The injected fluids in secondary processes supplement the natural energy present in the reservoir to displace oil. The recovery efficiency mainly depends on the mechanism of pressure maintenance. ...However, the injected fluids in tertiary or enhanced oil recovery (EOR) processes interact with the reservoir rock/oil system. Thus, EOR techniques are receiving substantial attention worldwide as the available oil resources are declining. However, some challenges, such as low sweep efficiency, high costs and potential formation damage, still hinder the further application of these EOR technologies. Current studies on nanoparticles are seen as potential solutions to most of the challenges associated with these traditional EOR techniques. This paper provides an overview of the latest studies about the use of nanoparticles to enhance oil recovery and paves the way for researchers who are interested in the integration of these progresses. The first part of this paper addresses studies about the major EOR mechanisms of nanoparticles used in the forms of nanofluids, nanoemulsions and nanocatalysts, including disjoining pressure, viscosity increase of injection fluids, preventing asphaltene precipitation, wettability alteration and interfacial tension reduction. This part is followed by a review of the most important research regarding various novel nano-assisted EOR methods where nanoparticles are used to target various existing thermal, chemical and gas methods. Finally, this review identifies the challenges and opportunities for future study regarding application of nanoparticles in EOR processes.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The landslide susceptibility assessment (LSA) of bedrock and overburden layer slopes subjected to earthquake action remains a challenging issue. In this study, an LSA method was proposed for the ...seismic design of slope engineering. First, a frequency response function was used to identify the vibration characteristics of the slope based on signal processing. The characteristic factors and assessment process of the LSA are then proposed. Based on the similarity principle, the method was applied to three groups of shaking table tests with different overburden thicknesses. The results show that with the increase of the thickness of the overburden layer, the landslide susceptibility of the bedrock and overburden layer slope increases, and the critical amplitude of the seismic landslide continuously decreases. The seismic LSA indexes of the model tests calculated by the proposed method show better robustness than those calculated by the transfer coefficient method. Through linear fitting, the critical amplitude of the seismic landslide was predicted more accurately. A limitation of this method is that multiple acceleration-measuring data points are required for earthquakes and the excitation data must be stable. The feasibility of this method need to be verified for complex multistructured slopes in the future.
•Assessing seismic susceptibility of bedrock and overburden layer slope.•Reliability is verified by three groups of shaking table tests.•Effects of Overburden thickness on the critical amplitude and distance of landslide are analyzed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Owing to its low shear strength, the presence of a weak interlayer frequently plays an adverse role on slope stability. Through a shaking table test, this study investigated the dynamic response of ...the deposit slope with weak interlayer at the exit of the Zheduo Mountain Tunnel reinforced by pile-anchor structures. The acceleration field of the slope, peak value of the dynamic earth pressure of the pile, deformation of the pile, anchor cable tension and load-sharing ratio were considered. The findings demonstrate that as an earthquake intensifies, the slope soil behind a pile gradually becomes compressed; subsequently, tension cracks emerge at the back edge of the slope and expand significantly, eventually forming a penetrating sliding surface. Under various earthquake intensity levels, the acceleration amplification coefficient of the slope increases with the elevation. A weak interlayer can amplify the amplitude of the Fourier spectra, which results in a difference in the vibration between the deposit and bedrock and damage to the slope. When the acceleration exceeds 0.3g, the soil behind pile begins to squeeze it, and the peak value of the dynamic earth pressure first increases and then decreases along the elevation of the pile, reaching its maximum near the sliding surface. The load-sharing ratio of the pile-anchor structure steadily decreases as the peak acceleration of the seismic wave, tension of the anchor cable, and limiting effect of the anchor cable on the pile displacement increase. We suggest that the amplification effect of seismic acceleration should be considered in the seismic design of pile-anchor structures, with local reinforcement near the sliding surface of the pile, and the load-sharing ratio of the structure should be flexible.
