Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 38
Filter
1.
Aging Dis ; 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-39012671

ABSTRACT

Fatigue, commonly experienced in daily life, is a feeling of extreme tiredness, shortage or lack of energy, exhaustion, and difficulty in performing voluntary tasks. Central fatigue, defined as a progressive failure to voluntarily activate the muscle, is typically linked to moderate- or light-intensity exercise. However, in some instances, high-intensity exercise can also trigger the onset of central fatigue. Exercise-induced central fatigue often precedes the decline in physical performance in well-trained athletes. This leads to a reduction in nerve impulses, decreased neuronal excitability, and an imbalance in brain homeostasis, all of which can adversely impact an athlete's performance and the longevity of their sports career. Therefore, implementing strategies to delay the onset of exercise-induced central fatigue is vital for enhancing athletic performance and safeguarding athletes from the debilitating effects of fatigue. In this review, we discuss the structural basis, measurement methods, and biomarkers of exercise-induced central fatigue. Furthermore, we propose non-pharmacological interventions to mitigate its effects, which can potentially foster improvements in athletes' performances in a healthful and sustainable manner.

2.
J Clin Med ; 13(13)2024 Jun 22.
Article in English | MEDLINE | ID: mdl-38999217

ABSTRACT

Background/Objectives: Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated disorder presenting as mass-like lesions with obstructions. An elevated serum IgG4 level is identified in more than half of affected patients and is considered a diagnostic criterion. IgG4-RD is still easily misdiagnosed as neoplastic or infectious disease. We aimed to conduct a hospital-based study to illuminate the association between serum IgG4 levels and pancreatobiliary disorders and cancer. Methods: In this study, serum IgG4 levels were assessed at our hospital's immunology laboratory, utilizing data from the hospital's computer center, and the diagnostic codes used were based on ICD-9-CM. We analyzed IgG4 level data collected between April 2013 and April 2020, including patients' age, gender, and diseases, but excluding the rationale for IgG4 level assessment. Employing propensity score matching (PSM) at a 1:1 ratio to mitigate age and gender confounding, we analyzed 759 patients divided into groups by IgG4 levels (≤140 and >140 mg/dL; and ≤140, 141-280, >280 mg/dL). We explored associations between IgG4 levels and conditions such as pancreatobiliary cancer (the group included cholangiocarcinoma, pancreatic cancer, and ampullary cancer), cholangitis, cholangiocarcinoma, pancreatitis, pancreatic cancer, and ampullary cancer. Results: Our study analyzed the demographics, characteristics, and serum IgG4 levels of participants and found no significant differences in serum IgG4 levels across various pancreatobiliary conditions. Nevertheless, the crude odds ratios (ORs) suggested a nuanced association between a higher IgG4 level > 280 mg/dL and increased risks of cancer and pancreatitis, with crude ORs of 1.52 (p = 0.03) and 1.49 (p = 0.008), respectively. After PSM matching, the further analysis of 759 matched patients showed no significant differences in IgG4 levels > 140 mg/dL between cancerous and non-cancerous groups, nor across other pancreatobiliary conditions. A higher serum IgG4 level > 280 mg/dL was significantly associated with pancreatobiliary cancer and cholangiocarcinoma, with crude ORs of 1.61 (p = 0.026) and 1.62 (p = 0.044), respectively. In addition, IgG4 > 280 mg/dL showed a greater association with pancreatic cancer compared with 141-280 mg/dL, with crude OR of 2.18 (p = 0.038). Conclusions: Our study did not find a clear association between serum IgG4 levels (>140 mg/dL) and pancreatobiliary cancer. We observed that higher IgG4 levels (>280 mg/dL) may be associated with cholangiocarcinoma and pancreatic cancer, as indicated by crude ORs. However, the adjusted analysis did not demonstrate the significant association between IgG4 level > 280 mg/dL and cancer. Considering IgG4-RD as a chronic and persistent inflammatory status, it is more closely associated with inflammatory diseases than with cancer. Therefore, further long-term cohort studies are necessary to evaluate the potential role of IgG4 levels in cancer risk among these patients.

