The patterns forming during adiabatic gas–liquid flows in single microchannels are reviewed and the parameters influencing pattern transitions are discussed. Six major patterns were identified: the ...surface tension dominated bubbly and Taylor flows, the transitional churn and Taylor–annular flows, and the inertia dominated dispersed and annular flows. From the various parameters that have been studied in the literature, channel size, phase superficial velocities, liquid phase surface tension, wall wettability and inlet conditions were found to affect the flow pattern formed while channel cross sectional geometry affected the patterns but to a lesser degree. Liquid viscosity and flow orientation with respect to gravity also seemed to play some role but the results were not conclusive. A universal flow regime map does not seem to exist and this is attributed to a lack of consistency in the inlets used in the various studies as well as to the effects of wall properties, such as wettability, contamination and roughness which are not usually varied systematically or reported. From the different flow regime maps suggested, those using
U
GS
–
U
LS
as coordinates represented better the transitions between patterns.
The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA) that plays a key role in the malignant phenotype of tumors. Although abnormal regulation of ...lncRNA MALAT1 impacts clinical prognostic and tumor metastasis, its function remains unclear in ovarian cancer.
We collected 64 samples of surgical EOC tissues and 30 samples of normal ovarian tissues at the Department of Gynecology of Harbin Medical University (Harbin, China). The 30 control samples of ovarian surface epithelial tissues were obtained from patients diagnosed with uterine fibroids and scheduled hysterectomy with oophorectomy.
The present study discovered that MALAT1 was upregulated in tumor tissues and ovarian cancer cell lines. Further, the 5-year overall survival was higher in the lower expression of the MALAT1 group. MALAT1 inhibition impeded cell proliferation, invasion and metastasis, and promoted cell apoptosis in both in vivo and in vitro. Furthermore, silencing of MALAT1 hindered the expression of epithelial-to-mesenchymal transition (EMT)-related genes and MMPS. The evidence showed that MALAT1 induce EMT via PI3K/AKT pathway.
Our research suggests that MALAT1 transforms metastasis in EOC and may be a prospective therapeutic target.
With increased global warming, cyanobacteria are blooming more frequently in lakes and reservoirs, severely damaging the health and stability of aquatic ecosystems and threatening drinking water ...safety and human health. There is an urgent demand for the effective prediction and prevention of cyanobacterial blooms. However, it is difficult to effectively reduce the risks and loss caused by cyanobacterial blooms because most methods are unable to successfully predict cyanobacteria blooms. Therefore, in this study, we proposed a new cyanobacterial bloom occurrence prediction method to analyze the probability and driving factors of the blooms for effective prevention and control. Dominant cyanobacterial species with bloom capabilities were initially determined using a dominant species identification model, and the principal driving factors of the dominant species were then analyzed using canonical correspondence analysis (CCA). Cyanobacterial bloom probability was calculated using a newly-developed model, after which, the probable mutation points were identified and thresholds for the principal driving factors of cyanobacterial blooms were predicted. A total of 141 phytoplankton data sets from 90 stations were collected from six large-scale hydrology, water-quality ecology, integrated field surveys in Jinan City, China in 2014–2015 and used for model application and verification. The results showed that there were six dominant cyanobacterial species in the study area, and that the principal driving factors were water temperature, pH, total phosphorus, ammonia nitrogen, chemical oxygen demand, and dissolved oxygen. The cyanobacterial blooms corresponded to a threshold water temperature range, pH, total phosphorus (TP), ammonium nitrogen level, chemical oxygen demand, and dissolved oxygen levels of 19.5–32.5 °C, 7.0–9.38, 0.13–0.22 mg L−1, 0.38–0.63 mg L−1, 10.5–17.5 mg L−1, and 4.97–8.28 mg L−1, respectively. Comparison with research results from other global regions further supported the use of these thresholds, indicating that this method could be used in habitats beyond China. We found that the probability of cyanobacterial bloom was 0.75, a critical point for prevention and control. When this critical point was exceeded, cyanobacteria could proliferate rapidly, increasing the risk of cyanobacterial blooms. Changes in driving factors need to be rapidly controlled, based on these thresholds, to prevent cyanobacterial blooms. Temporal and spatial scales were critical factors potentially affecting the selection of driving factors. This method is versatile and can help determine the risk of cyanobacterial blooms and the thresholds of the principal driving factors. It can effectively predict and help prevent cyanobacterial blooms to reduce the global probability of occurrence, protect the health and stability of water ecosystems, ensure drinking water safety, and protect human health.
