Prediction of false-positive PI-RADS 5 lesions on prostate multiparametric MRI: development and internal validation of a clinical-radiological characteristics based nomogram.

BACKGROUND: To develop a risk model including clinical and radiological characteristics to predict false-positive The Prostate Imaging Reporting and Data System (PI-RADS) 5 lesions. METHODS: Data of 612 biopsy-naïve patients who had undergone multiparametric magnetic resonance imaging (mpMRI) before prostate biopsy were collected. Clinical variables and radiological variables on mpMRI were adopted. Lesions were divided into the training and validation cohort randomly. Stepwise multivariate logistic regression analysis with backward elimination was performed to screen out variables with significant difference. A diagnostic nomogram was developed in the training cohort and further validated in the validation cohort. Calibration curve and receiver operating characteristic (ROC) analysis were also performed. RESULTS: 296 PI-RADS 5 lesions in 294 patients were randomly divided into the training and validation cohort (208 : 88). 132 and 56 lesions were confirmed to be clinically significant prostate cancer in the training and validation cohort respectively. The diagnostic nomogram was developed based on prostate specific antigen density, the maximum diameter of lesion, zonality of lesion, apparent diffusion coefficient minimum value and apparent diffusion coefficient minimum value ratio. The C-index of the model was 0.821 in the training cohort and 0.871 in the validation cohort. The calibration curve showed good agreement between the estimation and observation in the two cohorts. When the optimal cutoff values of ROC were 0.288 in the validation cohort, the sensitivity, specificity, PPV, and NPV were 90.6%, 67.9%, 61.7%, and 92.7% in the validation cohort, potentially avoiding 9.7% unnecessary prostate biopsies. CONCLUSIONS: We developed and validated a diagnostic nomogram by including 5 factors. False positive PI-RADS 5 lesions could be distinguished from clinically significant ones, thus avoiding unnecessary prostate biopsy.

Mechanism on redistribution synthesis of dichlorodimethylsilane by AlCl3/ZSM-5(3T)@γ-Al2O3 core-shell catalyst.

The redistribution method plays an important role in addressing the issue of organosilicon by-products in the direct synthesis of dichlorodimethylsilane, and the redistribution mechanism is still a topic of debate. The redistribution mechanism by the ZSM-5(3 T)@γ-Al2O3 core-shell catalyst and post-modified AlCl3/ZSM-5(3 T)@γ-Al2O3 catalyst was technically performed using the Density functional theory (DFT) at the level of B3LYP/6-311 + + G(3df,2pd). The results show that no. 1 active site of ZSM-5(3 T)@γ-Al2O3 core-shell structure has a significant effect on the activity of the catalyst. Indicating that the active center involved in the reaction is H provided by the Al-O-H bond, which is an obvious catalytic active center of Bronsted acid. Furthermore, the post-modified AlCl3/ZSM-5(3T)@γ-Al2O3 catalyst is in more favor of redistribution reaction comparing with the ZSM-5(3 T)@γ-Al2O3 core-shell catalyst. It ascribes to the robust Lewis site of aluminum chloride favorable modification. The redistribution synthesis mechanism of dichlorodimethylsilane on the ZSM-5(3 T)@γ-Al2O3 core-shell catalyst and post-modified AlCl3/ZSM-5(3 T)@γ-Al2O3 catalyst had been investigated by using the Density functional theory (DFT) method at the level of B3LYP/6-311 + + G(3df,2pd). The former active center was Bronsted acidic center, while the latter one was Lewis acidic center, ascribing to the Lewis site of aluminum chloride favorable modification. The catalytic activity of the post-synthesis AlCl3/ZSM-5(3 T)@γ-Al2O3 catalyst completely was consistent with experimental results.

[Relationship between physical activity and cognition function among people aged 55 and above in 4 provinces of China].

OBJECTIVE: To analyze the relationship between different intensity of physical activity(PA) duration and cognitive function. METHODS: The 2018 Community-based Cohort Study on Nervous System Diseases used multi-stage stratified cluster randomization sampling method to select study participants. A total of 5571 participants aged 55 years and above from four provinces in China with complete information on demographic characteristics and PA and cognitive function were included in the final analysis. Basic information and PA data were collected by questionnaire. The Montreal cognitive assessment(MoCA) score method was adopted to evaluate the cognitive function. Light physical activity(LPA) duration and moderate-to-vigorous physical activity(MVPA) duration were calculated. Multivariate Logistic regression and Multiple linear regressions were used to analyze the relationship between different intensity of PA duration and the risk of mild cognitive impairment(MCI) and MoCA total score. RESULTS: The median(P25, P75) of LPA and MVPA were 7. 0(0. 0, 16. 3) and 7. 3(0. 0, 14. 0) hours per week in the non-MCI group among 5571 participants aged 55 years and above in four provinces of China in 2018. In the MCI group, the median duration were 9. 3(0. 0, 17. 5) and 7. 0(0. 0, 11. 7) hours per week. The Logistic analysis showed that the OR of MCI was 0. 63(95%CI 0. 49-0. 82, P<0. 05) for the elderly with 3. 6-7. 0 hours of MVPA per week, compared to the elderly without MVPA. The OR of MCI was 1. 26(95%CI 0. 94-1. 67, P>0. 05) for the elderly with 3. 6-7. 0 hours of LPA per week compared to the elderly without LPA. Multiple linear regression analysis showed that compared to the elderly without MVPA, the total MoCA score increased with LPA duration increased as the duration was less than 10. 5 hours per week. The MoCA score decreased with LPA duration increased as duration was between 10. 5 and 21. 0 hours per week. CONCLUSION: MVPA duration increment was associated with decreased prevalence of MCI and increased cognitive function in the elderly in four provinces of China. LPA duration should be maintained at an appropriate level in order to reduce the incidence of MCI and increased cognitive function in the elderly.

