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1.
Int Immunopharmacol ; 137: 112432, 2024 Aug 20.
Article in English | MEDLINE | ID: mdl-38865751

ABSTRACT

BACKGROUND: Papillary thyroid cancer (PTC) is the most common type of thyroid cancer. Identification of novel biomarkers can potentially help explore the underlying molecular mechanisms of PTC. Long non-coding RNAs (lncRNAs) are involved in cancer development. However, understanding the role of lncRNA in PTC remains challenging. METHODS: Based on the competitive endogenous RNA (ceRNA) theory, we constructed a comprehensive PTC-related lncRNA-miRNA-mRNA network using data from The Cancer Genome Atlas. To evaluate the prognostic power, we performed survival analysis for patients with PTC with low and high lncRNA expression levels, and examined the relationship between lncRNA and immune-related functions. RESULTS: We identified a hub node, long intergenic non-coding RNA, LINC00657, as a novel prognostic biomarker in PTC. LINC00657 was differentially expressed between tumor and adjacent normal samples. Low LINC00657 expression levels was significantly associated with better survival outcome. Our functional analyses showed that LINC00657 was related with infiltration of CD8+ T cell and macrophage; immune check point molecules; and immune metagenes such as IgG, LCK, MHC_I/II and etc. These results suggest that LINC00657 is an immune-related biomarker with potential clinical applicability. Additionally, cancer-related signaling pathway and high frequency of gene BRAF mutation were found in PTC samples with high LINC00657 expression level, which were consistent with previous findings. CONCLUSION: LINC00657 is an immune-related biomarker that can potentially improve prognosis prediction in PTC. Our study provided new treatment target of PTC in clinical practice and offered the novel insights in elucidating the functional role of lncRNAs.


Subject(s)
Biomarkers, Tumor , Gene Expression Regulation, Neoplastic , MicroRNAs , RNA, Long Noncoding , RNA, Messenger , Thyroid Cancer, Papillary , Thyroid Neoplasms , Humans , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Thyroid Cancer, Papillary/genetics , Thyroid Cancer, Papillary/mortality , Thyroid Cancer, Papillary/immunology , Biomarkers, Tumor/genetics , Prognosis , Thyroid Neoplasms/genetics , Thyroid Neoplasms/mortality , MicroRNAs/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Gene Regulatory Networks , Male , Female
2.
Plant Reprod ; 2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38844561

ABSTRACT

KEY MESSAGE: Candidate male sterility genes were identified in sugarcane, which interacts with kinase-related proteins, transcription factors, and plant hormone signaling pathways to regulate stamen and anther development. Saccharum officinarum is a cultivated sugarcane species that its predominant feature is high sucrose content in stems. Flowering is necessary for breeding new cultivars but will terminate plant growth and reduce sugar yield. The wild sugarcane species Saccharum spontaneum has robust and viable pollen, whereas most S. officinarum accessions are male sterile, which is a desirable trait of a maternal parent in sugarcane breeding. To study male sterility and related regulatory pathways in sugarcane, we carried out RNAseq using flowers in different developmental stages between male-sterile S. officinarum accession 'LA Purple' and fertile S. spontaneum accession 'SES208'. Gene expression profiles were used to detect how genes are differentially expressed between male sterile and fertile flowers and to identify candidate genes for male sterility. Weighted gene correlation networks analysis (WGCNA) was conducted to investigate the regulatory networks. Transcriptomic analyses showed that 988 genes and 2888 alleles were differentially expressed in S. officinarum compared to S. spontaneum. Ten differentially expressed genes and thirty alleles were identified as candidate genes and alleles for male sterility in sugarcane. The gene Sspon.03G0007630 and two alleles of the gene Sspon.08G0002270, Sspon.08G0002270-2B and Sspon.08G0014700-1A, were involved in the early stamen or carpel development stages, while the remaining genes were classified into the post-meiosis stage. Gibberellin, auxin, and jasmonic acid signaling pathways are involved in the stamen development in sugarcane. The results expanded our knowledge of male sterility-related genes in sugarcane and generated genomic resources to facilitate the selection of ideal maternal parents to improve breeding efficiency.

