Green-route synthesis and ab-initio studies of a highly efficient nano photocatalyst:Ce/zinc-oxide nanopetals.

In the present work, Zinc-oxide nanostructures and Ce/Zinc-oxide nanopetals were synthesized by a new environmentally friendly green synthesis method using the Withania coagulans plant. Cerium nitrate Ce(NO3)3 and zinc nitrate Zn(NO3)2 were used as precursors. The prepared nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet spectroscopy (UV-vis). Crystal planes (100), (002), (101), (102), (110), (103), (200), (112) and (201) at 2θ 31.75°, 34.35°, 36.2°, 47.55°, 56.6°, 62.75°, 66.3°, 67.9°, and 69.09° respectively confirmed the hexagonal wurtzite crystal structure of Zinc-oxide. Angular shifts for Ce1% doped Zinc-oxide and Ce3% doped Zinc-oxide nanopetal nanostructures were observed in the (100) and (101) planes of the crystal. More specifically, using Scherrer's equation, the crystallite sizes of Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals were 16.48 ± 02 nm, 17.8 ± 2 nm, 18.8 ± 2 nm, and 18.87 ± 2 nm, respectively. The pure Zinc-oxide grain had the appearance of a nanoflower. On the other hand, the nanopetal structure of Ce5% doped Zinc-oxide nanopetals had oval-shaped nanopetal morphology. The absorption peaks were observed at 373, 376.4, 377, and 378 nm for Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals, respectively, which results in a progressive redshift. The gap energies of Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals were 2.796, 2.645, 2.534, and 2.448 eV, respectively. Photodegradation under visible light (>400 nm) indicates the high efficiency of the photocatalyst based on Ce5% doped Zinc-oxide nanopetals. DFT calculations, structural changes, charge analysis, and electronic band structures were carried out to confirm the experiment.

JRODOS customization for Pakistan and assessment of the consequences of a hypothetical nuclear accident.

Since the Chernobyl disaster in 1986, decision support systems and modelling tools have been utilized in response to nuclear and radiological emergencies. The java-based real-time online decision support system (JRODOS) is a decision support tool that can be utilised in response to an emergency in managing off-site radiological consequences. This article documents the customization and use of JRODOS for Pakistan. JRODOS was tailored to the local Pakistan conditions, and a case study of a theoretical nuclear power plant accident was used to assess JRODOS's feasibility as a decision support tool. A worst-case probabilistic accident scenario was used to identify zones and areas where urgent protective actions, early protective actions and food restriction and other response actions could be required. The areas and distances identified for the implementation of protective and response actions for such a hypothetical accident were found to be in agreement with the emergency planning zones and distances suggested by the International Atomic Energy Agency (IAEA). Additionally, the implications of meteorological and source term input parameters on predicting the radiation doses to members of the public were investigated. It was identified that the output of such tools strongly depends on the availability and accuracy of the input parameters, such as radioactive release and meteorological data. Limitations and uncertainties associated with these tools need to be considered in deciding on protective and other response actions in response to a nuclear accident. As established by the IAEA, protective and other response actions need to be applied on a graded approach, taking into account the protection strategy and uncertainties and limitations in the available information and criteria, based on the conditions at the facility and off-site.

First-Principles Insight into a B4C3 Monolayer as a Promising Biosensor for Exhaled Breath Analysis.

Nanomaterial-based room temperature gas sensors are used as a screening tool for diagnosing various diseases through breath analysis. The stable planar structure of boron carbide (B4C3) is utilized as a base material for adsorption of human breath exhaled VOCs, namely formaldehyde, methanol, acetone, toluene along, with interfering gases of carbon dioxide and water. The adsorption energy, charge density, density of states, energy band gap variation, recovery time, sensitivity, and work function of adsorbed molecules on pristine B4C3 are analyzed by density functional theory. The computed adsorption energies of VOC are in the range of - 0.176 to - 0.238 eV, and a larger interaction distance validate the physisorption behavior of these VOCs biomarkers on pristine boron carbide monolayer. Minute changes are determined from the electronic band structure of all adsorbed systems conserving the semiconducting nature of the B4C3 monolayer. The band gap variation upon adsorption of VOCs and interfering gases is examined between 0.05 and 0.52%. The 13.63 × 10-9 s recovery time of methanol is slower among VOCs, and 0.556 × 10-9 s of carbon dioxide (CO2) is faster for desorption. The results reveal that boron carbide can be utilized as a biosensor at room temperature for the analysis of exhaled VOCs from human breath.

COVID-19 persuaded lockdown impact on local environmental restoration in Pakistan.

Coronavirus disease 2019 (COVID-19) pandemic adversely affected human beings. The novel coronavirus has claimed millions of lives all over the globe. Most countries around the world, including Pakistan, restricted people's social activities and ordered strict lockdowns throughout the country, to control the fatality of the novel coronavirus. The persuaded lockdown impact on the local environment was estimated. In the present study, we assessed air quality changes in four cities of Pakistan, namely Islamabad, Karachi, Lahore, and Peshawar, based on particulate matter (PM2.5), using "Temtop Airing 1000," which is capable of detecting and quantifying PM2.5. The Air Quality Index (AQI) was evaluated in three specific time spans: the COVID-19 pandemic pre- and post-lockdown period (January 1, 2020 to March 20, 2020, and May 16, 2020 to June 30, 2020 respectively), and the COVID-19 pandemic period (March 21 2020 to May 15, 2020). We compared land-monitored AQI levels for the above three periods of time. For validation, air quality was navigated by the Moderate Resolution Imaging Spectrometer (MODIS) satellite during the first semester (January 1 to June 30) of 2019 and 2020. It is seen that the concentration of PM2.5 was considerably reduced in 2020 (more than 50%), ranging from ~ 0.05 to 0.3 kg⋅m3, compared to the same period in 2019. The results revealed that the AQI was considerably reduced during the lockdown period. This finding is a very promising as the inhabitants of the planet Earth can be guaranteed the possibility of a green environment in the future.

