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As a major nominally anhydrous mineral (NAM) in the Earth’s upper mantle, orthopyroxene could host up to several hundred parts per million H2O in its crystal structure and transport the H2O to the deep Earth. To study the effect of structural H2O on the elasticity of orthopyroxene, we have measured the single-crystal elasticity of Mg1.991Al0.065Si1.951O6 with 842–900 ppm H2O and 1.64 ± 0.20 wt% Al2O3 at ambient conditions using Brillouin spectroscopy. The best-fit single-crystal elastic moduli (Cijs), bulk (KS0), and shear (G0) modulus of the hydrous Al-bearing orthopyroxene were determined as: C11 = 235(2) GPa, C22 = 173(2) GPa, C33 = 222(2) GPa, C44 = 86(1) GPa, C55 = 82(1) GPa, C66 = 82(1) GPa, C12 = 75(3) GPa, C13 = 67(2) GPa, and C23 = 49(2) GPa, KS0 = 111(2) GPa, and G0 = 78(1) GPa. Systematic analysis based on the results presented in this and previous studies suggests that the incorporation of 842–900 ppm H2O would increase C13 by 12.0(7)% and decrease C23 by 8.6(8)%. The effects on C11, C22, C33, C44, C66, KS0, and VP are subtle if not negligible when considering the uncertainties. The C55, C12, G0, and VS are not affected by the presence of structural H2O. Although laboratory experiments show that Fe,Al-bearing orthopyroxenes can host up to 0.8 wt% H2O in its structure, future high-pressure-temperature elasticity measurements on orthopyroxene with higher H2O content are needed to help better quantify this effect.

Cratonic lithosphere is a vast host for deep recycled carbon, trapping up to several weight percent CO2 among its compositions1,2 at depths overlapping the seismic mid-lithospheric discontinuities (MLDs)3-5. However, the role of carbonates, especially for the latest discovered amorphous calcium carbonate (CaCO3)6, is underestimated in forming MLDs. Using the pulse-echo-overlap method in a Paris-Edinburgh press coupled with X-ray diffraction, we explored the acoustic velocities of CaCO3 under high pressure-temperature (P-T) conditions relevant to the cratonic lithosphere. Two anomalous velocity drops were observed associated with the phase transition from aragonite to amorphous phase as well as with pressure-induced velocity drop in amorphous phase around 3 GPa, respectively. Both drops are comparable with approximately 35% and 52% reductions for compressional (VP) and shear (VS) wave velocities, respectively. The VP and VS values of the amorphous CaCO3 above 3 GPa are about 1/2 and 1/3 of those of the major upper-mantle minerals, respectively, and they are the same with aragonite below 3 GPa. These velocity reduction by the presence of CaCO3 would readily cause MLDs at depths of 70–120 km dependent on the geotherm even if only 1-2 vol.% CaCO3 presents in the cratonic lithosphere. The CaCO3-originated MLDs is weak so as to be expected to influence the stability, rifting, and delamination of the craton7.

Layered nickel-rich cathodes generally suffer from their unstable surface because of lithium impurities. Thus, building an interface with both high electrochemical stability and electroactivity is ...

Intrahepatic cholangiocarcinoma is a malignant tumor originating from intrahepatic bile ducts. Surgical therapy, radiotherapy, and chemotherapy are taken to treat this disease, but it is prone to recurrence and metastasis, with poor prognosis. Therefore, it is of great significance to explore new targets and molecular mechanisms for the development of cholangiocarcinoma cells. Clinical cholangiocarcinoma tissues from patients and four human cholangiocarcinoma cell lines were analyzed for microRNA‐373 (miR‐373) expression. For investigating whether miR‐373 directly modulated unc‐51 like autophagy activating kinase 1 (ULK1), dual‐luciferase reporter assay was performed. In addition, CCK‐8 assay, flow cytometry, western blot, and immunofluorescence were applied to evaluate the proliferation, apoptosis, and autophagy of cholangiocytic hepatocellular carcinoma cells. miR‐373 downregulation was observed in clinical tissues and cell lines of cholangiocarcinoma. Overexpression of miR‐373 reduced proliferation, enhanced apoptosis, and raised expression levels of pro‐apoptosis proteins including BCL2 associated X (Bax), Caspase‐3, and Caspase‐9. Moreover, overexpression of miR‐373 downregulated expression levels of microtubule‐associated protein 1A/1B‐light chain 3 (LC3)‐II, Beclin‐1, and promoted P62 expression on mRNA and protein levels. After miR‐373 knockdown, all indexes of apoptosis and autophagy mentioned above were reversed. Luciferase activity was decreased after cotransfection of miR‐373 mimic and wild‐type ULK1 vector. Also, miR‐373 overexpression inhibited ULK1 expression. Importantly, overexpression of miR‐373 weakened expressions of ULK1, LC3, Beclin‐1, and Bcl‐2, and enhanced expressions of P62, Bax, Caspase‐3, and Caspase‐9. miR‐373 mimic treatment and subsequent ULK1 overexpression, induced reverse regulation in expressions of these proteins, compared with overexpression of miR‐373 only. miR‐373 targeted ULK1 to initiate inhibition of autophagy and subsequent promotion of apoptosis in cholangiocarcinoma cells.

