Sarcoidosis with Severe Bone Involvement: A Case Report and Literature Review.

Sarcoidosis is a systemic granulomatous disease of the lungs that commonly involves intrathoracic lymph nodes. Here, we report the case of a 68-year-old woman who complained of shortness of breath and had suffered from the enlargement of intrathoracic lymph nodes for 12 years, swelling of the right middle finger for 7 years, and nasal obstruction for 2 years. The damage to the phalange was aggravated continuously and a malignant lesion could not be excluded, thus leading to amputation of the right middle finger. Pathological data indicated chronic inflammatory granulomatous disease and anti-acid staining was negative. Examination of the paranasal sinuses indicated destruction of the sinonasal bone and the swollen mucosa. Combined with the elevated ratio of CD4+/CD8+ T cells in bronchoalveolar lavage fluid and other results, the patient was finally diagnosed with sarcoidosis and received corticosteroid therapy. The shortness of breath and abnormality of the nose were significantly improved after treatment. Our case demonstrated the process of differential diagnosis for systemic granulomatous diseases, indicating the necessity of corticosteroid therapy for systematic sarcoidosis.

A controllable surface etching strategy for MOF-derived porous ZnCo2O4@ZnO/Co3O4 oxides and their sensing properties.

Here, we report a surface etching strategy for the controllable synthesis of metal-organic framework (MOF)-derived ZnCo2O4@ZnO/Co3O4 oxides. Different from previous studies, ZnCo-glycolate (ZnCo-gly) spheres acted as sacrificial templates to provide Zn2+ and Co2+ ions, which coordinated with 2-MeIm to form Zeolitic Imidazolate Frameworks (ZIFs) on the surface of ZnCo-gly. A series of characterizations were employed to clarify the evolution of the surface etching strategy. Interestingly, the ZIF thickness of the ZnCo-gly surface could be controlled by adjusting the reaction time. After calcination, p-n heterojunctions were formed between the MOF-derived ZnO and Co3O4, which made it show excellent selectivity to methanal gas.

Kynurenic acid promotes osteogenesis via the Wnt/ß-catenin signaling.

The role of kynurenic acid (KynA) in neurological and mental diseases has been widely studied. Emerging studies disclosed that KynA has a protective effect on tissues including heart, kidney, and retina. However, the role of KynA in osteoporosis has not been reported so far. To elucidate the role of KynA in age-related osteoporosis, both control and osteoporosis mice were administrated KynA for three consecutive months, and micro-computed tomography (µCT) analysis was then performed. In addition, primary bone marrow mesenchymal stem cells (BMSCs) were isolated for osteogenic differentiation induction and treated with KynA in vitro. Our data suggested that KynA administration rescued age-related bone loss in vivo, and KynA treatment promotes BMSC osteogenic differentiation in vitro. Moreover, KynA activated the Wnt/ß-catenin signaling during BMSC osteogenic differentiation. Wnt inhibitor MSAB inhibited KynA-induced osteogenic differentiation. Further data demonstrated that KynA exerted its effect on BMSC osteogenic differentiation and Wnt/ß-catenin signaling activation via G protein-coupled receptor 35 (GPR35). In conclusion, the protective effect of KynA on age-related osteoporosis was disclosed. Additionally, the promoting effect of KynA on osteoblastic differentiation via Wnt/ß-catenin signaling was verified and the effect dependent on GPR35. These data suggest that KynA administration potentially contributes to the treatment of age-related osteoporosis.

Ultrasonic Elastography-guided Pleural Biopsy for the Diagnosis of Pleural Effusion: A Multicenter Prospective Study of Diagnostic Test Performance.

