Imaging the dynamics of messenger RNA with a bright and stable green fluorescent RNA.

Fluorescent RNAs (FRs) provide an attractive approach to visualizing RNAs in live cells. Although the color palette of FRs has been greatly expanded recently, a green FR with high cellular brightness and photostability is still highly desired. Here we develop a fluorogenic RNA aptamer, termed Okra, that can bind and activate the fluorophore ligand ACE to emit bright green fluorescence. Okra has an order of magnitude enhanced cellular brightness than currently available green FRs, allowing the robust imaging of messenger RNA in both live bacterial and mammalian cells. We further demonstrate the usefulness of Okra for time-resolved measurements of ACTB mRNA trafficking to stress granules, as well as live-cell dual-color superresolution imaging of RNA in combination with Pepper620, revealing nonuniform and distinct distributions of different RNAs throughout the granules. The favorable properties of Okra make it a versatile tool for the study of RNA dynamics and subcellular localization.

A novel means of capitate distraction lengthening for end-stage Kienböck's disease.

We present a patient with Kienböck's disease treated with a novel technique of capitate distraction lengthening using two wires in the proximal capitate and two in the ulna.

Spatiotemporal control of RNA metabolism and CRISPR-Cas functions using engineered photoswitchable RNA-binding proteins.

RNA molecules perform various crucial roles in diverse cellular processes, from translating genetic information to decoding the genome, regulating gene expression and catalyzing chemical reactions. RNA-binding proteins (RBPs) play an essential role in regulating the diverse behaviors and functions of RNA in live cells, but techniques for the spatiotemporal control of RBP activities and RNA functions are rarely reported yet highly desirable. We recently reported the development of LicV, a synthetic photoswitchable RBP that can bind to a specific RNA sequence in response to blue light irradiation. LicV has been used successfully for the optogenetic control of RNA localization, splicing, translation and stability, as well as for the photoswitchable regulation of transcription and genomic locus labeling. Compared to classical genetic or pharmacologic perturbations, LicV-based light-switchable effectors have the advantages of large dynamic range between dark and light conditions and submicron and millisecond spatiotemporal resolutions. In this protocol, we provide an easy, efficient and generalizable strategy for engineering photoswitchable RBPs for the spatiotemporal control of RNA metabolism. We also provide a detailed protocol for the conversion of a CRISPR-Cas system to optogenetic control. The protocols typically take 2-3 d, including transfection and results analysis. Most of this protocol is applicable to the development of novel LicV-based photoswitchable effectors for the optogenetic control of other RNA metabolisms and CRISPR-Cas functions.

[Analysis of the effectiveness of sequential plate internal fixation in correction of Madelung deformity after ulnar osteotomy and shortening].

Objective: To investigate the effectiveness of sequential plate internal fixation in the correction of Madelung deformity after ulnar osteotomy and shortening. Methods: The clinical data of 13 patients with Madelung deformity admitted between September 2015 and July 2021 were retrospectively analyzed. There were 5 males and 8 females with an average age of 18.3 years ranging from 17 to 23 years. The disease duration ranged from 12 to 24 months, with an average of 17 months. Three cases had a clear history of trauma. All patients had external radial deviation deformity and limited movement of the ulnar deviation, and the ulnar impact pain was significant during ulnar deviation movement; 9 patients had limited wrist joint supination movement, and the supination movement was normal. In the first stage, ulnar osteotomy and shortening combined with external fixator were used to correct wrist deformity in 13 patients. After operation, bone transfer was performed 6 times per day, with adjustments made every 4 hours, which was 1 mm per day. After the osteotomy was in place, the ulnar plate internal fixation was performed to reconstruct the ulnar stability in the second stage. The Cooney wrist joint score was used to assess the pain, function, range of motion, flexion and extension range of motion, and grip strength of the wrist joint before operation and before the removal of internal fixator. The subjective feeling and appearance satisfaction of patients were recorded. Results: After the second-stage operation, all the 13 patients were followed up 10-22 months, with an average of 15 months. The deformity of wrist joint disappeared after operation, and the flexion, extension, and ulnar deviation were basically normal. There was no complication such as ulnar impingement sign, nonunion or infection. Wrist function, pain, and range of motion were significantly improved after operation, except for 1 patient who had no significant improvement in rotation and pain. The ulnar internal fixator was removed at 10-18 months after the second-stage operation. The scores of pain, function, range of motion, flexion and extension range of motion, and grip strength in the Cooney wrist score before removal of internal fixator significantly improved when compared with those before operation ( P<0.05). Subjective and appearance satisfaction of patients were excellent in 9 cases, good in 3 cases, and fair in 1 case. Conclusion: Ulnar osteotomy and shortening with sequential plate internal fixation for correction of Madelung deformity, with mild postoperative pain, can effectively avoid bone nonunion, improve wrist joint function, and have significant effectiveness.

