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1.
BMC Complement Med Ther ; 24(1): 313, 2024 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-39174985

RESUMEN

BACKGROUND: The current clinical management of carotid atherosclerosis is based on the control of risk factors and medicine. However, the risk of adverse events associated with the medicine resulting in concerns and low medication compliance makes it necessary to seek a safer alternative therapy. This study assessed the effectiveness and safety of acupuncture as a treatment for carotid atherosclerosis. METHODS: In this randomized controlled trial, patients with carotid atherosclerotic plaques were included and randomly assigned (1:1) to receive real acupuncture or sham acupuncture for 12 weeks. The follow-up period was 12 weeks. The primary outcome included carotid intima-media thickness (cIMT), plaque score (PS), plaque volume (PV) and grey-scale median (GSM). Secondary outcome was pulse wave velocity (PWV). Adverse events results were recorded as safety outcomes. RESULTS: From January 2021 to February 2022, 60 eligible patients were included. 55 patients (91.7%) completed the intervention and the 12-week follow-up and there was no statistical difference in demographics between the groups. At the end of treatment, the real acupuncture group had significantly reduced PS (P = 0.002), PV (P = 0.000), and improved GSM (P = 0.044). There was no significant difference in the reduction in cIMT (Left cIMT: P = 0.338, Right cIMT: P = 0.204) and PWV between the groups (the left BS: P = 0.429; the left ES: P = 0.701; the right BS: P = 0.211; the right ES: P = 0.083). Three mild adverse reactions occurred during the study. CONCLUSION: This study found that acupuncture had a certain effect on reducing the thickness and volume of carotid plaque and improving the stability of plaque with minor side effects. These findings suggest that acupuncture may be a potential alternative therapy for carotid atherosclerosis. TRIAL REGISTRATION: This trial has been registered at ClinicalTrials.gov (ChiCTR2100041762). Submitted 30 December 2020, Registered 4 January 2021 Prospectively registered.


Asunto(s)
Terapia por Acupuntura , Enfermedades de las Arterias Carótidas , Grosor Intima-Media Carotídeo , Humanos , Masculino , Femenino , Terapia por Acupuntura/métodos , Persona de Mediana Edad , Enfermedades de las Arterias Carótidas/terapia , Anciano , Resultado del Tratamiento , Análisis de la Onda del Pulso
2.
Langmuir ; 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38329721

RESUMEN

The coexistence of lead, zinc, and copper ions in wastewater constitutes an environmental challenge of pressing concern. This research delves into the preparation of innovative oxidation-doped conjugated microporous poly(aniline) frameworks, exploring their prospective efficacy in regulating lead ion adsorption from aqueous solutions. H2SO4-CMPTA demonstrates the capability to reach adsorption equilibrium within 15 min at a lead concentration of 50 ppm. Even at a lead concentration of 20 ppm, it still efficaciously attenuates these levels to sub-10 ppb, a value surpassing extant standard. H2SO4-CMPTA retains over 78.8% adsorption efficiency after six cycles. Analytical characterization coupled with computational calculations suggests that sulfate-coordinated nitrogen cationic structure plays a crucial role in adsorption. A deeper investigation reveals the cardinal role of electrostatic attraction and exclusive chelation adsorption underpinning the efficient capture of lead ions by doped sulfate ions. Intriguingly, in a mixed heavy metal solution containing lead, zinc, and copper ions, H2SO4-CMPTA exhibits an initial predilection toward zinc ions, yet an eventual ion-exchange adsorption gravitating toward lead ions was discerned, governed by the latter's superior binding energy. Our study elucidates a promising material as an efficacious tool for the remediation of aquatic environments tainted with lead contaminants.