Rationale: The diagnostic yield of traditional ultrasound-guided pleural biopsy remains unsatisfactory, particularly when the pleural thickness is ⩽5 mm and/or no pleural nodules are detected. Pleural ultrasound elastography (UE) has a better diagnostic yield than traditional ultrasound for malignant pleural effusion (MPE). However, studies on UE-guided pleural biopsies are lacking. Objectives: To evaluate the feasibility and safety of UE-guided pleural biopsy. Methods: In this multicenter prospective single-arm trial, patients with pleural effusion whose pleural thickness was ⩽5 mm with no pleural nodules were enrolled between July 2019 and August 2021. The diagnostic yield of UE-guided pleural biopsy for pleural effusion and its sensitivity for detecting MPE were evaluated. Results: Ninety-eight patients (mean age, 62.4 ± 13.2 yr; 65 men) were prospectively enrolled. The diagnostic yield of UE-guided pleural biopsy for making any diagnosis was 92.9% (91/98), and its sensitivity for MPE was 88.7% (55/62). In addition, its sensitivity for pleural tuberculosis was 69.6% (16/23). The rate of postoperative chest pain was acceptable, and there was no pneumothorax. Conclusions: UE-guided pleural biopsy is a novel technique for diagnosing MPE with good diagnostic yield and sensitivity. Clinical trial registered with https://www.chictr.org.cn (ChiCTR2000033572).

A detection panel of novel methylated DNA markers for malignant pleural effusion.

Background: Cytology remains the gold standard for the detection of malignant cells in pleural effusion. However, its sensitivity is limited. The aim of this study was to establish a novel panel of cancer-specific methylated genes for the differential diagnosis of malignant pleural effusion (MPE). Methods: A cohort of 100 cancer patients (68 lung cancer, 32 other malignant tumors) and 48 patients with benign disease presenting with pleural effusion was prospectively enrolled. Pleural effusion was evaluated by means of cytopathological investigation and DNA methylation of SHOX2, RASSF1A, SEPTIN9 and HOXA9 in the cellular fraction. DNA methylation in bisulfite-converted DNA was determined using quantitative methylation-specific real-time PCR (MS-PCR). Cytopathological and DNA methylation results were evaluated with regard to the final clinical diagnosis. Results: The LungMe® SHOX2 and RASSF1A Assay (Tellgen Corporation, China) has been reported to be highly sensitive and specific for lung cancer using bronchial aspirates. As expected, LungMe® detected metastases of lung cancer (sensitivity: 76.5%) as well as metastases of other malignant tumors (sensitivity: 68.8%). OncoMe, a novel combination of SHOX2, RASSF1A, SEPTIN9 and HOXA9 methylation, led to an additional 11% increase in the detection rate of MPE, resulting in a sensitivity of 85% and a specificity of 96%. Overall, OncoMe showed a higher positive detection rate in SCLC (100%), LUAC (87%), OC (100%), BC (92.9%), GC (80.0%), and MESO (80%) than in LUSC (50%). Cytopathological analyses only detected 23 positive samples, which were all positively measured by both LungMe® and OncoMe. Conclusion: OncoMe has potential for use as a biomarker for the detection of MPE, even not limited to lung cancer.

The constricting effect of reduced coronary artery compliance on the left ventricle is an important cause of reduced diastolic function in patients with coronary heart disease.

BACKGROUND: Previous studies of left ventricular diastolic function (LVDF) have focused on the decrease in active and passive diastolic function due to ischemic factors but have not investigated if the decrease in compliance of the coronary arteries that bypass the surface of the heart and travel between the myocardium could cause a constricting effect on the ventricular wall like that caused by myocardial fibrosis. METHODS AND RESULTS: 581 patients diagnosed with coronary heart disease (CHD) were divided into A group (patients are the control group), B group (patients with less than 50% coronary artery stenosis), C group (patients with coronary artery stenosis between 50 and 75%), D group (patients with coronary artery stenosis greater than 75%) according to the degree of coronary stenosis. The diastolic function of the ventricle is reflected by applying the relaxation time constant T value, which refers to the time between peak dp/dt and end-diastolic pressure in the left ventricle. It was concluded that there was a statistical difference in Gensini scores between patients in groups B, C and D (P < 0.001). And multiple linear regression analysis showed that T was correlated with Gensini score and C-dp/dtmax (R = 0.711, P < 0.001). Grouping according to the site of stent implantation and the number of stents implanted, it was found out that the changes in T values before and after left anterior descending artery (LAD) stent implantation were greater than left circumflex artery (LCX) and right coronary artery (RCA) (P < 0.001). And multiple linear regression revealed a correlation between T values and stent length, ventricular stiffness, and C-dp/dtmax (P = 0.001). CONCLUSIONS: The decrease in compliance of the coronary arteries bypassing the surface of the heart and travelling between the myocardium would cause a constricting effect on the ventricular wall like that caused by myocardial fibrosis.

