Synergistic Processes Research Articles

A novel neutral-base coupling synergistic extraction system of Cyanex923 and primary amine N1923 for the recovery of cerium(IV) and fluorine from sulfuric acid medium

Cyanex923 (A) and primary amine N1923 (B) mixture was developed as a novel neutral-base coupling extraction system for the recovery of cerium(IV) (Ce(IV)) and fluorine (F−) from sulfuric acid (H2SO4) medium. This system demonstrated excellent synergistic effects for both Ce(IV) and F− extraction. In Ce(IV) solution, the maximal synergistic coefficient (Rmax) for Ce(IV) was 2.93 at the Cyanex923 mole fraction (X) of 0.6. In Ce(IV)-F− solution, the presence of F− enhanced the synergistic extraction of Ce(IV) with the Rmax-Ce(IV) of 4.39 at XCyanex923 = 0.6, meanwhile the synergistic coefficient for F− (Rmax-F−) reached 4.33. The synergistic extraction mechanisms were systematically studied through multiple techniques including stoichiometry analysis, FT-IR and NMR characterizations. Equilibrium structures of extracted complexes were determined as Ce(SO4)2∙(A)1.5(B) and CeF(SO4)1.5∙(A)(B). Thermodynamic investigations revealed that the synergistic extraction processes were spontaneous. Specifically, the extraction process for Ce(IV) was endothermic and entropy driven, while the extraction process for Ce(IV)-F− was exothermic and enthalpy driven. The extracted Ce(IV) and F− can be almost stripped completely using HNO3 with additive H2O2, and CeF3 particles were obtained by reductive stripping from Ce(IV)-F− loaded organic phase as confirmed by XRD, SEM and DLS. The Cyanex923-N1923 system achieved comprehensive recovery of Ce(IV) and F− from the Bayan Obo mixed RE H2SO4 liquor and this excellent synergistic extraction performance suggests its high practical application potential.

MiR-345-5p regulates adipogenesis via targeting VEGF-B.

Adipocyte differentiation involves a series of highly synergistic processes, including clone amplification, proliferation arrest, and terminal differentiation. However, the mechanisms that control these different steps remain unclear. Emerging studies support that miRNAs play an important role in regulating adipogenesis. In this study, we found that the expression of miR-345-5p decreased during adipogenic differentiation, and overexpression of miR-345-5p reduced lipid accumulation in adipocytes and the expression of adipocyte related genes essential to lipogenic transcription, fatty acid synthesis and fatty acid transport. In addition, miR-345-5p directly targeted the 3’UTR of vascular endothelial growth factor B, and miR-345-5p mimic inhibited the expression of vascular endothelial growth factor B at both mRNA and protein levels. In conclusion, our results demonstrate that miR-345-5p inhibits adipocyte differentiation via targeting vascular endothelial growth factor B.

Rural Migration and Urbanization in China: Historical Evolution and Coupling Pattern

Using a population dataset of China, this study analyzes the spatial pattern of rural migration and urbanization and their coupling coordination relationship and investigates the causes of their spatial heterogeneity. Results show that rural migration and urbanization from 1978 to 2017 can be divided into three stages, i.e., the recovery and development stage, the stable and rapid development stage, and the stage of promoting the citizenization of the rural migrant population. From 2000 to 2010, counties with average annual growth rates of the ratio of rural migration (GRM) ranging from 0 to 5.00% showed a spatial pattern of ubiquitous distribution, while there were significant spatial inequalities in the average annual growth rates of the urbanization rate of the residential population (GUR) and hukou-registered population (GUH). Since urbanization and rural migration are two synergistic processes, coupling coordination degrees (CCDs) between GRM and GRU as well as GRM and GUH were generally between 0.60 and 0.80. Due to the gaps in socioeconomic development, spatial distance, and the policy system, they also showed regional heterogeneity, and there were notable differences in CCD between rural migration and urbanization of residential and hukou-registered populations. Finally, we propose that China should implement targeted and people-oriented measures to guide rural migration, promote new-type urbanization, and achieve integrated urban–rural development.

