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SrIrO3 (SIO) thin films were epitaxially grown on (001)-oriented 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) single-crystal substrates. Upon applying electric fields to the piezoelectric PMN-PT along the thickness direction, the electronic transport properties of SIO films can be in situ tuned and modulated by non-180° ferroelectric domain rotation-induced strain, piezoelectric strain, and rhombohedral-to-tetragonal structural phase transition-induced strain in the PMN-PT layer, respectively. Moreover, the weak negative magnetoresistance (MR) of the 60-nm SIO films could be modified by applying an electric field to the PMN-PT layer. At T = 2 K, upon the application of E = 4 kV/cm to the PMN-PT, MR at H = 9 T is reduced by 14.2% as compared to that under zero electric field, indicating in-plane compressive strain-induced suppression of the influence of quantum corrections to the conductivity in the SIO film. These results demonstrate that the electric-field controllable lattice strain is a simple approach to get insight into the strain-property relationships of 5d iridate thin films. [ABSTRACT FROM AUTHOR]

Transparent conductive oxides have attracted extensive attentions as a promising candidate for next-generation display materials. As a substitute for indium tin oxide, BaSnO3-based materials have been widely investigated with the improvement of electrical resistivity and optical transparency. Here, the effects of diverse rare-earth ions (R = La, Nd, Sm, Er) doping on the structural, electrical, and optical properties of RxBa1−xSnO3 films are systematically studied. The rare-earth ion doping improves the crystallinity of epitaxial RxBa1−xSnO3 films. And a rule for electrical performance optimization is revealed that the resistivity and metal-semiconductor transition temperature increase with increased atomic number of rare-earth ions. Further optimized composition for LaxBa1−xSnO3 is realized at x = 5% with the minimum resistivity of 0.31 mΩ cm. Moreover, all RxBa1−xSnO3 films exhibit a high transparency of greater than 90% in the visible region. This work demonstrates that among these four rare-earth ion doping, La-doping is the most effective approach to optimize the comprehensive properties of BaSnO3-based transparent conductive films. [ABSTRACT FROM AUTHOR]

Information processing with optoelectronic devices provides an alternative way to efficiently process hybrid optical and electronic signals. Ferroelectric field‐effect transistors (FeFETs) can effectively respond to external optical and electrical stimuli by modulating their polarization states. Here, a 2D FeFET is demonstrated by the epitaxial growth of high‐quality 2D bismuth layered oxyselenide (Bi2O2Se) films on PMN‐PT(001) ferroelectric single‐crystal substrates. Upon switching the polarization direction of PMN‐PT, the authors realize in situ, reversible, and nonvolatile manipulation of the resistance of Bi2O2Se thin film (≈877%). The device simultaneously exhibits a polarization‐dependent photoresponse through visible light (λ = 405 nm) and infrared light (IR, λ = 980 nm) illumination. Combining optical stimuli with ferroelectric gating, it is demonstrated that the devices not only show nonvolatile memory and optoelectronic responses, but also show coincidence detection of visible and IR light. This work holds great potential in constructing new multiresponse and multifunction 2D‐FeFETs. [ABSTRACT FROM AUTHOR]

Ferroelectrics are appealing candidates for photovoltaic applications. In this study, Bi5FeTi3O15 (BFTO) single layer and ZnO/BFTO bilayer films were deposited onto 0.7 wt% Nb-doped SrTiO3 (NSTO) electrically conducting single-crystal substrates to form Ag/BFTO/NSTO and Ag/ZnO/BFTO/NSTO photovoltaic devices. It was found that the insertion of an n-type semiconducting ZnO layer eliminates the built-in electric field between the Ag electrode and the BFTO film and results in the formation of a BFTO/ZnO p–n junction with a built-in electric field whose direction points to the BFTO film. These effects, together with the depolarization field within the BFTO film, provide a favorable energy level alignment for efficient electron extraction. As a result, the short circuit photocurrent density (Jsc) was improved by nearly 50 fold to 2.2 mA cm−2 and the output power density was increased by 15 fold to 0.09 mW cm−2 under ultraviolet light (λ = 405 nm) illumination. Upon the reversal of the ferroelectric polarization direction from downward to upward, the Jsc and the open circuit voltage (Voc) were increased by 2.5 and 4 fold for the Ag/BFTO/NSTO device and by 2.83 and 8.5 fold for the Ag/ZnO/BFTO/NSTO device, respectively. This work provides an effective way for developing efficient ferroelectric and semiconductor based photovoltaic devices. [ABSTRACT FROM AUTHOR]