3.
Heliyon ; 10(9): e30499, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38726156

ABSTRACT

Rapid, universal and accurate identification of chemical composition changes in multi-component traditional Chinese medicine (TCM) decoction is a necessary condition for elucidating the effectiveness and mechanism of pharmacodynamic substances in TCM. In this paper, SERS technology, combined with grating-like SERS substrate and machine learning method, was used to establish an efficient and sensitive method for the detection of TCM decoction. Firstly, the grating-like substrate prepared by magnetron sputtering technology was served as a reliable SERS sensor for the identification of TCM decoction. The enhancement factor (EF) of 4-ATP probe molecules was as high as 1.90 × 107 and the limit of detection (LOD) was as low as 1 × 10-10 M. Then, SERS technology combined with support vector machine (SVM), decision tree (DT), Naive Bayes (NB) and other machine learning algorithms were used to classify and identify the three TCM decoctions, and the classification accuracy rate was as high as 97.78 %. In summary, it is expected that the proposed method combining SERS and machine learning method will have a high development in the practical application of multi-component analytes in TCM.

4.
ChemSusChem ; : e202400552, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38622064

ABSTRACT

We represent a segmented flow surfactant-free microfluidic strategy for continuous synthesis of Prussian blue analogues (PBAs) with high dispersity and high crystallization. Representative zinc hexacyanoferrate (ZnHCF) nanocubes were successfully synthesized in a microfluidic reactor within a few minutes via the cooperation method and possessed lower contents of crystal water and Fe(CN)6 3- vacancies than that of synthesis in bulk solution. The nucleation and particle growth process can be precisely controlled by the exploration of different flow rates and reaction temperatures during the formation of ZnHCF nanocubes in segmented flow microfluidic reactors. High crystallinity, low crystal water and vacancies in the ZnHCF structure were presented at relatively high temperatures for the crystal growth process. High-quality ZnHCF with a low content of crystal water showed excellent electrochemical activity and stability towards zinc-ion storage. The continuous and scalable synthesis approach can be extended to the fabrication of other PBAs such as NiHCF, CoHCF, MnHCF, and CuHCF with high dispersity without using any surfactants. The controllable construction of PBAs with tunable properties in microfluidic reactors provides a promising direction to minimize the gap between commercial reality and laboratory research.

5.
Opt Lett ; 49(6): 1504-1507, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38489436

ABSTRACT

Mn4+-activated oxide phosphors with low cost and unique luminescent properties have been considered as a promising candidate for various optical applications, while the search for high thermal stable red-emitting phosphors is still a huge challenge. In our work, we find and unveil the relationship between luminescence thermal quenching behavior and thermal expansion coefficients (α/10-6 K-1) based on double-perovskite niobate phosphors Ca2LnNbO6:Mn4+ (Ln3+ = Y3+, Gd3+, La3+, or Lu3+). It can be concluded that the phosphors with low thermal expansion coefficients contribute to high thermal stability. Subsequently, Ca2LuNbO6:Mn4+ accomplishes accurate temperature testing and high-CRI white light-emitting diodes. Thus, a thermal expansion coefficient strategy is a new guide to select the appropriate substrate with high thermal stability for an Mn4+-activated emitter.

6.
Spectrochim Acta A Mol Biomol Spectrosc ; 310: 123967, 2024 Apr 05.
Article in English | MEDLINE | ID: mdl-38309008

ABSTRACT

The high-density particle distribution in capillary was a crucial factor for enhancing SERS properties and a difficult point in the preparation process. The direct high-temperature method was used to fuse the particles and form a uniform and dense particle distribution on the capillary's inner wall, providing a foundation for enhancing Raman signals. The prepared capillary SERS substrate strongly enhances the rhodamine 6G (R6G) signal, and the RSD values of several characteristic peaks of R6G are about 10 %, demonstrating high sensitivity, uniformity, and stability. Using capillary SERS substrate for detecting goat serum. Embedding precious metal particles into capillary SERS substrate can effectively encapsulate the tested liquid and avoid contamination, which improves the disadvantage of traditional substrates exposing the liquid to air. The prepared capillary SERS substrate could be used for field and biomedical sensitivity detection, providing a theoretical and experimental basis for developing the capillary SERS substrate.

