Improving wheelchair user sitting posture to alleviate lumbar fatigue: a study utilizing sEMG and pressure sensors.

Background: The wheelchair is a widely used rehabilitation device, which is indispensable for people with limited mobility. In the process of using a wheelchair, they often face the situation of sitting for a long time, which is easy to cause fatigue of the waist muscles of the user. Therefore, this paper hopes to provide more scientific guidance and suggestions for the daily use of wheelchairs by studying the relationship between the development of muscle fatigue and sitting posture. Methods: First, we collected surface Electromyography (sEMG) of human vertical spine muscle and analyzed it in the frequency domain. The obtained Mean Power Frequency (MPF) was used as the dependent variable. Then, the pose information of the human body, including the percentage of pressure points, span, and center of mass as independent variables, was collected by the array of thin film pressure sensors, and analyzed by a multivariate nonlinear regression model. Results: When the centroid row coordinate of the cushion pressure point is about 16(range, 7.7-16.9), the cushion pressure area percentage is about 80%(range, 70.8%-89.7%), and the cushion pressure span range is about 27(range, 25-31), the backrest pressure point centroid row coordinate is about 15(range, 9.1-18.2), the backrest pressure area percentage is about 35%(range, 11.8%-38.7%), and the backrest pressure span range is about 16(range, 9-22). At this time, the MPF value of the subjects decreased by a small percentage, and the fatigue development of the muscles was slower. In addition, the pressure area percentage at the seat cushion is a more sensitive independent variable, too large or too small pressure area percentage will easily cause lumbar muscle fatigue. Conclusion: The results show that people should sit in the middle and back of the seat cushion when riding the wheelchair, so that the Angle of the hip joint can be in a natural state, and the thigh should fully contact the seat cushion to avoid the weight of the body concentrated on the buttocks; The back should be fully in contact with the back of the wheelchair to reduce the burden on the waist, and the spine posture can be adjusted appropriately according to personal habits, but it is necessary to avoid maintaining a chest sitting position for a long time, which will cause the lumbar spine to be in an unnatural physiological Angle and easily lead to fatigue of the waist muscles.

Molecular Insights into the Dual Promotion-Inhibition Effects of NaCl at Various Concentrations on the CO2 Hydrate Growth: A Molecular Simulation Study.

Hydrate-based CO2 storage in the ocean is considered a potential method for mitigating the greenhouse effect. Numerous studies demonstrated that NaCl exhibited the dual effects of promotion and inhibition in the nucleation and growth processes of CO2 hydrate, whose mechanisms remain unclear. In this study, the effects of NaCl at various concentrations on the CO2 hydrate growth and crystal are investigated. The independent gradient model based on Hirshfeld partition, electrostatic potential, and binding energy is conducted to study the interaction between ions and water molecules. The motion trajectories of ions are observed at the molecular level to reflect the impact of ion motion on hydrate growth. The results show that the influence of NaCl on hydrate growth depends on a delicate balance of dual promotion-inhibition effects. NaCl can combine more water molecules and provide a transport channel of CO2 to promote hydrate growth at low concentrations. Meanwhile, the promoting effects shift toward inhibition with increasing NaCl concentrations. In a word, this paper proposes a novel mechanism for the dual promotion-inhibition effects of NaCl on hydrate growth, which is significant for further research on hydrate-based CO2 storage in the ocean.

One-Step Synthesis of Polyethyleneimine-Grafted Styrene-Maleic Anhydride Copolymer Adsorbents for Effective Adsorption of Anionic Dyes.

