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1.
PLOS Glob Public Health ; 4(5): e0003000, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38722816

RESUMO

Applying a positive outlier lens is one effective approach for generating evidence to inform global health policy, program, and funding decisions. Exemplars in Global Health (EGH) is a program that studies positive outlier countries that have made extraordinary progress in health outcomes (despite limited resources) and disseminates their successes through multiple types of outputs. To date, EGH has studied, or is studying, 14 global health topics in 28 countries. This paper aims to identify findings, summarized as themes and sub-themes, that appear among all completed EGH studies. We developed a conceptual framework and used a content analysis approach to identify the top thematic areas that appear as drivers for programmatic success across EGH studies that were completed between June 2020-May 2023. The EGH studies (N = 31) spanned six topics including under-five child mortality (n = 6), childhood stunting (n = 5), community health workers (CHW) (n = 4), vaccine delivery (n = 3), COVID-19 response (n = 6), and newborn and maternal mortality reduction (n = 7) across 19 countries in sub-Saharan Africa, Latin America, South and Central Asia, and the Caribbean regions. Top drivers of success were defined as those critical or catalytic in achieving the intended outcome. Eight key drivers were identified: (1) efficient data collection and use for decision-making, (2) strong political commitment and health leadership, (3) effective stakeholder coordination, (4) a local, connected, and capacitated workforce, (5) intentional women's empowerment and engagement, (6) effective adoption and implementation of national policies, (7) effective and sustainable financing, and (8) equitable, efficient outreach and targeting. These cross-cutting drivers span a broad range of development outcomes, sectors, and populations, and indicate a need to effectively integrate people, systems, and sectors to improve global health outcomes. Findings from this study aim to support peer learning among countries and support evidence-based decision-making for funders, policymakers, and other key stakeholders.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38702252

RESUMO

OBJECTIVES: Pain is increasingly becoming common among middle-aged and older adults. While research on the association between pain characteristics and sleep problems (SP) is limited in low- and middle-income countries, the underlying mechanisms of the association are poorly understood. This study examines the association of bodily pain intensity and pain interference with SP and investigates the mediating role of activity limitation and emotional distress in this association. METHODS: We analyzed population-based data, including 1,201 individuals aged ≥50 (mean [SD] age 66.14 [11.85] years) from the 2016-2018 AgeHeaPsyWel-HeaSeeB study in Ghana. Multiple OLS regressions and serial multiple mediation modeling using bootstrapping analyses examined direct and indirect effects from pain to SP through activity limitation and emotional distress. RESULTS: Regressions demonstrated that pain intensity and interference were significantly associated with higher levels of activity limitation, emotional distress, and SP (range: ß = 0.049-0.658). Bootstrapping analysis showed that activity limitation and emotional distress serially mediated the relationship between pain intensity and SP (total effect: ß = 0.264, Bootstrap 95% confidence interval [CI] = 0.165-0.362; direct effect: (ß = 0.107, Bootstrap 95% CI = 0.005-0.210; total indirect effect: ß = 0.156, Bootstrap 95% CI = 0.005-0.210) accounting for ∼59%. Activity limitation and emotional distress mediated pain interference and SP association (total effect: ß = 0.404, Bootstrap 95% CI = 0.318-0.490; direct effect: ß = 0.292, Bootstrap 95% CI = 0.201-0.384; and total indirect effect: ß = 0.112, Bootstrap 95% CI = 0.069-0.156) yielding ∼28%. CONCLUSION: Our data suggest that activity limitation and emotional distress may convey stress-related risks of pain on SP. Future research should evaluate if activity limitation and emotional distress could be effective targets to reduce the effect of pain on sleep in later-life.

3.
Small ; : e2312022, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38698610

RESUMO

Photosynthesis of H2O2 from earth-abundant O2 and H2O molecules offers an eco-friendly route for solar-to-chemical conversion. The persistent challenge is to tune the photo-/thermo- dynamics of a photocatalyst toward efficient electron-hole separation while maintaining an effective driving force for charge transfer. Such a case is achieved here by way of a synergetic strategy of sub-band-assisted Z-Scheme for effective H2O2 photosynthesis via direct O2 reduction and H2O oxidation without a sacrificial agent. The optimized SnS2/g-C3N4 heterojunction shows a high reactivity of 623.0 µmol g-1 h-1 for H2O2 production under visible-light irradiation (λ > 400 nm) in pure water, ≈6 times higher than pristine g-C3N4 (100.5 µmol g-1 h-1). Photodynamic characterizations and theoretical calculations reveal that the enhanced photoactivity is due to a markedly promoted lifetime of trapped active electrons (204.9 ps in the sub-band and >2.0 ns in a shallow band) and highly improved O2 activation, as a result of the formation of a suitable sub-band and catalytic sites along with a low Gibbs-free energy for charge transfer. Moreover, the Z-Scheme heterojunction creates and sustains a large driving force for O2 and H2O conversion to high value-added H2O2.