7.
Opt Lett ; 49(4): 1089-1092, 2024 Feb 15.
Article in English | MEDLINE | ID: mdl-38359260

ABSTRACT

A focusing nanostructure with tailored polarization properties based on a metal-dielectric slab waveguide combined with plasmonic slits and gratings is proposed. The polarization state of the focus light can be controlled with overlapping a transverse magnetic (TM) focus and a transverse electric (TE) focus, which are formed by focusing the waveguide modes into free space via grating coupling, extraordinary transmission, and plasmonic beaming. We demonstrated that it is possible to achieve either multiple foci or a single focal spot of the transmitted light with tailored polarization states by judicious design of the structure parameter and the polarization state of the incident light.

8.
Angew Chem Int Ed Engl ; 63(19): e202402274, 2024 May 06.
Article in English | MEDLINE | ID: mdl-38415322

ABSTRACT

The high theoretical energy density (1274 Wh kg-1) and high safety enable the all-solid-state Na-S batteries with great promise for stationary energy storage system. However, the uncontrollable solid-liquid-solid multiphase conversion and its associated sluggish polysulfides redox kinetics pose a great challenge in tunning the sulfur speciation pathway for practical Na-S electrochemistry. Herein, we propose a new design methodology for matrix featuring separated bi-catalytic sites that control the multi-step polysulfide transformation in tandem and direct quasi-solid reversible sulfur conversion during battery cycling. It is revealed that the N, P heteroatom hotspots are more favorable for catalyzing the long-chain polysulfides reduction, while PtNi nanocrystals manipulate the direct and full Na2S4 to Na2S low-kinetic conversion during discharging. The electrodeposited Na2S on strongly coupled PtNi and N, P-codoped carbon host is extremely electroreactive and can be readily recovered back to S8 without passivation of active species during battery recharging, which delivers a true tandem electrocatalytic quasi-solid sulfur conversion mechanism. Accordingly, stable cycling of the all-solid-state soft-package Na-S pouch cells with an attractive specific capacity of 876 mAh gS -1 and a high energy of 608 Wh kgcathode -1 (172 Wh kg-1, based on the total mass of cathode and anode) at 60 °C are demonstrated.

9.
Small ; 20(12): e2307021, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37940629

ABSTRACT

Electrochemically reversible conversion of I2/I- redox couple in a controllable iodine speciation manner is the eternal target for practical metal-iodine batteries. This contribution demonstrates an advanced polyiodide-free Zn-I2 battery achieved by the bidirectional confined redox catalysis-directed quasi-solid iodine conversion. A core-shell structured iodine cathode is fabricated by integrating multiporous Prussian blue nanocubes as a catalytic mediator, and the polypyrrole sheath afforded a confinement environment that favored the iodine redox. The zincate Znx+1FeIII/II[Fe(CN)6]y has substantially faster zinc-ion intercalation kinetics and overlapping kinetic voltage profiles compared with the I2/ZnI2 redox, and behave as a redox mediator that catalyze reduction of polyiodides via chemical redox reactions during battery discharging and an exemplary reaction is Zn(I3)2+2Znx+1FeII[Fe(CN)6]y=3ZnI2+2ZnxFeIII[Fe(CN)6]y,ΔG=-19.3 kJ mol-1). During the following recharging process, the electrodeposited ZnI2 can be facially activated by iron redox hotspots, and the ZnxFe[FeIII/II(CN)6]y served as a cation-transfer mediator and spontaneously catalyze polyiodides oxidation (Zn(I3)2+2ZnxFe[FeIII(CN)6]y=3I2+2Znx+1Fe[FeII(CN)6]y,ΔG = -7.72 kJ mol-1), manipulating the reversible one-step conversion of ZnI2 back to I2. Accordingly, a flexible solid-state battery employing the designed cathode can deliver an energy density of 215 Wh kgiodine -1.

