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1.
Disabil Health J ; : 101613, 2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38514295

RESUMO

BACKGROUND: Visual disabilities (VD) are expected to rise with an aging population. Persons with VD experience a higher prevalence of chronic and acute diseases. Despite the significance of influenza to this population, there is limited data comparing influenza care disparities between those with VD and those without. OBJECTIVE: The study aimed to determine the influenza burden and associated healthcare utilization in individuals with VD compared to those without disabilities. METHODS: A retrospective cohort study was conducted using the Korean National Health Information Database, encompassing three influenza seasons (2011-2012 to 2013-2014). The influenza incidence and incidence rate ratio (IRR) was calculated. Adjusted IRRs were calculated using a zero-inflated Poisson model. We assessed the risk of admissions and 30-day post-influenza mortality, employing logistic regression or survival analysis. RESULTS: A total of 504,374 patients (252,964 patients with VD and 251,410 controls) were followed for 1,471,480 person-years. The influenza incidence was higher in the VD cohort than in the control (8.8 vs. 7.8 cases per 1000 person-years). VD cohort had a higher influenza IRR (adjusted IRR 1·13, 95% confidence interval [CI] 1·02-1·25). Severe VD exhibited higher hospitalization risk (adjusted odds ratio [OR] 1·29, 95% CI 1·10-1·20) and increased medical costs. Severe VD was a significant risk factor for mortality (adjusted Hazard Ratio 1·89, 95% CI 1·04-3·45). CONCLUSIONS: People with VD have a higher influenza incidence, while their outcomes are comparable to those without. Nevertheless, severe VD significantly contributes more to hospitalization, mortality, and medical costs than controls.

2.
Chemistry ; 30(4): e202302861, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38015005

RESUMO

Organic small molecules with high photothermal conversion efficiencies that absorb near-infrared light are desirable for photothermal therapy due to their improved biocompatibility compared to inorganic materials and their ability to absorb light in the biological transparency window (650-1350 nm). Here we report three donor-acceptor organic materials DM-ANDI, O-ANDI, and S-ANDI that show high photothermal conversion efficiencies of 46-68 % with near-infrared absorption. The design of these molecules is based on the rational modification of a thermally activated delayed fluorescence material to favour a low photoluminescence quantum yield by reducing HOMO-LUMO overlap. Encapsulating these materials into either neat nanoparticles or aggregated organic dots modulates their photothermal conversion efficiencies, and also facilitates dispersion in water.

3.
J Infect Public Health ; 17(1): 76-81, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37992437

RESUMO

BACKGROUND: There is limited research into the clinical implications of the coronavirus disease 2019 (COVID-19) pandemic for non-COVID-19 pneumonia in older adults, as well as their quality of care or outcomes. This study aims to assess the process and outcome quality of care for hospitalized older adult patients with pneumonia before and after the pandemic. METHODS: A retrospective cohort of older adult patients (age ≥ 65) hospitalized for non-COVID pneumonia were recruited from five Korean hospitals (January 20, 2019, to January 19, 2021). The quality of care before and after the COVID-19 pandemic was evaluated. RESULTS: A total of 7356 hospitalization episodes of older adult pneumonia were identified, and 978 cases (552 pre-pandemic and 426 during the pandemic) were analyzed. The pneumonia severity score was higher during the pandemic, and the waiting time from the emergency room to admission was also longer. Furthermore, the pneumonia mortality rate during the pandemic was higher than that in the pre-pandemic period (in-hospital mortality: 10.1% vs. 18.1%; 90-day mortality: 11.6% vs. 22.3%). A significantly higher mortality risk was observed during the pandemic than in the period prior (adjusted odds ratio: 1.74, 95% confidence interval: 1.14-2.63). CONCLUSIONS: While the quality of care for hospitalized pneumonia has been maintained during the pandemic, there has been an increase in mortality rates. Further investigations are needed to understand the underlying causes of this increase.


