White Regions Research Articles

Comparative studies on CIELab, thermal and optical characteristics of Dysprosium (Dy3+) incorporated phospho-tellurite glasses for white light generation

Concentration dependence of Dy3+ activated strontium lead phospho-tellurite glass series have been synthesized by melt quenching process. To explore the structural, thermal and optical traits of the present glasses we have investigated XRD, FTIR, DTA, UV–Vis–NIR absorption, optical band gap, excitation band, luminescence emission, decay lifetime and CIE chromaticity diagram, and analysed the Judd-Ofelt intensity parameters Ωλ (λ = 2,4,6) and various radiative parameters in detail. The photoluminescence spectra exhibit highly intense blue and yellow emissions at around 483 and 573 nm. The better values of yellow/blue intensity ratio and branching ratio (βexp) suggest that the proposed glass series are efficient candidates for visible laser media. Emission quenching effect has been observed beyond 1 mol% Dy3+ doping concentration. The luminescence lifetime of the 4F9/2 excited level declines with increasing Dy3+ doping level. The experimental lifetime and quantum efficiency of 1 mol% Dy3+ activated glass are acquired to be 0.75 ms and 81%, respectively. The appearance of chromaticity coordinates as well as CIELab coordinates in the white region highlights that the present glass system could be most promising for white light generation.

Reduced cortical cholinergic innervation correlates with cognitive decline in mild cognitive impairment

AbstractBackgroundDysfunction of the cholinergic basal forebrain (BF) neurotransmitter system, including cholinergic axon denervation of the cortex, plays an important role in cognitive decline and dementia. The association of cortical cholinergic denervation with diverse cognitive profiles in dementia, particularly at early stages, has not yet been fully explored. We assessed the relationship of cholinergic denervation in the cortex measured using 18F‐fluoroethoxybenzovesamicol (FEOBV) with cognitive decline at an early stage of dementia.MethodParticipants (8 with mild cognitive impairment (MCI) and 10 cognitively unimpaired (CU) controls, aged 60‐86, 55.6% female, MMSE = 28.7±1.5) underwent neuropsychological assessment and FEOBV PET imaging. The neuropsychological battery of tests included measures of memory, executive function, attention and language. Domain‐specific composite scores were calculated by averaging z‐scores of the related tests or subtasks within a domain. FEOBV images were co‐registered to the concurrent structural MRI and normalised to the supratentorial white matter reference region resulting in a standardized uptake value ratio (SUVR). Voxel‐wise analysis was performed on normalised FEOBV images to investigate associations with clinical diagnosis and domain‐specific cognitive performance. Voxel‐based morphometry was also performed to rule out differences in brain morphology. All analyses were corrected for age, sex and total intracranial volume and adjusted for multiple comparisons.ResultThe MCI group showed significantly lower global FEOBV SUVR in the cortex although only a focal cluster of reductions near the right middle temporal gyrus was found in the voxel‐wise comparisons. When associations with cognitive performance profiles were assessed in the full cohort, regional positive correlations were found between FEOBV SUVR and cognitive scores across different domains (Figure 1), although these did not include memory. For executive functioning, widespread correlation patterns were observed across both cortical and subcortical regions. Moreover, overlapping profiles were identified for all three cognitive domains of executive function, attention and language, which covered the anterior cingulate gyrus, olfactory cortex, calcarine cortex, middle temporal gyrus and caudate nucleus.ConclusionWe have demonstrated that the topographic profile of FEOBV retention correlated with reduced cognitive performance in different domains, suggesting that reduced cortical cholinergic terminal integrity is an important pathological feature of cognitive decline.

Impact of disease stage and reference region selection on longitudinal tau 18F‐MK6240 PET in Alzheimer’s disease

