Cobalt Encapsulated in Nitrogen-Doped Graphite-like Shells as Efficient Catalyst for Selective Oxidation of Arylalkanes.

Selective oxidation of ethylbenzene to acetophenne is an important process in both organic synthesis and fine chemicals diligence. The cobalt-based catalysts combined with nitrogen-doped carbon have received great attention in ethylbenzene (EB) oxidation. Here, a series of cobalt catalysts with metallic cobalt nanoparticles (NPs) encapsulated in nitrogen-doped graphite-like carbon shells (Co@NC) have been constructed through the one-pot pyrolysis method in the presence of different nitrogen-containing compounds (urea, dicyandiamide and melamine), and their catalytic performance in solvent-free oxidation of EB with tert-butyl hydrogen peroxide (TBHP) as an oxidant was investigated. Under optimized conditions, the UCo@NC (urea as nitrogen source) could afford 95.2% conversion of EB and 96.0% selectivity to acetophenone, and the substrate scalability was remarkable. Kinetics show that UCo@NC contributes to EB oxidation with an apparent activation energy of 32.3 kJ/mol. The synergistic effect between metallic cobalt NPs and nitrogen-doped graphite-like carbon layers was obviously observed and, especially, the graphitic N species plays a key role during the oxidation reaction. The structure-performance relationship illustrated that EB oxidation was a free radical reaction through 1-phenylethanol as an intermediate, and the possible reaction mechanistic has been proposed.

Tailoring Defect Density in UiO-66 Frameworks for Enhanced Pb(II) Adsorption.

Defect engineering of metal organic frameworks offers potential prospects for tuning their features toward particular applications. Herein, two series of defective UiO-66 frameworks were synthesized via changing the concentration of the linker and synthetic temperature of the reaction. These defective materials showed a significant improvement in the capability of Pb(II) removal from wastewater. This strategy for defect engineering not only created additional active sites, more open framework, and enhanced porosity but also exposed more oxygen groups, which served as the adsorption sites to improve Pb(II) adsorption. A relationship among degree of defects, texture features, and performances for Pb(II) removal was successfully developed as a proof-of-concept, highlighting the importance of defect engineering in heavy metal remediation. To investigate the kinetic and adsorption isotherms, we performed adsorption experiments influenced by the time and concentration of the adsorbate, respectively. For the practicality of the materials, the most significant parameters such as pH, temperature, adsorbent concentration, selectivity, and recyclability as well as simulated natural surface water were also examined. This study provides a clue for the researchers to design other advanced defective materials for the enhancement of adsorption performance by tuning the defect engineering.

Developing a forecasting model for cholera incidence in Dhaka megacity through time series climate data.

Cholera, an acute diarrheal disease spread by lack of hygiene and contaminated water, is a major public health risk in many countries. As cholera is triggered by environmental conditions influenced by climatic variables, establishing a correlation between cholera incidence and climatic variables would provide an opportunity to develop a cholera forecasting model. Considering the auto-regressive nature and the seasonal behavioral patterns of cholera, a seasonal-auto-regressive-integrated-moving-average (SARIMA) model was used for time-series analysis during 2000-2013. As both rainfall (r = 0.43) and maximum temperature (r = 0.56) have the strongest influence on the occurrence of cholera incidence, single-variable (SVMs) and multi-variable SARIMA models (MVMs) were developed, compared and tested for evaluating their relationship with cholera incidence. A low relationship was found with relative humidity (r = 0.28), ENSO (r = 0.21) and SOI (r = -0.23). Using SVM for a 1 °C increase in maximum temperature at one-month lead time showed a 7% increase of cholera incidence (p < 0.001). However, MVM (AIC = 15, BIC = 36) showed better performance than SVM (AIC = 21, BIC = 39). An MVM using rainfall and monthly mean daily maximum temperature with a one-month lead time showed a better fit (RMSE = 14.7, MAE = 11) than the MVM with no lead time (RMSE = 16.2, MAE = 13.2) in forecasting. This result will assist in predicting cholera risks and better preparedness for public health management in the future.

A case report of Munchausen syndrome presenting with bleeding from ear: a rare factitious disorder.

