Red Region Research Articles

Potent biological activity of newly fabricated silver nanoparticles coated by a carbon shell synthesized by electrical arc

Highly effective AgNPs@C was efficiently synthesized by electrical arc powered by single spark unit which was sufficient to ionize the dielectric media (deionized water) through applying strong electric field between the electrodes (silver and carbon). The AgNPs@C shell was characterized in terms of stability, morphology and phase structure. All characterizations showed that the prepared silver nanoparticles were spherical with average size reached 17 nm coated with carbon shell. The antibacterial effect of the synthesized nanoparticles was tested against Pseudomonas aeruginosa in comparison to Ceftazidime (commonly used antibiotic against P. aeruginosa infections). It was revealed that AgNPs@C shell has superior activity with inhibition zone diameter reached 15 mm and minimum inhibitory concentration reached 2 µg/mL. The observed activity was further confirmed by confocal microscope which showed an increased red region, representing the dead cells, correlated with the presence of AgNPs@C. Moreover, transmission electron microscope studies implied the possible AgNPs@C antibacterial mechanism of action was the nanoparticles adherence to the bacterial membrane causing cell lysis. The molecular studies against fimH (virulence adhesion gene), rmpA (mucoid factor encoding gene), and mrkA (biofilm forming gene) proved the inhibition of their genetic expression. The cytotoxic effect of the synthesized AgNPs@C showed CC50 reached 235.5 μg/mL against normal lung cells (L929 cell line).

Solvatochromic Behavior of Solid-State Nitrogen-Doped Carbon Nanoparticles: Initial Study

Carbon nanoparticles (CNPs) have garnered significant attention among researchers due to their cost-effectiveness and tunable properties, rendering them applicable in a wide array of fields, including biomedicine, optoelectronics, catalysis, and sensing. The solvatochromic effect denotes the phenomenon of a compound exhibiting a color change or a shift in its photoluminescence spectrum. In this study, we investigated the solvatochromic behavior of CNPs doped Nitrogen synthesized through the solid-state route using citric acid and urea, dissolved in solvents with varying polarity indices. Significant differences in emission were analyzed using a photoluminescence (PL) spectrometer. The results exhibit the emission shifting towards longer wavelengths (red region) as the solvent’s polarity index increased. This study of solvatochromic behavior in CNPs holds substantial significance for further research into their application as sensors.

Role of the CXCR4-Gnαq-Plcβ signaling pathway in the pathogenesis of collagen-induced arthritis in rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease in which immune cells and inflammatory cytokines are abnormally activated, leading to immunoregulatory dysfunction in the body and triggering systemic inflammatory responses. The interaction between CXC chemokine receptor 4 (CXCR4) and heterotrimeric G-protein α-subunit Gαq (Gnαq) activates phospholipase Cβ (PLCβ), which influences the expression of downstream effectors and participates widely in the onset and development of various diseases, thus suggesting the potential involvement of these molecules in RA pathogenesis. Therefore, the present study aimed to determine whether the CXCR4-Gnαq-PLCβ signaling pathway participates in the onset and development of RA. Using a collagen-induced arthritis (CIA) rat model, we found that compared with the control (healthy) rat group, CIA rats exhibited highly time-dependent arthritis, with the maximum arthritis score occurring in week 3. In contrast to the splenic and joint tissue of control rats, CIA rats showed obvious hyperplasia in the lymphoid white pulp and main germination centers of the spleen, narrowing of joint cavities, and inflammatory cellular infiltration on articular surfaces. The serum levels of expression of IL-1β, IL-4, IL-6, and TNF-α were significantly elevated (P < 0.05, P < 0.01). Core genes of the CXCR4-Gnαq-PLCβ pathway, namely CXCR4, Gnαq, PLCβ1, MMP1, and MMP3, also showed a significant increase in mRNA and protein expression levels (P < 0.05, P < 0.01). Proteins related to the CXCR4-Gnαq-PLCβ pathway were mainly localized to the red and white pulp regions in the spleen as well as in stromal, endothelial, and subdifferentiated synovial cells in the joints. These results indicated that CXCR4 is dependent on Gnαq for inducing the expression of PLCβ1 and stimulation of secretion of inflammatory cytokines by inflammatory cells. This consequently affects the expression of matrix metalloproteinases (MMPs), which serve as downstream effectors, thereby promoting RA pathogenesis. Our findings play an important role in elucidating the mechanisms of the onset and development of RA.

