| 1. |
- Mahmood, Rashid, et al.
(author)
-
Assessment of antidiabetic potential and phytochemical profiling of Rhazya stricta root extracts
- 2020
-
In: BMC Complementary Medicine and Therapies. - : Springer Nature. - 2662-7671. ; 20:1
-
Journal article (peer-reviewed)abstract
- Background: Diabetes mellitus is a chronic disease characterized by hyperglycemia that may occur due to genetic, environmental or lifestyle factors. Natural remedies have been used to treat diabetes since long and many antidiabetic compounds of varied efficacies have been isolated from medicinal plants. Rhazya stricta has been used for decades for the treatment of diabetes mellitus and associated ailments. Considering the folkloric use of R. stricta against diabetes, it was aimed to investigate the effectiveness of its root extracts against diabetes through in vitro assays and in vivo studies using animal model along with phytochemical profiling through GCMS. Methods: Various fractions of Rhazya stricta obtained through column chromatography were evaluated for a variety of assays including a-glucosidase, Dipeptidyl peptidase-IV (DPP-IV), beta-secretase and Glucagon-like peptide-1 (GLP-1) secretion studies. For the in vivo studies the alloxan-induced diabetic mice were treated with root extracts and blood glucose levels, HbA1C, and other biochemical markers along with the histological study of the liver were done. The phytochemical identification was performed using an Agilent 7890B GC coupled to a 7010 Triple Quadrupole (MS/MS) system. GraphPad Prism software version 5.01 was used for statistical analysis. Results: Majority of the extract fractions showed excellent results against diabetes by inhibiting enzymes DPP-IV (Up to 61%) and beta-secretase (Up to 83%) with IC50s 979 pg/ml and 169 mu g/ml respectively with increase in the GLP1 secretion. The results of in vivo studies indicated a marked reduction in blood glucose and HbA1c levels along with positive effects on other parameters like lipid profile, liver functions and renal functions of extract-treated mice as compared to control. The histological examination of the liver demonstrated hepatoprotective effects against diabetes led changes and various classes of phytochemicals were also identified through GCMS in different fractions. Conclusion: The results revealed strong antidiabetic activity of R. stricta root with the potential to protect body organs against diabetic changes. Moreover, a variety of phytochemicals has also been identified through GCMS that might be responsible for the antidiabetic potential of Rhazya stricta root.
|
|
| 2. |
- Ahsan, Hajra, et al.
(author)
-
Photocatalysis and adsorption kinetics of azo dyes by nanoparticles of nickel oxide and copper oxide and their nanocomposite in an aqueous medium
- 2022
-
In: PeerJ. - : PeerJ. - 2167-8359. ; 10
-
Journal article (peer-reviewed)abstract
- Azo dyes are recalcitrant organic pollutants present in textile industry effluents. Conventional treatment methods to remove them come with a range of disadvantages. Nanoparticles and their nanocomposites offer more efficient, less expensive and easy to handle wastewater treatment alternative. Methods. In this study, nanoparticles of nickel oxide (NiO-NPs), copper oxide (CuO-NPs) and their nanocomposite (NiO/CuO-NC) were synthesized using co- precipitation method. The functional groups present on the surface of synthesized nanomaterials were verified using Fourier-transform infrared spectroscopy (FTIR). Surface morphology was assessed using scanning electron microscopy (SEM) whereas purity, shape and size of the crystallite were determined using X-ray diffraction (XRD) technique. The potential of these nanomaterials to degrade three dyes i.e., Reactive Red-2 (RR-2), Reactive Black-5 (RB-5) and Orange II sodium salt (OII) azo dyes, was determined in an aqueous medium under visible light (photocatalysis). The photodegradation effectiveness of all nanomaterials was evaluated under different factors like nanomaterial dose (0.02-0.1 g 10 mL-1), concentration of dyes (20-100 mg L-1), and irradiation time (60-120 min). They were also assessed for their potential to adsorb RR-2 and OII dyes. Results. Results revealed that at optimum concentration (60 mgL-1) of RR-2, RB-5, and OII dyes, NiO-NPs degraded 90, 82 and 83%, CuO-NPs degraded 49, 34, and 44%, whereas the nanocomposite NiO/CuO-NC degraded 92, 93, and 96% of the said dyes respectively. The nanomaterials were categorized as the efficient degraders of the dyes in the order: NiO/CuO-NC > NiO-NPs > CuO-NPs. The highest degradation potential shown by the nanocomposite was attributed to its large surface area, small particles size, and quick reactions which were proved by advance analytical techniques. The equilibrium and kinetic adsorption of RR-2 and OII on NiO-NPs, CuO-NPs, and NiO/CuO-NC were well explained with Langmuir and Pseudo second order model, respectively (R2 ≥0.96). The maximum RR-2 adsorption (103 mg/g) was obtained with NiO/CuO-NC. It is concluded that nanocomposites are more efficient and promising for the dyes degradation from industrial wastewater as compared with dyes adsorption onto individual NPs. Thus, the nanocomposite NiO/CuO-NC can be an excellent candidate for photodegradation as well as the adsorption of the dyes in aqueous media.
