We study propagation direction of the traveling wave for the diffusive Lotka–Volterra competition system with bistable nonlinearity in a periodic habitat. By directly proving the strong stability of ...two semitrivial equilibria, we establish a new and sharper result on the existence of traveling wave. Using the method of upper and lower solutions, we provide two comparison theorems concerning the direction of traveling wave propagation. Several explicit sufficient conditions on the determination of the speed sign are established. In addition, an interval estimation of the bistable-wave speed reveals the relations among the bistable speed and the spreading speeds of two monostable subsystems. Biologically, our idea and insight provide an effective approach to find or control the direction of wave propagation for a system in heterogeneous environments.
Legumain is one of the cysteine proteases which can serve as an essential indicator for cancer diagnosis. Near-infrared (NIR) nanoprobes with fluorescence “Turn On” property are advantageous in ...cancer diagnosis. However, to the best of our knowledge, using a completely organic NIR nanoprobe to image legumain activity either in vitro or in vivo has not been reported. Herein, employing a CBT-Cys click condensation reaction, we used a rationally designed NIR probe Cys(StBu)-Ala-Ala-Asn-Lys(Cy5.5)-CBT (1) to synthesize its nanoprobes 1-NPs with self-quenched fluorescence. Cell and animal experiments indicated that our nanoprobes were able to specifically image legumain activity in living cells and tumors with a NIR fluorescence “Turn On” manner. We envision that the nanoprobes could be applied for the diagnosis of legumain-related diseases in the near future.
In this paper, the speed sign of the traveling wave to the bistable Lotka–Volterra competitive lattice system is investigated via the upper–lower solution method as well as the comparison principle. ...We provide an interval estimation for the bistable speed firstly. Two comparison principles are further established to obtain new conditions to the determinacy of the sign of the bistable speed. To our knowledge, this is the first investigation to the lattice system for the propagation direction.
The widespread existence of antibiotics has caused inevitable influence on ecology and humans. In this study, we screened the most commonly used antibiotics, and 64 antibiotics were detected in ...Shanghai, an international metropolis. Most of the target substances were detected in all 46 water samples including main rivers and districts in Shanghai, with concentrations ranging from 0.02 to 502.43 ng L
−1
. In particular, sulfadiazine (502.43 ng L
−1
) had the highest maximum concentration. Besides, risk quotients based on fish suggested that sulfonamides had a medium risk (0.12) in Shanghai. Correlation studies had shown that most compounds with frequencies exceeding 60% were significantly positively correlated with the total concentration. Based on further analysis, sulfadiazine, sulfamerazine, and sulfapyridine were screened as indicators to reflect the pollution status of antibiotics in Shanghai for a long time. The screening conditions for these indicators include detection rate (> 60%), maximum concentration (> 100 ng L
−1
), RQ (> 0.01), and correlation (> 0). In addition, population density may be the main factor for antibiotic pollution through regional comparison. In a word, this work can systematically reflect the overall situation of Shanghai antibiotics and provide support for global data comparison in the future. Meanwhile, we provided the potential indicators that can be applied in the long term and economical monitoring of antibiotics.
The occurrence of anticancer drugs in the environment has attracted wide attention due to its potential environmental risks. The aim of this study was to investigate degradation characteristics and ...mechanism of anticancer drug capecitabine (CPC) by electron beam (EB) irradiation. The results showed that EB was an efficient water treatment process for CPC. The degradation followed pseudo-first-order kinetics with dose constants ranged from 1.27 to 3.94 kGy
−1
. Removal efficiencies in natural water filtered or unfiltered were lower than pure water due to the effect of water matrix components. The degradation was restrained by the presence of NO
2
−
, NO
3
−
and CO
3
2−
, and fulvic acid due to competition of reactive radical •OH. It demonstrated that oxidizing radical played important role in irradiation process. The appropriate addition of H
2
O
2
and K
2
S
2
O
8
providing with oxidizing agents •OH and •SO
4
−
was favorable to improve degradation efficiency of CPC. The possible transformation pathways of CPC including cleavage of the ribofuranose sugar and defluorination were proposed based on intermediate products and were consistent with the theoretical calculation of charge and electron density distribution. Toxicity of CPC and intermediate products were estimated by ECOSAR program. It was found that CPC was transformed to low toxicity products with EB.
A highly sensitive fluorometric method is described for the determination of microRNA-141. It is based on the use of arched probe-mediated isothermal exponential amplification reaction (EXPAR) and of ...DNA-templated silver nanoclusters (DNA-AgNCs). The EXPAR utilizes microRNA-141 as the trigger, polymerases and endonucleases as amplification activators, and two arched probes as exponential amplification templates. This enables the conversion of microRNA to a large number of reporter sequences under isothermal conditions within minutes. The generated reporter sequences act as scaffolds for the synthesis of fluorescent DNA-AgNCs by reduction of Ag (I) with NaBH
4
. The DNA-AgNCs function as signalling fluorophores with excitation/emission maxima at 540/610 nm. The method exhibits high sensitivity for microRNA-141 with a detection limit as low as 0.87 fM and a dynamic range from 1 fM to 500 fM. The method can distinguish nucleotides in the microRNA-200 family.