AbstractBackgroundTau PET imaging enables prospective longitudinal observation of the rate and location of tau accumulation in Alzheimer’s disease (AD). 18F‐MK6240 is a newer, high affinity tracer for the paired helical filaments of tau in AD. It is widely used in clinical trials, despite sparse longitudinal natural history data. We aimed to evaluate the impact of two reference regions on the magnitude and effect size of regional change.MethodOne hundred and fifty‐eight participants: 83 Aβ‐ cognitively unimpaired (CU), 37 Aβ+ CU, 19 Aβ+ MCI, 19 Aβ+ AD had annual 18F‐MK6240 PET imaging for a mean of 1.6 years. Standardized uptake value ratios (SUVR) were generated for three in‐house composite ROI: mesial temporal (Me), temporoparietal (Te), and rest of neocortex (R), and a Free‐Surfer derived meta‐temporal (MT) ROI. Two reference regions were examined: cerebellar cortex (SUVRcb) and eroded subcortical white matter (SUVRwm).ResultFigure 1 shows the annual rate of tau SUVR change in composite ROI. In Aβ+ CU, tau accumulation was greatest in Me (2.8‐3.2%/ year) (vs Aβ‐ CU, Cohen’s d = 0.30 SUVRcb, 0.24 SUVRwm) and MT (3.2‐3.6%/year) (vs Aβ‐ CU, d = 0.36 SUVRcb, 0.31 SUVRwm). In Aβ+ MCI, tau accumulation was greatest in Te (2.3‐3.7%/year) (vs Aβ‐ CU, d = 0.34 SUVRcb, 0.41 SUVRwm). In Aβ+ AD, greatest increase was in Te and R, with a decrease in Me. In Aβ+ AD, SUVRcb showed marginally greater increase in these regions (e.g. 3.8%/year compared to 2.68%/year SUVRwm in R) (vs Aβ‐ CU, d = 0.60 SUVRcb, 0.27 SUVRwm). In the young Aβ+ AD dementia group, spill‐over from adjacent high cortical binding or an increase in white matter binding elevates signal in the reference region.ConclusionThe rate of tau accumulation varies according to brain region and baseline tau. Change is greatest in the MTL in preclinical AD, in the MTL and lateral temporal cortex in MCI, and Braak V‐VI regions in AD dementia. The PET measured change is greater and less variable using an eroded white matter reference region, except in AD dementia, where spill‐over from adjacent high cortical binding or increase in white matter binding elevates the reference region.

An Investigation of the Relationship Between Carotid Artery Stenosis and White Matter Hyperintensities.

Introduction White matter hyperintensities (WMHs) are frequently detected on magnetic resonance imaging (MRI) with age. Although the etiology of WMH has not been fully explained, it was reported to be associated with internal carotid artery (ICA) stenosis as well as small vessel diseases. The number and volume of these lesions might increase in cases of internal carotid artery (ICA) stenosis. The present study aimed to calculate the localization and volumes of white matter lesions in the VolBrain Program and investigate the relationship between age and sex in patients with symptomatic and asymptomatic internal carotid artery stenosis. Methods MRI scans of patients with carotid stenosis with T1-weighted and fluid-attenuated inversion recovery (FLAIR) sequences were performed retrospectively for the present study, which had a retrospective design. The patients were divided into two groups (<70% and ≥70%) because endovascular intervention was considered in patients with asymptomatic stenosis over 70%. Digital subtraction angiography was used to detect carotid artery stenosis. They were also divided into four groups.According to laterality and degree of stenosis, ICA stenosis was separated as those with <70% stenosis on both sides (group 1), right side ICA <70%, left side ≥70% stenosis (group 2), right side ICA ≥70%, left side <70% stenosis (group 3), and ≥70% stenosis on both sides (group 4). A total of 102 patient images were selected that met the inclusion criteria. The measurements of white matter lesion volumes were made using the LesionBrain application in the VolBrain Program. Results The MRI of 82 patients (mean age: 65.55 ± 9.28 years), 28 females and 54 males, were used in the present study. According to LesionBrain Analysis, the total WMH volume was seen in the first and third groups at most. When analyzed in regional terms, stenosis was mostly detected in the first and third groups in the periventricular region. WMH volume was less in all areas in group 4. When examined according to the number of lesions, the most lesions were detected in the third group in the juxtacortical region. When the difference between the groups was examined, a significant difference was detected only in the volume change in the deep white region (p=0.011). No significant differences were found between WMH volumes and age and gender (p>0.05). Conclusion Stenosis of the external internal carotid artery might cause hypoperfusion and silent embolization in the brain. As a result, as well as pathological conditions in cortical areas, ischemic areas in the white matter might also cause cognitive disorders.

