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2.
Rev Esp Enferm Dig ; 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38967270

ABSTRACT

BACKGROUND: Gastric venous bleeding is one of the most common adverse events in liver cirrhosis. The therapeutic effect of isolated gastric varices is relatively clear. However, there is no appropriate clinical and endoscopic treatment for extensive variceal bleeding in the gastric fundus and body. METHODS: In this patient with non-isolated gastric varices, we decided to perform endoscopic multi-point ligation of the obvious varices in the gastric fundus and body. RESULTS: In this patient, endoscopic treatment of gastric varices with bleeding after surgery achieved a significant therapeutic effect. Reexamination of gastroscopy at 3 months after operation showed that multiple scars were formed in the gastric fundus and fundus, and no obvious varices were found. CONCLUSIONS: For patients with non-isolated gastric varices, endoscopic multi-point ligation is a safe and effective treatment option for the varices with obvious gastric fundus and body.

3.
Bioresour Technol ; : 131071, 2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38971391

ABSTRACT

The isomerization of glucose is a crucial step for biomass valorization to downstream chemicals. Herein, highly dispersed MgO doped biochar (BM-0.5@450) was prepared from rice straw via a solvent-free ball milling pretreatment and pyrolysis under nitrogen conditions. The nano-MgO doped biochar demonstrated enhanced conversion of glucose in water at low temperatures. A 31 % yield of fructose was obtained from glucose over BM-0.5@450 at 50 °C with 80.0 % selectivity. At 60 °C for 140 min, BM-0.5@450 achieved a 32.5 % yield of fructose. Compared to catalyst synthesized from conventional impregnation method (IM@450), the BM-0.5@450 catalyst shows much higher fructose yields (32.5 % vs 25.9 %), which can be attributed to smaller crystallite size of MgO (11.32 nm vs 19.58 nm) and homogenous distribution. The mechanism study shows that the activated MgOH+·OH- group by water facilitated the deprotonation process leading to the formation of key intermediate enediol.

4.
Sci Transl Med ; 16(752): eadl5931, 2024 Jun 19.
Article in English | MEDLINE | ID: mdl-38896605

ABSTRACT

Clinical treatment of acute myeloid leukemia (AML) largely relies on intensive chemotherapy. However, the application of chemotherapy is often hindered by cardiotoxicity. Patient sequence data revealed that angiotensin II receptor type 1 (AGTR1) is a shared target between AML and cardiovascular disease (CVD). We found that inhibiting AGTR1 sensitized AML to chemotherapy and protected the heart against chemotherapy-induced cardiotoxicity in a human AML cell-transplanted mouse model. These effects were regulated by the AGTR1-Notch1 axis in AML cells and cardiomyocytes from mice. In mouse cardiomyocytes, AGTR1 was hyperactivated by AML and chemotherapy. AML leukemogenesis increased the expression of the angiotensin-converting enzyme and led to increased production of angiotensin II, the ligand of AGTR1, in an MLL-AF9-driven AML mouse model. In this model, the AGTR1-Notch1 axis regulated a variety of genes involved with cell stemness and chemotherapy resistance. AML cell stemness was reduced after Agtr1a deletion in the mouse AML cell transplant model. Mechanistically, Agtr1a deletion decreased γ-secretase formation, which is required for transmembrane Notch1 cleavage and release of the Notch1 intracellular domain into the nucleus. Using multiomics, we identified AGTR1-Notch1 signaling downstream genes and found decreased binding between these gene sequences with Notch1 and chromatin enhancers, as well as increased binding with silencers. These findings describe an AML/CVD association that may be used to improve AML treatment.


