Correlation between fat-to-muscle mass ratio and cognitive impairment in elderly patients with type 2 diabetes mellitus: a cross-sectional study.

BACKGROUND: Fat to muscle mass ratio (FMR), a novel index integrating fat and muscle composition, has garnered attention in age-related conditions such as type 2 diabetes mellitus (T2DM) and neurodegenerative diseases. Despite this research on the relationship between FMR and cognitive impairment (CI) in T2DM remains scarce. This study aimed to investigate the sex-specific association between FMR and CI in elderly T2DM patients. METHODS: A total of 768 elderly (> 60 years) T2DM in-patients (356 men and 412 women) were recruited from the Department of Endocrinology at Tianjin Nankai University affiliated hospital. Bioelectrical Impedance Analysis (BIA) was used to assess body composition, and Montreal Cognitive Assessment (MoCA) was used to evaluate cognitive performance. T2DM patients were categorized into normal cognitive function (NC) and cognitive impairment (CI) groups based on MoCA scores and stratified by sex. Binary logistic regression was employed to examine the association between FMR and CI. RESULTS: Among the participants, 42.7% of men and 56.3% of women experienced cognitive deterioration. Women with CI exhibited lower body mass index (BMI) and skeletal muscle mass index (SMI), while men with cognitive disorders showed lower SMI, FMR, and higher fat mass index (FMI). FMR was consistently unrelated to cognition in females, irrespective of adjustment made. However, in males, FMR was significantly associated with an increasing risk of cognitive dysfunction after adjusting for demographic and clinical variables (OR: 1.175, 95% CI: 1.045-1.320, p = 0.007). Furthermore, for each 0.1 increase in FMR, the incidence of CI rose by 31.1% after additional adjustment for BMI. In males, the prevalence of CI increased sequentially across FMR quartiles (p < 0.05). CONCLUSION: Elderly T2DM men with high FMR had unfavorable cognitive function. FMR is independently associated with an increased risk of CI in male T2DM patients regardless of BMI.

High-Performance and Polarization-Sensitive Imaging Photodetector Based on WS2 /Te Tunneling Heterostructure.

Next-generation imaging systems require photodetectors with high sensitivity, polarization sensitivity, miniaturization, and integration. By virtue of their intriguing attributes, emerging 2D materials offer innovative avenues to meet these requirements. However, the current performance of 2D photodetectors is still below the requirements for practical application owing to the severe interfacial recombination, the lack of photoconductive gain, and insufficient photocarrier collection. Here, a tunneling dominant imaging photodetector based on WS2 /Te heterostructure is reported. This device demonstrates competitive performance, including a remarkable responsivity of 402 A W-1 , an outstanding detectivity of 9.28 × 1013 Jones, a fast rise/decay time of 1.7/3.2 ms, and a high photocurrent anisotropic ratio of 2.5. These outstanding performances can be attributed to the type-I band alignment with carrier transmission barriers and photoinduced tunneling mechanism, allowing reduced interfacial trapping effect, effective photoconductive gains, and anisotropic collection of photocarriers. Significantly, the constructed photodetector is successfully integrated into a polarized light imaging system and an ultra-weak light imaging system to illustrate the imaging capability. These results suggest the promising application prospect of the device in future imaging systems.

Global rigorous coupled wave analysis for design of multilayer metasurface absorbers.

In this work, a novel Global NV-ETM RCWA method is proposed to accelerate the optimization of the periodic stepped radar absorbing structure. This method is based on the rigorous coupled-wave analysis (RCWA) utilizing the normal vector field (NV) and enhanced transmittance matrix (ETM) approach. The NV field dramatically improves the convergence rate for both dielectric and magnetic metasurfaces. The Global NV-ETM RCWA algorithm is developed to further accelerate the complete search calculations. Using the proposed method, the periodic stepped radar absorbing structures are efficiently optimized to realize the entire band absorption in 2-18 GHz. The optimization results demonstrate the Global NV-ETM RCWA method significantly increase the computational efficiency, with a 38-fold improvement over direct NV-ETM RCWA calculations when the truncation order N=3. This method provides a powerful tool for designing metasurface absorbers with various desired functionalities.

Light-triggered 2D electron gas in a GaN-based HEMT with sandwiched p-GaN layers.

