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1.
Oncol Lett ; 28(3): 416, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38988443

RESUMEN

Transforming growth factor-ß (TGF-ß) signaling pathway serves a pivotal role in the pathogenesis of colorectal cancer (CRC). However, the specific molecular mechanisms by which the TGF-ß signaling pathway regulates CRC are still not fully understood. In the present study, metabolomics and transcriptomics were used to screen for key metabolites and regulatory genes most related to the regulation of the TGF-ß signaling pathway in CRC. Additionally, reverse transcription-quantitative PCR, western blotting and Transwell assays were performed to assess the process of epithelial-mesenchymal transition (EMT). Metabolomics analysis indicated that TGF-ß1 has an impact on purine metabolism, leading to an increase in the purine metabolite inosine. The increase of inosine is essential for facilitating EMT and cell migration in CRC cells. Furthermore, the integrated analysis of metabolomics and transcriptomics data revealed that TGF-ß1 induces the expression of laccase domain-containing 1 (LACC1), an enzyme involved in the regulation of inosine. Knockdown of LACC1 resulted in a reduction of TGF-ß1-induced alterations in inosine levels, EMT and cell migration in CRC cells. The results of the present study suggest that the TGF-ß signaling pathway is involved in the regulation of purine metabolism in CRC through the modulation of LACC1 expression. Furthermore, LACC1 appears to influence EMT and cell migration by elevating the levels of the purine metabolite inosine.

2.
J Formos Med Assoc ; 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38991898

RESUMEN

The COVID-19 pandemic remains challenging due to the rapid evolution of the severe acute respiratory syndrome coronavirus 2. This article discusses recent findings on high-risk groups for COVID-19 mortality and morbidity, along with consensus statements from the 2023 Taiwan Association of Gerontology and Geriatrics (TAGG) meeting. It examines evidence on viral mutation mechanisms, emerging variants, and their implications for vaccination strategies. The article underscores advanced age, immunocompromised status, chronic medical conditions, occupational exposure, and socioeconomic disparities as significant risk factors for severe COVID-19 outcomes. TAGG's consensus emphasizes robust vaccination promotion, prioritizing elderly, and immunocompromised groups, individualized multi-dose regimens for immunocompromised patients, and simplified clinical guidelines. Discussions on global and regional recommendations for regular, variant-adapted boosters highlight the non-seasonal nature of COVID-19. Key agreements include escalating domestic preparedness, implementing vigorous risk-based vaccination, and adapting global guidelines to local contexts. Given ongoing viral evolution, proactive adjustment of vaccination policies is essential. Scientific consensus, tailored recommendations, and rapid knowledge dissemination are vital for optimizing COVID-19 protection among vulnerable groups in Taiwan. This article seeks to inform clinical practice and public health policy by summarizing expert-driven vaccination perspectives.

3.
Pain Pract ; 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38951955

RESUMEN

BACKGROUND: Herniated intervertebral disc (HIVD) with radiculopathy is a common degenerative spine disorder. Transforaminal epidural steroid injection (TFESI) is one of the pain relief treatments for lumbar radiculopathy recommended by evidence-based guidelines. Adequate contrast distribution is correlated with better pain control, but the best approach has not been confirmed yet. AIM: To confirm the distribution of contrast medium injected with a new approach of TFESI, that is, far lateral lateral recess approach (FLLR-TFESI). METHODS: Patients receiving TFESI due to HIVD with radiculopathy between 2010 January and 2020 August were retrospectively enrolled. While the FLLR-TFESI was taken as the experimental group, the conventional approach was viewed as the control group. The baseline characteristics, the pattern of contrast enhancement under fluoroscopic guidance, and the complications of these patients were collected and analyzed. RESULTS: A total of 380 patients were analyzed (143 in control group and 237 in experimental group). The two groups were balanced in most baseline characteristics, except disc extrusion (p = 0.01) and scoliosis (p = 0.04). The FLLR-TFESI have a better contrast distribution (p < 0.01), even after adjustment (p < 0.001). No intrathecal injection was noted, but higher rate of intra-disc injection was noted in FLLR-TFESI group (10% vs. 3%, p = 0.008). CONCLUSION: The FLLR-TFESI has a superior contrast enhancement and distribution in comparison to conventional approach. Prospective study to confirm the study result as well as the clinical benefits is suggested in the future.

