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1.
Phys Chem Chem Phys ; 26(21): 15268-15276, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38752312

RESUMEN

Transition metal oxides are pivotal in enhancing surface passivation and facilitating charge transfer (CT) in silicon based photonic devices, improving their efficacy and affordability through interfacial engineering. This study investigates TiO2/Si heterojunctions prepared by atomic layer deposition (ALD) with different pre-ALD chemical and post-ALD thermal treatments, exploring their influence on the surface passivation and the correlation with the CT at the TiO2-Si interface. Surface passivation quality is evaluated by the photoconductance decay method to study the effective carrier lifetime, while CT from Si to TiO2 is examined by transient reflectance spectroscopy. Surprisingly, the as-deposited TiO2 on HF-treated n-Si (without interfacial SiOx) demonstrates superior surface passivation with an effective lifetime of 1.23 ms, twice that of TiO2/SiOx/n-Si, and a short characteristic CT time of 200 ps, tenfold faster than that of TiO2/SiOx/n-Si. Post-ALD annealing at temperatures approaching the TiO2 crystallization onset re-introduces the SiOx layers in HF-treated samples and induces chemical and structural changes in all the samples which decrease passivation and prolong the CT time and are hence detrimental to the photonic device performance.

2.
Environ Res ; 261: 119671, 2024 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-39048068

RESUMEN

We explored the potential of carbon quantum dots (CQDs) as novel materials for wastewater treatment and their role towards environmental sustainability. The advantages of CQDs over other carbon-based materials, when synthesized using the same precursor material and for the same contaminant are discussed, enabling future researchers to choose the appropriate material. CQDs have demonstrated exceptional adaptability in various wastewater treatment, acting as efficient adsorbents for contaminants, exhibiting excellent photocatalytic properties for degradation of organic pollutants, and functioning as highly sensitive sensors for water quality monitoring. We found that bottom-up approach has better control over particle size (resulting CQDs: 1-4 nm), whereas top-down synthesis approach (resulting CQDs: 2-10 nm) have more potential for large scale applications and tunability. Transmission electron microscopy (TEM) remains the most expensive characterization technique, which provides the best resolution of the CQD's surface. The study emphasizes on the environmental impact and safety considerations pertaining to CQDs by emphasizing the need for thorough toxicity evaluation, and necessary environmental precautions. The study also identifies the lacunae pertaining to critical challenges in practical implementation of CQDs, such as scalability, competition of co-existing contaminants, and stability. Finally, future research directions are proposed, advocating green synthesis approaches, tailored surface functionalization, and, lowering the overall cost for analysis, synthesis and application of CQDs.


Asunto(s)
Carbono , Puntos Cuánticos , Aguas Residuales , Puntos Cuánticos/química , Carbono/química , Aguas Residuales/química , Aguas Residuales/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos
3.
Angew Chem Int Ed Engl ; 63(8): e202315747, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38179830

RESUMEN

A series of ferrocene(Fc)-bridged pentacene(Pc)-dimers [Fc-Ph(2,n)-(Pc)2 : n=number of phenylene spacers] were synthesized to examine the tortional motion effect of Fc-terminated phenylene linkers on strongly coupled quintet multiexciton (5 TT) formation through intramolecular singlet fission (ISF). Fc-Ph(2,4)-(Pc)2 has a relatively small electronic coupling and large conformational flexibility according to spectroscopic and theoretical analyses. Fc-Ph(2,4)-(Pc)2 exhibits a high-yield 5 TT together with quantitative singlet TT (1 TT) generation through ISF. This demonstrates a much more efficient ISF than those of other less flexible Pc dimers. The activation entropy in 1 TT spin conversion of Fc-Ph(2,4)-(Pc)2 is larger than those of the other systems due to the larger conformational flexibility associated with the torsional motion of the linkers. The torsional motion of linkers in 1 TT is attributable to weakened metal-ligand bonding in the Fc due to hybridization of the hole level of Pc to Fc in 1 TT unpaired orbitals.

