Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 918
Filtrar
1.
Sci Adv ; 10(27): eadn2031, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38968351

RESUMEN

Three-dimensional (3D) perception is vital to drive mobile robotics' progress toward intelligence. However, state-of-the-art 3D perception solutions require complicated postprocessing or point-by-point scanning, suffering computational burden, latency of tens of milliseconds, and additional power consumption. Here, we propose a parallel all-optical computational chipset 3D perception architecture (Aop3D) with nanowatt power and light speed. The 3D perception is executed during the light propagation over the passive chipset, and the captured light intensity distribution provides a direct reflection of the depth map, eliminating the need for extensive postprocessing. The prototype system of Aop3D is tested in various scenarios and deployed to a mobile robot, demonstrating unprecedented performance in distance detection and obstacle avoidance. Moreover, Aop3D works at a frame rate of 600 hertz and a power consumption of 33.3 nanowatts per meta-pixel experimentally. Our work is promising toward next-generation direct 3D perception techniques with light speed and high energy efficiency.

2.
Nat Commun ; 15(1): 5714, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38977701

RESUMEN

Genetic code expansion has emerged as a powerful tool for precisely introducing unnatural chemical structures into proteins to improve their catalytic functions. Given the high catalytic propensity of histidine in the enzyme pocket, increasing the chemical diversity of catalytic histidine could result in new characteristics of biocatalysts. Herein, we report the genetically encoded Nδ-Vinyl Histidine (δVin-H) and achieve the wild-type-like incorporation efficiency by the evolution of pyrrolysyl tRNA synthetase. As histidine usually acts as the nucleophile or the metal ligand in the catalytic center, we replace these two types of catalytic histidine to δVin-H to improve the performance of the histidine-involved catalytic center. Additionally, we further demonstrate the improvements of the hydrolysis activity of a previously reported organocatalytic esterase (the OE1.3 variant) in the acidic condition and myoglobin (Mb) catalyzed carbene transfer reactions under the aerobic condition. As histidine is one of the most frequently used residues in the enzyme catalytic center, the derivatization of the catalytic histidine by δVin-H holds a great potential to promote the performance of biocatalysts.


Asunto(s)
Dominio Catalítico , Histidina , Histidina/metabolismo , Histidina/química , Histidina/genética , Mioglobina/genética , Mioglobina/química , Mioglobina/metabolismo , Biocatálisis , Catálisis , Aminoacil-ARNt Sintetasas/genética , Aminoacil-ARNt Sintetasas/metabolismo , Aminoacil-ARNt Sintetasas/química , Esterasas/genética , Esterasas/metabolismo , Esterasas/química , Hidrólisis , Escherichia coli/genética , Escherichia coli/metabolismo
4.
Plants (Basel) ; 13(12)2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38931076

RESUMEN

The impact of climates on the radial growth of muti-species remains insufficiently understood in the climate-sensitive southeastern Tibetan Plateau, and this hampers an effective assessment of forest growth under the background of global warming. Here, we studied the growth-climate relationships of three major species (Abies georgei, Larix potaninii, and Picea likiangensis) on the Baima Snow Mountain (BSM) by using dendrochronology methods. We constructed basal area increment (BAI) residual chronologies based on the dated ring-width measurements and correlated the chronologies with four climate factors. We also calculated the contributions of each climate factor to species growth. We found that photothermal conditions played a more important role than moisture in modulating radial growth, and P. likiangensi presented the strongest sensitivity to climate change among the three species. The growing season (June and July) temperature positively affected the radial growth of three species. Winter (previous December and current January) SD negatively impacted the tree growth of A. georgei and P. likiangensis. Significant correlations between growth and precipitation were detected only in A. georgei (January and May). Warming since the beginning of the 1950s promoted the growth of A. georgei and P. likiangensis, while the same effect on L. potaninii growth was found in the recent 50 years.

