A variable mineralization time and solution concentration intervene in the microstructure of biomimetic mineralized collagen and potential osteogenic microenvironment

The absence of a conducive bone formation microenvironment between fractured ends poses a significant challenge in repairing large bone defects. A promising solution is to construct a bone formation microenvironment that mimics natural bone tissue. Biomimetic mineralized collagen possesses a chemical composition and microstructure highly similar to the natural bone matrix, making it an ideal biomimetic bone substitute material. The microstructure of biomimetic mineralized collagen is influenced by various factors, and its biomineralization and microstructure, in turn, affect its physicochemical properties and biological activity. We aimed to utilize mineralization time and solution concentration as variables and employed the polymer-induced liquid precursor strategy to fabricate mineralized collagen with diverse microstructures, to shed light on how mineralization parameters impact the material microstructure and physicochemical properties. We also investigated the influence of microstructure and physicochemical properties on cell biocompatibility and the bone-forming microenvironment. Through comprehensive characterization, we examined the physical and chemical properties of I-EMC under various mineralization conditions and assessed the in vitro and in vivo biocompatibility and osteogenic performance. By investigating the relationship between mineralization parameters, material physicochemical properties, and osteogenic performance, we revealed how microstructures influence cellular behaviors like biocompatibility and osteogenic microenvironment. Encouragingly, mineralization solutions with varying concentrations, stabilized by polyacrylic acid, successfully produced intrafibrillar and extrafibrillar mineralized collagen. Compared to non-mineralized collagen, all mineralized samples demonstrated improved bone-forming performance. Notably, samples prepared with a 1× mineralization solution exhibited relatively smooth surfaces with even mineralization. Extending the mineralization time enhanced the degree of mineralization and osteogenic performance. Conversely, samples prepared with a 2× mineralization solution had rough surfaces with large calcium phosphate particles, indicating non-uniform mineralization. Overall, our research advances the potential for commercial production of mineralized collagen protein products, characterized by dual biomimetic properties, and their application in treating various types of bone defects

SHP-2 Promotes the Maturation of Oligodendrocyte Precursor Cells Through Akt and ERK1/2 Signaling In Vitro

Background: Oligodendrocyte precursor cells (OPCs) differentiate into oligodendrocytes (OLs), which are responsible for myelination. Myelin is essential for saltatory nerve conduction in the vertebrate nervous system. However, the molecular mechanisms of maturation and myelination by oligodendrocytes remain elusive. Methods and Findings: In the present study, we showed that maturation of oligodendrocytes was attenuated by sodium orthovanadate (a comprehensive inhibitor of tyrosine phosphatases) and PTPi IV (a specific inhibitor of SHP-2). It is also found that SHP-2 was persistently expressed during maturation process of OPCs. Down-regulation of endogenous SHP-2 led to impairment of oligodendrocytes maturation and this effect was triiodo-L-thyronine (T3) dependent. Furthermore, overexpression of SHP-2 was shown to promote maturation of oligodendrocytes. Finally, it has been identified that SHP-2 was involved in activation of Akt and extracellular-regulated kinases 1 and 2 (ERK1/2) induced by T3 in oligodendrocytes

Research Progress on regarding the torque control of upper anterior teeth with a lip appliance

The normal torque angle of the maxillary anterior teeth is an important factor in the aesthetics and func⁃ tion of the anterior teeth, and torque control of the front teeth is an extremely important aspect of the correction process. At present, the normal torque angle of the front teeth is among the phase Ⅲ clinical test items recognized by the Ameri⁃ can orthodontic professional committee; consequently, good control of front teeth torque is of great significance to the aesthetics of the upper anterior teeth. In this paper, the influence of a lip appliance on the bad torque of upper anterior teeth and the associated methods of control are reviewed in detail. The advantages and disadvantages of various control methods for the anterior teeth and the significance of correct anterior teeth torque angle are summarized. The existing re⁃ search results indicate that the torsion of a straight arch wire applied directly to individual teeth is too great, making it difficult to enter the groove. Although the bending of the arch wire overcomes these shortcomings, the procedure is cum⁃ bersome; it stimulates the soft tissue of the vestibular groove and increases the patients discomfort. The bending mecha⁃ nism of the rocking chair is more complicated; it is greatly affected by the friction between the arch wire and the brack⁃ et and is not conducive to closing the tooth extraction gap using the sliding method. The portal auxiliary arch and the single bending torque are suitable for correcting the torque angle of a single tooth. Auxiliary arch torque can be used to correct the upright upper anterior teeth during the process of closing the extraction space and after adduction; therefore, this procedure is worth popularizing. However, the accuracy of orthodontic control of anterior teeth torque requires fur⁃ ther study

