Interaction Distance Research Articles

Enhancing CH4 Capture from Coalbed Methane through Tuning van der Waals Affinity within Isoreticular Al-Based Metal-Organic Frameworks.

Efficient separation of the CH4/N2 mixture is of great significance for coalbed methane purification. It is an effective strategy to separate this mixture by tuning the van der Waals interaction due to the nonpolar properties of CH4 and N2 molecules. Herein, we prepared several isoreticular Al-based metal-organic frameworks (MOFs) with different ligand sizes and polarities because of their high structural stability and low cost/toxicity feature of Al metal. Adsorption experiments indicated that the CH4 uptake, Qst of CH4, and CH4/N2 selectivity are in the order of Al-FUM-Me (27.19 cm3(STP) g-1, 24.06 kJ mol-1 and 8.6) > Al-FUM (20.44 cm3(STP) g-1, 20.60 kJ mol-1 and 5.1) > Al-BDC (15.98 cm3(STP) g-1, 18.81 kJ mol-1 and 3.4) > Al-NDC (10.86 cm3(STP) g-1, 14.89 kJ mol-1 and 3.1) > Al-BPDC (5.90 cm3(STP) g-1, 11.75 kJ mol-1 and 2.2), confirming the synergetic effects of pore sizes and pore surface polarities. Exhilaratingly, the ideal adsorbed solution theory selectivity of Al-FUM-Me is higher than those of all zeolites, carbon materials, and most water-stable MOF materials (except Al-CDC and Co3(C4O4)2(OH)2), which is comparable to MIL-160. Breakthrough results demonstrate its excellent separation performance for the CH4/N2 mixture with good regenerability. The separation mechanism of Al-FUM-Me for the CH4/N2 mixture was elucidated by theoretical calculations, showing that the stronger affinity of CH4 can be attributed to its relatively shorter interaction distance with adsorption binding sites. Therefore, this work not only offers a promising candidate for CH4/N2 separation but also provides valuable guidance for the design of high-performance adsorbents.

The Pnictogen Bond: The Covalently Bound Arsenic Atom in Molecular Entities in Crystals as a Pnictogen Bond Donor.

In chemical systems, the arsenic-centered pnictogen bond, or simply the arsenic bond, occurs when there is evidence of a net attractive interaction between the electrophilic region associated with a covalently or coordinately bound arsenic atom in a molecular entity and a nucleophile in another or the same molecular entity. It is the third member of the family of pnictogen bonds formed by the third atom of the pnictogen family, Group 15 of the periodic table, and is an inter- or intramolecular noncovalent interaction. In this overview, we present several illustrative crystal structures deposited into the Cambridge Structure Database (CSD) and the Inorganic Chemistry Structural Database (ICSD) during the last and current centuries to demonstrate that the arsenic atom in molecular entities has a significant ability to act as an electrophilic agent to make an attractive engagement with nucleophiles when in close vicinity, thereby forming σ-hole or π-hole interactions, and hence driving (in part, at least) the overall stability of the system’s crystalline phase. This overview does not include results from theoretical simulations reported by others as none of them address the signatory details of As-centered pnictogen bonds. Rather, we aimed at highlighting the interaction modes of arsenic-centered σ- and π-holes in the rationale design of crystal lattices to demonstrate that such interactions are abundant in crystalline materials, but care has to be taken to identify them as is usually done with the much more widely known noncovalent interactions in chemical systems, halogen bonding and hydrogen bonding. We also demonstrate that As-centered pnictogen bonds are usually accompanied by other primary and secondary interactions, which reinforce their occurrence and strength in most of the crystal structures illustrated. A statistical analysis of structures deposited into the CSD was performed for each interaction type As···D (D = N, O, S, Se, Te, F, Cl, Br, I, arene’s π system), thus providing insight into the typical nature of As···D interaction distances and ∠R–As···D bond angles of these interactions in crystals, where R is the remainder of the molecular entity.