In this work, a p-n junction-coupled metal-insulator-semiconductor (MIS) normally-off high-electron-mobility transistor (HEMT) UVPD is proposed. A two-dimensional electron gas (2DEG) at the AlN/U-GaN interface is entirely depleted with a dark current of 1.97 × 10-11 A because of the design of the sandwiched p-GaN layers. Under 365 nm illumination, the 2DEG is light triggered at Vds = 1 V with a high light on/off ratio of over 107 at a light power density of 286.39 mW·cm-2. Meanwhile, it exhibits fast rise and decay times of 248.39 and 584.79 µs, respectively. Moreover, a maximum responsivity (R) of 2.33 A/W, a maximum EQE of 793%, and a D* of 1.08 × 1013 Jones are obtained at Vds = 1 V. This can be attributed to the built-in electric fields in the configuration, which accelerate the flow of photogenerated carriers into the AlN/U-GaN channel. Additionally, the device showcases stable durability, repeatability, and a low driving voltage, making it highly suitable for applications in UV communication and space exploration.

Polarization-sensitive UV photodetector based on ReSe2/GaN mixed-dimensional heterojunction.

Polarization-sensitive photodetectors in the ultraviolet (UV) region have been favored for their great meaning in the field of military and civilian. UV photodetectors based on GaN have aroused much attention due to high photocurrent and high sensitivity. However, the dependence on external power sources and the limited sensitivity to polarized UV light significantly impede the practical application of these photodetectors in UV-polarized photodetection. Herein, a polarization-sensitive UV photodetector based on ReSe2/GaN mixed-dimensional van der Waals (vdWs) heterojunction is proposed. Owing to the high-quality junction and type-II band alignment, the responsivity and specific detectivity reach values of 870 mA/W and 6.8 × 1011 Jones, under 325 nm illumination, respectively. Furthermore, thanks to the strong in-plane anisotropy of ReSe2, the device is highly sensitive to polarized UV light with a photocurrent anisotropic ratio up to 6.67. The findings are expected to bring new opportunities for the development of highly sensitive, high-speed and energy-efficient polarization-sensitive photodetectors.

Role of Peripheral Blood T Helper 17 Cells in Non-Small Cell Lung Cancer of Different Clinical Stages, Pathological Types and Differentiation Degrees.

BACKGROUND: We aimed to explore the roles of T helper 17 (Th17) cells and cytokines interleukin 17 (IL-17), IL-6, IL-4, transforming growth factor ß (TGF-ß) and γ-interferon (IFN-γ) in the peripheral blood of patients with non-small cell lung cancer (NSCLC) of different clinical stages, pathological types, and differentiation degrees. METHODS: A total of 120 NSCLC patients admitted and 80 healthy people receiving physical examinations from June 2019 to October 2021 were enrolled as the case group (TNM stage: I, II, III and IV; pathological type: adenocarcinoma and squamous cell carcinoma; differentiation degree: low and moderate-high) and the control group, respectively. The serum levels of IL-17, IL-6, IL-4, TGF-ß and IFN-γ were measured using an enzyme-linked immunosorbent assay. Th17 cells were counted by flow cytometry. RESULTS: The case group had higher levels of Th17 cells, IL-17, IL-6, IL-4, and TGF-ß and lower IFN-γ level in the peripheral blood than those of the control group (p < 0.05). NSCLC patients with different TNM stages had significantly different levels of Th17 cell, IL-17, IL-6, TGF-ß, and IFN-γ (p < 0.05). The expression levels of Th17 and IL-6 in patients with lowly differentiated NSCLC were lower than those of patients with moderately and highly differentiated NSCLC, while the IFN-γ expression level followed an opposite trend (p < 0.05). The count of Th17 cells in the peripheral blood of NSCLC patients had significantly positive correlations with IL-17, IL-6, IL-4, and TGF-ß levels, but negative correlation with IFN-γ level (p < 0.05). CONCLUSIONS: The count of Th17 cells increases significantly in NSCLC patients and has correlations with TNM stage and differentiation degree.

Multiple herbicide resistance in a Cyperus difformis population in rice field from China.