Hybrid of Conjugated Polymers with Incorporation of Metal Oxide Nanocomposites for Improving Optoelectronic Properties

Herein, the incorporation of TiO2 nanoparticles (NPs), SiO2 NPs, and their nanocomposite (STNC) to enhance the optoelectronic properties of the hybrid of poly[9,9′‐di‐n‐octylfluorenyl‐2,7‐diyl] (F8), poly[2‐methoxy‐5(2‐ethylhexyl)‐1,4‐phenylenevinylene)] (MEH‐PPV), and poly[2‐methoxy‐5‐(3,7‐dimethyl‐octyloxy)‐1,4‐phenylenevinylene]‐end capped with dimethylphenyl (MDMO–PPV–DMP) are revealed. The tune of the donor (F8) conjugated length can be detected from the red shift in absorption spectra when TiO2 NPs and SiO2 NPs are added, as well as an increase in emission intensity of the donor. The addition of acceptors (MEH–PPV or MDMO–PPV–DMP) to the donor results in a new absorption peak at 510 nm, which increases when TiO2 NPs and SiO2 NPs or STNC are incorporated into the ternary hybrid. The incorporation of STNC into F8 is anticipated to reduce the donor energy bandgap and improve the energy transfer from F8 to both acceptors. Moreover, Förster resonance energy transfer (FRET) is improved in the ternary hybrid, as evidenced by enhanced emission spectra of the donor and both acceptors, increased broadness of photoluminescence excitation spectra, and shifting blue color toward white region. The ternary hybrid with STNC‐based organic light‐emitting diode shows superior current and turn‐on voltage compared to other devices, which is likely due to its superior FRET.

A novel orange-red Ba3MgTa2O9:Eu3+ phosphor synthesis and luminescence properties in WLEDs

A new orange-red phosphor Ba3MgTa2O9:xEu3+ (0.05 ≤ x ≤ 0.60) was successfully prepared through the high-temperature solid-state reaction. A study of its structure, morphology, photoluminescence and fluorescence lifetime was conducted. By exposing the phosphor to near-ultraviolet (n-UV) light, orange-red light is generated as a result of the 7F0→5D1 magnetic dipole transition. The emission intensity is maximal at a doping concentration of x = 0.4, and concentration quenching occurs at higher concentrations. At 423 K, Ba3MgTa2O9:0.4Eu3+ phosphor luminescence intensity remained at 71% in reference to that at 303 K, showing good thermal stability. The CIE coordinates of the phosphor with the optimal doping concentration at room temperature are located at (0.6008, 0.3942) with a color purity of 98.27%. A high color rendering index is achieved by the prepared WLEDs, with Ra = 93.8 and CCT = 5671 K, which are located in the white light region of CIE with the coordinates of (0.3286, 0.3487). It is shown that the prepared Ba3MgTa2O9:Eu3+ phosphor is a potential orange-red phosphor material for WLEDs.

The Concept of Rwa Bhineda within the Balinese Hindu Society

Humans possess intelligence and consciousness to interact with their surrounding environment. This cognitive ability allows humans to contemplate, communicate, and participate in activities with others. The dynamic interplay of opposing forces, evident in the realms of positive and negative, joy and sorrow, is intricately woven into the fabric of Hindu thought. The concept of Rwa Bhineda extends metaphorically to encompass the entire spectrum of human experience, symbolizing the harmonious coexistence of contrasting elements. The Black and White characteristic regions within Rwa Bhineda, though seemingly contradictory, are inherently connected, mutually sustaining and weakening one another. This duality is not a source of conflict but rather a foundation for harmony, development, and progress. Furthermore, the application of Rwa Bhineda in Balinese local wisdom provides practical solutions to global challenges, emphasizing the importance of balance and harmonious coexistence amid differences. The Balinese cultural philosophy, encapsulated in concepts like Tri hita karana and Rwa Bhinedha, serves as a foundation for tolerance and diversity within Hindu religious practices. The celebration of Purnama and Tilem in the Balinese Wariga system symbolizes this concept, serving as reminders of life's inherent dualities and the potential for harmony through their complementary nature. Thus, the profound wisdom embedded in Rwa Bhineda offers a valuable perspective on navigating the complexities of human existence with grace and understanding.

Clinical Significance of Diffusion Tensor Imaging in Metachromatic Leukodystrophy.