5.
Synth Syst Biotechnol ; 9(4): 759-765, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-39007090

RESUMEN

Pichia pastoris, a methylotrophic yeast, can utilize methanol as a carbon source and energy source to synthesize high-value chemicals, and is an ideal host for biomanufacturing. Constructing the P. pastoris cell factory is somewhat impeded due to the absence of genetic tools for manipulating multi-gene biosynthetic pathways. To broaden its application in the field of metabolic engineering, this study identified and screened 15 novel integration sites in P. pastoris using CRISPR-Cpf1 genome editing technology, with EGFP serving the reporter protein. These integration sites have integration efficiencies of 10-100 % and varying expression strengths, which allow for selection based on the expression levels of genes as needed. Additionally, these integrated sites are applied in the heterologous biosynthesis of P. pastoris, such as the astaxanthin biosynthetic pathway and the carbon dioxide fixation pathway of the Calvin-Benson-Bassham (CBB) cycle. During the three-site integration process, the 8 genes of the CBB cycle were integrated into the genome of P. pastoris. This indicates the potential of these integration sites for integrating large fragments and suggests their successful application in metabolic engineering of P. pastoris. This may lead to improved efficiency of genetic engineering in P. pastoris.

6.
Mater Horiz ; 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39012046

RESUMEN

The continuous advancement in energy storage technologies necessitates the iteration of energy storage dielectrics urgently. However, the current state-of-the-art composite films fail to meet the application requirements of energy storage devices, which demand a combination of high discharged energy density (Ue), high energy storage efficiency (η), and excellent high-temperature performance. To address this challenge, we present an innovative interlayer composed of pure BN nanosheets in polyetherimide (PEI)-based asymmetrical multilayered composites doped with Na0.5Bi0.5TiO3 ceramic fibers. This innovative structure confers the PEI-based composites upon synergistic optimization of polarization intensity, breakdown strength and energy loss by designed interface effectiveness adopting tailored filler and interface configuration as modulation means, which can be further confirmed by finite element simulations and comparative experiments. The resultant composite film achieves an excellent Ue of 22.95 J cm-3 and an ultra-high η of 96.81% at ambient temperature, along with high-temperature performances of 12.88 J cm-3 and 79.26% at 150 °C, surpassing all previously reported polymer films in terms of both metrics. This study provides new insights for developing high-performance energy storage dielectrics suitable for practical applications.

7.
Heliyon ; 10(12): e32952, 2024 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-38994119

RESUMEN

Sensorineural hearing loss (SNHL) is a prevalent condition in otolaryngology. A key obstacle is finding effective strategies for regenerating damaged cochlear hair cells in adult animals. A practical and reliable approach has been developed to create a superior cell source for stem cell transplantation in the inner ear to treat SNHL. Atoh1 is involved in the differentiation of neurons, intestinal secretory cells, and mechanoreceptors including auditory hair cells, and thus plays an important role in neurogenesis. Lentivirus-mediated transfection of bone marrow mesenchymal stem cells (BMSCs) was utilized to achieve stable expression of the essential transcription factor Atoh1, which is crucial for developing auditory hair cells without compromising cell survival. By manipulating the induction conditions through altering the cell growth environment using anti-adherent culture, the synergistic impact of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) was effectively applied to significantly improve the differentiation efficiency of bone marrow-derived mesenchymal stem cells (BMSC) into neural stem cells (NSCs) following Atoh1 transfection, thereby reducing the induction time. The study indicated that the newly proposed transdifferentiation method effectively transformed BMSCs into NSCs in a controlled environment, presenting a potential approach for stem cell transplantation to promote hair cell regeneration.

