Transient Absorption Spectroscopy (TAS) for the study of organic materials for energy conversion

Transient Absorption Spectroscopy (TAS) is a pump probe technique with the ability of directly probe the photogenerated species and their evolution with time. This technique consists in two light sources, one of them generates the photoexcited species while the other one probe those as-generated species. TAS allows to study energy transfer dynamics in a wide range of materials (organic molecules, metal complexes, inorganic materials, etc) in a wide range of media (solution, solid state, etc). Following the School spirit of this ‘Escuela de Materiales Moleculares’ this talk is going to explain the capabilities and functioning of TAS. This will include both, picosecond and microsecond TAS, with their differences in setup and applicability. This talk will focus on the application of this technique in the study of organic materials used to generate energy. Among the variety of the studied examples, there will be small molecules donors, diradicals materials. And the information that TAS is able to obtain from those.RSEQ. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Triplet-charge annihilation in a small molecule donor: acceptor blend as a major loss mechanism in organic photovoltaics

Resumen comunicación presentadaOrganic photovoltaics (OPV) are close to reaching a landmark 20% device efficiency.[1] One of the proposed reasons that OPVs have yet to attain this milestone is their propensity toward triplet formation. In this talk,[2] the small molecule donor, DRCN5T, is studied using a variety of spectroscopy techniques, and blended with both fullerene and non-fullerene acceptors. Specifically, picosecond and microsecond transient absorption and Raman spectroscopies are focused on. Despite DRCN5T's ability to achieve OPV efficiencies of over 10%,[3] it generates an unusually high population of triplets. These triplets are primarily formed in amorphous regions via back recombination from a charge transfer state. As such, triplets have a dual role in DRCN5T device efficiency suppression: they both hinder free charge carrier formation and annihilate those free charges that do form. Using microsecond transient absorption spectroscopy under oxygen conditions, this triplet-charge annihilation (TCA) is directly observed as a general phenomenon in a variety of DRCN5T: fullerene and non-fullerene blends. Since TCA is usually inferred rather than directly observed, it is demonstrated that this technique is a reliable method to establish the presence of TCA.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Dynamic Electrochemistry of Anthanthrone.

In this investigation, we present a “nanographene” based on the low-cost commercially available 4,10-dibromoanthanthrone building block, where the anthanthrone core can be viewed as a fusion of two anthracene moieties with lateral functionalization. The chemical and physical properties of this molecule stand in sharp contrast with the present anthracene subunit. We have studied the dynamic electrochemistry from two derivates of anthanthrone where the research depends on the radical of peripheral phenyl groups. In this case, we compared the changes that produce a donor group and acceptor group respectively. In both cases, the neutral molecule has a butterfly shape due to the steric congestion between the protons at the peri position of the quinoidal anthanthrone core, which possess a nonplanar folded geometry, and the protons from the peripheral phenyl groups. However, when two electrons are subtracted, exist a core aromatization and planarization, this provides a stable flat shape. We show the existence of two conformational states through cyclic voltammetry, electrochemistry and variable temperature chemistry oxidation. We demonstrate the fast or slow equilibrium between both geometries depending on the radical of peripheral phenyl groups (donor or acceptor).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Clinical course of patients with severe COVID-19 pneumonia treated with remdesivir: A real-life study.

BackgroundThere is currently much uncertainty regarding the most optimal treatment for COVID-19. This study analyze the change in the clinical condition of patients hospitalized for severe COVID-19 pneumonia and treated with remdesivir in a real-life setting, based on the WHO Ordinal Scale. Clinical complications, treatment safety, and impact of other associated drugs were also analyzed.MethodsWe conducted an observational, retrospective study including patients treated with remdesivir. The need for admission to the ICU, the length of ICU and hospital stay, and the need for ventilatory support were analyzed. The laboratory parameters, drugs administered concomitantly, and difference in the length of hospital stay according to the concomitant treatment received were also evaluated. A univariate and multivariate Cox regression analysis was performed to analyze associated factors.ResultsA total of 92 patients were included. The mean length of hospital stay was 15 days, and 90% of the patients had been discharged from the hospital 28 days after starting treatment with remdesivir. The likelihood of hospital discharge among patients not presenting with hypertension as a comorbidity was significantly higher than that of those with this condition (HR = 3.19, P = 0.008). Nineteen patients had to be admitted to the ICU (mean of 18 days). Approximately 11% required invasive mechanical ventilation (mean of 22 days). Almost 37% of the patients received high-flow oxygen therapy and 14% non-invasive mechanical ventilation. Four deaths were recorded within the first week. Main adverse events were increases in transaminase and creatinine levels. Nosocomial infections were more frequent when remdesivir was combined with immunosuppressive drugs.ConclusionsPatients with severe COVID-19 pneumonia and treated with remdesivir require relatively prolonged hospital stays, many with a need for ventilatory support and, in a considerable proportion of cases, admission to the ICU. However, the observed survival rate is high, and the drug is well tolerated

