Developing and validating the nurse-patient relationship scale (NPRS) in China.

BACKGROUND: Poor nurse-patient relationship poses an obstacle to care delivery, jeopardizing patient experience and patient care outcomes. Measuring nurse-patient relationship is challenging given its multi-dimensional nature and a lack of well-established scales. PURPOSE: This study aimed to develop a multi-dimensional scale measuring nurse-patient relationship in China. METHODS: A preliminary scale was constructed based on the existing literature and Delphi consultations with 12 nursing experts. The face validity of the scale was tested through a survey of 45 clinical nurses. This was followed by a validation study on 620 clinical nurses. Cronbach's α, content validity and known-group validity of the scale were assessed. The study sample was further divided into two for Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA), respectively, to assess the construct validity of the scale. RESULTS: The Nurse-Patient Relationship Scale (NPRS) containing 23 items was developed and validated, measuring five dimensions: nursing behavior, nurse understanding and respect for patient, patient misunderstanding and mistrust in nurse, communication with patient, and interaction with patient. The Cronbach's α of the NPRS ranged from 0.725 to 0.932, indicating high internal consistency. The CFA showed excellent fitness of data into the five-factor structure: χ2/df = 2.431, GFI = 0.933, TLI = 0.923, CFI = 0.939, IFI = 0.923, RMSEA = 0.070. Good content and construct validity are demonstrated through expert consensus and psychometric tests. CONCLUSION: The NPRS is a valid tool measuring nurse-patient relationship in China.

A Modular and Cost-Effective Droplet Microfluidic Device for Controlled Emulsion Production.

The droplet microfluidic device has become a widely used tool in fields such as physics, chemistry, and biology, but its complexity has limited its widespread application. This report introduces a modular and cost-effective droplet microfluidic device for the controlled production of complex emulsions, including oil and aqueous single emulsions, and double emulsions with varying numbers of encapsulated droplets. The droplet sizes can be precisely controlled by easily replacing flat needles and adjusting the needle position within an axially accelerated co-flow field. This modular device not only allows for easy repair and maintenance in case of device clogging or damage but can also be readily expanded to produce complex emulsions. The low-cost and user-friendly nature of the device greatly facilitates the widespread adoption and utilization of droplet microfluidics.

Photosynthetic-Membrane-Like Ion Translocation in Visible-Light-Harvesting Nanofluidic Channels.

The selective uphill and downhill movement of protons in and out of photosynthetic membrane enabled by ion pumps and ion channels is key to photosynthesis. Reproducing the functions of photosynthetic membranes in artificial systems has been a persistent goal. Here, a visible-light-harvesting nanofluidic channels is reported which experimentally demonstrates the ion translocation functions of photosynthetic membranes. A molecular junction consisting of photosensitive ruthenium complexes linked to TiO2 electron acceptors forms the reaction centers in the nanofluidic channels. The visible-light-triggered vectorial electron injection into TiO2 establishes a difference in transmembrane potential across the channels, which enables uphill transport of ions against a 5-fold concentration gradient. In addition, the asymmetric charge distribution across the channels enables the unidirectional downhill movement of ions, demonstrating an ion rectification effect with a ratio of 18:1. This work, for the first time, mimics both the uphill and downhill ion translocation functions of photosynthetic membranes, which lays a foundation for nanofluidic energy conversion.

Emotional labour and turnover intention among nurses in China: Mediating effects of nurse-patient relationship and self-rated health.

AIM: This study tested the mediating role of the nurse-patient relationship and self-rated health in the effect of emotional labour on turnover intention among nurses in China. BACKGROUND: The underlying mechanism behind the effect of emotional labour on turnover intention remains inadequately understood. INTRODUCTION: Nurses with a high level of emotional labour are predisposed to experiencing poor health and tension in their relationships with patients, which may increase turnover intention. METHODS: A cross-sectional survey of 527 nurses in a public tertiary hospital in Qiqihar, located in China's Heilongjiang province, was conducted. Emotional labour and turnover intention were assessed using existing validated scales containing multiple items, while the nurse-patient relationship and self-rated health were assessed using single items, respectively. Baron and Kenny's causal steps and the Karlson/Holm/Breen method were adopted to test the mediating effects of the nurse-patient relationship and self-rated health in the association between emotional labour and turnover intention after adjusting for variations in sociodemographic and job characteristics. RESULTS: Emotional labour was positively associated with turnover intention. Self-rated poor health and a disharmonious nurse-patient relationship partially mediated the positive effect of emotional labour on turnover intention. CONCLUSIONS: Emotional labour significantly affects the turnover intention of nurses working in public tertiary hospitals in China, and this effect is partially mediated by self-rated health and the nurse-patient relationship. IMPLICATIONS FOR NURSING PRACTICE AND NURSING POLICY: Giving more attention to nurses' negative emotions and work attitudes is crucial. Developing comprehensive strategies for enhancing nurses' emotional management ability, promoting their physical and psychological well-being, and improving nurse-patient relationship to reduce nurses' turnover.