Herbicide resistance is rapidly emerging in Cyperus difformis in rice fields across China. The response of a C. difformis population GX-35 was tested against five acetolactate synthase (ALS)-inhibiting herbicides, auxin herbicide MCPA and photosynthesis II (PSII)-inhibitor bentazone. Population GX-35 evolved multiple resistance to ALS-inhibiting herbicides (penoxsulam, bispyribac­sodium, pyrazosulfuron-ethyl, halosulfuron-methly and imazapic) and auxin herbicide MCPA, with resistance levels of 140-, 1253-, 578-, 18-, 13-, and 21-fold, respectively, compared to the susceptible population. In this population, ALS gene expression was similar to that of the susceptible population. However, an Asp376Glu mutation in ALS gene was observed, leading to reduced inhibition of in-vitro ALS activities by five ALS-inhibiting herbicides. Furthermore, CYP71D8, CYP77A3, CYP78A5 and three ABC transporter genes (cluster-14412.23067, cluster-14412.25321, and cluster-14412.24716) over-expressed in absence of penoxsulam. On the other hand, an UGT73C1 and an ABC transporter (cluster-14412.25038) were induced by penoxsulam. Additionally, both over-expression and induction were observed for CYP74, CYP71A1, UGT88A1 and an ABC transporter (cluster-14412.21723). The GX-35 population has indeed evolved multiple herbicide resistance in China. Therefore, a diverse range of weed control tactics should be implemented in rice field.

Dual-Function of Cation-Doping to Activate Cationic and Anionic Redox in a Mn-Based Sodium-Layered Oxide Cathode.

Recently, sodium-ion batteries have shown great potential for energy storage owing to their favorable electrochemical properties and intrinsic cost performance, which fuels the research and development of Mn-based layered oxides as promising sodium-ion cathodes. However, the undesirable structural evolution and oxygen redox impose great challenge on the cycling stability and rate capability of such cathodes. In this work, it is reported that Fe and Al can effectively tailor the Na2/3 Mn2/3 Fe1/6 Al1/6 O2 to trigger a stable cationic and anionic redox behavior. In situ X-ray diffraction analysis confirms the retention of a stable P2 phase upon cycling, and density functional theory results demonstrate that Al3+ doping can strengthen the covalency of MnO bond. The Na2/3 Mn2/3 Fe1/6 Al1/6 O2 cathode can retain 90% of its initial capacity within the voltage range of 2.0-4.2 V versus Na+ /Na at 200 mA g-1 after 100 cycles. Moreover, ex situ X-ray photoelectron spectroscopy reveals that the specific capacity can be replenished by the synergistic reactions between Fe3+ /Fe4+ /Fe3+ and O2- /(O2 )n - pairs within the voltage range of 4.0-4.4 V versus Na+ /Na, which is also elucidated by theoretical calculation.

Uniform Na Metal Plating/Stripping Design for Highly Reversible Solid-State Na Metal Batteries at Room Temperature.

Solid-state alkaline metal batteries are highly sought out for their improved energy density and security over the current lithium-ion batteries. However, their practical application is heavily hindered by the interfacial issues originating from the solid electrolyte/electrode mismatch. This work demonstrates that a CuO coating layer as an active interphase can thoroughly promote the intimate contact between a Na3 Zr2 Si2 PO12 solid electrolyte and a Na metal anode through an in situ conversion reaction. The resultant Cu/Na2 O matrix forms a mixed electron/ion conducting scaffold, which facilitates stable and homogeneous Na metal plating without dendrite formation. Moreover, the symmetric Na metal cell realizes impressively steady plating/stripping cycles for 5000 h even under a high current density of 0.3 mA cm-2 . The novelty is further manifested as a room-temperature solid-state Na metal full battery of Na3 V1.5 Al0.5 (PO4 )3 |CuO@NZSPO|Na is assembled and exhibits a highly reversible cyclability (99.85% coulombic efficiency and 99.0% capacity retention) under a charge/discharge rate of 5 C for 2250 cycles. This work effectively solves the interfacial issues at the Na metal/solid electrolyte interface and provides a convenient way toward high-performance solid-state Na metal batteries operated at room temperature.

Solid-State Na Metal Batteries with Superior Cycling Stability Enabled by Ferroelectric Enhanced Na/Na3 Zr2 Si2 PO12 Interface.

Solid-state metal batteries are attracting unprecedented concern because of their high energy density and safety. However, their service life, especially at high specific density, is hindered by the undesirable reversibility of metal anodes, owing to the inhomogeneous ion distribution and awkward charge transfer dynamics at the electrode/electrolyte interface. In this work, it is well demonstrated that ferroelectric phase BaTiO3 reinforced Na3 Zr2 Si2 PO12 ceramic electrolyte can deconcentrate the distribution of charge transfer and self-accelerate Na+ migration at the Na/Na3 Zr2 Si2 PO12 interface upon cycling, realizing a compact Na deposition morphology together with a high critical current density (1.05 mA cm-2 at ambient conditions). Assembled symmetric cells based on the proposed composite electrolyte render stable cycling up to 1000 h at 0.3 mA cm-2 . Specifically, the all solid-state sodium metal batteries paired with Na3 V1.5 Cr0.5 (PO4 )3 cathode material can deliver a capacity of 95 mAh g-1 at 100 mA g-1 and maintain 84.4% of the initial capacity after 400 cycles. This excellent electrochemical performance clearly confirm the feasibility of the introduction of ferroelectric BaTiO3 to suppress the dendrite nucleation and Na propagation within ceramic electrolyte. This research offers new insight into the rational design of inorganic electrolyte, revealing dendrite-free and long-term all-solid-state sodium batteries.

