Low-Field-Driven Superior Energy Storage Effect with Excellent Thermal Stability by Constructing Coexistent Glasses.

In this work, we found that the defreezing coexistent glassy ferroelectric states hold significant potential for achieving superior energy storage performance, especially under low fields, by using phase field simulations and experimental approaches. A remarkable room-temperature energy recoverable storage density Wr exceeding 2.7 J/cm3 with a high efficiency η surpassing 80% under a low electric field of 170 kV/cm was obtained in the x = 6-12% compositions of x[Bi(Mg2/3Nb1/3)O3]-(1-x)[0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3-1%MnO2] (BNBT-BMN) ceramics due to the combination of low Pr and high Pm of the coexistent ferroelectric glasses. Intriguingly, the superior Wr and η of the coexistent state of glasses can also be maintained in a wide temperature range of 293-430 K, indicating the excellent thermal stability of the energy storage behavior. Importantly, the Wr and η of this glass coexistent composition increase upon heating from room temperature to 360 K due to the defreezing process, leading to maximum Wr ∼ 2.9 J/cm3 with high efficiency η ∼ 90% of x = 10% at 360 K. When considering both energy storage behavior and thermal stability under low fields (<250 kV/cm), the BNBT-BMN ceramics outperform nearly all lead-free counterparts available today. Consequently, our work not only expands the research scope of ferroic glasses but also establishes a new paradigm for developing superior lead-free dielectrics suitable for high-temperature energy storage devices.

Accuracy of the Cage Placement in Oblique Lumbar Interbody Fusion and its Effects on the Radiological Outcome in Lumbar Degenerative Disease.

STUDY DESIGN: A retrospective study. OBJECTIVES: This study aimed to check how accurately cages were inserted and how they affected the radiological results in oblique lumbar interbody fusion (OLIF) at L2-L5. METHODS: A total of 137 patients diagnosed with lumbar degenerative disease, 184 intervertebral discs were included. We used a new cage deviation classification system on magnetic resonance imaging (MRI) to determine cage insertion accuracy. Cage deviation angles (CDA) were classified into four groups based on the angle formed by the long axis of the cage and the horizontal axis of the vertebral body. Other radiological parameters on plain radiographs and MRI were compared based on this classification. RESULTS: Among 183 cages, 19 were in zone Ⅰ-Ⅱ (10.32%), 163 were in zone II-III (88.59%), and two were in zone III-IV (1.09%). The median cage deviation was 4.97°. No significant differences (H = 2.479, P = .290 > .05) of CDA were found among different segments. Posterior cage deviation accounted 94.57%. The minimal, mild, moderate, and severe cage deviation was 89 (48.4%), 51 (27.7%), 30 (16.3%), and 14 (7.6%) respectively. No differences in radiological parameter changes were noted among different cage obliquity categories. CONCLUSIONS: Approximately 98.91% of cages were placed in zones I-II and II-III. Most cages deviated posteriorly with CDA ranging minimal to moderate. Minimal to moderate cage deviation did not impact radiological outcomes significantly in OLIF at L2-L5. However, avoiding severe cage deviation is crucial to prevent contralateral traversing nerve root injuries.

Rapid discovery of terpene tailoring enzymes for total biosynthesis.

Twenty oxygenated aristolochene congeners were rapidly synthesised by combining genes from four different fungal pathways in the fungal host organism Aspergillus oryzae. Compounds produced in a single step include the natural product hypoxylan A and an epimer of guignaderemophilane C. A new fungal aromatase was discovered that produces phenols by oxidative demethylation.

Amorphous Poly (Aryl Ether Ketones) Containing Methylene Groups with Excellent Thermal Resistance, Dielectric Properties and Mechanical Performance.