[Source Apportionment and Potential Ecological Risk Assessment of Soil Heavy Metals in Typical Industrial and Mining Towns in North China].

To understand the status of heavy metals in soils of typical industrial and mining towns and quantitatively analyze the potential sources, the contents of seven heavy metals (Cd, As, Pb, Cr, Cu, Ni, and Zn) in 150 surface soils in Xuanhua District, Zhangjiakou City, Hebei Province were collected and examined. The geoaccumulation index and potential ecological risk index methods were used to evaluate the heavy metal pollution status and potential ecological risk. Principal component analysis (PCA) and the positive matrix factorization (PMF) model were used to comprehensively analyze the pollution sources of seven heavy metals, and geostatistics was used to identify the high contribution areas of potential sources. The results revealed that:① the average values of heavy metals in the study area ranged from 0.23-103.34 mg·kg-1, among which the average contents of Cd, Pb, Cu, and Zn were higher than the soil background value of Hebei Province. ② The results of the geoaccumulation and potential ecological risk indices demonstrated that the degree of pollution of the seven heavy metals was in the following order:Cd>Pb>Cu>Zn>Ni>As>Cr, the content of Cd in 16% sites was above a moderate pollution level, and the potential ecological risk of heavy metals in more than 95% sites was at a light risk level. ③ The main sources of accumulation of the seven heavy metals in the study area were combined sources of industry and traffic, natural sources, and agricultural sources, with their contribution rates of 33.1%, 48.7%, and 18.2%, respectively. Among them, Cd, Pb, Cu, and Zn were primarily affected by the combined sources of industry and transportation; Cr, Ni, and As were mainly affected by natural sources, whereas Cd and some As were affected by agricultural sources. The organic combination of PCA, PMF model, and geostatistical methods confirmed the results of each analysis, which increased the reliability of the analytical results of heavy metal sources.

Factors influencing nurse fatigue during COVID-19: regression vs. fuzzy-set qualitative comparative analysis.

Background: Nurses during COVID-19 who face significant stress and high infection risk are prone to fatigue, affecting their health and quality of patient care. A cross- sectional study of 270 nurses who went to epidemic area to support anti-epidemic was carried out via online survey during the COVID-19 pandemic on November 2021. Methods: A web-based cross-sectional survey of 270 nurses in China who traveled to Heihe City in Heilongjiang Province to combat the novel coronavirus epidemic. The researchers collected information on sociodemographic variables, anxiety, transition shock, professionalism, collaboration, hours of work per day, and fatigue. Regression and fuzzy-set Quality Comparative Analysis (fsQCA) evaluated the factors' impact on the nurses' fatigue. Results: Regression analysis showed that the psychological variables significant for fatigue, transition shock (ß = 0.687, p < 0.001) and anxiety (ß = 0.757, p < 0.001) were positively associated with fatigue, professionalism (ß = -0.216, p < 0.001) was negatively associated with fatigue, and among the work-related variables, cooperation (ß = -0.262, p < 0.001) was negatively related to fatigue. FsQCA analysis showed that combined effects of work hours, anxiety, and nurses' educational status caused most of the fatigue (raw coverage = 0.482, consistency = 0.896). Conclusion: This study provides two main findings, the one is the greater transition shock experienced during COVID-19 in a new environment, low levels of professionalism, anxiety, and poor nursing teamwork situations lead anti-epidemic nurses to increased fatigue. Second, the fsQCA results showed that anxiety is sufficient for fatigue and that nurses' educational status, daily working hours, and anxiety are the most effective combination of factors.

