Dialkyl carbonates are important organic compounds and chemical intermediates with the label of "green chemicals" due to their moderate toxicity, biodegradability for human health and environment. ...Indeed, owing to their unique physicochemical properties and versatility as reagents, a variety of phosgene-free processes derived from CO or CO
2
have been explored for the synthesis of dialkyl carbonates. In this critical review, we highlight the recent achievements (since 1997) in the synthesis of dialkyl carbonates based on CO and CO
2
utilization, particularly focusing on the catalyst design and fabrication, structure-function relationship, catalytic mechanisms and process intensification. We also provide an overview regarding the applications of dialkyl carbonates as fuel additives, solvents and reaction intermediates (
i.e.
alkylating and carbonylating agents). Additionally, this review puts forward the substantial challenges and opportunities for future research associated with dialkyl carbonates.
This review describes the recent advances in the synthesis and applications of dialkyl carbonates, particularly focusing on the catalyst rational design, catalytic mechanism, and process intensification in the CO and CO
2
routes.
Carbon dioxide (CO2) is a major greenhouse gas and makes a significant contribution to global warming and climate change. Thus CO2 capture and storage (CCS) have attracted worldwide interest from ...both fundamental and practical research communities. Alkali-metal-based oxides such as alkali-metal oxides, binary oxides, and hydrotalcite-like compounds are promising adsorbents for CO2 capture because of their relatively high adsorption capacity, low cost, and wide availability. They can also be applied to the adsorption-enhanced reactions involving CO2. The microstructures (e.g., surface area, porosity, particle size, and dispersion) of these oxides determine the CO2 adsorption capacity and multicycle stability. This perspective critically assesses and gives an overview of recent developments in the synthesized method, adsorption mechanism, operational conditions, stability, and regenerability of a variety of oxides. Both pros and cons of these oxides are also discussed. Insights are provided into several effective procedures regarding microstructural control of alkali-metal-based oxides, including preparation optimization, modification, stream hydration, etc.
Currently, limited data on tyrosine kinase inhibitors as neoadjuvant therapy exist. This prospective study aimed to investigate the efficacy and safety of preoperative gefitinib in patients with ...stage II-IIIA operable non–small cell lung cancer (NSCLC).
This was a single-arm, phase II trial performed in the Shanghai Cancer Center. Between August 2013 and October 2015, patients with operable stage II-IIIA NSCLC with epidermal growth factor receptor (EGFR) exon 19 deletion or exon 21 L858R mutation were enrolled. Patients were treated with preoperative gefitinib (250 mg once daily for 42 days), followed by surgical resection. The primary endpoint was objective response rate (ORR); secondary endpoints were the rate of major pathologic response (MPR), disease-free survival (DFS), overall survival, and adverse events (AEs). ORR was defined as the proportion of patients achieving complete response or partial response radiologically. MPR was defined as no more than 10% viable tumor.
Of the 35 eligible patients, 33 were considered as intention-to-treat population. ORR, the primary endpoint, was 54.5% (95% confidence interval CI, 37.7-70.7), and the rate of MPR was 24.2% (95% CI, 11.9-40.4). Median DFS was 33.5 months (95% CI, 19.7-47.3); median overall survival was not reached. Skin toxicity (24/35,68.6%) and gastrointestinal symptoms (17/35,48.6%) were the most common AEs; no patients reported grade 3 or 4 AEs. After surgery, 4 patients experienced chylothorax (4/33,12.1%). Patients with MPR had a prolonged survival compared with those without (DFS, P = .019).
Neoadjuvant therapy with gefitinib in patients with stage II-IIIA NSCLC is safe and may be a viable treatment for patients whose tumors have EGFR mutations. Patients with MPR were associated with improved survival.
Display omitted
•Copper species of Cu/SiO2 catalysts were tuned by hydrolysis precipitation method.•Higher dispersion of copper species and large ratio of Cu+/(Cu++Cu0) were obtained.•Superior catalytic performance ...was achieved for the hydrogenation of DMO to EG.•Cu+ plays key role in DMO hydrogenation on the as-prepared copper-based catalyst.
