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The current standard treatment for locally advanced squamous cell carcinoma of the head and neck (LASCCHN) comprises concurrent radiotherapy (CRT) alongside platinum-based chemotherapy. However, innovative therapeutic alternatives are being evaluated in phase II/III randomized trials. This study employed a Bayesian network meta-analysis (NMA) using fixed effects to provide both direct and indirect comparisons of all existing treatment modalities for unresectable LASCCHN. METHODS: We referenced randomized controlled trials (RCTs) from January 2000 to July 2023 by extensively reviewing PubMed, EMBASE, and Web of Science databases, adhering to the Cochrane methodology. Relevant data, including summary estimates of overall survival (OS) and progression-free survival (PFS), were extracted from these selected studies and recorded in a predefined database sheet. Subsequently, we conducted a random effects network meta-analysis using a Bayesian framework. RESULTS: Based on the Surface Under the Cumulative Ranking (SUCRA) values, the league table organizes the various treatments for OS in the following order: IC + RT&MTT, MTT-CRT, IC + CRT&MTT, CRT, IC + CRT, MTT-RT, IC + MTT-RT, and RT. In a similar order, the treatments rank as follows according to the league table: IC + CRT&MTT, MTT-CRT, IC + CRT, IC + RT&MTT, CRT, IC + MTT-RT, MTT-RT, and RT. Notably, none of these treatments showed significant advantages over concurrent chemoradiotherapy. CONCLUSION: Despite concurrent chemoradiotherapy being the prevailing treatment for LASCCHN, our findings suggest the potential for improved outcomes when concurrent chemoradiotherapy is combined with targeted therapy or induction chemotherapy.
The current standard treatment for advanced head and neck cancer involves combining radiation therapy with chemotherapy. However, there are ongoing trials exploring alternative therapies. In this study, we conducted a comprehensive analysis of existing treatments using a statistical method called network meta-analysis. Our analysis included data from randomized controlled trials published between January 2000 and July 2023. We focused on overall survival and progression-free survival as key outcome measures. The results of our analysis showed that none of the alternative treatments demonstrated significant advantages over the standard concurrent chemoradiotherapy. Nevertheless, there is potential for improved outcomes when targeted therapy or induction chemotherapy is combined with concurrent chemoradiotherapy.
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Neoplasias de Cabeça e Pescoço , Metanálise em Rede , Carcinoma de Células Escamosas de Cabeça e Pescoço , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço/terapia , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/terapia , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Quimiorradioterapia/métodos , Teorema de Bayes , Ensaios Clínicos Controlados Aleatórios como Assunto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêuticoRESUMO
A semi-packed gas chromatographic column has the advantages of high specific surface area and low column pressure. We report that the stagnation regions formed in the adjacent posts along the channel of the semi-packed columns can decrease the area and height of chromatographic peaks, which makes it difficult to detect low-concentration mixed gases. A semi-packed column with staggered elliptic cylindrical post arrays (SC-S) made using a micro-electro-mechanical system technique is presented, and the separation performance of SC-S is compared with that of a semi-packed column with aligned elliptic cylindrical post arrays (SC-A). The simulation results show that the width of stagnation regions in SC-S is 86.89% smaller than that in SC-A. The experimental results indicate that the area and height of chromatographic peaks increased as stagnation regions reduced. In the separation of the alkane mixture from C8 through C10 with 10 ppm concentration, the chromatographic peak of decane was hardly identified in SC-A while the chromatographic peak in SC-S was still clearly visible. The chromatographic peak heights of octane and nonane were increased by 65.06% and 130.00%, respectively, in SC-S. The peak areas of octane and nonane were increased by 120.45% and 168.18%, respectively.