•The failure cause of slope with weak interlayer under earthquake is analyzed.•The mechanical mechanism of the pile-anchor structure is systematically revealed.•The failure mode of the above system is proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK, ZAGLJ
To systematically analyze the damage caused by bedrock and overburden layer slope under seismic action, a set of large-scale shaking table test was designed and completed. Interpolation of the ...acceleration amplification coefficient, Hilbert-Huang transform and transfer function was adopted. The damage mechanisms of the bedrock and overburden layer slopes under seismic action are systematically summarized in terms of slope displacement, acceleration field, vibration amplitude, energy, vibration frequency, and damage level. The results show a significant acceleration amplification effect within the slope under seismic action and a localized amplification effect at the top and trailing edges of the slope. With an increase in the input seismic intensity, the difference in the vibration amplitude between the overburden layer and bedrock increased, low-frequency energy of the overburden layer was higher than that of the bedrock, and the vibration frequency of the overburden layer was smaller than that of the bedrock. These differences cause the interface to experience cyclic loading continuously, resulting in the damage degree of the overburden layer at the interface being larger than that of the bedrock, reduction of the shear strength, and eventual formation of landslides. The displacement in the middle of the overburden is always greater than that at the top. Therefore, under the action of an earthquake and gravity, the damage mode of the bedrock and overburden layer slope is such that the leading edge of the critical part pulls and slides at the trailing edge, and multiple tensile cracks are formed on the slope surface.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Pancreatic cancer (PC) remains one of the most lethal human malignancies worldwide. Due to the insidious onset and the rapid progression, most patients with PC are diagnosed at an advanced stage ...rendering them inoperable. Despite the development of multiple promising chemotherapeutic agents as recommended first‐line treatment for PC, the therapeutic efficacy is largely limited by unwanted drug resistance. Recent studies have identified exosomes as essential mediators of intercellular communications during the occurrence of drug resistance. Understanding the underlying molecular mechanisms and complex signaling pathways of exosome‐mediated drug resistance will contribute to the improvement of the design of new oncologic therapy regimens. This review focuses on the intrinsic connections between the chemoresistance of PC cells and exosomes in the tumor microenvironment (TME).
Despite the development of multiple promising chemotherapeutic agents as recommended first‐line treatment for PC, the therapeutic efficacy is largely limited by unwanted drug resistance.Exploring the relation between exosomes and chemoresistance may be conducive to understanding molecular mechanisms and taking effective measures to reduce the development of drug resistance.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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•The average size of AGS reached a balanced distribution after long-term operation.•A suddenly external disturbance influenced the microbial composition of an MBR.•Short time aeration ...changed the characteristics of biomass within the bioreactor.•Larger AGS rapidly reformed after short time aeration.•Filamentous bacteria played an important role in reforming larger AGS.
The investigation aimed at revealing the influence of an external disturbance on the rapid reformation of larger aerobic granular sludge (AGS) in an internal-circulation membrane bioreactor (IC-MBR) after long-term operation. The used IC-MBR was continuously operated well for more than one year, in which, the biomass was still in the state of AGS with a balanced average size at around 200 μm and an even size distribution. By providing short-time aeration to the biomass within this bioreactor, the characteristics of biomass were totally changed in a very short time, including the surface hydrophilicity, physic-chemical properties, and the structure of microbial community, which created suitable conditions for the growth of filamentous bacteria (Saccharibacteria). Such a variation was very beneficial to the reformation of larger AGS, which resulted in the average size of AGS increased to nearly 400 μm with a compact structure and clear edge in no more than one month.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Despite recent advances in multimodal treatments, the prognosis of patients with glioblastoma multiforme (GBM) remains poor. The aim of this study was to evaluate the efficacy of moderately ...hypofractionated simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) combined with temozolomide (TMZ) for the postoperative treatment of GBM.
From February 2012 to February 2018, 80 patients with newly diagnosed and histologically confirmed GBM in our institute were reviewed retrospectively. All patients underwent complete resection or partial resection surgery and then received hypofractionated SIB-IMRT with concomitant TMZ followed by adjuvant TMZ. A total dose of 64 Gy over 27 fractions was delivered to the gross tumor volume (GTV), clinical target volume 1 (CTV1) received 60 Gy over 27 fractions, and CTV2 received 54 Gy over 27 fractions. The progression-free survival (PFS) and overall survival (OS) rates and the toxicities were evaluated. Prognostic factors were analyzed using univariate and multivariate Cox models.
The median follow-up was 16 months (range, 5~72 months). The median PFS was 15 months, and the 1-, 2-, and 3-year PFS rates were 56.0, 27.6, and 19.5%, respectively. The median OS was 21 months, and the 1-, 2-, 3-, and 5-year OS rates were 77.6, 41.6, 32.8, and 13.4%, respectively. The toxicities were mild and acceptable. Age, KPS scores and the total number of TMZ cycles were significant factors influencing patient survival.
