Crystal structure and luminescence properties of the blue‐green‐emitting Ba9(Lu,Y)2Si6O24:Ce3+ phosphor

Samples of the Ba₉(Lu_2‐xY_x)Si₆O₂₄:Ce³⁺ (x = 0–2) blue‐green phosphors were synthesized by solid‐state reactions. All the samples exhibited a rhombohedral crystal structure. As the Y³⁺ concentration increased, the diffraction peaks shifted to the small angle region and the lattice parameters increased due to the larger ionic radius of Y³⁺ (r = 0.900 Å) compared with that of Lu³⁺ (r = 0.861 Å). Under 400 nm excitation, samples exhibited strong blue‐green emissions around 490 nm. The emission bands had a slight blue shift that resulted from weak crystal‐field splitting with increasing Y³⁺ concentration. Luminescence intensity and quantum efficiency (QE) decreased with increasing Y³⁺ concentration. The internal QE decreased from 74 to 50% and the external QE decreased from 50 to 34% as x increased from 0 to 2. The thermal stability of the Lu series was better than that of the Y‐series. The excitation band peak around 400 nm matched well with the emission light from the efficient near‐ultraviolet (NUV) chip. These results indicate promising applications for these NUV‐based white light‐emitting diodes.     

Luminescence enhancement of (Sr1–xMx)2SiO4:Eu2+ phosphors with M (Ca2+/Zn2+) partial substitution for white light‐emitting diodes

Eu²⁺‐doped Sr₂SiO₄ phosphor with Ca²⁺/Zn²⁺ substitution, (Sr_1–xM_x)₂SiO₄:Eu²⁺ (M = Ca, Zn), was prepared using a high‐temperature solid‐state reaction method. The structure and luminescence properties of Ca²⁺/Zn²⁺ partially substituted Sr₂SiO₄:Eu²⁺ phosphors were investigated in detail. With Ca²⁺ or Zn²⁺ added to the silicate host, the crystal phase could be transformed between the α‐form and the β‐form of the Sr₂SiO₄ structure. Under UV excitation at 367 nm, all samples exhibit a broad band emission from 420 to 680 nm due to the 4f⁶5d¹ → 4f⁷ transition of Eu²⁺ ions. The broad emission band consists of two peaks at 482 and 547 nm, which correspond to Eu²⁺ ions occupying the ten‐fold oxygen‐coordinated Sr.(I) site and the nine‐fold oxygen‐coordinated Sr.(II) site, respectively. The luminescence properties, including the intensity and lifetime of Sr₂SiO₄:Eu²⁺ phosphors, improved remarkably on Ca²⁺/Zn²⁺ addition, and promote its application in white light‐emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.     

Concentration‐dependent studies of Nd3+‐doped zinc phosphate glasses for NIR photoluminescence at 1.05 μm

Nd³⁺‐doped lead‐free zinc phosphate glasses with the chemical compositions (60‐x) NH₄H₂PO₄ + 20ZnO + 10BaF₂ + 10NaF + xNd₂O₃ (where x = 0.5, 1.0, 1.5, 2.0 and 2.5 mol%) were prepared using a melt quenching technique. Vibrational bands were assigned and clearly elucidated by Raman spectral profiles for all the glass samples. Judd–Ofelt (J–O) intensity parameters (Ω_λ: λ = 2, 4, 6) were obtained from the spectral intensities of different absorption bands of Nd³⁺ ions. Radiative properties such as radiative transition probabilities (A_R), radiative lifetimes (τ_R) and branching ratios (β_R) for different excited states were calculated using J–O parameters. The near infrared (NIR) photoluminescence spectra exhibited three emission bands (⁴F_3/2 level to ⁴I_13/2, ⁴I_11/2 and ⁴I_9/2 states) for all the concentrations of Nd³⁺ ions. Various luminescence properties were studied by varying the Nd³⁺ concentration for the three spectral profiles. Fluorescence decay curves of the ⁴F_3/2 level were recorded. The energy transfer mechanism that leads to quenching of the ⁴F_3/2 state lifetimes was discussed at higher concentration of Nd³⁺ ions. These glasses are suggested as suitable hosts to produce efficient lasing action in NIR region at 1.05 μm.     

