Instead of using organic solvents, a deep eutectic solvent (DES) composed of tetrabutylammonium bromide and imidazole (Bu4NBr/Im) was employed as a solvent for the first time to synthesize covalent ...organic frameworks (COFs). Due to the low vapor pressure of the Bu4NBr/Im‐based DES, a new carboxyl‐functionalized COF (TpPa‐COOH) was synthesized under environmental pressure. The as‐synthesized TpPa‐COOH has open channels, and the DES can be removed completely from the pores. The dye adsorption performance of TpPa‐COOH was examined for three organic dyes with similar molecular sizes: one anionic dye (eosin B, EB) and two cationic dyes (methylene blue, MB and safranine T, ST). TpPa‐COOH showed an excellent selective adsorption effect on MB and ST. The electronegative keto form in TpPa‐COOH might help to form electrostatic and π–π interactions between the π‐stacking frameworks of TpPa‐COOH and the positive plane MB and ST molecules. The adsorption isotherms of MB and ST on TpPa‐COOH were further investigated in detail, and the equilibrium adsorption was well modeled by using a Langmuir isotherm model. Together with hydrogen bonding, TpPa‐COOH showed higher adsorption capacity for ST than for MB (1135 vs. 410 mg g−1). These results could provide a guidance for the green synthesis of adsorbents in removing organic dyes from wastewater.
Waste not: A deep eutectic solvent has been used as a green solvent for the first time to synthesize a new carboxyl‐functionalized covalent organic framework, TpPa‐COOH, under environmental pressure. The as‐synthesized TpPa‐COOH exhibited good crystallinity, with ordered, open channels. Significantly, its high adsorption capacity could be used to remove cationic organic dyes from wastewater.
•GC-O revealed fifteen important odorants (IOs) in hepatopancreas of E. sinensis.•Optimized oxidation treatment conditions of PE extract was 175 °C for 60 min.•Hexanal, heptanal, nonanal, 2-nonanone ...and 2-pentylfuran identified from PE extract.•Nine PE species were important precursors of IOs in hepatopancreas of E. sinensis.
Flavor is critical to the commercial acceptance of the highly valued Chinese mitten crab (Eriocheir sinensis). This study investigated the important odorants (IOs) in male E. sinensis hepatopancreas formed from phosphatidylethanolamine (PE) in model systems. A total of fifteen IOs were detected by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). Among the IOs that were also detected as oxidation products of PE extract were hexanal, heptanal, nonanal, 2-pentylfuran and 2-octanone, and the optimized oxidation conditions of PE extract were 175 °C for 60 min. For further analysis, nine PE species were considered important precursors of IOs in E. sinensis. Odorants derived from PE (16:0/18:2), PE (18:0/18:2), PE (18:0/20:4), PE (16:0/22:6), and PE (18:0p/22:6) specie standards were detected, and their oxidative stabilities are discussed. These findings are important for understanding the comprehensive formation mechanism of IOs in E. sinensis, which may provide theoretical guidance for improving the overall flavor of aquatic products.
Space antenna reflectors are used by space vehicles to communicate with ground stations. These reflectors are generally subject to broadband random vibration and shock conditions during shipment and ...vehicle launch. While active vibration control methods can reduce any unexpected responses, sensors, controllers, power amplifiers, and actuators are all required to implement the control system. These additional external devices increase both the weight and the cost of the reflector, and reduce the reliability and safety of the space product. This study proposes a novel self-sensing vibration control method and applies a self-sensing electromagnetic transducer to suppress the vibration of a space antenna reflector. This transducer is used bifunctionally, acting as both an isolator and a velocity sensor. The vibration control principle of the proposed method is analyzed. A governing equation is established using the finite element method. A type of degree of freedom reduction method is used to obtain the response of the space antenna reflector. A ground experiment is then set up. The results demonstrate that the proposed self-sensing vibration control method can reduce the second-order and third-order vibrations of the space antenna reflector by 4 and 9 dB, respectively.
The objective of this study was to explore frozen storage stability of muscle protein of the obscure pufferfish using a semi-model system based on light exposure (LE), oxygen concentration (OC), and ...multiple freeze-thaw cycles (FTCs). The dorsal muscle of fifteen frozen fish was cut into small pieces (2 cm × 1.5 cm × 1 cm) and divided into 4 groups stored in differing conditions: one was stored in light with 0% oxygen (L-0), one in light with 20% oxygen (L-20), one in dark with 0% oxygen (D-0), and one in dark with 20% oxygen (D-20). All were subsequently subjected to five FTCs. Protein oxidation (PO) levels, protein structure, and water states were all assessed. The results showed that both LE and OC could significantly accelerate sulfhydryl and tryptophan loss, in the order of L-20 > L-0 and D-20 > D-0 during FTCs. Changes of protein structure were in line with the extent of PO indicated by surface hydrophobicity and UV absorbance. An increased PO also affected the water states, with higher PO resulting in immobilized water being more tightly trapped within the protein. However, thawing loss was shown to be independent of PO and the structural changes of myofibrillar protein.
