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Here, based on first-principles calculations and topological analysis, we show that the spin-polarized topological phase is present in a van der Waals (vdW) heterostructure WSe2/CrI3. We reveal that magnetism induced by proximity effects in the heterostructure breaks the time-reversal symmetry (TRS) and thus induces gapped topological edge states, exhibiting the TRS-breaking quantum spin Hall (QSH) effect. By applying a stress field, the WSe2/CrI3 heterostructure manifests enhanced spin polarization, Rashba splitting, and tunable bandgap. The TRS-breaking QSH effect observed in the WSe2/CrI3 heterostructure exhibits remarkable robustness against interlayer shearing. The distinct anisotropy associated with in-plane strain provides precise manipulation strategies for bandgap engineering. Notably, in-plane tensile strain can significantly increase the nontrivial bandgap by up to 98 meV, suggesting the magnetic WSe2/CrI3 heterostructure represents an outstanding platform for achieving the TRS-breaking QSH effect at room temperature. Our findings provide a theoretical foundation for the development of low-dissipation spintronic nanodevices. [ABSTRACT FROM AUTHOR]

In response to the pressing energy crisis, thermoelectric materials have emerged as promising solutions for converting waste heat into electrical energy. Meanwhile, low-dimensional thermoelectric materials with micro/nanoscale dimensions are playing an increasingly important role in chip thermal management and self-powered wearable electronic devices. This work investigates the thermoelectric properties of three SixGey monolayers, predicted through the approach that combines the advantages of silicene and germanene. Utilizing density functional theory and semiclassical Boltzmann transport theory, we systematically analyze crystal structures, stabilities, electrical and thermal transport, and thermoelectric properties of three stable SixGey monolayers. Compared to traditional two-dimensional materials such as silicene and germanene, the SixGey monolayers exhibit significantly enhanced Seebeck coefficients (∼100 μV/K) and reduced lattice thermal conductivity, ranging from 1.15 to 1.43 W m–1 K–1 at 300 K. These results demonstrate a significant improvement in the thermoelectric figure of merit (zT) compared to silicon (0.02) and germanium (0.05) monolayers, reaching values of 0.15 (GeSi), 0.13 (GeSi2), and 0.11 (Ge2Si) at 700 K, respectively. Our findings not only underscore the potential of SixGey monolayers as promising candidates for thermoelectric generators and thermoelectric coolers but also shed light on the utilization of silicon–germanium-based materials in thermoelectric generation and semiconductor cooling micro/nanoscale electronic devices. [ABSTRACT FROM AUTHOR]

Investigations into topological materials typically emphasize either electronic or phononic properties in isolation, often disregarding their coexistence, which could restrict the full realization of their practical applications. Here, we investigate HOD-graphene, an emergent macroporous carbon material featuring a unique configuration of hexagonal, octagonal, and dodecagonal carbon rings. This distinctive structure imparts exceptional mechanical properties to the material. Using a combination of first-principles calculations and symmetry analysis, we demonstrate that HOD-graphene hosts multiple nodal lines within both its electronic and phononic spectra. For the electronic bands, three nodal lines and several Dirac points manifest near the Fermi energy, generating unconventional electronic properties and distinct topological characteristics. Likewise, the phonon spectrum displays pronounced nodal lines, intricately associated with the material's vibrational modes. Our findings provide a promising platform for exploring the coexistence of electronic and phononic multiple nodal lines in two-dimensional materials, opening avenues for realizing exotic quantum phenomena. [ABSTRACT FROM AUTHOR]

Recently, two-dimensional (2D) ternary monolayer MSi2N4 (M = Mo, W) was synthesized by chemical vapor deposition. However, monolayer MSi2N4 (M = Mo, W) has an indirect bandgap, which seriously hinders its application in optoelectronic devices. Herein, we propose two MSi2N4/InS (M = Mo, W) van der Waals heterojunctions (vdWHs) possessing type-II band alignments by first-principles. Our results indicate that these vdWHs achieve an indirect-to-direct bandgap transition and exhibit fascinating optical absorption spectra in the range of visible light. Moreover, the light absorption efficiencies of both vdWHs are significantly strengthened, and the intrinsic electric field of vdWHs can effectively promote the separation of photogenerated electron–hole pairs. In particular, the most significant electron mobility of MSi2N4/InS (M = Mo, W) vdWHs is up to 6.6 × 103 cm2 V−1 s−1, demonstrating their considerable potential for optoelectronic device applications. Notably, MSi2N4/InS (M = Mo, W) vdWHs can facilitate water splitting due to their suitable band edges. Therefore, our findings demonstrate two 2D MSi2N4/InS (M = Mo, W) type-II vdWHs with fascinating potentials for photocatalysis. [ABSTRACT FROM AUTHOR]

