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The humidity sensors based on metal halide perovskite have achieved outstanding improvement. However, there are few reports of perovskite nanocrystals for humidity sensors. Herein, CsPdBr3 nanocrystals with high surface‐to‐volume ratio are synthesized by the in situ spin‐coating method. Subsequently, the humidity sensor based on CsPdBr3 nanocrystals is prepared and the response mechanism is demonstrated to originate from the formation of the Pd––O bond on the surface by performing density functional theory calculation. The humidity sensor shows a fast response/recovery time of 0.68/2.43 s in a relative humidity range from 88.9%RH to 4.7%RH; the fast response/recovery properties are used to monitor human respiratory and noncontact switch. Moreover, the hydromechanical characteristics of unsaturated soil are obtained by noncontact testing with the humidity sensor for the first time in geological engineering, and the strong correlation between relative humidity and hydromechanical characteristics is revealed by mathematical derivation, which lays the theoretical foundation for the noncontact real‐time sensing of hydromechanical characteristics of unsaturated soil. These findings not only open the door to the development of perovskite nanocrystals materials for humidity measurement, but also offer a new method for nondestructive and real‐time test of the mechanical properties of soil in geological engineering. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) gas is one of the highly toxic, lethal, and corrosive gases in the environment that can cause a series of inimical effects after human exposure. Therefore, developing gas-sensitive nanomaterials that could effectively detect the ultralow concentration of H2S is of utmost significance. In this study, a perovskite quantum dot (QD) structure is synthesized through a simple solution method in which CsPbBr3 QDs are surface capped with tributyltin oxide (TBTO). It was employed as a chemiresistor to H2S, exhibiting exceptional repeatability, superior selectivity, and an ultralow limit of detection of 250 ppb with a response sensitivity of 0.58 at room temperature, which is the highest value for H2S sensors based on metal-halide perovskite structure. The response/recovery time is 278/730 s at a 100 ppm concentration of H2S. Furthermore, we proposed the sensing mechanism of dispersion-sensing effect of the metallo-organic ligand by theory calculation to explain the excellent response performance. The chemical adsorption sensitivity of the related chemical groups is amended when the metallo-organic molecular is engrossed on the surface of CsPbBr3 QDs and becomes an isolated ligand. Thus, the H2S molecule is first absorbed by the isolated TBTO molecule, which prevents H2S from penetrating the perovskite CsPbBr3, forming a Pb–S bond, and damaging the sensing performance. Meanwhile, the H2S adsorption also affects the charge distribution of the internal CsPbBr3 QDs through a metallo-organic TBTO molecule, enhancing the sensitivity and response to H2S. Overall, the nanomaterial's structure and gas response mechanism could be extended to detecting other gases. [ABSTRACT FROM AUTHOR]

Background: The rabbit VX-2 tumor model is a commonly used transplanted tumor model and is widely used in surgical, radiological, and interventional studies. Most of the known tumor models for each site are single solid tumors. This study aimed to establish an accurate and stable intramuscular dual tumor model guided by computed tomography (CT)., Methods: In this study, we compared three different inoculation methods to select the most appropriate dual tumor model. Six New Zealand White rabbits were used as tumor-carrying rabbits for tumor harvesting. Thirty rabbits were divided into three groups as experimental rabbits. Group A applied the tumor cell suspension method, in which the suspension was injected into the designated location with a syringe under CT guidance. Groups B and C used tumor tissue strips obtained in vivo or under direct in vitro vision. The tumor tissue strips were implanted into the designated locations using a guide needle under CT guidance. The differences in tumorigenic rate, the size difference between bilateral tumors, and metastasis between the three methods were compared., Results: It was found that group A obtained a 100% tumor survival rate, but the size of the tumor was more variable, and needle tract implantation metastasis occurred in 5 cases. In group B, tumor tissue strips were taken in vivo for implantation, in which one case failed to survive. Tumor tissue strips in group C were obtained in vitro under direct vision. The tumor tissue strips obtained in vitro by puncture using a biopsy needle in group C had a 100% tumorigenicity rate and stable tumor size. No significant needle tract implantation metastases were found in either group B or C. The variance of tumor size obtained in group A was significantly higher than in groups B and C. The variance of tumor size in group C was the smallest. Group C had high tumorigenicity and a more stable size and morphology of the formed tumors., Conclusion: The results showed that the method of obtaining tumor tissue strips using in vitro direct vision puncture and implanting them into the muscle with CT guidance and guide needles can establish an accurate and stable dual tumor model. This dual tumor model can provide substantial support for relevant preclinical studies., Competing Interests: The authors declare there are no competing interests., (©2021 Meng et al.)

