SC9-4和棕榈油的比较分析研究

SC_9-4是以植物油为原料研制成功的一种高速冷轧工艺润滑油。经武钢高速冷轧机轧制性能鉴定,它的高速轧制性能优于棕榈油。我们使用高效液相色谱比较分析鉴定了SC_9-4和棕榈油的甘油三酯组成。分析结果:SC_9-4:的主要甘油三酯是POP(42.8％)和PPP(14.6％),而棕榈油的主要甘油三酯是POP(31.3％)、POO(20.1％)、PLP(12.2％)和PLO(11.6％)。我们初步探讨甘油三酯组成与轧制性能关系认为,SC_9-4的高速轧制性能优于棕榈油,可能是和SC_9-4含PPP、PPS和PSS的含量(18.8％)高于棕榈油(9.9％)有关。     

Numerical simulation of thermal bone necrosis during cementation of femoral prostheses

The implant of a femoral prosthesis is a critical process because of the relatively high temperature values reached at the bone/cement interface during the cementation of the infibulum. In fact, the cement is actually a polymer that polymerizes in situ generating heat. Moreover, the conversion of monomer into polymer is never 100%; this is dangerous because of the toxicity of the monomer. In this paper, we present a 3-D axisymmetric mathematical model capable of taking into account both the geometry of the implant and the chemical/physical properties of the cement. This model, together with its numerical simulation, thus represents a useful tool to set up the optimal conditions for the new materials developed in this orthopaedic field. The real complex geometry is assumed to be a bone/cement/metallic system having cylindrical symmetry, thus allowing the model to be reduced to two space variables. The cementation process is described by the Fourier heat equation coupled with a suitable polymerization kinetics. The numerical approximation is accomplished by semi-implicit finite differences in time and finite elements in space with numerical quadrature. The full discrete scheme amounts to solve linear positive definite symmetric systems preceded by an elementwise algebraic computation. We present various numerical simulations which confirm some critical aspects of this orthopaedic fixing technique such as thermal bone necrosis and the presence of unreacted residual monomer.This work was partially supported by MURST (Fondi per la Ricerca Scientifica 40%) and CNR (IAN, Contract 880032601, and Progetto Finalizzato Sistemi Informatici e Calcolo Parallelo, Sottoprogetto Calcolo Scientifico per Grandi Sistemi) of Italy     

In vitro cultivation methods for coccidian parasite research

The subclass Coccidia comprises a large group of protozoan parasites, including important pathogens of humans and animals such as Toxoplasma gondii, Neospora caninum, Eimeria spp., and Cystoisospora spp. Their life cycle includes a switch from asexual to sexual stages and is often restricted to a single host species. Current research on coccidian parasites focuses on cell biology and the underlying mechanisms of protein expression and trafficking in different life stages, host cell invasion and host-parasite interactions. Furthermore, novel anticoccidial drug targets are evaluated. Given the variety of research questions and the requirement to reduce and replace animal experimentation, in vitro cultivation of Coccidia needs to be further developed and refined to meet these requirements. For these purposes, established culture systems are constantly improved. In addition, new in vitro culture systems lately gained considerable importance in research on Coccidia. Well established and optimized in vitro cultures of monolayer cells can support the viability and development of parasite stages and even allow completion of the life cycle in vitro, as shown for Cystoisospora suis and Eimeria tenella. Furthermore, new three-dimensional cell culture models are used for propagation of Cryptosporidium spp. (close relatives of the coccidians), and the infection of three-dimensional organoids with T. gondii also gained popularity as the interaction between the parasite and host tissue can be studied in more detail. The latest advances in three-dimensional culture systems are organ-on-a-chip models, that to date have only been tested for T. gondii but promise to accelerate research in other coccidians. Lastly, the completion of the life cycle of C. suis and Cryptosporidium parvum was reported to continue in a host cell-free environment following the first occurrence of asexual stages. Such axenic cultures are becoming increasingly available and open new avenues for research on parasite life cycle stages and novel intervention strategies.     

Improved design of peptides exhibiting angiogenic activities for clinical applications

Vascularization is one of the key steps for engraftment in regenerative medicine. Previously one of the authors had discovered peptides exhibiting significant angiogenic activities designated AGP and elucidated the active core. For neovascularization basic fibroblast growth factor is used although permeation can be envisaged. The original AGPs did not suffer from this although their half-life times are short because of decomposition by endogenous enzymes. Several new AGP-libraries have been constructed and their enzymatic resistance has been investigated by the use of human umbilical vein endothelial cells to find candidates for clinical applications.     