The chemoselective synthesis of ethylene glycol (EG) from the hydrogenation of dimethyl oxalate (DMO) derived from syngas is an attractive technology in the modern chemical industry. This work reported a novel hydrolysis precipitation (HP) method to efficiently tune the active copper species of Cu/SiO2 catalysts for DMO hydrogenation. Characterization techniques such as N2 physical adsorption, X-ray diffraction, H2 temperature programmed reduction, N2O titration, Fourier-transform infrared spectra, transmission electron microscopy, and X-ray photoelectron spectroscopy were employed to reveal the origin of the catalytic performances. Compared to the ammonia evaporation (AE) method, the HP method presented remarkable higher dispersion of copper species and large ratio of Cu+/(Cu++Cu0) on the catalyst surface, resulting in a superior catalytic performance in the hydrogenation of DMO to EG. Moreover, the amount of Cu0 and Cu+ sites on catalyst surface is dramatically affected by copper loading, and the catalyst with 30% copper showed the highest catalytic activity with a space time yield of 1.74gEG/(gcat·h) at 463K. Meanwhile, the positive correlation between Cu+ surface area and space time yield of EG suggests that the amount Cu+ is the key factor for hydrogenation of DMO to EG on the as-prepared Cu/SiO2 catalyst. The formation of more Cu+ species in the catalyst would enhance the activation of CO group in DMO and significantly improve the catalytic performances in DMO hydrogenation.
Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are the pre- and minimally invasive forms of lung adenocarcinoma. We aimed to investigate safety results and survival outcomes ...following different types of surgical resection in a large sample of patients with AIS/MIA.
Medical records of patients with lung AIS/MIA who underwent surgery between 2012 and 2017 were retrospectively reviewed. Clinical characteristics, surgical types and complications, recurrence-free survival, and overall survival were investigated.
A total of 1644 patients (422 AIS and 1222 MIA) were included. The overall surgical complication rate was significantly lower in patients receiving wedge resection (1.0%), and was comparable between patients undergoing segmentectomy (3.3%) or lobectomy (5.6%). Grade ≥ 3 complications occurred in 0.1% of patients in the wedge resection group, and in a comparable proportion of patients in the segmentectomy group (1.5%) and the lobectomy group (1.5%). There was no lymph node metastasis. The 5-year recurrence-free survival rate was 100%. The 5-year overall survival rate in the entire cohort was 98.8%, and was comparable among the wedge resection group (98.8%), the segmentectomy group (98.2%), and the lobectomy group (99.4%).
Sublobar resection, especially wedge resection without lymph node dissection, may be the preferred surgical procedure for patients with AIS/MIA. If there are no risk factors, postoperative follow-up intervals may be extended. These implications should be validated in further studies.
Display omitted
LiFePO
4
is still a promising cathode, which is inexpensive, nontoxic, environmentally benign, and most importantly safe. However, LiFePO
4
suffers from low conductivity and sluggish diffusion of ...lithium ions. Surface decoration, nanocrystallization and lattice substitution (doping) are modification approaches widely employed to promote the conductivity of electrons and the diffusion of lithium ions in the crystal lattices of LiFePO
4
. This review focuses on discussing the functional mechanisms of these optimization methods from the extent of electron and lithium ion migration and the features of LiFePO
4
, namely, its structure and phase transformation reactions. At the interface of LiFePO
4
and the electrolyte, decoration layers not only ensure the stability of LiFePO
4
by excluding HF corrosion and surface degradation, but also reduce charge transfer resistances for the surface reactions with fast lithium ions and electrons. When it comes to the lattices of LiFePO
4
, nanocrystallization unblocks the diffusion path, as well as shortens the diffusion length of lithium ions. Decoration layers in the inner surface avoid slowing down the diffusion of lithium ions in the lattices throughout the reactions and maximize the utilization of LiFePO
4
. Lattice substitutions, which increase the electronic conductivity by decreasing the band gap, interrupt the major advantage of LiFePO
4
, the structural stability, which guarantees the safety as well as the cycling and rate performances. To make the electrochemical performance of LiFePO
4
better and overcome the contradiction about the miscibility gaps, 010-oriented LiFePO
4
nanoflakes/nanomeshes/nanoplates, 100-oriented or 001-oriented nanorod/nanowire structures and nanowires/nanorods/nanotubes with a carbon/LiFePO
4
/carbon coaxial structure (graphically shown in the text) can be developed in the future.
This review discusses optimization methods for LiFePO
4
from the extent of electron and Li
+
migration and proposes two future optimization approaches.
An efficient homotype Ag3PO4/BiVO4 heterojunction photocatalyst is described. Ag3PO4 nanoparticles preferentially deposit on the highly active BiVO4(040) facets by means of heterojunction ...construction together with morphology engineering. The Ag3PO4/BiVO4 photocatalyst shows high charge separation efficiency as well as enhanced visible‐light response ability and thus possesses superior visible light photocatalytic activity.