Evaluation of adverse effects of particulate matter on human life.

Particulate matter (PM2.5) has a severe impact on human health. The concentration of PM2.5, related to air-quality changes, may be associated with perceptible effects on people's health. In this study, computer intelligence was used to assess the negative effects of PM2.5. The input data, used for the evaluation, were grid definitions (shape-file), PM2.5, air-quality data, incidence/prevalence rates, a population dataset, and the (Krewski) health-impact function. This paper presents a local (Pakistan) health-impact assessment of PM2.5 in order to estimate the long-term effects on mortality. A rollback-to-a-standard scenario was based on the PM2.5 concentration of 15 µg m-3. Health benefits for a population of about 73 million people were calculated. The results showed that the estimated avoidable mortality, linked to ischemic heart disease and lung cancer, was 2,773 for every 100,000 people, which accounts for 2,024,290 preventable deaths of the total population. The total cost, related to the above mortality, was estimated to be US $ 1,000 million. Therefore, a policy for a PM2.5-standard up to 15 µg m-3 is suggested.

Monetization of the environmental damage caused by fossil fuels.

Fossil fuels account for more than 80% of the world's energy consumption. Constituents of the atmosphere have changed perceptibly due to the increased use of fossil fuels. Therefore, many researchers have tried to relate their effect on society. In Pakistan, fossil fuel consumption and its CO2-based emission factor have been significantly correlated to economic growth. However, it needs further attention to study the adverse effects of fossil fuels. This study is an attempt to assess the cost of fossil fuels to society. Damages caused by fossil fuels are evaluated for the years of 2005-2009, using local pollution factors based on CO2 emission. Results show that the market price of fossil fuels increases after adding up the cost of damage caused by the final use of the fuel. People pay a huge amount of PKR 133 billion per year for taxes, health services, insurance premiums, and low living standards. Accordingly, it is suggested that we must shift from fossil fuels to other alternative clean types of energy.

Green Synthesis of Silver Nanoparticles Using Jurinea dolomiaea and Biological Activities.

Green syntheses of nanoparticles using plant materials are of tremendous scope. Here we report advantageous green synthesis for silver nanoparticles (AgNPs) using aqueous-root extract of Jurinea dolomiaea and AgNO3. Color change of solution and UV-Vis absorption at 444 nm indicated the formation of AgNPs. XRD confirmed their face centered cubic structure (fcc) with average particle size of 24.58 nm. SEM analysis showed their spherical, cubic and triangular structures. FT-IR indicated the presence of functional groups of reducing and stabilizing phytochemicals. Methanol-root extract of J. dolomiaea revealed high flavonoid (445 mg RE/g) and phenolic contents (92 mg GAE/g). Methanol-extract showed high antioxidant potency (IC50 = 0.494 µg/mL), rationally due to its high phenolic and flavonoid contents. These AgNPs showed the highest and equal antimicrobial activities against Escherichia coli and Pseudomonas aeruginosa (Inhibition zone 11.0 mm) whereas, methanol-roots extract showed equal and intermediate activities (Inhibition zone 8.0 mm) against both pathogens but aqueous extract showed poor activities (Inhibition zone 6.0 mm) against these both pathogens. AgNPs are playing a major role in the field of nanotechnology and nanomedicine due to their antimicrobial and drug delivery efficacy as well as reasonable tolerance in human biology.

Biogenic Synthesis of AgNPs with Saussurea lappa C.B. Clarke and Studies on Their Biochemical Properties.

Nanotechnology has become an irreplaceable need and green synthesis of nanoparticles offers several advantages over physical and chemical methods. Medicinal plants are the main reservoirs of drugs and drug candidates. We report the biogenic synthesis of silver nanoparticles (AgNPs) using aqueous root extract of Saussurea lappa. Verification and characterization of these nanoparticles were done by UV-visible spectroscopy, XRD-analysis and Scanning Electron Microscopy and FT-IR. Extract-loaded-AgNPs showed the highest inhibition zone against Escherichia coli (11.0 mm) and intermediate against Pseudomonas aeruginosa (9.0 mm). The methanolic root extract of S. lappa alone, also moderately inhibited Pseudomonas aeruginosa (9.0 mm) and showed lower activity (6.0 mm) against Escherichia coli. Its aqueous roots extract inhibited (6.0 mm) the growth of tested organisms. Methanolic extract showed antioxidant potency (IC50 = 0.814 µg/mL). Experiments revealed the presence of phenols and flavonoids in the roots of Saussurea lappa. These findings provide promising interest to exploit Saussurea lappa for the biogenic synthesis of AgNPs and their biological applications.