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1.
J Cell Sci ; 133(23)2020 12 07.
Article in English | MEDLINE | ID: mdl-33148612

ABSTRACT

SMARCA2, an evolutionarily conserved catalytic ATPase subunit of SWI/SNF complexes, has been implicated in development and diseases; however, its role in mammalian ovarian function and female fertility is unknown. Here, we identified and characterized the 3'-UTR of the porcine SMARCA2 gene and identified a novel adenylate number variation. Notably, this mutation was significantly associated with sow litter size traits and SMARCA2 levels, due to its influence on the stability of SMARCA2 mRNA in ovarian granulosa cells (GCs). Immunohistochemistry and functional analysis showed that SMARCA2 is involved in the regulation of follicular atresia by inhibiting GC apoptosis. In addition, miR-29c, a pro-apoptotic factor, was identified as a functional miRNA that targets SMARCA2 in GCs and mediates regulation of SMARCA2 expression via the NORFA-SMAD4 axis. Although a potential miR-29c-responsive element was identified within NORFA, negative regulation of miR-29c expression by NORFA was not due to activity as a competing endogenous RNA. In conclusion, our findings demonstrate that SMARCA2 is a candidate gene for sow litter size traits, because it regulates follicular atresia and GC apoptosis. Additionally, we have defined a novel candidate pathway for sow fertility, the NORFA-TGFBR2-SMAD4-miR-29c-SMARCA2 pathway.This article has an associated First Person interview with the first author of the paper.


Subject(s)
Apoptosis , Fertility , Follicular Atresia , Granulosa Cells/cytology , MicroRNAs , Transcription Factors/genetics , Animals , Apoptosis/genetics , Female , Fertility/genetics , MicroRNAs/genetics , Swine
2.
Int J Mol Sci ; 23(18)2022 Sep 13.
Article in English | MEDLINE | ID: mdl-36142569

ABSTRACT

In mammals, female fertility is determined by the outcome of follicular development (ovulation or atresia). The TGF-ß/SMAD signaling pathway is an important regulator of this outcome. However, the molecular mechanism by which the TGF-ß/SMAD signaling pathway regulates porcine follicular atresia has not been fully elucidated. Microrchidia family CW-type zinc finger 2 (MORC2) is anovel epigenetic regulatory protein widely expressed in plants, nematodes, and mammals. Our previous studies showed that MORC2 is a potential downstream target gene of the TGF-ß/SMAD signaling pathway. However, the role of MORC2 in porcine follicular atresia is unknown. To investigate this, qRT-PCR, western blotting, and TdT-mediated dUTP nick-end labeling were performed. Additionally, the luciferase activity assay was conductedto confirm that the TGF-ß/SMAD signaling pathway regulates MORC2. Our results demonstrate that MORC2 is animportant anti-apoptotic molecule that prevents porcine follicular atresia via a pathway involving mitochondrial apoptosis, not DNA repair. Notably, this studyrevealsthat the TGF-ß/SMAD signaling pathway inhibits porcine granulosa cell apoptosis by up-regulating MORC2. The transcription factor SMAD4 regulated the expression of MORC2 by binding to its promoter. Our results will help to reveal the mechanism underlying porcine follicular atresia and improve the reproductive efficiency of sows.


Subject(s)
Follicular Atresia , Granulosa Cells , Animals , Female , Follicular Atresia/genetics , Granulosa Cells/metabolism , Luciferases/metabolism , Mammals/metabolism , Signal Transduction , Swine , Transcription Factors/metabolism , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolism
3.
Yeast ; 38(11): 601-611, 2021 11.
Article in English | MEDLINE | ID: mdl-34486746

