Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 256
Filtrar
2.
BMC Ophthalmol ; 24(1): 158, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38600456

RESUMO

BACKGROUND: This study aimed to compare the visual outcomes of the first operated eyes with those of the second operated eyes following small-incision lenticule extraction (SMILE). METHODS: A total of 202 patients (404 eyes) underwent SMILE using the tear film mark centration method for myopia and myopic astigmatism correction. Baseline characteristics, objective optical quality, decentered displacement, induced corneal aberrations, and modulation transfer function (MTF) values were assessed. Linear regression analyzed the relationship between decentration and visual quality parameters, including corneal aberrations and MTF values. RESULTS: No significant difference was observed in objective visual quality, efficacy, and safety indexes between the two groups (all P > 0.05). The average decentered displacement for the first and second surgical eyes was 0.278 ± 0.17 mm and 0.315 ± 0.15 mm, respectively (P = 0.002). The horizontal coma in the first surgical eyes were notably lower than in the second (P = 0.000). MTF values at spatial frequencies of 5, 10, 15, and 20 cycles/degree (c/d) were higher in the first surgical eyes compared to the second (all P < 0.05). Linear regression indicated that high-order aberrations (HOAs), root mean square (RMS) coma, spherical aberration, horizontal coma, vertical coma, and eccentric displacement were all linearly correlated. Furthermore, MTF values exhibited a linear relationship with eccentric displacement across these spatial frequencies. CONCLUSIONS: There was no discernible difference in visual acuity, efficacy, or safety between the two operated eyes. Nonetheless, the first operated eyes exhibited reduced decentered displacement and demonstrated superior outcomes in terms of horizontal coma and MTF values compared to the second operated eyes following SMILE. The variations in visual quality parameters were linearly correlated with decentered displacement.


Assuntos
Astigmatismo , Aberrações de Frente de Onda da Córnea , Miopia , Humanos , Refração Ocular , Coma , Topografia da Córnea , Lasers de Excimer/uso terapêutico , Miopia/cirurgia , Astigmatismo/cirurgia , Substância Própria/cirurgia
3.
J Immunother ; 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38630910

RESUMO

SUMMARY: Taurine (Tau) has been found to inhibit triple-negative breast cancer (TNBC) invasion and metastasis. However, its effect on tumor-promoting macrophages and tumor suppressor macrophages in breast cancer progression remains unknown. In this study, we investigated the effects of Tau on macrophage polarization and its role in TNBC cell growth, invasion, and metastasis. We induced human THP-1 monocytes to differentiate into M2 macrophages through exogenous addition of interleukin-4. We used the TNBC cell lines MDA-MB-231 and BT-549 cultured in a conditioned medium from M2 macrophages to investigate the effect of Tau on tumor growth and invasion. We analyzed macrophage subset distribution, M1 and M2 macrophage-associated markers, and mRNA expression by quantitative polymerase chain reaction. We also detected the PTEN-PI3K/Akt/mTOR signaling pathway that mediates M1 macrophage to suppress tumor invasion using western blotting. Our results showed that Tau inhibits breast cancer metastasis to the lungs in vivo and cell invasion by altering the polarization of tumor-associated macrophage in vitro. In addition, Tau can up-regulate PTEN expression, suppress the PI3K-Akt signaling pathway, and promote the M1 polarization of macrophages, which ultimately inhibits the metastasis of TNBC cells. Our findings suggest that Tau inhibits the activation of the PI3K-Akt-mTOR signaling pathway by up-regulating PTEN, promotes the proportion of M1 macrophages in tumor-associated macrophage, and suppresses the invasion and metastasis of TNBC. This provides a potential therapeutic approach to influence cancer progression and metastasis.

