Unraveling the influence of surface roughness on oil displacement by Janus nanoparticles

Janus nanoparticles(JNPs)possess great potential in recovering the residual oil from reservoirs,however,the fundamental interaction mechanisms among nanoparticles,the oil,and reservoir wall characteristics remain to be elucidated.In this work,models of oil trapping grooves with different geometric features are subjected to molecular dynamics simulations for investigating the influences of roughness parameters on oil displacement dynamics by JNPs.Four key surface geometry parameters and different degrees of surface hydrophobicity are considered.Our results indicate that JNPs hold an outstanding performance in displacing residual oil on weakly to moderately hydrophobic surfaces.Overall,smaller entry and exit angles,the larger aspect ratio of the oil trapping grooves,and a bigger tip length of the rough ridges lead to superior oil recovery.Among the key geometric parameters,the aspect ratio of the oil trapping grooves plays the dominant role.These insights about the interaction of surface properties and JNPs and the resulting trapped oil displacement could serve as a theoretical reference for the application of JNPs for targeted reservoir conditions.

Preventive effects of chitosan on peritoneal adhesion in rats

AIM： To study the effects of chitosan gel and blending chiston/gelatin film on preventing peritoneal adhesion in rats. METHODS： SD rats were randomly divided into 2 groups, group A treated with chitosan gel and group B with blending chiston/gelatin film. In group A, rats were randomly subdivided into 3 subgroups as groups A1, A2 and A3, and different methods were used to induce peritoneal adhesions at the dead end of vermiform process in each group as follows： Group A1 with trauma, A2 with talc powder and A3 with ligation of blood vessel. In each subgroup, rats were redivided into control group and experimental group whose treated vermiform processes were respectively coated with chitosan gel and normal saline immediately after the adhesioninduced treatments. In group B, all the rats received traumatic adhesion-induced treatments and then were randomly divided into 4 groups （groups B1, B2, B3, B4）. Group B1 served as control group and were coated with normal saline in the vermiform processes immediately after the treatments, and groups B2, B3 and B4 with 100% chitosan film, chitosan film containing 10% gelatin and chiston film containing 50% gelatin, respectively. At 2 and 4 wk after the above treatments, half of the rats in each terminal group were belly opened, and the peritoneal adhesive situation was graded and histopathological changes were examined. RESULTS： （1） In group A, regarding peritoneal adhesion situation： At both 2 and 4 wk after the treatments, for groups A1 and A3, the adhesive grades of experimental groups were significantly lower than those of the control group （2 wk： H = 4.305, P 〈 0.05 for A1, H = 6.743, P 〈 0.01 for A3; 4 wk： H = 4.459, P 〈 0.05 for A1, H =4.493, P 〈 0.05 for A3）. However, of group A2, there was no significant difference between the experimental and control groups （2 wk： H = 0.147, P 〉 0.05; 4 wk： H = 1.240, P 〉 0.05）. Regarding pathological changes： In groups A1 and A3, the main pathological change was fibroplasia. In group A2, the main changes were massive foreign-body giant cell reaction and granuloma formation with fibroplasia of different degrees. （2） In group B, regarding degradation of film： With increase of the blended gelatin concentration, degrading speed of the film accelerated significantly. Regarding peritoneal adhesion situation： At both 2 and 4 wk after the treatments, the adhesive grades of B1 were the lowest among the four subgroups of B （2 wk： H = 29.679, P 〈 0.05; 4 wk： H = 18.791, P 〈 0.05）. At 2 wk after the treatments, the grades of group B2 were significantly lower than that of groups B3 and B4 （H = 4.025, P 〈 0.05 for B2 vs B3; H = 4.361, P 〈 0.05 for B2 vs B4）. At 4 wk, there were no significant differences of the grades between groups B2, B3 and B4. Regarding pathological changes： Inflammatory cell infiltration and fibroplastic proliferation were observed in the local treated serous membranes, which was the mildest in group B1. Slight foreign-body giant cell reactions were also found in groups B2, B3, and B4. CONCLUSION： （1） Chitosan gel has preventive effect on traumatic or ischemic peritoneal adhesion, but no obvious effect on foreign body-induced peritoneal adhesion. （2） Chitosan film may exacerbate the peritoneal adhesion. Blending with gelatin to chitosan film can accelerate the degradation of the film, but can simultaneously facilitate the formation of peritoneal adhesion.