G-protein-coupled receptor 124 promotes osteogenic differentiation of BMSCs through the Wnt/ß-catenin pathway.

Osteoporosis occurs frequently in women after menopause and old age, and it is very easy to cause osteoporotic fractures, resulting in disability and death. In osteoporosis patients, the potential of bone marrow mesenchymal stem cells (BMSCs) to differentiate into osteoblasts gradually is inhibited, leading to decreased new bone formation. In the current study, the potential effect of G-protein-coupled receptor 124 (GPR124) on the osteoblastic differentiation of BMSCs was determined. BMSCs were isolated and cultured in osteogenic media to induced osteogenic differentiation. Then, osteogenic differentiation was evaluated by Alizarin Red staining and ALP activity. The expression of osteogenic differentiation biomarkers, and Wnt/ß-catenin signaling were determined by qRT-PCR and Western blotting. The results indicated that the expression of GPR124 was significantly increased during osteogenic differentiation of BMSCs. Moreover, GPR124 knockdown significantly inhibited osteoblastic differentiation and GPR124 overexpression promoted osteoblastic differentiation of BMSCs. GPR124 knockdown suppressed the activation of Wnt/ß-catenin signaling pathway. What's more, the increased osteogenic differentiation induced by GPR124 overexpression was abolished by the inhibitor of Wnt/ß-catenin pathway and Wnt7a knockdown. Taken together, GPR124 promotes osteogenic differentiation of BMSCs through the Wnt/ß-catenin pathway and may serve as a potential target for enhancing osteogenesis of osteoporosis patients.

MicroRNA-146a-3p/HDAC1/KLF5/IKBα signal axis modulates plaque formation of atherosclerosis mice.

BACKGROUND: Atherosclerosis (AS) is a multifocal, smoldering immune inflammatory disease of medium and large arteries driven by lipids. The aim of this study is to discuss the mechanism of microRNA-146a-3p (miR-146a-3p)/histone deacetylase 1 (HDAC1)/Krüppel-like factor 5 (KLF5)/inhibitors of kappa B α (IKBα) signal axis in plaque formation of AS mice. METHODS: ApoE-/- mice were fed with high-fat feed for 12 weeks to establish AS mice model. The expression of miR-146a-3p, KLF5, HDAC1 and IKBα in aortic wall tissues of AS mice was tested. The targeting relationship between miR-146a-3p and HDAC1 was verified. AS mice were injected with miR-146a-3p antagomir or HDAC1 overexpression to verify the impacts of miR-146a-3p and HDAC1 on blood lipids and inflammatory factors in serum, aortic wall apoptotic cells, antioxidant stress capacity and the plaque area in AS mice. VECs proliferation and apoptosis were also measured in vitro. RESULTS: miR-146a-3p and KLF5 were increased while HDAC1 and IKBα were reduced in aortic wall tissues of AS mice. miR-146a-3p directly targeted to HDAC1. Depletion of miR-146a-3p or restoration of HDAC1 was correlated to lower plasma lipid level, reduced inflammatory factors in serum, attenuated aortic wall apoptosis, increased antioxidant stress capacity and improved the stability of pathological plaque of AS mice. miR-146a-3p down-regulation or HDAC1 up-regulation promoted VECs proliferation and inhibited apoptosis. CONCLUSION: Functional studies show that depleted miR-146a-3p advances HDAC1 and IKBα expression as well as inhibits KLF5 expression to facilitate the stability of pathological plaques in AS mice.