Aerobic Exercise in Male Mice Prevents Ventilator-Induced Lung Injury by Inhibiting Mitochondrial Damage from sirt1 Dysregulation.

BACKGROUND: Ventilator-induced lung injury (VILI) is a common complication of mechanical ventilation under general anesthesia. Regular aerobic exercise before surgery improves postoperative recovery and reduces postoperative pulmonary complications, but the mechanism driving this protective effect is unclear. METHODS: To determine how aerobic exercise prevents VILI, we investigated the effects of exercise and mechanical ventilation on the lungs of male mice and the effects of AMPK stimulation (simulating exercise) and cyclic stretching on human lung microvascular endothelial cells (HLMVEC). Sirtuin 1 (Sirt1) knockdown male mice were generated to explore the regulating mechanisms of sirt1 on mitochondrial function in male mice after mechanical ventilation was explored. Western blot, flow cytometry, live cell imaging, and mitochondrial function evaluations were used to determine the protective effects of aerobic exercise in preventing mitochondrial damage in VILI. RESULTS: Mitochondrial function and cell junctions were destroyed by mechanical ventilation in male mice or cyclic stretching in HLMVEC, a model of VILI. However, mitochondrial function and cell junction dysfunction were improved by exercise before mechanical ventilation (male mice) or treatment with AMPK before cyclic stretching (HLMVEC). p66shc, a marker of oxidative stress, was increased, and PINK1, a marker of mitochondrial autophagy, was decreased by mechanical ventilation or cyclic stretching. Sirt1 knockdown increased p66shc and decreased PINK1. Increased sirt1 expression was observed in the exercise and exercise + ventilation groups, suggesting that sirt1 inhibits mitochondrial damage in VILI. CONCLUSIONS: Mechanical ventilation induces mitochondrial damage in lung cells and leads to VILI. Regular aerobic exercise before ventilation may prevent VILI by improving mitochondrial function.

Titanium elastic nails vs locking plate in pediatric subtrochanteric femur fractures: A systematic review and meta-analysis.

Objective: Titanium elastic nails (TENs) and locking plates (LPs) are currently the main internal fixation for treating pediatric subtrochanteric femur fractures, and the optimal choice of internal fixation is controversial. This study aimed to systematically evaluate the effectiveness and safety of TENs and LPs in treating subtrochanteric fractures in children to provide a theoretical basis and reference for clinical treatment. Methods: The literature related to TENs and LPs for treating subtrochanteric fractures in children was searched using the CNKI, PubMed, Cochrane, Embase, and Web of Science, and the search time frame was from the establishment of the database to October 2022. Two evaluators screened the literature according to the inclusion and exclusion criteria and extracted relevant data. Meta-analysis was performed using Stata14.0 software. Results: A total of 9 studies with 407 patients with subtrochanteric femur fractures were included in the final screening, including 210 cases with TENs and 197 cases with LPs. Meta-analysis results showed that compared with the locking plate, TEN had a shorter operative time [WMD = -1.3, 95%CI(-1.94,-0.66), p < 0.01], less intraoperative bleeding [WMD = -84.45, 95%CI(-111.09, -57.82), p < 0.01], shorter fracture healing time [WMD = -1.3, 95%CI(-1.94,-0.66), P < 0.01], shorter hospital stays [WMD = -2.80, 95% CI(-4.63,-0.98), p < 0.01], and earlier full weight bearing [SMD = -0.48, 95% CI(-0.91,-0.04), p < 0.05] but more intraoperative fluoroscopy [WMD = 28.23, 95% CI(15.22,41.25), p < 0.05]. The overall complication rate was high [OR = 3.52, 95% CI(1.96,6.34), p < 0.05], and the postoperative period was prone to angulation, rotation, and inversion deformity [OR = 3.68, 95% CI(1.40, 9.68), p < 0.05]. No significant difference in the incidence of lower limb inequality between the two types of internal fixation [OR = 0.83, 95% CI(0.38, 1.85), p > 0.05] and no significant difference in the Harris score of the hip at the last follow-up between the two types of internal fixation [WMD = -0.67, 95% CI(-2.01,0.67), p > 0.05] were found. Conclusion: In comparison to LPs, TENs have a shorter operation time, less intraoperative bleeding, and a shorter fracture healing time, and the child can be fully weight-bearing earlier. Locking plates can reduce the operator's x-ray exposure, and the incidence rate of postoperative angulation, rotation, and inversion deformity is low. Therefore, TENs and LPs are the best internal fixation methods for treating subtrochanteric fractures in children.