Metachromatic leukodystrophy (MLD) is a lysosomal enzyme deficiency disorder leading to progressive demyelination and, consecutively, to cognitive and motor decline. Brain magnetic resonance imaging (MRI) can detect affected white matter as T2 hyperintense areas but cannot quantify the gradual microstructural process of demyelination more accurately. Our study aimed to investigate the value of routine MR diffusion tensor imaging in assessing disease progression. MR diffusion parameters (apparent diffusion coefficient [ADC] and fractional anisotropy [FA]) were in the frontal white matter, central region (CR), and posterior limb of the internal capsule in 111 MR datasets from a natural history study of 83 patients (age: 0.5-39.9 years; 35 late-infantile, 45 juvenile, 3 adult, with clinical diffusion sequences of different scanner manufacturers) as well as 120 controls. Results were correlated with clinical parameters reflecting motor and cognitive function. ADC values increase and FA values decrease depending on disease stage/severity. They show region-specific correlations with clinical parameters of motor and cognitive symptoms, respectively. Higher ADC levels in CR at diagnosis predicted a disease course with more rapid motor deterioration in juvenile MLD patients. In highly organized tissues such as the corticospinal tract, in particular, diffusion MR parameters were highly sensitive to MLD-associated changes and did not correlate with the visual quantification of T2 hyperintensities. Our results show that diffusion MRI can deliver valuable, robust, clinically meaningful, and easily obtainable/accessible/available parameters in the assessment of prognosis and progression of MLD. Therefore, it provides additional quantifiable information to established methods such as T2 hyperintensity.

Microbiota-mediated shaping of mouse spleen structure and immune function characterized by scRNA-seq and Stereo-seq

Gut microbes exhibit complex interactions with their hosts and shape an organism's immune system throughout its lifespan. As the largest secondary lymphoid organ, the spleen has a wide range of immunological functions. To explore the role of microbiota in regulating and shaping the spleen, we employ scRNA-seq and Stereo-seq technologies based on germ-free (GF) mice to detect differences in tissue size, anatomical structure, cell types, functions, and spatial molecular characteristics. We identify 18 cell types, 9 subtypes of T cells, and 7 subtypes of B cells. Gene differential expression analysis reveals that the absence of microorganisms results in alterations in erythropoiesis within the red pulp region and congenital immune deficiency in the white pulp region. Stereo-seq results demonstrate a clear hierarchy of immune cells in the spleen, including marginal zone (MZ) macrophages, MZ B cells, follicular B cells and T cells, distributed in a well-defined pattern from outside to inside. However, this hierarchical structure is disturbed in GF mice. Ccr7 and Cxcl13 chemokines are specifically expressed in the spatial locations of T cells and B cells, respectively. We speculate that the microbiota may mediate the structural composition or partitioning of spleen immune cells by modulating the expression levels of chemokines.

Characterization of Neuro-Immune Communication in the White Pulp Region of the Spleen

Abstract Norepinephrine (NE) is a ubiquitous neurotransmitter that facilitates cellular communication in the sympathetic nervous system. Recent advancements have shown sympathetic neurons innervate secondary immune organs, such as the spleen, to control immune physiology. Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique that varies an applied potential at a very fast scan rate with micro-electrodes to detect neurotransmitters with high temporal and spatial resolution. FSCV can be used to detect the sub-second release of NE in an ex vivomurine slice model to study the mechanisms related to neuro-immune communication. Our lab is the first to characterize and quantify this spontaneous transient signaling of catecholamines in the white pulp region of the murine spleen with FSCV. The average concentration of catecholamines released is 581 ± 20 nM, with an average inter-event time of 23.4 ± 0.7 s and a duration of 6.6 ± 0.1 s. Norepinephrine transporter (NET) is known to transport NE back into cells after endogenous release. We blocked NET with the inhibitor nomifensine to provide further evidence of NE release and study the mechanisms involved in NE uptake. To study the mechanisms of NE release in the spleen, we blocked α2-adrenoceptor, a known autoreceptor only found on neurons. Yohimbine is an α2-adrenoceptor antagonist, and when applied to slices, it increased catecholamine concentration and duration, demonstrating that we are detecting neuronal release of NE. Furthermore, we used ELISAs to quantify the extent to which the α2-adrenoceptor affects cytokine production, providing further evidence neuronal-regulated immune signaling in the white pulp region of the spleen. Supported by grants from NIH (R01AI151552, R01NS121426)

Intravital Longitudinal Three-Photon Imaging of Lymphocyte Migration in the Mouse Spleen.