•Light and oxygen could both accelerate PO during FTCs but through different pathways.•The conformational changes of MFP consistent with the extent of PO.•Immobilized water was more tightly trapped with the increased extent of PO.•The extent of PO has limited effect on thawing loss compared with mechanical damage.
Background and Purpose
New remedies are required for the treatment of diabetic neuropathic pain (DNP) due to insufficient efficacy of available therapies. Here, we used chemogenetic approaches ...combined with in vivo pharmacology to elucidate the role of basolateral amygdala (BLA) astrocytes in DNP pathogenesis and provide new insights into therapeutic strategies for DNP.
Experimental Approach
A streptozotocin‐induced DNP model was established. Designer receptors exclusively activated by designer drugs (DREADDs) were used to regulate astrocyte activity. Mechanical hyperalgesia was assessed using the electronic von Frey test. Anxiety‐like behaviours were detected using open field and elevated plus maze tests. Astrocytic activity was detected by immunofluorescence, and cytokine content was determined by ELISA.
Key Results
BLA astrocytes were regulated by DREADDs, and inhibition of BLA astrocytes attenuated mechanical allodynia and pain‐related negative emotions in DNP rats. In contrast, temporary activation of BLA astrocytes induced allodynia without anxious behaviours in naive rats. In addition, koumine (KM) alleviated mechanical allodynia and anxiety‐like behaviours in DNP rats, inhibited the activation of BLA astrocytes and suppressed the inflammatory response. Furthermore, persistent activation of BLA astrocytes through chemogenetics mimicked chronic pain, and KM alleviated the pain hypersensitivity and anxiety‐like behaviours.
Conclusion and Implications
DREADDs bidirectionally regulate the activity of BLA astrocytes, which proves for the first time the role of BLA astrocyte activation in the pathogenesis of DNP and represents a novel therapeutic strategy for DNP. KM ameliorates DNP, perhaps by inhibiting the activation of BLA astrocytes and reveal KM as a potential candidate for treating DNP.
Although the development of Gobi Desert in central and eastern Asia has greatly affected the regional and even the global climate, its precise origin and evolution have yet to be determined. The ...three preconditions for the formation of Gobi Desert are: i) a dry climate, ii) basin landforms and iii) abundant sediment production. In this study, we present a synthesis of both new and published data on the formation and evolution of Gobi Desert in central and eastern Asia. We conclude that the combined effects of mountain building, the mid-latitude westerly circulation and changes in the Asian monsoon, accompanied by global cooling, were principally responsible for the formation of modern Gobi Desert landscapes in central and eastern Asia during the late Pliocene. The arid climate in central and parts of eastern Asia probably developed in the early Cenozoic, from ~50 Ma. Related events included the collision of the Indian and Asian plates, the closure and complete retreat of the Paratethys Ocean from central Asia, and the growth of the Himalayas and the Tibetan Plateau in the Eocene through late Miocene, which blocked the water vapor supply and intensified the aridification of the Asian interior. Superimposed on the topographic changes was the process of stepwise global cooling since the early Oligocene, and in particular since the late Miocene, which controlled the formation and evolution of the Gobi Desert landscape. Global cooling weakened the Asian monsoon circulation, strengthened the westerly circulation and enhanced physical weathering processes in mountain areas, which together promoted both the aridification of the Asian interior and sediment production. These processes finally resulted in the establishment of the modern Gobi Desert landscape in the late Pliocene. We estimate that the modern Gobi Desert landscape was formed at ~2.6 Ma and was the result of the stepwise evolution of Asian topography and climate during the Cenozoic, dominated by Asian tectonic deformation and uplift, and the evolution of Asian monsoon climate and the westerly circulation, forced by global temperature change.
Since December 2019, COVID-19 has occurred unexpectedly and emerged as a health problem worldwide. Despite the rapidly increasing number of cases in subsequent weeks, the clinical characteristics of ...pediatric cases are rarely described. A cross-sectional multicenter study was carried out in 10 hospitals across Hubei province. A total of 25 confirmed pediatric cases of COVID-19 were collected. The demographic data, epidemiological history, underlying diseases, clinical manifestations, laboratory and radiological data, treatments, and outcomes were analyzed. Of 25 hospitalized patients with COVID-19, the boy to girl ratio was 1.27:1. The median age was 3 years. COVID-19 cases in children aged <3 years, 3.6 years, and ≥6-years patients were 10 (40%), 6 (24%), and 9 (36%), respectively. The most common symptoms at onset of illness were fever (13 52%), and dry cough (11 44%). Chest CT images showed essential normal in 8 cases (33.3%), unilateral involvement of lungs in 5 cases (20.8%), and bilateral involvement in 11 cases (45.8%). Clinical diagnoses included upper respiratory tract infection (n=8), mild pneumonia (n=15), and critical cases (n=2). Two critical cases (8%) were given invasive mechanical ventilation, corticosteroids, and immunoglobulin. The symptoms in 24 (96%) of 25 patients were alleviated and one patient had been discharged. It was concluded that children were susceptible to COVID-19 like adults, while the clinical presentations and outcomes were more favorable in children. However, children less than 3 years old accounted for majority cases and critical cases lied in this age group, which demanded extra attentions during home caring and hospitalization treatment.
