10,602 research outputs found
The parameters of POS, CS, SCA, FPA, FA, LWFA.
No full textThe parameters of POS, CS, SCA, FPA, FA, LWFA.</p
The Effect of Ferulic Acid-Grafted Chitosan (FA-g-CS) on the Transmembrane Transport of Anthocyanins by sGLT1 and GLUT2
No full textThis work aims to evaluate the effect of ferulic acid-grafted chitosan (FA-g-CS) on the interaction between anthocyanin (ANC) and sGLT1/GLUT2 and their functions in ANC transmembrane transport using Caco-2 cells. The transmembrane transport experiments of ANC showed its low transport efficiency (Papp < 10−6 cm/s), whereas the phenomenon of a significantly rise in anthocyanins transport efficiency was observed with the incubation of FA-g-CS (p < 0.05). In order to investigate the mechanism of FA-g-CS improving ANC transmembrane transport, Caco-2 cells were transfected with small interfering RNA (siRNA) specific for transporters sGLT1 and GLUT2, and incubated with ANC, FA-g-CS, or their combination. Subsequently, Western blot analyses and immunofluorescence staining were carried out to monitor the intracellular sGLT1 and GLUT2 levels. These siRNA-transfected cells, incubated with compounds, indicate that sGLT1 and GLUT2 participated in the ANC transmembrane transport and that FA-g-CS, ANC, or their combination enhance sGLT1/GLUT2 expression. In particular, Caco-2 cells incubated with both FA-g-CS and ANC show significantly increased sGLT1 or GLUT2 expression (>80%) compared with exclusively using FA-g-CS or ANC (<60%). Molecular docking results demonstrate that there is a good binding between FA-g-CS/ANC and sGLT1 or GLUT2. These results highlight that FA-g-CS promotes the transmembrane transport of ANC by influencing the interaction between ANC and sGLT1/GLUT2; the interaction between FA-g-CS and ANC could be another key factor that improves the bioavailability of ANC
MA Cation-Induced Diffusional Growth of Low-Bandgap FA-Cs Perovskites Driven by Natural Gradient Annealing
No full textLow-bandgap formamidinium-cesium (FA-Cs) perovskites of FA1-xCsxPbI3 (x<0.1) are promising candidates for efficient and robust perovskite solar cells, but their black-phase crystallization is very sensitive to annealing temperature. Unfortunately, the low heat conductivity of the glass substrate builds up a temperature gradient within from bottom to top and makes the initial annealing temperature of the perovskite film lower than the black-phase crystallization point (~150°C). Herein, we take advantage of such temperature gradient for the diffusional growth of high-quality FA-Cs perovskites by introducing a thermally unstable MA+ cation, which would firstly form α-phase FA-MA-Cs mixed perovskites with low formation energy at the hot bottom of the perovskite films in the early annealing stage. The natural gradient annealing temperature and the thermally unstable MA+ cation then lead to the bottom-to-top diffusional growth of highly orientated α-phase FA-Cs perovskite, which exhibits 10-fold of enhanced crystallinity and reduced trap density (~3.85×1015 cm−3). Eventually, such FA-Cs perovskite films were fabricated into stable solar cell devices with champion efficiency up to 23.11%, among the highest efficiency of MA-free perovskite solar cells
Effect of dietary butter (CON), chia seed (CS) and pumpkin seed (PS) on FA profile (g /100 g FA total methyl ester) in sheep milk.
No full textEffect of dietary butter (CON), chia seed (CS) and pumpkin seed (PS) on FA profile (g /100 g FA total methyl ester) in sheep milk.</p
Protective Effects of Zein/Ferulic Acid (FA)–Pectin (PEC)/Chitosan (CS) Nanocomplexes on DSS-Induced Ulcerative Colitis in Mice
No full textFerulic acid (FA) exhibits beneficial properties in ulcerative colitis (UC) pathogenesis, while sensitivity to the environment and enzymes limits its use in UC therapy. Therefore, this study aims to develop a colon-targeted nanocomplex delivery system using FA and investigate its protective effects and underlying regulatory mechanisms in UC mice. A novel Zein/FA–pectin (PEC)/chitosan (CS) nanocomplex was successfully fabricated in this study. Through systematic adjustment of the PEC/CS-to-Zein/FA ratio, optimal encapsulation efficiency (60.1%) and loading capacity (26.2%) were achieved. The characterized data indicated that hydrogen bonds, electrostatic interactions, and hydrophobic forces were the main driving forces maintaining the formation of the nanocomplexes, accompanied by alterations in the secondary structure of Zein. The Zein/FA–PEC/CS nanocomplexes demonstrated excellent thermal/storage particle size stability and exhibited both protective and sustained-release effects of FA during simulated gastrointestinal digestion. Furthermore, the results demonstrated that the nanocomplexes potentially alleviate UC by regulating inflammatory cytokines, oxidative stress, and gut microbiota. Compared to unencapsulated FA, the nanocomplexes have a better effect on alleviating UC symptoms. In summary, Zein/FA–PEC/CS nanocomplexes have promising prospects in alleviating colitis in UC mice
