The exploitation of new materials for adsorptive separation of industrially important hydrocarbons is of great importance in both scientific research and petrochemical industry. Nonporous adaptive ...crystals (NACs) as a robust class of synthetic materials have drawn much attention during the past five years for their superior performance in adsorption and separation. Pillararenes are the main family of macrocyclic arenes used for NACs construction, where the structure–function relationship has been intensively studied. In the past two years, some emerging types of synthetic macrocyclic arenes have been successfully brought into this research field, showing the gradual enrichment and diversification of NACs materials. This Minireview summarizes the recent advances of synthetic macrocycle‐based NACs, which are categorized by various practical applications in molecular separation. Besides, NACs‐based vapochromic supramolecular systems are also discussed. Finally, future perspectives and challenges of NACs are given. We envisage that this Minireview will be a useful and timely reference for those who are interested in new molecular and supramolecular crystals for storage and separation applications.
This Minireview describes the recent advances of synthetic macrocycle‐based nonporous adaptive crystals for molecular separation and vapochromic application.
Haloalkanes are important chemicals in synthetic chemistry and petrochemical industry, but the separation of their isomers is a big hurdle. Herein, we report a facile energy‐efficient adsorptive ...separation strategy using a new class of nonporous adaptive crystals based on leaning pillar6arene. Desolvated perethylated leaning pillar6arene crystals (EtLP6) with interesting nonporous character show a preference for 1‐bromoalkane isomers over 2‐bromoalkane isomers. EtLP6 is capable of separating 1‐bromopropane, 1‐bromobutane, and 1‐bromopentane from the corresponding 1:1 (v/v) mixtures of 1/2‐positional isomers with purities from 89.6 % to 96.3 % in only one adsorption cycle. The selectivity is endowed by the different host–guest binding modes and different stabilities of EtLP6 crystalloids loaded with 1‐ and 2‐positional isomers. Significantly, the guest–adsorbed assemblies are highly stable at room temperature and EtLP6 can be reused many times without any decrease in performance.
The separation of haloalkane isomers is of high practical value in both synthetic chemistry and petrochemical industry. Herein, a simple‐operating and energy‐efficient separation method by using nonporous leaning towerarene crystals to separate bromoalkane isomers is provided.
Synthetic macrocycles have served as principal tools for supramolecular chemistry, have greatly extended the scope of organic charge transfer (CT) complexes, and have proved to be of great practical ...value in the solid state during the past few years. In this Minireview, we summarize the research progress on the macrocycle‐based crystalline supramolecular assemblies primarily driven by intermolecular CT interactions (a.k.a. macrocycle‐based crystalline CT assemblies, MCCAs for short), which are classified by their donor–acceptor (D‐A) constituent elements, including simplex macrocyclic hosts, heterogeneous macrocyclic hosts, and host–guest D‐A pairs. Particular attention will be focused on their diverse functions and applications, as well as the underlying CT mechanisms from the perspective of crystal engineering. Finally, the remaining challenges and prospects are outlined.
This Minireview highlights the advancements in the field of macrocycle‐based crystalline charge‐transfer assemblies, including their preparation, structures, and diverse supramolecular functions and applications, such as vapochromic behavior and supramolecular tessellations, arising from the CT state. Future perspectives and challenges of this emerging research field are also presented.
The response rates of online surveys were often examined in the literature by comparing to other modes of surveys. Questions regarding what constitutes a respectable response rate for online surveys ...in research remained unanswered. To fill in the knowledge gap, we conducted a comprehensive search, screened 8672 studies, and examined 1071 online survey response rates reported in education-related research. Our analyses showed the number of online surveys in published research grew steadily across the years. The average online survey response rate is 44.1%. Our results indicate that sending an online survey to more participants did not generate a higher response rate. Instead, sending surveys to a clearly defined and refined population positively impacts the online survey response rate. In addition, pre-contacting potential participants, using other types of surveys in conjunction with online surveys, and using phone calls to remind participants about the online survey could also yield a higher response rate. The use of incentives did not show a significant impact on the response rate of online surveys. Other factors that impacted the rates included the funding status of a project, and the age and occupation of the participants. Concrete suggestions for reviewing and improving the online survey response rates are provided.
Incorporating synthetic macrocycles with unique structures and distinct conformations into conjugated macrocycle polymers (CMPs) can endow the resulting materials with great potentials in gas uptake ...and pollutant adsorption. Here, four CMPs (CMP‐n, n=1–4) capable of reversibly capturing iodine and efficiently separating carbon dioxide are constructed from per‐triflate functionalized leaning tower6arene (LT6‐OTf) and 2biphenyl‐extended pillar6arene (BpP6‐OTf) via Pd‐catalyzed Sonogashira–Hagihara cross‐coupling reaction. Intriguingly, owing to the appropriate cavity size of LT6‐OTf and the numerous aromatic rings in the framework, the newly designed CMP‐4 possesses an outstanding I2 affinity with a large uptake capacity of 208 wt % in vapor and a great removal efficiency of 94 % in aqueous solutions. To our surprise, with no capacity to accommodate nitrogen, CMP‐2 constructed from BpP6‐OTf is able to specifically capture carbon dioxide at ambient conditions.
Four catcher‐type conjugated macrocycle polymers (CMP‐n, n=1–4) have been designed and synthesized successfully, exhibiting interesting application in CO2 and I2 uptake. The CMP‐2 is able to capture CO2 with excellent selectivity and the CMP‐4 is capable of adsorbing iodine with outstanding capacity.