|
|
| 3. |
- Balli, Faruk, et al.
(author)
-
A tale of two shocks: What do we learn from the impacts of economic policy uncertainties on tourism?
- 2018
-
In: Tourism Management. - : ELSEVIER SCI LTD. - 0261-5177 .- 1879-3193. ; 68, s. 470-475
-
Journal article (peer-reviewed)abstract
- In this paper, we investigate the impact of the economic policy uncertainties on the tourism demand, by using multiple and partial wavelet analysis. We find that global economic policy uncertainties (EPUs) impact on tourism demand in various levels for different countries. The effect is on peak and stay longer in certain periods; such as GFC or 9/11. More importantly, novel to the literature, the domestic EPUs significantly affect the tourist inflows, indicating that policy holders need to take into account EPU fluctuations in forecasting the short-term and medium term tourism demand.
|
|
| 4. |
- Balli, Faruk, et al.
(author)
-
Geopolitical risk and tourism demand in emerging economies
- 2019
-
In: Tourism Economics. - : SAGE PUBLICATIONS LTD. - 1354-8166 .- 2044-0375. ; 25:6, s. 997-1005
-
Journal article (peer-reviewed)abstract
- In this article, we investigate the impact of geopolitical risk (GPR) on international tourism demand in emerging economies. We have found that impact of GPR is not homogeneous for every country in our sample; for example, some countries are affected heavily by GPR and others are mostly immune to GPR shocks. In general, for countries that have attractive tourism destinations, the impact of GPR is minimal, indicating that if international tourists desperately want to go a destination, they do not take GPR seriously. In addition, the tsunami impact of GPR is not the same for all affected countries. For some countries, the GPR shocks have an impact within 2 to 3 months of its first hit, while for other countries, the impact is felt over longer periods.
|
|
| 5. |
- Hernandez, Jose Areola, et al.
(author)
-
Can agricultural and precious metal commodities diversify and hedge extreme downside and upside oil market risk? An extreme quantile approach
- 2019
-
In: Resources policy. - : ELSEVIER SCI LTD. - 0301-4207 .- 1873-7641. ; 62, s. 588-601
-
Journal article (peer-reviewed)abstract
- The cost-effectiveness measures for production, processing, and transportation adopted by wheat, rice, and corn farmers, as well as the price fluctuations of gold and silver, doubtlessly depend on the downside and upside price trends of global economic factors such as the oil market. This dependence between oil and agricultural commodities motivates an analysis of interdependence and spillover influence in extreme oil market scenarios. By means of an extreme quantile approach, this study models the return distribution of oil in relation to some of the most traded agricultural and precious metal commodities. We find that extreme lower quantiles of oil returns have a positive effect on the lower quantiles of gold, silver, and rice returns. These effects are more significant using daily-frequency data, while for weekly and monthly frequencies, the effect is less significant. The decrease in oil returns during a bearish oil market will cause a decrease in precious metal and rice returns; therefore, these cannot be used to hedge the downside risk of oil investments, especially in the short term. These commodities might only serve as a diversification strategy for oil investments. The lower quantiles of oil returns have either no effect, or a negative effect, on the lower quantiles of wheat and corn, making them suitable hedges for extreme downturns in oil prices.
|
|
| 6. |
- Hernandez, Jose Arreola, et al.
