Quantitative multi-parameter assessment of age- and gender-related variation of back extensor muscles in healthy adults using Dixon MR imaging.

OBJECTIVES: Investigate sex differences in age-related back extensor muscle degeneration using Dixon MRI and analyze the relationship between quantitative muscle parameters and back muscle strength in healthy adults. METHODS: 105 healthy subjects underwent lumbar Dixon MRI. Fat fraction (FF), cross-sectional area (CSA), functional CSA (FCSA), and relative FCSA (RFCSA) of multifidus muscle (MF) and erector spinae (ES) were quantified. Back extension muscle strength was measured using an external fixation dynamometer. ANOVA with post hoc Tukey correction was used for age group comparisons. Partial and Spearman's correlation analyzed relationships between age, muscle parameters, and muscle strength. RESULTS: MF and ES FF significantly increased with age in both genders (r = 0.55-0.85; p < 0.001). Muscle FF increased prominently for females (40-49 years, MF and 50-59 years, ES) and males (60-73 years, MF and ES). In females, total ES FCSA and RFCSA (r = - 0.42, - 0.37; p < 0.01) correlated with age. While in males, all MF and ES muscle size parameters, except total MF CSA, correlated with age (r = - 0.30 to - 0.58; p < 0.05). Back extension muscle strength correlated with mean FF, total CSA, and total FCAS for MF and ES individually (p < 0.001). The combined MF + ES FCSA correlation coefficient (r = 0.63) was higher than FF (r = - 0.51) and CSA (r = 0.59) (p < 0.001). CONCLUSIONS: Age-related back extensor muscle degeneration varies by muscle type and sex. FCSA has the highest association with back muscle strength compared to FF and CSA. CLINICAL RELEVANCE STATEMENT: The investigation of sex differences in age-related back extensor muscle degeneration utilizing Dixon imaging may hold significant implications for evaluating spine health and enabling earlier intervention. Muscles' FCSA could contribute to acquiring additional evidence for reflecting muscle function change. KEY POINTS: • The multifidus muscle (MF) and erector spinae (ES) fat fraction (FF) increased with age at all lumbar disc levels in females and males. • Age-related changes in muscle morphological quantitative parameters of healthy adults were specific by muscle type and gender. • The muscle functional cross-sectional area (FCSA) measured by Dixon imaging may better monitor back extensor muscle strength changes than muscle FF and cross-sectional area (CSA).

Two-dimensional fullerene-based monolayer materials assembled by C80 and Sc3N@C80.

Construction of two-dimensional (2D) materials using fullerenes as building blocks has attracted particular attention, primarily due to their ability to integrate desired functionalities into devices. However, realization of stable 2D phases of polymerized fullerenes remains a big challenge. Here, we propose two stable 2D monolayer phases with covalently bridged C80 cages, namely α-C80-2D and ß-C80-2D, which are semiconductors with strong absorption in the long wave range and appreciable carrier mobility, respectively. The high stability originates from the bond energy released by the [2+2] cycloaddition polymerization of C80 is greater than the deformation energy of a cage. Starting from α-C80-2D, endohedral incorporation of the Sc3N molecule into each C80 cage leads to 2D semiconductors of α-Sc3N@C80-2D and α'-Sc3N@C80-2D, which possess exceptional stability and diverse physical properties, including unique electronic band structures, strong optical absorption in the visible (VIS) to near-infrared (NIR) regime, and anisotropic optical characteristics. Remarkably, a temperature-induced order-disorder transition in the α-Sc3N@C80-2D phase has been observed at elevated temperatures above 600 K. These findings expand the family of 2D carbon materials and provide useful clue for the potential applications of fullerene-assembled monolayer networks.

Compact polarization transceiver module for fiber optic gyroscopes.

This paper reports a transceiver module with a high polarization extinction ratio (PER) for the polarization-maintaining interferometric fiber optic gyroscope (PM-IFOG). This transceiver utilizes a graded-index lens featuring a slanted face coated with a multilayer film, enabling simultaneous collimation and beam splitting. Configurations of the graded-index splitter lens and the corresponding transceiver module are simulated and designed using the ray matrix method and physical optical propagation. The optical loss of the transceiver module is about 3.77 dB, and the PER exceeds 25 dB. The IFOG prototype is implemented by integrating the transceiver module with a PM sensing coil. The bias instability of the IFOG prototype is evaluated to be 0.51°/h by Allan variance. This research contributes to the reduction in size, weight, power consumption, and cost of PM-IFOG systems.

