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Supramolecular organic framework (SOF) has recently garnered significant research interest in the field of luminescent materials. However, SOF with room‐temperature phosphorescence emission in solution is very rare due to the quenching of dissolved oxygen and free molecular motions, which would lead to nonradiative deactivation of triplet exciton in liquid state. In this work, a 3D cationic phosphorescent SOF is synthesized through host‐guest interaction between CB[8] and a tetrahedral monomer TBBP, which can rapidly adsorb anionic guests in solution. When anionic dyes are introduced, triplet to singlet Förster resonance energy transfer (TS‐FRET) in solution can be achieved, and delayed fluorescence with large Stokes shift can be realized. Additionally, when anionic drugs are introduced, the phosphorescence of TBBP‐CB[8] can be quenched due to charge transfer, enabling the detection of drugs through phosphorescence signals. Taking advantage of the fast adsorption property of 3D SOF, an INHIBIT logic gate with three inputs and two outputs is constructed. These findings provide a novel method to prepare phosphorescent functional materials and a new pathway to construct TS‐FRET system in solution. [ABSTRACT FROM AUTHOR]

[Objective] To quantitatively study the relationship between land use change and ecosystem service value in Sichuan section of the upper reaches of the Yellow River in the past 20 years, and to evaluate the effect of comprehensive ecological management in this section, so as to provided a basis for improving ethnic regional spatial planning, ecological environmental protection and management, and promoted the high-quality development of the Yellow River Basin. [Methods] Using the land use data of the upper reaches of the Yellow River in Sichuan in 2000, 2010 and 2020, land use change was analyzed based on land use dynamic attitude and land use matrix, and the economic value of the ecosystem service value equivalent per unit area of the terrestrial ecosystem in China was revised. The effects of land use change on the ecosystem service value in the upper reaches of the Yellow River from 2000 to 2020 in Sichuan were quantitatively studied. [Results] (1) From 2000 to 2020, the land use area of forest, desert, wetland and water system in the upper reaches of the Yellow River in Sichuan showed an increasing trend, while the land use area of cultivated land, shrub, grassland and glacial and snow in the upper reaches of the Yellow River showed a decreasing trend, and the land use change in 2010-2020 was more significant than that in 2000-2010. (2) The ecosystem service value of the upper reaches of the Yellow River in Sichuan in 2000, 2010 and 2020, was 1.27X1010, 2.51 X1010, 3.92X1010 yuan, respectively, showing an increasing trend. The sensitivity analysis showed that he analysis results were reliable. Among all land use types, grassland made the most significant contribution o total ecosystem value, and the contribution rate of grassland ecological service was 93.90% and 72.90% in 2000-2010 and 2010-2020, respectively, followed by wetland and forest land. (3) In the study area, the value of each individual ecosystem service showed an increasing trend in the past 20 years, and the sub-value of regional ecological service function was regulatory service > support service > supply service > cultural service. Among the 11 individual functions, the significant service value was climate regulation, hydrology regulation, soil conservation and biodiversity. The sum of the four items accounted for more than 69.50% of he total value. Land use change in the upper reaches of the Yellow River in Sichuan affected the changes of regional ecosystem service value, and grassland was the most significant, followed by wetland and forest and. [Conclusion] The results showed that the results of ecological governance in the past 20 years have been gradually enhanced, and the ecological environment has continuously improved. [ABSTRACT FROM AUTHOR]

Background: Accurate estimation of potential evapotranspiration (PET) is the key for studying land-air interaction hydrological processes. Several models are used to estimate the PET based on standardized meteorological data. Although combination-based models have the highest level performance estimation of PET, they require more meteorological data and may therefore be difficult to apply in areas lacking meteorological observation data. Results: The results showed significant differences in the spatial trends of PET calculated by different models in China, the Doorenbots–Pruitts model revealed the highest PET (1902.6 mm), and the Kuzmin model revealed the lowest PET (349.6 mm), with the largest difference being 5.5 times. The Romanenko and the Rohwer models were the recommended temperature-based and aerodynamic-based models. On the other hand, the Abtew model was more suitable for arid and semi-arid regions, while the Priestley–Taylor model was more suitable for humid regions. Combination-based models revealed ideal calculation accuracies, among which the Penman–Monteith model was the best option for PET calculation. Conclusions: The accuracy range of Romanenko, Rohwer, Abten, Priestley Taylor, and Penman Monteith models improved in MPZ and TCZ is higher than that improved in TMZ and SMZ. This does not mean that the improved models have higher accuracy in MPZ and TCZ than in TMZ and SMZ. On the contrary, the original model performed poorly in MPZ and TCZ, so the improved accuracy was relatively large. The unimproved model was already more suitable in TMZ and SMZ, so the improved accuracy was relatively small. Therefore, regional calibration of the PET models can improve the accuracy and applicability of PET calculation, providing a reference for studying hydrological processes in different climatic zones. [ABSTRACT FROM AUTHOR]