Hepatitis B and C viral infections in patients with hepatocellular carcinoma

The prevalence of hepatitis B and C virus infections was studied in 70 patients diagnosed as having hepatocellular carcinoma. In addition to viral serological markers, serum hepatitis B virus DNA and hepatitis C virus RNA were determined with a nested polymerase chain reaction assay. Twelve patients (17%) were HBsAg positive, 26 (37%) had antibodies to HBs, HBc or both and 32 (46%) were negative for all hepatitis B virus serological markers. Prevalence of the antibody to hepatitis C virus was 63% (44 patients). Hepatitis B virus DNA was detected in 24 of the 66 tested patients (36%). Twelve of these hepatitis B virus DNA-positive patients were HBsAg negative (seven were positive for antibody to HBs, antibody to HBc or both and five were negative for all hepatitis B virus serological markers). Hepatitis C virus RNA was found in 42 of 68 patients (62%). A high correlation (95%) existed between hepatitis C virus RNA and hepatitis C virus antibodies. Nevertheless, two patients without antibody to hepatitis C virus had serum hepatitis C virus RNA sequences. Coinfection by the two viruses was detected in nine subjects (14%), but no clinical differences were found between these and the rest of the patients. We conclude that nearly 90% (62 of the 70 patients studied) of cases of hepatocellular carcinoma in our geographical area are related to hepatitis virus infections (detected by serological or molecular studies). Hepatitis C is more prevalent than hepatitis B virus in patients with hepatocellular carcinoma, and the infection is still active when the tumor is diagnosed

CCL20 Is Increased in Hypercholesterolemic Subjects and Is Upregulated By LDL in Vascular Smooth Muscle Cells

International audienceObjective-Our aim was to analyze the regulation of CC Chemokine ligand 20 (CCL20) by LDL in human vascular smooth muscle cells (VSMC). Methods and Results-In asymptomatic subjects, circulating CCL20 levels were higher in patients with hypercholesterolemia (18.5Ϯ3.2 versus 9.1Ϯ1.3 pg/mL; PϽ0.01). LDL induced the expression of CCL20 in VSMC in a dose-and time-dependent manner. Increased levels of CCL20 secreted by LDL-treated VSMC significantly induced human lymphocyte migration, an effect reduced by CCL20 silencing. The upregulation of CCL20 by LDL was dependent on the activation of kinase signaling pathways and NF-B. By site-directed mutagenesis, electrophoretic mobility shift assay, and chromatin immunoprecipitation, we identified a NF-B site (Ϫ80/Ϫ71) in CCL20 promoter critical for LDL responsiveness. Lysophosphatidic acid mimicked the upregulation of CCL20 induced by LDL, and minimal oxidation of LDL increased the ability of LDL to induce CCL20 through a mechanism that involves lysophosphatidic acid receptors. CCL20 was overexpressed in atherosclerotic lesions from coronary artery patients, colocalizing with VSMC. CCL20 was detected in conditioned media from healthy human aorta and its levels were significantly higher in secretomes from carotid endarterectomy specimens. Conclusion-This study identifies CCL20 in atherosclerotic lesions and recognizes this chemokine as a mediator highly sensitive to the inflammatory response elicited by LDL

Does chronic kidney disease facilitate malignant myocardial fibrosis in heart failure with preserved ejection fraction of hypertensive origin?

In hypertensive patients with heart failure (HF) a serum biomarker combination of high carboxy-terminal propeptide of procollagen type-I (PICP) and low carboxy-terminal telopeptide of collagen type-I to matrix metalloproteinase-1 (CITP:MMP-1) ratio identifies a histomolecular phenotype of malignant myocardial fibrosis (mMF) associated with severe diastolic dysfunction (DD) and poor outcomes. As chronic kidney disease (CKD) facilitates MF and DD, we investigated the influence of CKD on the mMF biomarker combination in HF patients with preserved ejection fraction (HFpEF). Hypertensives (n = 365), 232 non-HF and 133 HFpEF, were studied, and 35% non-HF and 46% HFpEF patients had CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2 or urine albumin-to-creatinine ratio ≥ 30 mg/g). Specific immunoassays were performed to determine biomarkers. Medians were used to establish the high PICP and low CITP:MMP-1 combination. A comparison with non-HF showed that the biomarker combination presence was increased in HFpEF patients, being associated with CKD in all patients. CKD influenced the association of the biomarker combination and HFpEF (p for interaction ≤ 0.019). The E:e’ ratio was associated with the biomarker combination in CKD patients. Among CKD patients with HFpEF, those with the biomarker combination exhibited higher (p = 0.016) E:e’ ratio than those without the pattern. These findings suggest that CKD facilitates the development of biomarker-assessed mMF and DD in hypertensive HFpEF patients