Non-Layered Te/In2 S3 Tunneling Heterojunctions with Ultrahigh Photoresponsivity and Fast Photoresponse.

A photodetector based on 2D non-layered materials can easily utilize the photogating effect to achieve considerable photogain, but at the cost of response speed. Here, a rationally designed tunneling heterojunction fabricated by vertical stacking of non-layered In2 S3 and Te flakes is studied systematically. The Te/In2 S3 heterojunctions possess type-II band alignment and can transfer to type-I or type-III depending on the electric field applied, allowing for tunable tunneling of the photoinduced carriers. The Te/In2 S3 tunneling heterojunction exhibits a reverse rectification ratio exceeding 104 , an ultralow forward current of 10-12 A, and a current on/off ratio over 105 . A photodetector based on the heterojunctions shows an ultrahigh photoresponsivity of 146 A W-1 in the visible range. Furthermore, the devices exhibit a response time of 5 ms, which is two and four orders of magnitude faster than that of its constituent In2 S3 and Te. The simultaneously improved photocurrent and response speed are attributed to the direct tunneling of the photoinduced carriers, as well as a combined mechanism of photoconductive and photogating effects. In addition, the photodetector exhibits a clear photovoltaic effect, which can work in a self-powered mode.

Polarization-Resolved p-Se/n-WS2 Heterojunctions toward Application in Microcomputer System as Multivalued Signal Trigger.

Polarization-sensitive photodetectors based on van der Waals heterojunctions (vdWH) have excellent polarization-resolved optoelectronic properties that can enable the applications in polarized light identification and imaging. With the development of optical microcomputer control systems (OMCS), it is crucial and energy efficient to adopt the self-powered and polarization-resolved signal-generators to optimize the circuit design of OMCS. In this work, the selenium (Se) flakes with in-plane anisotropy and p-type character are grown and incorporated with n-type tungsten disulfide (WS2 ) to construct the type-II vdWH for polarization-sensitive and self-powered photodetectors. Under 405 nm monochrome laser with 1.33 mW cm-2 power density, the photovoltaic device exhibits superior photodetection performance with the photoelectric conversion efficiency (PCE) of 3.6%, the responsivity (R) of 196 mA W-1 and the external quantum efficiency (EQE) of about 60%. The strong in-plane anisotropy of Se crystal structure gives rise to the capability of polarized light detection with anisotropic photocurrent ratio of ≈2.2 under the 405 nm laser (13.71 mW cm-2 ). Benefiting from the well polarization-sensitive and photovoltaic properties, the p-Se/n-WS2 vdWH is successfully applied in the OMCS as multivalued signal trigger. This work develops the new anisotropic vdWH and demonstrates its feasibility for applications in logic circuits and control systems.

2D rigorous coupled wave analysis with adaptive spatial resolution for a multilayer periodic structure.

We utilize the 2D modal solution of rigorous coupled wave analysis with adaptive spatial resolution to enhance the reliability of standard RCWA for multilayer gratings with metal-dielectric structures. The conversion relation in modal solutions between the Cartesian system and the transformed system is for the first time established. Based on the proposed conversion relation, the modal solution of the metal-dielectric structure obtained in the transformed system can match the boundary conditions with modal solutions of other different grating layers in the Cartesian system. Numerical results show that even for metal patches in microwave band, the above method can still achieve good convergence and is perfectly suitable for multi-layer structure calculation.

Rigorous coupled wave analysis upgraded with combined boundary conditions method for 2D metamaterials in microwave.

We combine rigorous coupled wave analysis (RCWA) and combined boundary conditions method (CBCM) to analyze optical properties of two-dimensional periodic metamaterial grating with arbitrary shapes in microwave domain, and the adaptive spatial resolution (ASR) function is introduced to increase convergence especially for the crossed metamaterial gratings. The numerical results show that RCWA with CBCM can get the correct convergence result and distinguish the contribution of the grating lobes to the total transmission and reflection. The ASR technique improves dramatically the convergence speed of crossed grating. This method provides a more effective computational tool for the design of metamaterial grating in microwave domain.

