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Constructing a unipolar heterojunction is an effective energy band engineering strategy to improve the performance of photoelectric devices, which could suppress dark current and enhance detectivity by modulating the transfer of carriers. In this work, unipolar heterojunctions of Si/PbI2 and GaSb/PbI2 are constructed successfully for high-performance self-powered near-ultraviolet photodetection. Owing to the unique band offset of unipolar heterojunctions, the transport of holes is blocked, and only photogenerated electrons in PbI2 can flow unimpeded under the driving force of the built-in electric field. Thus, the recombination of photogenerated electron-hole pairs is suppressed, contributing to high-performance near-ultraviolet photodetection. The as-fabricated Si/PbI2 self-powered near-ultraviolet photodetector exhibits a low dark current of 10-13 A, a high Ilight/Idark ratio of 104, and fast response times of 26/24 ms, which are much better than those of the PbI2 metal-semiconductor-metal photodetector. Furthermore, the as-fabricated GaSb/PbI2 unipolar heterojunction photodetector also exhibits impressive self-powered near-ultraviolet photodetection behaviors. Evidently, this work shows the potential of unipolar heterojunctions for next-generation Si-based and GaSb-based high-performance photodetection.
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Due to their persistent photoconductivity, amorphous metal oxide thin films are promising for construction of artificial visual systems. In this work, large-scale, uniformly distributed amorphous InGaO thin films with an adjustable In/Ga ratio and thickness are prepared successfully by a low-cost environmentally friendly and easy-to-handle solution process for constructing artificial visual systems. With the increase of the In/Ga ratio and film thickness, the number of oxygen vacancies increases, along with the increase of post-synaptic current triggered by illumination, benefiting the transition of short-term plasticity to long-term plasticity. With an optimal In/Ga ratio and film thickness, the conductance response difference at a decay of 0 s between the 1st and the 10th views of a 5 × 5 array InGaO thin film transistor is up to 2.88 µA, along with an increase in the Idecay 30s/Idecay 0s ratio from 45.24% to 53.24%, resulting in a high image clarity and non-volatile artificial visual memory. Furthermore, a three-layer artificial vision network is constructed to evaluate the image recognition capability, exhibiting an accuracy of up to 91.32%. All results promise low-cost and easy-to-handle amorphous InGaO thin films for future visual information processing and image recognition.
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BACKGROUND: Insect pests have garnered increasing interest because of anthropogenic global change, and their sustainable management requires knowledge of population habitat use and spread patterns. To enhance this knowledge for the prevalent tea pest Empoasca onukii, we utilized a random forest algorithm and a bivariate map to develop and integrate models of its habitat suitability and genetic connectivity across China. RESULTS: Our modeling revealed heterogeneous spatial patterns in suitability and connectivity despite the common key environmental predictor of isothermality. Analyses indicated that tea cultivation in areas surrounding the Tibetan Plateau and the southern tip of China may be at low risk of population outbreaks because of their predicted low suitability and connectivity. However, regions along the middle and lower reaches of the Yangtze River should consider the high abundance and high recolonization potential of E. onukii, and thus the importance of control measures. Our results also emphasized the need to prevent dispersal from outside regions in the areas north of the Yangtze River and highlighted the effectiveness of internal management efforts in southwestern China and along the southeastern coast. Further projections under future conditions suggested the potential for increased abundance and spread in regions north of the Yangtze River and the southern tip of China, and indicated the importance of long-term monitoring efforts in these areas. CONCLUSION: These findings highlighted the significance of combining information on habitat use and spread patterns for spatially explicit pest management planning. In addition, the approaches we used have potential applications in the management of other pest systems and the conservation of endangered biological resources. © 2024 Society of Chemical Industry.
