Multidrug resistance (MDR) occurs frequently after long-term chemotherapy, resulting in refractory cancer and tumor recurrence. Therefore, combatting MDR is an important issue. Autophagy, a ...self-degradative system, universally arises during the treatment of sensitive and MDR cancer. Autophagy can be a double-edged sword for MDR tumors: it participates in the development of MDR and protects cancer cells from chemotherapeutics but can also kill MDR cancer cells in which apoptosis pathways are inactive. Autophagy induced by anticancer drugs could also activate apoptosis signaling pathways in MDR cells, facilitating MDR reversal. Therefore, research on the regulation of autophagy to combat MDR is expanding and is becoming increasingly important. We summarize advanced studies of autophagy in MDR tumors, including the variable role of autophagy in MDR cancer cells.
Natural medicines were the only option for the prevention and treatment of human diseases for thousands of years. Natural products are important sources for drug development. The amounts of bioactive ...natural products in natural medicines are always fairly low. Today, it is very crucial to develop effective and selective methods for the extraction and isolation of those bioactive natural products. This paper intends to provide a comprehensive view of a variety of methods used in the extraction and isolation of natural products. This paper also presents the advantage, disadvantage and practical examples of conventional and modern techniques involved in natural products research.
Bioinspired artificial haptic neuron system has received much attention in the booming artificial intelligence industry for its broad range of high‐impact applications such as personal healthcare ...monitoring, electronic skins, and human–machine interfaces. An artificial haptic neuron system is designed by integrating a piezoresistive sensor and a Nafion‐based memristor for the first time in this paper. The piezoresistive sensor serves as a sensory receptor to transform mechanical stimuli into electric signals, and the Nafion‐based memristor serves as the synapse to further process the information. The pyramid‐structured sensor exhibits excellent sensitivity (6.7 × 107 kPa−1 in 1–5 kPa and 3.8 × 105 kPa−1 in 5–50 kPa) and durability (>7000 cycles), while the memristor realizes fundamental synaptic functions under low power consumption (10–200 pJ) and remains stable for over 104 consecutive tests. The integrated system can detect tactile stimuli encoded with temporal information, such as the count, frequency, duration and speed of the external force. As a proof‐of‐concept, English characters recognition with high accuracy can be achieved on the system under a supervised learning method. This work shows promising potential in bioinspired sensing systems owing to the high performance, excellent durability, and simple fabrication procedure.
An artificial haptic neuron system is designed by integrating a piezoresistive sensor and a Nafion‐based memristor for the first time. The pyramid‐structured sensor exhibits excellent sensitivity and durability, while the memristor realizes fundamental synaptic functions under low power consumption and remains stable for over 104 consecutive tests. The integrated system can detect tactile stimuli encoded with temporal information.
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The development of bifunctional and stable non-noble metal electrocatalysts for the high-performance hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is very important and ...challenging for renewable energy. Herein, for the first time, a nickel-chromium layered double hydroxide (NiCr-LDH) nanosheet array was developed as a bifunctional electrocatalyst towards overall water splitting. By tuning different Ni/Cr ratios of LDHs, the optimized Ni
Cr
-LDH shows extraordinary HER activity with an ultralow overpotential of 138 mV at 100 mA cm
, compared with all of the reported Ni-based LDHs (NiFe-LDH, NiCo-LDH, NiMn-LDH, NiTi-LDH, NiV-LDH etc.) and even outperforming Pt/C catalysts. The small overpotential of 319 mV at 100 mA cm
for the OER and outstanding durability at 1.55 V (vs. RHE) for 30 hours can also be achieved for Ni
Cr
-LDH. Notably, a two-electrode electrolyzer with a Ni
Cr
-LDH bifunctional electrocatalyst as both the anode and the cathode can work for at least 30 hours with a cell voltage of merely 1.55 V at 10 mA cm
. Both experimental and density functional theoretical calculations show that the Cr
ions within the LDH layer serve as charge transfer sites and thus effectively boost the intrinsic electrochemical activity. Therefore, this work provides a new NiCr-LDH system as a more efficient metal hydroxide for bifunctional water splitting electrocatalyst.