8.
Environ Int ; 190: 108876, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-39002330

RESUMEN

BACKGROUND: Air pollution is recognized as a modifiable risk factor for dementia, and recent evidence suggests that improving air quality could attenuate cognitive decline and reduce dementia risk. However, studies have yet to explore the effects of improved air quality on brain structures. This study aims to investigate the impact of air pollution reduction on cognitive functions and structural brain differences among cognitively normal older adults. METHODS: Four hundred and thirty-one cognitively normal older adults were from the Epidemiology of Mild Cognitive Impairment study in Taiwan (EMCIT), a community-based cohort of adults aged 60 and older, between year 2017- 2021. Annual concentrations of PM2.5, NO2, O3, and PM10 at participants' residential addresses during the 10 years before enrollment were estimated using ensemble mixed spatial models. The yearly rate of change (slope) in air pollutants was estimated for each participant. Cognitive functions and structural brain images were collected during enrollment. The relationships between the rate of air pollution change and cognitive functions were examined using linear regression models. For air pollutants with significant findings in relation to cognitive function, we further explored the association with brain structure. RESULTS: Overall, all pollutant concentrations, except O3, decreased over the 10-year period. The yearly rates of change (slopes) in PM2.5 and NO2 were correlated with better attention (PM2.5: r = -0.1, p = 0.047; NO2: r = -0.1, p = 0.03) and higher white matter integrity in several brain regions. These regions included anterior thalamic radiation, superior longitudinal fasciculus, inferior longitudinal fasciculus, corticospinal tract, and inferior fronto-occipital fasciculus. CONCLUSIONS: Greater rate of reduction in air pollution was associated with better attention and attention-related white matter integrity. These results provide insight into the mechanism underlying the relationship between air pollution, brain health, and cognitive aging among older adults.

9.
Ground Water ; 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38961724

RESUMEN

Analytical and semi-analytical models for stream depletion with transient stream stage drawdown induced by groundwater pumping are developed to address a deficiency in existing models, namely, the use of a fixed stream stage condition at the stream-aquifer interface. Field data are presented to demonstrate that stream stage drawdown does indeed occur in response to groundwater pumping near aquifer-connected streams. A model that predicts stream depletion with transient stream drawdown is developed based on stream channel mass conservation and finite stream channel storage. The resulting models are shown to reduce to existing fixed-stage models in the limit as stream channel storage becomes infinitely large, and to the confined aquifer flow with a no-flow boundary at the streambed in the limit as stream storage becomes vanishingly small. The model is applied to field measurements of aquifer and stream drawdown, giving estimates of aquifer hydraulic parameters, streambed conductance, and a measure of stream channel storage. The results of the modeling and data analysis presented herein have implications for sustainable groundwater management.

10.
Biomed Environ Sci ; 37(6): 594-606, 2024 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-38988110

RESUMEN

Objective: The effect of the functionally unknown gene C6orf120 on autoimmune hepatitis was investigated on C6orf120 knockout rats ( C6orf120 -/- ) and THP-1 cells. Method: Six-eight-week-old C6orf120 -/- and wild-type (WT) SD rats were injected with Con A (16 mg/kg), and euthanized after 24 h. The sera, livers, and spleens were collected. THP-1 cells and the recombinant protein (rC6ORF120) were used to explore the mechanism in vitro. The frequency of M1 and M2 macrophages was analyzed using flow cytometry. Western blotting and PCR were used to detect macrophage polarization-associated factors. Results: C6orf120 knockout attenuated Con A-induced autoimmune hepatitis. Flow cytometry indicated that the proportion of CD68 +CD86 +M1 macrophages from the liver and spleen in the C6orf120 -/- rats decreased. C6orf120 knockout induced downregulation of CD86 protein and the mRNA levels of related inflammatory factors TNF-α, IL-1ß, and IL-6 in the liver. C6orf120 knockout did not affect the polarization of THP-1 cells. However, rC6ORF120 promoted the THP-1 cells toward CD68 +CD80 +M1 macrophages and inhibited the CD68 +CD206 +M2 phenotype. Conclusion: C6orf120 knockout alleviates Con A-induced autoimmune hepatitis by inhibiting macrophage polarization toward M1 macrophages and reducing the expression of related inflammatory factors in C6orf120 -/- rats.


Asunto(s)
Concanavalina A , Hepatitis Autoinmune , Macrófagos , Ratas Sprague-Dawley , Animales , Macrófagos/efectos de los fármacos , Hepatitis Autoinmune/inmunología , Hepatitis Autoinmune/genética , Ratas , Concanavalina A/toxicidad , Humanos , Masculino , Técnicas de Inactivación de Genes , Células THP-1
11.
Poult Sci ; 103(9): 104024, 2024 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-39013296

