Carbon nanotubes (CNTs) are widely used in industry, but their environmental impacts on soil microbial communities are poorly known. In this paper, we compare the effect of both raw and acid treated ...or functionalized (fCNTs) multi-walled carbon nanotubes (MWCNTs) on soil bacterial communities, applying different concentrations of MWCNTs (0 µg/g, 50 µg/g, 500 µg/g and 5000 µg/g) to a soil microcosm system. Soil DNA was extracted at 0, 2 and 8 weeks and the V3 region of the 16S rRNA gene was PCR-amplified and sequenced using paired-end Illumina bar-coded sequencing. The results show that bacterial diversity was not affected by either type of MWCNT. However, overall soil bacterial community composition, as illustrated by NMDS, was affected only by fMWCNT at high concentrations. This effect, detectable at 2 weeks, remained equally strong by 8 weeks. In the case of fMWCNTs, overall changes in relative abundance of the dominant phyla were also found. The stronger effect of fMWCNTs could be explained by their intrinsically acidic nature, as the soil pH was lower at higher concentrations of fMWCNTs. Overall, this study suggests that fMWCNTs may at least temporarily alter microbial community composition on the timescale of at least weeks to months. It appears, by contrast, that raw MWCNTs do not affect soil microbial community composition.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
There is considerable interest in the factors which may explain variation in microbial community assembly processes. In this study, we investigated bacterial community assembly, phylogenetic ...diversity and the relative role of deterministic and stochastic processes along environmental gradients on Mt. Norikura, Japan. DNA extracted from soil samples collected at a range of elevations was PCR-amplified targeting the V3 and V4 regions of the bacterial 16S rRNA gene, and sequenced using Illumina MiSeq. We hypothesized that elevation would be a strong predictor of phylogenetic community assembly, with communities being more phylogenetically clustered towards higher elevations, due to more extreme physiological conditions. We also hypothesized a greater role of stochasticity at the highest elevations, due to more frequent soil disturbance. Contrary to our hypotheses, we found that the strength of phylogenetic clustering and the role of stochasticity were strongly related to soil pH, with phylogenetic clustering and deterministic processes being strongest at lower soil pH values. Moreover, there was no trend towards stronger influence of phylogenetic clustering and stochasticity in the upper elevations of Mt. Norikura. These results reveal an overwhelming influence of soil pH on phylogenetic community assembly of soil bacteria, even when a range of other environmental gradients are present.
Understanding the nature of interactions of targeted drug‐delivery vehicles, such as functionalized carbon nanotubes (f‐CNTs) and their composites, with a cell or its organelles or DNA, where water ...is a major constituent, requires molecular‐level understanding of f‐CNTs with analogous chemical systems. The nature of interaction has not yet been explored within the scope of formation of giant aggregates by self‐assembly processes. Crystals of platinum(II) dithiolene Pt(mnt)2PPh42 (1) and gadolinium(III) dithiolene Gd(mnt)3PPh43 (2) (mnt=maleonitrile dithiolate) form nanospheres (diameter 88 nm) and nanoflowers (400–600 nm) in acetonitrile/water and DMF/water solvent mixtures, respectively. The formation of nanospheres or nanoflowers is proposed to be a water‐induced phenomenon. These nanospheres and nanoflowers interact with f‐CNTs by forming either spherical supramolecular assemblies (3, diameter up to 45. 5 μm) in the case of platinum(II) dithiolene or composite flowers (4) with CNT buckling for gadolinium(III) dithiolene. Both nanostructures, (3) and (4), show emission upon excitation at a range of wavelengths (λex=385–560 nm). The fluorescence emissions of the composite materials 3 and 4 are proposed to be due to separation of energy states of the nanospheres of 1 or the nanoflowers of 2 by the energy states of the f‐CNTs, leading to the possibility of new electronic transitions.
Bioimaging model: Gadolinium(III) and platinum(II) dithiolenes display water‐induced formation of nanoflowers and nanospheres, which further form carbon nanotube (CNT)‐based composite flowers and spheres. These CNT‐based composite materials display a high‐intensity photoluminescence in the visible region that is reminiscent of cellular bioimaging.
Microbial communities commonly consist of a large number of rare taxa (RT) and few abundant taxa (AT), and it is important to identify the differences of the community assembly processes between RT ...and AT in response to environmental changes. However, the community assembly processes governing AT and RT in coastal wetland soils along an inundation gradient remain elusive. Here, an
mesocosm, with continuous inundation gradients and native mangrove
or exotic cordgrass
, was established to determine the patterns and driving factors of community turnover and assembly processes of AT and RT. We found that RT exhibited a remarkably lower turnover rate than AT, and the niche breadth of RT was significantly narrower than that of AT. In comparison with AT, RT presented stronger phylogenetic signals for ecological preferences across environmental gradients. Null model analyses revealed that RT were more phylogenetically clustered and primarily governed by homogeneous selection, while AT were more overdispersed and dominated by dispersal limitation. Soil water content was the most decisive factor for community turnover and assembly processes of both AT and RT. Structural equation modeling analysis showed that RT were strongly associated with
biomass rather than
biomass, suggesting a strong relationship between RT and the growth of mangrove
Overall, our study revealed distinct assembly processes of soil AT and RT communities in coastal wetlands, which is crucial for mechanistic understanding of the establishment and maintenance of soil microbial diversity in coastal wetlands under conditions of global environmental changes.
