Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 82
Filtrar
1.
Chem Sci ; 15(14): 5163-5173, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38577356

RESUMEN

Organic photoluminescent macrocyclic hosts have been widely advanced in many fields. Phosphorescent hosts with the ability to bind organic guests have rarely been reported. Herein, acyclic cucurbituril modified with four carboxylic acids (ACB-COOH) is mined to present uncommon purely organic room-temperature phosphorescence (RTP) at 510 nm with a lifetime of 1.86 µs. Its RTP properties are significantly promoted with an extended lifetime up to 2.12 s and considerable quantum yield of 6.29% after assembly with a polyvinyl alcohol (PVA) matrix. By virtue of the intrinsic self-crimping configuration of ACB-COOH, organic guests, including fluorescence dyes (Rhodamine B (RhB) and Pyronin Y (PyY)) and a drug molecule (morphine (Mor)), could be fully encapsulated by ACB-COOH to attain energy transfer involving phosphorescent acyclic cucurbituril. Ultimately, as-prepared systems are successfully exploited to establish multicolor afterglow materials and visible sensing of morphine. As an expansion of phosphorescent acyclic cucurbituril, the host afterglow color can be readily regulated by attaching different aromatic sidewalls. This study develops the fabrication strategies and application scope of a supramolecular phosphorescent host and opens up a new direction for the manufacture of intelligent long-lived luminescent materials.

2.
Surg Endosc ; 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38622225

RESUMEN

BACKGROUND: Premenstrual syndrome (PMS) is a pathological condition characterized by a series of abnormal physical, psychological, and behavioral symptoms. We evaluated the effectiveness of laparoscopic sleeve gastrectomy (LSG) in the treatment of patients with obesity and PMS. METHODS: In this case-control study, 131 patients with obesity (BMI ≥ 27.5 kg/cm2) diagnosed with moderate-to-severe PMS from March 2018 to March 2022 were prospectively selected to undergo LSG or not at their own discretion. Participants self-reported their PMS severity using the Premenstrual Syndrome Screening Tool. Among them, 68 patients chose LSG surgery, and 63 control group patients were followed up without surgery. Data were recorded at baseline and at 3 months post-treatment. We used a multivariate analysis to assess the improvement in PMS symptoms and associated factors. RESULTS: Of the 131 patients with obesity and PMS, the improvement rate of PMS in the LSG group was 57.35% (n = 39), while the improvement rate of PMS in the control group was 25.40% (n = 16). Furthermore, our study revealed that surgery is an independent factor affecting the improvement of patients with PMS. Additionally, there was a correlation between alcohol use, T2DM and obesity-related metabolic diseases, and BMI with PMS. The changes in BMI, testosterone, and estradiol(E2) levels may also contribute to the improvement of patients with obesity and PMS. CONCLUSION: LSG can improve the management of obesity in patients with PMS to some extent. Changes in BMI, testosterone, and E2 may be indicative of improvement in patients with obesity and PMS.

3.
BMC Surg ; 24(1): 82, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38443901

RESUMEN

BACKGROUND: From year to year, the proportion of people living with overweight and obesity in China rises, along with the prevalence of diseases linked to obesity. Although bariatric surgery is gaining popularity, there are still several issues with its promotion compared to Western nations. Since less developed places in China are more widespread due to disparities in the development of different regions, there has been little exploration of the factors that might be related to acceptance of bariatric surgery in these regions. METHODS: Patients who visited the Department of Gastrointestinal Surgery at the North Sichuan Medical College Affiliated Hospital from 2018 to 2022 and had obesity or other relevant metabolic problems were surveyed using a questionnaire. The relationship between demographic factors, socioeconomic status, and acceptance of bariatric surgery was analyzed. RESULTS: Of 334 patients, 171 had bariatric surgery. BMI, education level, marriage history, medical insurance, family support, and a history of type 2 diabetes were all linked to having bariatric surgery, according to a univariate analysis. In a multivariate analysis, BMI (P = 0.02), education (P = 0.02), family support (P<0.001), medical insurance coverage (P<0.001), and history of type 2 diabetes (P = 0.004) were all positively associated with a willingness to have bariatric surgery. Among 163 non-bariatric patients with obesity, 15.3% were not opposed to surgery but preferred trying medication first, 54.6% leaned towards medical therapy, and 30% were hesitant. Additionally, a majority of patients (48.55%) often lacked adequate knowledge about weight reduction therapy. Age, height, gender, smoking, drinking, family history of type 2 diabetes, education, and marital status did not significantly differ (P > 0.05). CONCLUSIONS: Many patients are concerned about the safety of surgical treatment and the possibility of regaining weight. Due to the relatively high cost of bariatric surgery, they tend to choose medical treatment. To enhance the acceptance of bariatric surgery in underdeveloped regions of China, it is crucial to focus on disseminating knowledge about bariatric surgery, offer pertinent health education to the community, and foster support from patients' families. The government should pay more attention to obesity and provide support in the form of medical insurance.


