A novel MgF2/PDA/S-HA coating on the bio-degradable ZE21B alloy for better multi-functions on cardiovascular application

Recently, functional molecules such as Polydopamine(PDA), Hyaluronic Acid(HA) and heparin have been widely studied in the field of surface modification of magnesium(Mg) alloy stents for better degradation behavior and biocompatibility, but their further application is limited by undesirable anticoagulant function, uncontrollable degradation and easy bleeding, respectively.Regarding to this consideration, a magnesium Fluoride/Polydopamine/Sulphonated hyaluronic acid(Mg F2/PDA/S-HA) composite coating was successfully prepared by applying S-HA with sulfur content of 9.71 wt% on the surface of ZE21B alloy in this study. The results showed that the composite coating with a unique mesh structure not only inherited the anticoagulant effect of sulfonic acid group and the excellent cyto-compatibility of S-HA with high sulfur content, but also significantly improved the corrosion performance of ZE21B alloy.These results indicate a great application potential of the composite coating in the field of cardiovascular biomaterials.

Comparison of paclitaxal vs. sirolimus eluting stents with bio-degradable polymer for the treatment of coronary bifurcation lesions： subgroup analysis from DKCRUSH-I and DKCRUSH-II studies

Background The difference in clinical outcome between paclitaxal-eluting stents （PES） and sirolimus-eluting stents with bio-degradable polymer （SES-BDP） for bifurcation lesions remains unclear. The present study aimed to investigate the one-year clinical outcome after DK crush stenting using PES （maxusTM） MS. SES-BDP （ExcelTM） from our database. Methods A total of 275 patients （90 from the DKCRUSH-I and 185 from the DKCRUSH-II study） were studied. The primary endpoint was the occurrence of major adverse cardiac events （MACE） at 12 months; including cardiac death, myocardial infarction （MI）, or target vessel revascularization （TVR）. The rate of binary restenosis and stent thrombosis served as secondary endpoints. Results At follow-up, minimal luminal diameter （MLD） in the Taxus group was （2.11＋0.66） mm, with resultant increased target lesion revascularization （TLR） 12.2% and TVR 14.4%, significantly different from the Excel group; （2.47±0.56） mm, P 〈0.001, 3.2%, P=0.006, 4.9%, P=0.019, respectively. As a result there was a significant difference in MACE between the Taxus （20.0%） and Excel （10.3%, P=0.038） groups. Overall stent thrombosis was monitored in 11 patients （4.0%）, with five in the Excel group （2.7%） and six in the Taxus group （6.7%）. All stent thrombosis in the Excel group was classified as early, and all were defined as late in the Taxus group. Conclusion The Excel stent had lower rate of stent thrombosis, TLR, TVR, and composite MACE at 12-month after an indexed stenting procedure, compared to the Taxus stent.

Sustainable, thermoplastic and hydrophobic coating from natural cellulose and cinnamon to fabricate eco-friendly catering packaging

Non-degradable polymers cause serious environmental pollution problem,such as the widely-used while unrecyclable coatings which significantly affect the overall degradation performance of products.It is imperative and attractive to develop biodegradable functional coatings.Herein,we proposed a novel strategy to successfully prepare biodegradable,thermoplastic and hydrophobic coatings with high transparence and biosafety by weakening the interchain interactions between cellulose chain.The natural cellulose and cinnamic acid were as raw materials.Via reducing the degree of polymerization(DP)of cellulose and regulating the degree of substitution(DS)of cinnamate moiety,the obtained cellulose cinnamate(CC)exhibited not only the thermalflow behavior but also good biodegradability,which solves the conflict between the thermoplasticity and biodegradability in cellulose-based materials.The glass transition temperature(T_(g))and thermalflow temperature(T_(f))of the CC could be adjusted in a range of 150–200℃ and 180–210℃,respectively.The CC with DS<1.2 and DP≤100 degraded more than 60%after an enzyme treatment for 7 days,and degraded more than 80%after a composting treatment for 42 days.Furthermore,CC had no toxicity to human epidermal cells even at a high concentration(0.5 mg mL^(-1)).In addition,CC could be easily fabricated into multifunctional coating with high hydrophobicity,thermal adhesion and high transparence.Therefore,after combining with cellophane and paperboard,CC coating with low DP and DS could be used to prepare fully-biodegradable heat-sealing packaging,art paper,paper cups,paper straws and food packaging boxes.

Straw bio-degradation by acidogenic bacteria and composite fungi

A composite microbial system, including a strain of Candida tropicalis(W3), a strain of Lactobacillus plantarm(WY3) and three strains of basidiomycete pL104, pL113 and C33, was chosen to degrade corn straw. The final pH was acid owing to the inoculation of acidogenic bacteria, and under this condition the composite fungi system could produce complex enzyme to destroy the compact structure of corn straw. The experimental results showed that the biomass of composite fungi could reach up to maximum when the pH value was 4.5. Through the bio-degradation by combining acidogenic bacteria with the composite fungi system, the cellulose, hemi-cellulose and lignin degradation rates of corn straw powder were 26.36%, 43.30% and 26.96%, respectively. And the gross crude protein content increased 60.41%. This study provided the evidence for the feasibility of developing a composite microbial system with high capability of degrading straw lignocelluloses in order to make reasonable use of straw resource and protect rural eco-environment.