Given the comparatively lower rotational barriers, the catalytic asymmetric construction of axially chiral biaryl structures, especially those containing a five‐membered heterocycle, still remains a ...challenge. Herein, we described a general and modular protocol to access atropisomeric arylpyrazole scaffolds containing a phosphorus unit by a dipeptide phosphonium salt catalyzed reaction involving an oxidative central‐to‐axial chirality conversion. This reaction features excellent yields and enantioselectivities, broad substrate scope, and a low catalyst loading, delivering axially chiral phosphine compounds.
A highly enantioselective reaction has been developed for the construction of axially chiral arylpyrazole skeletons with phosphorus unit. The reaction proceeds through a sequential Huisgen‐type cycloaddition/aromatization process with central‐to‐axial chirality conversion using a dipeptide‐phosphonium salt catalyst. Arylpyrazole‐based atropisomeric phosphorus compounds are obtained in high yields with excellent enantioselectivities.
Due to its simplicity, efficiency, and efficacy, naive Bayes (NB) has continued to be one of the top 10 algorithms in the data mining and machine learning community. Of numerous approaches to ...alleviating its conditional independence assumption, feature weighting has placed more emphasis on highly predictive features than those that are less predictive. In this paper, we argue that for NB highly predictive features should be highly correlated with the class (maximum mutual relevance), yet uncorrelated with other features (minimum mutual redundancy). Based on this premise, we propose a correlation-based feature weighting (CFW) filter for NB. In CFW, the weight for a feature is a sigmoid transformation of the difference between the feature-class correlation (mutual relevance) and the average feature-feature intercorrelation (average mutual redundancy). Experimental results show that NB with CFW significantly outperforms NB and all the other existing state-of-the-art feature weighting filters used to compare. Compared to feature weighting wrappers for improving NB, the main advantages of CFW are its low computational complexity (no search involved) and the fact that it maintains the simplicity of the final model. Besides, we apply CFW to text classification and have achieved remarkable improvements.
CRISPR/Cas9 is a valuable tool for both basic and applied research that has been widely applied to different plant species. Nonetheless, a systematical assessment of the efficiency of this method is ...not available for the allotetraploid Brassica napus-an important oilseed crop. In this study, we examined the mutation efficiency of the CRISPR/Cas9 method for 12 genes and also determined the pattern, specificity and heritability of these gene modifications in B. napus. The average mutation frequency for a single-gene targeted sgRNA in the T0 generation is 65.3%. For paralogous genes located in conserved regions that were targeted by sgRNAs, we observed mutation frequencies that ranged from 27.6% to 96.6%. Homozygotes were readily found in T0 plants. A total of 48.2% of the gene mutations, including homozygotes, bi-alleles, and heterozygotes were stably inherited as classic Mendelian alleles in the next generation (T1) without any new mutations or reversions. Moreover, no mutation was found in the putative off-target sites among the examined T0 plants. Collectively, our results demonstrate that CRISPR/Cas9 is an efficient tool for creating targeted genome modifications at multiple loci that are stable and inheritable in B. napus. These findings open many doors for biotechnological applications in oilseed crops.
Despite the significance of chiral allene skeletons in catalysis, organic synthesis and medicinal chemistry et al., there is a scarcity of reports on axially chiral allenyl phosphorus compounds. ...Here, we disclosed an efficient and straightforward cascade reaction between ethynyl ketones and phosphine oxides, resulting in a broad array of trisubstituted allenes incorporating a phosphorus moiety in high yields with excellent stereoselectivities facilitated by peptide‐mimic phosphonium salt (PPS) catalysis, Additionally, comprehensive series of mechanistic experiments have been conducted to elucidate that this cascade reaction proceeds via an asymmetric Pudovik addition reaction followed by a subsequent phospha‐Brook rearrangement that occurs concomitantly with kinetic resolution, representing a stereospecific rearrangement and protonation process facilitating central‐to‐axial chirality transfer in a cascade manner. We anticipate that our research will pave the way for a promising exploration of novel stereo‐induction pattern in the Pudovik addition/phospha‐Brook rearrangement cascade reaction.
An efficient and practical methodology has been developed to synthesize axially chiral phosphorus allenes through a PPS‐catalyzed asymmetric Pudovik addition followed by phospha‐Brook rearrangement. Mechanistic experiments have demonstrated that the enantio‐determining step is the 1,2‐addition, with the subsequent rearrangement undergoing a central‐to‐axial chirality transfer.
Ferroptosis is a recently defined form of cell death with the involvement of iron and reactive oxygen species (ROS), which is distinct from apoptosis, autophagy and other forms of cell death. ...Emerging evidence suggested that iron accumulation and lipid peroxidation can be discovered in various neurological diseases, accompanied with reduction of glutathione (GSH) and glutathione peroxidase 4 (GPX4). In addition, ferroptotic inhibitors have been shown to protect neurons, and recover the cognitive function in disease animal models. This review summarizes the mechanisms underlying ferroptosis and reviews the contributions of ferroptosis in neurodegenerative diseases (i.e. Alzheimer’s disease and Parkinson’s disease), traumatic brain injury, as well as hemorrhagic and ischemic stroke, to provide the current understanding of this novel form of cell death in neurological disorders.
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