Case Report: A Patient With COVID-19 Who Benefited From Hemoadsorption.

In December 2019, the 2019 novel coronavirus disease (COVID-19), which has been identified to be caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in China and spread across the world. Higher plasma levels of cytokines, including interleukin (IL)-6, IL-2, IL-7, IL-10, and tumor necrosis factor-α, were found in patients with COVID-19, which implies the occurrence of a cytokine storm and its association with disease severity. Extracorporeal blood purification has been proven to effectively remove the released inflammatory cytokines. In this study, we report on a patient with COVID-19 who benefited from hemoadsorption.

Malignant Transformation of a Borderline Ovarian Tumor With Pulmonary and Pleural Metastases After Years of Latency: A Case Report and Literature Review.

Borderline ovarian tumor (BOT) refers to a distinct tumor of the ovary of epithelial origin and typically has a favorable prognosis. However, these tumors are not exempt from risks of recurrence and malignant transformation, which can arise from the remaining ovarian tissue, peritoneal implants, or distant localization. Here, we report a case of a mucinous BOT with multiple pulmonary cystic nodules without evidence of pulmonary metastasis even after two fine needle biopsies. Staging surgery was performed, and no evidence of peritoneal implants or invasion to adjacent organs found. At the end of the 7-year monitored follow-up after surgery, the pulmonary lesions were found to be increased in size. The transbronchial lung biopsy and pleural biopsy confirmed transformation into malignant mucinous adenocarcinoma with pleural metastasis. In the current case, we observed potential pulmonary metastasis of the BOT with malignant transformation and a latency as long as 7 years, which reminds us that multiple pulmonary cystic changes in patients with BOTs should be screened carefully to evaluate the pulmonary involvement of BOTs and potentially false-negative results after fine needle biopsy. Thus, a thorough check-up for complete staging of the disease and a close long-term follow-up to monitor potential recurrence and malignant transformation are advised.

Preaddition of Cations to Electrolytes for Aqueous 2.2 V High Voltage Hybrid Supercapacitor with Superlong Cycling Life and Its Energy Storage Mechanism.

Electrolyte solutions and electrode active materials, as core components of energy storage devices, have a great impact on the overall performance. Currently, supercapacitors suffer from the drawbacks of low energy density and poor cyclic stability in typical alkaline aqueous electrolytes. Herein, the ultrathin Co3O4 anode material is synthesized by a facile electrodeposition, followed by postheat treatment process. It is found that the decomposition of active materials induces reduction of energy density and specific capacitance during electrochemical testing. Therefore, a new strategy of preadding Co2+ cations to achieve the dissolution equilibrium of cobalt in active materials is proposed, which can improve the cyclic lifetime of electrode materials and broaden the operation window of electrochemical devices. Co2+ and Li+ embedded in carbon electrode during charging can enhance H+ desorption energy barrier, further hampering the critical step of bulk water electrolysis. More importantly, the highly reversible chemical conversion mechanism between Co3O4 and protons is demonstrated to be the fact that a large amount of quantum dots and second-order flaky CoO layers were in situ formed in the electrochemical reaction process, which is first discovered and reported in neutral solutions. The as-assembled device achieves a high operation voltage (2.2 V), excellent cycling stability (capacitance retention of 168% after 10 000 cycles) and ultrahigh energy density (99 W h kg-1 at a power density of 1100 W kg-1). The as-prepared electrolytes and highly active electrode materials will open up new opportunities for aqueous supercapacitors with high safety, high voltage, high energy density, and long-lifespan.

Facile metal-organic frameworks-templated fabrication of hollow indium oxide microstructures for chlorine detection at low temperature.