NiO–Ni composite films were heteroepitaxially grown on (111)-oriented ferroelectric 0.31Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb2/3)O3-0.34PbTiO3 (PIN-PMN-PT) single-crystal substrates by pulsed laser deposition. The NiO films prepared in high vacuum are n-type conducting and possess room-temperature ferromagnetism, which originates from oxygen vacancies and the presence of the second Ni phase, respectively. Taking advantage of the electric-field-induced ferroelectric polarization charges, we realized in situ reversible and nonvolatile modulation of both the electrical resistance and magnetism of the film. A relative resistance change of ∼470% is obtained at room temperature, while an appreciable magnetization change of ∼15% was achieved at 50 K by switching the polarization states of PIN-PMN-PT. The coexistence of charge-density-tunable electronic and magnetic properties of NiO–Ni/PIN-PMN-PT heterostructures may provide a strategy to design charge-mediated multiferroic devices for nonvolatile memory and spintronic applications. [ABSTRACT FROM AUTHOR]

Enhanced green and red upconversion emissions under 980 nm excitation are observed in Ba0.85−xCa0.15TiO3:0.75%Er3+/xIn3+ lead-free ferroelectric ceramics which were synthesized by solid state reaction method. With increasing In3+ ions doping level from x = 0% mol the green and red emission intensities increase and reach the maximum at x = 1.75% mol. The maximum intensity of green emission at 550 nm is 20 times larger than In3+ ions undoped samples, which is unprecedented for Er3+-doped perovskite ferroelectric materials. Based on the ultraviolet-visible-near infrared absorption spectra, the enhancement of the luminescence intensity of the A-site In3+ doped Ba0.85−xCa0.15TiO3:0.75%Er/xIn ceramics is attributed to In3+-doping-induced relative increase in isolate Er3+ and decrease in the clustered-Er3+. The effects of In3+ doping on the crystal structure, dielectric, ferroelectric, piezoelectric properties of the ceramics were also studied and discussed. [ABSTRACT FROM AUTHOR]

Electric-field switchable multilevel nonvolatile resistance states are achieved at room temperature in Bi0.93Sb0.07/0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3(111) (PMN-0.29PT) heterostructures. During the initial poling of the PMN-0.29PT, the variation of the resistance of the Bi0.93Sb0.07 film with the electric field tracks the variation of the electric-field-induced in-plane strain of the PMN-0.29PT effectively, revealing that the resistance switching is dominated by the ferroelectric-domain-switching-induced lattice strain but not the domain-switching-induced polarization charges. A relative resistance change ΔR/R ∼ 7% at 300 K and up to ∼10% at 180 K were achieved near the coercive field EC of the PMN-0.29PT(111) substrate. At least five stable resistance states with good endurance properties could be obtained at room temperature by precisely controlling the electric-field pulse sequence as a result of the nonvolatile remnant strain transferring from the PMN-0.29PT to the film, providing a simple and energy efficient way to construct multistate resistive memory. [ABSTRACT FROM AUTHOR]

We epitaxially grew 7 mol. % Nd-doped BaSnO3 (NBSO) thin films on double-side polished SrTiO3 (001) single-crystal substrates and optimized the oxygen pressure (PO2), substrate temperature (TS), and film thickness (t) to achieve excellent structural, optical, and electrical performance. By keeping TS (=800 °C) constant, NBSO films prepared at PO2 = 10 Pa show the best crystallization, yielding a full-width at half-maximum (FWHM) of the x-ray diffraction rocking curve of 0.079° and exhibiting a room-temperature resistivity (ρ) of ∼1.85 mΩ cm and a volume carrier density (n) of ∼8.5 × 1020/cm3. By keeping PO2 (=10 Pa) constant, the room-temperature ρ of NBSO films could be reduced to as low as 0.5 mΩ cm by increasing TS from 700 to 825°; meanwhile, the volume carrier density and mobility show the maximum of 5.04 × 1020/cm3 and 24.9 cm2/Vs, respectively, for TS = 825 °C. For all as-grown NBSO thin films, the optical transmittance in the visible wavelength region is larger than 80%. The optimized comprehensive properties of the NBSO films with FWHM = 0.11°, ρ = 0.5 mΩ cm, μ = 24.9 cm2/Vs, and T > 80% are superior to those of other rare-earth and 4d- and 5d-transition metal-doped BaSnO3 thin films. [ABSTRACT FROM AUTHOR]