Reduced sensitivity of fa/fa Zucker rats to adrenomedullin
No full textRat adrenomedullin is a peptide vasodepressor that may be of importance in the pathogenesis of hypertensive disease. Because of the known link between obesity and hypertension, we hypothesized that decreased responsiveness to adrenomedullin might be seen in an obese rodent model. In this study, the in vivo vasodilator actions of exogenous adrenomedullin were compared in anesthetized lean (n = 7) and obese (fa/fa) Zucker rats (n = 8). Adrenomedullin dose dependently lowered mean arterial pressure in both phenotypes, but the half-maximal dose (ID50) was 2-fold higher in fa/fa rats (1.7 +/- 0.22 vs. 0.83 +/- 0.06 nmol/kg). Moreover, the duration of effect was markedly reduced in the fa/fa rats, to 1-2 min from about 5 min in the lean animals. There was no evidence for an increased rate of degradation of adrenomedullin in the fa/fa rats. Although the rats used in this study were not hypertensive, adrenomedullin had reduced sensitivity and duration of action. The evidence suggests possible defects at the target receptor or altered metabolism of adrenomedullin in obesity.LR: 20061115; PUBM: Print; JID: 0372712; 0 (Peptides); 0 (Vasodilator Agents); 148498-78-6 (Adrenomedullin); ppublishSource type: Electronic(1
Studi Pengaruh Variasi Cs Terhadap Kestabilan Energi Celah Pita Pada Perovskit MA(1-x)Cs(x)SnI3 Dan FA(1-x)Cs(x)SnI3 Dengan Variasi Konsentrasi X=0;0,25;0,5;0,75;1
No full textPerovskit berbasis timah (Sn-based perovskite) merupakan kandidat material potensial untuk sel surya generasi baru karena memiliki mobilitas pembawa muatan tinggi dan energi celah pita yang sesuai untuk konversi energi matahari. Namun, material ini masih menghadapi tantangan utama berupa stabilitas termal dan kimia yang rendah akibat oksidasi Sn²⁺ menjadi Sn⁴⁺, yang mempercepat degradasi material. Salah satu strategi untuk meningkatkan kestabilan perovskit timah adalah penambahan ion Cesium (Cs⁺), yang dapat memperkuat struktur kristal dan meningkatkan ketahanan terhadap kelembaban. Penelitian ini bertujuan untuk menganalisis pengaruh penambahan Cs terhadap kestabilan fasa dan energi celah pita pada perovskit MA(1-x)CsxSnI₃ dan FA(1-x)CsxSnI₃ dengan variasi Cs (x = 0; 0.25; 0.5; 0.75; dan 1). Sintesis dilakukan menggunakan metode larutan dengan pelarut dimetilformamida (DMF), sedangkan karakterisasi mencakup XRD, Vis Spectroscopy, dan SEM. Hasil penelitian ini menunjukkan bahwa penambahan Cs memang dapat memperbaiki performa dari perovskit dibuktikan dengan sampel yang diberi tambahan Cs lebih tahan lama dan tidak cepat mengalami degradasi. Namun penambahan Cs yang terlalu berlebih juga dapat menganggu kestabilan sampel perovskit, dibuktikan dengan hasil vis-spektrofotometer dengan konsentrasi Cs sebesar 75% pada sampel FASnI3 celah pita tidak langsung nya lebih besar dibandingkan dengan yang dilakukan penambahan Cs sebesar 25%. Dari hasil XRD yang dilakukan menunjukkan hasil bahwa sampel FA lebih baik peformanya dari sampel MA, dibuktikan bahwa lebih banyak terbentuk fasa perovskite tunggal dalam sampel FA-25Cs. ========================================================================================================================================
Tin-based perovskite (Sn-based perovskite) is a promising material for next-generation solar cells due to its high charge carrier mobility and suitable bandgap energy for solar energy conversion. However, this material faces major challenges related to low thermal and chemical stability, mainly due to the oxidation of Sn²⁺ to Sn⁴⁺, which accelerates material degradation. One approach to enhance the stability of tin-based perovskites is Cesium (Cs⁺) addition, which can strengthen the crystal structure and improve resistance to moisture and environmental degradation. This study aims to analyze the effect of Cs addition on phase stability and bandgap energy in MA(1-x)CsxSnI₃ and FA(1-x)CsxSnI₃ perovskites with Cs variations (x = 0; 0.25; 0.5; 0.75 and 1). The synthesis was conducted using a solution-based method with dimethylformamide (DMF) as the solvent, while characterization included XRD, Vis Spectroscopy, and SEM. The results of this study indicate that the addition of Cs can indeed improve the performance of the perovskite, as evidenced by the samples with added Cs being more durable and less prone to degradation. However, an excessive amount of Cs can disrupt the stability of the perovskite sample, as shown by the UV-Vis spectrophotometer results, where the sample with 75% Cs concentration in FASnI₃ exhibited a larger indirect band gap compared to the sample with 25% Cs. XRD analysis also revealed that the FA-based sample outperformed the MA-based sample, as indicated by the greater formation of a single perovskite phase in the FA-25Cs sample
Chemical Distribution of Multiple Cation Rb , Cs , MA , and FA Perovskite Materials by Photoelectron Spectroscopy