Assuntos
COVID-19 , Pneumonia , Humanos , Idoso , COVID-19/terapia , Pandemias , SARS-CoV-2 , Estudos Retrospectivos , Pneumonia/epidemiologia , Pneumonia/terapia , Hospitalização
4.
Inorg Chem ; 62(33): 13173-13178, 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37552800

RESUMO

Chiral metal-organic frameworks (CMOFs) and solid-state [2 + 2] photocyclization have been explored as independent areas in crystal engineering. We herein report the photoreactive CMOFs that undergo a [2 + 2] photocycloaddition reaction for the first time. Through the incorporation of a dipyridyl olefin ligand, 1,4-bis[2-(4-pyridyl)ethenyl]benzene, and d-camphoric acid or l-camphoric acid, we constructed a pair of homochiral Zn(II) CMOFs (d-1 or l-1) with a two-dimensional sql topology via a two-step procedure to avoid racemization. Both d-1 and l-1 were photoinert due to the large olefin bond separation. The removal of the solvent molecules between layers enabled them (d-1a and l-1a) to undergo [2 + 2] cycloaddition reactions; d-1a is more reactive (70%) than l-1a (20%) probably due to proper desolvation-induced rearrangement. The photoluminescence properties are also discussed. This work presents a new perspective on photoreactive homochiral network materials with diverse topologies and applications.

5.
Angew Chem Int Ed Engl ; 62(32): e202301186, 2023 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-37189285

RESUMO

Artificial lighting currently consumes approximately one-fifth of global electricity production. Organic emitters with white persistent RTP have potential for applications in energy-efficient lighting technologies, due to their ability to harvest both singlet and triplet excitons. Compared to heavy metal phosphorescent materials, they have significant advantages in cost, processability, and reduced toxicity. Phosphorescence efficiency can be improved by introducing heteroatoms, heavy atoms, or by incorporating luminophores within a rigid matrix. White-light emission can be achieved by tuning the ratio of fluorescence to phosphorescence intensity or by pure phosphorescence with a broad emission spectrum. This review summarizes recent advances in the design of purely organic RTP materials with white-light emission, describing single-component and host-guest systems. White phosphorescent carbon dots and representative applications of white-light RTP materials are also introduced.

6.
Disabil Health J ; 16(1): 101372, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36156272

RESUMO

BACKGROUND: Previous research on vaccination among people with disabilities has focused on children or adolescents. OBJECTIVE: To examine variations in seasonal influenza vaccination (SIV) uptake according to disability type and age group and explore the vulnerable groups and risk factors of non-vaccination to identify areas of policy support in Korea. METHODS: This pooled cross-sectional study included adults who participated in the 2011, 2014, and 2017 National Survey of Persons with Disabilities. The dependent variable was SIV uptake. Age-stratified multivariate logistic regression was conducted to assess its relationship with disability characteristics. RESULTS: Among 18,069 adults with disabilities, the overall SIV uptake rate increased with age (33.8%, 50.1%, and 85.3% in 20-49, 50-65, and ≥65 years, respectively). In the multivariate analyses (reporting the adjusted odds ratio and 95% confidence interval), severe disability was associated with lower and higher SIV uptake rates in older adults and younger age-groups (0.88, 0.76-1.01; 1.62, 1.42-1.86; and 1.54, 1.24-1.92 in those aged ≥65; 50-64; and 20-49 years), respectively. Health behaviors (regular doctor visits, general health examinations, and non-smoking) were significantly associated with higher odds of SIV uptake. After adjusting for covariates (age, medical conditions, functional ability, and behavioral factors), individuals with brain, epileptic, and psychiatric disabilities showed lower odds of SIV uptake compared to those with internal organ disabilities across all age groups. CONCLUSIONS: Policy initiatives that can improve the health behaviors of people with disabilities (especially the elderly and people with intellectual, brain, epilepsy, and psychiatric disabilities) to promote SIV uptake are needed.


