The microstructure of porous scaffolds plays a vital role in bone regeneration, but its optimal shape is still unclear. In this study, four kinds of porous titanium alloy scaffolds with similar ...porosities (65%) and pore sizes (650 μm) and different structures were prepared by selective laser melting. Four scaffolds were implanted into the distal femur of rabbits to evaluate bone tissue growth in vivo. Micro-CT and hard tissue section analyses were performed 6 and 12 weeks after the operation to reveal the bone growth of the porous scaffold. The results show that diamond lattice unit (DIA) bone growth is the best of the four topological scaffolds. Through computational fluid dynamics (CFD) analysis, the permeability, velocity and flow trajectory inside the scaffold structure were calculated. The internal fluid velocity difference of the DIA structure is the smallest, and the trajectory of fluid flow inside the scaffold is the longest, which is beneficial for blood vessel growth, nutrient transport and bone formation. In this study, the mechanism of bone growth in different structures was revealed by in vivo experiments combined with CFD, providing a new theoretical basis for the design of bone scaffolds in the future.
A significant requirement for a bone implant is to let bone cells grow better. However, how to increase the cellular activity of the scaffold at a certain elastic modulus remains unclear. Here, we ...developed a method to derive the relationship between design parameters, porosity, and mechanical properties of uniform structures for pore functionally graded scaffolds (PFGS) design. PFGS is a combination of different uniform structures by matching design parameters. Ti6Al4V PFGS and uniform structures with sizes of 10 × 10 × 12 mm were designed and fabricated via selective laser melting (SLM). The mechanical properties and cell proliferation of these structures were investigated. Results indicated that the mathematical model of elastic modulus, yield strength and porosity can accurately predict the mechanical properties of structures. For PFGS, cell proliferation rate from day 4 to day 7 was 140%, while for the uniform structures were only 90%. The results demonstrated that PFGS is more suitable for bone tissue implantation.
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•Mathematical models were developed to calculate elastic modulus, yield strength and porosity of uniform structures.•A novel approach for the design of pore functionally graded scaffolds suitable for bone engineering application is proposed.•The strain-stress curves of pore functionally graded scaffold are as same as that of the uniform structures.•Cell proliferation rate is significantly higher for pore functionally graded scaffold, in comparison to the uniform scaffold.
The aim of this research was to determine the effect of development and UV‐B on flavonols and the regulation of gene activity in Vitis vinifera L. var. Sauvignon blanc grapes. Particular emphasis was ...placed on gene activity associated with the low and high fluence UV‐B responses. Flavonols, particularly quercetin and kaempferol glycosides, increased substantially upon fruit exposure due to UV‐B, with spatial analysis locating the changes to the berry skin. Of five VvFLS genes in grapes, two (VvFLS4 and 5) were found to be transcriptionally active, with VvFLS4 also being responsive to UV‐B but VvFLS5 was not. Of the transcription factors known to regulate FLS (VvMYB12, VvMYCA1 and VvWDRs), only VvMYB12 was found to be responsive to UV‐B. A number of candidate genes associated with the low and high UV‐B fluence responses were also studied (VvUVR8, VvHY5, VvCOP1 and VvCHS; PR genes and VvMAPK3; respectively). The genes associated with the low fluence response exhibited transcriptional regulation in line with reports from other species, while the PR genes and VvMAPK3 only appeared to be responsive in a high UV‐B fluence environment. Together, these data supports the view flavonol biosynthesis in grape is stimulated predominantly through the low fluence UV‐B response pathway.
This research investigates the effect of development and UV‐B on flavonols and the regulation of gene activity in Vitis vinifera L. var. Sauvignon blanc grapes. Results suggest flavonol biosynthesis and gene activity are stimulated by UV‐B and the low fluence UV‐B pathway is a major determinant of this response. There is also a strong influence of development on gene expression. This is the first research to analyse signal transduction associated with the recently discovered UV‐B photoreceptor UVR8 and makes a substantial contribution to understanding UV‐B responses in an important commercial species.