(author)
-
Regime specific spillovers across US sectors and the role of oil price volatility
- 2022
-
In: Energy Economics. - : ELSEVIER. - 0140-9883 .- 1873-6181. ; 107
-
Journal article (peer-reviewed)abstract
- There is a growing literature studying return spillovers between similar assets and assets of different classes during crisis periods. However, less is known about return spillovers across stock sectors under high and low volatility regimes and whether they are affected by oil price volatility. Using daily data from May 10th, 2007 to February 28th, 2020, we first study the return spillovers between US stock sectors under low and high volatility regimes by implementing a Markov regime-switching vector autoregression with exogenous variables model, while considering the Fama-French factors as conditioning variables. Return spillovers under low and high volatility regimes show that the energy sector is the largest transmitter and receiver of spillovers to/from other US equity sectors. Rolling window analysis shows that spillovers intensified since the outbreak of the COVID19 pandemic. Second, we apply linear and non-linear Granger causality tests from oil price volatility to the spillover indices. The results show evidence that oil volatility has a causal impact on the spillover dynamics of US stock sectors and that the impact is particularly strong in the high volatility regime. Although the energy sector is one of the smallest sectors of the US stock market, it plays a large role in the network connectedness of stock sectors. The results are of interest to individual and institutional investors who consider US equity investments and to policymakers.
|
|
| 7. |
- Hussain Ibupoto, Zafar, et al.
(author)
-
The Synthesis of Functional Cobalt Oxide Nanostructures, and their Sensitive Glucose Sensing Application
- 2017
-
In: Electroanalysis. - : WILEY-V C H VERLAG GMBH. - 1040-0397 .- 1521-4109. ; 29:1, s. 213-222
-
Journal article (peer-reviewed)abstract
- In this study, a novel approach is adapted for the synthesis of new nanostructures of cobalt oxide (Co3O4) by low temperature aqueous chemical growth method in the presence of water soluble amino acids such as L-arginine, L-aspartic acid, L-isoleucine, L-leucine, Lserine and L-threonine. The synthesized nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The nanostructures exhibit well defined morphology and are of high purity. To explore the potential application of the prepared nanostructures of cobalt oxide, the non-enzymatic glucose sensor is developed by modifying the glassy carbon electrode. Serine assisted cobalt oxide nanostructures showed excellent sensitivity of 4169.00 mu A/mMcm(2), wide linear range of 0.01 mM to 20 mM and detection limit was estimated as 0.001 mM (S/N= 3). The analytical parameters for the serine assisted cobalt oxide nanostructures based glucose sensor were evaluated and it was found that the sensor is highly selective, reproducible, repeatable, reversible, and stable. Finally, the practical application of the serine assisted cobalt oxide nanostructures based glucose sensor was examined by measuring the glucose concentrations from real human blood samples.
|
|
| 8. |
- Hussain, Syed Asad, et al.
(author)
-
Multilevel classification of security concerns in cloud computing
- 2017
-
In: Applied Computing and Informatics. - : Elsevier B.V.. - 2210-8327. ; 13:1, s. 57-65
-
Journal article (peer-reviewed)abstract
- Threats jeopardize some basic security requirements in a cloud. These threats generally constitute privacy breach, data leakage and unauthorized data access at different cloud layers. This paper presents a novel multilevel classification model of different security attacks across different cloud services at each layer. It also identifies attack types and risk levels associated with different cloud services at these layers. The risks are ranked as low, medium and high. The intensity of these risk levels depends upon the position of cloud layers. The attacks get more severe for lower layers where infrastructure and platform are involved. The intensity of these risk levels is also associated with security requirements of data encryption, multi-tenancy, data privacy, authentication and authorization for different cloud services. The multilevel classification model leads to the provision of dynamic security contract for each cloud layer that dynamically decides about security requirements for cloud consumer and provider. © 2016 King Saud University
|
|
| 9. |
- Lal, Ramesh, et al.