4.
Artigo em Inglês | MEDLINE | ID: mdl-38641509

RESUMO

OBJECTIVES: Limited data exist on the association between physical activity (PA) and depression in older adults from low- and middle-income countries (LMICs). In this study, we examine the association between meeting the World Health Organization (WHO) PA guidelines and depression in adults aged ≥50 years in Ghana and investigate the psychosomatic factors explaining this association. METHODS: Cross-sectional data from the Aging, Health, Psychological Well-being, and Health-seeking Behavior Study in Ghana (2016-18) were analyzed. Depression was assessed with the Center for Epidemiological Studies Depression Scale (CES-D-10). PA was assessed using the International Physical Activity Questionnaire Short Form (IPAQ-SF). Multivariable logistic regression and Hayes PROCESS macro with bootstrapping mediation analyses were performed to evaluate the hypothesized associations. RESULTS: The study included 1201 individuals (mean [SD] age 66.1 [11.9] years; 63.3% women). The prevalence of meeting PA guidelines and depression was 36.7% and 29.5%, respectively. Meeting the WHO-recommended PA guidelines was associated with a 16% lower rate of developing depression even after adjusting for potential confounders (OR = 0.84, p <0.001). This association was much stronger among men and those aged 50-64 years. Loneliness, social isolation, sleep problems, functional limitations, and pain characteristics largely mediated the association of PA with depression. CONCLUSIONS: PA was negatively associated with depression among older adults in Ghana, and psychosocial and physical factors partially explained the association. The promotion of PA in old age may aid in the prevention of depression, especially in men and those aged 50-64 years. Longitudinal data may confirm our findings.

5.
J Am Chem Soc ; 146(15): 10679-10686, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38579336

RESUMO

Nitrenium ions are important reactive intermediates participating in the synthetic chemistry and biological processes. Little is known about triplet phenyl nitrenium ions regarding their reactivity, lifetimes, spectroscopic features, and electronic configurations, and no ground state triplet nitrenium ion has been directly detected. In this work, m-pyrrolidinyl-phenyl hydrazine hydrochloride (1) is synthesized as the photoprecursor to photochemically generate the corresponding m-pyrrolidinyl-phenyl nitrenium ion (2), which is computed to adopt a π, π* triplet ground state. A combination of femtosecond (fs) and nanosecond (ns) transient absorption (TA) spectroscopy, cryogenic continuous-wave electronic paramagnetic resonance (CW-EPR) spectroscopy, computational analysis, and photoproduct studies was performed to elucidate the photolysis pathway of 1 and offers the first direct experimental detection of a ground state triplet phenyl nitrenium ion. Upon photoexcitation, 1 forms S1, where bond heterolysis occurs and the NH3 leaving group is extruded in 1.8 ps, generating a vibrationally hot, spin-conserving closed-shell singlet phenyl nitrenium ion (12) that undergoes vibrational cooling in 19 ps. Subsequent intersystem crossing takes place in 0.5 ns, yielding the ground state triplet phenyl nitrenium ion (32), with a lifetime of 0.8 µs. Unlike electrophilic singlet phenyl nitrenium ions, which react rapidly with nucleophiles, this triplet phenyl nitrenium reacts through sequential H atom abstractions, resulting in the eventual formation of the reduced m-pyrrolidinyl-aniline as the predominant stable photoproduct. Supporting the triplet ground state, continuous irradiation of 1 in a glassy matrix at 80 K in an EPR spectrometer forms a paramagnetic triplet species, consistent with a triplet nitrenium ion.