Preventive effect of gelatinizedly-modified chitosan film on peritoneal adhesion of different types

AIM： To comparatively study the preventive effect of gelatinizedly-modified chitosan film on peritoneal adhesions induced by four different factors in rats. METHODS： Chitosan was chemically modified by gelatinization, and made into films of 60 μm in thickness, and sterilized. Two hundred Sprague-Dawley rats were randomly divided into five groups, Sham-operation group （group A）, wound-induced adhesion group （group B）, purified talc-induced adhesion group （group C）, vascular ligation-induced adhesion group （group D）, and infection-induced adhesion group （group E）, respectively. In each group, the rats were treated with different adhesion-inducing methods at the cecum of vermiform processes and then were divided into control and experimental subgroups. Serous membrane surface of vermiform processes were covered with the films in the experimental subgroups, and no films were used in the control subgroups. After 2 and 4 wk of treatments, the abdominal cavities were reopened and the adhesive severity was graded blindly according to Bhatia＇s method. The cecum of vermiform processes were resected for hydroxyproline （OHP） measurement and pathological examination. RESULTS： Adhesion severity and OHP level： After 2 and 4 wk of the treatments, in the experimental subgroups, the adhesions were significantly lighter and the OHP levels were significantly lower than those of the control subgroups in group B （2 wk： 0.199 ± 0.026 vs 0.285 ± 0.041 μg/mg pr, P 〈 0.001; 4 wk： 0.183 ± 0.034 vs 0.276 ± 0.03 μg/mg pr, P 〈 0.001）, D （2 wk： 0.216 ± 0.036 vs 0.274 ± 0.040 μg/mg pr, P = 0.004; 4 wk： 0.211 ± 0.044 vs 0.281 ± 0.047 μg/mg pr, P = 0.003） and E （2 wk： 0.259 ± 0.039 vs 0.371 ± 0.040 μg/mg pr, P 〈 0.001; 4 wk： 0.242 ± 0.045 vs 0.355 ± 0.029 μg/mg pr, P 〈 0.001）, but there were no significant differences in groups A （2wk： 0.141 ± 0.028 vs 0.137 =k 0.026 μg/mg pr, P = 0.737; 4 wk： 0.132 ± 0.031 vs 0.150 ± 0.035 μg/mg pr, P = 0.225） and C （2 wk： 0.395 ± 0.044 vs 0.378 ± 0.043 μg/mg pr, P = 0.387; 4 wk： 0.370 ± 0.032 vs 0.367 ± 0.041 μg/mg pr, P = 0.853）; Pathological changes： In group B, the main pathological changes were fibroplasias in the treated serous membrane surface and in group D, the fibroplasia was shown in the whole layer of the vermiform processes. In group E, the main pathological changes were acute and chronic suppurative inflammatory reactions. These changes were lighter in the experimental subgroups than those in the control subgroups in the three groups. In group C, the main changes were foreign body giant cell and granuloma reactions and fibroplasias in different degrees, with no apparent differences between the experimental and control subgroups. CONCLUSION： The gelatinizedly-modified chitosan film is effective on preventing peritoneal adhesions induced by wound, ischemia and infection, but the effect is not apparent in foreign body-induced adhesion.

Initial effects of inflammation-related cytokines and signaling pathways on the pathogenesis of post-traumatic osteoarthritis

The main pathological change in post-traumatic osteoarthritis （PTOA） is cartilage degeneration, which is closely related to inflammation and oxidative stress. Inflammation can cause degeneration of articular cartilage. Cartilage degeneration can also stimulate the progression of inflammation. It has been found that inflammatory cytokines can participate in the pathological process of cartilage degeneration through multiple signaling pathways, mainly mitogen-activated protein kinase, nuclear transcription factor kappa B, and Wnt-p-catenin signal transduction pathways. This review aimed at exploring the relationship between PTOA and inflammation-related cytokines by introducing the role of proinflammatory cytokines in chondrocyte destruction and extracellular matrix degradation.

Effects of nitrogen content on growth and hydraulic characteristics of peach(Prunus persica L.) seedlings under different soil moisture conditions

A pot experiment was conducted to investigate the effects of nitrogen content [Nl （no fertilizer）, N2 （0.15 g.kg-l）, and N3 （0.3 g.kg 1）] on the growth and the hydraulic characteristics of peach seedlings under different soil moisture conditions （Wl, W2 and W3, in which the soil water content was 45% to 55%, 60% to 70%, and 75% to 80% of the field water capacity, respectively） by using a specialized high pressure flow meter with a root chamber and a coupling, which was connected to plant organs. Leaf area and leaf hydraulic conductivity （KL） increased significantly in the seedlings because of increased soil moisture and N content. KL increased with leaf area. A linear correlation was documented between KL and leaf area. KL was higher in the morning and began to decline sharply after 16：00, at which KL declined after an initial increase. Soil moisture and N content enhanced shoot （Ks） and root （Kr） hydraulic conductivities, thereby improving the low soil moisture condition to a large extent. Ks and Kr of the seedlings were reduced by 32% and 27% respectively in N~, and by 14.7% and 9.4%, respectively in N2, and both in Wb compared with the control treatment. N3 had no significant effect on Ks and Kr under similar conditions. Linear negative correlations were observed between Kr and the excised root diameter as well as between Ks and the shoot stem diameter. The shoot-to-root ratio increased with in- crease in N content. The shoot-to-root ratio in N3 was increased by 14.37%, compared with N1 in W1 as well as by 12% and 4.39% in Wz and W3, respectively. Knowledge of the effects of soil moisture and N fertilizer on hydraulic characteristics and growth is important. Our results provide basic guidelines for the implementation of water-saving irrigation and fertilization management of nursery stock.