Enhanced decolourization of methyl orange by immobilized TiO2/chitosan-montmorillonite.

Many attempts have been made to improve the photocatalytic performance of immobilized photocatalysts for large-scale applications by modification of the photocatalyst properties. In this work, immobilized bilayer photocatalyst composed of titanium dioxide (TiO2) and chitosan-montmorillonite (CS-MT) were prepared in a layer-by-layer arrangement supported on glass substrate. This arrangement allows a simultaneous occurrence of adsorption and photocatalysis processes of pollutants, whereby each layer could be independently modified and controlled to acquire the desired degree of occurring processes. It was found that the addition of MT clay within the CS composite sub-layer improved the mechanical strength of CS, reduced its swelling and shifted its absorption threshold to higher wavelengths. In addition, the band gap energy of the photocatalyst was also reduced to 2.93 eV. The immobilized TiO2/CS-MT exhibited methyl orange (MO) decolourization rate of 0.071 min-1 under light irradiation, which is better than the single TiO2 due to the synergistic processes of adsorption by CS-MT and photocatalysis by TiO2 layer. The MO dye took 6 h to achieve complete mineralization and produced sulfate and nitrate ions as the by-products. Furthermore, the immobilized TiO2/CS-MT could be reused for at least ten cycles of application without significant loss of its activity.

Bioavailability of Micronutrients From Nutrient-Dense Whole Foods: Zooming in on Dairy, Vegetables, and Fruits.

In order to fully exploit the nutrient density concept, thorough understanding of the biological activity of single nutrients in their interaction with other nutrients and food components from whole foods is important. This review provides a narrative overview of recent insights into nutrient bioavailability from complex foods in humans, highlighting synergistic and antagonistic processes among food components for two different food groups, i.e., dairy, and vegetables and fruits. For dairy, bioavailability of vitamins A, B2, B12 and K, calcium, phosphorous, magnesium, zinc and iodine are discussed, whereas bioavailability of pro-vitamin A, folate, vitamin C and K, potassium, calcium, magnesium and iron are discussed for vegetables and fruits. Although the bioavailability of some nutrients is fairly well-understood, for other nutrients the scientific understanding of uptake, absorption, and bioavailability in humans is still at a nascent stage. Understanding the absorption and bioavailability of nutrients from whole foods in interaction with food components that influence these processes will help to come to individual diet scores that better reflect absorbable nutrient intake in epidemiologic studies that relate dietary intake to health outcomes. Moreover, such knowledge may help in the design of foods, meals, and diets that aid in the supply of bioavailable nutrients to specific target groups.

Recent advances in homogeneous photocatalytic carboxylation incorporated with CO<sub>2</sub>

