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1.
J Cell Mol Med ; 28(8): e18234, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38520214

RESUMO

Liver fibrosis is characterized by the activation and transformation of hepatic stellate cells (HSCs) induced by various injury factors. The degree of liver fibrosis can be significantly improved, but persistent injury factors present a significant therapeutic challenge. Hepatocytes are the most important parenchymal cell type in the liver. In this study, we explored the molecular mechanisms by which damaged liver cells activate HSCs through extracellular vesicles. We established a coculture model of LO2 and LX2 and validated its exosomal transmission activity. Subsequently, differentially expressed long noncoding RNAs (lncRNAs) were screened through RNA sequencing and their mechanisms of action as competing endogenous RNAs (ceRNAs) further confirmed using biological methods, such as FISH and luciferase assays. Damaged liver cells induced activation of LX2 and upregulation of liver fibrosis-related markers. Exosomes extracted and identified from the supernatant fraction contained differentially expressed lncRNA cytoskeleton regulator RNA (CYTOR) that competed with microRNA-125 (miR-125) for binding to glial cell line-derived neurotrophic factor (GDNF) in HSCs, in turn, promoting LX2 activation. MiR-125 could target and regulate both CYTOR and GDNF and vice versa, as verified using the luciferase assay. In an in vivo model, damaged liver extracellular vesicles induced the formation of liver fibrosis. Notably, downregulation of CYTOR within extracellular vesicles effectively inhibited liver fibrosis. The lncRNA CYTOR in exosomes of damaged liver cells is upregulated and modulates the expression of downstream GDNF through activity as a ceRNA, providing an effective mechanism for activation of HSCs.


Assuntos
Exossomos , MicroRNAs , RNA Longo não Codificante , Humanos , Células Estreladas do Fígado/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Exossomos/genética , Exossomos/metabolismo , Regulação da Expressão Gênica , Hepatócitos/metabolismo , Cirrose Hepática/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Luciferases/metabolismo
2.
J Am Chem Soc ; 146(29): 20477-20493, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-38982945

RESUMO

Cobalt complexes with chiral quinox ligands effectively promote the enantioselective conjugate addition of enones using aryl, heteroaryl, and alkenyl halides and sulfonates. Additionally, a cobalt complex with a strongly donating diphosphine, BenzP*, successfully catalyzes the asymmetric reductive arylation and alkenylation of α,ß-unsaturated amides. Both catalytic systems show broad scopes and tolerance of sensitive functional groups. Both reactions can be scaled up with low loadings of cobalt catalysts. Experimental results and density functional theory (DFT) calculations suggest a new mechanism of elementary 1,4-addition of aryl cobalt(I) complexes.

3.
Mol Biol Rep ; 51(1): 507, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622406

RESUMO

BACKGROUND: Our previous research has demonstrated that hypoxic preconditioning (HPC) can improve spatial learning and memory abilities in adult mice. Adult hippocampal neurogenesis has been associated with learning and memory. The Neurogenic locus notch homolog protein (Notch) was involved in adult hippocampal neurogenesis, as well as in learning and memory. It is currently unclear whether the Notch pathway regulates hippocampal neuroregeneration by modifying the DNA methylation status of the Notch gene following HPC. METHOD: The HPC animal model and cell model were established through repeated hypoxia exposure using mice and the mouse hippocampal neuronal cell line HT22. Step-down test was conducted on HPC mice. Real-time PCR and Western blot analysis were used to assess the mRNA and protein expression levels of Notch1 and hairy and enhancer of split1 (HES1). The presence of BrdU-positive cells and Notch1 expression in the hippocampal dental gyrus (DG) were examined with confocal microscopy. The methylation status of the Notch1 was analyzed using methylation-specific PCR (MS-PCR). HT22 cells were employed to elucidate the impact of HPC on Notch1 in vitro. RESULTS: HPC significantly improved the step-down test performance of mice with elevated levels of mRNA and protein expression of Notch1 and HES1 (P < 0.05). The intensities of the Notch1 signal in the control group, the H group and the HPC group were 2.62 ± 0.57 × 107, 2.87 ± 0.84 × 107, and 3.32 ± 0.14 × 107, respectively, and the number of BrdU (+) cells in the hippocampal DG were 1.83 ± 0.54, 3.71 ± 0.64, and 7.29 ± 0.68 respectively. Compared with that in C and H group, the intensity of the Notch1 signal and the number of BrdU (+) cells increased significantly in HPC group (P < 0.05). The methylation levels of the Notch1 promoter 0.82 ± 0.03, 0.65 ± 0.03, and 0.60 ± 0.02 in the C, H, and HPC groups, respectively. The methylation levels of Notch1 decreased significantly (P < 0.05). The effect of HPC on HT22 cells exhibited similarities to that observed in the hippocampus. CONCLUSION: HPC may confer neuroprotection by activating the Notch1 signaling pathway and regulating its methylation level, resulting in the regeneration of hippocampal neurons.