10.
Angew Chem Int Ed Engl ; 63(6): e202317776, 2024 Feb 05.
Article in English | MEDLINE | ID: mdl-38117014

ABSTRACT

The broader implementation of current all-solid-state Na-S batteries is still plagued by high operation temperature and inefficient sulfur utilization. And the uncontrollable sulfur speciation pathway along with the sluggish polysulfide redox kinetics further compromise the theoretical potentials of Na-S chemistry. Herein, we report a confined bidirectional tandem electrocatalysis effect to tune polysulfide electrochemistry in a novel low-temperature (80 °C) all-solid-state Na-S battery that utilizes Na3 Zr2 Si2 PO12 ceramic membrane as a platform. The bifunctional hollow sulfur matrix consisting binary atomically dispersed MnN4 and CoN4 hotspots was fabricated using a sacrificial template process. Upon discharge, CoN4 sites activate sulfur species and catalyze long-chain to short-chain polysulfides reduction, while MnN4 centers substantially accelerate the low-kinetic Na2 S4 to Na2 S directly conversion, manipulating the uniform deposition of electroactive Na2 S and avoiding the formation of irreversible products (e.g., Na2 S2 ). The intrinsic synergy of two catalytic centers benefits the Na2 S decomposition and minimizes its activation barrier during battery recharging and then efficiently mitigate the cathodic passivation. As a result, the stable cycling of all-solid-state Na-S cell delivers an attractive reversible capacity of 1060 mAh g-1 with a high CE of 98.5 % and a high energy of 1008 Wh kgcathode -1 , comparable to the liquid electrolyte cells.

11.
Global Surg Educ ; 2(1): 59, 2023.
Article in English | MEDLINE | ID: mdl-38013862

ABSTRACT

Virtual education is an evolving field within the realm of surgical training. Since the onset of the COVID-19 pandemic, the application of virtual technologies in surgical education has undergone significant exploration and advancement. While originally developed to supplement in-person curricula for the development of clinical decision-making, virtual surgical education has expanded into the realms of clinical decision-making, surgical, and non-surgical skills acquisition. This manuscript aims to discuss the various applications of virtual surgical education as well as the advantages and disadvantages associated with each education modality, while offering recommendations on best practices and future directions.

12.
Chem Sci ; 14(44): 12730-12738, 2023 Nov 15.
Article in English | MEDLINE | ID: mdl-38020388

ABSTRACT

Catalyzing conversion is a promising approach to unlock the theoretical potentials of the I2/I- redox couple in aqueous Fe-I2 electrochemistry. However, most reported results only obtain one-directional efficient iodine conversion and cannot realize a balance of full reduction and reoxidation, thereby resulting in rapid capacity decay and/or low coulombic efficiency. Herein, the concept of bidirectional catalysis based on a core-shell structured composite cathode design, which accelerates the formation and the decomposition of FeI2 simultaneously during battery dynamic cycling, is proposed to regulate the Fe-I2 electrochemical reactions. Notably, the functional matrix integrates N, P co-doping and FeP nanocrystals into a carbon shell to achieve bidirectional catalysis. More specifically, the carbon shell acts as a physical barrier to effectively capture active species within its confined environment, N, P heteroatoms function better in directing the iodine reduction and FeP facilitates the decomposition of FeI2. As confirmed with in situ and ex situ analysis, the Fe-I2 cell operates a one-step but reversible I2/FeI2 pair with enhanced kinetics. Consequently, the composite cathode exhibits a reversible Fe2+ storage capability of 202 mA h g-1 with a capacity fading rate of 0.016% per cycle over 500 cycles. Further, a stable pouch cell was fabricated and yielded an energy density of 146 W h kgiodine-1. Moreover, postmortem analysis reveals that the capacity decay of the Fe-I2 cell originates from anodic degradation rather than the accumulation of inactive iodine. This study represents a promising direction to manipulate iodine redox in rechargeable metal-iodine batteries.