4.
Biol Trace Elem Res ; 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589681

RESUMO

Cadmium (Cd) and lead (Pb) are heavy metals prevalent in the environment and feed, and they reduce production performance of domestic animals, as well as they result in residue in animal tissues. The kidney is the target tissue for Cd and Pb. And the kidney is crucial for the reabsorption of calcium (Ca), which consequently influences bone strength. However, there are relatively few studies related to the effects of Cd and Pb exposure on performance, bone strength and kidney damage in livestock. The purpose of this experiment was to explore the combined effect of Cd and Pb on growth performance and renal impairment and the possible underlying mechanism. For this, 168 1-day-old Ross 308 broilers were randomly divided into four groups of six birds each, with seven replicates in each group: control group, 50 mg Cd/kg body weight group, 200 mg Pb/kg body weight group and 50 mg Cd/kg body weight + 200 mg Pb/kg body weight group. Feed intake was recorded daily and body weight was recorded weekly. The results show that at the end of the 3rd and 6th week, one broiler from each replicate was randomly selected for sampling. Boilers co-exposed to Cd and Pb for 3 weeks and 6 weeks had significantly decreased average daily feed intake (ADFI) and average daily body weight gain (ADG) than the control group, and the ratio of feed-to-weight gain (F/G) significantly increased after 6 weeks of co-exposure to Cd and Pb. Microscopic picture and ultrastructure analyses of the kidneys showed that Cd and Pb caused kidney damage to broiler chickens, and the damage was more serious in the Cd + Pb group, which was manifested by increased renal tubular epithelial degeneration and increased interstitial stasis points. Dietary exposure to Cd and Pb impaired production performance and induced renal oxidative damage in broilers. The combined effects of Cd and Pb on the kidneys are greater than their effects alone. The PERK-ATF4 pathway mediated endoplasmic reticulum stress participates the renal oxidative damage during chronic Cd and Pb exposure.

5.
Water Res ; 256: 121608, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38657310

RESUMO

The application of ozone (O3) disinfection has been hindered by its low solubility in water and the formation of disinfection by-products (DBPs). In this study, capacitive disinfection is applied as a pre-treatment for O3 oxidation, in which manganese dioxide with a rambutan-like hollow spherical structure is used as the electrode to increase the charge density on the electrode surface. When a voltage is applied, the negative-charged microbes are attracted to the electrodes and killed by electrical interactions. The contact between microbes and capacitive electrodes leads to changes in cell permeability and burst of reactive oxygen species, thereby promoting the diffusion of O3 into the cells. After O3 penetrates the cell membrane, it can directly attack the cytoplasmic constituents, accelerating fatal and irreversible damage to pathogens. As a result, the performance of the capacitance-O3 process is proved better than the direct sum of the two individual process efficiencies. The design of capacitance-O3 system is beneficial to reduce the ozone dosage and DBPs with a broader inactivation spectrum, which is conducive to the application of ozone in primary water disinfection.


Assuntos
Desinfecção , Compostos de Manganês , Óxidos , Ozônio , Ozônio/farmacologia , Ozônio/química , Óxidos/farmacologia , Óxidos/química , Desinfecção/métodos , Compostos de Manganês/química , Compostos de Manganês/farmacologia , Membrana Celular/efeitos dos fármacos , Purificação da Água/métodos , Eletrodos , Bactérias/efeitos dos fármacos
6.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 38(4): 448-454, 2024 Apr 15.
Artigo em Chinês | MEDLINE | ID: mdl-38632065

