Attraction Energy Research Articles

Theoretical insights and implications of pH-dependent drug delivery systems using silica and carbon nanotube

In this paper we have studied the density functional theory of four drugs ibuprofen, alendronate, Sulfasalazine and paracetamol with quartz, propylamine, trimethylamine functionalized quartz and carboxyl modified carbon nanotube. The attractive and repulsive interaction energies between drugs and quartz is obtained at various pH values. The attractive and repulsive energies are well correlated with experimental drug loading and releasing behavior by mesoporous silica nanoparticles. Further, a theoretical model is developed that accounts the electrostatic interaction between silica and drug and the model can predict the drug loading and releasing behavior by silica nanoparticles at various pH values.Sulfasalazine can be taken orally and loaded with trimethyl ammonium functionalized mesoporous silica nanoparticles, which keeps the drug in tact with the carrier in the acidic environment of the stomach and releases it into the neutral or basic medium of the small intestine. Alendronate may be loaded and released from propylamine functionalized mesoporous silica nanoparticles in the ranges of 1–5 and > 8, respectively. Ibuprofen is absorbed in an acidic environment and released in basic conditions for carboxyl modified carbon nanotube. The loading and releasing pH ranges for paracetamol in trimethylammonium functionalized mesoporous silica nanoparticles are 4–8 and >8, respectively.We also convert the pH-dependent variant of the diffusion-controlled Higuchi equation. We have changed the original Higuchi equation to produce the pH-dependent variation by incorporating the Nernst-Planck equation into Flick's first law. The updated equation could be used to forecast when medication particles with varying release times will emerge from a nanoparticles matrix.

Electronic and Optical Properties of Finite Gallium Sulfide Nano Ribbons: A First-Principles Study

The electronic and optical properties of finite GaS nanoribbons are investigated using density functional theory calculations. The effect of size, edge termination, and chemical modification by doping and edge passivation are taken into account. The dynamical stability is confirmed by the positive vibration frequency from infrared spectra; further, the positive binding energies ensure the stable formation of the considered nanoribbons. Accurate control of the energy gap has been achieved. For instance, in armchair nanoribbons, energy gaps ranging from ~ 1 to 4 eV were obtained in varying sizes. Moreover, the energy gap can be increased by up to 5.98 eV through edge passivation with F-atoms or decreased to 0.98 eV through doping with Si-atoms. The density of states shows that the occupied molecular orbitals are dominated by S-atoms orbitals, while unoccupied ones are mostly contributed to by Ga orbitals. Thus, S-atoms will be the electron donor sites, and Ga-atoms will be the electron acceptors in the interactions that the nanoribbons might undergo. The nature of electron–hole interactions in the excited states was investigated using various indices, such as electron–hole overlapping, charge–transfer length, and hole–electron Coulomb attraction energy. The UV-Vis absorption spectra reveal a redshift by increasing the size in the armchair or the zigzag directions. Chemical functionalization shows a significant influence on the absorption spectra, where a redshift or blueshift can be achieved depending on the dopant or the attached element.

Morphological Transitions in Solutions of Macromolecules with Solvophilic Backbone and Orientationally Mobile Solvophobic Side Groups

A theoretical model describing the self-assembly in dilute solutions of amphiphilic macromolecules containing the backbone built of the solvophilic units (the P groups) and the solvophobic side chains (the H groups) possessing orientational mobility relative to the backbone units has been elaborated. In the framework of strong segregation limit (The size of the insoluble regions of the formed micelles is on the order of the hydrophobic side chains), state diagrams of the solution have been calculated with and without accounting for the orientational entropy contribution of the side groups to the total free energy of the solution at different thermodynamic qualities of solvent for the macromolecules and the grafting density of the H groups; the regions of stability of spherical and cylindrical micelles as well as planar bilayers (vesicles) have been revealed. It has been found that the contribution of the orientational entropy significantly affects the view of the state diagrams. In the case of considering the orientational mobility, the conditions of the cylindrical micelle stability are very sensitive to the change in the grafting density of the side groups. This sensitivity can be the reason why the formation of long cylindrical (wormlike) micelles is not observed in experiments and computer simulations. As earlier demonstrated at a qualitative level, the orientational mobility of the side groups can lead to the emergence of the orientation-induced attraction between the polymer micelles (A. I. Buglakov, D. E. Larin, and V. V. Vasilevskaya, Polymer 232, 124160 (2021)). In this study, exact analytical calculations of the energy of orientation-induced attraction for the case of the interaction between two planar bilayer micelles has been performed. At distances being of the order of the size of the side H group, the orientation-induced attraction forces are much stronger than the van der Waals forces and, hence, the orientation-induced attraction can be decisive in the formation of large aggregates observed in experiments.