Genetically predicted obesity and risk of hip osteoarthritis.

OBJECTIVES: To determine the causal association between genetically predicted obesity and the risk of hip osteoarthritis. METHODS: We performed two-sample Mendelian randomization (MR) analysis to analyze the association between body mass index (BMI) and hip osteoarthritis using pooled-level genome-wide association study (GWAS) data. The inverse variance weighted (IVW), MR‒Egger, and weighted median methods were used to estimate the causal association. In addition, we applied the MR Steiger filtering method, MR robust adjusted profile score (MR.RAPS) methods, and the MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) global test to examine and address potential horizontal pleiotropy. RESULTS: We found a causal relationship between genetically predicted BMI and the risk of hip osteoarthritis by the IVW method [OR = 1.45, 95% confidence interval (CI) = 1.04-2.00, P = 0.02]. In the sensitivity analysis, the results of the MR‒Egger and weighted median methods revealed similar estimations but with a wide CI with lower precision. The funnel plot, MR-Egger intercept, and MR-PRESSO all indicated the absence of a directional pleiotropic effect. In addition, no heterogeneity was observed in the present analysis. Therefore, the result of IVW is most suitable and reliable for the present MR analysis. CONCLUSION: There is a causal relationship between obesity and a higher risk of hip osteoarthritis, suggesting that weight management may be an intervention for the prevention and management of hip osteoarthritis. LEVEL OF EVIDENCE: Bioinformatics, Basic science.

PGF2α facilitates pathological retinal angiogenesis by modulating endothelial FOS-driven ELR+ CXC chemokine expression.

The pathological retinal angiogenesis often causes blindness. Current anti-angiogenic therapy for proliferative retinopathy targets the vascular endothelial growth factor (VEGF), but many patients do not radically benefit from this therapy. Herein, we report that circulating prostaglandin (PG) F2α metabolites were increased in type 2 diabetic patients with proliferative retinopathy, and the PGF2α receptor (Ptgfr) was upregulated in retinal endothelial cells (ECs) from a mouse model of oxygen-induced retinopathy (OIR). Further, disruption of the PTGFR receptor in ECs attenuated OIR in mice. PGF2α promoted the proliferation and tube formation of human retinal microvascular endothelial cells (HRMECs) via the release of ELR+ CXC chemokines, such as CXCL8 and CXCL2. Mechanistically, the PGF2α /PTGFR axis potentiated ELR+ CXC chemokine expression in HRMECs through the Gq /CAMK2G/p38/ELK-1/FOS pathway. Upregulated FOS-mediated ELR+ CXC chemokine expression was observed in retinal ECs from PDR patients. Moreover, treatment with PTGFR inhibitor lessened the development of OIR in mice in a CXCR2-dependent manner. Therefore, inhibition of PTGFR may represent a new avenue for the treatment of retinal neovascularization, particularly in PDR.