Lasing transition at 1.06 μm emission in Nd3+‐doped borate‐based tellurium calcium zinc niobium oxide glasses for high‐power solid‐state lasers

The spectroscopic properties of Tellurium Calcium Zinc Niobium oxide Borate (TCZNB) glasses of composition (in mol%) 10TeO₂ + 15CaO + 5ZnO + 10 Nb₂O₅ + (60 – x)B₂O₃ + Nd₂O₃ (x = 0.1, 0.5, 1.0 or 1.5 mol%) have been investigated experimentally. The three phenomenological intensity parameters Ω₂, Ω_4, Ω₆ have been calculated using the Judd–Ofelt theory and in turn radiative properties such as radiative transition probabilities, emission cross‐sections, branching ratios and radiative lifetimes have been estimated. The trend found in the JO intensity parameter is Ω₂ > Ω₆ > Ω₄ If Ω₆ > Ω₄, the glass system is favourable for the laser emission ⁴F_3/2 → ⁴I_11/2 in the infrared (IR) wavelength. The experimental values of branching ratio of ⁴F_3/2 → ⁴I_11/2 transition indicate favourable lasing action with low threshold power. The evaluated total radiative transition probabilities (A_T), stimulated emission cross‐section (σ_e) and gain bandwidth parameters (σ_e × Δλ_p) were compared with earlier reports. An energy level analysis has been carried out considering the experimental energy positions of the absorption and emission bands.     

Independent associations of TOMM40 and APOE variants with body mass index

The TOMM40‐APOE variants are known for their strong, antagonistic associations with Alzheimer's disease and body weight. While a stronger role of the APOE than TOMM40 variants in Alzheimer's disease was suggested, comparative contribution of the TOMM40‐APOE variants in the regulation of body weight remains elusive. We examined additive effects of rs2075650 and rs157580 TOMM40 variants and rs429358 and rs7412 APOE variants coding the ε2/ε3/ε4 polymorphism on body mass index (BMI) in age‐aggregated and age‐stratified cohort‐specific and cohort‐pooled analysis of 27,863 Caucasians aged 20–100 years from seven longitudinal studies. Minor alleles of rs2075650, rs429358, and rs7412 were individually associated with BMI (β = ?1.29, p = 3.97 × 10^?9; β = ?1.38, p = 2.78 × 10^?10; and β = 0.58, p = 3.04 × 10^?2, respectively). Conditional analysis with rs2075650 and rs429358 identified independent BMI‐lowering associations for minor alleles (β = ?0.63, p = 3.99 × 10^?2 and β = ?0.94, p = 2.17 × 10^?3, respectively). Polygenic mega‐analysis identified additive effects of the rs2075650 and rs429358 heterozygotes (β = ?1.68, p = 3.00 × 10^?9), and the strongest BMI‐lowering association for the rs2075650 heterozygous and rs429358 minor allele homozygous carriers (β = ?4.11, p = 2.78 × 10^?3). Conditional analysis with four polymorphisms identified independent BMI‐lowering (rs2075650, rs157580, and rs429358) and BMI‐increasing (rs7412) associations of heterozygous genotypes with BMI. Age‐stratified conditional analysis revealed well‐powered support for a differential and independent association of the rs429358 heterozygote with BMI in younger and older individuals, β = 0.58, 95% confidence interval (CI) = ?1.18, 2.35, p = 5.18 × 10^?1 for 3,068 individuals aged ≤30 years and β = ?4.28, CI = ?5.65, ?2.92, p = 7.71 × 10^?10 for 6,052 individuals aged >80 years. TOMM40 and APOE variants are independently and additively associated with BMI. The APOE ε4‐coding rs429358 polymorphism is associated with BMI in older individuals but not in younger individuals.     