Assuntos
Metilação de DNA , Hipocampo , Camundongos , Animais , Metilação de DNA/genética , Bromodesoxiuridina/metabolismo , Hipocampo/metabolismo , Hipóxia/genética , Hipóxia/metabolismo , Receptores Notch/metabolismo , RNA Mensageiro/metabolismo , Receptor Notch1/genética , Receptor Notch1/metabolismo
4.
BMC Musculoskelet Disord ; 25(1): 405, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38783225

RESUMO

Femoral head varus is an important complication in intertrochanteric fracture patients treated with proximal femoral nail anti-rotation (PFNA) fixation. Theoretically, extending the length of the intramedullary nail could optimize fixation stability by lengthening the force arm. However, whether extending the nail length can optimize patient prognosis is unclear. In this study, a review of imaging data from intertrochanteric fracture patients with PFNA fixation was performed, and the length of the intramedullary nail in the femoral trunk and the distance between the lesser trochanter and the distal locking screw were measured. The femoral neck varus status was judged at the 6-month follow-up. The correlation coefficients between nail length and femoral neck varus angle were computed, and linear regression analysis was used to determine whether a change in nail length was an independent risk factor for femoral neck varus. Moreover, the biomechanical effects of different nail lengths on PFNA fixation stability and local stress distribution have also been verified by numerical mechanical simulations. Clinical review revealed that changes in nail length were not significantly correlated with femoral head varus and were also not an independent risk factor for this complication. In addition, only slight biomechanical changes can be observed in the numerical simulation results. Therefore, commonly used intramedullary nails should be able to meet the needs of PFNA-fixed patients, and additional procedures for longer nail insertion may be unnecessary.


Assuntos
Pinos Ortopédicos , Fixação Intramedular de Fraturas , Fraturas do Quadril , Humanos , Fenômenos Biomecânicos/fisiologia , Fixação Intramedular de Fraturas/instrumentação , Fixação Intramedular de Fraturas/métodos , Fixação Intramedular de Fraturas/efeitos adversos , Feminino , Masculino , Idoso , Fraturas do Quadril/cirurgia , Fraturas do Quadril/diagnóstico por imagem , Cabeça do Fêmur/cirurgia , Cabeça do Fêmur/diagnóstico por imagem , Idoso de 80 Anos ou mais , Fatores de Risco , Pessoa de Meia-Idade , Simulação por Computador
5.
J Am Chem Soc ; 145(30): 16464-16473, 2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37477355

RESUMO

Cobalt complexes of chiral pyrox ligands catalyzed enantioselective reductive couplings of nonconjugated iododienes with aryl iodides or alkenyl bromides. The reaction enabled stereoselective syntheses of 5-7-membered azacycles carrying quaternary stereocenters. Mechanistically, cross-electrophile selectivity originated from selective coupling of alkylcobalt(I) complexes generated after cyclization with aryl iodides.

