Impact Of Negative Pressure Research Articles

The Effects of Negative Pressure Therapy on Hair Growth of Mouse Models.

Negative pressure therapy (NPT) has been shown to facilitate wound healing and promote hair growth in a porcine model. However, there is a paucity of research on the impact of negative pressure on hair growth in murine models. Despite the ability of nude mice to develop hair follicles, the hair they produce is often flawed towing to genetically induced keratin disorders, rendering them a pertinent animal model for assessing hair regeneration. Therefore, this study aims to investigate the effects of negative pressure on hair follicle growth in a nude mouse model. To achieve this, a customized external tissue expansion device was developed to apply negative pressure to the dorsum of nude mice. The mice were subjected to several treatment courses consisting of 15 and 30 min of continuous negative pressure at 10 mmHg, which were repeated 5 and 10 times every other day until sacrifice. Dorsal skin samples were subsequently extracted from the suction and nonsuction areas. The sections were stained with various antibodies to assess the expression of SOX-9, LHX-2, Keratin-15, β-catenin, CD31, and vascular endothelial growth factor-A, and a TUNEL assay was used to analyze cell apoptosis. The results showed that the number of hair follicles and angiogenesis were significantly higher in the suction area than in the nonsuction area in all groups. Moreover, mice that received NPT for 15 min for 10 times had a higher hair follicle density than the other three groups. Immunofluorescence staining for LHX-2 and Keratin 15 further validated the results of these findings. In conclusion, this study demonstrated that negative pressure effectively promotes hair follicle growth and angiogenesis in nude mice through SOX-9- and LHX-2-mediated follicular regeneration and β-catenin-mediated hair follicle morphogenesis.

Aerosol Retention Barriers.

Aerosol Retention Barriers.

The influence of nanostructure on the wetting transition of polyvinylidene fluoride nanoweb: from the petal effect to the lotus effect

In this study, the effects of the surface structure of electrospun polyvinylidene fluoride (PVDF) nanoweb on surface wettability were analyzed. The conditions of the surface structure representing the lotus and petal effects were derived, and the difference in the dynamic behavior of the water droplets on the surfaces was investigated. To this end, a PVDF nanoweb was fabricated by electrospinning various concentrations of PVDF solutions. The nanoscale roughness was adjusted by varying the CF4 plasma etching time. It was seen that when the concentration of the electrospun PVDF solution was 15 or 20 wt%, a hierarchical structure of microbeads and nanofibers was formed. In the 20 wt% nanoweb, droplets formed an apparent contact angle of 149.5 ± 2.2°, and the petal effect was observed in which the droplets were pinned on the surface and did not roll off even when the nanoweb was tilted by 180°. As a result of introducing fine nanostructures with CF4 plasma etching on the 20 wt% nanoweb, the apparent contact angle increased to 162.8–164.4°, and the shedding angle decreased to 5.3–8.1°, showing a wetting transition to the lotus effect, regardless of the plasma etching time. In addition, the lotus effect was observed when 15 wt% nanoweb was treated with CF4 plasma etching for more than 10 min. We confirmed that the lotus effect was exhibited when the three-phase contact line of the PVDF nanoweb/water/air was discontinuous, and the contact area between the surface and the water droplets was reduced with increased air pockets at this interface, which led to a decrease in the adhesive force and the impact of negative pressure.

Renovation in hospitals: a case study on the use of control cubes for local repairs in health-care facilities

PurposeThe purpose of this study is to evaluate the effectiveness of the control cubes for dust control in health-care facilities. Research shows that more than 80% of pathogenic agents in hospitals are spread into the air, where they either remain airborne or deposit on the surface. At the same time, renovation and repair activities, including regular maintenance, are a necessity in active health-care facilities and a multitude of studies have documented their impact on indoor air quality. The dust that is generated by construction activities may potentially carry pathogenic agents, varying from coarse particles (≤10 µm, PM10) to fine particles (≤2.5 µm, PM2.5), including airborne bacteria, and fungal spores linked to high patient mortality in immune-compromised patients.Design/methodology/approachThis study measures the impact and effectiveness of one such preventative measure, namely, the control cube (CC), on air quality during renovation and repair. CC is a temporary structure, typically made from stainless steel, around the local repair zone to minimize the spread of dust and potential microorganisms. The current paper presents a comparative analysis to identify the effectiveness of a CC equipped with the high-efficiency particulate filtration (HEPA) filter in a hospital setting by simulating construction renovation and repair work.FindingsA baseline was established to measure the effectiveness of CCs and the impact of negative pressure on the indoor air quality in a hospital during simulated renovation work. Results showed that CCs are very effective in minimizing the spread of dust due to construction activities in the hospital. However, it is imperative to ensure that the air inside the CC is cleaned via filtration.Originality/valueCCs are very effective, and this paper investigates the best approach for facility managers to implement this strategy.

Impact of Negative Pressure in a Room Due to Increased Airtightness in Residential Apartment Housing

This study surveyed the impact of a negative pressure in a room in a highly airtight residential apartment with Class 3 ventilation (natural air intake and mechanical exhaust). The results of the study are as follows. 1) A room may reach an excessive level of negative pressure depending on how the ventilation system is used. 2) Noise from the drain pipe of a room air conditioner caused by negative pressure in the room is dependent on how the drain pipe is installed. 3) An experiment was conducted to investigate the mechanism of a seal break in a toilet trap. However, the seal did not break. Thus, seal breaks may be caused by multiple factors.

An effective method for hydrogen production in a single-chamber microbial electrolysis by negative pressure control

In this study, we construct a scalable tubular single-chamber microbial electrolysis cell that using negative pressure (40.52 kPa) to enhance the hydrogen production. The impact of negative pressure on current production, hydrogen recovery, and microbial community of microbial electrolysis cells are investigated. Negative pressure could effectively enhance the hydrogen recovery and inhibit the growth of methanogens. Consequently, the microbial electrolysis cell operated under negative pressure achieves a maximum hydrogen production rate of 7.72 ± 0.06 L L−1 d−1, which is more than four times higher that of reactor running under normal pressure (1.51 ± 0.41 L L−1 d−1). Energy quantification shows that the electrical energy recovery under negative pressure is 146.98%, which is much higher than 95.00% under normal pressure. Therefore, negative pressure control is as effective for increasing hydrogen production and energy recovery in the scalable MEC, and has a great practical application prospect. However, negative pressure cannot knick out methanogens. Once negative pressure is removed, methanogens will quickly take over and after that applying negative pressure again can only partly inhibit methane production.