Nurses' knowledge and confidence in recognizing and managing patients with sepsis: A multi-site cross-sectional study.

AIMS: (1) To examine registered nurses' knowledge and confidence in recognizing and managing to patients with sepsis and (2) identify nurse and workplace factors that influence their knowledge on sepsis. DESIGN: A multi-site, cross-sectional survey. METHODS: An online survey was developed and content validated. Data was collected from registered nurses working in the inpatient wards and emergency departments of three hospitals of a single healthcare cluster in Singapore during August 2021. Statistical analyses of closed-ended responses and content analysis of open-ended responses were undertaken. RESULTS: A total of 709 nurses completed the survey. Nurses possessed moderate levels of knowledge about sepsis (mean score = 10.56/15; SD = 2.01) and confidence in recognizing and responding to patients with sepsis (mean score = 18.46/25; SD = 2.79). However, only 369 (52.0%) could correctly define sepsis. Nurses' job grade, nursing education level and clinical work area were significant predictors of nurses' sepsis knowledge. Specifically, nurses with higher job grade, higher nursing education level or those working in acute care areas (i.e. emergency department, high dependency units or intensive care units) were more likely to obtain higher total sepsis knowledge scores. A weak positive correlation was observed between sepsis knowledge test scores and self-confidence (r = .184). Open comments revealed that participants desired for more sepsis education and training opportunities and the implementation of sepsis screening tool and sepsis care protocol. CONCLUSION: A stronger foundation in sepsis education and training programs and the implementation of sepsis screening tools and care bundles are needed to enhance nurses' knowledge and confidence in recognizing and managing patients with sepsis. IMPACT: The findings of this study are beneficial to administrators, educators and researchers in designing interventions to support nurses in their role in recognizing and responding to sepsis.

van der Waals heterostructures based on MSSe (M = Mo, W) and graphene-like GaN: enhanced optoelectronic and photocatalytic properties for water splitting.

The geometric structure, electronic, optical and photocatalytic properties of MSSe-g-GaN (M = Mo, W) van der Waals (vdW) heterostructures are investigated by performing first-principles calculations. We find that the MoSSe-g-GaN heterostructure exhibits type-II band alignment for all stacking patterns. While the WSSe-g-GaN heterostructure forms the type-II or type-I band alignment for the stacking model-I or model II, respectively. The average electrostatic potential shows that the potential of g-GaN is deeper than the MSSe monolayer, leading to the formation of an electrostatic field across the interface, causing the transfer of photogenerated electrons and holes. Efficient interfacial formation of interface and charge transfer reduce the work function of MSSe-g-GaN vdW heterostructures as compared to the constituent monolayer. The difference in the carrier mobility for electrons and holes suggests that these heterostructures could be utilized for hole/electron separation. Absorption spectra demonstrate that strong absorption from infrared to visible light in these vdW heterostructures can be achieved. Appropriate valence and conduction band edge positions with standard redox potentials provide enough force to drive the photogenerated electrons and holes to dissociate water into H+/H2 and O2/H2O at pH = 0.

Electronic properties and enhanced photocatalytic performance of van der Waals heterostructures of ZnO and Janus transition metal dichalcogenides.

Vertical stacking of two-dimensional materials into layered van der Waals heterostructures has recently been considered as a promising candidate for photocatalytic and optoelectronic devices because it can combine the advantages of the individual 2D materials. Janus transition metal dichalcogenides (JTMDCs) have emerged as an appealing photocatalytic material due to the desirable electronic properties. Hence, in this work, we systematically investigate the geometric features, electronic properties, charge density difference, work function, band alignment and photocatalytic properties of ZnO-JTMDC heterostructures using first-principles calculations. Due to the different kinds of chalcogen atoms on both sides of JTMDC monolayers, two different possible stacking patterns of ZnO-JTMDC heterostructures have been constructed and considered. We find that all these stacking patterns of ZnO-JTMDC heterostructures are dynamically and energetically feasible. Moreover, both ZnO-MoSSe and ZnO-WSSe heterostructures are indirect band gap semiconductors and present type-I and type-II band alignments for model-I and model-II, respectively. The Rashba spin polarization of the ZnO-WSSe heterostructure for model-I is greater than that in the others. Furthermore, valence (conduction) band edge potentials are calculated to understand the photocatalytic behavior of these systems. Energetically favorable band edge positions in ZnO-Janus heterostructures make them suitable for water splitting at zero pH. We found that the ZnO-Janus heterostructures are promising candidates for water splitting with conduction and valence band edges positioned just outside of the redox interval.

Theoretical exploration of the potential applications of Sc-based MXenes.

