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1.
Biomater Sci ; 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38727636

RESUMEN

Chronic non-healing wounds are a common consequence of skin ulceration in diabetic patients, with severe cases such as diabetic foot even leading to amputations. The interplay between pathological factors like hypoxia-ischemia, chronic inflammation, bacterial infection, impaired angiogenesis, and accumulation of advanced glycosylation end products (AGEs), resulting from the dysregulation of the immune microenvironment caused by hyperglycemia, establishes an unending cycle that hampers wound healing. However, there remains a dearth of sufficient and effective approaches to break this vicious cycle within the complex immune microenvironment. Consequently, numerous scholars have directed their research efforts towards addressing chronic diabetic wound repair. In recent years, gases including Oxygen (O2), Nitric oxide (NO), Hydrogen (H2), Hydrogen sulfide (H2S), Ozone (O3), Carbon monoxide (CO) and Nitrous oxide (N2O), along with gas-releasing materials associated with them have emerged as promising therapeutic solutions due to their ability to regulate angiogenesis, intracellular oxygenation levels, exhibit antibacterial and anti-inflammatory effects while effectively minimizing drug residue-induced damage and circumventing drug resistance issues. In this review, we discuss the latest advances in the mechanisms of action and treatment of these gases and related gas-releasing materials in diabetic wound repair. We hope that this review can provide different ideas for the future design and application of gas therapy for chronic diabetic wounds.

2.
ACS Appl Mater Interfaces ; 16(15): 18608-18626, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38565551

RESUMEN

Hypoxia, chronic inflammation, and elevated reactive oxygen species (ROS) production induced by hyperglycemia pose formidable challenges to the healing of diabetic chronic wounds, often resulting in impaired recovery. Currently, sustainable and eco-friendly therapeutic approaches targeting this multifaceted problem remain uncharted. Herein, we develop a unique three-functional covalent organic framework (COF)-modified microalgae gel designed for the preparation and treatment of chronic diabetic wounds. The gel comprises an oxygen-releasing basic fibroblast growth factor (bFGF) microalgae matrix, augmented by an ROS-responsive COF. Although two of these components have been reported to be used in wound healing, the combination of all three functions represents an innovative approach to synergize the treatment of chronic diabetic wounds. Therefore, we propose a new concept of "ligand interlocking" with three functional synergistic effects. Specifically, the COF has a similar effect to the "double Excalibur", which binds bFGF to promote angiogenesis and proliferation and inhibit the inflammatory response of chronic wounds and binds live microalgae to eliminate ROS and release dissolved oxygen to alleviate the hypoxia of wounds. Moreover, in vivo experiments and RNA sequencing analyses similarly demonstrated that the COF-modified microalgae gel reduced the inflammatory cascade cycle in the wound site and promoted vascular and tissue regeneration. We posit that the COF-modified microalgae gel represents a promising strategy for the active in vivo delivery of therapeutics to the wound body in intensive care unit settings.


Asunto(s)
Diabetes Mellitus , Estructuras Metalorgánicas , Microalgas , Humanos , Factor 2 de Crecimiento de Fibroblastos , Especies Reactivas de Oxígeno , Geles , Hipoxia , Oxígeno , Hidrogeles
4.
Eur J Obstet Gynecol Reprod Biol ; 291: 34-38, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37813004

RESUMEN

Polyhydramnios can be caused by genetic defects at times. However, to establish an accurate diagnosis and provide a precise prenatal consultation in a given case is still a great challenge toward obstetricians. To uncover the genetic cause of polyhydramnios in the two consecutive pregnancies, we performed whole-exome sequencing of DNA for the second suffering fetuses, their parents, and targeted sanger sequencing of other members of this family. We discovered a hemizygous truncating variant in MTM1 gene, c.438_439 del (p. H146Q fs*10) in this Chinese family. In the light of the molecular discoveries, the fetus's clinical phenotype was considered to be a good fit for X-linked myotubular myopathy (XLMTM). There is no related research to the prenatal manifestations of MTM1-related XLMTM among Chinese population, and this is the first one to present. Though the etiology of polyhydramnios is complicated, WES may provide us with a creative avenue in prenatal diagnosis.


