Green Synthesis of Carbon Nitride-Based Conjugated Copolymer for Efficient Photocatalytic Degradation of Tetracycline.

Upcycling waste plastics into advanced semiconductor photocatalysts provides a new strategy to reasonably and economically solve the huge amount of waste plastics, which remains challenging. Herein, a carbon nitride-based donor-acceptor (D-A) conjugated copolymer by copolymerization of dicyandiamide and terephthalic acid from discarded polyethylene terephthalate (PET) using Zn(OH)2 as catalyst and template at 360-440 °C is synthesized. The morphology and structure of the conjugated copolymer are well regulated by the calcination temperature. The resultant conjugated copolymer exhibits merits of high light absorption and low electron-hole recombination probability. Consequently, it works excellently in the persulfate-based advanced oxidation process for visible light-driven photocatalytic degradation of tetracycline. The kinetic constant (3.4 × 10-2  min-1 ) is 40.5 and 2.3 times that of the conjugated copolymer system and persulfate system, respectively. Furthermore, the reactive species (including •OH, SO4 •- , •O2 - , 1 O2 , and h+ ) and degradation intermediates of tetracycline are analyzed to expound its degradation process. This work not only pioneers design guidelines on upcycling of waste plastics in a sustainable manner, but also provides a facile strategy to synthesize carbon nitride-based D-A conjugated copolymers for the efficient activation of persulfate-based advanced oxidation process in wastewater treatment.

Trends of dental caries in permanent teeth among 12-year-old Chinese children: evidence from five consecutive national surveys between 1995 and 2014.

BACKGROUND: Dental caries have a serious impact on general health and well-being; however, there is a lack of relevant data on the development trends of dental caries in permanent teeth among 12-year-old children in China. We aim to assess long-term trends of dental caries in permanent teeth among 12-year-old children in China and identify the susceptible subgroups based on five consecutive national surveys from 1995 to 2014. METHODS: A total of 88 972 subjects were extracted from five consecutive national surveys (1995, 2000, 2005, 2010, 2014). Standardized dental examinations were conducted and the oral health status of each subject was recorded. The prevalence of Decayed, Missing and Filled teeth (DMF%), mean Decayed, Missing, Filled teeth score (DMFT) and Caries Filling Ratio (CFR) were used as measurement indicators. Cochran-Armitage trend test was used to evaluate the trends in DMF% and CFR, and multivariate linear regression was used to evaluate the trends in DMFT. RESULTS: A V-shaped fluctuating upward trend in DMF% during 1995-2014 was observed (Z = - 13.124, P < 0.001), and the DMF% in 1995-2014 was 21.1%, 15.9%, 16.2%, 21.9% and 24.3%. The trend in DMFT was approximately consistent with DMF% (ß = 0.057, P < 0.001), but the downward volatility appeared in 2014. The DMFT in 1995-2014 was 0.38, 0.28, 0.31, 0.66 and 0.54. A continuously fluctuant trend in CFR was observed during past two decades (Z = 1.927, P > 0.05), and the CFR in 1995-2014 was 17.4%, 22.8%, 19.3%, 23.4% and 15.6%. The DMF% and DMFT of rural children had a larger absolute increase than that of urban children during 1995-2014 (DMF%-urban: Z = - 0.242, P > 0.05; DMF%-rural: Z = - 19.036, P < 0.001; DMFT-urban: ß = 0.035, P < 0.001, DMFT-rural: ß = 0.077, P < 0.001). The DMF% and DMFT in girls were higher than that in boys at each survey year (P < 0.001). CFR of urban children was higher than that of rural children at each survey year (P < 0.001). CONCLUSIONS: Over the past 20 years, DMFT and DMF% of 12-year-old children in China presented V-shaped fluctuant upward trends, with a decline trend from 1995 to 2000 and an upward trend from 2000 to 2014. CFR had no significant improvement. The rural children and girls are the more vulnerable groups in the development of dental caries and need to pay priority. Our study supports the continuation of policies to improve children' oral health.