(author)
-
Chemically Coupled Multiwall Carbon Nanotubes with Leaf-Like Nanostructures of NiO for Sensitive and Selective Determination of Uric Acid
- 2021
-
In: Journal of Electronic Materials. - : SPRINGER. - 0361-5235 .- 1543-186X. ; 50:5, s. 2852-2859
-
Journal article (peer-reviewed)abstract
- The chemical coupling of NiO nanostructures with thermally treated multiwall carbon nanotubes (MWCNTs) is not reported as it provides an enhanced dispersion of composite material in water. The dispersion of MWCNTs has been considered a big challenge. For this purpose, we first thermally treated MWCNTs at 1000 degrees C in air for 30 min. Then, thermally treated MWCNTs were chemically coupled with NiO nanostructures by a hydrothermal method. The material characterization in terms of structure, morphology, and composition is well studied by different analytical techniques. The NiO composite (sample 2) with highest weight of MWCNTs had a leaf-like morphology and it exhibits a cubic phase of NiO. Cyclic voltammetry (CV) was used to study the electrochemical activity of prepared composite material towards the oxidation of uric acid in the phosphate buffer solution of pH 7.0. Sample 2 showed a well-behaved anodic peak with enhanced peak current and exhibited a linear range from 0.01 mM to 2.5 mM for uric acid with a low limit of detection 0.001mM. Sample 2 was found to be very selective under the environment of competing interferents such as urea, glucose, lactic acid and ethanol. This sample exhibits significant stability, thus it is a potential protocol for the monitoring of uric acid from real samples. This study provides a low-cost platform for the fabrication of efficient materials for various applications such as batteries, fuel cells and water splitting.
|
|
| 10. |
- Rahman, Md Lutfur, et al.
(author)
-
Comparing the Risk Spillover from Oil and Gas to Investment Grade and High-yield Bonds through Optimal Copulas
- 2022
-
In: Energy Journal. - : INT ASSOC ENERGY ECONOMICS. - 0195-6574 .- 1944-9089. ; 43:1, s. 215-
-
Journal article (peer-reviewed)abstract
- This paper compares the tail dependence and risk spillovers from the oil and gas to high-yield (HY) and investment grade (IG) bond markets. We use time-varying optimal copula framework to examine the dependence and further quantify upside and downside risk spillovers. We also explore how energy futures can be used to hedge risk of HY and IG bond portfolios. Our results show that the bond returns are more sensitive to risk shocks in the oil market compared to gas market. We find both negative and positive tail dependence between the bond and energy pairs and the relationship is stronger during the oil-crunch period. The dependence however is asymmetric across the tails. Finally, compared to oil futures, gas futures are found to be better hedge for the bond investment. These results can help in managing portfolio risk and designing optimal asset allocation strategies. These might also assist in formulating policies and regulations to manage the effects of cross-market risk transmissions.
|
|
| 11. |
- Rasool, Kashif, et al.
(author)
-
Comprehensive insights into sustainable conversion of agricultural and food waste into microbial protein for animal feed production
- 2023
-
In: Reviews in Environmental Science and Biotechnology. - : Springer. - 1569-1705 .- 1572-9826. ; 22:2, s. 527-562
-
Research review (peer-reviewed)abstract
- The growing global population and higher living standards instantly demand the transition in the direction of a sustainable food system. A substantial section of means and agricultural lands are presently committed to protein-rich feed production to rear livestock for human consumption. Conversely, accelerated farming activities and the food industry have rendered a drastic increase in waste which impair the economic and environmental sustainability of the ecosystem. This situation emerges the need for developing an integrated technology for waste management and to improve sustainability footprints. Microbial protein (MP) production based on renewable electron and carbon sources has the potential as a substitute protein source. MP production for animal feed use is growing fast and is derived from bacteria, algae, and fungi including yeast. MP produced from all types of microbes is currently commercialized and in use. However, novel methods and processes are also under investigation to make MP production more economical and sustainable. Current research on MP has concentrated on the valorization of waste materials by using high protein content-containing microorganisms, which can then be used in animal feed. Using such kind of integrated approach, the agroindustry waste resources upcycling can contribute towards finding sustainable, cheaper, and environment-friendly protein sources. This review first describes the potential waste feedstock for MP production and summarizes the recent progress in the application of MP-producing microorganisms including fungus, yeast, bacteria, and phototrophic microbes. Bioprocesses, and production technology advances for MP production have been explored and discussed in detail. Finally, the MP application as animal feed, its challenges, and future perspectives in research have been evaluated.
|
|
| 12. |
- Rehman, Mobeen Ur, et al.