Low-dielectric constant polymers are widely used in various microelectronic materials. With the development of 5G communication technology, there is an urgent need for polymer materials with low dielectric constant at high frequency, good thermal resistance, and mechanical properties. In this study, four novel poly (aryl ether ketone) (PAEK) containing different numbers of methylene groups were synthesized via nucleophilic polycondensation reaction. At 10 GHz, these polymer films exhibit excellent dielectric properties with dielectric constants as low as 2.76. The relationship between the dielectric constant and the number of methylene groups is illustrated by constructing the amorphous accumulation cell model. In addition, methylene groups provided the polymer with favorable mechanical performance, including Young's modulus in the range of 2.17-2.21 GPa, the tensile strength from 82.0 to 88.5 MPa and the elongation at the break achieved 7.94%, respectively. Simultaneously, the polymer maintains good thermal resistance with a glass transition temperature (Tg) reaching 216 °C. The result indicates that the obtained novel PAEK is potentially valuable in the field of high-frequency communications.

Total biosynthesis of fungal tetraketide pyrones.

Fungal tetraketide pyrones possess important and potent bioactivities, but their detailed biosynthetic pathways are unknown and synthetic routes to their production are lengthy. Here we investigated the fungal pathways to the multiforisins and compounds related to islandic acid. Heterologous expression experiments yield high titres of these compounds and pathway intermediates. The results both elucidate the pathway and offer a platform for the total biosynthesis of this class of metabolites.

Degradation of dimethyl phthalate by morphology controlled ß-MnO2 activated peroxymonosulfate: The overlooked roles of high-valent manganese species.

Activated peroxymonosulfate (PMS) processes have emerged as an efficient advanced oxidation process to eliminate refractory organic pollutants in water. This study synthesized a novel spherical manganese oxide catalyst (0.4KBr-ß-MnO2) via a simple KBr-guided approach to activate PMS for degrading dimethyl phthalate (DMP). The 0.4KBr-ß-MnO2/PMS system enhanced DMP degradation under different water quality conditions, exhibiting an ultrahigh and stable catalytic activity, outperforming equivalent quantities of pristine ß-MnO2 by 8.5 times. Mn(V) was the dominant reactive species that was revealed by the generation of methyl phenyl sulfone from methyl phenyl sulfoxide oxidation. The selectivity of Mn(V) was demonstrated by the negligible inhibitory effects of Inorganic anions. Theoretical calculations confirmed that Mn (V) was more prone to attack the CO bond of the side chain of DMP. This study revealed the indispensable roles of high-valent manganese species in DMP degradation by the 0.4KBr-ß-MnO2/PMS system. The findings could provide insight into effective PMS activation by Mn-based catalysts to efficiently degrade pollutants in water via the high-valent manganese species.

Design and synthesis of novel poly (aryl ether ketones) containing trifluoromethyl and trifluoromethoxy groups.

The high-frequency and high-speed communication in the 5 G era puts forward requirements for the dielectric properties of polymers. Introducing fluorine into poly(ary ether ketone) can improve its dielectric properties. In this work, by introducing the fluorine group strategy, we successfully designed and synthesized three novel trifluoromethyl (-CF3) or trifluoromethoxy (-OCF3)-containing bisphenol monomers and their F-substitution PEK-based polymers (PEK-Ins). All these PEK-Ins exhibited good thermal, mechanical and dielectric properties. The T d5% of the three polymers is all higher than 520℃. The free volume fraction of novel polymers increased from 3.75% to 5.72%. Among the three polymers, exhibited the lowest dielectric constant of the films is 2.839, and the dielectric loss is 0.0048, ascribing to the increasing free volume. The Young's modulus of the polymer film is as high as 2.9 GPa and the tensile strength is as high as 84 MPa. PEK-Ins reduced the dielectric constant by introducing a low fluorine content. This study provides a new way to design PEK to synthesize low dielectric constant polymers.

Activation of peroxymonosulfate with cobalt embedded in layered δ-MnO2 for degradation of dimethyl phthalate: Mechanisms, degradation pathway, and DFT calculation.