RESUMO

Objective: To compare the early analgesic effects and the impact on knee joint function recovery after unicompartmental knee arthroplasty (UKA) between single adductor canal block (SACB) and continuous adductor canal block (CACB) combined with local infiltration anesthesia (LIA) using a prospective study. Methods: The patients with knee osteoarthritis admitted between April 2022 and December 2023 were enrolled as a subject. Among them, 60 patients met the selection criteria and were enrolled in the study. They were randomly assigned to the SACB group or CACB group in a ratio of 1:1 using a random number table method. There was no significant difference between the two groups ( P>0.05) in terms of age, gender, height, body mass, body mass index, affected side, and preoperative resting visual analogue scale (VAS) score and active VAS score, Oxford knee score (OKS), and American Hospital of Special Surgery (HSS) score. All patients received multimodal analgesia management using LIA combined with SACB or CACB. The operation time, pain related indicators (resting and activity VAS scores, number and timing of breakthrough pain, opioid consumption), joint function related indicators (quadriceps muscle strength, knee range of motion, OKS score, and HSS score), as well as postoperative block complications and adverse events were recorded and compared between the two groups. Results: There was no significant difference in the operation time between the two groups ( P<0.05). All patients in the two groups were followed up with a follow-up time of (9.70±4.93) months in the SACB group and (12.23±5.05) months in the CACB group, and the difference was not significant ( P>0.05). The CACB group had a significant lower resting VAS score at 24 hours after operation compared to the SACB group ( P<0.05). There was no significant difference in resting and active VAS scores between the two groups at other time points ( P>0.05). The CACB group had a significantly lower incidence of breakthrough pain compared to the SACB group [9 cases (30.00%) vs. 17 cases (56.67%); P<0.05). However, there was no significant difference in the timing of breakthrough pain occurrence and opioid consumption between the two groups ( P>0.05). Four cases in the SACB group and 7 cases in the CACB group experienced adverse events, with no significant difference in the incidence of adverse events between the two groups ( P>0.05). The CACB group had significantly better knee joint mobility than the SACB group at 1 and 2 days after operation ( P<0.05). There was no significant difference between the two groups in knee joint mobility on 0 day after operation and quadriceps muscle strength and OKS and HSS scores at different time points ( P>0.05). Conclusion: In UKA, the analgesic effects and knee joint function recovery are similar when compared between LIA combined with SACB and LIA combined with CACB. However, SACB is simpler to perform and can avoid adverse events such as catheter displacement and dislocation. Therefore, SACB may be a better choice.


Assuntos
Artroplastia do Joelho , Dor Irruptiva , Bloqueio Nervoso , Humanos , Analgésicos Opioides , Anestesia Local/efeitos adversos , Artroplastia do Joelho/métodos , Dor Irruptiva/complicações , Bloqueio Nervoso/efeitos adversos , Bloqueio Nervoso/métodos , Dor Pós-Operatória , Complicações Pós-Operatórias , Estudos Prospectivos
7.
Front Chem ; 12: 1361930, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38549838

RESUMO

The CuMgAl-x catalysts derived from hydrotalcite precursors with different Mg/Al molar ratios were synthesized and applied to CO2 hydrogenation to methanol reaction. In this study, the effects of Mg/Al molar ratio on the structure and surface properties of CuMgAl-x catalysts were investigated by XRD, N2 adsorption-desorption, SEM, TEM, H2-TPR, CO2-TPD, XPS, and in situ DRIFTS characterization methods. The results showed that an appropriate Mg/Al molar ratio can enhance the Cu-MgO interaction, increasing the basic sites and obtaining suitable acid sites. The dispersion of active Cu on the CuMgAl-x catalysts can be improved by strong Cu-MgO interaction, which enhances the adsorption capacity of CO2 and makes H2 activation easier, accelerates the conversion of intermediate species CO3 * and HCO3 *to HCOO*, and facilitates further conversion to CH3O* and CH3OH. The strong interaction between Cu and MgO was conducive to the formation of Cu+, which can inhibit the desorption of CO in the reverse water gas shift reaction. The CuMgAl-3 catalyst showed the highest CO2 Conversion rate (14.3%), methanol selectivity (94.5%), and STY of methanol (419.3 g⋅kgcat. -1⋅h-1) at 240°C and 2.5 MPa. The results obtained in this paper can provide a new idea for the design of high-performance catalysts for CO2 hydrogenation to methanol.