Moderately hypofractionated SIB-IMRT combined with TMZ is a feasible and safe treatment option with mild toxicity and good PFS and OS.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
There were no ideal markers to predict the development of radiation pneumonitis (RP). We want to investigate the value of variations of lymphocytes and T lymphocyte subsets in predicting RP after ...radiotherapy (RT) of lung cancer based on previous clinical findings. A total of 182 lung cancer patients who received RT were retrospectively analyzed. Circulating lymphocytes and T lymphocyte subsets were measured before, during, and after RT. Patients were evaluated from the start of RT to 6 months post‐RT. A mice model with acute radiation‐induced lung injury was established and circulating lymphocytes were measured weekly until 8 weeks after irradiation. Univariate and multivariate analyses were adopted to identify risk factors of RP. Lymphocyte levels significantly decreased (P < .001) in patients before RP symptoms developed that also was able to be seen in the mice model and the values recovered during remission of symptoms. The decrease in lymphocyte count reflected the severity of RP. Meanwhile, CD4+ T lymphocyte count was significantly lower during the occurrence of symptoms in patients with RP than in those without RP (P < .001), and it improved along with RP recovery. Levels of lymphocytes and CD4+ T lymphocyte subsets proved as independent predictors of RP. Here we showed that lower peripheral blood levels of lymphocytes and CD4+ T lymphocyte were associated with an increased risk of RP, which was validated by this mice model, and thus are associated with differences in radiation‐induced lung toxicity among individuals and help identify those who are susceptible to developing RP after RT.
We found lower levels of lymphocyte and CD4+ T lymphocyte linked with radiation pneumonitis and dynamic change of lymphocyte and CD4+ T lymphocyte predict radiation pneumonitis after 182 cases of lung cancer patients with radiation pneumonitis were retrospectively analyzed. The relation of lymphocytes change and radiation pneumonitis was also confirmed in mice model. Therefore, decrease in lymphocyte and CD4+ T lymphocyte was able to act as a predictor of radiation pneumonitis in patients who received thoracic radiotherapy.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This paper reports a strong robustness MEMS QMG with the parallel coupled structure design, for the first time. The motions of the four masses of the gyroscope in the drive and sense directions are ...coupled and connected through different rings to achieve the parallel coupled effect. We demonstrated that the parallel coupled QMG has stronger robustness by numerical analysis, FEA and experiments. We study the kinematic equations of the parallel coupled QMG and compare it with the serial coupled QMG to analyze the effect of the difference in stiffness matrices and damping mismatch on the gyroscope performance and carry out numerical analyses under the conditions of stiffness mismatch and external vibration, and the results show that the parallel coupled QMG has stronger stiffness robustness and vibration robustness. We applied accelerations of different magnitudes and directions to the parallel and serial QMG to simulate the external loads, and the results show that the bandwidth of the parallel QMG is almost unaffected by the acceleration. We fabricated the parallel coupled QMG prototype using the SOG process, and designed circuits to test the performance. The results indicate that the gyroscope is sensitive to small input angles with <inline-formula> <tex-math notation="LaTeX">\mathrm {0.0603 ^{\circ }/s/\surd Hz} </tex-math></inline-formula> ARW and 0.0135∘/s BI at 162 Hz frequency mismatch and <inline-formula> <tex-math notation="LaTeX">30~^{\circ } </tex-math></inline-formula>C temperature compensation. Moreover, the frequency and quality factor of the parallel QMG are little affected by temperature and the bandwidth remains almost constant with good temperature robustness. These results indicate that the parallel structure has the potential to deliver better performance. 2024-0021
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•The designed setup is a useful tool for observing the oil-gas interfacial behavior.•The gas-oil interface of foamy oil was much more stable than that of nonfoamy oil.•The CO2-oil ...film exhibited the highest gas-oil interfacial stability.•Asphaltene properties had an important influence on foamy oil formation.•The asphaltenes from foamy oil contain a greater number of polar functional groups.
Solution gas drive from some heavy oil reservoirs exhibits foamy oil behavior. However, the characteristics of oil that determine whether foamy oil behavior occurs have not been clarified. Therefore, we performed a comprehensive experimental study of gas-oil interfacial properties to provide more in-depth information about foamy oil formation. A new experimental setup for single film stability was designed to investigate the gas-oil interfacial stability and its influencing factors under reservoir conditions. Then, a series of micromodel experiments was conducted in high-pressure etched glass micromodels with foamy and nonfoamy oils to visually study the oil-gas interfacial stability in porous media. Finally, chemical characterization (acid and base number measurements, elemental analyses, nuclear magnetic resonance (NMR), and Fourier transformed infrared spectroscopy (FTIR)) was conducted to reveal the characteristic of foamy oil related to foamy oil formation. The results showed that the gas-oil interfacial stability increased at high oil component concentrations, small interfacial areas, and low temperatures. CO2-oil films exhibited higher gas-oil interfacial stability than N2 and mixed gas (90 mol% CH4 and 10 mol% CO2) for both foamy and nonfoamy oils. A pressure at which the interfacial stability was minimized was observed. In addition, the gas-oil interface of foamy oil was much more stable than that of nonfoamy oil because the asphaltenes from foamy oil contain a greater number of polar functional groups (hydroxyl groups, carboxylic groups, amine, and heterocyclic rings), which adsorb at the oil-gas interface and increase stability. Therefore, a high asphaltene concentration with abundant polar functional groups could be the characteristic of oils responsible for foamy oil formation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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