4.
Blood ; 137(15): 2114-2124, 2021 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-33662988

RESUMEN

Monoclonal immunoglobulin G (IgG) antibodies to CD44 (anti-CD44) are anti-inflammatory in numerous murine autoimmune models, but the mechanisms are poorly understood. Anti-CD44 anti-inflammatory activity shows complete therapeutic concordance with IV immunoglobulin (IVIg) in treating autoimmune disease models, making anti-CD44 a potential IVIg alternative. In murine immune thrombocytopenia (ITP), there is no mechanistic explanation for anti-CD44 activity, although anti-CD44 ameliorates disease similarly to IVIg. Here, we demonstrate a novel anti-inflammatory mechanism of anti-CD44 that explains disease amelioration by anti-CD44 in murine ITP. Macrophages treated with anti-CD44 in vitro had dramatically suppressed phagocytosis through FcγRs in 2 separate systems of IgG-opsonized platelets and erythrocytes. Phagocytosis inhibition by anti-CD44 was mediated by blockade of the FcγR IgG binding site without changing surface FcγR expression. Anti-CD44 of different subclasses revealed that FcγR blockade was specific to receptors that could be engaged by the respective anti-CD44 subclass, and Fc-deactivated anti-CD44 variants lost all FcγR-inhibiting activity. In vivo, anti-CD44 functioned analogously in the murine passive ITP model and protected mice from ITP when thrombocytopenia was induced through an FcγR that could be engaged by the CD44 antibody's subclass. Consistent with FcγR blockade, Fc-deactivated variants of anti-CD44 were completely unable to ameliorate ITP. Together, anti-CD44 inhibits macrophage FcγR function and ameliorates ITP consistent with an FcγR blockade mechanism. Anti-CD44 is a potential IVIg alternative and may be of particular benefit in ITP because of the significant role that FcγRs play in human ITP pathophysiology.


Asunto(s)
Receptores de Hialuranos/inmunología , Inmunoglobulina G/inmunología , Púrpura Trombocitopénica Idiopática/inmunología , Receptores de IgG/inmunología , Animales , Plaquetas/inmunología , Femenino , Humanos , Inflamación/inmunología , Ratones , Ratones Endogámicos C57BL , Fagocitosis , Células RAW 264.7
5.
Blood ; 135(26): 2420-2424, 2020 06 25.
Artículo en Inglés | MEDLINE | ID: mdl-32374819

RESUMEN

Polyclonal anti-D is a first-line therapy for immune thrombocytopenia (ITP). Monoclonal antibodies are desirable alternatives, but none have yet proven successful despite their ability to opsonize erythrocytes (or red blood cells, RBCs) and cause anemia. Here, we examined 12 murine erythrocyte-specific antibodies of different specificity and subtypes and found that 8 of these antibodies could induce anemia in antigen-positive mice. Of these 8 antibodies, only 5 ameliorated ITP. All antibodies were examined for their in vitro ability to support macrophage-mediated phagocytosis of erythrocytes. Antibodies which supported erythrocyte phagocytosis in vitro successfully ameliorated ITP in vivo. To examine the ability of each antibody to inhibit phagocytosis of platelets, the antibodies were used to sensitize erythrocytes in vitro and these were added to a platelet phagocytosis assay. Antibodies that inhibited platelet phagocytosis in vitro also all ameliorated ITP in vivo. We conclude that inducing anemia is not a sufficient condition for amelioration of ITP but that the antibody's ability to prevent platelet phagocytosis in vitro predicted its ability to ameliorate ITP. We suggest that inhibition of in vitro platelet phagocytosis may prove to be a valuable tool for determining which erythrocyte antibodies would likely be candidates for clinical use in ITP.


Asunto(s)
Plaquetas , Eritrocitos/inmunología , Inmunoglobulina G/uso terapéutico , Fagocitosis , Púrpura Trombocitopénica Idiopática/sangre , Púrpura Trombocitopénica Idiopática/terapia , Anemia/etiología , Animales , Anticuerpos Monoclonales/efectos adversos , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/uso terapéutico , Femenino , Inmunoglobulina G/efectos adversos , Inmunoglobulina G/inmunología , Técnicas In Vitro , Ratones , Ratones Endogámicos C57BL , Fagocitosis/inmunología , Células RAW 264.7 , Ratas , Proteínas Recombinantes/efectos adversos , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/uso terapéutico
6.
Environ Res ; 204(Pt B): 112107, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34560058