Superconducting thin films of FeSe 0.5 Te 0.5 are epitaxially grown on piezoelectric 0.71Pb(Mg 1/3 Nb 1/2 )O 3 -0.29PbTiO 3 (PMN-PT) single-crystal substrates. Upon the application of an electric field to the PMN-PT along the thickness direction the superconducting properties of the FeSe 0.5 Te 0.5 films, such as the normal-state resistance, superconducting phase transition temperature, upper critical field, critical current, and coherence length are in situ modified via the ferroelectric polarization rotation, converse piezoelectric effect, and structural phase transition of the PMN-PT. Our findings demonstrate that the combination of superconducting thin films with piezoelectrically active PMN-PT offers a promising approach for exploring the intrinsic lattice strain effects of iron-based superconducting systems. [ABSTRACT FROM AUTHOR]

A series of In3+-doped Ba0.85Ca0.15TiO3:0.75%Er3+/xIn3+ (BCT:Er/xIn) lead-free piezoelectric ceramics with excellent upconversion luminescence were synthesized by the solid state reaction method. The effects of In3+ content on the crystal structure, ferroelectric, dielectric, piezoelectric, and upconversion luminescence properties were systematically studied. Under 980 nm excitation, a giant enhancement of the green emission (550 nm) by 10 times is achieved upon 2.5% mol In3+ doping, which is rarely observed in rare-earth ions-doped perovskite ferroelectric materials. The ultraviolet-visible-near infrared absorption measurements show that the In3+ doping may improve the dissolution of Er3+ ions and modify the isolate-/clustered-Er3+ ratio for x ≤ 2.5%, resulting in the enhancement of the absorption cross-section, thereby contributing to the enhancement of green luminescence. Unfortunately, the In3+ doping suppresses the ferroelectric and piezoelectric properties of the BCT:Er/xIn ceramics. This problem can be resolved by adding a small amount (1 mol%) of Yb3+ to the BCT:Er/xIn ceramics to restore their good ferroelectric and piezoelectric properties. Such In3+ and rare-earth ions co-doped ceramics with greatly enhanced upconversion luminescence and good ferroelectricity and piezoelectricity may have potential applications in electro-optical devices. [ABSTRACT FROM AUTHOR]

(1 − x)KNaLiNbSbO- xBiNaBaZrO [(1 − x)KNLNS- xBNBZ] (0 ≤ x ≤ 0.05) lead-free piezoelectric ceramics were prepared by using the conventional solid-state reaction method. The relationships among the composition, phase structure, phase volume fraction, microstructure, dielectric, ferroelectric, and piezoelectric properties as well as the phase diagram are established. Rietveld refinements of X-ray diffraction patterns show that with increasing doping level the volume fractions of the orthorhombic and tetragonal phases evolve from 58.7 and 41.3% for x = 0 to 1.7 and 98.3% for x = 0.05, which has strong impacts on the piezoelectric coefficient d and Curie temperature T . Upon the doping of BNBZ an orthorhombic-tetragonal ( O- T) phase boundary forms near room temperature, resulting in an optimum d ~ 288 pC/N, T ~ 305 °C, a converse piezoelectric coefficient d ~ 391 pm/V, and a field-induced strain S ~ 0.156% for the x = 0.035 ceramics. These results demonstrate that a balanced development of d and T can be realized by choosing suitable doping materials and content. [ABSTRACT FROM AUTHOR]