During the process of seabed terrain exploration using a multi-beam echo system, it is inevitable to obtain a sounding set containing anomalous points. Conventional methods for eliminating outliers ...are unable to reduce the disruption caused by outliers over the whole dataset. Furthermore, incomplete consideration is given to the terrain complexity, error magnitude, and outlier distribution. In order to achieve both a high-precision terrain quality estimate and quick detection of depth anomalies, this study suggests a dual robust technique. Firstly, a robust polyhedral function is utilized to solve anomaly detection for large errors. Secondly, the robust kriging algorithm is used for refined outlier removal. Ultimately, the process of dual detection and anomaly removal is achieved. The experimental results demonstrate that DRS technology has the most favorable mean square error and error fluctuation range in the test set, with values of 0.8321 and -2.0582, 1.9209, respectively, when compared to RPF, WT, GF, and WLS-SVM schemes. Furthermore, DRS is able to adjust to various terrain complexities, discrete distribution features, and cluster outlier detection, as shown by objective indicators and visual outcome maps, guaranteeing a high-quality seabed terrain estimate.
Display omitted
•High efficient copper-based catalyst was prepared with ordered mesoporous silica as support precursor.•Appropriate pH value of the solution can ensure the high dispersion of copper ...species.•The presence of mesoporous structure enhanced the formation of copper phyllosilicate.•20Cu/OMS presented excellent catalytic performance in dimethyl oxalate hydrogenation.
A modified ammonia evaporation method with an ordered mesoporous silica as the precursor of the support was applied to prepare the well dispersed copper-based catalysts. Appropriate amount of ammonia was used during the aging stage to prevent the destruction of the ordered mesoporous structure, which can ensure the homogeneous pre-distribution of the copper precursor (Cu(NH3)42+) in the mesopores. Then the formation of copper phyllosilicate or surface Cu–O–Si species can be prompted during the ammonia evaporation stage, resulting in large surface areas of both Cu0 and Cu+ species in the final catalysts. It was also revealed that the formation of copper phyllosilicate led to the destruction of mesoporous silica structure in the ammonia evaporation stage especially at the higher copper loading. The catalysts with various copper loading were systematically characterized and applied in the hydrogenation of dimethyl oxalate to ethylene glycol (EG). An excellent low-temperature catalytic performance and stability were achieved on 20Cu/OMS with EG selectivity of 98.2% at 453K, due to the superior surface areas of both Cu0 and Cu+, as well as the highest ratio of Cu+/(Cu0+Cu+).
Objective
To develop a deep learning–based artificial intelligence (AI) scheme for predicting the likelihood of the ground-glass nodule (GGN) detected on CT images being invasive adenocarcinoma (IA) ...and also compare the accuracy of this AI scheme with that of two radiologists.
Methods
First, we retrospectively collected 828 histopathologically confirmed GGNs of 644 patients from two centers. Among them, 209 GGNs are confirmed IA and 619 are non-IA, including 409 adenocarcinomas in situ and 210 minimally invasive adenocarcinomas. Second, we applied a series of pre-preprocessing techniques, such as image resampling, rescaling and cropping, and data augmentation, to process original CT images and generate new training and testing images. Third, we built an AI scheme based on a deep convolutional neural network by using a residual learning architecture and batch normalization technique. Finally, we conducted an observer study and compared the prediction performance of the AI scheme with that of two radiologists using an independent dataset with 102 GGNs.
Results
The new AI scheme yielded an area under the receiver operating characteristic curve (AUC) of 0.92 ± 0.03 in classifying between IA and non-IA GGNs, which is equivalent to the senior radiologist’s performance (AUC 0.92 ± 0.03) and higher than the score of the junior radiologist (AUC 0.90 ± 0.03). The Kappa value of two sets of subjective prediction scores generated by two radiologists is 0.6.
Conclusions
The study result demonstrates using an AI scheme to improve the performance in predicting IA, which can help improve the development of a more effective personalized cancer treatment paradigm.
Key Points
• The feasibility of using a deep learning method to predict the likelihood of the ground-glass nodule being invasive adenocarcinoma.
• Residual learning–based CNN model improves the performance in classifying between IA and non-IA nodules.
• Artificial intelligence (AI) scheme yields higher performance than radiologists in predicting invasive adenocarcinoma.