CCL20 is increased in hypercholesterolemic subjects and is upregulated by LDL in vascular smooth muscle cells: role of NF-κB

OBJECTIVE: Our aim was to analyze the regulation of CC Chemokine ligand 20 (CCL20) by LDL in human vascular smooth muscle cells (VSMC). METHODS AND RESULTS: In asymptomatic subjects, circulating CCL20 levels were higher in patients with hypercholesterolemia (18.5±3.2 versus 9.1±1.3 pg/mL; P<0.01). LDL induced the expression of CCL20 in VSMC in a dose- and time-dependent manner. Increased levels of CCL20 secreted by LDL-treated VSMC significantly induced human lymphocyte migration, an effect reduced by CCL20 silencing. The upregulation of CCL20 by LDL was dependent on the activation of kinase signaling pathways and NF-κB. By site-directed mutagenesis, electrophoretic mobility shift assay, and chromatin immunoprecipitation, we identified a NF-κB site (-80/-71) in CCL20 promoter critical for LDL responsiveness. Lysophosphatidic acid mimicked the upregulation of CCL20 induced by LDL, and minimal oxidation of LDL increased the ability of LDL to induce CCL20 through a mechanism that involves lysophosphatidic acid receptors. CCL20 was overexpressed in atherosclerotic lesions from coronary artery patients, colocalizing with VSMC. CCL20 was detected in conditioned media from healthy human aorta and its levels were significantly higher in secretomes from carotid endarterectomy specimens. CONCLUSION: This study identifies CCL20 in atherosclerotic lesions and recognizes this chemokine as a mediator highly sensitive to the inflammatory response elicited by LDL

V-Shaped Tröger Oligothiophenes Boost Triplet Formation by CT Mediation and Symmetry Breaking

A new family of molecules obtained by coupling Tröger’s base unit with dicyanovinylene-terminated oligothiophenes of different lengths has been synthesized and characterized by steady-state stationary and transient time-resolved spectroscopies. Quantum chemical calculations allow us to interpret and recognize the properties of the stationary excited states as well as the time-dependent mechanisms of singlet-to-triplet coupling. The presence of the diazocine unit in Tröger’s base derivatives is key to efficiently producing singlet-to-triplet intersystem crossing mediated by the role of the nitrogen atoms and of the almost orthogonal disposition of the two thiophene arms. Spin–orbit coupling-mediated interstate intersystem crossing (ISC) is activated by a symmetry-breaking process in the first singlet excited state with partial charge transfer character. This mechanism is a characteristic of these molecular triads since the independent dicyanovinylene-oligothiophene branches do not display appreciable ISC. These results show how Tröger’s base coupling of organic chromophores can be used to improve the ISC efficiency and tune their photophysics

Does chronic kidney disease facilitate malignant myocardial fibrosis in heart failure with preserved ejection fraction of hypertensive origin?

In hypertensive patients with heart failure (HF) a serum biomarker combination of high carboxy-terminal propeptide of procollagen type-I (PICP) and low carboxy-terminal telopeptide of collagen type-I to matrix metalloproteinase-1 (CITP:MMP-1) ratio identifies a histomolecular phenotype of malignant myocardial fibrosis (mMF) associated with severe diastolic dysfunction (DD) and poor outcomes. As chronic kidney disease (CKD) facilitates MF and DD, we investigated the influence of CKD on the mMF biomarker combination in HF patients with preserved ejection fraction (HFpEF). Hypertensives (n = 365), 232 non-HF and 133 HFpEF, were studied, and 35% non-HF and 46% HFpEF patients had CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2 or urine albumin-to-creatinine ratio ≥ 30 mg/g). Specific immunoassays were performed to determine biomarkers. Medians were used to establish the high PICP and low CITP:MMP-1 combination. A comparison with non-HF showed that the biomarker combination presence was increased in HFpEF patients, being associated with CKD in all patients. CKD influenced the association of the biomarker combination and HFpEF (p for interaction ≤ 0.019). The E:e’ ratio was associated with the biomarker combination in CKD patients. Among CKD patients with HFpEF, those with the biomarker combination exhibited higher (p = 0.016) E:e’ ratio than those without the pattern. These findings suggest that CKD facilitates the development of biomarker-assessed mMF and DD in hypertensive HFpEF patients