8.
Heliyon ; 10(5): e27144, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38449619

RESUMO

The COVID-19 pandemic seriously threatened human survival and development. It has also highlighted the significant correlation between ecological and public health. After three years of the COVID pandemic, Chinese consumers have become more aware of the importance of health. Especially in the Internet era, consumers' purchasing methods and health awareness have been changed. Consumers can buy nutritious and organic foods. To understand the impact of consumer psychology and health beliefs on the willingness to purchase organic food in the post-pandemic period, this study uses organic beef as an example and extracts key variables from three basic theories. The three basic theories include the Health Belief Model (HBM), the Theory of Planned Behavior (TPB), and the Norm Activation Model (NAM), respectively. Specifically, perceived susceptibility and severity are combined to form a health belief variable that can drive organic food purchasing. In contrast, perceived benefit, moral norms, self-efficiency, and controllability are introduced as mediating variables to construct the health driving factors of organic beef purchasing. Structural equation modeling (SEM) and mediation effect tests are used to analyse 539 samples. Meanwhile, paths and mechanisms between health concern and other variables are explored. The results show that health concern is an important driving factor. Health concern can significantly promote the formation of willingness to purchase organic beef. Mediation effect tests suggest that health concern can indirectly affect the willingness to purchase organic beef through perceived benefit, moral norms, and controllability, but the mediation effect of self-efficiency is not significant. This study provides important references for government regulation and certification of organic foods as well as for enterprises'organic food marketing strategies.

9.
Gene ; 907: 148280, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38360123

RESUMO

Orofacial clefts (OFCs) represent the most prevalent congenital craniofacial anomalies, significantly impacting patients' appearance, oral function, and psychological well-being. Among these, non-syndromic OFCs (NSOFCs) are the most predominant type, with the etiology attributed to a combination of genetic and environmental factors. Rare variants of key genes involved in craniofacial development-related signaling pathway are crucial in the occurrence of NSOFCs, and our recent studies have identified PTCH1, a receptor-coding gene in the Hedgehog signaling pathway, as a causative gene for NSOFCs. However, the role of PTCH2, the paralog of PTCH1, in pathogenesis of NSOFCs remains unclear. Here, we perform whole-exome sequencing to explore the genetic basis of 144 sporadic NSOFC patients. We identify five heterozygous variants of PTCH2 in four patients: p.L104P, p.A131G, p.R557H, p.I927S, and p.V978D, with the latter two co-occurring in a single patient. These variants, all proven to be rare through multiple genomic databases, with p.I927S and p.V978D being novel variants and previously unreported. Sequence alignment suggests that these affected amino acids are evolutionarily conserved across vertebrates. Utilizing predictive structural modeling tools such as AlphaFold and SWISS-MODEL, we propose that these variants may disrupt the protein's structure and function. In summary, our findings suggest that PTCH2 may be a novel candidate gene predicted to be associated with NSOFCs, thereby broadening the spectrum of causative genes implicated in the craniofacial anomalies.


Assuntos
Fenda Labial , Fissura Palatina , Receptor Patched-2 , Animais , Humanos , Encéfalo/anormalidades , Fenda Labial/genética , Fissura Palatina/genética , Proteínas Hedgehog/genética , Receptor Patched-2/genética , Transdução de Sinais
10.
Transl Cancer Res ; 13(1): 299-316, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38410218

RESUMO

Background: Head and neck squamous cell carcinoma (HNSCC) is currently the sixth most common cancer worldwide, and its prevalence and recurrence rates are gradually increasing. To study the relationship between HNSCC and cell pyroptosis and provide new treatment options for HNSCC, a prognostic model of pyroptosis-related genes (PRGs) was established to predict the prognosis of patients with HNSCC, and an immune correlation analysis was performed. Methods: A total of 53 PRGs were selected. We comprehensively analyzed the role of these PRGs in HNSCC through multiple omics data-set integration. We then identified two different molecular subtypes and found that changes in multi-layer PRGs were associated with clinicopathological characteristics, prognosis, and tumor microenvironment cell-infiltration characteristics in patients. Next, prognostic models were generated for nine PRGs; that is, cytotoxic T lymphocyte antigen 4 (CTLA4), V-set and immunoglobulin domain containing 4 (VSIG4), heparin-binding-epidermal growth factor (HBEGF), aquaporin-1 (AQP1), sodium channel epithelial 1 subunit delta (SCNN1D), argininosuccinate synthase 1 (ASS1), family with sequence similarity 83 member (FAM83), cyclin dependent kinase inhibitor 2A (CDKN2A), and serine protease inhibitor Kazal 6 (SPINK6). Finally, a risk-score model was constructed, and the Kaplan-Meier method was used to evaluate overall survival. In addition, the immune environment and drug sensitivity were analyzed. Results: This study showed that pyroptosis is closely related to HNSCC. The scores generated by the risk markers based on the new nine PRGs were identified as independent risk factors for predicting HNSCC. The differentially expressed genes between the low- and high-risk groups were further found to be related to the tumor immune cells and pathways. In addition, the risk score was found to be significantly correlated with chemosensitivity. Conclusions: Our comprehensive analysis of PRGs revealed their potential role in the tumor immune microenvironment, clinicopathological characteristics, and prognosis. These findings may improve our understanding of pyroptosis in HNSCC and may provide new ideas for evaluating prognosis and developing more effective immunotherapy strategies.