A nickel-based metal-organic framework for efficient SF6/N2 separation with record SF6 uptake and SF6/N2 selectivity

Seeking top-performing adsorbents with salient structural stability and renewability to realize efficient adsorption and enrichment of sulfur hexafluoride (SF6) from the gaseous blend is of great importance. Here, an ultramicroporous nickel-based metal-organic framework (MOF), termed Ni(NDC)(TED)0.5 with multiple naphthalene rings-functionalized pore environment, was synthesized to efficiently separate SF6/N2 mixture. Equilibrium adsorption results show that Ni(NDC)(TED)0.5 possesses a record IAST SF6/N2 selectivity (750) and SF6 uptake (61.86 cm3 cm−3), higher than all adsorbents reported so far, and resolves the trade-off phenomenon between SF6 adsorption capacity and SF6/N2 selectivity. In particular, the selectivity is 2.3 times that of the current highest material (SBMOF-1). Furthermore, theoretical calculations reveal that the pore centers of material are the most energetically-favorable preferential adsorption sites. Meanwhile, the stronger affinity between SF6 and framework is attributed to the shorter interaction distance between F atom on SF6 and pore wall. Breakthrough tests confirm this MOF can completely separate SF6/N2 mixture. The breakthrough uptake (56.60 cm3 cm−3) and dimensionless time (τ: 281.8) of this material for SF6 are separately 1.6 and 2.5 times that of the currently reported benchmark (Cu-MOF-NH2). In combination of excellent structural stability and recyclability, this material may be an ideal material for the recovery of SF6 from SF6/N2 mixture.

Comparison between Ab Initio Molecular Dynamics and OPLS-Based Force Fields for Ionic Liquid Solvent Organization.

OPLS-based force fields (FFs) have been shown to provide accurate bulk-phase properties for a wide variety of imidazolium-based ionic liquids (ILs). However, the ability of OPLS to reproduce an IL solvent structure is not as well-validated given the relative lack of high-level theoretical or experimental data available for comparison. In this study, ab initio molecular dynamics (AIMD) simulations were performed for three widely used ILs: the 1-butyl-3-methylimidazolium cation with chloride, tetrafluoroborate, or hexafluorophosphate anions, that is, [BMIM][Cl], [BMIM][BF4], and [BMIM][PF6], respectively, as a basis for further assessment of two unique IL FFs: the ±0.8 charge-scaled OPLS-2009IL FF and the OPLS-VSIL FF. The OPLS-2009IL FF employs a traditional all-atom functional form, whereas the OPLS-VSIL FF was developed using a virtual site that offloads negative charge to inside the plane of the ring with careful attention given to reproducing hydrogen bonding. Detailed comparisons between AIMD and the OPLS FFs were made based on radial distribution functions (RDFs), combined distribution functions (CDFs), and spatial distribution functions (SDFs) to examine cation-anion interactions and π+-π+ stacking between the imidazolium rings. While both FFs were able to correctly capture the general solvent structure of these popular ILs, the OPLS-VSIL FF quantitatively reproduced interaction distances more accurately. In addition, this work provides further insights into the different short- and long-range structure patterns of these popular ILs.

Effectiveness of Artificial Intelligence Multimedia Courseware in Classroom Teaching Application.

In the information age, traditional teaching methods can no longer meet the needs of modern students, and the emergence of multimedia courseware teaching mode just solves this problem. Under the trend of education integration, multimedia courseware is becoming more and more important in classroom teaching. Aiming at the characteristics of AI multimedia courseware classroom teaching mode, we discuss the practical application of AI multimedia courseware in classroom teaching and study the classroom teaching mode. Building a distance education platform through network technology can promote the education level. At the same time, the interactive distance education platform serves as a new network platform for system users in the website. In order to speed up the process of education informationization and improve the quality of education, this paper uses .NET technology and video transmission technology to design and implement a multiperson video conversation interactive distance education platform. Through the comparative experiment of two classes in Chengguan Middle School, using this platform for teaching, the average grade of students and the average grade of each course are better than the average grade of nonplatform classes, and the student's cognitive level has improved and is higher than the same level class. The results show that this platform can support a large number of online users and is very good for students of different majors. Through flexible and interactive course interaction, students are more convenient and more independent to learn but also reduce the teacher's time cost and greatly play the advantages of distance education, and the English teaching mode of artificial intelligence multimedia courseware is very popular with students. More than 60% of teachers are satisfied with the teaching mode and above.