6.
Nat Commun ; 15(1): 2561, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519517

RESUMO

Cocrystal engineering is an efficient and simple strategy to construct functional materials, especially for the exploitation of novel and multifunctional materials. Herein, we report two kinds of nucleic-acid-base cocrystal systems that imitate the strong hydrogen bond interactions constructed in the form of complementary base pairing. The two cocrystals studied exhibit different colors of phosphorescence from their monomeric counterparts and show the feature of rare high-temperature phosphorescence. Mechanistic studies reveal that the strong hydrogen bond network stabilizes the triplet state and suppresses non-radiative transitions, resulting in phosphorescence even at 425 K. Moreover, the isolation effects of the hydrogen bond network regulate the interactions between the phosphor groups, realizing the manipulation from aggregation to single-molecule phosphorescence. Benefiting from the long-lived triplet state with a high quantum yield, the generation of reactive oxygen species by energy transfer is also available to utilize for some applications such as in photodynamic therapy and broad-spectrum microbicidal effects. In vitro experiments show that the cocrystals efficiently kill bacteria on a tooth surface and significantly help prevent dental caries. This work not only provides deep insight into the relationship of the structure-properties of cocrystal systems, but also facilitates the design of multifunctional cocrystal materials and enriches their potential applications.


Assuntos
Anti-Infecciosos , Cárie Dentária , Ácidos Nucleicos , Humanos , Cristalização , Anti-Infecciosos/farmacologia
7.
Opt Express ; 32(4): 5783-5792, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38439296

RESUMO

Millimeter and terahertz wave imaging has emerged as a powerful tool for applications such as security screening, biomedical imaging, and material analysis. However, intensity images alone are often insufficient for detecting variations in the dielectric constant of a sample, and extraction of material properties without additional phase information requires extensive prior knowledge of the sample. Digital holography provides a means for intensity-only detectors to reconstruct both amplitude and phase images. Here we utilize a commercially available source and detector array, both operating at room temperature, to perform digital holography in real-time for the first time in the mm-wave band (at 290 GHz). We compare the off-axis and phase-shifting approaches to digital holography and discuss their trade-offs and practical challenges in this regime. Owing to the low pixel count, we find phase-shifting holography to be the most practical and high fidelity approach for such commercial mm-wave cameras even under real-time operational requirements.

8.
ChemistryOpen ; : e202300285, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38456364

RESUMO

This research article uses density functional theory (DFT) to study photoinduced borylation. This work examined the electron donor-acceptor complex (EDA) of bis(catecholato)diboron with different redox-active leaving groups and bis(pinacol)diboron with aryl N-hydroxyphthalimide. The results of these DFT studies show the complex ratio of B2 cat2 and N, N-dimethylacetamide (DMA) should be 1 : 2 which is consistent with the experimental results in the literature. We further proposed a reaction mechanism and calculated the energies associated with each step.

9.
Maturitas ; 183: 107963, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38471332

RESUMO

OBJECTIVES: This study investigates whether differences in individual-level and provincial-level health funding could explain or mitigate health inequalities among older people in terms of non-communicable diseases within a population served by fragmented health insurance schemes. STUDY DESIGN: A national repeated cross-sectional analysis was done of the 2008, 2011, 2014, and 2018 Chinese Longitudinal Healthy Longevity Surveys. These provided a total of 44,623 persons aged 60 and over. MAIN OUTCOME MEASURES: Respondents were asked whether they had been diagnosed with any types of non-communicable diseases by doctors. A dichotomous outcome variable was constructed to indicate whether older people had any diagnosed non-communicable diseases. RESULTS: Compared with uninsured older persons, those who were enrolled in social health insurance schemes designed for civil servants as cadres, urban employees and urban residents were more likely to report a higher incidence of non-communicable diseases. There were no significant differences in the prevalence of non-communicable diseases between uninsured older people and those in the New Rural Cooperative Medical Scheme. Although the incidence of non-communicable diseases among older persons increased over the study period, greater health expenditure was significantly associated with a lower risk of non-communicable diseases. The interaction results between individual social health insurance schemes and public health expenditure indicate that disparities in the incidence of non-communicable diseases among different health insurance schemes diminish as public health expenditure increases. Older individuals with Public Free Medical Services benefited the most in provinces with higher public health expenditure compared with other health insurance schemes. CONCLUSIONS: Given the evidence of the beneficial effects of universal health coverage on non-communicable diseases among older persons, these results should encourage policy makers to increase public health funding and to raise the overall benefit packages for social health insurance schemes.