Asunto(s)
Miopatías Estructurales Congénitas , Polihidramnios , Embarazo , Femenino , Humanos , Secuenciación del Exoma , Polihidramnios/diagnóstico por imagen , Polihidramnios/genética , Proteínas Tirosina Fosfatasas no Receptoras/genética , Mutación , Miopatías Estructurales Congénitas/diagnóstico , Miopatías Estructurales Congénitas/genética , Miopatías Estructurales Congénitas/patología
5.
J Matern Fetal Neonatal Med ; 36(2): 2266545, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37821354

RESUMEN

OBJECTIVE: To evaluate the value of transvaginal ultrasound parameters before and after cerclage in twins in predicting spontaneous preterm birth (sPTB) before 28+0 weeks. METHODS: We retrospectively studied the medical records of twin-pregnant women who underwent ultrasound-indicated cerclage between January 2016 and February 2022 at our hospital. Recorded transvaginal ultrasound images before and after cerclage were reassessed for cervical length (CL), uterocervical angle (UCA), funneling, and sludge. Multivariate logistic and Cox regression analyses were performed to identify the independent risk factors associated with sPTB before 28 weeks. RESULTS: A total of 69 women were included. Among them, 17 women (24.64%) delivered before 28 weeks of age. Regression analysis revealed a significant association of post-cerclage CL, UCA, white blood cell (WBC) count, and gestational age (GA) at cerclage with sPTB before 28 weeks. The area under the curve of these predictors was 0.938 (95% confidence interval, 0.882-0.994; p < .001), with a sensitivity of 88.2%, specificity of 92.3%, positive predictive value of 78.9%, and negative predictive value of 96.0%. Cox analysis showed that post-cerclage UCA was an independent risk factor affecting the cerclage-to-delivery interval (hazard ratios, 1.026; 95% confidence interval (CI), 1.004-1.048; p = .019). CONCLUSIONS: The combination of post-cerclage CL, UCA, WBC count, and GA at cerclage showed good performance in predicting sPTB at <28 weeks in twin pregnancy. Post-cerclage UCA is also associated with pregnancy latency. We found that post-cerclage cervical ultrasound may be useful to predict preterm birth before 28 weeks in twins who undergo ultrasound-indicated cerclage.


Asunto(s)
Cerclaje Cervical , Cuello del Útero , Nacimiento Prematuro , Ultrasonografía Prenatal , Femenino , Humanos , Recién Nacido , Embarazo , Medición de Longitud Cervical , Cuello del Útero/diagnóstico por imagen , Cuello del Útero/cirugía , Embarazo Gemelar , Nacimiento Prematuro/diagnóstico por imagen , Nacimiento Prematuro/etiología , Nacimiento Prematuro/prevención & control , Estudios Retrospectivos , Ultrasonografía Prenatal/métodos
6.
Z Orthop Unfall ; 2023 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-37739012

RESUMEN

This study aimed to evaluate the safety and efficacy of delayed reconstruction of the perforator pedicle propeller flap after the induced membrane technique in the treatment of Gustilo IIIB open distal tibial fracture, and to evaluate the clinical outcome and complications of two different perforator pedicle propeller flaps.Thirty-four patients with Gustilo IIIB open distal tibial fractures treated by the induced membrane technique and delayed reconstruction of two different perforator pedicle propeller flaps from May 2017 to March 2022 were retrospectively analyzed. Patients were divided into two groups according to the different kinds of perforator pedicle propeller flaps covered. The operation required two stages. The Radiographic Union Score for Tibial fractures (RUST) was used to evaluate the healing of the tibial bone defect. The American Orthopaedic Foot and Ankle Society (AOFAS) score was used to evaluate ankle function. The complications associated with the technique were recorded.The number of serial debridements, excluding those performed during emergency and final operations, was a mean of 2.28 ± 0.83 in the PAPF group. The PAPF group had a mean bone defect length of 6.76 ± 0.69 cm, the median healing time of 13.11 ± 0.96 months, RUST score 12.68 ± 1.63, and AOFAS score of 84.12 ± 6.38. On the other hand the PTAPF group's mean bone defect length was 6.73 ± 0.95 cm, the median healing time 12.63 ± 1.46 months, RUST score 13.73 ± 1.53 and AOFAS score 82.79 ± 5.49. There were no observed significant differences the two groups in the number of serial debridements, bone defect length, bone union time, RUST score, or AOFAS score (p > 0.05). Flap size ranged from 9 × 6 cm2 to 14 × 7 cm2 in the PAPF group and from 9 × 6 cm2 to 13 × 7 cm2 in the PTAPF group. There were no severe complications such as flap-related complications or amputation. The differences in complications in the two groups were not statistically significant.In cases of severe open tibial fracture, the reconstructive method is important. When delayed reconstruction is inevitable, surgeons should first perform radical debridement, followed by vacuum sealing drainage as a bridging therapy; both PAPF and PTAPF can be considered for definitive soft tissue coverage.