Subject(s)
Cardiotoxicity , Disease Models, Animal , Leukemia, Myeloid, Acute , Receptor, Angiotensin, Type 1 , Receptor, Notch1 , Animals , Leukemia, Myeloid, Acute/pathology , Leukemia, Myeloid, Acute/metabolism , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/genetics , Humans , Receptor, Angiotensin, Type 1/metabolism , Receptor, Angiotensin, Type 1/genetics , Cardiotoxicity/metabolism , Cardiotoxicity/pathology , Receptor, Notch1/metabolism , Mice , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/drug effects , Myocytes, Cardiac/pathology , Signal Transduction/drug effects , Cell Line, Tumor , Amyloid Precursor Protein Secretases/metabolism , Heart/drug effects
5.
J Hazard Mater ; 475: 134889, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-38878436

ABSTRACT

Both polycyclic aromatic hydrocarbons (PAHs) and heavy metals persist in the environment and are toxic to organisms. Their co-occurrence makes any of them difficult to remove during bioremediation and poses challenges to environmental management and public health. Microorganisms capable of effectively degrading PAHs and detoxifying heavy metals concurrently are required to improve the bioremediation process. In this study, we isolated a new strain, Sphingobium sp. SJ10-10, from an abandoned coking plant and demonstrated its capability to simultaneously degrade 92.6 % of 75 mg/L phenanthrene and reduce 90 % of 3.5 mg/L hexavalent chromium [Cr(VI)] within 1.5 days. Strain SJ10-10 encodes Rieske non-heme iron ring-hydroxylating oxygenases (RHOs) to initiate PAH degradation. Additionally, a not-yet-reported protein referred to as Sphingobium chromate reductase (SchR), with low sequence identity to known chromate reductases, was identified to reduce Cr(VI). SchR is distributed across different genera and can be classified into two classes: one from Sphingobium members and the other from non-Sphingobium species. The widespread presence of SchR in those RHO-containing Sphingobium members suggests that they are excellent candidates for bioremediation. In summary, our study demonstrates the simultaneous removal of PAHs and Cr(VI) by strain SJ10-10 and provides valuable insights into microbial strategies for managing complex pollutant mixtures.


Subject(s)
Biodegradation, Environmental , Chromates , Dioxygenases , Oxidoreductases , Polycyclic Aromatic Hydrocarbons , Sphingomonadaceae , Sphingomonadaceae/enzymology , Sphingomonadaceae/metabolism , Dioxygenases/metabolism , Dioxygenases/genetics , Polycyclic Aromatic Hydrocarbons/metabolism , Polycyclic Aromatic Hydrocarbons/chemistry , Chromates/metabolism , Oxidoreductases/metabolism , Chromium/metabolism , Phenanthrenes/metabolism
6.
Invest Ophthalmol Vis Sci ; 65(6): 39, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38935032

ABSTRACT

Purpose: This study aimed to explore protective effects and potential mechanism of ectoine, a natural osmoprotectant, on ocular surface mucin production in dry eye disease. Methods: A dry eye model was established in C57BL/6 mice exposed to desiccating stress (DS) with untreated (UT) mice as controls. DS mice were topically treated with 2.0% ectoine or PBS vehicle. Corneal epithelial defects were assessed by Oregon Green Dextran (OGD) fluorescent staining. Conjunctival goblet cells, ocular mucins, and T help (Th) cytokines were evaluated by immunofluorescent staining or ELISA, and RT-qPCR. Results: Compared with UT mice, corneal epithelial defects were detected as strong punctate OGD fluorescent staining in DS mice with vehicle, whereas ectoine treatment largely reduced OGD staining to near-normal levels. Conjunctival goblet cell density and cell size decreased markedly in DS mice, but was significantly recovered by ectoine treatment. The protein production and mRNA expression of two gel-forming secreted MUC5AC and MUC2, and 4 transmembrane mucins, MUC1, MUC4, MUC16, and MUC15, largely decreased in DS mice, but was restored by ectoine. Furthermore, Th2 cytokine IL-13 was inhibited, whereas Th1 cytokine IFN-γ was stimulated at protein and mRNA levels in conjunctiva and draining cervical lymph nodes (CLNs) of DS mice, leading to decreased IL-13/IFN-γ ratio. Interestingly, 2.0% ectoine reversed their alternations and restored IL-13/IFN-γ balance. Conclusions: Our findings demonstrate that topical ectoine significantly reduces corneal damage, and enhances goblet cell density and mucin production through restoring imbalanced IL-13/IFN-γ signaling in murine dry eye model. This suggests therapeutic potential of natural osmoprotectant ectoine for dry eye disease.