RESUMEN

Toxoplasma gondii (T. gondii) is an intracellular protozoan that can cause toxoplasmosis in all warm-blooded hosts. This study focused on the prevalence and genetic characterize of T. gondii in ducks from Fujian province, China. Genomic DNA was extracted from duck tissue samples (heart, liver, lung, and muscle). To assess the genetic diversity of the T. gondii isolates, it was determined by using multilocus polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. A total of 586 ducks from 5 cities in Fujian province were tested, and 35 (6.0%) of which were found to be positive for the T. gondii B1 gene. Further genotyping of these positive samples at 10 genetic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) using PCR-RFLP revealed that one tissue samples (heart samples from Fuzhou ducks) were identified as Type I (ToxoDB#10). This study is the first report on the prevalence and genetic characterization of T. gondii in ducks in Fujian province, and Type I (ToxoDB#10) is found in ducks in China for the first time. The findings document the genetic characterization of T. gondii in free-range ducks from Fujian Province, thereby enriching the understanding of T. gondii genetic diversity in China. Moreover, these results provide essential data support for further prospective studies and underscores the "One Health" concept, emphasizing the integral link among human, animal, and environmental health.

12.
Dev Dyn ; 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38822685

RESUMEN

BACKGROUND: Approximately 7% of the males exhibit reduced fertility; however, the regulatory genes and pathways involved remain largely unknown. TBC1 domain family member 21 (TBC1D21) contains a conserved RabGAP catalytic domain that induces GDP/GTP exchange to inactivate Rabs by interacting with microtubules. We previously reported that Tbc1d21-null mice exhibit severe sperm tail defects with a disrupted axoneme, and that TBC1D21 interacts with RAB10. However, the pathological mechanisms underlying the Tbc1d21 loss-induced sperm tail defects remain unknown. RESULTS: Murine sperm from wild-type and Tbc1d21-null mice were comparatively analyzed using proteomic assays. Over 1600 proteins were identified, of which 15 were significantly up-regulated in Tbc1d21-null sperm. Notably, several tektin (TEKT) family proteins, belonging to a type of intermediate filament critical for stabilizing the microtubular structure of cilia and flagella, were significantly up-regulated in Tbc1d21-/- sperm. We also found that TBC1D21 interacts with TEKT1. In addition, TEKT1 co-localized with RAB10 during sperm tail formation. Finally, we found Tbc1d21-null sperm exhibited abnormal accumulation of TEKT1 in the midpiece region, accompanied by disrupted axonemal structures. CONCLUSIONS: These results reveal that TBC1D21 modulates TEKTs protein localization in the axonemal transport system during sperm tail formation.

13.
Front Med (Lausanne) ; 11: 1373726, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38846140

RESUMEN

Objective: As patient life expectancy has increased and people are living longer than before, the rate of mechanical ventilation among elderly patients in the intensive care unit has increased. Older patients who receive mechanical ventilation and have multiple comorbidities are more likely to have a do not resuscitate order than are younger patients with fewer comorbidities. The aim of our study was to describe the patient characteristics and predictive factors of do not resuscitate orders during hospitalization among elderly patients who received ventilation in the intensive care unit. Methods: This was a retrospective review of the electronic medical records of patients in the intensive care unit of a teaching hospital in southern Taiwan. We enrolled patients admitted to the general intensive care unit from January 1, 2018, to September 31, 2020, and patients older than 80 years who experienced respiratory failure, were intubated and received mechanical ventilation. We analyzed patient demographics, disease severity during hospitalization and comorbidities. If a patient had multiple admissions to the intensive care unit, only the first admission was recorded. Results: Of the 305 patients over 80 years of age with respiratory failure who were intubated and placed on a ventilator, 66 were excluded because of incomplete data, and 13 were excluded because they had already signed a do not resuscitate order prior to admission to the hospital. Ultimately, 226 patients were included in this study. A higher acute physiology and chronic health evaluation II score (>30) was also associated with an increased likelihood of a do not resuscitate order (odds ratio (OR) = 3.85, 95% CI = 1.09-13.62, p = 0.0362). Patients who had acute kidney injury or cerebrovascular accident were more likely to have a do not resuscitate order (OR = 2.74, 95% CI = 1.03-7.28, p = 0.0428 and OR = 7.32, 95% CI = 2.02-26.49, p = 0.0024, respectively). Conclusion: Our study showed that older age, greater disease severity, and certain critical interventions were associated with a greater propensity for do not resuscitate orders, which is crucial for understanding patient preferences and guiding end-of-life care discussions. These findings highlight the importance of clinical severity and specific health events in predicting end-of-life care preferences in older patient groups.