Wastewater containing organic dyes has become one of the important challenges in water treatment due to its high salt content and resistance to natural degradation. In this work, a novelty adsorbent, PEI-SMA, was prepared by grafting polyethyleneimine (PEI) onto styrene-maleic anhydride copolymer (SMA) through an amidation reaction. The various factors, such as pH, adsorbent dosage, contact time, dye concentration, and temperature, which may affect the adsorption of PEI-SMA for Reactive Black 5 (RB5), were systematically investigated by static adsorption experiments. The adsorption process of PEI-SMA for RB5 was more consistent with the Langmuir isotherm model and the pseudo-second-order model, suggesting a single-layer chemisorption. PEI-SMA exhibits excellent adsorption performance for RB5 dye, with a maximum adsorption capacity of 1749.19 mg g-1 at pH = 2. Additionally, PEI-SMA exhibited highly efficient RB5 competitive adsorption against coexisting Cl- and SO42- ions and cationic dyes. The adsorption mechanism was explored, and it can be explained as the synergistic effect of electrostatic interaction, hydrogen bonding and π-π interaction. This study demonstrates that PEI-SMA could act as a high performance and promising candidate for the effective adsorption of anionic dyes from aqueous solutions.

Assessing cell viability with dynamic optical coherence microscopy.

Assessing cell viability is important in many fields of research. Current optical methods to assess cell viability typically involve fluorescent dyes, which are often less reliable and have poor permeability in primary tissues. Dynamic optical coherence microscopy (dOCM) is an emerging tool that provides label-free contrast reflecting changes in cellular metabolism. In this work, we compare the live contrast obtained from dOCM to viability dyes, and for the first time to our knowledge, demonstrate that dOCM can distinguish live cells from dead cells in murine syngeneic tumors. We further demonstrate a strong correlation between dOCM live contrast and optical redox ratio by metabolic imaging in primary mouse liver tissue. The dOCM technique opens a new avenue to apply label-free imaging to assess the effects of immuno-oncology agents, targeted therapies, chemotherapy, and cell therapies using live tumor tissues.

Hybrid Grid Pattern Star Identification Algorithm Based on Multi-Calibration Star Verification.

In order to solve the star identification problem in the lost space mode for scientific cameras with small fields of view and higher instruction magnitudes, this paper proposes a star identification algorithm based on a hybrid grid pattern. The application of a hybrid pattern generated by multi-calibration stars in the initial matching enables the position distribution features of neighboring stars around the main star to be more comprehensively described and avoids the interference of position noise and magnitude noise as much as possible. Moreover, calibration star filtering is adopted to eliminate incorrect candidates and pick the true matched navigation star from candidate stars in the initial match. Then, the reference star image is utilized to efficiently verify and determine the final identification results of the algorithm via the nearest principle. The performance of the proposed algorithm in simulation experiments shows that, when the position noise is 2 pixels, the identification rate of the algorithm is 96.43%, which is higher than that of the optimized grid algorithm by 2.21% and the grid algorithm by 4.05%; when the magnitude noise is 0.3 mag, the star identification rate of the algorithm is 96.45%, which is superior to the optimized grid algorithm by 2.03% and to the grid algorithm by 3.82%. In addition, in the actual star image test, star magnitude values of ≤12 mag can be successfully identified using the proposed algorithm.

A novel electrospun polylactic acid silkworm fibroin mesh for abdominal wall hernia repair.

Objective: Abdominal wall hernias are common abdominal diseases, and effective hernia repair is challenging. In clinical practice, synthetic meshes are widely applied for repairing abdominal wall hernias. However, postoperative complications, such as inflammation and adhesion, are prevalent. Although biological meshes can solve this problem to a certain extent, they face the problems of heterogeneity, rapid degradation rate, ordinary mechanical properties, and high-cost. Here, a novel electrospinning mesh composed of polylactic acid and silk fibroin (PLA-SF) for repairing abdominal wall hernias was manufactured with good physical properties, biocompatibility and low production cost. Materials and methods: FTIR and EDS were used to demonstrate that the PLA-SF mesh was successfully synthesized. The physicochemical properties of PLA-SF were detected by swelling experiments and in vitro degradation experiments. The water contact angle reflected the hydrophilicity, and the stress‒strain curve reflected the mechanical properties. A rat abdominal wall hernia model was established to observe degradation, adhesion, and inflammation in vivo. In vitro cell mesh culture experiments were used to detect cytocompatibility and search for affected biochemical pathways. Results: The PLA-SF mesh was successfully synthesized and did not swell or degrade over time in vitro. It had a high hydrophilicity and strength. The PLA-SF mesh significantly reduced abdominal inflammation and inhibited adhesion formation in rat models. The in vitro degradation rate of the PLA-SF mesh was slower than that of tissue remodeling. Coculture experiments suggested that the PLA-SF mesh reduced the expression of inflammatory factors secreted by fibroblasts and promoted fibroblast proliferation through the TGF-ß1/Smad pathway. Conclusion: The PLA-SF mesh had excellent physicochemical properties and biocompatibility, promoted hernia repair of the rat abdominal wall, and reduced postoperative inflammation and adhesion. It is a promising mesh and has potential for clinical application.

