Metal-organic frameworks (MOFs) comprising metal ions or clusters coordinated to organic ligands have become a class of emerging materials in the field of biomedical research due to their bespoke ...compositions, highly porous nanostructures, large surface areas, good biocompatibility, etc. So far, many MOFs have been developed for imaging and therapy purposes. The unique porous nanostructures render it possible to adsorb and store various substances, especially for gaseous molecules, which is rather challenging for other types of delivery vectors. In this review, we mainly focus on the recent development of MOFs for controlled release of three gaseous transmitters, namely, nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H
S). Although these gaseous molecules have been known as air pollutants for a long time, much evidence has been uncovered regarding their important physiological functions as signaling molecules. These signaling molecules could be either physically absorbed onto or covalently linked to MOFs, allowing for the release of loaded signaling molecules in a spontaneous or controlled manner. We highlight the designing concept by selective examples and display their potential applications in many fields such as cancer therapy, wound healing, and anti-inflammation. We hope more effort could be devoted to this emerging fields to develop signaling molecule-releasing MOFs with practical applications.
We report on the fabrication of a new type of polymeric fluorescent Hg2+ probe covering a broad effective concentration range from nanomolar to micromolar levels and exhibiting considerably enhanced ...detection selectivity. Two amphiphilic diblock copolymers colabeled with Hg2+-reactive caged dye (RhBHA) and Hg2+-catalyzed caged fluorophore (HCMA) in the hydrophilic segments, PS-b-P(DMA-co-HCMA) and PS-b-P(DMA-co-RhBHA), were synthesized via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization, where PS, DMA, HCMA, and RhBHA are polystyrene, N,N-dimethylacrylamide, hydrazone-caged coumarin, and rhodamine B (RhB) derivatives, respectively. The two amphiphilic diblock copolymers can spontaneously self-assemble into mixed micelles in aqueous solution possessing hydrophobic PS cores and HCMA and RhBHA moieties colabeled hydrophilic PDMA coronas. Fluorescence emissions of caged RhBHA and HCMA moieties can effectively turn on in the presence of low and high Hg2+ concentrations via Hg2+-induced ring-opening reaction and Hg2+-catalyzed hydrolysis mechanisms, respectively. The drastically different, but self-complementary reaction kinetics and optimum working concentration ranges of RhBHA and HCMA moieties endow the sensing system with high selectivity and broad sensing concentration range (from nanomolar to micromolar). In addition, the Hg2+-sensing platform can be further employed for the fluorescent ratiometric detection of Cu2+ ion via its selective quenching of the emission of acyclic RhBHA moieties. This work presents a new example of ensembling two partially selective chemical reaction-based fluorometric sensing motifs to achieve enhanced metal ion sensing selectivity and broadened working concentration ranges, which can be further generalized for the construction of other highly selective and broad dynamic range sensing systems.
Over the past decade, a proliferation of research has used nanoparticles to deliver gaseous signaling molecules for medical purposes. The discovery and revelation of the role of gaseous signaling ...molecules have been accompanied by nanoparticle therapies for their local delivery. While most of them have been applied in oncology, recent advances have demonstrated their considerable potential in diagnosing and treating orthopedic diseases. Three of the currently recognized gaseous signaling molecules, nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H
S), are highlighted in this review along with their distinctive biological functions and roles in orthopedic diseases. Moreover, this review summarizes the progress in therapeutic development over the past ten years with a deeper discussion of unresolved issues and potential clinical applications.
Understanding regional environmental heterogeneity (EH) and biodiversity relationships (heterogeneity-diversity relationships: HDRs) is the first step toward coupling environmental variables with ...biodiversity surrogates into regional systematic conservation planning. However, there is no universal method for determining regional HDRs that considers various environmental variables and biodiversity in different regions. This study selected 32 nature reserves as natural areas in Yunnan, China, to examine regional HDRs in Yunnan. We calculated 17 EH parameters (of soil, topography, and climate) and three (ecosystem, plant, and animal) biodiversity indices in the nature reserves. By examining the explanatory power of each EH parameter and area of the nature reserve, we identified the primary parameters and constructed an optimal model for each biodiversity index. The explanatory powers of these parameters varied for each biodiversity index, and those of climatic parameters were generally higher than soil and topographic heterogeneity ones. Heterogeneity of the temperature annual range, followed by area and heterogeneity of soil type, were important parameters for ecosystem diversity of Yunnan and the optimal model explained 56.9%. Plant diversity was explained 54.5% by its optimal model, consisting of heterogeneity of precipitation of the coldest quarter and annual precipitation. Heterogeneity of temperature annual range was important for animal diversity in Yunnan and explained 29.6% of its optimal model. This study suggests that EH parameters can be an effective surrogate for biodiversity, therefore, we suggested that the significance and role of climatically heterogeneous regions for the conservation of biodiversity in Yunnan should be further studied in the future.
Casualty prediction is meaningful to the emergency management of both natural hazards and human-induced disasters. In this study, to predict the number of casualties under emergencies, a two-step ...machine learning method including classification step and regression step is proposed. In the classification step, whether there are casualties under an incident is firstly predicted, then in the regression step, samples predicted to have casualties are used to further predict the exact number of the casualties. Using an open-source dataset, this two-step method is validated. The results show that the two-step model presents better performance than the original regression models. Back propagation neural network combined with Random Forest performs the best in term of both the death toll and the number of injuries. Among all the two-step models, the lowest Mean Absolute Error (MAE) for the death toll is 1.67 while that for the number of injuries is 4.13, which indicates that this method can accurately predict the number of casualties under emergencies. Results of this study is expected to provide support for decision-making on rapid resource allocation and other emergency responses.