3.
J Formos Med Assoc ; 2024 Jun 16.
Article in English | MEDLINE | ID: mdl-38880710

ABSTRACT

BACKGROUND PURPOSE: Capsule endoscopy (CE) is a noninvasive examination for excellent visualization of small bowel mucosal lesions. We aimed to evaluate the clinical efficacy and safety of CE in pediatric patients. METHODS: From April 2014 to December 2022, CE procedures performed in children younger than 18 years of age at Taichung Veteran General Hospital were analyzed retrospectively. RESULTS: Among 136 procedures, the completion rate was 95.6% (n = 130), with a median age of 14 years old. Suspicion or evaluation of inflammatory bowel diseases (IBD) (41%) was the most common indication for CE. Other common indications of CE were chronic unexplained abdominal pain (35%) and obscure gastrointestinal bleeding or iron deficiency anemia (21%). No procedure-related complications occurred. The diagnosis of those patients with incomplete study were CD with small bowel stricture, graft-versus-host disease and duodenal ulcers. A total of 86 CE procedures showed positive findings, and the overall diagnostic yield rate was 63.2%. Small bowel ulcers (65.12%) were the most common findings. Overall, 26.5% of CE examinations resulted in a new diagnosis and 44.9% of CE exams led to a change in therapy. For patients with IBD, CE findings resulted in an even higher therapeutic change rate of 48.1%. CONCLUSIONS: CE is a safe and feasible diagnostic method to study the small intestine in children, especially for IBD. Incomplete study could be an indicator of positive finding and can potentially be a guide to identify the site of possible strictures.

4.
Plant Biotechnol J ; 2024 May 12.
Article in English | MEDLINE | ID: mdl-38735054

ABSTRACT

The reduction in crop yield caused by pathogens and pests presents a significant challenge to global food security. Genetic engineering, which aims to bolster plant defence mechanisms, emerges as a cost-effective solution for disease control. However, this approach often incurs a growth penalty, known as the growth-defence trade-off. The precise molecular mechanisms governing this phenomenon are still not completely understood, but they generally fall under two main hypotheses: a "passive" redistribution of metabolic resources, or an "active" regulatory choice to optimize plant fitness. Despite the knowledge gaps, considerable practical endeavours are in the process of disentangling growth from defence. The plant microbiome, encompassing both above- and below-ground components, plays a pivotal role in fostering plant growth and resilience to stresses. There is increasing evidence which indicates that plants maintain intimate associations with diverse, specifically selected microbial communities. Meta-analyses have unveiled well-coordinated, two-way communications between plant shoots and roots, showcasing the capacity of plants to actively manage their microbiota for balancing growth with immunity, especially in response to pathogen incursions. This review centers on successes in making use of specific root-associated microbes to mitigate the growth-defence trade-off, emphasizing pivotal advancements in unravelling the mechanisms behind plant growth and defence. These findings illuminate promising avenues for future research and practical applications.

5.
Front Bioeng Biotechnol ; 11: 1271140, 2023.
Article in English | MEDLINE | ID: mdl-37711454

ABSTRACT

Desired orthopedic implant materials must have a good biological activity and possess appropriate mechanical property that correspond to those of human bone. Although polyetheretherketone (PEEK) has displayed a promising application prospect in musculoskeletal and dentistry reconstruction thanks to its non-biodegradability and good biocompatibility in the body, the poor osseointegration and insufficient mechanical strength have significantly limited its application in the repair of load-bearing bones and surgical operations. In this study, carbon nanotubes (CNT)/calcium silicate (CS)/polyetheretherketone ternary composites were fabricated for the first time. The addition of CS was mainly aimed at improving biological activities and surface hydrophilicity, but it inevitably compromised the mechanical strength of PEEK. CNT can reinforce the composites even when brittle CS was introduced and further upgraded the biocompatibility of PEEK. The CNT/CS/PEEK composites exhibited higher mechanical strengths in tensile and bending tests, 64% and 90% higher than those of brittle CS/PEEK binary composites. Besides, after incorporation of CNT and CS into PEEK, the hydrophilicity, surface roughness and ability to induce apatite-layer deposition were significantly enhanced. More importantly, the adhesion, proliferation, and osteogenic differentiation of mouse embryo osteoblasts were effectively promoted on CNT/CS/PEEK composites. In contrast to PEEK, these composites exhibited a more satisfactory biocompatibility and osteoinductive activity. Overall, these results demonstrate that ternary CNT/CS/PEEK composites have the potential to serve as a feasible substitute to conventional metal alloys in musculoskeletal regeneration and orthopedic implantation.