Grain boundary segregation of nickel vacancies and space charge zone formation in NiO through interactions among Ni2+, O2−, and Ni3+

Defects like nickel vacancies (VNi″), holes (Ni3+) with different segregation tendencies to grain boundary (GB) can govern the properties of nickel oxide (NiO) – a promising material for energy applications. An atomistic model of non-stoichiometric NiO bicrystal with θ°001100 GB is developed to understand the segregation of VNi″, Ni3+ to GB from various ionic interactions. According to the model lattice positions available for VNi″ in GB possess lower attractive (from Ni2+-O2− interactions) and higher repulsive (from Ni2+-Ni2+ interactions) energies when compared with those in grain interior. This is due to the differences in these inter-ionic distances in GB and grain interior. Hence VNi″ segregate to GB. Contrarily, grain interior is more favorable for formation of Ni3+ in GB. These Ni3+ form a space charge zone adjacent to the GB. The model helps in understanding VNi″ segregation to GB and space charge zone formation.

Application of ultrasonic pre-treatment for flotation separation pyrrhotite from chlorite

The strengthen separation mechanism of pyrrhotite and chlorite by ultrasonic pre-treatment was revealed through ICP measurements, XPS measurements, SEM analyses, Zeta potential measurements, turbidity analyses, microscopic observation, adsorption capacity measurements, FTIR analyses and contact angle measurements. The results showed that ultrasonic pre-treatment can promote the dissolution of iron oxide particles on pyrrhotite surface and the desorption of iron ions adsorbed on chlorite surface in mixed minerals, which caused Zeta potential and point of zero charge(PZC) negatively shift on pyrrhotite/chlorite surface and convert mutual attraction energy to mutual repulsive energy, thus weaken the hetero-aggregation and enhance the separation between pyrrhotite and chlorite. Ultrasonic pre-treatment can optimize the adsorption capacity of butyl xanthate(BX) and the surface wettability on pyrrhotite surface, however, it has little effect on BX adsorption and wettability on chlorite surface, hence ultrasonic pre-treatment also can strengthen the separation of pyrrhotite from chlorite. Then the flotation experiment of artificial mixed pyrrhotite and chlorite was carried out, the results show that the recovery of pyrrhotite increases from 77.50 % to 81.72 % and the content of MgO decreases from 6.57 % to 5.74 % by the reaction of ultrasonic pre-treatment. Which further proof that ultrasonic pre-treatment can enhance the flotation separation of pyrrhotite from chlorite.

Analysis of Bonding by Quantum Chemistry─Resolving Delocalization Stabilization in a Mechanistic Basis and New Hückel Model

No general and unique understanding of the mechanism of covalent bonding in physical terms is provided by current computational methods or by a consensus among experts. Bonding is studied by energy decomposition analysis but may also be related to the interatomic motion of valence electrons within the molecule. This dynamical view of the mechanism of bonding is not widely appreciated. The aim here is to make it accessible by translation into a corresponding form of quantum chemical energy analysis. The interatomic electron motion is directly related to the delocalization taking place when atomic basis functions are combined into molecular orbitals. A "tribasis method" is introduced, allowing an atomic basis set to form subsets of (1) strictly localized atomic functions and (2) interatomic bridge functions which allow delocalization. Calculations can then identify ground states without (no bridge functions) and with delocalization. The scheme is based on exact quantum mechanics but demonstrated by a minimal basis treatment of H2+ and H2 in Hartree-Fock and valence bond approximations which show that the bond energy is a sum of repulsive localization and more strongly attractive delocalization energies. The tribasis method is used to reconstruct the Hückel theory of π-electron delocalization in planar hydrocarbon molecules to account for the "overlap problem". In its empirically fitted form, the new theory can accurately resolve both π → π* transition energy and aromatic stabilization energy. The picture of covalent bonding emerging from both hydrogenic and Hückel calculations is that there is a presence of a Pauli repulsion of localization which is overcome by a roughly twice as strong delocalization stabilization to form the bond.