Indoor detection of volatile organic compounds (VOCs) concentration is necessary due to the serious toxicity hazards even at trace level. However, physisorbents usually exhibit weak interactions ...especially in the presence of trace concentrations of VOCs, thus exhibiting poor responsive signal. Herein, we report a new flexible metal–organic framework (MOF) that exhibits interesting pore‐opening behavior after immersing in H2O. The pore‐opening phase shows significant (≈116 folds) and extremely fast (<1 minute) fluorescence enhancement after being exposed to saturated benzene vapor. The limit of detection concentration for benzene vapor can be calculated as 0.133 mg L−1. Thus this material represents the first MOF to achieve visual detection of trace benzene vapor by the naked eyes. Theoretical calculations and single‐crystal structure reveal that the special “bilateral π–π stacking” interactions between the host and guest, which facilitate electron transfer and greatly enhance the intensity of fluorescence.
A new flexible metal–organic framework (MOF) exhibits significant and sensitive fluorescence “turn‐on” behavior for benzene vapor by virtue of unique “bilateral π–π stacking” interactions, enabling visual detection of a trace level of benzene for the first time.
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A spiro‐axis skeleton not only introduces circularly polarized luminescence (CPL) into thermally activated delayed fluorescence (TADF) molecules but also enhances the intramolecular through space ...charge transfer (TSCT) process. Spiral distributed phenoxazine and 2‐(trifluoromethyl)‐9H‐thioxanthen‐9‐one‐10,10‐dioxide act as donor and acceptor units, respectively. The resulting TADF enantiomers, (rac)‐OSFSO, display emission maxima at 470 nm, small singlet‐triplet energy gap (ΔEST) of 0.022 eV and high photoluminescence quantum yield (PLQY) of 81.2 % in co‐doped film. The circularly polarized OLEDs (CP‐OLEDs) based on (R)‐OSFSO and (S)‐OSFSO display obvious circularly polarized electroluminescence (CPEL) signals with dissymmetry factor up to 3.0×10−3 and maximum external quantum efficiency (EQEmax) of 20.0 %. Moreover, the devices show remarkably low efficiency roll‐off with an EQE of 19.3 % at 1000 cd m−2 (roll‐off ca. 3.5 %), which are among the top results of CP‐OLEDs.
A chiral spiro‐axis skeleton introduced the circularly polarized luminescence property into TADF molecules and enhanced the intramolecular through space charge transfer process. The resulting TADF enantiomers display obvious CPEL signals with |gEL| factor up to 3.0×10−3 and EQE of 20.0 % with remarkably low efficiency roll‐off, which are among the top results of CP‐OLEDs.
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This study focused on the newest evidence of the relationship between forest environmental exposure and human health and assessed the health efficacy of forest bathing on the human body as well as ...the methodological quality of a single study, aiming to provide scientific guidance for interdisciplinary integration of forestry and medicine.
Through PubMed, Embase, and Cochrane Library, 210 papers from January 1, 2015, to April 1, 2019, were retrieved, and the final 28 papers meeting the inclusion criteria were included in the study.
The methodological quality of papers included in the study was assessed quantitatively with the Downs and Black checklist. The methodological quality of papers using randomized controlled trials is significantly higher than that of papers using non-randomized controlled trials (p < 0.05). Papers included in the study were analyzed qualitatively. The results demonstrated that forest bathing activities might have the following merits: remarkably improving cardiovascular function, hemodynamic indexes, neuroendocrine indexes, metabolic indexes, immunity and inflammatory indexes, antioxidant indexes, and electrophysiological indexes; significantly enhancing people's emotional state, attitude, and feelings towards things, physical and psychological recovery, and adaptive behaviors; and obvious alleviation of anxiety and depression.