6.
J Hum Nutr Diet ; 36(5): 1649-1660, 2023 10.
Article in English | MEDLINE | ID: mdl-37485801

ABSTRACT

BACKGROUND: Crohn's disease (CD) is a progressive inflammatory disease of the gastrointestinal tract associated with malnutrition, high levels of inflammation and calcium and magnesium deficiencies. However, the relationships between these symptoms are poorly defined. METHOD: Seventy-six adult CD patients who had not yet started treatment and 83 healthy volunteers were recruited. The dietary intakes, serum calcium and magnesium levels, nutritional indicators and biochemical markers of disease activity were measured. RESULTS: Most participants had inadequate magnesium and calcium intake. The serum magnesium and calcium levels, as well as nutritional and inflammatory indicators, differed significantly between CD patients and controls, especially in the active phase. Serum levels of magnesium and calcium correlated with both nutritional status and inflammation. The cut-off values for CD development were 0.835 mmol/L (magnesium) and 2.315 mmol/L (calcium), whereas those for the active phase were 0.785 and 2.28 mmol/L, respectively. CONCLUSION: Adequate intake of magnesium and calcium may both improve the nutritional status of CD patients and reduce inflammation, benefiting disease relief. As both magnesium and calcium reflect CD status, they may be useful markers for CD diagnosis and disease activity.


Subject(s)
Crohn Disease , Adult , Humans , Crohn Disease/diagnosis , Calcium , Magnesium , Nutritional Status , Calcium, Dietary , Inflammation
7.
Cell Rep ; 42(7): 112723, 2023 07 25.
Article in English | MEDLINE | ID: mdl-37384531

ABSTRACT

RNA granules are membraneless condensates that provide functional compartmentalization within cells. The mechanisms by which RNA granules form are under intense investigation. Here, we characterize the role of mRNAs and proteins in the formation of germ granules in Drosophila. Super-resolution microscopy reveals that the number, size, and distribution of germ granules is precisely controlled. Surprisingly, germ granule mRNAs are not required for the nucleation or the persistence of germ granules but instead control their size and composition. Using an RNAi screen, we determine that RNA regulators, helicases, and mitochondrial proteins regulate germ granule number and size, while the proteins of the endoplasmic reticulum, nuclear pore complex, and cytoskeleton control their distribution. Therefore, the protein-driven formation of Drosophila germ granules is mechanistically distinct from the RNA-dependent condensation observed for other RNA granules such as stress granules and P-bodies.


Subject(s)
Drosophila Proteins , Drosophila , Animals , Cytoplasmic Granules/metabolism , Drosophila/genetics , Drosophila/metabolism , Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Germ Cell Ribonucleoprotein Granules , Germ Cells/metabolism , RNA/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism
9.
BMJ Open ; 12(8): e060361, 2022 08 24.
Article in English | MEDLINE | ID: mdl-36002209