Journal of Modern Thermodynamics in Mechanical System

Surface thermodynamics study is the application of colloidal science to an investigative search for the nature and rate of heat transfer on the surface of any particle-particle interaction. This paper presents the theory and a designed practical methodology for the demonstration of the Combined Hamaker Coefficient. The nature and effectiveness of any interaction between two or more particles can be determined using this thermodynamic approach. Samples of blood lymphocytes and HIV particles in a serum containing antiretroviral drug particles were used. The Hamaker concept based on Van der Waal’s theory for surface energy of attraction and repulsion can be demonstrated. The interfacial work done by particles can be investigated during their combined interaction in an in-vivo experiment. The data obtained can prove that the combined Hamaker coefficient when negative is responsible for particle-particle repulsion and positive for particle-particle attraction. This implies the repulsion of the viral particle in lymphocytes and drug particles in the intervening serum. The overall change in the energy potential of all particle matter is revealed to be a concurrent area of surface thermodynamics that employs mathematical concepts and software in the designing and formulation of drugs for the management of viral infections.

A novel reduced graphene oxide/polypyrrole conductive ceramic membrane enhanced electric field membrane bioreactor: Mariculture wastewater treatment performance and membrane fouling mitigation

A novel electric field membrane bioreactor (EMBR) for mariculture wastewater treatment utilizing reduced graphene oxide/polypyrrole ceramic membrane (rGO/PPy CM) was constructed and compared with MBRs using CM support and rGO/PPy CM. EMBR (rGO/PPy) obtained the highest pollutant removal rates (84.99% for TOC, 85.98% for NH4+-N), the lowest average membrane fouling rate (2.42 kPa/d) and pollutant adhesion performance by characterization. Meanwhile, the specific fluxes of characteristic foulants in EMBR were enhanced, and the total resistances were reduced by 8.12% to 62.46%. The underlying mechanisms included reduced attraction energy and improved electrostatic repulsion between contaminants in EMBR and membrane by the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory, DLVO model and force analysis. Therefore, this study complemented the understanding of antifouling effect and mechanism in EMBR by interaction energy and force analysis of characteristic pollutants. These findings also provided new insights into the application of EMBR for mariculture wastewater treatment.

Coulomb, exchange, kinetic, nuclear attraction and ionization energies of two-electron quantum dot with finite confinement potential

We have calculated Coulomb, exchange and configuration-average ionization energies for the ground and excited configurations in helium atom confined by a spherical cavity of finite barrier height. In addition, we have carried out kinetic energies, nuclear attraction energies, confining potential energies and probabilities of finding the electrons that occupy different subshells. In the strong and intermediate confinement regions, the results show that the barrier height of potential well and dot size have a strong influence on the energies and probabilities. The kinetic energies of electrons in 1s and nl orbitals increase as the height of the potential barrier increases, but in nuclear attraction energies the opposite behavior occurs. It is found that Coulomb and exchange energies rapidly decrease after the critical confinement radii, in which the electron in nl orbital escapes out of the well. The configuration-ionization confinement radius depends strongly on the potential barrier height.

Level Attraction due to Dissipative Phonon–Phonon Coupling in an Opto-Mechano-Fluidic Resonator

Dissipative couplings between solid-cavity optomechanical oscillators provide an underlying mechanism for many physical phenomena, such as level attraction, non-Hermitian parity-time-symmetric, and topological energy transfer with exceptional points (EPs). Until now, cavity optomechanical mode couplings on different phases of material have not been demonstrated. Here, we report the experimental demonstration of optomechanical mode dissipative coupling, mediated by high-quality-factor photon whispering-gallery modes, between a solid surface wave mode (SWM) and a liquid radial breathing mode (RBM), both of which coexist in an optofluidic microbubble resonator consisting of silica layer and liquid metal core. The resonant frequencies of solid-SWM and liquid-RBM depend mainly on the physical parameters of the silica and liquid metal, respectively. These physical parameters are all related to the microcavity temperature, which can be electrically controlled by wiring the liquid metal to a circuit. The dissipative level attraction between the solid-SWM and liquid-RBM is achieved by changing the current applied to the liquid metal. Our results open new avenues toward exploring topological energy transfer between solid and liquid materials or ultrasensitive biological sensing around EPs.

