Search

CH 4 @C 60 was the first example within which an organic molecule has been embedded in C 60 . CH 4 can rotate freely in the molecular cage, and the carbon skeleton structure of the C 60 has no obvious deformation. The electronic structure of CH 4 @C 60 and interaction between C 60 and CH 4 were studied under quantum mechanical calculation method. The different reaction sites on C-C bonds in C 60 and the weak Van der Waals interaction between CH 4 and C 60 were shown clearly. These results and the orbital interaction between CH 4 and C 60 were helpful for understanding and further application of this unique biggest organic molecule CH 4 contained in C 60 structure so far., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Sustainable water desalination and purification membrane processes require new practical pathways to improve their efficiency. To this end, the inclusion of two-dimensional materials in membrane structure has proven to have a significant impact in various applications. In particular, in processes such as membrane distillation and crystallization, these materials, thanks to their characteristics, help to increase the recovery of clean water and, at the same time, to improve the quality and the production of the recovered salts. Therefore, a fundamental aspect of obtaining 2D materials with certain characteristics is the technique used for the preparation. This review provides a broad discussion on the preparation and proprieties of 2D materials, including examples of organic structures (such as graphene and structures containing transition metals and organic metals). Finally, the critical challenges, future research directions, and the opportunities for developing advanced membranes based on 2D materials are outlined. [ABSTRACT FROM AUTHOR]

Efficient graphene production is critical for commercial applications. Liquid-phase exfoliation, one of the most promising methods for mass production of graphene, is limited by small size and low yield. By optimizing the fluid forces, we have achieved the size-controlled production of high-quality graphene. The bending and cleavage caused by the collision promote cavitation and shear exfoliation. High-aspect-ratio graphene has an average area of ~ 1.5μm2 and a thickness of ~ 1.5 nm. Simultaneously, the dispersion concentration of small size graphene (average area ~ 0.6μm2) is 0.17 mg mL−1, while the yield and efficiency reach 30% and 15%·h−1, respectively, through recycling sediment (initial concentration: 1 mg mL−1). Furthermore, the binary solvent of isopropanol and water is eco-friendly, low boiling, cost-effective. Jet collision can also be applied for exfoliation of other two-dimensional materials such as h-BN. This finding is essential for optimizing the design of liquid-phase exfoliation devices to obtain appropriate size and yield. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) have emerged as promising materials for organic electronics, including organic photovoltaics (OPVs), organic field-effect transistors (OFETs), and organic light-emitting diodes (OLEDs). Particularly, non-hexagonal ring-fused PAHs are highly desirable due to their unique optoelectronic properties. Herein, a new redox-active azulene-perylene diimide triad 1 and its ring-fused counterpart, diazulenocoronene diimide 2, were synthesized and fully characterized by a combination of NMR, cyclic voltammetry, and UV-visible absorption spectroscopy. Direct comparison of their electronic properties leads us to the conclusion that a significant change in the localization of HOMO and LUMO occurs upon the fusion of azulene and perylene diimide in 2, leading to the lack of intramolecular charge-transfer character for transitions in the visible spectral region. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed to gain further insight into various electronic transitions. Moreover, we found that the adaptive response to acids and bases manifests itself in a reversible two-color change that can be attributed to changes in the chemical structures. Our findings pave the way for manipulating the relative HOMO and LUMO energy levels of organic chromophores by fusing non-alternant azulenes to an otherwise flat PAH, which could possibly lead to applications in organic electronics and optical sensors. [ABSTRACT FROM AUTHOR]

Hydrogen is a promising green fuel carrier that can replace fossil fuels; however, its storage is still a challenge. Carbon-based materials with metal catalysts have recently been the focus of research for solid-state hydrogen storage due to their efficacy and low cost. Here, we report on the exfoliation of expanded graphite (EG) through high shear mixing and probe tip sonication methods to form graphene-based nanomaterial ShEG and sEG, respectively. The exfoliation processes were optimized based on electrochemical capacitance measurements. The exfoliated EG was further functionalized with palladium nanoparticles (Pd-NP) for solid-state hydrogen storage. The prepared graphene-based nanomaterials (ShEG and sEG) and the nanocomposites (Pd-ShEG and Pd-sEG) were characterized with various traditional techniques (e.g., SEM, TEM, EDX, XPS, Raman, XRD) and the advanced high-resolution pair distribution function (HRPDF) analysis. Electrochemical hydrogen uptake and release (QH) were measured, showing that the sEG decorated with Pd-NP (Pd-sEG, 31.05 mC cm−2) and ShEG with Pd-NP (Pd-ShEG, 24.54 mC cm−2) had a notable improvement over Pd-NP (9.87 mC cm−2) and the composite of Pd-EG (14.7 mC cm−2). QH showed a strong linear relationship with an effective surface area to volume ratio, indicating nanoparticle size as a determining factor for hydrogen uptake and release. This work is a promising step toward the design of the high-performance solid-state hydrogen storage devices through mechanical exfoliation of the substrate EG to control nanoparticle size and dispersion. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) is evolving in various sectors such as industries, healthcare, smart homes, and societies. Billions and trillions of IoT devices are used in e-health systems, known as the Internet of Medical Things (IoMT), to improve communication processes in the network. Scientists and researchers have proposed various methods and schemes to ensure automatic monitoring, communication, diagnosis, and even operating on patients at a distance. Several researchers have proposed security schemes and approaches to identify the legitimacy of intelligent systems involved in maintaining records in the network. However, existing schemes have their own performance issues, including delay, storage efficiency, costs, and others. This paper proposes trusted schemes that combine mean and subjective logic aggregation methods to compute the trust of each communicating device in the network. Additionally, the network maintains a blockchain of legitimate devices to oversee the trusted devices in the network. The proposed mechanism is further verified and analyzed using various security metrics, such as reliability, trust, delay, beliefs, and disbeliefs, in comparison to existing schemes. [ABSTRACT FROM AUTHOR]