Anxiety and Insomnia Mediate the Association of Fear of Infection and Fatigue: A Cross-Sectional Survey of Nurses Deployed to a COVID-19 Epicenter in China.

Background: This study aimed to test the mediating role of anxiety and insomnia in the association between fear of infection and fatigue. Methods: A cross-sectional questionnaire survey was conducted on the nurses deployed to Heihe. A serial multiple mediation model was established to determine the role of anxiety and insomnia in the association between fear of infection and fatigue. Findings: Over half (53.0%) of the study participants reported experiencing fear of infection despite stringent personal protection measures. The scores of anxiety (11.87±5.19), insomnia (16.33±5.95), and fatigue (45.94±12.93) were moderately correlated, with a Pearson correlation coefficient ranging from 0.501 to 0.579. Anxiety, either alone or in combination with insomnia, mediated the association between fear of infection and fatigue. Conclusion: The findings suggest that anxiety and insomnia play a mediating role in the relationship between fear of infection and fatigue. These results emphasize the importance of implementing targeted mental health interventions and work arrangements to address the well-being of healthcare professionals.

Application of 3D Bioprinting in Liver Diseases.

Liver diseases are the primary reason for morbidity and mortality in the world. Owing to a shortage of organ donors and postoperative immune rejection, patients routinely suffer from liver failure. Unlike 2D cell models, animal models, and organoids, 3D bioprinting can be successfully employed to print living tissues and organs that contain blood vessels, bone, and kidney, heart, and liver tissues and so on. 3D bioprinting is mainly classified into four types: inkjet 3D bioprinting, extrusion-based 3D bioprinting, laser-assisted bioprinting (LAB), and vat photopolymerization. Bioinks for 3D bioprinting are composed of hydrogels and cells. For liver 3D bioprinting, hepatic parenchymal cells (hepatocytes) and liver nonparenchymal cells (hepatic stellate cells, hepatic sinusoidal endothelial cells, and Kupffer cells) are commonly used. Compared to conventional scaffold-based approaches, marked by limited functionality and complexity, 3D bioprinting can achieve accurate cell settlement, a high resolution, and more efficient usage of biomaterials, better mimicking the complex microstructures of native tissues. This method will make contributions to disease modeling, drug discovery, and even regenerative medicine. However, the limitations and challenges of this method cannot be ignored. Limitation include the requirement of diverse fabrication technologies, observation of drug dynamic response under perfusion culture, the resolution to reproduce complex hepatic microenvironment, and so on. Despite this, 3D bioprinting is still a promising and innovative biofabrication strategy for the creation of artificial multi-cellular tissues/organs.

Research on health risk assessment of heavy metals in soil based on multi-factor source apportionment: A case study in Guangdong Province, China.

Environmental problems caused by heavy metal pollution in soil have attracted widespread attention worldwide. Identifying and quantifying the heavy metal pollution sources and risks is crucial for subsequent soil management. In this study, an integrated source-risk method for source apportionment and risk assessment based on the PMF model, the geodetector model and the health risk assessment model (HRA) was proposed and applied. Analysis of Hg, As, Pb, Cd, Cu, Ni, Cr, and Zn in 208 topsoils showed that the average contents of eight heavy metals were 1.87-5.86 times greater than corresponding background values, among which Cd and As were relatively high, which were higher than the specified soil risk screening values, high-value areas of heavy metals are mainly concentrated in the central part of the study area. The source apportionment showed that the accumulation of heavy metals was affected by five sources: atmospheric deposition (16.3 %), natural sources (33.1 %), industrial activities dominated by metal mining (15.1 %), industrial activities dominated by metal smelting (12.6 %) and traffic sources (22.9 %). The results of the health risk assessment showed that the carcinogenic risks (adult: 4.74E-05, children: 7.41E-05) of heavy metals in soil to the study population were both acceptable, the non-carcinogenic risk of adult (THI = 0.277) was within the limit, while the non-carcinogenic risk of children (THI = 1.70) was higher than the limit value. Ingestion (89.5 %-95.9 %) contributed the greatest health risk among all exposure routes. Source 3 (arsenic-related industrial activities dominated by metal mining) contributed the most to the HI and CRI of adults and children (all above 50 %), therefore, in the formulation stage of soil management strategy in this area, priority should be given to the control and management of this pollution source. These results can provide more detailed support for environmental protection departments to propose targeted soil pollution control measures.