3.
Iran J Kidney Dis ; 17(4): 191-198, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37634245

RESUMEN

INTRODUCTION: This study was conducted to determine the factors affecting the development of sarcopenias in elderly patients with chronic kidney disease (CKD), in order to provide future clinical reference and guidance in preventing the occurrence of sarcopenias in patients with CKD. METHODS: We included 116 CKD patients admitted to affiliated Hospital of Hebei University for retrospective analysis between September 2019 and March 2022. Fifty-one CKD patients with sarcopenias were selected as the observation group (OG) and 65 CKD patients without sarcopenias were considered as the control group (CG). Clinical baseline data such as age and sex were recorded, venous blood was collected for routine examination, and a multi-frequency body composition analyzer was applied to measure patients' body composition. Grip strength, middle arm circumstances (MAC) and triceps skin-fold thickness (TSF) were also measured. Then, patients' sleep quality, nutritional status and negative psychological status were assessed by using the Pittsburgh Sleep Quality Index (PSQI), Malnutrition inflammation score (MIS), and Self-rating Anxiety/Depression Scale (SAS/SDS), respectively. Differences in test results were compared inter-group, and the factors affecting the occurrence of sarcopenias in CKD patients were analyzed by multiple Logistic regression. RESULTS: OG patients were older than CG patients, with a higher number of female patients. Their BMI, bone mass, MAC, serum creatinine (Scr), uric acid (UA) and triglyceride (TG) were lower (P < .05). According to multiple Logistic regression analysis, age, as well as PSQI, MIS, SAS, and SDS scores were the risk factors for sarcopenias in CKD, while BMI, bone mass, MAC, Scr, UA and TG were protective factors (P < .05). CONCLUSION: Age, poor sleep quality, poor nutritional status and negative emotions are independent risk factors for sarcopenias in CKD patients, while BMI, bone mass, MAC, UA, TG, and Scr are independent protective factors.  DOI: 10.52547/ijkd.7537.


Asunto(s)
Sarcopenia , Anciano , Humanos , Femenino , Sarcopenia/diagnóstico , Sarcopenia/epidemiología , Estudios Retrospectivos , Composición Corporal , Densidad Ósea , Fuerza de la Mano , Inflamación
4.
Front Oncol ; 12: 938413, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35898876

RESUMEN

Objective: This study aimed to evaluate a convolution neural network algorithm for breast lesion detection with multi-center ABUS image data developed based on ABUS image and Yolo v5. Methods: A total of 741 cases with 2,538 volume data of ABUS examinations were analyzed, which were recruited from 7 hospitals between October 2016 and December 2020. A total of 452 volume data of 413 cases were used as internal validation data, and 2,086 volume data from 328 cases were used as external validation data. There were 1,178 breast lesions in 413 patients (161 malignant and 1,017 benign) and 1,936 lesions in 328 patients (57 malignant and 1,879 benign). The efficiency and accuracy of the algorithm were analyzed in detecting lesions with different allowable false positive values and lesion sizes, and the differences were compared and analyzed, which included the various indicators in internal validation and external validation data. Results: The study found that the algorithm had high sensitivity for all categories of lesions, even when using internal or external validation data. The overall detection rate of the algorithm was as high as 78.1 and 71.2% in the internal and external validation sets, respectively. The algorithm could detect more lesions with increasing nodule size (87.4% in ≥10 mm lesions but less than 50% in <10 mm). The detection rate of BI-RADS 4/5 lesions was higher than that of BI-RADS 3 or 2 (96.5% vs 79.7% vs 74.7% internal, 95.8% vs 74.7% vs 88.4% external). Furthermore, the detection performance was better for malignant nodules than benign (98.1% vs 74.9% internal, 98.2% vs 70.4% external). Conclusions: This algorithm showed good detection efficiency in the internal and external validation sets, especially for category 4/5 lesions and malignant lesions. However, there are still some deficiencies in detecting category 2 and 3 lesions and lesions smaller than 10 mm.

5.
Front Oncol ; 12: 1050288, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36620557

RESUMEN

Background: Stomach adenocarcinoma (STAD) arises from the mutations of stomach cells and has poor overall survival. Chemotherapy is commonly indicated for patients with stomach cancer following surgical resection. The most prevalent alteration that affects cancer growth is N6-methyladenosine methylation (m6A), although the possible function of m6A in STAD prognosis is not recognized. Method: The research measured predictive FRGs in BLCA samples from the TCGA and GEO datasets. Data on the stemness indices (mRNAsi), gene mutations, copy number variations (CNV), tumor mutation burden (TMB), and corresponding clinical characteristics were obtained from TCGA and GEO. STAD from TCGA and GEO at 24 m6A was investigated. Lasso regression was used to construct the prediction model to assess the m6A prognostic signals in STAD. In addition, the correlation between m6a and immune infiltration in STAD patients was discussed using GSVA and ssGSEA analysis. Based on these genes, GO and KEGG analyses were performed to identify key biological functions and key pathways. Result: A significant relationship was discovered between numerous m6A clusters and the tumor immune microenvironment, as well as three m6A alteration patterns with different clinical outcomes. Furthermore, GSVA and ssGSEA showed that m6A clusters were significantly associated with immune infiltration in the STAD. The low-m6Ascore group had a lower immunotherapeutic response than the high-m6Ascore group. ICIs therapy was more effective in the group with a higher m6Ascore. Three writers (VIRMA, ZC3H13, and METTL3) showed significantly lower expression, whereas five authors (METTL14, METTL16, WTAP, RBM15, and RBM15B) showed considerably higher expression. Three readers (YTHDC2, YTHDF2, and LRPPRC) had higher levels of expression, whereas eleven readers (YTHDC1, YTHDF1, YTHDF3, HNRNPC, FMR1, HNRNPA2B1, IGFBP1, IGFBP2, IGFBP3, and RBMX) had lower levels. As can be observed, the various types of m6 encoders have varied ramifications for STAD control. Conclusion: STAD occurrence and progression are linked to m6A-genes. Corresponding prognostic models help forecast the prognosis of STAD patients. m6A-genes and associated immune cell infiltration in the tumor microenvironment (TME) may serve as potential therapeutic targets in STAD, which requires further trials. In addition, the m6a-related gene signature offers a viable alternative to predict bladder cancer, and these m6A-genes show a prospective research area for STAD targeted treatment in the future.