Multimode Self-Oscillating Vesicle Transformers.

Engineering synthetic materials that mimic the complex rhythmic oscillatory behavior of living cells is a fundamental challenge in science and technology. Up to now, the reported synthetic model system still cannot compete with nature in oscillatory modes and amplitudes. Presented here is a novel alternating copolymer vesicle that exhibits drastic and multimode shape oscillations in real time, which are controlled by polymer concentrations and driven by the Belousov-Zhabotinsky oscillatory reaction, including swelling/deswelling, twisting/detwisting, stretching/shrinking, fusion/fission, and multiple division. Some of them, especially the fission oscillation, have not been observed before. In addition, the oscillation magnitude with regard to diameter is much larger than that of previously reported self-oscillating vesicles. Such a self-oscillating vesicle transformer would extend the complexity and capacity of membrane deformations in synthetic systems, approaching those of natural cells.

Stable Aqueous Foams from Cellulose Nanocrystals and Methyl Cellulose.

The addition of cellulose nanocrystals (CNC) greatly enhanced the properties of methylcellulose (MC) stabilized aqueous foams. CNC addition decreased air bubble size, initial foam densities and drainage rates. Mixtures of 2 wt % CNC + 0.5 wt % MC gave the lowest density foams. This composition sits near the onset of nematic phase formation and also near the overlap concentration of methylcellulose. More than 94% of the added CNC particles remained in the foam phase, not leaving with the draining water. We propose that the nanoscale CNC particles bind to the larger MC coils both in solution and with MC at the air/water interface, forming weak gels that stabilize air bubbles. Wet CNC-MC foams were sufficiently robust to withstand high temperature (70 °C for 6 h) polymerization of water-soluble monomers giving macroporous CNC composite hydrogels based on acrylamide (AM), 2-hydroxyethyl methacrylate (HEMA), or polyethylene glycol diacrylate (PEGDA). At high temperatures, the MC was present as a fibrillar gel phase reinforced by CNC particles, explaining the very high foam stability. Finally, our CNC-MC foams are based on commercially available forms of CNC and MC, already approved for many applications. This is a "shovel-ready" technology.

High-level hemicellulosic arabinose predominately affects lignocellulose crystallinity for genetically enhancing both plant lodging resistance and biomass enzymatic digestibility in rice mutants.

Rice is a major food crop with enormous biomass residue for biofuels. As plant cell wall recalcitrance basically decides a costly biomass process, genetic modification of plant cell walls has been regarded as a promising solution. However, due to structural complexity and functional diversity of plant cell walls, it becomes essential to identify the key factors of cell wall modifications that could not much alter plant growth, but cause an enhancement in biomass enzymatic digestibility. To address this issue, we performed systems biology analyses of a total of 36 distinct cell wall mutants of rice. As a result, cellulose crystallinity (CrI) was examined to be the key factor that negatively determines either the biomass enzymatic saccharification upon various chemical pretreatments or the plant lodging resistance, an integrated agronomic trait in plant growth and grain production. Notably, hemicellulosic arabinose (Ara) was detected to be the major factor that negatively affects cellulose CrI probably through its interlinking with ß-1,4-glucans. In addition, lignin and G monomer also exhibited the positive impact on biomass digestion and lodging resistance. Further characterization of two elite mutants, Osfc17 and Osfc30, showing normal plant growth and high biomass enzymatic digestion in situ and in vitro, revealed the multiple GH9B candidate genes for reducing cellulose CrI and XAT genes for increasing hemicellulosic Ara level. Hence, the results have suggested the potential cell wall modifications for enhancing both biomass enzymatic digestibility and plant lodging resistance by synchronically overexpressing GH9B and XAT genes in rice.

Critical role of benthic fauna in enhancing nanoplastics removal in constructed wetland: Performance, fate and mechanism.