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The crystal growth kinetics is crucial for the controllable preparation and performance modulation of metal nanocrystals (NCs). However, the study of growth mechanisms is significantly limited by characterization techniques, and it is still challenging to in situ capture the growth process. Real-time and real-space imaging techniques at the atomic scale can promote the understanding of microdynamics for NC growth. Herein, the growth of Pd NCs on monolayer MoS2 under different atmospheres was in situ studied by environmental transmission electron microscopy. Introducing carbon monoxide can modulate the diffusion of Pd monomers, resulting in the epitaxial growth of Pd NCs with a uniform orientation. The electron energy loss spectroscopy and theoretical calculations showed that the CO adsorption assured the specific exposed facets and good uniformity of Pd NCs. The insight into the gas-solid interface interaction and the microscopic growth mechanism of NCs may shed light on the precise synthesis of NCs on two-dimensional (2D) materials.
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The theory of kidney storing essence storage, an important part of the basic theory of traditional Chinese medicine(TCM), comes from the Chapter 9 Discussion on Six-Plus-Six System and the Manifestations of the Viscera in the Plain Questions, which says that "the kidney manages closure and is the root of storage and the house of Jing(Essence)". According to this theory, essence is the fundamental substance of human life activities and it is closely related to the growth and development of the human body. Alzheimer's disease(AD) is one of the common neurodegenerative diseases, with the main pathological features of Aß deposition and Tau phosphorylation, which activate neurotoxic reactions and eventually lead to neuronal dysfunction and cell death, severely impairing the patient's cognitive and memory functions. Although research results have been achieved in the TCM treatment of AD, the complex pathogenesis of AD makes it difficult to develop the drugs capable of curing AD. The stem cell therapy is an important method to promote self-repair and regeneration, and bone marrow mesenchymal stem cells(BMSCs) as adult stem cells have the ability of multi-directional differentiation. By reviewing the relevant literature, this paper discusses the association between BMSCs and the TCM theory of kidney storing essence, and expounds the material basis of this theory from the perspective of molecular biology. Studies have shown that TCM with the effect of tonifying the kidney in the treatment of AD are associated with BMSCs. Exosomes produced by such cells are one of the main substances affecting AD. Exosomes containing nucleic acids, proteins, and lipids can participate in intercellular communication, regulate cell function, and affect AD by reducing Aß deposition, inhibiting Tau protein phosphorylation and neuroinflammation, and promoting neuronal regeneration. Therefore, discussing the prevention and treatment of exosomes and AD based on the theory of kidney storing essence will provide a new research idea for the TCM treatment of AD.
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Doença de Alzheimer , Exossomos , Adulto , Humanos , Doença de Alzheimer/prevenção & controle , Doença de Alzheimer/tratamento farmacológico , Exossomos/metabolismo , Exossomos/patologia , Rim/patologia , Medicina Tradicional Chinesa , NeurôniosRESUMO
Two-dimensional (2D) rare-earth oxyhalides (REOXs) with novel properties offer fascinating opportunities for fundamental research and applications. The preparation of 2D REOX nanoflakes and heterostructures is crucial for revealing their intrinsic properties and realizing high-performance devices. However, it is still a great challenge to fabricate 2D REOX using a general approach. Herein, we design a facile strategy to prepare 2D LnOCl (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy) nanoflakes using the molten salt method assisted by the substrate. A dual-driving mechanism was proposed in which the lateral growth could be guaranteed by the quasi-layered structure of LnOCl and the interaction between the nanoflakes and the substrate. Furthermore, this strategy has also been successfully applied for block-by-block epitaxial growth of diverse lateral heterostructures and superlattice. More significantly, the high performance of MoS2 field-effect transistors with LaOCl nanoflake as the gate dielectric was demonstrated, exhibiting competitive device characteristics of high on/off ratios up to 107 and low subthreshold swings down to 77.1 mV dec-1. This work offers a deep understanding of the growth of 2D REOX and heterostructures, shedding new light on the potential applications in future electronic devices.