Magnetic field interactions between current consumer electronics and cardiac implantable electronic devices.

Electronic products, including the iPhone 12, Apple Watch Series 6, and 2nd Generation AirPods, contain magnets to facilitate wireless charging. Permanent magnets may affect CIED magnet mode features by causing pacemakers to pace asynchronously and defibrillators to suspend arrhythmia detection. This study determined if CIEDs are affected by static magnetic fields from commonly used portable electronics (PE) at any distance and intends to reinforce FDA recommendations concerning consumer PE which contain permanent magnets. The maximum magnet field measurement was evaluated by a Gauss meter. The interaction between PE and CIEDs from Boston Scientific and Medtronic were tested ex vivo using a body torso model. The CIED was placed in physiologic saline, and the PE was placed at the surface and at increasing distances of 0.5, 1.0, and 1.5cm. Interactions were recorded by assessment of magnet mode status. The iPhone 12 had almost three times the static magnetic field measured at the surface as the iPhone XR, but magnetic field strength decreased dramatically with increasing distance. At the surface of the model, PE triggered magnet mode in all CIEDs. The maximum interaction distance for all combinations of CIEDs and Apple products was 1.5cm. The iPhone 12 produces a stronger static magnetic field than previous iPhone models. Magnets in PE tested will not interact with CIEDs when they are 15cm from the implanted device. Since no interaction was observed beyond 1.5cm, it is unlikely that magnet mode activation will occur during most daily activities.

Global structure identifiability and reconstructibility of an NDS with descriptor subsystems

This paper investigates requirements on a networked dynamic system (NDS) such that its subsystem interactions can be solely determined from experiment data or reconstructed from its overall model. The NDS is constituted from several subsystems whose dynamics are described through a descriptor form. Except regularity on each subsystem and the whole NDS, and the well-posedness of the whole NDS, no other restrictions are put on either subsystem dynamics or subsystem interactions. A matrix rank based necessary and sufficient condition is derived for the global identifiability of subsystem interactions, which leads to several conclusions about NDS structure identifiability when there is some a priori information. This matrix also gives an explicit description for the set of subsystem interactions that cannot be differentiated from experiment data only. In addition, a necessary and sufficient condition is obtained for the reconstructibility of subsystem interactions from an NDS descriptor form model. This condition can be verified with each subsystem separately and is therefore attractive in the analysis and synthesis of a large-scale NDS. Simulation results show that rather than increases monotonically with the distance of subsystem interactions to the undifferentiable set, the magnitude of the external output differences between two NDSs with distinct subsystem interactions increases much more rapidly when one of them is close to be unstable. In addition, directions of probing signals are also very important in differentiating external outputs of distinct NDSs. These findings are expected to be helpful in identification experiment designs, etc.

Cavitation characteristics analysis of a novel rotor-radial groove hydrodynamic cavitation reactor

Hydrodynamic cavitation was widely used in sterilization, emulsion preparation and other industrial fields. Cavitation intensity is the key performance index of hydrodynamic cavitation reactor. In this study, a novel rotor-radial groove (RRG) hydrodynamic cavitation reactor was proposed with good cavitation intensity and energy utilization. The cavitation performances of RRG hydrodynamic cavitation reactor was analyzed by utilizing computational fluid dynamics method. The cavitation intensity and the cavitation energy efficiency were used as evaluation indicators for RRG hydrodynamic cavitation reactor with different internal structures. The amount of generated cavitation for various shapes of the CGU, interaction distances and rotor speed were analyzed. The evolution cycle of cavitation morphology is periodicity (0.46 ms) in the CGU of RRG hydrodynamic cavitation reactor. The main cavitation regions of CGU were the outflow and inflow separation zones. The cavitation performance of rectangular-shaped CGU was better than the cylindrical-shaped CGU. In addition, the cavitation performance could be improved more effectively by increasing the rotor speed and decreasing the interaction distance. The research results could provide theoretical support for the research of cavitation mechanism of cavitation equipment.

