Heavy metals are well-known environmental pollutants owing to their toxicity, longevity in the atmosphere, and ability to accumulate in the human body via bioaccumulation. The pollution of ...terrestrial and aquatic ecosystems with toxic heavy metals is a major environmental concern that has consequences for public health. Most heavy metals occur naturally, but a few are derived from anthropogenic sources. Heavy metals are characterized by their high atomic mass and toxicity to living organisms. Most heavy metals cause environmental and atmospheric pollution, and may be lethal to humans. Heavy metals can become strongly toxic by mixing with different environmental elements, such as water, soil, and air, and humans and other living organisms can be exposed to them through the food chain. Plenty of experimental studies were performed to appraise the promising treatment options from natural products. Additionally, nanotechnology based treatment options are being constantly developed. As an emerging field, nanotechnology is making substantial advances in the analysis and removal of heavy metals from complicated matrices. Removal of heavy metal has been accomplished by the use of a variety of nanomaterials, including graphene and its derivatives, magnetic nanoparticles, metal oxide nanoparticles, and carbon nanotubes, to name a few. Using nanotechnology for heavy metal analysis and removal from food and water resources provides many benefits over traditional methods. These advantages include a broad linear range, low detection and quantification limits, a high sensitivity, and high selectivity. Therefore this review aimed to explore the environmental consequences of the heavy metals, toxicity to the human health, as well as novel therapeutics development from the natural resources. Additionally, nanotechnological and nanomedicinal applications to treat heavy metal toxicity are also highlighted in this review.
Even though power conversion efficiency has already reached 25.8%, poor stability is one of the major challenges hindering the commercialization of perovskite solar cells (PSCs). Several initiatives, ...such as structural modification and fabrication techniques by numerous ways, have been employed by researchers around the world to achieve the desired level of stability. The goal of this review is to address the recent improvements in PSCs in terms of structural modification and fabrication procedures. Perovskite films are used to provide a broad range of stability and to lose up to 20% of their initial performance. A thorough comprehension of the effect of the fabrication process on the device's stability is considered to be crucial in order to provide the foundation for future attempts. We summarize several commonly used fabrication techniques - spin coating, doctor blade, sequential deposition, hybrid chemical vapor, and alternating layer-by-layer. The evolution of device structure from regular to inverted, HTL free, and ETL including the changes in material utilization from organic to inorganic, as well as the perovskite material are presented in a systematic manner. We also aimed to gain insight into the functioning stability of PSCs, as well as practical information on how to increase their operational longevity through sensible device fabrication and materials processing, to promote PSC commercialization at the end.
Stability issues are the key challenges for commercialization of PSCs. Different stability issues including modification of the structural design and material, fabrication process should be considered and improved to improve the stability of PSCs.
Various atomic and nuclear methods use hard (high-energy) X-rays to detect elements. The current study aims to investigate the hard X-ray production rate via high-energy proton beam irradiation of ...various materials. For which, appropriate conditions for producing X-rays were established. The MCNPX code, based on the Monte Carlo method, was used for simulation. Protons with energies up to 1650 MeV were irradiated on various materials such as carbon, lithium, lead, nickel, salt, and soil, where the resulting X-ray spectra were extracted. The production of X-rays in lead was observed to increase 16 times, with the gain reaching 0.18 as the proton energy increases from 100 MeV to 1650 MeV. Comparatively, salt is a good candidate among the lightweight elements to produce X-rays at a low proton energy of 30 MeV with a production gain of 0.03. Therefore, it is suggested to irradiate the NaCl target with 30 MeV proton to produce X-rays in the 0–2 MeV range.