The developments of pure organic room-temperature phosphorescence (RTP) materials with circularly polarized luminescence (CPL) have significantly facilitated the future integration and systemization of luminescent material in fundamental science and technological applications. Here, a type of photoinduced circularly polarized RTP materials are constructed by homogeneously dispersing phosphorescent chiral helical substituted polyacetylenes into a processable poly(methyl methacrylate) (PMMA) matrix. These substituted polyacetylenes play vital roles in the propagation of CPL and present prominently optical characteristics with high absorption and luminescent dissymmetric factors up to 0.029 (gabs) and 0.019 (glum). The oxygen consumption properties of the films under UV light irradiation endow materials with dynamic chiro-optical functionality, which can leverage of light to precisely control and manipulate the circularly polarized RTP properties with the remarkable advantages of being contactless, wireless and fatigue-resistant. Significantly, the distinct materials with dynamic properties can be used as anti-counterfeiting materials involving photoprogrammability. 'Pure organic room-temperature phosphorescence (RTP) materials with circularly polarized luminescence (CPL) gained increasing interest. Here, the authors propose a photoinduced circularly polarized RTP material by homogeneously dispersing phosphorescent chiral polyacetylenes into a processable polymer matrix. [ABSTRACT FROM AUTHOR]

Tree water transport and utilization are essential for maintaining ecosystem stability in seasonally arid areas. However, it is not clear how Platycladus orientalis absorbs, consumes via transpiration, and stores water under varying precipitation conditions. Therefore, this study used stem sap flow thermal dissipation probes and hydrogen and oxygen isotope tracing technology to observe different water control treatments in a P. orientalis plantation. We found that the average daily sap flow of P. orientalis under different water control treatments had the following order: no rainfall (NR) < half rainfall (HR) < double rainfall (DR) < natural rainfall (AR). The percentage of nocturnal sap flow was as follows: AR (13.34%) < NR (19.62%) < DR (20.84%) < HR (30.90%). The percentage of water storage was NR (4.13%) < AR (4.49%) < DR (6.75%) < HR (9.29%). The sap flow of P. orientalis was primarily affected by vapor pressure deficit and solar radiation, with a degree of influence of DR < NR < HR < AR. The response of P. orientalis sap flow to environmental factors differed due to the soil changes in relative extractable water (REW) before and after precipitation. During high REW conditions, environmental factors have a higher impact on sap flow. The source of water absorbed changed regularly with the precipitation gradient. When soil water content increased, the water source used by P. orientalis gradually changed to shallow soil. Compared to before and after precipitation, there was no significant change except for NR. P. orientalis could regularly adjust the activities of transpiration water consumption, water storage, and absorption. This adaptive property is conducive to survival through extreme drought stress. [ABSTRACT FROM AUTHOR]

In this work, a universal strategy for solid, solution, or gel state organic persistent luminescent materials via radiative energy transfer is proposed. The persistent luminescence (τ>0.7 s) could be remotely regulated between different colors by controlling the isomerization of the energy acceptor. The function relies on the simple radiative energy transfer (reabsorption) mechanism, rather than the complicated communication between the excited state of the molecules such as Förster resonance energy transfer or Dexter energy transfer. And the "apparent lifetime" for the energy acceptor is the same as the lifetime of the energy donor, which was different with a traditional radiative energy transfer process. The simple working principle endows this strategy with huge universality, flexibility, and operability. This work offers a simple, feasible, and universal way to construct various persistent luminescent materials in solid, solution, and gel states. [ABSTRACT FROM AUTHOR]

In this work, a universal strategy for solid, solution, or gel state organic persistent luminescent materials via radiative energy transfer is proposed. The persistent luminescence (τ>0.7 s) could be remotely regulated between different colors by controlling the isomerization of the energy acceptor. The function relies on the simple radiative energy transfer (reabsorption) mechanism, rather than the complicated communication between the excited state of the molecules such as Förster resonance energy transfer or Dexter energy transfer. And the "apparent lifetime" for the energy acceptor is the same as the lifetime of the energy donor, which was different with a traditional radiative energy transfer process. The simple working principle endows this strategy with huge universality, flexibility, and operability. This work offers a simple, feasible, and universal way to construct various persistent luminescent materials in solid, solution, and gel states. [ABSTRACT FROM AUTHOR]

