Search

Planetary boundary layer (PBL) modeling is a primary contributor to uncertainties in a numerical weather prediction (NWP) model due to difficulties in modeling the turbulent transport of surface fluxes. The Weather Research and Forecasting model (WRF) has provided many PBL schemes that may feature a non‐local transport component driven by large eddies or a one‐and‐half order turbulence closure model, but few of them possess the two features at once. In the present study, a turbulent kinetic energy (TKE)‐based eddy diffusivity/viscosity method is integrated into the non‐local Asymmetric Convective Model version 2 (ACM2) PBL scheme and implemented in WRF. The original first‐order eddy‐diffusivity term in ACM2 is discarded and an extra prognostic equation for TKE, which considers the tendency of TKE by buoyancy, wind shear, vertical transport, and dissipative processes, is supplied to calculate the diffusivity/viscosity. Non‐local transport is modeled the same as ACM2 using the transilient matrix method. Idealized tests using prescribed surface heat flux and roughness length are performed. TKE‐ACM2 displays advantages over the PBL scheme developed by Bougeault and Lacarrère (hereinafter referred to as Boulac) and ACM2 in the wind speeds (WS) profile because it better matches large‐eddy simulations results in the surface momentum flux. Real case simulations show that TKE‐ACM2 generally outperforms in the diurnal vertical profiles of WS under stable conditions. TKE‐ACM2 also produces a better alignment under moderately unstable conditions in the early nighttime at the urban LiDAR station. However, the model exhibits discrepancies more apparently under a more unstable condition during the winter daytime. Plain Language Summary: Large uncertainties in a numerical weather prediction (NWP) model arise from difficulties in accurately modeling the planetary boundary layer because of the chaotic motions of air. An adequate representation of vertical turbulent mixing processes in an NWP model usually requires the consideration of turbulent transport due to large‐scale buoyant plumes and a realistic while efficient turbulence closure model. The widely used NWP model, the Weather Research and Forecasting model, offers several algorithms to represent the turbulent transport of scalars and momentum in the PBL, but further developments are needed for particular schemes due to their drawbacks. Furthermore, little investigation has been done to assess the simulated vertical structures of wind speeds mainly constrained by the lack of high spatiotemporal resolution Doppler wind LiDAR data. In this research, we derived a new algorithm for modeling the vertical turbulent mixing processes that is based on the turbulent kinetic energy turbulence closure model. Simulations using idealized and real atmospheric conditions are performed to examine the performance of the new PBL scheme. Key Points: A new non‐local planetary boundary scheme, turbulent kinetic energy (TKE)‐Asymmetric Convective Model version 2 (ACM2), based on the TKE is proposed and evaluated with large‐eddy simulations (LES) and observationsIdealized simulations are conducted for TKE‐ACM2 to examine its sensitivity to key parameters including the weighting factor between local and non‐local fluxes and turbulent Prandtl number. Furthermore, it is shown that TKE‐ACM2 aligns better with LES results than ACM2 and Boulac under a prescribed convective conditionHigh spatiotemporal resolution Doppler LiDAR observations are used to evaluate the performance of the new scheme over the summer and winter seasons in Hong Kong. TKE‐ACM2 shows improvements over ACM2, particularly under stable conditions. TKE‐ACM2 also predicts the surface wind speeds considerably more accurately than other schemes at the urban stations in the summer case simulation [ABSTRACT FROM AUTHOR]

There are an estimated 1 billion cases of superficial fungal infection globally. Fungal pathogens form biofilms within wounds and delay the wound healing process. Miconazole and terbinafine are commonly used to treat fungal infections. They induce the accumulation of reactive oxygen species (ROS) in fungi, resulting in the death of fungal cells. ROS are highly reactive molecules, such as oxygen (O2), superoxide anion (O2•−), hydrogen peroxide (H2O2) and hydroxyl radicals (•OH). Although ROS generation is useful for killing pathogenic fungi, it is cytotoxic to human keratinocytes. To the best of our knowledge, the effect of miconazole and terbinafine on HaCaT cells has not been studied with respect to intracellular ROS stimulation. We hypothesized that miconazole and terbinafine have anti-wound healing effects on skin cells when used in antifungal treatment because they generate ROS in fungal cells. We used sulforhodamine B protein staining to investigate cytotoxicity and 2′,7′-dichlorofluorescein diacetate to determine ROS accumulation at the 50% inhibitory concentrations of miconazole and terbinafine in HaCaT cells. Our preliminary results showed that topical treatment with miconazole and terbinafine induced cytotoxic responses, with miconazole showing higher cytotoxicity than terbinafine. Both the treatments stimulated ROS in keratinocytes, which may induce oxidative stress and cell death. This suggests a negative correlation between intracellular ROS accumulation in keratinocytes treated with miconazole or terbinafine and the healing of fungi-infected skin wounds. [ABSTRACT FROM AUTHOR]