ABSTRACT

Our previous study revealed that N-acetyl-l-cysteine (NAC) could enhance the secretion of recombinant proteins by Pichia pastoris, but the corresponding molecular mechanisms are still unclear. In the present study, we explored whether other thiols have a similar action on the secretion of recombinant human serum albumin and porcine follicle-stimulating hormone fusion protein (HSA-pFSHß), to reveal the mechanism of NAC on HSA-pFSHß secretion. Transcriptome analysis showed that genes involved in oxidoreductase activity and oxidation-reduction process were upregulated in cells supplemented with NAC. The other three thiol-reducing regents including dimercaptopropanol (DT), thioglycolic acid, and mercaptolactic acid could improve HSA-pFSHß production in the culture supernatant. Among them, only DT had similar effect as NAC on HSA-pFSHß secretion and the increase of GSH content. Moreover, 1-20 mM GSH, 1-10 mM cysteine, or 1-20 mM N-acetyl-d-cysteine supplementation could improve the secretion of HSA-pFSHß. Furthermore, 0.4-3.2 mM ethacrynic acid, rather than 1-16 mM BSO could inhibit the effect of NAC on the production of HSA-pFSHß. These results indicated that NAC improved the secretion of HSA-pFSHß by increasing the intracellular GSH content through its thiol activity rather than as a precursor for GSH synthesis. In conclusion, our results demonstrate, for the first time, that the secretion of recombinant HSA-pFSHß in Pichia pastoris could be improved through thiol-reducing agent supplementation, and the mechanism of the effect NAC has on HSA-pFSHß secretion is associated with improving the intracellular GSH content.


Subject(s)
Acetylcysteine , Serum Albumin , Acetylcysteine/pharmacology , Animals , Follicle Stimulating Hormone , Humans , Pichia/genetics , Saccharomycetales , Swine
4.
Appl Opt ; 60(30): 9269-9279, 2021 Oct 20.
Article in English | MEDLINE | ID: mdl-34807074

ABSTRACT

The imaging of a large area scene is difficult to achieve for a single camera. Alternatively, a virtual large aperture can be synthesized by sub-aperture cooperation. We propose a solution through the combination of a coded aperture snapshot spectral imager and coprime array. This method reduces the amount of data by using a smaller sub-aperture for sampling. The position of the sub-aperture is determined according to the element distribution of the coprime array, so that the data obtained from each sampling are about the target object and its adjacent area, which can ensure high reconstruction accuracy. The feasibility of coprime sub-aperture sampling is verified by numerical simulation.

5.
Sensors (Basel) ; 20(16)2020 Aug 12.
Article in English | MEDLINE | ID: mdl-32806605

ABSTRACT

In computational ghost imaging, a spatial light modulator (SLM) can be used to modulate the light field. The relative locations and the number of light point pixels on an SLM affect the imaging quality. Usually, SLMs are two-dimensional arrays which are drawn uniformly or are randomly sparse. However, the patterns formed by a uniform array are periodic when the number of light point pixels is small, and the images formed by a random sparse array suffer from large background noise. In this paper, we introduce a coprime array based on the Eisenstein integer to optimize the light point pixel arrangement. A coprime array is widely used as a microwave radar receiving array, but less implemented in optics. This is the first time that a coprime array based on Eisenstein integer has been introduced in computational ghost imaging. A coprime array with this structure enhances the imaging quality when limited measurements are recorded, and it reduces background noise and avoids periodicity. All results are verified by numerical simulation.