RESUMEN

The COVID-19 pandemic lockdown supposedly provided a 'window' of reinstatement to natural resources including the air quality, but the scenario after the phased unlocking is yet to be explored. Consequently, here we evaluated the status of air quality during the 8th phase of unlocking of COVID-19 lockdown (January 2021) at three locations of North India. The first site (S1) was located at Punjab Agricultural University, Ludhiana-PPCB; the second site (S2) at Yamunapuram, Bulandshahr-UPPCB; and the third site (S3) at Okhla Phase-2, Delhi-DPCC. The levels of PM2.5 showed a significant increase of 525.2%, 281.2%, and 185.0% at sites S1, S2 and S3, respectively in the unlock 8 (January 2021), in comparison to its concentration in the lockdown phase. Coherently, the levels of PM10 also showed a prominent increase of 284.5%, 189.1%, and 103.9% at sites S3, S1, and S2, respectively during the unlock 8 as compared to its concentration in the lockdown phase. This rise in the concentration of PM2.5 and PM10 could be primarily attributed to the use of biomass fuel, industrial and vehicular emissions, stubble burning considering the agricultural activities at sites S1 and S2. Site S3 is a major industrial hub and has the highest population density among all three sites. Consequently, the maximum increase (295.7%) in the NO2 levels during the unlock 8 was witnessed at site S3. The strong correlation between PM2.5, PM10, and CO, along with the PM2.5/PM10 ratio confirmed the similar origin of these pollutants at all the three sites. The improvements in the levels of air quality during the COVID-19 lockdown were major overtaken during the various phases of unlocking consequent to the initiation of anthropogenic processes.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , COVID-19 , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Ciudades , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Humanos , India , Pandemias , Material Particulado/análisis , SARS-CoV-2
7.
Environ Monit Assess ; 195(1): 19, 2022 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-36279024

RESUMEN

The health risks associated with consumption of water from river Gomti polluted with potentially toxic elements (PTEs), including As, Fe, Pb, Cd, Mn, Cr, Ni, and Hg were investigated at the initiation of unlocking of COVID-19 lockdown and compared with pre-COVID-19 lockdown status. In the current investigation, the total hazard index (THI) values exceeded the acceptable limit of "unity" at all sampling stations. The use of river water for drinking and domestic purposes by millions of people with high THI values has emerged as a matter of huge concern. The individual hazard quotients associated with Cd and Pb were found to be most severe (> 1). A vivid difference between the THI values during the two study phases indicated the positive impact of COVID-19 lockdown signifying the prominent impact of anthropogenic activities on the PTE concentrations. The closure of local manufacturing units (textile, battery, etc.) emerged as a potential reason for decreased health risks associated with PTE levels. The higher susceptibility of children to health risks in comparison with adults through the values of THI and HQs was interpreted across the study area. Potential remedial measures for PTE contamination have also been suggested in the study.


Asunto(s)
COVID-19 , Mercurio , Metales Pesados , Nanoestructuras , Contaminantes del Suelo , Adulto , Niño , Humanos , Metales Pesados/análisis , Monitoreo del Ambiente , Cadmio , Plomo , Medición de Riesgo , Control de Enfermedades Transmisibles , Agua , Contaminantes del Suelo/análisis
8.
Environ Monit Assess ; 195(1): 10, 2022 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-36269455

RESUMEN

Phenol, an aromatic chemical commonly found in domestic and industrial effluents, upon its introduction into aquatic ecosystems adversely affects the indigenous biota, the invertebrates and the vertebrates. With the increased demand for agrochemicals, a large amount of phenol is released directly into the environment as a byproduct. Phenol and its derivatives tend to persist in the environment for longer periods which in turn poses a threat to both humans and the aquatic ecosystem. In our current study, the response of Labeo rohita to sublethal concentrations of phenol was observed and the results did show a regular decrease in biochemical constituents of the targeted organs. Exposure of Labeo rohita to sublethal concentration of phenol (22.32 mg/L) for an epoch of 7, 21 and 28 days shows a decline in lipid, protein, carbohydrate content and phosphatase activity in target organs such as the gills, muscle, intestine, liver and kidney of the fish. The present study also aims to investigate the toxic effects of phenol with special reference to the haematological parameters of Labeo rohita. At the end of the exposure period, the blood of the fish was collected by cutting the caudal peduncle with a surgical scalpel. And it was observed that the red blood corpuscle count (RBC), white blood corpuscle (WBC), haemoglobin count (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) values showed a decline after exposure to phenol for 7 days, while white blood corpuscle (WBC) shows an increased count. At 21 days and 28 days, all the haematological parameters showed a significant decrease.