14.
Plast Reconstr Surg Glob Open ; 12(6): e5872, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38841535

RESUMEN

Background: Head and neck lymphedema (HNL), including external and internal types, could be a possible consequence for patients who have received neck dissection and radiotherapy for head and neck cancer. Initially, the common presentations are heaviness or tightness, followed by swelling in appearance, or difficulty speaking and swallowing in internal edema cases. Lymphovenous anastomosis (LVA) is an established approach to treat extremity lymphedema. We hereby present our preliminary experience in using LVA to treat HNL. Methods: Between March 2021 and January 2024, six patients with HNL were treated with LVA via a preauricular or submandibular incision of the obstructed side. Lymphedema Symptom Intensity and Distress Surveys-Head and Neck (LSIDS-H&N) were used for evaluation. In addition, for the external type, MD Anderson Cancer Center Head and Neck Lymphedema (MDACC HNL) rating scale was used for evaluation. For the internal type, Swallowing Quality of Life was used for evaluation. Results: With an average follow-up period of 15.4 ±â€…15.9 months, LSIDS-H&N improved from 1.11 ±â€…0.54 to 0.44 ±â€…0.66 (P = 0.02). For patients with the external type, within an average follow-up period of 15 ±â€…16.1 months, the MDACC HNL rating scale improved from level 2 to 0 or 1a (P = 0.008). For patients with the internal type, within an average follow-up period of 21 ±â€…17.3 months, Swallowing Quality of Life improved from 130.5 ±â€…9.2 to 151 ±â€…19.8 (P = 0.5). Conclusions: Based on our preliminary results, LVA could be a potential solution to both external and internal HNL.

15.
Molecules ; 29(12)2024 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-38930928

RESUMEN

A mild, efficient and practical protocol for the preparation of 2-sulfonylquinolines through CS2/Et2NH-induced deoxygenative C2-H sulfonylation of quinoline N-oxides with readily available RSO2Cl was developed. The reaction proceeded well under transition-metal-free conditions and exhibited a wide substrate scope and functional group tolerance. The preliminary studies suggested that the nucleophilic sulfonyl sources were generated in situ via the reaction of CS2, Et2NH and sulfonyl chlorides.

16.
J Org Chem ; 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38935753

RESUMEN

A series of amides, including α-bromo hydroxamates, N-alkoxyamides, and N-aryloxyamides, were subjected to phosphine-catalyzed ring-opening O-selective addition with cyclopropenones, producing various special α,ß-unsaturated esters containing oxime ether motif, in moderate to excellent yields, with high regioselectivity, and exclusive O-selectivity. The methodology is highly atom-economical, with simple operation procedures, and compatible with a wide substrate scope (more than 44 examples).

17.
Front Immunol ; 15: 1404812, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38938564

RESUMEN

Background: The therapeutic effectiveness of immune checkpoint inhibitors (ICIs) in bladder cancer varies among individuals. Identifying reliable predictors of response to these therapies is crucial for optimizing patient outcomes. Methods: This retrospective study analyzed 348 bladder cancer patients treated with ICIs, with additional validation using data from 248 patients at our institution who underwent PD-L1 immunohistochemical staining. We examined patient smoking history, clinicopathological characteristics, and immune phenotypes. The main focus was the correlation between smoking history and immunotherapy outcomes. Multivariate logistic and Cox proportional hazard regressions were used to adjust for confounders. Results: The study cohort comprised 348 bladder cancer patients receiving ICIs. Among them, 116 (33.3%) were never smokers, 197 (56.6%) were former smokers (median pack-years = 28), and 35 (10.1%) were current smokers (median pack-years = 40). Analysis revealed no statistically significant difference in overall survival across different smoking statuses (objective response rates were 11.4% for current smokers, 17.2% for never smokers, and 22.3% for former smokers; P = 0.142, 0.410, and 0.281, respectively). However, a notable trend indicated a potentially better response to immunotherapy in former smokers compared to current and never smokers. In the validation cohort of 248 patients from our institution, immunohistochemical analysis showed that PD-L1 expression was significantly higher in former smokers (55%) compared to current smokers (37%) and never smokers (47%). This observation underscores the potential influence of smoking history on the tumor microenvironment and its responsiveness to ICIs. Conclusion: In conclusion, our study demonstrates the importance of incorporating smoking history in predicting the response to immunotherapy in bladder cancer patients, highlighting its role in personalized cancer treatment approaches. Further research is suggested to explore the comprehensive impact of lifestyle factors on treatment outcomes.