Subject(s)
Disease Models, Animal , Dry Eye Syndromes , Goblet Cells , Interferon-gamma , Interleukin-13 , Mice, Inbred C57BL , Mucins , Animals , Dry Eye Syndromes/metabolism , Dry Eye Syndromes/drug therapy , Mice , Goblet Cells/metabolism , Goblet Cells/drug effects , Goblet Cells/pathology , Interferon-gamma/metabolism , Mucins/metabolism , Mucins/biosynthesis , Mucins/genetics , Interleukin-13/metabolism , Conjunctiva/metabolism , Conjunctiva/drug effects , Conjunctiva/pathology , Enzyme-Linked Immunosorbent Assay , Female , Epithelium, Corneal/metabolism , Epithelium, Corneal/drug effects , Real-Time Polymerase Chain Reaction , RNA, Messenger/genetics , RNA, Messenger/metabolism , Amino Acids, Diamino
7.
Int J Biol Macromol ; 273(Pt 2): 132971, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38880442

ABSTRACT

The salt-responsiveness of Pickering emulsions has significantly influenced their applications due to the large amount of salt on the surface of plant leaves. The present study provided a maleic anhydride-functionalized cellulose nanocrystal-stabilized high internal phase Pickering emulsion (MACNCs-HIPPEs) that was stable to high-concentration salt and used for pesticide delivery. The stability of MACNCs-HIPPEs was investigated by adjusting the oil-phase volume fraction (φ), the MACNCs concentration, NaCl dosages, and the rheological properties. The high internal phase Pickering emulsion was obtained at φ of 0.8 and MACNCs concentration of 2wt% and showed excellent salt stability (NaCl, 1200 mM) and significant storage stability (60 days). The sustained release of imidacloprid (IMI) from imidacloprid-loaded MACNCs-HIPPEs (IMI@MACNCs-HIPPEs) showed a positive correlation to the temperature (15°C, 25°C, 35°C), indicating clear thermo-responsiveness of the prepared pesticide formulation. The test of spread and retention of IMI@MACNCs-HIPPEs on the leaf surface showed a significant advantage compared with the commercial IMI water dispersible granules (CG). All the advantages mentioned above showed the excellent potential of the MACNCs-HIPPEs in delivering lipophilic pesticides.


Subject(s)
Cellulose , Emulsions , Maleic Anhydrides , Nanoparticles , Neonicotinoids , Pesticides , Cellulose/chemistry , Nanoparticles/chemistry , Maleic Anhydrides/chemistry , Emulsions/chemistry , Pesticides/chemistry , Neonicotinoids/chemistry , Nitro Compounds/chemistry , Temperature , Drug Liberation
8.
Sensors (Basel) ; 24(11)2024 Jun 02.
Article in English | MEDLINE | ID: mdl-38894380

ABSTRACT

X-ray images typically contain complex background information and abundant small objects, posing significant challenges for object detection in security tasks. Most existing object detection methods rely on complex networks and high computational costs, which poses a challenge to implement lightweight models. This article proposes Fine-YOLO to achieve rapid and accurate detection in the security domain. First, a low-parameter feature aggregation (LPFA) structure is designed for the backbone feature network of YOLOv7 to enhance its ability to learn more information with a lighter structure. Second, a high-density feature aggregation (HDFA) structure is proposed to solve the problem of loss of local details and deep location information caused by the necked feature fusion network in YOLOv7-Tiny-SiLU, connecting cross-level features through max-pooling. Third, the Normalized Wasserstein Distance (NWD) method is employed to alleviate the convergence complexity resulting from the extreme sensitivity of bounding box regression to small objects. The proposed Fine-YOLO model is evaluated on the EDS dataset, achieving a detection accuracy of 58.3% with only 16.1 M parameters. In addition, an auxiliary validation is performed on the NEU-DET dataset, the detection accuracy reaches 73.1%. Experimental results show that Fine-YOLO is not only suitable for security, but can also be extended to other inspection areas.

