The photochemical reaction of peroxy radical (RO2·) and NO has been identified by field and forest studies as important source of organic nitrates (RONO2) in the atmosphere. However, this traditional ...pathway is not sufficient to explain the high concentration of RONO2. Hence, a new source of the tropospheric RONO2 from the dark reactions of nitric acid (HNO3) with aliphatic aldehydes (C1–C5) under catalysis is provided and examined for the first time by high-level quantum chemistry. The findings show that the reaction between HCHO and HNO3, which produces HOCH2ONO2, can be catalyzed by a series of metal-free catalysts (NH3, CH3NH2, CH3NHCH3, H2O, HNO3, H2SO4, HCOOH, HOOCCOOH). At 296 K, the effective rate constant for the bimolecular HNO3–HCHO reaction under the catalysis of CH3NH2 or CH3NHCH3 can be sufficiently accelerated by 5–8 order of magnitudes through this new loss pathway for HNO3 or HCHO to become competitive with the conventional loss pathway for their photochemical reactions with ·OH radical. Significantly, this new HOCH2ONO2 formation pathway from the dark reaction of HCHO with CH3NH3+NO3−/(CH3)2NH + NO3− was more favorable than the recognized source of RO2· with NO. Efficient catalysis performance of CH3NH2 and CH3NHCH3 is mainly attributed to their excellent proton receptivity capacity by activating the O–H bond of HNO3 to form stable organic nitrates (CH3NH3+NO3− and (CH3)2NH + NO3−) in the rate-determining step transition states. In the case of only considering the barrier, H2SO4 is the best catalyst among the investigated inorganic and organic acids, and dicarboxylic acid (HOOCCOOH) is stronger than monocarboxylic acid HCOOH in facilitating the RONO2 formation reaction. These new findings deepen our understanding on the unexpected source of organic nitrate and loss pathway of HNO3 or HCHO under catalysis in highly polluted regions.
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•Kinetics and mechanism for reactions of HNO3 with C1–C5 aliphatic aldehydes were studied.•Role of water, acids, and alkalies on the HNO3/HCHO reaction were analyzed.•A new loss pathway for HCHO was identified via amine-catalyzed HNO3/HCHO reaction.•An unexpected source of RONO2 with the help of catalysts was proposed and verified.•The proposed new source of RONO2 was more favorable than that of RO2·/NO reaction.
Highlights • OLF is a major cause of acquired thoracic spinal canal stenosis. • Surgical intervention is generally necessary for symptomatic thoracic OLF. • Posterior decompressive laminectomy is ...effective for symptomatic thoracic OLF. • Surgery for thoracic OLF had a relatively high risk of complications.
Glycosylated hemoglobin (HbA1c) is recommended for diagnosing and monitoring type 2 diabetes. However, the monitoring frequency in real-world applications has not yet reached the recommended ...frequency in the guidelines. Developing machine learning models to screen patients with poor glycemic control in patients with T2D could optimize management and decrease medical service costs.
This study was carried out on patients with T2D who were examined for HbA1c at the Sichuan Provincial People's Hospital from April 2018 to December 2019. Characteristics were extracted from interviews and electronic medical records. The data (excluded FBG or included FBG) were randomly divided into a training dataset and a test dataset with a radio of 8:2 after data pre-processing. Four imputing methods, four screening methods, and six machine learning algorithms were used to optimize data and develop models. Models were compared on the basis of predictive performance metrics, especially on the model benefit (MB, a confusion matrix combined with economic burden associated with therapeutic inertia). The contributions of features were interpreted using SHapley Additive exPlanation (SHAP). Finally, we validated the sample size on the best model.
The study included 980 patients with T2D, of whom 513 (52.3%) were defined as positive (need to perform the HbA1c test). The results indicated that the model trained in the data (included FBG) presented better forecast performance than the models that excluded the FBG value. The best model used modified random forest as the imputation method, ElasticNet as the feature screening method, and the LightGBM algorithms and had the best performance. The MB, AUC, and AUPRC of the best model, among a total of 192 trained models, were 43475.750 (¥), 0.972, 0.944, and 0.974, respectively. The FBG values, previous HbA1c values, having a rational and reasonable diet, health status scores, type of manufacturers of metformin, interval of measurement, EQ-5D scores, occupational status, and age were the most significant contributors to the prediction model.