Herein, we systematically explored the electronic properties of Sc-based MXenes via first-principles calculations, with the aim to extend their applicability. OH-Functionalized carbides and OH/SH-terminated nitrides manifest ultralow work functions, potential in field-effect transistors. Furthermore, we identified three novel semiconductors (Sc2CCl2, Sc2C(SH)2, and Sc2NO2). Specifically, Sc2NO2 is a spin gapless semiconductor, promising for spintronics. Type-II heterojunctions are readily available between Sc-based semiconducting MXenes, facilitating charge separation for optoelectronics and solar energy conversion. Further photocatalytic analysis indicates that Sc2CCl2 is capable of oxidizing H2O into O2.

Optical and thermoelectric properties of new Janus ZnMN2 (M = Ge, Sn, Si and N = S, Se, Te) monolayers: a first-principles study.

Thermoelectric materials have received great interest because they directly tap into the vast reserves of currently underused thermal energy, in an environmentally friendly manner. In this work, we investigated the electronic, optical and thermoelectric properties of novel ZnMN2 (M = Ge, Sn, Si and N = S, Se, Te) monolayers by performing density functional theory calculations. The dynamic and thermal stabilities of ZnMN2 (M = Ge, Sn, Si and N = S, Se, Te) monolayers were confirmed by their phonon band structures and ab initio molecular dynamics (AIMD) simulations, which showed that all the studied monolayers are stable. Calculated electronic band structures showed that ZnSiTe2, ZnGeSe2, and ZnSnTe2 have a direct band gap, while the remaining monolayers have an indirect band gap. Optical properties in terms of the imaginary part of the dielectric function have also been investigated, which showed that all the first excitonic peaks lie in the visible region. Transport coefficients, such as the Seebeck coefficient (S), electrical conductivity (σ) and power factor (PF) were calculated using the Boltzmann theory and plotted against chemical potential. The results demonstrated that the peak values of the p-type region for the PF are greater than those of the n-type region. Notably, ZnSiTe2 exhibits a large PF due to its smaller Seebeck coefficient and higher electrical conductivity compared to ZnSnS2, indicating that it is a promising candidate for thermoelectric applications. Our findings reveal that ZnMN2 (M = Ge, Sn, Si and N = S, Se, Te) monolayers open up new possibilities for optoelectronics and thermoelectric device applications.

Efficient Detection of Nerve Agents through Carbon Nitride Quantum Dots: A DFT Approach.

V-series nerve agents are very lethal to health and cause the inactivation of acetylcholinesterase which leads to neuromuscular paralysis and, finally, death. Therefore, rapid detection and elimination of V-series nerve agents are very important. Herein, we have carried out a theoretical investigation of carbon nitride quantum dots (C2N) as an electrochemical sensor for the detection of V-series nerve agents, including VX, VS, VE, VG, and VM. Adsorption of V-series nerve agents on C2N quantum dots is explored at M05-2X/6-31++G(d,p) level of theory. The level of theory chosen is quite adequate in systems describing non-bonding interactions. The adsorption behavior of nerve agents is characterized by interaction energy, non-covalent interaction (NCI), Bader's quantum theory of atoms in molecules (QTAIM), frontier molecular orbital (FMO), electron density difference (EDD), and charge transfer analysis. The computed adsorption energies of the studied complexes are in the range of -12.93 to -17.81 kcal/mol, which indicates the nerve agents are physiosorbed onto C2N surface through non-covalent interactions. The non-covalent interactions between V-series and C2N are confirmed through NCI and QTAIM analysis. EDD analysis is carried out to understand electron density shifting, which is further validated by natural bond orbital (NBO) analysis. FMO analysis is used to estimate the changes in energy gap of C2N on complexation through HOMO-LUMO energies. These findings suggest that C2N surface is highly selective toward VX, and it might be a promising candidate for the detection of V-series nerve agents.

Enhanced magneto-optical rotation of probe field in thermal medium via spontaneous generated coherence.

A four-level double lambda closed atomic configuration is considered to study the polarization plane rotation of the probe beam through cold as well as thermal Rb[Formula: see text] atomic medium by varying the spontaneously generated coherence (SGC). Magnetic field and strong coupling field are applied to the atomic configuration. The light-matter interaction leads to enhanced the magneto-optical rotation. The intensity of the applied fields plays promising role in the generation and enhancement of birefringence. It ultimately enhances the polarization plane rotation of the probe beam in the Doppler medium. In the presence of both SGC and Doppler broadening effects, the optical rotation and transmission of the weak light beam are modified and controlled as well, which have potential applications in magnetometery and laser frequency stabilization.

Generation of cross section for neutron induced nuclear reaction on iridium and tantalum isotope using machine learning technique.

