The dual nature of metal halide perovskites.

Metal halide perovskites have brought about a disruptive shift in the field of third-generation photovoltaics. Their potential as remarkably efficient solar cell absorbers was first demonstrated in the beginning of the 2010s. However, right from their inception, persistent challenges have impeded the smooth adoption of this technology in the industry. These challenges encompass issues such as the lack of reproducibility in fabrication, limited mid- and long-term stability, and concerns over toxicity. Despite achieving record efficiencies that have outperformed even well-established technologies, such as polycrystalline silicon, these hurdles have hindered the seamless transition of this technology into industrial applications. In this Perspective, we discuss which of these challenges are rooted in the unique dual nature of metal halide perovskites, which simultaneously function as electronic and ionic semiconductors. This duality results in the intermingling of processes occurring at vastly different timescales, still complicating both their comprehensive investigation and the development of robust and dependable devices. Our discussion here undertakes a critical analysis of the field, addressing the current status of knowledge for devices based on halide perovskites in view of electronic and ionic conduction, the underlying models, and the challenges encountered when these devices are optoelectronically characterized. We place a distinct emphasis on the positive contributions that this area of research has not only made to the advancement of photovoltaics but also to the broader progress of solid-state physics and photoelectrochemistry.

Polimorfismos genéticos asociados a la respuesta del carcinoma de cabeza y cuello al cetuximab / Genetic polymorphisms associated with the response of head and neck carcinoma to cetuximab

Objetivo: Exponer los principales polimorfismos genéticos que han sido asociados a la respuesta del carcinoma de cabeza y cuello al cetuximab. Método: Se realizó una revisión no exhaustiva de artículos publicados en el período de enero de 2000 a diciembre de 2022, para ello se emplearon las bases de datos Medline (vía Pubmed) y Science Direct. En la evaluación de la calidad metodológica de los artículos incluidos se utilizó la guía para los estudios de asociación genética (Q-Genie). Resultados: Se identificaron un total de 206 artículos, de los cuales 12 cumplieron con los criterios para el análisis final. Se reportaron varios polimorfismos, tales como: EGFR-R521K (AA/GA), FcγRIIIa (158VV) y FcγRIIa (131HH), KRASLCS6 (TG/GG), AKT2:rs8100018, PTEN: rs12569998 en sus variantes mutadas, HIF-1α (CT/TT) y XRCC5 (GG/AA) que se asociaron con las variables de supervivencia, riesgo de progresión, tiempos hasta la progresión de la enfermedad, así como toxicidad cutánea. Conclusiones: Varios polimorfismos pueden asociarse con la respuesta del carcinoma de cabeza y cuello al tratamiento con cetuximab, siendo EGFR-R521K y FcγR IIIa-V158F los más estudiados. La enorme incertidumbre de los resultados alcanzados no permite alcanzar conclusiones firmes sobre la influencia de los polimorfismos genéticos en la respuesta al cetuximab; sin embargo, pueden convertirse en biomarcadores farmacogenéticos en la práctica clínica como una valiosa herramienta en la medicina personalizada, para predecir la respuesta medicamentosa. Para ello se requiere la realización de ensayos controlados con estratos por genotipo, con asignación aleatoria del tratamiento y el análisis de otras variables con valor pronóstico conocido.(AU)