Two-dimensional nanomaterials (2D NMs), consisting of atoms or a near-atomic thickness with infinite transverse dimensions, possess unique structures, excellent physical properties, and tunable surface chemistry. They exhibit significant potential for development in the fields of sensing, renewable energy, and catalysis. This paper presents a comprehensive overview of the latest research findings on the preparation and application of 2D NMs. First, the article introduces the common synthesis methods of 2D NMs from both "top-down" and "bottom-up" perspectives, including mechanical exfoliation, ultrasonic-assisted liquid-phase exfoliation, ion intercalation, chemical vapor deposition, and hydrothermal techniques. In terms of the applications of 2D NMs, this study focuses on their potential in gas sensing, lithium-ion batteries, photodetection, electromagnetic wave absorption, photocatalysis, and electrocatalysis. Additionally, based on existing research, the article looks forward to the future development trends and possible challenges of 2D NMs. The significance of this work lies in its systematic summary of the recent advancements in the preparation methods and applications of 2D NMs. [ABSTRACT FROM AUTHOR]

Carbon nanotube field-effect transistor (CNT-FET) based sensor devices are widely used in sensing applications of biomolecules in high sensitivity. In addition, covalent functionalization process can increase the interaction between the CNTs and biological molecules. In this article, we present the effect of boronic acid functionalization on the electrical properties of the CNT-FET due to boronic acid and its derivatives have been widely used for the glucose recognition. For this purpose, CNT-FET transistors were fabricated on SiO2/Si substrates utilising high purity semiconducting nanotubes as the channel layer and functionalized with pyrene-1-boronic acid. It was found that boronic acid functionalization causes a variation in electrical parameters of CNT-FET transistors such as conductance, transconductance, threshold voltage, field effect mobility, resistance, hysteresis gap, and charge transfer of carriers per unit length. The results show that pyrene-1-boronic acid treatment was observed to have a significant beneficial effect on the electrical properties of the CNT-FET and pyrene-1-boronic acid functionalized CNT-FET sensor devices may have great potential for glucose sensing applications. [ABSTRACT FROM AUTHOR]

The Internet of Medical Things (IoMT) has risen significantly in recent years and has provided better quality of life by enabling IoMT-based health monitoring systems. Despite that fact, innovative security mechanisms are required to meet the security concerns of such systems effectively and efficiently. Additionally, the industry and the research community have anticipated that blockchain technology will be a disruptive technology that will be able to be integrated into innovative security solutions for IoMT networks since it has the potential to play a big role in: (a) enabling secure data transmission, (b) ensuring IoMT device security, and (c) enabling tamper-proof data storage. Therefore, the purpose of this research work is to design a novel lightweight blockchain-based security architecture for IoMT-based health monitoring systems leveraging the features of the Hyperledger Fabric (HF) Platform, its utilities. and its lightweight blockchain nature in order to: (i) ensure entity authentication, (ii) ensure data confidentiality, and (iii) enable a more energy-efficient blockchain-based security architecture for IoMT-based health monitoring systems while considering the limited resources of IoMT gateways. While security mechanisms for IoT utilizing HF do exist, to the best of our knowledge there is no specific HF-based architecture for IoMT-based health monitoring systems. [ABSTRACT FROM AUTHOR]

Liquid phase exfoliation (LPE) has emerged as a promising method for the industrial-scale production of graphene. However, one of its critical steps, namely sonication, has faced challenges due to high power consumption and low efficiency, leading to limited applicability in industrial settings. This study introduces a novel, cost-effective microfluidic sonication device designed to significantly reduce power consumption while efficiently assisting the LPE process for graphene production. By coupling a capillary with a buzzer and applying an appropriate electric signal, simulation and particle tracing experiments reveal the generation of robust shear forces resulting from acoustic streaming and cavitation when the capillary end is immersed in the liquid. For the first time, the capillary-based sonication device was effectively utilized for graphene exfoliation in a DMF (N,N-Dimethylformamide) + NaOH liquid phase system. The SEM (Scanning Electron Microscope) and Raman characterization results corroborate the successful exfoliation of 100 nm with thicknesses below 10 nm graphene sheets from graphite flakes using this pioneering device. The values of I 2 D / I G increase after processing, which suggests the exfoliation of graphite flakes into thinner graphene sheets. The vibration-based acoustofluidic effector represents a versatile and scalable miniature device, capable of being employed individually for small-batch production, thereby optimizing the utilization of raw 2D materials, particularly in experimental scenarios. Alternatively, it holds the potential for large-scale manufacturing through extensive parallelization, offering distinct advantages in terms of cost-efficiency and minimal power consumption. [ABSTRACT FROM AUTHOR]

The free surface condition of water-entry problems will be significantly modified by the presence of an ice sheet on the water surface. In this paper, we employ computational fluid dynamics to simulate the process of a cylinder entering a water body vertically and validate the numerical method by comparing the cavity evolution with experimental data. Four high-speed water-entry cases are considered: an ice-free water surface, an ice sheet with circular holes, and an ice sheet with minor and normal sized petal-shaped holes. The cavity evolution, flow field characteristics, and motion parameters of the projectile after entering the water are analyzed separately, and the effects of the ice sheets with holes on the typical water-entry characteristics are identified. The results show that the cavity closure mechanism shifts from surface to shallow closure, and a funnel-shaped cavity is observed below the surface when ice is present. The size of the cavity is extremely restricted, but the collapse of the cavity is delayed. The pressure and flow characteristics around the projectile are also affected by ice on the water surface, and the stability of the trajectory is enhanced by the existence of the ice sheet. Finally, the positive acceleration of the projectile triggered by high pressure at the tail of the structure is found to be much larger than that in the ice-free case. [ABSTRACT FROM AUTHOR]

The discharge of emerging pollutants in the industrial process poses a severe threat to the ecological environment and human health. Photocatalytic self-Fenton technology combines the advantages of photocatalysis and Fenton oxidation technology through the in situ generation of hydrogen peroxide (H2O2) and interaction with iron (Fe) ions to generate a large number of strong reactive oxygen species (ROS) to effectively degrade pollutants in the environment. Graphite carbon nitride (g-C3N4) is considered as the most potential photocatalytic oxygen reduction reaction (ORR) photocatalyst for H2O2 production due to its excellent chemical/thermal stability, unique electronic structure, easy manufacturing, and moderate band gap (2.70 eV). Hence, in this review, we briefly introduce the advantages of the photocatalytic self-Fenton and its degradation mechanisms. In addition, the modification strategy of the g-C3N4-based photocatalytic self-Fenton system and related applications in environmental remediation are fully discussed and summarized in detail. Finally, the prospects and challenges of the g-C3N4-based photocatalytic self-Fenton system are discussed. We believe that this review can promote the construction of novel and efficient photocatalytic self-Fenton systems as well as further application in environmental remediation and other research fields. [ABSTRACT FROM AUTHOR]

