•A weighting function for integration of spectral coherence is proposed.•Periodicity of the spectral coherence along cyclic frequency is exploited to define weighting function.•The method does not ...require the knowledge of fault frequency.
Envelope analysis plays an essential role in fault diagnostics of rotating machinery. One popular method to attain the envelope spectrum is to integrate the spectral coherence over a chosen spectral frequency band. Considering the recently developed algorithm for fast estimation of spectral coherence, the present study proposes a weighting function used for the integration. Noting that the spectral coherence for a cyclostationary signal appears with a periodic pattern along the cyclic frequency axis, the weighting function is designed by calculating the autocorrelation over the cyclic frequency domain of the spectral coherence. This improves the envelope spectrum estimation, as spectral bands with high autocorrelations are amplified in the course of integration. Without consideration of fault characteristics, the proposed idea alleviates the burden of selecting the frequency band for integration. Experimental measurements from the cavitating propeller and faulty bearing demonstrate its usage in challenging scenarios such as noisy situations or multiple types of faults.
•Decomposition of spectral coherence using nonnegative matrix factorization is attempted to obtain envelope spectrum.•The decomposition is further enhanced by applying regularization with sparse ...constraint.•Systematic way of choosing the number of clusters is also suggested.•Both simulations and experiments verify the effectiveness.
Integration of the spectral coherence over the domain of spectral frequency is one popular way for reaching the envelope spectrum which is an indispensable tool for the fault diagnosis of rotating machineries. Envelope spectrum can be enhanced by introducing a decomposition of spectral coherence with the aid of nonnegative matrix factorization frequently exploited for the data clustering. Based on this regime, the present study aims to deal with further improvement of the envelope spectrum by taking two major considerations. First, it is to impose a sparsity constraint to the minimization problem treated in the standard NMF, eventually allowing a sparse representation of the envelope spectrum. By taking advantage of a randomness of NMF solution, the second is to establish how to correctly choose the number of clusters, a prerequisite for starting the NMF algorithm. Finally, the suggested method is verified throughout a synthetic data and experimental measurement from propeller cavitation.
Background
Recently, autologous platelet‐rich plasma (PRP) has attracted attention in various medical fields, including plastic and orthopedic surgery and dermatology, for its ability to promote ...wound healing. PRP has been tested during facelift and hair transplantation to reduce swelling and pain and to increase hair density.
Objective
To investigate the effects of PRP on hair growth using in vivo and in vitro models.
Methods
PRP was prepared using the double‐spin method and applied to dermal papilla (DP) cells. The proliferative effect of activated PRP on DP cells was measured. To understand the mechanisms of activated PRP on hair growth, we evaluated signaling pathways. In an in vivo study, mice received subcutaneous injections of activated PRP, and their results were compared with control mice.
Results
Activated PRP increased the proliferation of DP cells and stimulated extracellular signal‐regulated kinase (ERK) and Akt signaling. Fibroblast growth factor 7 (FGF‐7) and beta‐catenin, which are potent stimuli for hair growth, were upregulated in DP cells. The injection of mice with activated PRP induced faster telogen‐to‐anagen transition than was seen on control mice.
Conclusions
Although few studies tested the effects of activated PRP on hair growth, this research provides support for possible clinical application of autologous PRP and its secretory factors for promotion of hair growth.
Difference-Frequency MUSIC for DOAs Park, Yongsung; Lee, Jeung-Hoon; Gerstoft, Peter
IEEE signal processing letters,
01/2022, Letnik:
29
Journal Article
Recenzirano
The direction-of-arrivals (DOAs) of plane waves in a high-frequency region are estimated without spatial aliasing using multi-frequency processing. The method exploits the difference frequency (DF), ...the difference between two high frequencies. This enables processing data in a feasible region without spatial aliasing. We analyze DOA characteristics upon DF processing and propose a MUSIC-based method dealing with multi-DF and multi-snapshot. Multiple DFs having the same frequency difference allow processing multi-DF equivalently to multi-snapshot. We propose a method that considers all DFs and snapshots jointly and a joint DF method providing a single snapshot DF-MUSIC that does not require stationary DOAs. Numerical examples validate the effectiveness of the proposed method and its DOA performance is discussed.
A precise evaluation of propeller cavitation inception is imperative in prediction of ship's underwater radiated noise performance. In addition to a simple indication on whether the cavitation has ...occurred or not, it would be much more valuable if the location of cavitation occurrence can be identified for a further confirmation. Hence, this work concentrates on establishing an efficient acoustic localization for incipient cavitation using the compressive sensing (CS) theory. Rather than the convex minimization approach, the greedy-type orthogonal matching pursuit (OMP) algorithm is chosen for solving the CS localization problem due to a low computational complexity making it suitable for online applications. It is also proposed to employ the singular value decomposition (SVD) - based rank estimation for a provision of user input parameter that is essential for initializing the greedy algorithm. The suggested localization procedure is validated through the propeller cavitation data obtained in a water tunnel facility.
•Acoustic localization for incipient cavitation is treated by using compressive sensing theory.•Singular-value-decomposition based rank estimation is incorporated to initialize the greed-type algorithm.•The proposed method is verified by experimental measurements in water cavitation tunnel.
The accurate modeling of the complex dynamic stiffness of inflated rubber diaphragms in pneumatic springs is necessary for an efficient design of vibration isolation tables for precision instruments, ...such as optical devices and nano-scale equipment. In addition to pressurized air, rubber diaphragms, essentially employed for the prevention of air leakage, make a significant contribution to the total complex stiffness. To reflect the effect of the dynamic stiffness of the inflated rubber diaphragm on the total complex stiffness during the initial design or design improvement stage, it is desirable to predict the complex stiffness of the inflated rubber diaphragm beforehand. In this paper, an estimation method for the complex stiffness of inflated rubber diaphragms using the commercial finite element method (e.g., ABAQUS) is proposed. The proposed method reflects their dynamic characteristics under the large static deformation by the Mooney–Rivlin and Morman’s constitutive equations. The results of comparison with experimental results indicate that the predictions obtained by the proposed method are congruent with the experimental values of the diaphragm.