Coastal wetlands are one of the important ecosystems that play a crucial role in the regulation of climate change. Rare taxa (RT) exist in one habitat along with abundant taxa (AT). In this study, we found that RT exhibited narrower niche breadth and stronger phylogenetic signals than AT. Null model analyses showed that RT were more phylogenetically clustered and primarily governed by homogeneous selection, while AT were more overdispersed and dominated by dispersal limitation. Revealing the differences in the community assembly processes between AT and RT in coastal wetlands is critical to understand the establishment and maintenance of soil microbial diversity in coastal wetlands with regard to environmental changes.
Dual-phase xenon detectors lead the search for keV-scale nuclear recoil signals expected from the scattering of weakly interacting massive particle (WIMP) dark matter, and can potentially be used to ...study the coherent nuclear scattering of MeV-scale neutrinos. New capabilities of such experiments can be enabled by extending their nuclear recoil searches down to the lowest measurable energy. The response of the liquid xenon target medium to nuclear recoils, however, is not well characterized below a few keV, leading to large uncertainties in projected sensitivities. In this work, we report a new measurement of ionization signals from nuclear recoils in liquid xenon down to the lowest energy reported to date. At 0.3 keV, we find that the average recoil produces approximately one ionization electron; this is the first measurement of nuclear recoil signals at the single-ionization-electron level, approaching the physical limit of liquid xenon ionization detectors. We discuss the implications of these measurements on the physics reach of xenon detectors for nuclear-recoil-based WIMP dark matter searches and the detection of coherent elastic neutrino-nucleus scattering.
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•A long-chain trifunctional amine was used to introduce crosslinking in polyurea.•Dynamic Mechanical Analysis was used to quantify crosslinking density in polyurea.•Optimal amount of ...crosslinking led to improved mechanical properties.•Chemical resistance improved with increasing extent of crosslinking.
Among the many desirable properties of polymeric coatings, the most important include ease of application, rapid cure time, adhesive properties and excellent mechanical properties. In this context, spray coated polyureas are finding increasing applications in niche areas that otherwise pose considerable challenge to the traditional coating chemistries. In this work, we demonstrate the effect of introducing chemical cross-linking on the mechanical, thermal and structural properties of spray coated polyurea. A long chain trifunctional amine was introduced as a co-reactant in the resin blend, the amount of crosslinker being varied from 0 to 3.5 mol % (crosslinking density 28–180 mol/m3, affine network model). The mechanical properties of spray coated polyurea films, both in quasi-static as well as dynamic conditions were determined. Physically crosslinked polyurea coatings (in the absence of chemical cross-linking) exhibited tensile strength ∼ 7.4 ± 0.7 MPa and elongation of 121 ± 3.7%. Introduction of long chain amine led to an improvement in these characteristic properties till maxima at 2.2 mol%, subsequent to which both strength and elongation decreased. Chemical cross-linking led to restraining of the segmental motions reflecting in terms of increased glass transition temperature, as evidenced by dynamic mechanical analysis and differential scanning calorimetry. The chemical resistance of polyurea also improved substantially due to crosslinking, which reflected in terms of decreased swelling ratio in different organic media.
Rainfall and runoff are important characteristics that determine the water sources for harvesting and recharging the watershed. This study focused on estimating the AHP-based runoff potential zones ...and spatial distribution of surface runoff of the Mand catchment as it had undergone major landuse changes and deforestation due to extensive mining. The catchment was divided into 13 sub-watersheds (WS) to account for geographical heterogeneity. The spatial distribution of surface runoff was estimated by using the SCS-CN technique in a geographic information system (GIS) environment. The input data layers, such as land use/land cover map, soil map, rainfall map, and antecedent moisture content (AMC) maps, were generated in the ArcGIS domain for the growing season (June–October) of 2019. The long-term runoff potential zone was defined utilising nine influencing elements and the average annual rainfall of five years (2015–2019) in the MCDA-AHP weighted overlay technique. The result of MCDA-AHP weighted overlay shows WS-7 and WS-11 are the highest runoff potential zone within the catchment. The runoff estimated by the SCS-CN method was found to be 5070.00 Mm
3
in the year 2019 in the study area. Amongst the all sub-watersheds (WS), the southeastern section, i.e., WS-7 and WS-11, yielded total runoff of 534.75 and 772.15 Mm
3
, respectively. The monthly highest runoff was obtained during the month of August in WS-7 and WS-11 as 468.06 and 441.91 Mm
3
, respectively, and were also found to be the highest runoff potential zones. Findings from both methods indicate that the watershed had the same area as both high runoff potential zones and high estimated runoff. Based on the estimated runoff and runoff potential zones, water conservation structures have been proposed for the WS-7 and WS-11. This methodology can be successfully employed as a better approach for identifying site selection of water conservation structures as it requires less time and capacity to handle big datasets. This finding and methodology employed can be widely used in similar river catchments around the world for identifying the runoff potential zones and development of water conservation plans.