Luminescence properties of Ce3+ in orthosilicate oxyapatite NaY9(SiO4)6O2

Ce³⁺‐doped orthosilicate oxyapatite NaY₉(SiO₄)₆O₂ phosphors NaY_9–x(SiO₄)₆O₂:xCe³⁺ were prepared by a conventional high‐temperature solid‐state reaction method, and their spectroscopic characteristics were systematically investigated. The occupancies of Ce³⁺ ions at two different sites (Wyckoff 6 h and 4f sites) in NaY₉(SiO₄)₆O₂ were determined. The influence of doping concentration on the emission intensity of Ce³⁺ was investigated and the critical distance Rc was estimated in terms of the concentration quenching data.     

Mycelial cultivation of <Emphasis Type="Italic">Phellinus linteus</Emphasis> using cheese-processing waste and optimization of bioconversion conditions

A medicinal mushroom, Phellinus linteus, was successfully cultivated using a cheese-processing waste, whey, and the optimal bioconversion conditions for the maximum mycelial growth rate was also estimated through solid-state cultivation experiments. Response surface analysis with a face-centered design (center point replication = 5) was applied to statistically approximate the simultaneous effects of the three variables, i.e., substrate concentration (10–30 g lactose l⁻¹), temperature (20–30°C), and pH (4–6), on the mycelial growth rate of P. linteus. The following is a partial cubic model where η is the mycelial growth rate (K _r ) and x _k is the corresponding variable term (k = substrate concentration, temperature, and pH in order): η = −23.8 + 8.67 × 10⁻² x ₁ + 1.48x ₂ + 1.77x ₃ + 8.00 × 10⁻⁴ x ₁ x ₂ + 7.25 × 10⁻² x ₁ x ₃ + 5.13 × 10⁻² x ₂ x ₃ −1.28 × 10⁻² x ₁² –3.18 × 10⁻² x ₂². −2.64 × 10⁻¹ x ₃² −3.28 × 10⁻³ x ₁ x ₂ x ₃ + 4.68 × 10⁻⁴ x ₁² x ₂. The produced response surface model proved to be significant (r ² > 0.99, P-value <0.0001, coefficient of variation <5%) to describe the explored space. Temperature was found to be the most significant factor of dominant effects on the mycelial growth rate, and other variables such as temperature², pH, pH², and (substrate concentration² × temperature) also showed significant effects on the model output. The maximum mycelial growth rate was predicted to be 2.80 mm d⁻¹ at 29.7 g lactose l⁻¹, 26.2°C, and pH 5. Our results proved a good potential of whey to serve as an alternative growth medium for cultivating P. linteus mycelia. This may provide another potential for managing this nutrient-rich waste in a cost-effective way.     

The luminescent properties and crystal structure of Sr(1.5‐x)‐(1.5y)Mg0.5SiO4:xEu2+,yCe3+ blue phosphor synthesized by co‐precipitation method

In order to improve the luminescent performance of silicate blue phosphors, Sr_{(1.5‐x)‐(1.5y)}Mg_0.5SiO₄:xEu²⁺,yCe³⁺ phosphors were synthesized using one‐step calcination of a precursor prepared by chemical co‐precipitation. The crystal structure and luminescent properties of the phosphors were analyzed using X‐ray diffraction and fluorescence spectrophotometry, respectively. Because the activated ions (Eu²⁺) can occupy two different types of sites (Sr₁ and Sr₂), the emission spectrum of Eu²⁺ excited at 350 nm contains two single bands (EM₁ and EM₂) in the wavelength range 400–550 nm, centered at 463 nm, and the emission intensity first increases and then decreases with increasing concentrations of Eu²⁺ ions. Co‐doping of Ce³⁺ ions can greatly enhance the emission intensity of Eu²⁺ by transferring its excitation energy to Eu²⁺. Because of concentration quenching, a higher substitution concentration of Ce³⁺ can lead to a decrease in the intensity. Meanwhile, the quantum efficiency of the phosphor is improved after doping with Ce³⁺, and a blue shift phenomenon is observed in the CIE chromaticity diagram. The results indicate that Sr_{(1.5‐x)‐(1.5y)}Mg_0.5SiO₄:xEu²⁺,yCe³⁺ can be used as a potential new blue phosphor for white light‐emitting diodes.     