In this work, we proposed a new approach in generating nuclear data using machine learning techniques. This paper focused on generation of nuclear cross section for neutron induced-nuclear reaction on iridium isotopes (Ir-191) and tantalum isotopes (Ta-181) target, specifically 191Ir (n,p)191Os and 181Ta (n, 2n)180Ta using random forest algorithms. The input consists of experimental datasets obtained from EXOR and simulated datasets from TALYS 1.9. We found that the regression curve generated by our model is in good agreement with the evaluated nuclear data library ENDF/B-VII.0, which is set as the benchmark. This shows a potential in building a machine learning model for generating nuclear cross section data for both well studied and understudied nuclear reaction.

First-principles study of the electronic structures and optical and photocatalytic performances of van der Waals heterostructures of SiS, P and SiC monolayers.

Designing van der Waals (vdW) heterostructures of two-dimensional materials is an efficient way to realize amazing properties as well as open up opportunities for applications in solar energy conversion, nanoelectronic and optoelectronic devices. The electronic structures and optical and photocatalytic properties of SiS, P and SiC van der Waals (vdW) heterostructures are investigated by (hybrid) first-principles calculations. Both binding energy and thermal stability spectra calculations confirm the stability of these heterostructures. Similar to the corresponding parent monolayers, SiS-P (SiS-SiC) vdW heterostructures are found to be indirect type-II bandgap semiconductors. Furthermore, absorption spectra are calculated to understand the optical behavior of these systems, where the lowest energy transitions lie in the visible region. The valence and conduction band edges straddle the standard redox potentials of SiS, P and SiC vdW heterostructures, making them promising candidates for water splitting in acidic solution.

A first-principles study of electronic structure and photocatalytic performance of GaN-MX2 (M = Mo, W; X= S, Se) van der Waals heterostructures.

Modeling novel van der Waals (vdW) heterostructures is an emerging field to achieve materials with exciting properties for various devices. In this paper, we report a theoretical investigation of GaN-MX2 (M = Mo, W; X= S, Se) van der Waals heterostructures by hybrid density functional theory calculations. Our results predicted that GaN-MoS2, GaN-MoSe2, GaN-WS2 and GaN-WSe2 van der Waals heterostructures are energetically stable. Furthermore, we find that GaN-MoS2, GaN-MoSe2 and GaN-WSe2 are direct semiconductors, whereas GaN-WS2 is an indirect band gap semiconductor. Type-II band alignment is observed through PBE, PBE + SOC and HSE calculations in all heterostructures, except GaN-WSe2 having type-I. The photocatalytic behavior of these systems, based on Bader charge analysis, work function and valence and conduction band edge potentials, shows that these heterostructures are energetically favorable for water splitting.

Van der Waals heterostructures of SiC and Janus MSSe (M = Mo, W) monolayers: a first principles study.

Favorable stacking patterns of two models with alternative orders of chalcogen atoms in SiC-MSSe (M = Mo, W) vdW heterostructures are investigated using density functional theory calculations. Both model-I and model-II of the SiC-MSSe (M = Mo, W) vdW heterostructures show type-II band alignment, while the spin orbit coupling effect causes considerable Rashba spin splitting. Furthermore, the plane-average electrostatic potential is also calculated to investigate the potential drops across the heterostructure and work function. The imaginary part of the dielectric function reveals that the first optical transition is dominated by excitons with high absorption in the visible region for both heterostructures. Appropriate band alignments with standard water redox potentials enable the capability of these heterostructures to dissociate water into H+/H2 and O2/H2O.

Cs2NaGaBr6: a new lead-free and direct band gap halide double perovskite.

In this work, we have studied new double perovskite materials, A2 1+B2+B3+X6 1-, where A2 1+ = Cs, B2+ = Li, Na, B3+ = Al, Ga, In, and X6 1-. We used the all electron full-potential linearized augmented plane wave (FP-LAPW+lo) method within the framework of density functional theory. We used the mBJ approximation and WC-GGA as exchange-correlation functionals. We optimized the lattice constants with WC-GGA. Band structures were calculated with and without spin-orbit coupling (SOC). Further, band structures for Cs2LiGaBr6 and Cs2NaGaBr6 were calculated with SOC + mBJ to correct the band gap values with respect to experimental value. We obtained direct bandgaps at Γ-point of 1.966 eV for Cs2LiGaBr6 and 1.762 eV for Cs2NaGaBr6, which are similar to the parent organic-inorganic perovskite (MAPI) CH3NH3PbI3 (E g = 1.6 eV). Total and partial density of states were analyzed to understand the orbital contribution of Cs, Na, Li, Ga and Br near the Fermi level. The optical properties in terms of real and imaginary ε, refractive index n, extinction coefficient k, optical conduction σ, absorption I, and reflectivity R were calculated. A study of the elastic and mechanical properties shows that both materials are thermodynamically stable. A stable, direct bandgap and a gap value close to those of MAPI make Cs2NaGaBr6 a great competitor in the Pb-free hybrid perovskite solar cells world.