Assuntos
Pessoas com Deficiência , Vacinas contra Influenza , Influenza Humana , Idoso , Adolescente , Criança , Humanos , Influenza Humana/prevenção & controle , Estações do Ano , Estudos Transversais , República da Coreia
7.
Front Public Health ; 10: 922043, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35991017

RESUMO

Objective: We assessed the collateral impact of the COVID-19 pandemic on healthcare service use among people with disabilities. Methods: We utilized the COVID-19 database from the Korean National Health Insurance Service claims from 2015 until June 2020. We included 5,850 people with disabilities and matched 5,850 without disabilities among those who were neither tested nor diagnosed with COVID-19. We used a quasi-experimental setting with a COVID-19 outbreak as an external event in a difference-difference estimation with matching controls. Results: Participants with disabilities recorded a larger decrease in the number of claims for total services (2.1 claims per 5 months) upon the COVID-19 pandemic's onset compared to those without disabilities (1.6 claims), and the difference-in-difference estimates were statistically significant (0.46 claims). The decline was driven by outpatient and emergency visits. The extent of the decline was large for the severe disability group overall. By disability type, those with a physical disability showed a statistically significant decline in the number of claims. Conclusion: The COVID-19 pandemic has had a collateral impact on people with disabilities' use of healthcare services. Continued assessment is needed regarding whether the collateral impact has been sustained or is following a different path.


Assuntos
COVID-19 , Pessoas com Deficiência , COVID-19/epidemiologia , Serviços de Saúde , Acessibilidade aos Serviços de Saúde , Humanos , Pandemias
8.
Chem Sci ; 13(11): 3109-3117, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35414882

RESUMO

The study of chiral self-sorting is extremely important for understanding biological systems and for developing applications for the biomedical field. In this study, we attempted unprecedented chiral self-sorting supramolecular polymerization accompanying helical inversion with Ag+ in one enantiomeric component. Bola-type terpyridine-based ligands (R-L1 and S-L1) comprising R- or S-alanine analogs were synthesized. First, R-L1 dissolved in DMSO/H2O (1 : 1, v/v) forms right-handed helical fibers (aggregate I) via supramolecular polymerization. However, after the addition of AgNO3 (0.2-1.1 equiv.) to the R-L1 ligand, in particular, it was found that aggregate II with left-handed helicity is generated from the [R-L1(AgNO3)2] complex through the [R-L1Ag]+ complex via the dissociation of aggregate I by a multistep with an off pathway, thus demonstrating interesting self-sorting properties driven by helicity and shape discrimination. In addition, the [R-L1(AgNO3)2] complex, which acted as a building block to generate aggregate III with a spherical structure, existed as a metastable product during the formation of aggregate II in the presence of 1.2-1.5 equiv. of AgNO3. Furthermore, the AFM and CD results of two samples prepared using aggregates I and III with different volume ratios were similar to those obtained upon the addition of AgNO3 to free R-L1. These findings suggest that homochiral self-sorting in a mixture system occurred by the generation of aggregate II composed of the [R-L1Ag]+ complex via the rearrangement of both, aggregates I and III. This is a unique example of helicity- and shape-driven chiral self-sorting supramolecular polymerization induced by Ag+ starting from one enantiomeric component. This research will improve understanding of homochirality in complex biological models and contribute to the development of new chiral materials and catalysts for asymmetric synthesis.

