Solvation/desolvation induced reversible distortion change and switching between spin crossover and single molecular magnet behaviour in a cobalt(II) complex.

Coexistence and switching between spin-crossover (SCO) and single molecular magnet (SMM) behaviours in one single complex may lead to materials that exhibit bi-stable and stimuli sensitive properties in a wide temperature range and under multiple conditions; unfortunately, the conflict and dilemma in the principle of approaching SCO and SMM molecules make it particularly difficult; at low temperature, low spin (LS) SCO molecules possess highly symmetrical geometry and isotropic spins, which are not suitable for SMM behaviour. Herein, we overcome this issue by using a rationally designed Co(II) mononuclear complex [Co(MeOphterpy)2] (ClO4)2 (1; MeOphterpy = 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine), the magnetic properties of which reversibly respond to desolvation and solvation. The solvated structure reinforced a low distortion of the coordination sphere via hydrogen bonding between ligands and methanol molecules, while in the desolvated structure a methoxy group flipping occurred, increasing the distortion of the coordination sphere and stabilising the HS state at low temperature, which exhibited a field-induced slow magnetic relaxation, resulting in a reversible switching between SCO and SMM properties within one molecule.

Enhancement and sensing applications of ultra-narrow band circular dichroism of the chiral nanopore films based on Bragg reflector.

Narrow-band circular dichroism (CD) has attracted considerable attention in the high-sensitivity detection of chiral molecules and chiral catalysis. However, achieving dynamic adjustment of narrow-band CD signals is challenging. In this study, we introduce a disruption layer (DL) and molybdenum disulfide (MoS2) into an L-shaped chiral nanohole array based on a distributed Bragg reflector (DBR), forming L-shaped chiral nanoholes (LCNAs/DL-DBR/MoS2), and investigate the mechanism of CD signal generation. Simulation results show that LCNAs/DL-DBR/MoS2 generate three narrow-band CD signals in the visible region. Analysis of the near-field electric field maps reveals that the three CD peaks of LCNAs/DL-DBR/MoS2 are caused by three Tamm resonances in the DBR layer. The producing and adjusting mechanisms of the CD signals are achieved by changing the structural parameters and the number of MoS2 layers. Dynamic adjustment of the CD signals of LCNAs/DL-DBR/MoS2 can be achieved by changing the environmental temperature. Furthermore, by altering the refractive index of the environment and the DBR layer, it is demonstrated that LCNAs/DL-DBR/MoS2 has a high-quality factor. Our theoretical simulations aid in the design of UNB chiral devices, opening up new avenues for environmental monitoring and the detection of chiral molecules with exceptional sensitivity.

Magnetic field caused enhanced absorption and circular dichroism of an achiral plasmonic nanostructure.

In this paper, modulation of light-matter interactions by a magnetic field is used to generate circular dichroism (CD) from an achiral plasmonic nanostructure. Theoretical investigations show an increase in light absorption by the nanostructure in the presence of a magnetic field. The achiral nanostructure exhibits CD in external magnetic field parallel to circularly polarized light (CPL) incidence. The CD emergence is caused by modulation of electron motion to reduced/enhanced frequencies under CPL incidence. Compared to previous studies, in this paper the mechanism of CD emergence, and the physical reasoning behind the change in CD due to change in magnetic field direction and intensity, are explained. CD intensity increases with increasing magnetic field intensity, while CD sign changes on magnetic field direction reversal. Varying structural parameters significantly influences CD intensity. This study can be helpful in magneto-optics and in magneto-chiral applications.

Thermally stable proton conductivity from nanodiamond oxide.

Herein, we report nanodiamond oxide (NDOx), obtained from modified Hummers' oxidation of nanodiamond (ND), showing excellent proton conductivity and thermal stability. NDOx possesses hydrophilicity resulting in higher water adsorption and the retention of functional groups at elevated temperatures can be attributed to the high proton conductivity and thermal stability, respectively.

Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks.