Abstract For the last 20 years, intravital two-photon (2P) imaging has been a powerful tool to visualize lymphocyte dynamics in mouse lymphoid organs such as bone marrows and lymph nodes. Although spleen is a key lymphoid organ for adaptive immunity against blood-derived antigens, the lymphocyte dynamics in the spleen are poorly understood because intravital 2P imaging of spleen is challenging. Visualizing the white pulp in the spleen where most lymphocytes are located requires the excitation light to propagate through the red pulp which contains a lot of blood, causing high light-scattering. In addition, intravital spleen imaging suffers from motion artifact due to the mouse breathing motion. To overcome these challenges, we applied three-photon (3P) microscopy for spleen imaging, which can reduce light scattering and improve image contrast in deeper regions compared to 2P microscopy. We also designed a new implantable, chronic imaging window for reducing spleen motion in our up-light microscope. We could identify white pulp regions by in vivo labeling of the marginal zone of white pulp. Using 3P microscopy at 1300 nm wavelength, we could visualize EGFP+ lymphocytes in white pulps at approximately 400–500 μm depth below the surface while 2P microscopy at 920 nm could only reach imaging depths of 160–250 μm in the same region. We then determined the temperature of the imaging window that is required for maintaining normal lymphocyte motility during imaging by monitoring the lymphocyte motility at different temperatures. This intravital longitudinal 3P imaging technique has the potential to examine lymphocyte dynamics in blood-derived antigen-induced inflammatory process in the spleen.

Stable Lanthanide–Organic Frameworks: Crystal Structure, Photoluminescence, and Chemical Sensing of Vanillylmandelic Acid as a Biomarker of Pheochromocytoma

Several isostructural lanthanide metal-organic frameworks, viz. [Ln(DCHB)1.5phen]n (Ln-MOFs, where Ln = Eu for 1, Tb for 2, Sm for 3 and Dy for 4), are successfully synthesized through the hydrothermal reactions of 4'-di(4-carboxylphenoxy)hydroxyl-2, 2'-bipyridyl (H2DCHB) and lanthanide nitrates as well as chelator 1,10-phenantroline (phen). These structures are characterized by single-crystal X-ray diffraction, and the representative Ln-MOF 1 is a fivefold interpenetrated framework with the uncoordinated Lewis base N sites form DCHB2- ligands. The photoluminescence research studies reveal that Ln-MOFs 1-4 exhibit characteristic fluorescent emissions from ligand-induced lanthanide Ln(III) ions, while the single-component emission spectra of Ln-MOF 4 are all located in a white region under different excitations. The absence of coordinated water and the interpenetration property of the structures are conducive to the structure rigidity, and the results display that Ln-MOF 1 has high thermal/chemical stabilities in common solvents and a wide pH range as well as the boiling water. Notably, luminescent sensing studies reveal that Ln-MOF 1 with prominent fluorescence properties can perform in highly sensitive and selective sensing of vanillylmandelic acid (VMA) in aqueous systems (KSV = 562.8 L·mol-1; LOD = 4.6 × 10-4 M), which can potentially establish a detection platform for the diagnosis of pheochromocytoma via multiquenching mechanisms. Moreover, the 1@MMMs sensing membranes comprised of Ln-MOF 1 and a poly(vinylidene fluoride) (PVDF) polymer can also be facilely developed for VMA detection in aqueous media, suggesting the enhanced convenience and efficiency of practical sensing applications.

Emergence of a Euglena bioconvection spot controlled by non-uniform light

Microorganisms possess taxes, which are the behavioral response to stimuli. The interaction between taxis and fluid dynamic instability leads to a macroscopic flow called bioconvection. In this study, we demonstrated that an isolated, single, three-dimensional bioconvection cell can exist within Euglena suspension. The isolated convection cell was named a “bioconvection spot.” To reveal the formation of this bioconvection spot in a cylindrical container, position-control experiments were designed in a non-uniform light environment. Upon exposure of Euglena suspensions to varying light conditions with white and red regions, Euglena was determined to aggregate into the red (darker) region. This was attributed to its phototactic response of Euglena, causing its movement toward a darker environment and away from a strong light. Thus, the bioconvection spot was created by manipulating the local cell density of the suspension and the light environments. Using our experimental setup, we observed the structure of the spot and established that it radiated pulses of local cell densities of Euglena.