Purely organic electroluminescent materials, such as thermally activated delayed fluorescent (TADF) and triplet–triplet annihilation (TTA) materials, basically harness triplet excitons from the ...lowest triplet excited state (T1) to realize high efficiency. Here, a fluorescent material that can convert triplet excitons into singlet excitons from the high‐lying excited state (T2), referred to here as a “hot exciton” path, is reported. The energy levels of this compound are determined from the sensitization and nanosecond transient absorption spectroscopy measurements, i.e., small splitting energy between S1 and T2 and rather large T2–T1 energy gap, which are expected to impede the internal conversion (IC) from T2 to T1 and facilitate the reverse intersystem crossing from the high‐lying triplet state (hRISC). Through sensitizing the T2 state with ketones, the existence of the hRISC process with an ns‐scale delayed lifetime is confirmed. Benefiting from this fast triplet–singlet conversion, the nondoped device based on this “hot exciton” material reaches a maximum external quantum efficiency exceeding 10%, with a small efficiency roll‐off and CIE coordinates of (0.15, 0.13). These results reveal that the “hot exciton” path is a promising way to exploit high efficient, stable fluorescent emitters, especially for the pure‐blue and deep‐blue fluorescent organic light‐emitting devices.
A pure‐blue fluorescent organic light‐emitting device (OLED) based on phenanthroimidazole−anthracene derivative obtains a maximum external quantum efficiency of 10.5% with excellent stability. Experimental investigations reveal that the high efficiency is attributed to triplet exciton harvesting by reverse intersystem crossing from the high‐lying triplet state. The results demonstrates that “hot exciton” channels represent a promising way to construct high‐performance fluorescent OLEDs.
The living environment of bone cells is a complex curved one. And based on the modeling method of triply periodic minimal surfaces (TPMS) can be used to design a variety of complex surface ...structures, so it has been more and more widely studied and applied. In this paper, the main research object is the Primitive structure of TPMS. As an artificial bone scaffold structure, it must possess good mechanical properties, permeability, and is conducive to cell adhesion and proliferation. In this study, several groups of Ti6Al4V Primitive models are designed and fabricated by selective laser melting (SLM). The mechanical properties of scaffold are evaluated by mechanical compression test. The morphology of the scaffold model is characterized. The permeability of the scaffold was predicted and evaluated by computational fluid dynamics (CFD) analyses. Finally, the evaluation of the effects of Ti6A14V scaffold on cell growth is conducted by cytotoxicity test. The results show that the mechanical properties and permeability of the designed Primitive surface scaffold are pretty good as bone tissue replacement. Among them, the Psy scaffold with pore size and porosity varying along the axisymmetric gradient has significant research and application potential in the field of artificial bone scaffold.
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•The relationship between pore size and porosity of Primitive surface structures is determined.•The three groups of Ti6Al4V Primitive scaffold models all meet the requirements of mechanical properties of bone scaffolds.•CFD analysis showed that the Primitive surface structure was beneficial to the adsorption of bone cells and nutrients.•The structure of Psy with symmetrical gradient variation of aperture proved to have better permeability.
Organic light-emitting diodes （OLEDs） have been extensively studied since the first efficient device based on small molecular luminescent materials was reported by Tang. Organic electroluminescent ...material, one of the centerpieces of OLEDs, has been the focus of studies by many material scientists. To obtain high luminosity and to keep material costs low, a few remarkable design concepts have been developed. Aggregation-induced emission （AIE） materials were invented to overcome the common fluorescence-quenching problem, and cross-dipole stacking of fluorescent molecules was shown to be an effective method to get high solid-state luminescence. To exceed the limit of internal quantum efficiency of conventional fluorescent materials, phosphorescent materials were successfully applied in highly efficient electroluminescent devices. Most recently, delayed flu- orescent materials via reverse-intersystem crossing （RISC） from triplet to singlet and the ＂hot exciton＂ materials based on hy- bridized local and charge-transfer （HLCT） states were developed to he a new generation of low-cost luminescent materials as efficient as phosphorescent materials. In terms of the device-fabrication process, solution-processible small molecular lumi- nescent materials possess the advantages of high purity （vs. polymers） and low procession cost （vs. vacuum deposition）, which are garnering them increasing attention. Herein, we review the progress of the development of small-molecule luminescent materials with different design concepts and features, and also briefly examine future development tendencies of luminescent materials.
Gold nanoparticles (AuNPs), as a kind of inorganic nanoparticle, have been gradually recognized as one of the most promising nanomaterials, which is attributed to their unique optical, electronic, ...sensing and biochemical characteristics. Due to such unique characteristics, AuNPs have been widely applied in biomedical fields such as diagnosis, biosensing and drug delivery. Except for their use in cancer treatment alone with their photothermal ablation of solid tumours, when used with anticancer drugs, AuNPs can exert a dual role in treating cancer. With the advantages of protecting drugs from degradation and leakage in the physiological environment, tuneable modification in size, surface and shape, and biocompatibility, AuNPs can be used as promising drug carriers in anticancer drug design. However, there are still many aspects that need to be improved during the usage of drug carriers in pharmacology including the following aspects: prolongation in the plasma, enhancement in targeting accumulation, improvement in cellular uptake and the control of intracellular release. AuNPs are important drug carriers.