Objective: To present the main genetic polymorphisms that have been associated with the response of head and neck carcinoma to cetuximab. Method: A non-exhaustive review of articles published in the period from January 2000 to December 2022 was carried out, for this purpose the Medline (via Pubmed) and Science Direct databases were used. The guide for genetic association studies (Q-Genie) was used to evaluate the methodological quality of the included articles. Results: A total of 206 articles were identified, of which 12 met the criteria for the final analysis. Several polymorphisms were reported, such as: EGFR-R521K (AA/GA), FcγRIIIa (158VV) and FcγRIIa (131HH), KRAS-LCS6 (TG/GG), AKT2:rs8100018, PTEN: rs12569998 in its mutated variants, HIF- 1α (CT/TT) and XRCC5 (GG/AA) that were associated with survival variables, risk of progression, times to disease progression, as well as skin toxicity. Conclusions: Several polymorphisms can be associated with the response of head and neck carcinoma to treatment with cetuximab, being EGFR-R521K and FcγR IIIa-V158F the most studied. The enormous uncertainty of the results obtained does not allow firm conclusions to be reached about the influence of genetic polymorphisms on the response to cetuximab; however, they can become pharmacogenetic biomarkers in clinical practice as a valuable tool in personalized medicine, to predict drug response. This requires carrying out controlled trials with strata by genotype, with random assignment of treatment and the analysis of other variables with known prognostic value.(AU)

Influence of Redox Couple on the Performance of ZnO Dye Solar Cells and Minimodules with Benzothiadiazole-Based Photosensitizers.

ZnO-based dye-sensitized solar cells exhibit lower efficiencies than TiO2-based systems despite advantageous charge transport dynamics and versatility in terms of synthesis methods, which can be primarily ascribed to compatibility issues of ZnO with the dyes and the redox couples originally optimized for TiO2. We evaluate the performance of solar cells based on ZnO nanomaterial prepared by microwave-assisted solvothermal synthesis, using three fully organic benzothiadiazole-based dyes YKP-88, YKP-137, and MG-207, and alternative electrolyte solutions with the I-/I3 -, Co(bpy)3 2+/3+, and Cu(dmp)2 1+/2+ redox couples. The best cell performance is achieved for the dye-redox couple combination YKP-88 and Co(bpy)3 2+/3+, reaching an average efficiency of 4.7% and 5.0% for the best cell, compared to 3.7% and 3.9% for the I-/I3 - couple with the same dye. Electrical impedance spectroscopy highlights the influence of dye and redox couple chemistry on the balance of recombination and regeneration kinetics. Combined with the effects of the interaction of the redox couple with the ZnO surface, these aspects are shown to determine the solar cell performance. Minimodules based on the best systems in both parallel and series configurations reach 1.5% efficiency for an area of 23.8 cm2.

Photochromic spiro-indoline naphthoxazines and naphthopyrans in dye-sensitized solar cells.

Photochromic dyes possess unique properties that can be exploited in different domains, including optics, biomedicine and optoelectronics. Herein, we explore the potential of photochromic spiro-indoline naphthoxazine (SINO) and naphthopyran (NIPS) for application in photovoltaics. We designed and synthesized four new photosensitizers with a donor-pi-acceptor structure embedding SINO and NIPS units as photochromic cores. Their optical, photochromic and acidochromic properties were thoroughly studied to establish structure-properties relationships. Then, after unravelling the possible forms adopted depending on the stimuli, their photovoltaic properties were evaluated in DSSCs. Although the photochromic behavior is not always preserved, we elucidate the interplay between photochromic, acidochromic and photovoltaic properties and we demonstrate that these dyes can act as photosensitizers in DSSCs. We report a maximum power conversion efficiency of 2.7% with a NIPS-based dye, a tenfold improvement in comparison to previous works on similar class of compounds. This work opens new perspectives of developments for SINO and NIPS in optical and photovoltaic devices, and it provides novel research directions to design photochromic materials with improved characteristics.

Photochromic naphthopyran dyes incorporating a benzene, thiophene or furan spacer: effect on photochromic, optoelectronic and photovoltaic properties in dye-sensitized solar cells.