η-N-succinimidato complexes of iron, molybdenum and tungsten as reversible inhibitors of papain

Recently we have found that the metallocarbonyl complexes (η⁵-C₅H₅)M(CO)_x(η¹-N-maleimidato) (M = Fe, Mo, W; x = 2 or 3) bearing a maleimide function were irreversible inhibitors of the enzyme papain. To get further insight into the binding mechanism of these compounds we synthesized the related complexes (η⁵-C₅H₅)M(CO)_x(η¹-N-succinimidato) (M = Fe, Mo, W; x = 2 or 3) that lacked the ethylenic bond responsible for alkylation of the cysteine 25 thiol group in the papain‘s catalytic pocket. We performed kinetic studies of the interaction of the synthesized complexes towards papain. We found that they act as reversible inhibitors of the enzyme with IC₅₀ values in the range 480–1700 μM. Docking experiments confirmed binding of these complexes to the enzyme’s catalytic pocket.     

The decomposition of triphenylimidazole‐para‐acetate follows specific base catalysis and can be conveniently followed by fluorescence

The kinetics of the decomposition reaction of 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)phenyl acetate ( 1 ) in basic alcoholic media was investigated, using a simple fluorescence (FL) spectrophotometric procedure. The process was conveniently studied using FL, since the triphenylimidazole‐derived ester 1 and its reaction products (the corresponding phenol 2 and phenolate 2 ^? ) are all highly fluorescent (Φ_FL > 37%). By carefully selecting excitation and emission wavelengths, observed rate constants k₁ in the order of 10^?3 to 10^?2 s^?1 were obtained from either reactant consumption (λ_ex = 300 nm, λ_em = 400 nm) or product formation (λ_ex = 350 nm, λ_em = 475 nm); these were shown to be kinetically equivalent. Intensity‐decay time profiles also gave a residual FL intensity parameter, shown to be associated to the distribution of produced species 2 and 2 ^? , according to the basicity of the medium. Studying the reaction in both methanol (MeOH) and isopropanol (iPrOH), upon addition of HO^?, provided evidence that the solvent's conjugate base is the active nucleophilic species. When different bases were used (tBuO^?, HO^?, DBU and TEA), bimolecular rate constants k_bim ranging from 4.5 to 6.5 L mol^?1 s^?1 were obtained, which proved to be non‐dependent on the base pK_aH, suggesting specific base catalysis for the decomposition of 1 in alcoholic media.     

Modelling nitrogen-corrected apparent metabolisable energy requirement for egg production of 3 BW types of Yellow Broiler breeder hens during the egg-laying period

Accurate prediction of energy requirement is important in formulating diets, but an energy model for Yellow Broiler breeder hens is publicly unavailable. The objective of this study was to establish energy prediction models for the nitrogen-corrected apparent metabolisable energy (AMEn) requirement of different categories of Yellow Broiler breeder hens during the egg-laying period. Data for modelling were collected from research papers, public databases and production data from companies. Breeder hens were generally categorised into three BW types: heavy, medium and light (HBWT, MBWT and LBWT). Published articles were cited for providing coefficients of AMEn maintenance requirement (AMEnm, 101 kcal/kg BW^0.75, 423 KJ/kg BW^0.75) and growth requirement (AMEng, 5.33 kcal/g, 22.3 KJ/g), respectively. Models of AMEn for egg production (AMEnp) were established from the known daily intake of AMEn (AMEni) and those of maintenance and growth by the factorial approach: AMEnp = AMEni ? AMEnm ? AMEng. For the three types of hens, AMEnp HBWT (kcal, KJ) = 2.55 kcal (10.7 KJ) × egg mass (EM, g); AMEnp MBWT (kcal, KJ) = 2.70 kcal (11.3 KJ) × EM (g), and AMEnp LBWT (kcal, KJ) = 2.94 kcal (12.3 KJ) × EM (g) were determined. The total AMEni requirements, depending on Gompertz models, were HBWT: BW (g) = 3 144 × e^{?EXP(?0.162×(week of age (wk)?15.6))}; MBWT: BW (g) = 2 526 × e^{?EXP(?0.333×(wk?19.1))}; LBWT: BW (g) = 1 612 × e^{?EXP(?0.242×(wk?16.5))}. Models of egg production, HBWT: egg production (%) = 124 × e^?0.017×wk/(1 + e^{?0.870×(wk?26.2)}); MBWT: egg production (%) = 144 × e^?0.020×wk/(1 + e^{?0.751×(wk?24.9)}); LBWT: egg production (%) = 163 × e^?0.024×wk/(1 + e^{?0.476×(wk?26.5)})) and egg weight for each wk of the three types of hens during the egg-laying period were all established. These models showed good applicability in simulating and predicting the literature or production data.     