6.
Biotechnol Biofuels ; 14(1): 174, 2021 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-34461979

RESUMEN

BACKGROUND: Isobutanol is an attractive biofuel with many advantages. Third-generation biorefineries that convert CO2 into bio-based fuels have drawn considerable attention due to their lower feedstock cost and more ecofriendly refining process. Although autotrophic cyanobacteria have been genetically modified for isobutanol biosynthesis, there is a lack of stable and convenient strategies to improve their production. RESULTS: In this study, we first engineered Synechococcus elongatus for isobutanol biosynthesis by introducing five exogenous enzymes, reaching a production titer of 0.126 g/L at day 20. It was then discovered that high salinity stress could result in a whopping fivefold increase in isobutanol production, with a maximal in-flask titer of 0.637 g/L at day 20. Metabolomics analysis revealed that high salinity stress substantially altered the metabolic profiles of the engineered S. elongatus. A major reason for the enhanced isobutanol production is the acceleration of lipid degradation under high salinity stress, which increases NADH. The NADH then participates in the engineered isobutanol-producing pathway. In addition, increased membrane permeability also contributed to the isobutanol production titer. A cultivation system was subsequently developed by mixing synthetic wastewater with seawater to grow the engineered cyanobacteria, reaching a similar isobutanol production titer as cultivation in the medium. CONCLUSIONS: High salinity stress on engineered cyanobacteria is a practical and feasible biotechnology to optimize isobutanol production. This biotechnology provides a cost-effective approach to biofuel production, and simultaneously recycles chemical nutrients from wastewater and seawater.

7.
Angew Chem Int Ed Engl ; 60(6): 2924-2928, 2021 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-33107179

RESUMEN

Synthetic routes for heteroatom-containing polycyclic aromatic hydrocarbons (H-PAHs) with alkyl and aryl substitution are demonstrated. Three H-PAHs, including heteroatom-containing rubicenes (H-rubicenes), angular-benzothiophenes (ABTs), and indenothiophene (IDTs) were successfully synthesized by two key steps, including polysubstituted olefin formation and cyclization. Specifically, ABT and H-rubicenes were comprehensively investigated by single-crystal X-ray diffraction, NMR spectroscopy, UV-vis absorption, cyclic voltammetry, transient absorption, and single-crystal OFET measurements.

8.
Angew Chem Int Ed Engl ; 59(35): 15043-15049, 2020 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-32385920

RESUMEN

Triplet acceptors have been developed to construct high-performance organic solar cells (OSCs) as the long lifetime and diffusion range of triplet excitons may dissociate into free charges instead of net recombination when the energy levels of the lowest triplet state (T1 ) are close to those of charge-transfer states (3 CT). The current triplet acceptors were designed by introducing heavy atoms to enhance the intersystem crossing, limiting their applications. Herein, two twisted acceptors without heavy atoms, analogues of Y6, constructed with large π-conjugated core and D-A structure, were confirmed to be triplet materials, leading to high-performance OSCs. The mechanism of triplet excitons were investigated to show that the twisted and D-A structures result in large spin-orbit coupling (SOC) and small energy gap between the singlet and triplet states, and thus efficient intersystem crossing. Moreover, the energy level of T1 is close to 3 CT, facilitating the split of triplet exciton to free charges.

