During the past decade, self-assembly of saccharide-containing amphiphilic molecules toward bioinspired functional glycomaterials has attracted continuous attention due to their various applications ...in fundamental and practical areas. However, it still remains a great challenge to prepare hierarchical glycoassemblies with controllable and diversiform structures because of the complexity of saccharide structures and carbohydrate-carbohydrate interactions. Herein, through hierarchical self-assembly of modulated amphiphilic supramolecular metallocarbohydrates, we successfully prepared various well-defined glyco-nanostructures in aqueous solution, including vesicles, solid spheres, and opened vesicles depending on the molecular structures of metallocarbohydrates. More attractively, these glyco-nanostructures can further transform into other morphological structures in aqueous solutions such as worm-like micelles, tubules, and even tupanvirus-like vesicles (TVVs). It is worth mentioning that distinctive anisotropic structures including the opened vesicles (OVs) and TVVs were rarely reported in glycobased nano-objects. This intriguing diversity was mainly controlled by the subtle structural trade-off of the two major components of the amphiphiles, i.e., the saccharides and metallacycles. To further understand this precise structural control, molecular simulations provided deep physical insights on the morphology evolution and balancing of the contributions from saccharides and metallacycles. Moreover, the multivalency of glyco-nanostructures with different shapes and sizes was demonstrated by agglutination with a diversity of sugar-binding protein receptors such as the plant lectins Concanavalin A (ConA). This modular synthesis strategy provides access to systematic tuning of molecular structure and self-assembled architecture, which undoubtedly will broaden our horizons on the controllable fabrication of biomimetic glycomaterials such as biological membranes and supramolecular lectin inhibitors.
This paper provides an H∞ robust control strategy for a permanent magnet synchronous generator (PMSG)-based wind farm to realize subsynchronous resonance suppression (SSR) subject to uncertain system ...distortions and parameter perturbation. Firstly, an eighth-order state space mathematical model of a PMSG-based wind farm is established, including the grid-side converter (GSC), GSC controller, and phase-locked loop (PLL) model. Secondly, the SSR characteristics of a PMSG-based wind farm are analyzed through eigenvalue analysis. Thirdly, a robust subsynchronous damping controller is designed based on eigenvalue analysis of SSR. Finally, the designed robust subsynchronous damping controller is validated with case studies of wind farms. The results show that the controller can increase the stability of PMSG-based wind farm systems and restrain SSR.
A protein Pascal triangle has been constructed as new type of supramolecular architecture by using the inducing ligand strategy that we previously developed for protein assemblies. Although ...mathematical studies on this famous geometry have a long history, no work on such Pascal triangles fabricated from native proteins has been reported so far due to their structural complexity. In this work, by carefully tuning the specific interactions between the native protein building block WGA and the inducing ligand R‐SL, a 2D Pascal‐triangle lattice with three types of triangular voids has been assembled. Moreover, a 3D crystal structure was obtained based on the 2D Pascal triangles. The distinctive carbohydrate binding sites of WGA and the intralayer as well as interlayer dimerization of RhB was the key to facilitate nanofabrication in solution. This strategy may be applied to prepare and explore various sophisticated assemblies based on native proteins.
A Pascal‐triangle lattice is constructed by using a careful selection of protein building blocks with anisotropic shapes and two sets of carbohydrate binding sites. Moreover, the dynamic and exchangeable nature of non‐covalent interactions makes the further manipulation of 2D lattices to 3D crystals possible.
BACKGROUOND: Direct percutaneous endoscopic jejunostomy (DPEJ) is a well-known approach to deliver postpyloric enteral nutritional support to individuals who cannot tolerate gastric feeding. However, ...it is technically difficult, and some case series have reported significant procedural failure rates. The present article describes current indications, successes and complications of DPEJ placement.
A MEDLINE database search was performed to identify relevant articles using the key words "direct percutaneous endoscopic jejunostomy", "percutaneous endoscopic gastrostomy", and "percutaneous endoscopic gastrostomy with a jejunal extension tube". Additional articles were identified by a manual search of the references cited in the key articles obtained in the primary search.
DPEJ is gradually becoming more common in the treatment of patients who cannot tolerate gastric feeding. Differences in patient selection and technique modifications may contribute to the various success rates reported. Failure is most often due to inadequate transillumination or gastroduodenal obstruction. Currently, there are limited data to evaluate the safety and effectiveness of DPEJ.
The clinical use of DPEJ is increasing. With appropriate care and expertise, DPEJ may prove to be reliable and safe.