Here we report the structural, dielectric, ferroelectric, piezoelectric, and magnetic properties of zirconium-doped 0.67BiFeGaO-0.33BaZrTiO (BFG-BZT) lead-free ceramics. Structural investigations reveal that the doped Zr ions (up to x = 0.15) can be fully incorporated into the host lattice. Dielectric measurements demonstrate that with increasing Zr content, both the ferroelectric Curie temperature T and the dielectric constant decrease monotonously, and that the dielectric constant exhibits relaxor behaviors upon Zr doping. At the same time, the remnant polarization P increases and then decreases, with the maximum P ∼ 26 µC/cm for x = 0.025. One of the noteworthy results is that the remanent magnetic moment at room temperature increases up to 0.17 emu/g with increasing x from 0 to 0.15, which is attributed to enhanced lattice distortions due to Zr doping. The coexistence of strong ferroelectricity and ferromagnetism at room temperature implies that the BFG-BZT could be potential candidate materials for multiferroic device applications. [ABSTRACT FROM AUTHOR]

Hydrogenation of silicon tetrachloride(STC) in the presence ofsilicon was investigated both thermodynamically and experimentally.The thermodynamic results revealed that the reaction is thermodynamicallyconstrained and the STC equilibrium conversion is nearly temperature-independentbut increases with increasing pressure and H2/STC feedratio. Trichlorosilane (TCS) was calculated to be the dominant product,with trace amounts of dichlorosilane (DCS) and HCl as feasible byproducts.Experimental tests were conducted in a fixed-bed reactor loaded withsilicon. The results indicated that the reaction is kinetically restrictedin the absence of a catalyst. Adding CuCl to the silicon mass bedwas found to result in a dramatic increase in the STC conversion,and Cu3Si was determined to be the active species. In allof the tests runs, TCS was determined to be the dominant product,and the STC reaction rate was found to increase markedly as the temperatureand STC partial pressure increased but not to depend on the siliconparticle size. [ABSTRACT FROM AUTHOR]

The authors inadvertently used the unit "Oersted (Oe)" of the magnetic field instead of the correct unit "Tesla (T)." The sentence "On one hand, the greater difference of I M i SB S sb can be ascribed to the larger absolute difference in carrier density (7.6 × 10 SP 18 sp cm SP -3 sp ) between the two polarization states (Fig. S3, supplementary material), as compared with the corresponding value at 300 K (1.19 × 10 SP 18 sp cm SP -3 sp )." should be corrected as "On one hand, the greater difference of I M i SB S sb can be ascribed to the larger absolute difference in carrier density (7.6 × 10 SP 22 sp cm SP -3 sp ) between the two polarization states (Fig. [Extracted from the article]

SrIrO3 (SIO) thin films were epitaxially grown on (001)-oriented 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) single-crystal substrates. Upon applying electric fields to the piezoelectric PMN-PT along the thickness direction, the electronic transport properties of SIO films can be in situ tuned and modulated by non-180° ferroelectric domain rotation-induced strain, piezoelectric strain, and rhombohedral-to-tetragonal structural phase transition-induced strain in the PMN-PT layer, respectively. Moreover, the weak negative magnetoresistance (MR) of the 60-nm SIO films could be modified by applying an electric field to the PMN-PT layer. At T = 2 K, upon the application of E = 4 kV/cm to the PMN-PT, MR at H = 9 T is reduced by 14.2% as compared to that under zero electric field, indicating in-plane compressive strain-induced suppression of the influence of quantum corrections to the conductivity in the SIO film. These results demonstrate that the electric-field controllable lattice strain is a simple approach to get insight into the strain-property relationships of 5d iridate thin films. [ABSTRACT FROM AUTHOR]

Integration of different functional materials into a device in which the physical properties can be tuned using an electric field in a reversible and nonvolatile manner is highly desired for the fabrication of compact and energy‐efficient multifunctional electronic devices. The integration of In2O3‐based semiconductor thin films with ferroelectric 0.71PbMg1/3Nb2/3O3‐0.29PbTiO3 (PMN‐0.29PT) single crystals in ferroelectric‐field‐effect‐transistor devices that allow for the tuning of carrier density, carrier type, Fermi level, and their related properties in a reversible and nonvolatile manner, is reported. Specifically, gating of In2–xCrxO3 (x = 0, 0.02, 0.05, 0.08, 0.11) films with a PMN‐0.29PT layer provides a means to reversibly tune and modulate the resistivity of the films up to an on‐and‐off ratio of 5.2 × 104% in a nonvolatile manner at room temperature. Such resistivity modulation is associated with reversible and nonvolatile transformation of the carrier type between n‐type and p‐type due to polarization switching. Additionally, reversible switching of resistivity is realized utilizing DEME‐TFSI ionic liquid as a top‐gate material. These results demonstrate that electrical‐voltage control of physical properties using PMN‐xPT as both substrate and gating material provides a highly effective approach to study the carrier‐density/type‐related physical properties of semiconductor films. [ABSTRACT FROM AUTHOR]