Bufalin has been reported to kill various types of cancer including human colorectal cancer. Our previous study demonstrated that bufalin induced cell death via autophagy in HT-29 and Caco-2 colon cancer cells, but the action of bufalin remains unclear. This study was conducted to investigate the role of bufalin in other colon cancer HCT-116 and SW620 cells as well as its potential mechanism.The effect of bufalin in HCT-116 and SW620 colon cancer cells was detected by assessing cell viability and cell death. Apoptotic cells were analyzed by Western blot and trypan blue dye exclusion assay. Mitochondrial ROS production was analyzed by flow cytometry after DCFDA and DHR-123 staining. The potential mechanism was investigated via pharmacological inhibitors.Bufalin had high potency against HCT-116 and SW620 cells with IC50 values of 12.823 ± 1.792 nM and 26.303 ± 2.498 nM in HCT-116 and SW620 cells, respectively. Bufalin decreased cell viability, increased cell death as well as caspase-3 downstream target (cleaved PARP) accumulation, and these actions were significantly blocked by pan-caspase inhibitor zVAD-FMK. Mechanistically, ROS production, but neither the NAD(P)H oxidase, AMPK, ERK nor p38, is responsible for bufalin-induced apoptotic cell death. Moreover, bufalin-induced ROS generation is derived from mitochondria.Bufalin significantly induces apoptosis in HCT-116 and SW620 colon cancer cells via mitochondrial ROS-mediated caspase-3 activation. We believe that our novel findings will greatly alter our current understanding on the anti-cancer mechanism of bufalin in colon cancer cells and will pave the way for further exploiting the clinical application.

Most nanomaterials with good adsorption properties are restricted from being applied in electrochemical detection due to the lack of active sites and poor electrocatalytic reactivity. Here, we found a synergistic catalysis effect of N vacancies and ∼5 nm Au nanoparticles in Au/N-deficient-C3N4 for highly sensitive electrochemical detection of Pb(II) with anti-interference via a defect-engineering strategy. N vacancy defects were introduced into g-C3N4 to prepare N-deficient-C3N4, which showed a significantly enhanced electrochemical sensitivity toward Pb(II) (689.0 μA μM−1 cm−2). The sensitivity of Au/N-deficient-C3N4 dramatically rose to 1223.0 μA μM−1 cm−2 because of the synergistic catalysis effect, which was approximately 4 times as large as that of pure g-C3N4. The N vacancies in g-C3N4 could greatly improve the selective adsorption of Pb(II), and ∼5 nm Au nanoparticles enhanced the catalysis of materials. High concentration of other common ions (Hg(II), Cu(II), or Cd(II)) did not interfere in the electrochemical detection of Pb(II). A strong chemical interaction between Pb(II) and Au/N-deficient-C3N4 was confirmed by X-ray photoelectron spectroscopy results, which was possibly responsible for the anti-inference properties. This work provides a new method to make semiconductors with intrinsically poor electrochemical activity potential materials in the electrochemical analysis field by defect-engineering and synergistic catalysis.