No full textLead-based mixed perovskite materials have emerged in the last couple of years as promising photovoltaic materials. Recently, it was shown that improved material stability can be achieved by incorporating small amounts of inorganic cations (Cs+ and Rb+), partially replacing the more common organic cations (e.g., methylammonium, MA, and formamidinium, FA). Especially, a mixed cation composition containing Rb+, Cs+, MA(+), and FA(+) was recently shown to have beneficial optoelectronic properties and was stable at elevated temperature. This work focuses on the composition of this material using synchrotron-based photoelectron spectroscopy. Different probing depths were considered by changing the photon energy of the X-ray source providing insights on the chemical composition and the chemical distribution near the surface of the samples. Perovskite materials containing two, three, or four monovalent cations were analyzed and compared. The presence of Cs and Rb was observed both at the sample surface and toward the bulk, and we found that in the presence of three or four cations, less unreacted PbI2 remains in the sample. Interestingly, Rb and Cs appear to act jointly resulting in a different cation depth profile compared to that of the triple counterparts. Our findings provide significant understanding of the intricate depth-dependent chemical composition in perovskite materials using the common practice of cation mixing.LP
Alloy [FA,Cs]PbI₃ perovskite surfaces. The role of surface cesium composition in stability and tolerance to defect formation
No full textHalide-perovskite alloys that include cesium have achieved records of stability and efficiency in solar cells.
Controlling the surface composition, defects, and electronic properties guarantees interface stability and
improves performance. By using density functional theory and molecular dynamic simulations, we analyzed
which surface compositions of the formamidinium (FA) and cesium (Cs) lead iodide perovskite FA₁₋ₓCsₓPbl₃
with 25 and 50% of Cs become more stable than pure perovskites. Structural and electronic properties and
tolerance to defect formation were also evaluated. Surface energy calculations show that only the alloys with
25% Cs and F Al-enriched surfaces are more stable than pure FAPbl₃ ones. The most stable alloy surface shows
electronic energy levels similar to the FAPbl₃ perovskite, suggesting that this alloy may also be efficient for
charge transport in the cell. However, the presence of Cs on the alloy surface, although low, favors the
formation of FAI vacancies, which is detrimental to the stability of the perovskite. These results suggest
evaluating FA₁₋ₓCsₓPbl₃ alloys with small Cs compositions to mitigate the formation of defects or using
a passivation scherne. This study delivers valuable information for efficiency device improvement from the
perspective of interface stability
Temperature-dependent studies of exciton binding energy and phase-transition suppression in (Cs,FA,MA)Pb(I,Br)<sub>3</sub> perovskites
Get PDF\ua9 2019 Author(s). Multiple-cation mixed-halide (Cs,FA,MA)Pb(I,Br) 3 perovskites containing cesium, formamidinium (FA), and methylammonium (MA) possess excellent properties for a wide range of optoelectronic applications such as thin-film photovoltaics or lasers. We investigate the role of excitons and the exciton binding energy E B , relevant for the effectiveness of charge separation in solar cells, as well as the temperature-dependent bandgap energy E g which is used as an indicator for crystal phase transitions. Generalized Elliott fits of absorption spectra offer the possibility to determine both E B and E g . However, since excitonic effects are non-negligible even at room temperature, a careful and detailed analysis of the spectra is crucial for a correct interpretation. Therefore, an additional evaluation based on a so-called f-sum rule is applied to achieve an improved reliability of the results at higher temperatures. The obtained E B values of 20-24 meV for Cs-containing mixed perovskite compounds are below the ones of 24-32 meV and 36-41 meV for pure methylammonium lead iodide (MAPbI 3 ) and bromide (MAPbBr 3 ), respectively, and, thus, facilitate charge-carrier separation in photovoltaic applications. Furthermore, temperature-dependent (T = 5-300 K) studies of E g in (Cs,FA,MA)Pb(I,Br) 3 indicate a suppressed crystal phase transition by the absence of any phase-transition related signatures such as the well-known jump of about 100 meV in MAPbI 3 . We verify these results using temperature-dependent electroreflectance spectroscopy, which is a very reliable technique for the direct and non-destructive determination of optical resonances of the absorber layer in complete solar cells. Additionally, we confirm the suppression of the phase transition in Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 by temperature-dependent X-ray diffraction
- …