6.
Analyst ; 144(19): 5829-5841, 2019 Oct 07.
Article in English | MEDLINE | ID: mdl-31475698

ABSTRACT

A novel dual-shell magnetic nanoparticle coated with a cationic covalent organic framework, containing ethidium bromide, is easily prepared, characterized and applied as an adsorbent for fast, simple and highly selective capture of nine hydroxylated polycyclic aromatic hydrocarbons in urine samples of non-smokers and smokers who smoked cigarettes with different tar yields. This is the first time that a cationic crystalline framework with high thermal and chemical stability was used for magnetic solid phase extraction. Multiple probes and quantum chemistry theory calculations were conducted to describe the versatile adsorption property directly and quantifiably. A method using high-performance liquid chromatography with a fluorescence detector based on the prepared magnetic adsorbent was established and used to investigate differences in the exposure levels of OH-PAHs in non-smokers and smokers smoking cigarettes with different tar yields. All the OH-PAH analyses present good linearities in the range of 0.1-100 ng mL-1, with R2 > 0.9965. The LOD for the 9 OH-PAHs ranged from 0.0030 to 0.0096 ng mL-1 and the LOQ ranged from 0.096 to 0.030 ng mL-1. The recoveries of the 9 OH-PAHs ranged from 93.3 to 121.3% with the RSD ranging from 0.47 to 3.53%. These results imply that the versatile EB-DS MNPs as adsorbents have great potential in the analysis of trace targets in samples with complex matrices.


Subject(s)
Magnetite Nanoparticles/chemistry , Metal-Organic Frameworks/chemistry , Polycyclic Aromatic Hydrocarbons/urine , Smokers , Adsorption , Chromatography, High Pressure Liquid/methods , Ethidium/chemistry , Humans , Limit of Detection , Polycyclic Aromatic Hydrocarbons/chemistry , Silicon Dioxide/chemistry , Solid Phase Extraction/methods
7.
Opt Express ; 26(16): 20519-20533, 2018 Aug 06.
Article in English | MEDLINE | ID: mdl-30119361

ABSTRACT

The approximate message passing algorithm (AMP) is introduced for practical ghost imaging (GI). This paper proposes to use preconditioning to modified the sensing matrix such that it satisfies the assumptions of the original AMP algorithm. Furthermore, this paper points out that the speckles used in practical GI system are spatially correlated, and this will degrade the imaging performance. The parameter estimations of exponential power distribution reveal that the rows of modified sensing matrix are indeed bounded by the Laplace distribution, which is heavy-tailed. Then, the recovery conditions for such sensing matrix are investigated. Finally, the semi-real experiments and real data processing have validated the proposed imaging method and shown that the required number of measurements for correlated speckles are significantly greater than independent and identically distributed (i.i.d.) measurement. The results of this paper can be used to guide the design of practical GI remote sensing systems.

8.
Opt Express ; 26(1): 99-107, 2018 Jan 08.
Article in English | MEDLINE | ID: mdl-29328297

ABSTRACT

Measurement of fast signal is getting more and more important in many fields. In this paper, we propose to detect a temporal signal based on the idea of computational ghost imaging (GI), which can greatly reduce requirements on bandwidth of detectors. In experiments, we implement retrieving of a temporal signal with time scale of 50ns using a detector of 1kHz bandwidth, which is much lower than the requirement on bandwidth of detector according to information theory. The performance of our technique are also investigated under different detection bandwidths.

9.
Appl Opt ; 56(30): 8430-8435, 2017 Oct 20.
Article in English | MEDLINE | ID: mdl-29091623

ABSTRACT

A direct-vision Amici prism is a desired dispersion element in the value of spectrometers and spectral imaging systems. In this paper, we focus on designing a direct-vision cyclo-olefin-polymer double Amici prism for spectral imaging systems. We illustrate a designed structure: E48R/N-SF4/E48R, from which we obtain 13 deg dispersion across the visible spectrum, which is equivalent to 700 line pairs/mm grating. We construct a simulative spectral imaging system with the designed direct-vision cyclo-olefin-polymer double Amici prism in optical design software and compare its imaging performance to a glass double Amici prism in the same system. The results of spot-size RMS demonstrate that the plastic prism can serve as well as their glass competitors and have better spectral resolution.