The sulfate radical-based advanced oxidation processes (SR-AOPs) offer huge potential for the removal of organic pollutants. In this study, Co(II)-intercalated δ-MnO2 (Co-δ-MnO2) catalyst was successfully prepared by a simple cation exchange reaction. The obtained Co-δ-MnO2 exhibited high catalytic performance for the removal of dimethyl phthalate (DMP) under the activation of peroxymonosulfate (PMS), with the degradation efficiency reaching 100% within 6 h. Experiments and theoretical calculations revealed that interlayer Co(II) provided unique active sites in Co-δ-MnO2. In addition, radical and non-radical pathways were confirmed to play a role in Co-δ-MnO2/PMS system. •OH, SO4• ̶, and 1O2 were identified to be the dominating reactive species in Co-δ-MnO2/PMS system. This study provided new insights into the design of catalysts and laid a foundation for developing modifiable layered heterogeneous catalysts.

Comparative analysis of codon usage patterns in chloroplast genomes of ten Epimedium species.

BACKGROUND: The Phenomenon of codon usage bias exists in the genomes of prokaryotes and eukaryotes. The codon usage pattern is affected by environmental factors, base mutation, gene flow and gene expression level, among which natural selection and mutation pressure are the main factors. The study of codon preference is an effective method to analyze the source of evolutionary driving forces in organisms. Epimedium species are perennial herbs with ornamental and medicinal value distributed worldwide. The chloroplast genome is self-replicating and maternally inherited which is usually used to study species evolution, gene expression and genetic transformation. RESULTS: The results suggested that chloroplast genomes of Epimedium species preferred to use codons ending with A/U. 17 common high-frequency codons and 2-6 optimal codons were found in the chloroplast genomes of Epimedium species, respectively. According to the ENc-plot, PR2-plot and neutrality-plot, the formation of codon preference in Epimedium was affected by multiple factors, and natural selection was the dominant factor. By comparing the codon usage frequency with 4 common model organisms, it was found that Arabidopsis thaliana, Populus trichocarpa, and Saccharomyces cerevisiae were suitable exogenous expression receptors. CONCLUSION: The evolutionary driving force in the chloroplast genomes of 10 Epimedium species probably comes from mutation pressure. Our results provide an important theoretical basis for evolutionary analysis and transgenic research of chloroplast genes.

Large Electrocaloric Effect in Nanostructure-Engineered (Bi, Na)TiO3-Based Thin Films.

Although the solid-state cooling technology based on electrocaloric response has been considered a promising refrigeration solution for microdevices, the mediocre dipolar entropy change ΔS impedes its practical applications. In this work, ΔS of a conventional ferroelectric thin film, namely, 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 (BNBT), was greatly improved through engineering the nanodomain structures. The number of zero-field polar states and saturation polarization were greatly increased concomitant with a weakened strength of polar correlation in the thin films, owing to the local stabilization of strongly tetragonally distorted nanoclusters (tetragonality of ∼1.25) by modulating the growth conditions during the thin film deposition process. Consequently, a giant ΔS value of ∼ -48.5 J K-1 kg-1 (corresponding to ΔT = ∼27.3 K) and a wide window of operating temperature (>70 °C) were obtained near room temperature under a moderate electric field of 1330 kV cm-1. Moreover, our engineered BNBT thin film exhibits decent fatigue endurance; i.e., a substantial electrocaloric effect over a broad span of temperature can be sustained after 5 × 107 cyclic loading of the electric field. This work provides a universal design strategy for significantly improving the close-to-room-temperature electrocaloric performance of Bi-based ferroelectric thin films without the need of compositional or architectural complexity.

Ultrahigh Energy Storage Density in Glassy Ferroelectric Thin Films under Low Electric Field.