<p indent="0mm">Carbon dioxide (CO₂) has the advantages of low price, non-toxic, abundant and renewable. As CO₂ is an indispensable part of natural photosynthesis, it seems feasible to achieve artificial CO₂ fixation with the aid of light. For light-driven utilization of CO₂, two major categories can be diversified: (1) Photoreduction of CO₂ into other C1 resources, such as carbon monoxide, methanol, formic acid, and methane; (2) photocarboxylation, which is a green and sustainable method of fixing CO₂ into organic molecules. Therefore, taking CO₂ as a C1 synthon to participate in the reaction is an effective means to utilize it. Carrying out carboxylation reaction with CO₂ as raw material to produce acrylic acid, benzoic acid or other high value-added carboxylic acid derivatives has been a very important research significance. The carboxylation reactions using CO₂ usually include: (1) The use of strong nucleophiles such as Grignard reagents; (2) the use of stoichiometric metal reducing agents; (3) high temperature, high pressure and other conditions to activate the thermodynamic and dynamic stable CO₂. In the past decade, the homogeneous photocatalytic reaction has made a great progress. Researchers found photocatalytic organic reactions have many advantages, such as mild reaction conditions, high selectivity, and environmental protection. Compared to conventional thermal reaction system with CO₂ in the carboxylation reaction, the carboxylation reaction in photocatalysis has the following advantages: (1) Avoid the utilization of unstable strong reductant; (2) most of the reaction under mild conditions are performed; (3) during the reaction and post-processing to reduce the environmental impact. This article mainly introduces and summarizes the homogeneous carboxylation reactions involving photocatalytic CO₂ in recent years. At the same time, the study of mechanism is also an important part in the homogeneous photocatalytic reaction, especially in the field of the carboxylation reactions. The current photocatalytic carboxylation reaction can be roughly divided into three categories: (1) The electron transfer process occurs between the substrate and the photocatalyst, and the nucleophilic attack on the CO₂ molecule occurs after the formation of the corresponding anion intermediate to achieve carboxylation; (2) single electron transfer (SET) occurs between the CO₂ molecule and the photocatalyst, forming a CO₂ radical anion and then reaction with the substrates; (3) with assistant of the transition metal to form complex with the substrate and/or CO₂, a series of photocatalytic electron transfer processes and ligand transfer reactions to achieve the carboxylation. In addition, there is a carboxylation reaction realized by a synergistic [4+2] mechanism. Considering the importance of the study on the reaction mechanism in organic catalytic reactions, this article will focus on the employ the different types of intermediates generated in the reaction to achieve the homogeneous photocatalytic carboxylation of various substrates with CO₂, which include four types reaction mechanisms such as anionic intermediates, CO₂ radical anions, transition metal participation, and synergistic processes.

PHILOSOPHICAL ASPECTS OF ADAPTIVE MANAGEMENT OF SOCIAL AND PEDAGOGICAL SYSTEMS

Abstract. The article describes the deployment of market transformations in all spheres of the economy of Ukrainian society, including in education. This causes changes in human living conditions and requirements for its social formation and development, which is what is happening in the education system. The authors distinguish socio-pedagogical systems, which includes educational institutions and institutions at all levels of educational organization, from pre-school to postgraduate education.&#x0D; The article emphasizes that any socio-pedagogical system needs management, the requirements to which are similarly changed during the formation and development of a new the socio-economic structure of society. Management from authoritarian is gradually becoming really flexible, affiliate, adaptive. The practical use of new management requires consideration of its philosophical aspects, since it is linked to the involuntary restructuring of the ideological positions of the executives.&#x0D; Transformation processes are the subject of research on domestic and foreign scientists.&#x0D; Analytical review of literary sources, as noted by the authors, testifies to the study of issues on changing the world outlook of the person, modernization of the educational process in educational institutions, development of synergetic principles of management, etc. The issues of the emergence and affirmation of reflective control as a kind of adaptive control are highlighted separately. In Ukraine, there is a School of Adaptive Management of Social and Pedagogical Systems, whose representatives disseminate knowledge and experience of using content, forms, and technologies of a new type of management activity in educational practice. In general, research on this topic is diverse and conducted at the intersection of different sciences, technology, pedagogy, psychology, and inter-scientific relations. However, the authors identify a lack of research on the philosophical aspect of adaptive management.&#x0D; Usually, the philosophical foundations of management in the traditional system was the philosophy of determinism, which is characterized by the causal conditionality of phenomena / processes. The development of the information society and market relations have brought to life the synergistic processes that occur under conditions of instability and accompany the self-organization of complex systems.&#x0D; The authors distinguish from the synergetic position four stages of self-development: destabilization - the result: swaying ties; orientation - result: orientation to a certain direction of development; organizational - result: self-structuring, the appearance of neoplasm; productive -result: qualitative and quantitative changes, self-development.&#x0D; The article provides a comparative analysis of the philosophical and functional basis of traditional and adaptive management. The authors conclude that the philosophical basis of adaptive management is the theory of instability, which explains the nonlinear development. Finally, the direction of further research is identified.

Physical Activity Reduces the Risk of Recurrence and Mortality in Cancer Patients.