9.
Crit Rev Food Sci Nutr ; : 1-13, 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38835159

ABSTRACT

The global rise in life expectancy corresponds with a delay in childbearing age among women. Ovaries, seen as the chronometers of female physiological aging, demonstrate features of sped up aging, evidenced by the steady decline in both the quality and quantity of ovarian follicles from birth. The multifaceted pathogenesis of ovarian aging has kindled intensive research interest from the biomedical and pharmaceutical sectors. Novel studies underscore the integral roles of gut microbiota in follicular development, lipid metabolism, and hormonal regulation, forging a nexus with ovarian aging. In this review, we outline the role of gut microbiota in ovarian function (follicular development, oocyte maturation, and ovulation), compile and present gut microbiota alterations associated with age-related ovarian aging. We also discuss potential strategies for alleviating ovarian aging from the perspective of gut microbiota, such as fecal microbiota transplantation and probiotics.

11.
Plant Physiol Biochem ; 212: 108783, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38824694

ABSTRACT

Cimicifuga dahurica (C. dahurica) is an important medicinal plant in the northern region of China. The best supplemental light environment helps plant growth, development, and metabolism. In this study, we used two-year-old seedlings as experimental materials. The white light as the control (CK). The different ratios of red (R) and blue (B) combined light were supplemented (T1, 2R: 1B, 255.37 µmol m-2·s-1; T2, 3R: 1B, 279.69 µmol m-2·s-1; T3, 7R: 1B, 211.16 µmol m-2·s-1). The growth characteristics, photosynthetic pigment content, photosynthesis and chlorophyll fluorescence parameters, and primary metabolite content were studied in seedlings. The results showed that: 1) The fresh weight from shoot, root, and total fresh weight were significantly (P < 0.05) increased under T2 and T3 treatment. 2) The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll (Chl) were significantly (P < 0.05) increased under T2 treatment, and carotenoid (car) content was reduced. 3) The photochemical quenching (qP), the actual photosynthetic efficiency of PSII (Y(II)), and the photosynthetic electron transfer rate (ETR) from leaves were significantly (P < 0.05) increased under T1 treatment. The Net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) were significantly (P < 0.05) increased under T2 and T3 treatments. 4) A total of 52 primary metabolites were detected in C. dahurica leaves. Compared with CK, 14, 15, and 18 differential metabolites were screened under T1, T2, and T3 treatments. In addition, D-xylose, D-glucose, glycerol, glycolic acid, and succinic acid were significantly (P < 0.05) accumulated under the T2 treatment, which could regulate the TCA cycle metabolism pathway. The correlation analysis suggested that plant growth was promoted by regulating the change of D-mannose content in galactinol metabolism and amino sugar and nucleotide sugar metabolism. In summary, the growth of C. dahurica was improved under T2 treatment.


Subject(s)
Chlorophyll , Cimicifuga , Light , Photosynthesis , Chlorophyll/metabolism , Cimicifuga/metabolism , Seedlings/growth & development , Seedlings/metabolism , Carotenoids/metabolism , Plant Leaves/metabolism , Plant Leaves/growth & development , Chlorophyll A/metabolism
12.
Plant Commun ; : 100942, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38720463

ABSTRACT

Feralization is an important evolutionary process, but the mechanisms behind it remain poorly understood. Here, we use the ancient fiber crop ramie (Boehmeria nivea (L.) Gaudich.) as a model to investigate genomic changes associated with both domestication and feralization. We first produced a chromosome-scale de novo genome assembly of feral ramie and investigated structural variations between feral and domesticated ramie genomes. Next, we gathered 915 accessions from 23 countries, comprising cultivars, major landraces, feral populations, and the wild progenitor. Based on whole-genome resequencing of these accessions, we constructed the most comprehensive ramie genomic variation map to date. Phylogenetic, demographic, and admixture signal detection analyses indicated that feral ramie is of exoferal or exo-endo origin, i.e., descended from hybridization between domesticated ramie and the wild progenitor or ancient landraces. Feral ramie has higher genetic diversity than wild or domesticated ramie, and genomic regions affected by natural selection during feralization differ from those under selection during domestication. Ecological analyses showed that feral and domesticated ramie have similar ecological niches that differ substantially from the niche of the wild progenitor, and three environmental variables are associated with habitat-specific adaptation in feral ramie. These findings advance our understanding of feralization, providing a scientific basis for the excavation of new crop germplasm resources and offering novel insights into the evolution of feralization in nature.

