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SAGD (Steam Assisted Gravity Drainage) is used in Canadian fields where there are interlayers that impede steam chamber development and thus impede production. Many experiments have been conducted on the effect of interlayers on oil recovery. However, the swelling characteristics of interlayers under different conditions, as well as the possible clay mineral transformation and particle migration of clay particles at high temperatures, are rarely studied. In this paper, the swelling characteristics of natural oil sands and artificial clay samples were studied by high temperature hydration swelling experiments to obtain a better comparison. The effects of temperature, pressure and solution type on the swelling rate of oil sand were studied. The uniaxial compressive strength of the core in the presence of clay was studied by the scribe test. In addition, before and after the aging test at 220 °C and 2.5 MPa, the clay mineral composition was studied by the X-ray diffraction method, and the mineral transformation was proved. Finally, the impact of clay swelling on oil production is investigated by simulating the particle migration effect while considering the swelling effect. The results show that the swelling rate of oil sand increases with the increment of temperature and the decrement of pressure. The swelling rate of an artificial clay sample in distilled water is the highest, while a 1% KCl + 1% CaCl2 solution has the best swelling inhibition effect. This study aims to provide new insights into reservoir damage research during SAGD development. [ABSTRACT FROM AUTHOR]

In this paper, we focus on a network system which describes spatiotemporal dynamics of single species population at different patches since species can have different features in various life stages and different behaviors in various spatial environments. With the effect of time delay and spatial dispersion, homogenous, periodic and spatiotemporally nonhomogeneous distributions are identified. The stability analysis is carried out for the discrete-space and continuous-time network on single species with time delay and the Hopf bifurcation of the single species population model in a network is explored. Formulas for determining the direction of Hopf bifurcation are derived by using the center manifold method and the normal form theorem. It is found that the network can generate spatial patterns only when time delay is present. Finally, numerical simulations are performed which agree well with our theoretical result, i.e. this discrete-space and continuous-time model admits regular temporal patterns since the delay induces Hopf bifurcations with network structure. [ABSTRACT FROM AUTHOR]

• Polyphenols could inhibit the oxidative degradation of HSA in the order: Hto > Bra > Hte. • Three polyphenols bound to HSA by static quenching mechanism with moderate binding affinity. • The binding of polyphenols to HSA resulted in the conformational changes of HSA. • Polyphenols bound to the site I of HSA through non-covalent bonds. Brazilin (Bra), hematoxylin (Hto) and hematein (Hte) are structurally similar polyphenols having rich biological activities, but their antioxidant ability has not been well studied. Here, their protective ability against human serum albumin (HSA) oxidative degradation were investigated using 2,2′-Azobis (2-methylpropionamidine) dihydrochloride (AAPH), NaClO and Fenton like reactions methods. The results indicated that polyphenols inhibited the oxidative injuries of HSA in the order: Hto > Bra > Hte. Additionally, the biological effects of polyphenols were mostly influenced by their binding to protein. Therefore, the structure-affinity relationships of polyphenols binding to HSA were also explored. Fluorescence experiments indicated that polyphenols bound to HSA through static quenching mechanism. Furthermore, some conformational changes of HSA could be observed in the presence of polyphenols. Altogether, molecular structure of polyphenols played a significant role in their protective effect against HSA oxidative damage and binding ability, which provided fundamental insights into their application as health care foods. [ABSTRACT FROM AUTHOR]

• Brazilin bound with BSA through a static quenching procedure with moderate binding affinity. • Hydrophobic and hydrogen bond interactions played a major role in the binding of Brazilin to BSA. • The binding of Bra to BSA induced some conformational changes of BSA. • Brazilin showed anti-amyloidogenic activity and disaggregation activity. Free and active concentration of drug in the blood plays a vital role in the disease treatment. Binding of drug to serum albumin, an important transport protein in plasma, usually improves its aqueous solubility, stability and bioactivity. Brazilin (Bra) is a natural compound extracted from Caesalpinia sappan with numerous pharmacological applications, while the behavior of Bra in circulatory system is still unknown. Therefore, in the present work, we firstly examined the interaction of Bra with bovine serum albumin (BSA) using various spectroscopic and computer simulation techniques. The static quenching mechanism and moderate binding affinity (2.18 × 104 M−1 at 298 K) were obtained through fluorescence spectroscopic measurement. Thermodynamic analysis results indicated that hydrophobic interactions and hydrogen bonds played a major role in the binding process. Site marker competitive experiments and molecular simulation suggested that the probable Bra-binding position was located in subdomain IIA of BSA. UV–vis absorption, circular dichroism (CD) and dynamic light scattering (DLS) experiments suggested the conformational changes of BSA induced by Bra. Additionally, the potential of Bra to inhibit the formation of amyloid fibrils, in vitro , has also been analyzed. Thioflavin T (ThT) binding, 8-anilino-1-naphthalenesulfonic acid (ANS) binding, Congo red binding, DLS, CD, fluorescence microscopic image, atomic force microscopy (AFM), size-exclusion chromatography (SEC) and native gel-electrophoresis methods were used, and all confirmed the anti-amyloidogenic behavior of Bra. In short, our findings have provided some important insights into the binding mechanism of Bra with BSA, and would be helpful in designing suitable agents against amyloid diseases. [ABSTRACT FROM AUTHOR]