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This study describes a novel species of Diploderma (Squamata, Agamidae) from the lower valley of the Dadu River of the Sichuan Province of Western China based on its distinct morphological features and molecular evidence. D. daduense sp. nov. can be distinguished from its congeners by its tympanum concealed; head mainly green-yellow, supplemented by black; skin folds under the nuchal and dorsal crest obviously present in adult males only, its vertebral crest discontinuous between nuchal and dorsal sections with a distinct gap; transverse gular fold present but not obvious in some individuals; gular spot absent in both sexes; dorsolateral stripes green-yellow anteriorly, cyan in the center and blurry off-white posteriorly in adult males, the upper edge of dorsolateral stripes strongly jagged in adult males; no radial stripes around the eyes; inner-lip coloration smoky-white, and the coloration of the tongue and oral cavity as a light-flesh color in life; bright green-yellow transverse stripes on dorsal body in males; black patches are evenly distributed along the vertebral line between the dorsolateral stripes from the neck to the base of the tail in males; beech-brown or gray-brown line along the vertebral line with heart-shaped or diamond-shaped black patches on the dorsal body in females; and supratemporals fewer than four on at least one side. The phylogenetic tree based on mitochondrial ND2 sequences indicates that D. daduense sp. nov. forms an independent clade with strong support 1/100 in ML bootstrap/Bayesian posterior probability and is the sister group to D. splendidum. At the inter-species level, the p-distance is at least 6.95%, further confirming that an independent species had been identified. Our work raises the number of species within the genus Diploderma to 47.
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Amorphous In2O3 film is emerging as a promising oxide semiconductor for next-generation electronics and optoelectronics owing to high mobility and wide band gap. However, the persistent photocurrent phenomenon and high carrier concentration in amorphous In2O3 film are challenging the photodetection performances, resulting in a long response time and low Ilight/Idark ratio. In this work, the In2O3/PbI2 heterojunction is constructed by an all-solution synthesis process to inhibit the persistent photocurrent phenomenon and large dark current. Benefiting from the built-in electric field at the heterojunction interface, the In2O3/PbI2 heterojunction photodetector exhibits excellent self-powered photodetection performances with an ultralow dark current of 10-12 A, a high Ilight/Idark ratio of 104, and fast response times of 0.6/0.6 ms. Furthermore, the entire solution synthesis process and amorphous characteristics enable the fabrication of an In2O3/PbI2 heterojunction photodetector on arbitrary substrates to realize specific functions. When configured onto the polyimide substrate, the In2O3/PbI2 heterojunction photodetector shows excellent mechanical flexibility, bending endurance, and photoresponse stability. When implanted onto the transparent substrate, the In2O3/PbI2 heterojunction photodetector exhibits an outstanding omnidirectional self-powdered photodetection performance and imaging capability. All results pave the way for an all-solution-processed amorphous In2O3 film in advanced high-performance photodetectors.
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Owing to the Fermi pinning effect arose in the metal electrodes deposition process, metal-semiconductor contact is always independent on the work function, which challenges the next-generation optoelectronic devices. In this work, a metal-assisted transfer approach is developed to transfer Bi2 O2 Se nanosheets onto the pre-deposited metal electrodes, benefiting to the tunable metal-semiconductor contact. The success in Bi2 O2 Se nanosheets transfer is contributed to the stronger van der Waals adhesion of metal electrodes than that of growth substrates. With the pre-deposited asymmetric electrodes, the self-powered near-infrared photodetectors are realized, demonstrating low dark current of 0.04 pA, high Ilight /Idark ratio of 380, fast rise and decay times of 4 and 6 ms, respectively, under the illumination of 1310 nm laser. By pre-depositing the metal electrodes on polyimide and glass, high-performance flexible and omnidirectional self-powered near-infrared photodetectors are achieved successfully. This study opens up new opportunities for low-dimensional semiconductors in next-generation high-performance optoelectronic devices.
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AIMS: We investigated the real-world incidence of hypoglycemic events among patients with type 1 or type 2 diabetes (T1DM or T2DM) receiving insulin in routine clinical practice in China. METHODS: In this observational study, data were collected electronically via the Lilly Connected Care Program (LCCP) electronic system from adults with T1DM or T2DM who had registered on LCCP between 1 February 2019 and 31 January 2022, had used insulin for a full 12-week period following registration. The following outcomes were assessed during the 12 weeks following registration: incidence of level 1 and level 2 hypoglycemia. RESULTS: In total, 22,752 patients were enrolled. Among patients with monitoring data, over the 12-week study period, level 1 and 2 hypoglycemia were experienced by 48.8% and 25.9% of patients with T1DM and 26.5% and 13.9% of patients with T2DM. The proportion of patients treated with oral anti-diabetes drugs (OADs) capable of producing hypoglycemia (sulfonylurea or glinide) was 1.3% in T1DM and 1.6% in T2DM, respectively. Questionnaire data revealed that up to 92.5% of hypoglycemic events occurred outside of hospital and 18.6% were serious. CONCLUSIONS: These real-world data collected from Chinese patients with diabetes receiving insulin treatment reveal a relatively high percentage of patients experiencing hypoglycemia, with around one quarter of these events classified as severe and as many as 92.5% occurring outside of a hospital or clinic.
