Defined cavities are found in biological systems, such as in enzymes to accelerate specific reactions with specific molecular targets, or as transport containers for molecular cargos. Chemists have ...been inspired by those phenomena found in nature and synthesized defined cage compounds for different purposes, such as for stabilizing reactive intermediates, running reactions within the cavities or studying recognition events. However, most cage compounds are based on the coordination of metal ions, and only a few are charge neutral. Purely organic cages are usually charge neutral and more stable due to existing covalent bonds. Covalent bonds can be made in two ways, applying irreversible reactions or reversible reactions. By introducing dynamic covalent chemistry (DCC), cages have become accessible in good yields from rather simple precursors. Here, we compare both methods and highlight those that give very good yields. Furthermore, the use of organic cage compounds in sorption, recognition, sensing, separation and stabilization of molecules will be discussed.
The synthesis of shape-persistent organic cage compounds
via
reversible and irreversible reactions as well as their use in stabilizing reactive intermediates, recognition of molecules and ions, sensing applications and gas sorption is discussed.
Catalytic conversion of renewable biomass to “green” chemicals and fuel additives has been extensively investigated in the past few decades. Interests on two top platform intermediates for biofuel ...production, i.e. levulinic acid (LA) and 5-hydroxymethylfurfural (HMF), have increased significantly. These two chemicals are generally produced from biomass through acid hydrolysis. This review summarizes the discoveries of the most recent studies on acid-catalyzed hydrolysis, including (i) biomass pretreatment, (ii) glucose production from cellulose hydrolysis, (iii) fructose formation from glucose isomerization, (iv) HMF formation from glucose/fructose dehydration and (v) LA production from HMF rehydration. Humins, the main byproducts, are also discussed in the aspect of their influence on the hydrolysis process, structure, formation mechanism, and applications.
•Reaction mechanism of lignocellulosic biomass to levulinic acid is reviewed.•Challenges for commercial production of 5-hydroxymethylfurfural are studied.•The feasibility of commercial production of levulinic acid is discussed.•Value added conversion pathways of waste hummis are proposed.•Future research direction on biomass acid hydrolysis is recommended.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
At present, the posterior probability measure widely used in English speech recognition has the situation that the posterior probability measure of different phonemes cannot be consistent to measure ...the pronunciation quality of the phoneme and the acoustic modeling method of voice recognition is inconsistent with the evaluation target. Therefore, in order to improve the evaluation effect of English pronunciation quality in colleges and universities, this article is based on artificial emotion recognition and high-speed hybrid model to analyze and filter various clutters that affect speech quality to improve students’ English speech recognition. Moreover, this article uses the characteristics of the clutter and the target in the data to conform to different distributions and based on the clutter distribution characteristics obtained by statistics, this article realizes the suppression of the clutter to improve the target detection performance. In addition, the method proposed in this paper solves the limitations of the clutter suppression technology in the traditional voice detection system and improves the target detection performance. In order to study the pronunciation quality evaluation effect of this model and its effect in English teaching, this paper designs a controlled experiment to analyze the model’s performance. The research results show that the model constructed in this paper has good performance.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Thermoelectric (TE) materials provide a solid‐state solution in waste heat recovery and refrigeration. During the past few decades, considerable effort has been devoted towards improving the ...performance of TE materials, which requires the optimization of multiple interrelated properties. A fundamental understanding of the interaction processes between the various energy carriers, such as electrons and phonons, is critical for advances in the development of TE materials. However, this understanding remains challenging primarily due to the inaccessibility of time scales using standard atomistic simulations. Machine learning methods, well known for their data‐analysis capability, have been successfully applied in research on TE materials in recent years. Here, an overview of the machine learning methods used in thermoelectric studies is provided, with the role that each machine learning method plays being systematically discussed. Furthermore, to date, the scale of thermoelectric‐related databases is much smaller than those in other fields, such as e‐commerce, image identification, and speech recognition. To overcome this limitation, possible strategies to utilize small databases in promoting materials science are also discussed. Finally, a brief conclusion and outlook are presented.
Thermoelectric materials provide a solid‐state solution in waste heat recovery and refrigeration. A fundamental understanding of the interaction processes between electrons and phonons still remains challenging. An overview of the machine learning methods used in thermoelectric studies is provided, and the role that each machine learning method plays is systematically discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Psychological health problems, especially emotional disorders, are common among adolescents. The epidemiology of emotional disorders is greatly influenced by stressful events. This study sought to ...assess the prevalence rate and socio-demographic correlates of depressive and anxiety symptoms among Chinese adolescents affected by the outbreak of COVID-19. We conducted a cross-sectional study among Chinese students aged 12–18 years during the COVID-19 epidemic period. An online survey was used to conduct rapid assessment. A total of 8079 participants were involved in the study. An online survey was used to collect demographic data, assess students’ awareness of COVID-19, and assess depressive and anxiety symptoms with the Patient Health Questionnaire (PHQ-9) and the Generalized Anxiety Disorder (GAD-7) questionnaire, respectively. The prevalence of depressive symptoms, anxiety symptoms, and a combination of depressive and anxiety symptoms was 43.7%, 37.4%, and 31.3%, respectively, among Chinese high school students during the COVID-19 outbreak. Multivariable logistic regression analysis revealed that female gender was the higher risk factor for depressive and anxiety symptoms. In terms of grades, senior high school was a risk factor for depressive and anxiety symptoms; the higher the grade, the greater the prevalence of depressive and anxiety symptoms. Our findings show there is a high prevalence of psychological health problems among adolescents, which are negatively associated with the level of awareness of COVID-19. These findings suggest that the government needs to pay more attention to psychological health among adolescents while combating COVID-19.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, ODKLJ, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
Using first-principles calculations and deformation potential theory, we investigate the intrinsic carrier mobility (μ) of monolayer MoS2 sheet and nanoribbons. In contrast to the dramatic ...deterioration of μ in graphene upon forming nanoribbons, the magnitude of μ in armchair MoS2 nanoribbons is comparable to its sheet counterpart, albeit oscillating with ribbon width. Surprisingly, a room-temperature transport polarity reversal is observed with μ of hole (h) and electron (e) being 200.52 (h) and 72.16 (e) cm2 V–1 s–1 in sheet, and 49.72 (h) and 190.89 (e) cm2 V–1 s–1 in 4 nm nanoribbon. The high and robust μ and its polarity reversal are attributable to the different characteristics of edge states inherent in MoS2 nanoribbons. Our study suggests that width reduction together with edge engineering provide a promising route for improving the transport properties of MoS2 nanostructures.