Asunto(s)
Cirugía Bariátrica , Diabetes Mellitus Tipo 2 , Humanos , Obesidad/complicaciones , Obesidad/cirugía , Sobrepeso , China/epidemiología
4.
Obes Surg ; 34(4): 1257-1266, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38396260

RESUMEN

OBJECTIVE: Investigate the long-term protective effects of gastric bypass surgery on the kidneys of hypertensive obese rats to better understand the role of gastric bypass surgery in preventing renal injury in humans with hypertension and obesity. METHODS: Compare 6-week-old spontaneously hypertensive rats, including 30 Roux-en-Y gastric bypass (RYGB) and 30 sham operations. Body weight and blood pressure were monitored before and up to 12 months after the operation. Blood lipids, blood creatinine, and blood urea nitrogen were measured. Kidney pathology was assessed using HE staining, while renal fibrosis was observed via Masson staining. Inflammatory indicators were examined by ELISA. The expression of the NLRP3 gene in the kidney was measured using immunofluorescence and western blot, and the changes in key pathways including ASC/IL-1ß protein were verified. RESULTS: RYGB reduced the body weight of hypertensive obese rats and had a protective effect on blood pressure. Additionally, the bypass effectively mitigated renal inflammation and fibrosis. Moreover, RYGB modulated the expression of NLRP3 and prevented kidney damage via the ASC/IL-1 pathway. CONCLUSION: This study validates that RYGB effectively attains sustained blood pressure control in hypertensive obese rats and has a potential kidney-protective mechanism via the NLRP3-ASC/IL-1ß pathway.


Asunto(s)
Derivación Gástrica , Hipertensión , Obesidad Mórbida , Humanos , Ratas , Animales , Proteína con Dominio Pirina 3 de la Familia NLR , Obesidad Mórbida/cirugía , Obesidad/cirugía , Riñón
5.
World J Surg Oncol ; 22(1): 58, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38369496

RESUMEN

BACKGROUND/PURPOSE: This study compared the clinical efficacy and safety of laparoscopic versus open resection for hilar cholangiocarcinoma (HCCA) and analyzed potential prognostic factors. METHODS: The study included patients who underwent HCCA resection at our center from March 2012 to February 2022. Perioperative complications and postoperative prognosis were compared between the laparoscopic surgery (LS) and open surgery (OS) groups. RESULTS: After screening 313 HCCA patients, 68 patients were eligible for the study in the LS group (n = 40) and OS group (n = 28). Kaplan-Meier survival curve analysis revealed that overall survival > 2 years and 3-year disease-free survival (DFS) were more common in the LS than OS group, but the rate of 2-year DFS was lower in the LS group than OS group. Cox multivariate regression analysis revealed age (< 65 years), radical resection, and postoperative adjuvant therapy were associated with reduced risk of death (hazard ratio [HR] = 0.380, 95% confidence interval [CI] = 0.150-0.940, P = 0.036; HR = 0.080, 95% CI = 0.010-0.710, P = 0.024 and HR = 0.380, 95% CI = 0.150-0.960, P = 0.040), whereas preoperative biliary drainage was an independent factor associated with increased risk of death (HR = 2.810, 95% CI = 1.130-6.950, P = 0.026). Perineuronal invasion was identified as an independent risk factor affecting DFS (HR = 5.180, 95% CI = 1.170-22.960, P = 0.030). CONCLUSIONS: Compared with OS, laparoscopic HCCA resection does not significantly differ in terms of clinical efficacy. Age (<65 years), radical resection, and postoperative adjuvant therapy reduce the risk of death, and preoperative biliary drainage increases the risk of death.