Assessing rainfall erosivity changes over China through a Bayesian averaged ensemble of high-resolution climate models

Spatiotemporal variation in rainfall erosivity resulting from changes in rainfall characteristics due to climate change has implications for soil erosion in developing countries. To promote soil and water conservation planning, it is essential to understand past and future changes in rainfall erosivity and their implications on a national scale. In this study, we present an approach that uses a Bayesian model averaging (BMA) method to merge multiple regional climate models (RCMs), thereby improving the reliability of climate-induced rainfall erosivity projections. Our multi-climate model and multi-emission scenario approach utilize five RCMs and two Representative Concentration Pathways (RCP4.5 and RCP8.5) scenarios for the baseline period (1986–2005) and future periods (2071–2090) to characterize the spatiotemporal projection of rainfall erosivity and assess variations in China. Our results indicate that the two models outperform other models in reproducing the spatial distribution and annual cycle of rainfall erosivity in China. Moreover, we found an increasing trend in the annual rainfall erosivity from the baseline climate up to the RCMs for all models, with an average change in erosivity of approximately 10.9% and 14.6% under RCP4.5 and RCP8.5, respectively. Our BMA results showed an increase in the absolute value of rainfall erosivity by 463.3 and 677.0 MJ·mm·hm−2·h−1, respectively, in the South China red soil region and the Southwest China karst region under the RCP8.5 scenario. This increase indicates that climate warming will significantly enhance the potential erosion capacity of rainfall in these regions. Additionally, our study revealed that the Southwest China karst region and the Northwest China Loess Plateau region are more sensitive to radiation forcing. To mitigate the risk of soil erosion caused by climate change, it is necessary to consider changes in rainfall erosivity, local soil conditions, vegetation coverage, and other factors in different regions and take appropriate soil and water conservation measures.

Modifying Fluorescent Protein Chromophore to Detect Protamine and Application in Real Serum Samples

AbstractAs effective methods to accurately and rapidly detect protamine remains a major challenge, here we present a fluorescent protein chromophore‐based probe (IDL‐FP) utilizing twisted‐intramolecular charge transfer (TICT) to detect protamine. The introduction of an electron‐donor group 4‐dimethylaminobenzaldehyde extends the emission wavelength of IDL‐FP to the red region. The deprotection of t‐butyloxy carbonyl groups can then generate an electronegative carboxyl group, which promotes the binding to protamine via electrostatic attraction. Thus, IDL‐FP is sensitive and specific towards protamine and can serve as a highly selective detector for protamine with a detection limit as low as 8.87 ng/mL. As IDL‐FP exhibited good stability in physiological pH environment, we successfully apply IDL‐FP to detect spiked‐in protamine in human serum. In summary, probe IDL‐FP is a promising tool for the quantitative determination of protamine.

Blue-white electroluminescence of diamond/WS2 quantum dot composite films

Two kinds of diamond films with completely different morphologies were prepared on N-type heavily doped silicon wafers by microwave plasma chemical vapor deposition (MPCVD) method, namely, micron-scale large grain polycrystalline diamond film dominated by (220) crystal plane (220DF) and nano-scale small grain polycrystalline diamond film dominated by (111) crystal plane (111DF). And WS2 quantum dot powder was obtained by aqueous liquid phase ultrasonic method. Then, the 111DF/WS2 quantum dot composite structure film (111DWSF) and 220DF/WS2 quantum dot composite structure film (220DWSF) were prepared by applying WS2 quantum dot powder uniformly on diamond film substrate. The results of electroluminescence (EL) detection show that the 220DWSF device emits visible blue light, and the main peak of EL spectrum is located at 443 nm in the blue region. The 111DWSF device emits white light, and the corresponding EL spectra show strong emission peaks in the blue region (454 nm), green region (536 nm) and red region (632 nm) respectively, meanwhile, the luminous intensity of 111DWSF device is much higher than that of 220DWSF device. In addition, it is also found that the 220DWSF EL device does not show obvious rectification characteristics, while the 111DWSF EL device has obvious rectification characteristics. After FN fitting of the IV characteristic curve of 111DWSF EL device, the tunneling characteristics of electrons are found in the region of high electric field intensity.