Asunto(s)
Inhibidores de Puntos de Control Inmunológico , Inmunoterapia , Fumar , Neoplasias de la Vejiga Urinaria , Humanos , Neoplasias de la Vejiga Urinaria/terapia , Neoplasias de la Vejiga Urinaria/inmunología , Neoplasias de la Vejiga Urinaria/mortalidad , Masculino , Femenino , Anciano , Persona de Mediana Edad , Estudios Retrospectivos , Fumar/efectos adversos , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Inmunoterapia/métodos , Resultado del Tratamiento , Antígeno B7-H1/metabolismo , Anciano de 80 o más Años , Adulto
18.
Front Plant Sci ; 15: 1396309, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38938638

RESUMEN

Chlorophyll a fluorescence, a sensitive and cost-effective probe, is widely used in photosynthetic research. Its rapid phase, occurring within 1 second under intense illumination, displays complex O-J-I-P transients, providing valuable insights into various aspects of photosynthesis. In addition to employing experimental approaches to measure the rapid Fluorescence Induction (FI) kinetics, mathematical modeling serves as a crucial tool for understanding the underlying mechanisms that drive FI dynamics. However, the significant uncertainty and arbitrary nature of selecting model parameters amplify concerns about the effectiveness of modeling tools in aiding photosynthesis research. Therefore, there is a need to gain a deeper understanding of how these models operate and how arbitrary parameter choices may influence their outcomes. In this study, we employed the Morris method, a global Sensitivity Analysis (SA) tool, to assess the significance of rate constants employed in an existing fluorescence model, particularly those linked to the entire electron transport chain, in shaping the rapid FI dynamics. In summary, utilizing the insights gained from the Morris SA allows for targeted refinement of the photosynthesis model, thereby improving our understanding of the complex processes inherent in photosynthetic systems.

19.
Chem Asian J ; : e202400697, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38941239

RESUMEN

Novel D-A1-A2-π-A organic sensitizers (FZ-sensitizer), utilizing spiro[fluorene-9,9'-phenanthren]-10'-one (A1) and benzo[c][1,2,5]thiadiazole(A2) moiety as two auxiliary acceptors, are synthesized and applied in dye-sensitized solar cells (DSSCs) and hydrogen production. By incorporating a bulky A1 and A2 between the donor (D) and π-bridge moiety, structural modifications inhibit molecular aggregation, while the carbonyl group enhances the capture of Li+ ions, thereby delaying charge recombination. Furthermore, the extended π-conjugation broadens the light absorption range and enhances the power conversion efficiency (PCE) of FZ-2 under AM1.5 conditions, achieving up to 5.72%. Co-sensitization with N719 and FZ-2 shows PCE of 9.60% under one sun. Under TL84 indoor light conditions, the efficiency is 29.69% at 2500 lux. FZ-sensitizers also exhibit high efficiency in photocatalytic hydrogen production. The hydrogen production activities of FZ-2 are 9190 µmol/g (1 hour) and 76582 µmol/g (12 hours) respectively, while those of FZ-1 are 7430 µmol/g (1 hour) and 64004 µmol/g (12 hours), indicating that FZ-2 can inject charges into TiO2 more efficiently and utilize them for water splitting. Stability testing of photocatalytic water splitting after 12 hours shows a turnover number (TON) of 4249 for FZ-1 and 5378 for FZ-2.

20.
Org Lett ; 26(25): 5237-5242, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38856036

RESUMEN

Brevitaxin was prepared in nine steps from commercially available carnosic acid. The construction of the 1,4-benzodioxin moiety involved an unique stepwise ortho-quinone-engaged [4+2] cycloaddition. Two strategic stages were employed to prepare the highly unsaturated cycloaddition precursor 3: (1) synthesizing the diene moiety (C1-C2 and C10-C20 double bonds) by regioselective ortho-quinone tautomerization, and (2) installing four sp2-hybridized carbon atoms (C3, C5, C6 and C7) in one step using a SeO2-promoted chemo- and regioselective oxidation reaction.

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