The Hildebrand solubility parameter has been applied in several areas of science and engineering, assuming a relevant role in new scientific developments and practical applications in industry. This review shows its importance and relationship with development of research in flow assurance activities, especially involving heavy fractions of oils such as asphaltenes, resins and wax. The examples described illustrate its relevance and scope in the approaches of interest of flow assurance. They also show that it is a versatile property for many new applications, including the development of methodologies to obtain more reliable values for the various petroleum fluids and theoretical developments for its estimation in a wide range of temperature and pressure. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The experimental investigation of rare‐earth metal‐metal bonds remains a challenge in the study of chemical bonds. Herein, we report the synthesis and characterization of a novel heteronuclear di‐metallofullerene, ScY@C3v(8)‐C82, which contains a mixed rare‐earth metal‐metal bond. ScY@C3v(8)‐C82 was successfully synthesized by arc‐discharging method and characterized by mass spectrometry, UV‐vis‐NIR spectroscopy and single‐crystal X‐ray diffraction crystallography, which unambiguously determined its molecular structure. Theoretical calculations were also performed to study the optimized positions of Sc‐Y metallic dimer and the electronic configuration. The combined experimental and theoretical results confirmed that both Sc and Y atoms transfer two electrons to the C3v(8)‐C82 cage, i.e., (ScY)4+@(C3v(8)‐C82)4–. In particular, a covalent Sc‐Y σ2 bond, which has never been reported before, is proven to be formed inside C3v(8)‐C82 fullerene cage. This work presents a novel di‐metallofullerene containing mixed rare‐earth metal‐metal bond and expands the understanding of metal‐metal bonding of rare earth elements. [ABSTRACT FROM AUTHOR]

The central collision between a neon atom and a dodecahedrane cage has been investigated within the framework of ab initio Hartree-Fock molecular dynamics simulations for various initial velocities of the incident atom. Four scenarios regarding the interaction's outcome have been identified. A reaction channel involving the encapsulation of the projectile inside the molecular cage has been studied for a simulation time of 4.8 ps. The analysis is focused on: the rate of energy exchange between Ne and C20H20, the mechanical oscillation frequencies of the atom and the cage, and also, on the frequency with which the dipole moment changes. The results suggest that inside the molecular cage, neon is a stable atomic vibrator, which oscillates with the highest peak frequency of 16 THz. Furthermore, the same frequency characterizes the dipole moment oscillation, suggesting a strong coupling between the atom and the cage, making the endohedral system suitable for a wide range of applications in nano-electronics. [ABSTRACT FROM AUTHOR]

A considerable potential advantage of manufacturing electric and thermoelectric devices using endohedral metallofullerenes (EMFs) is their ability to accommodate metallic moieties inside their cavities. Published experimental and theoretical works have explained the usefulness of this resilience feature for improving the electrical conductance and thermopower. Through thorough theoretical investigations of three EMF complexes employing three different metallic moieties involving Sc3C2, Sc3N, and Er3N and their configurations on a gold (111) surface, this research demonstrates that the thermoelectric properties of these molecular complexes can be tuned by taking advantage of the charge transfer from metallic moieties to Ih-C80 cages. Mulliken, Hirshfeld, and Voronoi simulations articulate that the charge migrates from metallic moieties to cages; however, the amount of the transferred charge depends on the nature of the moiety within the complex. [ABSTRACT FROM AUTHOR]

This review emphasized structure and features of high performance covalently linked polymer/fullerene nanocomposite. The polymer grafting on fullerene molecules may usually occur through covalent bonding. The covalently linked nanocomposites improved fullerene dispersion and matrix-nanofiller interactions. Fullerene molecules have been grafted to conducting polymers (polyaniline, polythiophene, polythiophene derivatives, etc.) and thermoplastic/thermosetting polymers/block copolymers. The covalent grafting of polymer chains on fullerene molecules may lead to exceptional structural, morphological, electrical, thermal, and other physical properties. Development of unique star-shape/dendritic polymer/fullerene assemblies was also observed. The covalently interconnected polymer/fullerene nanocomposite possess remarkable physical contour for high-tech applications including solar cells, optical sensors, supercapacitors, and biomedical fields. [ABSTRACT FROM AUTHOR]

The encapsulation of He inside C20H20 cage has been investigated in the framework of molecular dynamics for incident atom energy in a range close to the threshold value, corresponding to the projectile passing through the pentagonal carbon ring. The entrance of He atom into dodecahedrane is analyzed in terms of static and dynamic potential barriers. The details of helium capture inside the molecular box is revealed by using geometric and energetic parameters, being associ- ated with the response of the atomic configuration near the collision site on the C20H20 cage. The energy transferred from the incident atom to deformation, vibrations, and recoil of the molecule target, was calculated as a function of the distance between the projectile and the collision site on C20H20 cage. The calculations show that the noble gas atom, encapsulated at the threshold of 315.62Å/ps, oscillates across the void of the dodecahedrane with frequencies of 2.5, 22.5, and 25.0 THz, monitored for a time interval of 10 ps starting at helium penetration into C20H20. Molecular dynamics calculations are based on ab-initio Hartree-Fock method, considering an adiabatic process. This study reveals advantageous features of helium encapsulation in dodecahedrane molecules in designing super-molecular structures for advanced nano sensors in the field of THz detectors. [ABSTRACT FROM AUTHOR]