Biogeographic patterns of meio- and micro-eukaryotic communities in dam-induced river-reservoir systems.

Although the Three Gorges Dam (TGD) is the world's largest hydroelectric dam, little is known about the spatial-temporal patterns and community assembly mechanisms of meio- and micro-eukaryotes and its two subtaxa (zooplankton and zoobenthos). This knowledge gap is particularly evident across various habitats and during different water-level periods, primarily arising from the annual regular dam regulation. To address this inquiry, we employed mitochondrial cytochrome c oxidase I (COI) gene-based environmental DNA (eDNA) metabarcoding technology to systematically analyze the biogeographic pattern of the three communities within the Three Gorges Reservoir (TGR). Our findings reveal distinct spatiotemporal characteristics and complementary patterns in the distribution of meio- and micro-eukaryotes. The three communities showed similar biogeographic patterns and assembly processes. Notably, the diversity of these three taxa gradually decreased along the river. Their communities were less shaped by stochastic processes, which gradually decreased along the longitudinal riverine-transition-lacustrine gradient. Hence, deterministic factors, such as seasonality, environmental, and spatial variables, along with species interactions, likely play a pivotal role in shaping these communities. Environmental factors primarily drive seasonal variations in these communities, while hydrological conditions, represented as spatial distance, predominantly influence spatial variations. These three communities followed the distance-decay pattern. In winter, compared to summer, both the decay and species interrelationships are more pronounced. Taken together, this study offers fresh insights into the composition and diversity patterns of meio- and micro-eukaryotes at the spatial-temporal level. It also uncovers the mechanisms behind community assembly in various environmental niches within the dam-induced river-reservoir systems. KEY POINTS: • Distribution and diversity of meio- and micro-eukaryotes exhibit distinct spatiotemporal patterns in the TGR. • Contribution of stochastic processes in community assembly gradually decreases along the river. • Deterministic factors and species interactions shape meio- and micro-eukaryotic community.

Sustainable Utilization of Surfactant-Free Microemulsion Regulated by CO2 for Treating Oily Wastes: A Interpretation of the Response Mechanism.

Surfactant-free microemulsions (SFMEs) have been explored extensively to avoid the residual surfactant problem caused by traditional surfactant microemulsions. Many researchers focused on the SFMEs with tertiary amine, which exhibited the typical CO2 response behavior. In this study, the phase diagram of the SFMEs consisting of tripropylamine (TPA), ethanol, and water was readily prepared via the measurements of electrical conductivity. The CO2 response behavior of SFME was confirmed by determination of conductivity and measurement of the average diameter of SFME, which was mainly dependent on the protonation of TPA induced by the additional CO2. The transition of protonated TPA to a more hydrophilic nature from lipophilicity to hydrophilicity should be responsible for the variation of SFME average diameter. In addition, the SFMEs exhibited remarkable solubilizing capacity of crude oil, and three types of SFMEs achieved more than 80% oil removal rate in the washing process of oil sands. It was noted that both oil-in-water and bicontinuous SFMEs could be circularly utilized at least three times with a relatively high oil removal rate (%). Our work provided the insight perspective on the mechanism of SFMEs with a CO2 response behavior.

Controllable Spin-Orbit Torque Induced by Interfacial Ion Absorption in Ta/CoFeB/MgO Multilayers with Canted Magnetizations.