Occurrence, distribution, and composition of black sand along the Red Sea, Egypt

Black sand along the Red Sea is often composed of volcanic minerals and heavy minerals. The Red Sea region is known for its unique geological features, and black sand beaches can be found in various areas along its shores. The study presents a comprehensive semi-quantitative chemical analysis of black sand samples collected from various locations along the red sea, revealing significant variations in their elemental compositions. The main oxides were identified in each sample, determined through X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses, indicate diverse mineralogical compositions. The spatial distribution of minerals at each site is depicted through mapping. Additionally, Fourier-transform infrared (FTIR) spectra offer information on the functional groups present in the samples, revealing the existence of hydroxyl groups, aliphatic compounds, and adsorbed water molecules. For Qusier-Elsharm Alqbly, Safaga, Marsa Alam, Gabal Alrosass, Hurghada Titanic, Hurghada Elahiaa, Gemsa, and Ras Elbehar samples, the results highlight the presence of various minerals, such as Quartz, Calcite, Titanium Dioxide, Magnetite, Hematite, Aluminum Oxide, Zirconium Dioxide, Chromium (III) Oxide, and others, providing insights into the geological characteristics of each location. The differences in mineral content among the examined sites are linked to the geological and mineralogical makeup of the source rocks upstream and midstream in the basins that discharge into the surveyed regions. So, variations in black sand concentrations among different locations offer insights into the geological and mineralogical diversity of the studied areas along the Red Sea coast. This study addresses the existing knowledge gap by focusing on the preliminary exploration and description of the occurrence, distribution, and composition of black sand along the Red Sea in Egypt. whereas the results provide valuable insights into the geological diversity of black sand deposits in the surveyed areas, underscoring the need for additional research and interpretation of these variations. Therefore, the in-depth examination of mineralogical composition and crystal structures establishes a foundation for future investigations in the field of geology and earth sciences.

Preparation and photoluminescence study of rare-earth-free red emitting La3Ga5SiO14:Mn4+ phosphors

Given the growing interest in eco-friendly lighting solutions, the use of high-quality phosphors has become integral to the advancement of all-solid white light-emitting diodes (WLEDs). One novel phosphor, La3Ga5SiO[Formula: see text]:Mn[Formula: see text] (LGS), has been successfully synthesized via a high-temperature solid-state reaction. The crystal structure of LGS is classified as belonging to the trigonal phase, with a space group P321. The excitation spectrum exhibits a wide peak within the wavelength range of 280–440 nm. It emits a highly intense red light, with a peak emission occurring at 715 nm within the spectral range of 670–740 nm is attributed to the transition of Mn[Formula: see text] from 4A2g to 4T2g. LGS:Mn[Formula: see text] demonstrates a favorable quantum efficiency of 16% when doped with a concentration of 0.25 mol% Mn. The decay curve of LGS:Mn[Formula: see text] exhibits a pattern of decreasing lifetime as the dopant concentration increases. Additionally, the LGS:Mn[Formula: see text] products demonstrate a CIE chromaticity of (0.688, 0.2644), which is located within the deep red light region. All the aforementioned findings support the potential application of LGS:Mn[Formula: see text] specimens in WLEDs, thereby contributing to the progress of environmentally friendly and energy-efficient lighting.