Asunto(s)
Cyprinidae , Fenol , Contaminantes del Agua , Animales , Humanos , Agroquímicos , Carbohidratos , Cyprinidae/metabolismo , Ecosistema , Monitoreo del Ambiente , Agua Dulce/química , Hemoglobinas/metabolismo , Lípidos , Fenol/toxicidad , Monoéster Fosfórico Hidrolasas/metabolismo , Contaminantes del Agua/química , Contaminantes del Agua/toxicidad
9.
Environ Monit Assess ; 195(1): 12, 2022 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-36271213

RESUMEN

The goal of this study was to come up with an efficient method for treating cheese production wastewater. Because the effluent has a higher concentration of organic and inorganic materials, the indigenous microbial treatment process was used to effectively remove total dissolved solids (TDS), chemical oxygen demand (COD), and color without the addition of any nutrients. The indigenous microorganisms were tested for color, TDS, and COD elimination by growing them in "nutrient broth medium" loaded with different amounts of cheese effluent. The isolates were identified by 16S rRNA sequencing, and the results revealed that strain 1 was Enterobacter cloacae, strain 2 was Lactococcus garvieae, and strains 3 and 4 were Bacillus cereus and Bacillus mycoides, respectively. After 36 h of incubation, the data were evaluated. Among all the microbes, E. cloacae reduced TDS and COD from the effluent the most (80 ± 0.2% and 87 ± 0.4% COD, respectively). When compared to individual species, consortia were more efficient (86 ± 0.2% TDS and 90 ± 0.3% COD). On treatment, the correlation coefficient "r" for TDS and COD elimination was found to be 1, resulting in a positive linear connection. The current study suggests that microbial therapies are both effective and environmentally beneficial.


Asunto(s)
Queso , Contaminantes Ambientales , Monitoreo del Ambiente , ARN Ribosómico 16S , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/química
10.
Phys Chem Chem Phys ; 23(32): 17672-17682, 2021 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-34373878

RESUMEN

Polycrystalline titanium dioxide thin films are routinely used in a broad range of applications where charge carrier lifetime is essential for their performance but the effects of the fabrication method are rarely considered. Here we compare three popular deposition methods, atomic layer deposition (ALD), ion beam sputtering (IBS), and spray pyrolysis deposition (SPD). In all three cases, 30 nm thin films of TiO2 are prepared, and the as-deposited films show no defined crystal structure and can be classified as amorphous films. Heat treatment (HT) of the films converts all of them to polycrystalline anatase TiO2 as revealed by XRD measurements. A photophysical study was carried out by pico- to nano-second transient absorption pump-probe spectroscopy in transmittance and reflectance modes which allows taking into account the effects due to the photoinduced refractive index changes. This study shows that the HT increases the lifetime of the photo-carriers gradually to a nanosecond time domain (approx. 4 ns) as compared to a few picoseconds of the as-deposited samples. The photo-carrier dynamics of the samples become very similar after heat-treatment, though the topographical features and texture of the films observed with AFM and XRD are quite different. The measured transient absorption spectra of the samples also indicate that the photo-carrier relaxation pathway involves electron and hole trap states with the longest-lived being the hole traps. To evaluate the photoactivity of thin films, methylene blue (MB) photodegradation was tested for all the as-deposited and HT samples and the results showed a 20% higher degradation rate for the IBS HT sample due to the more textured surface.

11.
Transfus Apher Sci ; 59(1): 102710, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31926738

RESUMEN

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare neonatal disorder that is caused by alloimmunization against platelet antigens during pregnancy. Although rare, affecting only 1 in 1000 live births, it can cause intracranial hemorrhage and other bleeding complications that can lead to miscarriage, stillbirth and life-long neurological complications. One of the gold-standard therapies for at risk pregnancies is the administration of IVIg. Although IVIg has been used in a variety of different disorders for over 40 years, its exact mechanism of action is still unknown. In FNAIT, the majority of its therapeutic effect is thought the be mediated through the neonatal Fc receptor, however other mechanisms cannot be excluded. Due to safety, supply and other concerns that are associated with IVIg use, alternative therapies that could replace IVIg are additionally being investigated. This includes the possibility of a prophylaxis regimen for FNAIT, similarly to what has been successfully used in hemolytic disease of the fetus and newborn for over 50 years.