Electrically generated spin-orbit torque (SOT) has emerged as a powerful pathway to control magnetization for spintronic applications including memory, logic, and neurocomputing. However, the requirement of external magnetic fields, together with the ultrahigh current density, is the main obstacle for practical SOT devices. In this paper, we report that the field-free SOT-driven magnetization switching can be successfully realized by interfacial ion absorption in perpendicular Ta/CoFeB/MgO multilayers. Besides, the tunable SOT efficiency exhibits a strong dependence on interfacial Ti insertion thicknesses. Polarized neutron reflection measurements demonstrate the existence of canted magnetization with Ti inserted, which leads to deterministic magnetization switching. In addition, interfacial characterization and first-principles calculations reveal that B absorption by the Ti layer is the main cause behind the enhanced interfacial transparency, which determines the tunable SOT efficiency. Our findings highlight an attractive scheme to a purely electric control spin configuration, enabling innovative designs for SOT-based spintronics via interfacial engineering.

Supervised machine learning improves general applicability of eDNA metabarcoding for reservoir health monitoring.

Effective and standardized monitoring methodologies are vital for successful reservoir restoration and management. Environmental DNA (eDNA) metabarcoding sequencing offers a promising alternative for biomonitoring and can overcome many limitations of traditional morphological bioassessment. Recent attempts have even shown that supervised machine learning (SML) can directly infer biotic indices (BI) from eDNA metabarcoding data, bypassing the cumbersome calculation process of BI regardless of the taxonomic assignment of eDNA sequences. However, questions surrounding the general applicability of this taxonomy-free approach to monitoring reservoir health remain unclear, including model stability, feature selection, algorithm choice, and multi-season biomonitoring. Here, we firstly developed a novel biological integrity index (Me-IBI) that integrates multitrophic interactions and environmental information, based on taxonomy-assigned eDNA metabarcoding data. The Me-IBI can better distinguish the actual health status of the Three Gorges Reservoir (TGR) than physicochemical assessments and have a clear response to human activity. Then, taking this reliable Me-IBI as a supervised label, we compared the impact of selecting different numbers of features and SML algorithms on the stability and predictive performance of the model for predicting ecological conditions in multiple seasons using taxonomy-free eDNA metabarcoding data. We discovered that even with a small number of features, different SML algorithms can establish a stable model and obtain excellent predictive performance. Finally, we proposed a four-step strategy for standardized routine biomonitoring using SML tools. Our study firstly explores the general applicability problem of the taxonomy-free eDNA-SML approach and establishes a solid foundation for the large-scale and standardized biomonitoring application.

Clusterin Is a Prognostic Biomarker of Lower-Grade Gliomas and Is Associated with Immune Cell Infiltration.

Dysregulation of clusterin (CLU) has been demonstrated in many cancers and has been proposed as a regulator of carcinogenesis. However, the roles of CLU in gliomas remain unclear. The expression of CLU was assessed using TIMER2.0, GEPIA2, and R package 4.2.1 software, leveraging data from TCGA and/or GTEx databases. Survival analysis and Cox regression were employed to investigate the prognostic significance of CLU. Immune infiltration was evaluated utilizing TIMER2.0, ESTIMATE, and CIBERSORT. The findings reveal the dysregulated expression of CLU in many cancers, with a marked increase observed in glioblastoma and lower-grade glioma (LGG). High CLU expression indicated worse survival outcomes and was an independent risk factor for the prognosis in LGG patients. CLU was involved in immune status as evidenced by its strong correlations with immune and stromal scores and the infiltration levels of multiple immune cells. Additionally, CLU was co-expressed with multiple immune-related genes, and high CLU expression was associated with the activation of immune-related pathways, such as binding to the antigen/immunoglobulin receptor and aiding the cytokine and cytokine receptor interaction. In conclusion, CLU appears to play crucial roles in tumor immunity within gliomas, highlighting its potential as a biomarker or target in glioma immunotherapy.

Reciprocal regulation of TWIST1 and OGT determines the decitabine efficacy in MDS/AML.