New possibilities for the development of biosensors that are ready to be implemented in the field have emerged thanks to the recent progress of functional nanomaterials and the careful engineering of nanostructures. Two-dimensional (2D) nanomaterials have exceptional physical, chemical, highly anisotropic, chemically active, and mechanical capabilities due to their ultra-thin structures. The diversity of the high surface area, layered topologies, and porosity found in 2D nanomaterials makes them amenable to being engineered with surface characteristics that make it possible for targeted identification. By integrating the distinctive features of several varieties of nanostructures and employing them as scaffolds for bimolecular assemblies, biosensing platforms with improved reliability, selectivity, and sensitivity for the identification of a plethora of analytes can be developed. In this review, we compile a number of approaches to using 2D nanomaterials for biomolecule detection. Subsequently, we summarize the advantages and disadvantages of using 2D nanomaterials in biosensing. Finally, both the opportunities and the challenges that exist within this potentially fruitful subject are discussed. This review will assist readers in understanding the synthesis of 2D nanomaterials, their alteration by enzymes and composite materials, and the implementation of 2D material-based biosensors for efficient bioanalysis and disease diagnosis. [ABSTRACT FROM AUTHOR]

Fullerenes have been long investigated for application as singlet oxygen sources. Even though they possess high photosensitizing efficiency, their practical use is still limited, mostly because of insufficient absorption of visible and/or near-infrared light. This limitation can be overcome by introducing organic chromophores that absorb longer-wavelength light, either by covalent attachment to C60 or by its encapsulation in a polymeric matrix. In this work, we investigated the photosensitizing properties of the C60 molecule functionalized with organic units comprising thiophene or selenophene rings. The chemical structures of the synthesized dyads were characterized by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. The influence of the S/Se atoms and vinyl linkage between the organic unit and C60 on the absorptive and emissive properties of the dyads was investigated and correlated with their photosensitizing activity. For the latter, we used a standard chemical singlet oxygen trap. A selected dyad C60ThSe2 was also applied as a source of singlet oxygen in a model photocatalyzed synthesis of the fine chemical juglone from 1,5-dihydroxynapthalene. [ABSTRACT FROM AUTHOR]

Recent advances in machine-to-machine (M2M) communications, mini-hardware manufacturing, and micro computing have led to the development of the Internet of Things (IoT). The IoT is integrated with medical devices in order to enable better treatment, cost-effective medical solutions, improved patient monitoring, and enhanced personalized healthcare. This has led to the development of more complex and heterogeneous Internet of Medical Things (IoMT) systems that have their own operating systems and protocols. Even though such pervasive and low-cost sensing devices can bring about enormous changes in the healthcare sector, these are prone to numerous security and privacy issues. Security is thus a major challenge in these critical systems, one that inhibits their widespread adoption. However, significant inroads have been made by the on-going research, which powers the IoMT applications by incorporating prevalent security measures. In this regard, this paper highlights the significance of implementing key security measures, and essential aspects of the IoMT that make it useful for interconnecting various internal and external working domains of healthcare. This paper presents state-of-the-art techniques for securing IoMT systems, in terms of data transmission, collection, and storage. Furthermore, the paper also explores various security requirements, inherent design challenges, and various security techniques that could make the IoMT more secure and sustainable. Finally, the paper gives a panoramic view of the current status of research in the field and outlines some future research directions in this area. [ABSTRACT FROM AUTHOR]

We report the formation of an interconnected, three-dimensional, mesoporous polymeric fullerene oxide framework via thermal [3 + 2] cyclo-additions of monomeric C60 and fullerene oxides (C60On), formed upon thermal decomposition of C60Br24, causing the eliminations of bromine atoms in an oxygen atmosphere at an elevated temperature of 200 °C. The newly formed mesoporous fullerene oxide framework is found to be a low bandgap semiconductor capable of acting as a photocatalyst similar to graphitic C3N4. The sunlight-assisted photocatalytic degradation of the methylene blue dye is demonstrated. To have a better understanding of the mechanism of the [3 + 2] cyclo-additions of monomeric C60 and fullerene oxides, a theoretical investigation has been carried out and the energetics of the reaction C60O + C60 → C120O is calculated. [ABSTRACT FROM AUTHOR]

Digital healthcare services have seen significant growth in this decade and many new technologies have been thoroughly examined to provide efficient services through secure infrastructures. The Internet of Medical Things (IoMT) revitalizes a healthcare infrastructure by creating an interconnected, intelligent, accessible, and efficient network. While there have been many studies on possible device authentication techniques for the IoMT, there is still much work to be done in user authentication to provide sustainable IoT solutions. Graphical passwords, which use visual content such as images instead of traditional text-based passwords, can help users authenticate themselves. However, current schemes have limitations. Therefore, this paper proposes a novel graphical authentication scheme that uses multiple factors to register and authenticate users using simple arithmetic operations, machine learning for hand gesture recognition, and medical images for recall purposes. The proposed method is designed to keep the authentication process simple, memorable, and robust. To evaluate the proposed scheme, we use the Post-Study System Usability Questionnaire (PSSUQ) to compare it with PIN-based and pattern-based authentication techniques. While comparing treatment and comparison groups, system quality showed a 16.7% better score, information quality a 25% increase, interface quality a 40% increase, and overall quality showed a 25% increase. The proposed method successfully revitalizes the use of graphical passwords, specifically in the field of IoMT, by developing a user-friendly, satisfying, and robust authentication scheme. [ABSTRACT FROM AUTHOR]

A review of heteroditopic interlocked molecules and their application as receptors for simple inorganic ion pair species. The review details the design and ion recognition properties of the rotaxane and catenane receptors, as well as highlighting some of the experimental challenges; hence, it provides insight into possible future avenues of research in this youthful field. [ABSTRACT FROM AUTHOR]

This work focuses on exploring a new configuration for the reduction of water hardness based on the surface modification of polyurethane (PU) open cell foams by the deposition of thin graphene oxide (GO) washcoat layers. GO was deposited by the dip–squeeze coating procedure and consolidated by thermal treatment. The final washcoat load was controlled by performing consecutive depositions, after three of which, a GO inventory up to 27 wt% was obtained onto PU foams of 60 pores per inch (PPI). The GO-coated PU foams were assembled into a filter, and the performance of the system was tested by continuously feeding water with hardness in the 190–270 mgCa2+,eq·L−1 range. Remarkable results were demonstrated in terms of total adsorbing capacity, which was evaluated by measuring the outlet total hardness by titration and exhibited values up to 63 mgCa2+,eq·gGO−1 at a specific filtered water volume of 650 mLH2O·gGO−1, outperforming the actual state-of-the-art adsorbing capacity of similar GO-based materials. [ABSTRACT FROM AUTHOR]