The current approach to achieving superior energy storage density in dielectrics is to increase their breakdown strength, which often incurs heat generation and unexpected insulation failures, greatly deteriorating the stability and lifetime of devices. Here, a strategy is proposed for enhancing recoverable energy storage density (Wr ) while maintaining a high energy storage efficiency (η) in glassy ferroelectrics by creating super tetragonal (super-T) nanostructures around morphotropic phase boundary (MPB) rather than exploiting the intensely strong electric fields. Accordingly, a giant Wr of ≈86 J cm-3 concomitant with a high η of ≈81% is acquired under a moderate electric field (1.7 MV cm-1 ) in thin films having MPB composition, namely, 0.94(Bi, Na)TiO3 -0.06BaTiO3 (BNBT), where the local super-T polar clusters (tetragonality ≈1.25) are stabilized by interphase strain. To the knowledge of the authors, the Wr of the engineered BNBT thin films represents a new record among all the oxide perovskites under a similar strength of electric field to date. The phase field simulation results ascertain that the improved Wr is attributed to the local strain heterogeneity and the large spontaneous polarization primarily is originated from the super-T polar clusters. The findings in this work present a genuine opportunity to develop ultrahigh-energy-density thin-film capacitors for low-electric-field-driven nano/microelectronics.

Diagnostic and prognostic potential of the novel biomarker nuclear cap binding protein subunit 2 (NCBP2) in colon adenocarcinoma.

Background: Colon adenocarcinoma (COAD) is an incurable malignancy and the third most common tumor worldwide. Advances in biomarkers screening have greatly contributed to explore the new diagnostic and prognostic biomarkers for the early detection and prognostic of COAD. However, the heterogeneity-specific nature of COAD in patients of different cancer stages, different races, genders and age are still the major challenge to clinical treatment. Methods: Gene expression, copy number (CN), and dependency score (DS) data were obtained from the Cancer Cell Line Encyclopedia (CCLE), and linear regression analyses were performed using R language. We conducted receiver operating characteristic (ROC) curve analysis and compared the area under the ROC curve area under the curve (AUC) values to evaluate the sensitivity and specificity of nuclear cap binding protein subunit 2 (NCBP2) for the diagnosis of COAD in The Cancer Genome Atlas (TCGA) database. Survival analysis was performed in the distinct NCBP2 expression groups. In vitro experiments and bioinformatics analysis were used to investigate the molecular mechanisms of NCBP2 in COAD and its biological roles. A Connectivity Map (Cmap) was used to identify potential small molecule targeted drugs for NCBP2 in COAD. Results: Through the linear regression analysis of DS, CN, and gene expression, we determined that NCBP2 met our criteria. The mean AUC of the ROC curve of NCBP2 was 0.940±0.050. Survival analysis showed that high NCBP2 expression was associated with a worse prognosis [hazard ratio (HR) =1.98, P<0.007]. NCBP2 knockdown inhibited COAD cell proliferation and caused G0/G1 phase arrest in COAD cells. Conclusions: NCBP2 was the novel diagnostic and prognostic biomarker of in COAD. Our research had implications for the treatment of colon cancer.

Tuning Phase Transition and Thermochromic Properties of Vanadium Dioxide Thin Films via Cobalt Doping.

Vanadium dioxide (VO2) featuring a distinct thermally triggered phase transition is regarded as the most attractive thermochromic material for smart window applications. However, the high transition temperature (∼67 °C) and moderate luminous transmittance (<50%) of the pristine VO2 circumvent room temperature applications. In this work, epitaxial cobalt-doped VO2 thin films were fabricated to tailor the electric and optical properties on a c-plane sapphire substrate. At the highest doping concentration of 10%, the transition temperature of VO2 is reduced to 44 °C, accompanied by a high luminous transmittance of 79% for single-element Co-doped VO2. The roles of cobalt doping and detailed band variation are fully explained experimentally and by modeling (DFT calculation), respectively. Furthermore, the dramatically increased carrier concentration in cobalt-doped VO2 underscores the promising future of cobalt-doped VO2 unveiled by temperature-dependent Hall effect measurement.

RGB-D Visual SLAM Based on Yolov4-Tiny in Indoor Dynamic Environment.