Tunable emission from LiBaBO3:Eu3+;Bi3+ phosphor for solid‐state lighting

Europium (Eu³⁺) and bismuth (Bi³⁺) co‐activated LiBaBO₃ powder phosphors were synthesized by a solid‐state reaction and the structure, particle morphology, optical and photoluminescent properties were investigated. X‐Ray diffraction patterns of the LiBaBO₃ phosphors crystallized in a pure monoclinic phase, i.e. there were no secondary phases due to either incidental impurities or undecomposed starting materials. Scanning electron microscopy images showed that the powders were made up of fluffy needle‐like particles that were randomly aligned. The band‐gap of the LiBaBO₃ host was estimated to be 3.33 eV from the UV/vis absorption data. Blue emission was observed from the LiBaBO₃ host, which is ascribed to self‐activation of the host matrix. In addition, greenish‐blue (493 nm) and red (613 nm) emissions were observed from europium‐doped samples and were attributed to the emissions of Eu²⁺ and Eu³⁺, respectively. Furthermore, after codoping with Bi³⁺, the emission intensity of Eu³⁺ located at 613 nm was significantly enhanced. From the Commission Internationale de I′Eclairage (CIE) color coordinates, white emission was observed from LiBa_1–xBO₃:xEu³⁺ (x = 0.020 and 0.025) phosphor powders with color coordinates of x = 0.368, y = 0.378 and x = 0.376, y = 0.366, respectively.     

Improved Bulk Materials with Thermoelectric Figure‐of‐Merit Greater than 1: Tl10–xSnxTe6 and Tl10–xPbxTe6

Noting the steadily worsening problem of depleted fossil fuel sources, alternate energy sources have become increasingly important; these include thermoelectrics, which may use waste heat to generate electricity. To be economically viable, the thermoelectric figure‐of‐merit, zT, which is related to the energy conversion efficiency, needs to be in excess of unity (zT > 1). Tl₄SnTe₃ and Tl₄PbTe₃ were reported to attain a thermoelectric figure‐of‐merit zT _max = 0.74 and 0.71, respectively, at 673 K. Here, the thermoelectric properties of both materials are presented as a function of x in Tl_10–x Sn _x Te₆ and Tl_10–x Pb _x Te₆, with x varying between 1.9 and 2.05, culminating in zT values in excess of 1.2. These materials are charge balanced when x = 2, according to (Tl⁺)₈(Sn²⁺)₂(Te^2?)₆ and (Tl⁺)₈(Pb²⁺)₂(Te^2?)₆ (or: (Tl⁺)₄Pb²⁺(Te^2?)₃). Increasing x causes an increase in valence electrons, and thus a decrease in the dominating p‐type charge carriers. Larger x values occur with a smaller electrical conductivity and a larger Seebeck coefficient. In each case, the lattice thermal conductivity remains under 0.5 W m^?1 K^?1, resulting in several samples attaining the desired zT _max > 1. The highest values thus far are exhibited by Tl_8.05Sn_1.95Te₆ with zT = 1.26 and Tl_8.10Pb_1.90Te₆ with zT = 1.46 around 685 K.     