We recently demonstrated that diaryl-naphthopyran photochromic dyes are efficient for sensitization of TiO2 mesoporous electrodes, thus allowing the fabrication of photo-chromo-voltaic cells that can self-adapt their absorption of light and their generation of electricity with the light intensity. Herein we report the synthesis, the characterisation of two novel photochromic dyes based on diaryl-naphthopyran core i.e NPI-ThPh and NPI-FuPh for use in Dye Sensitized Solar Cells (DSSCs). Compared to our reference dye NPI, the molecules only vary by the nature of the spacer, a thiophene or a furan, connecting the photochromic unit and the phenyl-cyano-acrylic acid moiety used as the anchoring function. We found that swapping a phenyl for a thiophene or a furan leads to an improvement of the absorption properties of the molecules both in solution and after grafting on TiO2 electrodes, however their photochromic process becomes not fully reversible. Despite better absorption in the visible range, the new dyes show poorer photochromic and photovoltaic properties in devices compared to NPI. Thanks to UV-Vis spectroscopy, DFT calculation, electrical characterization of the cells, and impedance spectroscopy, we unravel the factors limiting their performances. Our study contributes to better understand the connection between photochromic and photovoltaic properties, which is key to develop better performing molecules of this class.

Photophysical and Photoelectrochemical Properties of CsPbBr3 Films Grown by Electrochemically Assisted Deposition.

Perovskite have had a great impact on the solid-state physics world in the last decade not only achieving great success in photovoltaics but, more recently, also in the implementation of other optoelectronic devices. One of the main obstacles for the adoption of Pb-based perovskite technologies are the high amounts of Pb needed in the conventional preparation methods. Here we present for the first time a detailed analysis of the photophysical and photoelectrochemical properties of CsPbBr3 films directly grown on fluorine-doped tin oxide (FTO) coated glass through a novel technique based in the electrodeposition of PbO2 as CsPbBr3 precursor. This technique allows to save up to 90 % of the Pb used compared to traditional methods and can be scalable compared with the commonly used spin-coating process. The low temperature analysis of their photoluminescence spectra, performed in both steady state and time dependence, revealed a strong interaction between electrons and longitudinal optical (LO) phonons dominant at high temperatures. On the other hand, the electrochemical and photoelectrochemical analysis proves that CsPbBr3 prepared using this new method has state-of-the-art features, showing a p-type behavior under depletion regime. This is also confirmed by photoelectrochemical measurements using p-benzoquinone as target molecule. These results prove that the proposed method can be used to produce excellent CsPbBr3 films, saving much of the lead waste.

Understanding equivalent circuits in perovskite solar cells. Insights from drift-diffusion simulation.

Perovskite solar cells (PSCs) have reached impressively high efficiencies in a short period of time; however, the optoelectronic properties of halide perovskites are surprisingly complex owing to the coupled ionic-electronic charge carrier dynamics. Electrical impedance spectroscopy (EIS) is a widely used characterization tool to elucidate the mechanisms and kinetics governing the performance of PSCs, as well as of many other semiconductor devices. In general, equivalent circuits are used to evaluate EIS results. Oftentimes these are justified via empirical constructions and the real physical meaning of the elements remains disputed. In this perspective, we use drift-diffusion numerical simulations of typical thin-film, planar PSCs to generate impedance spectra avoiding intrinsic experimental difficulties such as instability and low reproducibility. The ionic and electronic properties of the device, such as ion vacancy density, diffusion coefficients, recombination mechanism, etc., can be changed individually in the simulations, so their effects can be directly observed. We evaluate the resulting EIS spectra by comparing two commonly used equivalent circuits with series and parallel connections respectively, which result in two signals with significantly different time constants. Both circuits can fit the EIS spectra and by extracting the values of the elements of one of the circuits, the values of the elements of the other circuit can be unequivocally obtained. Consequently, both can be used to analyse the EIS of a PSC. However, the physical meaning of each element in each circuit could differ. EIS can produce a broad range of physical information. We analyse the physical interpretation of the elements of each circuit and how to correlate the elements of one circuit with the elements of the other in order to have a direct picture of the physical processes occurring in the device.

Transferable Classical Force Field for Pure and Mixed Metal Halide Perovskites Parameterized from First-Principles.