A new concept for a gas proportional scintillation counter: the annular anode

A new design of a Gas Proportional Scintillation Counter (GPSC) for X-ray spectrometry is presented and a proof of concept is demonstrated. The proposed design is much simpler, having only one electrode, the anode. In addition, this electrode has an annular shape with its axis aligned with the photosensor axis. Since the scintillation region is limited to a small region near the anode, the solid angle subtended by the photocathode is similar relative to any position in the scintillation region and the amount of scintillation reaching the photosensor is independent from the position where the radiation interaction occurs. Standard GPSCs with uniform electric field design have the scintillation region parallel to the photosensor active area resulting in a dependence of the amount of light collected by the photosensor on the axial distance of the radiation interaction due to solid angle effects. These effects impose limitations on the size of the detector radiation window relative to the photosensor active area. Therefore, the annular anode allows to obtain a GPSC design with a larger radiation window relative to the photosensor area. A first GPSC prototype with a 10-cm diameter annular anode placed at a distance of 4.4 cm from the photosensor has an energy resolution of 14% for anode voltages of 8 kV and, according to simulations, it can reach 11% for anode voltages of 12 kV. This is worse than the values of 8–9% obtained with a standard GPSC which, on the other hand, have a window-to-photosensor diameter ratio lower than 0.8. Simulations have shown that the main factor degrading the energy resolution in this new design is the low number of photons impinging the photosensor due to the low solid angle subtended by the photosensor relative to the electroluminescence region of the detector. A compromise has to be made between the anode-to-photosensor diameter ratio as well as between the anode-to-photosensor distance and the energy resolution that can be achieved with the annular anode design.

CNT biodevices for early liver cancer diagnosis based on biomarkers detection- a promising platform

Regarding the serious threat of liver cancer owing to the concealment and hard detection of liver tumors at an early stage, primary diagnosis becomes quite crucial to guarantee human health. So, in this work platinum-decorated single-walled carbon nanotubes (SWCNTs) were proposed as superior nanodevice for the detection of 1-Octen-3-ol (octenol), decane, and hexanal as liver cancer biomarkers in the exhaled breath of the patients. Herein, density functional theory (DFT) calculations have been utilized to scrutinize the structural and electronic properties of pristine and Pt-decorated SWCNTs. Obtained results showed that the gas molecules were weakly physisorbed on the pristine SWCNT with negligible charge transfer and large interaction distances. Contrariwise, after the decoration of the SWCNT with Pt metal atom, significant charges are transferred, and energy adsorption increased. The results disclosed that the energy adsorption has been enhanced, for example, energy adsorption increased two times for decane and hexanal molecules (−1.06, and −1.07 eV) upon adsorption on Pt-decorated SWCNT. Moreover, substantial charges with amount of 0.238, 0.245, and 0.223 e were transferred from octenol, decane, and hexanal to the surface, respectively. So, investigations revealed that these compounds are strongly chemisorbed on Pt-SWCNT with small interaction distances and along with the short recovery time of 1.7, 83.4, and 123 s at room temperature toward octenol, decane, and hexanal, respectively which make it a compelling nanodevice. Considering the findings, Pt-SWCNT is an excellent substrate for the sense of liver cancer biomarkers with desired recovery time and the results demonstrate its feasibility for potential application in the near future in the field of liver cancer diagnosis.

