Ecosystem Carbon Stock Loss after Land Use Change in Subtropical Forests in China

Converting secondary natural forests (SFs) to Chinese fir plantations (CFPs) represents one of the most important (8.9 million ha) land use changes in subtropical China. This study estimated both biomass and soil C stocks in a SF and a CFP that was converted from a SF, to quantify the effects of land use change on ecosystem C stock. After the forest conversion, biomass C in the CFP (73 Mg¨ ha´1 ) was significantly lower than that of the SF (114 Mg¨ ha´1 ). Soil organic C content and stock decreased with increasing soil depth, and the soil C stock in the 0–10 cm layer accounted for more than one third of the total soil C stock over 0–50 cm, emphasizing the importance of management of the top soil to reduce the soil C loss. Total ecosystem C stock of the SF and the CFP was 318 and 200 Mg¨ ha´1 , respectively, 64% of which was soil C for both stands (205 Mg¨ ha´1 for the SF and 127 Mg¨ ha´1 for the CFP). This indicates that land use change from the SF to the CFP significantly decreased ecosystem C stock and highlights the importance of managing soil C

Ecosystem Carbon Stock Loss after Land Use Change in Subtropical Forests in China

Converting secondary natural forests (SFs) to Chinese fir plantations (CFPs) represents one of the most important (8.9 million ha) land use changes in subtropical China. This study estimated both biomass and soil C stocks in a SF and a CFP that was converted from a SF, to quantify the effects of land use change on ecosystem C stock. After the forest conversion, biomass C in the CFP (73 Mg¨ ha´1 ) was significantly lower than that of the SF (114 Mg¨ ha´1 ). Soil organic C content and stock decreased with increasing soil depth, and the soil C stock in the 0–10 cm layer accounted for more than one third of the total soil C stock over 0–50 cm, emphasizing the importance of management of the top soil to reduce the soil C loss. Total ecosystem C stock of the SF and the CFP was 318 and 200 Mg¨ ha´1 , respectively, 64% of which was soil C for both stands (205 Mg¨ ha´1 for the SF and 127 Mg¨ ha´1 for the CFP). This indicates that land use change from the SF to the CFP significantly decreased ecosystem C stock and highlights the importance of managing soil C

Macromolecularly crowded in vitro microenvironments accelerate the production of extracellular matrix-rich supramolecular assemblies

Therapeutic strategies based on the principles of tissue engineering by self-assembly put forward the notion that functional regeneration can be achieved by utilising the inherent capacity of cells to create highly sophisticated supramolecular assemblies. However, in dilute ex-vivo microenvironments, prolonged culture time is required to develop an extracellular matrix-rich implantable device. Herein, we assessed the influence of macromolecular crowding, a biophysical phenomenon that regulates intra- and extra-cellular activities in multicellular organisms, in human corneal fibroblast culture. In the presence of macromolecules, abundant extracellular matrix deposition was evidenced as fast as 48 h in culture, even at low serum concentration. Temperature responsive copolymers allowed the detachment of dense and cohesive supramolecularly assembled living substitutes within 6 days in culture. Morphological, histological, gene and protein analysis assays demonstrated maintenance of tissue-specific function. Macromolecular crowding opens new avenues for a more rational design in engineering of clinically relevant tissue modules in vitro

Development of Simplified NIPAm-based Thermoresponsive Films for Cell Preservation, Expansion and Differentiation

Traditional cell recovery methodologies cleave cell-to-cell junctions and thus the recovery of an intact cell sheet for use in tissue engineering is rendered impossible. Additionally, these traditional cell detachment techniques can be damaging to cell surface receptors, which in turn can impair subsequent cell function. Thermoresponsive polymer film mediated cell growth and recovery, has become a popular way to recover undamaged cells, with cell to cell junctions and basally deposited ECM maintained. These cell sheets can be then used for tissue engineering purposes or tissue damage repair. Thermoresponsive polymer has a lower critical solution temperature (LCST) in aqueous solution, which phenomenon has been exploited in temperature controlled cell harvesting. It has been shown that variety of thermoresponsive surfaces are generally conducive to reasonable cell growth. Okano et al. have grafted pNIPAm onto tissue culture plastic using electron beam polymerisation to yield an ultra-thin layer of pNIPAm. Maria E Nash has demonstrated that thermoresponsive films deposited using spin coating method were able to yield cell culture delivery substrates. This issue has been focused on further to simplify the preparation techniques for fabricating thermoresponsive films with a view to cell preservation. To this end, thermoresponsive platforms were deposited using the solvent cast method to yield thin, uniform, reproducible films. Solvent casting is a basic, cheap and effective method for fabricating films in the micrometre range of thickness. It was first reported as a method to deposit a thermoresponsive film for cell culture in 1990. For comparison purposes films were prepared using solvent cast method and the spin coating method. Two types of NIPAm-based thermoresponsive polymers were used in this research; the first employed commercially sourced pNIPAm, the second a NIPAm-co-NtBAm copolymer. The advantages of using a commercially sourced polymer system paired with the operationally simple solvent cast/spin coating technique for cell sheet regeneration are that films prepared in this manner can be produced with minimal training and expense and the use of a commercially sourced product avoids the need for complex polymerisation processes. The NIPAm-co-NtBAm copolymer was selected for similar applications, it showed better cell compatibility and had a LCST lower than room temperature, which makes the biomaterial much easier and flexible for routine applications. The deposited films were characterised using a variety of analytical techniques before biological assessment. Studies have shown that there is a correlation between the thickness of the deposited pNIPAm films and successful cell adhesion and proliferation; therefore it was imperative that this parameter could be assessed. Successful cell adhesion onto a biomaterial surface is dependent on a number of physiochemical characteristics such as surface wettability, roughness and composition, therefore where a discernible difference in cell growth was observed between films of different thicknesses or deposited by different means; comparative assessments of such characteristics were made. Investigations into films prepared from commercially sourced pNIPAm show that it is the thickness determining factor for successful cell adhesion, thinner films supported more cell adhesion. Human mesenchymal stem cell and macrophage-like transformed murine cell line RAW264.7 grew on thinner solvent cast films better than that on their thicker counterparts. Films prepared from the NIPAm based thermoresponsive polymer via spin coating and solvent cast successfully hosted a wide variety of cells and cell lines to confluence and cell detachment was achieved through temperature modulation. Optimisation of the NIPAm based thermoresponsive films for cell adhesion, proliferation and differentiation allowed for the refinement of crucial parameters to thermoresponsive modifications

