Traditional polymeric fibrous membranes have been extensively used to reduce the health risks caused by airborne particulate matter (PM), leading to the dramatically increasing pollution of plastics ...and microplastics. Although great efforts have been made to develop poly(lactic acid) (PLA)-based membrane filters, they are frequently dwarfed by their relatively poor electret properties and electrostatic adsorptive mechanisms. To resolve this dilemma, a bioelectret approach was proposed in this work, strategically involving the bioinspired adhesion of dielectric hydroxyapatite nanowhiskers as a biodegradable electret to promote the polarization properties of PLA microfibrous membranes. In addition to significant improvements in tensile properties, the incorporation of hydroxyapatite bioelectret (HABE) enabled remarkable increase in the removal efficiencies of ultrafine PM
in a high-voltage electrostatic field (10 and 25 kV). This was exemplified by the largely increased filtering performance (69.75%, 23.1 Pa) for PLA membranes loaded with 10 wt% HABE at the normal airflow rate (32 L/min) compared to the pristine PLA counterpart (32.89%, 7.2 Pa). Although the filtration efficiency of PM
for the counterpart dramatically decreased to 21.6% at 85 L/min, the increment was maintained at nearly 196% for the bioelectret PLA, while an ultralow pressure drop (74.5 Pa) and high humidity resistance (RH 80%) were achieved. The unusual property combination were ascribed to the HABE-enabled realization of multiple filtration mechanisms, including the simultaneous enhancement of physical interception and electrostatic adsorption. The significant filtration applications, unattainable with conventional electret membranes, demonstrate the bioelectret PLA as a promising biodegradable platform that allows high filtration properties and humidity resistance.
To alleviate the water-blocking effect in the hydraulic fracturing process and promote coal seam gas extraction, the influence of gas wettability alteration on the water-blocking effect and gas ...desorption was investigated. First, according to the contact angle, infrared spectrum, and surface energy measurement experiments, 3.5% polyacrylamide (PAM) was selected as the gas wettability alteration agent and used to treat the coal samples. After treatment with PAM, the hydroxyl and surface energy of the coal decreased, which altered the gas wettability. Second, the water injection desorption experiment results show that both 4% alkyl polyglucoside (APG) and 3.5% PAM solution can alleviate the water-blocking effect and promote coal gas desorption during water injection. The same experiment was performed by varying the gas pressure. When the gas pressure exceeds 3.25 MPa, APG inhibits gas desorption, indicating that it is unsuitable for alleviating the water-blocking effect. Furthermore, the mechanism by which gas wettability alteration relieves the water-blocking effect was analyzed from macroscopic and microscopic perspectives. Macroscopically, PAM had a high removal rate of the liquid-phase retention effect in coal and can hardly be retained in coal. Microscopically, after gas wettability alteration, the number of hydrophilic functional groups on the surface of coal decreased. The above results in the system changing from hydrophilic to hydrophobic, and correspondingly, the capillary pressure in pores or fractures of coal changes from resistance to a driving force. Therefore, compared with the original coal sample, the water in the coal is more likely to flow back, which alternates the water-blocking effect and promotes gas desorption. This study provided a laboratory prediction method for verifying the effects of gas wettability alteration agents on coal gas extraction.
•The mechanism of wettability alteration was analyzed.•Gas wettability alteration on water blocking effect and desorption were studied.•Influence mechanism of gas wettability alteration on gas desorption of coal.