Restorative and regenerative: Exploring the concepts in the circular economy

The most recognized definition of the circular economy is that it is a restorative and regenerative economy. Despite the wide use and importance attributed to the concepts of “restoration” and “regeneration,” they are rarely defined or explained in the circular economy literature. In this context, this study critically examines the two terms, while providing guidance on their future utilization and development. Specifically, the study investigates the origin of the concepts, their adoption in frameworks that anticipated the idea of the circular economy, and their connotations in the circular economy literature. The examination supports the need for clear and distinct definitions, combined with precision in usage. From a review of the literature, restoration is a better‐defined concept than regeneration, although it needs conceptual re‐enforcement relative to the biological/ecological aspects of the circular economy. This study suggests looking in the direction of restoration ecology, a well‐established branch of ecological research. Conversely, regeneration is a symbolic/evocative term with little practical application in the context of circular systems except in the case of certain agricultural practices. Until new conceptual developments intervene, regeneration does not seem to be applicable to the economy as a whole and because of this, might be abandoned as a guiding principle of the circular economy. Unlike regeneration, restoration can be considered a core principle because it has widespread application and can be a point of reference for circular applications. This does not preclude the possibility that other concepts may be needed to augment restoration.     

Sustainable intensification of crop residue exploitation for bioenergy: Opportunities and challenges

Crop residue exploitation for bioenergy can play an important role in climate change mitigation without jeopardizing food security, but it may be constrained by impacts on soil organic carbon (SOC) stocks, and market, logistic and conversion challenges. We explore opportunities to increase bioenergy potentials from residues while reducing environmental impacts, in line with sustainable intensification. Using the case study of North Rhine‐Westphalia in Germany, we employ a spatiotemporally explicit approach combined with stakeholder interviews. First, the interviews identify agronomic and environmental impacts due to the potential reduction in SOC as the most critical challenge associated with enhanced crop residue exploitation. Market and technological challenges and competition with other residue uses are also identified as significant barriers. Second, with the use of agroecosystem modelling and estimations of bioenergy potentials and greenhouse gas emissions till mid‐century, we evaluate the ability of agricultural management to tackle the identified agronomic and environmental challenges. Integrated site‐specific management based on (a) humus balancing, (b) optimized fertilization and (c) winter soil cover performs better than our reference scenario with respect to all investigated variables. At the regional level, we estimate (a) a 5% increase in technical residue potentials and displaced emissions from substituting fossil fuels by bioethanol, (b) an 8% decrease in SOC losses and associated emissions, (c) an 18% decrease in nitrous oxide emissions, (d) a 37% decrease in mineral fertilizer requirements and emissions from their production and (e) a 16% decrease in nitrate leaching. Results are spatially variable and, despite improvements induced by management, limited amounts of crop residues are exploitable for bioenergy in areas prone to SOC decline. In order to sustainably intensify crop residue exploitation for bioenergy and reconcile climate change mitigation with other sustainability objectives, such as those on soil and water quality, residue management needs to be designed in an integrated and site‐specific manner.     

A biotechnology‐based male‐sterility system for hybrid seed production in tomato

Incorporating male sterility into hybrid seed production reduces its cost and ensures high varietal purity. Despite these advantages, male‐sterile lines have not been widely used to produce tomato (Solanum lycopersicum) hybrid seeds. We describe the development of a biotechnology‐based breeding platform that utilized genic male sterility to produce hybrid seeds. In this platform, we generated a novel male‐sterile tomato line by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR‐associated protein 9 (Cas9)‐mediated mutagenesis of a stamen‐specific gene SlSTR1 and devised a transgenic maintainer by transforming male‐sterile plants with a fertility‐restoration gene linked to a seedling‐colour gene. Offspring of crosses between a hemizygous maintainer and the homozygous male‐sterile plant segregated into 50% non‐transgenic male‐sterile plants and 50% male‐fertile maintainer plants, which could be easily distinguished by seedling colour. This system has great practical potential for hybrid seed breeding and production as it overcomes the problems intrinsic to other male‐sterility systems and can be easily adapted for a range of tomato cultivars and diverse vegetable crops.     

Flexible chromosome painting based on multiplex PCR of oligonucleotides and its application for comparative chromosome analyses in Cucumis

Chromosome painting is a powerful technique for chromosome and genome studies. We developed a flexible chromosome painting technique based on multiplex PCR of a synthetic oligonucleotide (oligo) library in cucumber (Cucumis sativus L., 2n = 14). Each oligo in the library was associated with a universal as well as nested specific primers for amplification, which allow the generation of different probes from the same oligo library. We were also able to generate double‐stranded labelled oligos, which produced much stronger signals than single‐stranded labelled oligos, by amplification using fluorophore‐conjugated primer pairs. Oligos covering cucumber chromosome 1 (Chr1) and chromosome 4 (Chr4) consisting of eight segments were synthesized in one library. Different oligo probes generated from the library painted the corresponding chromosomes/segments unambiguously, especially on pachytene chromosomes. This technique was then applied to study the homoeologous relationships among cucumber, C. hystrix and C. melo chromosomes based on cross‐species chromosome painting using Chr4 probes. We demonstrated that the probe was feasible to detect interspecies chromosome homoeologous relationships and chromosomal rearrangement events. Based on its advantages and great convenience, we anticipate that this flexible oligo‐painting technique has great potential for the studies of the structure, organization, and evolution of chromosomes in any species with a sequenced genome.