Ecotoxicity of engineered nanoparticles (NPs) has become the focus of considerable attention because of their wide applications. Reactive oxygen species (ROS) play important roles in the toxicity ...mechanisms of engineered metal oxide NPs. This work aimed to understand quantitatively the contribution of photogenerated ROS on metal oxide NPs to their toxicity. The dynamic generation of O
,
OH, and H
O
in aqueous suspensions of photoilluminated metal oxide nano- and bulk particles (TiO
, ZnO, V
O
, CeO
, Fe
O
, and Al
O
) was measured by a continuous-flow chemiluminescence (CFCL) detection system. Superoxides were generated on all six nanoparticles as well as bulk TiO
and ZnO, with nano TiO
producing the highest concentration (180 nM). Hydroxyl radicals were detected on both nano- and bulk TiO
and ZnO, whereas H
O
was detected only on TiO
and ZnO nanoparticles. The generation of ROS can in general be interpreted by the electronic structures and surface defects of the NPs and the ROS redox potentials. Furthermore, acute toxicity of the six metal oxide particles to a luminescent bacterium, P. phosphoreum 502 was assessed after photoillumination. The toxicity effect was attributed to the long-lived O
radicals on the nanoparticlce, and its potency follows the order of TiO
> ZnO > V
O
> Fe
O
> CeO
> Al
O
, which is the same as the order of the O
concentration measured by CFCL. Our work revealed quantitatively the important role superoxide radicals play in the toxicity of various metal oxide nanoparticles after photoillumination.
The Pawlak model of conflict analysis uses three-valued ratings (i.e., positive, neutral, and negative) of a set of agents on a set of issues. Several extensions to the Pawlak model, namely, rough ...sets based qualitative and quantitative models, formal concept analysis based quantitative models, and three-way conflict analysis models, have been proposed in recent years. The main objective of this paper is to propose a more general model that unifies these existing models in an evaluation-based framework of three-way decision. The proposed model uses a pair of evaluations, one for support and the other for opposition, for trisecting the set of agents. By considering qualitative and quantitative evaluations, we derive a qualitative model and a quantitative model of three-way conflict analysis, respectively. The corresponding two models built based on rough sets and the corresponding two models built based on formal concept analysis are special cases. A unification of existing models provides insights into a common structure in formulating three-way conflict analysis with different choices of evaluations. We illustrate an application of the three-way conflict analysis model in making development plans for Gansu Province in China.
► Natural sources of phenolic compounds. ► Detailed classification of polyphenols. ► Extraction methods for phenolic compounds. ► Methods for quantification and separation of polyphenols ...(spectrophotometric methods and chromatographic techniques). ► Spectral methods used in structure elucidation and characterisation of phenolic compounds.
Phenolic compounds, ubiquitous in plants, are of considerable interest and have received more and more attention in recent years due to their bioactive functions. Polyphenols are amongst the most desirable phytochemicals due to their antioxidant activity. These components are known as secondary plant metabolites and possess also antimicrobial, antiviral and anti-inflammatory properties along with their high antioxidant capacity. Many efforts have been made to provide a highly sensitive and selective analytical method for the determination and characterisation of polyphenols. The aim of this paper is to provide information on the most recent developments in the chemical investigation of polyphenols emphasising the extraction, separation and analysis of these compounds by chromatographic and spectral techniques.
Recently, emerging studies on the relationship between insomnia, the most common sleep disorder, and cancer have been published, but with inconsistent results. With the development of society and the ...accelerated pace of life, more and more people experience insomnia. Therefore, it is important to clarify the association. Relevant literature was obtained through a search of seven databases and supplementary searches. After a strict screening, eight cohort studies (seven prospective and one retrospective) involving 578,809 participants and 7,451 cancer events were incorporated into our analysis. The results demonstrate a modest 24% overall increased risk of cancer for individuals with insomnia in comparison to those without insomnia. The sensitivity analysis shows that the correlation between the two is stable. Subgroup analyses show that the risk of developing cancer was significantly higher in studies conducted in women (HR = 1.24; 95% CI, 1.01–1.53), but not in men (HR = 1.28; 95% CI, 0.90–1.80). Similarly, in terms of specific cancer types, the pooled HR was only significantly higher in thyroid cancer (HR = 1.36; 95% CI, 1.12–1.65) and not in other types of cancer (p > 0.05). Our findings suggest that insomnia may serve as an early warning sign of the onset of cancer and provide an opportunity for early detection and early intervention. Our findings should be treated with caution because of the limited number of included studies and potential bias. More additional studies are warranted to provide more information on the carcinogenic effect of insomnia.
Exploitation of the intrinsic electrical properties of particles has recently emerged as an appealing approach for trapping and separating various scaled particles. Initiative particle manipulation ...by dielectrophoresis (DEP) showed remarkable advantages including high speed, ease of handling, high precision and being label-free. Herein, we provide a general overview of the manipulation of polystyrene (PS) beads and related particles
via
DEP; especially, the wide applications of these manipulated PS beads in the quantitative evaluation of device performance for model validation and standardization have been discussed. The motion and polarizability of the PS beads induced by DEP were analyzed and classified into two categories as positive and negative DEP within the time and space domains. The DEP techniques used for bioparticle manipulation were demonstrated, and their applications were conducted in four fields: trapping of single-sized PS beads, separation of multiple-sized PS beads by size, separation of PS beads and non-bioparticles, and separation of PS beads and bioparticles. Finally, future perspectives on DEP-on-a-chip have been proposed to discriminate bio-targets in the network of microfluidic channels.
Exploitation of the intrinsic electrical properties of particles has recently emerged as an appealing approach for trapping and separating various scaled particles.