Munchausen syndrome is a rare psychiatric illness that includes mimicking a group of medical conditions, in which a person repeatedly harms him or herself or falsely misinterprets any medical condition when he or she is not actually sick, in order to achieve health care attention. Underdiagnosis of this syndrome leads to irrelevant use of medical assets. Here, we document an interesting and rare case of a young girl presented in the outpatient department of the Otolaryngology department of Patel Hospital with episodes of bleeding from her ear, which is a rare presentation of Munchausen syndrome. Her complete physical, otolar yngological, haematological and radiological examination failed to reveal any clue towards a particular diagnosis. Hence a diagnosis of Munchausen syndrome was made by exclusion of other possibilities of ear bleeding, and it was considered as a case report after taking duly signed written consent from the patient. This report will help in increasing the self-knowledge and perception of different clinical based presentations of this syndrome in medical practitioners, in order to avoid overlooking such cases. Further exploratory work is required in this regard to discover the etiology and predisposing factors and to develop new treatment strategies.

Design of Gravel-Sand Filter for Arsenic Removal: A Case Study of Muzaffargarh District in Pakistan.

Arsenic decontamination of drinking water has grabbed significant attention due to arsenic's serious effects on health. A novel gravel-sand filter (GSF) holding zero-valent iron plates was designed and constructed in Muzaffargarh district (Pakistan) for arsenic removal from drinking water with lower iron concentration (0.3 ppm). The GSF efficiently removed arsenic up to 99.99% with long-term stability. The GSF provides 800 liters of arsenic-free drinking water in 39 hours with a rate of 2.5 L/h. A tentative mechanism for arsenic removal is evaluated and described on the basis of oxidation-coagulation-adsorption processes. Chemical composition of underground water is also analyzed and discussed. This GSF design will open a new avenue for arsenic removal and can be extended to other parts of the world.

Evaluating the role of renewable energy and technology innovations in lowering CO2 emission: a wavelet coherence approach.

Environmental sustainability is one of the most critical issues that require efficient environmental and economic policies in modern times. Advancements in renewables and green technologies contribute significantly to sustained long-term development without affecting environmental quality. Several studies focus on the association of carbon dioxide emissions (CO2e) with economic variables. However, they ignored the impact of technological innovations and renewable energy consumption on CO2e in developed countries. Therefore, this study examines the relationship between CO2e, energy consumption, gross domestic product (GDP), renewable energy consumption, and technology innovations in G-7 countries by employing cross-sectionally augmented autoregressive distributed (CS-ARDL) lag and wavelet coherence techniques during 1990-2020. The results depict that GDP and renewable energy consumption are inversely related to CO2e. A 1% increase in CO2e will decrease GDP and renewable energy consumption by 0.459 and 0.172% in the long run and by 0.471 and 0.183% in the short run in G7 countries. Technology innovations negatively impact CO2e in the short run while positively influencing it in the long run. Considering the advancements in green technologies in different energy-dependent and manufacturing sectors is crucial for a sustainable environment in the long run. Such initiatives ensure the effective use of energy sources by limiting CO2e in the atmosphere. Moreover, the dynamic common correlated effects mean group model confirms the reliability and effectiveness of the CS-ARDL. The wavelet coherence approach revealed a causality relation between CO2e and technology innovation in Italy, Japan, the UK, and the USA during the study period.

Turning precious metal-loaded e-waste to useful catalysts: Investigation into supercilious recovery and catalyst viability for peroxymonosulfate activation.

Here, the key tasks to be accomplished are selective precious metal recovery from e-wastewater and their conversion into valuable catalysts for peroxymonosulfate (PMS) activation. In this regard, we developed a hybrid material using 3D functional graphene foam and copper para-phenylenedithol (Cu-pPDT) MOF. The prepared hybrid showed a supercilious recovery of 92-95% even up to five cycles for Au(III) and Pd(II), which can be viewed as a reference for both the 2D graphene and the MOFs family. The outstanding performance has been attributed principally to the impact of diverse functionality as well as the unique morphology of 3D graphene foam, which provided a wide range of surface area and additional active sites in the hybrid frameworks. To prepare the surface-loaded metal nanoparticle catalysts, the sorbed samples recovered after precious metal extraction were calcined at 800 °C. The viability of the developed catalysts for the breakdown of 4-nitrophenol (4-NP) via PMS activation was investigated. Electron paramagnetic resonance spectroscopy (EPR) and experiments with radical scavengers suggest that sulfate and hydroxyl radicals are the main reactive species involved in the breakdown of 4-NP. This is because the active graphitic carbon matrix and the exposed precious metal and copper active sites work together in a way that is more effective.

