Cryogels are a type of hydrogel material which are fabricated by cryopolymerization at subzero temperature. Due to their unique macroporous structure, shape memory properties and injectability, cryogels have gained significant interest in the fields of tissue engineering for encouraging the repair and regeneration of injured tissues. In this review, the basic concepts relevant to cryogels are introduced, and then the fabrication principle, the process parameters and the unique properties of cryogel are discussed. Next, the latest advances of cryogels as three-dimensional scaffold for various tissue engineering applications are given. Finally, this review summarizes the current limitations of cryogels, and strategies to further improve their properties for tissue engineering. The purpose of this article is to provide a reference guide for the researchers in related fields.
Cryogels ; Porosity ; Tissue Engineering ; Tissue Scaffolds

Objective In the computational fluid dynamics software FLUENT, the independently developed user defined function (UDF) dynamic mesh program is called to achieve the mobile update of grid note based on the wall shear stress (WSS). Then this method is applied to simulate the development process of atherosclerosis (AS). Methods The UDF program by secondary development could extract WSS results of every note on the wall during the computing process, and if the threshold value criterion condition was met, the node would be adjusted to a new position. The mesh regeneration method combining with the spring smoothing and the local remeshing was adopted to control the update of the grid, so as to ensure the grid quality during deformation. Results The UDF program successfully extracted the WSS and arranged the corresponding deformation for the grid. The morphology of local extension in the proximal part and restenosis in the distal end were resulted from the vortex in the rear of the initial stenosis. Those features were similar to the indication of clinical angiography. Conclusions The independently developed UDF program has reached the expected effects, depicting the topography characteristics of AS influenced by WSS. In future researches, more influential factors should be considered in dynamic mesh deformation control to provide numerical references for clinical prognosis and risk evaluation of AS.

OBJECTIVETo comparatively investigate the inorganic composition and crystallographic properties of cortical and cancellous bone via thermal treatment under 700 °C.

METHODSThermogravimetric measurement, infrared spectrometer, X-ray diffraction, chemical analysis and X-ray photo-electron spectrometer were used to test the physical and chemical properties of cortical and cancellous bone at room temperature 250 °C, 450 °C, and 650 °C, respectively.

RESULTSThe process of heat treatment induced an extension in the a-lattice parameter and changes of the c-lattice parameter, and an increase in the crystallinity reflecting lattice rearrangement after release of lattice carbonate and possible lattice water. The mineral content in cortical and cancellous bone was 73.2wt% and 71.5wt%, respectively. For cortical bone, the weight loss was 6.7% at the temperature from 60 °C to 250 °C, 17.4% from 250 °C to 450 °C, and 2.7% from 450 °C to 700 °C. While the weight loss for the cancellous bone was 5.8%, 19.9%, and 2.8 % at each temperature range, the Ca/P ratio of cortical bone was 1.69 which is higher than the 1.67 of stoichiometric HA due to the B-type CO₃²⁻ substitution in apatite lattice. The Ca/P ratio of cancellous bone was lower than 1.67, suggesting the presence of more calcium deficient apatite.

CONCLUSIONThe collagen fibers of cortical bone were arrayed more orderly than those of cancellous bone, while their mineralized fibers ollkded similar. The minerals in both cortical and cancellous bone are composed of poorly crystallized nano-size apatite crystals with lattice carbonate and possible lattice water. The process of heat treatment induces a change of the lattice parameter, resulting in lattice rearrangement after the release of lattice carbonate and lattice water and causing an increase in crystal size and crystallinity. This finding is helpful for future biomaterial design, preparation and application.

Animals ; Bone Density ; physiology ; Bone and Bones ; chemistry ; ultrastructure ; Crystallography ; Spectrophotometry, Infrared ; Swine

Early life nutritional environment is not only associated with the growth and development of children, but also affects the health of adults. Numerous epidemiological and animal studies suggest that early nutritional programming is an important physiological and pathological mechanism. DNA methylation is one of the important mechanisms of nutritional programming, which is catalyzed by DNA methyltransferase, a specific base of DNA covalently binds to a methyl group, to regulate gene expression. In this review, we summarize the role of DNA methylation in the "abnormal developmental planning" of key metabolic organs caused by excessive nutrition in early life, resulting in long-term obesity and metabolic disorders in the offspring, and explore the clinical significance of regulating DNA methylation levels through dietary interventions to prevent or reverse the occurrence of metabolic disorders in the early stage in a "deprogramming" manner.
Humans ; Animals ; Female ; DNA Methylation ; Epigenesis, Genetic ; Clinical Relevance ; Maternal Nutritional Physiological Phenomena ; Metabolic Diseases