The design, synthesis, and initial study of amino-functionalized porphyrins as a new class of bifunctional catalysts for asymmetric organophotocatalysis is described. Two new types of amine–porphyrin hybrids derived from 5,10,15,20-tetraphenylporphyrin (TPPH2), in which a cyclic secondary amine moiety is covalently linked either to a β-pyrrolic position (Type A) or to the p-position of one of the meso phenyl groups (Type B), were prepared by condensation, reductive amination, or amidation reactions from the suitable porphyrins (either formyl or methanamine derivatives) with readily available chiral amines. A preliminary study of the possible use of Type A amine–porphyrin hybrids as asymmetric, bifunctional organophotocatalysts was performed using the chiral, imidazolidinone-catalyzed Diels–Alder cycloaddition between cyclopentadiene 28 and trans-cinnamaldehyde 29 as a benchmark reaction. The yield and the stereochemical outcome of this process, obtained under purely organocatalytic conditions, under dual organophocatalysis, and under bifunctional organophotocatalysis, were compared. [ABSTRACT FROM AUTHOR]

Here, it is presented the fabrication of a low-cost and semitransparent three-layer graphene electrode (anode) based on an easily processable graphene derivative and the conductive polymer PH1000 (PEDOT:PSS). The graphene derivative was mechanically synthesized and suspended in water (SPGSW); its deposit was made directly by drop casting on a glass substrate. The multilayer nature of the SPGSW films was corroborated by Raman spectroscopy and a number of ∼ 7 graphene layers were estimated for the SPGSW film treated with hydroiodic acid (HI) and UV-ozone plasma, which was also corroborated theoretically (∼ 6 graphene layers). Furthermore, for the SPGSW film, a thickness of ∼ 5 nm was determined experimentally. The alternative three-layer graphene electrode showed a transmittance and an electrical resistance of ∼ 78% (at 550 nm) and ∼ 88 Ω/sq, respectively. These results are promising for this alternative electrode based on the graphene derivative and for potential application in photovoltaic devices beside other uses. [ABSTRACT FROM AUTHOR]

In this paper, the growth mechanism, structure, growth processes, growth kinetics, and optical, vibronic and electronic properties of metallocene-filled single-walled carbon nanotubes (SWCNTs) are considered. A description of the procedures used to fill the nanotubes is provided. An investigation of doping effects on metallicity-mixed SWCNTs filled with metallocenes by Raman spectroscopy, near edge X-ray absorption fine structure spectroscopy, photoemission spectroscopy, and optical absorption spectroscopy is described. The studies of doping effects on metallicity-sorted SWCNTs filled with metallocenes are discussed. Doping effects in metallicity-mixed and sorted SWCNTs upon the chemical transformation of encapsulated molecules are analyzed. A discussion of the modification of the electronic properties of filled SWCNTs is presented. Applications of metallocene-filled SWCNTs in electrochemistry, thermoelectric power generation, chemical sensors, and magnetic recording are discussed. [ABSTRACT FROM AUTHOR]

This paper is dedicated to the discussion of applications of carbon material in electrochemistry. The paper starts with a general discussion on electrochemical doping. Then, investigations by spectroelectrochemistry are discussed. The Raman spectroscopy experiments in different electrolyte solutions are considered. This includes aqueous solutions and acetonitrile and ionic fluids. The investigation of carbon nanotubes on different substrates is considered. The optical absorption experiments in different electrolyte solutions and substrate materials are discussed. The chemical functionalization of carbon nanotubes is considered. Finally, the application of carbon materials and chemically functionalized carbon nanotubes in batteries, supercapacitors, sensors, and nanoelectronic devices is presented. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) represent a promising emerging photovoltaic technology offering such benefits as light weight, mechanical flexibility, semitransparency, environmental friendliness and aesthetic design of solar panels. Furthermore, organic solar cells can be produced using scalable and high-throughput solution-based printing and coating technologies, which are expected to lead to very low product costs. Fullerene derivatives have been used as acceptor materials in virtually all efficient organic solar cells for more than two decades, following the demonstration of the first proof-of-concept devices in the middle of 1990s. Still, the power conversion efficiencies of fullerene-based organic solar cells became stuck at around 12% due to the suboptimal optoelectronic properties of conventional fullerene acceptors. Therefore, the latest efficiency records (>18%) for organic solar cells were set using different types of non-fullerene acceptor (NFA) materials with tailorable properties. However, NFA materials appeared to be very sensitive to light, thus impairing the operational stability of OSCs. On the contrary, there is growing evidence that rationally designed fullerene-based acceptors enhance the photostability of conjugated polymers and also NFAs, when used in ternary blends. Hence, a renaissance of fullerene-based materials is currently expected in the context of their use in multicomponent organic solar cells (e.g., as stabilizers) and also lead halide perovskite solar cells, where they play an important role of electron transport materials. The success in both of these applications requires the tunability of optoelectronic characteristics of fullerene derivatives. In particular, electron affinity of the fullerene cage has to be reduced in many cases to match the energy levels of other absorber material(s). Herein, we present a systematic review of different strategies implemented to reduce the acceptor strength of the fullerene derivatives and the results of their performance evaluation in OSCs with model conjugated polymers. Particular attention is paid to correlations between the chemical structure of organic addends and their influence on the electronic properties of the fullerene core. We believe this review would be valuable to researchers working on the rational design of new fullerene-based materials with tailored properties for photovoltaic and other electronic applications. [ABSTRACT FROM AUTHOR]