Van der Waals heterostructures (vdWHs) are effective platforms for exploring various attractive topological phases. Here, based on the low-energy effective k · p model, we propose that the type-III vdWHs, which were previously considered as only belonging to trivial metallic phases, can realize the nontrivial quantum spin Hall (QSH) effect. We reveal that the band inversion of such a QSH phase is attributed to the band alignment of momentum space matching, i.e., the conduction band minimum and valence band maximum located at the same point in momentum space near the Fermi level. Moreover, using first-principles calculations, we show that the Mg(OH)2/Ga2O2 heterobilayer, a typical type-III vdWH with high thermodynamic stability, is an ideal candidate for achieving our strategy. We further calculate the helical gapless edge states and quantized spin Hall conductance, which are visible inside the global bandgap, thus facilitating the experimental observation. Our work offers a promising pathway for realizing the QSH phase in natural materials. [ABSTRACT FROM AUTHOR]

Background and Objectives: Fractures are common in pediatric trauma, and they are caused by a broad spectrum of factors. Only a few studies have discussed the mechanisms of injury and their relationships to different types of fractures. The most frequent type of fractures in different age groups remains unclear. Therefore, we aim to summarize the epidemiological characteristics of pediatric fractures in a medical center in Zhuhai, China from 2006 to 2021 and analyze the causes of fractures with the highest frequency in different age groups. Materials and Methods: We extracted the information from the Zhuhai Center for Maternal and Child Health Care of those under 14 years old who had fractures from 2006 to 2021. Results: We reviewed the information of 1145 children. The number of patients increased during the 15 years (p < 0.0001). The number of patients was significantly different between genders after Y2 (p = 0.014). In addition, more than two-thirds of patients (71.3%) had upper limb fractures, and all types of falls were the most common cause of fractures (83.6%). The incidence demonstrated an insignificant difference in age groups except for the fractures of humerus and radius. Moreover, we discovered that the prevalence of fall-related injuries decreased with age, while that of sports-related injuries increased with age. Conclusions: Our study demonstrates that the prevalence of fall-related injuries decreases with age, and that of sports-related injuries increases with age. Most patients have upper limb fractures, and all types of falls are the most common cause of fractures. Fracture types with the highest frequency differ in each age group. These findings might supplement current epidemiological knowledge of childhood fracture and provide references for decision-making in children's health policies. [ABSTRACT FROM AUTHOR]

The grain boundaries (GBs) composed of pentagons and octagons (558 GBs) have been demonstrated to induce attractive transport properties such as Van Hove singularity (VHS) and quasi-one-dimensional metallic wires. Here, we propose a monolayer carbon allotrope which is formed from the introduction of periodic 558 GBs to decorate intact graphene, termed as PHO-graphene. The calculated electronic properties indicate that PHO-graphene not only inherits the previously superior characteristics such as Van Hove singularity and quasi-one-dimensional metallic wires, but also possesses two twisted Dirac cones near the Fermi level. Further calculation finds that the Berry phase is quantized to ± π at the two Dirac points, which is consistent with the distribution of the corresponding Berry curvature. The parity argument uncovers that PHO-graphene hosts a nontrivial band topology and the edge states connecting the two Dirac points are clearly visible. Our findings not only provide a reliable avenue to realize the abundant and extraordinary properties of carbon allotropes, but also offer an attractive approach for designing all carbon-based devices. [ABSTRACT FROM AUTHOR]

Recently, centimeter-scale monolayer MoSi2N4 (α1-phase) was successfully synthesized in experiments with excellent ambient stability. However, it is an indirect band gap semiconductor, which hinders its wide application. Here, we systematically studied the stability of the structure and optoelectronic properties of two new α1-phase monolayers (MoSi2Sb4 and WSi2Sb4) and a new family of α2-phase monolayer MSi2Z4 (M = Mo, W; Z = P, As, Sb) using first-principles calculations. Our results indicated that all of these monolayer structures showed high structural stability, and the α2-phase structures are more stable than the α1-phase structures. Moreover, all of them have direct band gaps with fascinating optical absorption efficiencies ranging from infrared to visible light. Importantly, the high hole mobility (up to 105 cm2 V−1 s−1) reveals that these monolayer MSi2Z4 will have potential applications in photoelectric devices. In addition, α2-MoSi2P4 possesses a desirable power conversion efficiency of 20.3%. Interestingly, spin–orbit coupling plays a key role in exploring the optoelectronic properties of MSi2Z4 ternary compounds. These new ternary monolayer structures can effectively broaden the 2D materials family and provide promising potential candidates for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) harm human health and the ecological environment. This work demonstrated manganese oxide catalytic membrane coupled to biodegradation of toluene in a catalytic membrane biofilm rector (CMBfR). Toluene removal efficiency in CMBfR was up to 91% in a 200-day operation. Manganese oxide combined to membrane biofilm reactor could promote degradation of toluene. Manganese oxide catalysts were characterized by XRD, Raman, XPS, and FT-IR. Raman and XPS spectra verified the existence of Mn defects, adsorbed oxygen species, and the oxygen vacancy, which was catalytic of toluene on the Mn oxides coated membranes significantly. Pseudomonas, Hydrogenophaga, Flavobacterium, Bacillus, Clostridium and Prosthecobacter were the dominant bacteria of toluene degradation. Mn oxides catalysis could degrade toluene into intermediate products; these products were entered into the biological phase eventually metabolized to CO2 and H2O. These results show that the catalytic membrane biofilm reactor is achievable and opens new possibilities for applying the catalytic membrane biofilm reactor to VOCs treatment. [ABSTRACT FROM AUTHOR]