5.
Cancer Cell Int ; 24(1): 221, 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38937742

RESUMEN

BACKGROUND: Glioma is considered the most common primary malignant tumor of the central nervous system. Although traditional treatments have not achieved satisfactory outcomes, recently, targeted therapies for glioma have shown promising efficacy. However, due to the single-target nature of targeted therapy, traditional targeted therapies are ineffective; thus, novel therapeutic targets are urgently needed. METHODS: The gene expression data for glioma patients were derived from the GEO (GSE4290, GSE50161), TCGA and CGGA databases. Next, the upregulated genes obtained from the above databases were cross-analyzed, finally, 10 overlapping genes (BIRC5, FOXM1, EZH2, CDK1, KIF11, KIF4A, NDC80, PBK, RRM2, and TOP2A) were ultimately screened and only KIF4A expression has the strongest correlation with clinical characteristics in glioma patients. Futher, the TCGA and CGGA database were utilized to explore the correlation of KIF4A expression with glioma prognosis. Then, qRT-PCR and Western blot was used to detect the KIF4A mRNA and protein expression level in glioma cells, respectively. And WZ-3146, the small molecule inhibitor targeting KIF4A, were screened by Cmap analysis. Subsequently, the effect of KIF4A knockdown or WZ-3146 treatment on glioma was measured by the MTT, EdU, Colony formation assay and Transwell assay. Ultimately, GSEA enrichment analysis was performed to find that the apoptotic pathway could be regulated by KIF4A in glioma, in addition, the effect of WZ-3146 on glioma apoptosis was detected by flow cytometry and Western blot. RESULTS: In the present study, we confirmed that KIF4A is abnormally overexpressed in glioma. In addition, KIF4A overexpression is a key indicator of glioma prognosis; moreover, suppressing KIF4A expression can inhibit glioma progression. We also discovered that WZ-3146, a small molecule inhibitor of KIF4A, can induce apoptosis in glioma cells and exhibit antiglioma effects. CONCLUSION: In conclusion, these observations demonstrated that targeting KIF4A can inhibit glioma progression. With further research, WZ-3146, a small molecule inhibitor of KIF4A, could be combined with other molecular targeted drugs to cooperatively inhibit glioma progression.

6.
Food Res Int ; 190: 113905, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38945555

RESUMEN

Bee bread is a product of honeybees, which collect and ferment pollen, that contains highly nutritious and easily digestible active substances. However, its nutritional composition varies significantly with fermentation strains and seasonal changes. To unveil the patterns of microbial community and nutritional component changes in bee bread across seasons, we employed high-throughput techniques to assess the diversity of bacteria and fungi in bee bread. The results indicated that the compositions of bacteria and fungi in bee bread undergo significant seasonal variation, with noticeable changes in the microbial diversity of bee bread from different bee species. Subsequently, metabolomic analysis revealed high activity of glycerophospholipid metabolism in bee bread. Furthermore, our analysis identifaied noteworthy differences in nutritional components, including pH values, sugar content, and free amino acid levels, in bee bread across different seasons.


Asunto(s)
Bacterias , Microbiota , Valor Nutritivo , Estaciones del Año , Abejas/microbiología , Animales , Bacterias/clasificación , Fermentación , Aminoácidos/análisis , Hongos/clasificación , Polen/química , Pan/análisis , Pan/microbiología , Concentración de Iones de Hidrógeno , Metabolómica
7.
Comput Struct Biotechnol J ; 23: 2230-2239, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38827230

RESUMEN

Alzheimer's disease (AD) is an age-related neurodegenerative disorder. Transgenic and pharmacological AD models are extensively studied to understand AD mechanisms and drug discovery. However, they are time-consuming and relatively costly, which hinders the discovery of potential anti-AD therapeutics. Here, we established a new model of AD in larval zebrafish by co-treatment with aluminum chloride (AlCl3) and D-galactose (D-gal) for 72 h. In particular, exposure to 150 µM AlCl3 + 40 mg/mL D-gal, 200 µM AlCl3 + 30 mg/mL D-gal, or 200 µM AlCl3 + 40 mg/mL D-gal successfully induced AD-like symptoms and aging features. Co-treatment with AlCl3 and D-gal caused significant learning and memory deficits, as well as impaired response ability and locomotor capacity in the plus-maze and light/dark test. Moreover, increased acetylcholinesterase and ß-galactosidase activities, ß-amyloid 1-42 deposition, reduced telomerase activity, elevated interleukin 1 beta mRNA expression, and enhanced reactive oxygen species production were also observed. In conclusion, our zebrafish model is simple, rapid, effective and affordable, incorporating key features of AD and aging, thus may become a unique and powerful tool for high-throughput screening of anti-AD compounds in vivo.