9.
Chem Sci ; 13(5): 1484-1491, 2022 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-35222933

RESUMO

Planarized triarylboranes are attracting increasing attention not only as models of boron-doped graphenes, but also as promising materials for organic optoelectronics. In particular, polycyclic aromatic hydrocarbon (PAH) skeletons with embedded boron atom(s) in the inner positions are of importance in light of their high chemical stability and π-stacking ability derived from their planar geometries. Herein, we disclose a robust synthesis of such fully fused boron-doped PAHs and their self-assembly behavior in aqueous media to explore their potential utility in biological applications. The synthesis using in situ-generated planar diarylboranes as a key precursor afforded a series of fully fused boron-doped PAHs, even including an amphiphilic derivative with hydrophilic side chains. These compounds exhibited red emission in solution, and slight structural modification resulted in increased fluorescence brightness. While these compounds showed relatively low Lewis acidity compared to their partially ring-fused counterparts, their Lewis acidities were slightly increased in polar solvents compared to those in nonpolar solvents. In addition, their B-N Lewis acid-base adducts, even those with a strong, charge-neutral Lewis base such as N,N-dimethylaminopyridine (DMAP), exhibited photo-dissociation behavior in the excited state. The amphiphilic derivative showed significant spectral changes with increased water content in DMSO/H2O mixed media and formed sheet-like aggregates. The disassembly and assembly processes of the aggregates were externally controlled by the addition of DMAP and an acid, accompanied by a change in the fluorescence intensity.

10.
Sci Rep ; 11(1): 11243, 2021 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-34045533

RESUMO

Influenza is an important public health concern. We propose a new real-time influenza-like illness (ILI) surveillance system that utilizes a nationwide prospective drug utilization monitoring in Korea. We defined ILI-related claims as outpatient claims that contain both antipyretic and antitussive agents and calculated the weekly rate of ILI-related claims, which was compared to weekly ILI rates from clinical sentinel surveillance data during 2014-2018. We performed a cross-correlation analysis using Pearson's correlation, time-series analysis to explore actual correlations after removing any dubious correlations due to underlying non-stationarity in both data sets. We used the moving epidemic method (MEM) to estimate an absolute threshold to designate potential influenza epidemics for the weeks with incidence rates above the threshold. We observed a strong correlation between the two surveillance systems each season. The absolute thresholds for the 4-years were 84.64 and 86.19 cases per 1000claims for claims data and 12.27 and 16.82 per 1000 patients for sentinel data. The epidemic patterns were more similar in the 2016-2017 and 2017-2018 seasons than the 2014-2015 and 2015-2016 seasons. ILI claims data can be loaded to a drug utilization review system in Korea to make an influenza surveillance system.


Assuntos
Influenza Humana/epidemiologia , Adulto , Epidemias , Humanos , Saúde Pública , República da Coreia , Vigilância de Evento Sentinela
11.
J Korean Med Sci ; 36(14): e89, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33847080

RESUMO

BACKGROUND: The occurrence of hepatocellular carcinoma (HCC) is a major concern during antiviral therapy for chronic hepatitis B. There are conflicting opinions regarding the effects of entecavir (ETV) and tenofovir disoproxil fumarate (TDF) on HCC prevention. We assessed these two antiviral medications for preventing HCC in treatment-naïve patients with chronic hepatitis B. METHODS: We conducted a retrospective cohort study using nationwide claims data from the Korea Health Insurance Review and Assessment Service. We included 55,473 treatment-naïve adult cases where ETV or TDF treatment was started between 2013 and 2017 (cohort 1). The ETV and TDF groups were matched 1:2 based on age, sex, comorbidities, hospital type, and index date year. Patients were followed up until December 2018. The outcome was the development of HCC. Subgroup analyses were conducted according to sex, age, hospital type and the presence of cirrhosis. We also compared the outcomes of patients who had started antiviral therapy during the 2012-2014 period (cohort 2). RESULTS: The matched participants (18,491 in the ETV and 36,982 in the TDF groups) were a part of the study for, on average, 41.2 months. The incidence of HCC did not differ significantly between the ETV (1.46 per 100 patient-years) and the TDF (1.36 per 100 patient-years) treatments (hazard ratio, 0.93; 95% confidence interval, 0.86-1.01; P = 0.081). By contrast, HCC incidence was significantly higher in the ETV group than tenofovir group of cohort 2. CONCLUSION: In patients with chronic hepatitis B, the ETV treatment did not result in a higher rate of HCC than the TDF treatment.