6.
J Psychiatry Neurosci ; 48(6): E452-E460, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38123242

RESUMO

BACKGROUND: Interhemispheric cooperation is one of the most prominent functional architectures of the human brain. In patients with schizophrenia, interhemispheric cooperation deficits have been reported using increasingly powerful neurobehavioural and neuroimaging measures. However, these methods rely in part on the assumption of anatomic symmetry between hemispheres. In the present study, we explored interhemispheric cooperation deficits in schizophrenia using a newly developed index, connectivity between functionally homotopic voxels (CFH), which is unbiased by hemispheric asymmetry. METHODS: Patients with schizophrenia and age- and sexmatched healthy controls underwent multimodal MRI, and whole-brain CFH maps were constructed for comparison between groups. We examined the correlations of differing CFH values between the schizophrenia and control groups using various neurotransmitter receptor and transporter densities. RESULTS: We included 86 patients with schizophrenia and 86 matched controls in our analysis. Patients with schizophrenia showed significantly lower CFH values in the frontal lobes, left postcentral gyrus and right inferior temporal gyrus, and significantly greater CFH values in the right caudate nucleus than healthy controls. Moreover, the differing CFH values in patients with schizophrenia were significantly correlated with positive symptom score and illness duration. Functional connectivity within frontal lobes was significantly reduced at the voxel cluster level compared with healthy controls. Finally, the abnormal CFH map of patients with schizophrenia was spatially associated with the densities of the dopamine D1 and D2 receptors, fluorodopa, dopamine transporter, serotonin transporter and acetylcholine transporter. CONCLUSION: Regional abnormalities in interhemispheric cooperation may contribute to the clinical symptoms of schizophrenia. These CFH abnormalities may be associated with dysfunction in neurotransmitter systems strongly implicated in schizophrenia.


Assuntos
Esquizofrenia , Humanos , Esquizofrenia/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Imageamento por Ressonância Magnética/métodos , Núcleo Caudado
7.
BMC Musculoskelet Disord ; 24(1): 881, 2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-37953269

RESUMO

PURPOSE: This study was to investigate the feasibility and treatment effect of using modified Kirschner wire (K-wire) percutaneous rotation prying reduction combined with Elastic Stable Intramedullary Nailing (ESIN) in children with Judet IV radial neck fracture. METHODS: A retrospective analysis was conducted on 47 children with Judet IV radial neck fracture who underwent treatment with modified K-wire percutaneous rotation prying reduction combined with ESIN from April 2019 to November 2022, including 25 males and 22 females, with an average age of 8.79 years old (ranging from 5 to 14). The study recorded the surgical time, fluoroscopy time, reduction time, and reduction quality evaluated according to the Metaizeau radiological standard. During the last follow-up, the flexion-extension and forearm rotation function of the affected and healthy sides were recorded, and the Mayo Elbow Performance index was used to evaluate the elbow joint function. RESULTS: The average duration of the operation was 25.51 min (ranging from 14 to 43 min), with a mode of 2 reset times (ranging from 1 to 5) and 8 fluoroscopic times (ranging from 4 to 15). Based on the Metaizeau radiological standard for assessing reduction quality, 45 cases were deemed excellent, while 2 cases were considered good. Following 3-4 weeks of postoperative long-arm cast immobilization, exercises were performed to promote elbow joint and forearm rotation. The ESIN was removed after satisfactory fracture healing around 4 months postoperatively. The average follow-up period was 26.79 months (ranging from 5 to 48). At the final follow-up, the range of motion for the affected limb in flexion, extension, pronation, and supination was (140.23 ± 4.80)°, (4.43 ± 3.98)°, (84.09 ± 4.97)°, and (83.83 ± 4.55)°, respectively. There was no statistically significant difference compared to the healthy side, which had a range of motion of (141.36 ± 3.27)°, (5.28 ± 2.25)°, (85.66 ± 3.20)°, and (84.98 ± 2.57)° (P > 0.05). According to the Mayo Elbow Performance index, 44 cases were rated as excellent and 1 case was considered good. CONCLUSION: The modified K-wire percutaneous rotation prying reduction combined with ESIN is an effective treatment for severe radial neck fractures in children. This technique offers several advantages, including the ability to easily "capture" significantly displaced radial heads, achieve rapid and accurate reduction, and reduce radiation exposure.