Ion concentration polarization (ICP) is an electrical transport phenomenon that occurs at the micro-nano interface under the action of an applied electric field, and the ICP phenomenon can be used to enrich charged particles with high efficiency. The microfluidic chip has the advantages of high precision, high efficiency, easy integration and miniaturization in biochemical analysis, which provides a new solution and technical way for biochemical analysis. In response to the demand for the detection of trace charged target analytes in sample solution, the advantages of high enrichment multiplicity, convenient operation and easy integration of ICP are utilized to provide an effective way for microfluidic biochemical detection. The combination of ICP phenomenon and microfluidic analysis technology has been widely used in the fields of pre-enrichment of charged particles, separation of targets, and detection of target analytes in biochemical analysis. In this paper, the principle of ICP and the microfluidic ICP chip are briefly introduced. Under the action of external electric field, the co-ions pass through the ion-selective nanochannel, the counterions are rejected at the boundary of nanochannel to form a depletion zone, and the charged samples will be enriched at the boundary of the depletion zone. Then the preparation techniques and methods of ICP chips are summarized. Among them, the design of microfluidic channel structure and the preparation and design of nanostructures are emphasized. The basic single-channel structure is analyzed, and the parallel-channel structure as well as the integrated multi-functional microfluidic ICP chip are sorted out and summarized. The preparation methods of nanostructures in ICP chips and their respective advantages and disadvantages are listed, and it is summarized that the current mainstream means are the embedding method and the self-assembly method, and attention is paid to the design of nanostructures preparation methods by both of them. In addition, this paper also discusses how to optimize the enrichment efficiency of ICP chip, through the introduction of multi-field coupling, valve control and other means to achieve the optimization of the enrichment efficiency of target substances. Meanwhile, this paper provides a classified overview of the progress of application of ICP chips in biochemical analysis and detection. ICP chips have been widely used in the research and development of biosensors, which can be used for the enrichment and separation of a variety of analytes including small molecules, nucleic acids, proteins, and cells, etc. By changing the design of microfluidic structures, integrating detection methods and modifying specific antibodies, ICP chips have shown great potential in the fields of rapid enrichment and pre-processing of targets, separation of targets and highly sensitive detection. Finally, it is pointed out that ICP chips are facing challenges in improving enrichment efficiency and selectivity, and solving the problems of fluid control, mixing and transport to match the biological properties of target assay, and that microfluidic ICP chips have been continuously promoting the development of ICP chips through the improvement of materials, chip design and integration of multifunctional units, opening up new possibilities in the field of biochemical analysis methods and applications. It can be seen that microfluidic ICP chips have the advantages of low sample flow rate, good separation and enrichment, high detection efficiency, and easy integration and miniaturization, which have shown good research significance and practical prospects in the field of biochemical detection.

Adult ; China ; Dimethoate/analogs & derivatives* ; Farmers/statistics & numerical data* ; Female ; Humans ; Male ; Middle Aged ; Occupational Exposure ; Pesticides/adverse effects* ; Polymorphism, Single Nucleotide ; Telomerase/genetics* ; Telomere/physiology*

OBJECTIVE To analyze the chemical constituents and components absorbed into plasma of the extract of Ardisia crenata and to elucidate its possible pharmacodynamic material basis. METHODS Overall， 12 rats were randomly assigned to the blank group （n＝6） and A. crenata group （n＝6） by the paired comparison method. The drug was administered once daily in the morning and afternoon for three days. Serum samples were prepared from serum after redosing on 4th day. The UPLC-QE-HF-MS/ MS was used to analyze and identify the chemical constituents in A. crenata extract and serum samples. Compound Discoverer 3.0 was employed for retention time correction， peak identification， and peak extraction. According to the secondary mass spectrometry information， the Thermo mzCloud online and Thermo mzVault local databases， referring to the relevant literature and control quality spectrum information were used to preliminarily identify the chemical constituents and components absorbed into plasma of A. crenata. RESULTS A total of 34 compounds were identified from the extract of A. crenata， mainly coumarins， flavonoids， organic acids， amino acids， including bergenin， quercetin， gallic acid， L-pyroglutamic acid， etc. Besides， 5 components absorbed into plasma were identified from serum samples: L-pyroglutamic acid， syringic acid， bergenin， cinnabar root saponin A， and mycophenolic acid. CONCLUSIONS L-pyroglutamic acid， syringic acid， bergenin， cinnabar root saponin A， and mycophenolic acid may act as the pharmacodynamic material basis of A. crenata.