ABSTRACT

OBJECTIVES: To evaluate the impact of Helicobacter pylori eradication on venous thromboembolism (VTE) events, and the differences between early and late treatment timing. DESIGN: A population-based cohort study. SETTING: Taiwan's National Health Insurance Research Database. PARTICIPANTS: A total of 6736 patients who received H. pylori eradication therapy from 2000 to 2010 were identified. We randomly selected 26 944 subjects matching in gender, age and baseline year as comparison cohort. PRIMARY AND SECONDARY OUTCOME MEASURES: The incidence rate ratios of VTE in the H. pylori eradication cohorts to that of the control cohort were examined. Multivariable Cox proportional hazard regression analysis was used to estimate the relative HRs and 95% CI of VTE development. RESULTS: The total incidence rate of VTE was observed in the late H. pylori eradication cohort, the early H. pylori eradication cohort and the control cohort (15.2, 3.04 and 2.91 per 1000 person-years, respectively). An age-specific trend was found in the late H. pylori eradication cohort, with a greater rate of VTE in the 50-65 years and more than 65 years age groups (adjusted HR 5.44; 95% CI 4.21 to 7.03 and 3.13; 95% CI 2.46 to 3.99). With comorbidities, the late H. pylori eradication cohort seemed to have the highest VTE incidence rate and adjusted HR (4.48, 95% CI 3.78 to 5.30). CONCLUSIONS: Late H. pylori eradication was associated with a significantly increased risk of VTE, and there was a significantly greater risk of VTE in patients with female gender, age more than 50 years and with comorbidities.


Subject(s)
Helicobacter Infections , Helicobacter pylori , Peptic Ulcer , Venous Thromboembolism , Anti-Bacterial Agents/therapeutic use , Cohort Studies , Female , Helicobacter Infections/complications , Helicobacter Infections/drug therapy , Helicobacter Infections/epidemiology , Humans , Male , Middle Aged , Peptic Ulcer/epidemiology , Venous Thromboembolism/chemically induced
10.
Neuropsychiatr Dis Treat ; 18: 1315-1328, 2022.
Article in English | MEDLINE | ID: mdl-35799798

ABSTRACT

Purpose: By exploring the gut-related microbiota differences of adolescents with non-suicidal self-injury (NSSI) and depression (without NSSI) and healthy volunteers, we provide a theoretical basis for the prevention and control of NSSI in adolescents through intestinal microecological regulation. Patients and Methods: A total of 99 subjects were recruited in Guangdong Province, China, including 51 adolescents with NSSI (KD), 24 healthy adolescents (NOR1), and 24 depression adolescents without NSSI (NOR2). General clinical data and fecal samples were collected from all subjects, who were assessed using the NSSI Behavioral Questionnaire and the 24-item Hamilton Depression Scale. The taxonomic composition of the gut microbiota was determined using the 16S rDNA gene sequencing method. Results: There were significant differences in diversity between the KD and NOR1, and the species uniformity index of the KD according to the Shannon and Simpson indices was significantly reduced compared with that of the NOR1 (4.81 vs 5.21, p<0.01; 0.02 vs 0.01, p<0.05). The relative abundances were different among the KD, NOR1 and NOR2, as reflected at the taxonomic levels of class, order, family, genus, and species. Bacteroides were the dominant flora of the KD and NOR2, while Mitsuokella was the dominant flora that distinguished the KD from the NOR2. Conclusion: We found that gut microbiota diversity was decreased in adolescents with NSSI, and the relative abundance was altered at different taxonomic levels. These results enrich the understanding of the relationship between NSSI and depression and the gut microbiota, Supporting that NSSI and depression are not homologous disorders. What is more, it establishes the basis for exploring the mechanisms of flora action in NSSI, providing a possible direction for NSSI to achieve a better prognosis and prevent relapse.

11.
Natl Sci Rev ; 9(6): nwac041, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35677225

ABSTRACT

Multi-metallic nanoparticles have been proven to be an efficient photothermal conversion material, for which the optical absorption can be broadened through the interband transitions (IBTs), but it remains a challenge due to the strong immiscibility among the repelling combinations. Here, assisted by an extremely high evaporation temperature, ultra-fast cooling and vapor-pressure strategy, the arc-discharged plasma method was employed to synthesize ultra-mixed multi-metallic nanoparticles composed of 21 elements (FeCoNiCrYTiVCuAlNbMoTaWZnCdPbBiAgInMnSn), in which the strongly repelling combinations were uniformly distributed. Due to the reinforced lattice distortion effect and excellent IBTs, the nanoparticles can realize an average absorption of >92% in the entire solar spectrum (250 to 2500 nm). In particular, the 21-element nanoparticles achieve a considerably high solar steam efficiency of nearly 99% under one solar irradiation, with a water evaporation rate of 2.42 kg m-2 h-1, demonstrating a highly efficient photothermal conversion performance. The present approach creates a new strategy for uniformly mixing multi-metallic elements for exploring their unknown properties and various applications.