Electrochemical energy storage has been a widely discussed application of redox-active metal-organic frameworks (MOFs) in the past 5 years. Although MOFs show outstanding performance in terms of gravimetric or areal capacitance and cyclic stability, unfortunately their electrochemical mechanisms are not well understood in most cases. Traditional spectroscopic techniques, such as X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS), have only provided vague and qualitative information about valence changes of certain elements, and the mechanisms proposed based on such information are often highly disputable. In this article, we report a series of standardized methods, including the fabrication of solid-state electrochemical cells, electrochemistry measurements, the disassembly of cells, the collection of MOF electrochemical intermediates, and physical measurements of the intermediates under the protection of inert gases. By using these methods for quantitatively clarifying the electronic and spin state evolution within a single electrochemical step of redox-active MOFs, one can provide clear insight into the nature of electrochemical energy storage mechanisms not only for MOFs, but also for all other materials with strongly correlated electronic structures.

Characterization of the Difference between Day and Night Temperatures on the Growth, Photosynthesis, and Metabolite Accumulation of Tea Seedlings.

Currently, the effects of the differences between day and night temperatures (DIFs) on tea plant are poorly understood. In order to investigate the influence of DIFs on the growth, photosynthesis, and metabolite accumulation of tea plants, the plants were cultivated under 5 °C (25/20 °C, light/dark), 10 °C (25/15 °C, light/dark), and 15 °C (25/10 °C, light/dark). The results showed that the growth rate of the new shoots decreased with an increase in the DIFs. There was a downward trend in the photosynthesis among the treatments, as evidenced by the lowest net photosynthetic rate and total chlorophyll at a DIF of 15 °C. In addition, the DIFs significantly affected the primary and secondary metabolites. In particular, the 10 °C DIF treatment contained the lowest levels of soluble sugars, tea polyphenols, and catechins but was abundant in caffeine and amino acids, along with high expression levels of theanine synthetase (TS3) and glutamate synthase (GOGAT). Furthermore, the transcriptome data revealed that the differentially expressed genes were enriched in valine, leucine, and isoleucine degradation, flavone/flavonol biosyntheses, flavonoid biosynthesis, etc. Therefore, we concluded that a DIF of 10 °C was suitable for the protected cultivation of tea plants in terms of the growth and the quality of a favorable flavor of tea, which provided a scientific basis for the protected cultivation of tea seedlings.

Graphite-like Charge Storage Mechanism in a 2D π-d Conjugated Metal-Organic Framework Revealed by Stepwise Magnetic Monitoring.

Quasi-two-dimensional (2D) fully π-d conjugated metal-organic frameworks (MOFs) have been widely employed as active materials of secondary batteries; however, the origin of their high charge storage capacity is still unknown. Some reports have proposed a mechanism by assuming the formation of multiple radicals on one organic ligand, although there is no firm evidence for such a mechanism, which would run counter to the resonance theory. In this work, we utilized various magnetometric techniques to monitor the formation and concentration of paramagnetic species during the electrochemical process of 2D π-d conjugated Cu-THQ MOF (THQ = tetrahydroxy-1,4-benzoquinone). The spin concentration of the fully reduced (discharged 1.5 V) electrode was estimated to be around only 0.1 spin-1/2 per CuO4 unit, which is much lower than that of the expected "diradical" form. More interestingly, a significant elevation of the temperature-independent paramagnetic term was simultaneously observed, which indicates the presence of delocalized π electrons in this discharged state. Such results were corroborated by first-principles density functional theory calculations and the electrochemically active density of states, which reveal the microscopic mechanism of the charge storage in the Cu-THQ MOF. Hence, a graphite-like charge storage mechanism, where the π-electron band accepts/donates electrons during the charge/discharge process, was suggested to explain the excessive charge storage of Cu-THQ. This graphite-like charge storage mechanism revealed by magnetic studies can be readily generalized to other π-d conjugated MOFs.

Enhancement and Sensing Application of Ultra-Narrowband Circular Dichroism in the Chiral Nanostructures Based on Monolayer MoS2 and a Distributed Bragg Reflector.