10.
Part Fibre Toxicol ; 12: 32, 2015 Oct 24.
Article in English | MEDLINE | ID: mdl-26497802

ABSTRACT

BACKGROUND: Accurate and meaningful dose metrics are a basic requirement for in vitro screening to assess potential health risks of engineered nanomaterials (ENMs). Correctly and consistently quantifying what cells "see," during an in vitro exposure requires standardized preparation of stable ENM suspensions, accurate characterizatoin of agglomerate sizes and effective densities, and predictive modeling of mass transport. Earlier transport models provided a marked improvement over administered concentration or total mass, but included assumptions that could produce sizable inaccuracies, most notably that all particles at the bottom of the well are adsorbed or taken up by cells, which would drive transport downward, resulting in overestimation of deposition. METHODS: Here we present development, validation and results of two robust computational transport models. Both three-dimensional computational fluid dynamics (CFD) and a newly-developed one-dimensional Distorted Grid (DG) model were used to estimate delivered dose metrics for industry-relevant metal oxide ENMs suspended in culture media. Both models allow simultaneous modeling of full size distributions for polydisperse ENM suspensions, and provide deposition metrics as well as concentration metrics over the extent of the well. The DG model also emulates the biokinetics at the particle-cell interface using a Langmuir isotherm, governed by a user-defined dissociation constant, K(D), and allows modeling of ENM dissolution over time. RESULTS: Dose metrics predicted by the two models were in remarkably close agreement. The DG model was also validated by quantitative analysis of flash-frozen, cryosectioned columns of ENM suspensions. Results of simulations based on agglomerate size distributions differed substantially from those obtained using mean sizes. The effect of cellular adsorption on delivered dose was negligible for K(D) values consistent with non-specific binding (> 1 nM), whereas smaller values (≤ 1 nM) typical of specific high-affinity binding resulted in faster and eventual complete deposition of material. CONCLUSIONS: The advanced models presented provide practical and robust tools for obtaining accurate dose metrics and concentration profiles across the well, for high-throughput screening of ENMs. The DG model allows rapid modeling that accommodates polydispersity, dissolution, and adsorption. Result of adsorption studies suggest that a reflective lower boundary condition is appropriate for modeling most in vitro ENM exposures.


Subject(s)
Computer Simulation , Dose-Response Relationship, Drug , Nanostructures
11.
Biol Reprod ; 91(6): 146, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25395673

ABSTRACT

Sma- and Mad-related protein 4 (SMAD4) is the central mediator of the transforming growth factor beta signaling pathway and is closely related to mammalian reproductive ability and the development of ovarian follicles. However, little is currently known about the role of SMAD4 in mammalian follicular granulosa cell (GC) apoptosis or its regulation by miRNAs. Here, we found that the porcine SMAD4 protein was expressed at high levels in GCs and oocytes from primary, preantral, and antral follicles, and only slightly expressed in theca cells; its expression level was down-regulated in apoptotic ovarian GCs, suggesting that SMAD4 may be involved in ovary development and selection. Overexpression and knockdown of SMAD4 increased the proliferation and apoptosis of cultured porcine GCs, respectively. In addition, the use of miRNA mimics and luciferase reporter assays revealed that miRNA-26b (miR-26b) functions as a proapoptotic factor in porcine follicular GCs by targeting the 3'-untranslated region of the SMAD4 gene. Overexpression of miR-26b in follicular GCs suppressed SMAD4 mRNA and protein levels, resulting in down-regulation of the antiapoptotic BCL-2 gene and the promotion of GC apoptosis. Furthermore, transforming growth factor beta 1 (TGF-beta1) down-regulates miR-26b expression in porcine GCs. Taken together, these data suggest that SMAD4 plays a critical role in porcine follicular GC apoptosis and follicular atresia and that miR-26b may have a proapoptotic role in GCs by regulating the expression of SMAD4 in the transforming growth factor beta signaling pathway.