Effect of the Cations (Na+, Ca2+, Fe2+, and Fe3+) on the Partially Hydrolyzed Polyacrylamide Shrinking by Molecular Dynamics Simulations

The presence of cations on injection fluids used during polymer flooding leads to viscosity losses of the polymeric solution and reduces its drag capacity. Thus, understanding the mechanisms of this chemical degradation is crucial to improving the efficiency of these treatments. This study focused on obtaining physical insights into the mechanisms involved in chemical degradation by molecular dynamics simulations. To do this, the interaction energies between a variety of cations present at polymer flooding (Na+, Ca2+, Fe2+, and Fe3+) and partially hydrolyzed polyacrylamide (HPAM) were calculated. First, several potentials for ion description were evaluated to guarantee a proper description of the ion hydration. Then, multiple simulations were carried out to understand the effect of each ion individually and the synergic effect of a mixture of ions (brine) on the HPAM chain shrinking. The radius of gyration of the HPAM chain was used as an evaluation parameter of the chain shrinking. The results indicate that multivalent cations have a stronger interaction with the polymer than the monovalent cations, exhibiting smaller interaction distances and higher interaction energies. These interaction energies are related to the ionic radius of the cations and their charge. Smaller cations get close enough to avoid the repulsion between charged monomers, being the Coulombic interactions the most important (two-third of the total interaction energy). Thus, the strongest interaction energies with the HPAM correspond to multivalent cations, which reduce the radius of gyration of the HPAM since they can interact with two carboxylate oxygen simultaneously. Interestingly was found a high dependence of the concentration of Fe3+ cations in the interaction with HPAM; at high concentrations, the cations cannot get close enough to interact with the polymer, but in low concentrations, the cations present the strongest interaction. These findings contribute to understanding the mechanisms that macroscopically are related to viscosity losses in the solution by the cation effect.

Nonlocal interactions between vegetation induce spatial patterning

Vegetation pattern provides useful signals for vegetation protection and can be identified as an early warning of desertification. In some arid or semi-arid regions, vegetation absorbs water through nonlocal interaction of roots. In this study, we present a vegetation model with nonlocal interaction which is characterized by an integral term with a kernel function. Mathematical analysis provides the conditions for the generation of stationary pattern. Numerical simulations exhibit different spatial distributions of vegetation. Densities of vegetation and water show an inverse relationship at same spatial locations due to water transport mechanism. The results reveal that the interaction intensity and the shape of the kernel function can cause the transition of vegetation pattern. Specifically, the vegetation biomass increases as the interaction intensity decreases or as the nonlocal interaction distance increases. We demonstrate that the nonlocal interactions between roots of vegetation is a key mechanism for the formation of vegetation pattern, which provides a theoretical basis for the preservation and restoration of vegetation.

Surface Interactions Studies of Novel Two-Dimensional Molybdenum Disulfide with Gram-Negative and Gram-Positive Bacteria

The interaction between two-dimensional nanoflakes and bacteria in water-based physiological liquids is a hot topic that unveils new types of phenomena and is fundamental to bioscience applications. In this work, we extend Derjaguin, Landau, Verwey, and Overbeek theory (DLVO theory) that describes the properties of nano-objects in solutions, to the case of two-dimensional nanoflakes interacting with bacteria cell membranes, both for Gram-positive and Gram-negative bacteria. We have studied the role of the bacterial shape, membrane potential, and two-dimensional nanomaterials nature showing the interplay of these parameters in determining whether the interactions are attractive or repulsive and whether electrostatic or van der Waals forces are dominant. We calculated the interaction distances at equilibrium for different bacterial species and hydrophobic nanomaterials such as in two environmentally friendly solvents, water and cyrene.

Exploration of phosphorene as doxorubicin nanocarrier: An atomistic view from DFT calculations and MD simulations

Potential capability of phosphorene nanosheet (PNS) as doxorubicin (DOX) nanocarrier was investigated using density functional theory (DFT) method and molecular dynamics (MD) simulations. Both DFT calculations and MD simulations revealed that the DOX molecule is adsorbed horizontally onto the PNS surface with the nearest interaction distance of 2.5 Å. The binding energy of DOX is predicted to be about − 49.5 kcal.mol−1, based on the DFT calculations. After DOX adsorption, the Eg value of PNS remains almost constant in both gas and solvent phases. The dynamical behavior of PNS-DOX was studied at T = 298, 310, and 326 K that reminiscent of room temperature, body temperature, and temperature of tumor after exposure to 808 nm laser radiation, respectively. The diffusion coefficient values of DOX molecule are proportional to temperature. We found that PNS can hold a high amount of DOX on both sides of its surface (66% in weight). MD simulations showed that the dynamical behavior of simulated systems are not affected by pH variances.