Amorphous room-temperature phosphorescent (RTP) materials based on the copolymerization strategy have been widely recognized for their high efficiency, low cost and ease of preparation. However, the RTP efficiency of polyacrylamide copolymers is severely affected by water and oxygen. A further treatment is needed to stabilize the RTP properties of copolymer materials. This study introduces a facile secondary processing strategy using water molecules as a hydrogen bridge to synergetically suppress the non-radiative transition of triplet excitons. Both the RTP lifetime and quantum yield are stabilized and significantly improved, which expands the application field of polyacrylamide copolymer RTP materials. [ABSTRACT FROM AUTHOR]

Featuring simultaneous multicolor imaging for multiple targets, a synergistic strategy has become promising for fluorescence imaging applications. Visible and first near infrared (NIR-I, 700–900 nm) fluorophores have been explored for multicolor imaging to achieve good multi-target capacity, but they are largely hampered by the narrow imaging bands available (400–900 nm, bandwidth 500 nm), the broad emission spectra of many fluorophores, shallow tissue penetration and scattering loss. With attractive characteristic emission peaks in the second NIR window (NIR-II, 1000–1700 nm), a narrow emission spectrum, and deeper tissue penetration capability, rare-earth doped nanoparticles (RENPs) have been considered by us to be outstanding candidates for multicolor bioimaging. Herein, two RENPs, NaYF4:Yb20Er2@NaYF4 and NaYF4:Nd5@NaYF4, were prepared and modified with polyethylene glycol (PEG) to explore simultaneous imaging in the NIR-IIb (1530 nm, under 980 nm laser excitation) and the NIR-II (1060 nm, under 808 nm laser excitation) windows. The PEGylated-RENPs (RENPs@PEG) were able to simultaneously visualize the circulatory system, trace the lymphatic system, and evaluate the skeletal system. Our study demonstrates that RENPs have high synergistic imaging capability in multifunctional biomedical applications using their NIR-II fluorescence. Importantly, the two RENPs@PEG are complementary to each other for higher temporal resolution in NaYF4:Nd5@NaYF4@PEG and higher spatial resolution in NaYF4:Yb20Er2@NaYF4@PEG, which may provide more comprehensive and accurate imaging diagnosis. In conclusion, RENPs are highly promising nanomaterials for multicolor imaging in the NIR-II window. [ABSTRACT FROM AUTHOR]

Pure organic room-temperature phosphorescent (RTP) materials have been attracting widespread attention due to the unique properties and broad applications. However, RTP materials with the adjustable photochromic property are still a challenge. Based on this, two polymers containing hexaarylbiimidazole are strategically designed with dual emission of both fluorescence and phosphorescence. Furthermore, both polymers show sensitive photochromic responses from faint yellow to brown upon exposure to ultraviolet light. This study can enrich pure organic luminescent systems and provide new ideas for functional RTP materials. [ABSTRACT FROM AUTHOR]

Recently, a remarkable advance has been made for metal‐free room‐temperature phosphorescence (RTP) crystals with high phosphorescence quantum yield. However, amorphous, especially heavy‐atom‐free, RTP materials still suffer from low quantum yield due to the transition‐forbidden character of phosphorescence and the relatively poor suppression of nonradiative transition in amorphous materials. In this study, a series of single‐benzene structure‐based high intersystem crossing yield phosphor is obtained. After embedding into polyvinyl alcohol matrix, all these phosphor exhibits efficient phosphorescence emission (ФP, up to 44.0%). Besides, photo‐switchable phosphorescence emission can be obtained by doping these molecules into a polymethyl methacrylate (PMMA) matrix. The phosphorescence can be gradually switched on by consuming the residual oxygen in the PMMA matrix under continuous UV light irradiation. Furthermore, the phosphorescence will be spontaneously switched off under ambient conditions. Taking advantage of the photoactivation character, this material has potential in information storage and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

In the field of intelligent luminescence materials, it is a great challenge to regulate organic room-temperature phosphorescence by light irradiation. Herein, benzothiadiazole was modified with viologen derivatives and copolymerized to achieve amorphous RTP emission. The photo-stimulated color change in both emission and absorption has a good reversibility after cycles of light irradiation. [ABSTRACT FROM AUTHOR]