Metal oxides with the hollow microstructure by the facile synthetic strategy are hopeful in applications for photocatalysis, supercapacitor, and gas sensor owing to their large surface areas, porosity ratio and rich active sites. In this work, indium oxide porous hollow rods (In2O3 PHRs) are successfully prepared using metal-organic frameworks (MOFs) as the template. The morphology of In2O3 PHRs is hexagonal hollow micro-rods with a porous structure. The investigation on the gas-sensing performance reveals that the In2O3 PHRs sensor displays outstanding sensitivity and selectivity toward 10 ppm chlorine gas (Cl2) at low operational temperature (160 °C). Furthermore, the In2O3 PHRs sensor displays a low detection limit (3.2 ppb) and short response and recovery time (38/13 s). The unique morphology and abundant oxygen vacancies are conduced to the excellent gas-sensing activities, which is benefited from the utilization and decomposition of In-MOFs precursor. In addition, the gas sensing mechanism of reducing gases and oxidizing gases is deduced in detail for the In2O3 PHRs sensor.

Graphitic carbon nitride with thermally-induced nitrogen defects: an efficient process to enhance photocatalytic H2 production performance.

Graphitic carbon nitride (g-C3N4, CN) with nitrogen vacancies was synthesized by a controlled thermal etching method in a semi-closed air-conditioning system. The defect-modified g-C3N4 shows an excellent photocatalytic performance demonstrated by water splitting under visible light irradiation. With proper heat-treatment durations such as 2 h (CN2) and 4 h (CN4) at 550 °C, the hydrogen production rates significantly increase to 100 µmol h-1 and 72 µmol h-1, which are 11 times and 8 times the rate of the pristine CN (8.8 µmol h-1) respectively. The excellent hydrogen production performance of nitrogen defect modified CN2 is due to the synergy effect of the decreased band gap, enlarged specific surface area and increased separation/migration efficiency of photoinduced charge carriers. This simple defect engineering method provides a good paradigm to improve the photocatalytic performance by tailoring the electronic and physical structures of g-C3N4.

A Codoped Polymeric Photocatalyst with Prolonged Carrier Lifetime and Extended Spectral Response up to 600 nm for Enhanced Hydrogen Evolution.

The intrinsic properties of photocatalysts, such as electron state and energy band structure, contribute significantly to their catalytic performance. However, it is difficult to alter these properties of semiconductors by conventional modifications. To adjust the intrinsic properties while preserving long-term conjugation of the polymeric photocatalysts, a post-thermal treatment is proposed to codope P and Na into polymeric carbon nitride in this work. After codoping, the absorption of visible irradiation is strongly extended up to 639 nm. Additionally, the lifetime of charge carriers is almost tripled from 1.09 to 2.93 ns. The photocatalytic hydrogen evolution performance under visible light is improved to 2032 µmol·h-1 g-1 in the optimized sample, corresponding to apparent quantum efficiencies of 6.79% and 0.09% at 420 and 600 nm, respectively. The enhanced catalytic activity is ascribed to the synergistic effects of prolonged lifetime and increased charge density that resulted from lattice distortion and extended visible utilization due to the formation of subgap state. Our work provides new pathways for the modification of polymeric catalysts toward high-performance and full-spectrum photocatalysis.

Altered pulmonary capillary permeability in immunosuppressed guinea pigs infected with Legionella pneumophila serogroup 1.