Many key features in photovoltaic perovskites occur in relatively long time scales and involve mixed compositions. This requires realistic but also numerically simple models. In this work we present a transferable classical force field to describe the mixed hybrid perovskite MAxFA1-xPb(BryI1-y)3 for variable composition (∀x, y ∈ [0, 1]). The model includes Lennard-Jones and Buckingham potentials to describe the interactions between the atoms of the inorganic lattice and the organic molecule, and the AMBER model to describe intramolecular atomic interactions. Most of the parameters of the force field have been obtained by means of a genetic algorithm previously developed to parametrize the CsPb(BrxI1-x)3 perovskite (Balestra et al. J. Mater. Chem. A. 2020, DOI: 10.1039/d0ta03200j). The algorithm finds the best parameter set that simultaneously fits the DFT energies obtained for several crystalline structures with moderate degrees of distortion with respect to the equilibrium configuration. The resulting model reproduces correctly the XRD patterns, the expansion of the lattice upon I/Br substitution, and the thermal expansion coefficients. We use the model to run classical molecular dynamics simulations with up to 8600 atoms and simulation times of up to 40 ns. From the simulations we have extracted the ion diffusion coefficient of the pure and mixed perovskites, presenting for the first time these values obtained by a fully dynamical method using a transferable model fitted to first-principles calculations. The values here reported can be considered as the theoretical upper limit, that is, without grain boundaries or other defects, for ion migration dynamics induced by halide vacancies in photovoltaic perovskite devices under operational conditions.

Challenges of modeling nanostructured materials for photocatalytic water splitting.

Understanding the water splitting mechanism in photocatalysis is a rewarding goal as it will allow producing clean fuel for a sustainable life in the future. However, identifying the photocatalytic mechanisms by modeling photoactive nanoparticles requires sophisticated computational techniques based on multiscale modeling. In this review, we will survey the strengths and drawbacks of currently available theoretical methods at different length and accuracy scales. Understanding the surface-active site through Density Functional Theory (DFT) using new, more accurate exchange-correlation functionals plays a key role for surface engineering. Larger scale dynamics of the catalyst/electrolyte interface can be treated with Molecular Dynamics albeit there is a need for more generalizations of force fields. Monte Carlo and Continuum Modeling techniques are so far not the prominent path for modeling water splitting but interest is growing due to the lower computational cost and the feasibility to compare the modeling outcome directly to experimental data. The future challenges in modeling complex nano-photocatalysts involve combining different methods in a hierarchical way so that resources are spent wisely at each length scale, as well as accounting for excited states chemistry that is important for photocatalysis, a path that will bring devices closer to the theoretical limit of photocatalytic efficiency.

Highly Anisotropic Organometal Halide Perovskite Nanowalls Grown by Glancing-Angle Deposition.

Polarizers are ubiquitous components in current optoelectronic devices as displays or photographic cameras. Yet, control over light polarization is an unsolved challenge, since the main drawback of the existing display technologies is the significant optical losses. In such a context, organometal halide perovskites (OMHP) can play a decisive role given their flexible synthesis with tunable optical properties such as bandgap and photoluminescence, and excellent light emission with a low non-radiative recombination rate. Therefore, along with their outstanding electrical properties have elevated hybrid perovskites as the material of choice in photovoltaics and optoelectronics. Among the different OMHP nanostructures, nanowires and nanorods have lately arisen as key players in the control of light polarization for lighting or detector applications. Herein, the fabrication of highly aligned and anisotropic methylammonium lead iodide perovskite nanowalls by glancing-angle deposition, which is compatible with most substrates, is presented. Their high alignment degree provides the samples with anisotropic optical properties such as light absorption and photoluminescence. Furthermore, their implementation in photovoltaic devices provides them with a polarization-sensitive response. This facile vacuum-based approach embodies a milestone in the development of last-generation polarization-sensitive perovskite-based optoelectronic devices such as lighting appliances or self-powered photodetectors.

Endoscopic versus open surgery in patients with malignant sinonasal tumours and brain invasion. A case series study.