Assuntos
Fixação Intramedular de Fraturas , Fraturas da Cabeça e do Colo do Rádio , Fraturas do Rádio , Masculino , Feminino , Humanos , Criança , Fios Ortopédicos , Fixação Intramedular de Fraturas/métodos , Pinos Ortopédicos , Estudos Retrospectivos , Resultado do Tratamento , Fixação Interna de Fraturas/métodos , Fraturas do Rádio/diagnóstico por imagem , Fraturas do Rádio/cirurgia , Extremidade Superior , Amplitude de Movimento Articular
8.
Sensors (Basel) ; 23(18)2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37765981

RESUMO

With the proliferation of unmanned aerial vehicles (UAVs) in both commercial and military use, the public is paying increasing attention to UAV identification and regulation. The micro-Doppler characteristics of a UAV can reflect its structure and motion information, which provides an important reference for UAV recognition. The low flight altitude and small radar cross-section (RCS) of UAVs make the cancellation of strong ground clutter become a key problem in extracting the weak micro-Doppler signals. In this paper, a clutter suppression method based on an orthogonal matching pursuit (OMP) algorithm is proposed, which is used to process echo signals obtained by a linear frequency modulated continuous wave (LFMCW) radar. The focus of this method is on the idea of sparse representation, which establishes a complete set of environmental clutter dictionaries to effectively suppress clutter in the received echo signals of a hovering UAV. The processed signals are analyzed in the time-frequency domain. According to the flicker phenomenon of UAV rotor blades and related micro-Doppler characteristics, the feature parameters of unknown UAVs can be estimated. Compared with traditional signal processing methods, the method based on OMP algorithm shows advantages in having a low signal-to-noise ratio (-10 dB). Field experiments indicate that this approach can effectively reduce clutter power (-15 dB) and successfully extract micro-Doppler signals for identifying different UAVs.

9.
Int J Mol Sci ; 24(14)2023 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-37511187

RESUMO

Isocitrate dehydrogenase (IDH) can be divided into NAD+-dependent and NADP+-dependent types based on the coenzyme specificity. It is worth noting that some IDHs exhibit dual coenzyme specificity characteristics. Herein, a dual coenzyme-dependent IDH from Umbonibacter Marinipuiceus (UmIDH) was expressed, purified, and identified in detail for the first time. SDS-PAGE and Gel filtration chromatography analyses showed that UmIDH is an 84.7 kDa homodimer in solution. The Km values for NAD+ and NADP+ are 1800.0 ± 64.4 µM and 1167.7 ± 113.0 µM in the presence of Mn2+, respectively. Meanwhile, the catalytic efficiency (kcat/Km) of UmIDH is only 2.3-fold greater for NADP+ than NAD+. The maximal activity for UmIDH occurred at pH 8.5 (with Mn2+) or pH 8.7 (with Mg2+) and at 35 °C (with Mn2+ or Mg2+). Heat inactivation assay revealed that UmIDH sustained 50% of maximal activity after incubation at 57 °C for 20 min with either Mn2+ or Mg2+. Moreover, three putative core coenzyme binding residues (R345, L346, and V352) of UmIDH were evaluated by site-directed mutagenesis. This recent work identified a unique dual coenzyme-dependent IDH and achieved the groundbreaking bidirectional modification of this specific IDH's coenzyme dependence for the first time. This provides not only a reference for the study of dual coenzyme-dependent IDH, but also a basis for the investigation of the coenzyme-specific evolutionary mechanisms of IDH.