Currently, the mechanical vapor recompression (MVR) system is extensively used for single salt separation, but the relevant research on mixed salt system treatment is still in initial stage. As a very common salt solution system, sodium chloride–potassium chloride–water system can be readily found in many processes. It is no doubt of great significance to separate their crystals from the mixed solution in an efficient and environmentally friendly way. Therefore, with the aid of Aspen Plus software, this study aims to design an MVR evaporation system capable of treating sodium chloride–potassium chloride–water system. Subsequently, the analysis about the start‐up schemes and some influencing factors in the steady‐state operation are carried out, so as to provide some guidance and reference for the future technical route to separate mixed salt system with low energy consumption. [ABSTRACT FROM AUTHOR]

Stoichiometric Cr 2 Se 3 single crystals are particular layer-structured antiferromagnets, which possess a noncollinear spin configuration, weak ferromagnetic moments, moderate magnetoresistance (MR ∼14.3%), and poor metallic conductivity below the antiferromagnetic phase transition. Here, we report an interesting >16 000% colossal magnetoresistance (CMR) effect in Ti (1.5 atomic percent) lightly doped Cr 2 Se 3 single crystals. Such a CMR is approximately 1143 times larger than that of the stoichiometric Cr 2 Se 3 crystals and is rarely observed in layered antiferromagnets and is attributed to the frustrated spin configuration. Moreover, the Ti doping not only dramatically changes the electronic conductivity of the Cr 2 Se 3 crystal from a bad metal to a semiconductor with a gap of ∼15 meV but also induces a change in the magnetic anisotropy of the Cr 2 Se 3 crystal from strong out-of-plane to weak in-plane. Further, magnetotransport measurements reveal that the low-field MR scales with the square of the reduced magnetization, which is a signature of CMR materials. The layered Ti:Cr 2 Se 3 with the CMR effect could be used as two-dimensional (2D) heterostructure building blocks to provide colossal negative MR in spintronic devices.

We report on the growth of high-quality stoichiometric layered Cr 2 Se 3 single crystals with metallic and noncollinear antiferromagnetic ground state using the chemical vapor transport (CVT) method. The crystals show weak ferromagnetism in the in-plane and out-of-plane directions below the Neél temperature ( T N ), however, the field-cooled out-of-plane magnetization at 500 Oe and 10 K (∼0.24 μ B /f.u.) is approximately 15 times larger than that of the in-plane one, indicating strong c -axis easy uniaxial magnetic anisotropy, which is further supported by the in-plane and out-of-plane isothermal anisotropic magnetic hysteresis loops and the angular dependent magnetoresistance (MR). The latter also reveals a decrease of the coercive field of the crystal upon the tilting of the weak ferromagnetic easy axis away from the direction of the magnetic field. Further, the out-of-plane isothermal MR are negative below T N and show butterfly shapes for T < 10 K and couple with the magnetic hysteresis M ( H ) loop. These results may help researchers better understand the interplay between the weak ferromagnetism and the magnetotransport properties of 2D itinerant noncollinear antiferromagnetic systems., (© 2020 IOP Publishing Ltd.)

A series of Cr-doped In 2- x Cr x O 3 (ICO) semiconductor thin films were epitaxially grown on (111)-oriented 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.29PbTiO 3 (PMN-0.29PT) single-crystal substrates by the pulsed laser deposition. Upon the application of an electric field to the PMN-0.29PT substrate along the thickness direction, we realized in situ, reversible, and nonvolatile control of the electronic properties and Fermi level of the films, which are manifested by abundant physical phenomena such as the n-type to p-type transformation, metal-semiconductor transition, metal-insulator transition, crossover of the magnetoresistance (MR) from negative to positive, and a large nonvolatile on-and-off ratio of 5.5 × 10 4 % at room temperature. We also strictly disclose that both the sign and the magnitude of MR are determined by the electron carrier density of ICO films, which could modify the s - d exchange interaction and weak localization effect. Our results demonstrate that the ferroelectric gating approach using PMN-PT can be utilized to gain deeper insight into the carrier-density-related electronic properties of In 2 O 3 -based semiconductors and provide a simple and energy efficient way to construct multifunctional devices which can utilize the unique properties of composite materials.