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Nuciferine aporphine alkaloid mainly exists in Nelumbo nucifera Gaertn and is a beneficial to human health, such as anti-obesity, lowering blood lipid, prevention of diabetes and cancer, closely associated with inflammation. Importantly, nuciferine may contribute to its bioactivities by exerting intense anti-inflammatory activities in multiple models. However, no review has summarized the anti-inflammatory effect of nuciferine. This review critically summarized the information regarding the structure-activity relationships of dietary nuciferine. Moreover, biological activities and clinical application on inflammation-related diseases, such as obesity, diabetes, liver, cardiovascular diseases, and cancer, as well as their potential mechanisms, involving oxidative stress, metabolic signaling, and gut microbiota has been reviewed. The current work provides a better understanding of the anti-inflammation properties of nuciferine against multiple diseases, thereby improving the utilization and application of nuciferine-containing plants across functional food and medicine.
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Aporfinas , Fígado , Humanos , Fígado/metabolismo , Aporfinas/farmacologia , Aporfinas/uso terapêutico , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Relação Estrutura-AtividadeRESUMO
BACKGROUND: Measles-containing vaccine (MCV) has been effective in controlling the spread of measles. Some countries have declared measles elimination. But recently years, the number of cases worldwide has increased, posing a challenge to the global goal of measles eradication. This study estimated the relationship between meteorological factors and measles using spatiotemporal Bayesian model, aiming to provide scientific evidence for public health policy to eliminate measles. METHODS: Descriptive statistical analysis was performed on monthly data of measles and meteorological variables in 136 counties of Shandong Province from 2009 to 2017. Spatiotemporal Bayesian model was used to estimate the effects of meteorological factors on measles, and to evaluate measles risk areas at county level. Case population was divided into multiple subgroups according to gender, age and occupation. The effects of meteorological factors on measles in subgroups were compared. RESULTS: Specific meteorological conditions increased the risk of measles, including lower relative humidity, temperature, and atmospheric pressure; higher wind velocity, sunshine duration, and diurnal temperature variation. Taking lowest value (Q1) as reference, RR (95%CI) for higher temperatures (Q2-Q4) were 0.79 (0.69-0.91), 0.54 (0.44-0.65), and 0.48 (0.38-0.61), respectively; RR (95%CI) for higher relative humidity (Q2-Q4) were 0.76 (0.66-0.88), 0.56 (0.47-0.67), and 0.49 (0.38-0.63), respectively; RR (95%CI) for higher wind velocity (Q2-Q4) were 1.43 (1.25-1.64), 1.85 (1.57-2.18), 2.00 (1.59-2.52), respectively. 22 medium-to-high risk counties were identified, mainly in northwestern, southwestern and central Shandong Province. The trend was basically same in the effects of meteorological factors on measles in subgroups, but the magnitude of the effects was different. CONCLUSIONS: Meteorological factors have an important impact on measles. It is crucial to integrate these factors into public health policies for measles prevention and control in China.
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Sarampo , Conceitos Meteorológicos , Humanos , Incidência , Teorema de Bayes , Temperatura , China/epidemiologia , Sarampo/epidemiologia , Sarampo/prevenção & controleRESUMO
BACKGROUND: Acrylamide (AA) is a potential carcinogen formed in food rich in carbohydrate during heating. Recently, AA has been found in several fruit products, such as prune juice, sugarcane molasses and canned black olives. This study focused on the role of galacturonic acid (GalA), the main acid hydrolysis product of fruit pectin, in AA formation in three model systems - asparagine (Asn)/glucose (Glc), Asn/GalA, and Asn/Glc/GalA - during heating under different pH values (pH 3.8-7.8), Glc concentration (0-0.1 mol L-1 ), molar ratio of substrates (Asn/Glc = 1:1, 0.025-0.5 mol L-1 ) and temperature (120-180 °C) for 30 min, respectively. RESULTS: The results suggested that the addition of 0.1 mol L-1 GalA strongly accelerated AA formation in a manner dependent on pH value and temperature (P < 0.05). AA concentration under different Glc concentration and molar ratio of substrates suggested that GalA was more reactive than Glc when reacted with Asn. Furthermore, the Amadori rearrangement product/Schiff base/oxazolidine-5-one were identified as the intermediates formed in the Asn/GalA model system using ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry. CONCLUSION: The results suggested that Maillard reaction between Asn and GalA might contribute to AA formation. This study is significant in elucidating the contribution of interaction between components for AA formation in fruit products. © 2022 Society of Chemical Industry.