• NGDC/NHDC bound to BSA through a static quenching, and NGDC had stronger binding affinity to BSA compared with NHDC. • Hydrophobic interactions and hydrogen bonds played a major role in the binding of NGDC/NHDC to BSA. • The interaction between NGDC/NHDC and BSA induced some conformational changes of BSA. • NGDC/NHDC showed obvious anti-glycation activities in a dose-dependent manner. The interactions of two dihydrochalcones (naringin dihydrochalcone (NGDC) and neohesperidin dihydrochalcone (NHDC)) with bovine serum albumin (BSA) and their anti-glycation effects were studied utilizing multiple spectral methods and molecular simulation technique. The findings proved that NGDC/NHDC could use a static quenching mechanism to reduce the intrinsic fluorescence of BSA, and the interaction between NGDC/NHDC and BSA was a spontaneous behavior with the binding constant ranging from 104 to 105 M −1. Furthermore, NGDC and NHDC mainly interacted with the site I (subdomain IIA) of BSA via hydrophobic interactions and hydrogen bonds, endorsed by molecular docking study. A conjoint analysis of circular dichroism, three-dimensional fluorescence, dynamic light scattering, and UV-vis absorption spectra confirmed that NGDC/NHDC could induce some alterations in the spatial conformation and microenvironment of BSA. Additionally, NGDC and NHDC inhibited the non-enzymatic glycation of BSA by decreasing the contents of advanced glycation end products (AGEs), trapping methylglyoxal/glyoxal and maintaining the stability of the natural conformation of the protein. Overall, these findings were highly beneficial in disclosing the interaction mechanisms between dihydrochalcones and BSA and providing valuable information for the application of dihydrochalcones as functional food ingredients. [Display omitted] [ABSTRACT FROM AUTHOR]

Objective: To retrospectively analyze and compare the relationship between the success rate of patient‐derived xenograft (PDX) modeling of osteosarcoma and prognosis (3‐year overall survival rate and disease‐free survival rate) and incidence of lung metastasis. Methods: The sample group consisted of 57 osteosarcoma patients with definite pathological diagnoses from Shanghai General Hospital from 2015–2017. PDX models in 57 patients were analyzed by retrospective analyses. Among the patients currently inoculated, 20 were tumorigenic in the PDX model, and 37 were nontumorigenic. According to the tumorigenicity of PDXs, the corresponding osteosarcoma patients were divided into two groups. The effects of clinically related indicators on the model were retrospectively compared. The patients were followed, and the 3‐year survival, 3‐year disease‐free survival (DFS), and lung metastasis rates were collected. The relationship between the modeling success and patient prognosis was investigated. Results: In the chemotherapy‐treated group, the PDX modeling success rate was 17.4%, and in the nonchemotherapy group, the success rate was 47.1%. The success of PDX modeling was related to whether patients received chemotherapy. The success rate of PDX modeling is significantly reduced after receiving chemotherapy. The 3‐year overall survival rate of the PDX‐grafted group was 49.23%, and that of the PDX‐nongrafted group was 65.71%. There was a significant difference between the two groups, showing a strong negative correlation between the 3‐year survival rate and the success rate of the PDX model. The 3‐year disease‐free survival rate of the PDX‐grafted group was 29.54%. The 3‐year DFS of the PDX‐nongrafted group was 50.34%. There was a significant difference between the two groups. Lower grafted rates indicate a higher DFS rate. The incidence of lung metastasis in the PDX‐grafted group was 32.4%, and that in the nongrafted group was 13.1%. There was a significant difference between the two groups. The successful establishment of the PDX model indicates that patients are more likely to have lung metastases. Conclusions: The success of PDX modeling often indicates poor prognosis (low 3‐year overall survival rate and disease‐free survival rate) and a greater possibility of lung metastasis. Therefore, PDX modeling in osteosarcoma patients can accurately predict the prognosis of patients and the risk of lung metastasis in advance to help us develop better therapeutic strategies. [ABSTRACT FROM AUTHOR]

Flavonoid compounds have anti-diabetic activity, which can control blood glucose levels by inhibiting α-glucosidase activity. In this paper, the inhibition mechanisms between four flavonoid compounds and α-glucosidase were studied by multispectroscopic methods and molecular docking. The results showed that the inhibitory activities of flavonoid compounds were higher than that of acarbose, and the sequence of inhibition effect was scutellarein > nepetin > apigenin > hispidulin > acarbose. Also, the synergistic effects of flavonoid compounds combined with acarbose on inhibiting α-glucosidase activity were observed. The fluorescence results showed that flavonoid compounds combined with α-glucosidase to form a stable complex. And the spectral analysis indicated that the microenvironmental and secondary structure of α-glucosidase were changed. The present study demonstrated that the molecular structure of flavonoid compounds played an important role in the inhibition process, namely, scutellarein with more hydroxyl groups on the A-ring might serve as the most effective α-glucosidase inhibitor. [ABSTRACT FROM AUTHOR]

• In vitro the binding study of monascin to BSA was carried out. • Multi-spectral techniques and molecular modeling were adopted. • Monascin could bind to site I of BSA through static quenching mechanism. • Structural changes of BSA were demonstrated by fluorescence, DLS and CD methods. • The antioxidant activity of monascin might be reduced when binding to BSA. Monascin (MS) is a yellow lipid-soluble azaphilonoid pigment identified from Monascus -fermented products with promising biological activities. This work studied interactions between MS and bovine serum albumin (BSA) as well as their influences on the antioxidant activity of MS. Experimental results demonstrated that the fluorescence emission of BSA was quenched by MS via static quenching mechanism and the formed BSA-MS complex was mainly maintained by hydrophobic and hydrogen bond interactions. Meanwhile, the probable binding pocket of MS located near site I of BSA and the corresponding conformational and structural alterations of BSA were determined. Furthermore, the molecular modeling approach was performed to understand the visual representation of binding mode between BSA and MS. It was noticeable that the BSA-MS complex exhibited reduced DPPH radical-scavenging ability, which might be attributed to the restraining effect of BSA on the relevant reaction pathways involved in antioxidation by MS. [ABSTRACT FROM AUTHOR]