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IJS, KILJ, NUK, PNG, UL, UM
Although mRNA vaccines have been effective against multiple cancers, their efficacy against pancreatic adenocarcinoma (PAAD) remains undefined. Accumulating evidence suggests that immunotyping can ...indicate the comprehensive immune status in tumors and their immune microenvironment, which is closely associated with therapeutic response and vaccination potential. The aim of this study was to identify potent antigens in PAAD for mRNA vaccine development, and further distinguish immune subtypes of PAAD to construct an immune landscape for selecting suitable patients for vaccination.
Gene expression profiles and clinical information of 239 PAAD datasets were extracted from ICGC, and RNA-Seq data of 103 samples were retrieved from TCGA. GEPIA was used to calculate differential expression levels and prognostic indices, cBioPortal program was used to compare genetic alterations, and TIMER was used to explore correlation between genes and immune infiltrating cells. Consensus cluster was used for consistency matrix construction and data clustering, DAVID was used for functional annotation, and graph learning-based dimensional reduction was used to depict immune landscape.
Six overexpressed and mutated tumor antigens associated with poor prognosis and infiltration of antigen presenting cells were identified in PAAD, including ADAM9, EFNB2, MET, TMOD3, TPX2, and WNT7A. Furthermore, five immune subtypes (IS1-IS5) and nine immune gene modules of PAAD were identified that were consistent in both patient cohorts. The immune subtypes showed distinct molecular, cellular and clinical characteristics. IS1 and IS2 exhibited immune-activated phenotypes and correlated to better survival compared to the other subtypes. IS4 and IS5 tumors were immunologically cold and associated with higher tumor mutation burden. Immunogenic cell death modulators, immune checkpoints, and CA125 and CA199, were also differentially expressed among the five immune subtypes. Finally, the immune landscape of PAAD showed a high degree of heterogeneity between individual patients.
ADAM9, EFNB2, MET, TMOD3, TPX2, and WNT7A are potent antigens for developing anti-PAAD mRNA vaccine, and patients with IS4 and IS5 tumors are suitable for vaccination.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The mRNA-based cancer vaccine has been considered a promising strategy and the next hotspot in cancer immunotherapy. However, its application on cholangiocarcinoma remains largely uncharacterized. ...This study aimed to identify potential antigens of cholangiocarcinoma for development of anti-cholangiocarcinoma mRNA vaccine, and determine immune subtypes of cholangiocarcinoma for selection of suitable patients from an extremely heterogeneous population.
Gene expression profiles and corresponding clinical information were collected from GEO and TCGA, respectively. cBioPortal was used to visualize and compare genetic alterations. GEPIA2 was used to calculate the prognostic index of the selected antigens. TIMER was used to visualize the correlation between the infiltration of antigen-presenting cells and the expression of the identified antigens. Consensus clustering analysis was performed to identify the immune subtypes. Graph learning-based dimensionality reduction analysis was conducted to visualize the immune landscape of cholangiocarcinoma.
Three tumor antigens, such as CD247, FCGR1A, and TRRAP, correlated with superior prognoses and infiltration of antigen-presenting cells were identified in cholangiocarcinoma. Cholangiocarcinoma patients were stratified into two immune subtypes characterized by differential molecular, cellular and clinical features. Patients with the IS1 tumor had immune "hot" and immunosuppressive phenotype, whereas those with the IS2 tumor had immune "cold" phenotype. Interestingly, patients with the IS2 tumor had a superior survival than those with the IS1 tumor. Furthermore, distinct expression of immune checkpoints and immunogenic cell death modulators was observed between different immune subtype tumors. Finally, the immune landscape of cholangiocarcinoma revealed immune cell components in individual patient.
CD247, FCGR1A, and TRRAP are potential antigens for mRNA vaccine development against cholangiocarcinoma, specifically for patients with IS2 tumors. Therefore, this study provides a theoretical basis for the anti-cholangiocarcinoma mRNA vaccine and defines suitable patients for vaccination.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The 5+2 cycloaddition is one kind of fascinating and powerful reaction to access seven-membered ring systems existing in complex natural products and pharmaceuticals. In this review, recent ...developments on the 5+2 cycloadditions and their application in the synthesis of complex natural products are discussed. A focus is given to the way in which the 5+2 cycloadditions have influenced the logical process of the synthesis. This article is organized by reaction types, aiming to provide a clear clue to the latest research trends.
The recent developments on the 5+2 cycloadditions and their application in the synthesis of complex natural products are discussed.
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