Inhibiting nonhomologous end-joining repair would promote the antitumor activity of gemcitabine in nonsmall cell lung cancer cell lines.

Nonsmall cell lung cancer (NSCLC) is a major type of lung cancer. In current study, we aim to evaluate whether the combination of Ku70/80 heterodimer protein inhibitor STL127705 and gemcitabine would be more favorable approach for the treatment of NSCLC compared with monotreatment with gemcitabine. Clongenic survival assay was used to determine the survival and sensitivity to irradiation. H1299 was stained with fluorescein isothiocyanate-Annexin V, and cell apoptosis was measured by flow cytometry. H1299 cells were transfected with nonhomologous end-joining (NHEJ) repair reporter, and stable cell line was selected by puromycin. NHEJ activity was determined based on the intensity of green fluorescent protein. DNA double-strand breaks (DSBs) were determined by the fluorescence intensity of γH2AX using flow cytometry. The mRNA expressions of Ku70 and Ku80 were determined using quantitative real-time PCR. Combination of STL127705 enhanced sensitivity of NSCLC cell lines to irradiation when compared with treatment with gemcitabine alone. However, small cell lung cancer cell line was not affected. H1299 cells treated with STL127705 in combination with gemcitabine showed a significantly increased apoptosis compared with H1299 cells treated with gemcitabine alone. Moreover, STL127705 treatment dramatically reduced NHEJ activity in H1299 cells when compared with gemcitabine single treatment. Increased DSBs were consistently observed in H1299 when treated with the combination of STL127705 and gemcitabine. However, the mRNA levels of Ku70 and Ku80 were upregulated by the combination treatment. It demonstrated that STL127705 enhanced antitumor activity of gemcitabine. Mechanistically, treatment with STL127705 enhanced DNA damage via inhibiting NHEJ pathway, blocking DNA-PK, and forming Ku70/80 heterodimer, eventually leading to tumor cells apoptosis.

Multiple herbicide resistance in Eleusine indica from sugarcane fields in China.

Long-term reliance on herbicide weed control has led to resistance evolution in Eleusine indica in sugarcane fields of Guangxi Zhuang autonomous region. Ninety-six E. indica lines were collected from this region, and their response was tested to six herbicides: glyphosate; glufosinate; PSII-inhibitors diuron and atrazine; and PSI inhibitors paraquat and diquat. Target-site resistance mechanisms were examined in specific lines with multiple resistance to three herbicide modes of action. Of 96 E. indica lines, 51, 26, and 24 lines had resistance to diuron, atrazine, and diquat, respectively, while 14 and 9 had resistance to paraquat and glyphosate. Among 25 lines tested with multiple resistance, 7 lines exhibited resistance to three herbicide modes of action. In two multiple resistant lines (GXER2, GXER5), amplification/over-expression/mutations of the EPSPS gene contributed to the very high-level (up to 109-fold) glyphosate resistance. No target-site mutations/over-expression were identified in the psbA gene in these two lines, so non-target-site resistance mechanisms were likely responsible for the low-level (3-fold) resistance to the PSII herbicides diuron and atrazine. A high-level (23-fold) of paraquat resistance was observed in GXER5, and a low-level (5-fold) paraquat resistance was found in GXER2. Multiple herbicide resistance in E. indica has evolved in sugarcane fields of Guangxi Zhuang autonomous region with diverse resistance mechanisms. Therefore, diversified weed control tactics should be adopted to prevent this weed.

[Study on Impedance of Implantable Cardiac Pacemaker in Unipolar/Bipolar Pacing Mode by in Vitro Experiment].

The unipolar/bipolar pacing mode of pacemaker is related to its circuit impedance, which affects the battery life. In this study, the in vitro experiment scheme of pacemaker circuit impedance test was constructed. The human blood environment was simulated by NaCl solution, and the experimental environment temperature was controlled by water bath. The results of in vitro experiments showed that under the experimental conditions similar to clinical human parameters, the difference between the circuit impedance of bipolar mode and unipolar mode is 120~200 Ω. The results of the in vitro experiment confirmed that the circuit impedance of bipolar circuit was larger than that of unipolar mode, which was found in clinical practice. The results of this study have reference value to the optimization of pacing mode and the reduction of pacemaker power consumption.