Conventionally, the electromechanical system requires the installation of auxiliary displacement sensors and only the amount on the drive part and motion end, which increases volume, cost, and ...measurement error in the system. This paper presents an integrated measurement method with a sensing head, which takes the equal division characteristics of mechanical structures as part of the sensor, thus, the so-called self-sensing system. Moreover, the displacement is measured by counting the time pulses. The sensing head is integrated with the entire electromechanical system, including the driving, transmitting, and moving parts. Thus, the integration of the sensing part is greatly improved. Taking the rotary table as a special example, and the sensing head embedded into each part of the system, displacement information is obtained by the common processing system and fused by the adaptive weighted average method. The results of the experiment show that the fusion precision of each component is higher than only the motor position information as the feedback. The proposed method is a practical self-sensing technology with significant volume reduction and intelligent control benefits in the industry, especially suitable for extremely small and narrow spaces.
•An optimization-based framework for molecular and mixture product design is developed.•An MINLP model for CAMD is established to design different kinds of chemical products simultaneously.•A ...versatile tool for chemical product design and evaluation “OptCAMD” is developed and integrated in ProCAPD.•Case studies highlighting different aspects of OptCAMD involving the design of various types of chemical products are presented.
Chemical product design determines the structure and constitution of products that satisfies all desired properties and functions. Molecular products are usually employed as the main active ingredient, or manipulated to obtain a specific function for chemical-based products, while mixtures are one of the most widely used chemical products. Therefore, the design of molecular and mixture products is the foundation of all chemical product design problems. In this paper, the development of an optimization-based framework for molecular and mixture product design is presented. The design work-flow consists of three steps involving preliminary design, CAMD (Computer Aided Molecular-Mixture Design), as well as product evaluation and verification. In the preliminary design step, the product attributes are collected and converted into a set of desired physico-chemical properties with associated targets to formulate the CAMD problem. In the CAMD step, an optimization-based mathematical programming model is established and solved to generate feasible molecules and/or mixtures together with optimal product candidates. In the product evaluation and verification step, final selection of the optimal chemical product is made based on evaluation of in-use product performance attributes and additional properties not included in the CAMD step. The three steps have been implemented within a molecular-mixture design toolbox called “OptCAMD”, which is integrated in ProCAPD, a versatile tool for chemical product design and evaluation. Case studies highlighting different aspects of OptCAMD involving the design of various types of chemical products are presented.
Chloroplast development and chlorophyll metabolism have been well described in model plants but not in perennial woody crops. Of particular interest is the interplay between light and hormones under ...shade conditions. We report that the shade induced accumulation of chlorophylls in
cv. Shuchazao leaves is at least as a result of (a) positive changes in chloroplast development and (b) light/hormonal regulation of genes and transcription factors involved in the chlorophyll biosynthesis pathway. Under shade conditions, leaves developed an abundance of enlarged chloroplasts encapsulating more prominent thylakoid membranes. Four major metabolites in the chlorophyll biosynthesis pathway namely Chl
, Chl
, DPP, and Mg-Proto IX increased under shade conditions while PBG decreased significantly. Significant changes were found at the transcription level of regulators of chloroplast biogenesis (
and
), the structural genes in the chlorophyll biosynthesis pathway (
,
,
, and
) and potential components involved in light signaling (
,
,
, and
). Two central signal integrators (
and
between the nucleus and chloroplast showed clear responses to shade, suggesting a crucial role of light in regulating chloroplast development in tea leaves. Concurrent with the changes in gene expression, the concentrations of endogenous phytohormones (auxin, cytokinin, and gibberellins) increased significantly in the later stages of shade conditions. Two key integrators involved in the hormone signal pathways, EIN3 and EBF1/2, increased under shade conditions suggesting that shade induced changes to hormone levels may play some role in modulating chlorophyll biosynthesis in the tea leaves. Overall, this data suggests that the light and hormone influence over chloroplast development and chlorophyll biosynthesis in
is similar to that of
. This study provides new insights into the molecular mechanisms that regulate chlorophyll biosynthesis in response to light and hormones in a commercially important woody plant such as
, which may facilitate the breeding of high-chlorophyll tea cultivars for the improvement of sensory features of the green tea product.
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