Electrical and optical properties of graphene/silver nanoparticles hybrid suspensions intended for use in inkjet printing technologies were studied. Few-layered graphene particles were manufactured via a direct ultrasonic-assisted liquid-phase exfoliation route in water/surfactant system, whereas silver nanoparticles were synthetized using a polyol process. Hybrid suspensions for graphene/silver nanoparticles mixtures showed significant reduction in mean particle size while electrical conductivity remained almost intact even after thorough centrifugation. Structuring effects in mixed colloids were very pronounced as both electrical conductivity and optical transmission showed maxima at 65 wt.% graphene. Suspensions with conductivities above 300 μSm/cm, much higher than previously reported, were obtained, and resulted in the manufacturing of films with less than 10% optical absorption throughout the visible region. These samples did not demonstrate absorption peaks attributed to silver nanoparticles' surface plasmon resonance, which is suitable for transparent electrode applications. Suspension properties at optimal composition (65 wt.% graphene) are very promising for printed electronics as well as transparent conductive coating applications. In the paper, we establish that the optimal suspension composition matches that of the film; therefore, more attention should be paid to carefully studying electrically conductive suspensions. [ABSTRACT FROM AUTHOR]

Large shaft usually achieves high surface quality through multi-pass grinding in practice. Common surface quality indexes include surface roughness and glossiness, which are not only required numerically, but also require high consistency of distribution along the whole shaft. In multi-pass grinding, these two indexes are affected by the process parameters and the surface quality of the previous grinding pass, which leads to the difficulty of modeling. In addition, due to the uneven distribution of actual grinding depth, the surface quality along the whole shaft is usually inconsistent, resulting in the need for multiple spark-out grinding passes to ensure consistency. In this study, the surface quality evolution models for surface roughness and glossiness based on Elman neural network are developed, which build regressions between process parameters, surface quality indexes of the previous grinding pass, and surface quality indexes of the current grinding pass. Moreover, a consistency control method of surface quality is proposed by adjusting the actual grinding depth within the dimensional accuracy tolerance range at the rough grinding stage. Experimental results show that the surface roughness and glossiness prediction errors of the surface quality evolution models are only 5.5% and 5.1%. The consistency control method guarantees the consistency of surface quality, reduces the grinding passes, and increases the grinding efficiency. [ABSTRACT FROM AUTHOR]

Binary and ternary complexes of europium fullerenes and diphthalocyanines with detonation nanodiamonds are obtained for the first time, which can serve as platforms for the delivery of these hydrophobic molecules into aqueous biological media for magnetic resonance imaging, photodynamic therapy, and diagnostics using luminescent labels. Detonation nanodiamonds (~4–5 nm in size) have a positive potential (30–70 mV) in an aqueous medium due to the groups (CH, COH) grafted to the surface by heat treatment in an atmosphere of hydrogen. When positively charged diamonds interact with electronegative hydrated fullerenes in an aqueous medium, the initial aggregates of each of the components are destroyed, and the electrostatic attraction between them leads to the formation of stable compact complexes ~20 nm in size, according to dynamic light scattering and neutron scattering in colloids (20°C). Binary complexes include, on average, two fullerene molecules per 30–40 diamond particles. Introducing diphthalocyanine molecules into a binary colloid yields stable ternary structures. The resulting complexes of diamonds, fullerenes, and diphthalocyanine molecules are promising for biomedical applications due to the luminescent and magnetic properties of the components. [ABSTRACT FROM AUTHOR]

This review discusses the phemenology of filling, the investigation of kinetics, and the electronic properties for applications of filled single-walled carbon nanotubes (SWCNTs), and summarizes five main achievements that were obtained in processing the spectroscopic data of SWCNTs filled with metal halogenide, metal chalcogenide, metal and metallocenes. First, the methods of processing kinetic data were developed to reveal precise trends in growth rates and activation energies of the growth of SWCNTs. Second, the metal-dependence of kinetics was revealed. Third, metallicity-sorted (metallic and semiconducting) SWCNTs were filled with a range of substances and the electronic properties were investigated. Fourth, new approaches to processing the data of spectroscopic investigations of filled SWCNTs were developed, which allowed more reliable and precise analysis of the experimental results. Fifth, the correlation between the physical and chemical properties of encapsulated substances and the electronic properties of SWCNTs were elucidated. These points are highlighted in the review. [ABSTRACT FROM AUTHOR]

Huntington's disease (HD) is one of the human neurodegenerative diseases for which there is no effective treatment. Therefore, there is a strong demand for a novel neuroprotective agent that can alleviate its course. Fullerene derivatives are considered to be such agents; however, they need to be comprehensively investigated in model organisms. In this work, neuroprotective activity of C60(OH)30 and C120O(OH)44 fullerenols was analyzed for the first time in a Drosophila transgenic model of HD. Lifespan, behavior, oxidative stress level and age-related neurodegeneration were assessed in flies with the pathogenic Huntingtin protein expression in nerve cells. Feed supplementation with hydroxylated C60 fullerene and C120O dimer oxide molecules was shown to diminish the oxidative stress level and neurodegenerative processes in the flies' brains. Thus, fullerenes displayed neuroprotective activity in this model. [ABSTRACT FROM AUTHOR]

The paper is dedicated to the discussion of kinetics of growth, and electronic properties of filled carbon nanotubes investigated by spectroscopy for applications. The paper starts with discussion of growth of carbon nanotubes inside metallocene-filled carbon nanotubes. Nickelocene, cobaltocene are considered for growth of carbon nanotubes. Then, the investigations of filled carbon nanotubes by four spectroscopic techniques are discussed. Among them are Raman spectroscopy, near edge X-ray absorption fine-structure spectroscopy, photoemission spectroscopy, optical absorption spectroscopy. It is discussed that metal halogenides, metal chalcogenides, metals lead to changes in electronic structure of nanotubes with n- or p-doping. The filling of carbon nanotubes with different organic and inorganic substances results in many promising applications. This review adds significant contribution to understanding of the kinetics and electronic properties of filled SWCNTs with considering new results of recent investigations. Challenges in various fields are analyzed and summarized, which shows the author's viewpoint of progress in the spectroscopy of filled SWCNTs. This is a valuable step toward applications of filled SWCNTs and transfer of existing ideas from lab to industrial scale. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of polishing protocols on the surface roughness of flowable and regular bulk fill composites. Five bulk fill composites were tested: SureFil SDR Flow (SDR), Tetric EvoFlow Bulk fill (TEF), Filtek Bulk Fill Flowable (FIF), Tetric EvoCeram Bulk Fill (TEC), and Filtek Bulk Fill Posterior (FIP). Two polishing protocols were tested: Sof-Lex and Astropol. Astropol created a smoother surface for FIP (P < .05); however, the polishing protocol did not influence surface roughness on TEC (P > .05). SDR, TEF, and FIF exhibited rougher surfaces when polished. Sof-Lex created rougher surfaces for bulk fill composites. It was concluded that surface roughness was related to material composition rather than the polishing system. [ABSTRACT FROM AUTHOR]