Narrowband circular dichroism (CD) has aroused wide concerns in high-sensitivity detections of chiral molecular and chiral catalysis. Nevertheless, the dynamical adjustment of ultra-narrowband (UNB) CD signals is hard to achieve. In this work, single-layer molybdenum disulfide (MoS2), vanadium dioxide (VO2), and a distributed Bragg reflector (DBR) are introduced into X-shaped chiral nanostructures (XCNs) for overcoming the above challenge. The simulation results show that XCNs can generate four strong UNB CD signals in the near-infrared band, and XCNs/MoS2 can further enhance the UNB CD signals. The full width at half-minimum of UNB CD signals can reach 0.14 nm. The electric field distributions of XCNs/MoS2 show that the four CD signals originate from the coupling between the guided mode resonances along the x and y axes in the VO2 layer and the Tamm plasmon polaritons along the x and y axes in the DBR layer. Four UNB CD peaks can be actively tuned by varying the structural parameters, the number of MoS2 layers, and the environmental temperature. The FOM of XCNs/MoS2 can reach 1487 by changing the refractive index of the DRB layers. These findings contribute to the design of UNB chiral devices and provide new possibilities for environmental monitoring and ultrasensitive detection of chiral molecules.

Enhanced circular dichroism of cantilevered nanostructures by distorted plasmon.

Chiral structures have a wide range of applications, such as biometric identification, chemical analysis, and chiral sensing. The simple fabrication process of chiral nanostructures that can produce a significant circular dichroism (CD) effect remains a challenge. Here, a three-dimensional (3D) cantilever-shaped nanostructure, which inherits the chiral advantages of 3D nanostructures and simplicity of 2D nanostructures, is proposed. The nanostructure can be prepared by the combination of one-time electron beam lithography and oblique-angle deposition and consists of a thin metal film with periodic holes such that two hanging arms were attached to the edges of holes. The length of the cantilever and the height difference between the two arms can be adjusted by controlling the tilt angle of beam current during the deposition processes. Numerical calculations showed that the enhancement of CD signal was achieved by plasmon distortion on the metal film by the lower hanging part of the cantilever structure. Furthermore, signals can be actively adjusted using a temperature-sensitive polydimethylsiloxane (PDMS) material. The angle between the lower cantilever and the top metal film was regulated by the change in PDMS volume with temperature. The results provide a new way to fabricating 3D nanostructures and a new mechanism to enhance the CD signal. The proposed nanostructure may have potential applications, such as in ultra-sensitive detection and remote temperature readout, and is expected to be an ultra-compact detection tool for nanoscale structural and functional information.

Efficacy, safety and predictors of combined fruquintinib with programmed death-1 inhibitors for advanced microsatellite-stable colorectal cancer: A retrospective study.

Background: Research findings have revealed that combining anti-angiogenesis inhibitors with programmed death-1(PD-1) inhibitors can reverse the immunosuppressive tumor microenvironment and enhance the antitumor immune response. To explore the therapeutic options for breaking immune tolerance in microsatellite stability (MSS) or mismatch repair-proficiency (pMMR) advanced colorectal cancer (CRC), we assessed the efficacy, safety and predictors of the fruquintinib and PD-1 inhibitors combination in patients with MSS/pMMR advanced CRC in a real-world environment. Methods: We conducted a single-center retrospective study by collecting relevant data on patients with MSS/pMMR advanced CRC who received fruquintinib coupled with PD-1 inhibitors in the First Affiliated Hospital of Zhengzhou University between August 2019 and November 2021, focusing on progression-free survival. Results: We enrolled 110 eligible patients in this study between August 2019 and November 2021. At the deadline (January 20, 2022), 13 patients had objective responses. The objective response rate was 11.8% (13/110, 95% confidence interval [CI]: 6.4-18.2), the disease control rate was 70.0% (82/110, 95% CI: 60.9-78.2), and the progression-free survival was 5.4 months (95% CI: 4.0-6.8). Liver metastases (hazard ratio [HR]: 0.594, 95% CI: 0.363-0.973, P<0.05), alkaline phosphatase elevation (ALP>160U/L) (HR: 0.478, 95%CI: 0.241-0.948, P<0.05), fibrinogen elevation (FIB>4g/L) (HR: 0.517, 95% CI: 0.313-0.855, P<0.05), and an increase in the ALP level from the baseline after treatment (HR: 1.673, 95% CI: 1.040-2.690, P<0.05) were negative predictors of the progression-free survival. A total of 101 of 110 patients experienced treatment-related adverse events, including 14 who experienced grade 3 or above treatment-related adverse events, and no treatment-related deaths occurred. Hypertension was the most frequently encountered grade 3 treatment-related adverse event. Conclusion: Fruquintinib combined with PD-1 inhibitors has antitumor activity and manageable safety in treating patients with MSS/pMMR advanced CRC. Liver metastases, ALP level and FIB level might be a prediction of the patient response to this therapy.