9.
Clin Case Rep ; 12(6): e8959, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38817707

RESUMEN

Key Clinical Message: Ultrasound-guided core needle biopsy combined with immunohistochemistry and molecular testing could improve the diagnostic accuracy of bone metastases from follicular thyroid carcinoma, help to predict distant metastasis and prognosis. Abstract: Metastatic thyroid follicular carcinoma presenting initially with bone lesion is uncommon, its prime symptom is gradual onset, localized pain. Patient with bone metastasis who were diagnosed before thyroidectomy had a higher rate of mortality, clinician should be cautious in eliciting the clinical history and this insidious symptom in middle age group, carry out further examination. We are presenting two case reports of a follicular thyroid carcinoma with bone metastasis, ultrasound-guided core needle biopsy combined with immunohistochemistry (IHC) were carried out by our clinical team to determine the source and nature of the tumor, relevant literature was reviewed, molecular testing was discussed, we believe core needle biopsy combined with IHC and molecular testing improve the diagnostic accuracy of bone metastases from follicular thyroid carcinoma.

10.
Adv Sci (Weinh) ; : e2306890, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38816931

RESUMEN

In spite of recent advances in the field of undernutrition, current dietary therapy relying on the supply of high protein high calorie formulas is still plagued with transient recovery of impaired organs resulting in significant relapse of cases. This is partly attributed to the inadequacy of current research models in recapitulating clinical undernutrition for mechanistic exploration. Using 1636 Macaca fascicularis monkeys, a human-relevant criterion for determining undernutrition weight-for-age z-score (WAZ), with a cutoff point of ≤ -1.83 is established as the benchmark for identifying undernourished nonhuman primates (U-NHPs). In U-NHPs, pathological anomalies in multi-organs are revealed. In particular, severe dysregulation of hepatic lipid metabolism characterized by impaired fatty acid oxidation due to mitochondria dysfunction, but unlikely peroxisome disorder, is identified as the anchor metabolic aberration in U-NHPs. Mitochondria dysfunction is typified by reduced mito-number, accumulated long-chain fatty acids, and disruption of OXPHOS complexes. Soy peptide-treated U-NHPs increase in WAZ scores, in addition to attenuated mitochondria dysfunction and restored OXPHOS complex levels. Herein, innovative criteria for identifying U-NHPs are developed, and unknown molecular mechanisms of undernutrition are revealed hitherto, and it is further proved that soypeptide supplementation reprogramed mitochondrial function to re-establish lipid metabolism balance and mitigated undernutrition.

11.
Theor Appl Genet ; 137(6): 129, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38740615

RESUMEN

KEY MESSAGE: Through comprehensive genomic and transcriptomic analyses, we identified a set of 23 genes that act up- or downstream of erucic acid content (EAC) production in rapeseed seeds. We selected example genes to showcase the distribution of single nucleotide polymorphisms, haplotypes associated with EAC phenotypes, and the creation of molecular markers differentiating low EAC and high EAC genotypes. Erucic acid content (EAC) is a crucial trait in rapeseed, with low LEAC oil recognized for its health benefits and high EA oil holding industrial value. Despite its significance, the genomic consequences of intensive LEAC-cultivar selection and the genetic basis underlying EA regulation remain largely unexplored. To address this knowledge gap, we conducted selective signal analyses, genome-wide association studies (GWAS), and transcriptome analyses. Our investigation unveiled the genetic footprints resulting from LEAC selection in germplasm populations, drawing attention to specific loci that contribute to enriching diversity. By integrating GWAS and transcriptome analyses, we identified a set of 23 genes that play a significant role in determining EAC in seeds or are downstream consequences of EA-level alterations. These genes have emerged as promising candidates for elucidating the potential mechanisms governing EAC in rapeseed. To exemplify the findings, we selected specific genes to demonstrate the distribution of single nucleotide polymorphisms and haplotypes associated with different EAC phenotypes. Additionally, we showcased to develop molecular markers distinguishing between LEAC and high EAC genotypes.


Asunto(s)
Brassica napus , Ácidos Erucicos , Polimorfismo de Nucleótido Simple , Semillas , Semillas/genética , Semillas/crecimiento & desarrollo , Brassica napus/genética , Ácidos Erucicos/metabolismo , Fenotipo , Haplotipos , Transcriptoma , Estudio de Asociación del Genoma Completo , Genotipo , Perfilación de la Expresión Génica , Genómica/métodos , Regulación de la Expresión Génica de las Plantas , Sitios de Carácter Cuantitativo
12.
J Agric Food Chem ; 72(22): 12529-12540, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38764367

RESUMEN

In this study, edible bird's nest (EBN) was proven to be a suitable source of bioactive peptides via enzymatic hydrolysis. The ultrafiltration component of the EBN peptides (EBNPs, Mw < 3 000 Da) could be responsible for moderate moisture retention and filaggrin synthesis. It was found that EBNP had a great capacity to protect HaCaT keratinocytes from DNA damage caused by UVB-irradiation and enhance wound healing by increasing the migratory and proliferative potential of cells. Furthermore, the external application of EBNP could effectively repair high glycolic acid concentration-induced skin burns in mice. A total of 1 188 peptides, predominantly the hydrophobic amino acids (e.g., Leu, Val, Tyr, Phe), were identified in the EBNP by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Molecular docking showed that hydrophobic tripeptides from EBNP had a good binding affinity to proton-dependent oligopeptide transporter PepT1. Our data indicated that the hydrophobic amino acid-rich EBNP plays an important role in skin wound healing.