Assuntos
Antivirais/uso terapêutico , Carcinoma Hepatocelular/diagnóstico , Guanina/análogos & derivados , Hepatite B Crônica/tratamento farmacológico , Neoplasias Hepáticas/diagnóstico , Tenofovir/uso terapêutico , Adulto , Idoso , Carcinoma Hepatocelular/epidemiologia , Carcinoma Hepatocelular/etiologia , Bases de Dados Factuais , Feminino , Guanina/uso terapêutico , Hepatite B Crônica/complicações , Humanos , Incidência , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/etiologia , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , República da Coreia/epidemiologia , Estudos Retrospectivos , Adulto Jovem
12.
J Am Chem Soc ; 143(7): 2953-2961, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33565863

RESUMO

We report the kinetically controlled supramolecular polymerization of boron-containing π-conjugated molecules, which was enabled by a seeding method based on dual trapping of a metastable state by synergistic intramolecular hydrogen bonding and Lewis acid-based complexation. Planarized triarylborane-based 1, which bears a diamide chain with chiral alkyl groups, was synthesized. Upon cooling, the solution of monomer 1 afforded a supramolecular polymerization in a cooperative manner to form helical supramolecular nanostructures with intense J-type aggregate emission. In the presence of pyridine, the triarylborane moiety formed a Lewis acid-base complex, which enhances the stabilization of the metastable monomeric state. An assembly incompetent structure with a folded diamide chain conformation and a pyridine moiety axially coordinated to the boron atom is responsible for slowing the spontaneous aggregation. The seeding method was successfully applied to the solution to produce homogeneous nanofibers even at a high (millimolar-level) concentration. This unprecedented kinetic control via dual trapping provides an effective method to achieve seed-initiated polymerization under concentrated conditions.

13.
Nanoscale ; 12(32): 16685-16689, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32785324

RESUMO

We demonstrated the exciplex emission of supramolecular polymers (Bipy-1) possessing bipyridine and pyrene moieties. The distinctive exciplex emission of the supramolecular polymers was controlled by tuning the molecular conformation in different composition ratios of a mixed DMSO/H2O solution. The strong exciplex emission of the supramolecular polymer I with yellow emission was a consequence of the intramolecular charge-transfer interactions in a mixed DMSO/H2O (60 : 40-1 : 99 v/v) solution.

14.
BMJ Open ; 9(8): e028880, 2019 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-31446408

RESUMO

OBJECTIVES: Although obesity is a risk factor for stroke, its impact on mortality in patients with stroke remains unclear. In this study, we aimed to evaluate the relationship between body mass index (BMI) and mortality due to ischaemic stroke among adults aged 20 years and above in Korea. DESIGN: Retrospective cohort study. SETTING: A tertiary-hospital-based stroke registry linked to the death records. PARTICIPANTS: 3599 patients admitted for ischaemic stroke from January 2007 to June 2013. OUTCOME MEASURES: The HRs for all-cause and stroke-related mortality were calculated using Cox proportional hazards models. Progression from stroke-related mortality was assessed using the Fine-Grey competing risk model, treating other-cause mortality as a competing risk. Adjustments were made for age, gender, smoking status, Charlson comorbidity index, cardiovascular or non-cardiovascular comorbidities, stroke severity, severity related to other medical conditions, complications and enrolment year. We repeated the analysis with stratification based on age groups (less than 65 vs 65 years and above). RESULTS: For stroke-related mortality, there was no significant difference among the four BMI groups. The risk of all-cause mortality was 36% higher in the underweight group than in the normal weight group (long-term HR=1.36, 95% CI: 1.04 to 1.79), whereas the mortality risk of the obese group was significantly lower (HR=0.66, 95% CI: 0.54 to 0.81). Although this relationship was not estimated in the younger group, it was found that obesity had a protective effect on the all-cause mortality in the elderly (long-term HR=0.66, 95% CI: 0.52 to 0.83). CONCLUSIONS: Obesity is more likely to reduce mortality risk than normal weight, especially in elderly patients.