Chemoresistance poses a significant impediment to effective treatment strategies for myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Our previous study unveiled that oncogene TWIST1 interacted with DNA methyltransferase 3a (DNMT3a) to regulate the decitabine (DAC) resistance in MDS/AML. However, the underlying mechanism of TWIST1 dysregulation in DAC resistance remained enigmatic. Here, we found that O-GlcNAc modification was upregulated in CD34+ cells from MDS/AML patients who do not respond to DAC treatment. Functional study revealed that O-GlcNAcylation could stabilize TWIST1 by impeding its interaction with ubiquitin E3 ligase CBLC. In addition, as one typical transcription factor, TWIST1 could bind to the promoter of O-GlcNAc transferase (OGT) gene and activate its transcription. Collectively, we highlighted the crucial role of the O-GlcNAcylated TWIST1 in the chemoresistance capacity of MDS/AML clonal cells, which may pave the way for the development of a new therapeutic strategy targeting O-GlcNAcylated proteins and reducing the ratio of MDS/AML relapse. Video Abstract.

A regression model combined convolutional neural network and recurrent neural network for electroencephalogram-based cross-subject fatigue detection.

Fatigue, one of the most important factors affecting road safety, has attracted many researchers' attention. Most existing fatigue detection methods are based on feature engineering and classification models. The feature engineering is greatly influenced by researchers' domain knowledge, which will lead to a poor performance in fatigue detection, especially in cross-subject experiment design. In addition, fatigue detection is often simplified as a classification problem of several discrete states. Models based on deep learning can realize automatic feature extraction without the limitation of researcher's domain knowledge. Therefore, this paper proposes a regression model combined convolutional neural network and recurrent neural network for electroencephalogram-based (EEG-based) cross-subject fatigue detection. At the same time, a twofold random-offset zero-overlapping sampling method is proposed to train a bigger model and reduce overfitting. Compared with existing results, the proposed method achieves a much better result of 0.94 correlation coefficient (COR) and 0.09 root mean square error (RMSE) in a within-subject experiment design. What is more, there is no misclassification between awake and drowsy states. For cross-subject experiment design, the COR and RMSE are 0.79 and 0.15, respectively, which are close to the existing within-subject results and better than similar cross-subject results. The cross-subject regression model is very important for fatigue detection application since the fatigue indication is more precise than several discrete states and no model calibration is required for a new user. The twofold random-offset zero-overlapping sampling method can also be used as a reference by other EEG-based deep learning research.

A fluorescent probe based on Cu(II) complex induced catalysis for repetitive detection of cysteine.

Real-time imaging and monitoring of biothiols in living cells are essential for understanding pathophysiological processes. However, the design of the fluorescent probe that has accurate and repeatable real-time monitoring capabilities for these targets is highly challenging. In this study, we prepared a fluorescent sensor, Lc-NBD-Cu(II), which contains a N1, N1, N2-tris-(pyridin-2-ylmethyl) ethane-1,2-diamine as a Cu(II) chelating unit and a 7-nitrobenz-2-oxa-1,3-diazole fluorophore to detect Cysteine (Cys). Emission changes promoted by addition of Cys to this probe are distinctive and correspond to a range of processes including Cys induced loss of Cu(II) from Lc-NBD-Cu(II) to form Lc-NBD, Cu(I) oxidation to reform Cu(II), Cys oxidation to form Cys-Cys, Cu(II) binding to Lc-NBD to reform Lc-NBD-Cu(II), and competitive binding of Cu(II) to Cys-Cys. The study also shows that Lc-NBD-Cu(II) maintains high stability during the sensing process and that it can be utilized over a number of detection cycles. Finally, the findings show that Lc-NBD-Cu(II) can be utilized to repetitively sense Cys in living HeLa cells.

New insights into effects of Kaixin Powder on depression via lipid metabolism related adiponectin signaling pathway.