Asunto(s)
Aves , Proteínas Filagrina , Péptidos , Hidrolisados de Proteína , Piel , Cicatrización de Heridas , Animales , Cicatrización de Heridas/efectos de los fármacos , Hidrolisados de Proteína/química , Hidrolisados de Proteína/metabolismo , Ratones , Piel/química , Piel/metabolismo , Humanos , Péptidos/química , Péptidos/metabolismo , Aves/metabolismo , Simulación del Acoplamiento Molecular , Queratinocitos/metabolismo , Queratinocitos/efectos de los fármacos , Espectrometría de Masas en Tándem , Masculino , Proteínas Aviares/química , Proteínas Aviares/metabolismo , Transporte Biológico , Células HaCaT , Absorción Cutánea
13.
Adv Healthc Mater ; : e2301985, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38776526

RESUMEN

Infected diabetic wound (DW) presents a prolonged and challenging healing process within the field of regenerative medicine. The effectiveness of conventional drug therapies is hindered by their limited ability to reach deep tissues and promote adequate wound healing rates. Therefore, there is an imperative to develop drug delivery systems that can penetrate deep tissues while exhibiting multifunctional properties to expedite wound healing. In this study, w e devised a soluble microneedle (MN) patch made of γ-PGA, featuring multiple arrays, which w as loaded with core-shell structured nanoparticles (NPs) known as Ag@MSN@CeO2, to enhance the healing of infected DWs. The NP comprises a cerium dioxide (CeO2) core with anti-inflammatory and antioxidant properties, a mesoporous silica NP (MSN) shell with angiogenic characteristics, and an outermost layer doped with Ag to combat bacterial infections. W e demonstrated that the MN platform loaded with Ag@MSN@CeO2 successfully penetrated deep tissues for effective drug delivery. These MN tips induced the formation of multiple regenerative sites at various points, leading to antibacterial, reactive oxygen species-lowering, macrophage ecological niche-regulating, vascular regeneration-promoting, and collagen deposition-promoting effects, thus significantly expediting the healing process of infected DWs. Considering these findings, the multifunctional MN@Ag@MSN@CeO2 patch exhibits substantial potential for clinical applications in the treatment of infected DW.

14.
BMC Cardiovasc Disord ; 24(1): 252, 2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38750443

RESUMEN

BACKGROUND: Interleukin-17 (IL-17) has been hypothesized to be involved in ischemic cardiovascular disease (ICVD). However, the association of IL-17 with ICVD remained unclear. The aim of this study was to systematically analyze the available evidence regarding the association between IL-17 and ICVD. METHODS: We searched the PubMed, Web of Science, Cochrane Library, and Embase databases up to October 2023 to identify publications on the association between IL-17 and ICVD. The merged results were analyzed using a random effects model for meta-analysis and subgroup analysis. RESULTS: A total of 955 publications were initially identified in our search and screened; six studies were eventually included in the analysis. The average age of study participants was 60.3 ± 12.6 years and 65.5% were men. There was a high degree of heterogeneity among studies. The results showed that IL-17 level were higher in the case group than those in the control group (standardized mean difference, SMD = 1.60, 95% confidence interval (95% CI): 0.53-2.66, P = 0.003). In sensitivity analysis, the merged results showed good robustness. Additionally, subgroup analysis showed that race and ethnicity, sample size, and detection methods were significant factors influencing heterogeneity in the published studies. CONCLUSION: Our finding revealed that increased IL-17 level contributed to the development of ICVD, suggesting IL-17 as a potential risk marker. Further research is needed to establish IL-17 as a therapeutic biomarker of ICVD.


