The concerns related to particulate matter's health effects alongside the increasing demands from citizens for more participatory, timely, and diffused air quality monitoring actions have resulted in ...increasing scientific and industrial interest in low-cost particulate matter sensors (LCPMS). In the present paper, we discuss 50 LCPMS models, a number that is particularly meaningful when compared to the much smaller number of models described in other recent reviews on the same topic. After illustrating the basic definitions related to particulate matter (PM) and its measurements according to international regulations, the device's operating principle is presented, focusing on a discussion of the several characterization methodologies proposed by various research groups, both in the lab and in the field, along with their possible limitations. We present an extensive review of the LCPMS currently available on the market, their electronic characteristics, and their applications in published literature and from specific tests. Most of the reviewed LCPMS can accurately monitor PM changes in the environment and exhibit good performances with accuracy that, in some conditions, can reach
values up to 0.99. However, such results strongly depend on whether the device is calibrated or not (using a reference method) in the operative environment; if not,
values lower than 0.5 are observed.
•Sea urchins revealed very sensitive organisms to nZnO.•nZnO toxicity for P.lividus could not be ascribable only to the ionic Zn.•Sperm fertilization capability is not affected from tested Zn ...compounds.•nZnO dispersed in ASW aggregate in μm size as function of particle concentration.•Sea urchin developmental anomalies mainly evidenced nZnO toxicity.
The effect of nano ZnO (nZnO) upon the fertilization and early development of embryos of the Mediterranean sea urchin Paracentrotus lividus is reported herein for the first time. Zn ion (ZnCl2) and bulk ZnO (bZnO) toxicity were assessed for comparison. The embryotoxicity tests showed a 100% effect already at 1μM of nZnO (expressed as Zn) while bZnO and ZnCl2 showed EC50s of 0.98 0.88–1.19μM Zn and 2.02 1.97–2.09μM Zn, respectively. Noteworthy, the frequency of developmental defects for the three compounds was dissimilar and a specific trend for larval skeletal abnormality produced by nZnO was observed.
The sperm fertilization capability was only slightly affected by the tested chemicals while the effects were dramatic on the offspring quality of sperms exposed to ZnO compounds resulting in an early block of the regular larval development.
ZnO toxicity seems related not only to Zinc ions but also to some surface interactions of particle/aggregates with target organisms and/or with the seawater.
The aim of this work is to investigate the degradation of perovskite solar cells (PSCs) by means of impedance spectroscopy, a highly sensitive characterization technique used to establish the ...electrical response of a device in a nondestructive manner. In this paper, PSCs with two different electron transport layers (ETLs) are studied: PSCs with undoped SnO2 as an ETL are compared to PSCs with an ETL composed of graphene-doped SnO2 (G-SnO2). Experimental data were collected immediately after fabrication and after one week, monitoring both impedance spectroscopy and dark current-voltage (I-V) curves. It was observed that, in the case of the undoped PSCs, the degradation of the solar cells affected both the AC behavior of the devices, modifying the associated Nyquist plots, and the DC behavior, observable from the dark I-V measurements. Conversely, the solar cells with G-SnO2 showed no variation. Considering the Nyquist plots, a quantitative analysis was performed by comparing the parameters of a proper equivalent circuit model. The results were coherent with those achieved in the DC analysis, thus proving that the analysis of impedance spectra, supported with dark I-V curves, allows one to gain a deeper knowledge of the degradation phenomena of perovskite solar cells. This study opens the door for further improvement of these devices through a better understanding of their electrical behavior.
The low-power sensing platform proposed by the Convergence project is foreseen as a wireless, low-power and multifunctional wearable system empowered by energy-efficient technologies. This will allow ...meeting the strict demands of life-style and healthcare applications in terms of autonomy for quasi-continuous collection of data for early-detection strategies. The system is compatible with different kinds of sensors, able to monitor not only health indicators of individual person (physical activity, core body temperature and biomarkers) but also the environment with chemical composition of the ambient air (NO
, CO
, NH
particles) returning meaningful information on his/her exposure to dangerous (safety) or pollutant agents. In this article, we introduce the specifications and the design of the low-power sensing platform and the different sensors developed in the project, with a particular focus on pollutant sensing capabilities and specifically on NO
sensor based on graphene and CO sensor based on polyaniline ink.
Introduction
Nanomaterials have widespread applications in several industrial sectors. ZnO nanoparticles (NPs) are among the most commonly used metal oxide NPs in personal care products, coating and ...paints. However, their potential toxicological impact on the environment is largely unexplored.