Effects of Antimony Stress on Photosynthesis and Growth of Acorus calamus

This study was aimed to explore that effects of Sb on physiological parameters of Acorus calamus and the possibility of using A. calamus as a remediation plant. A. calamus potted experiments were conducted using different concentrations (0, 250, 500, 1000, and 2000 mg/kg) of antimony potassium tartrate (Sb3+) (marked as CK, T1, T2, T3, and T4, respectively) and potassium pyroantimonate (Sb5+) (marked as CK, T′1, T′2, T′3, and T′4, respectively). The effects of Sb stress (Sb3+ and Sb5+) on leaf photosynthetic pigments, biomass, photosynthetic characteristics and chlorophyll fluorescence parameters of potted A. calamus were studied. With the rise of Sb3+ concentration from T1 to T4, the leaf pigment contents (chlorophyll a, b, carotenoid), plant height, dry weight, net photosynthetic rate (Pn), stomatal conductance (Gs), evaporation rate (E), PSII maximum photochemical efficiency (Fv/Fm), and PSII electron transfer quantum yield rate (ΦPSII) of A. calamus all reduced, while intercellular CO2 concentration (Ci) significantly increased. The reduction of Pn was mainly induced by non-stomatal limitation. Chlorophyll a/b ratio increased significantly versus the control, while carotenoid/chlorophyll ratio (Car/Chl) first decreased and then increased. The leaf Chl a, Chl b, Car, plant height, dry weight, Pn, Gs, E, Fv/Fm, and ΦPSII all maximized in T′1 (250 mg/kg), but were not significantly different from the control. As the Sb5+ concentration increased from T′2 to T′4, the above indices all decreased and were significantly different from the control. Moreover, intercellular CO2 concentration (Ci) decreased significantly. The reduction of Pn was caused by non-stomatal limitation, indicating the mesophyll cells were damaged. The Car/Chl ratio was stable within 0–500 mg/kg Sb, but decreased in T3 and T4, and rose in T′3 and T′4. After Sb3+ and Sb5+ treatments, translocation factor varied 19.44–27.8 and 19.44–24.86%, respectively. In conclusion, different form Sb3+ treatment, Sb5+ treatment showed a Hormesi effect, as low-concentration treatment promoted A. calamus growth, but high-concentration treatment inhibited its growth. The two forms of Sb both caused unfavorable effects on A. calamus, but the seedlings did not die and were modestly adaptive and Sb-accumulative. A. calamus, which is easily maintained and cultivated, can serve as a good candidate for phytoremediation of water contaminated with Sb

Experimental Study on Constant Speed Control Technology of Hydraulic Drive Pavers

The paver needs superior constant speed performance when paving the pavement. In order to effectively reduce the paver speed fluctuation of the paver, and the wandering deviation from the predetermined track during the paving operation, a control scheme of paver travelling system based on GNSS, Global Navigation Satellite System, is proposed; the scheme can realize open-loop control, closed-loop control, and deviation correction control according to the driver’s choice. During closed-loop control, the setting value and the PID controller output of the left wheel are combined to control the speed of the left wheel, as is the closed-loop control of the right wheel. During the deviation correction control, the coordinate provided by the RTK GNSS receiver and the predetermined trajectory line are used to calculate the lateral deviation of the paver. The lateral deviation is input to the right wheel navigation correction PID algorithm. After the calculation, the correction value of the right wheel speed is obtained, which is input to the right wheel PID controller for the deviation correction control. In this paper, the low constant speed performance of the paver, such as during straight driving, turning driving, and driving when resistance changing, was studied by means of experiments. The test results show that when the test paver was running at a speed of more than 2 m/min, the average speed was almost the same. The higher the average speed was, the more stable the speed was. When the paver was less than 1 m/min, its speed fluctuation tended to increase, and its constant speed performance could not be guaranteed. When the test paver hit a movable obstacle at a speed of 5 m/min, which changed the driving resistance, the average speed of the left and right wheels decreased significantly, with a change of about 2.8%, and there was no significant change in the speed fluctuation of the left and right wheels. At the same time, the wandering deviation test proves that the strait-line travelling wandering deviation was basically controlled within 2.5 cm. Without driver intervention, the wandering deviation of the test paver travelling 50 m decreased by about 97.4%, and the constant speed control fluctuation was within 0.2% when the paver travelled at the speed of 5 m/min

Experimental Study on Constant Speed Control Technology of Hydraulic Drive Pavers

The paver needs superior constant speed performance when paving the pavement. In order to effectively reduce the paver speed fluctuation of the paver, and the wandering deviation from the predetermined track during the paving operation, a control scheme of paver travelling system based on GNSS, Global Navigation Satellite System, is proposed; the scheme can realize open-loop control, closed-loop control, and deviation correction control according to the driver’s choice. During closed-loop control, the setting value and the PID controller output of the left wheel are combined to control the speed of the left wheel, as is the closed-loop control of the right wheel. During the deviation correction control, the coordinate provided by the RTK GNSS receiver and the predetermined trajectory line are used to calculate the lateral deviation of the paver. The lateral deviation is input to the right wheel navigation correction PID algorithm. After the calculation, the correction value of the right wheel speed is obtained, which is input to the right wheel PID controller for the deviation correction control. In this paper, the low constant speed performance of the paver, such as during straight driving, turning driving, and driving when resistance changing, was studied by means of experiments. The test results show that when the test paver was running at a speed of more than 2 m/min, the average speed was almost the same. The higher the average speed was, the more stable the speed was. When the paver was less than 1 m/min, its speed fluctuation tended to increase, and its constant speed performance could not be guaranteed. When the test paver hit a movable obstacle at a speed of 5 m/min, which changed the driving resistance, the average speed of the left and right wheels decreased significantly, with a change of about 2.8%, and there was no significant change in the speed fluctuation of the left and right wheels. At the same time, the wandering deviation test proves that the strait-line travelling wandering deviation was basically controlled within 2.5 cm. Without driver intervention, the wandering deviation of the test paver travelling 50 m decreased by about 97.4%, and the constant speed control fluctuation was within 0.2% when the paver travelled at the speed of 5 m/min