Singlet oxygen dominance for phenolic degradation mediated by mixed-valence FeOx nanospheres.

In this investigation, we successfully synthesized magnetic FeOx nanosphere catalysts with mixed-valence and high operational stability through the pyrolysis of a hybrid material containing polyferrocenlyphosphazene with coordinating heteroatoms (N, P, O). We evaluated the degradation performance of these catalysts using the peroxymonosulfate (PMS) activation process against four different phenolic compounds, namely phenol, 4-nitrophenol, 2,4-dinitrophenol, and 2,4,5-trinitrophenol. Our results demonstrate the significant role of FeOx in the degradation process. The presence of mixed iron species, such as ferric iron, zero-valent iron, and iron oxides, activated PMS to generate radicals. Additionally, the heteroatoms facilitated the anchoring and dispersion of FeOx nanospheres while also breaking the inertness of the carbon structure. Notably, the FeOx-800 catalyst exhibited a maximum degradation activity of 98% for phenol, surpassing its counterparts. Electron paramagnetic resonance and free radical scavenging experiments confirmed that singlet oxygen (1O2) is the principal reactive oxygen species (ROS) that leads to the oxidative breakdown of phenolic compounds. This study introduces new concepts for designing Fenton-like catalysts incorporating heteroatoms into the carbon matrix. Due to their low cost and non-toxicity, these catalysts have recently received a great deal of attention for peroxymonosulfate (PMS) activation and environmental remediation.

Phosphazene Cyclomatrix Network-Based Polymer: Chemistry, Synthesis, and Applications.

Polyphosphazenes are an inorganic molecular hybrid family with multifunctional properties due to their wide range of organic substitutes. This review intends to propose the basics of the synthetic chemistry of polyphosphazene, describing for researchers outside the field the basic knowledge required to design and prepare polyphosphazenes with desired properties. A special emphasis is placed on recent advances in chemical synthesis, which allow not only the synthesis of polyphosphazenes with controlled molecular weights and polydispersities but also the synthesis of novel branched designs and block copolymers. We also investigated the synthesis of polyphosphazenes using various functional materials. This review aims to assist researchers in synthesizing their specific polyphosphazene material with unique property combinations, with the hope of stimulating further research and even more innovative applications for these highly interesting multifaceted materials.

Can Financial Institutional Deepening and Renewable Energy Consumption Lower CO2 Emissions in G-10 Countries: Fresh Evidence from Advanced Methodologies.

To tackle the challenges associated with global warming and climate change, several countries set their targets to lower carbon emissions in accordance with COP21 (Paris Conference). Even though studies highlighted the different aspects that contribute to environmental degradation, there still exists the scarcity of adequate research that emphasizes the environmental implications of financial institutional deepening, renewable energy consumption (REC), and technology innovations. Therefore, this study investigated the significance of financial institutional deepening, REC, gross domestic product (GDP), imports, exports, and technology innovations to achieve sustainability in G-10 countries, namely The Netherlands, Germany, France, Switzerland, United Kingdom, Sweden, Japan, Belgium, Canada, and Italy from 1990 to 2020. The results obtained from cross-sectionally augmented autoregressive distributed lag (CS-ARDL) and the dynamic common correlated effects mean group (DCCEMG) models reveal that financial institutional deepening and imports positively impact CO2 emissions (CO2e) both in the long and short run. A 1% increase in financial institutional deepening and import will increase CO2e by 0.5403% and 0.2942% in the short run and 0.2980% and 0.1479% in the long run levels, respectively. Contrary to this, REC, GDP, exports, and technology innovations improve environmental quality in these countries. The Dumitrescu & Hurlin causality test shows bidirectional causality between imports and CO2e, GDP and CO2e, exports and CO2e, and financial institutional deepening and CO2e, compared to unidirectional causality from technology innovations to CO2e and from REC to CO2e. Apart from this, the outcomes suggest that policymakers in G-10 countries have to consider their financial markets and firms to revise their current environmental policies.