The presence of nanoplastics (NPs) in wastewater poses a considerable risk to ecosystems. Although constructed wetlands (CWs) have the potential to removal NPs, their efficiency is limited by insufficient consideration of ecosystem integrity. Herein, three typical benthic fauna (Corbicula fluminea, Chironomus riparius and Tubifex tubifex) were added to CWs to improve the ecological integrity of CWs, and further enhance the ecological benefits. Results indicated that the addition of C. fluminea, C. riparius and T. tubifex increased NPs removal by 19.14 %, 17.02 %, and 15.76 % than that without benthic faunas, respectively. Based on fluorescence signal analysis, the presence of benthic fauna could intake NPs, and enhanced the adsorption of NPs by plants. The addition of C. fluminea significantly increased catalase (1541.82 ± 41.35 U/g), glutathione S-transferase (0.34 ± 0.02 U/g), and superoxide dismutase (116.33 ± 6.91 U/g) activities (p < 0.05) as a defense mechanism against NPs-induced oxidative stress. Metagenomic analysis revealed that the abundances of key enzymes involved in glycolysis, the tricarboxylic acid cycle, and polystyrene metabolism pathways were increased when C. fluminea was added, corresponding to the microbial degradation of NPs. Overall, the results of this study implied that the benthic fauna can efficiently remove NPs from wastewater in CWs.

Anthocyanidin-Loaded Superabsorbent Self-Pumping Dressings for Macrophage Immunomodulation and Diabetic Wound Healing.

Management of diabetic chronic wound exudate is a serious challenge in healthcare worldwide since it is related to the speed of diabetic wound healing. However, current foam dressings not only absorb fluid to generate swelling and compress the wound to hinder wound healing but also are very thick and less comfortable to use. Herein, a superabsorbent self-pumping ultrathin dressing is reported to accelerate diabetic wound healing by achieving superior exudate absorption and management in an ultrathin state. The self-pumping dressing is composed of a drainage layer loaded with anthocyanidin and a thermoplastic polyurethane absorbent layer embedded with superabsorbent particles. The dressing realizes the self-pumping process of unidirectional exudate draining to the absorption layer through the drainage layer without significant dressing swelling to compress the diabetic wound. The dressing is experimentally proven to unidirectionally drain excessive exudate with inflammatory factors and modulate the conversion of macrophages from M1 to M2 in diabetic wounds, thereby promoting the healing of diabetic skin ulcers faster than commercial foam dressings. Therefore, the dressing provides a new idea and novel method for accelerating diabetic skin ulcer healing.

The critical role of microplastics in the fate and transformation of sulfamethoxazole and antibiotic resistance genes within vertical subsurface-flow constructed wetlands.

Constructed wetlands (CWs) are reservoirs of microplastics (MPs) in the environment. However, knowledge about the impact of MPs on antibiotic removal and the fate of antibiotic resistance genes (ARGs) is limited. We focused on sulfamethoxazole (SMX) as a representative compound to examine the effects of MPs on SMX removal and the proliferation and dissemination of two SMX-related ARGs (sul1 and sul2) in vertical subsurface-flow CW (VFCW) microcosm. The presence of MPs in the substrate was found to enhance the proliferation of microorganisms owing to the large specific surface area of the MPs and the release of dissolved organic carbon (DOC) on MP surfaces, which resulted in a high SMX removal ranging from 97.80 % to 99.80 %. However, the presence of MPs promoted microbial interactions and the horizontal gene transfer (HGT) of ARGs, which led to a significant increase in the abundances of sul1 and sul2 of 68.47 % and 17.20 %, respectively. It is thus imperative to implement rigorous monitoring strategies for MPs to mitigate their potential ecological hazards.

Size-dependent promotion of micro(nano)plastics on the horizontal gene transfer of antibiotic resistance genes in constructed wetlands.