Assuntos
Coenzimas , NAD , Coenzimas/metabolismo , NAD/metabolismo , NADP/metabolismo , Isocitrato Desidrogenase/metabolismo , Sequência de Aminoácidos , Cinética
10.
Int J Mol Sci ; 23(19)2022 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-36233280

RESUMO

The lack of detailed information on nutritional requirement results in limited feeding in Siberian sturgeon. In this study, resveratrol, a versatile natural extract, was supplemented in the daily diet, and the digestive ability and microbiome were evaluated in the duodena and valvular intestines of Siberian sturgeon. The results showed that resveratrol increased the activity of pepsin, α-amylase, and lipase, which was positively associated with an increase in the digestive ability, but it did not influence the final body weight. Resveratrol improved the digestive ability probably by distinctly enhancing intestinal villus height. Microbiome analysis revealed that resveratrol changed the abundance and composition of the microbial community in the intestine, principally in the duodenum. Random forests analysis found that resveratrol significantly downregulated the abundance of potential pathogens (Citrobacter freundii, Vibrio rumoiensis, and Brucella melitensis), suggesting that resveratrol may also improve intestinal health. In summary, our study revealed that resveratrol improved digestive ability and intestinal health, which can contribute to the development of functional feed in Siberian sturgeon.


Assuntos
Ração Animal , Pepsina A , Ração Animal/análise , Animais , Dieta , Peixes , Intestinos/química , Lipase , Resveratrol/farmacologia , alfa-Amilases
11.
Angew Chem Int Ed Engl ; 60(6): 2828-2832, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33140526

RESUMO

Nickel-catalyzed intermolecular Heck reaction of cycloalkenes proceeds well with aryl triflates, mesylates and tosylates in excellent enantiomeric ratios. The asymmetric reductive Heck reaction also works with a 2-cyclopentenone ketal, which is equivalent to conjugate arylation of the enone itself.

12.
Microb Cell Fact ; 19(1): 21, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32013959

RESUMO

BACKGROUND: (+)-Nootkatone is a highly valued sesquiterpenoid compound, exhibiting a typical grapefruit aroma and various desired biological activities for use as aromatics and pharmaceuticals. The high commercial demand of (+)-nootkatone is predominately met by chemical synthesis, which entails the use of environmentally harmful reagents. Efficient synthesis of (+)-nootkatone via biotechnological approaches is thus urgently needed to satisfy its industrial demand. However, there are only a limited number of studies that report the de novo synthesis of (+)-nootkatone from simple carbon sources in microbial cell factories, and with relatively low yield. RESULTS: As the direct precursor of (+)-nootkatone biosynthesis, (+)-valencene was first produced in large quantities in Saccharomyces cerevisiae by overexpressing (+)-valencene synthase CnVS of Callitropsis nootkatensis in combination with various mevalonate pathway (MVA) engineering strategies, including the expression of CnVS and farnesyl diphosphate synthase (ERG20) as a fused protein, overexpression of a truncated form of the rate-limiting enzyme 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase (tHMG1), and downregulating the squalene synthase enzyme (ERG9). These approaches altogether brought the production of (+)-valencene to 217.95 mg/L. Secondly, we addressed the (+)-valencene oxidation by overexpressing the Hyoscyamus muticus premnaspirodiene oxygenase (HPO) variant (V482I/A484I) and cytochrome P450 reductase (ATR1) from Arabidopsis thaliana. However, (+)-valencene was predominantly oxidized to ß-nootkatol and only minor amounts of (+)-nootkatone (9.66 mg/L) were produced. We further tackled the oxidation of ß-nootkatol to (+)-nootkatone by screening various dehydrogenases. Our results showed that the short-chain dehydrogenase/reductase (SDR) superfamily dehydrogenases ZSD1 of Zingiber zerumbet and ABA2 of Citrus sinensis were capable of effectively catalyzing ß-nootkatol oxidation to (+)-nootkatone. The yield of (+)-nootkatone increased to 59.78 mg/L and 53.48 mg/L by additional overexpression of ZSD1 and ABA2, respectively. CONCLUSION: We successfully constructed the (+)-nootaktone biosynthesis pathway in S. cerevisiae by overexpressing the (+)-valencene synthase CnVS, cytochrome P450 monooxygenase HPO, and SDR family dehydrogenases combined with the MVA pathway engineering, providing a solid basis for the whole-cell production of (+)-nootkatone. The two effective SDR family dehydrogenases tested in this study will serve as valuable enzymatic tools in further optimizing (+)-nootkatone production.