Subject(s)
Apoptosis/genetics , Granulosa Cells/metabolism , MicroRNAs/physiology , Smad4 Protein/genetics , Swine/genetics , Animals , Cells, Cultured , Female , Follicular Phase/genetics , Follicular Phase/metabolism , Gene Expression Regulation , Ovarian Follicle/metabolism , Ovary/metabolism , Smad4 Protein/metabolism
12.
Food Chem Toxicol ; 192: 114934, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39151877

ABSTRACT

Quercetin has been shown to mitigate the cytotoxic effects of heavy metals. While copper is an essential trace element for bodily functions, excessive intake has been linked to impaired female reproductive function. Transcriptome analysis was employed to identify genes that are differentially expressed in response to high copper and were validated through qRT-PCR and western blotting. ATP content and Tunel were used to identify the damage of mitochondrial and cell apoptosis. PPI analysis revealed that MKI67, TOPII, ASPM, CASP3, PLK1, and TTK are central proteins within the network. Additionally, exposure to elevated levels of copper resulted in the dysregulation of 86 genes associated with mitochondria. Conversely, treatment with quercetin (QUE) in combination with high copper led to the normalization of 42 mitochondria-related genes previously affected by high copper levels. Furthermore, CuSO4 decreases ATP content and induces cell apoptosis, which can be reversed by QUE. Results suggest that elevated copper levels could lead to oxidative stress and apoptosis by inducing mitochondrial damage, while QUE has the potential to mitigate these effects, ultimately safeguarding granulosa cells and halting the progression of cell death. This study provides novel insights into the molecular pathways involved in female reproductive toxicity caused by excessive copper exposure.

13.
Org Lett ; 26(34): 7144-7148, 2024 Aug 30.
Article in English | MEDLINE | ID: mdl-39158211

ABSTRACT

Dearomative trifunctionalization of quinolinium salts is one of the most straightforward approaches to access biologically relevant multisubstituted tetrahydroquinolines. However, research in this field is still in its infancy. Here, we report a base-controlled regiodivergent dearomative trifunctionalization strategy for transforming quinoliniums into two kinds of structurally intriguing tetrahydroquinoline polycycles through a one-pot three-component cascade annulation. The key is the in situ generation of a "Nu-E-Nu" trifunctional reagent that can precisely identify the matched reactive sites of quinoliniums.

14.
Microbiol Resour Announc ; 13(6): e0010724, 2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38651915

ABSTRACT

Microbes play a significant role in the cleanup of xenobiotic contaminants. Based on metagenomes derived from long-term enrichment cultures grown on xenobiotic solvents, we report 166 metagenome-assembled genomes, of which 137 are predicted to be more than 90% complete. These genomes broaden the representation of xenobiotic degraders.

15.
Drug Des Devel Ther ; 18: 767-780, 2024.
Article in English | MEDLINE | ID: mdl-38495631

ABSTRACT

Purpose: Pulmonary arterial hypertension (PAH) is a devastating disease with little effective treatment. The proliferation of pulmonary artery smooth muscle cells (PASMCs) induced by the nuclear factor-κB (NF-κB) signaling activation plays a pivotal role in the pathogenesis of PAH. Forsythoside B (FTS•B) possesses inhibitory effect on NF-κB signaling pathway. The present study aims to explore the effects and mechanisms of FTS•B in PAH. Methods: Sprague-Dawley rats received monocrotaline (MCT) intraperitoneal injection to establish PAH model, and FTS•B was co-treated after MCT injection. Right ventricular hypertrophy and pulmonary artery pressure were measured by echocardiography and right heart catheterization, respectively. Histological alterations were detected by H&E staining and immunohistochemistry. FTS•B's role in PASMC proliferation and migration were evaluated by CCK-8 and wound healing assay. To investigate the underlying mechanisms, Western blotting, immunofluorescence staining and ELISA were conducted. The NF-κB activator PMA was used to investigate the role of NF-κB in FTS•B's protective effects against PAH. Results: FTS•B markedly alleviated MCT-induced vascular remodeling and pulmonary artery pressure, and improved right ventricular hypertrophy and survival. FTS•B also reversed PDGF-BB-induced PASMC proliferation and migration, decreased PCNA and CyclinD1 expression in vitro. The elevated levels of IL-1ß and IL-6 caused by MCT were decreased by FTS•B. Mechanistically, MCT-triggered phosphorylation of p65, IκBα, IKKα and IKKß was blunted by FTS•B. FTS•B also reversed MCT-induced nuclear translocation of p65. However, all these protective effects were blocked by PMA-mediated NF-κB activation. Conclusion: FTS•B effectively attenuates PAH by suppressing the NF-κB signaling pathway to attenuate vascular remodeling. FTS•B might be a promising drug candidate with clinical translational potential for the treatment of PAH.