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Acrilamida , Reação de Maillard , Acrilamida/química , Asparagina/química , Glucose/química , Aceleração , Temperatura AltaRESUMO
Particulate matter 2.5 (PM2.5) is a widely known atmospheric pollutant which can induce the aging-related pulmonary diseases such as acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD) and interstitial pulmonary fibrosis (IPF). In recent years, with the increasing atmospheric pollution, airborne fine PM2.5, which is an integral part of air pollutants, has become a thorny problem. Hence, this study focused on the effect of PM2.5 on cellular senescence in the lung, identifying which inflammatory pathway mediated PM2.5-induced cellular senescence and how to play a protective role against this issue. Our data suggested that PM2.5 induced time- and concentration-dependent increasement in the senescence of A549 cells. Using an inhibitor of cGAS (PF-06928215) and an inhibitor of NF-κB (BAY 11-7082), it was revealed that PM2.5-induced senescence was regulated by inflammatory response, which was closely related to the cGAS/STING/NF-κB pathway activated by DNA damage. Moreover, our study also showed that the pretreatment with selenomethionine (Se-Met) could inhibit inflammatory response and prevent cellular senescence by hindering cGAS/STING/NF-κB pathway in A549 cells exposed to PM2.5. Furthermore, in vivo C57BL/6J mice model demonstrated that aging of mouse lung tissue caused by PM2.5 was attenuated by decreasing cGAS expression after Se-Met treatment. Our findings indicated that selenium made a defense capability for PM2.5-induced cellular senescence in the lung, which provided a novel insight for resisting the harm of PM2.5 to human health.
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NF-kappa B , Selenometionina , Animais , Humanos , Camundongos , Antioxidantes , Senescência Celular , Pulmão , Camundongos Endogâmicos C57BL , Nucleotidiltransferases , Material Particulado/toxicidadeRESUMO
BACKGROUND: Hand-foot-mouth disease (HFMD) is a global public health issues, especially in China. It has threat the health of children under 5 years old. The early recognition of high-risk districts and understanding of epidemic characteristics can facilitate health sectors to prevent the occurrence of HFMD effectively. METHODS: Descriptive analysis was used to summarize epidemic characteristics, and the spatial autocorrelation analysis and space-time scan analysis were utilized to explore distribution pattern of HFMD and identify hot spots with statistical significance. The result was presented in ArcMap. RESULTS: A total of 52,095 HFMD cases were collected in Zibo city from 1 Jan 2010 to 31 Dec 2019. The annual average incidence was 129.72/100,000. The distribution of HFMD was a unimodal trend, with peak from April to September. The most susceptible age group was children under 5 years old (92.46%), and the male-to-female ratio is 1.60: 1. The main clusters were identified in Zhangdian District from 12 April 2010 to 18 September 2012. Spatial autocorrelation analysis showed that the global spatial correlation in Zibo were no statistical significance, except in 2012, 2014, 2015, 2016 and 2018. Cold spots were gathered in Boshan county and Linzi district, while hot spots only in Zhangdian District in 2018, but other years were no significance. CONCLUSION: Hot spots mainly concentrated in the central and surrounding city of Zibo city. We suggest that imminent public health planning and resource allocation should be focused within those areas.