12.
Elife ; 112022 05 05.
Article in English | MEDLINE | ID: mdl-35511221

ABSTRACT

Thymic homing of hematopoietic progenitor cells (HPCs) is tightly regulated for proper T cell development. Previously we have identified a subset of specialized thymic portal endothelial cells (TPECs), which is important for thymic HPC homing. However, the underlying molecular mechanism still remains unknown. Here, we found that signal regulatory protein alpha (SIRPα) is preferentially expressed on TPECs. Disruption of CD47-SIRPα signaling in mice resulted in reduced number of thymic early T cell progenitors (ETPs), impaired thymic HPC homing, and altered early development of thymocytes. Mechanistically, Sirpa-deficient ECs and Cd47-deficient bone marrow progenitor cells or T lymphocytes demonstrated impaired transendothelial migration (TEM). Specifically, SIRPα intracellular ITIM motif-initiated downstream signaling in ECs was found to be required for TEM in an SHP2- and Src-dependent manner. Furthermore, CD47 signaling from migrating cells and SIRPα intracellular signaling were found to be required for VE-cadherin endocytosis in ECs. Thus, our study reveals a novel role of endothelial SIRPα signaling for thymic HPC homing for T cell development.


Subject(s)
CD47 Antigen , Endothelial Cells , Animals , Antigens, CD , CD47 Antigen/genetics , Cadherins , Endocytosis , Endothelial Cells/metabolism , Mice , Receptors, Immunologic , Thymocytes/metabolism
13.
J Clin Med ; 11(7)2022 Mar 28.
Article in English | MEDLINE | ID: mdl-35407477

ABSTRACT

Severe acute cholangitis is a life-threatening medical emergency. Endoscopic biliary drainage (EBD) or percutaneous transhepatic biliary drainage (PTBD) is usually used for biliary decompression. However, it can be risky to transport a critical patient to the radiology unit. We aimed to compare clinical outcomes between bedside, radiation-free EBD and fluoroscopic-guided PTBD in patients under critical care. METHODS: A retrospective study was conducted on critically ill patients admitted to the intensive care unit with biliary obstruction and cholangitis from January 2011 to April 2020. RESULTS: A total of 16 patients receiving EBD and 31 patients receiving PTBD due to severe acute cholangitis were analyzed. In the EBD group, biliary drainage was successfully conducted in 15 (93.8%) patients. Only one patient (6.25%) encountered post-procedure pancreatitis. The 30-day mortality rate was no difference between the 2 groups (32.72% vs. 31.25%, p = 0.96). Based on multivariate analysis, independent prognostic factors for the 30-day mortality were a medical history of malignancy other than pancreatobiliary origin (HR: 5.27, 95% confidence interval [CI]: 1.01-27.57) and emergent dialysis (HR: 7.30, 95% CI: 2.20-24.24). CONCLUSIONS: Bedside EBD is safe and as effective as percutaneous drainage in critically ill patients. It provides lower risks in patient transportation but does require experienced endoscopists to perform the procedure.