The efficacy of the antibody drug conjugate (ADC) Trastuzumab deruxtecan (T-DXd) in HER2 low breast cancer patients suggests that the historical/conventional assays for HER2 may need revision for ...optimal patient care. Specifically, the conventional assay is designed to distinguish amplified HER2 from unamplified cases but is not sensitive enough to stratify the lower ranges of HER2 expression. Here we determine the optimal dynamic range for unamplified HER2 detection in breast cancer and then redesign an assay to increase the resolution of the assay to stratify HER2 expression in unamplified cases. We used the AQUA™ method of quantitative immunofluorescence to test a range of antibody concentrations to maximize the sensitivity within the lower range of HER2 expression. Then, using a cell line microarray with HER2 protein measured by mass spectrometry we determined the amount of HER2 protein in units of attomols/mm
. Then by calculation of the limits of detection, quantification, and linearity of this assay we determined that low HER2 range expression in unamplified cell lines is between 2 and 20 attomol/mm
. Finally, application of this assay to a serial collection of 364 breast cancer cases from Yale shows 67% of the population has HER2 expression above the limit of quantification and below the levels seen in HER2 amplified breast cancer. In the future, this assay could be used to determine the levels of HER2 required for response to T-DXd or similar HER2 conjugated ADCs.
•We report a novel SERS-based lateral flow (LF) assay for the sensitive detection of bacterial pathogens.•Quantitative analysis of low-abundance target bacteria is possible using this SERS assay ...platform.•This approach provides new insights into early detection of specific bacterial pathogens in the field.
Bacterial pathogens such as Yersinia pestis, Francisella tularensis, and Bacillus anthracis are classified into the highest rank of potential bioterrorism agents. Colorimetric lateral flow assay (LFA) strips are commercially available but these conventional strips have drawbacks in terms of low sensitivity and limit of quantitative analysis. Therefore, there is an urgent need for a new sensing platform to detect these pathogens in the early contamination stage. In this study, a novel surface-enhanced Raman scattering (SERS)-based LFA strip was developed for sensitive detection of bacterial pathogens. Target-specific SERS nanotags (Raman reporter-labeled gold nanoparticles) were used as an alternative to the gold nanoparticles in conventional LFA strips. Using these SERS nanotags the presence of bacteria could be identified through a simple color change in the test line. Additionally, highly sensitive and accurate quantitative analysis could be performed by monitoring the characteristic Raman peak intensity of SERS nanotags that were captured in the test line. This highly sensitive method required a short assay time (15 min) and a tiny volume of pathogen sample (40 μL). We believe that the proposed SERS-based LFA technique has great potential as a valuable tool in the early detection of specific bacterial pathogens in the field due to its excellent analytical sensitivity.
A single‐molecule electrochemiluminescence bioassay is developed here which allows imaging and direct quantification of single biomolecules. Imaging single biomolecules is realized by localizing the ...electrochemiluminescence events of the labeled molecules. Such an imaging system allows mapping the spatial distribution of biomolecules with electrochemiluminescence and contains quantitative single‐molecule insights. We further quantify biomolecules by spatiotemporally merging the repeated reactions at one molecule site and then counting the clustered molecules. The proposed single‐molecule electrochemiluminescence bioassay is used to detect carcinoembryonic antigen, showing a limit of detection of 67 attomole concentration which is 10 000 times better than conventional electrochemiluminescence bioassays. This spatial resolution and sensitivity enable single‐molecule electrochemiluminescence bioassay a new toolbox for both specific bioimaging and ultrasensitive quantitative analysis.
We developed a single‐molecule electrochemiluminescence bioassay which allows imaging of single biomolecules with nanometer resolution based on localizing the repeated electrochemiluminescence reactions. Quantification of biomolecules is achieved by merging the clustered reactions at one molecule site and then counting the merged molecule numbers.
Augmented reality (AR) is an important technology to enhance learning experiences. Many studies have been conducted to establish the tendencies, affordances and challenges of this technology in ...educational settings. However, these studies have little analyzed important issues such as the special needs of specific users or the impact of AR on education through the quantitative analysis of the data. This paper presents a literature review that covers 61 studies published between 2012 and 2018 in scientific journals and conference proceedings. As a result, it identifies the status and tendencies in the usage of AR in education, the impact of this technology on learning processes, open questions as well as opportunities and challenges for developers and practitioners. The results indicate that AR has a medium effect on learning effectiveness (
d
= .64,
p
< .001). The most reported advantages of AR systems in education are “learning gains” and “motivation.” Otherwise, it is also important to mention that only one of the AR systems of the studies includes
accessibility features
, which represents a setback in terms of social inclusion. Therefore, given the apparent multiple benefits of using AR systems in educational settings, stakeholders have great opportunities to develop new and better systems that benefit all learners. This technology covers a wide range of topics, target groups, academic levels and more. This could be an indicator that AR is achieving maturity and has successfully taken root in educational settings.
Conventional quantitative methods for the measurement of organizational legitimacy consider mainly three sources that make judgments about organizations visible: news media, accreditation bodies, and ...surveys. Over the last decade, however, social media have enabled ordinary citizens to bypass the gatekeeping function of these institutional evaluators and autonomously make individual judgments public. This inclusion of voices beyond functional and formally organized stakeholder groups potentially pluralizes the ongoing discussions about organizations. The individual judgments in blogs, tweets, and Facebook posts give indication about the broader fit between an organization’s perceived behavior and heterogeneous social norms and therefore constitute an indicator of organizational legitimacy that can be accessed and measured. We propose the use of social media data and sentiment analysis to study the affect-based responses to organizational actions by citizens. We critically discuss and compare the method with existing quantitative methods for legitimacy measurement and apply them to a recent case in the banking industry. We discuss the value of the method for studying the process of legitimacy construction as the expression and negotiation of normative judgments about organizations by various evaluators.
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