In order to investigate and predict the quality of hepatopancreas of Eriocheir sinensis during frozen storage, fatty acid content, peroxide value (POV), acid value (AV) and anisidine value (AnV) were ...determined at −20, −40 and −80 °C, respectively. According to the investigative results, lipid oxidation indexes at −20 °C was higher than at −40 and −80 °C, and the degree of lipid oxidation was the least at −80 °C. In the meantime, the back propagation neural network with 10 neurons was developed to predict lipid stability of the samples during frozen storage with low MSE (0.00023) and high R2 (0.999). Besides, the changes to nutritional quality were evaluated using the index of atherogenesis (AI) and the index of thrombosis (TI). Furthermore, tri-step spectroscopy was applied to analyze and characterize the degree of lipid oxidation. The profile of characteristic peak was spatially revealed by the stereomicroscopy with group-peak at 2924 cm−1, 2854 cm−1, 1745 cm−1, 1641 cm−1, 1461 cm−1 and 1158 cm−1 and were unveiled by the second derivative infrared spectroscopy (SD-IR) for higher resolution, the samples stored at different temperatures were further identified through two-dimensional correlation infrared spectroscopy (2DCOS-IR).
•Lipid stability of hepatopancreas of Eriocheir sinensis was evaluated systematically.•BPNN were utilized first in frozen hepatopancreas of Eriocheir sinensis.•BPNN could accurately predict lipid oxidation indexs throughout the whole period.•Fatty acid profile changed progressively during frozen storage.•Tri-step IR spectroscopy was an effective method to characterize the lipid oxidation.
Designing efficient multifunctional electrocatalysts for water and urea splitting to produce green hydrogen presents a significant yet worthwhile challenge. Herein, the morphology and electronic ...structure of cobalt metaphosphate (Co2P4O12) by vanadium (V) doping, resulting in improved electrocatalytic activity and stability for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) are simultaneously regulated. Theory calculations show that V‐doped Co2P4O12 (V‐Co2P4O12) can boost the kinetics of catalytic reactions by optimizing the d‐band center of Co atoms and the binding strength of intermediates, as well as enhancing the density of states. Moreover, the doping of V into Co2P4O12 crystalline structure benefits the formation of a thicker amorphous layer during the catalytic process, which could enhance its alkaline corrosion resistance and stability. Additionally, the multilevel nanostructures of V‐Co2P4O12 provide rich active sites for catalytic reactions. As a result, a two‐electrode electrolyzer assembled by V‐doped Co2P4O12 delivers low voltages for overall water and urea splitting. The superior performance suggests that the proposed V‐doping strategy is a promising way to regulate electrocatalytic activity for catering to green electrocatalytic applications.
The morphology and electronic structure of the Co2P4O12 catalyst are simultaneously regulated by V doping, which endows the catalyst with enhanced hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) performance. Thanks to the excellent trifunctional catalytic performance, the assembled two‐electrode electrolyzers enable efficient overall water and urea splitting at low overpotentials.
Aims
Various mycophenolate mofetil (MMF) population pharmacokinetic (popPK) models have been developed to describe its PK characteristics and facilitate its optimal dosing in adult kidney transplant ...recipients co‐administered with tacrolimus. However, the external predictive performance has been unclear. Thus, this study aimed to comprehensively evaluate the external predictability of published MMF popPK models in such populations and investigate the potential influencing factors.
Methods
The external predictability of qualified popPK models was evaluated using an independent dataset. The evaluation included prediction‐ and simulation‐based diagnostics, and Bayesian forecasting. In addition, factors influencing model predictability, especially the impact of structural models, were investigated.
Results
Fifty full PK profiles from 45 patients were included in the evaluation dataset and 11 published popPK models were identified and evaluated. In prediction‐based diagnostics, the prediction error within ±30% was less than 50% in most published models. The prediction‐ and variability‐corrected visual predictive check and posterior predictive check showed large discrepancies between the observations and simulations in most models. Moreover, the normalized prediction distribution errors of all models did not follow a normal distribution. Bayesian forecasting demonstrated an improvement in the model predictability. Furthermore, the predictive performance of two‐compartment (2CMT) models incorporating the enterohepatic circulation (EHC) process was not superior to that of conventional 2CMT models.
Conclusions
The published models showed large variability and unsatisfactory predictive performance, which indicated that therapeutic drug monitoring was necessary for MMF clinical application. Further studies incorporating potential covariates need to be conducted to investigate the key factors influencing model predictability of MMF.
PDF