Asunto(s)
Neoplasias de los Conductos Biliares , Colangiocarcinoma , Tumor de Klatskin , Laparoscopía , Humanos , Anciano , Tumor de Klatskin/cirugía , Tumor de Klatskin/patología , Estudios Retrospectivos , Neoplasias de los Conductos Biliares/patología , Resultado del Tratamiento , Pronóstico , Análisis de Supervivencia , Laparoscopía/efectos adversos , Colangiocarcinoma/patología
6.
Angew Chem Int Ed Engl ; 63(13): e202317740, 2024 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-38318927

RESUMEN

Plasmon-mediated electrocatalysis that rests on the ability of coupling localized surface plasmon resonance (LSPR) and electrochemical activation, emerges as an intriguing and booming area. However, its development seriously suffers from the entanglement between the photoelectronic and photothermal effects induced by the decay of plasmons, especially under the influence of applied potential. Herein, using LSPR-mediated CO2 reduction on Ag electrocatalyst as a model system, we quantitatively uncover the dominant photoelectronic effect on CO2 reduction reaction over a wide potential window, in contrast to the leading photothermal effect on H2 evolution reaction at relatively negative potentials. The excitation of LSPR selectively enhances the CO faradaic efficiency (17-fold at -0.6 VRHE ) and partial current density (100-fold at -0.6 VRHE ), suppressing the undesired H2 faradaic efficiency. Furthermore, in situ attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) reveals a plasmon-promoted formation of the bridge-bonded CO on Ag surface via a carbonyl-containing C1 intermediate. The present work demonstrates a deep mechanistic understanding of selective regulation of interfacial reactions by coupling plasmons and electrochemistry.

7.
JACS Au ; 4(1): 216-227, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38274263

RESUMEN

Aqueous supramolecular long-lived near-infrared (NIR) material is highly attractive but still remains great challenge. Herein, we report cucurbit[8]uril confinement-based secondary coassembly for achieving NIR phosphorescence energy transfer in water, which is fabricated from dicationic dodecyl-chain-bridged 4-(4-bromophenyl)-pyridine derivative (G), cucurbit[8]uril (CB[8]), and polyelectrolyte poly(4-styrene-sulfonic sodium) (PSS) via the hierarchical confinement strategy. As compared to the dumbbell-shaped G, the formation of unprecedented linear polypseudorotaxane G⊂CB[8] with nanofiber morphology engenders an emerging phosphorescent emission at 510 nm due to the macrocyclic confinement effect. Moreover, benefiting from the following secondary assembly confinement, such tight polypseudorotaxane G⊂CB[8] can further assemble with anionic polyelectrolyte PSS to yield uniform spherical nanoparticle, thereby significantly strengthening phosphorescence performance with an extended lifetime (i.e., 2.39 ms, c.f., 45.0 µs). Subsequently, the organic dye Rhodamine 800 serving as energy acceptor can be slightly doped into the polyelectrolyte assembly, which enables the occurrence of efficient phosphorescence energy transfer process with efficiency up to 80.1% at a high donor/acceptor ratio, and concurrently endows the final system with red-shifted and long-lived NIR emission (710 nm). Ultimately, the as-prepared assembly is successfully exploited as versatile imaging agent for NIR window labeling and detecting in living cells.

8.
Small ; 20(7): e2305817, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37814379

RESUMEN

Complete ethanol oxidation reaction (EOR) in C1 pathway with 12 transferred electrons is highly desirable yet challenging in direct ethanol fuel cells. Herein, PtRh jagged nanowires synthesized via a simple wet-chemical approach exhibit exceptional EOR mass activity of 1.63 A mgPt-1 and specific activity of 4.07 mA cm-2 , 3.62-fold and 4.28-folds increments relative to Pt/C, respectively. High proportions of 69.33% and 73.42% of initial activity are also retained after chronoamperometric test (80 000 s) and 1500 consecutive potential cycles, respectively. More importantly, it is found that PtRh jagged nanowires possess superb anti-CO poisoning capability. Combining X-ray absorption spectroscopy, X-ray photoelectron spectroscopy as well as density functional theory calculations unveil that the remarkable catalytic activity and CO tolerance stem from both the Rh-induced electronic effect and geometric effect (manifested by shortened Pt─Pt bond length and shrinkage of lattice constants), which facilitates EOR catalysis in C1 pathway and improves reaction kinetics by reducing energy barriers of rate-determining steps (such as *CO → *COOH). The C1 pathway efficiency of PtRh jagged nanowires is further verified by the high intensity of CO2 relative to CH3 COOH/CH3 CHO in infrared reflection absorption spectroscopy.