Core-Packing-Related Vibrational Properties of Thiol-Protected Gold Nanoclusters and Their Excited-State Behavior.

Thiolate-protected gold nanoclusters, with unique nuclearity- and structure-dependent properties, have been extensively used in energy conversion and catalysis; however, the mystery between kernel structures and properties remains to be revealed. Here, the influence of core packing on the electronic structure, vibrational properties, and excited-state dynamics of four gold nanoclusters with various kernel structures is explored using density functional theory combined with time-domain nonadiabatic molecular dynamics simulations. We elucidate the correlation between the geometrical structure and excited-state dynamics of gold nanoclusters. The distinct carrier lifetimes of the four nanoclusters are attributed to various electron-phonon couplings arising from the different vibrational properties caused by core packing. We have identified specific phonon modes that participate in the electron-hole recombination dynamics, which are related to the gold core of nanoclusters. This study paints a physical picture from the geometric configuration, electronic structure, vibrational properties, and carrier lifetime of these nanoclusters, thereby facilitating their potential application in optoelectronic materials.

Correlation between strength/endurance of paraspinal muscles and sagittal parameters in patients with degenerative spinal deformity.

BACKGROUND: Sagittal imbalance is a common cause of low back pain and dysfunction in patients with degenerative spinal deformity (DSD), which greatly affects their quality of life. Strength and endurance are important functional physical indexes for assessing muscle condition. However, the correlation between sagittal parameters and paraspinal muscle strength/endurance is not yet clear. The purpose of this study was to analyze the correlation between strength/endurance of paraspinal muscles and sagittal parameters in patients with DSD. METHODS: There were 105 patients with DSD and 52 healthy volunteers (control group) enrolled. They were divided into the balance group [sagittal vertical axis (SVA) < 5 cm, n = 68] and imbalance group (SVA ≥ 5 cm, n = 37). The maximal voluntary exertion (MVE)/Endurance time (ET) of paravertebral muscles were assessed using the prone position test stand, and the sagittal parameters of the subjects were measured, namely, SVA, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Pearson coefficients were used to assess the correlation between paraspinal muscle MVE/ET and sagittal parameters. RESULTS: MVE and ET of paravertebral muscles in the control group were significantly higher than those in the balance and imbalance groups (P < 0.05), whereas MVE in the balance group was significantly higher than that in the imbalance group (P < 0.05). SVA in the imbalance group was significantly higher than those in the control and balance groups (P < 0.05). SS and TK in the control group were significantly higher than those in the imbalance group (P < 0.05), and PT and PI in the control group were significantly lower than those in the balance and imbalance groups (P < 0.05). LL in the imbalance group was significantly lower than that in the balance and control groups (P < 0.05). MVE, MVE/BH, and MVE/BW of paraspinal muscles in the imbalance group were negatively correlated with SVA and PT. Moreover, they were positively correlated with LL. CONCLUSIONS: Deformity may cause the decrease of MVE and ET of paraspinal muscles in the prone position in patients with DSD. Furthermore, the decline in MVE of paraspinal muscles may be a predisposing factor for the imbalance observed. The decrease of MVE/BW of paraspinal muscles may be involved in spinal compensation, and it is a sensitive indicator for sagittal imbalance and lumbar lordosis.

Isomerism effects in relaxation dynamics of Au24(SR)16thiolate-protected gold nanoclusters.

Understanding the excited state behavior of isomeric structures of thiolate-protected gold nanoclusters is still a challenging task. In this paper, based on grand unified model and ring model for describing thiolate-protected gold nanoclusters, we have predicted four isomers of Au24(SR)16nanoclusters. Density functional theory calculations show that the total energy of one of the predicted isomers is 0.1 eV lower in energy than previously crystallized isomer. The nonradiative relaxation dynamics simulations of Au24(SH)16isomers are performed to reveal the effects of structural isomerism on relaxation process of the lowest energy states, in which that most of the low-excited states consist of core states. In addition, crystallized isomer possesses the shorter e-h recombination time, whereas the most stable isomer has the longer recombination time, which may be attributed to the synergistic effect of nonadiabatic coupling and decoherence time. Our results could provide practical guidance to predict new gold nanoclusters for future experimental synthesis, and stimulate the exploration of atomic structures of same sized gold nanoclusters for photovoltaic and optoelectronic devices.