14.
Small ; 18(4): e2107265, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34908242

ABSTRACT

Designing heterogeneous interfaces and components at the nanoscale is proven effective for optimizing electromagnetic wave absorption and shielding properties, which can achieve desirable dielectric polarization and ferromagnetic resonances. However, it remains a challenge for the precise control of components and microstructures via an efficient synthesis approach. Here, the arc-discharged plasma method is proposed to synthesize core@shell structural high-entropy-alloy@graphite nanocapsules (HEA@C-NPs), in which the HEA nanoparticles are in situ encapsulated within a few layers of graphite through the decomposition of methane. In particular, the HEA cores can be designed via combinations of various transition elements, presenting the optimized interfacial impedance matching. As an example, the FeCoNiTiMn HEA@C-NPs obtain the minimum reflection loss (RLmin ) of -33.4 dB at 7.0 GHz (3.34 mm) and the efficient absorption bandwidth (≤-10 dB) of 5.45 GHz ranging from 12.55 to 18.00 GHz with an absorber thickness of 1.9 mm. The present approach can be extended to other carbon-coated complex components systems for various applications.

16.
Angew Chem Int Ed Engl ; 60(52): 27113-27118, 2021 Dec 20.
Article in English | MEDLINE | ID: mdl-34605601

ABSTRACT

Photothermal materials with broadband optical absorption and high conversion efficiency are intensively pursued to date. Here, proposing by the d-d interband transitions, we report an unprecedented high-entropy alloy FeCoNiTiVCrCu nanoparticles that the energy regions below and above the Fermi level (±4 eV) have been fully filled by the 3d transition metals, which realizes an average absorbance greater than 96 % in the entire solar spectrum (wavelength of 250 to 2500 nm). Furthermore, we also calculated the photothermal conversion efficiency and the evaporation rate towards the steam generation. Due to its pronounced full light capture and ultrafast local heating, our high-entropy-alloy nanoparticle-based solar steam generator has over 98 % efficiency under one sun irradiation, meanwhile enabling a high evaporation rate of 2.26 kg m-2 h-1 .

17.
ACS Appl Mater Interfaces ; 13(26): 30565-30575, 2021 Jul 07.
Article in English | MEDLINE | ID: mdl-34161064

ABSTRACT

Rapid degradation/destruction of chemical warfare agents, especially ones containing a phosphorous-fluorine bond, is of notable interest due to their extreme toxicity and typically rapid rate of human incapacitation. Recent studies of the hydrolytic destruction of a key nerve agent simulant, dimethyl 4-nitrophenylphosphate (DMNP), catalyzed by Zr6-based metal-organic frameworks (MOFs), have suggested deactivation of the active sites due to inhibition by the products as the reaction progresses. In this study, the interactions of two MOFs, NU-1000 and MOF-808, and two hydrolysis products, dimethyl phosphate (DMP) and ethyl methyl phosphonate (EMP), from the hydrolysis of the simulant (DMNP) and nerve agent ethyl methylphosphonofluoridate (EMPF), resembling the hydrolysis degradation product of the G-series nerve agent, Sarin (GB), have been investigated to deconvolute the effect of product inhibition from other effects on catalytic activity. Kinetic studies via in situ nuclear magnetic resonance spectroscopy indicated substantial product inhibition upon catalyst activity after several tens to several thousand turnovers, depending on specific conditions. Apparent product binding constants were obtained by fitting initial reaction rates at pH 7.0 and pH 10.5 to a Langmuir-Freundlich binding/adsorption model. For the fits, varying amounts/concentrations of candidate inhibitors were introduced before the start of catalytic hydrolysis. The derived binding constants proved suitable for quantitatively describing product inhibition effects upon reaction rates over the extended time course of simulant hydrolysis by aqua-ligand-bearing hexa-zirconium(IV) nodes.


