Ratiometric luminescence thermometry employing luminescence within the biological transparency windows provides high potential for biothermal imaging. Nd3+ is a promising candidate for that purpose ...due to its intense radiative transitions within biological windows (BWs) I and II and the simultaneous efficient excitability within BW I. This makes Nd3+ almost unique among all lanthanides. Typically, emission from the two 4F3/2 crystal field levels is used for thermometry but the small ~100 cm−1 energy separation limits the sensitivity. A higher sensitivity for physiological temperatures is possible using the luminescence intensity ratio (LIR) of the emissive transitions from the 4F5/2 and 4F3/2 excited spin-orbit levels. Herein, we demonstrate and discuss various pitfalls that can occur in Boltzmann thermometry if this particular LIR is used for physiological temperature sensing. Both microcrystalline, dilute (0.1%) Nd3+-doped LaPO4 and LaPO4: x% Nd3+ (x = 2, 5, 10, 25, 100) nanocrystals serve as an illustrative example. Besides structural and optical characterization of those luminescent thermometers, the impact and consequences of the Nd3+ concentration on their luminescence and performance as Boltzmann-based thermometers are analyzed. For low Nd3+ concentrations, Boltzmann equilibrium starts just around 300 K. At higher Nd3+ concentrations, cross-relaxation processes enhance the decay rates of the 4F3/2 and 4F5/2 levels making the decay faster than the equilibration rates between the levels. It is shown that the onset of the useful temperature sensing range shifts to higher temperatures, even above ~ 450 K for Nd concentrations over 5%. A microscopic explanation for pitfalls in Boltzmann thermometry with Nd3+ is finally given and guidelines for the usability of this lanthanide ion in the field of physiological temperature sensing are elaborated. Insight in competition between thermal coupling through non-radiative transitions and population decay through cross-relaxation of the 4F5/2 and 4F3/2 spin-orbit levels of Nd3+ makes it possible to tailor the thermometric performance of Nd3+ to enable physiological temperature sensing.
•Two methods of color measurement were compared, a computer vision system (CVS) vs a traditional colorimeter.•Some color parameters differed significantly between the two color-assessment ...methods.•CVS color was more laborious to obtain, but was more accurate and representative, especially for non-uniformly colored samples.•CVS-generated color chips were more similar to the actual sample color in all trials.•CVS color was more accurate and precise for color traits compared with traditional colorimeter.
We investigate the availability and extent of environmental performance and objectives data reported in corporate social responsibility (CSR) reports published by the world largest food companies. ...Methods for content analysis that recognize two types of environmental information were implemented for reviewing 75 sustainability reports. Plant‐ and animal‐origin food companies responded to requirements of the Global Reporting Initiative (GRI) standards to communicate about their sustainable development. It was found that plant‐origin food companies' reporting was more compliant with GRI requirements. Information gaps within greenhouse gas (GHG) emissions data have been identified as a common characteristic for both food sectors. The most frequent performance indicators reported by companies were about water withdrawal. Average annual reductions in four major environmental dimensions such as energy consumption, GHG emissions, water withdrawal, and total waste were calculated. These results reveal patterns of food companies' behavior in CSR reporting.
The binary luminescence thermometry probe is prepared from Y2O3:Ho3+ and Mg2TiO4:Mn4+ powders. This probe facilitates self‐referencing temperature readouts with excellent repeatability from both ...emission intensity ratio and excited state lifetimes. The ratio of intensities of Mn4+ deep red emission from 2E, 4T2→4A2 electronic transitions, and Ho3+ green emission from 5F4,5S2 →5I8 electronic transitions provides temperature measurements over the room temperature to 100 °C temperature range with a superior relative sensitivity of 4.6% °C−1 and temperature resolution of 0.1 °C. Over the same temperature range, the temperature readout from the Mn4+ emission lifetime offers measurements with relative sensitivity better than 0.5% °C−1 and better than 0.2 °C in resolution.
The combination of Mn4+ and Ho3+ emissions facilitates highly sensitive and repeatable luminescence thermometry. It shows a superior temperature resolution which can be realized using cheap blue LED sources and which covers the most relevant temperature range from room temperature to 100 °C.