7.
Heliyon ; 9(6): e16980, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37484232

RESUMEN

Objective: To explore the relationship between Tuberous sclerosis complex (TSC) and cardiac tumors at our institution over the past five years and to evaluate the value of imaging technologies and genetic testing in the prenatal diagnosis of TSC. Methods: Fetal echocardiography (FE) was performed in the whole population between 2016 and 2020. Fetuses detected with cardiac tumor(s) were included. Fetal cranial magnetic resonance imaging (MRI) and gene mutation tests were further examined. Those who declined genetic testing were excluded in the final analysis. Results: A total of 40 fetuses were included in our study. There were 27 cases performed cranial magnetic resonance imaging (MRI) and the rest of 13 cases refused. Among 10 fetuses with cranial lesions detected by MRI, all of them were eventually diagnosed with TSC. And for 17 fetuses without cranial lesions, none of them were identified with a pathogenic variation in gene TSC1/2. The prevalence of TSC was significantly higher in the multiple tumors group than in the solitary group (9/20 vs. 2/20, P = 0.034). 11 fetuses had TSC1 (n = 3) or TSC2 (n = 8) causative or suspected causative mutations, of which 9 were sporadic mutations and 2 were familial mutations. Conclusion: Fetal cranial MRI should be recommended to evaluate brain lesions, and genetic mutation should be examined, if possible, especially for those with multiple heart tumors. When typical cardiac tumors and cranial lesions are detected, the diagnosis of TSC can almost be made even without genetic mutation results.

8.
Heliyon ; 8(10): e10731, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36247114

RESUMEN

Objective: To develop a nomogram to predict preterm birth before 28 weeks in pregnant women undergoing cervical cerclage. Study design: We retrospectively studied the medical records on pregnant women who underwent cervical cerclage in January 2016 to September 2020. We developed the model from a development cohort in Women's Hospital, Zhejiang university, School of medicine, which randomly divided by 7:3 into training cohort for nomogram development, and internal validation cohort to confirm the model's performance. We then tested the nomogram in an external validation cohort over a similar period. The Harrell's C-index, calibration curve, decision curve analyses (DCA) were performed to assess the model. Results: 528 patients formed the development cohort, and 97 patients formed the external validation cohort. The model initially incorporated 10 baseline variables, while 5 variables were estimated in the nomogram at last: history of prior second-trimester loss, use of in-vitro fertilization (IVF), cervical dilation at cerclage, C-reactive protein (CRP) and platelet-lymphocyte ratio (PLR). The nomogram achieved good concordance indexes of 0.82(95%CI 0.77-0.88), 0.80(95%CI 0.72-0.88) and 0.79 (95%CI 0.68-0.90) in the training, internal and external validation cohort, respectively. And the nomogram had well-fitted calibration curves. Decision curve analysis demonstrated that the nomogram was clinically useful. Conclusions: The well-performed nomogram graphically represents the risk factors and a pre-operative predicted model in predicting the risk of preterm birth at <28 weeks in singleton pregnant women undergoing cervical cerclage. The model can provide a useful guide for clinicians and patients in making appropriate clinical decisions.

9.
Sci Rep ; 12(1): 3691, 2022 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-35256677

RESUMEN

The first-principles calculations based on density functional theory with projector-augmented wave are used to study the anisotropy of elastic modulus, mechanical hardness, minimum thermal conductivity, acoustic velocity and thermal expansion of magnesite (MgCO3) under deep mantle pressure. The calculation results of the phase transition pressure, equation of state, elastic constants, elastic moduli, elastic wave velocities and thermal expansion coefficient are consistent with those determined experimentally. The research results show that the elastic moduli have strong anisotropy, the mechanical hardness gradually softens with increasing pressure, the conduction velocity of heat in the [100] direction is faster than that in the [001] direction, the plane wave velocity anisotropy first increases and then gradually decreases with increasing pressure, and the shear wave velocity anisotropy increases with the increase of pressure, the thermal expansion in the [100] direction is greater than that in the [001] direction. The research results are of great significance to people's understanding of the high-pressure physical properties of carbonates in the deep mantle.

