Exploration on Electronic Properties of Self-Assembled Indium Nitrogen Nanosheets and Nanowires by a Density Functional Method.

Equilibrium geometries and properties of self-assembled (InN)12n (n = 1-9) nanoclusters (nanowires and nanosheets) are studied using the GGA-PBE (general gradient approximation with Perdew-Burke-Ernzerh) method. The relative stabilities and growth patterns of semiconductor (InN)12n nanoclusters are investigated. The odd-numbered nano-size (InN)12n (n is odd) have weaker stabilities compared with the neighboring even-numbered (InN)12n (n is even) ones. The most stable (InN)48 nanosheet is selected as a building unit for self-assembled nano-size film materials. In particular, the energy gaps of InN nanoclusters show an even-odd oscillation and reflect that (InN)12n (n = 1-9) nanoclusters are good optoelectronic materials and nanodevices due to their energy gaps in the visible region. Interestingly, the calculated energy gaps for (InN)12n nanowires varies slightly compared with that of individual (InN)12 units. Additionally, the predicted natural atomic populations of In atoms in (InN)12n nanoclusters show that the stabilities of (InN)12n nanoclusters is enhanced through the ionic bonding and covalent bonding of (InN)12n (n = 1-9) nanoclusters.

HealthPrism: A Visual Analytics System for Exploring Children's Physical and Mental Health Profiles with Multimodal Data.

The correlation between children's personal and family characteristics (e.g., demographics and socioeconomic status) and their physical and mental health status has been extensively studied across various research domains, such as public health, medicine, and data science. Such studies can provide insights into the underlying factors affecting children's health and aid in the development of targeted interventions to improve their health outcomes. However, with the availability of multiple data sources, including context data (i.e., the background information of children) and motion data (i.e., sensor data measuring activities of children), new challenges have arisen due to the large-scale, heterogeneous, and multimodal nature of the data. Existing statistical hypothesis-based and learning model-based approaches have been inadequate for comprehensively analyzing the complex correlation between multimodal features and multi-dimensional health outcomes due to the limited information revealed. In this work, we first distill a set of design requirements from multiple levels through conducting a literature review and iteratively interviewing 11 experts from multiple domains (e.g., public health and medicine). Then, we propose HealthPrism, an interactive visual and analytics system for assisting researchers in exploring the importance and influence of various context and motion features on children's health status from multi-levelperspectives. Within HealthPrism, a multimodal learning model with a gate mechanism is proposed for health profiling and cross-modality feature importance comparison. A set of visualization components is designed for experts to explore and understand multimodal data freely. We demonstrate the effectiveness and usability of HealthPrism through quantitative evaluation of the model performance, case studies, and expert interviews in associated domains.

A theoretical study of the geometries, and electronic and surface properties of sphere-like (SiB)2n (n = 6-27, 30) functional nanomaterials.

The geometries and electronic properties of (SiB)2n (n = 6-27, 30) clusters are systematically investigated based on the gradient corrected Perdew-Burke-Ernzerhof exchange-correlation functional. In particular, the (SiB)36 cage is identified as the most stable nanocluster and (SiB)2n (n = 6-27, 30) nanocages prefer to have sphere-like geometries. By increasing the (SiB)2n (n = 6-27, 30) nanocage size, the calculated energy gaps of (SiB)2n (n = 6-27, 30) nanocages generally decrease and absorption wavelengths of the spectra of (SiB)2n (n = 6-27, 30) nanoclusters are elongated. The varied size of the nanoclusters leads to a quantum confinement effect indirectly. Interestingly, the nanosized (SiB)30-60 cages exhibit a stronger capacity for solar energy absorption or conversion due to both narrow HOMO-LUMO energy gaps and a large DOS near LUMO and HOMO levels. Finally, electronic charges transferred from silicon atoms to their surrounding boron atoms in (SiB)2n (n = 6-27, 30) contribute to the metallic characteristic and B-Si ionic bonds, and eventually enhance the stabilities of the nanocages.

Correction: A theoretical study of the geometries, and electronic and surface properties of sphere-like (SiB)2n (n = 6-27, 30) functional nanomaterials.

Correction for 'A theoretical study of the geometries, and electronic and surface properties of sphere-like (SiB)2n (n = 6-27, 30) functional nanomaterials' by Run-Ning Zhao et al., Phys. Chem. Chem. Phys., 2019, DOI: 10.1039/c9cp04900b.