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Doença de Mão, Pé e Boca , Doenças da Boca , Criança , Pré-Escolar , China/epidemiologia , Cidades , Feminino , Doença de Mão, Pé e Boca/epidemiologia , Humanos , Incidência , Lactente , Masculino , Análise Espaço-TemporalRESUMO
Tumor suppressor candidate 3 (TUSC3) is a coding gene responsible for N-glycosylation of many critical proteins. TUSC3 gene plays an oncogenic role in colorectal cancer (CRC), however, the role of TUSC3 in drug resistance of CRC is still unclear. The aim of this study is to investigate the biological function and molecular mechanism of TUSC3 in CRC drug resistance. The expression of TUSC3 in CRC is positively correlated to tumor stage in 90 paired clinical samples, and negatively associated with overall survival and disease-free survival of CRC patients. In vitro, TUSC3 promotes the formation of stemness and induces the drug resistance to 5-fluorouracil and cis-dichlorodiammineplatinum(II) in CRC cells. The tissue microarray assay and bioinformatic analysis indicate that TUSC3 may promote the expression of CD133 and ABCC1 via Hedgehog signaling pathway. Treatment of Hedgehog signaling pathway agonist or inhibitor in TUSC3-silenced or TUSC3-overexpressed cells reverse the effects of TUSC3 in cellular stemness phenotype and drug resistance. Meanwhile, coimmunoprecipitation and immunofluorescence assays indicate a tight relationship between TUSC3 and SMO protein. Our data suggest that TUSC3 promotes the formation of cellular stemness and induces drug resistance via Hedgehog signaling pathway in CRC.
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Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/patologia , Resistencia a Medicamentos Antineoplásicos , Fluoruracila/farmacologia , Regulação Neoplásica da Expressão Gênica , Proteínas de Membrana/metabolismo , Células-Tronco Neoplásicas/patologia , Proteínas Supressoras de Tumor/metabolismo , Animais , Antimetabólitos Antineoplásicos/farmacologia , Apoptose , Biomarcadores Tumorais/genética , Movimento Celular , Proliferação de Células , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Transição Epitelial-Mesenquimal , Feminino , Humanos , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/efeitos dos fármacos , Prognóstico , Taxa de Sobrevida , Células Tumorais Cultivadas , Proteínas Supressoras de Tumor/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Genome-wide association studies (GWAS) have successfully identified genetic susceptible variants for complex diseases. However, the underlying mechanism of such association remains largely unknown. Most disease-associated genetic variants have been shown to reside in noncoding regions, leading to the hypothesis that regulation of gene expression may be the primary biological mechanism. Current methods to characterize gene expression mediating the effect of genetic variant on diseases, often analyzed one gene at a time and ignored the network structure. The impact of genetic variant can propagate to other genes along the links in the network, then to the final disease. There could be multiple pathways from the genetic variant to the final disease, with each having the chain structure since the first node is one specific SNP (Single Nucleotide Polymorphism) variant and the end is disease outcome. One key but inadequately addressed question is how to measure the between-node connection strength and rank the effects of such chain-type pathways, which can provide statistical evidence to give the priority of some pathways for potential drug development in a cost-effective manner. RESULTS: We first introduce the maximal correlation coefficient (MCC) to represent the between-node connection, and then integrate MCC with K shortest paths algorithm to rank and identify the potential pathways from genetic variant to disease. The pathway importance score (PIS) was further provided to quantify the importance of each pathway. We termed this method as "MCC-SP". Various simulations are conducted to illustrate MCC is a better measurement of the between-node connection strength than other quantities including Pearson correlation, Spearman correlation, distance correlation, mutual information, and maximal information coefficient. Finally, we applied MCC-SP to analyze one real dataset from the Religious Orders Study and the Memory and Aging Project, and successfully detected 2 typical pathways from APOE genotype to Alzheimer's disease (AD) through gene expression enriched in Alzheimer's disease pathway. CONCLUSIONS: MCC-SP has powerful and robust performance in identifying the pathway(s) from the genetic variant to the disease. The source code of MCC-SP is freely available at GitHub ( https://github.com/zhuyuchen95/ADnet ).