AFL is a liver disease caused by long-term excessive drinking, it is characterized by steatosis. Understanding the regulatory mechanism of steatosis is crucial for the treatment of AFL. Rev-erbα has been implicated in regulation of lipid metabolism. However, the role and the underlying mechanisms of Rev-erbα in AFL remains unknown. In this study, the antagonists or agonists of Rev-erbα as well as Rev-erbα shRNA were applied in vitro and vivo. Triglyceride and lipid droplets accumulation were measured by using TG kit and ORO staining. Lipid synthesis related factor Srebp1c and lipid β-oxidation regulatory factor Pparα were measured by using Western blot, qRT-PCR and immunohistochemistry analysis. Autophagy activity was measured by western blot and electron microscope, and lysosomal probe was used to labeled lysosomal acidity. We observed that the expression of Rev-erbα was significantly increased in vivo and vitro, and Rev-erbα activation mediated steatosis in L-02 cells. then, inhibition/down-expression of Rev-erbα improved the triglyceride and lipid droplets accumulation and the abnormal expression of Pparα and Srebp1c through enhancing the autophagy activity. Furthermore, down-expression of Rev-erbα up-regulated the nuclear expression of Bmal1, which regulated the autophagy activity in vitro. Collectively, these findings indicate that Rev-erbα induces liver steatosis and leads to the progression of AFL. Our study reveals a novel steatosis regulatorymechanism in AFL and suggest that Rev-erbα might be a potential therapeutic target for AFL.

The concept of creating crystal defect sites at interface of sensing materials is of ultimate importance for electrochemical sensing performance, yet the status of surface electron transfer and specific location of active sites for analyte remain unclear at the atomic level. Here, we construct a highly sensitive electrochemical sensing interface via engineering surface electron and active site on the unconventional CN vacancy (VCN)-mediated Mn-Fe Prussian blue analogue (PBA) hollow structure. We modulate the surface electron transfer dynamic and identify specific reaction location of VCN-mediated Mn-Fe PBA to obtain a limit of detection of 0.013 μM (3σ method) with a high sensitivity of 7193.64 μA cm−2 μM−1 toward Pb(II), which is fifteen that of pristine Mn-Fe PBA (without VCN). By combining experiments with theoretical calculations, we demonstrate that the VCN regulate the electron transfer from metal Fe to Mn atoms, rendering the Mn atoms as active sites for Pb(II) reaction. We also identify a relatively strong interaction between Mn atom and analyte Pb(II) by calculation result of great orbital overlapping of Mn–Pb bond. The adsorbed Pb(II) will undergo redox reaction in situ without considering adsorption-desorption rate on the surface of the sensing material.

The surface areas and the exposure of adsorption sites of nanomaterials can both affect the adsorption of heavy metal ions, and then lead to a diverse electrochemical detection response. However, it is an unsolved mystery that which one is the key factor for detection. Here, Fe2O3 hollow nanocubes with larger surface areas and Fe2O3 nanorods with more active adsorption sites are successfully synthesized derived from Prussian blue. The Fe2O3 with two different morphologies are applied to modified bare electrodes that can serve as sensing interface for the electrochemical analysis of Pb(II). Interestingly, the Fe2O3 nanorods with (010) plane, as an electrochemical sensor, are observed to be more advantageous than hollow nanocubes with (006) plane. The underlying mechanism about the diverse electrochemical performance between the two materials is sufficiently proved by Brunauer-Emmett-Teller and X-ray photoelectron spectroscopy. Remarkably, the evidences clearly suggest that a large surface area is not dominant to obtain a good analysis ability; while the exposed specific adsorption site on the surface of nanomaterials shows more determinant.

The contamination containing trace heavy metal ions (HMIs) has received great attentions, as it poses serious threats to ecological system and human health. Hence, the developments of a rapid technology for the real-time and on-line detection of HMIs are of significance. Considering the drawbacks of singular spectral method and electrochemical method, electrochemical spectral method has been proposed as a powerful analytical technology for the detection of trace HMIs because of its great sensitivity, anti-interference ability and super low limit of detection (LOD). As such, in this review, we primarily described the recent advances of representative electrochemical spectral methods and their applications, including electrochemical atomic absorption spectrometry (EC-AAS), electrochemical total reflection X-ray fluorescence and X-ray fluorescence (EC-TXRF/XRF), and electrochemical laser-induced breakdown spectroscopy (EC-LIBS). Additionally, we basically introduced the electrochemical preconcentration methods generally used prior to spectral methods, including electrodeposition and electroadsorption. Based on the overview of these methods, we also addressed up-to-date challenges of in-situ electrochemical spectral methods, for which additional researches are needed to carry out.