9.
Angew Chem Int Ed Engl ; 59(31): 12756-12761, 2020 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-32343868

RESUMEN

Cancer possesses normoxic and hypoxia microenvironments with different levels of oxygen, needing different efficacies of photothermal and photodynamic therapies. It is important to precisely tune the photothermal and photodynamic effects of phototherapy nano-agents for efficient cancer treatment. Now, a series of copolymeric nanoparticles (PPy-Te NPs) were synthesized in situ by controlled oxidative copolymerization with different ratios of pyrrole to tellurophene by FeCl3 . The photothermal and photodynamic effects of semiconducting nano-agents under the first near-infrared (NIR) irradiation were precisely and systematically tuned upon simply varying the molar ratio of the pyrrole to tellurophene. The PPy-Te NPs were used for cancer treatment in mice, exhibiting excellent biocompatibility and therapeutic effect. This work presents a simple method to tune photothermal and photodynamic therapies effect in semiconducting nano-agents for cancer treatment.


Asunto(s)
Antineoplásicos/uso terapéutico , Nanopartículas/uso terapéutico , Neoplasias/tratamiento farmacológico , Fármacos Fotosensibilizantes/uso terapéutico , Polímeros/uso terapéutico , Pirroles/uso terapéutico , Animales , Antineoplásicos/síntesis química , Antineoplásicos/efectos de la radiación , Línea Celular Tumoral , Rayos Infrarrojos , Ratones , Nanopartículas/química , Nanopartículas/efectos de la radiación , Fotoquimioterapia , Fármacos Fotosensibilizantes/síntesis química , Fármacos Fotosensibilizantes/efectos de la radiación , Terapia Fototérmica , Polimerizacion , Polímeros/síntesis química , Polímeros/efectos de la radiación , Pirroles/síntesis química , Pirroles/efectos de la radiación , Especies Reactivas de Oxígeno/metabolismo
10.
Chemistry ; 26(55): 12510-12522, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32246541

RESUMEN

In recent decades, non-fullerene acceptors (NFAs) are undergoing rapid development and emerging as a hot area in the field of organic solar cells. Among the high-performance non-fullerene acceptors, aromatic diimide-based electron acceptors remain to be highly promising systems. This review discusses the important progress of perylene diimide (PDI)-based polymers as non-fullerene acceptors in all-polymer solar cells (all-PSCs) since 2014. The relationship between structure and property, matching aspects between donors and acceptors, and device fabrications are unveiled from a synthetic chemist perspective.

11.
Small ; 16(17): e2000909, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32249500

RESUMEN

Various organic nanoagents have been developed for photothermal therapy (PTT) and photodynamic therapy (PDT) under near-infrared (NIR) irradiation. Among them, small molecule-based nanoagents are very attractive due to their advantages of well-defined chemical structures, high purity, good reproducibility, and easy processability. However, only a few small molecule-based nanoagents have been developed for PDT under NIR irradiation. Moreover, the mechanism of PDT under NIR is still elusive. Herein, a semiconducting small molecule (BTA) with donor-acceptor-donor structure and twisted conformation is developed for PDT/PTT under NIR irradiation. A large π-conjugated electron-deficient unit is used as the core to couple with two electron-donating units, ensuring the strong absorption under 808 nm. Moreover, the donor-acceptor structures and twisted conformation can reduce the energy gap between the singlet and triplet states (∆EST ) to afford effective intersystem crossing, beneficial for reactive oxygen species generation. The mechanism is probed by experimental and theoretical evidence. Moreover, the BTA nanoparticles exhibit excellent biocompatibility and PTT/PDT in vitro performance under NIR irradiation. This provides a strategy for designing highly efficient PDT/PTT molecular materials.


Asunto(s)
Nanopartículas , Fotoquimioterapia , Terapia Fototérmica , Semiconductores , Rayos Infrarrojos , Fotoquimioterapia/métodos , Terapia Fototérmica/métodos
12.
Food Res Int ; 129: 108847, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32036922