Effects of combined adjustable Halo-pelvic fixation brace on cervical spine alignment in patients with severe rigid spinal deformity.

OBJECTIVE: To evaluate the effect of continuous traction with a combined adjustable Halo-pelvic fixation brace on the cervical spine alignment in patients with severe rigid spinal deformity and analyze its related factors. METHODS: We conducted a retrospective cohort study of 21 patients with severe rigid spinal deformity treated in our department between 2015 and 2019. All subjects received combined adjustable Halo-pelvic fixation brace traction before secondary orthopedic surgery. The influence of the Halo-pelvic fixation brace on the cervical spine alignment was evaluated by measuring the parameters of lateral cervical X-ray at three time points: before traction, at the end of traction, and 6 months after orthopedic surgery. The correlation between parameter changes and total traction duration was analyzed to explore factors influencing cervical alignment. RESULTS: The C2L-C7L angle was 22.40 ± 15.91° before traction, which decreased to 5.91 ± 6.78° at the end of traction but increased to 14.51 ± 10.07° after orthopedic surgery (BT vs ET p < 0.005, ET vs AOS p < 0.005, BT vs AOS p < 0.005). Accordingly, C2L-C7U angle, C2L-C6L angle, C2L-C6U angle, C2L-C5L angle, C7 or T1 slope, C2-C7 SVA, SCA, C2-T1 Ha, C0 slope, and C0-C2 angle also changed similarly to C2L-C7L angle. Furthermore, moderate correlation was observed between C2L-C7L angle and total traction volume (r = 0.563, p = 0.008) and SCA and traction duration (r = 0.525, p = 0.015). However, no significant correlation was found between other cervical alignment parameters and total traction volume and traction duration. CONCLUSIONS: The continuous traction of a combined adjustable Halo-pelvic fixation brace can affect the cervical spine alignment of patients with severe rigid spinal deformity and straighten the physiological curvature of the cervical spine. However, the sagittal alignment gradually recovers after the traction, without any adverse effects on the orthopedic surgery and global balance after the operation; therefore, this apparatus is worthy of wide application.

Assessment of isokinetic trunk muscle strength and its association with health-related quality of life in patients with degenerative spinal deformity.

BACKGROUND: A considerable portion of the elderly population are increasingly afflicted by degenerative spinal deformity (DSD), which seriously affects patient health-related quality of life (HRQoL). HRQoL index is used across many studies to show correlations between radio-graphical alignment, disability, and pain in patients with DSD. However, imaged structural deformity represents only one aspect for consideration, namely, the disability effect of DSD. We assessed the isokinetic strength of trunk muscle in patients with degenerative spinal deformity (DSD), and investigated its relationship with HRQoL. METHODS: In total, 38 patients with DSD (DSD group) and 32 healthy individuals (control group) were recruited. Both groups were homogeneous for age, weight, height and body mass index (BMI). Assessments were performed using the isokinetic dynamometer IsoMed-2000; trunk extensor, flexor strength and flexion/extension (F/E) ratios were explored concentrically at speeds of 30°, 60° and 120° per second. The grip strength of both hands was measured using a hand-held dynamometer. Visual analogue scale (VAS) scores, the Oswestry Disability Index (ODI), a Roland-Morris disability questionnaire (RDQ), and a 36-item Short Form Health Survey (SF-36) evaluated patient HRQoL. Correlations between trunk strength and HRQoL were analyzed. RESULTS: When compared with the control group, the DSD group showed lower trunk extensor strength at three velocity movements, and higher F/E ratios at 60° and 120°/s (p < 0.05). Both groups exhibited similar trunk flexor strength and grip strength (p > 0.05). In DSD group, trunk extensor strength at 60°/s was negatively associated with ODI and RDQ (p < 0.05). A negative relationship between trunk flexor strength at 120°/s and ODI was also recorded (p < 0.05). In addition, trunk extensor strength at 60°/s and trunk flexor strength at 120°/s were positively correlated with physical functioning and role-physical scores according to the SF-36 (p < 0.05). CONCLUSIONS: We identified isolated trunk extensor myopathy in DSD, which causes an imbalance in trunk muscle strength. Isokinetic trunk extensor strength at 60°/s and trunk flexor strength at 120°/s can predict disability, and decrease physical HRQoL in DSD patients.

Relationship between paravertebral muscle function, pelvic incidence, and health-related quality of life in patients with degenerative spinal deformity.