Given their relevance in various physiological and pathophysiological mechanisms, gaseous signaling molecules (GSMs), such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S), are ...promising therapeutics for derailing various diseases at precisely controlled concentrations. However, the delivery and release of GSMs have been challenged by the heterogeneity of biological systems. Carefully constructed hybrid materials have exhibited enhanced functional ability owing to the adjusted individual characteristics. In this minireview, we surveyed the mechanisms of gas therapy, recent exceptional studies on the controlled release of GSMs from hybrid nanoplatforms, and their applications in the treatment of various diseases. Single gas therapies and their combined modalities with conventional treatments such as chemotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), and immunotherapy have been summarized, with critical analysis of the contribution of the metallic elements in the various nanoplatforms. Moreover, the challenges and prospects of hybrid GSM releasers as promising healings have been discussed.
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Core cross‐linked (CCL) polymeric micelles covalently labeled with DOTA(Gd) and green‐ emitting NBD fluorophores within pH‐responsive cores are fabricated, which can serve as a dual‐modality ...MR/fluorescence imaging system and exhibit mildly acidic pH‐triggered turn‐on or enhancement of signal intensities for both imaging modalities. Compared to non‐crosslinked diblock precursor, CCL micelles demonstrate better MR and fluorescence imaging performance due to structural stability and integrity endowed by the core cross‐linking procedure. Furthermore, selective enhancement of MR/fluorescence imaging signal intensities of the dual‐modality imaging system can also be actuated under specific intracellular microenvironments such as mildly acidic organelles.
The fabrication of a core cross‐linked (CCL) polymeric micelle‐based dualmodality MR/fluorescence imaging system is reported exhibiting mildly acidic pH‐triggered turn on and enhancement of signal intensities for both imaging modalities.
•Our soil database quantitatively assessed soil productivity in a mountainous region.•Higher productivity soils generally occur in forest areas, lower productivity soils tend to occur at low or ...extremely high elevations.•Conversion of forest or grassland to dry farmland may degrade soil productivity.•Yunnan's western sub-region has high potential for agricultural development.
Mountainous regions are more susceptible to food insecurity because of the shortage of farmland and the conflict between population and cultivated land resources. Here, we focused on the Yunnan province, a typical mountainous region in southwest China, where soil productivity plays a key role in agricultural development. The objectives were to assess spatial variation and sustainable utilization of soil productivity in the Yunnan province. We constructed a soil database based on 706 soil profiles collected from China’s second national soil survey, and assessed soil productivity with a soil productivity index model. We found significant differences in the soil productivity indexes among soil types; the indexes ranged from 0.12 to 0.85 and averaged 0.47. Higher productivity soils generally occurred in forest areas within the west and northwest sub-regions of Yunnan, while lower productivity soils tend to be located at low or extremely high elevations. The soil productivity index was lowest for barren land, followed by dry farmland, grassland, paddy fields, horticultural land, and forest lands. We found the productivity index to increase significantly as latitude increased and to vary with altitude at lower elevations. The soil productivity index ranged from 0.32 to 0.61 generally from the southeast sub-region to the northwest sub-region. Conversion of forest land or grassland to dry farmland may seriously degrade soil productivity. Local governments should consider soil productivity conservation practices when seeking to exploit land resources in mountainous areas. Yunnan's western sub-region has high potential for agricultural development. Effective soil remediation measures and soil and water conservation are needed in the central and southeast sub-regions to maintain sustainable soil productivity.
We have comparatively studied the association of cyclic- and linear-poly(N-isopropylacrylamide) (c-PNIPAM and l-PNIPAM) chains with varying chain lengths and end groups in dilute aqueous solutions by ...laser light scattering (LLS) and stopped-flow temperature-jump measurements. Dynamic and static LLS results reveal that the heating leads to a microphase transition. The resultant structures of interchain aggregates depend on the heating rate and the chain topologies. In comparison with l-PNIPAM chains, a slow heating of c-PNIPAM chains in the solution results in stable mesoglobules with a lower average aggregation number, a looser structure, and a smaller average size (∼290 nm). The temperature-jump-induced association of c-PNIPAM chains in the stopped-flow measurement reveals two kinetic growth stages, which were tentatively ascribed to the loose packing of contracted c-PNIPAM chains and further contraction-induced fragmentation of initially packed c-PNIPAM chains due to the lack of interchain entanglements. On the other hand, for l-PNIPAM chains, the intrachain contraction and interchain penetration/entanglement simultaneously occur as the temperature increases, leading to larger and more compact aggregates whose size increases with the solution temperature.
Abstract Recently optoelectronic synapses generating light-driven electrical memories have played a vital role in the neuromorphic computing of visual perception. However, all the optoelectronic ...synapses demonstrate photoelectric conversion. Peripheral circuits are used for contact photocurrent measurement, leading to significant energy consumption and impeding the evolution of optical wireless communication. It is crucial to develop noncontact neuromorphic visual perception based on light-driven photonic memories. Herein, we report all-photonic artificial synapses based on photochromic perovskites. Triggered by ultraviolet and visible light pulses, cesium lead iodide bromine induces a structural disorder. Optical transmittance changes induced by the disorder last after the pulses are gone. Next, the photonic memories are propagated in the air and processed by a recurrent neural network. The accuracy of binary image recognition is instantly stabilized at 1.0, and accuracy above 0.8 after 7 epochs is achieved in the recognition of digitals from 0 to 9. The all-photonic synapses realize remote perception with zero in-situ energy consumption and enable artificial sensory systems with low-power computation, remote control, and ultrahigh propagation speed.
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