The Effect of a Sepsis Interprofessional Education Using Virtual Patient Telesimulation on Sepsis Team Care in Clinical Practice: Mixed Methods Study.

BackgroundImproving interprofessional communication and collaboration is necessary to facilitate the early identification and treatment of patients with sepsis. Preparing undergraduate medical and nursing students for the knowledge and skills required to assess, escalate, and manage patients with sepsis is crucial for their entry into clinical practice. However, the COVID-19 pandemic and social distancing measures have created the need for interactive distance learning to support collaborative learning.ObjectiveThis study aimed to evaluate the effect of sepsis interprofessional education on medical and nursing students’ sepsis knowledge, team communication skills, and skill use in clinical practice.MethodsA mixed methods design using a 1-group pretest-posttest design and focus group discussions was used. This study involved 415 undergraduate medical and nursing students from a university in Singapore. After a baseline evaluation of the participants’ sepsis knowledge and team communication skills, they underwent didactic e-learning followed by virtual telesimulation on early recognition and management of sepsis and team communication strategies. The participants’ sepsis knowledge and team communication skills were evaluated immediately and 2 months after the telesimulation. In total, 4 focus group discussions were conducted using a purposive sample of 18 medical and nursing students to explore their transfer of learning to clinical practice.ResultsCompared with the baseline scores, both the medical and nursing students demonstrated a significant improvement in sepsis knowledge (P<.001) and team communication skills (P<.001) in immediate posttest scores. At the 2-month follow-up, the nursing students continued to have statistically significantly higher sepsis knowledge (P<.001) and communication scores (P<.001) than the pretest scores, whereas the medical students had no significant changes in test scores between the 2-month follow-up and pretest time points (P=.99). A total of three themes emerged from the qualitative findings: greater understanding of each other’s roles, application of mental models in clinical practice, and theory-practice gaps. The sepsis interprofessional education—particularly the use of virtual telesimulation—fostered participants’ understanding and appreciation of each other’s interprofessional roles when caring for patients with sepsis. Despite noting some incongruities with the real-world clinical practice and not encountering many sepsis scenarios in clinical settings, participants shared the application of mental models using interprofessional communication strategies and the patient assessment framework in their daily clinical practice.ConclusionsAlthough the study did not show long-term knowledge retention, the use of virtual telesimulation played a critical role in facilitating the application of mental models for learning transfer and therefore could serve as a promising education modality for sepsis training. For a greater clinical effect, future studies could complement virtual telesimulation with a mannequin-based simulation and provide more evidence on the long-term retention of sepsis knowledge and clinical skills performance.

Effect of the Substrate on MoS2 Monolayer Morphology: An Integrated Computational and Experimental Study.

Synthesis of two-dimensional materials, specifically transition metal dichalcogenides (TMDs), with controlled lattice orientations is a major barrier to their industrial applications. Controlling the orientation of as-grown TMDs is critical for preventing the formation of grain boundaries, thus reaching their maximum mechanical and optoelectronic performance. Here, we investigated the role of the substrate's crystallinity in the growth orientation of 2D materials using reactive molecular dynamics (MD) simulations and verified with experimental growth using the chemical vapor deposition (CVD) technique. We considered MoS2 as our model material and investigated its growth on crystalline and amorphous silica and sapphire substrates. We revealed the role of the substrate's energy landscape on the orientation of as-grown TMDs, where the presence of monolayer-substrate energy barriers perpendicular to the streamlines hinder the detachment of precursor nuclei from the substrate. We show that MoS2 monolayers with controlled orientations could not be grown on the SiO2 substrate and revealed that amorphization of the substrate changes the intensity and equilibrium distance of monolayer-substrate interactions. Our simulations indicate that 0° rotated MoS2 is the most favorable configuration on a sapphire substrate, consistent with our experimental results. The experimentally validated computational results and insight presented in this study pave the way for the high-quality synthesis of TMDs for high-performance electronic and optoelectronic devices.