Background: The traditional treatment for osteoid osteoma is the nidus' surgical resection, which was difficult to eradicate with more invasive and complications because of osteosclerosis surrounding the nidus. This study aimed to analyze the efficacy and safety of percutaneous CT-guided cryoablation of osteoid osteoma at different sites (especially refractory sites such as the spine)., Methods: Fifteen patients with osteoid osteoma who underwent cryoablation at our institution were analyzed retrospectively on their imaging data and clinical visual analog scale (VAS) pain scores before and after the procedure. Fifty-three patients underwent surgical resection during the period were also included in this study as a control group. Treatment efficacy was assessed primarily by comparing the differences in VAS scores at different time points in each group of patients by paired-sample t-test. Differences in length of hospital stay and complications between the two groups were also compared., Results: The technical success rate was 100% in both the cryoablation and surgical resection group. Cryoablation had a significantly shorter hospitalization time than surgery ( p = 0.001). Clinically, the post-operative VAS scores were all significantly improved compared to the pre-operative period, and the clinical cure was achieved in both groups. Surgical operations had more complications than cryoablation, although there was no significant difference. In the group of cryoablation, only one patient had mild numbness of the left lower extremity, which relieved itself; two patients had mild post-operative pain. No patients in the cryoablation group experienced recurrence during the follow-up period. In the surgery group, three of the patients experienced massive bleeding (>500 ml), and two underwent transfusion therapy. Only one patient in the surgical resection group experienced a recurrence at 29 months postoperatively and underwent a second resection. All patients had local scars on the skin after surgical resection., Conclusion: Cryoablation is a minimally invasive, safe, and effective treatment strategy for osteoid osteoma, and is fully comparable to surgical resection., Competing Interests: The authors declare there are no competing interests., (©2021 Meng et al.)

Several aberrant microRNAs (miRNAs or miRs) have been implicated in esophageal cancer (EC), which is widely prevalent in China. However, their role in EC tumorigenesis has not yet been fully elucidated. In the present study, we determined that miR‑1 was downregulated in esophageal squamous cell carcinoma (ESCC) tissues compared with adjacent non-neoplastic tissues using RT-qPCR, and confirmed this using an ESCC cell line. Using a nude mouse xenograft model, we confirmed that the re-expression of miR‑1 significantly inhibited ESCC tumor growth. A tetrazolium assay and a trypan blue exclusion assay revealed that miR‑1 suppressed ESCC cell proliferation and increased apoptosis, whereas the silencing of miR‑1 promoted cell proliferation and decreased apoptosis, suggesting that miR‑1 is a novel tumor suppressor. To elucidate the molecular mechanisms of action of miR‑1 in ESCC, we investigated putative targets using bioinformatics tools. MET, cyclin D1 and cyclin-dependent kinase 4 (CDK4), which are involved in the hepatocyte growth factor (HGF)/MET signaling pathway, were found to be targets of miR‑1. miR‑1 expression inversely correlated with MET, cyclin D1 and CDK4 expression in ESCC cells. miR‑1 directly targeted MET, cyclin D1 and CDK4, suppressing ESCC cell growth. The newly identified miR‑1/MET/cyclin D1/CDK4 axis provides new insight into the molecular mechanisms of ESCC pathogenesis and indicates a novel strategy for the diagnosis and treatment of ESCC.