Assuntos
Gastos em Saúde , Doenças não Transmissíveis , Humanos , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Doenças não Transmissíveis/epidemiologia , Incidência , Estudos Transversais , Despesas Públicas , Seguro Saúde , China/epidemiologia
10.
Molecules ; 29(4)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38398594

RESUMO

The 3',5'-dimethoxybenzoin (DMB) system has been widely investigated as a photoremovable protecting group (PRPG) for the elimination of various functional groups and has been applied in many fields. The photolysis of DMB fluoride leads to a highly efficient photocyclization-deprotection reaction, resulting in a high yield of 3',5'-dimethoxybenzofuran (DMBF) in a MeCN solution, while there is a competitive reaction that produces DMB in an aqueous solution. The yield of DMB increased as the volume ratio of water increased. To understand the solvent effect of the photolysis of selected DMB-based compounds, a combination of femtosecond to nanosecond transient absorption spectroscopies (fs-TA and ns-TA), nanosecond time-resolved resonance Raman spectroscopy (ns-TR3) and quantum chemical calculation was employed to study the photophysical and photochemical reaction mechanisms of DMB fluoride in different solutions. Facilitated by the bichromophoric nature of DMB fluoride with electron-donating and -withdrawing chromophores, the cyclized intermediates could be found in a pure MeCN solution. The deprotection of a cyclic biradical intermediate results in the simultaneous formation of DMBF and a cyclic cation species. On the other hand, in aqueous solution, fs-TA experiments revealed that α-keto cations could be observed after excitation directly, which could easily produce the DMB through the addition of a hydroxyl within 8.7 ps. This work provides comprehensive photo-deactivation mechanisms of DMB fluoride in MeCN and aqueous conditions and provides critical insights regarding the biomedical application of DMB-based PRPG compounds.

11.
Chem Res Toxicol ; 37(2): 234-247, 2024 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-38232180

RESUMO

Human tissue three-dimensional (3D) organoid cultures have the potential to reproduce in vitro the physiological properties and cellular architecture of the organs from which they are derived. The ability of organoid cultures derived from human stomach, liver, kidney, and colon to metabolically activate three dietary carcinogens, aflatoxin B1 (AFB1), aristolochic acid I (AAI), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), was investigated. In each case, the response of a target tissue (liver for AFB1; kidney for AAI; colon for PhIP) was compared with that of a nontarget tissue (gastric). After treatment cell viabilities were measured, DNA damage response (DDR) was determined by Western blotting for p-p53, p21, p-CHK2, and γ-H2AX, and DNA adduct formation was quantified by mass spectrometry. Induction of the key xenobiotic-metabolizing enzymes (XMEs) CYP1A1, CYP1A2, CYP3A4, and NQO1 was assessed by qRT-PCR. We found that organoids from different tissues can activate AAI, AFB1, and PhIP. In some cases, this metabolic potential varied between tissues and between different cultures of the same tissue. Similarly, variations in the levels of expression of XMEs were observed. At comparable levels of cytotoxicity, organoids derived from tissues that are considered targets for these carcinogens had higher levels of adduct formation than a nontarget tissue.


Assuntos
Adutos de DNA , Neoplasias , Humanos , Carcinógenos/toxicidade , Carcinógenos/metabolismo , Fígado/metabolismo , Organoides/metabolismo
12.
Nat Commun ; 14(1): 6999, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37919292

RESUMO

The diamond potential of kimberlites is difficult to assess due to several mantle and magmatic processes affecting diamond content. Traditionally, initial evaluations are based on the compositions of mantle-derived minerals (garnet, chromite, clinopyroxene), which allow an assessment of pressure-temperature conditions and lithologies suitable for diamond formation. Here we explore a complementary approach that considers the conditions of diamonds destruction by interaction with melts/fluids (metasomatism). We test the hypothesis that carbonate-rich metasomatism related to kimberlite melt infiltration into the deep lithosphere is detrimental to diamond preservation. Our results show that high diamond grades in kimberlites worldwide are exclusively associated with high-Mg/Fe olivine, which corresponds to mantle lithosphere minimally affected by kimberlite-related metasomatism. Diamond dissolution in strongly metasomatised lithosphere containing low-Mg/Fe olivine provides a causal link to the empirical associations between low diamond grades, abundant Ti-Zr-rich garnets and kimberlites with high Ti and low Mg contents. This finding show-cases olivine geochemistry as a viable tool in diamond exploration.

13.
Sr Care Pharm ; 38(11): 452-456, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37885096

RESUMO

Senior care pharmacists are well-positioned to lead and drive antimicrobial stewardship (AMS) initiatives, not only through audit and data collection, but also through communication, collaboration, and cooperation with prescribers and nurses to influence prescribing behaviors. Senior care pharmacists are in a unique position to take a leadership role within the interprofessional team to achieve AMS goals. They should engage with the interprofessional team to promote the judicious and appropriate use of antimicrobials at their practice sites. This position statement is an update of the 2017 version by the American Society of Consultant Pharmacists (ASCP) Antimicrobial Stewardship and Infection and Prevention Control Committee and the Society of Infectious Diseases Pharmacists (SIDP).