Classification of Human Motions Using Micro-Doppler Radar in the Environments with Micro-Motion Interference.

Human motion classification based on micro-Doppler effect has been widely used in various fields. However, the motion classification performance would be greatly degraded if the wireless environment has non-target micro-motion interference. In this case, the interference signal aliases with the signal of target human motions and then generates cross-terms, making the signals hard to be used to identify target human motions. Existing methods do not consider this non-target micro-motion interference and have poor resistance to such interference. In this paper, we propose a target human motion classification system that can work in the scenarios with non-target micro-motion interference. Specifically, we build a continuous wave radar transceiver working in a low-frequency radar band using the software defined radio equipment Universal Software Radio Peripheral (USRP) N210 to collect signals. Moreover, we use Empirical Mode Decomposition and S-transform successively to remove non-target micro-motion interference and improve the time-frequency resolution of the raw signal. Then, an Energy Aggregation method based on S-method is proposed, which can suppress cross-terms and background noise. Furthermore, we extract a set of features and classify four human motions by adopting Bagged Trees. Extensive experiments using the test-bed show that under the scenarios with non-target micro-motion interference, 97.3% classification accuracy can be achieved.

Molecular dynamics study of segment peptides of Bax, Bim, and Mcl-1 BH3 domain of the apoptosis-regulating proteins bound to the anti-apoptotic Mcl-1 protein.

Mcl-1 has emerged as a potential therapeutic target in the treatment of several malignancies. Peptides representing BH3 region of pro-apoptotic proteins have been shown to bind the hydrophobic cleft of anti-apoptotic Mcl-1 and this segment is responsible for modulating the apoptotic pathways in living cells. Understanding the molecular basis of protein-peptide interaction is required to develop potent inhibitors specific for Mcl-1. Molecular dynamics simulations were performed for Mcl-1 in complex with three different BH3 peptides derived from Mcl-1, Bax, and Bim. Accordingly, the calculated binding free energies using MM-PBSA method are obtained and comparison with the experimentally determined binding free energies is made. The interactions involving two conserved charged residues (Aspi, and Arg/Lysi-4) and three upstream conserved hydrophobic residues (Leui-5, Ile/Vali-2, and Glyi-1, respectively) of BH3 peptides play the important roles in the structural stability of the complexes. The calculated results exhibit that the interactions of Bim BH3 peptides to Mcl-1 is stronger than the complex with Bax 19BH3 peptides. The hydrophobic residues (position i - 9, i - 8 and i + 2) of BH3 peptides can be involved in their inhibitory specificity. The calculated results can be used for designing more effective MCL-1 inhibitors.

Investigation on the mechanism for the binding and drug resistance of wild type and mutations of G86 residue in HIV-1 protease complexed with Darunavir by molecular dynamic simulation and free energy calculation.

Residue Gly86 is considered as the highly conversed residue in the HIV-1 protease. In our work, the detailed binding free energies for the wild-type (WT) and mutated proteases binding to the TMC-114 are estimated to investigate the protein-inhibitor binding and drug resistance mechanism by molecule dynamic simulations and molecular mechanics Poisson Boltzmann surface area (MM-PBSA) method. The binding affinities between the mutants and inhibitor are different than that in the wild-type complex and the major resistance to Darunavir (DRV) of G86A and G86S originate from the electrostatic energy and entropy, respectively. Furthermore, free energy decomposition analysis for the WT and mutated complexes on the basis of per-residue indicates that the mutagenesis influences the energy contribution of the residue located at three regions: active site region (residue 24-32), the flap region, and the region around the mutated residue G86 (residue 79-88), especially the flap region. Finally, further hydrogen bonds and structure analysis are carried out to detect the relationship between the energy and conformation. In all, the G86 mutations change the flap region's conformation. The experimental results are in good agreement with available results.

The investigations on HIV-1 gp120 bound with BMS-488043 by using docking and molecular dynamics simulations.