Film mulching alters soil properties and increases Cd uptake in Sedum alfredii Hance-oil crop rotation systems.

Film mulching (FM) is an agronomic measure worldwide, yet its effect on cadmium (Cd) accumulation in plants is unknown. This study investigated the potential for phytoremediation with FM treatment of Cyperus esculentus L. (chufa) and Sedum alfredii Hance (S. alfredii)-oil crop rotation system. The FM increased the biomass and Cd content of the chufa, resulting in an increase of 65.0-193.5% in the Cd accumulation. S. alfredii also was planted using non-film mulching and film mulching (FMSA), followed by rotation oil plants using non-film mulching. Soil pH and dissolved organic carbon content were significantly reduced, and the Cd grain size fraction of macro-aggregates was significantly increased by FMSA, which increased the uptake of available Cd by S. alfredii. This phenomenon further promoted the accumulation of Cd in S. alfredii and reduced the Cd content of aboveground tissues and seeds in subsequent oil crops. Vegetable oils were safely produced in all treatments due to their low Cd content. Compared with non-film mulching, FM increased the Cd accumulation of rotation systems by 66.8-96.4%, and the Cd remediation efficiency reached 11.8-12.9%. Collectively, the FM treatment effectively improved the remediation efficiency of Cd in the rotation system and ensured the safe production of vegetable oil.

Structural Design of Ocean Temperature and Depth Sensor with Quick Response and High Sensitivity.

The electrical sensing elements used in the traditional XBT (Expendable Bathythermograph) have problems such as low sensitivity and slow response time, and it is difficult to overcome the complex marine environment using the time-depth formula. In this paper, an ocean temperature depth sensor based on brass diaphragm and liquid filling is designed. The stress response time of FBGs with different lengths and the heat transfer time of different liquid materials are compared, and it is found that a fast response of 51 ms can be obtained by using GaInSn liquid for temperature sensing. The center deflection changes of brass diaphragms with different radii are analyzed, and the brass diaphragms with radius and thickness of 10 mm and 1 mm are selected, which still have good elastic properties under the pressure of 5 MPa. The influence of the inner metal shell section radius on the temperature and depth sensitivity is analyzed. When the final section radius is 3 mm, the temperature sensitivity of the sensor is 1.065 nm/°C, the pressure sensitivity is 1.245 nm/MPa, and the response time of temperature and depth is relatively close. Compared with the traditional temperature and depth sensors using empirical formulas for calculation, the data accuracy is improved, and a wide range of sensitivity can be tuned by adjusting the size of the internal metal shell, which can meet the needs of ocean temperature and depth data detection with high sensitivity and fast response time.

Expression and Significance of D-Dimer and Fibrinogen in Hyperfibrinolysis of Elderly Patients with Bleeding after BPH Operation.

Objective: To explore the expression level and diagnostic efficacy of plasma D-dimer (DD) and fibrinogen (FIB) in hyperfibrinolysis of elderly patients with bleeding after benign prostatic hyperplasia (BPH) surgery. Methods: 70 elderly BPH patients with postoperative hemorrhage and hyperfibrinolysis in our hospital were included into the observation group, and 75 elderly BPH patients with postoperative hemorrhage without hyperfibrinolysis were included into the control group. The serum levels of DD and FIB in the two groups of patients were compared, and the correlation of DD and FIB with clinical features and the diagnostic value of DD and FIB. Results: Elderly BPH patients with hyperfibrinolysis showed significantly higher levels of DD and FIB than those without hyperfibrinolysis (P < 0.01). The increase in DD and the decrease of FIB were significantly correlated with the prolonged hospital stay and intensive care unit (ICU) monitoring (P < 0.05). The combination of DD and FIB showed high diagnostic value for postoperative hemorrhage with hyperfibrinolysis (AUC = 0.998). Conclusion: The combination of plasma DD and FIB effectively and accurately diagnoses postoperative hemorrhage with hyperfibrinolysis. High levels of DD and FIB indicate prolonged hospital stay and postoperative ICU monitoring of elderly BPH patients with hyperfibrinolysis.

Cation-Selective Oxide Semiconductor Mesoporous Membranes for Biomimetic Ion Rectification and Light-Powered Ion Pumping.