Objective: To review the treatment experience of neonatal humeral epiphyseal osteomyelitis retrospectively. Study design: Retrospective cohort study of infants with neonatal humeral epiphyseal osteomyelitis. Patients were divided into conservative group and surgical group, and the surgical group was subdivided into early and delayed surgical group. Results: In total, there were 7 patients in the conservative group and 24 in the surgical group. The length of hospital stay and intravenous course of antibiotic therapy were both significantly shorter in the surgical group (p < 0.001). The full recovery rate was also higher in the surgical group (83.3%) than the conservative group (14.3%) (p < 0.001). Early surgery group (n = 14) had an insignificantly higher positive rate of pus/aspirate culture and full recovery rate than delayed surgery group (n = 10). Conclusion: Surgical treatment for neonatal humeral epiphyseal osteomyelitis demonstrated significantly higher rates of positive culture for the pathogen, a shorter course of intravenous oral antibiotics, and lower incidence of growth abnormality than conservative treatment. In our institution, most of culture outcome Gram-positive bacteria, and early surgical treatment was recommended with better outcome than delayed surgical group. Empirical antibiotics should be tailored to the epidemiological characteristics of local virulent bacteria. [ABSTRACT FROM AUTHOR]

The synthesis of graphene-like structure [Fan et al., Science 372 (2021) 8527] with periodically embedded one-dimensional grain boundaries [Liu et al., Nat. Commun. 8 (2017)14924] is a strong incentive for exploration of carbon allotropes. In this work, a series of stable carbon allotropes with Dirac cones, (DSF)n-graphene, consisting of graphene nanoribbons and one-dimensional grain boundaries are proposed. The grain boundary composed of tetragonal and octagonal rings is constructed by a double stacking fault (DSF), where n refers to the width of the nanoribbon between the two grain boundaries. Interestingly, the Dirac cone of (DSF)n-graphene is mainly contributed by the atoms of grain boundaries, thus forming a one-dimensional conductive channel. Specifically, with the increase of n, the position of the Dirac points changes periodically on the two high symmetry lines, and the DSF ensures the robustness of the Dirac cones. Both (DSF)3-graphene and (DSF)4-graphene, as two prototypes, have Fermi velocities comparable to graphene, although the Dirac cones of the two are distributed on different high symmetry lines. Importantly, the calculation of surface states proves that (DSF)3-graphene and DSF4-graphene have nontrivial topological features. Furthermore, the massless Dirac fermions in the one-dimensional conductive channel bring many promising applications for future electronic devices. [ABSTRACT FROM AUTHOR]

Toluene biodegradation from synthetic waste gas by aerobic denitrification using nitrate as an electron acceptor in a biotrickling filter (BTF) was investigated. Toluene removal efficiency achieved 92.3% in 105 days of operation. Pseudomonas, Paracoccus, Flavobacterium, SM1A02, Acinetobacter, Blastocatella, Moheibacter, Chlamydiales, Rhodobacter, and Ottowia were dominant toluene-degrading genus. Bradyrhizobium, Comamonas, Cupriavidus, Pseudomonas, Pseuoxanthomonas, and Ralstonia simultaneously had the ability to participate the process of toluene biodegradation and denitrification. BTF used nitrate or oxygen as electron acceptor, toluene as electron donor, and thereby redox between toluene and nitrate was formed, to realize toluene oxidation. BTF was capable of toluene oxidation by denitrification. These results show that the aerobic denitrifying BTF is achievable and open new possibilities for applying the BTF to the removal of volatile organic compounds. [ABSTRACT FROM AUTHOR]

Soil pollution is an important problem. The organic components of soil pollution are complex, and pose a significant threat to human health. In this work, a low-temperature plasma vibrated bed is applied to remediation of soil polluted by organics, with attention focused on phenol as a model pollutant. In the experiment, many factors of phenol degradation are studied and determined, such as discharge voltage, carrier gas, and soil moisture content. Increasing vibration frequency, decreasing electrode spacing, increasing voltage and a weakly alkaline soil are conducive to the degradation of pollutants. Air and oxygen give better degradation than nitrogen. The active particles generated in the discharge, such as ·OH, HO and O, are shown to play an important role in degradation of phenol. In addition, maleic acid and oxalic acid are found as intermediate product during the process of phenol degradation. Furthermore, according to the qualitative and quantitative analysis of phenol degradation products, the degradation mechanism diagram of phenol in soil is drawn up, which is instructive to improve the performance of the plasma vibrated bed in the future research. [ABSTRACT FROM AUTHOR]