Lead-Free Metal Halide Perovskite Nanocrystals: From Fundamentals to Applications.

Lead (Pb) halide perovskite nanocrystals, with the general formula APbX3 , where A=CH3 NH3+ , CH(NH2 )2+ , or Cs+ and X=Cl- , Br- , or I- , have emerged as a class of materials with promising properties due to their remarkable optical properties and solar cell performance. However, important issues still need to be addressed to enable practical applications of these materials, such as instability, mass production, and Pb toxicity. Recent studies have carried out the replacement of Pb by various less-toxic cations as Sn, Ge, Sb, and Bi. This variety of chemical compositions provide Pb-free perovskite and metal halide nanostructures with a wide spectral range, in addition to being considered less toxic, therefore having greater practical applicability. Highlighting the necessity to address and solve the toxicity problems related to Pb-containing perovskite, this review considers the prospects of the Pb-free perovskite, involving synthesis methods, and properties of them, including advantages, disadvantages, and applications.

Probing the cw-Laser-Induced Fluorescence Enhancement in CsPbBr3 Nanocrystal Thin Films: An Interplay between Photo and Thermal Activation.

Perovskite nanocrystals hold significant promise for a wide range of applications, including solar cells, LEDs, photocatalysts, humidity and temperature sensors, memory devices, and low-cost photodetectors. Such technological potential stems from their exceptional quantum efficiency and charge carrier conduction capability. Nevertheless, the underlying mechanisms of photoexcitation, such as phase segregation, annealing, and ionic diffusion, remain insufficiently understood. In this context, we harnessed hyperspectral fluorescence microspectroscopy to advance our comprehension of fluorescence enhancement triggered by UV continuous-wave (cw) laser irradiation of CsPbBr3 colloidal nanocrystal thin films. Initially, we explored the kinetics of fluorescence enhancement and observed that its efficiency (φph) correlates with the laser power (P), following the relationship φph = 7.7⟨P⟩0.47±0.02. Subsequently, we estimated the local temperature induced by the laser, utilizing the finite-difference method framework, and calculated the activation energy (Ea) required for fluorescence enhancement to occur. Our findings revealed a very low activation energy, Ea ∼ 9 kJ/mol. Moreover, we mapped the fluorescence photoenhancement by spatial scanning and real-time static mode to determine its microscale length. Below a laser power of 60 µW, the photothermal diffusion length exhibited nearly constant values of approximately (22 ± 5) µm, while a significant increase was observed at higher laser power levels. These results were ascribed to the formation of nanocrystal superclusters within the film, which involves the interparticle spacing reduction, creating the so-called quantum dot solid configuration along with laser-induced annealing for higher laser powers.

As principais complicações em cirurgias plásticas em pacientes pós-bariátrica: Uma revisão integrativa da literatura / The main complications in plastic surgery in post-bariatric patients: An integrative review of the literature

Introdução: As intervenções cirúrgicas pós-bariátricas vêm se tornando cada vez mais frequentes e englobam a abdominoplastia, a cirurgia plástica interna da coxa, a braquioplastia e a mastopexia. Porém, devido ao caráter disabsortivo e restritivo do paciente bariátrico, esse estudo tem como objetivo apresentar as complicações advindas de procedimentos estéticos realizados nestes pacientes, expondo os fatores de risco mais associados às sequelas e levantando opções para um melhor desfecho. Método: Foi realizada uma revisão integrativa da literatura, de caráter qualitativo, segundo a pergunta norteadora: "Quais as principais complicações em cirurgias plásticas realizadas em pacientes bariatricados?". A busca foi realizada nas plataformas Biblioteca Virtual de Saúde (BVS) e PubMed. Os artigos incluídos no estudo foram analisados pelo método de conteúdo. Resultados: No total foram incluídos 6 artigos, nos quais observou-se que as principais complicações de cirurgias de contorno corporal, tais como a abdominoplastia e a braquioplastia, em pacientes bariatricados foram, principalmente, deiscência de feridas, seromas e hematomas, complicações, essas, relacionadas principalmente ao índice de massa corporal (IMC) do paciente, às suas comorbidades e ao tabagismo. Conclusão: Percebe-se, hoje, uma maior demanda pelas cirurgias plásticas reparadoras pósbariátrica, principalmente pela abdominoplastia. Consequentemente, houve, também, um aumento no número de complicações intraoperatórias, destacando-se o seroma e a deiscência de feridas. Para amenizá-las, a melhor solução é trabalhar no controle de fatores de risco pré-operatórios do paciente, tais como o IMC elevado e o tabagismo, além de comorbidades que levam à deficiência de cicatrização.

Introduction: Post-bariatric surgical interventions have become increasingly frequent, including abdominoplasty, inner thigh plastic surgery, brachioplasty, and mastopexy. However, due to bariatric patients' malabsorptive and restrictive nature, this study aims to present complications arising from aesthetic procedures performed on these patients, exposing the risk factors most associated with sequelae and raising options for a better outcome. Method: An integrative qualitative literature review was carried out according to the guiding question: "What are the main complications in plastic surgeries performed on bariatric patients?". The search was conducted on the Biblioteca Virtual de Saúde (BVS) and PubMed platforms. The articles included in the study were analyzed using the content method. Results: In total, 6 articles were included, in which it was observed that the main complications of body contouring surgeries, such as abdominoplasty and brachioplasty, in bariatric patients were mainly wound dehiscence, seromas and hematomas, complications, these, mainly related to the patient's body mass index (BMI), their comorbidities and smoking. Conclusion: Today, there is a greater demand for post-bariatric reconstructive plastic surgery, especially abdominoplasty. Consequently, there was also an increase in intraoperative complications, notably seroma and wound dehiscence. To alleviate them, the best solution is to work on controlling the patient's preoperative risk factors, such as high BMI and smoking, as well as comorbidities that lead to poor healing.