Asunto(s)
Inmunoglobulinas Intravenosas/uso terapéutico , Trombocitopenia Neonatal Aloinmune/inmunología , Femenino , Feto , Humanos , Recién Nacido , Embarazo
12.
AJR Am J Roentgenol ; 207(5): 947-951, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27610583

RESUMEN

OBJECTIVE: Ongoing controversy regarding screening mammography guidelines has created confusion for many patients. Given recommendations that patient educational material be prepared at or below the 7th grade reading level of average Americans, the purpose of this study was to assess the readability of online mammography information offered by hospitals nationwide. MATERIALS AND METHODS: During 2015, online mammography patient educational materials were identified for all Medicare-recognized hospitals nationwide for which screening mammography metrics were publicly available. Patient educational materials were assessed using six validated readability score algorithms. All references to official screening guidelines were captured. RESULTS: Of 4105 hospitals nationwide, 3252 had websites and confirmable screening mammography services. Of those, 1753 (54%) offered mammography information material online. Only 919 (28%) referenced any professional society guidelines. After excluding information not formatted in HTML and shorter than 100 words (to improve algorithm reliability), 1524 hospital mammography webpages were assessed for grade level scores. Nationally, the mean of each readability score for all hospitals varied between the 10th and 14th grade levels, all higher than the recommended 7th grade level (p < 0.001). At the individual hospital level, only 14 hospitals (0.4%) had mean scores at or below the 7th grade level. CONCLUSION: Of U.S. hospitals that offer screening mammography and have websites, only 54% provide online mammography educational material. Of those, only 0.4% present information at a reading level comprehensible to average Americans, and only 28% offer specific information to help patients reconcile conflicting guidelines. Health systems offering mammography should strive to better meet women's health information and literacy needs.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Internet , Mamografía , Educación del Paciente como Asunto , Algoritmos , Comprensión , Femenino , Hospitales , Humanos , Guías de Práctica Clínica como Asunto , Estados Unidos
13.
J Vasc Interv Radiol ; 26(8): 1156-61, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26074029

RESUMEN

PURPOSE: To assess the readability of online education materials offered by hospitals describing commonly performed interventional radiology (IR) procedures. MATERIALS AND METHODS: Online patient education materials from 402 hospitals selected from the Medicare Hospital Compare database were assessed. The presence of an IR service was determined by representation in the Society of Interventional Radiology physician finder directory. Patient online education materials about (i) uterine artery embolization for fibroid tumors, (ii) liver cancer embolization, (iii) varicose vein treatment, (iv) central venous access, (v) inferior vena cava (IVC) filter placement, (vi) nephrostomy tube insertion, (vii) gastrostomy tube placement, and (viii) vertebral augmentation were targeted and assessed by using six validated readability scoring systems. RESULTS: Of 402 hospitals sampled, 156 (39%) were presumed to offer IR services. Of these, 119 (76%) offered online patient education material for one or more of the eight service lines. The average readability scores corresponding to grade varied between the ninth- and 12th-grade levels. All were higher than the recommended seventh-grade level (P < .05) except for nephrostomy and gastrostomy tube placement. Average Flesch-Kincaid Reading Ease scores ranged from 42 to 69, corresponding with fairly difficult to difficult readability for all service lines except IVC filter and gastrostomy tube placement, which corresponded with standard readability. CONCLUSIONS: A majority of hospitals offering IR services provide at least some online patient education material. Most, however, are written significantly above the reading comprehension level of most Americans. More attention to health literacy by hospitals and IR physicians is warranted.


Asunto(s)
Instrucción por Computador/estadística & datos numéricos , Conocimientos, Actitudes y Práctica en Salud , Alfabetización en Salud/estadística & datos numéricos , Hospitales/estadística & datos numéricos , Educación del Paciente como Asunto/estadística & datos numéricos , Radiología Intervencionista/educación , Comprensión , Evaluación Educacional , Internet , Sistemas en Línea , Radiografía Intervencional/estadística & datos numéricos , Lectura , Estados Unidos
14.
AJR Am J Roentgenol ; 205(5): W542-9, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26496576