Asunto(s)
Biomarcadores , Interleucina-17 , Isquemia Miocárdica , Humanos , Interleucina-17/sangre , Masculino , Femenino , Persona de Mediana Edad , Anciano , Isquemia Miocárdica/sangre , Isquemia Miocárdica/inmunología , Isquemia Miocárdica/diagnóstico , Isquemia Miocárdica/epidemiología , Medición de Riesgo , Biomarcadores/sangre , Regulación hacia Arriba , Factores de Riesgo , Pronóstico
15.
Radiat Res ; 201(4): 294-303, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38588381

RESUMEN

Radiation-induced intestinal damage (RIID) is a common side effect of radiotherapy in patients with abdominopelvic malignancies. Gap junctions are special structures consisting of connexins (Cxs). This study aimed to investigate the expression and role of connexins in RIID and underlying mechanism. In this study, a calcein-AM fluorescence probe was used to detect changes in gap junctional intercellular communication in intestinal epithelial IEC-6 cells. Our results show that gap junctional intercellular communication of IEC-6 cells was reduced at 6, 12, 24, and 48 h after irradiation, with the most pronounced effect at 24 h. Western blotting and immunofluorescence results showed that the expression of Cx43, but not other connexins, was reduced in irradiated intestinal epithelial cells. Silencing of Cx43 reduced gap junctional intercellular communication between irradiated intestinal epithelial cells with increased ROS and intracellular Ca2+ levels. Furthermore, knockdown of Cx43 reduced the number of clonal clusters, decreased cell proliferation with increased cytotoxicity and apoptosis. Western blotting results showed that silencing of Cx43 resulted in changed γ-H2AX and PI3K/AKT pathway proteins in irradiated intestinal epithelial cells. Administration of the PI3K/AKT pathway inhibitor LY294002 inhibited the radioprotective effects in Cx43-overexpressing intestinal epithelial cells. Our study demonstrated that Cx43 expression is decreased by ionizing radiation, which facilitates the radioprotection of intestinal epithelial cells.


Asunto(s)
Conexina 43 , Proteínas Proto-Oncogénicas c-akt , Humanos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Calcio/metabolismo , Conexinas/metabolismo , Conexinas/farmacología , Transducción de Señal , Uniones Comunicantes , Comunicación Celular
16.
BMC Cardiovasc Disord ; 24(1): 197, 2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38580957

RESUMEN

BACKGROUND: Heart failure (HF) is a heterogeneous syndrome that affects millions worldwide, resulting in substantial health and economic burdens. However, the molecular mechanism of HF pathogenesis remains unclear. METHODS: HF-related key genes were screened by a bioinformatics approach.The impacts of HAPLN1 knockdown on Angiotensin II (Ang II)-induced AC16 cells were assessed through a series of cell function experiments. Enzyme-linked immunosorbent assay (ELISA) was used to measure levels of oxidative stress and apoptosis-related factors. The HF rat model was induced by subcutaneous injection isoprenaline and histopathologic changes in the cardiac tissue were assessed by hematoxylin and eosin (HE) staining and echocardiographic index. Downstream pathways regulated by HAPLN1 was predicted through bioinformatics and then confirmed in vivo and in vitro by western blot. RESULTS: Six hub genes were screened, of which HAPLN1, FMOD, NPPB, NPPA, and COMP were overexpressed, whereas NPPC was downregulated in HF. Further research found that silencing HAPLN1 promoted cell viability and reduced apoptosis in Ang II-induced AC16 cells. HAPLN1 knockdown promoted left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS), while decreasing left ventricular end-systolic volume (LVESV) in the HF rat model. HAPLN1 knockdown promoted the levels of GSH and suppressed the levels of MDA, LDH, TNF-α, and IL-6. Mechanistically, silencing HAPLN1 activated the PKA pathway, which were confirmed both in vivo and in vitro. CONCLUSION: HAPLN1 knockdown inhibited the progression of HF by activating the PKA pathway, which may provide novel perspectives on the management of HF.


Asunto(s)
Proteínas de la Matriz Extracelular , Insuficiencia Cardíaca , Función Ventricular Izquierda , Animales , Ratas , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/metabolismo , Ratas Sprague-Dawley , Transducción de Señal , Volumen Sistólico , Proteoglicanos/genética , Proteoglicanos/metabolismo , Proteínas de la Matriz Extracelular/genética , Proteínas de la Matriz Extracelular/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo
17.
Biochem Genet ; 2024 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-38613717