Percutaneous vertebroplasty versus percutaneous kyphoplasty for the treatment of delayed post-traumatic vertebral body collapse(Kümmell’s disease) in Chinese patients: a systematic review and meta-analysis

Objective: To compare the clinical efficacy between percutaneous vertebroplasty(PVP) and percutaneous kyphoplasty(PKP) in the treatment of Kümmell's disease in Chinese patients.Methods: The studies using randomized controlled trials to compare clinical efficacy between PVP and PKP in the treatment of Kümmell's disease in Chinese patients were retrieved from Embase, Pubmed, Central, Cinahl, PQDT, CNKI, CQVIP, Wanfang Data, and CBM(from September 2008 to September 2018). Keywords for both Chinese and English search were: percutaneous vertebroplasty, PVP, percutaneous kyphoplasty, PKP, and Kümmell's disease. A total of 132 articles were retrieved based on the search strategy through online database searching and manual searching. Finally, one foreign report and seven Chinese reports were included. After extracting the data, statistical software Review Manager 5.3 was used for data analysis.Results: Through comparison, Cobb angle(95% CI [0.54, 4.42), P = 0.01] and Oswestry Dysfunction Index(ODI)(95% CI [0.21, 2.15], P= 0.02) of PKP group was smaller than that of PVP group. Postoperative anterior vertebral body height of the PKP group was better than PVP group(95% CI [-1.27,-0.66], P < 0.001]. However, the PVP group had shorter operation time than PKP group(95% CI [-13.48,-7.43), P = 0.001]. In the other outcome measures, including Visual Analogue Scale(VAS) score(95% CI [-0.04, 0.27), P = 0.15), cement volume(95% CI [-0.82, 0.32], P = 0.39) and cement leakage(95% CI [0.90, 2.76], P = 0.11), there was no significant differences between the two procedures.Conclusions: At this stage, there is sufficient evidence to support that PKP is better than PVP in the treatment of Kümmell's disease in Chinese patients. Although PVP surgery requires much less operation time, PKP has better postoperative radiological results and lower ODI. Moreover, both of them had similar clinical results(e.g., analgesic effects, cement dosage, and leakage rate). Further evidence is dependent on the emergence of randomized controlled trials with higher quality and larger sample sizes in the future.

Control of surface wettability via strain engineering

Reversible control of surface wettability has wide applications in lab-on-chip systems, tunable optical lenses, and microfluidic tools. Using a graphene sheet as a sam- ple material and molecular dynamic simulations, we demon- strate that strain engineering can serve as an effective way to control the surface wettability. The contact angles 0 of water droplets on a graphene vary from 72.5° to 106° under biaxial strains ranging from -10% to 10% that are applied on the graphene layer. For an intrinsic hydrophilic surface （at zero strain）, the variation of 0 upon the applied strains is more sensitive, i.e., from 0° to 74.8°. Overall the cosines of the contact angles exhibit a linear relation with respect to the strains. In light of the inherent dependence of the contact an- gle on liquid-solid interfacial energy, we develop an analytic model to show the cos 0 as a linear function of the adsorption energy Eads of a single water molecule over the substrate sur- face. This model agrees with our molecular dynamic results very well. Together with the linear dependence of Eads on bi- axial strains, we can thus understand the effect of strains on the surface wettability. Thanks to the ease of reversibly ap- plying mechanical strains in micro/nano-electromechanical systems, we believe that strain engineering can be a promis- ing means to achieve the reversibly control of surface wetta- bility.

rhBMP in lumber fusion for lumbar spondylolisthesis: A systematic review and meta-analysis

Purpose: To compare the efficacy and safety of recombinant human bone morphogenetic protein (rhBMP) and iliac crest autograft in the fusion treatment of lumbar spondylolisthesis. Methods: The studies using randomized con trolled trials to compare the rhBMP with iliac crest autograft in the treatment of lumbar spondylolisthesis were retrieved from Embase, Pubmed, ProQuest dissertations & theses (PQDT), China national knowledge infrastructure (CNKI), Chinese Biomedical Database, Wanfang Data, Cochrane Library (from March 1998 to March 2018). Postoperative fusion rate, clinical success rate, postoperative intervertebral height, complications, operation time, blood loss and duration of hospitalization were chosen as the outcome indicators. Methodological quality of the trials was critically assessed, and releva nt data were extracted. Statistical software Revman 5.3 was used for dataanalysis. Results: Eleven articles were included in the meta-analysis. The results showed that, comparing the efficacy of rhBMP with iliac crest autograft, statistical significance was found in the 24-month fusion rate post operation [95% CI (1.38, 24.70), p = 0.02] and operation time [95% CI (-14.22,-2.08), p = 0.008]. There is not sufficient evidence for statistical differences in the remaining indicators. Conclusion: The current literature shows rhBMP is a safe and effective grafting material in the treatment of lumbar spondylolisthesis. Further evidenee is dependent on the emergence of more randomized controlled trials with higher quality and larger sample sizes in the future.