Single-phase (00 l)-oriented Bi 2 Te 3 topological insulator thin films have been deposited on (111)-oriented ferroelectric 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.29PbTiO 3 (PMN-PT) single-crystal substrates. Taking advantage of the nonvolatile polarization charges induced by the polarization direction switching of PMN-PT substrates at room temperature, the carrier density, Fermi level, magnetoconductance, conductance channel, phase coherence length, and quantum corrections to the conductance can be in situ modulated in a reversible and nonvolatile manner. Specifically, upon the polarization switching from the positively poled P r + state (i.e., polarization direction points to the film) to the negatively poled P r - (i.e., polarization direction points to the bottom electrode) state, both the electron carrier density and the Fermi wave vector decrease significantly, reflecting a shift of the Fermi level toward the Dirac point. The polarization switching from P r + to P r - also results in significant increase of the conductance channel α from -0.15 to -0.3 and a decrease of the phase coherence length from 200 to 80 nm at T = 2 K as well as a reduction of the electron-electron interaction. All these results demonstrate that electric-voltage control of physical properties using PMN-PT as both substrates and gating materials provides a simple and a straightforward approach to realize reversible and nonvolatile tuning of electronic properties of topological thin films and may be further extended to study carrier density-related quantum transport properties of other quantum matter.

We report the fabrication of 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.29PbTiO 3 (PMN-0.29PT)-based ferroelectric field effect transistors (FeFETs) by the epitaxial growth of cobalt-doped tin dioxide (SnO 2 ) semiconductor thin films on PMN-0.29PT single crystals. Using such FeFETs we realized in situ, reversible, and nonvolatile manipulation of the electron carrier density and achieved a large nonvolatile modulation of the resistance (∼330%) of the SnO 2 :Co films through the polarization switching of PMN-0.29PT at 300 K. Particularly, combining the ferroelectric gating with piezoresponse force microscopy, X-ray diffraction, Hall effect, and magnetoresistance (MR), we rigorously disclose that both sign and magnitude of the MR are intrinsically determined by the electron carrier density, which could modify the s-d exchange interaction of the SnO 2 :Co films. Furthermore, we realized multilevel resistance states of the SnO 2 :Co films by combining the ferroelectric gating with ultraviolet light illumination, demonstrating that the FeFETs have potential applications in multistate resistive memories and electro-optical devices.

Drought is a major threat to agriculture production worldwide. Mitogen-activated protein kinases (MAPKs) play a pivotal role in sensing and converting stress signals into appropriate responses so that plants can adapt and survive. To examine the function of MAPKs in the drought tolerance of tomato plants, we silenced the SpMPK1, SpMPK2, and SpMPK3 genes in wild-type plants using the virus-induced gene silencing (VIGS) method. The results indicate that silencing the individual genes or co-silencing SpMPK1, SpMPK2, and SpMPK3 reduced the drought tolerance of tomato plants by varying degrees. Co-silencing SpMPK1 and SpMPK2 impaired abscisic acid (ABA)-induced and hydrogen peroxide (H2O2)-induced stomatal closure and enhanced ABA-induced H2O2 production. Similar results were observed when silencing SpMPK3 alone, but not when SpMPK1 and SpMPK2 were individually silenced. These data suggest that the functions of SpMPK1 and SpMPK2 are redundant, and they overlap with that of SpMPK3 in drought stress signaling pathways. In addition, we found that SpMPK3 may regulate H2O2 levels by mediating the expression of CAT1. Hence, SpMPK1, SpMPK2, and SpMPK3 may play crucial roles in enhancing tomato plants' drought tolerance by influencing stomatal activity and H2O2 production via the ABA-H2O2 pathway.