11.
Int J Cardiol Heart Vasc ; 51: 101359, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38371311

RESUMO

Potent P2Y12 receptor antagonists have been used widely for patients undergoing percutaneous coronary intervention with different results. Benefits from different regimens various between trials. Randomized controlled trials (RCTs) have restrictive inclusion and exclusion criteria; thus, they may limit the generalizability of the findings to a broader population. This study was aimed to comprehensively investigate the outcomes of potent P2Y12 inhibitors in patients undergoing PCI, including RCTs and real-world evidence (RWE) studies. Multiple electronic databases were systemically reviewed and searched on compared potent P2Y12 inhibitors with clopidogrel. The primary efficacy end point was composite ischemic cardiovascular event and primary safety endpoint was major bleeding. Overall estimates of proportions and incidence rates with 95 % confidence intervals (CI) were calculated using fixed-effects models. Total 24 studies (140,986 patients) underwent coronary intervention were included in this meta-analysis, including 18 RCTs and 6 large cohort studies with propensity score matching. The potent P2Y12 inhibitors including cangrelor, prasugrel, and ticagrelor, significantly decreased the risk of composite adverse cardiovascular ischemic events (95 % CI 0.89-0.96, p < 0.001), but increased major bleeding (95 % CI 1.15-1.33, p < 0.001) or any bleeding (95 % CI 1.21-1.33, p < 0.001) compared with Clopidogrel. This meta-analysis merges RCTs and RWE studies and comprehensively evidences newer potent P2Y12 inhibitors are significantly more effective than clopidogrel in reduction of composite adverse thrombotic events, but the incidence of major or any bleeding was higher compared with clopidogrel.

12.
J Intensive Med ; 4(1): 125-132, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38263970

RESUMO

Background: No convenient, inexpensive, and non-invasive screening tools exist to identify pulmonary hypertension (PH) - left heart disease (LHD) patients during the early stages of the disease course. This study investigated whether different methods of lung ultrasound (LUS) could be used for the initial investigation of PH-LHD. Methods: This was a single-center prospective observational study which was performed in the Zigong Fourth People's Hospital. We consecutively enrolled patients with heart failure (HF) admitted to the emergency intensive care unit from January 2018 to May 2020. Transthoracic echocardiography and LUS were performed within 24 h before discharge. We used the Spearman coefficient for correlation analysis between ultrasound scores and pulmonary arterial systolic pressure (PASP). Bland-Altman plots were generated to inspect possible bias, and receiver operating characteristic (ROC) curves were calculated to assess the relationship between ultrasound scores and an intermediate and high echocardiographic probability of PH-LHD. Results: Seventy-one patients were enrolled in this study, with an overall median age of 79 (interquartile range: 71.5-84.0) years. Among the 71 patients, 36 (50.7%) cases were male, and 26 (36.6%) had an intermediate and high echocardiographic probability of PH. All four LUS scores in patients with an intermediate and high probability of PH were significantly higher than in patients with a low probability of PH (P <0.05). The correlation coefficient (r) between different LUS scoring methods and PASP was moderate for the 6-zone (r=0.455, P <0.001), 8-zone (r=0.385, P=0.001), 12-zone (r=0.587, P <0.001), and 28-zone (r=0.535, P <0.001) methods. In Bland-Altman plots, each of the four LUS scoring methods had a good agreement with PASP (P <0.001). The 8-zone and 12-zone methods showed moderately accurate discriminative values in differentiating patients with an intermediate and high echocardiographic probability of PH (P <0.05). Conclusions: LUS is a readily available, inexpensive, and risk-free method that moderately correlates with PASP. LUS is a potential screening tool used for the initial investigation of PH-LHD, especially in emergencies or critical care settings.