13.
Amino Acids ; 55(11): 1545-1555, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37726575

ABSTRACT

Amino acid metabolic profile, particularly its association with clinical characteristics, remains unclear in patients with human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) combined with metabolic disorders. In this study, we performed targeted metabolomic analyses on 64 patients with HIV/AIDS and 21 healthy controls. Twenty-four amino acids and selected intermediate metabolites in the serum were quantitatively detected using high-performance liquid chromatography-tandem mass spectrometry, and characteristic changes and metabolic pathways were analyzed in HIV-infected patients with different degrees of abnormal glucose and lipid metabolism. Spearman's partial correlation was used to analyze the association between amino acids, biochemical parameters, and inflammatory cytokines. The results showed that the main metabolic pathways of the eighteen differential metabolites involved were arginine biosynthesis and metabolism, methionine cycle, and tryptophan metabolism. Fourteen differential amino acid metabolites were positively correlated with nine inflammatory cytokines, including TNF-α, C-reactive protein, IL-1ß, and galectin-3 (FDR < 0.1). Kynurenine, ornithine, and homocysteine were positively correlated with fasting blood glucose and insulin resistance index (FDR < 0.1). Our study revealed a multi-pathway imbalance in amino acid metabolism in patients with HIV/AIDS, which was significantly correlated with inflammation and insulin resistance.


Subject(s)
Acquired Immunodeficiency Syndrome , HIV Infections , Insulin Resistance , Humans , Inflammation/metabolism , Amino Acids/metabolism , Metabolomics , Cytokines
14.
Cell ; 186(17): 3726-3743.e24, 2023 08 17.
Article in English | MEDLINE | ID: mdl-37442136

ABSTRACT

Elucidating the cellular organization of the cerebral cortex is critical for understanding brain structure and function. Using large-scale single-nucleus RNA sequencing and spatial transcriptomic analysis of 143 macaque cortical regions, we obtained a comprehensive atlas of 264 transcriptome-defined cortical cell types and mapped their spatial distribution across the entire cortex. We characterized the cortical layer and region preferences of glutamatergic, GABAergic, and non-neuronal cell types, as well as regional differences in cell-type composition and neighborhood complexity. Notably, we discovered a relationship between the regional distribution of various cell types and the region's hierarchical level in the visual and somatosensory systems. Cross-species comparison of transcriptomic data from human, macaque, and mouse cortices further revealed primate-specific cell types that are enriched in layer 4, with their marker genes expressed in a region-dependent manner. Our data provide a cellular and molecular basis for understanding the evolution, development, aging, and pathogenesis of the primate brain.


Subject(s)
Cerebral Cortex , Macaca , Single-Cell Analysis , Transcriptome , Animals , Humans , Mice , Cerebral Cortex/cytology , Cerebral Cortex/metabolism , Macaca/metabolism , Transcriptome/genetics
15.
Front Immunol ; 14: 1196970, 2023.
Article in English | MEDLINE | ID: mdl-37520520

ABSTRACT

The PD-1/PD-L1 signaling pathway plays a crucial role in cancer immune evasion, and the use of anti-PD-1/PD-L1 antibodies represents a significant milestone in cancer immunotherapy. However, the low response rate observed in unselected patients and the development of therapeutic resistance remain major obstacles to their clinical application. Accumulating studies showed that overexpressed TGF-ß is another immunosuppressive factor apart from traditional immune checkpoints. Actually, the effects of PD-1 and TGF-ß pathways are independent and interactive, which work together contributing to the immune evasion of cancer cell. It has been verified that blocking TGF-ß and PD-L1 simultaneously could enhance the efficacy of PD-L1 monoclonal antibody and overcome its treatment resistance. Based on the bispecific antibody or fusion protein technology, multiple bispecific and bifunctional antibodies have been developed. In the preclinical and clinical studies, these updated antibodies exhibited potent anti-tumor activity, superior to anti-PD-1/PD-L1 monotherapies. In the review, we summarized the advances of bispecific antibodies targeting TGF-ß and PD-L1 in cancer immunotherapy. We believe these next-generation immune checkpoint inhibitors would substantially alter the cancer treatment paradigm, especially in anti-PD-1/PD-L1-resistant patients.