Assuntos
Índice de Massa Corporal , Obesidade/epidemiologia , Acidente Vascular Cerebral/mortalidade , Magreza/epidemiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/complicações , Feminino , Humanos , Peso Corporal Ideal , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Fatores de Proteção , República da Coreia/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Acidente Vascular Cerebral/etiologia , Adulto Jovem
15.
J Nanosci Nanotechnol ; 19(5): 2903-2908, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30501798

RESUMO

Uranium is a crucial raw material in the nuclear energy industry; however, its radioactive nature makes it a critically damaging component to both the atmosphere and human health. In this study, we report a simple and cost-effective selective colorimetric detection technique for UO2+2 using nitrophenyldiacetic acids (NPD)-functionalized gold nanoparticles (Au NPs 1). The hybrid Au NPs 1 can be induced to aggregate in the presence of UO2+2 ions. UO2+2 can be recognized by the colorimetric response of hybrid Au NPs 1, which can be observed by a UV-Vis spectrophotometer and it is easily detectable by the naked eye. The hybrid Au NPs 1 bound by UO2+2 possess a good selective response compared to other metal ions (Li+, Na+, K+, Rb+, Cs+, Ca2+, Mg2+, Ba2+, Ni2+, Zn2+, and Co2+), which can be observed by a prominent color change. The color of the hybrid Au NPs 1 changed from red to dark red upon addition of UO2+2 in the presence of other metal ions. Job's plot demonstrates that one NPD moiety attached onto the surface of Au NPs 1 forms 1:1 stoichiometry with UO2+2, hence providing a simple and effective colorimetric sensor for the real-time detection of UO2+2.

16.
Chem Sci ; 11(3): 721-730, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-34123045

RESUMO

We report kinetically controlled chiral supramolecular polymerization based on ligand-metal complex with a 3 : 2 (L : Ag+) stoichiometry accompanying a helical inversion in water. A new family of bipyridine-based ligands (d-L1, l-L1, d-L2, and d-L3) possessing hydrazine and d- or l-alanine moieties at the alkyl chain groups has been designed and synthesized. Interestingly, upon addition of AgNO3 (0.5-1.3 equiv.) to the d-L1 solution, it generated the aggregate I composed of the d-L1AgNO3 complex (d-L1 : Ag+ = 1 : 1) as the kinetic product with a spherical structure. Then, aggregate I (nanoparticle) was transformed into the aggregate II (supramolecular polymer) based on the (d-L1)3Ag2(NO3)2 complex as the thermodynamic product with a fiber structure, which led to the helical inversion from the left-handed (M-type) to the right-handed (P-type) helicity accompanying CD amplification. In contrast, the spherical aggregate I (nanoparticle) composed of the d-L1AgNO3 complex with the left-handed (M-type) helicity formed in the presence of 2.0 equiv. of AgNO3 and was not additionally changed, which indicated that it was the thermodynamic product. The chiral supramolecular polymer based on (d-L1)3Ag2(NO3)2 was produced via a nucleation-elongation mechanism with a cooperative pathway. In thermodynamic study, the standard ΔG° and ΔH e values for the aggregates I and II were calculated using the van't Hoff plot. The enhanced ΔG° value of the aggregate II compared to that of the formation of aggregate I confirms that aggregate II was thermodynamically more stable. In the kinetic study, the influence of concentration of AgNO3 confirmed the initial formation of the aggregate I (nanoparticle), which then evolved to the aggregate II (supramolecular polymer). Thus, the concentration of the (d-L1)3Ag2(NO3)2 complex in the initial state plays a critical role in generating aggregate II (supramolecular polymer). In particular, NO3 - acts as a critical linker and accelerator in the transformation from the aggregate I to the aggregate II. This is the first example of a system for a kinetically controlled chiral supramolecular polymer that is formed via multiple steps with coordination structural change.