Constructed wetlands (CWs) have been identified as significant sources of micro(nano)plastics (MPs/NPs) and antibiotic resistance genes (ARGs) in aquatic environments. However, little is known about the impact of MPs/NPs exposure on horizontal gene transfer (HGT) of ARGs and shaping the corresponding ARG hosts' community. Herein, the contribution of polystyrene (PS) particles (control, 4 mm, 100 µm, and 100 nm) to ARG transfer was investigated by adding an engineered fluorescent Escherichia coli harboring RP4 plasmid-encoded ARGs into CWs. It was found MPs/NPs significantly promoted ARG transfer in a size-dependent manner in each CW medium (p < 0.05). The 100 µm-sized PS exhibited the most significant promotion of ARG transfer (p < 0.05), whereas 100 nm-sized PS induced limited promotion due to its inhibitory activity on microbes. The altered RP4-carrying bacterial communities suggested that MPs/NPs, especially 100 µm-PS, could recruit pathogenic and nitrifying bacteria to acquire ARGs. The increased sharing of RP4-carrying core bacteria in CW medium further suggested that ARGs can spread into CW microbiome using MPs/NPs as carriers. Overall, our results highlight the high risks of ARG dissemination induced by MPs/NPs exposure and emphasize the need for better control of plastic disposal to prevent the potential health threats.

Modification of fluorescence staining method for small-sized microplastic quantification: Focus on the interference exclusion and exposure time optimization.

Microplastics are an emerging pollutant of global concern, and fluorescence staining as an efficient method for small-sized microplastic qualification often undergoes the serious interference from external environments. The key steps affecting the accuracy of fluorescent staining and the corresponding quality assurance measures were rarely known. Therefore, this study took the Nile Red/DAPI co-staining method as an example to explore the key factors affecting its accuracy and effective measures to avoid interference. High background microplastic contamination in typical lab waters (up to 1115 MP/L), glass fiber filter membrane and glassware were identified as dominant factors affecting microplastic quantification. The background microplastics in lab waters mainly originated from the process of water production and storage. A simple filtration process removed 99% of the background microplastic in the lab waters. After burning at 500 °C for 1 h, the microplastic contamination in the filter membrane and glassware was completely eliminated. H2O2 pretreatment and exposure time caused erroneous microplastic size assessment, and were suggested to be set at 48 h and 10 ms, respectively. During the extraction process, the residue in beakers reached ~ 20% and > 50% for 5 µm and 20 µm sized microplastics, respectively, greatly contributing to the microplastic loss. The comprehensive modified measures caused microplastic concentrations in the three typical samples detected by Nile Red/DAPI co-staining method to decrease by 65.7 - 92.2% and to approach the micro-Raman results. This study clarified the reasons for interfering with quantitative microplastics by fluorescent staining and the effective measures to avoid interference, which were conducive to improving the accuracy of quantitative methods of microplastics.

Chemotactic movement and zeta potential dominate Chlamydomonas microsphaera attachment and biocathode development.

Microalgal cell attaching and biofilm formation are critical in the application of microalgal biocathode, which severs as one of the hopeful candidates to an original cathode in bioelectrochemical systems. Many efforts have been put in biofilm formation and bioelectrochemical systems for years, but the predominant factors shaping microalgal biocathode formation are sketchy. We launched a pair of researches to investigate microalgal attachment and biofilm formation in the presence/absence of applied voltages using Chlamydomonas microsphaera as a model unicellular motile microalga. In this study, we presented how microalga attached and biofilm formed on a carbon felt surface without applied voltages and try to manifest the most important aspects in this process. Results showed that while nutrient sources did not directly regulate cell attachment onto the carbon felt, limited initial nutrient concentration nevertheless promoted cell attachment. Specifically, nutrient availability did not influence the early stage (20-60 min) of microalgal cell attachment but did significantly impact cell attachment during later stages (240-720 min). Further analysis revealed that nutrient availability-mediated chemotactic movements and zeta potential are crucial to facilitate the initial attachment and subsequent biofilm formation of C. microsphaera onto the surfaces, serving as an important factor controlling microalgal surface attachment. Our results demonstrate that nutrient availability is a dominant factor controlling microalgal surface attachment and subsequent biofilm formation processes. This study provides a mechanistic understanding of microalgal surface attachment and biofilm formation processes on carbon felts surfaces in the absence of applied voltages.