RESUMEN

The rheological properties and microstructure of dairy gels involve the connectivity between milk fat globules (MFG) and casein micelles that is affected by technological processes such as milk homogenization and heat treatment. The underlying mechanisms require further quantification of the interactions at the nanoscale level to be fully understood and controlled. In this study, we examined the adhesion of homogenized MFG to milk proteins and evaluated the role of ultra-high temperature (UHT) heat treatment and pH. The combination of physico-chemical analysis, rheology and microscopy observations at different scale levels associated to atomic force microscopy (AFM) force spectroscopy were used. AFM experiments performed at the particle scale level showed that adhesion of individual homogenized MFG to milk proteins (1) is increased upon acidification at pH 4.5: 1.4 fold for unheated samples and 3.5 fold for UHT samples, and (2) is enhanced by about 1.7 fold at pH 4.5 after UHT heat treatment of milk, from 176 pN to 296 pN, thanks to highly-reactive heat-denatured whey proteins located at the surface of MFG and caseins. The increased inter-particle adhesion forces accounted for more connected structures and stiffer UHT milk acid gels, compared to unheated-milk gels. Using a multiscale approach, this study showed that heat treatment of milk markedly affected the interactions occurring at the particle's surface level with consequences on the bulk structural and rheological properties of acid gels. Such findings will be useful for manufacturers to modulate the texture of fermented dairy products through the tailoring of heat-induced complexation of proteins and the connectivity of homogenized MFG with the protein network. This work will also contribute in a better understanding of the impact of process-induced changes on the digestibility and metabolic fate of proteins and lipids.


Asunto(s)
Glucolípidos/química , Glicoproteínas/química , Calefacción , Gotas Lipídicas/química , Microscopía de Fuerza Atómica/métodos , Análisis Espectral/métodos , Proteína de Suero de Leche/química , Animales , Bovinos , Análisis de los Alimentos , Manipulación de Alimentos , Calor , Concentración de Iones de Hidrógeno
13.
Sci Bull (Beijing) ; 65(18): 1580-1586, 2020 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-36738076

RESUMEN

It is important to regulate the concentration of reactive oxygen species (ROS) in cells since they play important roles in metabolism. Thus, developing nanoreagents to control the ROS is critical. Herein, tellurium-doped carbon quantum dots (Te-CDs) were developed by a simple and efficient hydrothermal method, which can scavenge H2O2 to protect cells under ambient condition, but generate ·OH under 808 nm irradiation as photodynamic application. This contribution presented a kind of novel CDs with dual-functions, which can potentially regulate ROS under different conditions.

14.
Polymers (Basel) ; 11(11)2019 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-31652961

RESUMEN

Developing cheap, clean and atomic-efficient synthetic methodologies for conjugated polymers are always critical for the field of organic electronics. Herein, classic Ullmann coupling polymerization is developed to synthesize a series of Acceptor-Acceptor (A-A) type homopolymers with microwave-assistance, which are supported by nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF), elemental analysis (EA) and gel permeation chromatography (GPC). The physicochemical properties of these polymers are studied by UV-vis spectroscopy, cyclic voltammetry (CV), thermal gravimetric analysis (TGA), and density functional theory (DFT) calculation. Furthermore, these A-A homopolymers are used as acceptors for all-polymer solar cells (All-PSCs), affording a promising efficiency of 3.08%, which is the highest value for A-A-homopolymer-based organic solar cells.

15.
Colloids Surf B Biointerfaces ; 182: 110363, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31344611

RESUMEN

The surface of milk fat globules consists of a biological membrane rich in polar lipids and glycoproteins. However, high shear stress applied upon homogenization disrupts the membrane and leads to the adsorption of casein micelles, as the major protein fraction of milk. These changes in the interface properties could affect the interactions between native or homogenized milk fat globules and the surrounding protein matrix, at neutral pH and upon acidification. In this study, macroscale rheometry, microscopic observations, nanoscale AFM-based force spectroscopy and physico-chemical analysis were combined to examine the interfacial composition and structure of milk fat globules and to evaluate their interactions with casein micelles. We showed that the surface properties of milk fat globules (biological membrane vs. caseins) and pH govern their interactions with casein micelles. The adhesion between individual fat globules and casein micelles was higher upon homogenization, especially at acid pH where the work of adhesion increased from 3.3 x 10-18 to 14 x 10-18 J for native and homogenized fat globules, respectively. Consequently, casein-coated homogenized fat globules yield stiffer milk acid gels. These findings cast light on the importance of colloidal particle's surface properties and pH on their connectivity with the surrounding matrix, which modulates the bulk microstructure and rheological properties with potential functional consequences, such as milk lipid digestion.


Asunto(s)
Caseínas/química , Glucolípidos/química , Glicoproteínas/química , Leche/química , Animales , Geles , Concentración de Iones de Hidrógeno , Gotas Lipídicas , Micelas , Microscopía de Fuerza Atómica , Tamaño de la Partícula , Unión Proteica , Reología , Propiedades de Superficie
16.
Chemphyschem ; 20(20): 2600-2607, 2019 10 16.
Artículo en Inglés | MEDLINE | ID: mdl-31179624

RESUMEN

Tellurophene-based small molecules and polymers have received great attentions owing to their applications in thin-film transistors, solar cells, and sensors. This article reviews the current progress of the synthesis and applications of tellurophene-based small molecules and polymers. The physicochemical properties and optoelectronic applications of tellurophene-based materials are summarized and discussed. In the end, the challenges and outlook of tellurophene-based materials are presented.