(author)
-
Precious metal returns and oil shocks: A time varying connectedness approach
- 2018
-
In: Resources policy. - : ELSEVIER SCI LTD. - 0301-4207 .- 1873-7641. ; 58, s. 77-89
-
Journal article (peer-reviewed)abstract
- This paper examines the impact of oil shocks on precious metal returns using structural vector autoregression (SVAR) model proposed by Kilian and Park (2009). We capture variability in the effects through rolling window impulse response functions and by extending the dynamic connectedness approach of Diebold and Yilmaz (2014) using structural forecast error variance decomposition. We report time varying effect of disintegrated structural oil shocks on precious metal returns with a significant increase during the global financial crisis period of 2008-09. Our results also indicate that the aggregate demand shocks have most significant spillover effect on the precious metals except gold. We also report that oil specific demand shocks have highest impact on gold during the financial crisis and palladium having possible hedging opportunities against oil price movement. These findings have important investment implications for individual and institutional investors.
|
|
| 13. |
- Shahzad, Danish, et al.
(author)
-
Novel C-2 Symmetric Molecules as -Glucosidase and -Amylase Inhibitors : Design, Synthesis, Kinetic Evaluation, Molecular Docking and Pharmacokinetics
- 2019
-
In: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 24:8
-
Journal article (peer-reviewed)abstract
- A series of symmetrical salicylaldehyde-bishydrazine azo molecules, 5a-5h, have been synthesized, characterized by H-1-NMR and C-13-NMR, and evaluated for their in vitro -glucosidase and -amylase inhibitory activities. All the synthesized compounds efficiently inhibited both enzymes. Compound 5g was the most potent derivative in the series, and powerfully inhibited both -glucosidase and -amylase. The IC50 of 5g against -glucosidase was 0.35917 +/- 0.0189 mu M (standard acarbose IC50 = 6.109 +/- 0.329 mu M), and the IC50 value of 5g against -amylase was 0.4379 +/- 0.0423 mu M (standard acarbose IC50 = 33.178 +/- 2.392 mu M). The Lineweaver-Burk plot indicated that compound 5g is a competitive inhibitor of -glucosidase. The binding interactions of the most active analogues were confirmed through molecular docking studies. Docking studies showed that 5g interacts with the residues Trp690, Asp548, Arg425, and Glu426, which form hydrogen bonds to 5g with distances of 2.05, 2.20, 2.10 and 2.18 angstrom, respectively. All compounds showed high mutagenic and tumorigenic behaviors, and only 5e showed irritant properties. In addition, all the derivatives showed good antioxidant activities. The pharmacokinetic evaluation also revealed promising results
|
|
| 14. |
- Shahzad, Syed Jawad Hussain, et al.
(author)
-
Asymmetric interdependence between currency markets volatilities across frequencies and time scales
- 2021
-
In: International journal of finance and economics. - : WILEY. - 1076-9307 .- 1099-1158.
-
Journal article (peer-reviewed)abstract
- We investigate the dynamics of interdependence between realized variances and realized semivariances of six major currencies across frequencies and time scales. The empirical results are derived, first, through constructing daily measures of realized variance and semivariance from a high frequency 5-min interval data, and second, by fitting wavelet squared coherence and wavelet cohesion measure with time-varying weights. The realized volatilities of the currencies and their cross-currency influences are found to increase during the global financial crisis. The realized volatilities of the Euro, Swiss Franc, and British Pound are closely synchronized over the short-term horizon. However, over the long-run, the Euro, Swiss Franc, and Japanese Yen lead the realized volatilities of the British Pound, Australian Dollar, and Canadian Dollar. The synchronization structure of positive and negative realized volatilities indicates asymmetric dependence among the currencies across time horizons. We further observe strong positive (negative) cohesion among the realized volatilities over the medium- and long-term horizons. Finally, significant counter cyclical comovements among the currencies are observed over the medium- and long-term horizons. These findings have important implications for foreign exchange portfolio managers.
|
|
| 15. |
- Shahzad, Syed Jawad Hussain, et al.