Micro- and Macro-scale Mechanical Properties of Meta-cherts as Concrete Aggregates

This paper presents the measurement of the tensile strength, Young’s modulus, and linear coefficient of thermal expansion in a meta-chert. Two areas are targeted in this aggregate - a white area where quartz grains are densely compacted and a gray area where the quartz grains are coarser. The macro- and micro-scale data are compared. Young’s modulus is not significantly different between macro-scale compression and micro-scale tension loading in the white region. Macro-scale splitting and micro-scale direct tensile strengths exhibit similar bimodal behavior due to the failure mechanisms of these two distinct areas. The macro- and micro-scale coefficients of thermal expansion are similar for the gray region, reflecting the quartz nature. Conversely, the micro-scale coefficient of thermal expansion of the white area shows a different behavior.

Luminescence characteristics of Ce3+/Eu2+ activated (Ba, Sr)3YB3O9 phosphors

The Ce3+/Eu2+ activated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors were prepared using solid state reactions under the reducing atmosphere. Then, their phase and fluorescence performance were investigated carefully. The XRD measurements demonstrate that the synthesized phosphors have the single phase. For the Ce3+/Eu2+ single activated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors, they respectively show blue and yellow emission, meaning it is possible to generate white light by the Ce3+/Eu2+ coactivated phosphors. Due to the Ce3+ → Eu2+ energy transfers, tunable luminescence was generated by the Ce3+/Eu2+ coactivated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors. The light of most of the Ce3+/Eu2+ coactivated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors locates in the white light region. In addition, the substitution of Sr2+ to Ba2+ benefits to obtain the full spectrum white light.

Chromium-doped ZnO nanoparticles synthesized via auto-combustion: Evaluation of concentration-dependent structural, band gap-narrowing effect, luminescence properties and photocatalytic activity

Herein we report the effect of the Cr3+ content on the distinctive features of the first-ever auto-combustion-synthesis-produced Cr3+ doped ZnO nanoparticles utilizing leucine as the fuel. To assess the impact of fuel and Cr3+ content on the structural, optical, and luminescence characteristics, as-synthesized powders were systematically examined using powder XRD, UV–Visible, and Photoluminescence spectroscopy. Structural studies show that the exothermicity of the redox mixture containing oxidizer and fuel combination leads to the development of polycrystalline, single-phase, and nanosized particles. XRD analysis shows that, reduced crystallite size with Cr3+ content. In contrast, other characteristics like lattice parameters, unit cell volume, strain, and dislocation density, were shown to increase linearly with Cr3+ concentration up to 7 mol%. Additionally, it is seen that the predicted Urbach energy values rise as Cr3+ is added to the ZnO host matrix, indicating that the substitution of Cr3+ for Zn in the host ZnO lattice has increased structural disorder. In contrast to the other samples, the 5 mol% Cr3+ doped ZnO sample exhibits the emission near the white region according to the PL emission measurements. Furthermore, the photocatalytic activity of the as-prepared Cr3+ doped ZnO NPs was examined. It was found that the as-prepared samples exhibit outstanding photocatalytic activity in the visible wavelength region against Malachite Green (MG) dye. Among all, 9 mol% Cr3+ doped ZnO has shown the maximum 95.4% degradation against MG dye. All the investigated results conclude that the produced Cr3+ doped ZnO nanoparticles could be exploited in a variety of upcoming optoelectronic and photocatalytic applications.

Investigation of aluminum current collector degradation in lithium-ion batteries using glow discharge optical emission spectrometry

In this work, we employed glow discharge optical emission spectrometry (GD-OES) depth profiling as a fast and semi-quantitative method to investigate the aluminum (Al) current collector degradation in commercial lithium cobalt oxide (LCO) pouch cells with no Al2O3 pretreatment. After battery aging, a heterogeneous deposit was found on the surface of the cathode. Gray hotspot areas within an extensive pale white region were formed. Consistent with energy dispersive X-ray (EDX) analysis of micro-cross sections milled via targeted focused ion beam (FIB), an Al-containing layer of approximately 3 μm can be observed using GD-OES. We attribute one main cause of this layer is the degradation of the Al current collector. The nonuniform growth of this layer was investigated by performing GD-OES depth profiling at different in-plane positions. We found that the gray area has a higher mass concentration of Al, probably in metallic form, whereas the white area was probably covered more homogeneously with Al2O3, resulting from the inhomogeneous distribution of the pitting positions on the current collector. Compared to FIB-EDX, GD-OES enables a faster and more convenient depth profile analysis, which allows the more productive characterization of lithium-ion batteries (LIBs), and consequently benefits the development of preferable battery materials.