9.
Nat Rev Chem ; 7(12): 854-874, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37993737

RESUMEN

Phosphorescence energy transfer systems have been applied in encryption, biomedical imaging and chemical sensing. These systems exhibit ultra-large Stokes shifts, high quantum yields and are colour-tuneable with long-wavelength afterglow fluorescence (particularly in the near-infrared) under ambient conditions. This review discusses triplet-to-singlet PRET or triplet-to-singlet-to-singlet cascaded PRET systems based on macrocyclic or assembly-confined purely organic phosphorescence introducing the critical toles of supramolecular noncovalent interactions in the process. These interactions promote intersystem crossing, restricting the motion of phosphors, minimizing non-radiative decay and organizing donor-acceptor pairs in close proximity. We discuss the applications of these systems and focus on the challenges ahead in facilitating their further development.

10.
Small ; 19(46): e2304009, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37442787

RESUMEN

Macrocyclic confinement-induced supramolecular luminescence materials have important application value in the fields of bio-sensing, cell imaging, and information anti-counterfeiting. Herein, a tunable multicolor lanthanide supramolecular assembly with white light emission is reported, which is constructed by co-assembly of cucurbit[7]uril (CB[7]) encapsulating naphthylimidazolium dicarboxylic acid (G1 )/Ln (Eu3+ /Tb3+ ) complex and carbon quantum dots (CD). Benefiting from the macrocyclic confinement effect of CB[7], the supramolecular assembly not only extends the fluorescence intensity of the lanthanide complex G1 /Tb3+ by 36 times, but also increases the quantum yield by 28 times and the fluorescence lifetime by 12 times. Furthermore, the CB[7]/G1 /Ln assembly can further co-assemble with CD and diarylethene derivatives (DAE) to realize the intelligently-regulated full-color spectrum including white light, which results from the competitive encapsulation of adamantylamine and CB[7], the change of pH, and photochromic DAE. The multi-level logic gate based on lanthanide supramolecular assembly is successfully applied in anti-counterfeiting system and information storage, providing an effective method for the research of new luminescent intelligent materials.

11.
Chem Sci ; 14(23): 6457-6466, 2023 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-37325139

RESUMEN

A photo-responsive full-color lanthanide supramolecular switch was constructed from a synthetic 2,6-pyridine dicarboxylic acid (DPA)-modified pillar[5]arene (H) complexing with lanthanide ion (Ln3+ = Tb3+ and Eu3+) and dicationic diarylethene derivative (G1) through a noncovalent supramolecular assembly. Benefiting from the strong complexation between DPA and Ln3+ with a 3 : 1 stoichiometric ratio, the supramolecular complex H/Ln3+ presented an emerging lanthanide emission in the aqueous and organic phase. Subsequently, a network supramolecular polymer was formed by H/Ln3+ further encapsulating dicationic G1via the hydrophobic cavity of pillar[5]arene, which greatly contributed to the increased emission intensity and lifetime, and also resulted in the formation of a lanthanide supramolecular light switch. Moreover, full-color luminescence, especially white light emission, was achieved in aqueous (CIE: 0.31, 0.32) and dichloromethane (CIE: 0.31, 0.33) solutions by the adjustment of different ratios of Tb3+ and Eu3+. Notably, the photo-reversible luminescence properties of the assembly were tuned via alternant UV/vis light irradiation due to the conformation-dependent photochromic energy transfer between the lanthanide and the open/closed-ring of diarylethene. Ultimately, the prepared lanthanide supramolecular switch was successfully applied to anti-counterfeiting through the use of intelligent multicolored writing inks, and presents new opportunities for the design of advanced stimuli-responsive on-demand color tuning with lanthanide luminescent materials.

12.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 39(6): 558-563, 2023 Jun.
Artículo en Chino | MEDLINE | ID: mdl-37340925

RESUMEN

Group 3 innate lymphoid cells (ILC3) are an ILC subset that is characterized by the expression of retinoic acid-related orphan nuclear receptor γt (RORγt) and interleukin 22 (IL-22). This review summarizes the role of ILC3 in coordinating innate immunity and adaptive immunity based on current research and elaborate the significance of ILC3 from the perspective of immune system evolution. In addition, based on immune-related functions, we propose a possible time when ILC3 appears in the evolution of the immune system. And then, the research limitations and prospects are discussed.