BMS-488043, like its predecessor BMS-378806, is a small molecule that can block the interactions between gp120 and CD4, and has shown good clinical efficacy. However, the crystal structure of drug-gp120 complexes or the full-length gp120 free of bound ligand is unpublished until now. Docking combined with molecular dynamics simulation is used to investigate the binding mode between BMS-488043 and gp120. On the basis of the analysis of the simulated results, the plausible binding mode is acquired, such as the changes of binding mode in the trajectory and the calculated binding free energy. Subsequently, a number of residues which make contacts with the small molecule are studied by binding free energy decomposition to understand the mutation experiments, such as Trp427, Ser375, and Thr257 residues with the help of the acquired binding mode above. Especially, the importance of the hydrophobic groove formed by residues Ile371 and Gly472 which bind BMS-488043 is elaborated, which has not been explored much. In addition, theoretical investigations on the dynamics behavior of the gp120 associated with BMS-488043 enhanced binding are performed; the results indicate that the BMS-488043 may be more deeply inserted into the Phe43 cavity compared with the previous binding mode acquired by docking.

Insights into the structural function of the complex of HIV-1 protease with TMC-126: molecular dynamics simulations and free-energy calculations.

The binding properties of the protein-inhibitor complex of human immunodeficiency virus type 1 (HIV-1) protease with the inhibitor TMC-126 are investigated by combining computational alanine scanning (CAS) mutagenesis with binding free-energy decomposition (BFED). The calculated results demonstrate that the flap region (residues 38-58) and the active site region (residues 23-32) in HIV-1 protease contribute 63.72% of the protease to the binding of the inhibitor. In particular, the mechanisms for the interactions of key residues of these species are fully explored and analyzed. Interestingly, the regression analyses show that both CAS and BFED based on the generalized Born model yield similar results, with a correlation coefficient of 0.94. However, compared to CAS, BFED is faster and can decompose the per-residue binding free-energy contributions into backbone and side-chain contributions. The results obtained in this study are useful for studying the binding mechanism between receptor and ligand and for designing potent inhibitors that can combat diseases.

Does the incoming oxygen atom influence the geometries and the electronic and magnetic structures of Co(n) clusters?

The small-sized Co(n)O (n = 1-5) clusters with different spin states have been systematically investigated by using the density-functional approach. The total energies, equilibrium geometries, and magnetic properties are discussed. Equilibrium geometries and the relative stabilities in terms of the calculated fragmentation energies are discussed, manifesting that the remarkable stable small-sized cluster corresponds to the Co(2)O isomer, and that the O atom prefers the surface-capped pattern on Co(n) (n > 2) clusters and bonds with three Co atoms simultaneously. Furthermore, the calculated averaged atomic magnetic moments of Co(n)O (n = 1-5) clusters exhibit that the septet Co(2)O structure has the biggest averaged atomic magnetic moment of 2.0 mu(B)/atom, it is interesting that the oxygen capped Co(n) (n = 1-5) clusters retain the magnetic properties of bare transition metal (TM) Co(n) clusters. In addition, the distribution of electron density of the HOMO states for the most stable Co(n)O clusters mainly localizes around Co(n) atoms while the distribution around O atom is very low, and their shapes of the HOMO and bonding properties between bare Co(n) clusters and Co(n)O clusters are obviously different. The calculated electron affinities and experimental results (J. Phys. Chem. A 2002, 106, 4891) show that the incoming oxygen atom causes a minor influence on the electronic properties of Co(n) clusters. Comparisons of the calculated ionization potentials (IPs) for CoO and Co(2)O clusters with available experimental measurements are made.

Geometries and stabilities of the carbon clusters with the rhodium impurity: a computational investigation.

A density functional study of the RhCn(n = 1-6) clusters with different spin states has been carried out systematically by using the B3LYP/Lan2DZ method. The equilibrium geometries associated with total energies and natural populations of RhCn (n = 1-6) clusters are calculated and presented. Stabilities and electronic properties are discussed in detail. The relative stabilities in term of the calculated fragmentation energies show that the lowest-energy RhCn clusters with rhodium atom being located at terminal of carbon chain are the linear geometries and the ground states of the RhCn clusters alternate between doublet (for n-odd members) and quartet (for n-even members) states. Furthermore, the calculated fragmentation energies of the RhCn show strong even-odd alternations: the RhCn clusters with an odd number of carbon atoms are more stable than those with an even number ones. In addition, we comment on the charge transfer and chemical bonding properties within the clusters.

Geometries, stabilities, and growth patterns of the bimetal Mo2-doped Sin (n=9-16) clusters: a density functional investigation.