Subject(s)
Caffeic Acids , Glucosides , Hypertension, Pulmonary , Pulmonary Arterial Hypertension , Rats , Animals , NF-kappa B/metabolism , Monocrotaline/adverse effects , Rats, Sprague-Dawley , Vascular Remodeling , Hypertrophy, Right Ventricular/metabolism , Hypertrophy, Right Ventricular/pathology , Hypertension, Pulmonary/chemically induced , Hypertension, Pulmonary/drug therapy , Signal Transduction
16.
Animals (Basel) ; 13(17)2023 Aug 29.
Article in English | MEDLINE | ID: mdl-37685009

ABSTRACT

CuSO4 is the most commonly used feed additive in pig production at present, but long-term ingestion of excessive copper would lead to chronic copper toxicity. High copper could reduce the reproductive efficiency of sows and seriously affect the development of the pig industry. Quercetin (QUE), a powerful antioxidant, reduces toxicity of a number of heavy metals. Porcine granulosa cells (pGCs) are crucial to the fate of follicle development. The present study found that high concentrations of CuSO4 induced ROS production, which resulted in decreased mRNA expression of antioxidant-related genes GPX4, CAT, and SOD2 and increased mRNA expression of SOD1, TRX, and HO-1. The protein expression of antioxidant enzymes SOD2 and HO-1 decreased. Moreover, the concentration of MDA increased, the activity of CAT decreased, and the content of GSH decreased. After high copper treatment, the mitochondrial membrane potential (MMP) was decreased and the morphological structure was changed. However, the combined treatment with Quercetin (QUE) reversed these changes, and the level of cellular oxidative stress decreased. Therefore, we conclude that high copper has oxidative toxicity to pGCs, and QUE could remove the ROS induced by high copper, protect mitochondria from oxidative stress damage, and improve the function of pGCs.

17.
Materials (Basel) ; 16(14)2023 Jul 13.
Article in English | MEDLINE | ID: mdl-37512263

ABSTRACT

The ultra-fast laser heating process of nano-films is characterized by an ultra-short duration and ultra-small space size, in which the classical Fourier law based on the hypothesis of local equilibrium is no longer applicable. Based on the Cattaneo-Vernotte (CV) model and the dual-phase-lag (DPL) model, the two-dimensional analytical solutions of heat conduction in nano-films under ultra-fast laser are obtained using the integral transformation method. The results show that there is a thermal wave phenomenon inside the film, which becomes increasingly evident as the elapse of the lag time of the temperature gradient. Moreover, the wave amplitude in the vertical direction is much larger than that in the horizontal direction of the nano-film. By comparing the numerical result of the two models, it is found that the temperature distribution inside the nano-film based on the DPL model is gentler than that of the CV model. Additionally, the temperature distribution in the two-dimensional solution is lower than that in the one-dimensional solution under the same Knudsen number. In the comparison results of the CV model, the maximum peak difference in the thermal wave reaches 75.08 K when the Knudsen number is 1.0. This demonstrates that the horizontal energy carried by the laser source significantly impacts the temperature distribution within the film.