Aerobic exercise alleviates ventilator-induced lung injury by inhibiting NLRP3 inflammasome activation.

BACKGROUND: Ventilator-induced lung injury (VILI) is caused by stretch stimulation and other factors related to mechanical ventilation (MV). NOD-like receptor protein 3 (NLRP3), an important innate immune component, is strongly associated with VILI. This study aimed to investigate the effect and mechanisms of aerobic exercise (EX) on VILI. METHODS: To test the effects of the PKC inhibitor bisindolylmaleimide I on PKC and NLRP3, male C57BL/6 mice (7 weeks old, 19 ~ 23 g) were randomly divided into four groups: control group(C), bisindolylmaleimide I-pretreated group(B), MV group, and bisindolylmaleimide I-pretreated + MV (B + MV) group. The mice were pretreated with bisindolylmaleimide I through intraperitoneal injection (0.02 mg/kg) 1 h before MV. MV was performed at a high tidal volume (30 ml/kg). To explore the ameliorative effect of EX on VILI, the mice were randomly divided into C group, MV group, EX group and EX + MV group and subjected to either MV or 5 weeks of EX training. After ventilation, haematoxylin-eosin (HE) staining and wet/dry weight ratio was used to assess lung pathophysiological changes. PKCɑ, P-PKCɑ, ASC, procaspase-1, caspase-1, pro-IL-1ß, IL-1ß, NLRP3 and occludin (tight junction protein) expression in lung tissues was determined by Western blotting. The level of IL-6 in alveolar lavage fluid was determined by ELISA. RESULTS: NLRP3, P-PKCɑ, and PKCɑ levels were inceased in MV group, but bisindolylmaleimide I treatment reversed these changes. Inhibition of PKC production prevented NLRP3 activation. Moreover, MV increased ASC, procaspase-1, caspase-1, pro-IL-1ß, and IL1ß levels and decreased occludin levels, but EX alleviated these changes. HE staining and lung injury scoring confirmed an absence of obvious lung injury in C group and EX group. Lung injury was most severe in MV group but was improved in EX + MV group. Overall, these findings suggest that MV activates the NLRP3 inflammasome by activating PKCɑ and inducing occludin degradation, while Exercise attenuates NLRP3 inflammasome and PKCɑ activation. Besides, exercise improves cyclic stretch-induced degradation of occludin. CONCLUSION: PKC activation can increase the level of NLRP3, which can lead to lung injury. Exercise can reduce lung injury by inhibiting PKCɑ and NLRP3 activation. Exercise maybe a potential measure for clinical prevention of VILI.

Fabry-Perot resonance-suppressed double-layer metal mesh window for electromagnetic interference shielding.

Traditional electromagnetic interference shielding windows that can simultaneously reflect microwaves and transmit visible light are usually fabricated by depositing one metal mesh layer on the surface of the window. However, such a structure always suffers from strong Fabry-Perot resonance (FPR), which leads to the decline of shielding effectiveness (SE). Here, we analyze the mechanism of FPR from a perspective of the equivalent circuit model and further report a facile approach to minimize the FPR by depositing another high-resistance mesh layer on the back side of the shielding window, which can greatly reduce reflected waves, ensuring that interference cannot be formed. Simulation results prove that FPR can be effectively eliminated by the proposed method, and experiments further show that for a shielding window made with Schott B270 glass plate, the SE can be enhanced by 6.3 dB (76.6% energy attenuation) at declining points, while transmittance is only reduced by 1.6%.

[Characterization of electrophysiological properties and changes in gene expression in basket cells during the postnatal development of mouse prefrontal cortex].