Compounds sensitive to reactive oxygen species are widely used in the study of processes in living cells and in the development of therapeutic agents for photodynamic therapy. In the present work, we have synthesized a dyad in which the BODIPY dye is chemically bound to 9,10-diphenylanthracene (DPA). Here, DPA acts as a specific sensor of singlet oxygen and BODIPY as a reference dye. We studied the photophysical properties of the BODIPY-DPA dyad and showed that energy transfer occurs between the chromophores. As a result, the compound has excitation maxima in the absorption region of both DPA and BODIPY, but the fluorescence emission occurs mainly from BODIPY. In the presence of singlet oxygen, the excitation maximum of DPA decreases, while the intensity of the excitation maximum of BODIPY remains almost unchanged. This allows the BODIPY-DPA dyad to be used as a ratiometric sensor of singlet oxygen. [ABSTRACT FROM AUTHOR]

Polarizability exaltation is typical for (C60)n nanostructures. It relates to the ratio between the mean polarizabilities of (C60)n and C60: the first one is higher than the n-fold mean polarizability of the original fullerene. This phenomenon is used in the design of novel fullerene compounds and the understanding of its properties but still has no chemical rationalization. In the present work, we studied the distributed polarizability of (C60)2 and isomeric (C60)3 nanoaggregates with the density functional theory method. We found that polarizability exaltation increases with the size of the nanostructure and originates from the response of the sp2-hybridized carbon atoms to the external electric field. The highest contributions to the dipole polarizability of (C60)2 and (C60)3 come from the most remote atoms of the marginal fullerene cores. The sp3-hybridized carbon atoms of cyclobutane bridges negligibly contribute to the molecular property. A similar major contribution to the molecular polarizability from the marginal atoms is observed for related carbon nanostructures isomeric to (C60)2 (tubular fullerene and nanopeanut). Additionally, we discuss the analogy between the polarizability exaltation of covalently bonded (C60)n and the increase in the polarizability found in experiments on fullerene nanoclusters/films as compared with the isolated molecules. [ABSTRACT FROM AUTHOR]

The mechanism of detonation synthesis of nanocarbons was successfully applied to obtaining 2D graphene structures. To this end, rejecting the composite explosive and switching to pure trinitrotoluene for optimizing the energy efficiency of the detonation synthesis was suggested. The validity of the proposed phenomenological model was confirmed by experimental data. Using a set of complementary research methods (electron microscopy, Raman spectroscopy, dynamic light scattering), a good agreement was demonstrated between the morphometric parameters of the synthesized powder particles and those characteristic of 2D graphene structures, graphene nanoplates (GNP). The obtained results allowed a conclusion that the proposed method offers a much more eco-friendly solution to the problem of disposal of expired ammunition compared to existing methods. [ABSTRACT FROM AUTHOR]

A semi-automated diffusion-dialysis purification procedure is proposed for the preparation of uncontaminated graphene oxide (GO) aqueous dispersions. The purification process is integrated with analytical-signal processing to control the purification degree online by several channels: oxidation-reduction potential, conductivity, and absorbance. This approach reduces the amounts of reagents for chemical treatment during dialysis. The total transition metal (Mn and Ti) content was reduced to a sub-ppb level (assessed by slurry nebulization in inductively coupled plasma optical atomic emission spectroscopy). Purified aqueous GO samples possess good stability for about a year with a zeta-potential of ca. −40 mV and a lateral size of ca. sub-µm. Purified GO samples showed increased antioxidant properties (up to five times compared to initial samples according to chemiluminometry by superoxide-radical (O2−) generated in situ from xanthine and xanthine oxidase with the lucigenin probe) and significantly decreased peroxidase-like activity (assessed by the H2O2–L-012 system). [ABSTRACT FROM AUTHOR]

The huge number of network traffic data, the abundance of available network features, and the diversity of cyber-attack patterns mean that intrusion detection remains difficult even though many earlier efforts have succeeded in building the Internet of Healthcare Things (IoHT). The implementation of an effective algorithm to filter out most of the probable outliers of Round Trip Time (RTT) of packets recorded in the Internet environment is urgently required. Congestion and interference in networks can arise when numerous biosensors in an IoHT system all attempt to communicate at once. Internet of Health Things networks are susceptible to both intra- and internetwork interference. In this research, the Server-Side Includes (SSI) attack is a key issue because it allows for network compromise as part of Internal Attacks. Despite recent advancements, SSI detection remains difficult due to the vast amounts of network traffic data, the abundance of network features, and the diversity of cyber-attack patterns (DDoS, DoS, Satan, spoofing, etc.). With the help of sensors, physiological data may be collected and sent to distant servers, where they can be analyzed in real time by doctors to help them catch diseases in their earliest stages. This is made possible by the Internet of medical things (IoMT). Wireless data transfer, however, leaves it vulnerable to hackers, especially if the data being transferred are particularly private or sensitive. Security measures designed for devices with more storage space and processing power will not work on those with less. However, machine learning for intrusion detection can give a tailored security response to the needs of IoMT systems. For SSI detection, current methods are either inefficient because of the large number of packets that need to be caught and analyzed or unsuccessful because of outlier values in the RTTs obtained from the captured TCP packets. To the same end, "downstream detection" refers to the process of calculating the total length of all connections made after a certain point. As a means of improving the SSI detection algorithm's throughput in a network environment, packet RTT outliers will be eliminated. Flow records are used as inputs by flow-based NIDS to determine whether or not a given flow is malicious. In order to detect middlebox-based attacks from two Medical Health IoT datasets, this paper proposes a unique architecture of explainable neural networks (XNN). The model's accuracy in classifying attacks in dataset 1 of the IoHT is 99.7%t, besides achieving 99.4% accuracy in categorising attacks on IoHT dataset 2. [ABSTRACT FROM AUTHOR]