Pathogenicity Prediction of Single Amino Acid Variants With Machine Learning Model Based on Protein Structural Energies.

The most popular tools for predicting pathogenicity of single amino acid variants (SAVs) were developed based on sequence-based techniques. SAVs may change protein structure and function. In the context of van der Waals force and disulfide bridge calculations, no method directly predicts the impact of mutations on the energies of the protein structure. Here, we combined machine learning methods and energy scores of protein structures calculated by Rosetta Energy Function 2015 to predict SAV pathogenicity. The accuracy level of our model (0.76) is higher than that of six prediction tools. Further analyses revealed that the differential reference energies, attractive energies, and solvation of polar atoms between wildtype and mutant side-chains played essential roles in distinguishing benign from pathogenic variants. These features indicated the physicochemical properties of amino acids, which were observed in 3D structures instead of sequences. We added 16 features to Rhapsody (the prediction tool we used for our data set) and consequently improved its performance. The results indicated that these energy scores were more appropriate and more detailed representations of the pathogenicity of SAVs.

HYDRODYNAMIC-WAVE CALIBRATION OF POTENTIALS IN MAXWELL’S EQUATIONS: NON-LINEAR DYNAMICS AND COHERENCE, COLLAPSE, EXPANSION AND EXCHANGE INTERACTION OF INERTIAL DISSIPATIVE-COLLECTOR DISTURBANCES IN NON-EQUILIBRIUM MEDIA IN THE COMPLEX SPACE. SPIRAL TURBULENCE AND COHERENT STRUCTURES OF THREE-DIMENSIONAL TIME

The results of the hydrodynamic-wave calibration of the potentials in Maxwell’s equations and their analogs for the gravitational field, which combine Euler’s hydrodynamics, Maxwell’s electrodynamics, and d’Alembert’s wave apparatus with quantum principles, are given. The nonlinearity of the equations for the vector-potential with the velocity dimension ensures the interrelationship of different field forms and the cascade transport of energy by the disturbance spectrum. The obtained solutions of these equations for inertial dissipative-collector disturbances, which are characterized by a balance of local and convective acceleration, and also balance local dissipation (accumulation) with local metainertia. The vector-potential (wave function) of such forms includes a complex Euler exponent, the phase of which depends on the coordinates of the disturbances paired in the complex space – without distinguishing its real or imaginary half. Reasoned constancy of the phase, which ensures the coherent nature of the propagation of running field forms in complex space, as well as in topologically adequate three-dimensional time. The latter is considered in a cylindrical coordinate system that combines spiral and jet time forms. The correspondence of the components to the Laplace operator (in the spherical spatial coordinate system associated with the pair of disturbances) with respect to the near-acting centrifugal energy of repulsion and the long-range exchange energy of attraction, which collectively provide the mechanisms of collapse, expansion, and dynamic balance of the pair, has been revealed. Coherent resonant forms of motion with a three-dimensional topology of time are highlighted, which are widely represented, in particular, on the spectra of collider resonances, as well as on the spectra of technical, hydrodynamic, geophysical, and space turbulence. It is noted that such turbulence is described precisely by Maxwell’s equations in the hydrodynamic-wave calibration of potentials, and not by the Navier-Stokes equations, or by the truncated equations of magnetohydrodynamics, which completely ignore the displacement current in Maxwell’s equations. The obtained calculation results are confirmed by actual data in the systems of different levels of the organization. The main role of inertial dissipative-collector disturbances in the processes of dynamic thermoregulation of the Earth’s climate during the cyclical change of climatic optimums during ice ages has been established. In this context, criticism of the current noisy concepts of global warming, which exaggerate anthropogenic factors without taking into account the dominant natural factors, is presented. It is indicated that these factors should be considered in an expanded format of complex space and three-dimensional time without artificial constructions and self-limitations inherent, in particular, in modern standard physical models Lambda-CDM and SM.