Materials and methods
The aim of this work was to evaluate whether ZnO nanoparticles exert toxic and genotoxic effects upon terrestrial organisms: plants (
Lepidium sativum
,
Vicia faba)
, crustaceans (
Heterocyipris incongruens
), insects (
Folsomia candida
). To achieve this purpose, organisms pertaining to different trophic levels of the soil ecosystem have been exposed to ZnO NPs. In parallel, the selected soil organisms have been exposed to the same amount of Zn in its ionic form (Zn
2+
) and the effects have been compared.
Results
The most conspicuous effect, among the test battery organisms, was obtained with the ostracod
H. incongruens
, which was observed to be the most sensitive organism to ZnO NPs. The root elongation of
L. sativum
was also mainly affected by exposure to ZnO NPs with respect to ZnCl
2
, while collembolan reproduction test produced similar results for both Zn compounds. Slight genotoxic effects with
V. faba
micronucleus test were observed with both soils.
Conclusion
Nanostructured ZnO seems to exert a higher toxic effect in insoluble form towards different terrestrial organisms with respect to similar amounts of zinc in ionic form.
Characterizing the electron transport layer (ETL)/perovskite interface in perovskite solar cells (PSCs) is of paramount importance for their overall performance. In this article the effect of ...different concentrations of graphene nanoplatelets in addition to SnO 2 is investigated by considering degradation over time. PSCs behavior is monitored by collecting dark current-voltage curves as fabricated and after two months. A deeper insight is gained through impedance spectroscopy analysis. From Nyquist plots equivalent circuit models and the corresponding time constants are extracted. Moreover, resistive part of the impedance associated with high frequency has been related to static shunt resistance, assessing one of the considered ETL doping concentration as the more suitable choice to reduce degradation.
Dose response curve and population growth rate alterations of marine Chlorophyte Dunaliella tertiolecta derived from the exposure to ZnO nanoparticles were evaluated. Bulk ZnO and ionic zinc were ...also investigated for comparison. At the same time, the aggregation state and particle size distribution were monitored. The evaluated 50% effect concentration (EC50 1.94 0.78–2.31mgZnL−1) indicates that nano ZnO is more toxic than its bulk counterpart (EC50 3.57 2.77–4.80mgZnL−1). Cross-referencing the toxicity parameters calculated for ZnCl2 (EC50 0.65 0.36–0.70mgZnL−1) and the dissolution properties of the ZnO, it can be gathered that the higher toxicity of nano ZnO is most likely related to the peculiar physicochemical properties of the nanostate with respect to the bulk material. Furthermore growth rate of D. tertiolecta was significantly affected by nano ZnO exposure.
Our findings suggest that the primary particle size of the dispersed particles affect the overall toxicity.
► nano ZnO is more toxic for the marine alga D. tertiolecta than its bulk counterpart. ► nano ZnO affects the algal growth rate starting from lower tested concentrations. ► Toxic effects of nano ZnO cannot be explained only by the free zinc ion action. ► The nano ZnO primary size affects the overall toxicity.
The sp
carbon-based allotropes have been extensively exploited for the realization of gas sensors in the recent years because of their high conductivity and large specific surface area. A study on ...graphene that was synthetized by means of a novel transfer-free fabrication approach and is employed as sensing material is herein presented. Multilayer graphene was deposited by chemical vapour deposition (CVD) mediated by CMOS-compatible Mo. The utilized technique takes advantage of the absence of damage or contamination of the synthesized graphene, because there is no need for the transfer onto a substrate. Moreover, a proper pre-patterning of the Mo catalyst allows one to obtain graphene films with different shapes and dimensions. The sensing properties of the material have been investigated by exposing the devices to NO
, NH
and CO, which have been selected because they are well-known hazardous substances. The concentration ranges have been chosen according to the conventional monitoring of these gases. The measurements have been carried out in humid N
environment, setting the flow rate at 500 sccm, the temperature at 25 °C and the relative humidity (RH) at 50%. An increase of the conductance response has been recorded upon exposure towards NO
, whereas a decrease of the signal has been detected towards NH
. The material appears totally insensitive towards CO. Finally, the sensing selectivity has been proven by evaluating and comparing the degree of adsorption and the interaction energies for NO
and NH
on graphene. The direct-growth approach for the synthesis of graphene opens a promising path towards diverse applicative scenarios, including the straightforward integration in electronic devices.
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