The behaviors of the bimetal Mo-Mo doped cagelike silicon clusters Mo2Sin at the size of n=9-16 have been investigated systematically with the density functional approach. The growth-pattern behaviors, relative stabilities, and charge-transfer of these clusters are presented and discussed. The optimized geometries reveal that the dominant growth patterns of the bimetal Mo-Mo doped on opened cagelike silicon clusters (n=9-13) are based on pentagon prism MoSi10 and hexagonal prism MoSi12 clusters, while the Mo2 encapsulated Sin(n=14-16) frames are dominant growth behaviors for the large-sized clusters. The doped Mo2 dimer in the Sin frames is dissociated under the interactions of the Mo2 and Sin frames which are examined in term of the calculated Mo-Mo distance. The calculated fragmentation energies manifest that the remarkable local maximums of stable clusters are Mo2-doped Sin with n=10 and 12; the obtained relative stabilities exhibit that the Mo2-doped Si10 cluster is the most stable species in all different sized clusters. Natural population analysis shows that the charge-transfer phenomena appearing in the Mo2-doped Sin clusters are analogous to the single transition metal Re or W doped silicon clusters. In addition, the properties of frontier orbitals of Mo2-doped Sin (n=10 and 12) clusters show that the Mo2Si10 and Mo2Si12 isomers have enhanced chemical stabilities because of their larger HOMO-LUMO gaps. Interestingly, the geometry of the most stable Mo2Si9 cluster has the framework which is analogous to that of Ni2Ge9 cluster confirmed by recent experimental observation (Goicoechea, J. M.; Sevov, S. C. J. Am Chem. Soc. 2006, 128, 4155).

Geometries and magnetisms of the Zr(n) (n=2-8) clusters: the density functional investigations.

The geometries, stabilities, and electronic and magnetic properties of small-sized Zr(n) (n=2-8) clusters with different spin configurations were systematically investigated by using density functional approach. Emphasis is placed on studies that focus on the total energies, equilibrium geometries, growth-pattern behaviors, fragmentation energies, and magnetic characteristics of zirconium clusters. The optimized geometries show that the large-sized low-lying Zr(n) (n=5-8) clusters become three-dimensional structures. Particularly, the relative stabilities of Zr(n) clusters in terms of the calculated fragmentation energies and second-order difference of energies are discussed, exhibiting that the magic numbers of stabilities are n=2, 5, and 7 and that the pentagonal bipyramidal D(5h) Zr(7) geometry is the most stable isomer and a nonmagnetic ground state. Furthermore, the investigated magnetic moments confirm that the atomic averaged magnetic moments of the Zr(n) (n not equal to 2) display an odd-even oscillation features and the tetrahedron C(s) Zr(4) structure has the biggest atomic averaged magnetic moment of 1.5 mu(B)/at. In addition, the calculated highest occupied molecular orbital-lowest unoccupied molecular orbital gaps indicate that the Zr(n) (n=2 and 7) clusters have dramatically enhanced chemical stabilities.

Geometries and electronic properties of the neutral and charged rare earth Yb-doped Si(n) (n = 1-6) clusters: a relativistic density functional investigation.

The neutral and charged YbSi(n) (n = 1-6) clusters considering different spin configurations have been systematically investigated by using the relativistic density functional theory with generalized gradient approximation. The total bonding energies, equilibrium geometries, Mulliken populations (MP), Hirshfeld charges (HC), fragmentation energies, and highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps are calculated and discussed. The optimized geometries indicate that the most stable YbSi(n) (n = 1-6) clusters keep basically the analogous frameworks as the low-lying Si(n)(+1) clusters, while the charged species deviate from their neutral counterparts, and that the doped Yb tends to occupy the substitutional site of the neutral and charged YbSi(n) isomers. The relative stabilities are investigated in terms of the calculated fragmentation energies, exhibiting enhanced stabilities for the remarkably stable neutral and charged YbSi2 and YbSi5 clusters. Furthermore, the calculated MP and HC values show that the charges of the neutral and charged YbSi(n) clusters transfer from the Yb atom to Si(n) atoms and the Yb atom acts as an electron donor, and that the f orbitals of the Yb atom in the neutral and charged YbSi(n) clusters behave as core without involvement in chemical bonding. The calculated HOMO-LUMO gaps indicate that the YbSi2 and YbSi4+ clusters have stronger chemical stabilities. Comparisons of the Yb-doped Si(n) (n = 1-6) with available theoretical results of transition-metal-doped silicon clusters are made. The growth pattern is investigated also.