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Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único , Algoritmos , Doença de Alzheimer/genética , Simulação por Computador , Genótipo , Humanos , Modelos Genéticos , SoftwareRESUMO
BACKGROUND: The early warning model of infectious diseases plays a key role in prevention and control. This study aims to using seasonal autoregressive fractionally integrated moving average (SARFIMA) model to predict the incidence of hemorrhagic fever with renal syndrome (HFRS) and comparing with seasonal autoregressive integrated moving average (SARIMA) model to evaluate its prediction effect. METHODS: Data on notified HFRS cases in Weifang city, Shandong Province were collected from the official website and Shandong Center for Disease Control and Prevention between January 1, 2005 and December 31, 2018. The SARFIMA model considering both the short memory and long memory was performed to fit and predict the HFRS series. Besides, we compared accuracy of fit and prediction between SARFIMA and SARIMA which was used widely in infectious diseases. RESULTS: Model assessments indicated that the SARFIMA model has better goodness of fit (SARFIMA (1, 0.11, 2)(1, 0, 1)12: Akaike information criterion (AIC):-631.31; SARIMA (1, 0, 2)(1, 1, 1)12: AIC: - 227.32) and better predictive ability than the SARIMA model (SARFIMA: root mean square error (RMSE):0.058; SARIMA: RMSE: 0.090). CONCLUSIONS: The SARFIMA model produces superior forecast performance than the SARIMA model for HFRS. Hence, the SARFIMA model may help to improve the forecast of monthly HFRS incidence based on a long-range dataset.
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Doenças Transmissíveis , Febre Hemorrágica com Síndrome Renal , Previsões , Febre Hemorrágica com Síndrome Renal/diagnóstico , Febre Hemorrágica com Síndrome Renal/epidemiologia , Humanos , Incidência , Modelos Estatísticos , Estações do AnoRESUMO
In molecular breeding of super rice, it is essential to isolate the best quantitative trait loci (QTLs) and genes of leaf shape and explore yield potential using large germplasm collections and genetic populations. In this study, a recombinant inbred line (RIL) population was used, which was derived from a cross between the following parental lines: hybrid rice Chunyou84, that is, japonica maintainer line Chunjiang16B (CJ16); and indica restorer line Chunhui 84 (C84) with remarkable leaf morphological differences. QTLs mapping of leaf shape traits was analyzed at the heading stage under different environmental conditions in Hainan (HN) and Hangzhou (HZ). A major QTL qLL9 for leaf length was detected and its function was studied using a population derived from a single residual heterozygote (RH), which was identified in the original population. qLL9 was delimitated to a 16.17 kb region flanked by molecular markers C-1640 and C-1642, which contained three open reading frames (ORFs). We found that the candidate gene for qLL9 is allelic to DEP1 using quantitative real-time polymerase chain reaction (qRT-PCR), sequence comparison, and the clustered regularly interspaced short palindromic repeat-associated Cas9 nuclease (CRISPR/Cas9) genome editing techniques. To identify the effect of qLL9 on yield, leaf shape and grain traits were measured in near isogenic lines (NILs) NIL-qLL9CJ16 and NIL-qLL9C84, as well as a chromosome segment substitution line (CSSL) CSSL-qLL9KASA with a Kasalath introgressed segment covering qLL9 in the Wuyunjing (WYJ) 7 backgrounds. Our results showed that the flag leaf lengths of NIL-qLL9C84 and CSSL-qLL9KASA were significantly different from those of NIL-qLL9CJ16 and WYJ 7, respectively. Compared with NIL-qLL9CJ16, the spike length, grain size, and thousand-grain weight of NIL-qLL9C84 were significantly higher, resulting in a significant increase in yield of 15.08%. Exploring and pyramiding beneficial genes resembling qLL9C84 for super rice breeding could increase both the source (e.g., leaf length and leaf area) and the sink (e.g., yield traits). This study provides a foundation for future investigation of the molecular mechanisms underlying the sourceâ»sink balance and high-yield potential of rice, benefiting high-yield molecular design breeding for global food security.