Flight of the honey bee VI: energetics of wind tunnel exhaustion flights at defined fuel content,speed adaptation and aerodynamics

To gain information on extended flight energetics, quasi-natural flight conditions imitating steady horizontal flight were set by combining the tetheredflight wind-tunnel method with the exhaustion-flight method. The bees were suspended from a two-component aerodynamic balance at different, near optimum body angle of attack and were allowed to choose their own speed: their body mass and body weight was determined before and after a flight; their speed, lift, wingbeat frequency and total flight time were measured throughout a flight. These values were used to determine thrust, resultant aerodynamic force (magnitude and tilting angle), Reynolds number, total flight distance and total flight impulse. Flights in which lift was body weight were mostly obtained. Bees, flown to complete exhausion, were refed with 5, 10, 15 or 20 l of a 1.28-mol·l^-1 glucose solution (energy content w=18.5, 37.0, 55.5 or 74.0 J) and again flown to complete exhaustion at an ambient temperature of 25±1.5°C by a flight of known duration such that the calculation of absolute and relative metabolic power was possible. Mean body mass after exhaustion was 76.49±3.52 mg. During long term flights of 7.47–31.30 min similar changes in flight velocity, lift, thrust, aerodynamic force, wingbeat frequency and tilting angle took place, independent of the volume of feeding solution. After increasing rapidly within 15 s a more or less steady phase of 60–80% of total flight time, showing only a slight decrease, was followed by a steeper, more irregular decrease, finally reaching 0 within 20–30 s. In steady phases lift was nearly equal to resultant aerodynamic force; tilting angle was 79.8±4.0°, thrust to lift radio did not vary, thrust was 18.0±7.4% of lift, lift was somewhat higher/equal/lower than body mass in 61.3%, 16.1%, 22.6% of all totally analysable flights (n=31). The following parameters were varied as functions of volume of feeding solution (5–20 l in steps of 5 l) and energy content. (18.5–74.0 J in steps of 18.5 J): total flight time, velocity, total flight distance, mean lift, thrust, mean resultant aerodynamic force, tilting angle, total flight impulse, wingbeat frequency, metabolic power and metabolic power related to body mass, the latter related to empty, full and mean (=100 mg) body mass. The following positive correlations were found: L=1.069·10^-9 f ^2.538; R=1.629·10^-9 f ^2.464; P _m=7.079·10^-8 f ^2.456; P _m=0.008v+0.008; P _m=18.996L+0.022; P _m=19.782R+0.021; P _m=82.143T+0.028; P _m=1.245·bm _f ^1.424 ; P _{mrel e}=6.471·bm _f ^1.040 ; =83.248+0.385. The following negative correlations were found: V=3.939–0.032; T=1.324·10^-4–0.038·10^-4. Statistically significant correlations were not found in T(f), L(), R(), f(), P _m(bm _e), P _{m rel e}(bm _e), P _{m rel f}(bm _e), P _{m rel f}(bm _f).Abbreviations A(m²) frontal area - bl(m) body length - bm(mg) body mass - c(mol·1^-1) glucose concentration of feeding solution - c _D (dimensionless) drag coefficient, related to A - D(N) drag - F _w(N) body weight - F _wp weight of paper fragment lost at flight start - f wingbeat frequency (s^-1) - g(=9.81 m·s^-2) gravitational acceleration - I(Ns)=R(t) dt total impulse of a flight - L(N) lift vertical sustaining force component - P _m(J·s^-1=W) metabolic power - P_{m ret} (W·g^-1) metabolic power, related to body mass - R(N) resultant aerodynamic force - Re v·bl·v ^-1 (dimensionless) Reynolds number, related to body length - s(m) v(t) dt virtual flight distance of a flight - s(km) total virtual flight distance - T (N) thrust horizontal force component of horizontal flight - T _a (°C) ambient temperature - t(s) time - t _tot (s or min) total flight time - v(m·s^-1) flight velocity - v(l) volume of feeding solution - W (J) energy and energy content of V - ( °) body angle of attack between body longitudinal axis and flow direction - ( °) tilting angle ( 90°) between R and the horizont in horizontal flight v(=1.53·10^-5m²·s^-1 for air at 25°) kinematic viscosity - (=1.2 kg·m^-3 at 25°C) air density     