We estimate theoretically the strong-field-modified vibrational parameters of three-atomic A B A molecules with D ∞ h symmetry in a laser-induced plasma. The linear CO 2 and CS 2 molecules in the X 1 Σ g state are considered as examples. We show that double degeneracy of the Π u mode is removed due to reduction of the A B A molecule symmetry by the laser field. The linear form of A B A molecule is preserved, the bond length being elongated. [ABSTRACT FROM AUTHOR]

Stretchable wireless power is in increasingly high demand in fields such as smart devices, flexible robots, and electronic skins. Thermoelectric devices are able to convert heat into electricity due to the Seebeck effect, making them promising candidates for wearable electronics. Therefore, high-performance conductive polymer-based composites are urgently required for flexible wearable thermoelectric devices for the utilization of low-grade thermal energy. In this review, mechanisms and optimization strategies for polymer-based thermoelectric composites containing fillers of different architectures will be introduced, and recent advances in the development of such thermoelectric composites containing 0- to 3-dimensional filler components will be presented and outlooked. [ABSTRACT FROM AUTHOR]

Encapsulation of atoms or small molecules inside fullerenes provides a unique opportunity for study of the confined species in the isolated cavity, and the synthesis of closed C60 or C70 fullerenes with enclosed atoms or molecules has recently developed using the method of 'molecular surgery'; in which an open-cage intermediate fullerene is the host for encapsulation of a guest species, before repair of the cage opening. In this work we review the main methods for cage-opening and closure, and the achievements of molecular surgery to date. 'Molecular surgery' is a useful method through which to create endohedral fullerenes that aren't accessible by conventional physical methods of trapping small atoms and molecules. Here, the authors review the organic chemistry behind molecular surgery, describing the methods to access open-cage intermediates alongside the cage-closing chemistry. [ABSTRACT FROM AUTHOR]

Fullerene derivatives offer great scope for modification of the basic molecule, often called a buckyball. In recent years, they have been the subject of numerous studies, in particular in terms of their applications, including in solar cells. Here, the properties of four recently synthesized fullerene C60 derivatives were examined regarding their optical properties and the efficiency of the charge transfer process, both in fullerene derivatives themselves and in their heterojunctions with poly (3-hexylthiophene). Optical absorption, electron spin resonance (ESR), and time-resolved photoluminescence (TRPL) techniques were applied to study the synthesized molecules. It was shown that the absorption processes in fullerene derivatives are dominated by absorption of the fullerene cage and do not significantly depend on the type of the derivative. It was also found by ESR and TRPL studies that asymmetrical, dipole-like derivatives exhibit stronger light-induced charge transfer properties than their symmetrical counterparts. The observed inhomogeneous broadening of the ESR lines indicated a large disorder of all polymer–fullerene derivative blends. The density functional theory was applied to explain the results of the optical absorption experiments. [ABSTRACT FROM AUTHOR]

The electropolymerization of metallo-octaethylporphyrins (OEP) containing copper, zinc or nickel metal were performed using cyclic voltammetry at three different potential ranges. The electropolymerized porphyrins were characterized by UV-Vis and Raman spectroscopies and the Soret band (393–445 nm) and Raman bands were used to assess the degree of electropolymerization obtained. The application for an analytical use of the modified electrodes to determine phenobarbital in aqueous solution was evaluated. The electropolymerized CuOEP produced at potentials ranging from 0.0 to 2.2 V was the best performer with a limit of detection (LoD) of 10 mg L−1 (43.07 µM), a linear range of 10–150 mg L−1 (43.07 to 646 µM), an average precision of 4.3% (%RSD) and an average % recovery of 101.34%. These results indicate that the CuOEP-modified electrode is suitable for the analysis of phenobarbital in human samples, as the concentration range varies from 10 to 40 mg L−1 (43.07 to 172.27 µM), typically found in antiepileptic treatments, to those at the toxic level (172–258 µM) or lethal levels (345–650 µM). [ABSTRACT FROM AUTHOR]

Overhauser dynamic nuclear polarization (ODNP) can be used as a tool for NMR signal enhancement and happens on very short time scales. Therefore, ODNP is well suited for the measurement of fast-flowing samples, even in compact magnets, which is beneficial for the real-time monitoring of chemical reactions or processes. ODNP requires the presence of unpaired electrons in the sample, which is usually accomplished by the addition of stable radicals. However, radicals affect the nuclear relaxation times and can hamper the NMR detection. This is circumvented by immobilizing radicals in a packed bed allowing for the measurement of radical-free samples when using ex situ DNP techniques (DNP build-up and NMR detection happen at different places) and flow-induced separation of the hyperpolarized liquid from the radicals. Therefore, the synthesis of robust and chemically inert immobilized radical matrices is mandatory. In the present work, this is accomplished by immobilizing the radical glycidyloxy-tetramethylpiperidinyloxyl with a polyethyleneimine (PEI) linker on the surface of controlled porous glasses (CPG). Both the porosity of the CPGs and also the size of the PEI-linker were varied, resulting in a set of distinct radical matrices for continuous-flow ODNP. The study shows that CPGs with PEI-linkers provide robust, inert and efficient ODNP matrices. [ABSTRACT FROM AUTHOR]

Integrating the internet of things (IoT) in medical applications has significantly improved healthcare operations and patient treatment activities. Real-time patient monitoring and remote diagnostics allow the physician to serve more patients and save human lives using internet of medical things (IoMT) technology. However, IoMT devices are prone to cyber attacks, and security and privacy have been a concern. The IoMT devices operate on low computing and low memory, and implementing security technology on IoMT devices is not feasible. In this article, we propose particle swarm optimization deep neural network (PSO-DNN) for implementing an effective and accurate intrusion detection system in IoMT. Our approach outperforms the state of the art with an accuracy of 96% to detect network intrusions using the combined network traffic and patient's sensing dataset. We also present an extensive analysis of using various Machine Learning(ML) and Deep Learning (DL) techniques for network intrusion detection in IoMT and confirm that DL models perform slightly better than ML models. [ABSTRACT FROM AUTHOR]