Hyaluronic Acid-Stabilized Fe3O4 Nanoparticles for Promoting In Vivo Magnetic Resonance Imaging of Tumors.

The use of iron oxide (Fe3O4) nanoparticles as novel contrast agents for magnetic resonance imaging (MRI) has attracted great interest due to their high r 2 relaxivity. However, both poor colloidal stability and lack of effective targeting ability have impeded their further expansion in the clinics. Here, we reported the creation of hyaluronic acid (HA)-stabilized Fe3O4 nanoparticles prepared by a hydrothermal co-precipitation method and followed by electrostatic adsorption of HA onto the nanoparticle surface. The water-soluble HA functions not only as a stabilizer but also as a targeting ligand with high affinity for the CD44 receptor overexpressed in many tumors. The resulting HA-stabilized Fe3O4 nanoparticles have an estimated size of sub-20 nm as observed by transmission electron microscopy (TEM) imaging and exhibited long-term colloidal stability in aqueous solution. We found that the nanoparticles are hemocompatible and cytocompatible under certain concentrations. As verified by quantifying the cellular uptake, the Fe3O4@HA nanoparticles were able to target a model cell line (HeLa cells) overexpressing the CD44 receptor through an active pathway. In addition, we showed that the nanoparticles can be used as effective contrast agents for MRI both in vitro in HeLa cells and in vivo in a xenografted HeLa tumor model in rodents. We believe that our findings shed important light on the use of active targeting ligands to improve the contrast of lesion for tumor-specific MRI in the nano-based diagnosis systems.

A Review of Vision-Laser-Based Civil Infrastructure Inspection and Monitoring.

Structural health and construction security are important problems in civil engineering. Regular infrastructure inspection and monitoring methods are mostly performed manually. Early automatic structural health monitoring techniques were mostly based on contact sensors, which usually are difficult to maintain in complex infrastructure environments. Therefore, non-contact infrastructure inspection and monitoring techniques received increasing interest in recent years, and they are widely used in all aspects of infrastructure life, owing to their convenience and non-destructive properties. This paper provides an overview of vision-based inspection and vision-laser-based monitoring techniques and applications. The inspection part includes image-processing algorithms, object detection, and semantic segmentation. In particular, infrastructure monitoring involves not only visual technologies but also different fusion methods of vision and lasers. Furthermore, the most important challenges for future automatic non-contact inspections and monitoring are discussed and the paper correspondingly concludes with state-of-the-art algorithms and applications to resolve these challenges.

Efficient Excitation and Tuning of Multi-Fano Resonances with High Q-Factor in All-Dielectric Metasurfaces.

Exciting Fano resonance can improve the quality factor (Q-factor) and enhance the light energy utilization rate of optical devices. However, due to the large inherent loss of metals and the limitation of phase matching, traditional optical devices based on surface plasmon resonance cannot obtain a larger Q-factor. In this study, a silicon square-hole nano disk (SHND) array device is proposed and studied numerically. The results show that, by breaking the symmetry of the SHND structure and transforming an ideal bound state in the continuum (BIC) with an infinite Q-factor into a quasi-BIC with a finite Q-factor, three Fano resonances can be realized. The calculation results also show that the three Fano resonances with narrow linewidth can produce significant local electric and magnetic field enhancements: the highest Q-factor value reaches 35,837, and the modulation depth of those Fano resonances can reach almost 100%. Considering these properties, the SHND structure realizes multi-Fano resonances with a high Q-factor, narrow line width, large modulation depth and high near-field enhancement, which could provide a new method for applications such as multi-wavelength communications, lasing, and nonlinear optical devices.