For a SLAM system operating in a dynamic indoor environment, its position estimation accuracy and visual odometer stability could be reduced because the system can be easily affected by moving obstacles. In this paper, a visual SLAM algorithm based on the Yolov4-Tiny network is proposed. Meanwhile, a dynamic feature point elimination strategy based on the traditional ORBSLAM is proposed. Besides this, to obtain semantic information, object detection is carried out when the feature points of the image are extracted. In addition, the epipolar geometry algorithm and the LK optical flow method are employed to detect dynamic objects. The dynamic feature points are removed in the tracking thread, and only the static feature points are used to estimate the position of the camera. The proposed method is evaluated on the TUM dataset. The experimental results show that, compared with ORB-SLAM2, our algorithm improves the camera position estimation accuracy by 93.35% in a highly dynamic environment. Additionally, the average time needed by our algorithm to process an image frame in the tracking thread is 21.49 ms, achieving real-time performance.

New Degree of Freedom in Determining Superior Piezoelectricity at the Lead-Free Morphotropic Phase Boundary: The Invisible Ferroelectric Crossover.

The morphotropic phase boundary (MPB) in lead-free ferroelectrics, starting from a quadruple point (QP), often displays large piezoelectric responses due to the flattened free-energy profiles. In this work, we found that the QP composition rendering most flattened energy profiles could also exhibit abnormally low piezoelectric constants in Hf-doped BaTiO3. Such an anomaly in the strength of piezoelectricity can be ascribed to the progressive influence of additional strain heterogeneity induced by the substitution of Hf4+ for Ti4+ in BaTiO3, which was overlooked previously. An intermediate level of strain heterogeneity can form an invisible ferroelectric crossover consisting of both micro- and nanodomains, resulting in a large elastic softening and high piezoelectricity. With a further increase in the level of strain heterogeneity, the extinction of regular ferroelectric domain structures and pinned polar dynamics resulted in the feeble piezoelectric outputs near the QP composition. Impressively, a giant d33 of ∼610 pC/N has been accordingly obtained through employing a ferroelectric crossover at off-QP composition in Zr-doped BaTiO3, further underpinning the critical role of uncovered ferroelectric crossover on piezoelectricity along MPB. This work offers another degree of freedom in the design of high-performance eco-friendly piezoelectric ceramics.

Single step zero-thermal-expansion temperature measurement of optical reference cavities.

State-of-the-art laser frequency stability has been pushed to the 10-17 level. The laser reference cavity is typically nested in a multi-layer thermal enclosure to increase vacuum thermal time constant and thermally controlled at the zero-thermal-expansion temperature to reduce the external temperature fluctuation effect. It is rather time consuming to accurately determine the zero-thermal-expansion temperature for a large thermal time constant system. Here we develop a fast method for measuring the zero-thermal-expansion temperature of the cavity by relying on just one single temperature scan. We first develop a theoretical model to predict the performance of the laser locked to the reference cavity, and then construct an evaluation system for verification of the model. The zero-thermal-expansion temperature of a 30-cm cavity is measured to be 4.3±0.5 °C. The fast and high precision method for determining the zero-thermal-expansion temperature will be valuable in improving long-term frequency stabilities of cavity stabilized lasers.

3D Printed Multi-Functional Scaffolds Based on Poly(ε-Caprolactone) and Hydroxyapatite Composites.