Intermittent ultrasound retains cellulases unlock for enhanced cellulosic ethanol with high-porosity biochar for dye adsorption using desirable rice mutant straw.

In this study, optimal ultrasound pretreatment was performed with recalcitrance-reduced rice mutant straw to effectively extract lignin and hemicellulose for improved cellulose accessibility. Intermittent ultrasound-assistant enzymatic hydrolyses were followed to maintain more cellulases unlock and less cellulose surface block with lignin for raised hexose yield at 81 % (% cellulose) and bioethanol concentration at 9.9 g/L, which was higher than those of other mechanical pretreatments as previously conducted. Using all enzyme-undigestible lignocellulose residues, this work generated the biochar with the highest porosity (SBET at 2971 m2/g) among all biomass-based biochar obtained from previous studies. Furthermore, the biochar were respectively examined with high adsorption capacity for Congo red and methylene blue at 7946 mg/g and 861 mg/g. Therefore, this study has demonstrated a green-like process technology for high-yield bioethanol and high-porosity biochar with full biomass utilization by integrating optimal ultrasound pretreatment with intermittent ultrasound-assistant enzymatic hydrolyses of recalcitrance-reduced lignocellulose in crop straws.

Single-molecular insights into the breakpoint of cellulose nanofibers assembly during saccharification.

Plant cellulose microfibrils are increasingly employed to produce functional nanofibers and nanocrystals for biomaterials, but their catalytic formation and conversion mechanisms remain elusive. Here, we characterize length-reduced cellulose nanofibers assembly in situ accounting for the high density of amorphous cellulose regions in the natural rice fragile culm 16 (Osfc16) mutant defective in cellulose biosynthesis using both classic and advanced atomic force microscopy (AFM) techniques equipped with a single-molecular recognition system. By employing individual types of cellulases, we observe efficient enzymatic catalysis modes in the mutant, due to amorphous and inner-broken cellulose chains elevated as breakpoints for initiating and completing cellulose hydrolyses into higher-yield fermentable sugars. Furthermore, effective chemical catalysis mode is examined in vitro for cellulose nanofibers conversion into nanocrystals with reduced dimensions. Our study addresses how plant cellulose substrates are digestible and convertible, revealing a strategy for precise engineering of cellulose substrates toward cost-effective biofuels and high-quality bioproducts.

In-situ formed nanoscale Fe0 for fenton-like oxidation of thermosetting unsaturated polyester resin composites: Nondestructively recycle carbon fiber.

Thermosetting unsaturated polyester resin (UPR) composites were found widespread industrial applications. However, the numerous stable carbon-carbon bonds in cross-linked networks made them intractable for degradation, causing the large-scale composite wastes. Here a nanoscale Fe0 catalyst in-situ forming strategy was exploited to nondestructively recycle carbon fiber (CF) from UPR composites via Fenton-like reaction. The nano-Fe0 catalyst employed in this strategy activated H2O2 for removing UPR, featuring mild conditions and efficient degradation ability. Aiming at facile growth of the catalyst, a porous UPR was achieved by the hydrolysis of alkalic system. The nanoscale Fe0 catalyst was subsequently formed in-situ on the surface of hydrolyzed resin by borohydride reduction. Benefiting from fast mass transfer, the in-situ grown nano-Fe0 showed more efficient degradation ability than added nano-Fe0 or Fe2+ catalyst during Fenton-like reaction. The experiments indicated that hydrolyzed resin could be degraded more than 90% within 80 min, 80 °C. GC-MS, FT-IR analysis and Density functional theory (DFT) calculation were conducted to explained the fracture processes of carbon skeleton in hydrolyzed resin. Especially, a remarkable recovery process of CF from composites was observed, with a 100 percent elimination of resin. The recycled CF cloth exhibited a 99% strength retention and maintained the textile structure, microtopography, chemical structure, resulting in the nondestructive reclaim of CF. This in-situ formed nanoscale Fe0 catalytic degradation strategy may provide a promising practical application for nondestructively recycle CF from UPR composites.

Augmentation of the maxillary sinus: comparison of bioimplants containing bone morphogenetic protein and autogenous bone in a rabbit model.