OBJECTIVES: To determine the safety, effectiveness and perioperative costs of endonasal endoscopic approach in brain invasive malignant sinonsal tumours patients. MATERIALS AND METHODS: This was a case series bidirectional study; that included 30 brain invasive malignant sinonsal tumours patients treated by endonasal endoscopic approach (2015-2017) and 53 by open surgery (2010-2015). Propensity score matching was used to compensate the prognostic factors; in a sample of 50 patients (25 per group). Primary response variables was local control and 3-years overall survival. Perioperative cost variables were analyzed. RESULTS: A number of 50 patients were included after matching (25 in each therapeutic group). The age average was 55 years and male proportion was 62%. Squamous cell carcinoma and grade II lesions were the most represented in the sample. Endonasal endoscopic approach reduced surgical time in 1 h 20 min, transfusion needs in 5.5 fold and hospitalization in 19 days; in comparison with open technique. Oncologic control based on surgical free margins, local control, overall survival and progression free survival after three years was higher when the resection was performed endoscopically. Functional status was enhanced and complications diminished by using endoscopic approach. Saving was estimated in $7 355.18 per patient. CONCLUSIONS: Endonasal endoscopic approach represents a safe, effective and economic procedure in selected patients with malignant sinonasal tumors and brain invasion.

Characterization of Photochromic Dye Solar Cells Using Small-Signal Perturbation Techniques.

Photochromic dye-sensitized solar cells (DSSCs) are novel semi-transparent photovoltaic devices that self-adjust their optical properties to the irradiation conditions, a feature that makes them especially suitable for building integrated photovoltaics. These novel solar cells have already achieved efficiencies above 4%, and there are multiple pathways to improve the performance. In this work, we conduct a full characterization of DSSCs with the photochromic dye NPI, combining electrical impedance spectroscopy (EIS) and intensity-modulated photocurrent spectroscopy (IMPS). We argue that the inherent properties of the photochromic dye, which result in a modification of the functioning of the solar cell by the optical excitation that also acts as a probe, pose unique challenges to the interpretation of the results using conventional models. Absorption of light in the visible range significantly increases when the NPI dye is in the activated state; however, the recombination rate also increases, thus limiting the efficiency. We identify and quantify the mechanism of enhanced recombination when the photochromic dye is activated using a combination of EIS and IMPS. From the comparison to a state-of-the-art reference dye (RK1), we were able to detect a new feature in the IMPS spectrum that is associated with the optical activation of the photochromic dye, providing a useful tool for assessing the electronic behavior of the device under different conditions of light excitation. This study provides guidelines to adequate characterization protocols of photochromic solar cells and essential insights on the interfacial electronic processes.

Illumination Intensity Dependence of the Recombination Mechanism in Mixed Perovskite Solar Cells.

Recombination mechanisms in solar cells are frequently assessed through the determination of ideality factors. In this work we report an abrupt change of the value of the "apparent" ideality factor (nAP ) in high-efficiency FA0.71 MA0.29 PbI2.9 Br0.1 based mesoscopic perovskite solar cells as a function of light intensity. This change is manifested as a transition from a regime characterized by nAP ∼1.8-2.5 at low light intensities (<10 mWcm-2 ) to one characterized by nAP ∼1. This transition is equally observed in the recombination resistance extracted from open-circuit impedance measurements. We use drift-diffusion simulations with explicit consideration of ion migration to determine the origin of this transition. We find that a change ofrecombination mechanism concurrent with a modification of the concentration of ionic vacancies is the most likely explanation of the observed behaviour. In the drift-diffusion simulations we show that the apparent ideality factor is in fact affected by the ion vacancy concentration so it is not the optimal parameter to assess the dominant recombination mechanism. We argue that a procedure based on a recently derived "electronic" ideality factor obtained from the high frequency feature of the impedance spectrum is better suited to determine the recombination route that dictates the photovoltage.