BACKGROUND: Patients with degenerative spinal deformity often experience symptoms that seriously affect their quality of life, such as low back pain and dysfunction. This study aimed to investigate the relationship between paravertebral muscle function and pelvic incidence (PI) and their effect on health-related quality of life (HRQL) in patients with degenerative spinal deformity. METHODS: A total of 112 patients with degenerative spinal deformity in Southwest Hospital (Chongqing, China) were enrolled. They were divided into groups according to PI angle: high (PI > 60°, n = 37), normal (PI 50°-60°, n = 31), and low (PI < 50°, n = 44). Paravertebral muscle strength and endurance were assessed using the prone external fixation test frame. The sagittal vertical axis (SVA) was measured on X-rays of the spine in an anterolateral position, and all subjects were assessed with the Oswestry Disability Index (ODI), Roland-Morris questionnaire (RMQ), and 36-Item Short Form Health Survey (SF-36). Pearson or Spearman coefficients were used to assess the relationship of paravertebral muscle function with SVA, PI, and health-related quality of life. RESULTS: Maximal voluntary exercise (MVE) in the high-PI group was significantly lower than the MVE of both the normal- and low-PI groups (p < 0.05). There was no significant difference in MVE between the normal- and low-PI groups (p > 0.05). There was no significant difference in endurance time, SVA, ODI, RMQ, and SF-36 among the three groups. Paravertebral muscle MVE was negatively correlated with PI, SVA, ODI, and RMQ (r = - 0.193, - 0.210, - 0.283, - 0.277, p < 0.05). Endurance time of paravertebral muscle was also negatively correlated with SVA, ODI, and RMQ (r = - 0.200, - 0.420, - 0.348, p < 0.05) and positively correlated with SF-36 (r = 0.245, p < 0.05). In addition, paravertebral muscle MVE was positively correlated with the physical functioning score of the SF-36 (r = 0.251, p < 0.05), and the endurance time of paravertebral muscle was positively correlated with the physical functioning, physical role, bodily pain, and social function scores of the SF-36 (r = 0.342, 0.230, 0.209, 0.256, p < 0.05). CONCLUSIONS: High PI may serve as a risk factor for decreased paraspinal muscle strength in patients with degenerative spinal deformities. Early and targeted exercises focusing on paraspinal muscle strength and endurance could potentially be of positive significance in slowing down the progression of sagittal imbalance, alleviating functional disorders, and increasing health-related quality of life in patients with degenerative spinal deformity.

The effects of back extensor strength in different body positions on health-related quality of life in patients with degenerative spinal deformity.

BACKGROUND: Degenerative spinal deformity (DSD) is believed to originate from degeneration of the discs and facet joints and vertebral wedging. Currently, the nosogeny of DSD is not yet fully clarified and there has been no systematic study on the impact of their lower back muscle strength on quality of life. OBJECTIVE: To determine the characteristics of back extensor strength (BES) in different body positions and examine their correlations with health-related quality of life (HQOL) in degenerative spinal deformity (DSD) patients. METHODS: Participants comprised 60 DSD patients and 40 healthy volunteers. Maximal isometric BES was evaluated by dynamometers with the subject in three different positions (standing, prone, sitting). The visual analogue scale (VAS) score, Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMQ), and 36-item Short Form Health Survey (SF-36) score were used to evaluate patient HQOL. Correlations between the BES in different body positions and HQOL were analysed. RESULTS: The BES values in three body positions were significantly smaller in DSD patients than healthy subjects (P< 0.05). The standing BES was found to be negatively associated with ODI and RMQ (R= 0.313, p< 0.05 and R= 0.422, p< 0.01, respectively). A negative relationship between sitting BES and RMQ was also seen (R= 0.271, p< 0.05). In addition, the standing and prone BES were positively correlated with the physical functioning score of the SF-36 (R= 0.471, p< 0.01 and R= 0.289, p< 0.05, respectively), and the sitting BES was positively correlated with the role-physical score of the SF-36 (R= 0.436, p< 0.01). CONCLUSION: The results indicate that the back extensor muscle is compromised in DSD patients and there are differences in predicting the severity of disability and physical HQOL scores with BES in different positions. Standing BES was the most reliable contributor to HQOL among three body positions.

Small diameter expanded polytetrafluoroethylene vascular graft with differentiated inner and outer biomacromolecules for collaborative endothelialization, anti-thrombogenicity and anti-inflammation.

