramatically altering the optical absorption profiles of "carbon dots" by simply manipulating the dot synthesis to produce samples of some prominent optical absorption bands in the red/near-IR. Such claims have found warm receptions in the research field with a desperate need for carbon dots of the same optical performance in the red/near-IR as that in the green and blue. However, by looking closely at the initially reported synthesis and all its copies in subsequent investigations on the "red/near-IR carbon dots", one would find that the "success" of the synthesis by thermal or hydrothermal carbonization processing requires specific precursor mixtures of citric acid with formamide or urea. In the study reported here, the systematic investigation included precursor mixtures of citric acid with not only formamide or urea but also their partially methylated or permethylated derivatives for the carbonization processing under conditions similar to and beyond those commonly used and reported in the literature. Collectively all of the results are consistent only with the conclusion that the origins of the observed red/near-IR optical absorptions in samples from some of the precursor mixtures must be molecular chromophores from thermally induced chemical reactions, nothing to do with any nanoscale carbon entities produced by carbonization.
The thermal processing of specific precursor mixtures under relatively mild conditions does not result in "red/near-IR carbon dots" as previously claimed, but instead chemical reactions for molecular chromophores of red/near-IR absorptions.
The commercially acquired aqueous solution of “carbon quantum dots” sample was evaluated by optical absorption and fluorescence emission methods; in reference to aqueous dispersed small carbon ...nanoparticles and representative carbon dots prepared from chemical functionalization of the carbon nanoparticles. The results suggest a very low content of carbon that is associated with nanoscale carbon particles/domains in the as-supplied sample; and likely significant contamination by dye-like species/mixtures. In the absence of any information on the synthesis and history of the commercial sample, the possible cause of the contamination was illustrated by an example on similar dye formation in the one-pot carbonization synthesis of “red carbon dots” from citric acid–formamide precursor mixtures under too mild processing conditions that were insufficient for the intended carbonization. The negative impacts to the carbon dots research field by the apparent proliferation and now commercial availability of carbon-deficient or even largely carbon-less “carbon quantum dots”, which are more susceptible to dye contamination or dominance, are discussed.
The carbon/TiO2 hybrid dots (C/TiO2-Dots) are structurally TiO2 nanoparticles (in the order of 25 nm in diameter from commercially available colloidal TiO2 samples) surface-attached by nanoscale ...carbon domains with organic moieties, thus equivalent to hybrids of individual TiO2 nanoparticles each decorated with many carbon dots. These hybrid dots with exposure to visible light exhibit potent antibacterial properties, similar to those found in neat carbon dots with the same light activation. The results from the use of established scavengers for reactive oxygen species (ROS) to “quench” the antibacterial activities, an indication for shared mechanistic origins, are also similar. The findings in experiments on probing biological consequences of the antibacterial action suggest that the visible light-activated C/TiO2-Dots cause significant damage to the bacterial cell membrane, resulting in higher permeability, with the associated oxidative stress leading to lipid peroxidation, inhibiting bacterial growth. The induced bacterial cell damage could be observed more directly in the transmission electron microscopy (TEM) imaging. Opportunities for the further development of the hybrid dots platform for a variety of antibacterial applications are discussed.
Carbon dots (CDots) are small carbon nanoparticles with effective surface passivation by organic functionalization. In the reported work, the surface functionalization of preexisting small carbon ...nanoparticles with N-ethylcarbazole (NEC) was achieved by the NEC radical addition. Due to the major difference in microwave absorption between the carbon nanoparticles and organic species such as NEC, the nanoparticles could be selectively heated via microwave irradiation to enable the hydrogen abstraction in NEC to generate NEC radicals, followed by in situ additions of the radicals to the nanoparticles. The resulting NEC-CDots were characterized by microscopy and spectroscopy techniques including quantitative proton and 13C NMR methods. The optical spectroscopic properties of the dot sample were found to be largely the same as those of CDots from other organic functionalization schemes. The high structural stability of NEC-CDots benefiting from the radical addition functionalization is highlighted and discussed.
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