The biological mechanisms through which physical activity reduces metastatic disease recurrence and mortality in cancer patients are not known. This review offers the hypothesis that physical activity reduces the risk of recurrence and mortality in cancer patients through two synergistic processes: 1) indirect (systemic) effects related to the host tumor microenvironment; and 2) direct (physical) effects on cancer cells.

Exploring bacterial pathogen community dynamics in freshwater beach sediments: A tale of two lakes.

Pathogenic bacteria associated with freshwater ecosystems can pose significant health risks particularly where recreational water use is popular. Common water quality assessments involve quantifying indicator Escherichia coli within the water column but neglect to consider physical and geochemical factors and contributions from the sediment. In this study, we used high-throughput sequencing to investigate sediment microbial communities at four freshwater public beaches in southern Ontario, Canada and analysed community structure, function, and gene expression with relation to geographical characteristics. Our results indicate that beach sediments at the sediment-water interface could serve as potential sources of bacterial contamination under low-energy environments with tightly packed small sediment particles compared with high-energy environments. Further, the absence of pathogens but expression of pathogenic transcripts suggests occurrence of alternate gene acquisition. Pathogenicity at these locations included expression of Salmonella virulence factors, genes involved in pertussis, and antimicrobial resistance. Finally, we introduce a proposed universal bacterial pathogen model to consider the combined and synergistic processes used by these microbes. To our knowledge, this is the first study of its kind to investigate chemolithotrophic activity related to pathogens within bed sediment at freshwater beaches. This work helps advance current understanding of health risks in these environments.

Gold nanoclusters-poly(9,9-dioctylfluorenyl-2,7-diyl) dots@zeolitic imidazolate framework-8 (ZIF-8) nanohybrid based probe for ratiometric analysis of dopamine

Ratiometric analysis of dopamine (DA) in complex biological system is urgently desired. In this work, a novel dual-emission fluorescence probe was fabricated by embedding both gold nanoclusters (AuNCs) and poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) dots into zeolitic imidazolate framework-8 (ZIF-8) (abbreviated as ZIF-8@AuNCs-PFO) and applied to ratiometric analysis of DA. Remarkably, encapsulating AuNCs and PFO dots into ZIF-8 not only achieved an excellent aggregation induced emission (AIE) enhancement effect on AuNCs (5 times increase), but also brought about an unique DA-triggered asynchronous fluorescence changes of AuNCs and PFO dots. The as-prepared probe exhibited excellent performance toward DA in the concentrations range from 0.01 to 10000 μmol L−1 and good selectivity over interfering substances. The detection limit of DA was as low as 4.8 nmol L−1. Furthermore, good stability and practicability of the probe in human serum samples suggesting its great potential for diagnostic purposes. Moreover, the quenching mechanism of AuNCs was intensively studied and summarized as three synergistic processes: (i) electron transfer between AuNCs and DA; (ii) DA-triggered architecture change of ZIF-8; (iii) fluorescence resonance energy transfer (FRET) between AuNCs and polydopamine (PDA), which offered an important theory for ZIF-based fluorescent probes.