(author)
-
Re-examining the real option characteristics of gold for gold mining companies
- 2021
-
In: Resources policy. - : ELSEVIER SCI LTD. - 0301-4207 .- 1873-7641. ; 70
-
Journal article (peer-reviewed)abstract
- This paper re-examines the static and time-varying asymmetries in quantile-specific relationship between gold returns and gold mining companies stock returns. In doing so, we use novel cross-quantilogram approach that is built on quantiles of both distributions and control for the effect of crude oil price changes, overall stock market movements, stock market volatility and economic policy uncertainty. We find that the gold returns negatively predict the gold stock returns around the median quantile. Whereas the gold returns positively depend on the gold mining companies stock returns in the low and high quantiles. We therefore, support for an embedded real option in gold for gold mining companies which is time-varying and occurs in very short-run. This finding is useful for devising portfolio allocation and diversification strategies.
|
|
| 16. |
- Uddin, Gazi Salah, et al.
(author)
-
Characteristics of spillovers between the US stock market and precious metals and oil
- 2020
-
In: Resources policy. - : ELSEVIER SCI LTD. - 0301-4207 .- 1873-7641. ; 66
-
Journal article (peer-reviewed)abstract
- This study examines the characteristics of the risk spillover under extreme market scenarios between the US stock market and precious metals (gold, silver, platinum) and oil using a copula approach for tail dependence and conditional value-at-risk (CoVaR) spillover measures. The results indicate asymmetric tail dependence of the US stock market with silver and platinum, profound during market downturns. Gold and oil symmetrically co-move with the US stock market under normal and extreme market scenarios. Silver and platinum most strongly influence US stock market in the downside, while oil does it on the upside. The US stock market most strongly influences oil and silver under both market downturns and upturns. Gold weakly spillover to the US stock market, suggesting that investors can use gold as an equity portfolio diversifier.
|
|
| 17. |
- Uddin, Gazi Salah, et al.
(author)
-
Heterogeneous interconnections between precious metals: Evidence from asymmetric and frequency-domain spillover analysis
- 2019
-
In: Resources policy. - : ELSEVIER SCI LTD. - 0301-4207 .- 1873-7641. ; 64
-
Journal article (peer-reviewed)abstract
- We examine the spillover characteristics of returns and volatilities of precious metals: gold, silver, platinum and palladium. We find evidence of homogenous and time varying asymmetric spillovers between the returns and volatilities of the precious metals suggesting similarities in their cyclical relationship with global and local fundamentals. Negative and positive shocks cause the asymmetric spillovers and are more pronounced in times of financial turmoil. The largest transmission of net spillovers is exerted by gold and silver. Silver in the short and long runs and in good and bad market conditions leads the spillover transmission. The pairs silver-gold and palladium-platinum display the largest directional spillovers. Lastly, while palladium and platinum act mainly as spillover receivers, gold and silver act mainly as transmitters of spillovers. Implications of the results are discussed.
|
|
| 18. |
- Uddin, Gazi Salah, et al.
(author)
-
Multivariate dependence and spillover effects across energy commodities and diversification potentials of carbon assets
- 2018
-
In: Energy Economics. - : ELSEVIER SCIENCE BV. - 0140-9883 .- 1873-6181. ; 71, s. 35-46
-
Journal article (peer-reviewed)abstract
- In a first step, we model the multivariate tail dependence structure and spillover effects across energy commodities such as crude oil, natural gas, ethanol, heating oil, coal and gasoline using canonical vine (C-vine) copula and c-vine conditional Value-at-Risk (CoVaR). In the second step, we formulate portfolio strategies based on different performance measures to analyze the risk reduction and diversification potential of carbon assets for energy commodities. We identify greater exposure to losses arising from investments in heating oil and ethanol markets. We also find evidence of carbon asset providing diversification benefits to energy commodity investments. These findings motivate for regulatory adjustments in the trading and emission permits for the energy markets most strongly diversified by carbon assets. (C) 2018 Published by Elsevier B.V.
|
|
| 19. |
- Uddin, Gazi Salah, et al.