Financial Institutional and Market Deepening, and Environmental Quality Nexus: A Case Study in G-11 Economies Using CS-ARDL.

This study presents a new insight into the dynamic relationship between financial institutional deepening (FID), financial deepening, financial market deepening (FMD), foreign direct investment (FDI), economic growth (GDP), population, and carbon dioxide emissions (CO2e) in the G-11 economies by employing a cross-sectionally augmented autoregressive distributed lag (CS-ARDL) approach during 1990-2019. The outcomes from the CS-ARDL and dynamic common correlated effects mean group (DCCEMG) models shows that financial deepening, GDP, FDI, and population degraded environmental quality both in the short run and the long run. Contrary to this, FID and FMD improves environmental quality in these countries. The government should work to maximize financial institutions (access, depth, efficiency) and financial markets (access, depth, efficiency) to reduce the CO2e. A strong positive and in-phase correlation of CO2e with economic growth and population is observed for G-11 countries. These results suggest policy makers should further improve financial institutions by creating opportunities for their populations. Moreover, the governments of G-11 countries should revise their foreign direct investment policies and attention should be given to import efficient means of energy production.

Fabrication of Bimetallic Cu-Ag Nanoparticle-Decorated Poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) and Its Enhanced Catalytic Activity for the Reduction of 4-Nitrophenol.

We reported a study on the preparation of bimetallic Ag-Cu nanoparticles (NPs) impregnated on PZS poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) nanotubes via a facile and efficient reduction method. Herein, PZS nanotubes consisting of enriched hydroxyl groups are fabricated through an in situ template method, and then, fluctuating the amount ratios of Cu and Ag precursors, bimetallic NPs can be fabricated on readily prepared PZS nanotubes using NaBH4 as a reductant, which results in a series of bimetallic catalysts having tunable catalytic activity. The characterization investigations of scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy results show that Ag-Cu bimetallic NPs are well-dispersed, ultrasmall in size, and well-anchored on the surface of PZS nanotubes. In addition, to examine the catalytic activity and reusability of these nanocomposites, reduction of 4-nitrophenol to 4-aminophenol is utilized as a prototype reaction. The optimized Ag-Cu NPs with a copper ratio of 0.3% are well-stabilized by the organic-inorganic poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) nanotubes. The obtained results show that bimetallic NPs have remarkably higher catalytic ability than that of their monometallic counterparts with maximum catalytic activity. These results are even better than those of noble metal-based bimetallic catalysts and pave the avenue to utilize the polyphosphazene polymer as a substrate material for highly effective bimetallic catalysts.

Ultra-deep removal of Pb by functionality tuned UiO-66 framework: A combined experimental, theoretical and HSAB approach.

A specific functionality in the adsorbent materials plays a significant role for the selective capture of heavy metals based on Pearson's Hard-Soft-Acid-Base (HSAB) concept. Herein, we introduced single and double amino- and thiol-functionalities into the UiO-66 framework, which acted as hard and soft base sites for heavy metal adsorption, respectively. The synthesized adsorbents (labelled as NH2-UiO-66, (NH2)2-UiO-66, SH-UiO-66 and (SH)2-UiO-66) were applied for the selective removal of lead (Pb) ions from contaminated water. The removal efficiency of Pb was about 64, 85, 75 and 99% (pH = 6, T = 30 °C, sample dosage = 10 mg, Pb concentration = 100 mg L-1), respectively, based on available number of interacting sites in the respective adsorbent. To elaborate HSAB concept, the interacting sites of these functional groups towards Pb were explored by identifying their possible types of interactions in terms of soft acid-base affinity, coordinate and covalent bonding, chelation, π-π interactions and synergetic effect of bonding. Density functional theory (DFT) simulation was used to confirm these interactions and to help the better understanding of adsorption mechanism. Model fitting and characterization of Pb-sorbed adsorbents were also performed to reveal kinetics, order of adsorptive reaction, thermodynamics and adsorption mechanism. Moreover, the optimization of adsorptive removal was performed by controlled parameters including time, initial concentration, pH and temperature. The reusability and selectivity of these adsorbents along with recovery of Pb(II) were also assessed. This study presents the conceptual framework for the design of functional adsorbents in the removal of heavy metals using the HSAB principle as an intended guideline.