CircPTK2-miR-181c-5p-HMGB1: a new regulatory pathway for microglia activation and hippocampal neuronal apoptosis induced by sepsis.

BACKGROUND: Circular RNA hsa_circ_0008305 (circPTK2), miR-181c-5p and High mobility group box-1 (HMGB1) had a targeted regulatory relationship through bioinformatics analysis. This study explained the effects of these genes in microglia and sepsis mice. METHODS: Lipopolysaccharide (LPS) or Cecal Ligation and Puncture (CLP) was used to induce inflammation cell model or sepsis mouse model, as needed. Gene levels were measured by enzyme linked immunosorbent assay (ELISA), quantitative real-time PCR or Western blot, as required. Apoptosis was detected by TUNEL assay, and RNase R was used to test the stability of circPTK2. Targeting relationships between genes were analyzed using bioinformatics analysis and dual luciferase assay. Morris water maze test and mitochondrial membrane potential (MMP) detection were conducted to analyze the effects of genes on cognitive dysfunction of mice. RESULTS: Lipopolysaccharide induction triggered the release of pro-inflammatory cytokines, the upregulation of HMGB1 and circPTK2, and the downregulation of miR-181c-5p in microglia. Overexpression of HMGB1 enhanced the effect of LPS, while silencing HMGB1 partially counteracted the effect of LPS. Moreover, miR-181c-5p was a target of circPTK2 and bound to HMGB1. MiR-181c-5p mimic partially reversed the functions of LPS and HMGB1 overexpression, reduced the levels of TNF-α, IL-1ß, and HMGB1, and inhibited apoptosis. CircPTK2 knockdown had the same effect as miR-181c-5p up-regulation. In vivo, sicircPTK2 improved cognitive function, restored MMP level, inhibited apoptosis, reduced the levels of inflammatory factors and apoptotic factors, and increased the survival rate of CLP-induced mice. CONCLUSION: Our research reveals that circPTK2 regulates microglia activation and hippocampal neuronal apoptosis induced by sepsis via miR-181c-5p-HMGB1 signaling.

Grain Boundary Design of Solid Electrolyte Actualizing Stable All-Solid-State Sodium Batteries.

Advanced inorganic solid electrolytes (SEs) are critical for all-solid-state alkaline metal batteries with high safety and high energy densities. A new interphase design to address the urgent interfacial stability issues against all-solid-state sodium metal batteries (ASSMBs) is proposed. The grain boundary phase of a Mg2+ -doped Na3 Zr2 Si2 PO12 conductor (denoted as NZSP-xMg) is manipulated to introduce a favorable Na3-2 δ Mgδ PO4 -dominant interphase which facilitates its intimate contact with Na metal and works as an electron barrier to suppress Na metal dendrite penetration into the electrolyte bulk. The optimal NZSP-0.2Mg electrolyte endows a low interfacial resistance of 93 Ω cm2 at room temperature, over 16 times smaller than that of Na3 Zr2 Si2 PO12 . The Na plating/stripping with small polarization is retained under 0.3 mA cm-2 for more than 290 days (7000 h), representing a record high cycling stability of SEs for ASSMBs. An all-solid-state NaCrO2 //Na battery is accordingly assembled manifesting a high capacity of 110 mA h g-1 at 1 C for 1755 cycles with almost no capacity decay. Excellent rate capability at 5 C is realized with a high Coulombic efficiency of 99.8%, signifying promising application in solid-state electrochemical energy storage systems.

Stimuli-Responsive Materials from Ferrocene-Based Organic Small Molecule for Wearable Sensors.

Stimuli-responsive crystals capable of energy conversion have emerged as promising materials for smart sensors, actuators, wearable devices, and robotics. Here, a novel ferrocene-based organic molecule crystal (Fc-Cz) that possesses anisotropic piezoelectric, optical, and mechanical properties is reported. It is demonstrated that the new crystal Fc-Cz can be used as an ultrasensitive piezoelectric material in fabricating strain sensors. The flexible sensor made of crystal Fc-Cz can detect small strains/deformations and motions with a fast response speed. Analysis based on density functional theory (DFT) indicates that an external pressure can affect the dipole moment by changing the molecular configuration of the asymmetric single crystal Fc-Cz in the crystalline state, leading to a change of polarity, and thereby an enhanced dielectric constant. This work demonstrates a new artificial organic small molecule for high-performance tactile sensors, indicating its great potential for developing low-cost flexible wearable sensors.