Endoscopic versus open surgery in patients with malignant sinonasal tumors and brain invasion. A case series study. / Cirugía endoscópica vs. cirugía abierta en pacientes con neoplasias nasosinusales malignas con invasión cerebral. Estudio de serie de casos.

OBJECTIVES: To determine the safety, effectiveness and perioperative costs of endonasal endoscopic approach in brain invasive malignant sinonsal tumors patients. MATERIALS AND METHODS: This was a case series bidirectional study; that included 30 brain invasive malignant sinonsal tumors patients treated by endonasal endoscopic approach (2015-2017) and 53 by open surgery (2010-2015). Propensity score matching was used to compensate the prognostic factors; in a sample of 50 patients (25 per group). Primary response variables was local control and 3-years overall survival. Perioperative cost variables were analyzed. RESULTS: A number of 50 patients were included after matching (25 in each therapeutic group). The age average was 55 years and male proportion was 62%. Squamous cell carcinoma and grade II lesions were the most represented in the sample. Endonasal endoscopic approach reduced surgical time in 1 hour 20 minutes, transfusion needs in 5.5 fold and hospitalization in 19 days; in comparison with open technique. Oncologic control based on surgical free margins, local control, overall survival and progression free survival after three years was higher when the resection was performed endoscopically. Functional status was enhanced and complications diminished by using endoscopic approach. Saving was estimated in $7 355.18 per patient. CONCLUSIONS: Endonasal endoscopic approach represents a safe, effective and economic procedure in selected patients with malignant sinonasal tumors and brain invasion.

Gene network and biological pathways associated with susceptibility to differentiated thyroid carcinoma.

Variants identified in earlier genome-wide association studies (GWAS) on differentiated thyroid carcinoma (DTC) explain about 10% of the overall estimated genetic contribution and could not provide complete insights into biological mechanisms involved in DTC susceptibility. Integrating systems biology information from model organisms, genome-wide expression data from tumor and matched normal tissue and GWAS data could help identifying DTC-associated genes, and pathways or functional networks in which they are involved. We performed data mining of GWAS data of the EPITHYR consortium (1551 cases and 1957 controls) using various pathways and protein-protein interaction (PPI) annotation databases and gene expression data from The Cancer Genome Atlas. We identified eight DTC-associated genes at known loci 2q35 (DIRC3), 8p12 (NRG1), 9q22 (FOXE1, TRMO, HEMGN, ANP32B, NANS) and 14q13 (MBIP). Using the EW_dmGWAS approach we found that gene networks related to glycogenolysis, glycogen metabolism, insulin metabolism and signal transduction pathways associated with muscle contraction were overrepresented with association signals (false discovery rate adjusted p-value < 0.05). Additionally, suggestive association of 21 KEGG and 75 REACTOME pathways with DTC indicate a link between DTC susceptibility and functions related to metabolism of cholesterol, amino sugar and nucleotide sugar metabolism, steroid biosynthesis, and downregulation of ERBB2 signaling pathways. Together, our results provide novel insights into biological mechanisms contributing to DTC risk.

Multiethnic genome-wide association study of differentiated thyroid cancer in the EPITHYR consortium.

Incidence of differentiated thyroid carcinoma (DTC) varies considerably between ethnic groups, with particularly high incidence rates in Pacific Islanders. DTC is one of the cancers with the highest familial risk suggesting a major role of genetic risk factors, but only few susceptibility loci were identified so far. In order to assess the contribution of known DTC susceptibility loci and to identify new ones, we conducted a multiethnic genome-wide association study (GWAS) in individuals of European ancestry and of Oceanian ancestry from Pacific Islands. Our study included 1554 cases/1973 controls of European ancestry and 301 cases/348 controls of Oceanian ancestry from seven population-based case-control studies participating to the EPITHYR consortium. All participants were genotyped using the OncoArray-500K Beadchip (Illumina). We confirmed the association with the known DTC susceptibility loci at 2q35, 8p12, 9q22.33 and 14q13.3 in the European ancestry population and suggested two novel signals at 1p31.3 and 16q23.2, which were associated with thyroid-stimulating hormone levels in previous GWAS. We additionally replicated an association with 5p15.33 reported previously in Chinese and European populations. Except at 1p31.3, all associations were in the same direction in the population of Oceanian ancestry. We also observed that the frequencies of risk alleles at 2q35, 5p15.33 and 16q23.2 were significantly higher in Oceanians than in Europeans. However, additional GWAS and epidemiological studies in Oceanian populations are needed to fully understand the highest incidence observed in these populations.