OBJECTIVE: To evaluate the effectiveness of various bioimplants used for augmentation of the maxillary sinus floor by means of a rabbit model. MATERIALS AND METHODS: Bone was harvested from the posterior iliac crest of 40 adult New Zealand white rabbits to allow bilateral augmentation of the floor of the maxillary sinus with autogenous bone or other materials. One of the following was grafted to the maxillary sinus of each rabbit: particulated autogenous bone, demineralized bone matrix (DBM), DBM combined with purified bone morphogenetic protein (BMP-DBM bioimplants) and bioimplants consisting of a poloxamer gel with BMP in 1 of 2 different doses. Animals were sacrificed at 2 or 8 weeks. Histologic examination was used to assess biologic healing in the various samples. Histomorphometry was used to demonstrate and quantify bone formation. RESULTS: After 2 weeks, the BMP-containing bioimplants had produced more new bone than any of the other materials. Particulated autogenous bone grafts produced less new bone initially (after 2 weeks), but the amount of bone produced by these grafts gradually increased, to levels comparable to the BMP-containing bioimplants by 8 weeks. For groups in which the poloxamer gel was used as a carrier for BMP or where BMP was used in combination with DBM, the amount of bone generated by 8 weeks was similar to that produced by autogenous bone. CONCLUSION: The rabbit maxillary sinus model allowed evaluation of multiple types of bioimplants that could be suitable for peri-implant maxillary reconstruction. BMP-containing bioimplants demonstrated promise as alternatives to autogenous bone grafts for sinus-augmentation procedures. These bioimplants had more rapid initial bone production than all other materials, including autogenous bone. In the future, such biomaterials may enable earlier placement of dental implants into augmented maxillary sinuses.

Highly Conductive PVA/Ag Coating by Aqueous in Situ Reduction and Its Stretchable Structure for Strain Sensor.

Highly stretchable fiber-based strain sensor is essential to develop various applications in intelligent textiles, biomedical electronics, and integrated circuits. Although several fiber-based strain sensors have been reported, attaining the balance between excellent stretchability, high conductivity, and controllable sensitivity remains challenging. Herein, we present a facile approach for fabricating highly conductive, stretchable, and sensitive fiber strain sensors by synthesizing poly(vinyl alcohol)/Ag nanoparticle composite coating through aqueous in situ reduction on a stretchable fiber with a braided structure. The conductive coating with a flexible structure shows an ultrahigh conductivity of 120 903 S/cm. The unique braided structure and dense conductive Ag network enable the strain sensor to simultaneously exhibit 150% of strain sensing, controllable gauge factor from 1.85 to 8.14 within 65% strain, and a rapid response time of 75 ms. Meanwhile, long-term durability and low hysteresis are other initial features of the fiber-based strain sensor. Most importantly, the fiber-based strain sensor is capable of detecting human motions, including vocal cord vibration, finger movements, walking, and running, exhibiting significant potential in real-time monitoring and intelligent textiles.

Surfactant-enhanced anaerobic acidogenesis of Canna indica L. by rumen cultures.

Polyoxyethylene sorbitan monoolate (Tween 80) was used to enhance the anaerobic acidogenesis of Canna indica L. (canna) by rumen culture in this study. Dose of Tween 80 at 1 ml/l enhanced the volatile fatty acids (VFA) production from the acidogenesis of canna compared to the control. However, Tween 80 at higher dosages than 5 ml/l inhibited the rumen microbial activity and reduced the VFA yield. Response surface methodology was successfully used to optimize the VFA yield. A maximum of VFA yield of 0.147 g/g total solids (TS) added was obtained at canna and Tween 80 concentrations of 6.3g TS/l and 2.0 ml/l, respectively. Dosage of Tween 80 at 1-3.75 ml/l reduced the unproductive adsorption of microbes or enzymes on the lignin part in canna and increased microbial activity. A high VFA production was achieved from canna presoaked with Tween 80, suggesting that the structure of canna was disrupted by Tween 80.