Direct photo-oxidation of methane to methanol over a mono-iron hydroxyl site.

Natural gas, consisting mainly of methane (CH4), has a relatively low energy density at ambient conditions (~36 kJ l-1). Partial oxidation of CH4 to methanol (CH3OH) lifts the energy density to ~17 MJ l-1 and drives the production of numerous chemicals. In nature, this is achieved by methane monooxygenase with di-iron sites, which is extremely challenging to mimic in artificial systems due to the high dissociation energy of the C-H bond in CH4 (439 kJ mol-1) and facile over-oxidation of CH3OH to CO and CO2. Here we report the direct photo-oxidation of CH4 over mono-iron hydroxyl sites immobilized within a metal-organic framework, PMOF-RuFe(OH). Under ambient and flow conditions in the presence of H2O and O2, CH4 is converted to CH3OH with 100% selectivity and a time yield of 8.81 ± 0.34 mmol gcat-1 h-1 (versus 5.05 mmol gcat-1 h-1 for methane monooxygenase). By using operando spectroscopic and modelling techniques, we find that confined mono-iron hydroxyl sites bind CH4 by forming an [Fe-OH···CH4] intermediate, thus lowering the barrier for C-H bond activation. The confinement of mono-iron hydroxyl sites in a porous matrix demonstrates a strategy for C-H bond activation in CH4 to drive the direct photosynthesis of CH3OH.

Foliar Herbivory Reduces Rhizosphere Fungal Diversity and Destabilizes the Co-occurrence Network.

Insect herbivores can adversely impact terrestrial plants throughout ontogeny and across various ecosystems. Simultaneously, the effects of foliar herbivory may extend belowground, to the soil microbial community. However, the responses in terms of the diversity, assembly, and stability of rhizosphere fungi to aboveground herbivory remain understudied. Here, using high-throughput sequencing, the effects of foliar insect herbivory on rhizosphere fungal microbes were investigated in a common garden experiment that manipulated herbivory intensity and time from herbivore removal. The number of observed fungal species was reduced by a greater herbivory intensity, with some species evidently sensitive to herbivory intensity and time since herbivore removal. Rhizofungal assembly processes were altered by both herbivory intensity and time since herbivore removal. Further, we found evidence that both factors strongly influenced fungal community stability: a high intensity of herbivory coupled with a shorter time since herbivore removal resulted in low stability. These results suggest that foliar herbivory can adversely alter fungal diversity and stability, which would in turn be harmful for plant health. Fortunately, the effect seems to gradually diminish with time elapsed after herbivore removal. Our findings provide a fresh, in-depth view into the roles of rhizofungi in enhancing the adaption ability of plants under environmental stress.

Cancer survival prognosis with Deep Bayesian Perturbation Cox Network.

BACKGROUND: The Cox proportional hazards model with neural networks is widely used to accurately predict survival outcome for choosing cancer treatment strategies. Although this method has shown outstanding performance in many tasks, it has encountered challenges when dealing with high-dimensional datasets. In this study, we point out that the Cox network has estimation bias in processing such datasets with a large number of censored samples. The estimation bias is composed of censored estimation bias and variance estimation bias, which limit the prediction performance of the model. In order to correct this bias, this paper proposes the Deep Bayesian Perturbation Cox Network (DBP), which introduces Bayesian prior knowledge about censored samples to optimize the training process of the neural network. Specifically, the model uses a sampling module called Bayesian Perturbation to approximate the prior knowledge, which can be used as a component for other Cox-based neural networks. RESULTS: The comparison between DBP and the previous model in different kinds of genomic datasets demonstrates that our model has made significant improvements over previous state-of-the-art methods. In addition, the simulation experiments are performed to illustrate how the DBP method addresses the bias caused by Cox Network. In the case study, based on the predicted risks in BRCA data from TCGA, we identify 400 differential expressed genes and 20 KEGG pathways that are associated with breast cancer prognosis, among which 65% of the top 20 genes have been proved by literature review. CONCLUSION: Overall, these results demonstrate that our proposed method is advanced and robust in datasets with a large proportion of censored samples. Besides, it can guide to discover disease-related genes.