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Grão Comestível/genética , Oryza/genética , Folhas de Planta/genética , Locos de Características Quantitativas/genética , Alelos , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Grão Comestível/crescimento & desenvolvimento , Genótipo , Oryza/crescimento & desenvolvimento , Fenótipo , Folhas de Planta/crescimento & desenvolvimentoRESUMO
BACKGROUND: Acrylamide (AA) is a potential carcinogen which widely exists in heat-processed foods. The addition of glycine (Gly) has been shown to reduce the formation of AA. The objective of this work was to investigate the kinetics of the inhibition of AA by Gly in both asparagine (Asn)/glucose (Glc) and Asn/Glc/Gly potato model systems during heating at 160 °C, 180 °C, and 200 °C. RESULTS: The simplified two consecutive first-order kinetic model fitted well to the changes of AA in both systems. No significant difference in rate constant (kF) and apparent activation energy (EaF) was observed for AA formation between the two systems (P > 0.05). Whereas EaE and only kE at 200 °C for AA elimination in the Asn/Glc/Gly system was significantly higher than Asn/Glc system (P < 0.05). The elimination reaction between Gly and AA was confirmed by the identification of their major reaction product 2-((3-amino-3-oxopropyl)amino)acetic acid in the Asn/Glc/(15) N-Gly system. CONCLUSION: The reduction of AA by Gly is predominantly attributed to the elimination reaction between Gly and AA.
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Acrilamida/antagonistas & inibidores , Glicina/farmacologia , Solanum tuberosum/química , Acrilamida/análise , Acrilamida/química , Asparagina/análise , Asparagina/química , Carcinógenos/antagonistas & inibidores , Carcinógenos/química , Cromatografia Líquida de Alta Pressão , Glucose/análise , Glucose/química , Glicina/análise , Glicina/química , Temperatura Alta , Cinética , Espectrometria de Massas em Tandem , TermodinâmicaRESUMO
An unprecedented visible-light-induced direct C-H bond difluoroalkylation of aldehyde-derived hydrazones was developed. This reaction represents a new way to synthesize substituted hydrazones. The salient features of this reaction include difluorinated hydrazone synthesis rather than classical amine synthesis, extremely mild reaction conditions, high efficiency, wide substrate scope, ease in further transformations of the products, and one-pot syntheses. Mechanistic analyses and theoretical calculations indicate that this reaction is enabled by a novel aminyl radical/polar crossover mechanism, with the aminyl radical being oxidized into the corresponding aminyl cation through a single electron transfer (SET) process.
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Interface strain significantly affects the band structure and electronic states of metal-nanocrystal-2D-semiconductor heterostructures, impacting system performance. While transmission electron microscopy (TEM) is a powerful tool for studying interface strain, its accuracy may be compromised by sample overlap in high-resolution images due to the unique nature of the metal-nanocrystals-2D-semiconductors heterostructure. Utilizing digital dark-field technology, the substrate influence on metal atomic column contrasts is eliminated, improving the accuracy of quantitative analysis in high-resolution TEM images. Applying this method to investigate Pt on MoS2 surfaces reveals that the heterostructure introduces a tensile strain of ≈3% in Pt nanocrystal. The x-directional linear strain in Pt nanocrystals has a periodic distribution that matches the semi-coherent interface between Pt nanocrystals and MoS2, while the remaining strain components localize mainly on edge atomic steps. These results demonstrate an accurate and efficient method for studying interface strain and provide a theoretical foundation for precise heterostructure fabrication.