Assuntos
Biotecnologia/métodos , Engenharia Metabólica , Proteínas de Plantas/metabolismo , Sesquiterpenos Policíclicos/metabolismo , Saccharomyces cerevisiae/metabolismo , Alquil e Aril Transferases/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Redutases-Desidrogenases de Cadeia Curta/metabolismo
13.
BMC Musculoskelet Disord ; 20(1): 369, 2019 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-31399086

RESUMO

BACKGROUND: Percutaneous transforaminal endoscopic discectomy (PTED) is widely used for the treatment of lumbar disc herniation. Facetectomy in PTED is necessary for accessing the intraspinal region and for decompressing the exiting nerve roots in patients who suffer from hypertrophy of the facet joints. However, this may increase morbidity in failed back surgery syndrome (FBSS) and has not been clearly elucidated. METHODS: A three-dimensional lumbosacral model was reconstructed and validated. And corresponding models after PTED with one-quarter and one-half excisions of the superior articular process were reconstructed. The maximum shear stress on the annulus in L5, von Mises stress of the facet cartilage, maximum principle capsular strain and deformation of the lumbosacral model were calculated using finite element methods. RESULTS: Calculated results show no significant differences in the complete model and the model with one-quarter excision of the superior articular process, but all biomechanical indexes have been deteriorated under most of the loading conditions tested in the model with one-half excision of the superior articular process. CONCLUSIONS: Less facetectomy is better because it may reduce the risk of biomechanical deterioration and consequently, that of FBSS.


Assuntos
Discotomia Percutânea/métodos , Endoscopia/métodos , Síndrome Pós-Laminectomia/prevenção & controle , Degeneração do Disco Intervertebral/cirurgia , Deslocamento do Disco Intervertebral/cirurgia , Discotomia Percutânea/efeitos adversos , Endoscopia/efeitos adversos , Síndrome Pós-Laminectomia/etiologia , Humanos , Imageamento Tridimensional , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Imageamento por Ressonância Magnética , Masculino , Modelos Anatômicos , Sacro/diagnóstico por imagem , Sacro/cirurgia , Tomografia Computadorizada por Raios X , Adulto Jovem
14.
Chemistry ; 24(67): 17756-17766, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30230070

RESUMO

Photochromic diarylethene derivatives, which can reversibly switch the fluorescence of adjacent fluorophores between the ON and OFF states under light irradiation, have been widely used to construct photoswitchable materials. Herein, eight dithienylethene (DTE) groups are integrated onto one polyhedral oligomeric silsesquioxane (POSS) core, obtaining a novel super molecular photoswitch. After being doped into conjugated polymer nanoparticles, the POSS-DTE8 molecules show a higher contrast on/off photoswitching performance and a quicker responsive speed than free DTE molecules at same molar concentration of photochromic units. This enhanced photoswitching efficiency is attributed to the increased molecular interaction of the ring-open form and lowered energy of the ring-closed form of the DTE units on the POSS core, which is beneficial for the ring-closing reaction and subsequent energy transfer between photoswitch and fluorophores. In addition, POSS-DTE8 also exhibits good photomodulation behavior in the conjugated polymer film, giving it potential applications in optical devices.