Downconverted significant luminescence enhancement and structural confinement of a dichromatic nanophosphor for potential applications in NUV-triggered cool pc-WLEDs

Trivalent rare-earth ions activated phosphor-converted near ultraviolet (NUV) triggered white light-emitting diodes (WLEDs) are nowadays being explored as a prominent light source, in the field of lighting. Herein, we prepared a sequence of single-phase Gd2O3:Dy3+,Li+nanophosphor via chemical co-precipitation techniques for the applications in cool pc-WLEDs. To examine the crystal structure, luminescent characteristics, and potential applications of WLEDs, a systematic and comprehensive analysis was conducted. This study extensively investigated the effect of Li+ on the Gd2O3:Dy3+white-emitting nanophosphor. The phase purity and crystal structure of nanophosphors were characterized via powder X-ray diffraction (XRD) analysis. Rietveld refinement clearly quantified that the Gd2O3 host possesses two non-equivalent cationic sites that are coordinated sixfold. The interior morphology and elemental composition were illustrated by high-resolution transmission electron microscopy (HR-TEM) and energy dispersive spectroscopy (EDS). These nanophosphors effectively exhibit dichromatic significant photoluminescence (PL) emission bands of Dy3+ ion for blue and yellow color at 486 and 574 nm, while triggered in the NUV range. The blending of blue and yellow color lights yields a broad spectrum of light that appears white color to the human eye. Besides, it has been observed that the incorporation of Li+ significantly enhances the PL-emission intensity. The critical distance between Gd3+ and Dy3+ was determined, and it showed that the electric multipolar interaction was responsible for the energy transfer quenching mechanism. The colorimetric performance reveals that the CIE coordinates fall within the white region of the color space and that the correlated color temperature (CCT) is substantially higher than 4000 K. The lowest color purity (CP) was found to be 4.0% for x = 2 at.%Li+ ion concentration under excitation wavelength 350 nm. These findings suggest that the prepared nanophosphors are a suitable candidate for application in NUV-triggered cool-WLEDs.

White and tunable light emission of Ho3+ and Pr3+ ions co-doped phosphate glasses

The Ho3+ and Pr3+ ions co-doped phosphate glasses were prepared by melt quenching procedure with the various composition of (70-x-y)P2O5 + 20SiO2 + 10CaO + xHo2O3 + yPr2O3 (x = 0.4, 0.6, 0.8, 1.0 mol%, y = 0.6, 0.8, 1.0 mol%). The structural investigation (based on X-ray diffraction analysis) confirmed amorphous character of these glass materials. The optical properties were studied. The glass samples have strong absorption at 360 nm, and the excitation light at 360 nm can excite Ho3+ and Pr3+ ions very well, causing them to produce synergistic luminescence. The glass sample 68.8P2O5 + 20SiO2 + 10CaO + 0.4Ho2O3 + 0.8Pr2O3 emits strong white light under 360 nm excitation. The chromaticity coordinate values are x = 0.3378, y = 0.3472 in white light region, and it has a moderate correlated color temperature (CCT) of 5277 K. Decay time data reveals that there is energy transfer from Pr3+ to Ho3+ ions. This glass will be a good material for white light and tunable light emitting.

Прогноз температуры поверхности моря и приземной температуры воздуха по совместной модели океан – атмосфера для региона Белого моря в летний период

The results of forecasting the fields of hydrometeorological parameters with a coupled ocean-atmosphere system for the White Sea region for the period of June 2–September 1, 2015 are presented. The coupled system included the atmospheric (WRF-ARW), oceanic (ROMS) and wave (SWAN) models. Sea surface temperature (SST) and 2 m air temperature forecast skill scores are obtained. A systematic overestimation of the computed SST values relative to the OISST analysis data is 0.4 °C. The 2 m air temperature forecasts were generally more successful when using the coupled system than when using the WRF-ARW, and the improvement was observed mainly in the land areas immediately adjacent to the White Sea. Time intervals in which the influence of the sea on the 2 m air temperature forecasts was maximum and minimum are given. Keywords: coupled ocean-atmosphere system, ocean-atmosphere interaction, White Sea, WRF-ARW, ROMS, SWAN