RESUMEN

Drug resistance is the major difficulty in treatment of lung squamous cell carcinoma (LUSC). This study aims to explore drug response-related miRNAs (DRmiRNAs) based on multi-omics research. We identified DRmiRNAs of LUSC with a multi-omics integrated system that combines expression data of microRNA, lncRNA, mRNA, methylation levels, somatic mutations. After identifying DRmiRNAs, we screened and validated of the target mRNAs of DRmiRNAs through Targetscan and the miRDB database. Then, Real-time PCR and Western blot assays were used to estimate the expression of DRmiRNAs and target protein, and the dual-luciferase assays were used to confirm the interaction of DRmiRNAs and target mRNA. Furthermore, CCK-8 (Cell Counting Kit-8) assays were used to evaluate cell proliferation and drug sensitivity. After integrated analysis, hsa-miR-185-5p was identified as DRmiRNA based on multi-omics data. Through Targetscan and miRDB database, the possible target mRNAs were obtained and PCDHA11 was validated as a target mRNA of miR-185-5p by real-time PCR, Western blot assays and dual-luciferase assays. CCK-8 assays and clone formation assays showed that the proliferation of miR-185-5p mimics was significantly slower than that of miR-185-5p inhibitors, which means overexpression of miR-185-5p enhanced the anticancer effects of cisplatin, whereas the downregulation of miR-185-5p reduced the effects. Furthermore, the proliferation of silencing PCDHA11 was significantly slower than that of overexpression of PCDHA11, which means PCDHA11 overexpression weakened the anticancer effects of cisplatin, and silencing PCDHA11 enhanced the effects. This study demonstrated that miR-185-5p was involved in chemoresistance of LUSC cells to cisplatin partly via down-regulating PCDHA11, which may promote understanding the underlying molecular mechanisms of drug response.

18.
Nature ; 629(8012): 597-602, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38658762

RESUMEN

Hydroformylation is an industrial process for the production of aldehydes from alkenes1,2. Regioselective hydroformylation of propene to high-value n-butanal is particularly important, owing to a wide range of bulk applications of n-butanal in the manufacture of various necessities in human daily life3. Supported rhodium (Rh) hydroformylation catalysts, which often excel in catalyst recyclability, ease of separation and adaptability for continuous-flow processes, have been greatly exploited4. Nonetheless, they usually consist of rotationally flexible and sterically unconstrained Rh hydride dicarbonyl centres, only affording limited regioselectivity to n-butanal5-8. Here we show that proper encapsulation of Rh species comprising Rh(I)-gem-dicarbonyl centres within a MEL zeolite framework allows the breaking of the above model. The optimized catalyst exhibits more than 99% regioselectivity to n-butanal and more than 99% selectivity to aldehydes at a product formation turnover frequency (TOF) of 6,500 h-1, surpassing the performance of all heterogeneous and most homogeneous catalysts developed so far. Our comprehensive studies show that the zeolite framework can act as a scaffold to steer the reaction pathway of the intermediates confined in the space between the zeolite framework and Rh centres towards the exclusive formation of n-butanal.

19.
Chemosphere ; 357: 142057, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38636920

RESUMEN

Recent leaks of underground fuel storage tanks in the Pearl Harbor region have led to direct release of un-weathered petroleum hydrocarbons (PHCs) into drinking water sources, which then directly underwent chlorination disinfection treatment. Since the control of disinfection byproducts (DBPs) traditionally focuses natural organic matters (NOM) from source water and little is known about the interactions between free chlorine and un-weathered PHCs, laboratory chlorination experiments in batch reactors were conducted to determine the formation potential of DBPs during chlorination of PHC-contaminated drinking water. Quantitative analysis of regulated DBPs showed that significant quantities of THM4 (average 3,498 µg/L) and HAA5 (average 355.4 µg/L) compounds were formed as the result of chlorination of un-weathered PHCs. Amongst the regulated DBPs, THM4, which were comprised primarily of chloroform and bromodichloromethane, were more abundant than HAA5. Numerous unregulated DBPs and a large diversity of unidentified potentially halogenated organic compounds were also produced, with the most abundant being 1,1-dichloroacetone, 1,2-dibromo-3-chloropropane, chloropicrin, dichloroacetonitrile, and trichloracetonitrile. Together, the results demonstrated the DBP formation potential when PHC-contaminated water undergoes chlorination treatment. Further studies are needed to confirm the regulated DBP production and health risks under field relevant conditions.


Asunto(s)
Desinfección , Agua Potable , Halogenación , Hidrocarburos , Petróleo , Contaminantes Químicos del Agua , Purificación del Agua , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Agua Potable/química , Purificación del Agua/métodos , Petróleo/análisis , Hidrocarburos/análisis , Desinfectantes/análisis , Desinfectantes/química , Cloro/química , Trihalometanos/análisis , Trihalometanos/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...