Objective: To compare predictive validity of the Wilson Sims Fall Risk Assessment Tool (WSFRAT) with that of the Morse Fall Scale (MFS) in psychogeriatric inpatients. Methods: Psychogeriatric patients from Shatin Hospital, Tai Po Hospital, Castle Peak Hospital, and United Christian Hospital who had fall incident between April 2019 and April 2020 were identified. Their fall risks were assessed by the WSFRAT and the MFS, and their falls incidents during hospitalisation were recorded. Patients were classified as having high fall risk when their MFS score was ≥45 and when their WSFRAT score was ≥7. Sensitivity, specificity, and positive and negative predictive values of the two scales were calculated. Results: We identified 183 (90 male and 93 female) psychogeriatric patients aged ≥65 years who had fall incident and were assessed by both the WSFRAT and the MFS during the study period. Among the 183 patients, four sustained a fall during hospital stay, giving a prevalence of 2.19%. All four patients were classified as having high risk of fall by WSFRAT, but only two of them were classified so by MFS. The sensitivity of WSFRAT was 100%, which was higher than the 50% by MFS, but specificity of MFS was higher than that of WSFRAT (45.81% vs 54.75%). Conclusion: WSFRAT is a better fall risk assessment scale for psychiatric inpatients than MFS, because of higher sensitivity (100% vs 50%). It has items specific to psychiatric patients and should replace MFS in psychiatric settings. [ABSTRACT FROM AUTHOR]

Conductive atomic force microscopy (C-AFM) and surface photovoltage (SPV) microscopy were used to investigate local electronic structure in p-type GaN. C-AFM imaging revealed locally reduced forward- and reverse-bias conductivity near threading dislocations. In addition, regions near threading dislocations demonstrated significantly enhanced surface photovoltage response when compared to regions away from dislocations. Analytical treatment of the surface photovoltage as a function of pertinent material properties indicated that reduced background dopant concentration is the most likely cause for the increased SPV. Both reduced conductivity and enhanced surface photovoltage are shown to be consistent with Mg segregation to dislocation cores that results in regions of locally decreased electrically active Mg concentration surrounding the dislocations. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The optical properties of undoped and modulation-doped A1GaN/GaN single heterostructures (SHs) grown by metalorganic chemical vapor deposition are investigated at low temperature using photoluminescence measurements. The formation of a two-dimensional electron gas at the heterojunction is verified by temperature-dependent Hall mobility and 300 K capacitance-voltage measurements. Radiative recombination is observed between the electrons in two-dimensional quantum states at the heterointerface and the holes in the flat-band region or bound to residual acceptors both in undoped and modulation-doped A1GaN/GaN SHs. These peaks disappear when the top A1GaN layer is removed by reactive ion etching. In addition, the photoluminescence results under different laser excitation intensity and lattice temperature are also described for undoped and modulation-doped A1GaN/GaN SHs with various A1 compositions and growth interrupt times. c 2001 American Institute of Physics. [DOI: 10.1063/1.1330767]. [ABSTRACT FROM AUTHOR]

Objectives: Development of a fall prevention programme for psychogeriatric inpatients is required. Therefore, the present study aimed to investigate factors associated with falls in psychogeriatric inpatients and compare two fall risk assessment tools. Methods: This study had two parts. First, all fall reports involving psychogeriatric inpatients in United Christian Hospital in 2016 were retrospectively reviewed. Factors associated with the falls were identified by comparing patients who had a fall incident and those who did not. Second, in a pilot study, 30 consecutive psychogeriatric inpatients were assessed for fall risk using the Morse Fall Scale (MFS) and the Wilson Sims Fall Risk Assessment Tool (WSFRAT), and outcomes were then compared with the modified Functional Ambulation Classification (MFAC). Results: In 2016, 46 women and 47 men aged 65 to 94 years were admitted to the psychiatric wards (two women and two men were admitted twice). A total of 12 falls involving nine women and two men were reported. Over 66% of falls involved patients with dementia, 75% involved women, and over 50% occurred on the way to the bathroom, mostly during the night shift when the staffing level was low. In the pilot study, of 30 consecutive psychogeriatric inpatients, 20 were classified as high risk by the WSFRAT and 10 of them were also classified as high risk by the MFS. Those classified as high risk by WSFRAT matched perfectly with those classified as high risk by MFAC. However, 30% of those classified as high risk by MFAC were not classified as high risk by MFS. Conclusions: Patients with dementia and women had higher risk of fall. Extra proportion of at-risk patients are able to benefit from additional fall risk interventions when WSFRAT is used instead of MFS. Further studies are needed to calculate the psychometric properties of WSFRAT. [ABSTRACT FROM AUTHOR]