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•Charge transfer complex formation between TiO2 powder and phenol derivatives.•Visible-light-responsive inorganic/organic hybrids.•Conduction band edge determination of hybrids by ...cyclic voltammetry technique.•DFT calculations of electronic excitation spectra.
The charge transfer complex formation between TiO2 powder and variety of phenol derivatives (phenol, 4-nitrophenol, 4-bromophenol, 4-tert-butylphenol, hydroquinone) was achieved. The red-shift of optical absorption was observed upon surface modification of TiO2 powders with phenol derivatives. The influence of substituent functional groups in para position on the optical band gap and conduction band edge of inorganic/organic hybrids was studied using reflection spectroscopy and cyclic voltammetry. The experimental findings were supported by density functional theory calculations. The measured reflection spectra of surface-modified TiO2 powders with phenol derivatives were compared with calculated electronic excitation spectra of corresponding model systems.
MgTiO3 nanoparticles doped with Mn4+, with homogeneous size ranging about 63.1 ± 9.8 nm, were synthesized by a molten salt assisted sol gel method. These nanoparticles have been investigated as ...optical thermal sensors. The luminescence of tetravalent manganese ion in octahedral environment within the perovskite host presents drastic variations with temperature. Three different thermometry approaches have been proposed and characterized. Two luminescence intensity ratios are studied. Firstly between the two R-lines of Mn4+ emission at low temperature (−250 °C and −90 °C) with a maximal sensitivity of 0.9% °C−1, but also secondly between 2E → 4A2 (R-line) and the 4T2 → 4A2 transitions. This allows studying the temperature variation within a larger temperature range (−200 °C to 50 °C) with a sensitivity between 0.6% °C−1 and 1.2% °C−1 over this range. The last proposed method is the study of the lifetime variation versus temperature. The effective lifetime value corresponds to a combination of transitions from two excited energy levels of the tetravalent manganese (2E and 4T2) in thermal equilibrium toward the fundamental 4A2 state. Since the more energetic transition (4T2 → 4A2) is spin-allowed, contrary to the 2E → 4A2 one, the lifetime drastically decreases with the increase in temperature leading to an impressive high sensitivity value of 4.1% °C−1 at 4 °C and an exceptional temperature resolution of 0.025 °C. According to their optical features, MgTiO3:Mn4+ nanoparticles are indeed suitable candidates for the luminescence temperature probes at the nanoscale over several temperature ranges.
Herein, we demonstrate the photoluminescence properties of Dy
3+
-activated YNbO
4
, LuNbO
4,
and mixed Y
x
Lu
1−
x
NbO
4
:Dy
3+
(
x
= 0.25, 0.5, 0.75) phosphors. For this purpose, five samples ...with a fixed Dy
3+
concentration (2 mol%) were prepared by the solid-state reaction method. X-ray diffraction measurements showed that all phosphors crystallize in a monoclinic fergusonite-beta-(Y) structure with a C2/c space group. Scanning electron microscopy clearly shows that samples are composed of dense, well-developed micron-sized, cube-shaped grains with rounded edges. The photoluminescent emission spectra feature Dy
3+
peaks at standard positions corresponding to transitions from the
4
F
9/2
excited emitting level to the
6
H
J
(
J
= 15/2; 13/2; 11/2 and 9/2) lower levels with two dominant emission bands placed in the blue (~ 479 nm, B) and yellow (~ 576 nm, Y) spectral region. It is observed that with Lu increase in the host lattice Y/B ratio decreases toward the desired ratio of unity to obtain white light. To evaluate the suitability of these phosphors for use in solid-state lighting, their photoluminescence emission was analyzed in detail by calculating CIE coordinates, correlated color temperature (CCT) and Delta u,v (DUV). It is shown that CIE chromaticity coordinates of all Dy
3+
-activated Y
x
Lu
1−
x
NbO
4
samples (
x
= 0, 0.25, 0.5, 0.75, and 1) fall into the white portion of the diagram and that with the increase of Lu in the host lattice color becomes whiter. CCT values for all samples are in the cooler 4000–4500 K range with positive DUVs indicating that color points are placed above the black body curve. The average lifetime of
4
F
9/2
level is calculated to be ~ 0.2 ms for all Dy
3+
-activated Y
x
Lu
1−x
NbO
4
samples, indicating that there is no influence of the Y-to-Lu ratio in the host niobate material on the luminescence kinetics.