Satisfacción con los resultados estéticos de la reconstrucción mamaria posmastectomía, en el Instituto Nacional de Oncología y Radiobiología (INOR) de Cuba, mediante el cuestionario BREAST-Q / Satisfaction with the aesthetic results of post-mastectomy breast reconstruction at the Cuban Institute of Oncology (INOR) by using the BREAST-Q questionnaire

INTRODUCCIÓN: El tratamiento quirúrgico del cáncer de mama deja secuelas deformantes, por tanto, la reconstrucción mamaria es considerada parte integral del tratamiento. Evaluar la satisfacción de las pacientes sobre los resultados estéticos de la reconstrucción orienta hacia la efectividad de las técnicas quirúrgicas empleadas. OBJETIVOS: Evaluar la satisfacción con los resultados estéticos de las pacientes reconstruidas posmastectomía, y comparar estos resultados con la simetría frontal mamaria posquirúrgica. MÉTODOS: Se realizó un estudio de serie de casos en 40 pacientes reconstruidas posmastectomía en el periodo 2013-2018 en el Instituto Nacional de Oncología y Radiobiología (INOR) de Cuba. Se evaluó la satisfacción sobre sus resultados estéticos mediante el cuestionario BREAST-Q modificado. El test no paramétrico de Kruskal-Wallis se usó para determinar diferencias de los niveles de satisfacción entre grupos de covariables. Los resultados se correlacionaron con la medida de la simetría frontal global posquirúrgica mediante la correlación de Spearman. RESULTADOS: Se obtuvieron altos niveles satisfacción de las pacientes reconstruidas en las escalas evaluadas, con medianas por encima de 95 puntos. Pacientes entre 35 y 54 años alcanzaron puntuaciones significativamente más altas (p < 0,05). La satisfacción con la apariencia de las mamas correlacionó positiva y significativamente con la simetría frontal posquirúrgica. CONCLUSIONES: Los altos niveles de satisfacción alcanzados sugieren una alta efectividad de las técnicas quirúrgicas reconstructivas empleadas, especialmente con la técnica de dorsal ancho más implante; la correlación positiva entre la satisfacción con la apariencia de las mamas y la simetría global posquirúrgica verifica esta afirmación

INTRODUCTION: The surgical treatment of breast cancer leaves deforming sequelae; therefore, breast reconstruction is considered an integral part of the treatment. Evaluating patient satisfaction with the aesthetic results of reconstruction is one way to assess the effectiveness of the surgical techniques used. OBJECTIVES: To evaluate satisfaction with aesthetic results in patients reconstructed after mastectomy and to compare these results with frontal breast symmetry after surgery. METHODS: A case series study was conducted in 40 reconstructed post-mastectomy patients from 2013-2018 at INOR. Satisfaction with aesthetic results was evaluated using the modified Breast Q survey. Differences in satisfaction levels between groups of covariates were determined by the non-parametric Kruskal-Wallis test. The results were correlated with measurement of post-surgical global frontal symmetry using Spearman's correlation. RESULTS: High satisfaction levels were obtained in reconstructed patients in the evaluated scales, with medians above 95 points. Scores were significantly higher in patients aged between 35 and 54 years (p < 0.05). Satisfaction with breast appearance correlated positively and significantly with post-surgical frontal symmetry. CONCLUSIONS: The high satisfaction levels achieved suggest a high effectiveness of the reconstructive surgical techniques used, especially with latissimus dorsi plus implant technique; this statement is verified by the positive correlation between satisfaction with the appearance of the breasts and the overall post-surgical symmetry

Identification of recombination losses and charge collection efficiency in a perovskite solar cell by comparing impedance response to a drift-diffusion model.