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Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Hipoglucemia , Adulto , Humanos , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/epidemiología , Diabetes Mellitus Tipo 2/epidemiología , Incidencia , Hipoglucemia/inducido químicamente , Hipoglucemia/epidemiología , Hipoglucemia/tratamiento farmacológico , Hipoglucemiantes/efectos adversos , Factores de Riesgo , Insulina/efectos adversos , Insulina Regular Humana/uso terapéutico , China/epidemiologíaRESUMEN
Growing high-quality core-shell heterostructure nanowires is still challenging due to the lattice mismatch issue at the radial interface. Herein, a versatile strategy is exploited for the lattice-mismatch-free construction of III-V/chalcogenide core-shell heterostructure nanowires by simply utilizing the surfactant and amorphous natures of chalcogenide semiconductors. Specifically, a variety of III-V/chalcogenide core-shell heterostructure nanowires are successfully constructed with controlled shell thicknesses, compositions, and smooth surfaces. Due to the conformal properties of obtained heterostructure nanowires, the wavelength-dependent bi-directional photoresponse and visible light-assisted infrared photodetection are realized in the type-I GaSb/GeS core-shell heterostructure nanowires. Also, the enhanced infrared photodetection is found in the type-II InGaAs/GeS core-shell heterostructure nanowires compared with the pristine InGaAs nanowires, in which both responsivity and detectivity are improved by more than 2 orders of magnitude. Evidently, this work paves the way for the lattice-mismatch-free construction of core-shell heterostructure nanowires by chemical vapor deposition for next-generation high-performance nanowire optoelectronics.
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The inhomogeneous native oxide shells on the surfaces of III-V group semiconductors typically yield inferior and unstable electrical properties metrics, challenging the development of next-generation integrated circuits. Herein, the native GaOx shells are profitably utilized by a simple in-situ thermal annealing process to achieve high-performance GaSb nanowires (NWs) field-effect-transistors (FETs) with excellent bias-stress stability and synaptic behaviors. By an optimal annealing time of 5 min, the as-constructed GaSb NW FET demonstrates excellent stability with a minimal shift of transfer curve (ΔVth ≈ 0.54 V) under a 60 min gate bias, which is far more stable than that of pristine GaSb NW FET (ΔVth ≈ 8.2 V). When the high bias-stress stability NW FET is used as the chargeable-dielectric free synaptic transistor, the typical synaptic behaviors, such as short-term plasticity, long-term plasticity, spike-time-dependent plasticity, and reliable learning stability are demonstrated successfully through the voltage tests. The mobile oxygen ion in the native GaOx shell strongly offsets the trapping states and leads to enhanced bias-stress stability and charge retention capability for synaptic behaviors. This work provides a new way of utilizing the native oxide shell to realize stable FET for chargeable-dielectric free neuromorphic computing systems.
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Cost-effective fabrication of mechanically flexible low-power electronics is important for emerging applications including wearable electronics, artificial intelligence, and the Internet of Things. Here, solution-processed source-gated transistors (SGTs) with an unprecedented intrinsic gain of ~2,000, low saturation voltage of +0.8 ± 0.1 V, and a ~25.6 µW power consumption are realized using an indium oxide In2O3/In2O3:polyethylenimine (PEI) blend homojunction with Au contacts on Si/SiO2. Kelvin probe force microscopy confirms source-controlled operation of the SGT and reveals that PEI doping leads to more effective depletion of the reverse-biased Schottky contact source region. Furthermore, using a fluoride-doped AlOx gate dielectric, rigid (on a Si substrate) and flexible (on a polyimide substrate) SGTs were fabricated. These devices exhibit a low driving voltage of +2 V and power consumption of ~11.5 µW, yielding inverters with an outstanding voltage gain of >5,000. Furthermore, electrooculographic (EOG) signal monitoring can now be demonstrated using an SGT inverter, where a ~1.0 mV EOG signal is amplified to over 300 mV, indicating significant potential for applications in wearable medical sensing and human-computer interfacing.