Chiral Bicyclic Imidazole-Catalyzed Direct Enantioselective C -Acetylation of Indolones

Chiral Bicyclic Imidazole-Catalyzed Direct Enantioselective <i>C</i> -Acetylation of Indolones

Self-assembly of Fe3O4 with natural tannin as composites for microalgal harvesting

Anisotropic structures and size control are attracting extensive attention owing to the effect on magnetic behavior and microalgal harvesting performance. Herein, a natural polymeric tannin was chosen as the shaping ligand to control the self-assembly of tannin-coated Fe3O4 (Fe3O4@tannin) for microalgal magnetic harvesting. Compared to naked Fe3O4, the Fe3O4@tannin presented a smaller hydrodynamic diameter of 287 nm, a larger magnetic saturation of 45.16 emu g−1, and a higher uptake capacity of 589.99 mg biomass per g of Fe3O4@tannin. Kinetic experimental data revealed that the magnetic harvesting followed a pseudo-second-order isotherm and the adsorption isotherm fitted the non-linear Freundlich model. The Fe3O4@tannin showed a good recycling potential with only a 7% decrease in harvesting efficiency after 5 cycles. The modified Deryaguin–Landau–Verwey–Overbeek (DLVO) interaction energies among the particles were used to evaluate the algal aggregation mechanism. Furthermore, the results indicated that the magnetic force contributed to the total interaction energies across a wide range of interaction distances. In situ microscopic observation also confirmed the formation of Fe3O4@tannin-to-algae aggregates, which further combined to form chain clusters and collided with free algal cells in the magnetophoretic process.

Child development and distance learning in the age of COVID-19

School closures, forcibly brought about by the COVID-19 crisis in many countries, have impacted children’s lives and their learning processes. The heterogeneous implementation of distance learning solutions is likely to bring a substantial increase in education inequality, with long term consequences. The present study uses data from a survey collected during Spring 2020 lockdown in France and Italy to analyze parents’ evaluations of their children’s home schooling process and emotional well-being at time of school closure, and the role played by different distance learning methods in shaping these perceptions. While Italian parents have a generally worse judgment of the effects of the lockdown on their children, the use of interactive distance learning methods appears to significantly attenuate their negative perception. This is particularly true for older pupils. French parents rather perceive that interactive methods are effective in mitigating learning losses and psychological distress only for their secondary school children. In both countries, further heterogeneity analysis reveal that parents perceive younger children and boys to suffer more during this period.

Spatial-Temporal Epidemiology of COVID-19 Using a Geographically and Temporally Weighted Regression Model

This article describes the application of spatial statistical epidemiological modeling and its inference and applies it to COVID-19 case data, looking at it from a spatial perspective, and considering time-series data. COVID-19 cases in Indonesia are increasing and spreading in all provinces, including Kalimantan. This study uses applied mathematics and spatiotemporal analysis to determine the factors affecting the constant rise of COVID-19 cases in Kalimantan. The spatiotemporal analysis uses the Geographically Temporally Weighted Regression (GTWR) model by developing a spatial and temporal interaction distance function. The GTWR model was applied to data on positive COVID-19 cases at a scale of 56 districts/cities in Kalimantan between the period of January 2020 and August 2021. The purpose of the study was to determine the factors affecting the cumulative increase in COVID-19 cases in Kalimantan and map the spatial distribution for 56 districts/cities based on the significant predictor variables. The results of the study show that the GTWR model with the development of a spatial and temporal interaction distance function using the kernel Gaussian fixed bandwidth function is a better model compared to the Ordinary Least Squares (OLS) model. According to the significant variables, there are various factors affecting the rise in cases of COVID-19 in the region of Kalimantan, including the number of doctors, the number of TB cases, the percentage of elderly population, GRDP, and the number of hospitals. The highest factors that affect COVID-19 cases are the high number of TB cases, population density, and the lack of health services. Furthermore, an area map was produced on the basis of the significant variables affected by the rise in COVID-19 cases. The results of the study provide local governments with decision-making recommendations to overcome COVID-19-related issues in their respective regions.