A fuel cell is widely considered as recycled clean energy in the application of aerospace. For the reason that the dynamic performance is poor, supercapacitor (SC) or battery is chosen as the ...auxiliary power supply. In this study, the fuel cell and SC power the load in parallel to stable the bus voltage. The flexible control strategy is proposed to optimise the energy allocation between the fuel cell and SC. A simulation model including the refined model of the fuel cell and SC is established to prove.
Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone; PLB), a naturally occurring naphthoquinone isolated from the roots of Plumbaginaceae plants, has been reported to possess anticancer activities in ...both in vitro and in vivo studies, but the effect of PLB on tongue squamous cell carcinoma (TSCC) is not fully understood. This study aimed to investigate the effects of PLB on cell cycle distribution, apoptosis, and autophagy, and the underlying mechanisms in the human TSCC cell line SCC25. The results have revealed that PLB exerted potent inducing effects on cell cycle arrest, apoptosis, and autophagy in SCC25 cells. PLB arrested SCC25 cells at the G2/M phase in a concentration- and time-dependent manner with a decrease in the expression level of cell division cycle protein 2 homolog (Cdc2) and cyclin B1 and increase in the expression level of p21 Waf1/Cip1, p27 Kip1, and p53 in SCC25 cells. PLB markedly induced apoptosis and autophagy in SCC25 cells. PLB decreased the expression of the anti-apoptotic proteins B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xl) while increasing the expression level of the pro-apoptotic protein Bcl-2-associated X protein (Bax) in SCC25 cells. Furthermore, PLB inhibited phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), glycogen synthase kinase 3β (GSK3β), and p38 mitogen-activated protein kinase (p38 MAPK) pathways as indicated by the alteration in the ratio of phosphorylation level over total protein expression level, contributing to the autophagy inducing effect. In addition, we found that wortmannin (a PI3K inhibitor) and SB202190 (a selective inhibitor of p38 MAPK) strikingly enhanced PLB-induced autophagy in SCC25 cells, suggesting the involvement of PI3K- and p38 MAPK-mediated signaling pathways. Moreover, PLB induced intracellular reactive oxygen species (ROS) generation and this effect was attenuated by l-glutathione (GSH) and n-acetyl-l-cysteine (NAC). Taken together, these results indicate that PLB promotes cellular apoptosis and autophagy in TSCC cells involving p38 MAPK- and PI3K/Akt/mTOR-mediated pathways with contribution from the GSK3β and ROS-mediated pathways.
Plumbagin (PLB) has been shown to have anticancer activities in animal models, but the role of PLB in prostate cancer treatment is unclear. This study aimed to investigate the effects of PLB on ...apoptosis and autophagy and the underlying mechanisms in human prostate cancer cell lines PC-3 and DU145. Our study has shown that PLB had potent pro-apoptotic and pro-autophagic effects on PC-3 and DU145 cells. PLB induced mitochondria-mediated apoptosis and autophagy in concentration- and time-dependent manners in both PC-3 and DU145 cells. PLB induced inhibition of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) and p38 mitogen-activated protein kinase (MAPK) pathways and activation of 5'-AMP-dependent kinase (AMPK) as indicated by their altered phosphorylation, contributing to the pro-autophagic activity of PLB. Modulation of autophagy altered basal and PLB-induced apoptosis in both cell lines. Furthermore, PLB downregulated sirtuin 1 (Sirt1), and inhibition of Sirt1 enhanced autophagy, whereas the induction of Sirt1 abolished PLB-induced autophagy in PC-3 and DU145 cells. In addition, PLB downregulated pre-B cell colony-enhancing factor/visfatin, and the inhibition of pre-B cell colony-enhancing factor/visfatin significantly enhanced basal and PLB-induced apoptosis and autophagy in both cell lines. Moreover, reduction of intracellular reactive oxygen species (ROS) level attenuated the apoptosis- and autophagy-inducing effects of PLB on both PC-3 and DU145 cells. These findings indicate that PLB promotes apoptosis and autophagy in prostate cancer cells via Sirt1- and PI3K/Akt/mTOR-mediated pathways with contribution from AMPK-, p38 MAPK-, visfatin-, and ROS-associated pathways.