Characterization of steroidal saponins in crude extracts from Dioscorea zingiberensis C. H. Wright by ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry

Steroidal saponins are the major bioactive constituents of Dioscorea zingiberensis C H Wright (D zingiberensis) In this work, ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS/MS) was applied to the separation and characterization of steroidal saponins in crude extracts from D zingiberensis. The results showed that fragment ions from glycosidic and cross-ring cleavages gave a wealth of structural information related to aglycone skeletons, sugar types and the sequence of sugar units. According to the summarized fragmentation patterns, identification of steroidal saponins from D zingiberensis could be fulfilled, even when reference standards were unavailable As a result, a total of thirty-one saponins with five aglycone skeletons, including fourteen new trace saponins, were identified or tentatively elucidated in crude extracts from D zingiberensis based on their retention times, the mass spectrometric fragmentation patterns, and MS and MS/MS data (c) 2010 Elsevier B V All rights reserve

Equivalent stiffness prediction and global buckling analysis using refined analytical model of composite laminated box beam

The analytical model applicable to calculate the equivalent stiffnesses of composite box beam has been refined. The calculation of equivalent stiffness coefficients of composite laminated box beam is simplified and the connection between shear-deformable beam theory and classical laminate theory is established. The equivalent stiffness analytic formulas expressed by beam cross-section geometry and laminate stiffness coefficients are obtained. These analytical formulas are suitable for composite laminated box beam with circumferential uniform stiffness, and accounts for bending- transverse shear and torsiontensile coupling effect. The correctness and precision of refined analytical model is verified by test and finite element method, respectively. The influences of the lay-ups on the elastic coupling of composite structures and their causes are studied. The variation of the equivalent stiffnesses of the laminated box beams with different lay-ups is predicted. The global buckling analysis of composite laminated box beam considering the transverse shear deformation is carried out. The formula of the global buckling critical load is obtained combining with the theoretical formulas of equivalent stiffnesses. The influences of the lay-ups, shear deformation and slenderness ratio on the global buckling critical load are studied

Genetic differences and variation in polysaccharide antioxidant activity found in germplasm resources for Job’s tears (Coix lacryma-jobi L.)

Job’s tears (Coix lacryma-jobi L.) is an ancient plant with high nutritional and medicinal value. In this study, using 11 Chinese germplasm resources for Job’s tears, we examined genetic differences among the germplasms and differences in the in vitro antioxidant activities of coixan, and sought to identify inter-relationships between these two variables. We found that the intraspecific conservation of DNA sequences was high, with ITS regions and cpDNA trnL-F and trnH-psbA non-coding sequences showing no sequence variation, whereas the GBSSI gene showed a certain degree of variation among the different germplasms. EST-SSR analysis also revealed a relatively low level of genetic diversity among the germplasms. Coixan was shown to be an efficient antioxidant, and among the germplasms examined, the LNYX, FJPC, and AHBZ had the highest antioxidant activities. However, none of the four in vitro antioxidant activity indices we assessed were significantly correlated with the geographical origin of the germplasm (latitude and longitude); however, one of them was significantly associated with genetic diversity. Although the factors affecting the antioxidant activity of coixan are complex, the role of heredity should not be ignored. Our findings have implications for the scientific evaluation, identification, and sustainable utilization of the germplasm resources for Job’s tears.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Experimental and Constitutive Model Study on Dynamic Mechanical Behavior of Metal Rubber under High-Speed Impact Loading

The development of lightweight, impact-resistant, and high energy-consuming materials is of great significance for improving the defense capabilities of military equipment. As a new type of damping material, metal rubber has demonstrated great potential for application in the field of impact protection. In this paper, the dynamic mechanical response of metal rubber under a high strain rate is studied, which provides a new idea for developing high-performance protective materials. The stress-strain curves, energy absorption performance, and wave transmission performance of metal rubber at various strain rates were investigated based on a split-Hopkinson pressure bar (SHPB) device. The dynamic stress-strain curve of metal rubber is divided into three stages: elastic stage, plastic stage, and failure stage. The optimal energy absorption efficiency is greater than 0.5, and the maximum value can reach 0.9. The wave transmittance is less than 0.01. The dynamic mechanical tests have proved that metal rubber has excellent energy absorption capacity and impact resistance property. A constitutive model based on Sherwood–Frost was established to predict the dynamic mechanical behavior of metal rubber. The results of comparison between the calculation and the experiment show that the constitutive model can accurately predict the dynamic mechanical performance of metal rubber