18.
Phys Rev Lett ; 108(17): 170403, 2012 Apr 27.
Article in English | MEDLINE | ID: mdl-22680842

ABSTRACT

A fundamental difficulty in demonstrating quantum state tomography is that the required resources grow exponentially with the system size. For pure states and nearly pure states, the task of tomography can be more efficient. We proposed two methods for state reconstruction, by (1) minimizing entropy and (2) maximizing likelihood. The algorithm of compressed sampling is employed to solve the optimization problem. Experiments are demonstrated considering 4-qubit photonic states. The results show that (1) much fewer measurements than the standard tomography are sufficient to obtain high fidelity, and (2) the method of maximizing likelihood is more accurate and noise robust than the original reconstruction method of compressed sampling. Furthermore, the physical meaning of the methods of minimizing entropy and maximizing likelihood is clear.

19.
Environ Sci Pollut Res Int ; 29(28): 43319-43340, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35091940

ABSTRACT

Traffic-related pollutants seriously affect human health, and the commute time to and from school is the time when students are exposed greatest to traffic pollution sources. Field measurements were conducted with hand-held instruments while walking along two selected commuting routes in winter and spring. The measured data were then compared with background monitoring data, and the respiratory deposition dose (RDD) was calculated to assess the exposure risk. Particulate matter intake from 2018 to 2020 was calculated. In winter, the average concentrations of PM2.5 and PM10 were higher in the afternoon than in the morning. The highest concentration was 2.94 times greater than the background value. The low-concentration distribution area of the low-traffic route that is off the main road (route B) was more significant than that of the high-traffic route that is near the main road (route A). Moreover, the RDD of route B was consistently lower than that of route A, while the average annual amount of PM2.5 inhalation on route B in 3 years was 16.3% lower than that on route A. Overall, route B is more suitable than route A for students to commute on foot. Based on the findings, a walking route located within a community is a good choice.


Subject(s)
Air Pollutants , Air Pollution , Air Pollutants/analysis , Air Pollution/analysis , Environmental Exposure/analysis , Environmental Monitoring , Humans , Particulate Matter/analysis , Schools , Transportation , Vehicle Emissions/analysis
20.
Article in English | MEDLINE | ID: mdl-36612933

ABSTRACT

While personal protective equipment (PPE) protects healthcare workers from viruses, it also increases the risk of heat stress. In this study, the effects of environmental heat stress, the insulation of the PPE inner-garment layer, and the personal cooling strategy on the physiological and perceptual responses of PPE-clad young college students were evaluated. Three levels of wet bulb globe temperatures (WBGT = 15 °C, 28 °C, and 32 °C) and two types of inner garments (0.37 clo and 0.75 clo) were chosen for this study. In an uncompensable heat stress environment (WBGT = 32 °C), the effects of two commercially available personal cooling systems, including a ventilation cooling system (VCS) and an ice pack cooling system (ICS) on the heat strain mitigation of PPE-clad participants were also assessed. At WBGT = 15 °C with 0.75 clo inner garments, mean skin temperatures were stabilized at 31.2 °C, Hskin was 60-65%, and HR was about 75.5 bpm, indicating that the working scenario was on the cooler side. At WBGT = 28 °C, Tskin plateaued at approximately 34.7 °C, and the participants reported "hot" thermal sensations. The insulation reduction in inner garments from 0.75 clo to 0.37 clo did not significantly improve the physiological thermal comfort of the participants. At WBGT = 32 °C, Tskin was maintained at 35.2-35.7 °C, Hskin was nearly 90% RH, Tcore exceeded 37.1 °C, and the mean HR was 91.9 bpm. These conditions indicated that such a working scenario was uncompensable, and personal cooling to mitigate heat stress was required. Relative to that in NCS (no cooling), the mean skin temperatures in ICS and VCS were reduced by 0.61 °C and 0.22 °C, respectively, and the heart rates were decreased by 10.7 and 8.5 bpm, respectively. Perceptual responses in ICS and VCS improved significantly throughout the entire field trials, with VCS outperforming ICS in the individual cooling effect.


Subject(s)
Body Temperature Regulation , Heat Stress Disorders , Humans , Protective Clothing , Cold Temperature , Temperature , Skin Temperature , Heat Stress Disorders/prevention & control , Hot Temperature
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