Long-term exposure of the freshwater shrimp Macrobrachium olfersii to elevated salinity: Effects on gill (Na,K)-ATPase α-subunit expression and K-phosphatase activity

The kinetic properties of a microsomal gill (Na⁺,K⁺)-ATPase from the freshwater shrimp, Macrobrachium olfersii, acclimated to 21‰ salinity for 10 days were investigated using the substrate p-nitrophenylphosphate. The enzyme hydrolyzed this substrate obeying cooperative kinetics at a rate of 123.6 ± 4.9 U mg^− 1 and K_0.5 = 1.31 ± 0.05 mmol L^− 1. Stimulation of K⁺-phosphatase activity by magnesium (V_max = 125.3 ± 7.5 U mg^− 1; K_0.5 = 2.09 ± 0.06 mmol L^− 1), potassium (V_max = 134.2 ± 6.7 U mg^− 1; K_0.5 = 1.33 ± 0.06 mmol L^− 1) and ammonium ions (V_max = 130.1 ± 5.9 U mg^− 1; K_0.5 = 11.4 ± 0.5 mmol L^− 1) was also cooperative. While orthovanadate abolished p-nitrophenylphosphatase activity, ouabain inhibition reached 80% (K_I = 304.9 ± 18.3 μmol L^− 1). The kinetic parameters estimated differ significantly from those for freshwater-acclimated shrimps, suggesting expression of different isoenzymes during salinity adaptation. Despite the ≈2-fold reduction in K⁺-phosphatase specific activity, Western blotting analysis revealed similar α-subunit expression in gill tissue from shrimps acclimated to 21‰ salinity or fresh water, although expression of phosphate-hydrolyzing enzymes other than (Na⁺,K⁺)-ATPase was stimulated by high salinity acclimation.     

A New Strategy for High‐Voltage Cathodes for K‐Ion Batteries: Stoichiometric KVPO4F

The exploration of high‐energy‐density cathode materials is vital to the practical use of K‐ion batteries. Layered K‐metal oxides have too high a voltage slope due to their large K⁺–K⁺ interaction, resulting in low specific capacity and average voltage. In contrast, the 3D arrangement of K⁺, with polyanions separating them, reduces the strength of the effective K⁺‐K⁺ repulsion, which in turn increases specific capacity and voltage. Here, stoichiometric KVPO₄F for use as a high‐energy‐density K‐ion cathode is developed. The KVPO₄F cathode delivers a reversible capacity of ≈105 mAh g^?1 with an average voltage of ≈4.3 V (vs K/K⁺), resulting in a gravimetric energy density of ≈450 Wh kg^?1. During electrochemical cycling, the K_xVPO₄F cathode goes through various intermediate phases at x = 0.75, 0.625, and 0.5 upon K extraction and reinsertion, as determined by ex situ X‐ray diffraction characterization and ab initio calculations. This work further explains the role of oxygen substitution in KVPO_4+xF_1?x: the oxygenation of KVPO₄F leads to an anion‐disordered structure which prevents the formation of K⁺/vacancy orderings without electrochemical plateaus and hence to a smoother voltage profile.     

A novel LC‐MS/MS method to quantify eumelanin and pheomelanin and their relation to UVR sensitivity – A study on human skin biopsies

Melanin in the skin can be divided into eumelanin and pheomelanin subtypes. Simultaneous quantification of these subtypes could clarify their relation to skin type and skin cancer development. We describe a novel, sensitive liquid chromatography–tandem mass spectrometry method to quantify two eumelanin markers, pyrrole‐2,3,5‐tricarboxylic acid (PTCA) and pyrrole‐2,3‐dicarboxylic acid (PDCA), and two pheomelanin markers, thiazole‐4,5‐dicarboxylic acid (TDCA) and thiazole‐2,4,5 tricarboxylic acid (TTCA), performed in a single run using the same biopsy. Volunteers with either Fitzpatrick skin type (FST) I/II or III/IV (n = 30) each provided a 4‐mm punch biopsy from the buttock. Upon analysis, the FST I + II group had significantly less of all four melanin biomarkers (PTCA, 0.75 ng/mm²; PDCA, 0.08 ng/mm²; TTCA, 0.24 ng/mm²; and TDCA, 0.10 ng/mm²) versus the FST III + IV group (PTCA, 4.89 ng/mm²; PDCA, 0.22 ng/mm²; TTCA, 2.61 ng/mm²; and TDCA, 0.72 ng/mm²), p ≤ 0.003. We find that this new LC‐MS/MS method is sensitive enough to quantify eumelanin and pheomelanin markers even in the lightest skin types.     