(author)
-
Supply and demand driven oil price changes and their non-linear impact on precious metal returns: A Markov regime switching approach
- 2018
-
In: Energy Economics. - : ELSEVIER SCIENCE BV. - 0140-9883 .- 1873-6181. ; 73, s. 108-121
-
Journal article (peer-reviewed)abstract
- This paper examines the nonlinear effect of oil price shocks on precious metal returns using Markov regime switching regression. We use Readys (2018) approach to decompose oil price changes into supply, demand, and risk driven shocks. Results indicate a significant positive impact of demand and supply shocks and a negative impact of risk shocks on precious metal returns. Although we find evidence of switching between low and high volatility regimes, we do not find strong regime effect on supply or demand shocks contemporaneous relationship with precious metal returns. However, risk shocks influence on precious metal returns is strongly regime dependent. These results generally hold for different distributional specification of error terms. (C) 2018 Elsevier B.V. All rights reserved.
|
|
| 20. |
- Uddin, Gazi Salah, et al.
(author)
-
Time-varying evidence of efficiency, decoupling, and diversification of conventional and Islamic stocks
- 2018
-
In: International Review of Financial Analysis. - : ELSEVIER SCIENCE INC. - 1057-5219 .- 1873-8079. ; 56, s. 167-180
-
Journal article (peer-reviewed)abstract
- This study investigates the efficiency of conventional and Islamic stock markets and their diversification potential by using multifractal de-trended fluctuation analysis (MF-DFA), wavelet squared coherence (WTC) and wavelet Value-at-Risk (VaR). Evidence from regional and country-level markets indicates Islamic stocks are less efficient than conventional ones in the short term, however more efficient in the medium term. Conventional stocks in the UK, Japan, and emerging markets are more efficient than the Islamic ones in the long term, whereas those from the US and Europe are less efficient. The wavelet VaR shows that conventional stock markets are at least as risky as the Islamic ones.
|
|
| 21. |
- Ullah, Hameed, et al.
(author)
-
Polyoxometalate based ionic liquids reinforced on magnetic nanoparticles: A sustainable solution for microplastics and heavy metal ions elimination from water
- 2024
-
In: Microchemical journal (Print). - : Elsevier. - 0026-265X .- 1095-9149. ; 204
-
Journal article (peer-reviewed)abstract
- To purify water from contaminents is essential for life on universe. Here, in this manuscript we introduces an innovative approach to overcome the intricate challenge of eliminating heavy metal ions and microplastics from water. We designed a mesoporous composite materials by synergistically integrating polyoxometalates (POMs) based ionic liquids with silica coated magnetic nanoparticles. The synthesis process initiates with the utilization of highly reduced molybdenum aggregates in polyoxometalate-ionic liquids, reinforced onto magnetic nanoparticles (POM–IL–MNPs). Crafted composites, including Q8[Mo64Ni8La6]@SiO2@Fe3O4, Q10[Mo64Ni8La6]@SiO2@Fe3O4, Q8[Mo176/Mo248]@SiO2@Fe3O4, and Q10[Mo176/Mo248]@SiO2@Fe3O4, are meticulously designed by substituting POM counter cations with long-chain alkyl-based quaternary ammonium salts. The ionic liquids and composites exhibit remarkable hydrophobicity and thermal stability due to large anions and long-chain organic counter cations. Comprehensive characterization, including FT–IR, UV–vis spectroscopy, TGA, DSC, CV, rheological study, elemental analysis, and ICP-AES, ensures a thorough investigation. Additional analyses, such as Powder X-ray diffraction (PXRD), SEM, EDX, DLS, N2 adsorption, and VSM, reveal amorphous crystallinity, distinctive surface morphology, and substantial specific surface area. Core shell structure of POM-IL-MNPs was determined by Transmision electron microscope (TEM), ICP-AES analysis demonstrates metal ion removal efficiencies from 87.35% to 99.98%, with DLS confirming 100% efficiency in PVC beads elimination. This research not only advances water decontamination but also provides valuable insights into designing and characterizing novel materials with promising environmental applications.
|
|
| 22. |
- Thomas, HS, et al.
(author)
-
- 2019
-
swepub:Mat__t
|
|