Defects and frustration in the packing of soft balls

This work introduces the Hookean-Voronoi energy, a minimal model for the packing of soft, deformable balls. This is motivated by recent studies of quasi-periodic equilibria arising from dense packings of diblock and star polymers. Restricting to the planar case, we investigate the equilibrium packings of identical, deformable objects whose shapes are determined by an N-site Voronoi tessellation of a periodic rectangle. We derive a reduced formulation of the system showing at equilibria each site must reside at the “max-center” of its associated Voronoi region and construct a family of ordered “single-string” minimizers whose cardinality is O(N2). We identify sharp conditions under which the system admits a regular hexagonal tessellation and establish that in all cases the average energy per site is bounded below by that of a regular hexagon of unit size. However, numerical investigation of gradient flow of random initial data, reveals that for modest values of N the system preponderantly equilibrates to quasi-ordered states with low energy and large basins of attraction. For larger N the distribution of equilibria energies appears to approach a δ-function limit, whose energy is significantly higher than the ground state hexagon. This limit is possibly shaped by two mechanisms: a proliferation of moderate-energy disordered equilibria that block access of the gradient flow to lower energy quasi-ordered states and a rigid threshold on the maximum energy of stable states.

A poroelasticity theory for soil incorporating adsorption and capillarity

Adsorption and capillarity, in the order of high free energy to low, are the two soil–water interaction mechanisms controlling the hydro-mechanical behaviour of soils. Yet most of the poroelasticity theories of soil are based on capillarity only, leading to misrepresentations of hydro-mechanical behaviour in the low free energy regime beyond vaporisation. This inability is reasoned to be caused by two major limitations in the existing theories: missing interparticle attraction energy and incomplete definition of adsorption-induced pore-water pressure. A poroelasticity theory is formulated to incorporate the two soil–water interaction mechanisms, and the transition between them – that is, condensation/vaporisation, by expanding the classical three-phase mixture system to a four-phase mixture system with adsorptive water as an additional phase. An interparticle attractive stress is identified as one of the key sources for deformation and strength of soils induced by adsorption and is implemented in the poroelasticity theory. A recent breakthrough concept of soil sorptive potential is utilised to establish the physical link between adsorption-induced pore-water pressure and matric suction. The proposed poroelasticity theory can be reduced to several previous theories when interparticle attractive stress is ignored. The new theory is used to derive the effective stress equation for variably saturated soil by identifying energy-conjugated pairs. The derived effective stress equation leads to Zhang and Lu's unified effective stress equation, and can be reduced to Bishop's effective stress equation when only the capillary mechanism is considered and to Terzaghi's effective stress equation when a saturated condition is imposed. The derived effective stress equation is experimentally validated for a variety of soil in the full matric suction range, substantiating the validity and accuracy of the poroelasticity theory for soil under variably saturated conditions.

Superstrong Chemical Bonding of Noble Gases with Oxidoboron (BO+) and Sulfidoboron (BS+).

Inspired by the overwhelming exploration of noble gas-boron (Ng-B) bond containing chemical compounds, the stability of the Ng bound BY+ and AlY+ (Y = O and S) has been investigated by using various ab initio based quantum chemical methods. Ng atoms are found to form exceptionally strong bonds with BO+ species in the predicted NgBO+ (Ng = He-Rn) complexes with remarkably high Ng-B dissociation energies ranging from 138.0 to 462.2 kJ mol-1 for the He-Rn series. It is the highest ever Ng-B binding energy in conjunction with the smallest Ng-B bond length for any of the cationic species involving a Ng-B bond as reported until today. More importantly, the calculated Ng-B bond lengths have been found to be much lower than the respective covalent limits in both NgBO+ and NgBS+ ions. The electronegativity difference between O and S atoms has been reflected nicely in the Ng-B and Ng-Al binding energies, which are found to be 91.9-346.5, 9.6-169.2, and 6.8-142.1 kJ mol-1 in NgBS+, NgAlO+, and NgAlS+, respectively. The strong covalent bonding between Ng and B/Al atoms in the predicted chemical systems has also been supported by the natural bonding orbital (NBO) and electron density based atoms-in-molecule (AIM) analysis. In addition, the energy decomposition analysis (EDA) in combination with the natural bond orbital for chemical valence (NOCV) indicates that the orbital interaction term is the prime contributor to the total attraction energy in the Ng-B and Ng-Al bonds. Furthermore, Ng-B and Ng-Al bonding can be assessed using the donor-acceptor model where the σ-electron donation that takes place from Ng (HOMO) → XY+ (LUMO) (X = B and Al; Y = O and S) is the major contributor to the orbital interaction energy. All the computational results along with the very recent experimental observation of ArOH+ and NgMX (Ng = Ar-Xe; M = Cu, Ag, Au; X = F, Cl) clearly indicate that it might be possible to synthesize and characterize these superstrong complexes, NgXY+ (Ng = He-Rn; X = B and Al; Y = O and S), under suitable experimental technique(s).

