Recently, the term premenstrual disorders (PMDs), which includes premenstrual syndrome and premenstrual dysphoric disorder as a continuum, has been proposed. Although the precise etiology of PMDs ...remains unknown, the involvement of hormonal fluctuations is clear. The brain transmitters, serotonin and γ‐amino butyric acid, also seem to be involved. Serotonin reuptake inhibitors and oral contraceptives are the current mainstay of treatment, but these are insufficient. Even the currently used prospective two‐period symptom diary is not widely used in actual clinical practice, creating a major problem of discrepancy between research and clinical practice. In this review, I would like to outline the latest information and problems in the etiology, diagnosis, and treatment of PMDs, with an emphasis on promising new therapies.
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Advances in solid state white lighting technologies witness the explosive development of phosphor materials (down-conversion luminescent materials). A large amount of evidence has demonstrated the ...revolutionary role of the emerging nitride phosphors in producing superior white light-emitting diodes for lighting and display applications. The structural and compositional versatility together with the unique local coordination environments enable nitride materials to have compelling luminescent properties such as abundant emission colors, controllable photoluminescence spectra, high conversion efficiency, and small thermal quenching/degradation. Here, we summarize the state-of-art progress on this novel family of luminescent materials and discuss the topics of materials discovery, crystal chemistry, structure-related luminescence, temperature-dependent luminescence, and spectral tailoring. We also overview different types of nitride phosphors and their applications in solid state lighting, including general illumination, backlighting, and laser-driven lighting. Finally, the challenges and outlooks in this type of promising down-conversion materials are highlighted.
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The polypeptide chain is an important structural unit that forms the secondary structure of proteins
via
intermolecular amide-type N-H O&z.dbd; hydrogen bonds. In contrast, alkylamide chains (-CONHC
...n
H
2
n
+1
) are interesting structural units in which an amide group with a dipole moment and an alkyl chain with high conformational freedom coexist, which have been used to form characteristic molecular assembly structures such as liquid crystals, gels, and supramolecular polymers. One-dimensional chains based on intermolecular N-H O&z.dbd; hydrogen-bonding interaction form these molecular assemblies. In the liquid crystal, an electric field - polarization hysteresis curve was observed for alkylamide-substituted benzene derivatives. A molecular design based on the combination of the alkylamide chain, which is the origin of ferroelectricity, and the functional π-electron framework enables the coexistence of ferroelectricity with luminescence, high thermal stability, photoresponse, and current switching properties, and the fabrication of multifunctional molecular materials. The introduction of chiral alkylamide chains is also effective in controlling unidirectional dipole inversion and low coercive electric fields for low-energy-consumption memory devices. Alkylamide chains in molecular assemblies are useful for the development and control of the physical properties of organic ferroelectrics that realize the rotational dynamics of polar amide groups coupled with the melting of alkyl chains in the liquid crystal and solid states.
The polypeptide chain is an important structural unit that forms the secondary structure of proteins
via
intermolecular amide-type N-H O&z.dbd; hydrogen bonds.
Dynamic molecular processes, such as short- or long-range proton (H
+
) and ion (M
+
) motions, and molecular rotations in electrical conducting and magnetic molecular assemblies enable the ...fabrication of electron-H
+
(or M
+
) coupling systems, while crystal lattice dynamics and molecular conformation changes in hydrogen-bonded molecular crystals have been utilised in external stimuli responsive reversible gas-induced gate opening and molecular adsorption/desorption behavior. These dynamics of the polar structural units are responsible for the dielectric measurements. The H
+
dynamics are formed from ferroelectrics and H
+
conductors, while the dynamic M
+
motions of Li
+
and Na
+
involve ionic conductors and coupling to the conduction electrons. In n-type organic semiconductors, the crystal lattices are modulated by replacing M
+
cations, with cations such as Li
+
, Na
+
, K
+
, Rb
+
, and Cs
+
. The use of polar rotator or inversion structures such as alkyl amides,
m
-fluoroanilinium cations, and bowl-shaped trithiasumanene π-cores enables the formation of ferroelectric molecular assemblies. The host-guest molecular systems of ESIPT fluorescent chromic molecules showed interesting molecular sensing properties using various bases, where the dynamic transformation of the crystal lattice and the molecular conformational change were coupled to each other.
Dynamic processes such as proton, ion, and molecular rotations enable the fabrication of multifunctional molecular assemblies, while crystal lattice dynamics and molecular conformation changes have been utilised in external stimuli responsive hydrogen-bonding crystals.
Drastic changes in the optical and electronic properties of arylsulfonamide-substituted anthraquinones were induced by simple
N
-methylation.
N
-Methylation at the congested
peri
-position of the ...anthraquinone unit induced a drastic conformational change from a coplanar arrangement to an orthogonal relationship between the anthraquinone scaffold and arylsulfonamide substituents. As a result, the contribution of the substituents on the anthraquinone unit was spectroscopically suppressed, as demonstrated by UV-Vis absorption spectra and cyclic voltammograms.
Simple
N
-methylation induced dynamic structural change of arylsulfonamide-substituted anthraquinone, which induced drastic change in optical and electronic properties.