Forest bathing activities may significantly improve people's physical and psychological health. In the future, medical empirical studies of forest bathing should reinforce basic studies and interdisciplinary exchange to enhance the methodological quality of papers while decreasing the risk of bias, thereby raising the grade of paper evidence.
Increasing CO2 concentration in the atmosphere is believed to have a profound impact on the global climate. To reverse the impact would necessitate not only curbing the reliance on fossil fuels but ...also developing effective strategies capture and utilize CO2 from the atmosphere. Among several available strategies, CO2 reduction via the electrochemical or photochemical approach is particularly attractive since the required energy input can be potentially supplied from renewable sources such as solar energy. In this Review, an overview on these two different but inherently connected approaches is provided and recent progress on the development, engineering, and understanding of CO2 reduction electrocatalysts and photocatalysts is summarized. First, the basic principles that govern electrocatalytic or photocatalytic CO2 reduction and their important performance metrics are discussed. Then, a detailed discussion on different CO2 reduction electrocatalysts and photocatalysts as well as their generally designing strategies is provided. At the end of this Review, perspectives on the opportunities and possible directions for future development of this field are presented.
CO2 reduction to useful chemical fuels via the electrochemical or photochemical approach represents promising directions to convert and utilize this greenhouse gas molecule. The Review summarizes recent progress on the development, engineering, and understanding of CO2 reduction electrocatalysts and photocatalysts.
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A convenient, fast and selective water analysis method is highly desirable in industrial and detection processes. Here a robust microporous Zn-MOF (metal-organic framework, Zn(hpi2cf)(DMF)(H
O)) is ...assembled from a dual-emissive H
hpi2cf (5-(2-(5-fluoro-2-hydroxyphenyl)-4,5-bis(4-fluorophenyl)-1H-imidazol-1-yl)isophthalic acid) ligand that exhibits characteristic excited state intramolecular proton transfer (ESIPT). This Zn-MOF contains amphipathic micropores (<3 Å) and undergoes extremely facile single-crystal-to-single-crystal transformation driven by reversible removal/uptake of coordinating water molecules simply stimulated by dry gas blowing or gentle heating at 70 °C, manifesting an excellent example of dynamic reversible coordination behaviour. The interconversion between the hydrated and dehydrated phases can turn the ligand ESIPT process on or off, resulting in sensitive two-colour photoluminescence switching over cycles. Therefore, this Zn-MOF represents an excellent PL water-sensing material, showing a fast (on the order of seconds) and highly selective response to water on a molecular level. Furthermore, paper or in situ grown ZnO-based sensing films have been fabricated and applied in humidity sensing (RH<1%), detection of traces of water (<0.05% v/v) in various organic solvents, thermal imaging and as a thermometer.
Cobalt imidazolate frameworks are classical electrocatalysts for the oxygen evolution reaction (OER) but suffer from the relatively low activity. Here, a non‐3d metal modulation strategy is presented ...for enhancing the OER activity of cobalt imidazolate frameworks. Two isomorphous frameworks Co4(MO4)(eim)6 (M=Mo or W, Heim=2‐ethylimidazole) having Co(eim)3(MO4) units and high water stabilities were designed and synthesized. In different neutral media, the Mo‐modulated framework coated on a glassy carbon electrode shows the best OER performances (1 mA cm−2 at an overpotential of 210 mV in CO2‐saturated 0.5 m KHCO3 electrolyte and 2/10/22 mA cm−2 at overpotential of 388/490/570 mV in phosphate buffer solution) among non‐precious metal catalysts and even outperforms RuO2. Spectroscopic measurements and computational simulations revealed that the non‐3d metals modulate the electronic structure of Co for optimum reactant/product adsorption and tailor the energy of rate‐determining step to a more moderate value.
Non‐3D for 3D: Introducing non‐3d metal oxide units into a cobalt imidazolate framework results in the drastic enhancement of electrocatalytic performance of the oxygen evolution reaction in neutral media.
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