Social and economic urbanization processes in communes in a metropolitan area

The article discusses selected social and economic changes taking place in the communes of a metropolitan area following a political transformation period in Poland, Central and Eastern Europe. Dynamic urbanization of communes of Polish metropolitan areas was one of the numerous results of socio-economic transformation of the country after 1989. The process played an important part in shaping both functional-spatial systems and awareness of self-governmental authorities and local communities in terms of the values of development of integrated systems of the technical infrastructure. Rapid changes taking place during the first years of the social and economic transformation caused a few negative functional-spatial phenomena in the communes bordering the central city. The analysis covered processes taking place in the communes that constitute a considerable part of the Poznań Metropolitan Area. Monitoring processes which promote increased electricity demand (of both social and economic nature, including migration and increase in the number of economic operators in years 2000-2018) taking place in areas of the communes within the impact area of the central city may enable selfgovernments to implement sustainable development rules and facilitate both controlled urbanization of communes of Polish metropolitan areas and correct sustainable development of the technical infrastructure. The example of the analysed selected economic and social issues concerning transformations of communes within the impact zone of the central city shows that the transformation process in the metropolitan areas in Poland after the political change occurs at different levels and to varying degrees. As a result, the new situation rendered it necessary to connect developing economic functions, urban in character, with the traditional functions of agricultural production space. However, expansion of the central city caused a lot of rural communes to lose their primary agricultural character. Combination of housing and economic functions along with traces of agricultural functions, development of technical infrastructure, and transportation network for cars and passengers caused qualitative and quantitative changes in areas of communes adjacent to the central city. The functional-spatial changes and socioeconomic transformation in Poland began a dynamic urbanization process of areas of rural communes bordering the central city. All the processes facilitated synergy in the transformation of communes. A variable pace and scale of the ongoing ecological, economic and social phenomena require constant monitoring both by architects and urban planners, both in practice and theory to examine synergistic processes occurring in contemporary urbanization in the rural areas. Self-governments and local communities, who share responsibility for functional-spatial planning and management of the communes in a metropolitan area, should modify tendencies of sustainable functional-spatial and socio-economic development. The need to design and realize new buildings with the diverse functions in rural communes activates their further development. Finally, this need stimulates synergistic processes occurring in functional-spatial and socioeconomic development in communes of a metropolitan area.

Amphoteric starch-based bicomponent modified soil for mitigation of harmful algal blooms (HABs) with broad salinity tolerance: Flocculation, algal regrowth, and ecological safety

The treatment of harmful algal blooms (HABs) by in-situ flocculation is an emerging technology capable of efficiently removing HABs from natural waters. However, differences in salinity, pH and algal species in freshwaters and seawaters can influence the flocculation treatment. In this study, we developed a bicomponent modified soil using amphoteric starch (AS) and poly-aluminium chloride (PAC) in order to effectively flocculate microalgae under broad salinity conditions. Specifically, the impacts of water salinity (0–3.3%), pH (3–11), and algal species (Microcystis aeruginosa and marine Chlorella sp.) were investigated in order to evaluate efficiency, dosage and mechanisms of algae flocculation. The results showed that AS-PAC modified soils possessed excellent resistance to salinity change due to the anti-polyelectrolyte effect of AS, which contributed to 99.9% removal efficiency of M. aeruginosa in fresh and saline waters, and Chlorella sp. in marine water, respectively. The dosage of the flocculant modifier was only 10–20% of that of another proven modifier (i.e. Moringa oleifera), which substantially reduced the material cost. The high salinity tolerance of algal flocculation by the AS-PAC modified soil was attributed to the synergistic processes of charge neutralization and netting-bridging. Thus, this study has developed a universal flocculant and revealed fundamental mechanisms for the mitigation of HABs under broad salinity conditions.

Ion tracks formation through synergistic energy processes in strontium titanate under swift heavy ion irradiation: Experimental and theoretical approaches

The primary motivation for studying ion-solid interactions and the responses of various materials to energetic irradiation is the fundamental necessity and importance to get a deeper understanding of how irradiation changes the lattice structures and physico-chemical properties of solid materials. Under the action of extreme electronic energy deposition induced by swift Kr17+, Ar12+ and Ni19+ irradiation, the formation mechanism of latent tracks with different damage morphologies in pristine and predamaged SrTiO3 crystals are analyzed utilizing experimental characterizations of the lattice damage and numerical calculations from the inelastic thermal spike model. In contrast to Ar12+ and Ni19+ irradiation, Kr17+ irradiation, with an ion energy of 2.35 MeV/u and electronic energy loss of 16.7 keV/nm, increased the lattice temperature of the pristine crystal to 3500 K, and via a subsequent rapid quenching process, discontinuous tracks including individual spherical defects and discontinuous cylindrical damaged zones were formed. The related damage morphology demonstrates the threshold value of the lattice-temperature change induced by irradiation for track production in pristine SrTiO3, which is fundamental and essential for comparing irradiating-ion velocities and electronic energy losses. Owing to the decrease in thermal conductivities and increase in electron-phonon coupling in Au+-irradiation-damaged SrTiO3, subsequent Si3+, Ar12+ and Kr17+ irradiation significantly increased the lattice temperature of predamaged crystals to greater than 3500 K, leading to discontinuous and continuous track production in the predamaged crystals. Thus, the pre-existing damage produced by nuclear energy loss interacted synergistically with the electronic energy loss and effectively enhanced the lattice-temperature increase and promoted track formation.