17.
Nanomaterials (Basel) ; 8(12)2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30545092

RESUMO

We report self-assembled novel triphenylphosphonium-conjugated dicyanostilbene-based as selective fluorescence turn-on probes for ¹O2 and ClO-. Mono- or di-triphenylphosphonium-conjugated dicyanostilbene derivatives 1 and 2 formed spherical structures with diameters of ca. 27 and 56.5 nm, respectively, through π-π interaction between dicyanostilbene groups. Self-assembled 1 showed strong fluorescent emission upon the addition of ¹O2 and ClO- compared to other ROS (O2-, •OH, NO, TBHP, H2O2, GSH), metal ions (K⁺, Na⁺), and amino acids (cysteine and histidine). Upon addition of ¹O2 and ClO-, the spherical structure of 1 changed to a fiber structure (8-nm wide; 300-nm long). Upon addition of ¹O2 and ClO-, the chemical structural conversion of 1 was determined by FAB-Mass, NMR, IR and Zeta potential analysis, and the strong emission of the self-assembled 1 was due to an aggregation-induced emission enhancement. This self-assembled material was the first for selective ROS as a fluorescence turn-on probe. Thus, a nanostructure change-derived turn-on sensing strategy for ¹O2 or ClO- may offer a new approach to developing methods for specific guest molecules in biological and environmental subjects.

18.
Chem Asian J ; 13(19): 2847-2853, 2018 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-29987887

RESUMO

This paper describes the peculiar co-assembly supramolecular polymerization behavior of triphenylamine trisamide derivatives with d-alanine (T-ala) or glycine (T-gly) moieties. Concentration and temperature-dependent circular dichroism (CD) spectroscopy revealed that the heating curves of co-assemblies obtained at various molar ratios of T-ala to T-gly exhibited two distinct transition temperatures. The first transition was due to the transformation from coiled helical bundles to single helical fibers without handedness. The second was due to a change from typical elongation to nucleation. These phenomena were confirmed by solvent-dependent decoiling of coiled helical structures and concentration-dependent morphological analysis. The two transitioning temperatures were dependent on the concentration of T-ala in the co-assemblies, suggesting that T-ala concentration plays an important role in the formation of coiled helical bundles. Our study demonstrated the first observation of two distinct transition temperatures in supramolecular polymers.

19.
Inorg Chem ; 57(1): 16-19, 2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-29235860

RESUMO

We demonstrate the different origins of helical directions in polymeric gels derived from a hydrazone reaction in the absence and presence of Ni2+. The right-handed helicity of polymeric gels without Ni2+ originates from the enantiomeric d-form alanine moiety embedded in the building block. However, the right-handed helicity is inverted to a left-handed helicity upon the addition of Ni2+, indicating that added Ni2+ greatly affects the conformation of the polymeric gel by overcoming the influence of the enantiomer embedded in the building block on the helicity at the supramolecular level. More interestingly, the ratio of the right-toleft-handed helical fibers varies with the concentration of Ni2+, which converts from 100% right-handed helical fiber to 90% left-handed helical fiber. In the presence of Ni2+, both right- and left-handed helical fibers coexist at the supramolecular level. Some fibers also exhibit both right- and left-handed helicities in a single fiber.

20.
J Am Chem Soc ; 139(49): 17711-17714, 2017 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-29161032

RESUMO

Transfer and inversion of supramolecular chirality from chiral calix[4]arene analogs (3D and 3L) with an alanine moiety to an achiral bipyridine derivative (1) with glycine moieties in a coassembled hydrogel are demonstrated. Molecular chirality of 3D and 3L could transfer supramolecular chirality to an achiral bipyridine derivative 1. Moreover, addition of 0.6 equiv of 3D or 3L to 1 induced supramolecular chirality inversion of 1. More interestingly, the 2D-sheet structure of the coassembled hydrogels formed with 0.2 equiv of 3D or 3L changed to a rolled-up tubular structure in the presence of 0.6 equiv of 3D or 3L. The chirality inversion and morphology change are mainly mediated by intermolecular hydrogen-bonding interactions between the achiral and chiral molecules, which might be induced by reorientations of the assembled molecules, confirmed by density functional theory calculations.

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