Effect of the gel elasticity of model skin matrices on the distance/depth-dependent transmission of vibration energy supplied from a cosmetic vibrator.

OBJECTIVE: The purpose of this study was to determine how the energies supplied from a cosmetic vibrator are deeply or far transferred into organs and tissues, and how these depths or distances are influenced by tissue elasticity. METHODS: External vibration energy was applied to model skin surfaces through a facial cleansing vibrator, and we measured a distance- and depth-dependent energy that was transferred to model skin matrices. As model skin matrices, we synthesized hard and soft poly(dimethylsiloxane) (PDMS) gels, as well as hydrogels with a modulus of 2.63 MPa, 0.33 MPa and 21 kPa, respectively, mostly representing those of skin and other organs. The transfer of vibration energy was measured either by increasing the separation distances or by increasing the depth from the vibrator. RESULTS: The energies were transmitted deeper into the hard PDMS than into the soft PDMS and hydrogel matrices. This finding implies that the vibration forces influence a larger area of the gel matrices when the gels are more elastic (or rigid). There were no appreciable differences between the soft PDMS and hydrogel matrices. However, the absorbed energies were more concentrated in the area closest to the vibrator with decreasing elasticity of the matrix. Softer materials absorbed most of the supplied energy around the point of the vibrator. In contrast, harder materials scattered the external energy over a broad area. CONCLUSIONS: The current results are the first report in estimating how the external energy is deeply or distantly transferred into a model skins depending on the elastic moduli of the models skins. In doing so, the results would be potentially useful in predicting the health of cells, tissues and organs exposed to various stimuli.

11ß-hydroxysteroid dehydrogenase type 1 is expressed in human sebaceous glands and regulates glucocorticoid-induced lipid synthesis and toll-like receptor 2 expression in SZ95 sebocytes.

BACKGROUND: Glucocorticoids (GCs) affect the pathophysiology of sebaceous glands, causing development or exacerbation of acne. The availability of GCs is regulated by isoenzymes of 11ß-hydroxysteroid dehydrogenase (11ßHSD) at tissue-specific levels. 11ßHSD type 1 (HSD11ß1) is a reductase, catalysing the conversion of cortisone to active cortisol, and is highly expressed in liver and adipose tissue. Recently, HSD11ß1 was observed in human skin in keratinocytes and fibroblasts. OBJECTIVES: To investigate the expression of HSD11ß1 in sebaceous glands of normal and acne-involved skin, and to examine the role of HSD11ß1 in GC-induced lipid synthesis and toll-like receptor 2 (TLR2) expression in sebocytes. METHODS: Expression of HSD11ß1 was examined by immunohistochemistry in acne lesional skin and normal skin of healthy volunteers. The cultured SZ95 sebocytes were treated with dexamethasone, and the lipid synthesis and mRNA levels of sterol regulatory element binding protein 1 (SREBP-1) and TLR2 were determined. Use of an HSD11ß1 inhibitor and the small interference RNA (siRNA) approach were used to investigate the role of HSD11ß1 on the GC regulation of sebocyte functions. RESULTS: HSD11ß1 was expressed in human sebaceous glands and upregulated in acne lesional skin. HSD11ß1 mRNA was enhanced by dexamethasone and cytokines in SZ95 sebocytes. Dexamethasone enhanced lipid synthesis, partially through the transcriptional induction of SREBP-1, and also by increasing TLR2 mRNA levels. Inhibition of HSD11ß1 by PF-915275 or siRNA significantly inhibited the GC-induced lipid synthesis and the mRNA expression of SREBP-1 and TLR2. CONCLUSIONS: Our results indicate that HSD11ß1 plays a key role in the modulation of GC action on sebocytes, including sebum production and TLR2-mediated inflammation, thereby influencing the pathogenesis of acne.

Enhancing flexible fiber filter (3FM) performance using in-line coagulation.

A new packing for deep bed filtration using Flexible Fibers has been proposed and developed on a very large scale for tertiary treatment of wastewater. The purpose of this study is to check the possibility of using this technology for the production of drinking water from surface water. In this study, the feasibility of the fiber filter application on water treatment was examined and the removal efficiency of fiber filter was improved using an in-line coagulant injection method. The experiments were carried out at pilot scale. The filter was packed with bundles of polyamide fibers with a bed porosity of 93%. Nak-dong River was used as the filter influent water and alum, PSOM, and PAC were used as the coagulants. The coagulants were injected by the in-line injection method. Small dosages (1-5 mg/L) of the polymeric coagulants (PSOM and PAC) showed an increase of removal efficiency compared to the operation without coagulants. Specifically, 1 mg/L of PAC showed the longest filtration time. Considering filtration time, filtrate quality, and filtered volume, the filtration velocity of 120 m/hr was chosen as an optimum value. For long-term operations, the effluent quality was 0.4 NTU and the removal efficiency was stable for the given optimum conditions.

A Fourier transform-based sidelobe reduction method in ultrasound imaging.

Focusing is widely used to increase the resolution in medical ultrasound imaging systems. Focusing increases signal levels returning from the mainlobe direction and decreases those from sidelobe directions. The sidelobes, when not completely cancelled, deteriorate the resulting image resolution. This paper proposes a method of improving the resolution by scaling the received signal according to the ratio between the mainlobe and the sidelobe levels computed in the frequency domain by the use of Fourier transform. The proposed method is verified by computer simulation and experiment and is shown to be highly effective in narrowing the mainlobe width and decreasing the sidelobe levels at the same time.

A study of synthetic-aperture imaging with virtual source elements in B-mode ultrasound imaging systems.

We propose an all point transmit and receive focusing method based on transmit synthetic focusing combined with receive dynamic focusing in a linear array transducer. In the method, on transmit, a virtual source element is assumed to be located at the transmit focal depth of conventional B-mode imaging systems, and transmit synthetic focusing is used in two half planes, one before and the other after the transmit focal depth, using the RF data of each scanline, together with all other relevant RF scanline data previously stored. The proposed new method uses the same data acquisition scheme as the conventional focusing method while maintaining the same frame rate via high-speed signal processing, but it is not suitable for imaging moving objects. It improves upon the lateral resolution and sidelobe level at all imaging depths. Also, it increases the transmit power and image signal-to-noise ratio (SNR), due to transmit field synthesis, and extends the image penetration depth as well. Evaluations with simulation and experimental data show much improvement in resolution and SNR at all imaging depths.

Realization of sinc waves in ultrasound imaging systems.

It is known that the transmit pulse waveforms of a limited-diffraction beam in a linear array transducer should be varied according to transducer element location, dictating the use of sophisticated hardware. In order to overcome this disadvantage while achieving the same field response, we propose a method of synthesizing limited-diffraction beams by combined signal processing of pulsed plane waves propagating in distinct directions over several consecutive insonification time intervals. The method is capable of achieving both higher transmit power and better lateral resolution over a larger depth of field. Although its field response is not uniform throughout the imaging points, this is not a major problem since the response is quite uniform within a region of interest. The proposed method requires the use of multiple insonifications for transmit focusing, and, therefore, can be applied in imaging slowly-moving or still objects. Both simulation and experimental results corroborate its superiority in terms of the lateral resolution at all imaging depths.