The aim of this study was to evaluate element (sodium, magnesium, potassium, calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, cadmium, and lead) deposition in honey bees (
...Apis mellifera
L.) (worker bees, drone bees, and bee broods) and their products (wax and multifloral honey) in the central and north parts of Serbia using inductively coupled plasma mass spectrometry (ICP-MS). The study was carried out during the spring and summer seasons when the honeybees were active (2019). Fifty-four colonies of honey bees from different apiaries (located in Rudnik, Lazarevac, and Ležimir) were used in this study. Significant differences in element concentrations were found among locations (
P
< 0.05). The highest deposition of elements (sodium, calcium, manganese, iron, cobalt, nickel, zinc, arsenic, and cadmium) was found in worker bees. The most commonly detected elements in wax were chromium and lead. Mg had a significant (
P
< 0.01) correlation with K, Fe, Cu, and As. This study shows that honey bees (worker bees, drone bees, and bee broods) could be more useful as bioindicators of environmental element deposition (toxic and non-toxic) than multifloral honey. Also, this study shows that Serbian multifloral honey meets safety criteria concerning the concentrations of toxic elements.
In this work, the potential of Li1.8Na0.2TiO3:Mn4+ for the lifetime-based luminescence thermometry is assessed. The material is prepared by the solid-state reaction of Li2CO3, Na2CO3, and ...nanostructured TiO2 at 800 °C, and its monoclinic structure (space group C2/c) is confirmed by X-ray diffraction analysis. In this host, Mn4+ provides strong absorption around 330 nm and 500 nm due to 4A2g → 4T1g and 4A2g→ 4T2g electric dipole forbidden and spin-allowed electron transitions, respectively, and emits around 679 nm on account of 2Eg→4A2g spin forbidden electron transition. Temperature dependences of emission intensity and emission decay are measured over the 10–350 K range. Due to the low value of energy of 4T2g level (20000 cm−1), the strong emission quenching starts at low-temperatures which favors the use of this material for the luminescence thermometry. It is demonstrated that the quite large value of relative sensitivity (2.27% K−1@330 K) facilitates temperature measurements with temperature resolution better than 0.15 K, and with the excellent repeatability.
•Li1.8Na0.2TiO3:Mn4+ was synthesized by the solid-state reaction method in C2/c structure.•The material was used as a probe for the lifetime-based luminescence thermometry.•Mn4+ emits around 679 nm due to of 2Eg→4A2g spin forbidden electron transition.•The material exhibits a large value of relative sensitivity (2.27% K−1@330 K).•Excellent Mn4+ emission repeatability with temperature resolution of 0.15 K.
The effect of Juniperus communis L. essential oil (JEO) addition at concentrations of 0.01, 0.05 and 0.10 µL/g on pH, instrumental parameters of color, lipid oxidation (2-Thiobarbituric acid reactive ...substances (TBARS)), microbial growth, texture and sensory attributes of dry fermented sausages produced with different levels of fat (15 and 25%) and sodium nitrite (0, 75 and 150 mg/kg) was assessed. Reduced level of sodium nitrite (75 mg/kg) in combination with all three concentrations of JEO (0.01–0.10 µL/g) resulted in satisfying physico-chemical (color and texture) properties and improved oxidative stability (TBARS < 0.3 mg MDA/kg) of dry fermented sausages produced with 25% of fat. However, sausages produced with 0.10 µL/g of JEO had untypical flavor. No foodborne pathogens (Escherichia coli, Listeria monocytogenes, Salmonella spp. and sulfite-reducing clostridia) were detected in any sample throughout the storage period (225 days). The results of this study revealed significant antioxidative activity of JEO and consequently its high potential as effective partial replacement for sodium nitrite in dry fermented sausages.
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