Subject(s)
Antibodies, Bispecific , Neoplasms , Humans , Antibodies, Bispecific/immunology , Antibodies, Bispecific/pharmacology , Antibodies, Bispecific/therapeutic use , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/pharmacology , Antibodies, Monoclonal/therapeutic use , B7-H1 Antigen/antagonists & inhibitors , B7-H1 Antigen/immunology , B7-H1 Antigen/metabolism , Immunotherapy , Transforming Growth Factor beta/antagonists & inhibitors , Transforming Growth Factor beta/immunology
16.
RSC Adv ; 13(18): 12483-12494, 2023 Apr 17.
Article in English | MEDLINE | ID: mdl-37091603

ABSTRACT

In the present work, palygorskite (PAL) supported Co-Fe oxides (CoFe@PAL) were prepared and used as a peroxymonosulfate (PMS) activator for removal of rhodamine B (RhB) in water. The results showed that CoFe@PAL prepared at impregnation solution of 50 g L-1 and calcination temperature of 500 °C showed the best catalytic performance. The removal efficiency of RhB (10 mg L-1) by PMS (0.1 mmol L-1) activated with CoFe@PAL (1 g L-1) was above 98% within 60 min. The effects of various environmental factors including initial pH, humic acid (HA) and inorganic anions on the removal effect were simultaneously investigated. The radical quenching experiments and EPR characterization revealed that ˙OH, SO4˙-, O2˙- and 1O2 radicals existed in the CoFe@PAL/PMS system simultaneously. The intermediates during RhB degradation were analyzed by LC-MS and possible degradation pathways of RhB were proposed. Moreover, CoFe@PAL exhibited superior stability and reusability.

17.
Head Neck ; 45(5): 1206-1214, 2023 05.
Article in English | MEDLINE | ID: mdl-36856344

ABSTRACT

BACKGROUND: Most nasopharyngeal carcinoma (NPC) protocols define primary gross tumor volume (GTVnx) plus a range from 2 to 5 mm as the high-dose clinical target volume (hd-CTV). However, in China, hd-CTV is defined as GTVnx plus 0 mm. METHODS: A total of 40 patients with newly diagnosed nonmetastatic NPC (T1-T4 ten cases each) treated with IMRT were consecutively enrolled. Real and virtual treatment plans were designed according to the definitions of hd-CTV recommended by China and Radiation Therapy Oncology Group (RTOG), respectively. RESULTS: The hd-CTV in China was significantly smaller than that of RTOG. Exposure doses to 5 mm subclinical involvement and OARs as well as NTCP in the China treatment plan were significantly lower than those of RTOG. CONCLUSION: It could be recommended to divide the hd-CTV into GTV and subclinical target volume and to prescribe different doses for the GTV and subclinical involvement in the IMRT plan of NPC.


Subject(s)
Nasopharyngeal Neoplasms , Radiotherapy, Intensity-Modulated , Humans , Nasopharyngeal Carcinoma , Radiotherapy, Intensity-Modulated/methods , Nasopharyngeal Neoplasms/pathology , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy Dosage , Tumor Burden
18.
World J Clin Cases ; 11(9): 2074-2083, 2023 Mar 26.
Article in English | MEDLINE | ID: mdl-36998945