Effective Poly (Cyclotriphosphazene-Co-4,4'-Sulfonyldiphenol)@rGO Sheets for Tetracycline Adsorption: Fabrication, Characterization, Adsorption Kinetics and Thermodynamics.

The development of excellent drug adsorbents and clarifying the interaction mechanisms between adsorbents and adsorbates are greatly desired for a clean environment. Herein, we report that a reduced graphene oxide modified sheeted polyphosphazene (rGO/poly (cyclotriphosphazene-co-4,4'-sulfonyldiphenol)) defined as PZS on rGO was used to remove the tetracycline (TC) drug from an aqueous solution. Compared to PZS microspheres, the adsorption capacity of sheeted PZS@rGO exhibited a high adsorption capacity of 496 mg/g. The adsorption equilibrium data well obeyed the Langmuir isotherm model, and the kinetics isotherm was fitted to the pseudo-second-order model. Thermodynamic analysis showed that the adsorption of TC was an exothermic, spontaneous process. Furthermore, we highlighted the importance of the surface modification of PZS by the introduction of rGO, which tremendously increased the surface area necessary for high adsorption. Along with high surface area, electrostatic attractions, H-bonding, π-π stacking and Lewis acid-base interactions were involved in the high adsorption capacity of PZS@rGO. Furthermore, we also proposed the mechanism of TC adsorption via PZS@rGO.

Synthesis of γ-alumina (Al2O3) nanoparticles and their potential for use as an adsorbent in the removal of methylene blue dye from industrial wastewater.

Non-toxic nanomaterials have gained significant importance recently in the treatment of industrial wastewater that sometimes contains organic dyes such as methylene blue. We report here an easy approach for the synthesis of γ-alumina (Al2O3) nanoparticles via a method that incorporates the use of formamide and the non-ionic surfactant Tween-80. Together, formamide and Tween-80 serve as an effective precipitating agent and a convenient synthetic template, respectively, in directing the growth of the alumina nanoparticles. The morphology and structure of the nanoparticles were investigated by FT-IR, XRD, TGA, SEM, EDX, elemental mapping and TEM methods. The sizes of the nanoparticles are in the 30-50 nm range. The maximum pore size is 4.13 nm and the surface area is 112.9 m2 g-1 as determined by the Brunauer-Emmett-Teller (BET) method. The nanomaterials are excellent adsorbents for the cationic methylene blue dye from aqueous solution. The effects of pH, time, temperature and concentration on the adsorption have been examined and the adsorption capacity increased from 490 to 2210 mg g-1 as the initial concentration was increased from 50 to 400 mg L-1 under the following conditions: pH 9, 10 min reaction time, and 60 °C. The adsorption mechanism is considered to encompass electrostatic interactions in water between the Al2O3 nanoparticles and the cationic methylene blue dye. These readily made nanoparticles may well prove useful in both wastewater treatment and industrial catalysis.

Correction: Synthesis of γ-alumina (Al2O3) nanoparticles and their potential for use as an adsorbent in the removal of methylene blue dye from industrial wastewater.

[This corrects the article DOI: 10.1039/C8NA00014J.].

Morphology Control of Novel Cross-Linked Ferrocenedimethanol Derivative Cyclophosphazenes: From Microspheres to Nanotubes and Their Enhanced Physicochemical Performances.