3D Printed biodegradable polymeric scaffolds are critical to repair a bone defect, which can provide the individual porous and network microenvironments for cell attachment and bone tissue regeneration. Biodegradable PCL/HA composites were prepared with the blending of poly(ε-caprolactone) (PCL) and hydroxyapatite nanoparticles (HA). Subsequently, the PCL/HA scaffolds were produced by the melting deposition-forming method using PCL/HA composites as the raw materials in this work. Through a serial of in vitro assessments, it was found that the PCL/HA composites possessed good biodegradability, low cell cytotoxicity, and good biocompatibility, which can improve the cell proliferation of osteoblast cells MC3T3-E1. Meanwhile, in vivo experiments were carried out for the rats with skull defects and rabbits with bone defects. It was observed that the PCL/HA scaffolds allowed the adhesion and penetration of bone cells, which enabled the growth of bone cells and bone tissue regeneration. With a composite design to load an anticancer drug (doxorubicin, DOX) and achieve sustained drug release performance, the multifunctional 3D printed PCL/HA/DOX scaffolds can enhance bone repair and be expected to inhibit probably the tumor cells after malignant bone tumor resection. Therefore, this work signifies that PCL/HA composites can be used as the potential biodegradable scaffolds for bone repairing.

Synthesis of Two-Dimensional C-C Bonded Truxene-Based Covalent Organic Frameworks by Irreversible Brønsted Acid-Catalyzed Aldol Cyclotrimerization.

The synthesis of new C-C bonded two-dimensional (2D) covalent organic frameworks (COFs) is highly desirable. Here, a simple but effective synthetic strategy has been developed using an irreversible Brønsted acid-catalyzed aldol cyclotrimerization reaction by virtue of truxene as a linkage. Nonolefin C-C bonded 2D truxene-based covalent organic frameworks (Tru-COFs) were constructed by polymerization of 1,3,5-triindanonebenzene (TDB). The structure formation was confirmed by wide-angle X-ray scattering, Fourier-transform infrared spectroscopy, and solid-state 13C CP/MAS NMR. The results showed that the Tru-COFs were porous (645 m2/g) and chemically stable. Benzyl methylene in conjugated Tru-COFs more effectively produced photoinduced radicals than the model truxene compound. Due to the radical photoresponsiveness, Tru-COFs were efficient catalysts for photocatalytic oxidation of sulfides. We expect that this will provide a new synthetic methodology to obtain C-C bonded functional 2D COFs.

Defect engineering in perovskite oxide thin films.

Perovskite oxide thin films are a category of multifunctional materials that have intriguing electrical, magnetic, and photovoltaic properties that can be harnessed combinatorially in future microelectronic devices. However, the inevitable existence of defects in perovskites, regardless of the materials' processing conditions, plays a significant role in their functional properties, which could be either detrimental or beneficial, depending on the exact chemical nature of these defects. As such, defect engineering is an important research area in perovskite thin films that aims at understanding the chemical nature of the defects, from which the physical properties of materials can be more precisely manipulated. Here, we review the common defects in perovskite oxide thin films, which include point defects, dopants, domains and domain walls. The factors that impact the appearance and existence of defects and the corresponding mechanisms are also discussed. While summarizing our previous work, the state-of-the-art in the field from other groups has also been discussed. Most of the defects exist as defect dipoles that affect the oxidation states of relevant ions and induce anomalous behaviors, such as ferroelectricity in otherwise non-ferroelectric thin films, as well as enhanced electrical conductivity in insulators. Furthermore, the couplings between defect dipoles and other degrees of freedom including epitaxial strains and interfaces also provide new strategies to modulate the functional properties of perovskite thin films. Particularly, the coupling between defects and domain wall motion can be regarded as a universal tool to modulate the electric and magnetic properties of thin films of perovskite oxides. It is our hope that this review could promote defect engineering as a general regulation strategy to embellish the functional properties of perovskite oxide thin films.

An effective method to avoid charge leakage along the surface in voltage response measurement.

The voltage response measurement is a non-destructive method to diagnose the aging condition of insulation and is used extensively. The characteristics about the volume polarization and resistance can be obtained by analyzing the measured decay or return voltage of a charged dielectric, which is important for aging diagnosis. To eliminate the influence of the charges leaking along the sample surface on the voltage response analysis, we present an effective three electrode configuration with a potential guard electrode. The voltage decay results show that adopting electrodes with a potential guard electrode can effectively avoid charge leakage along the sample surface.