This study aims to explore the electrophysiological properties and changes in gene expression of basket cells, a unique population of GABAergic interneurons expressing parvalbumin (PV), during the postnatal development of mouse prefrontal cortex (PFC). Toward this goal, we took use of the G42 transgenic mouse line which specifically expresses enhanced green fluorescent protein (EGFP) in basket cells. The brain slices of PFC were prepared from the postnatal 7 (P7), 14 (P14) and 21 days (P42) G42 mice and whole-cell patch clamp recording was performed in basket cells. In addition, we sorted the basket cells by flow cytometry and analyzed their transcription profiling on P7, P14, and P21 using RNA-seq technology. The results showed that the resting membrane potential and membrane input resistance decreased gradually from P7 to P21. The amplitude and duration of action potential of basket cells increased and decreased from P7 to P21, respectively. In contrast, the threshold of action potential of basket cells did not have a significant change from P7 to P21. The frequency of spontaneous excitatory postsynaptic currents (sEPSCs) of basket cells increased gradually, while the amplitudes of sEPSCs of basket cells remained constant from P7 to P21. RNA sequencing from basket cells revealed that the expression of 22 and 660 genes was upregulated and downregulated from P7 to P14, respectively. By contrast, the expression of 107 and 69 genes was upregulated and downregulated from P14 to P21, respectively. The differentially expressed genes in basket cells from P7 to P21 were significantly enriched in pathways such as neuron apoptotic process, mRNA processing, Golgi vesicle transport and axon guidance. Altogether, we characterized electrophysiological properties and changes in gene expression of basket cells during the postnatal development in mouse PFC. These results provide insight into the mechanisms underlying the development of basket cells in mouse cortex.

Prognostic factors for mortality in bullous pemphigoid: A systematic review and meta-analysis.

OBJECTIVE: To systematically evaluate the prognostic factors for mortality in bullous pemphigoid. METHODS: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, China Biology Medicine disc and Wanfang Database were searched to collect literature on the prognostic factors for mortality in bullous pemphigoid. The quality of studies was assessed by Newcastle-Ottawa Quality Assessment Scale. Two researchers extracted relevant data and scored study quality independently. The hazard ratio (HR) was calculated using the random effects model. Study heterogeneity was assessed using both Cochran's Q test and I2 statistics. The causes of heterogeneity were assessed by subgroup analysis and/ or sensitivity analysis when heterogeneity was significant. When ten or more studies were included as outcome indicators, publication bias was evaluated by funnel plot and Egger's test. RESULTS: Out of a total of 1,546 articles retrieved, 15 studies involving 2,435 patients were included. The meta-analysis showed that the mortality of patients with bullous pemphigoid increased with positive bullous pemphigoid 180 antibody (HR = 1.85, 95%CI: 1.25~2.75, P = 0.002); concomitant dementia (HR = 2.26, 95%CI: 1.43~3.59, P<0.001); stroke (HR = 2.09, 95% CI: 1.23-3.55, P = 0.007); heart disease (HR = 1.96, 95% CI: 1.41-2.73, P<0.001) and diabetes mellitus (HR = 2.39, 95% CI: 1.55-3.69, P<0.001). Sex, positive indirect immunofluorescence and hypertension were not associated with prognosis. CONCLUSION: Positive bullous pemphigoid 180 antibody, dementia, stroke, heart disease and diabetes mellitus were the prognostic factors for mortality in bullous pemphigoid.

Cyclized Polyacrylonitrile as a Promising Support for Single Atom Metal Catalyst with Synergistic Active Site.

Metal single atom catalysts (SAC) have been successfully used in heterogeneous catalysis but developing a scalable and economic support for SAC is still a great challenge. Here, cyclized polyacrylonitrile (CPAN) is proposed as a promising support for single atom metal catalysts. CPAN can be easily prepared from cheap industrial product polyacrylonitrile (PAN), which has excellent processability. A series of SAC on CPAN (M/CPAN, M = Ag, Cu, Ru) are designed and the catalytic activities of the as synthesized M/CPAN are investigated by the model reduction reaction of p-nitrophenol (4-NP). M/CPAN presents excellent catalytic performance with high stability and theoretical calculations elucidate that Ag/CPAN synergistically catalyze 4-NP reduction following the Langmuir-Hinshelwood (L-H) mechanism with 4-NP preferentially adsorbing at the Ag sites and H adsorbing at the bridge C sites. These results, for the first time, reveal that the single atom on CPAN can catalyze 4-NP reduction efficiently. This methodology provides a convenient route for the preparation of a variety of SAC, and this strategy is readily scalable and holds great potential in catalytic applications.