13.
Head Face Med ; 20(1): 8, 2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38281028

RESUMO

BACKGROUND: This study aims to evaluate the difference of three-dimensional (3D) reconstructed palatal morphology between subjects with skeletal Class III and skeletal Class I in different vertical patterns using cone beam computed tomography (CBCT). METHODS: In this study, 89 subjects with skeletal Class III (49 females, 40 males; 25.45 ± 3.81 years) and 85 subjects with skeletal Class I (45 females, 40 males; 23.95 ± 4.45 years) were collected retrospectively and divided into hyperdivergent, normodivergent and hypodivergent groups. Dolphin software was used to reorient the CBCT images of these subjects. After segmenting 3D object of maxilla from the 3D skull by ProPlan software, Geomagic Studio was used to reconstruct 3D palatal morphology and establish an average 3D palatal morphology for each group. The differences of 3D palatal morphology between different groups were compared by deviation patterns on 3D colored map analysis. RESULTS: 3D colored map analysis showed the posterior part of male's palate was higher and wider than that of female's palate in skeletal Class III subjects. In skeletal Class III subjects, males with hyperdivergent pattern had a higher and narrower palate compared with hypodivergent subjects, while females with hyperdivergent had a higher but not obviously narrower palate compared with hypodivergent subjects. In the similar vertical patterns, skeletal Class III subjects had a flatter but not narrower palate compared with skeletal Class I subjects, along with a smaller palate volume. CONCLUSIONS: This method allows more intuitive between-group comparisons of the differences of 3D palatal morphology. In skeletal Class III subjects, as the vertical dimension increased, the palate tends to be higher and narrower. Therefore, the influence of vertical patterns on the palatal morphology should be fully considered in the orthodontic and orthognathic treatment of skeletal Class III subjects.


Assuntos
Mandíbula , Maxila , Humanos , Masculino , Feminino , Mandíbula/anatomia & histologia , Estudos Retrospectivos , Cefalometria/métodos , Maxila/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Palato/diagnóstico por imagem
14.
J Genet Genomics ; 51(2): 222-229, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37003352

RESUMO

Orofacial clefts (OFCs) are the most common congenital craniofacial disorders, of which the etiology is closely related to rare coding variants. Filamin B (FLNB) is an actin-binding protein implicated in bone formation. FLNB mutations have been identified in several types of syndromic OFCs and previous studies suggest a role of FLNB in the onset of non-syndromic OFCs (NSOFCs). Here, we report two rare heterozygous variants (p.P441T and p.G565R) in FLNB in two unrelated hereditary families with NSOFCs. Bioinformatics analysis suggests that both variants may disrupt the function of FLNB. In mammalian cells, p.P441T and p.G565R variants are less potent to induce cell stretches than wild type FLNB, suggesting that they are loss-of-function mutations. Immunohistochemistry analysis demonstrates that FLNB is abundantly expressed during palatal development. Importantly, Flnb-/- embryos display cleft palates and previously defined skeletal defects. Taken together, our findings reveal that FLNB is required for development of palates in mice and FLNB is a bona fide causal gene for NSOFCs in humans.