Without differentiated inner and outer biological function, expanded polytetrafluoroethylene (ePTFE) small-diameter (<6 mm) artificial blood vessels would fail in vivo due to foreign body rejection, thrombosis, and hyperplasia. In order to synergistically promote endothelialization, anti-thrombogenicity, and anti-inflammatory function, we modified the inner and outer surface of ePTFE, respectively, by grafting functional biomolecules, such as heparin and epigallocatechin gallate (EGCG), into the inner surface and polyethyleneimine and rapamycin into the outer surface via layer-by-layer self-assembly. Fourier-transform infrared spectroscopy showed the successful incorporation of EGCG, heparin, and rapamycin. The collaborative release profile of heparin and rapamycin lasted for 42 days, respectively. The inner surface promoted human umbilical vein endothelial cells (HUVECs) adhesion and growth and that the outer surface inhibited smooth muscle cells growth and proliferation. The modified ePTFE effectively regulated the differentiation behavior of RAW264.7, inhibited the expression of proinflammatory mediator TNF-α, and up-regulated the expression of anti-inflammatory genes Arg1 and Tgfb-1. The ex vivo circulation results indicated that the occlusions and total thrombus weight of modified ePTFE was much lower than that of the thrombus formed on the ePTFE, presenting good anti-thrombogenic properties. Hence, the straightforward yet efficient synergistic surface functionalization approach presented a potential resolution for the prospective clinical application of small-diameter ePTFE blood vessel grafts.

Isokinetic strength assessment of trunk muscle and its relationship with spinal-pelvic parameters in patients with degenerative spinal deformity.

BACKGROUND: The incidence rate of degenerative spinal deformity (DSD) has gradually increased in the elderly. Currently, the relationship between the functional status of trunk muscle and the spinal-pelvic parameters of DSD patients remains unclear. OBJECTIVE: This paper aims to explore the relationship between the two factors and provide new clues for exploring the mechanism of the occurrence and development of DSD. METHODS: A total of 41 DSD patients treated in our hospital (DSD group) and 35 healthy volunteers (control group) were selected. Muscle strength was evaluated using an IsoMed-2000 isokinetic dynamometer, and the trunk flexor and extensor peak torque (PT) of subjects was measured at a low, medium, and high angular velocity of 30∘/s, 60∘/s, and 120∘/s, respectively. Hand grip strength (HGS) was assessed using an electronic grip dynamometer and Surgimap software was used to measure the spinal-pelvic parameters, including the sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence rate (PI), and PI-LL, and the relationship between trunk muscle function and various parameters was analyzed. RESULTS: Under the three angular velocities, the flexor and extensor PT values in the DSD group were lower than those in the control group, and only the extensor PT showed a statistically significant difference (P< 0.05). There was no significant difference in HGS between the two groups (P> 0.05). In the DSD group, the extensor PT at 30∘/s was significantly negatively correlated with SVA (P< 0.05). At 60∘/s and 120∘/s, the extensor PT was significantly negatively correlated with SVA and PT (P< 0.05). CONCLUSION: Trunk extensor strength is significantly lower in DSD patients than in normal controls. The decline in trunk extensor strength in DSD patients is a type of local muscle dysfunction more closely related to the deformity, which is likely involved in the compensatory mechanism of DSD and may reflect the overall imbalance of the trunk.

Fluorofenidone alleviates liver fibrosis by inhibiting hepatic stellate cell autophagy via the TGF-ß1/Smad pathway: implications for liver cancer.