Artificial membranes precisely imitating the biological functions of ion channels and ion pumps have attracted significant attention to explore nanofluidic energy conversion. Herein, inspired by the cyclic ion transport for the photosynthesis in purple bacteria, a bilayer inorganic membrane (TiO2 /AAO) composed of oxide semiconductor (TiO2 ) mesopores on anodic alumina (AAO) macropores is we developed. This inorganic membrane achieves the functions of ion channels and ion pumps, including the ion rectification and light-powered ion pumping. The asymmetric charge distribution across the bilayer membrane contributes to the cationic selectivity and ion rectification characteristics. The electrons induced by ultraviolet irradiation introduce a built-in electric field across TiO2 /AAO membrane, which pumps the active ion transport from a low to a high concentration. This work integrates the functions of biological ion channels and ion pumps within an artificial membrane for the first time, which paves the way to explore multifunctional membranes analogous to its biological counterpart.

Design of a Fiber Bragg Grating Pressure Sensor Based on a Metal Diaphragm and Lever Structure.

In this paper, a pressure sensor based on a metal diaphragm and lever structure is designed, the sensing principle and mechanical structure of this sensor are analyzed and simulated, and its sensitization effectiveness and temperature compensation are verified. The maximum deflections of metal diaphragms of different sizes and materials were compared, and it was found that the square beryllium bronze diaphragm with a thickness of 1 mm and a side length of 20 mm had good elastic properties. The influence of the FBG in different positions of the lever on the center wavelength is analyzed. The sensitivity of the bare FBG is markedly improved under the influence of the two structures of the square elastic diaphragm and the lever, with a typical pressure sensitivity of 3.35 nm/MPa at 3 mm to the left of the lever center. The purpose of temperature compensation is achieved by adding another FBG that measures the temperature, and the sensing sensitivity can be tuned by adjusting the position of the FBG. It can meet the detection needs of a small range and high sensitivity.

Analysis of Risk Factors and Nursing Strategies for Postoperative Hemorrhage of Benign Prostatic Hyperplasia.

This study is to investigate the risk factors analysis and nursing strategies for postoperative bleeding of benign prostatic hyperplasia (BPH). Totally, 240 BPH patients after surgical excision admitted to Hengshui People's Hospital between January 2019 and January 2020 were recruited. Of the 240 BPH patients, 20 had postoperative bleeding, accounting for 8.3% of all enrollments. Risk factors for postoperative bleeding included large prostate, diabetes, hypertension, urinary tract infection within 1 week before surgery, and the absence of epidural analgesia pumps. There were 87 patients receiving routine nursing (routine group) and 153 patients receiving routine nursing plus hemorrhage prevention care (study group). The study group had fewer cases of postoperative bleeding than the routine group. The influencing factors of postoperative bleeding in patients with prostatic hyperplasia include systemic and local factors, and corresponding hemorrhage prevention care should be performed based on the principle of evidence-based care to reduce the risk of postoperative bleeding.

Continuous g-C3N4 layer-coated porous TiO2 fibers with enhanced photocatalytic activity toward H2 evolution and dye degradation.

TiO2/g-C3N4 composite photocatalysts with various merits, including low-cost, non-toxic, and environment friendliness, have potential application for producing clean energy and removing organic pollutants to deal with the global energy shortage and environmental contamination. Coating a continuous g-C3N4 layer on TiO2 fibers to form a core/shell structure that could improve the separation and transit efficiency of photo-induced carriers in photocatalytic reactions is still a challenge. In this work, porous TiO2 (P-TiO2)@g-C3N4 fibers were prepared by a hard template-assisted electrospinning method together with the g-C3N4 precursor in an immersing and calcination process. The continuous g-C3N4 layer was fully packed around the P-TiO2 fibers tightly to form a TiO2@g-C3N4 core/shell composite with a strong TiO2/g-C3N4 heterojunction, which greatly enhanced the separation efficiency of photo-induced electrons and holes. Moreover, the great length-diameter ratio configuration of the fiber catalyst was favorable for the recycling of the catalyst. The P-TiO2@g-C3N4 core/shell composite exhibited a significantly enhanced photocatalytic performance both in H2 generation and dye degradation reactions under visible light irradiation, owing to the specific P-TiO2@g-C3N4 core/shell structure and the high-quality TiO2/g-C3N4 heterojunction in the photocatalyst. This work offers a promising strategy to produce photocatalysts with high efficiency in visible light through a rational structure design.