Assuntos
Anti-Infecciosos , Gestão de Antimicrobianos , Doenças Transmissíveis , Humanos , Estados Unidos , Farmacêuticos , Consultores , Anti-Infecciosos/uso terapêutico , Doenças Transmissíveis/tratamento farmacológico
14.
J Biomech ; 159: 111776, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37683377

RESUMO

Undergraduate research is commonly performed in many STEM disciplines and has a wide array of benefits for students, laboratories, principal investigators, and institutions. While many fields have assessed best practices and the cost-benefit analysis of incorporating undergraduates in research, this has not yet been addressed in biomechanics. This paper represents the perspectives of seven members of the American Society of Biomechanics (ASB) Teaching Biomechanics Interest Group (TBIG). These TBIG members discussed their own experience regarding the opportunities, challenges, and benefits of undergraduate research and this perspective paper presents the commonalities found during these interactions. The TBIG members reported that undergraduate research was assessed similarly to graduate student research, which often led to an underestimation of productivity for both the student and overall lab output. While undergraduate researchers are not often responsible for publications and grant funding, they are instrumental in lab productivity in other ways, such as through human subject approvals, conference abstract presentations, student thesis projects, and more. Students benefit from these experiences, not necessarily by continuing in research, but by learning skills and making connections which further them in any career. While this perspective presents the experience of seven professors in the United States, future studies should further assess the cost-benefit relationship of working with undergraduates in biomechanics research on a global scale. A clearer picture of this analysis could benefit students, faculty, and administrators in making difficult decisions about lab productivity and assessment.


Assuntos
Aprendizagem , Estudantes , Humanos , Fenômenos Biomecânicos , Docentes
15.
J Phys Chem Lett ; 14(33): 7507-7512, 2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37581610

RESUMO

Blebbistatin was demonstrated as a promising two-photon near-infrared activated photoremovable protecting group of hydroxyl radicals with various potential applications. However, the photocleavage mechanism of the blebbistatin derivatives remains ambiguous. Herein, blebbistatin derivatives with various electronic characteristic leaving groups were synthesized and studied, and the photocleavage mechanism(s) and the tunable effect of the leaving groups were unveiled by combining photoproduct analysis, reactive oxygen radical species detection, femtosecond transient absorption spectroscopy, and density functional theory calculation. More substantial electron-withdrawing leaving groups facilitate heterolysis of the C-O bond, which results in a cationic intermediate and a corresponding remnant. Weaker electron-withdrawing groups lead to a higher proportion of homolysis of the C-O bond, accompanied by the generation of the reactive oxygen radical species. With this structure-property relationship, the protected groups of the molecules of interest can be rationally chosen to satisfy the different requirements needed for specific applications.

16.
J Appl Biomech ; 39(6): 370-376, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37491013

RESUMO

The hamstring plays an important role in reducing loads born by the anterior cruciate ligament. As anterior cruciate ligament injuries occur rapidly after ground contact, how the hamstring is activated prior to landing can influence injury risk. The purpose was to determine sex-related differences in hamstring activation immediately before landing and the effect of fatigue on "preactivation." Twenty-four participants (13 males and 11 females, age = 24.3 [6.5] y, mass = 72.2 [19.3] kg, height = 169 [9.7] cm) participated in this study. Participants completed a drop-vertical jump protocol before and after a lower body fatigue protocol. Hamstring electromyography (EMG) amplitude at 5 periods prior to landing, peak vertical ground reactions forces (in newtons/body weight), rate of loading (in body weight/second), and landing error scoring system were measured. Females had higher EMG amplitude before and after fatigue (P < .024), with decreased EMG amplitude for both sexes after fatigue (P = .025). There was no change on vertical ground reaction force, rate of loading, or landing error scoring system. Males and females demonstrated similar landing performance before and after fatigue but have different hamstring neuromuscular coordination strategies. The acute reduction in hamstring EMG amplitude following fatigue may increase loading on the anterior cruciate ligament.