Recent advances using equal-channel angular pressing to improve the properties of biodegradable Mg-Zn alloys

Magnesium alloys are of considerable current interest for use as degradable implants due to their unique properties including biodegrad-ability,biocompatibility,low density and adequate mechanical properties.Nevertheless,there is a need to further improve these properties either by alloying or through the use of appropriate processing.Among the different biodegradable Mg alloys now in use,the Mg-Zn series are of special interest and have been the subject of many research investigations.This is primarily because Zn is an essential element for the human body in addition to its positive effects in improving the mechanical strength and lowering the degradation rate of the implant.The properties of Mg-Zn alloys may be further improved both through the addition of third and fourth alloying elements such as Ca,Ag,Sn or Sr and/or by thermo-mechanical processing where the latter is more environmentally and economically favorable.In practice,procedures based on the application of severe plastic deformation(SPD)are especially suited to produce fine-grained microstructures with improved mechanical,degradation and cell behavior.Equal-channel angular pressing(ECAP)is a popular SPD technique that has the capability of pro-ducing bulk materials that are sufficiently large for use as typical implants.Accordingly,this review is designed to provide a comprehensive summary of the research that has been undertaken on ECAP-processed biodegradable Mg-Zn alloys.

A brief review on natural fiber used as a replacement of synthetic fiber in polymer composites

The use of composites in different sectors has become inevitable due to the enhancement in properties, reduction in the manufacturing cost and suitability to several applications. Among different classifications, polymeric composites are mainly focused on their use as structural components and the selection and composition of reinforcement play a vital role in determining the characteristics of the composite. Although composites are developed with man-made reinforcement in the beginning stage, in the present situation, natural reinforcements have proved excellent results in terms of properties. Hence, nowadays researches are mainly focused on the use of different natural fibers in different forms as reinforcements in polymeric composite. This work presents a brief overview on the properties of natural fiber and natural fiber reinforced composites which is an emerging area in polymer science. Interests in natural fiber is reasonable due to the advantages of these materials compared to others, such as synthetic fiber composites, including low environmental impact and low cost and support their potential to be used. Moreover, the disadvantage of the synthetic and fiber-glass as reinforcement, the use of natural fiber reinforced composite gained the attention of the young scientists, researchers, and engineers and are being exploited as a replacement for the conventional fiber such as glass, aramid, carbon etc. Natural fibers have been proven alternative to synthetic fiber in transportation such as automobiles, railway coaches and aerospace, military, building, packaging, consumer products and construction industries for ceiling paneling, partition boards etc. However, in development of these composites, some drawbacks have also emerged. In this paper, it has been tried to overview all of this together.

Fabrication and Optical Characterization of Palm Fiber Reinforced Acrylonitrile Butadiene Styrene Based Composites: Band Gap Studies

The composite materials are replacing the conventional materials, owing to their excellent properties. The developments of new materials are on the anvil and are thriving day by day. Natural fiber composites such as palm fiber (PF) polymer composites became more enchanting because of their high specific strength, low weight and biodegradability. Mixing of natural fiber like PF with acrylonitrile butadiene styrene (ABS) polymer is finding increased applications. In this work, PF reinforced ABS composites PF-ABS was fabricated by Injection Moulding Machine. The effect of UV-Visible radiation on PF-ABS composites was studied by means of ultraviolet-visible spectroscopy in the wavelength 200 - 1000 nm at room temperature. The present investigation shows that the addition of palm fiber modifies the absorption property of the materials. The absorption ability is maximal for 10% PF-ABS composites while minimal for 20% PF-ABS composites in the visible region of the spectrum. Optical constant like direct band gap energy, Urbach energy and Steepness parameter were determined using absorbance data. The values of direct energy band gap, Urbach energy as well as Steepness parameter were found to be in the range 2.6 - 3.9 eV, 0.40 - 0.85 eV and 0.03 - 0.06, respectively. It was observed that the value of direct band gap energy as well as Urbach energy is higher while the value of Steepness parameter is lower for PF-ABS composites with 10% palm fiber.