RESUMEN

OBJECTIVE: The purpose of this study was to assess the effectiveness and safety of air versus liquid enema reduction in the treatment of intussusception in children. MATERIALS AND METHODS: Literature searches of the PubMed, Embase, and Cochrane Library databases were conducted from January 1, 1966, through May 31, 2013. Articles on the use of air or liquid enema in children with a confirmed diagnosis of intussusception and reporting either a success rate for enema reduction of intussusception or a perforation rate were selected. Enema reduction success rate, perforation rate, and recurrence rate were the main outcomes and were calculated by random effects modeling. RESULTS: One hundred two articles (101 reporting success rate, 71 reporting perforation rate) were included that presented results for 32,451 children (age range, 1 day-22 years; boys, 66%; girls, 34%). In 44 studies (16,187 children), the combined estimate for success rate of air enema was 82.7% (95% CI, 79.9-85.6%; inconsistency index [I(2)] = 97%), and in 52 studies (13,081 children) of liquid enema, it was 69.6% (95% CI, 65.0-74.1%; I(2) = 98%). In 38 studies (15,752 children), the combined estimate of perforation rate for air enema was 0.39% (95% CI, 0.23- 0.55%; I(2) = 40%), and in 30 studies (9429 children) of liquid enema, it was 0.43% (95% CI, 0.24- 0.62%; I(2) = 9%). Among 10,494 children (26 studies) undergoing air enema reduction, the rate of first intussusception recurrence was 6% (95% CI, 4.5-7.5%; I(2) = 89%), similar to the 7.3% (95% CI, 5.8-8.8%; I(2) = 71%) found for 4004 children (24 studies) undergoing liquid enema reduction. CONCLUSION: Air enema was superior to liquid enema for intussusception reduction. The success rate was higher without a difference in perforation rate. Limitations included heterogeneity and publication bias.


Asunto(s)
Aire , Enema , Intususcepción/terapia , Adolescente , Niño , Preescolar , Humanos , Lactante , Recién Nacido
15.
J Phys Chem C Nanomater Interfaces ; 128(15): 6167-6179, 2024 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-38655057

RESUMEN

Transient absorption spectroscopy is a powerful technique to study the photoinduced phenomena in a wide range of states from solutions to solid film samples. It was designed and developed based on photoinduced absorption changes or that photoexcitation triggers a chain of reactions with intermediate states or reaction steps with presumably different absorption spectra. However, according to general electromagnetic theory, any change in the absorption properties of a medium is accompanied by a change in the refractive properties. Although this photoinduced change in refractive index has a negligible effect on solution measurements, it may significantly affect the measured response of thin films. In this Perspective paper, we examine why and how the measured responses of films differ from their expected "pure" absorption responses. The effect of photoinduced refractive index change can be concluded and studied by comparing the transmitted and reflected probe light responses. Another discussed aspect is the effect of light interference on thin films. Finally, new opportunities of monitoring the photocarrier migration in films and studying nontransparent samples using the reflected probe light response are discussed. Most of the examples provided in this article focus on studies involving perovskite, TiO2, and graphene-based films, but the general discussion and conclusions can be applicable to a wide range of semiconductor and thin metallic films.

16.
J Phys Chem Lett ; 15(7): 2057-2065, 2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-38357864

RESUMEN

The kinetics of electron extraction at the electron transfer layer/perovskite interface strongly affects the efficiency of a perovskite solar cell. By combining transient absorption and time-resolved photoluminescence spectroscopy, the electron extraction process between FA0.83Cs0.17Pb(I0.83Br0.17)3 and TiO2 single crystals with different orientations of (100), (110), and (111) were probed from subpicosecond to several hundred nanoseconds. It was revealed that the band alignment between the constituents influenced the relative electron extraction process. TiO2(100) showed the fastest overall and hot electron transfer, owing to the largest conduction band and Fermi level offset compared to FA0.83Cs0.17Pb(I0.83Br0.17)3. It was found that an early electron accumulation in these systems can have an influence on the following electron extraction on the several nanosecond time scale. Furthermore, the existence of a potential barrier at the TiO2/perovskite interface was also revealed by performing excitation fluence-dependent measurements.

17.
Sci Adv ; 10(37): eadn7763, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-39270030

RESUMEN

Molecular assemblies featuring two-dimensionality have attracted increasing attention, whereas such structures are difficult to construct simply relying on spontaneous molecular assembly. Here, we present two-dimensional assemblies of acene chromophores achieved using a tripodal triptycene supramolecular scaffold, which have been shown to exhibit a strong ability to assemble molecular and polymer motifs two-dimensionally. We designed pentacene and anthracene derivatives sandwiched by two triptycene units. These compounds assemble into expected two-dimensional structures, with the pentacene chromophores having both sufficient overlap to cause singlet fission and space for conformational change to facilitate the dissociation of a triplet pair into free triplets, which is not the case for the anthracene analog. Detailed spectroscopic analysis revealed that the pentacene chromophore in the assembly undergoes singlet fission with a quantum yield of 88 ± 5%, giving rise to triplet pairs, from which free triplets are efficiently generated (ΦT = 130 ± 8.8%). This demonstrates the utility of the triptycene-based scaffold to design functional π-electronic molecular assemblies.