Synergistic adsorption-photocatalysis processes of graphitic carbon nitrate (g-C3N4) for contaminant removal: Kinetics, models, and mechanisms

The synergy between adsorption and photocatalysis has been well recognized in contaminant photodegradation; however, the governing mechanism is still not clear. The main objective of this work is to understand the kinetic processes of synergic adsorption-photocatalysis of graphitic carbon nitrate (g-C3N4), a visible light responsive photocatalyst with a planar graphitic-like structure, in organic contaminant removal. An anionic dye Reactive Red 120 (RR120), which has six sulphonate groups and a complex aromatic molecular structure, was selected as a model contaminant compound. A range of experiments were conducted to determine the kinetics of adsorption, photodegradation, and the integrated process. Various kinetic models were used to simulate and interpret the experimental data and thus to unveil the governing mechanisms. The integrated adsorption and photodegradation of the dye by g-C3N4 was mainly controlled by: 1) adsorption of dye onto g-C3N4 surface, 2) photodegradation of dye in bulk solution, and 3) photodegradation of adsorbed dye on g-C3N4 surface. Both experimental and modeling results showed that the adsorption kinetic rate (3.37 min−1) was faster than the photodegradation kinetic rates. In addition, the surface photodegradation kinetic rate of adsorbed dye (0.149 min−1) was faster than that in solution (0.005 min−1). Adsorption process thus can promote the photodegradation of contaminants by g-C3N4. On the other hand, photodegradation of dye-laden g-C3N4 regenerated its adsorption capacity for multiple times, suggesting photocatalysis process can also promote the adsorption of contaminates on g-C3N4.

Comparative study of persulfate oxidants promoted photocatalytic fuel cell performance: Simultaneous dye removal and electricity generation

Introducing peroxymonosulfate (PMS) and peroxydisulfate (PDS) into the photocatalytic fuel cell (PFC) system were investigated by comparing the Reactive Brilliant Blue (KN-R) degradation and synchronous electricity production. The two persulfates (PS) themselves are strong oxidant, and could be activated and as electron sacrificial agent in the PFCs, facilitating the photoelectrocatalysis and expanding redox to the entire cell space. Hence, the two established PFC/PS systems manifested prominent cell performances, enhancing the KN-R decomposition and electric power production relative to the virgin PFC. Thereinto, the KN-R removal rate of PFC/PMS was faster than that of PFC/PDS, but an opposite trend appeared in the electricity generation. Besides, the cell performances of the two cooperative systems were evaluated at different operation conditions, including PS dosage, solution pH, and irradiation strength. Moreover, the dye elimination principle was explored by radicals scavenging experiment, and the consequence revealed that hydroxyl radical (HO•), sulfate radical (SO4•ˉ) and singlet oxygen were chief active species in the PFC/PMS, and HO•, SO4•ˉ and superoxide anion played the key roles in the PFC/PDS. Furthermore, the calculated economic indicator demonstrated that the economy of the two synergistic processes were greater than that of UV/PS and solo PFC, and the PFC/PDS was more cost-effective than PFC/PMS.

Aging in skin of color

Ethnic skin is quickly emerging as the norm in the United States, and as the population becomes more diverse, there is also a projected rise in the number of aging adults. Given the paucity of data regarding aging in ethnic skin, the authors have consolidated available information for this population. Literature examining structural and functional variation of aging in ethnic skin types was primarily found through PubMed and supplemental textbook chapters. Aging is comprised of two synergistic processes, intrinsic or chronologic aging, and extrinsic aging. Caucasian, African American, East Asian, and Hispanic skin each have distinguishing features of aging, but all populations share dyspigmentation, rhytides, and skin laxity. Increased melanin content predisposes skin of color to a greater degree of hyperpigmentation, but skin thickness may protect against the formation of rhytides. Tailored prevention and treatment are also paramount in attaining favorable outcomes for this growing cohort.