Background: Apolipoprotein E4 (apoE4) is a major genetic risk factor of Alzheimer's disease. Its C-terminal-truncated apoE4 (Δ272–299) has neurotoxicity by affecting mitochondrial respiratory function. However, the molecular mechanism(s) underlying the action of apoE4 (Δ272–299) in mitochondrial function remain poorly understood. Methods: The impact of neuronal apoE4 (Δ272–299) expression on ER stress, mitochondrial-associated membrane (MAM) formation, GRP75, calcium transport and mitochondrial impairment was determined in vivo and in vitro. Furthermore, the importance of ER stress or GRP75 activity in the apoE4 (Δ272–299)-promoted mitochondrial dysfunction in neuron was investigated. Results: Neuronal apoE4 (Δ272–299) expression induced mitochondrial impairment by inducing ER stress and mitochondrial-associated membrane (MAM) formation in vivo and in vitro. Furthermore, apoE4 (Δ272–299) expression promoted GRP75 expression, mitochondrial dysfunction and calcium transport into the mitochondria in neuron, which were significantly mitigated by treatment with PBA (an inhibitor of ER stress), MKT077 (a specific GRP75 inhibitor) or GRP75 silencing. Conclusions: ApoE4 (Δ272–299) significantly impaired neuron mitochondrial function by triggering ER stress, up-regulating GRP75 expression to increase MAM formation, and mitochondrial calcium overload. Our findings may provide new insights into the neurotoxicity of apoE4 (Δ272–299) against mitochondrial function and uncover new therapeutic targets for the intervention of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Pure organic room‐temperature phosphorescence (RTP) materials are useful for photoelectric, biochemical devices, and bioimaging sensors. In the last few years, dynamic covalent chemistry has aroused substantial attention as it offers a way to create intelligent materials with feedback and response functions. Through a Diels–Alder reaction, a [4+2] cycloaddition reaction between dienes and dienophiles, three polymers were synthesized that can be reversibly transformed by thermally reversible dynamic covalent bonds. All polymers show decent RTP emission with different colors. For the poly‐Br‐An solid, the absolute phosphorescence quantum yield reaches up to 12 %. This study provides a new method for the rational design and synthesis of tunable‐emission organic RTP materials via dynamic covalent bonds. [ABSTRACT FROM AUTHOR]

Pure organic room‐temperature phosphorescence (RTP) materials are useful for photoelectric, biochemical devices, and bioimaging sensors. In the last few years, dynamic covalent chemistry has aroused substantial attention as it offers a way to create intelligent materials with feedback and response functions. Through a Diels–Alder reaction, a [4+2] cycloaddition reaction between dienes and dienophiles, three polymers were synthesized that can be reversibly transformed by thermally reversible dynamic covalent bonds. All polymers show decent RTP emission with different colors. For the poly‐Br‐An solid, the absolute phosphorescence quantum yield reaches up to 12 %. This study provides a new method for the rational design and synthesis of tunable‐emission organic RTP materials via dynamic covalent bonds. [ABSTRACT FROM AUTHOR]

For the three-dimensional (3D) quasilinear wave equation Σi,j3=0 gi,j (∂u)∂i,j2u = 0 with coefficients independent of the solution u, a blowup result or global existence result has been completely established provided that the null condition does not hold or holds, respectively. In this paper and a subsequent paper (see [D. Bingbing, W. Ingo, and Y. Huicheng, The Small Data Solutions of General 3-D Quasilinear Wave Equations. II, preprint, 2014]), we will systematically study the more general 3D quasilinear wave equation Σi,j3=0 gij(u, ∂u)∂ij2u = 0 with coefficients depending simultaneously on u and ∂u. When the weak null condition holds, we show that the smooth small data solution exists globally in the paper. [ABSTRACT FROM AUTHOR]

Total syntheses of the erythrina alkaloids (±)-8-oxo-erythrinine and (±)-8-oxo-erythraline have been developed, based on a substrate-controlled intramolecular 6- exo- trig selective radical spirocyclization that establishes the quaternary center of the B-rings. An improved total synthesis of (±)-clivonine has also been reported, based on an intramolecular 6- endo-trig free-radical cyclization of a highly functionalized enamide, and a biomimetic ring-switch of a lycorine-type intermediate. These endo/ exo-selective sequences enabled us to rapidly assemble two different complex alkaloids from a common building block in an economical fashion. [ABSTRACT FROM AUTHOR]

Traditional luminescent materials including fluorescent probes suffer from notorious aggregation‐caused quenching in aqueous solutions. Although several approaches such as the aggregation‐induced emission effect have been developed, it remains a significant challenge to identify an effective and efficient strategy to resolve this issue. Herein, quaternary ammonium salts Q8PBn and Q8PNap as a novel class of bright near infrared window II (NIR‐II, 1000–1700 nm) probes are designed and synthesized, and the twisted intramolecular charge transfer formation at the excited state can be effectively suppressed for the newly designed probes. Furthermore, Q8PNap complexation with fetal bovine serum (Q8PNap/FBS) significantly increases the quantum yield by ≈32‐fold compared with PEGylated tertiary amine Q8P, and Q8PNap/FBS is successfully used to achieve high spatial and temporal resolution imaging of hind limb vasculature, lymphatic system, and small tumor metastasis, as well as precise NIR‐II imaging‐guided tumor and lymph node surgery in small animal models for the first time. [ABSTRACT FROM AUTHOR]