Numerical Analysis of the ZnGeN2 Layer Effect on InGaN/GaN Multiple Quantum Well Light-Emitting Diodes

This paper discusses the effect of a ZnGeN2 layer inserted into the wells of Type-I InGaN/GaN QWs LEDs on the electrical and optical properties by using the Silvaco TCAD Simulator. First, the new structure is compared to the standard type-I LED based on InGaN. We found that using ZnGeN2 layer in the In0.2Ga0.8N-QWs LED leads to wavelength extending from the blue to the red region. Next, we highlighted the effect of quantum well number and In-molar fraction in the wells of InxGa1-xN/ZnGeN2 type-II LEDs. As a result, increasing the number of wells from two to six QWs creates an extension of spontaneous emissions while keeping a low concentration of indium in the wells (x = 0.16) and improving the electrical and optical properties, as we found an improvement in light output power of 10.7% at 40Acm-2.

Impact of π-spacer on dye-sensitized solar cells and non-linear optical performance: Styryl vs imine vs azo

Julolidine-based dyes, having a benzoic acid anchoring group, conjugated through different π-bridges (styryl, imine, and azo) have been investigated. It is discovered that the charge transfer (CT) characteristics of the dye system are changed as the π-bridges become less symmetrical. According to TD-DFT studies, the vertical absorption maximum shifts to the red region when the “N” atom is added to the styryl backbone. Computed photovoltaic characteristics, however, indicate that these dyes perform poorly when the “N” atom is added to the styryl backbone. Studies on dye@TiO2 clusters showa possible bonding between these dyes and TiO2, which would cause dye@TiO2 cluster absorption to shift red. Conversely, computed results of linear and non-linear optical (NLO) properties exhibit opposite patterns to those observed in dye-sensitized solar cell (DSSC) performance.Julolidine-based dyes with imine and azo linkers combined with benzoic acid were created and evaluated as DSSC sensitizers to determine their practical application. In agreement with DFT findings, experimental absorption in dimethylformamide (DMF) and cyclic voltammetry (CV) study verified the essential need for HOMO and LUMO energy levels. High thermal stability is indicated by the thermogravimetric analysis (TGA) results, which supports practical applications in DSSCs and non-linear optics (NLO). The efficiency patterns of the fabricated DSSC cells were similar, with JNNC showing the lowest efficiency (0.07 ± 0.02) and JCNC-OH demonstrating the highest (1.94 ± 0.02).

"Iron Ion Relative Weathering Index": A New Index for Identifying the Weathering Degree in Red Sandstone.

The red bed region in west central and southern China is affected by hot and humid climate, where sandstone is intensely weathered. The weathered hazardous rocks seriously threaten the road and slope, making it challenging to protect the Danxia red bed. After considering the red sandstone's material composition and the local area's main weathering effects. We noticed that iron ions in red sandstone are susceptible to weathering, which leads to changes in the valence and content of iron ions. This study attempts to establish a new chemical weathering index called the "iron ion relative weathering index" (IRWI) to classify the weathering degree of red sandstone. This paper mainly explores the changes of physical characteristics (mineral composition, physical indicator, microstructure, and pore structure) from the surface to the interior of red sandstone in the actual environment and their correlation with IRWI. The study on the correlation between the physical indicators such as longitudinal wave velocity, resistivity, density, water absorption, and IRWI reveals that they have the same trends and are closely related to the weathering degree. The shallow weathering zone of Chishui red sandstone is divided into strong, medium, and slight weathering zones. Microscopically, the cementation and pore distribution of the red sandstone are consistent with the characteristics of the weathering zone. Therefore, IRWI not only is a reliable chemical quantitative method in indicating the weathering of red sandstone but also takes into account the controlling role of iron in the color development of red beds, which provides a new research idea for the quantitative identification of weathering degree and color mechanism of red sandstone.

Responses of deep soil moisture to direct rainfall and groundwater in the red soil critical zone: A four-stage pattern