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•Our method can analyze probability and driving factors before cyanobacteria bloom occur.•Studies from other regions approved our method and results.•Probability of 0.75 is a critical point for cyanobacteria bloom prevention.•It can effectively predict cyanobacteria blooms and help reduce occurrence risk.
Impedance control is frequency-dependent in the twofold sense: (1) the impedance matching error can only be attenuated arbitrarily small over a low-frequency range due to the water bed effect ...(Freudenberg et al., 2003), and (2) the impedance matching error always diverges to infinity as the frequency tends to infinity since no causal controller can track arbitrarily fast signals. To sum up, we can only shape the robot impedance over some low-frequency range which may be very small due to the limitation resulting from the robot's inherent high-frequency characteristics. Unfortunately, this fact was underestimated in the existing impedance control schemes. In this paper, a frequency-aware linear impedance control synthesis technique is developed for FSAs based on
control theory, which is also suitable for the general robot system in the condition that the robot dynamics is linearised around an equilibrium configuration or compensated with its inverse dynamics model to form an exact-linearised system a priori. With the powerful tool, we study the impedance shaping technique and address the two long-standing issues: (1) Under what conditions, an impedance-controlled FSA can exceed its physical stiffness? (2) Can a stiff FSA render a wider stiffness range than its softer counterparts?
The characteristics of mass transfer from gas to liquid during Taylor flow in capillaries with diameter less than 1
mm with and without chemical reaction were investigated with Computational Fluid ...Dynamics modelling using 5
vol.% CO
2/N
2 mixture and 0.2
M NaOH or water as the gas and liquid phases, respectively. The effects on mass transfer of chemical reaction and of bubble velocity, bubble geometry and capillary size were studied. For the simulations a unit cell was used (a Taylor bubble and a liquid slug) with periodic boundary conditions at the inlet and the outlet of the unit cell, while the CO
2 concentration at the gas–liquid interface was dynamically updated to reflect the decreasing amount of CO
2 in the gas phase. The numerical model was able to predict well experimental data on the chemical absorption of CO
2 in a NaOH solution. The mass transfer performance for the various cases studied was evaluated using the CO
2 absorption fraction
X% (the percentage of CO
2 transferred from the gas to the liquid phase) and the liquid utilization index
Ψ (mole of CO
2 absorbed per unit volume of NaOH). Both these parameters were significantly higher in the case of chemical absorption compared to the physical one. The volumetric mass transfer coefficients,
k
L
a, for the physical absorption were found to vary between 0.3 and 1.5
s
−1 in line with literature values for Taylor flow but higher than in normal gas–liquid contactors while the specific areas achieved varied between 1000 and 10,000
m
2/m
3. Interestingly, for the conditions investigated,
k
L
a was found to increase with channel size as did
X% during physical absorption. The absorption fraction, however, increased with decreasing channel size when reaction was present. When reaction was present, CO
2 absorption was found to be enhanced between 3 and 12 times compared to physical absorption.
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•A framework for integrated water ecosystem health (WEH) assessment was developed.•It provided a comprehensive view of the health status of surface water ecosystems.•It overcame ...narrow perspective of previous one-community and one-index based method.•Ecological restoration and water resource management can be based on this framework.
Healthy river ecosystems can provide fundamental ecological services for human survival and social development. However, previous studies that have sought to assess river ecosystem health have primarily focused on individual biological communities rather than on all aquatic communities and have been based on a single-index assessment method, thereby leading to large uncertainties in the results. In this study, we developed a new framework for the integrated assessment of aquatic ecosystem health based on the principal communities of fish, zoobenthos, phytoplankton, and zooplankton in rivers. An index of biotic integrity was used to evaluate the health of fish and zoobenthos communities, and a diversity index was used to evaluate the health of zooplankton and phytoplankton communities. To integrate the health assessment results from these four communities, a quantile normalization method was developed, where uncertainties in assessments obtained using the diversity index were well compensated for by the assessments obtained using the biotic integrity index. The framework was then applied to a pilot city, which is being constructed as a civilized freshwater ecological city in China. The results were then compared with those previously obtained based on the single-community method. Using this new framework, we found that the aquatic ecosystem health changed regularly in space and over time. Large differences were detected among the assessments of the four individual communities based on the single-community method, with the health score determined using phytoplankton being the highest, followed by that of zoobenthos, zooplankton, and fish, which made it difficult to reach a definitive conclusion regarding aquatic health status. The integrated assessment framework presented in this study successfully overcame the narrow perspective of the single-community method, thereby reducing uncertainties in the assessments based only on a single diversity index, and instead provides a comprehensive view of the status of aquatic ecosystem health. Thus, this integrated framework could assist river managers and stakeholders in developing comprehensive strategies for ecological restoration and water resource management and could become a key research tool for the health assessment and rehabilitation of aquatic ecosystems globally.