Assuntos
Encéfalo , Fenda Labial , Fissura Palatina , Animais , Humanos , Camundongos , Encéfalo/anormalidades , Fenda Labial/genética , Fissura Palatina/genética , Filaminas/genética , Mamíferos , Mutação
15.
Chemistry ; 30(14): e202303667, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38057693

RESUMO

Boosting the circularly polarized luminescence of small organic molecules has been a stubborn challenge because of weak structure rigidity and dynamic molecular motions. To investigate and eliminate these factors, here, we carried out the structure-property relationship studies on a newly-developed axial chiral scaffold of bidibenzo[b,d]furan. The molecular rigidity was finely tuned by gradually reducing the alkyl-chain length. The environmental factors were considered in solution, crystal, and polymer matrix at different temperatures. As a result, a significant amplification of the dissymmetry factor glum from 10-4 to 10-1 was achieved, corresponding to the situation from (R)-4C in solution to (R)-1C in polymer film at room temperature. A synergistic strategy of increasing the intramolecular rigidity and enhancing the intermolecular interaction to restrict the molecular motions was thus proposed to improve circularly polarized luminescence. The though-out demonstrated relationship will be of great importance for the development of high-performance small organic chiroptical systems in the future.

16.
Zool Res ; 45(1): 125-135, 2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38114438

RESUMO

Geographical background and dispersal ability may strongly influence assemblage dissimilarity; however, these aspects have generally been overlooked in previous large-scale beta diversity studies. Here, we examined whether the patterns and drivers of taxonomic beta diversity (TBD) and phylogenetic beta diversity (PBD) of breeding birds in China vary across (1) regions on both sides of the Hu Line, which demarcates China's topographical, climatic, economic, and social patterns, and (2) species with different dispersal ability. TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach. Variables representing climate, habitat heterogeneity, and habitat quality were employed to evaluate the effects of environmental filtering. Spatial distance was considered to assess the impact of dispersal limitation. Variance partitioning analysis was applied to assess the relative roles of these variables. In general, the values of TBD and PBD were high in mountainous areas and were largely determined by environmental filtering. However, different dominant environmental filters on either side of the Hu Line led to divergent beta diversity patterns. Specifically, climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions east and west of the line, respectively. Additionally, bird species with stronger dispersal ability were more susceptible to environmental filtering, resulting in more homogeneous assemblages. Our results indicated that regions with distinctive geographical backgrounds may present different ecological factors that lead to divergent assemblage dissimilarity patterns, and dispersal ability determines the response of assemblages to these ecological factors. Identifying a single universal explanation for the observed pattern without considering these aspects may lead to simplistic or incomplete conclusions. Consequently, a comprehensive understanding of large-scale beta diversity patterns and effective planning of conservation strategies necessitate the consideration of both geographical background and species dispersal ability.


Assuntos
Biodiversidade , Ecossistema , Animais , Filogenia , China , Aves/genética
17.
Nat Commun ; 14(1): 8098, 2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-38062026

RESUMO

Anti-Kasha's process in organic luminogens has attracted many attentions since its discovery. However, only limited examples of anti-Kasha's rule have been reported and anti-Kasha triplet energy transfer (ET) is even less-touched. Benefiting from anti-Kasha's rule, this work provided an efficient strategy to realize excitation wavelength dependent (Ex-De) afterglow in a host-guest system. The host has almost imperceptible RTP upon 365 nm excitation and guest is totally RTP inactive, while the doping host-guest system exhibits Ex-De afterglow with improved quantum yields. Anti-Kasha triplet ET process is realized from the higher excited triplet state T2 of host to the lowest excited singlet state S1 of the aggregated/unimolecular guest. ET efficiency in the doping system could be tuned by simply changing its processing methods to guide host and guest to adopt denser or looser intermolecular packing. The strategy of anti-Kasha triplet ET endows the host-guest doping system with multiple stimuli-responsive properties, including Ex-De afterglow, mechano-, and thermal-triggered afterglow behaviors. The corresponding applications of these properties are also realized in multiple information anti-counterfeiting and display.