Lactic Acid-Sustainable Raw Material for Biodegradable Hot Melt Adhesive: Review

Currently, due to scarcity of hydrocarbon resources and the extensive use of water based, solvent based and hot melt adhesives in wood bonding in furniture industries and packaging industries that demand recyclability, compostability and bio-degradability, recently attention has been concentrated to making these formulations completely bio-based, sustainable and biodegradable. Biodegradable hot melt adhesives (HMAs) prepared from natural sources have a potential for use in furniture and packaging industries because of an increase in awareness of environmental issues, the replacement of conventional petroleum-derived hydrocarbon raw materials by renewable, biodegradable and sustainable materials has developed. In terms of environmental issues, such as climate crisis due to an increase of carbon dioxide emission, attempts have been made to produce HMAs using non-hydrocarbon resins, such as polylactic acid (PLA)-based resins, containing no petroleum as a raw material. Polylactic acid was prepared by self-condensation reactions of lactic acid or by lactide ring opening polymerisation, and used for packaging materials, sanitary pads, diapers etc., especially adhesives owing to its excellent processability and the excellent mechanical properties of its HMAs products. Therefore, recently the use of PLA materials as a substitute for non-biodegradable hydrocarbon-based polymers can be considered to be environmentally favourable. Here, we discussed the various uses of PLA as a sustainable and bio-degradable and sustainable hot melt adhesive.

A Polymerase Chain Reaction Based DNA Fingerprinting Technique: Amplified Fragment Length Polymorphism for Molecular Typing of Perchlorate Reducing Bacteria

Genetic profiling of environmentally important organisms is very essential for easy identification of biodegrading bacteria. In the previous study, we have reported the perchlorate biodegrading bacteria and characterized them by biochemical analysis and 16 S sequencing. We have observed a very similar isolates of Arthrobacter (Actinobacteria) degrading 4.1 mM and 4.7 mM of ammonium perchlorate [1] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003300390038003100390037003300340037000000 . In this study, we report PCR based DNA fingerprinting technique to generate the genomic signature of these closely related group of Arthrobacter species. This study also effectively generates unique genomic signature for each of these isolates that has potential for use in molecular monitoring as well as for tracking genomic variation and rearrangements.

Improving dispersion and delamination of graphite in biodegradable starch materials via constructing cation-π interaction: Towards microwave shielding enhancement

Herein, a low-cost, biodegradable, and high-performance microwave shielding graphite/starch material was fabricated via constructing a cation-π interaction between ammonium ions and graphite. The graphite flakes and starch were firstly mixed with distilled water containing ammonium hydroxide to form graphite/starch slurry under an ultrasonic assistant. The cation-π interaction could improve delamination degree and dispersion of graphite in starch matrix. The slurry was first used as a coating material on the surface of wood and paper to develop shielding packages. The effect of coating thickness and coating layers on EM shielding property of the materials was investigated. Second, the composites with a high orientation of graphite were fabricated by compression at high pressures. The electrical conductivity and EM shielding effectiveness(SET) of the materials were greatly enhanced by construction of cation-πinteraction and orientation of graphite. Specifically, the EM SETvalues increased from 56.9 to 66.8 d B for the composites with 50 wt.% graphite and 2.0 mm in thickness by constructing cation-π interaction. The EM SETvalues raised from 17.4 to 66.8 d B via the graphite orientation in the materials with the same components and thickness. The shielding mechanism of the compressed composites with orientation dispersion of graphite was also discussed in comparison to the coating layer with random dispersion of graphite.

Enhanced RuBisCO activity and promoted dicotyledons growth with degradable carbon dots

The ~ 5 nm degradable carbon dots (CDs) were synthesized directly from carbon rod by a one-step electrochemical method at room temperature.The as-prepared CDs can effectively enhance the ribulose bisphosphate carboxylase oxygenase (RuBisCO) activity,and then promote the dicotyledons growth (soybean,tomato,eggplant and so on) and finally increase their yields.Here,we used Arabidopsis thaliana and Trifolium repens L.as model plants to systematically study the beneficial effects of CDs on plant growth.These include:(i) accelerating seed germination;(ii) enlarging root elongation;(iii) increasing metal ions absorption and delivery;(iv) improving enzymes activity;(v) enhancing the carbohydrate content;(vi) degradation into plant hormone analogues and CO2;and finally (vii) enhancing the grain production by about 20%.

In Vivo and In Vitro Degradation Behavior of Magnesium Alloys as Biomaterials

The corrosion behavior of pure Mg,AZ31,and AZ91D were evaluated in various in vitro and in vivo environments to investigate the potential application of these metals as biodegradable implant materials.DC polarization tests and immersion tests were performed in different simulated body solutions,such as distilled（DI） water,simulated body fluid（SBF） and phosphate buffered solution（PBS）.Mg/Mg alloys were also implanted in different places in a mouse for in vivo weight loss and biocompatibility investigations.The in vivo subcutis bio-corrosion rate was lower than the corrosion rate for all of the in vitro simulated corrosive environments.The Mg/Mg alloys were biocompatible based on histology results for the liver,heart,kidney,skin and lung of the mouse during the two months implantation.Optical microscopy and scanning electron microscopy were carried out to investigate the morphology and topography of Mg/Mg alloys after immersion testing and implantation to understand the corrosion mechanisms.