Three azido-, alk/phenoxido- and acetato-bridged tetranuclear nickel complexes featuring defective double-cubane

Three new tetranuclear nickel(II) complexes of general formula [Ni₄(L)₂(N₃)₂(CH₃COO)₂(CH₃O)₂]₂·xCH₃OH·yH₂O (HL = HL¹, HL² and HL³; x = 0, y = 1 for 1; x = 2, y = 0 for 2 and x = 2, y = 4 for 3) were synthesized and characterized by single crystal X-ray diffraction and magnetic measurements. Single crystal X-ray studies reveal that all three complexes exhibit similar tetranuclear face-shared defective double-cubane structure, having azido-, alk/phenoxido- and acetato-bridges. Magnetic susceptibility measurements on the complexes in the range of 300-2 K indicate ferromagnetic coupling between the metal ions. The slightly different magnetic behaviors observed are probably caused by subtle structural differences between the respective [Ni₄O₄N₂] cores induced by ligand variation.     

Synthesis and photoluminescence characteristics of Sm3+‐doped Bi4Si3O12 red‐emitting phosphor

A series of novel red‐emitting Sm³⁺‐doped bismuth silicate phosphors, Bi₄Si₃O₁₂:xSm³⁺ (0.01 ≤ x ≤ 0.06), were prepared via the sol–gel route. The phase of the synthesized samples calcinated at 800 °C is isostructural with Bi₄Si₃O₁₂ according to X‐ray diffraction results. Under excitation with 405 nm light, some typical peaks of Sm³⁺ ions centered at 566, 609, 655 and 715 nm are found in the emission spectra of the Sm³⁺‐doped Bi₄Si₃O₁₂ phosphors. The strongest peak located at 609 nm is due to ⁴G_5/2–⁶H_7/2 transition of Sm³⁺. The luminescence intensity reaches its maximum value when the Sm³⁺ ion content is 4 mol%. The results suggest that Bi₄Si₃O₁₂:Sm³⁺ may be a potential red phosphor for white light‐emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.     

Polysulfide‐Shuttle Control in Lithium‐Sulfur Batteries with a Chemically/Electrochemically Compatible NaSICON‐Type Solid Electrolyte

A NaSICON‐type Li⁺‐ion conductive membrane with a formula of Li_{1+ x} Y _x Zr_{2? x} (PO₄)₃ (LYZP) (x = 0–0.15) has been explored as a solid‐electrolyte/separator to suppress polysulfide‐crossover in lithium‐sulfur (Li‐S) batteries. The LYZP membrane with a reasonable Li⁺‐ion conductivity shows both favorable chemical compatibility with the lithium polysulfide species and exhibits good electrochemical stability under the operating conditions of the Li‐S batteries. Through an integration of the LYZP solid electrolyte with the liquid electrolyte, the hybrid Li‐S batteries show greatly enhanced cyclability in contrast to the conventional Li‐S batteries with the porous polymer (e.g., Celgard) separator. At a rate of C/5, the hybrid Li ||LYZP|| Li₂S₆ batteries developed in this study (with a Li‐metal anode, a liquid/LYZP hybrid electrolyte, and a dissolved lithium polysulfide cathode) delivers an initial discharge capacity of ≈1000 mA h g^?1 (based on the active sulfur material) and retains ≈90% of the initial capacity after 150 cycles with a low capacity fade‐rate of <0.07% per cycle.