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Inteligencia Artificial , Conducción de Automóvil , Humanos , Dióxido de Silicio , Suministros de Energía Eléctrica , Óxidos , PolietileneiminaRESUMEN
The Source Area of the Yellow River (SAYR) on the Northeastern Qinghai-Tibet Plateau (QTP) stores substantial amounts of ground ice, which plays a significant role in understanding the hydrological processes and past permafrost evolution on the QTP. However, little is known about the initial sources and controlling factors of the ground ice in the SAYR. In this study, for the first time, ground ice stable isotope data (δ18O, δD, and d-excess) are presented, along with cryostratigraphic information for nine sites is integrated into three cryostratigraphic units (palsa, thermo-gully, and lake-affected sites) in the central SAYR. The ground ice in the nine sites exhibited diverse structures, ice contents, and stable isotopes due to differences in the initial water sources, ice formation mechanisms, soil types, and climate conditions. All of the freezing lines of ground ice are below those of the precipitation, streams, and lakes in most cases, suggesting the freezing of liquid water. The near-surface ground ice (NSGI) originated from precipitation, active layer water, and precipitation-fed springs. The NSGI was formed by quick freezing at the thermo-gully site (TG-1). In contrast, the formation of the NSGI at the palsa site (Palsa-1) experienced a slow segregation process during the permafrost aggradation. The NSGI was formed by quick freezing at the lake-affected sites under colder climate conditions. Conversely, the deep-layer ground ice (DLGI) at the lake-affected sites was fed by isotopically negative water and lake water occurred during a colder climate period. The DLGI at the TG-1 and Palsa-1 formed via similarly slow segregation of supra-permafrost water (mixed with precipitation), but had opposite water migration directions. The stable isotope compositions of the DLGI at the lake-affected sites became gradually more positive with decreasing distance from WL Lake, emphasizing the large influence of the lake changes on the growth of ice. The two end-member mixing model estimated that the contributions of paleo-lake water to the DLGI ranged from 9.8 % to 63.4 % towards the lake at the lake-affected sites, while the meltwater from past permafrost/ground ice contributed 36.6-90.2 % of the total input. A conceptual diagram of the δ18O trajectories of ground ice was constructed, the water migration patterns and ground ice formation processes between the palsa, thermo-gully, and lake-affected sites were clarified. The results of this study emphasize the influence of lake changes and past permafrost evolution on ground ice growth and improve our understanding of permafrost changes on the QTP.
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INTRODUCTION: We explored whether visceral fat accumulation mediates the development of hepatic steatosis in individuals living with overweight and obesity. METHODS: This cross-sectional study enrolled 769 outpatients with overweight and obesity aged 18-65 years. The controlled attenuation parameter (CAP) was used to quantify the degree of hepatic steatosis. Visceral fat accumulation, represented by the visceral fat area (VFA), was measured using magnetic resonance imaging. The associations of body mass index (BMI), VFA, and CAP with each other were assessed by univariate analysis, multivariate linear regression, and mediation analysis, respectively. RESULTS: Compared with women, male subjects had higher BMI, VFA, and CAP levels. In both sex, CAP was positively correlated with BMI and VFA by the univariate analysis. After adjusting for demographic and serum characteristics, the linear correlation coefficients between BMI and CAP were 1.738 (95% confidence interval (CI): 1.100, 2.377), 1.524 (95% CI: 0.798, 2.249), and 2.650 (95% CI: 1.292, 4.009) in all subjects, females, and males, respectively, while those between VFA and CAP were 0.190 (95% CI: 0.133, 0.247), 0.184 (95% CI: 0.117, 0.252), and 0.194 (95% CI: 0.086, 0.301). Mediation analysis showed that visceral fat accumulation contributed to 51.37%, 53.85%, and 26.51% of obesity-induced hepatic steatosis in the total, female, and male subjects, respectively. CONCLUSION: Visceral fat accumulation partially mediates obesity-induced hepatic steatosis in individuals with overweight and obesity, especially in women. More focus on visceral fat reduction is needed in individuals with obesity.
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Hígado Graso , Sobrepeso , Humanos , Masculino , Femenino , Sobrepeso/complicaciones , Estudios Transversales , Grasa Intraabdominal/diagnóstico por imagen , Grasa Intraabdominal/patología , Obesidad/complicaciones , Obesidad/patología , Hígado Graso/complicaciones , Hígado Graso/diagnóstico por imagenRESUMEN
Power consumption makes next-generation large-scale photodetection challenging. In this work, the source-gated transistor (SGT) is adopted first as a photodetector, demonstrating the expected low power consumption and high photodetection performance. The SGT is constructed by the functional sulfur-rich shelled GeS nanowire (NW) and low-function metal, displaying a low saturated voltage of 0.61 V ± 0.29 V and an extremely low power consumption of 7.06 pW. When the as-constructed NW SGT is used as a photodetector, the maximum value of the power consumption is as low as 11.96 nW, which is far below that of the reported phototransistors working in the saturated region. Furthermore, benefiting from the adopted SGT device, the photodetector shows a high photovoltage of 6.6 × 10-1 V, a responsivity of 7.86 × 1012 V W-1, and a detectivity of 5.87 × 1013 Jones. Obviously, the low power consumption and excellent responsivity and detectivity enabled by NW SGT promise a new approach to next-generation, high-performance photodetection technology.