10.
Front Med (Lausanne) ; 8: 688312, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34926481

RESUMEN

Purpose: Maternal lipid profile in second trimester has rarely been investigated in the risk assessment for pre-eclampsia (PE). Since early-onset PE often companied by much worse clinical outcomes, thus, we aimed to evaluate the predictive value of second-trimester maternal lipid profiling for early-onset PE. Methods: A prospective cohort study was conducted to measure the second-trimester maternal lipid profile of pregnant women from January to December 2019. The pairwise association between maternal lipid profile and PE onset or pregnancy termination time was quantified. Multiple logistic regression was preformed to define risk factors for early-onset PE, and a nomogram for early-onset PE was developed. The net benefit of our model was evaluated by calibration curve and decision curve analyses. Results: We enrolled 5,908 pregnant women and they were divided into healthy (n = 5,789), late-onset PE (n = 64), and early-onset PE (n = 55) groups. Total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-c) were elevated in patients with PE, while high-density lipoprotein cholesterol (HDL-c) was decreased in patients with PE. TC, TG, and LDL-c were negatively correlated with PE onset time or gestational week at delivery. Receiver operating characteristic curves (ROC) defined the cutoff values of TG and HDL-c, and the final regression model included five statistically significant risk predictors for early-onset PE (maternal age of ≥35 years, multipara, pre-pregnancy body mass index (BMI) ≥25 kg/m2, second trimester TG ≥ 2.59 mmol/L and second trimester HDL-c ≤ 2.03 mmol/L. The nomogram had an excellent diagnostic performance (area under the curve = 0.912, sensitivity = 92.7%, and specificity = 76%) and was further validated with good calibration and positive net benefits in a decision curve analysis. Conclusions: An abnormally increased TG concentration and a decreased HDL-c concentration might serve as predictors of early-onset PE. Whether blood lipid-lowering measures can improve severe PE prognosis require further clarification.

12.
Shanghai Kou Qiang Yi Xue ; 30(2): 140-144, 2021 Apr.
Artículo en Chino | MEDLINE | ID: mdl-34109351

RESUMEN

PURPOSE: To investigate the expression and clinical significance of B cell translocation gene 1 (BTG1) in oral squamous cell carcinoma(OSCC). METHODS: Immunohistochemical staining was used to detect the expression of BTG1 protein in 78 cases of OSCC tissues, 78 adjacent tissues, 20 normal oral mucosa tissues, and 80 cervical lymph nodes. Western blot and real-time quantitative PCR were used to detect BTG1 protein and mRNA expression levels in 78 OSCC tissues and adjacent tissues. Kaplan-Meier survival analysis, Log rank test and Cox regression analysis were performed with SPSS 21.0 software package. RESULTS: The expression level of BTG1 in OSCC and cervical positive lymph nodes was significantly lower than that in normal tissues and negative lymph nodes adjacent to the cancer, and the expression of BTG1 in poorly differentiated OSCC was significantly lower than that in highly differentiated OSCC (P<0.05); Survival analysis showed the progression-free survival (PFS) and overall survival time(OS) of BTG1 low-expression group were significantly lower than those of high-expression group (P<0.05). Cox regression analysis showed that the degree of tumor differentiation, cervical lymph node metastasis, and BTG1 expression all affected patients' prognosis. CONCLUSIONS: BTG1 is lowerly expressed in OSCC, with expression related to TNM stage and differentiation of OSCC but no relation with gender, age, and tumor location, including that BTG1 may be involved in the occurrence, development and prognosis of OSCC.


Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Carcinoma de Células Escamosas/genética , Humanos , Neoplasias de la Boca/genética , Proteínas de Neoplasias/genética , Pronóstico , Carcinoma de Células Escamosas de Cabeza y Cuello
13.
J Int Med Res ; 49(2): 300060520985338, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33557664

RESUMEN

OBJECTIVE: This study aimed to examine whether addition of cervical elastographic parameters measured by ElastoScan for the cervix (E-cervix) improves the predictive value of cervical length (CL) in induction of labor at term by dinoprostone. METHODS: We conducted a prospective, observational study between January 2020 and June 2020 in term primiparous women (n = 73) who were scheduled for labor induction by a 10-mg dinoprostone vaginal insert. The time intervals from the start of labor induction to regular uterine contractions and to vaginal delivery were calculated as the primary outcomes. We divided subjects into two groups using a threshold of 24 hours. Ultrasound measurements were compared between the two groups and the area under the curve (AUC) of the prediction model was calculated. RESULTS: Women who delivered vaginally within 24 hours had a shorter CL and softer cervix than those who delivered after 24 hours. The combination of CL and elastographic parameters increased the AUC to 0.672 compared with CL alone (AUC = 0.637). CONCLUSIONS: Measurement by E-cervix is relatively reproducible. Addition of cervical strain elastography slightly improves the predictive performance of CL in vaginal delivery within 24 hours. This technique is a promising ancillary tool for use with ultrasound.