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•Au-Ag-PDA@STCM NPs significantly inhibited sebaceous gland cell proliferation.•Au-Ag-PDA@STCM NPs had a stronger antiproliferative effect than Au-Ag@PDA NPs.•Photothermal therapy for ...30 days with Au-Ag-PDA@STCM NPs caused no significant tissue damage.
The polydopamine coating on Au-Ag nanoparticles (Au-Ag-PDA) possess excellent photothermal conversion efficiency after absorbing near-infrared laser light. After the stem cell membrane (STCM) encapsulates Au-Ag-PDA (Au-Ag-PDA@STCM), the nanoparticles (NPs) exhibit less cytotoxicity, and further optimizing their efficiency in photothermal therapy. The photothermal activity of Au-Ag-PDA@STCM has not yet been reported. Therefore, in this study, the sebaceous gland cell line SZ95 and the golden hamsters were used to observe the photothermal effects of the Au-Ag-PDA@STCM. SZ95 cells were treated with various concen-trations of Au-Ag-PDA@STCM NPs. The photothermal effect on cell proliferation was analyzed after irradiating the cells with a 808 nm laser. After laser treatment of golden hamsters, the flank organs were observed at 4 different time points. Histological analysis was performed to observe tissue damage. The results suggest that Au-Ag-PDA@STCM NPs significantly inhibited the proliferation of sebaceous gland cells in vitro, and reduced the size of sebaceous glands and sebum secretion in vivo. Therefore, NPs can be used to treat acne by thermally injuring sebaceous gland cells.
S100A9 and S100A8 are called damage‐associated molecular pattern (DAMP) molecules because of their pro‐inflammatory properties. Few studies have evaluated S100A9 and S100A8 function as DAMP molecules ...in atopic dermatitis (AD). We investigated how house‐dust mites affect S100A9 and S100A8 expression in Th2 cytokine‐ and Th17 cytokine‐treated keratinocytes, and how secretion of these molecules affects keratinocyte‐derived cytokines. Finally, we evaluated expression of these DAMP molecules in AD patients. S100A9 expression and S100A8 expression were strongly induced in IL‐17A‐ and Dermatophagoides (D.) farinae‐treated keratinocytes, respectively. Furthermore, co‐treatment with D. farinae and IL‐17A strongly increased expression of S100A9 and S100A8 compared with D. farinae‐Th2 cytokine co‐treatment. The IL‐33 mRNA level increased in a dose‐dependent manner in S100A9‐treated keratinocytes, but TSLP expression did not change. S100A8/A9 levels were also higher in the lesional skin and serum of AD patients, and correlated with disease severity. Taken together, S100A9 and S100A8 may be involved in inducing DAMP‐mediated inflammation in AD triggered by IL‐17A and house‐dust mites.
The scaffolding adaptor protein p62/SQSTM1 (p62) has been shown to be an autophagy receptor that acts as a link between the ubiquitination and autophagy machineries. However, the roles of autophagy ...and p62 in human keratinocytes are not well understood. In this study, we show that keratinocyte autophagy negatively regulates p62 expression, which is essential for the prevention of excessive inflammation and the induction of cathelicidin in human keratinocytes. Stimulation of TLR2/6 or TLR4 in primary human keratinocytes robustly activated autophagy pathways and up-regulated p62 expression through induction of NADPH oxidases 2 and 4 and the generation of reactive oxygen species. MyD88 and TNFR-associated factor 6, key signaling molecules that mediate TLR activation, played an essential role in the induction of autophagy and p62 expression. Additionally, blockade of autophagy significantly increased the generation of inflammatory cytokines and expression of p62 in primary human keratinocytes. Notably, silencing hp62 through RNA interference resulted in a significant decrease in NF-κB activation, inflammatory cytokine production, cathelicidin expression, and cell proliferation (as well as cyclin D1 expression) in keratinocytes. Epidermal expression of p62 was further found to be significantly higher in psoriatic skin than in skin affected by atopic dermatitis or from healthy controls. Collectively, our data provide new insights into the roles of autophagy and p62 in controlling cutaneous inflammation.
Vitamin D plays an important role in the immune system, and its deficiency has been implicated in various skin diseases, including atopic dermatitis and psoriasis. Acne is a common inflammatory skin ...disease; however, the association with vitamin D remains unclear.
We evaluated vitamin D levels in patients with acne to determine the effect of vitamin D supplementation.
This study included 80 patients with acne and 80 healthy controls. Serum 25-hydroxyvitamin D (25(OH)D) levels were measured, and demographic data were collected. Vitamin D-deficient patients were treated with oral cholecalciferol at 1000 IU/day for 2 months.
Deficiency in 25(OH)D was detected in 48.8% of patients with acne, but in only 22.5% of the healthy controls. The level of 25(OH)D was inversely associated with the severity of acne, and there was a significant negative correlation with inflammatory lesions. In a subsequent trial, improvement in inflammatory lesions was noted after supplementation with vitamin D in 39 acne patients with 25(OH)D deficiency.
Limitations of the study include the small number of patients in the supplementation study and the natural fluctuation of acne.
Vitamin D deficiency was more frequent in patients with acne, and serum 25(OH)D levels were inversely correlated with acne severity, especially in patients with inflammatory lesions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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