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Realizing omnidirectional self-powered photodetectors is central to advancing next-generation portable and smart photodetector systems. However, the traditional omnidirectional photodetector is typically achieved by integrating complex hemispherical microlens on multiple photodetectors, which makes the detection system cumbersome and restricts its application in the portable field. Here, facile and high-performance flexible omnidirectional self-powered photodetectors are achieved by solution-processed two-dimensional (2D) layered PbI2 nanoplates on transparent conducting substrates. Characterization of PbI2 nanoplates microstructural/compositional and their photodetection properties have been systematically characterized. Under the irradiation of a 405 nm laser, the photodetectors exhibit an impressively low dark current of 10-13 A, a high light on/off ratio up to 106, and a fast rise/decay response time of 2/3 ms. Importantly, when light irradiates the photodetector at 5°, it can still maintain high photodetection properties, realizing almost 360° omnidirectional self-powered photodetection. What is more, these self-powered photodetectors exhibit robust omnidirectional photoresponse stability of flexibility even after bending for 1200 cycles. Thus, this work broadens the applicability of 2D layered nanoplates for further extending its applications in advanced optoelectronic devices.
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Bacteria of the cryptic lineage of genus Escherichia, or Escherichia cryptic clades (cryptic clades), are phenotypically indistinguishable from Escherichia coli (E. coli) using standard biochemical tests. Except for clade I (C-I), cryptic clades were hypothetically believed to be environmental but not enteric. If so, they would hinder the interpretation of current E. coli-based water quality (fecal pollution) monitoring in the United States because environmental bacteria do not indicate the presence of harmful fecal material. This study was performed to develop a rapid method for the detection of cryptic clades and to investigate their potential impact on water quality monitoring. By whole-genome comparison, one gene, named ecc (Escherichiacryptic clades), was identified to be unique to C-II through C-VIII. An end-point polymerase chain reaction (PCR) method, eccPCR, was developed by targeting the ecc. The results of in-silico and wet tests demonstrated 100 % sensitivity and specificity of the eccPCR to detect C-II through C-VIII. Based on the EPA Method 1603, 519 presumptive E. coli isolates were obtained from the fecal samples of 13 different host species and 192 isolates from surface water samples taken at four locations in a watershed of mid-Missouri. As indicated by the eccPCR amplification, the overall prevalence of C-II through C-VIII in the presumptive E. coli isolates was estimated to be about 0.6 % in the fecal samples and about 1.6 % in the water samples. Therefore, the potential impact of cryptic clades on water quality monitoring may be limited if EPA Method 1603 is used. Furthermore, clades C-II through C-VIII in stream water samples were found repeatedly only at a single sampling site, but neither at the upstream sites nor five kilometers downstream of the site. The data do not support nor reject the environmental hypothesis about cryptic clades. Further study is needed to determine the implication of the observation.
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Infecciones por Escherichia coli , Escherichia coli , Bacterias , Monitoreo del Ambiente/métodos , Heces/microbiología , Humanos , Prevalencia , Contaminación del Agua , Calidad del AguaRESUMEN
Highly ordered semiconducting single-walled carbon nanotubes(sc-SWCNTs) array with high purity, high linear density and controllable manner is strongly desired for carbon-based integrated circuits, yet it remains a big challenge. Herein, close-packed single layered and controllably aligned sc-SWCNTs arrays were obtained through dielectrophoresis using a high purity sc-SWCNT dispersion. Under optimized condition of length and average number of interconnecting junctions across the channel full of aligned sc-SWCNTs, field effect transistors (FETs) with high performance were achieved with both a high on/off current ratio and large carrier mobility. Based on the optimized channel length, by systematically optimizing the dielectrophoresis parameters of the frequency and duration of applied AC voltage (Vpp), the highly ordered sc-SWCNTs arrays with an ultra-high linear density of 54 ± 2 tubesµm-1showed relatively high device performance of FET. The fabrication process optimized in this report can be further extended and applied in large-area, low-cost carbon-based integrated circuits.