Analysis of the Icing Accretion Performance of Conductors and Its Normalized Characterization Method of Icing Degree for Various Ice Types in Natural Environments

Icing degree in the severe icing regions for years is an important factor considered in the anti-icing design of transmission lines. However, there is currently no normalized characterization method for the icing degree of transmission lines, which can be used to record the severity of icing at icing areas over the years and guide the design of transmission lines. This study analyzes collision efficiency of water droplets with various diameters of conductors and investigates the ice accretion law of transmission lines with various diameters under four natural ice types. Therefore, the normalized method of standard ice thickness instead of various ice morphologies is creatively used to characterize icing degree of transmission lines and a lot of field tests which have been done at six natural ice observation stations have verified the effective of the method. The results have shown that: The diameters of conductor and the droplet significantly affect collision efficiency; the relation of standard ice thickness with diameter of conductors for four typical ice types complied with the law of power function. The results can provide important references for the design and external insulation selection of transmission lines in ice region

Macromolecularly crowded in vitro microenvironments accelerate the production of extracellular matrix-rich supramolecular assemblies

Therapeutic strategies based on the principles of tissue engineering by self-assembly put forward the notion that functional regeneration can be achieved by utilising the inherent capacity of cells to create highly sophisticated supramolecular assemblies. However, in dilute ex vivo microenvironments, prolonged culture time is required to develop an extracellular matrix-rich implantable device. Herein, we assessed the influence of macromolecular crowding, a biophysical phenomenon that regulates intra- and extra-cellular activities in multicellular organisms, in human corneal fibroblast culture. In the presence of macromolecules, abundant extracellular matrix deposition was evidenced as fast as 48 h in culture, even at low serum concentration. Temperature responsive copolymers allowed the detachment of dense and cohesive supramolecularly assembled living substitutes within 6 days in culture. Morphological, histological, gene and protein analysis assays demonstrated maintenance of tissue-specific function. Macromolecular crowding opens new avenues for a more rational design in engineering of clinically relevant tissue modules in vitroHealth Research BoardScience Foundation IrelandCollege of Engineering & Informatics, National University of Ireland, Galway, Postgraduate College Fellowshi

Ultrastable and highly efficient CsPbBr3 composites achieved by dual‐matrix encapsulation for display devices

Abstract Perovskite nanocrystals (NCs) with high stabilities and excellent optical performances are crucial for display applications. However, to date, perovskite emitters with both high photoluminescence (PL) quantum yield (PLQY) and high stabilities under harsh synergistic humidity–heat–light aging conditions have not been reported. The promising high‐temperature solid‐state sintering with single oxide matrices cannot ensure high PLQY and synergistic aging stabilities of perovskites. Herein, both the PLQY and overall (thermal, moisture, and photo) stabilities of all‐inorganic perovskite (CsPbBr3) NCs are improved by dual‐matrix encapsulation, which is accomplished by in situ crystallization of CsPbBr3@Cs4PbBr6 nanocomposites in silica molecular sieve (MS) templates via advanced solid‐state synthesis a using precisely controlled molar ratio of precursor components and cooling rates. The Cs4PbBr6 matrix effectively passivates the surfaces of CsPbBr3 NCs, and the MS matrix insulates CsPbBr3@Cs4PbBr6 from the external environment. The resulting CsPbBr3@Cs4PbBr6/MS composites exhibit the highest PLQY (>90%) among those of the solid‐state perovskite NCs and significant stabilities against water, heat, and blue light irradiation, maintaining more than 80% of their initial PL intensities after being aged for 1000 h under synergistic high‐humidity (85%), high‐temperature (85°C), and strong blue light irradiation (350 mW cm−2) conditions. To the best of our knowledge, these CsPbBr3@Cs4PbBr6/MS composites represent the most stable perovskite emitters under synergistic humidity–heat–light aging conditions. The liquid crystal display backlight module fabricated using these stable composites demonstrates a wide color gamut of 131% of the National Television Standards Committee standard. We speculate that this dual‐matrix encapsulation can be used for industrial mass production