Subject(s)
Catalysis/drug effects , Hydrolysis/drug effects , Metal-Organic Frameworks/chemistry , Nerve Agents/chemistry , Organophosphorus Compounds/chemistry , Paraoxon/analogs & derivatives , Kinetics , Paraoxon/chemistry , Zirconium/chemistry
18.
Chem Commun (Camb) ; 57(29): 3571-3574, 2021 Apr 14.
Article in English | MEDLINE | ID: mdl-33704273

ABSTRACT

The well-known MOF (metal-organic framework) linker tetrakis(p-benzoate)pyrene (TBAPy4-) lacks steric hindrance between its benzoates. Changing the 1,3,6,8-siting of benzoates in TBAPy4- to 4,5,9,10-siting introduces substantial steric hindrance and, in turn, enables the synthesis of a new hierarchically porous, she-type MOF Zr6(µ3-O)4(µ3-OH)4(C6H5COO)3(COO)3(TBAPy-2)3/2 (NU-601), where TBAPy-24- is the 4,5,9,10 isomer of TBAPy4-. NU-601 shows high catalytic activity for degradative hydrolysis of a simulant for G-type fluoro-phosphorus nerve agents.

19.
J Food Sci ; 86(3): 770-778, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33586786

ABSTRACT

Different geographical environment has a certain influence on the accumulation of fungi elements and chemical components. However, our knowledge is limited to elucidate the fungi elements in response to heterogeneous environmental and the quality differences among different habitats. Here, multielement analysis, FTIR spectrum, and feature-level fusion technique combined with chemometrics were used to study Wolfiporia cocos from different geographical areas, different sampling sites and different altitude sources. From the results, (1) there is significant difference in element content of samples from different sampling sites and no positive correlation with geographical ranges. (2) There is a correlation between elevation and elements, and relatively low elevation (<1,800 m) is conducive to the enrichment of elements. (3) From the perspective of elements, the W. cocos in Yuxi have relatively better quality. (4) FTIR and feature-level models can well realize origin identification. The SVM models are better than the PLS-DA models, and the feature-level model is better than the single FTIR models. In summary, this study demonstrated that the developed method was reliable and could realize the genuineness evaluation and origin identification of W. cocos. The results have implications for the establishment of the technology system of geographical traceability and the development of high-quality geographical indication products of W. cocos.


Subject(s)
Wolfiporia/chemistry , Wolfiporia/classification , Altitude , China , Geography , Minerals/analysis , Wolfiporia/growth & development
20.
J Am Chem Soc ; 142(50): 21110-21121, 2020 Dec 16.
Article in English | MEDLINE | ID: mdl-33263388

ABSTRACT

High-stability, zirconium-based metal-organic frameworks are attractive as heterogeneous catalysts and as model supports for uniform arrays of subsequently constructed heterogeneous catalysts-for example, MOF-node-grafted metal-oxy and metal-sulfur clusters. For hexa-Zr(IV)-MOFs characterized by nodes that are less than 12-connected, sites not used for linkers are ideally occupied by reactive and displaceable OH/H2O pairs. The desired pairs are ideal for grafting the aforementioned catalytic clusters, while aqua-ligand lability renders them effective for exposing highly Lewis-acidic Zr(IV) sites (catalytic sites) to candidate reactants. New single-crystal X-ray studies of an eight-connected Zr-MOF, NU-1000, reveal that conventional activation fully removes modulator ligands, but replaces them with three node-blocking formate ligands (from solvent decomposition) and only one OH/H2O pair, not four-a largely overlooked complication that now appears to be general for Zr-MOFs. Here we describe an alternative activation protocol that effectively removes modulators, avoids formate, and installs the full complement of terminal OH/H2O pairs. It does so via an unusual isolatable intermediate featuring eight aqua ligands and four non-ligated chlorides-again as supported by single-crystal X-ray data. We find that complete replacement of node-blocking modulators/formate with the originally envisioned OH/OH2 pairs has striking consequences; here we touch upon just three. First, elimination of unrecognized formate renders aqua ligands much more thermally labile, enabling open Zr(IV) sites to be obtained at lower temperature. Second, in the absence of formate, which otherwise links and locks pairs of node Zr(IV) ions, reversible removal of aqua ligands engenders reversible contraction of MOF meso- and micropores, as evidenced by X-ray diffraction. Third, formate replacement with OH/OH2 pairs renders NU-1000 ca.10× more active for catalytic hydrolytic degradation of a representative simulant of G-type chemical warfare agents.

SELECTION OF CITATIONS
SEARCH DETAIL
...