Deep soil moisture (DSM) plays a critical role in vadose zone hydrological processes. However, the recharge processes and their underlying mechanisms remain unclear due to the scarcity of comprehensive deep hydrological data, especially in regions characterized by active interactions between surface and subsurface hydrological processes. To address this knowledge gap, we performed an event-based study using a four-year hydrological monitoring dataset, encompassing rainfall, profile soil moisture, and groundwater along a hillslope at the Red Soil Critical Zone Observatory (CZO) in China. A total of 226 rainfall events were classified into four distinct types (I-IV) using a k-means clustering algorithm. The changes in DSM and groundwater table (GWT) were dependent on the rainfall type. The GWT (0.57–0.97) played a greater role in contributing to the DSM than the direct rainfall (0.48–0.64) based on a structural equation model, which was more pronounced from upper slope to foot slope. DSM recharge pattern can be described by a four-stage conceptual model, as indicated by the relationship between DSM and GWT: a slow and linear increase (stage 1), a small plateau (stage 2), a rapid linear rise (stage 3), and finally a great plateau (stage 4). DSM at the small and great plateau were closely related with the field capacity and saturation, respectively. Rainfall type, vadose zone features, and soil physical properties jointly shaped DSM recharge patterns. These findings can offer valuable insights into understanding the deep hydrological processes of the red soil region as well as regions with similar hydroclimatic conditions.

Innovative approach for predicting daily reference evapotranspiration using improved shallow and deep learning models in a coastal region: A comparative study

Accurate and reliable estimation of Reference Evapotranspiration (ETo) is crucial for water resources management, hydrological processes, and agricultural production. The FAO-56 Penman-Monteith (FAO-56PM) approach is recommended as the standard model for ETo estimation; nevertheless, the absence of comprehensive meteorological variables at many global locations frequently restricts its implementation. This study compares shallow learning (SL) and deep learning (DL) models for estimating daily ETo against the FAO-56PM approach based on various statistic metrics and graphic tool over a coastal Red Sea region, Sudan. A novel approach of the SL model, the Catboost Regressor (CBR) and three DL models: 1D-Convolutional Neural Networks (1D-CNN), Long Short-Term Memory (LSTM), and Gated Recurrent Unit (GRU) were adopted and coupled with a semi-supervised pseudo-labeling (PL) technique. Six scenarios were developed regarding different input combinations of meteorological variables such as air temperature (Tmin, Tmax, and Tmean), wind speed (U2), relative humidity (RH), sunshine hours duration (SSH), net radiation (Rn), and saturation vapor pressure deficit (es-ea). The results showed that the PL technique reduced the systematic error of SL and DL models during training for all the scenarios. The input combination of Tmin, Tmax, Tmean, and RH reflected higher performance than other combinations for all employed models. The CBR-PL model demonstrated good generalization abilities to predict daily ETo and was the overall superior model in the testing phase according to prediction accuracy, stability analysis, and less computation cost compared to DL models. Thus, the relatively simple CBR-PL model is highly recommended as a promising tool for predicting daily ETo in coastal regions worldwide which have limited climate data.

Explaining Color Change in Gem-Quality Andradite Garnet

The homomorphic substitution of the garnet group is common in nature. Two rare color-changing andradite garnets are studied in this paper. One color changes from yellowish-green in the presence of daylight to maroon under incandescent light; the other color changes from brownish yellow to brownish red. In this study, conventional gemological instruments, infrared (IR) spectroscopy, ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy, Raman spectroscopy, and electron probe microanalysis (EPMA) were used to explore the gemology and coloration mechanisms of color-changing garnets. Experiments revealed that the color-changing gemstones in the study are andradite garnets. There are two transmission windows in the UV–Vis spectrum: the red region (above 650 nm) and the green region (centered at 525 nm). The chemical compositional analysis indicates that the samples are very low in Cr (&lt;1 ppm) and high in Fe2+ (from 2.31 wt.% to 4.66 wt.%). The combined spectra and chemical compositional analysis show that Fe2+ is the main cause of the color change. Based on the IR spectrum (complex water peaks), UV–Vis–NIR spectrum (similar to that of Namibian andradite garnet), and chemical compositional analysis (low Cr content), it is concluded that color-changing andradite may be related to skarn rock genesis.