Deep-trap persistent luminescence materials exhibit unique properties of energy storage and controllable photon release under additional stimulation, allowing for both wavelength and intensity ...multiplexing to realize high-capacity storage in the next-generation information storage system. However, the lack of suitable persistent luminescence materials with deep traps is the bottleneck of such storage technologies. In this study, we successfully developed a series of novel deep-trap persistent luminescence materials in the Ln2+/Ln3+-doped SrSi2O2N2 system (Ln2+ = Yb, Eu; Ln3+ = Dy, Ho, Er) by applying the strategy of trap depth engineering. Interestingly, the trap depth can be tailored by selecting different codopants, and it monotonically increases from 0.90 to 1.18 eV in the order of Er, Ho, and Dy. This is well explained by the energy levels indicated in the host-referred binding energy scheme. The orange-red-emitting SrSi2O2N2:Yb,Dy and green-emitting SrSi2O2N2:Eu,Dy phosphors are demonstrated to be good candidates of information storage materials, which are attributed to their deep traps, narrow thermoluminescence glow bands, high emission efficiency, and excellent chemical stability. This work not only validates the suitability of deep-trap persistent luminescence materials in the information storage applications, but also broadens the avenue to explore such kinds of new materials for applications in anticounterfeiting and advanced displays.
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We prepared octylbenzoate-substituted 12DBA (
C812DBA
) as an organic molecular glass material. Even with a central large, planar π unit of 12DBA, which is generally advantageous for the formation of ...a crystalline/liquid crystalline state, this compound formed a thermally stable glass state due to its small intermolecular π contact between 12DBA units and twisted geometries around the terminal benzoate units.
C812DBA
showed a unique dielectric anomaly and isolated fluorescence properties in the glass state.
We prepared an organic molecular glass material with a large central planar π unit, which showed a unique dielectric anomaly and isolated fluorescence properties.
As a next-generation high-power lighting technology, laser lighting has attracted great attention in high-luminance applications. However, thermally robust and highly efficient color converters ...suitable for high-quality laser lighting are scarce. Despite its versatility, the phosphor-in-glass (PiG) has been seldom applied in laser lighting because of its low thermal conductivity. In this work, we develop a unique architecture in which a phosphor-in-glass (PiG) film was directly sintered on a high thermally conductive sapphire substrate coated by one-dimensional photonic crystals. The designed color converter with the composite architecture exhibits a high internal quantum efficiency close to that of the original phosphor powders and an excellent packaging efficiency up to 90%. Furthermore, the PiG film can even be survived under the 11.2 W mm–2 blue laser excitation. Combining blue laser diodes with the YAG-PiG-on-sapphire plate, a uniform white light with a high luminance of 845 Mcd m–2(luminous flux: 1839 lm), luminous efficacy of 210 lm W–1, and correlated color temperature of 6504 K was obtained. A high color rendering index of 74 was attained by adding a robust orange or red phosphor layer to the architecture. These outstanding properties meet the standards of vehicle regulations, enabling the PiG films with the composite architecture to be applied in automotive lighting or other high-power and high-luminance laser lighting.
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5‑Fluorobenzoyl-4-(4-methoxyphenyl)ethynyl-1-methylimidazole 1 exhibited a thermosalient effect without phase transition. The crystal of 1 was jumped by heating to about 80 °C using a hot plate. No ...phase transition peak was observed at this temperature range according to DSC measurement, unlike renowned thermosalient crystals. Variable-temperature X-ray crystal structure analyses revealed that anisotropical cell constant expansion resulting from the torsion angle change between the imidazole group and carbonyl moiety induced unit cell constant expansion and the thermosalient effect.
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Discovery of novel luminescent materials is of fundamental importance in the advancement of solid state lighting and flat panel display technologies. In this work, we report a ...single-particle-diagnosis method for the discovery of new phosphors by just characterizing a luminescent crystalline particle as small as 10 μm in diameter. We explored single-particle fluorescence imaging and spectroscopy techniques to evaluate the photoluminescence of a phosphor particle distinguished from a complex powder mixture and applied a high-resolution single-crystal X-ray diffractometer to determine its crystal structure. The approach enabled us to discover two new phosphors in the Ba3N2–Si3N4–AlN ternary system: Ba5Si11Al7N25:Eu2+ and BaSi4Al3N9:Eu2+. Ba5Si11Al7N25:Eu2+ crystallizes in the space group of Pnnm (no. 58) with a = 9.5923(2), b = 21.3991(5), c = 5.8889 (2) Å and Z = 2, while BaSi4Al3N9:Eu2+ in the space group of P21/C (no.14) with a = 5.8465(4), b = 26.7255(18), c = 5.8386(4) Å, β = 118.897° and Z = 4. The single-particle photoluminescence of Ba5Si11Al7N25:Eu2+ shows yellow emission (λem = 568 nm, fwhm = 98 nm) and a quantum efficiency of 36% under the 405 nm excitation. BaSi4Al3N9:Eu2+ shows blue emission (λem = 500 nm, fwhm = 67 nm) upon the 365 nm excitation.
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