Ionic-conductive polymers with highly ordered, phase-separated structure are the promising materials used as anion exchange membranes (AEMs), thanks to their pronounced ion mobility. In this study, ...apart from imidazolium-functionalized hydrophilic pendants, additional octyl and perfluorooctyl-containing grafts were tethered to the polymer backbone and the resultant structure-morphology relationships were systemically investigated. The results revealed that the introduction of hydrophobic side chains as well as the corresponding hydrophobicity plays an important role in the formation of a phase-separated morphology in the membrane. AEMs containing perfluorooctyl-containing pendants (PPO-x-Imy8Fz) exhibited a pronounced microphase-separated morphology with ion clusters of about 2–5 nm size and a spacing of ∼6 nm, while the membranes with octyl pendants (PPO-x-Imy8Cz) or no additional hydrophobic side chains (PPO-x-Im) only showed indistinct or no phase separation. In addition, PPO-x-Imy8Fz AEMs showed better ion conductivity and suppressed water absorption, thereby exhibiting a good balance between water uptake and ion conductivity. The results of this study provide an efficient strategy to guide the architectural design of high-performance AEMs.
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•Perfluorinated side chain was employed to promote the microphase separation of AEM.•The morphology of AEM showed high dependence on the existence of additional hydrophobic graft and its hydrophobicity.•PPO-x-Imy8Fz AEMs showed a good balance between water uptake and ion conductivity.
Chronic radiation enteritis (CRE) is one of the most feared complications of abdominal or pelvic radiation therapy and the treatment of CRE is difficult and often controversial. Recent progress in ...molecular biology has shed some light on the pathogenesis of CRE, which is characterized by fibrosis. The purpose of this article is to summarize the current state of knowledge of molecular aspects of radiation induced intestinal fibrosis and to discuss potential therapeutic targets.
A review of the up-to-date published literature involving the possible molecular cascades in radiation-induced intestinal fibrosis and prospective targets for CRE were performed using the Pub-Med search engine.
Fibrosis development is correlated with transforming growth factor β1 (TGF-β1) and its downstream effector Smad3, which stimulates fibrogenic downstream mediators, such as connective tissue growth factor (CTGF). Ras homologue (Rho) and Rho-associated kinase (ROCK) signaling pathway have been shown to play important roles in the development of CRE. The inhibition of these pathways ameliorated radiation-induced intestinal fibrosis in vitro and in animal studies; however, the relationship between the Smad3 and Rho signaling pathways has not been elucidated.
Rho/ROCK and TGF-β1/Smad3 signaling pathways have been shown to play a key role in intestinal fibrogenesis, which might provide with effective possibilities for clinical intervention. Understanding the cooperation between Smad3 and Rho, may therefore be critical to our overall understanding of fibrosis development and maintenance of CRE.
•An H∞ damping controller is developed for the DFIG based WF to mitigate SSI.•The robust stability (RS) and robust performance (RP) of the system are validated by the µ analysis.•The performance of ...the H∞ damping controller is demonstrated by time domain simulations.•The worst case scenario shows the superior performance of the H∞ damping controller.
This paper proposes an H∞ damping controller for the doubly-fed induction generator (DFIG) based wind farm (WF) to mitigate sub-synchronous control interactions (SSCI) with series capacitor compensated lines. A multi-input multi-output (MIMO) uncertain state-space model is developed to reflect the main SSCI characteristics considering the uncertainties of wind speed, series compensation (SC) levels and system parameters. The SSCI is analyzed using the eigenvalue analysis of the uncertain system model. In order to damp the SSCI between the WF and series capacitor compensated lines under uncertainties, an H∞ damping controller is designed for the rotor side converter (RSC). The weighting functions are designed to meet the mitigation requirements of sub-synchronous oscillation currents and output power. The robust stability (RS) and robust performance (RP) of the system are validated by the µ analysis. The performance of the H∞ damping controller is demonstrated by time domain simulations of a 90 MW wind farm model with different wind speed, and SC levels. The case study with 6 m/s wind speed and 70% SC level shows superior performance of the H∞ damping controller.