Slope–temperature faceting diagram for macrosteps at equilibrium

Faceting diagrams between surface slope and temperature are calculated numerically based on statistical mechanics for inclined surfaces between (001) and (111) surfaces at equilibrium. A lattice model is employed that includes point-contact-type step–step attractions from the quantum mechanical couplings between neighbouring steps. Comparing the obtained faceting diagrams with the phase diagram for step bunching proposed by Song and Mochrie for Si(113), the effective step–step attraction energy for Si(113) is approximately estimated to be 123 meV. The slope dependences of the mean height of the faceted macrosteps with a (111) side surface and that with a (001) side surface are calculated using the Monte Carlo method. The faceting diagrams can be used as a guide for controlling the assembling/disassembling of faceted macrosteps for designing new surface arrangements.

Perfluoroalkylated Catholyte Harnessing Multiple Fluoride Bond Breaking for Lithium Primary Batteries

Lithium primary batteries, with theoretical energy densities 3x higher than the rechargeable systems, are critical for applications where recharging is impossible or impractical, such as medical implants, unmanned vehicles, and remote monitoring. The current energy leader among commercial primaries is the Li−carbon monofluoride (CFx) battery, which has the highest theoretical energy density (2180 Wh/kgCFx) and up to 800 Wh/kg achieved in packaged cells. The solid CFx (0 < x ≤ 1.3) particles enable excellent safety and shelf stability, but also result in limited rate capability due to low electronic conductivity. Unfortunately, despite the increasing demand for high-energy Li primaries, the field is maturing with few fundamental innovations in cell chemistries in the past 40 years. To design battery chemistries that can surpass the energy of Li−CFx cell, herein, we examined the possibility to conduct multi-electron carbon reduction in high F content perfluoroalkyl groups (RF = −CnF2n+1, with F/C ratios of x>2) using liquid phase reactants. First, using liquid perfluoroalkyl iodides (CFI) as a model system, we investigated the governing factors for C−F bond redox, including supporting solvent viscosity, CFI chain length and concentration, discharge rate, and temperature. Up to 8 e− transfer per CFI (>1.3 e− per C, or 8/13 available F) is achievable with low reactant concentrations (0.1 M) and rates (20 μA/cm2). CFI catholyte sees challenges at high reactant concentrations and/or rates, as premature cell termination caused by deactivation of intermediates was observed. Therefore, to address this issue, we examined multiple handles in molecular structure to further tune the C−F bond activity. By replacing the I-ligand in CFI with an aromatic structure, the obtained fluoro-aromatics demonstrate close-to-full defluorination of RF group, yielding up to 15 e− (out of 17 available F) transfer per molecule, and attractive gravimetric energies of up to 1785 Wh/kgfluoro-aromatic, at high potentials (up to 2.6 V vs. Li/Li+) and concentrations (up to 1 M). Additionally, the voltage compatibility of the fluoro-aromatics with CFx enabled the hybridization of the catholyte and solid cathode in one cell. The hybrid cells provide opportunity to maximize the active material loading at cell-level, showing strong potential to further improve the energy densities over existing battery systems.