The treatment of infections caused by bacteria resistant to the vast majority of antibiotics is a challenge worldwide. To evaluate the effect of S-thanatin (an analog of thanatin, a cationic ...antimicrobial peptide isolated from the hemipteran insect Podisus maculiventris) against microbial resistant to antibiotics, we studied its bactericidal kinetics, synergistic effect, resistance, and activity on clinical isolates of Klebsiella pneumoniae resistant to conventional antibiotics with different structures. The bactericidal rate of S-thanatin was more than 99% against K. pneumoniae ATCC 700603 when bacterial cultures were monitored for 60 min. The peptide was synergistic with β-lactam cefepime in most of the clinical MDR isolates tested (7/8). An average value of FIC was 0.3708. No synergy was found between the peptide and amoxicillin, gentamycin, tetracycline, or ciprofloxacin in all bacteria tested. A total of 48 isolates of K. pneumoniae with different resistance spectrum tested was susceptible to S-thanatin. The MICs were 6.25-25 μg/ml. No significant difference in the MICs of S-thanatin between the sensitive isolates and the resistant isolates to single antibiotic was observed (P > 0.05). The resistance of K. pneumoniae ATCC 700603 to S-thanatin was slightly higher, when cultured at sub-inhibitory concentration for 5 days. S-thanatin may be an attractive candidate for developing into an antimicrobial agent.
The expression of the long non-coding RNA (lncRNA) H19 is associated with proliferation in tumors. In order to investigate whether H19 may additionally mediate the proliferation of fibroblasts in ...human keloid disease, the present study collected samples from 24 subjects, including 8 with keloids, 8 with normal scars and 8 normal skin controls. Reverse transcription-polymerase chain reaction revealed that H19 levels were markedly increased in human keloids compared with normal scars and normal skin controls (P=0.017). In order to identify a potential role for H19 in the proliferative activity of human keloid fibroblasts, small interfering (si)RNA-mediated silencing experiments were performed. H19 siRNA treatment markedly inhibited the proliferation of keloid fibroblasts, as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (P=0.008). In order to identify the signaling mediators that are regulated by H19 in keloid fibroblasts, the expression levels of mammalian target of rapamycin (mTOR) and vascular endothelial growth factor (VEGF) were examined using western blotting. The results confirmed that knockdown of H19 inhibited mTOR and VEGF expression. In summary, the results indicate that H19 may be associated with increased proliferative activity of keloid fibroblasts, which may be mediated by mTOR and VEGF.
An ethnicity- and gender-specific normal reference database is necessary for the clinical dual-energy X-ray absorptiometry (DXA) assessment of skeletal status in Chinese children. We used a Lunar ...Prodigy DXA densitometer to measure bone mineral density (BMD), bone mineral content (BMC), and bone area (BA) at total body and subcranial skeleton for 877 healthy Chinese children (505 boys, 372 girls) aged 5-13 yr. The height-for-age, BA-for-height, and BMC-for-BA percentile curves were developed using the LMS method (L, power in Box-Cox transformation; M, median; S, coefficient of variation). We found that total body BMD and subcranial skeleton BMD were highly correlated (r=0.701-0.949), and that total body BMD was significantly higher than subcranial skeleton BMD for each gender and age group (p<0.001). No gender differences in total body and subcranial skeleton BMD were found. Total body lean mass correlated highly with total body BMC and subcranial skeleton BMD and BMC (boys: r=0.888-0.953, girls: r=0.917-0.967) and moderately with total body BMD (boys: r=0.684, girls: r=0.777). The head region accounted for 16-52% and 16-49% of the total body BMC in boys and girls, respectively, and the percentages were negatively correlated with age (boys: r=-0.824, girls: r=-0.864) and height (boys: r=-0.911, girls: r=-0.922). Regression analyses showed that age explained more variance in subcranial skeleton BMD (boys: R(2)=0.641, girls: R(2)=0.685) than in total body BMD (boys: R(2)=0.387, girls: R(2)=0.472). In summary, we have presented an ethnicity- and gender-specific densitometric normal reference database for Chinese children aged 5-13 yr. It should allow for an appropriate clinical assessment of total body bone density in Chinese children as measured by the Lunar Prodigy DXA densitometer.