In immunosuppressed hosts, Legionella pneumophila (Lp) infection usually develops into severe pneumonia, which is pathologically characterized by increased vascular permeability and pulmonary edema. At present, mechanisms associated with changes in pulmonary capillary permeability (PCP) and the pathogenesis of pulmonary edema in immunosuppressed hosts with Lp infection are unclear. Therefore, in the present study an animal model of normal and immunosuppressed guinea pigs infected with Lp was established. An isolated perfused lung system was used to investigate the extent of changes in PCP. Pathological and immunofluorescence examinations were performed to explore the mechanism underlying these changes. The results indicated that PCP increased with the highest magnitude in immunosuppressed guinea pigs infected with Lp, with repeated ANOVA indicating synergism between infection and immunosuppression (P=0.0444). Hematoxylin and eosin staining and electron microscopy revealed more severe morphological damages in the lung tissues and pulmonary capillaries of the immunosuppressed animals infected with Lp compared with normal animals infected with Lp. Immunofluorescence analysis showed that immunosuppression reduced the expression of the vascular endothelial cell junction protein VE-cadherin (P=0.027). Following Lp infection, VE-cadherin expression was significantly lower in the immunosuppressed guinea pigs compared with their immunocompetent counterparts (P=0.001). These results suggest that immunosuppression combined with Lp infection induces more significant damage to pulmonary capillaries compared with Lp infection alone, resulting in a significantly increased PCP.

DPP-4 inhibitor anagliptin protects against hypoxia-induced cytotoxicity in cardiac H9C2 cells.

Cardiovascular complications are the leading cause of mortality and morbidity in type 2 diabetes patients. Diabetes greatly increases the risk of heart disease; therefore, the management of diabetes often involves the prevention of heart disease. DPP-4 inhibitors have been proven to be the effective therapeutic agents of glycaemic control. Recent studies have shown that certain types of DPP-4 inhibitors could also have cardiovascular benefits. In this study, we examined the protective role of the newly developed DPP-4 inhibitor anagliptin in cultured cardiac myocytic cell line H9C2 cells. Our data show that exposure of H9C2 cells to hypoxic conditions induced higher expression of DPP-4, indicating that DPP-4 is a hypoxia-inducible factor. The inhibition of DPP-4 by anagliptin ameliorates hypoxia-induced cytotoxicity and induction of the pro-inflammatory cytokines IL-6 and MCP-1. Anagliptin also suppresses hypoxia-induced oxidative stress as revealed by the detected levels of cellular ROS and reduced GSH. Moreover, anagliptin protects myocytes from hypoxia-associated reduced mitochondrial membrane potential. Mechanistically, we show that anagliptin promotes hypoxia-induced NFR2/HO1 induction but suppresses HMGB1 and MyD88 generation. Collectively, our data indicate that anagliptin-mediated DPP-4 inhibition is a protective mechanism in cardiomyocytes and imply that the DDP-4 inhibitor anagliptin plays dual roles by lowering glucose and protecting cardiomyocytes.

Endoscopic submucosal dissection of tracheal deep benign fibrous histiocytoma using hybrid knife.

Deep benign fibrous histiocytoma (FH) is an uncommon and poorly recognized tumor that arises in subcutaneous or deep soft tissue. Deep benign FH of the trachea is even more rare. Deep benign FH recurs in approximately 20% of cases, so surgical resection is the recommended treatment for FH. However, some patients are afraid of the trauma and potential complications from the resection of tracheal tumors, so they do not accept surgical resection. With the development of interventional pulmonology, bronchoscopic intervention plays a key role in the treatment of benign tracheal tumors. Novel tools have emerged in interventional pulmonology and optimized the traditional techniques. Here, we report a case of deep benign FH of the trachea with broad base relapse after electrocautery with snare, argon plasma coagulation (APC) and radiotherapy. It was treated successfully by endobronchial resection with a hybrid knife (HK) and APC. The HK is a hybrid device that combines an electrocautery knife with a water jet in one instrument. Submucosal injection and circumferential cutting and dissection of lesions as well as coagulation of bleeding can be performed only with the HK. During the 6 months follow-up, the deep benign FH of the trachea did not relapse. In the case reported herein, the HK enabled submucosal injection and circumferential cutting and dissection of lesions as well as access to submucosal lesions to gain further adequate APC treatment, thereby allowing a better clinical response than that achieved by traditional electrocautery with snare and APC. In conclusion, the HK with a water jet is a feasible and effective endoscopic method for management for benign or low-grade malignant neoplasms of the trachea, especially those with a wide base and submucosal involvement.

Sonic hedgehog signaling regulates hypoxia/reoxygenation-induced H9C2 myocardial cell apoptosis.