Applying Geostatistics to Understand Seismic Activity Patterns in the Northern Red Sea Boundary Zone

A comprehensive geostatistical analysis was conducted on a dataset comprising 24,321 seismic events in the Red Sea region, spanning from 1997 to 2020. This analysis involved the creation of a new seismic activity database, incorporating data from both Egyptian and Saudi Seismic Networks. This enriched database provided a robust foundation for a detailed examination of the seismic patterns and activities in the region. Utilizing geographic information systems and various spatial analytic methods, it identifies seismic patterns and tectonic influences. The findings reveal significant seismic clustering along the Central Red Sea axis, indicative of active rifting between the Nubian and Arabian plates. The study demonstrates spatial autocorrelation in seismic activities, with high-high clusters marking zones of elevated seismicity. Kernel Density Estimator analyses highlight concentrated seismic activity in the Gulfs of Aqaba and Suez. Higher magnitude events are shown to localize in areas of greater tectonic stress, aligning with known geological features. This research provides critical insights into the seismic dynamics of the Red Sea, showcasing the effectiveness of geostatistical techniques in analyzing seismic data in tectonically active regions.

The Carbon Storage of Reforestation Plantings on Degraded Lands of the Red Soil Region, Jiangxi Province, China

To assess the effects of reforestation on ecosystem carbon storage, a long-term Forest Restoration Experimental Project (FREP) was established in 1991 on southern degraded red soil in Taihe County, Jiangxi Province, China. In this study, we selected five types of plantations: Schima superba plantation (SS), Liquidambar formosana plantation (LF), Pinus massoniana plantation (PM), Pinus elliottii plantation (PE), and P. elliottii and broadleaf mixed plantation (MEB). The unforested land was used as an experimental control check (CK). We aimed to assess the changes in carbon storage in plantations and the factors affecting them. Thirty years after reforestation, the ecosystem carbon storage of the five types of plantations was significantly higher than that of the control site, and there were also significant differences in the ecosystem carbon storage between the different plantation types (p &lt; 0.05). The ecosystem carbon storage of SS, MEB, LF, PM, and PE were 211.71 Mg ha−1, 199.02 Mg ha−1, 160.96 Mg ha−1, 155.01 Mg ha−1, and 142.88 Mg ha−1, respectively. Compared to the CK, these values were increased by 436.8%, 404.6%, 308.1%, 293.1%, and 262.3%, respectively. The ecosystem carbon storage was significantly positively correlated with soil porosity, total nitrogen (TN), and stand density, and was significantly negatively correlated with pH, Pielou’s evenness index (PEI), and the Shannon–Weiner diversity index (SWDI). The soil water content (SWC), bulk density (BD), SWDI, and stand density can be used as indicators of the impact of reforestation plantings on ecosystem carbon storage. The research results has shown that reforestation plantings significantly increase ecosystem carbon storage, and that afforestation should be encouraged on degraded land.

Luminescence Properties of Al2O3:Ti in the Blue and Red Regions: A Combined Theoretical and Experimental Study.

Using jointly experimental results and first-principles calculations, we unambiguously assign the underlying mechanisms behind two commonly observed luminescence bands for the Al2O3 material. Indeed, we show that the red band is associated with a Ti3+ d-d transition as expected, while the blue band is the combination of the Ti3+ + O- → Ti4+ + O2- and VO•+e- → VO× de-excitation processes. Thanks to our recent developments, which take into account the vibrational contributions to the electronic transitions in solids, we were able to simulate the luminescence spectra for the different signatures. The excellent agreement with the experiment demonstrates that it should be possible to predict the color of the material with a CIE chromaticity diagram. We also anticipated the luminescence signature of Al2O3:Ti,Ca and Al2O3:Ti,Be that were confirmed by experiment.

Abstract TMP4: Computational Fluid Dynamics Analysis Offers Novel Preoperative Insights for Unruptured Cerebral Aneurysms - Predicting Aneurysm Wall Thinning and Thickening -