Impacts of aeration management and polylactic acid addition on dissolved organic matter characteristics in intensified aquaponic systems.

Aquaponics as a potential alternative for conventional aquaculture industry has increasingly attracted worldwide attention in recent years. However, the sustainable application of aquaponics is facing a growing challenge. In particular, there is a pressing need to better understand and control the accumulation of dissolved organic matter (DOM) in aquaponics with the aim of optimizing nitrogen utilization efficiency. This study was aiming for assessing the characteristics of DOM in the culture water and the relationship with the nitrogen transformations in different intensified aquaponic systems with hydroponic aeration supplement and polylactic acid (PLA) addition. Two enhancing attempts altered the quantity of DOM in aquaponic systems significantly with a varying DOM content of 21.98-45.65 mg/L. The DOM could be represented by four identified fluorescence components including three humic -like materials (83-86%) and one tryptophan-like substance (14-17%). The fluorescence intensities of humic acid-like components were decreased significantly after the application of intensifying strategies, which indicating that two enhancing attempts possibly affected humic acid-like fluorescence. Variation of optical indices also suggested the reductions of water DOM which could be impacted by the enhancing nitrogen treatment processes. These findings will benefit the potential applications and sustainable operation of these strategies in aquaponics.

Genetic loci simultaneously controlling lignin monomers and biomass digestibility of rice straw.

Lignin content and composition are crucial factors affecting biomass digestibility. Exploring the genetic loci simultaneously affecting lignin-relevant traits and biomass digestibility is a precondition for lignin genetic manipulation towards energy crop breeding. In this study, a high-throughput platform was employed to assay the lignin content, lignin composition and biomass enzymatic digestibility of a rice recombinant inbred line population. Correlation analysis indicated that the absolute content of lignin monomers rather than lignin content had negative effects on biomass saccharification, whereas the relative content of p-hydroxyphenyl unit and the molar ratio of p-hydroxyphenyl unit to guaiacyl unit exhibited positive roles. Eight QTL clusters were identified and four of them affecting both lignin composition and biomass digestibility. The additive effects of clustered QTL revealed consistent relationships between lignin-relevant traits and biomass digestibility. Pyramiding rice lines containing the above four positive alleles for increasing biomass digestibility were selected and showed comparable lignin content, decreased syringyl or guaiacyl unit and increased molar percentage of p-hydroxyphenyl unit, the molar ratio of p-hydroxyphenyl unit to guaiacyl unit and sugar releases. More importantly, the lodging resistance and eating/cooking quality of pyramiding lines were not sacrificed, indicating the QTL information could be applied to select desirable energy rice lines.

Hybrid nanofibrous membranes of PLGA/chitosan fabricated via an electrospinning array.

Hybrid nanofibrous membranes of poly(lactic-co-glycolic acid) (PLGA) and chitosan with different chitosan amounts (32.3, 62.7, and 86.5%) were fabricated via a specially designed electrospinning setup consisting of two sets of separate syringe pumps and power supplies. After soaking in chloroform overnight to dissolve PLGA, the amount of chitosan in the hybrid membranes was determined. The structure, mechanical properties, water uptake, and cytocompatibilities of the nanofibrous membranes were investigated by scanning electron microscopy, tensile testing, incubation in phosphate buffer solution, and human embryo skin fibroblasts culturing. Results showed that the chitosan amount in PLGA/chitosan membranes could be well controlled by adjusting the number of syringe for electrospinning of PLGA or chitosan, respectively. Because of the introduction of chitosan, which is a naturally hydrophilic polymer, the hybrid PLGA/chitosan membranes after chitosan crosslinking exhibited good mechanical and water absorption properties. The cytocompatibility of hybrid PLGA/chitosan membranes was better than that of the electrospun PLGA membrane. The electrospun hybrid nanofibrous membranes of PLGA and chitosan appear to be promising for skin tissue engineering. The concept of using an electrospinning array to form multicomponent nanofibrous membranes will lead to the creation of novel scaffolds for tissue engineering applications.