Graphical abstract
Schematic representation of a fluorometric method for sensitive detection of microRNA based on arched probe-mediated isothermal exponential amplification combined with DNA-templated silver nanoclusters.
The endocrine-disrupting activities of UV filters and synthetic progestin have raised concerns about their adverse risks. In this study, 208 urine samples were collected from Shanghai residents for ...the determination of seven benzophenones (BPs) and six synthetic progestins. The highest median concentration (6.21ng g
−1
Cr) was observed in young adults (21–50 years), followed by a concentration of 3.86 ng g
−1
Cr in elderly adults (over 50 years old), and the lowest median concentration (1.32 ng g
−1
Cr) was found in children (8–11 years old). The detection rates of BP-3 and EE2 in adults were 97% and 82%, and in children were 31% and 24%, respectively. Synthetic progestin levels in Shanghai, China, were relatively low compared to other countries. And the urinary BPs level showed an increasing trend in Chinese in the past 5 years. The principal component analysis suggested that adults’ exposure to BP-1 and BP-3 was related, which occurs through food or dermal absorption of these chemicals present in cosmetic products and coatings. And diet was an important exposure pathway for children exposed to BPs. Despite relatively high levels of synthetic progestin for female and obese, the total estimated daily intake (EDI) was still lower than acceptable daily intake adopted by America. In the Monte-Carlo analysis, the 95th percentile of hazard quotients (HQs) was 0.83, which indicated that potential health risks were appreciated in the studied population.
Abstract Background Pulmonary arteriovenous fistula (PAVF) is a rare disease, and its symptoms lack specificity. For patients with coronary heart disease(CHD), hypertension and other common ...cardiovascular diseases, PAVF is easy to be ignored. We presented a case of massive PAVF complicated with coronary atherosclerotic heart disease by interventional treatment to improve the understanding of this complex disease. Case presentation A 77-year-old female patient was admitted to the hospital due to chest tightness and shortness of breath following activities, which was diagnosed with CHD and hypoxemia in other hospitals. Coronary angiography showed that the patient had severe stenosis of coronary artery while pulmonary vascular DSA showing the patient had PAVF. After interventional therapy of both coronary artery and PAVF, the patient's symptoms were significantly improved. Conclusion We presented a case of massive PAVF complicated with CHD by interventional treatment. For patients with unexplained hypoxemia and symptoms similar with CHD, the possibility of PAVF often leads to oversight, and various auxiliary examinations should be improved to avoid missed diagnosis. And intervention treatment should be carried out to improve the prognosis of patients as much as possible.
Endoplasmic reticulum (ER) stress has been shown to play a critical role in the pathogenesis of hypertension. However, the underlying mechanisms for lowering blood pressure (BP) by suppressing ER ...stress remain unclear. Here, we hypothesized that inhibition of ER stress could restore the balance between RAS components and lower BP in spontaneously hypertensive rats (SHRs).
Wistar-Kyoto (WKY) rats and SHRs received vehicle or 4-PBA, an ER stress inhibitor, in the drinking water for 4 weeks. BP was measured by tail-cuff plethysmography, and the expression of RAS components was examined by Western blot.
Compared with vehicle-treated WKY rats, vehicle-treated SHRs exhibited higher blood pressure and increased renal ER stress and oxidative stress, accompanied by impaired diuresis and natriuresis. Moreover, SHRs had higher ACE and AT
1
R and lower AT
2
R, ACE2, and MasR expressions in the kidney. Interestingly, 4-PBA treatment improved impaired diuresis and natriuresis and lowered blood pressure in SHRs, accompanied by reducing ACE and AT
1
R protein expression and increasing AT
2
R, ACE2, and MasR expression in the kidneys of SHRs. In addition, these changes were associated with the reduction of ER stress and oxidative stress.
These results suggest that the imbalance of renal RAS components was associated with increased ER stress in SHRs. Inhibition of ER stress with 4-PBA reversed the imbalance of renal RAS components and restored the impaired diuresis and natriuresis, which, at least in part, explains the blood pressure-lowering effects of 4-PBA in hypertension.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Acute myocardial infarction (MI) is one of the leading causes of death in humans. Our previous studies showed that gastrin alleviated acute myocardial ischaemia–reperfusion injury. We ...hypothesize that gastrin might protect against heart injury after MI by promoting angiogenesis. An MI model was simulated by ligating the anterior descending coronary artery in adult male C57BL/6J mice. Gastrin was administered twice daily by intraperitoneal injection for 2 weeks after MI. We found that gastrin reduced mortality, improved myocardial function with reduced infarct size and promoted angiogenesis. Gastrin increased HIF-1α and VEGF expression. Downregulation of HIF-1α expression by siRNA reduced the proliferation, migration and tube formation of human umbilical vein endothelial cells. These results indicate that gastrin restores cardiac function after MI by promoting angiogenesis via the HIF-1α/VEGF pathway.
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