Objectives: Liver fibrosis is a key stage in the progression of various chronic liver diseases to cirrhosis and liver cancer, but at present, there is no effective treatment. This study investigated the therapeutic effect of the new antifibrotic drug fluorofenidone (AKF-PD) on liver fibrosis and its related mechanism, providing implications for liver cancer. Materials and Methods: The effects of AKF-PD on hepatic stellate cell (HSC) autophagy and extracellular matrix (ECM) expression were assessed in a carbon tetrachloride (CCl4)-induced rat liver fibrosis model. In vitro, HSC-T6 cells were transfected with Smad2 and Smad3 overexpression plasmids and treated with AKF-PD. The viability and number of autophagosomes in HSC-T6 cells were examined. The protein expression levels of Beclin-1, LC3 and P62 were examined by Western blotting. The Cancer Genome Atlas (TCGA) database was used for comprehensively analyzing the prognostic values of SMAD2 and SMAD3 in liver cancer. The correlation between SMAD2, SMAD3, and autophagy-related scores in liver cancer was explored. The drug prediction of autophagy-related scores in liver cancer was explored. Results: AKF-PD attenuated liver injury and ECM deposition in the CCl4-induced liver fibrosis model. In vitro, the viability and number of autophagosomes in HSCs were reduced significantly by AKF-PD treatment. Meanwhile, the protein expression of FN, α-SMA, collagen III, Beclin-1 and LC3 was increased, and P62 was reduced by the overexpression of Smad2 and Smad3; however, AKF-PD reversed these effects. SMAD2 and SMAD3 were hazardous factors in liver cancer. SMAD2 and SMAD3 correlated with autophagy-related scores in liver cancer. Autophagy-related scores could predict drug response in liver cancer. Conclusions: AKF-PD alleviates liver fibrosis by inhibiting HSC autophagy via the transforming growth factor (TGF)-ß1/Smadpathway. Our study provided some implications about how liver fibrosis was connected with liver cancer by SMAD2/SMAD3 and autophagy.

Tuning photoelectron dynamic behavior of thiolate-protected MAu24 nanoclusters via heteroatom substitution.

Heteroatom substitution of gold nanoclusters enables precise tuning of their physicochemical properties at the single-atom level, which has a significant impact on the applications related to excited states including photovoltaics, photocatalysis and photo-luminescence. To this end, understanding the effect of metal exchange on the structures, electronic properties and photoexcited dynamic behavior of nanoclusters is imperative. Combining density functional theory with time-domain nonadiabatic molecular dynamics simulations, herein we explored the effect of metal replacement on the electronic and vibrational properties as well as excited-state dynamics of ligand-protected MAu24(SR)18 (M = Pd, Pt, Cd, and Hg) nanoclusters. At the atomistic level, we elucidate hot carrier relaxation and recombination dynamic behavior with various doping atoms. Such distinct excited-state behavior of MAu24(SR)18 nanoclusters is attributed to different energy gaps and electron-phonon coupling between the donor and acceptor energy levels, owing to the perturbation of nanoclusters by a single foreign atom. The specific phonon modes involved in excited-state dynamics have been identified, which are associated with the MAu12 core and ligand rings. This time-dependent excited-state dynamic study fills the gap between structure/composition and excited-state dynamic behavior of MAu24(SR)18 nanoclusters, which would stimulate the exploration of their applications in photoenergy storage and conversion.

Nanofibrous tissue engineering scaffold with nonlinear elasticity created by controlled curvature and porosity.

Micro-crimped fibers have been widely used in the field of tissue repair to mimic the natural tissue structure and mechanical properties. However, the electrospun nanofibrous membrane is a kind of dense structure, which cannot meet the requirements of mechanical properties and permeability. In this study, we prepared nanofibrous scaffold with controllable porosity and crimpness by sacrificing fiber components and releasing residual stress. The results show that the crimpness of the fiber is positively related to the porosity, and with the increase of porosity, the fiber crimpness increases greatly. Meanwhile, the scaffold modulus was reduced by 86% and the elongation at break doubled, which is similar to natural blood vessels. Moreover, it is found that the porous micro-crimped fiber scaffold promotes the adhesion and diffusion of endothelial cells, and facilitates the rapid endothelialization of the scaffold, which has a great potential for practical application.

Efficient Photoexcited Charge Separation at the Interface of a Novel 0D/2D Heterojunction: A Time-Dependent Ultrafast Dynamic Study.

To achieve efficient conversion and avoid loss of solar energy, ultrafast charge separation and slow electron-hole recombination are desired. Combining time-dependent density functional theory (TD-DFT) with nonadiabatic molecular dynamics, Au9(PH3)8/MoS2, as a prototype for zero-dimensional/two-dimensional (0D/2D) heterojunction, has been demonstrated to present excellent light absorption capacity and effective charge separation characteristics. In the heterojunction, photoexcitation of the Au9(PH3)8 nanocluster drives an ultrafast electron transfer from Au9(PH3)8 to MoS2 within 20 fs, whereas photoexcitation of the MoS2 nanosheet leads to hole transfer from MoS2 to Au9(PH3)8 within 680 fs. The strong nonadiabatic coupling and prominent density overlap are responsible for the faster electron separation relative to hole separation. In competition with the charge separation, electron-hole recombination requires 205 ns, ensuring an effective carrier separation. Our atomistic TD-DFT simulation provides valuable insights into the photocarrier dynamics at the Au9(PH3)8/MoS2 interface, which would stimulate the exploration of 0D/2D hybrid materials for photovoltaic and optoelectronic devices.