13.
J Neurosci ; 44(27)2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38789262

ABSTRACT

We previously showed that orexin neurons are activated by hypoxia and facilitate the peripheral chemoreflex (PCR)-mediated hypoxic ventilatory response (HVR), mostly by promoting the respiratory frequency response. Orexin neurons project to the nucleus of the solitary tract (nTS) and the paraventricular nucleus of the hypothalamus (PVN). The PVN contributes significantly to the PCR and contains nTS-projecting corticotropin-releasing hormone (CRH) neurons. We hypothesized that in male rats, orexin neurons contribute to the PCR by activating nTS-projecting CRH neurons. We used neuronal tract tracing and immunohistochemistry (IHC) to quantify the degree that hypoxia activates PVN-projecting orexin neurons. We coupled this with orexin receptor (OxR) blockade with suvorexant (Suvo, 20 mg/kg, i.p.) to assess the degree that orexin facilitates the hypoxia-induced activation of CRH neurons in the PVN, including those projecting to the nTS. In separate groups of rats, we measured the PCR following systemic orexin 1 receptor (Ox1R) blockade (SB-334867; 1 mg/kg) and specific Ox1R knockdown in PVN. OxR blockade with Suvo reduced the number of nTS and PVN neurons activated by hypoxia, including those CRH neurons projecting to nTS. Hypoxia increased the number of activated PVN-projecting orexin neurons but had no effect on the number of activated nTS-projecting orexin neurons. Global Ox1R blockade and partial Ox1R knockdown in the PVN significantly reduced the PCR. Ox1R knockdown also reduced the number of activated PVN neurons and the number of activated tyrosine hydroxylase neurons in the nTS. Our findings suggest orexin facilitates the PCR via nTS-projecting CRH neurons expressing Ox1R.


Subject(s)
Corticotropin-Releasing Hormone , Neurons , Orexin Receptor Antagonists , Orexin Receptors , Orexins , Rats, Sprague-Dawley , Solitary Nucleus , Animals , Male , Corticotropin-Releasing Hormone/metabolism , Orexins/metabolism , Rats , Neurons/metabolism , Neurons/physiology , Neurons/drug effects , Solitary Nucleus/metabolism , Solitary Nucleus/physiology , Solitary Nucleus/drug effects , Orexin Receptor Antagonists/pharmacology , Orexin Receptors/metabolism , Hypoxia/metabolism , Triazoles/pharmacology , Azepines/pharmacology , Paraventricular Hypothalamic Nucleus/metabolism , Paraventricular Hypothalamic Nucleus/drug effects , Paraventricular Hypothalamic Nucleus/physiology
14.
Chem Asian J ; : e202400181, 2024 May 05.
Article in English | MEDLINE | ID: mdl-38705859

ABSTRACT

In Li-ion batteries, the origin of memory effect in Al-doped Li4Ti5O12 has been revealed as the reversible Al-ion switching between 8a and 16c sites in the spinel structure, but it is still not clear about that for olivine LiFePO4, which is one of the most important cathode materials. In this work, a series of Na-doped and Ti-doped LiFePO4 are prepared in a high-temperature solid-state method, electrochemically investigated in Li-ion batteries and characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Magic-Angle-Spinning Nuclear Magnetic Resonance (MAS NMR). Compared with non-doped LiFePO4, the Ti doping can simultaneously suppress the memory effect and the Li-Fe anti-site, while they are simultaneously enhanced by the Na doping. Meanwhile, the Ti doping improves the electrochemical performance of LiFePO4, opposite to the Na doping. Accordingly, a schematic diagram of phase transition is proposed to interpret the memory effect of LiFePO4, in which the memory effect is attributed to the defect of Li-Fe anti-site.