Objective: To clarify the anti-depressive potential mechanisms of Kaixin Powder (KP), a drug that helps to prevent and treat depression and other mentaldiseases, from genome-wide transcriptome profiling. Methods: Transcriptome and KEGG pathway analysis were conducted on the hippocampus of depressed rats, then the differentially expressed genes were validated and serum concentration of lipid parameters were identified by enzymatic assays. Furthermore, high-fat diets induced depression-like behaviors in Syrian golden hamsters were conducted to verify the predicted molecular mechanisms acquired from the transcriptome analysis. Results: Transcriptome results revealed that the 24 differentially expressed genes (DEGs) in chronic mild stress (CMS) rats could be reversed after two weeks of KP treatment. The mechanisms of KP in treating depression firstly involved the regulation of several pathology modules, including lipid metabolism, synapse function and inflammation. KP could regulate imbalances of lipid homeostasis in high-fat diet induced depressive symptoms. Furthermore, it was validated that cholesterol metabolism dysfunction can be ameliorated by KP, which was correlated with upregulation of the AdipoR1-BDNF (brain-derived neurotrophic factor) co-regulatory pathway. Conclusion: Taken together, our results demonstrated that KP not only alleviates depression via traditional mental illness targets, but it may also simulates the cholesterol metabolism and adiponectin signaling with multi-target characteristics.

Deterministic Magnetization Switching via Tunable Noncollinear Spin Configurations in Canted Magnets.

Spin obit torque (SOT) driven magnetization switching has been used widely for encoding consumption-efficient memory and logic. However, symmetry breaking under a magnetic field is required to realize the deterministic switching in synthetic antiferromagnets with perpendicular magnetic anisotropy (PMA), which limits their potential applications. Herein, we report all electric-controlled magnetization switching in the antiferromagnetic Co/Ir/Co trilayers with vertical magnetic imbalance. Besides, the switching polarity could be reversed by optimizing the Ir thickness. By using the polarized neutron reflection (PNR) measurements, the canted noncollinear spin configuration was observed in Co/Ir/Co trilayers, which results from the competition of magnetic inhomogeneity. In addition, the asymmetric domain walls demonstrated by micromagnetic simulations result from introducing imbalance magnetism, leading to the deterministic magnetization switching in Co/Ir/Co trilayers. Our findings highlight a promising route to electric-controlled magnetism via tunable spin configuration, improve our understanding of physical mechanisms, and significantly promote industrial applications in spintronic devices.

[Advances in methods for detecting plastics biodegradation].

The pollution caused by improper handling of plastics has become a global challenge. In addition to recycling plastics and using biodegradable plastics, an alternative solution is to seek efficient methods for degrading plastics. Among them, the methods of using biodegradable enzymes or microorganisms to treat plastics have attracted increasing attention because of its advantages of mild conditions and no secondary environmental pollution. Developing highly efficient depolymerizing microorganisms/enzymes is the core for plastics biodegradation. However, the current analysis and detection methods cannot meet the requirements for screening efficient plastics biodegraders. It is thus of great significance to develop rapid and accurate analysis methods for screening biodegraders and evaluating biodegradation efficiency. This review summarizes the recent application of various commonly used analytical techniques in plastics biodegradation, including high performance liquid chromatography, infrared spectroscopy, gel permeation chromatography, and determination of zone of clearance, with fluorescence analysis techniques highlighted. This review may facilitate standardizing the characterization and analysis of plastics biodegradation process and developing more efficient methods for screening plastics biodegraders.

Metastatic differentiated thyroid cancer with negative serum stimulated Tg but positive post-therapeutic 131I-SPECT/CT scintigraphy: a single-center retrospective study.

PURPOSE: This study aimed to describe the characteristics of patients with metastatic differentiated thyroid carcinoma (DTC) who had positive 131I-scintigraphy but negative stimulated thyroglobulin (sTg), and to evaluate their short-term response to radioiodine therapy (RAI). METHODS: A total of 2250 consecutive postoperative DTC patients, who underwent RAI treatment from July 2019 to June 2022, were analyzed retrospectively. The target group was defined as stimulated Tg < 2 ng/mL with TgAb < 100 IU/mL but with post-therapeutic 131I-SPECT/CT metastases. The characteristics of these patients were analyzed and the metastatic profiles were compared with TgAb positive or sTg positive ones. A cross-sectional efficacy was evaluated 6-12 months after the RAI therapy and the treatment course until the end of the study was recorded. RESULTS: 105 (4.67%) DTC patients were post-therapeutic 131I-SPECT/CT positive and sTg negative (target group). Metastatic profiles were found significant differences between sTg negative and sTg positive ones (P < 0.001). Excellent response (ER) was achieved in 72.4% of the target group between 6-12 months of cross-sectional efficacy assessment, compared with only 12.8% in sTg positive ones (P < 0.001). The majority of the target group didn't require aggressive treatment in short-term follow-up compared with sTg positive group (P < 0.001). CONCLUSION: The percentage of DTCs with negative sTg but positive post-therapeutic 131I-SPECT/CT was relatively low, but still significant. Moreover, the majority of these patients showed an ER to RAI and may not require the next course of therapy. Long-term follow-up is still necessary to assess recurrence and adapt surveillance in these patients.