Accurate acquisition of the coal seam permeability is of great significance to gas drainage. Field measurements are more reliable to determine the coal permeability than laboratory. The Radial Flow ...Permeability (RFP) measurement is the most used field measuring method to measure the coal seam permeability in Chinese coal mines. The theoretical basis of the RFP method is the single-porosity medium flow theory and the gas content in coal seams is described by a parabolic equation. However, coal is a typical dual-porosity medium. The simplifications may lead to nonnegligible influence on the accuracy of the RFP method, which are not well documented in the literature. In this paper, three different mathematical models of gas flow in coal seams are established. The field gas flow data was matched by these three models to prove the reliability of these models. Then the influences of single-porosity simplification and the parabolic gas content simplification on the accuracy of the RFP method were investigated by comparing the differences of gas flow rates and gas pressures. Results show that there are apparent deviations of gas flow rate and gas pressure between these three models. The precision of the RFP method rapidly reduces with the increase of cleat spacing, which is induced by the single-porosity simplification; the precision decreases with the increase of Langmuir volume, first increases and then declines with the increase of Langmuir pressure, which are led by the gas content simplification. Moreover, because of the imperfections of the numerical calculus in the derivation of the RFP method, the calculated value is always smaller than the true value of coal seam permeability.
•The deficiencies of the Radial Flow Permeability method are analyzed.•Three distinct gas flow models based on dual and single porosity theory are proposed.•Critical influencing factors on in-situ permeability measurement are investigated.
Loose-fitting powered air-purifying respirators (LF-PAPRs) are increasingly used in hospitals and coal mines because of their high comfort and protection level, but the utilization faces the ...challenges of 8-hr continuous high protection requirements in the hospital environment and the coupling effects of high temperature, high humidity, high dust concentration in coal mines. Based on the self-developed powered air-purifying respirator simulation test system, this study explores the 8-hr changes of supplied airflow, the relative air pressure inside the inlet covering (ΔP), and total inward leakage (TIL) of four models of LF-PAPRs in simulated hospital and coal mine environments. Results show that:
(1)
In a simulated hospital environment, all four LF-PAPRs showed filter cartridge blockage within 5 ∼ 6 hr of continuous operation; while in the simulated coal mine, three models of LF-PAPRs showed filter cartridge blockage within 3 hr.
(2)
In both the hospital and coal mine environments, there are cases where the supplied airflow of LF-PAPRs dropped below 170 L/min within 3 hr.
(3)
In a simulated hospital environment, the ΔP of all LF-PAPRs maintained positive within 5-6 hr; while in the simulated coal mine, the ΔP of two LF-PAPRs, respectively, appeared negative after 1 hr and 1.6 hr operation. (4) The maximum TIL of the tested LF-PAPRs, respectively ranged from 0.5-0.9% and 1.4-3% in simulated hospital and coal mine environments. (5) In both hospital and coal mine environments, the supplied airflow and ΔP of each LF-PAPR showed a decreasing trend with increasing test duration, while the TIL significantly increased with testing time. (6) The supplied airflow, ΔP, and TIL of each LF-PAPR in the simulated hospital environment performed better than those in the coal mine. This study evaluated the performance of PAPR under the most severe operating conditions, and respirator performance may differ under in-situ conditions.
The objective of this pilot study was to determine the minimum operational flow for loose-fitting powered air-purifying respirators (PAPR) used in healthcare cleaning services. An innovative ...respiratory flow recording device was worn by nine healthcare workers to obtain the minute volume (MV, L/min), mean inhalation flow (MIF, L/min), and peak inhalation flow (PIF, L/min) while performing "isolation unit work" (cleaning and disinfecting) of a patient room within 30 min. The MV and PIF were compared with the theoretical values obtained from an empirical formula. The correlations of MV, MIF, and PIF with subjects' age, weight, height, body surface area (A
Du
), and body mass index (BMI) were analyzed. The average MV, MIF, and PIF were 33, 74, and 107 L/min, with maximal airflow rates of 41, 97, and 145 L/min, respectively, which are all below the current 170 L/min minimum operational flow for NIOSH certified loose-fitting PAPRs.