Asunto(s)
Cuello del Útero , Diagnóstico por Imagen de Elasticidad , Cuello del Útero/diagnóstico por imagen , Parto Obstétrico , Femenino , Humanos , Trabajo de Parto Inducido , Valor Predictivo de las Pruebas , Embarazo , Estudios Prospectivos
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 191: 398-404, 2018 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-29065331

RESUMEN

Two novel N-substituted anchoring porphyrins (ZnPAtz and ZnPAim) have been devised and synthesized. Moreover, these two anchoring porphyrins were linked to the TiO2 semiconductor through carboxyl groups and then a zinc porphyrin ZnP was bound to the anchoring porphyrin using a zinc-to-ligand axial coordination approach. The different performances of these assemblies were compared with single anchoring porphyrin devices ZnPAtz and ZnPAim. The photoelectric conversion efficiency of the new supramolecular solar cells sensitized by ZnP-ZnPAx (x=tz, im) has been improved. The ZnP-ZnPAtz-based DSSCs provided the highest photovoltaic efficiency (1.86%). Fundamental studies showed that incorporation of these assemblies promote light-harvesting efficiency.

15.
J Pediatr Orthop B ; 25(5): 466-70, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27294706

RESUMEN

To compare the difference in efficacy following flexible intramedullary nailing (FIN) and external fixation (EF) for pediatric femoral shaft fractures. A systematic search was performed on PubMed, Embase, Medline, and Cochrane library for relevant studies. We included controlled trials comparing complications between FIN and EF for pediatric femoral shaft fractures published before 25 November 2014. Modified Jadad scores were utilized to assess the methodological quality of the studies included. The meta-analysis was carried out using Stata 12.0 software. Six studies involving 237 patients were included. On comparison of EF, a low incidence of overall complications [relative risk (RR)=0.30, 95% confidence interval (CI): 0.19-0.46; P<0.001] and pin-tract infection (RR=0.286, 95% CI: 0.13-0.61; P=0.001), but a high risk of soft tissue irritation (RR=1.86, 95% CI: 1.35-2.56; P<0.001) were found in patients treated with the FIN approach. No significant differences in other complications were found. On the basis of current evidence, the use of FIN leads to fewer complications than EF and may be considered as the first-line approach in the treatment of femoral shaft fractures.


Asunto(s)
Clavos Ortopédicos , Fracturas del Fémur/cirugía , Fijación Intramedular de Fracturas/efectos adversos , Fijación de Fractura/efectos adversos , Adolescente , Niño , Preescolar , Femenino , Fémur/cirugía , Humanos , Masculino , Riesgo , Programas Informáticos , Resultado del Tratamiento
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 150: 855-66, 2015 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-26116996

RESUMEN

The design and development of novel dye sensitizers are effective method to improve the performance of dye-sensitized solar cells (DSSCs) because dye sensitizers have significant influence on photo-to-current conversion efficiency. In the procedure of dye sensitizer design, it is very important to understand how to tune their electronic structures and related properties through the substitution of electronic donors, acceptors, and conjugated bridges in dye sensitizers. Here, the electronic structures and excited-state properties of organic JK dye sensitizers are calculated by using density functional theory (DFT) and time dependent DFT methods. Based upon the calculated results, we investigated the role of different electronic donors, acceptors, and π-conjugated bridges in the modification of electronic structures, absorption properties, as well as the free energy variations for electron injection and dye regeneration. In terms of the analysis of transition configurations and molecular orbitals, the effective chromophores which are favorable for electron injection in DSSCs are addressed. Meanwhile, considering the absorption spectra and free energy variation, the promising electronic donors, π-conjugated bridges, and acceptors are presented to design dye sensitizers.