Correction: Cs2NaGaBr6: a new lead-free and direct band gap halide double perovskite.

[This corrects the article DOI: 10.1039/D0RA01764G.].

Type-I band alignment of BX-ZnO (X = As, P) van der Waals heterostructures as high-efficiency water splitting photocatalysts: a first-principles study.

In this work, we perform first-principles calculations to examine the electronic, optical and photocatalytic properties of the BX-ZnO (X = As, P) heterostructures. The interlayer distance and binding energy of the most energetically favorable stacking configuration are 3.31 Å and -0.30 eV for the BAs-ZnO heterostructure and 3.30 Å and -0.25 eV for the BP-ZnO heterostructure. All the stacking patterns of the BX-ZnO heterostructures are proved to have thermal stability by performing AIMD simulations. The BAs-ZnO and BP-ZnO heterostructures are semiconductors with direct band gaps of 1.43 eV and 2.35 eV, respectively, and they exhibit type-I band alignment, which make them suitable for light emission applications with the ultra-fast recombination between electrons and holes. Both the BAs-ZnO and BP-ZnO heterostructures can exhibit a wider optical absorption range for visible-light owing to their reduced band gaps compared with the isolated BAs, BP and ZnO monolayers. The band alignment of both the BAs-ZnO and BP-ZnO heterostructures can straddle the water redox potential and they would have better performances owing to the direct band gap and the reduced band gap. All these findings demonstrate that the BX-ZnO heterostructures can be considered as potential photocatalysts for water splitting.

Electronic and photocatalytic properties of two-dimensional boron phosphide/SiC van der Waals heterostructure with direct type-II band alignment: a first principles study.

Designing van der Waals (vdW) heterostructures of two-dimensional materials is an efficient way to realize amazing properties as well as opening opportunities for applications in solar energy conversion and nanoelectronic and optoelectronic devices. In this work, we investigate the electronic, optical, and photocatalytic properties of a boron phosphide-SiC (BP-SiC) vdW heterostructure using first-principles calculations. The relaxed configuration is obtained from the binding energies, inter-layer distance, and thermal stability. We show that the BP-SiC vdW heterostructure has a direct band gap with type-II band alignment, which separates the free electrons and holes at the interface. Furthermore, the calculated absorption spectra demonstrate that the optical properties of the BP-SiC heterostructure are enhanced compared with those of the constituent monolayers. The intensity of optical absorption can reach up to about 105 cm-1. The band edges of the BP-SiC heterostructure are located at energetically favourable positions, indicating that the BP-SiC heterostructure is able to split water under working conditions of pH = 0-3. Our theoretical results provide not only a fascinating insight into the essential properties of the BP-SiC vdW heterostructure, but also helpful information for the experimental design of new vdW heterostructures.

Airflow dynamics of human jets: sneezing and breathing - potential sources of infectious aerosols.

Natural human exhalation flows such as coughing, sneezing and breathing can be considered as 'jet-like' airflows in the sense that they are produced from a single source in a single exhalation effort, with a relatively symmetrical, conical geometry. Although coughing and sneezing have garnered much attention as potential, explosive sources of infectious aerosols, these are relatively rare events during daily life, whereas breathing is necessary for life and is performed continuously. Real-time shadowgraph imaging was used to visualise and capture high-speed images of healthy volunteers sneezing and breathing (through the nose - nasally, and through the mouth - orally). Six volunteers, who were able to respond to the pepper sneeze stimulus, were recruited for the sneezing experiments (2 women: 27.5±6.36 years; 4 men: 29.25±10.53 years). The maximum visible distance over which the sneeze plumes (or puffs) travelled was 0.6 m, the maximum sneeze velocity derived from these measured distances was 4.5 m/s. The maximum 2-dimensional (2-D) area of dissemination of these sneezes was 0.2 m(2). The corresponding derived parameter, the maximum 2-D area expansion rate of these sneezes was 2 m(2)/s. For nasal breathing, the maximum propagation distance and derived velocity were 0.6 m and 1.4 m/s, respectively. The maximum 2-D area of dissemination and derived expansion rate were 0.11 m(2) and 0.16 m(2)/s, respectively. Similarly, for mouth breathing, the maximum propagation distance and derived velocity were 0.8 m and 1.3 m/s, respectively. The maximum 2-D area of dissemination and derived expansion rate were 0.18 m(2) and 0.17 m(2)/s, respectively. Surprisingly, a comparison of the maximum exit velocities of sneezing reported here with those obtained from coughing (published previously) demonstrated that they are relatively similar, and not extremely high. This is in contrast with some earlier estimates of sneeze velocities, and some reasons for this difference are discussed.