Synergistic effects on the co-combustion of medicinal biowastes with coals of different ranks

In attempt to understand the synergistic mechanisms controlling the co-combustion processes of blended fuels, two medicinal biowastes (lignocellulose and non-lignocellulose) and three different-rank coals (lignite, bituminite and anthracite) were employed in this work. Intrinsic characteristics of parent materials were firstly measured with the help of 13C NMR, FTIR and XRD technologies, followed by the thermogravimetric analysis of mono- and co-combustion behaviors. The results suggested that synergistic processes depended on the amount and properties of light volatiles in biowastes, but both lignocellulose and non-lignocellulose biowastes had positive effects on co-combustion with coals to some extent. Among them, the blends with low-rank coal showed the highest combustion efficiency. The actual HHV of blends with coal A (low-rank coal) exceeded their theoretical one, reaching the increases of 3.1–4.5%, 6.9–7.0% and 11.5–11.6% for 30%, 50% and 70% addition of coal A, respectively. Additionally, the introduction of biowastes also lowered the activation energy to initiate main decomposition of coals, increased the co-combustion reactivity, as well as altered the main combustion profiles to different extends. In general, co-combustion with low-rank coal achieved the best combustion efficiency among the blends. These findings would be beneficial for efficient utilization of organic biowastes as solid fuels in existing co-firing equipment.

Dual Gold/Silver Catalysis Involving Alkynylgold(III) Intermediates Formed by Oxidative Addition and Silver-Catalyzed C-H Activation for the Direct Alkynylation of Cyclopropenes.

While gold-mediated synergistic catalytic processes involving transmetalations with other metals are well understood, AuI /AuIII cycles in these reactions are rarely reported. Herein a gold-catalyzed direct alkynylation of cyclopropenes is enabled by two operating catalytic cycles, an oxidative catalytic cycle involving an alkynyl AuIII complex formed by oxidative addition and one involving a silver-mediated C-H activation.

Role of hubs in the synergistic spread of behavior.

The spread of behavior in a society has two major features: the synergy of multiple spreaders and the dominance of hubs. While strong synergy is known to induce mixed-order transitions (MOTs) at percolation, the effects of hubs on the phenomena are yet to be clarified. By analytically solving the generalized epidemic process on random scale-free networks with the power-law degree distribution , we clarify how the dominance of hubs in social networks affects the conditions for MOTs. Our results show that, for , an abundance of hubs drive MOTs, even if a synergistic spreading event requires an arbitrarily large number of adjacent spreaders. In particular, for , we find that a global cascade is possible even when only synergistic spreading events are allowed. These transition properties are substantially different from those of cooperative contagions, which are another class of synergistic cascading processes exhibiting MOTs.

Effects of montmorillonite on the enhancement of physicochemical, optical and photocatalytic properties of TiO2/chitosan bilayer photocatalyst

Chitosan-montmorillonite (CS-MT) composites of different MT composition were prepared in 5% of acetic acid solution and fabricated on glass plates. The composite film was then combined with TiO2 in an immobilized layer-layer manner for removing methyl orange dye via synergistic photocatalytic-adsorption processes. The effects of MT addition to the CS matrix were investigated with respect to the physicochemical and optical properties. The presence of MT within the composite reduced the swelling and improved the adhesiveness as well as the thermal stability of CS. The MT clay assisted in producing higher hydroxyl radicals and improving the solid-state oxidation of CS within the adsorbent sub-layer for the photocatalytic enhancement of TiO2/CS-MT than its counterpart TiO2/CS. Subsequently, the photocatalytic activity of the TiO2/CS-MT was 1.3 and 4.2-times better than the TiO2/CS and TiO2 photocatalysts, respectively. This TiO2/CS-MT photocatalyst was also reusable for at least ten cycles of application.