17.
Bing Du Xue Bao ; 30(1): 44-50, 2014 Jan.
Artículo en Chino | MEDLINE | ID: mdl-24772897

RESUMEN

In 2013, the World Health Organization reported the first case of human infection with a new influenza A (H7N9) virus in China. This has caused damage and panic within certain areas in China. Therefore, analysis of this virus with bioinformatics technology is very necessary. Neuraminidase (NA) is one of the most important antigens of the influenza virus and an important target for anti-flu drugs. In this study, the nucleotide and protein sequences of NA gene of A/H7N9 influenza viruses were retrieved from the NCBI database, and MEGA 5.0 software was employed to construct a phylogenetic tree based on the nucleotide coding sequence; BioEdit software was used to align the nucleotide and protein sequences of NA and calculate the homologies of nucleotides and amino acids and then to analyze the important mutation sites of NA gene. The results demonstrated that the spread of influenza virus H7N9 showed certain geographical and temporal relations. The H7N9 virus isolated from China in 2013 belonged to Euroasiatic serotype, and its NA stalk region hadobvious variation, which may be one of the reasons that this virus infects human. These analyses may be very helpful for understanding the evolutionary relationship and mutation trend of A/H7N9 influenza viruses.


Asunto(s)
Evolución Molecular , Subtipo H7N9 del Virus de la Influenza A/enzimología , Subtipo H7N9 del Virus de la Influenza A/genética , Neuraminidasa/genética , Bases de Datos Genéticas , Humanos , Mutación , Neuraminidasa/química , Filogenia , Análisis de Secuencia
18.
Dalton Trans ; 43(2): 626-31, 2014 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-24132339

RESUMEN

In this work, a metal-mediated assembling strategy has been used to organize a series of new assemblies based on tetrapyridylporphyrin () on nanostructured TiO2 electrode surfaces, wherein the metal ions (, = Zn(2+), Cd(2+), Hg(2+) and Mn(2+)) bridge the pyridyl units of and (E)-4-[(pyridin-4-ylmethylene)-amino]benzoic acid (), resulting in a assembled mode. The assembled structures were characterized by transmission electron microscopy (TEM), computational calculations, energy-dispersive X-ray spectroscopy (EDX), IR, UV-vis absorption and fluorescence spectra. The performances of the assembly-sensitized solar cells were also measured under an irradiance of 100 mW cm(-2) AM 1.5G sunlight. Photoelectrochemical results reveal a relatively large photocurrent of the device. Simultaneously, a large open-circuit photovoltage and a significantly improved conversion efficiency of the device are also observed. These findings may serve as another good testing ground for the fabrication of supramolecular solar cells in future.

19.
Int J Mol Sci ; 14(10): 20171-88, 2013 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-24152435

RESUMEN

The electronic structures and excitation properties of dye sensitizers determine the photon-to-current conversion efficiency of dye sensitized solar cells (DSSCs). In order to understand the different performance of porphyrin dye sensitizers YD2 and YD2-o-C8 in DSSC, their geometries and electronic structures have been studied using density functional theory (DFT), and the electronic absorption properties have been investigated via time-dependent DFT (TDDFT) with polarizable continuum model for solvent effects. The geometrical parameters indicate that YD2 and YD2-o-C8 have similar conjugate length and charge transfer (CT) distance. According to the experimental spectra, the HSE06 functional in TDDFT is the most suitable functional for describing the Q and B absorption bands of porphyrins. The transition configurations and molecular orbital analysis suggest that the diarylamino groups are major chromophores for effective CT excitations (ECTE), and therefore act as electron donor in photon-induced electron injection in DSSCs. The analysis of excited states properties and the free energy changes for electron injection support that the better performance of YD2-o-C8 in DSSCs result from the more excited states with ECTE character and the larger absolute value of free energy change for electron injection.


Asunto(s)
Colorantes/química , Porfirinas/química , Sistema Solar/química , Absorción , Electrones
20.
Int J Mol Sci ; 14(3): 5461-81, 2013 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-23528853

RESUMEN

To understand the role of the conjugate bridge in modifying the properties of organic dye sensitizers in solar cells, the computations of the geometries and electronic structures for 10 kinds of tetrahydroquinoline dyes were performed using density functional theory (DFT), and the electronic absorption and fluorescence properties were investigated via time dependent DFT. The population analysis, molecular orbital energies, radiative lifetimes, exciton binding energies (EBE), and light harvesting efficiencies (LHE), as well as the free energy changes of electron injection ( ) and dye regeneration ( ) were also addressed. The correlation of charge populations and experimental open-circuit voltage (Voc) indicates that more charges populated in acceptor groups correspond to larger Voc. The elongating of conjugate bridge by thiophene units generates the larger oscillator strength, higher LHE, larger absolute value of , and longer relative radiative lifetime, but it induces the decreasing of EBE and . So the extending of conjugate bridge with thiopene units in organic dye is an effective way to increase the harvest of solar light, and it is also favorable for electron injection due to their larger . While the inversely correlated relationship between EBE and LHE implies that the dyes with lower EBE produce more efficient light harvesting.

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