Biodiversity losing and unreasonable use of nature resources are two important environmental issues. In order to protect biodiversity rescources,many countries have established numerous nature ...reserves and other types of protected areas. However,degradation of natural resources is a big challenge in conservation projects,and we cannot prohibit all the activities associated with economic development in the conserved areas,particularly in southwest China. There is a serious conflict between two aspects. One aspect is the rich biodiversity,increasing its importance for conservation. The other is the backward economy that requires more resources for local development. Therefore,land zoning is an important approach that can reduce conflict by partitioning the landscape into various land use units that are managed according to different levels of human activity. Our research focuses on the Three Parallel Rivers of the Yunnan Protected Area. We present a systematic methodology that integrates vegetation plot data with Geographic Information Systems( GIS) using a multi-criteria decision analysis( MCDA) technique to guide a zoning scheme. The vegetation plot data include species richness,rarity of vegetation,number of endangered plant species,ranking of endangered species,and quality of habitat. Based on these data,the protection value scores for the sub-vegetation in northwest Yunnan were obtained. Then altitude,distance to villages,distance to roads and distance to rivers were used as the impact factors to simulate the pattern of protection cost.The protection value and protection cost were integrated to generate a final combined suitability map. A K-means cluster analysis was performed to classify the suitability map into four priority levels. In this study,the area considered under level 1 was 16983 km~2,accounting for 25. 58% of the total research area. The targeted areas for protection in level 1 included sub-vegetation of monsoon evergreen broad-leaved forest,cold-temperate coniferous forest,alpine and sub-alpine meadow,cold-temperate shrub,and areas covered by snow and water; level 1 accounts for the most important protection areas where important forest ecosystems,grassland ecosystems,and wetland ecosystems can be found. The areas under level 1 can be further divided into six parts. Part 1 is located northeast of Zhongdian; the average altitude is above 3000 m,and it is covered by cold-temperate coniferous forest. Part 2 comprises most areas of Denqing and northern Weixi,which include the Meili and Baima snowmountains. Part 3 forms the main part of the Nu mountains in Yunnan,and it appears as a line. Part 4 is located in Gongshan and Fugong,including the main part of Gaoligong National Nature Reserve. Part 5 comprises regions of southeast Zhongdian,northwest Ninglang,and northeast Lijiang. Although this part has a large area,its distribution is scattered. Part 6 comprises the Erhai Lake in Dali,which has a small area,and it is the only critical conservation region southeast of our research area. Level 2 accounts for the main areas for the conservation of forest ecosystems. Therefore,we suggested that an equal protection effort as level 1 should be made. Level 3 had a low protection value and we could use it as a buffer zone. Level 4 had no protection value and was considered the traditional land use area. According to the priority levels,we determined the area under level 1 as the priority area. We believe that our results will be useful as a reference for extension of reserves in northwest Yunnan in the future.
We proposed the deprotection-induced block copolymer self-assembly (DISA); that is, the deprotection of hydroxyl groups resulted in in situ self-assembly of glycopolymers. In the previous studies, ...block copolymers soluble in common organic solvents were employed as the starting material. In this paper, by using the protected glyco-block containing preassembled glycovesicles in water as the starting material, we moved forward and made two exceeding achievements. First, we have observed a deprotection-induced morphology transition triggered by alkali in water. The carbohydrate–carbohydrate interactions were considered to contribute to such a morphology transition during deprotection. Second, lipase was found to be an efficient enzymatic trigger in the sugar deprotection, which motivates the immune-application of this morphology transition process. When lipase and a model antigen, ovalbumin (OVA), were encapsulated inside the glycovesicles, the deprotection of sugars by lipase induced the transition of vesicles to micelles and the lipase and OVA were released accordingly. When glycovesicles were internalized by dentritic cells (DCs), the lipase from lysosomes efficiently induced the release of OVA and presentation of antigen to T cells. During the process, lysosomal lipase performed as a trigger on the deprotection of sugars and the release of protein without any other reagents. The significance of this design is that as a delivery vehicle, the protected glycovesicles not only avoided unnecessary immune activation but also worked with the released OVA together; that is, the glycovehicle successfully activated DCs and improved the presentation efficiency of T cells remarkably.
Aim
The objective of this study was to explore the correlation between the expression of miRNA-135a and Bach1 in colorectal cancer tissue and the patient's clinical information.
Methods
Sixty ...patients with colorectal carcinoma were treated as a control group. Real-time quantitative polymerase chain reaction assays and immunohistochemistry methods were performed to detect the expression of miRNA-135a and Bach1 in 60 colorectal carcinomas and adjacent normal tissues, and the clinical and pathologic classifications were also investigated. SPSS 19.00 software was used. All data are represented as mean ± SD of 3 independent experiments. P < 0.05 was considered statistically significant.
Results
miRNA-135a expression levels increased significantly in colon cancer tissues compared with the nontumor control tissues (P < 0.01). miRNA-135a expression levels were higher in stage III/IV than in stage I/II colon cancer patients. The expression level of Bach1 in colorectal cancer was significantly lower (P < 0.01). Bach1 and miRNA-135a were negatively correlated.
Conclusions
The levels of miRNA-135a and Bach1 were opposite: the overexpression of miRNA-135a might downregulate the expression of Bach1, which might be involved in the pathogenesis of colorectal cancer.
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