Dopamine D2 receptor regulates cortical synaptic pruning in rodents.

Synaptic pruning during adolescence is important for appropriate neurodevelopment and synaptic plasticity. Aberrant synaptic pruning may underlie a variety of brain disorders such as schizophrenia, autism and anxiety. Dopamine D2 receptor (Drd2) is associated with several neuropsychiatric diseases and is the target of some antipsychotic drugs. Here we generate self-reporting Drd2 heterozygous (SR-Drd2+/-) rats to simultaneously visualize Drd2-positive neurons and downregulate Drd2 expression. Time course studies on the developing anterior cingulate cortex (ACC) from control and SR-Drd2+/- rats reveal important roles of Drd2 in regulating synaptic pruning rather than synapse formation. Drd2 also regulates LTD, a form of synaptic plasticity which includes some similar cellular/biochemical processes as synaptic pruning. We further demonstrate that Drd2 regulates synaptic pruning via cell-autonomous mechanisms involving activation of mTOR signaling. Deficits of Drd2-mediated synaptic pruning in the ACC during adolescence lead to hyper-glutamatergic function and anxiety-like behaviors in adulthood. Taken together, our results demonstrate important roles of Drd2 in cortical synaptic pruning.

Demonstration of Thermally Tunable Multi-Band and Ultra-Broadband Metamaterial Absorbers Maintaining High Efficiency during Tuning Process.

Metamaterial absorbers (MMAs) with dynamic tuning features have attracted great attention recently, but most realizations to date have suffered from a decay in absorptivity as the working frequency shifts. Here, thermally tunable multi-band and ultra-broadband MMAs based on vanadium dioxide (VO2) are proposed, with nearly no reduction in absorption during the tuning process. Simulations demonstrated that the proposed design can be switched between two independently designable multi-band frequency ranges, with the absorptivity being maintained above 99.8%. Moreover, via designing multiple adjacent absorption spectra, an ultra-broadband switchable MMA that maintains high absorptivity during the tuning process is also demonstrated. Raising the ambient temperature from 298 K to 358 K, the broadband absorptive range shifts from 1.194-2.325 THz to 0.398-1.356 THz, while the absorptivity remains above 90%. This method has potential for THz communication, smart filtering, detecting, imaging, and so forth.

Transparent ultra-wideband double-resonance-layer metamaterial absorber designed by a semiempirical optimization method.

In this study, a transparent ultra-wideband double-resonance-layer absorber was designed using a semiempirical optimization method. In this method, an equivalent circuit model, genetic algorithm, and parameter fitting are employed to reduce the computation time and improve the design flexibility. Simulations and measurements show that the as-designed absorber can achieve ultrawide microwave absorption in the range of 2.00 to 11.37 GHz with a fractional bandwidth of 140.2%. Furthermore, electric field and surface current distributions show that the broad bandwidth was derived from the good matching of the absorption peaks in the two resonance layers. In addition, the target waveband of the as-designed absorber covered the wavebands of WiFi and radio-frequency identification, as well as part of the 5G waveband. This makes the proposed absorber a good candidate for daily electromagnetic pollution reduction.

Tunable and transparent broadband metamaterial absorber with water-based substrate for optical window applications.

A tunable and transparent metamaterial absorber (MMA) with a water-based substrate is presented, with high optical transparency and broadband microwave absorptivity. In the material structure, indium-tin-oxide (ITO) films are included as the resonant pattern and reflective layers, and distilled water is combined with polymethyl methacrylate (PMMA) to produce the dielectric substrate. By effectively designing its structural parameters, the proposed absorber achieves >90% absorptivity, covering an ultrawide frequency range of 5.8-16.2 GHz, while the average optical transmittance is ∼70.18% over a wavelength range of 400-800 nm. Moreover, owing to a specific design feature, the absorber has high polarization insensitivity and wide-incident-angle stability for transverse electric (TE) and transverse magnetic (TM) polarization waves. Furthermore, the absorption properties of the absorber can be further tuned by controlling the thickness of the water substrate. Both numerical simulations and experimental measurements demonstrate the excellent performance of the device, showing its strong potential for use in optical windows within military and medical equipment.