Developing a new ultrasensitive interface to detect As(III) is highly desirable because of its seriously toxic and low concentration in drinking water. Recently, Fe3O4 nanoparticles of high adsorption toward As(III) become very promising to be such an interface, which is still limited by the poor understanding of their surface physicochemical properties. Herein, we report that dumbbell-like Au/Fe3O4 nanoparticles, when being modified the screen-printed carbon electrode, can serve as an efficient sensing interface for As(III) detection with an excellent sensitivity of 9.43 μA ppb–1 and a low detection limit of 0.0215 ppb. These outstanding records were attributed to the participation of Fe(II)/Fe(III) cycle on Fe3O4 surface in the electrochemical reaction of As(III) redox, as revealed by X-ray photoelectron spectroscopy, X-ray absorption near edge structure, and extended X-ray absorption fine structure. This work provides new insight into the mechanism of electroanalysis from the viewpoint of surface activ...

Mutual interference is a severe issue that occurs during the electrochemical detection of heavy metal ions. This limitation presents a notable drawback for its high sensitivity to specific targets. Here, we present a high electrochemical sensitivity of ∼237.1 μA cm–2 μM–1 toward copper(II) [Cu(II)] based on oxygen-deficient titanium dioxide (TiO2–x) nanosheets. We fully demonstrated an atomic-level relationship between electrochemical behaviors and the key factors, including the high-energy (001) facet percentage, oxygen vacancy concentration, surface −OH content, and charge carrier density, is fully demonstrated. These four factors were quantified using Raman, electron spin resonance, X-ray photoelectron spectroscopy spectra, and Mott–Schottky plots. In the mutual interference investigation, we selected cadmium(II) [Cd(II)] as the target ion because of the significant difference in its stripping potential (∼700 mV). The results show that the Cd(II) can enhance the sensitivity of TiO2–x nanosheets toward ...

An ultrasensitive electrochemical detection of heavy metal ions is achieved via defect- and phase-engineering of Mn-mediated MoS2 nanosheets. We find for the first time that chemical interactions between Pb(ii) and active S atoms in Mn-MoS2 facilitate the electron transfer and in situ catalytic redox reactions.

Nanocrystals generally suffer from agglomeration because of the spontaneous reduction of the system surface energy, resulting in blocking the active sites from reacting with target ions, and then severely reducing the electrochemical sensitivity. In this article, a highly ordered self-assembled monolayer array is successfully constructed using ∼14 nm Co0.6Fe2.4O4 nanocubes uniformly and controllably distributed on the surface of a working electrode (glass carbon plate). The large area and high exposure of the surface defects on Co0.6Fe2.4O4 nanocubes are clearly characterized by high-resolution transmission electron microscopy (HRTEM) and atomic-resolution high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). Expectedly, a considerable sensitivity of 2.12 μA ppb-1 and a low limit of detection of 0.093 ppb are achieved for As(III) detection on this highly homogeneous sensing interface; this excellent electroanalysis performance is even better than that of noble metals electrodes. Most importantly, this approach of uniformly distributing the small-sized defective nanoparticles on the electrode surface provides a new opportunity for modifying the electrodes, as well as the realization of their applications in the field of environmental electroanalysis for heavy metal ions.