The antiproliferative effect of cardamonin on mTORC1 is related with downregulation of Raptor. We investigated the mechanism that cardamonin decreases Raptor expression through caspase-mediated ...protein degradation. SKOV3 cells and HeLa cells were pretreated with caspase inhibitor z-VAD-fmk for 30 min and then exposed to different doses of cardamonin and cisplatin, respectively. We analyzed the gene expression of caspases based on TCGA and GTEx gene expression data in serous cystadenocarcinoma and normal tissues, monitored caspase activity by caspase colorimetric assay kit, detected expression of mTORC1-associated proteins and apoptosis-associated proteins by western blotting, and finally detected cell viability by methyl thiazolyl tetrazolium (MTT) assay. A different expression of caspases except caspase-1 was found between serous cystadenocarcinoma and normal tissues. Raptor was cleaved when caspases were activated by cisplatin and caspase-6/caspase-8 was activated by cardamonin in SKOV3 cells. We further used a monoclonal antibody recognizing the N-terminal part of Raptor to find that Raptor was cleaved into a smaller fragment of about 70 kDa by cardamonin and was rescued by z-VAD-fmk treatment. As a result of Raptor cleavage, mTORC1 activity was decreased and cell viability was inhibited, while cell apoptosis was induced in SKOV3 cells. Notably, similar results are only observed in HeLa cells with a high dose of cardamonin. We concluded that caspase-mediated cleavage of Raptor might be an important mechanism in that cardamonin regulated Raptor and mTORC1 activity.
Analyses of extensive, nationally representative databases indicate a rising prevalence of venous thromboembolism (VTE) among critically ill children. However, the majority of studies on childhood ...VTE have primarily concentrated on Caucasian populations in the United States and European countries. There is a lack of epidemiological studies on VTE in Chinese children.
We conducted a retrospective cohort study of data from the Pediatric Intensive Care (PIC) database. Data were obtained and extracted by using Structured Query Language (SQL) and the administrative platform pgAdmin4 for PostgreSQL. Bivariate analyses were conducted in which categorical variables were analyzed by a chi-square test and continuous variables were analyzed by a Student's t-test. Separate multivariable logistic regressions were employed to investigate the associations between VTE and sociodemographic factors as well as clinical factors.
Our study included 12,881 pediatric patients from the PIC database, spanning the years 2010 to 2018. The incidence rate of pediatric VTE was 0.19% (24/12,881). The venous thrombotic locations were deep venous thrombosis extremities (n = 18), superior vena cava (n = 1), cerebral sinovenous (n = 1), and other deep venous thrombosis (n = 4). Univariate analysis showed that age, weight, shock, sepsis, cancer and vasopressor receipt were statistically significant risk factors for pediatric VTE (all p ≤ 0.05). After multivariable logistic regression analysis, only shock (aOR: 6.77, 95%CI: 1.33-34.73, p = 0.019) and admission for sepsis (aOR: 6.09, 95%CI: 1.76-21.09, p = 0.004) were statistically significant associated with pediatric VTE.
In conclusion, data obtained from the Pediatric Intensive Care (PIC) database revealed a prevalence of VTE in pediatric patients of 0.19%. The most common location for venous thrombi was deep venous thrombosis (DVT) in the extremities. We identified that shock and sepsis were statistically significant factors associated with pediatric VTE.
A balance on nutrient supply and redox homeostasis is required for cell survival, and increased antioxidant capacity of cancer cells may lead to chemotherapy failure.
To investigate the mechanism of ...anti-proliferation of cardamonin by inducing oxidative stress in ovarian cancer cells.
After 24 h of drug treatment, CCK8 kit and wound healing test were used to detect cell viability and migration ability, respectively, and the ROS levels were detected by flow cytometry. The differential protein expression after cardamonin administration was analyzed by proteomics, and the protein level was detected by Western blotting.
Cardamonin inhibited the cell growth, which was related to ROS accumulation. Proteomic analysis suggested that MAPK pathway might be involved in cardamonin-induced oxidative stress. Western blotting showed that cardamonin decreased Raptor expression and the activity of mTORC1 and ERK1/2. Same results were observed in Raptor KO cells. Notably, in Raptor KO cells, the effect of cardamonin was weakened.