In this study biosorption potential of pre-treated arca shell biomass for lead, copper, nickel, cobalt and cesium was explored from the artificially prepared solution containing known amount of ...metals. The effects of pH, initial concentration, biosorbent dosage and contact time were studied in batch experiments. Effects of common ions like sodium, potassium, calcium and magnesium on the sorption capacity of pre-treated arca biomasses were also studied. To analyse the homogeneity of the biomaterial, experiments were performed for eight lots arca shell biomass for all the studies elements and it was observed that relative standard deviation in uptake capacity was within 10% for all elements. At equilibrium, the maximum total uptake by shell biomaterial was 18.33
±
0.44, 17.64
±
0.31, 9.86
±
0.17, 3.93
±
0.11 and 7.82
±
0.36
mg/g for lead, copper, nickel, cesium and cobalt, respectively, under the optimised condition of pH, initial concentration, biosorbent dose and contact time. Effect of all the common ions jointly up to concentration of 50
ppm was negligible for all the elements but at higher levels the cations affects the uptake capacity. Sorption isotherms were studied to explain the removal mechanism of both elements by fitting isotherms data into Lagergren, Freundlich and Langmuir equations. Halls separation factor estimated under optimised condition also favours the sorption potential of these elements using arca shell biomass. Arca shell biomass can be effectively and efficiently employed for removal of studied elements after optimisation of parameters.
The changes in land use and land cover (LULC) are one of the primary forces for the worldwide climate, ecosystem, and environmental changes. A detail understanding of the dynamics of LULC changes is ...requisite for natural resource management and sustainable development. The present study region is the Mand catchment situated in Chhattisgarh, which has witnessed changes in LULC due to a rise in anthropogenic activities, such as an increase in population, urbanization, mining activity, and agriculture, as well as natural causes, such as climate change. The present study focused on spatiotemporal LULC change analysis and the subsequent prediction of future LULC patterns. A supervised image classification method in Geographic Information System (GIS) was used to analyze decadal LULC changes from 2001 to 2021. The Cellular Automata–Artificial Neural Network (CA–ANN) model, incorporated in the MOLUSCE (Modules of Land Use Change Evaluation) plugin of QGIS, was used for the future prediction of LULC from 2030 to 2040. The overall accuracy of LULC for 2001, 2010, and 2021 was obtained as 82, 86, and 90%, respectively, and the overall kappa coefficient was obtained as 0.79, 0.84, and 0.88, respectively. The decadal study of LULC change concludes that the agricultural land counts highest area of 29.21% as compared to other LULCs in 2001 which was further increased 31.76% in 2021. Increasing trend were also noticed for the open forest, shallow waterbody, fallow land, and settlement for the decadal years 2001 to 2021 by 1.7, 7.41, 7.57, and 2.55%, respectively. A decreasing trend was observed in LULC changes during the decadal years 2001 to 2021 for dense forest, deep water body, and barren land by 10.28, 0.66, and 10.24%, respectively. The LULC predictions for 2030 and 2040 indicate a similar trend to the prior years, with an increase in settlement, fallow land, agricultural land, open forests, shallow waterbodies, scrubland, and a decrease in dense forests, deep waterbodies, and barren land. This comprehensive analysis of the changes in LULC over an extended period will prove to be a valuable resource for policymakers and planners seeking to achieve sustainable development and effective management of the ecosystem within the study area.
This paper presents a technology computer-aided design analysis of an ultrasensitive black phosphorus junctionless recessed channel MOSFET as a biosensor. A nano cavity gap is embedded in the gate ...insulator region (for molecules immobilization) due to which gate capacitance changes owing to the accumulation of different molecules which reflects the deviation in threshold voltage. Higher sensitivity (1.7) is achieved for protein at low V
ds
(0.2 V) in comparison to streptavidin (1.17) and Biotin (1.24). Further, the effect of cavity gap length and oxide thickness variation is also examined. All the results pave the way for early detection techniques of protein-related diseases such as Alzheimer’s diseases, ovarian cancer and coronary artery disease with the existing complementary metal–oxide–semiconductor technology.
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