18.
Adv Biol (Weinh) ; : e2400308, 2024 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-39410834

RESUMEN

Developing bioinspired materials to convert sunlight into electricity efficiently is paramount for sustainable energy production. Fluorescent proteins are promising candidates as photoactive materials due to their high fluorescence quantum yield and absorption extinction coefficients in aqueous media. However, developing artificial bioinspired photosynthetic systems requires a detailed understanding of molecular interactions and energy transfer mechanisms in the required operating conditions. Here, the supramolecular self-assembly and photophysical properties of fluorescent proteins complexed with organic dyes are investigated in aqueous media. Supercharged mGreenLantern protein, mutated to have a charge of +22, is complexed together with anionic zinc phthalocyanines having 4 or 16 carboxylate groups. The structural characterization reveals a strong electrostatic interaction between the moieties, accompanied by partial conformational distortion of the protein structure, yet without compromising the mGreenLantern chromophore integrity as suggested by the lack of emission features related to the neutral form of the chromophore. The self-assembled biohybrid shows a total quenching of protein fluorescence, in favor of an energy transfer process from the protein to the phthalocyanine, as demonstrated by fluorescence lifetime and ultrafast transient absorption measurements. These results provide insight into the rich photophysics of fluorescent protein-dye complexes, anticipating their applicability as water-based photoactive materials.

19.
Curr Mol Med ; 2024 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-38984570

RESUMEN

BACKGROUND: Increased expression of MRP 1 in AML patients results in the efflux of drugs from the cells, preventing the patient from achieving remission or potentially leading to relapse. Several studies have demonstrated that early identification of ABC transporter may yield favorable outcomes. AIMS AND OBJECTIVES: The objectives of the study were to investigate the correlation between MRP 1 gene expression and MRP 1 protein levels and the response to remission induction in AML patients. METHOD: A total of 40 AML patients were recruited from March 2021 to June 2022. Peripheral blood was collected in two tubes (yellow and purple top) to assess the MRP 1 gene and protein. For MRP 1 gene assessment, RNA was isolated from blood samples, cDNA was prepared, and qRT-PCR was performed to analyze gene expression. The relationship between the gene and complete remission was determined. Identification of MRP 1 protein was conducted using ELISA, and the relationship between protein levels and complete remission (CR) was explored. RESULTS: Most of the patients were aged between 25 and 39 years, encompassing both males and females. This study observed a clinical correlation between MRP 1 gene expression and complete remission. The findings revealed that 69.2 percent of patients with high gene expression failed to achieve complete remission, whereas the analysis of MRP 1 protein in relation to complete remission showed no statistical significance. The MRP1 gene showed high expression (66.7%) in patients with FLT3 mutation, whereas low expression of MRP1 was associated with a high occurrence (60%) of NMP1 mutation. CONCLUSION: Further comprehensive multicenter studies with larger sample sizes are required to validate the findings of this study. It is recommended to pinpoint the mechanism and regulation of MRP 1 and its interaction with other molecular pathways.

20.
Artículo en Inglés | MEDLINE | ID: mdl-37043124

RESUMEN

Nature-based solutions (NBSs) for remediation of various emerging contaminants have gained impetus during the last few decades. In the current study, watermelon (citrullus lanatus), a highly consumed seasonal fruit, was used as a feedstock waste biomass for biochar synthesis through valorization of watermelon rinds. The watermelon biochar (WM-BC) was synthesized through slow pyrolysis at 550°C under anoxic conditions. Langmuir model with R2>99, was found to best fit the adsorption isotherm, and the adsorption kinetics was best described by the pseudo-second-order model. Various characterization tools including FTIR, SEM, BET, XRD, and TEM were used to evaluate the surface morphology of the biochar. The removal efficiency increased from 35% (dosage = 0.4 g), to 81% at WM-BC dosage of 2 g. A maximum adsorption capacity of 115.61 mg/g was found. The results from kinetic and isotherm model model suggested that the adsorption was favorable and multilayer adsorption can be considered. The adsorption mechanism was found to be governed by the co-existing factors such as hydrogen bonding, electrostatic interactions, and aromatic interactions. Results suggest that WM-BC has high potential to be employed as an adsorbent for efficient remediation of methylene blue dyes from aqueous solutions.

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