In PICU acute kidney injury stage 3 or mortality is associated with early excretion of urinary renin.

BACKGROUND: Urinary renin is proposed to be a novel prognostic biomarker of acute kidney injury (AKI) in adults. The intention of our study was to evaluate the early predictive value of urinary renin for AKI and pediatric intensive care unit (PICU) mortality in critically ill children. METHODS: The first available urine sample during the first 24 h after admission was collected upon PICU admission for the measurement of renin using ELISA. Urinary renin concentrations were corrected for urinary creatinine (urinary renin-to-creatinine ratio, uRenCR). AKI was defined based on KDIGO criteria. RESULTS: Of the 207 children, 22 developed AKI, including 6 with stage 1, 6 with stage 2, and 10 with stage 3, and 14 died during PICU stay. There was a significant difference in uRenCR between non-AKI children and those with AKI stage 3 (P = 0.001), but not with AKI stage 1 or 2. The uRenCR remained associated with AKI stage 3 and PICU mortality after adjustment for potential confounders. The area under the receiver operating characteristic curve of uRenCR for discrimination of AKI stage 3 was 0.805, and PICU mortality was 0.801. CONCLUSIONS: Urinary renin was associated with the increased risk for AKI stage 3 and PICU mortality in critically ill children. IMPACT: Urinary renin is proposed to be a novel prognostic biomarker of AKI in adult patients. There are some differences between children and adults in physiological and pathophysiological characteristics. This study demonstrated that urinary renin was associated with the increased risk for AKI stage 3 and PICU mortality in critically ill children. Accurate identification of patients with severe renal injury or at high risk for mortality early in the disease course could augment the efficacy of available interventions and improve patient outcomes.

Improving Semantic Segmentation via Efficient Self-Training.

Starting from the seminal work of Fully Convolutional Networks (FCN), there has been significant progress on semantic segmentation. However, deep learning models often require large amounts of pixelwise annotations to train accurate and robust models. Given the prohibitively expensive annotation cost of segmentation masks, we introduce a self-training framework in this paper to leverage pseudo labels generated from unlabeled data. In order to handle the data imbalance problem of semantic segmentation, we propose a centroid sampling strategy to uniformly select training samples from every class within each epoch. We also introduce a fast training schedule to alleviate the computational burden. This enables us to explore the usage of large amounts of pseudo labels. Our Centroid Sampling based Self-Training framework (CSST) achieves state-of-the-art results on Cityscapes and CamVid datasets. On PASCAL VOC 2012 test set, our models trained with the original train set even outperform the same models trained on the much bigger augmented train set. This indicates the effectiveness of CSST when there are fewer annotations. We also demonstrate promising few-shot generalization capability from Cityscapes to BDD100K and from Cityscapes to Mapillary datasets.

Enhanced circular dichroism of plasmonic chiral system due to indirect coupling of two unaligned nanorods with metal film.

Circular dichroism (CD) demonstrates broad application prospects in enantioselective catalysis, chiral separation, and ultrasensitive detection. Increasing the CD intensity of easily fabricated plasmonic nanostructures will promote the application of these artificial nanostructures. A chiral plasmonic system that consists of two unaligned nanorods and a metal film is proposed in this study to achieve a large CD effect. Indirect coupling of a nanorod-film-nanorod in the proposed chiral plasmonic system generates a larger CD intensity compared to the direct coupling of a nanorod-nanorod. In addition, the effects of structural parameters on the CD effect of the proposed system are numerically investigated. Results showed that the indirect coupling is strongly dependent on the separation between the nanorod and the metal film. The results of this study can provide an effective strategy to enhance the CD effect of plasmonic chiral systems.