Preparation of gelatin-based hydrogels with tunable mechanical properties and modulation on cell-matrix interactions.

Natural polymer material-based hydrogels normally show inferior mechanical stability and strength to bear large deformation and cyclic loading, therefore their applications in food, biomedical and tissue engineering fields are greatly limited. In this study, gelatin-based hydrogels with remarkable stability, as well as tunable mechanical properties, were prepared via a facile method known as the Hofmeister effect. The higher concentration of potassium sulfatesolution resulted in more dehydration and molecular chain folding, thus the treated hydrogels showed significantly improved tensile and compressive modulus, and decreased equilibrium swelling ratio, as revealed by scanning electron microscopy (SEM), Fourier transform infraredspectroscopy (FTIR), and mechanical tests, etc. Additionally, the reinforced hydrogels were recoverable and biocompatible to modulate the proliferation behavior of human umbilical vein endothelial cells. In conclusion, this paper provides a facile reference for tuning mechanical properties of gelatin-based hydrogels and cell-hydrogel interactions, which show potential capacity in tissue engineering and biomedical fields.

PDLIM5 Affects Chicken Skeletal Muscle Satellite Cell Proliferation and Differentiation via the p38-MAPK Pathway.

Skeletal muscle satellite cell growth and development is a complicated process driven by multiple genes. The PDZ and LIM domain 5 (PDLIM5) gene has been proven to function in C2C12 myoblast differentiation and is involved in the regulation of skeletal muscle development. The role of PDLIM5 in chicken skeletal muscle satellite cells, however, is unclear. In this study, in order to determine whether the PDLIM5 gene has a function in chicken skeletal muscle satellite cells, we examined the changes in proliferation and differentiation of chicken skeletal muscle satellite cells (SMSCs) after interfering and overexpressing PDLIM5 in cells. In addition, the molecular pathways of the PDLIM5 gene regulating SMSC proliferation and differentiation were analyzed by transcriptome sequencing. Our results show that PDLIM5 can promote the proliferation and differentiation of SMSCs; furthermore, through transcriptome sequencing, it can be found that the differential genes are enriched in the MAPK signaling pathway after knocking down PDLIM5. Finally, it was verified that PDLIM5 played an active role in the proliferation and differentiation of chicken SMSCs by activating the p38-MAPK signaling pathway. These results indicate that PDLIM5 may be involved in the growth and development of chicken skeletal muscle.

Endothelial Cell Migration Regulated by Surface Topography of Poly(ε-caprolactone) Nanofibers.

The study of cell migration on biomaterials is of great significance in tissue engineering and regenerative medicine. In recent years, there has been increasing evidence that the physical properties of the extracellular matrix (ECM), such as surface topography, affect various cellular behaviors such as proliferation, adhesion, and migration. However, the biological mechanism of surface topography influencing cellular behavior is still unclear. In this study, we prepared polycaprolactone (PCL) fibrous materials with different surface microstructures by solvent casting, electrospinning, and self-induced crystallization. The corresponding topographical structure obtained is a two-dimensional (2D) flat surface, 2.5-dimensional (2.5D) fibers, and three-dimensional (3D) fibers with a multilevel microstructure. We then investigated the effects of the complex topographical structure on endothelial cell migration. Our study demonstrates that cells can sense the changes of micro- and nanomorphology on the surface of materials, adapt to the physical environment through biochemical reactions, and regulate actin polymerization and directional migration through Rac1 and Cdc42. The cells on the nanofibers are elongated spindles, and the positive feedback of cell adhesion and actin polymerization along the fiber direction makes the plasma membrane continue to protrude, promoting cell polarization and directional migration. This study might provide new insights into the biomaterial design, especially those used for artificial vascular grafts.

Corrigendum to 'Phosphorylation inhibition of protein-tyrosine phosphatase 1B tyrosine-152 induces bone regeneration coupled with angiogenesis for bone tissue engineering' [Bioactive Mater. Vol. 6, Issue 7, Pages 2039-2057].

[This corrects the article DOI: 10.1016/j.bioactmat.2020.12.025.].