Recent seismic studies suggested an anisotropic Mantle Transition Zone (MTZ) in areas adjacent to subducted slabs. Wadsleyite is the main anisotropy contributor in the upper MTZ, therefore the interpretation of these seismic observations requires the knowledge of single-crystal elastic moduli ( C i j s ) and the deformation-induced lattice preferred orientation (LPO) of wadsleyite. Wadsleyite can host up to 3 wt% water in its crystal structure as point defects in the form of hydroxyl groups, however, the combined effect of water content, Fe content, and pressure on the C i j s of wadsleyite remains unclear. In this study, we measured the high-pressure single-crystal elasticity of a synthetic hydrous Fe-bearing wadsleyite (0.14 (4) wt% water, Fe#=9.4, Fe3+/ΣFe=0.3) up to 18.2 (2) GPa. In combination with previous experimental data, we separated the effects of pressure, water, and Fe contents on the C i j s and intrinsic elastic anisotropy of wadsleyite. Our results suggest that the intrinsic elastic anisotropy of wadsleyite decreases with pressure, water, and Fe contents. At 15 GPa, increasing the water content by 0.1 wt% or Fe# by 1 decreases the V P and V S anisotropy of wadsleyite by ∼1.1-1.3%, and ∼0.8-1.3% in average, respectively. Combining the LPO determined in previous deformation experiments, we modeled the seismic anisotropy in the upper MTZ generated by a sub-vertical mantle flow near cold subducted slabs and a sub-horizontal mantle flow in the ambient mantle. In both scenarios, the LPO of wadsleyite leads to VSV (vertically polarized shear wave velocity) > VSH (horizontally polarized shear wave velocity). Our results suggest that wadsleyite may account for a weak anisotropic MTZ (

The intracontinental Ordos Basin hosts many large uranium deposits, and its evolution was controlled by the surrounding orogenic belts during the Paleozoic to Mesozoic. Paleocurrent data of the Jurassic Zhiluo Formation reveal that its sedimentary detritus were transported dominantly from southwest to northeast in the basin. However, the detrital zircon age pattern of the Zhiluo Formation is similar to those of the Inner Mongolia Paleo-uplift, the Central Asian Orogenic Belt (CAOB), the Yinshan Block, and the Khondalite Belt to the north but is remarkably different from those of the Qinling Orogenic Belt (QOB) and the North Qilian Belt to the south. Discriminant diagrams using immobile elements also reveal that the detritus of the Zhiluo Formation are dominated by felsic volcanic rocks and andesitic arc rocks, consistent with rock types in its northern orogenic units. The Zhiluo sandstones show high chemical index of weathering values (68–83), suggesting long-distance transportation and intensive ...

Intrinsically low conductivity and poor reactivity restrict many semiconductors from electrochemical detection. Usually, metal- and carbon-based modifications of semiconductors are necessary, making them complex, expensive, and unstable. Here, for the first time, we present a surface-electronic-state-modulation-based concept applied to semiconductors. This concept enables pure semiconductors to be directly available for ultrasensitive electrochemical detection of heavy-metal ions without any modifications. As an example, a defective single-crystalline (001) TiO2 nanosheet exhibits high electrochemical performance toward Hg(II), including a sensitivity of 270.83 μA μM–1 cm–2 and a detection limit of 0.017 μM, which is lower than the safety standard (0.03 μM) of drinking water established by the World Health Organization (WHO). It has been confirmed that the surface oxygen vacancy adsorbs an O2 molecule while the Ti3+ donates an electron, forming the O2•– species that facilitate adsorption of Hg(II) and ser...

It still remains unclear that the intrinsic structure-sensing property interplay of diverse transition metal oxides based sensing materials, although they have been applied in the field of environmental analysis and have achieved great progress. In this work, we performed X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and in situ electrochemical experiment to investigate the structure-sensing interplay of Mn-Co oxide (MnCo2O4) multi-shell hiberarchy microsphere. The comprehensive studies conclusively show that the active sites on MnCo2O4 surface work as key role in determining the electrochemical behavior through the aspect of adsorption and electrocatalytic activity. In detail, the exposed oxygen on the surface of MnCo2O4 forming amounts of –OH can act as grippers to adsorb the Pb(II) in water, and then the adsorbed Pb(II) can directly occur redox in situ by the mediation of Mn(II)/(III) and Co(II)/(III) cycle on the exposed Mn and Co active sites. As a result, an excellent electroanalytical behavior (sensitivity of 120.72 µA µM−1) toward Pb(II) could be effectively improved on MnCo2O4. The fabricated electrode also showed impressive electroanalytical performance for Pb(II) in mining subsidence area. Our findings will provide new insights and effective directions for designing ultr-sensitive nanomaterials based on variable valence mediation engineering in tuning the activity of transition metal oxides.