ABSTRACT

BACKGROUND: Infarction of the conus medullaris is a rare form of spinal cord infarction. The first symptom is usually acute non-characteristic lumbar pain, followed by lower limb pain, saddle numbness, fecal incontinence, and sexual dysfunction. Spontaneous conus infarction with "snake-eye appearance" on magnetic resonance imaging has rarely been reported. CASE SUMMARY: We report a 79-year-old male patient with spontaneous conus infarction who had acute lower extremity pain and dysuria as the first symptoms. He did not have any recent history of aortic surgery and trauma. Magnetic resonance imaging revealed a rare "snake-eye appearance." In addition, we reviewed the literature on 23 similar cases and summarized the clinical features and magnetic resonance manifestations of common diseases related to the "snake-eye sign" to explore the etiology, imaging findings, and prognosis of spontaneous conus infarction. CONCLUSION: We conclude that acute onset of conus medullaris syndrome combined with "snake-eye appearance" should be strongly suspected as conus medullaris infarction caused by anterior spinal artery ischemia. This special imaging manifestation is helpful in the early diagnosis and treatment of conus infarction.

19.
Food Sci Nutr ; 11(2): 1013-1023, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36789073

ABSTRACT

In this study, dry-cured Spanish mackerel (Scomberomorus niphonius, DCSM) was prepared via three different methods (hot-air drying, cold-air drying, and sun drying). The content of 4-hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE) derived from lipid oxidation in whole processes was investigated by HPLC-MS/MS. The changes in fatty acid composition were detected by GC-MS, and the degree of lipid oxidation was evaluated by the levels of acid values (AV), peroxide values (POV), and thiobarbituric acid-reactive substances (TBARS). The results showed that the drying process significantly accelerated lipid oxidation in DCSM. The contents of HHE and HNE were significantly increased after processing. The content of HHE was higher by 18.44-, 13.45-, and 16.32-folds compared with that of HNE after three different processes, respectively. The HHE and HNE contents fluctuated upward during the hot-air and cold-air drying process. However, the contents of HHE and HNE increased time-dependent during the sun drying process, with the highest values of 86.33 ± 10.54 and 5.29 ± 0.54 mg/kg fish among the three different processes. Besides, there was a significant positive correlation between HHE contents and n-3 fatty acids content in hot-air drying and sun drying processes (Pearson's r = .991/.996), and HNE occurrence was closely related to n-6 fatty acid content in sun drying process (Pearson's r = .989). Regression analysis indicated that the content of HHE and TOTOXTBA values in DCSM showed good linear relationships (R 2 value = .907), which suggested that the content of HHE could be used to estimate the oxidative deterioration of dry-cured fish products.

20.
Spectrochim Acta A Mol Biomol Spectrosc ; 293: 122475, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36780743

ABSTRACT

Recently, the dual-fluorescent phenomena of excited state intramolecular thiol proton transfer (ESIPT) for 3-thiolflavone derivative (3NTF) were reported by Chou and coworkers for the first time [J. Am. Chem. Soc. 143 (2021) 12715-12724], which opened a new chapter in the field of ESIPT. Based on density functional theory (DFT) and time-dependent density functional theory (TDDFT), the proton transfer processes of 3NTF in toluene, dichloromethane and acetonitrile were studied. By optimizing the structure of the ground (S0) state and first excited (S1) state of 3NTF in different solvents, the hydrogen-bond parameters and proton-transfer potential energy curves were calculated. It was shown that although photo-excitation enhanced the intramolecular hydrogen bonding strength and thus promoted the occurrence of ESIPT, the solvent polarities inhibited the enhancement of the hydrogen bond of S1 state, which was not conducive to ESIPT. The electron spectra analyses were consistent with experimental data, which confirmed the rationality of molecular configurations. The time-evolved excited state dynamics simulation was performed based on the optimized structure of 3NTF, indicating that the ESIPT was an ultrafast photochemical reaction less than 180 fs. Moreover, we compared the potential energy surfaces of ESIPT, electronic structures based on natural transition orbitals (NTOs) method and electron-hole isosurfaces for the 3NTF and the traditional flavone molecule (3NHF), concluded that the unusually large Stokes shift fluorescence of 3NTF was mainly caused by the coupling of ESIPT and twisting intramolecular charge transfer (TICT), and the 3NTF isomer had the more nπ* character in the electron transition process. The nπ* ICT significantly increased with the decrease of solvent polarities, affecting the molecular photophysical properties, this made it more widely used in biomedical, photochemical, materials science and other fields.

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