Adaptive spectroscopic visible-light optical coherence tomography for clinical retinal oximetry.

BACKGROUND: Retinal oxygen saturation (sO2) provides essential information about the eye's response to pathological changes that can result in vision loss. Visible-light optical coherence tomography (vis-OCT) is a noninvasive tool that has the potential to measure retinal sO2 in a clinical setting. However, its reliability is currently limited by unwanted signals referred to as spectral contaminants (SCs), and a comprehensive strategy to isolate true oxygen-dependent signals from SCs in vis-OCT is lacking. METHODS: We develop an adaptive spectroscopic vis-OCT (ADS-vis-OCT) technique that can adaptively remove SCs and accurately measure sO2 under the unique conditions of each vessel. We also validate the accuracy of ADS-vis-OCT using ex vivo blood phantoms and assess its repeatability in the retina of healthy volunteers. RESULTS: In ex vivo blood phantoms, ADS-vis-OCT agrees with a blood gas machine with only a 1% bias in samples with sO2 ranging from 0% to 100%. In the human retina, the root mean squared error between sO2 values in major arteries measured by ADS-vis-OCT and a pulse oximeter is 2.1% across 18 research participants. Additionally, the standard deviations of repeated ADS-vis-OCT measurements of sO2 values in smaller arteries and veins are 2.5% and 2.3%, respectively. Non-adaptive methods do not achieve comparable repeatabilities from healthy volunteers. CONCLUSIONS: ADS-vis-OCT effectively removes SCs from human images, yielding accurate and repeatable sO2 measurements in retinal arteries and veins with varying diameters. This work could have important implications for the clinical use of vis-OCT to manage eye diseases.

Numerous diseases that cause blindness are associated with disrupted oxygen consumption in the retina, the part of the eye that senses light. This highlights the importance of accurately measuring oxygen consumption in the clinic. To address this challenge, we developed a method to analyze images of the retina which have been collected using visible-light optical coherence tomography, a non-invasive imaging method. Our approach achieves accurate oxygen level measurements in blood samples and in healthy volunteers. With further testing, our approach may prove useful in the clinical management of several diseases that cause blindness, allowing clinicians to more accurately diagnose disease and monitor the health of the eye.

A DNA-engineered metal-organic-framework nanocarrier as a general platform for activatable photodynamic cancer cell ablation.

Activatable photodynamic cancer cell ablation constitutes a promising approach to performing highly effective photodynamic therapy (PDT) with mitigated phototoxicity. Regretfully, so far strategies to fabricate activatable PDT agents are only applicable to a limited number of photosensitizers (PSs). Herein, an activatable photodynamic cancer cell ablation platform that can be adopted for versatile PSs is presented. Thereinto, by engineering an iron(iii) carboxylate-based metal-organic framework (MOF), MIL-101(Fe), with DNA grafted after PS loading, both hydrophilic and hydrophobic PSs can undergo negligible unspecific leakage and significant suppression of photosensitization during delivery. Following the reaction between MIL-101 and H2O2 whose level is greatly increased inside the tumor, MIL-101 is selectively degraded to release the loaded PDT agents and recover their photosensitization, controllably killing cancer cells upon H2O2 activation. Such a strategy assisted by a DNA-functionalized MOF significantly expands the varieties of PSs applicable for activatable PDT.