15.
Sci Total Environ ; 935: 173343, 2024 Jul 20.
Article in English | MEDLINE | ID: mdl-38777069

ABSTRACT

Niche convergence or conservatism have been proposed as essential mechanisms underlying elevational plant community assembly in tropical mountain ecosystems. Subtropical mountains, compared to tropical mountains, are likely to be shaped by a mixing of different geographic affinities of species and remain somehow unclear. Here, we used 31 0.1-ha permanent plots distributed in subtropical forests on the eastern and western aspects of the Gaoligong Mountains, southwest China between 1498 m and 3204 m a.sl. to evaluate how niche-based and biogeographic processes shape tree community assembly along elevational gradients. We analyzed the elevational patterns of taxonomic, phylogenetic and functional diversity, as well as of individual traits, and assessed the relative importance of environmental effects on these diversity measures. We then classified tree species as being either tropical affiliated or temperate affiliated and estimated their contribution to the composition of biogeographic affinities. Species richness decreased with elevation, and species composition showed apparent turnover across the aspects and elevations. Most traits exhibited convergent patterns across the entire elevational gradient. Phylogenetic and functional diversity showed opposing patterns, with phylogenetic diversity increasing and functional diversity decreasing with elevation. Soil nutrients, especially phosphorus and nitrogen, appeared to be the main abiotic variables driving the elevational diversity patterns. Communities at lower elevations were occupied by tropical genera, while highlands contained species of tropical and temperate biogeographic affinities. Moreover, the high phylogenetic diversity at high elevations were likely due to differences in evolutionary history between temperate and tropical species. Our results highlight the importance of niche convergence of tropical species and the legacy of biogeographic history on the composition and structure of subtropical mountain forests. Furthermore, limited soil phosphorus caused traits divergence and the partitioning for different forms of phosphorus may explain the high biodiversity found in phosphorus-limited subtropical forests.


Subject(s)
Altitude , Biodiversity , Forests , Trees , China , Phylogeny , Ecosystem , Tropical Climate
16.
Rev Esp Enferm Dig ; 2024 May 20.
Article in English | MEDLINE | ID: mdl-38767030

ABSTRACT

A 16-year-old woman complained of intermittent epigastric pain for one year. The gastroscopy, colonoscopy and laboratory findings were normal. Physical examination was unremarkable other than upper abdominal tenderness. The symptom was not relieved in past medical treatment. The abdominal computed tomography (CT) scan revealed appendix wall swelling and suspected appendicitis. Endoscopic retrograde appendicitis therapy (ERAT) with eyeMax (Micro-tech, China) was proposed to perform after informed consent obtained. A colonoscopy with a transparent cap (Olympus, Japan) attached to the tip was inserted into the cecum, and advanced the level of appendicular orifice. Subsequently, the Gerlach's valve was pushed aside using the transparent cap. Finally, the eyeMax was placed in the appendicular orifice, slowly moved forward in appendicular lumen. The eyeMax showed a lot of appendicular stones, and irrigated repeatedly. The stones were expulsed smoothly. The patient was discharged two days later without recurrent epigastric pain on follow-up and to date.

17.
Rev Esp Enferm Dig ; 2024 May 20.
Article in English | MEDLINE | ID: mdl-38767035

ABSTRACT

A 69-year-old woman was diagnosed with a duodenal adenoma near major duodenal papilla during cancer screening examination (Figure 1A). Therefore, endoscopic mucosal resection (EMR) was proposed to remove the duodenal lesion. Unfortunately, satisfactory visualization of the duodenal lesion was not obtained during gastroscopic operation. Unexpectedly, duodenoscopy provided optimal visualization of the duodenal lesion. Consequently, the "sandwich method" using duodenoscopy-gastroscopy-duodenoscopy was successfully performed to remove the challenging duodenal lesion. Firstly, the duodenoscopy was used to create a submucosal bleb through injecting saline containing 0.3 % indigo carmine. Subsequently, the gastroscopy with a transparent capwas used to remove the duodenal lesion with en bloc resection. Then, the duodenoscopy was reused to close the mucosal defect. Finally, pathologic examination showed a tubule-villous adenoma. The patient was recovered uneventfully, and discharged 2 days later.