The sonic hedgehog (Shh) signaling pathway has been reported to protect cells against hypoxia/reoxygenation (H/R) injury; however, the role of Shh and relevant molecular mechanisms remain unclear. In the present study, the rat cardiomyoblast cell line H9C2 was subjected to hypoxia and serum-starvation for 4 h. Cells were subsequently reoxygenated using 95% O2 and 5% CO2. Reverse transcription-quantitative polymerase chain reaction was performed to quantify the expression of Shh mRNA, while cell apoptosis was assessed using flow cytometry. Caspase-3 activity and p53 expression were measured by western blotting and an MTT assay was subsequently used to assess cell viability. In addition, reactive oxygen species levels were measured using dichlorofluorescein and H/R-induced changes in the activation of superoxide dismutase, catalase, phosphorylated-endothelial nitric oxide synthase, phosphorylated-protein kinase B (Akt) and mammalian target of rapamycin activation were assessed using western blotting. H/R treatment decreased the cell viability of H9C2 cells, but activated endogenous Shh signaling. The activation of Shh signaling protected H9C2 myocardial cells from H/R-induced apoptosis and restored cell viability. In the present study, Shh signaling was demonstrated to serve a protective role against H/R by activating the phosphoinositol 3-kinase (PI3K)/Akt pathway and promoting the expression of anti-oxidant enzymes to ameliorate oxidative stress. In summary, Shh signaling attenuated H/R-induced apoptosis through via the PI3K/Akt pathway.

Ag modified bismuth ferrite nanospheres as a chlorine gas sensor.

Pure phase bismuth ferrite (BiFeO3, BFO) nanospheres were synthesized via a sol-gel method, and Ag was loaded on the surface of BFO by photodeposition. The effects of the Ag-modification on the morphologies and microstructural characteristics were investigated using transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) analyses. Only BFO peaks but no Ag peaks were observed for all samples in the XRD patterns, which is related to the small size and low loading of Ag. The gas-sensing tests show that the response of 4 mg AgNO3 modified BiFeO3 (ABFO4) was 72.62 to 10 ppm Cl2 at 240 °C, which was 2.5 times higher than that of the pristine BFO. Such outstanding gas sensing performances are attributed to the fact that the presence of Ag not only increases the density of holes and the amount of gas adsorption sites but also has a catalytic effect.

Pt-decorated zinc oxide nanorod arrays with graphitic carbon nitride nanosheets for highly efficient dual-functional gas sensing.

In this work, well-aligned ZnO nanorods were grown on the substrate of exfoliated g-C3N4 nanosheets via a microwave-assisted hydrothermal synthesis, and then Pt/ZnO/g-C3N4 nanostructures were obtained after the deposition of Pt nanoparticles. The growth of vertically ordered ZnO nanorods was occurred on g-C3N4 nanosheets through the bonding interaction between Zn and N atoms, which was confirmed by XPS, FT-IR data and molecular orbital theory. The Pt/ZnO/g-C3N4 nanostructures sensor exhibited the remarkable sensitivity, selectivity, and fast response/recovery time for air pollutants of ethanol and NO2. The application of Pt/ZnO/g-C3N4 nanostructures could be used as a dual-functional gas sensor through the controlled working temperature. Besides, the Pt/ZnO/g-C3N4 nanostructures sensor could be applied to the repeating detection of ethanol and NO2 in the natural environment. The synergistic effect and improved the separation of electron-hole pairs in Pt/ZnO/g-C3N4 nanostructures had been verified for the gas sensing mechanism. Additionally, Pt/ZnO/g-C3N4 nanostructures revealed the excellent charge carriers transport properties in electrochemical impedance spectroscopy (EIS), such as the longer electron lifetime (τn), higher electron diffusion coefficient (Dn) and bigger effective diffusion length (Ln), which also played an important role for Pt/ZnO/g-C3N4 nanostructures with striking gas sensing activities.