The aim of this study was to assess the contralateral femoral bone mineral density (BMD) difference as measured by dual-energy X-ray absorptiometry (DXA) in mainland Chinese women and men. We ...measured bilateral proximal femora (i.e., total hip, femoral neck, upper femoral neck, and trochanter) using DXA in 1101 subjects (284 males, 817 females), among whom 504 were postmenopausal. Data were analyzed by descriptive statistics, Student's t-tests, and Pearson's correlation coefficients (r). With bilateral femur measurements and the acquisition of the mean BMD, precision error could be significantly reduced at the total hip, the femoral neck, and the upper femoral neck. Contralateral femoral BMD was highly correlated at all measuring sites (r=0.879-0.964). For the male group and for the postmenopausal subgroup, no significant differences in contralateral femoral BMDs were found. In the postmenopausal women, the percentage of subjects with discordance in classification (i.e., normal, osteopenia, and osteoporosis) for the left and right femora declined from 16.9% to 8.1% with precision adjustment. From a population perspective, since there may still be a considerable number of misdiagnosed cases, we therefore suggest that bilateral femur measurements may be justified for postmenopausal Chinese women.
Abstract Hand bone mineral density (BMD) in adults was found to be significantly correlated with various skeletal sites, including the total body. However, the relationships between hand and total ...body bone measurements have yet to be explored for children. We conducted a cross-sectional study of 892 normal Chinese children (511 males, 381 females) aged 5–14 years by measuring the BMD and bone mineral content (BMC) at the total hand, upper limb, subtotal body, and total body using dual-energy X-ray absorptiometry (DXA). We found that hand BMD and BMC increased with age for both genders. Female children had significantly higher hand BMD and BMC than males. Age explained more variance in hand BMD for females ( R2 = 0.727) than for males ( R2 = 0.596). For both genders, hand BMD and BMC correlated highly with age, weight, height, total body lean mass, and BMD and BMC at the upper limb, subtotal body, and total body ( r = 0.730–0.965, p < 0.001) and moderately with body mass index and total body fat mass ( r = 0.525–0.701, p < 0.001). Therefore, the hand DXA scan can potentially be a new tool for the clinical assessment of bone health in children.
This study was aimed at determining the correlation between regional body composition and total body fat percentage (TBF%), as measured by dual-energy X-ray absorptiometry (DXA), among Chinese women ...and men. Men (n=203) and women (n=630), aged 20-87yr, were assessed for height, weight, and body mass index (BMI) and for total body, lumbar spine (L2-L4), and left and right proximal femur fat percentage using DXA. Based on their BMI, male and female subjects were subdivided into 4 groups. For all groups, the TBF% derived from the total body scan was strongly correlated with spine %fat (r range: 0.60-0.96) and the left and right femur %fat (r range: 0.72-0.80 and 0.69-0.83, respectively), as obtained from regional scans. In stepwise regression, TBF% was best assessed by spine %fat, left femur %fat, age, and BMI for both genders (male: R(2)=0.88; female: R(2)=0.84). Equations with spine %fat, age, and BMI also provided good estimates of TBF% (male: R(2)=0.80; female: R(2)=0.75), whereas android and gynoid %fat were predicted with spine %fat and left femur %fat, respectively, and the predicted fat percentage ratio of android to gynoid (A/G) could be obtained from spine %fat and left femur %fat. The cross-validation results showed that the accuracy of all prediction equations was high in the male group, whereas prediction equations with high-to-moderate accuracy were found in the female group. Therefore, for DXA systems that do not offer total body scan, clinicians can assess TBF% using data obtained from regional scans.
This study was aimed at assessing the correlations between the bone mineral density (BMD) of the hand and other skeletal sites in Chinese women and men. We measured the BMD of the total body, the ...anteroposterior lumbar spine (L2-L4), bilateral proximal femurs (i.e., total hip, femoral neck, and trochanter), and bilateral total hands in 363 Chinese adults (96 males, 267 females) using dual-energy X-ray absorptiometry (DXA). Data were analyzed by descriptive statistics, Student's t tests, and Pearson's correlation coefficients (r). We found that bilateral hand measurements reduced precision error by 36% as compared with a single hand measurement. Dominant hand BMD was significantly higher than nondominant hand BMD. For both the dominant and nondominant sides, hand BMD was significantly higher in males than in females. Hand BMD correlated significantly (p<0.001) with the BMD of all skeletal sites for all subjects (r=0.681-0.848), the male group (r=0.568-0.857), and the female group (r=0.687-0.859). After normal references for the Chinese population have been established, further investigations may determine the clinical usefulness of hand BMD measurement in the diagnosis of osteoporosis and the prediction of fracture risk.
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