Assuntos
Lesões do Ligamento Cruzado Anterior , Articulação do Joelho , Masculino , Humanos , Feminino , Adulto Jovem , Adulto , Articulação do Joelho/fisiologia , Músculo Esquelético/fisiologia , Eletromiografia , Ligamento Cruzado Anterior , Peso Corporal , Fenômenos Biomecânicos/fisiologia
17.
Psychogeriatrics ; 23(5): 821-830, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37438150

RESUMO

BACKGROUND: Promoting happiness has become increasingly important in old age for a wide range of reasons. In this study, we aim to examine the association between social inclusion (SI) and happiness among older adults in Ghana and identify the mediating factors. METHODS: The study included 1201 community-dwelling adults aged ≥50 (mean age = 66.4 ± SD 11.9 years; 63.3% female) from the 2016-2018 Ageing, Health, Psychological Well-being, and Health-seeking Behaviour Study. We assessed happiness with a self-rated and cross-culturally validated item on a five-point scale. SI was operationalised using the modified Berkman-Syme Social Network Index. The hypothesised associations were evaluated by hierarchical regressions and bootstrapping techniques from Hayes' PROCESS macro programme. RESULTS: The prevalence of happiness was 24.3% (all of the time), 43.6% (most of the time), 28.3% (little of the time), and 3.7% (none of the time). After controlling for potential confounders, higher SI was associated with increased levels of happiness (odds ratio (OR) = 1.36; 95% confidence interval (CI) = 1.16-2.51). Aside from family/friends contacts, all other SI domains positively influenced happiness (OR = 1.45-1.81). The link between SI and happiness was mediated by depressive symptoms (65.2%), generalised anxiety (30.1%), and sleep problems (9.5%). CONCLUSIONS: Our data suggest that psychological factors may largely explain the positive SI-happiness link. Efforts should target these factors to promote happiness in old age. Longitudinal analysis may confirm our findings.


Assuntos
Envelhecimento , Inclusão Social , Humanos , Feminino , Idoso , Masculino , Gana , Bem-Estar Psicológico , Felicidade
18.
Angew Chem Int Ed Engl ; 62(35): e202306890, 2023 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-37421410

RESUMO

Non-alternant topologies have attracted considerable attention due to their unique physiochemical characteristics in recent years. Here, three novel topological nanographenes molecular models of nitrogen-doped Stone-Thrower-Wales (S-T-W) defects were achieved through intramolecular direct arylation. Their chemical structures were unambiguously elucidated by single-crystal analysis. Among them, threefold intramolecular direct arylation compound (C42 H21 N) is the largest nanographene bearing a N-doped non-alternant topology to date, in which the non-benzenoid rings account for 83 % of the total molecular skeleton. The absorption maxima of this compound was located in the near-infrared region with a long tail up to 900 nm, which was much longer than those reported for similarly sized N-doped nanographene with six-membered rings (C40 H15 N). In addition, the electronic energy gaps of these series compounds clearly decreased with the introduction of non-alternant topologies (from 2.27 eV to 1.50 eV). It is noteworthy that C42 H21 N possesses such a low energy gap (Eg opt =1.40 eV; Eg cv =1.50 eV), yet is highly stable under ambient conditions. Our work reported herein demonstrates that the non-alternant topology could significantly influence the electronic configurations of nanocarbons, where the introduction of a non-alternanting topology may be an effective way to narrow the energy gap without extending the molecular π-conjugation.

19.
J Am Chem Soc ; 145(30): 16650-16657, 2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37478168

RESUMO

The realization of multifunctional nanoparticle systems is essential to achieve highly efficient catalytic materials for specific applications; however, their production remains quite challenging. They are typically achieved through the incorporation of multiple inorganic components; however, incorporation of functionality could also be achieved at the organic ligand layer. In this work, we demonstrate the generation of multifunctional nanoparticle catalysts using peptide-based ligands for tandem catalytic functionality. To this end, chimeric peptides were designed that incorporated a Au binding sequence and a catalytic sequence that can drive ester hydrolysis. Using this chimera, Au nanoparticles were prepared, which sufficiently presented the catalytic domain of the peptide to drive tandem catalytic processes occurring at the peptide ligand layer and the Au nanoparticle surface. This work represents unique pathways to achieve multifunctionality from nanoparticle systems tuned by both the inorganic and bio/organic components, which could be highly important for applications beyond catalysis, including theranostics, sensing, and energy technologies.


Assuntos
Ouro , Nanopartículas Metálicas , Ouro/química , Ligantes , Nanopartículas Metálicas/química , Peptídeos/química , Catálise
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