15.
Environ Sci Technol ; 52(15): 8627-8637, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-29952547

RESUMO

Nanoscale zerovalent iron (nZVI) likely finds its application in source zone remediation. Two approaches to modify nZVI have been reported: bimetal (Fe-Me) and sulfidated nZVI (S-nZVI). However, previous research has primarily focused on enhancing particle reactivity with these two modifications under more plume-like conditions. In this study, we systematically compared the trichloroethene (TCE) dechlorination pathway, rate, and electron selectivity of Fe-Me (Me: Pd, Ni, Cu, and Ag), S-nZVI, and nZVI with excess TCE simulating source zone conditions. TCE dechlorination on Fe-Me was primarily via hydrogenolysis while that on S-nZVI and nZVI was mainly via ß-elimination. The surface-area normalized TCE reduction rate ( k'SA) of Fe-Pd, S-nZVI, Fe-Ni, Fe-Cu, and Fe-Ag were ∼6800-, 190-, 130-, 20-, and 8-fold greater than nZVI. All bimetallic modification enhanced the competing hydrogen evolution reaction (HER) while sulfidation inhibited HER. Fe-Cu and Fe-Ag negligibly enhanced electron utilization efficiency (εe) while Fe-Pd, Fe-Ni, and S-nZVI dramatically increased εe from 2% to ∼100%, 69%, and 72%, respectively. Adsorbed atomic hydrogen was identified to be responsible for the TCE dechlorination on Fe-Me but not on S-nZVI. The enhanced dechlorination rate along with the reduced HER of S-nZVI can be explained by that FeS conducting major electrons mediated TCE dechlorination while Fe oxides conducting minor electrons mediated HER.


Assuntos
Tricloroetileno , Halogenação , Hidrogênio , Concentração de Íons de Hidrogênio , Ferro
16.
J Toxicol Environ Health A ; 80(22): 1222-1229, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28880816

RESUMO

Epigenetic processes such as DNA methylation are essential for processes of gene expression in normal mammalian development. DNA methyltransferases (DNMT) are responsible for initiating and maintaining DNA methylation. It is known that 5-Aza-CdR, an inhibitor of DNMT induces cytotoxicity by reducing DNMT activity in various tumor cell lines. However, disturbances in neuronal DNA methylation may also play a role in altered brain functions. Thus, it was of interest to determine whether alterations in DNA methylation might be associated with neuronal functions by using 5-Aza-CdR, on mouse hippocampus-derived neuronal HT22 cell line. In particular, the aim of this study was to investigate the effects of 5-Aza-CdR on cell growth inhibition, cell cycle arrest, apoptosis as well as the expression levels of DNMT in HT22 cells. HT22 cells were incubated with 5 or 20 µmol/L 5-Aza-CdR for 24 h. Data showed that 5-Aza-CdR at both concentrations significantly inhibited proliferation of HT22 cells and exacerbated cytoplasmic vacuolization. Flow cytometry analysis demonstrated that 5-Aza-CdR treatment at both concentrations decreased early apoptosis but enhanced late apoptosis. Cell cycle analysis illustrated that 5-Aza-CdR treatment induced S phase arrest. Further, incubation with 5-Aza-CdR produced a down-regulation in expression of mRNA and protein DNMT1 and 3A but no marked changes were noted in DNMT 3B and p21 expression. In addition, DNMT1 activity was significantly decreased at both 5-Aza-CdR concentrations. Evidence indicates that 5-Aza-CdR induced cytotoxicity was associated with altered mRNA and protein expression of DNMT 1 and 3A associated with reduced DNMT1 activity in HT22 cells which might affect brain functions.


Assuntos
Azacitidina/análogos & derivados , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Azacitidina/toxicidade , Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , DNA Metiltransferase 3A , Decitabina , Hipocampo/citologia , Camundongos
17.
J Org Chem ; 81(22): 10683-10687, 2016 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-27786466

RESUMO

A novel efficient approach to optically pure bridging chiral calix[4]arenes through a homologous anionic ortho-Fries rearrangement of inherently chiral calix[4]arenes was presented for the first time. As a result, two pairs of N,N'-dimethylformamidyl-substituted bridging chiral p-tert-butylcalix[4]arene enantiomers were facilely obtained. Their absolute configurations were determined through ROESY analysis, ECD comparison, and X-ray crystallographic analysis.