As a cheap source of high-quality protein, healthy fats and essential nutrients, dried fish is a common item in the daily diet of the Bangladesh populace. In this study, ten types of widely consumed ...dried fish (H. neherius, T. lepturu, P.chinensis, P. affinis, A. mola, P. microdon, I. megaloptera, C. dussumieri, L. calcarifer, and G. chapra) were analyzed for Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Hg, Pb, Ni and As by using an Energy Dispersive X-ray Fluorescence (EDXRF) technique. The concentration of the studied metals was found in the order Fe > Zn > Hg > Cu > Se > Cr > Mn > Co > Rb > Pb, while As and Ni were below the limit of detection. All fish species showed moderate to high pollution, where the species H. Neherius and P. Chinensis are the most and least polluted ones, respectively. The probable source of contamination is the leaching from the drying pans into the fish samples, atmospheric deposition, anthropogenic contamination, etc. of the water body where these fish were harvested. The calculated hazard index for the general population was below the maximum limiting value (i.e., < 1) except for Hg to children. The carcinogenic risk showed values lower than the acceptable limit for cancer risks (10
to 10
). Periodic monitoring of trace metals in the aquatic organisms along with fish is recommended to avoid any unexpected health hazards caused by the toxic heavy metals via fish consumption.
Microplastics (MP) were recognized as an emergent pollution problem due to their ubiquitous nature and bioaccumulative potential. Those present in salt for consumption could represent a human ...exposure route through dietary uptake. The current study, conducted in Bangladesh, reports microplastics contamination in coarse salt prepared for human consumption. Sea salt samples were collected from eight representative salt pans located in the country's largest salt farming area, in the Maheshkhali Channel, along the Bay of Bengal. Microplastics were detected in all samples, with mean concentrations ranging from 78 ± 9.33 to 137 ± 21.70 particles kg
, mostly white and ranging in size from 500-1000 µm. The prevalent types were: fragments (48%) > films (22%) > fibers (15%) > granules and lines (both 9%). Fourier transform mid-IR and near-IR spectra (FT-MIR-NIR) analysis registered terephthalate (48%), polypropylene (20%), polyethylene (17%), and polystyrene (15%) in all samples. These results contribute to the MP's pollution knowledge in sea salts to understand and reduce this significant human exposure route and environmental pollution source in the future.
In terms of cost-efficiency, biocompatibility, environmental friendliness, and scalability, green nanoparticle (NP) synthesis is a novel field of nanotechnology that outperforms both physical and ...chemical approaches. Plants, bacteria, fungi, and algae have lately been used to produce metals and metal oxide nanoparticles as an alternate method. The development of alternative strategies to restrict the growth of hazardous bacteria, as well as the building of resistance by germs to various antibiotics, led to the introduction of nanoparticles as novel antimicrobial agents. Metal oxides have been found to form oxide monolayer structures for drug delivery when they react with a transporter's surface. Metal oxide nanoparticles have emerged as biomedical materials in recent years, with applications in immunotherapy, tissue treatment, diagnostics, regenerative medicine, wound healing, dentistry, and biosensing platforms. Biotoxicology and its antimicrobial, antifungal, and antiviral characteristics were hotly contested. Metal oxide nanoparticles have tremendous applicability and commercial value, as evidenced by important discoveries in the realm of nanobiomedicine in terms of locations and amounts. This paper describes the production of nanometal oxides from various green materials, as well as their applications.
Abstract
Nuclear radiation shielding capabilities for a glass series 20Bi
2
O
3
− xPbO − (80 − 2x)B
2
O
3
− xGeO
2
(where x = 5, 10, 20, and 30 mol%) have been investigated using the Phy-X/PSD ...software and Monte Carlo N-Particle transport code. The mass attenuation coefficients (μ
m
) of selected samples have been estimated through XCOM dependent Phy-X/PSD program and MCNP-5 code in the photon-energy range 0.015–15 MeV. So obtained μ
m
values are used to calculate other γ-ray shielding parameters such as half-value layer (HVL), mean-free-path (MFP), etc. The calculated μ
m
values were found to be 71.20 cm
2
/g, 76.03 cm
2
/g, 84.24 cm
2
/g, and 90.94 cm
2
/g for four glasses S
1
to S
4
, respectively. The effective atomic number (Z
eff
)values vary between 69.87 and 17.11 for S
1
or 75.66 and 29.11 for S
4
over 0.05–15 MeV of photon-energy. Sample S4, which has a larger PbO/GeO
2
of 30 mol% in the bismuth-borate glass, possesses the lowest MFP and HVL, providing higher radiation protection efficiency compared to all other combinations. It shows outperformance while compared the calculated parameters (HVL and MFP) with the commercial shielding glasses, different alloys, polymers, standard shielding concretes, and ceramics. Geometric Progression (G-P) was applied for evaluating the energy absorption and exposure buildup factors at energies 0.015–15 MeV with penetration depths up to 40 mfp. The buildup factors showed dependence on the MFP and photon-energy as well. The studied samples' neutron shielding behavior was also evaluated by calculating the fast neutron removal cross-section (Σ
R
), i.e. found to be 0.139 cm
−1
for S
1
, 0.133 cm
−1
for S
2
, 0.128 cm
−1
for S
3,
and 0.12 cm
−1
for S
4
. The results reveal a great potential for using a glass composite sample S4 in radiation protection applications.