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BACKGROUND: The micro gas chromatography column (µGCC) is one of the key components of the miniaturized gas chromatography system. However, light alkanes are difficult to be separated by a micro gas chromatography column, especially for methane and ethane, because the length of µGCC is limited by the area of a silicon substrate. More importantly, the heterogeneous microchannel surface formed by silicon glass bonding causes uneven stationary phase coating and the forces between the untreated microchannel surfaces and the stationary phase materials are weak, which will prevent the improvement of separation performance. RESULTS: In this paper, a micro gas chromatography column (µGCC) with uniform HKUST-1 stationary phase is reported. Significantly, an alumina film prepared by the atomic layer deposition (ALD) technique is used to homogenize the heterogeneous microchannels. The alumina is a hydrophilic material and the alumina made by the ALD technique is uniform. The forces between hydrophilic alumina film and HKUST-1 are strong, which can greatly improve the coating uniformity of the hydrophilic stationary phase HKUST-1. The test results show that the µGCC could baseline separate the light alkane mixtures (CH4, C2H6, C3H8, and C4H10) at the high testing temperature of 120 °C. The maximum resolution of the difficult-separated methane and ethane reached 19.2, which is 108 % higher than the µGCC using the same stationary phase without homogenizing the microchannel inner surface. SIGNIFICANCE: The µGCC uses ALD alumina film to homogenize the microchannel inner surface; meanwhile, hydrophilic ALD alumina has a strong electrostatic attraction with the hydrophilic stationary phase HKUST-1. Homogeneous microchannel surface and strong electrostatic attraction are favorable to obtain uniform stationary phase which greatly improves the separation performance, resulting in a large resolution for methane and ethane. The µGCC has broad application prospects in light alkane separation.
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Acrylamide (AA) is a neoformed compound in heated foods, mainly produced between asparagine (Asn) and glucose (Glc) during the Maillard reaction. Galacturonic acid (GalA), the major component of pectin, exhibits high activity in AA formation. This study investigated the pathway for AA formation between GalA and Asn. Three possible pathways were proposed: 1) The carbonyl group of GalA directly interacts with Asn to produce AA; 2) GalA undergoes an oxidative cleavage reaction to release α-dicarbonyl compounds, which subsequently leads to AA production; 3) 5-formyl-2-furancarboxylic acid, the thermal degradation product of GalA, reacts with Asn to generate AA. Structural analysis revealed that the COOH group in GalA accelerated intramolecular protonation and electron transfer processes, thereby increasing the formation of AA precursors such as decarboxylated Schiff base and α-dicarbonyl compounds, promoting AA formation. This study provides a theoretical basis and new insights into the formation and control of AA.
Assuntos
Acrilamida , Ácidos Hexurônicos , Acrilamida/química , Ácidos Hexurônicos/química , Reação de Maillard , Asparagina/química , Temperatura Alta , Pectinas/química , Estrutura MolecularRESUMO
Poly(glycerol monomethacrylate) (PGMA) prepared by reversible addition-fragmentation chain transfer polymerization was investigated as an additive for high-loading iron oxide nanoparticle (IOP) 3D printable inks. The effect of adjusting the molar mass and loading of PGMA on the rheology of IOP suspensions was investigated, and an optimized ink formulation containing 70% w/w IOPs and 0.25% w/w PGMA98 at pH 10 was developed. This ink was successfully 3D printed onto various substrates and into several structures, including rectangles, high aspect ratio cylinders, letters, spiral- and comb-shaped structures, and thin- and thick-walled toroids. The effect of sintering on the mechanical properties of printed artifacts was investigated via four-point flexural and compressive testing, with higher sintering temperatures resulting in improved mechanical properties due to changes in the particle size and microstructure. The printed toroids were fabricated into inductors, and their electrical performance was assessed via impedance spectroscopy at a working frequency range of 0.001-13 MHz. There was a clear trade-off between electrical properties and sintering temperature due to a phase change between γ-Fe2O3 and α-Fe2O3 upon heating. Nevertheless, the optimized devices had a Q factor of â¼40 at 10 MHz, representing a superior performance compared to that of other inductors with iron oxide cores previously reported. Thus, this report represents a significant step toward the development of low-cost, fully aqueous, high loading, and 3D printable ceramic inks for high-performance inductors and functional devices.