18.
Polymers (Basel) ; 16(13)2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-39000701

RESUMO

Porous membrane technology has garnered significant attention in the fields of separation and biology due to its remarkable contributions to green chemistry and sustainable development. The porous membranes fabricated from polylactic acid (PLA) possess numerous advantages, including a low relative density, a high specific surface area, biodegradability, and excellent biocompatibility. As a result, they exhibit promising prospects for various applications, such as oil-water separation, tissue engineering, and drug release. This paper provides an overview of recent research advancements in the fabrication of PLA membranes using electrospinning, the breath-figure method, and the phase separation method. Firstly, the principles of each method are elucidated from the perspective of pore formation. The correlation between the relevant parameters and pore structure is discussed and summarized, subsequently followed by a comparative analysis of the advantages and limitations of each method. Subsequently, this article presents the diverse applications of porous PLA membranes in tissue engineering, oil-water separation, and other fields. The current challenges faced by these membranes, however, encompass inadequate mechanical strength, limited production efficiency, and the complexity of pore structure control. Suggestions for enhancement, as well as future prospects, are provided accordingly.

19.
Adv Sci (Weinh) ; 11(25): e2402915, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38641884

RESUMO

The silicon (Si) anode is prone to forming a high electric field gradient and concentration gradient on the electrode surface under high-rate conditions, which may destroy the surface structure and decrease cycling stability. In this study, a ferroelectric (BaTiO3) interlayer and field polarization treatment are introduced to set up a built-in field, which optimizes the transport mechanisms of Li+ in solid and liquid phases and thus enhances the rate performance and cycling stability of Si anodes. Also, a fast discharging and slow charging phenomenon is observed in a half-cell with a high reversible capacity of 1500.8 mAh g-1 when controlling the polarization direction of the interlayer, which means a fast charging and slow discharging property in a full battery and thus is valuable for potential applications in commercial batteries. Simulation results demonstrated that the built-in field plays a key role in regulating the Li+ concentration distribution in the electrolyte and the Li+ diffusion behavior inside particles, leading to more uniform Li+ diffusion from local high-concentration sites to surrounding regions. The assembled lithium-ion battery with a BaTiO3 interlayer exhibited superior electrochemical performance and long-term cycling life (915.6 mAh g-1 after 300 cycles at a high current density of 4.2 A g-1). The significance of this research lies in exploring a new approach to improve the performance of lithium-ion batteries and providing new ideas and pathways for addressing the challenges faced by Si-based anodes.

20.
Neural Netw ; 172: 106088, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38159510

RESUMO

Inspired by visual-tactile cross-modal bidirectional mapping of the human brain, this paper introduces a novel approach to bidirectional mapping between visual and tactile data, an area not fully explored in the predominantly unidirectional existing studies. First, we adopt separate Variational AutoEncoder (VAE) models for visual and tactile data. Furthermore, we introduce a conditional flow model built on the VAE latent feature space, enabling cross-modal bidirectional mapping between visual and tactile data using one model. The experimental results show that our method achieves excellent performance in terms of the similarity between the generated data and the original data (Structural Similarity Index (SSIM) of visual data: 0.58, SSIM of tactile data: 0.80), the classification accuracy on generated data (visual data: 91.60%, tactile data: 88.05%), and the zero-shot classification accuracy between generated data and language (visual data: 44.49%, tactile data: 45.03%). To the best of our knowledge, the method proposed in this paper is the first one to utilize a single model to achieve bidirectional mapping between visual and tactile data. Our model and code will be made public after the acceptance of the paper.


Assuntos
Encéfalo , Tato , Humanos , Mapeamento Encefálico/métodos
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