Global algal blooms have been severely threatening safety of drinking water and development of socio-economy. Effective prevention and accurate control of algal blooms require a quantitative ...assessment of the influence of human activities and identification of priority areas. However, previous studies on the quantitative assessment of the effects of human activities on algal communities are lacking, severely hindering the effective and precise control of algal blooms. This paper proposes a quantitative assessment model to evaluate the impact intensity of human activities on phytoplankton. Applications showed that the proliferation of phytoplankton were more limited by nutrients such as total phosphorus and ammonia where waters are less influenced by human activities, yet were less limited by these nutrients where there are highly intensive human activities. The density of phytoplankton in waters increased with an increase in human activity intensity, particularly in concentrated agricultural areas, which are priority areas for the prevention and control of algal blooms. The methodologies can clearly identify key areas for algal bloom prevention and control and can provide scientific evidence for water and nutrient management throughout the world, reducing the risk of algal blooms and ensuring aquatic ecosystem health and potable water safety.
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•We presented a methodology for evaluation of human impact on phytoplankton.•Quantitative assessment of human activity impact levels can be achieved.•It can identify priority areas for the prevention and control of algal blooms.
Bromodomain-containing protein 4 (BRD4) is an important epigenetic reader implicated in the pathogenesis of a number of different cancers and other diseases. Brd4-null mouse embryos die shortly after ...implantation and are compromised in their ability to maintain the inner cell mass, which gives rise to embryonic stem cells (ESCs). Here we report that BRD4 regulates expression of the pluripotency factor Nanog in mouse ESCs and preimplantation embryos, as well as in human ESCs and embryonic cancer stem cells. Inhibition of BRD4 function using a chemical inhibitor, small interfering RNAs, or a dominant-negative approach suppresses Nanog expression, and abolishes the self-renewal ability of ESCs. We also find that BRD4 associates with BRG1 (brahma-related gene 1, aka Smarca4 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4)), a key regulator of ESC self-renewal and pluripotency, in the Nanog regulatory regions to regulate Nanog expression. Our study identifies Nanog as a novel BRD4 target gene, providing new insights for the biological function of BRD4 in stem cells and mouse embryos. Knowledge gained from these non-cancerous systems will facilitate future investigations of how Brd4 dysfunction leads to cancers.
The present study introduces a systematic approach to disperse graphene oxide (GO) during emulsion polymerization (EP) of Polyaniline (PANI) to form nanocomposites with improved electrical ...conductivities. PANI/GO samples were fabricated by loading different weight percents (wt%) of GO through modified in situ EP of the aniline monomer. The polymerization process was carried out in the presence of a functionalized protonic acid such as dodecyl benzene sulfonic acid, which acts both as an emulsifier and protonating agent. The microstructure of the PANI/GO nanocomposites was studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV–Vis spectrometry, Fourier transform infrared, differential thermal, and thermogravimetric analyses. The formed nanocomposites exhibited superior morphology and thermal stability. Meanwhile, the electrical conductivities of the nanocomposite pellets pressed at different applied pressures were determined using the four-probe analyzer. It was observed that the addition of GO was an essential component to improving the thermal stability and electrical conductivities of the PANI/GO nanocomposites. The electrical conductivities of the nanocomposites were considerably enhanced as compared to those of the individual PANI samples pressed at the same pressures. An enhanced conductivity of 474 S/m was observed at 5 wt% GO loading and an applied pressure of 6 t. Therefore, PANI/GO composites with desirable properties for various semiconductor applications can be obtained by in situ addition of GO during the polymerization process.
Breweries, as the major users of fossil fuels, are constantly under economic and environmental pressure to minimize energy consumption and residual management costs. Biogas generation from brewing ...wastes is a realistic solution for significantly reducing fossil fuel use. Brewers' spent grain (BSG) forms about eighty per cent of the total wastes from a brewing plant. BSG has a high cellulose and non-cellulosic polysaccharides content which makes it potential for biogas production. This paper reviews the potential applications of BSG as an alternative substrate for production of biogas and the recent achievements which have been attained in anaerobic digestion (AD) technology. The usability of BSG in diverse technologies including production of animal and human food and as a medium for growing microorganisms and enzymes is reviewed. The chemical processes involved in producing biogas from BSG are discussed.
Brewers' spent grain; Anaerobic digestion; Biogas production; Cellulose and non-cellulosic Polysaccharides.
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