Raptor mediated the function of cardamonin on cellular redox homeostasis and cell proliferation through mTORC1 and ERK1/2 pathways.
Ovarian cancer is the most fatal tumor characterized by an abundance of tumor-associated macrophage (TAM) infiltrations in women. Functional TAMs, which mainly present M2-like phenotypes and perform ...key functions on tumor progress, have been considered an attractive target for ovarian cancer therapy. Cardamonin showed an excellent antitumor activity in multiple tumor cells. This study aimed to investigate the role of cardamonin on TAMs. With the conditioned medium of ovarian cancer cells, macrophages were induced to TAMs and, accordingly, promoted the proliferation, migration, and invasion of ovarian cancer cells. Cardamonin suppressed alternatively activated (M2) polarization of TAMs and downregulated TAM-secreted tumorigenic factors, thereby hindering the pro-tumor function of TAMs on ovarian cancer cells. Moreover, cardamonin inhibited tumor growth in xenograft nude mice and lowered the expression of CD163 and CD206. Mechanistically, cardamonin inhibited the phosphorylation of mammalian target of rapamycin (mTOR) and signal transducer and activator of transcription 3 (STAT3), resulting in the suppression of M2 polarization. Furthermore, STAT3 is tightly related with mTOR activity. Altogether, these findings implied that cardamonin suppresses the pro-tumor function of TAMs by decreasing M2 polarization via mTOR inhibition, and cardamonin may be a potential therapeutic agent for ovarian cancer.
This study reports that cardamonin, a natural chalcone compound, reduces tumor-associated macrophage M2 polarization and impedes their pro-tumor function via mTOR inhibition, thereby suppressing the proliferation and migration of ovarian cancer cells, which implies that cardamonin may be a potential therapeutic agent for ovarian cancer.
Background mTORC1 (mechanistic target of rapamycin complex 1) is associated with lymphoma progression. Oncogenic RRAGC (Rag guanosine triphosphatase C) mutations identified in patients with ...follicular lymphoma facilitate the interaction between Raptor (regulatory protein associated with mTOR) and Rag GTPase. It promotes the activation of mTORC1 and accelerates lymphomagenesis. Cardamonin inhibits mTORC1 by decreasing the protein level of Raptor. In the present study, we investigated the inhibitory effect and possible mechanism of action of cardamonin in RRAGC-mutant lymphoma. This could provide a precise targeted therapy for lymphoma with RRAGC mutations. Methods Cell viability was measured using a cell counting kit-8 (CCK-8) assay. Protein expression and phosphorylation levels were determined using western blotting. The interactions of mTOR and Raptor with RagC were determined by co-immunoprecipitation. Cells overexpressing RagC wild-type (RagC.sup.WT) and RagC Thr90Asn (RagC.sup.T90N) were generated by lentiviral infection. Raptor knockdown was performed by lentivirus-mediated shRNA transduction. The in vivo anti-tumour effect of cardamonin was assessed in a xenograft model. Results Cardamonin disrupted mTOR complex interactions by decreasing Raptor protein levels. RagC.sup.T90N overexpression via lentiviral infection increased cell proliferation and mTORC1 activation. The viability and tumour growth rate of RagC.sup.T90N-mutant cells were more sensitive to cardamonin treatment than those of normal and RagC.sup.WT cells. Cardamonin also exhibited a stronger inhibitory effect on the phosphorylation of mTOR and p70 S6 kinase 1 in RagC.sup.T90N-mutant cells. Raptor knockdown abolishes the inhibitory effects of cardamonin on mTOR. An in vivo xenograft model demonstrated that the RagC.sup.T90N-mutant showed significantly higher sensitivity to cardamonin treatment. Conclusions Cardamonin exerts selective therapeutic effects on RagC.sup.T90N-mutant cells. Cardamonin can serve as a drug for individualised therapy for follicular lymphoma with RRAGC mutations. Keywords: Raptor, Cardamonin, RagC, mTORC1, Follicular lymphoma
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