18.
RSC Adv ; 13(49): 34464-34474, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38024984

RESUMO

Alloying can effectively modify electronic and optical properties of two-dimensional (2D) transition metal dichalcogenides (TMDs). However, efficient and simple methods to synthesize atomically thin TMD alloys need to be further developed. In this study, we synthesized 25 monolayer MoxW(1-x)S2ySe2(1-y) alloys by using a new liquid phase edge epitaxy (LPEE) growth method with high controllability. This straightforward approach can be used to obtain monolayer materials and operates on a self-limiting growth mechanism. The process allows the liquid solution to come into contact with the two-dimensional grains only at their edges, resulting in epitaxy confined only along the in-plane direction, which produces exclusively monolayer epitaxy. By controlling the weight ratio of MoS2/WSe2 (MoSe2/WS2), 25 monolayer MoxW(1-x)S2ySe2(1-y) alloys with different atomic ratios can be obtained on sapphire substrates, with band gap ranging from WS2 (1.55 eV) to MoSe2 (1.99 eV) and a continuously broad spectrum ranging from 623 nm to 800 nm. By adjusting the alloy composition, the carrier type and carrier mobility of alloy-based field-effect transistors can be modulated. In particular, the adjustable conductivity of MoxW(1-x)S2ySe2(1-y) alloys from n-type to bipolar type is achieved for the first time. This general synthetic strategy provides a foundation for the development of monolayer TMD alloys with multiple components and various 2D materials.

19.
Angew Chem Int Ed Engl ; 62(52): e202316647, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-37968887

RESUMO

The development of ultra-long room-temperature phosphorescence (UL-RTP) in processable amorphous organic materials is highly desirable for applications in flexible displays, anti-counterfeiting, and bio-imaging. However, achieving efficient UL-RTP from amorphous materials remains a challenging task, especially with activation by visible light and a bright afterglow. Here we report a general and rational molecular-design strategy to enable efficient visible-light-excited UL-RTP by multi-esterification of a rigid large-plane phosphorescence core. Notably, multi-esterification minimizes the aggregation-induced quenching and accomplishes a 'four birds with one stone' possibility in the generation and radiation process of UL-RTP: i) shifting the excitation from ultraviolet light to blue-light through enhancing the transition dipole moment of low-lying singlet-states, ii) facilitating the intersystem crossing process through the incorporation of lone-pair electrons, iii) boosting the decay process of long-lived triplet excitons resulting from a significantly increased transition dipole moment, and iv) reducing the intrinsic triplet nonradiative decay by substitution of high-frequency vibrating hydrogen atoms. All these factors synergistically contribute to the most efficient and stable visible-light-stimulated UL-RTP (lifetime up to 2.01 s and efficiency up to 35.4 % upon excitation at 450 nm) in flexible films using multi-esterified coronene, which allows high-tech applications in single-component time-delayed white light-emitting diodes and information technology based on flashlight-activated afterglow encryption.

20.
Org Biomol Chem ; 21(43): 8628-8641, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37860946

RESUMO

Carbon dioxide (CO2) is an available, abundant, and renewable C1 resource, which could be converted into value-added chemicals. Due to its inherent thermodynamic stability and kinetic inertness, it is difficult to realize its efficient utilization. Nevertheless, many elegant strategies for the utilization of CO2 have been developed using Lewis bases, frustrated Lewis pairs, hydroxyl-containing compounds, amino-group-containing compounds or transition metal catalysis. Among them, base-mediated carboxylation of C-nucleophiles is an environmentally friendly strategy for CO2 conversion, which is operationally simple, using low-toxicity bases and economical available promoters, without the use of complex ligands or cocatalysts. This review summarizes related work on the base-mediated carboxylation of C-nucleophiles with CO2, based on the effects of nucleophiles, promoters, additives, and solvents. The types of pronucleophile are categorized as follows: hydrocarbon with C(sp3)-H, C(sp2)-H or C(sp)-H bonds, organosilanes, organotin, organoboron, and N-tosylhydrazones. Typical mechanisms and applications of these carboxylation reactions are also depicted. Moreover, mechanistic comprehension of CO2 activation and conversion at a molecular level aims to further expand the repertoire of carboxylation transformations mediated by bases.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...