Interpreting the impedance response of perovskite solar cells (PSCs) is significantly more challenging than for most other photovoltaics. This is for a variety of reasons, of which the most significant are the mixed ionic-electronic conduction properties of metal halide perovskites and the difficulty in fabricating stable, and reproducible, devices. Experimental studies, conducted on a variety of PSCs, produce a variety of impedance spectra shapes. However, they all possess common features, the most noteworthy of which is that they have at least two features, at high and low frequency, with different characteristic responses to temperature, illumination and electrical bias. The impedance response has commonly been analyzed in terms of sophisticated equivalent circuits that can be hard to relate to the underlying physics and which complicates the extraction of efficiency-determining parameters. In this paper we show that, by a combination of experiment and drift-diffusion (DD) modelling of the ion and charge carrier transport and recombination within the cell, the main features of common impedance spectra are well reproduced by the DD simulation. Based on this comparison, we show that the high frequency response contains all the key information relating to the steady-state performance of a PSC, i.e. it is a signature of the recombination mechanisms and provides a measure of charge collection efficiency. Moreover, steady-state performance is significantly affected by the distribution of mobile ionic charge within the perovskite layer. Comparison between the electrical properties of different devices should therefore be made using high frequency impedance measurements performed in the steady-state voltage regime in which the cell is expected to operate.

Understanding the Interfaces between Triple-Cation Perovskite and Electron or Hole Transporting Material.

The properties of efficient solar cells fabricated with triple-cation perovskite placed between a mesoporous titania layer and a spiro-OMeTAD layer are studied by using devices either prepared under water-free drybox conditions or fabricated under ambient room humidity. The morphological studies indicate that the content of unreacted PbI2 phase in the perovskite structure is much higher near the interface with titania than near the interface with spiro-OMeTAD. The stationary emission spectra and transient bleach peaks of perovskites show additional long-wavelength features close to the titania side. Time-resolved techniques ranging from femtoseconds to seconds reveal further differences in charge dynamics at both interfaces. The population decay is significantly faster at the titania side than at the spiro-OMeTAD side for the cells prepared under ambient conditions. An increased hole injection rate correlates with higher photocurrent seen in the devices prepared under drybox conditions. The charge recombination loss on the millisecond time scale is found to be slower at the interface with titania than at the interface with spiro-OMeTAD. The ideality factor of the cells is found to increase with increasing DMSO content in the precursor solution, indicating a change in recombination mechanism from bulk to surface recombination. We also found that the charge dynamics are not uniform within the whole perovskite layer. This feature has significant implications for understanding the operation and optimizing the performance of solar devices based on mixed cation perovskites.

Photochromic dye-sensitized solar cells with light-driven adjustable optical transmission and power conversion efficiency.

Semi-transparent photovoltaics only allows for the fabrication of solar cells with an optical transmission that is fixed during their manufacturing resulting in a trade-off between transparency and efficiency. For the integration of semi-transparent devices in building, ideally solar cells should generate electricity while offering the comfort for users to self-adjust their light transmission with the intensity of the daylight. Here we report a photochromic dye-sensitized solar cell (DSSC) based on donor-π-conjugated bridge-acceptor structures where the π-conjugated bridge is substituted for a diphenyl-naphthopyran photochromic unit. DSSCs show change in colour and self-adjustable light transmittance when irradiated with visible light and a power conversion efficiency up to 4.17%. The colouration-decolouration process is reversible and these DSSCs are stable over 50 days. We also report semi-transparent photo-chromo-voltaic mini-modules (23 cm2) exhibiting a maximum power output of 32.5 mW after colouration.