Asunto(s)
Inmunidad Innata , Linfocitos , Tretinoina
13.
J Chem Phys ; 158(17)2023 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-37125721

RESUMEN

A wide spectrum of state-of-the-art characterization techniques have been devised to monitor the electrode-electrolyte interface that dictates the performance of electrochemical devices. However, coupling multiple characterization techniques to realize in situ multidimensional analysis of electrochemical interfaces remains a challenge. Herein, we presented a hyphenated differential electrochemical mass spectrometry and attenuated total reflection surface enhanced infrared absorption spectroscopy analytical method via a specially designed electrochemical cell that enables a simultaneous detection of deposited and volatile interface species under electrochemical reaction conditions, especially suitable for non-aqueous, electrolyte-based energy devices. As a proof of concept, we demonstrated the capability of the homemade setup and obtained the valuable reaction mechanisms, by taking the tantalizing reactions in non-aqueous lithium-ion batteries (i.e., oxidation and reduction processes of carbonate-based electrolytes on Li1+xNi0.8Mn0.1Co0.1O2 and graphite surfaces) and lithium-oxygen batteries (i.e., reversibility of the oxygen reaction) as model reactions. Overall, we believe that the coupled and complementary techniques reported here will provide important insights into the interfacial electrochemistry of energy storage materials (i.e., in situ, multi-dimensional information in one single experiment) and generate much interest in the electrochemistry community and beyond.

14.
Chem Commun (Camb) ; 59(11): 1457-1460, 2023 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-36644902

RESUMEN

An injectable polysaccharide supramolecular hydrogel was successfully fabricated from opened D-glucopyranosyl ß-cyclodextrin with four aldehyde groups (ACD) cross-linked with biomacromolecule chitosan (CS), which was not only beneficial to the clustering-triggered emission of CS with high quantum yield (32.25%), but also could co-assemble with a first stage acceptor triphenylamine derivative (TPA) and encapsulate Cyanine 5 (Cy5) or Nile blue (NiB) achieving supramolecular cascade energy transfer from the cross-linked polymer to the dyes, leading to fluorescence emission at 673 nm or 680 nm, and could be further applied in cell imaging.

15.
Angew Chem Int Ed Engl ; 62(9): e202216083, 2023 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-36594790

RESUMEN

The electro-reforming of glycerol is an emerging technology of simultaneous hydrogen production and biomass valorization. However, its complex reaction network and limited catalyst tunability restrict the precise steering toward high selectivity. Herein, we incorporated the chelating phenanthrolines into the bulk nickel hydroxide and tuned the electronic properties by installing functional groups, yielding tunable selectivity toward formate (max 92.7 %) and oxalate (max 45.3 %) with almost linear correlation with the Hammett parameters. Further combinatory study of intermediate analysis and various spectroscopic techniques revealed the electronic effect of tailoring the valence band that balances between C-C cleavage and oxidation through the key glycolaldehyde intermediate. A two-electrode electro-reforming setup using the 5-nitro-1,10-phenanthroline-nickel hydroxide catalyst was further established to convert crude glycerol into pure H2 and isolable sodium oxalate with high efficiency.

16.
J Phys Chem Lett ; 13(48): 11288-11294, 2022 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-36449387

RESUMEN

Ethanol, as a sustainable biomass fuel, is endowed with the merits of theoretically high energy density and environmental friendliness yet suffers from sluggish kinetics and low selectivity toward the desired complete electrooxidation (C1 pathway). Here, the localized surface plasmon resonance (LSPR) effect is explored as a manipulating knob to boost electrocatalytic ethanol oxidation reaction in alkaline media under ambient conditions by appropriate visible light. Under illumination, Au@Pt nanoparticles with plasmonic core and active shell exhibit concurrently higher activity (from 2.30 to 4.05 A mgPt-1 at 0.8 V vs RHE) and C1 selectivity (from 9 to 38% at 0.8 V). In situ attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) provides a molecular level insight into the LSPR promoted C-C bond cleavage and the subsequent CO oxidation. This work not only extends the methodology hyphenating plasmonic electrocatalysis and in situ surface IR spectroscopy but also presents a promising approach for tuning complex reaction pathways.

17.
J Phys Chem Lett ; 13(39): 9079-9084, 2022 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-36154129

RESUMEN

In situ spectroscopic characterization of the interfacial structure of an organic additive at a Cu electrode is essential for a mechanistic understanding of Cu superfilling at the molecular level. In this work, we demonstrate wide-frequency attenuated total reflection surface-enhanced infrared absorption spectroscopy (wf-ATR-SEIRAS) to elucidate the dissociative adsorption of bis(sodium sulfopropyl)-disulfide (a typical accelerator) on a Cu electrode in conjunction with the electrochemical quartz crystal microbalance measurement and modeling calculations. The wf-ATR-SEIRAS clearly identifies the peaks featuring the sulfonate and methylene groups as well as the C-Ssulfonate and C-Sthiol vibrations of the adsorbate. Analysis of relative peak intensities from 1100 to 650 cm-1 reveals a more tilted alkyl chain axis for the thiolate on Cu than that on Au, which is supported by comparative density functional theory calculations. This work opens a new avenue for the wf-ATR-SEIRAS to study interfacial structures of electroplating additives related to advanced microelectronics manufacture.