We found that MB could be an indicator to evaluate the model prediction performance. The proposed model performed well in identifying patients with T2D who need to undergo the HbA1c test and could help improve individualized T2D management.
Phononic crystals that prevent the propagation of waves in a band gap have been widely applied in wave propagation control. In this paper, we propose the use of a metabarrier, based on a locally ...resonant phononic crystal mechanism, as a floating-slab track bearing to shield the infrastructure in a floating-slab track system from longitudinal waves from the slab, thereby improving mitigation of ground-borne vibrations. The locally resonant band gap properties of the metabarrier were studied based on the finite element method, and the shielding performance was verified by the transmission spectrum. Simplified models for band gap boundary frequencies were built according to the wave modes. Furthermore, a 3D half-track model was built to investigate the overall vibration mitigation performance of the floating-slab track with the metabarrier. An optimization mechanism for the band gap boundary frequencies is proposed. As the low-frequency ground-borne vibrations induced by subways carry the most energy, multi-objective genetic algorithm optimization was conducted to obtain a lower and wider band gap for a better shielding performance. The results show that the retained vibration isolation performance of the low natural frequency, the shielding performance of the band gap, and the controllability of band gap boundary frequencies all contribute to an improvement in overall vibration mitigation performance. The vertical static stiffness of the metabarrier was close to that of the existing bearing of the floating-slab track. An optimized locally resonant band gap from 50 to 113 Hz was generated using the optimization mechanism.
Pancreatic adenocarcinoma has an exceedingly poor prognosis, accounting for five-year survival of less than 5%. Presently, improving the efficacy of pancreatic adenocarcinoma treatment has been the ...focus of medical researchers worldwide. Recently, it has been suggested that deregulation of interleukin- (IL-) 6 is caused by a key gene involved in the beginning and development of pancreatic adenocarcinoma. Herein, we investigated whether suppression of IL-6 could augment gemcitabine sensitivity in the PANC-1 cells. We found considerably higher expression of IL-6 in pancreatic adenocarcinoma tissues than that in the adjacent nontumorous tissues. Suppression of IL-6 by shRNA resulted in apoptosis as well as inhibition of cell proliferation and tumorigenicity. In addition, suppression of IL-6 remarkably promoted antitumor effect of gemcitabine, indicating that the combination of shRNA targeting IL-6 with gemcitabine may provide a potential clinical approach for pancreatic cancer therapy.
Herein, the efficient photoredox/nickel dual-catalyzed cyanoalkylation reaction of enamides is illustrated. A wide scope of enamides and cycloketone oxime esters was well-tolerated, affording the ...synthetically versatile and geometrically defined β-cyanoalkylated enamide scaffolds. The synthetic practicality of this protocol was revealed by gram-scale reactions, further transformations of enamides, and late-stage modifications of biologically active molecules.
Transition metal oxides with the merits of high theoretical capacities, natural abundance, low cost, and environmental benignity have been regarded as a promising anodic material for lithium ion ...batteries (LIBs). However, the severe volume expansion upon cycling and poor conductivity limit their cycling stability and rate capability. To address this issue, NiO embedded and N-doped porous carbon nanorods (NiO@NCNR) and nanotubes (NiO@NCNT) are synthesized by the metal-catalyzed graphitization and nitridization of monocrystalline Ni(II)-triazole coordinated framework and Ni(II)/melamine mixture, respectively, and the following oxidation in air. When applied as an anodic material for LIBs, the NiO@NCNR and NiO@NCNT hybrids exhibit a decent capacity of 895/832 mA h g–1 at 100 mA g–1, high rate capability of 484/467 mA h g–1 at 5.0 A g–1, and good long-term cycling stability of 663/634 mA h g–1 at 600th cycle at 1 A g–1, which are much better than those of NiO@carbon black (CB) control sample (701, 214, and 223 mA h g–1). The remarkable electrochemical properties benefit from the advanced nanoarchitecture of NiO@NCNR and NiO@NCNT, which offers a length-controlled one-dimensional porous carbon nanoarchitecture for effective e–/Li+ transport, affords a flexible carbon skeleton for spatial confinement, and forms abundant nanocavities for stress buffering and structure reinforcement during discharge/charging processes. The rational structural design and synthesis may pave a way for exploring advanced metal oxide based anodic materials for next-generation LIBs.