Objective: The preoperative identification of thin-walled regions (TIWRs) and thick-walled regions (TKWRs) in cerebral aneurysms can contribute to enhancing surgical safety. Our recent computational fluid dynamics (CFD) analysis of cerebral aneurysms has demonstrated that the wall shear stress vector cycle variation (WSSVV) and the oscillatory shear index (OSI) can potentially predict TIWRs and TKWRs. This study aims to validate the accuracy of using WSSVV and the OSI to identify these areas and to report on their effectiveness in actual surgeries. Methods: Our cohort comprised 42 patients who underwent cerebral aneurysm clipping surgery at our hospital from January 2019 to September 2022. CFD analysis was performed using Hemoscope. We defined suspected TIWRs as blue regions and suspected TKWRs as red regions on both color maps. We evaluated the positive predictive value (PPV) by comparing these preoperative suspected areas with actual thin and thick areas determined intraoperatively under surgical microscopic observation. Results: Of the 42 patients, 15 were male and 27 were female. The average age was 63 years, and the average aneurysm size was 5.9 mm. The location of the aneurysms was the middle cerebral artery in 18 cases, the internal carotid artery in 15 cases, the anterior communicating artery in 8 cases, and the basilar artery in 1 case. WSSVV yielded a PPV of 83% for TIWRs and a PPV of 78% for TKWRs. In comparison, the OSI demonstrated a PPV of 77% for TIWRs and 76% for TKWRs. Spearman's rank correlation analysis revealed a strong correlation between WSSVV and the OSI; the correlation coefficient was 0.883 (p-value &lt; 0.001). Conclusions: CFD analysis of unruptured cerebral aneurysms could be used to predict TIWRs and TKWRs using both WSSVV and the OSI with an accuracy of approximately 80%. The preoperative evaluation of the wall condition using CFD analysis appears to be highly reliable and is likely to contribute to the safety of cerebral aneurysm surgery.

Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C∧N∧C) Pincer Ligand─A Comparative Study.

We here report the synthesis of the homoleptic iron(II) N-heterocyclic carbene (NHC) complex [Fe(miHpbmi)2](PF6)4 (miHpbmi = 4-((3-methyl-1H-imidazolium-1-yl)pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) and its electrochemical and photophysical properties. The introduction of the π-electron-withdrawing 3-methyl-1H-imidazol-3-ium-1-yl group into the NHC ligand framework resulted in stabilization of the metal-to-ligand charge transfer (MLCT) state and destabilization of the metal-centered (MC) states. This resulted in an improved excited-state lifetime of 16 ps compared to the 9 ps for the unsubstituted parent compound [Fe(pbmi)2](PF6)2 (pbmi = (pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) as well as a stronger MLCT absorption band extending more toward the red spectral region. However, compared to the carboxylic acid derivative [Fe(cpbmi)2](PF6)2 (cpbmi = 1,1'-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi)2](PF6)4 is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi)2](PF6)4 a promising pH-insensitive analogue of [Fe(cpbmi)2](PF6)2. Finally, the excited-state dynamics of the title compound [Fe(miHpbmi)2](PF6)4 was investigated in solvents with different viscosities, however, showing very little dependency of the depopulation of the excited states on the properties of the solvent used.

Liquid benzothiadiazole-based organic luminophores emitting light from the blue to red spectral region: synthesis, properties, and application in liquid scintillators

Liquid organic luminophores (LOLs) have been actively investigated as a new generation of functional materials in various fields of organic optoelectronics and photonics. However, many issues, including the structure–properties relationships and the development of LOLs emitting light in the red spectral range, remain poorly investigated. Here we report on the synthesis and investigation of a series of novel conjugated luminescent molecules consisting of a central 2,1,3-benzothiadiazole electron-withdrawing unit and lateral thiophene or phenylene electron-donating fragments with terminal trialkylsilyl units as solubilizing groups (SGs). Thermal and thermo-oxidative stability, phase behavior, structural properties, rheology, and optical and electrochemical properties of the obtained luminophores were studied and compared to their counterparts without SGs or with ineffective SGs for liquefaction. The target compounds are luminescent liquids with low glass transition temperatures (up to −65 °C) and viscosities (up to 1.7 Pa s) or liquid crystal materials emitting light in almost the entire visible spectral range with high photoluminescence quantum yield (PLQY) both in solutions (up to 97 %) and films (up to 87 %). For the first time, the application of LOLs as a new generation of organic liquid scintillators was demonstrated, achieving a light yield up to 1.7 times higher than that of a standard liquid scintillator.