17.
ACS Appl Mater Interfaces ; 11(19): 17884-17893, 2019 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-30998309

RESUMEN

Semiconducting polymer (SP) nanoparticles (NPs) have recently emerged as one of the most promising agents for photoacoustic imaging (PAI)-guided photothermal/photodynamic therapy (PTT/PDT). Herein, a triplet tellurophene-based SP (PNDI-2T) was synthesized with efficient tin-free direct heteroarylation polycondensation. The PNDI-2T NPs display remarkable near-infrared absorption and low cytotoxicity. In addition, PNDI-2T NPs can generate abundant reactive oxygen species (ROS) since tellurophene facilitates the intersystem crossing to generate triplet excited states. Remarkably, PNDI-2T NPs present a high photothermal conversion efficiency (η = 45%) and a high ROS yield (ΦΔ = 38.7%) under 808 nm laser irradiation. Furthermore, we showed that PNDI-2T NPs could be excellent PAI-guided PTT/PDT agents for cancer theranostics. This study provides a new route to developing highly efficient and low cytotoxic agents for PAI-guided PTT/PDT.


Asunto(s)
Nanopartículas/química , Fotoquimioterapia , Polímeros/farmacología , Nanomedicina Teranóstica , Proliferación Celular/efectos de los fármacos , Células HeLa , Humanos , Técnicas Fotoacústicas , Polímeros/química , Especies Reactivas de Oxígeno/química , Semiconductores , Telurio/química
18.
ACS Appl Mater Interfaces ; 10(34): 28812-28818, 2018 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-30080021

RESUMEN

Mother Nature is always the best source for scientists to draw inspiration. Herein, a three-dimensional perylene diimide (PDI)-based molecular acceptor was designed and synthesized, in which six PDI units form an "iris-like" structure upon connecting with the hexaphenylbenzene core. Interestingly, this molecule is the nonfullerene acceptor containing most PDI units, which can absorb solar light to exhibit excellent power conversion efficiency, much more efficient than the natural flowers. This contribution presents an interesting example of learning from Mother Nature to design novel materials for applications.

19.
Inorg Chem ; 57(15): 9266-9273, 2018 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-29989396

RESUMEN

The C═S double bonds in CS2 and thioketones were catalytically cleaved by Pd dimeric complexes [(N∧N)2Pd2(NO3)2](NO3)2 (N∧N, 2,2'-bipyridine, 4,4'-dimethylbipyridine or 4,4'-bis(trifluoromethyl)) at room temperature in one pot to afford CO2 and ketones, respectively, for the first time. The mechanisms were fully investigated by kinetic NMR, isotope-labeled experiments, in situ ESI-MS, and DFT calculations. The reaction is involved a hydrolytic desulfurization process to generate C═O double bonds and a trinuclear cluster, which plays a pivotal role in the catalytic cycle to regenerate the dimeric catalysts with HNO3. Furthermore, the electronic properties of catalyst ligands possess significant influence on reaction rates and kinetic parameters. At the same temperature, the reaction rate is consistent with the order of electronegativity of N∧N ligands (4,4'-bis(trifluoromethyl) > 2,2'-bipyridine > 4,4'-dimethylbipyridine). This homogeneous catalytic reaction features mild conditions, a broad substrate scope, and operational simplicity, affording insight into the mechanism of catalytic activation of carbon sulfur bonds.

20.
Sci Adv ; 3(7): e1602388, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28782016

RESUMEN

Femtosecond resolution electron scattering techniques are applied to resolve the first atomic-scale steps following absorption of a photon in the prototypical hybrid perovskite methylammonium lead iodide. Following above-gap photoexcitation, we directly resolve the transfer of energy from hot carriers to the lattice by recording changes in the mean square atomic displacements on 10-ps time scales. Measurements of the time-dependent pair distribution function show an unexpected broadening of the iodine-iodine correlation function while preserving the Pb-I distance. This indicates the formation of a rotationally disordered halide octahedral structure developing on picosecond time scales. This work shows the important role of light-induced structural deformations within the inorganic sublattice in elucidating the unique optoelectronic functionality exhibited by hybrid perovskites and provides new understanding of hot carrier-lattice interactions, which fundamentally determine solar cell efficiencies.

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