Chemical pre-reduction and electro-reduction guided preparation of a porous graphene bionanocomposite for indole-3-acetic acid detection.

A porous graphene (PG) bionanocomposite of PG, gold nanoparticles (AuNPs) and anti-indole-3-acetic acid (anti-IAA) antibody for sensitive and label-free amperometric immunoassay of IAA was reported. A PG film was produced by a pre-reduction/electrochemical reduction process on a glassy carbon electrode (GCE) and then a homogeneous AuNPs layer electrodeposition on the PG film. The anti-IAA antibody was immobilized onto the AuNPs through electrostatic adsorption and covalent conjugation. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), elecro-chemical impedance spectroscopy (EIS), ultraviolet visible spectroscopy (UV-vis) and differential pulse voltammetry (DPV) were used to characterize the PG film and the stepwise modification of the immunosensor. The electrochemical immunosensor exhibited a wide linear range from 2 × 10-11 to 2 × 10-8 g mL-1 with a detection limit of 0.016 ng mL-1 (S/N = 3) and showed significant linearity R2 = 0.9970. In addition, the proposed immunosensor showed acceptable selectivity and has been applied to the determination of IAA in the extract samples of several plant seeds with acceptable relative derivation (%) ranging from -5.25% to 4.24% between the immunosensor and high performance liquid chromatography. The proposed chemical pre-reduction and electro-reduction guided protocol can be extended to the preparation of many other functionalized PG nanocomposite films for wide applications.

Dispersing gold nanoparticles on thiolated polyaniline-multiwalled carbon nanotubes for development of an indole-3-acetic acid amperometric immunosensor.

An amperometric immunosensor based on new thiolated bionanocomposite with a high dispersion of gold nanoparticles (AuNPs) for the sensitive detection of indole-3-acetic acid (IAA) is being reported herein. Briefly, a thiolated nanocomposite was prepared via the microwave-assisted thiol-ene reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) with oxidized polyaniline (PANI), which was synthesized in the presence of multiwalled carbon nanotubes (MWCNTs), yielding thiolated polyaniline (TPANI)-MWCNTs. Further, AuNPs were deposited on the TPANI-MWCNTs by microwave-assisted method to obtain a AuNPs/TPANI-MWCNTs nanocomposite. Finally, the thiolated bionanocomposite film was constructed via the specific chemical reaction between boronic acid functionalized AuNPs and the vicinal diol functionalized AuNP labeled immunoglobulin G (IgG-AuNPs). The change in the reduction peak current of Fe(CN)6 3- was used to monitor the immunoreaction between IAA and antibody. The TPANI-MWCNT nanocomposites uniformly disperse AuNPs, IgG-AuNPs and anti-IAA-AuNPs, leading to the amplification of the signal of the immunosensor. Fourier transform infrared spectra (FTIR), cyclic voltammetry (CV), transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV-vis) and differential pulse voltammetry (DPV) were used to characterize the nanocomposite film and the stepwise modification of the immunosensor. The prepared thiolated bionanocomposite material has good biocompatibility, a highly uniform dispersion of the AuNPs with a narrow size distribution as verified by TEM, and high load/activity of the immobilized antibody proved via DPV. The fabricated IAA amperometric immunosensor not only exhibits a good linear arrange from 1.0 pg mL-1 to 10 ng mL-1 with the limit of detection of 0.97 pg mL-1 (S/N = 3), but also possesses good selectivity, reproducibility and stability for the detection of IAA.

Enhanced electrocatalytic performance of platinum nanoparticles on thiolated polyaniline-multiwalled carbon nanotubes for methanol oxidation.

Pt nanoparticles (PtNPs) well-dispersed on thiolated polyaniline (TPANI)-multiwalled carbon nanotubes (MWCNTs) were prepared for enhanced electrocatalytic oxidation of methanol in acidic media. Briefly, the preparation of nanocomposites was carried out via microwave-assisted thiol-ene reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) with oxidized PANI, which was synthesized in the presence of MWCNTs, yielding TPANI-MWCNTs; then, PtNPs were deposited on TPANI-MWCNTs by a microwave-assisted method to obtain PtNPs/TPANI-MWCNT nanohybrids. Fourier transform infrared spectroscopy, cyclic voltammetry (CV), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and inductively coupled plasma-atom emission spectroscopy were used to study relevant nanohybrid properties. TEM showed that PtNPs were well dispersed on TPANI-MWCNTs. TGA showed that PtNPs/TPANI-MWCNTs exhibited better thermal stability than PtNPs/TPANI-MWCNTs and PtNPs/MWCNTs. CV studies showed that PtNPs/TPANI-MWCNT-modified glassy carbon electrode (GCE) exhibited a larger electrochemically active surface area and higher electrocatalytic performance toward methanol electro-oxidation compared with those of PtNPs/PANI-MWCNTs/GCE and PtNPs/MWCNTs/GCE. Also, the PtNPs/TPANI-MWCNTs/GCE electrode possessed high stability and maintained 86% of its initial catalytic activity after 1000-cycle CV in 1.0 M CH3OH + 0.5 M H2SO4.