Quantum chemical simulation of hydrogen adsorption in pores: A study by DFT, SAPT0 and IGM methods

Hydrogen as a versatile energy carrier continues to attract research attention in the field of applied chemistry. One of the fundamental issues on the way to hydrogen economy is the difficulty of hydrogen storage. Physical adsorption of hydrogen in pores is a feasible and effective method of hydrogen storage. Among existing hydrogen-adsorbing materials, carbon nanostructures possess a number of advantages due to their high adsorption capacity, significant strength and low weight. In this work, we use the modern methods of quantum chemistry (DFT, SAPT0 and IGM) to study the adsorption of molecular hydrogen in a series of simulated slit-like carbon micropores with a distance between the walls of d = 4–10 Å, including the introduction of an H2 molecule into a pore, filling pores with these molecules and investigating the interactions between H2 molecules inside the pores. It was found that, depending on the value of parameter d, adsorbed hydrogen molecules form one (d = 6, 7 Å) or two layers (d = 8, 9, 10 Å) inside the pore. At the same time, for pores with small d values, high potential barriers to the introduction of H2 into a pore were observed. The decomposition of the interaction energy into components showed dispersion interactions to make a major contribution to the energy of attraction (72–82%). Moreover, an increase in the number of H2 molecules adsorbed in the pore decreases the significance of dispersion interactions (up to 61%) and increases the contribution of electrostatic and induction interactions to intermolecular attraction. Gravimetric density (GD) values were determined for pores with d = 6, 7, 8, 9, 10 Å, comprising 1.98, 2.30, 2.93, 3.25 and 4.49 wt%, respectively. It is assumed that the revealed peculiarities of hydrogen adsorption in pores will contribute to the use of carbon porous structures as a medium for hydrogen storage.

Tuning the surface chemistry of 2D MXenes for optimizing the micellization of bio-targeted carriers

Using nanocarriers to deliver drugs to cancer cells is an effective way to treat cancer. However, this method faces several challenges, including the instability of nanocarriers, and the appropriate method for the synthesis of nanocarriers. In this regard, in this work, the effect of the two-dimensional MXene in increasing the stability of riboflavin-targeted PLGA-PEG nanocarriers for delivering doxorubicin (Dox) has been investigated using molecular dynamics simulation. In this study, the role of surface chemistry engineering of MXene in optimizing Dox-loaded micelles has been studied. On the other hand, the effect of the microfluidic method on the synthesis of nanocarriers has been investigated. According to the obtained results, the use of MXene has outstandingly increased the stability of Dox-loaded nanocarriers. MXene increases the attraction energy between micelles from −600 Kj/mol to −1700 Kj/mol. But the use of hydrophilic functional groups in the MXene has reduced the stability of nanocarriers. The molecular analysis approves the greater stability of nanocarriers synthesized by the microfluidic method in comparison to non-microfluidic method. Finally, this could lead to the widespread use of microfluidic synthesis as well as MXene in the synthesis of nanocarriers.

Comprehensively understanding fouling properties of cake and bulk sludge in an anammox membrane bioreactor: Focusing on the composition, interfacial thermodynamics and microbial community

A more comprehensive investigation into fouling properties of cake and bulk sludge played an essential role in better understanding membrane fouling caused by the bio-cake formation in an anammox membrane bioreactor (MBR). In this work, the cake and bulk sludge from a stable anammox MBR were analyzed with the composition, interfacial thermodynamics and microbial community. Physicochemical analysis indicated that cake sludge agglomerated into larger flocs with a denser structure and a higher protein/polysaccharide (PN/PS) ratio as compared with bulk sludge. It also revealed that cake sludge was found to have looser protein secondary structures and more hydrophobic components than those of bulk sludge, which means the differences in surface hydrophobicity between two sludges might play a key role in revealing anammox sludge aggregation and further cake layer formation process. The dominant role of hydrophobic attraction energies between cake sludge and membrane surface at a shorter separation distance (< 2 nm), after the analysis of the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) method, confirmed cake layer formation process related with surface hydrophobicity. Furthermore, biological analysis demonstrated that the relative microbial abundances of Candidatus_Brocadia and Candidatus_Kuenenia in cake sludge were much greater than those of bulk sludge, implying a higher biofouling potential for them. Overall, this study fills the gap in understanding the mechanism between anammox sludge properties and cake formation, which provides basic knowledge for membrane fouling control in anammox MBR.