Polyphosphazenes have grabbed focal attention in materials research due to their structural diversity, intrinsic backbone stability, and capability to form hybrid molecules. Herein, for the first time, we report morphology-controlled cross-linked hybrid nanotubes and microspheres composed of a novel iron-containing poly(ferrocenedimethano)cyclotriphosphazene synthesized via a facile polycondensation between 1,1'-ferrocenedimethanol and hexachlorocyclotriphosphazene. The morphology was tuned by introducing two sets of mixed solvent systems that are tetrahydrofuran:acetonitrile and acetone:toluene mixtures, for the growth of nanotubes and microspheres, respectively. A growth mechanism for nanotubes and microspheres has been proposed. The nanotubes exhibited intrinsic paramagnetic properties (saturation magnetization of 53 emu/g and coercivity of 19.6) and fluorescence emission (2450 au) as compared to microspheres owing to their remarkable cross-linked structure. Both nanotubes and microspheres demonstrated significant potential to absorb negatively charged hazardous methyl orange dye, and their adsorption capacities came out under the range of 880-2235 and 737-2125 mg g-1, respectively. This facile fabrication route is anticipated to open a new window for structural manipulation of other metal-containing polymers for improved physicochemical properties.

Preparation of Poly(bis(phenoxy)phosphazene) and 31P NMR Analysis of Its Structural Defects under Various Synthesis Conditions.

Poly(aryloxy)phosphazenes emerge as an important class of hybrid polymers for a whole range of potential applications. To date, however, little is known about the detailed reaction mechanisms during preparation. This draws a great deal of attention for developing well-defined and well-controllable synthesis methods. In this paper, poly(dichlorophosphazene) (PDCP) has been successfully synthesized, and subsequent reaction with sodium phenoxide or phenol in the presence of K2CO3 can produce poly(bis(phenoxy)phosphazene) (PBPP). To elucidate the issues of branching and cross-linking, focuses have been placed on the change of various reaction conditions, in terms of concentration, temperature, time, solvent, catalysis, etc. The product polymers were examined using the techniques of 31P and 13C NMR, GPC, XPS, and FT-IR, in order to characterize the structural defects, in particular, branching and unwanted substitutions, such as addition of water molecules or oxidation of the phosphorus atoms on the backbone of the polymers. This work sheds light on the tailor design of poly(aryloxy)phosphazenes and other polyphosphazenes with more uniform and controllable structures.

Burden of Diarrhea in the Eastern Mediterranean Region, 1990-2013: Findings from the Global Burden of Disease Study 2013.

Diarrheal diseases (DD) are leading causes of disease burden, death, and disability, especially in children in low-income settings. DD can also impact a child's potential livelihood through stunted physical growth, cognitive impairment, and other sequelae. As part of the Global Burden of Disease Study, we estimated DD burden, and the burden attributable to specific risk factors and particular etiologies, in the Eastern Mediterranean Region (EMR) between 1990 and 2013. For both sexes and all ages, we calculated disability-adjusted life years (DALYs), which are the sum of years of life lost and years lived with disability. We estimate that over 125,000 deaths (3.6% of total deaths) were due to DD in the EMR in 2013, with a greater burden of DD in low- and middle-income countries. Diarrhea deaths per 100,000 children under 5 years of age ranged from one (95% uncertainty interval [UI] = 0-1) in Bahrain and Oman to 471 (95% UI = 245-763) in Somalia. The pattern for diarrhea DALYs among those under 5 years of age closely followed that for diarrheal deaths. DALYs per 100,000 ranged from 739 (95% UI = 520-989) in Syria to 40,869 (95% UI = 21,540-65,823) in Somalia. Our results highlighted a highly inequitable burden of DD in EMR, mainly driven by the lack of access to proper resources such as water and sanitation. Our findings will guide preventive and treatment interventions which are based on evidence and which follow the ultimate goal of reducing the DD burden.

On Comparison of Series and Numerical Solutions for Flow of Eyring-Powell Fluid with Newtonian Heating And Internal Heat Generation/Absorption.

In this paper, we have investigated the combined effects of Newtonian heating and internal heat generation/absorption in the two-dimensional flow of Eyring-Powell fluid over a stretching surface. The governing non-linear analysis of partial differential equations is reduced into the ordinary differential equations using similarity transformations. The resulting problems are computed for both series and numerical solutions. Series solution is constructed using homotopy analysis method (HAM) whereas numerical solution is presented by two different techniques namely shooting method and bvp4c. A comparison of homotopy solution with numerical solution is also tabulated. Both solutions are found in an excellent agreement. Dimensionless velocity and temperature profiles are plotted and discussed for various emerging physical parameters.