18.
Carbohydr Polym ; 337: 122088, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38710544

ABSTRACT

The construction of the preferred orientation structure by stretching is an efficient strategy to fabricate high-performance cellulose film and it is still an open issue whether crystalline structure or amorphous molecular chain is the key factor in determining the enhanced mechanical performance. Herein, uniaxial stretching with constant width followed by drying in a stretching state was carried out to cellulose hydrogels with physical and chemical double cross-linking networks, achieving high-performance regenerated cellulose films (RCFs) with an impressive tensile strength of 154.5 MPa and an elastic modulus of 5.4 GPa. The hierarchical structure of RCFs during uniaxial stretching and drying was systematically characterized from micro- to nanoscale, including microscopic morphology, crystalline structure as well as relaxation behavior at a molecular level. The two-dimensional correlation spectra of dynamic mechanical analysis and Havriliak-Negami fitting results verified that the enhanced mechanical properties of RCFs were mainly attributed to the stretch-induced tight packing and restricted relaxation of amorphous molecular chains. The new insight concerning the contribution of molecular chains in the amorphous region to the enhancement of mechanical performance for RCFs is expected to provide valuable guidance for designing and fabricating high-performance eco-friendly cellulose-based films.

19.
Plant Divers ; 46(2): 229-237, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38807909

ABSTRACT

Chinese Assam tea (Camellia sinensis var. assamica) is an important tea crop with a long history of cultivation in Yunnan, China. Despite its potential value as a genetic resource, its genetic diversity and domestication/breeding history remain unclear. To address this issue, we genotyped 469 ancient tea plant trees representing 26 C. sinensis var. assamica populations, plus two of its wild relatives (six and three populations of C. taliensis and C. crassicolumna, respectively) using 16 nuclear microsatellite loci. Results showed that Chinese Assam tea has a relatively high, but comparatively lower gene diversity (HS = 0.638) than the wild relative C. crassicolumna (HS = 0.658). Clustering in STRUCTURE indicated that Chinese Assam tea and its two wild relatives formed distinct genetic groups, with considerable interspecific introgression. The Chinese Assam tea accessions clustered into three gene pools, corresponding well with their geographic distribution. However, NewHybrids analysis indicated that 68.48% of ancient Chinese Assam tea plants from Xishuangbanna were genetic intermediates between the Puer and Lincang gene pools. In addition, 10% of the ancient Chinese Assam tea individuals were found to be hybrids between Chinese Assam tea and C. taliensis. Our results suggest that Chinese Assam tea was domesticated separately in three gene pools (Puer, Lincang and Xishuangbanna) in the Mekong River valley and that the hybrids were subsequently selected during the domestication process. Although the domestication history of Chinese Assam tea in southwestern Yunnan remains complex, our results will help to identify valuable genetic resources that may be useful in future tea breeding programs.

20.
ACS Appl Mater Interfaces ; 16(20): 26044-26056, 2024 May 22.
Article in English | MEDLINE | ID: mdl-38717586

ABSTRACT

Carbon material has widely been utilized in the synthesis of efficient carbon-supported Pt (Pt/C) catalysts, in which the structural properties greatly influence the electrocatalytic performances of Pt/C catalysts. However, the effects of intrinsic defects in carbon supports on the performance of the alkaline hydrogen evolution reaction (HER) have not been systematically investigated. Herein, porous carbon supports with different degrees of intrinsic defects were prepared by a simple template-assisted strategy, and the resulting samples were systematically studied by various analytical methods. The results suggested that the presence of abundant intrinsic defects (vacancy and topological defects) in the carbon support was advantageous in terms of favoring the dispersion and anchoring of Pt species, promoting electron transfer between Pt atoms and the carbon support, and tuning the electronic states of Pt species. These features improved the HER performance of Pt/C catalysts. Compared to the nontemplate-assisted carbon-supported Pt catalyst (Pt/NTC) with an overpotential of 178 mV, the optimized template-assisted carbon-supported Pt catalyst (Pt/TC) exhibited a lower overpotential of 58 mV at 10 mA cm-2. Besides, the Pt/TC catalyst displayed better HER durability than the Pt/NTC catalyst owing to its strong metal-support interaction. The DFT calculations confirmed the important role played by intrinsic defects (vacancy and topological defects) in stabilizing Pt atoms, with Pt-C3 coordination identified as the most favorable structure for improving the HER performance of Pt. Overall, novel insights on the significant contribution of intrinsic defects in porous carbon supports on the HER performances of Pt/C catalysts were provided, useful for future design and fabrication of advanced carbon-supported catalysts or other carbon-based electrode materials.

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