18.
Angew Chem Int Ed Engl ; 61(44): e202213097, 2022 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-36094757

RESUMEN

Herein, we reported solid supramolecular bromonaphthylpyridinium polymers (P-BrNp), which exhibit tunable phosphorescence emission in the amorphous state enabled by sulfobutylether-ß-cyclodextrin (SBE-ß-CD) and diarylethene derivatives. The monomer BrNp gave single fluorescence emission at 490 nm, while an apparent room-temperature phosphorescence (RTP) at 550 nm emerged for P-BrNp copolymers with various feed ratios. Through fluorescence-phosphorescence dual emission, P-BrNp-0.1 displayed an ultrahigh white-light emission quantum yield of 83.9 %. Moreover, the subsequent assembly with SBE-ß-CD further enhanced the phosphorescent quantum yield of P-BrNp-0.1 from 64.1 % to 71.3 %, accompanied by the conversion of photoluminescence emission from white to yellow. Diarylethene monomers were introduced as photoswitches to realize reversible RTP emission, which can be used in switchable data encryption and multifunctional writing ink.

19.
Anal Chem ; 94(32): 11337-11344, 2022 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-35930311

RESUMEN

A balanced detection of both adsorbates and dissolved species is very important for the clarification of the electrochemical reaction mechanism yet remains a major challenge for different modes of electrochemical infrared (IR) spectroscopy. Among others, conventional attenuated total reflection-surface-enhanced IR absorption spectroscopy (ATR-SEIRAS) is far less sensitive to low-concentration solution species than to surface species. We report herein an electrochemical wide-frequency ATR-SEIRAS with a novel thin-layer flow cell design, fulfilling the simultaneous detection of the variations of surface and solution species. This setup consists of a silicon wafer (with one side micromachined and the other side metallized), a thin-layer electrolyte structure with tunable thickness and flow rate, and a tilt-correction system based on laser collimation, enabling a well-controlled mass transport within the electrolyte layer and the spectral differentiation of solution species from adsorbates. Using acidic methanol oxidation on a Pt film electrode as a model system, besides SEIRA bands for adsorbed CO and formate intermediates, IR spectral signals for dissolved products CO2, formic acid, and methyl formate can be readily identified for a quiescent electrolyte layer of ∼20 µm, which are otherwise undetected with conventional ATR-SEIRAS, as indicated by the trend of spectral features with increasing thickness or flow rate.


Asunto(s)
Electrólitos , Electroquímica , Electrodos , Espectrofotometría Infrarroja/métodos , Propiedades de Superficie
20.
Adv Sci (Weinh) ; 9(22): e2201523, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35652258

RESUMEN

A two-step sequential phosphorescence harvesting system with ultralarge Stokes shift and near-infrared (NIR) emission at 825 nm is successfully constructed by racemic 1,2-diaminocyclohexan-derived 6-bromoisoquinoline (BQ), cucurbit[8]uril (CB[8]), and amphipathic sulfonatocalix[4]arene (SC4AD) via cascaded assembly strategy in aqueous solution. In virtue of the confinement effect of CB[8] with rigid cavity, BQ can generate an emerging phosphorescent emission at 555 nm. Subsequently, the binary BQ⊂CB[8] further assemblies with SC4AD to form close-packed spherical aggregate, which contributes to the dramatic enhancement of phosphorescence emission intensity ≈30 times with prolonged lifetime from 21.3 µs to 0.364 ms. Notably, the BQ⊂CB[8]@SC4AD assembly can serve as an energy donor to conduct stepwise phosphorescence harvesting process through successive introduction of primary acceptors, cyanine 5 (Cy5) or nile blue (NiB), and secondary acceptor, heptamethine cyanine (IR780). The final aggregate with remarkable ultralarge Stokes shift (≈525 nm) and long-lived NIR photoluminescence (PL) emission at 825 nm is further employed as imaging agent for NIR cell labeling.


Asunto(s)
Rayos Infrarrojos , Radiación
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...