To improve the sulfur loading capacity of lithium-sulfur batteries (Li-S batteries) cathode and avoid the inevitable “shuttle effect”, hollow N doped carbon coated CoO/SnO
2
(CoO/SnO
2
@NC) composite ...has been designed and prepared by a hydrothermal-calcination method. The specific surface area of CoO/SnO
2
@NC composite is 85.464 m
2
·g
−1
, and the pore volume is 0.1189 cm
3
·g
−1
. The hollow core-shell structure as a carrier has a sulfur loading amount of 66.10%. The initial specific capacity of the assembled Li-S batteries is 395.7 mAh·g
−1
at 0.2 C, which maintains 302.7 mAh·g
−1
after 400 cycles. When the rate increases to 2.5 C, the specific capacity still has 221.2 mAh·g
−1
. The excellent lithium storage performance is attributed to the core-shell structure with high specific surface area and porosity. This structure effectively increases the sulfur loading, enhances the chemical adsorption of lithium polysulfides, and reduces direct contact between CoO/SnO
2
and the electrolyte.
•A novel renewable furan-based phosphorus (PFPA) is synthesized.•Multifunctional bio-based PFPA is a good nucleating agent and fire-retardant for PLA.•A V-0 classification in UL-94 and LOI result of ...30.7 % for PLA with only loading 3 wt% PFPA are achieved.•The anti-flammability mechanism for PFPA in PLA is displayed.
Aiming to develop the crystallization and anti-flammability additives for creating high performance PLA, in this paper, a novel multifunctional bio-based furan derivative phenyl P-(N-N'-di-(furan-2-ylmethyl))phosphonamidate (PFPA) is synthesized and then is incorporated into PLA to enhance its comprehensive properties. The low loading of multifunctional bio-based PFPA not only as the nucleating agent increases the crystallinity and crystallization rate for PLA matrix, but also significantly improves anti-flammability properties of PLA. The V-0 classification in UL-94 and LOI result of 30.7 % for PLA with only loading 3 wt% PFPA are achieved. Moreover, the heat release values in cone-calorimeter measurement of PLA/3%PFPA composites are obviously decreased. The anti-flammability mechanism displays that PFPA forms highly-efficient fire-retardant radicals, accelerates heat away, suppresses combustible gases, and enhances stable residual carbon during PLA/PFPA combustion. This work provides a facile and efficient strategy for preparing multifunctional bio-based additives crystallization and fire-safety agent for PLA as well as promises broad application in engineering materials.
Various genetic and biochemical characteristics exist in tea plant cultivars, and they largely determine production suitability and tea quality. Here, we performed transcriptomic and metabolomic ...analyses of young shoots of seven tea cultivars and identified major regulatory transcription factors (TFs) for the characteristic metabolites in different cultivars based on weighted gene co-expression network analysis (WGCNA). Phenotypically, we found that ‘Tieguanyin’ (TGY) and ‘Fujian Shuixian’ (FJSX), which are suitable for oolong tea, had higher catechin contents. The metabolites of ‘Jinxuan’ (JX) were more prominent, especially the contents of phenolic acids, flavonoids, terpenes, and tannins, which were higher than those of the other six cultivars. Moreover, ‘Fudingdabai’ (FDDB), which is suitable for white tea, was rich in amino acids, linolenic acid, and saccharides. At the molecular level, hydroxycinnamoyl CoA quinate hydroxycinnamoyl transferase (HCT) (CsTGY12G0001876, and CsTGY06G0003042) led to the accumulation of chlorogenic acid in TGY. The main reason for the higher l-ascorbic acid content in FJSX was the high expression levels of L-galactono-1,4-lactone hydrogenase (GalLDH) (CsTGY13G0000389) and Myo-inositol oxygenase (MIOX) (CsTGY14G0001769, and CsTGY14G0001770), which were regulated by WRKY (CsTGY11G0001197). Furthermore, FDDB, ‘Longjing 43’ (LJ43), ‘Shuchazao’ (SCZ) and ‘Baihaozao’ (BHZ) had higher free fatty acid contents, among which MYB (CsTGY14G0002344) may be a hub gene for the regulation of palmitoleic acid accumulation. More importantly, we found that the shoots of TGY were green with purple, mainly due to the accumulation of anthocyanins and the downregulation of the Mg-protoporphyrin IX nonomethyl ester cyclase (MPEC) (CsTGY10G0001989) gene that affects chlorophyll synthesis. These results will provide a theoretical reference for tea cultivar breeding and suitability.
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