Light-Powered Ion Pumping in a Cation-Selective Conducting Polymer Membrane.

The simulation of the ion pumping against a proton gradient energized by light in photosynthesis is of significant importance for the energy conversion in a non-biological environment. Herein, we report light-powered ion pumping in a polystyrene sulfonate anion (PSS) doped polypyrrole (PPy) conducting polymer membrane (PSS-PPy) with a symmetric geometry. This PSS-PPy conducting polymer membrane exhibits a cationic selectivity and a light-responsive surface-charge-governed ion transport attributed to the negatively charged PSS groups. An asymmetric visible irradiation on one side of the PSS-PPy membrane induces a built-in electric field across the membrane due to the intrinsic photoelectronic property of PPy, which drives the cationic transport against the concentration gradient, demonstrating an ion-pumping effect. This work is a prototype that uses a geometry-symmetric conducting polymer membrane as a light-powered artificial ion pump for active ion transport, which exhibits potential applications in nanofluidic energy conversion.

Prediction of high-risk areas of soil heavy metal pollution with multiple factors on a large scale in industrial agglomeration areas.

Heavy metals in soil are a great threat to ecosystems and human health. The rapid development of industrialization has created a serious risk of heavy metal pollution in soil. The study took the industrial-intensive Dahetan subbasin as the typical area. The factors and interactions that affected the distribution of soil heavy metals (Cd, Hg, As, Pb and Cr) in the typical area were explored based on the Geodetector model. The analysis results were extended to predict high-risk areas of heavy metal pollution in the soil in the Xiangjiang River basin. The results showed that Cd, As and Pb were significantly affected by local industrial and mining activities, and Hg and Cr were primarily affected by natural factors, such as pH and soil type. Compared to a single factor, the interaction between factors had a greater impact on the concentration of heavy metals. The high-risk areas of soil heavy metal pollution in the Xiangjiang River basin were primarily concentrated in the upper reaches and middle reaches.Significant overlapping of high-risk areas of multiple heavy metals occurred in the west, middle and south of the basin. The spatial visualization of the high-risk areas was realized, and the influence of several factors was integrated via layer superposition. This study proposes a new idea to predict the high-risk areas of soil pollution in large-scale areas to provide a reference for the regional prevention and control of soil pollution.

Plasmonic ternary hybrid photocatalyst based on polymeric g-C3N4 towards visible light hydrogen generation.

Surface plasmon resonance (SPR) effect of noble metal nanoparticles (NPs) for photocatalysis has a significant enhancement. In this system, a plasmonic ternary hybrid photocatalyst of Ag/AgBr/g-C3N4 was synthetized and used in water splitting to generation H2 under visible light irradiation. 18%Ag/AgBr/g-C3N4 showed the highest photoactivity, with the efficiency of hydrogen generation as high as 27-fold to that of pristine g-C3N4. Compared to simple mixture of Ag/AgBr and g-C3N4, hetero-composite Ag/AgBr/g-C3N4 showed a higher photoactivity, even though they contained same content of Ag/AgBr. We find that significant factors for enhancing properties were the synergistic effect between Ag/AgBr and g-C3N4, and the light absorption enhancing by SPR effect of Ag NPs. Ag/AgBr NPs firmly anchored on the surface of g-C3N4 and their high dispersion were also responsible for the improved activity and long-term recycling ability. The structure of Ag/AgBr/g-C3N4 hybrid materials and their enhancement to photocatalytic activity were discussed. Meanwhile, the possible reaction mechanism of this system was proposed.

An ionic diode based on a spontaneously formed polypyrrole-modified graphene oxide membrane.

Asymmetric membranes derived from the stacking of graphene oxide (GO) nanosheets have attracted great attention for the fabrication of ionic diodes. Herein, we described an ionic diode based on a polypyrrole-modified GO membrane with a vertical asymmetry, which was achieved by a spontaneous oxidation polymerization of pyrrole monomers on one side of the GO membrane in vapor phase. This asymmetric modification resulted in an asymmetric geometry due to the occupation of the interlayer space of one side of the GO membrane by polypyrrole. Our ionic diode demonstrated an obvious ionic rectification behavior over a wide voltage range. A calculation based on Poisson-Nernst-Planck equations was used to theoretically investigate the role of asymmetric modification of polypyrrole.