A viable hydrothermal technique has been explored for the synthesis of copper doped Zinc oxide nanoparticles (Cu-doped ZnO-NPs) based on the precursor's mixture of Copper-II chloride dihydrate ...(CuCl2.2H2O), Zinc chloride (ZnCl2), and potassium hydroxide (KOH). X-ray diffraction (XRD) reported the hexagonal wurtzite structure of the synthesized Cu-doped ZnO-NPs. The surface morphology is checked via field emission scanning electron microscopy (FE-SEM), whereas, the elemental compositions of the samples were confirmed by Raman, and X-ray photoelectron spectroscopy (XPS), respectively. The as-obtained ZnO-NPs and Cu-doped ZnO-NPs were then tested for their antibacterial activity against clinical isolates of Gram-positive (Staphylococcus aureus, Streptococcus pyogenes) and Gram-negative (Escherichia coli, Klebsiella pneumonia) bacteria via agar well diffusion method. The zone of inhibition (ZOI) for Cu-doped ZnO-NPs was found to be 24 and 19 mm against S. Aureus and S. pyogenes, and 18 and 11 mm against E. coli and K. pneumoniae, respectively. The synthesized Cu-doped ZnO-NPs can thus be found as a potential nano antibiotic against Gram-positive multi-drug resistant bacterial strains.
Electron cyclotron resonance heating method of Particle-in-Cell code was used to analyze heating phenomena, axial kinetic energy, and self-consistent electric field of confined electron plasma in ...ELTRAP device by hydrogen and helium background gases. The electromagnetic simulations were performed at a constant power of 3.8 V for different RF drives (0.5 GHz- 8 GHz), as well as for 1 GHz constant frequency at these varying amplitudes (1 V-3.8 V). The impacts of axial and radial temperatures were found maximum at 1.8 V and 5 GHz as compared to other amplitudes and frequencies for both background gases. These effects are higher at varying radio frequencies due to more ionization and secondary electrons production and maximum recorded radial temperature for hydrogen background gas was 170.41 eV. The axial kinetic energy impacts were found more effective in the outer radial part (between 0.03 and 0.04 meters) of the ELTRAP device due to applied VRF through C8 electrode. The self-consistent electric field was found higher for helium background gas at 5 GHz RF than other amplitudes and radio frequencies. The excitation and ionization rates were found to be higher along the radial direction (r-axis) than the axial direction (z-axis) in helium background gas as compared to hydrogen background gas. The current studies are advantageous for nuclear physics applications, beam physics, microelectronics, coherent radiation devices and also in magnetrons.
•Deuteron-induced nuclear reactions on natural erbium were studied.•Stacked-foil activation technique and γ-ray spectroscopy was used.•Production parameters of 167mTm in NCA form is ...optimized.•Measured (d,p) data is important to improve the predicting capability of model codes.
Excitation functions for the natEr(d,x)163,165,166,167,168,170Tm and natEr(d,x)171Er nuclear reactions were measured from the respective thresholds up to 24 MeV by using a stacked-foil activation technique combined with HPGe γ-ray spectrometry. Measured data show a partial agreement when compared with the available literature data, theoretical data extracted from the TENDL-2019 library, and predicted data by the model code EMPIRE-3.2.2. Estimated physical thick target yields of the reaction products show close values to the directly measured ones available in the literature. The deduced yield curves indicate that a typical irradiation (Ed = 15 MeV, Id = 100 µA, tirr = 72 h) of enriched 167Er target by a low energy deuteron cyclotron is suitable to obtain more than a hundred GBq activity of 167Tm with negligible impurity from 168Tm. Measured data of 170Er(d,p)171Er reaction have great significance to improve the predicting capability of the model code.