[Advances on research of physical environment affecting stem cell differentiation in ligament tissue engineering].

Ligament tissue engineering is currently a novel approach to the treatment of ligament injury, which can replace the deficiency of autografts. Ligament tissue engineering consists of four basic elements:seed cells, nanoscaffolds, growth factors, and mechanical stimulation. At present, the main problem in ligament tissue engineering is how to control seed cells to ligament cells more controllly. The study found that each physical property of the natural bio ligament and mechanical stimulation (uniaxial stretching) plays an important role in the differentiation of stem cells into ligament cells. Therefore, the design of nanofiber scaffolds must consider the elastic modulus of the material and the material. Structure(material arrangement, porosity and diameter, etc.), elastic modulus and material structure in different ranges will guide cells to differentiate into different lineages. Considering that the ligament is the main force-bearing tissue of the human body, mechanical stimulation is also essential for stem cell differentiation, especially uniaxial stretching, which best meets the stress of the ligament in the body. A large number of studies have found the frequency and amplitude of stretching. And time will also lead the cells to differentiate in different directions. RhoA/ROCK plays a regulatory role in cytoskeletal remodeling and cell differentiation. It is also found that RhoA/ROCK protein participates in the process of nanofiber arrangement and uniaxial stretching to guide stem cells to differentiate into ligament cells, specifically how to influence stem cell differentiation. It is not clear at present that understanding the effects of physical properties on stem cell differentiation and understanding the mechanism of action of RhoA/ROCK protein will provide a new theoretical basis for further optimization of ligament tissue engineering.

High-performance broadband electromagnetic interference shielding optical window based on a metamaterial absorber.

An excellently transparent metamaterial-based electromagnetic interference (EMI) shielding window with broadband absorption is presented theoretically and demonstrated experimentally. The window is composed of double split circular ring (SCR) elements whose absorption spectra feature two mild resonant peaks. Indium-tin-oxide (ITO) with resonant patterns is utilized as the material to induce high ohmic loss and broaden the absorption bandwidth. The window achieves strong absorptivity, > 90%, covering an ultrawide frequency range of 7.8-18.0 GHz. Moreover, the measured shielding effectiveness (SE) of the window is > 18.25 dB, at 7.0-18.0 GHz, while the average optical transmittance is fixed at ∼73.10% in the visible-near-infrared (Vis-NIR) region of 400-1,500 nm. Further, the absorption mechanism is revealed by designing an equivalent circuit model and studying the distributions of the electric field and surface currents of the structure. Furthermore, a specific design feature also makes our device insensitive to the incident angle and the polarization state of the impinging microwave. The 90% absorption and shielding performance of the proposed optical window avail it for a wide range of great potential applications, such as the displays of military and medical precision devices.

Large-scale, low-cost, broadband and tunable perfect optical absorber based on phase-change material.

Metamaterial-based electromagnetic absorbers have attracted much attention recently, but most previous realizations suffer from issues of narrow bandwidth, time-consuming and high-cost fabrication methods, and/or fixed functionalities, and so are unfavorable for practical applications. Here, we demonstrate experimentally a large-scale, broadband, polarization-independent, and tunable metamaterial absorber, which works for both visible and near-infrared light. A lithography-free and low-cost method was utilized to fabricate a centimeter-sized metamaterial sample in a metal-insulator-metal (MIM) configuration with nano-scale precision, in which a phase-change material, Ge2Sb2Te5 (GST), was adopted as the insulating spacer of the MIM structure. With two different resonance mechanisms working together, the proposed device was shown to exhibit high absorptivity (>80%) within a broad wavelength band (480-1020 nm). By thermally tuning the phase state of the GST layer, we can dramatically enlarge the working bandwidth of the metamaterial absorber by shifting one absorption peak by about 470 nm. These findings may stimulate many potential applications in, for example, solar cells, energy harvesting, smart sensing/imaging, and color printing.