Jadeite is a major mineral phase (up to 50 vol%) in the subducted sediments/crust with continental origin, which are one of the major heterogeneities and important enriched geochemical reservoirs (such as EM-1 and EM-2) for incompatible elements in the Earth's interior. Identifying and locating the enriched geochemical heterogeneities requires knowledge of the elastic properties of relevant mineral phases at high pressure-temperature conditions. Unfortunately, the single-crystal elastic properties of jadeite have never been measured at high-pressure conditions, partially due to its low crystal symmetry. In this study, we have experimentally determined the single-crystal elastic moduli of jadeite at high pressures for the first time up to 18 GPa at the ambient temperature condition using Brillouin spectroscopy. Fitting the third-order finite strain equation of state to the velocity-pressure data yields K S 0 ′ =3.9(1), G 0 ′ =1.09(4) with ρ 0 =3.302(5) g/cm3, KS0=138(3) GPa, and G0=84(2) GPa. In addition, we have also conducted synchrotron single-crystal X-ray diffraction experiments up to 25 GPa and 700 K. The fitting of a Holland-Powell type thermal-pressure Birch-Murnaghan equation of state yields K T 0 ′ =3.8(2) and α 0 =3.4(5) ×10−5 K−1. Based on the obtained thermoelastic parameters of jadeite, the density and seismic velocities of continent-derived sediments/crust are modeled at the depth range from 200 to 500 km. The seismic velocities of the subducted continental sediments/crust become extremely fast at depths greater than ∼300 km, up to 11.8% and 14.7% faster than the Vp and Vs of the ambient mantle, and 5.6% and 7.3% faster than the Vp and Vs of the subducted oceanic crust. The existence of even a small amount of the subducted continental sediments/crust can result in strong seismic anomalies in the Earth's interior.

An ultrasensitive electrochemical detection of heavy metal ions is achieved via defect- and phase-engineering of Mn-mediated MoS2 nanosheets. We find for the first time that chemical interactions between Pb(ii) and active S atoms in Mn-MoS2 facilitate the electron transfer and in situ catalytic redox reactions.

Mutual interference is a severe issue that occurs during the electrochemical detection of heavy metal ions. This limitation presents a notable drawback for its high sensitivity to specific targets. Here, we present a high electrochemical sensitivity of ∼237.1 μA cm

Nanocrystals generally suffer from agglomeration because of the spontaneous reduction of the system surface energy, resulting in blocking the active sites from reacting with target ions, and then severely reducing the electrochemical sensitivity. In this article, a highly ordered self-assembled monolayer array is successfully constructed using ∼14 nm Co

Intrinsically low conductivity and poor reactivity restrict many semiconductors from electrochemical detection. Usually, metal- and carbon-based modifications of semiconductors are necessary, making them complex, expensive, and unstable. Here, for the first time, we present a surface-electronic-state-modulation-based concept applied to semiconductors. This concept enables pure semiconductors to be directly available for ultrasensitive electrochemical detection of heavy-metal ions without any modifications. As an example, a defective single-crystalline (001) TiO

An improved electron current model of graded heterojunction AlGaAs/GaAs HBTs is presented to account for the effect of varied electron quasi-Fermi level from the emitter region to the base region, the base push-out effect and the self-heating effect. For the self-heating effect, two kinds of thermal boundary conditions in one dimension are included, which are heat insulation at the emitter contact and fixed temperature at the collector contact and the reverse case. In each boundary condition, the more accurate b-e junction temperature model is established, and incorporated into the electron. current formula to form the combined model. A comparison of this model with the numerical simulated results from the basic thermoelectric coupled equations is made, and excellent agreements are obtained.

The class B large-signal power characteristics of AlGaAs/GaAs heterojunction bipolar transistors are simulated using a one-dimensional model. The effects of various kinds of structure with uniform base, bandgap graded base and doping graded base on power characteristics are studied. It is found that the power gain reaches a maximum value at a moderate level of Al mole fraction x = 0.1 at the base-emitter metallurgical boundary. To maintain the average base doping constant, the power gain is increased with the graded exponent due to the reduced input power and the slightly increased output power for a given input signal. Based on the assumption of uniform heat distribution over the device, the self-heating effects on power characteristics are also investigated. It is shown that if the mismatching problem between the device and its external circuits is not considered and the temperature dependence of the electron mobility is taken as unαT−0.2, a rise of temperature leads to an increase in the output power, which is opposite to the results of the current gain in dc steady-state.