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The fractional oxidation state [M(dmit)2] (dmit2- = 2-thioxo-1, 3-dithiole-4, 5-dithiolate) salts have long attracted attention in the molecular metal area owing to high conductivity and even superconductivity. In this study, we achieved a mixed-valence salt (1) of [Ni(dmit)2]0.5- with monovalent 1,3-N,N-dimethyl-imidazolium (DiMIm+) by a solvent evaporation approach under ambient conditions. The mixed valence of [Ni(dmit)2]0.5- has been characterized by an analysis of the IR spectrum and crystal structure. In the crystal structure of 1, two [Ni(dmit)2]0.5- anions overlap in an eclipsed mode to form a [Ni(dmit)2]21- dimer, featuring a radical bearing an S = 1/2 spin; the dimeric radicals stack into a column along the b axis, and the adjacent columns connect together via the lateral-to-lateral S···S contacts along the a axis, and through the head-to-head S···S contacts along the [101] direction. Salt 1 shows the magnetic behavior of an S = 1/2 Heisenberg antiferromagnetic uniform linear chain with J/kB = -47.5(4) K and a semiconducting feature with σ = 2.52 × 10-3 S cm-1 at 293 K, 2.32 × 10-2 S cm-1 at 373 K, and Ea = 0.22 eV, as well as broadband photoconductivity under irradiation of green and white lights. This study suggests the possibility of designing new photoconductors based on the mixed-valence [Ni(dmit)2]0.5- salt.
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In this study, we used the facile solvent evaporation method to achieve the inorganic-organic hybrid crystals of [triethylpropylammonium][PbI3], which have been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and differential scanning calorimetry as well as single-crystal X-ray structure analysis. The hybrid solid crystallizes in the monoclinic space group P21/c at room temperature and is composed of one-dimensional [PbI3]∞ chains, where the neighboring PbI6 coordination octahedra connect together via the face-sharing mode and the organic cations fall in the spaces between [PbI3]∞ chains. The hybrid exhibits a dielectric phase transition with a critical temperature of ca. 432 K, dielectric relaxation at frequencies below 107 Hz, and single-ion conducting behavior, the conductivity of which increases rapidly from 9.43 × 10-10 S cm-1 at 383 K to 4.47 × 10-5 S cm-1 at 473 K. The variable-temperature single-crystal and powder X-ray diffraction analyses revealed that the dielectric phase transition is related to the disorder-to-order transformation of cations in the lattice. The electric modulus and impedance spectral analyses further disclosed that the dielectric relaxation arises from the ionic displacement polarization and molecular dipole orientation of cations. The single-ion conductance is due to the migration of cations that fall in the spaces of rigid inorganic [PbI3]∞ chains. The phase transition gives rise to this hybrid showing switchable ion-conducting nature around the critical temperature of the phase transition. Besides the fascinating functionalities mentioned above, the hybrid also exhibits a thermochromic luminescence feature originating from the electron transition between the valence and conduction bands of the inorganic [PbI3]∞ chain.
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UVA1 phototherapy, a new therapeutic approach, has recently been shown good efficacy in the treatment of palmoplantar pustulosis (PPP). The purpose of this study was to compare the efficacy of UVA1 and narrowband UVB (NB-UVB) therapy in the treatment of PPP. Patients with PPP were randomly assigned to either UVA1 or NB-UVB therapy according to a left-right randomization table. Both treatments were performed three times weekly for up to 30 sessions. Clinical evaluation was based on the Palmoplantar Pustular Psoriasis Area and Severity Index (PPPASI) score. Totally 64 patients completed the study. Both UVA1 and NB-UVB therapy showed a statistically significant reduction of PPPASI score compared with the baseline value at the end of the treatment period (P < 0.05). There was a significantly greater mean reduction of PPPASI score in the UVA1 treated group when compared to the NB-UVB treated patients at 30 sessions (6.0 ± 2.4 vs. 4.4 ± 1.4, P < 0.05). No phototoxic reaction or bullous changes were observed in either group. Both NB-UVB and UVA1 phototherapy of PPP resulted in significant improvement. UVA1 phototherapy was more effective than NB-UVB irradiation in the treatment of PPP.
Assuntos
Psoríase/radioterapia , Terapia Ultravioleta/métodos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Resultado do Tratamento , Raios UltravioletaRESUMO
A Zn-based metal-organic framework (MOF)/porous coordination polymer (PCP), (EMIM)[Zn(SIP)] (1) (SIP3- = 5-sulfoisophthalate, EMIM+ = 1-ethyl-3-methylimidazolium), was synthesized using the ionothermal reaction. The Zn2+ ion adopts distorted square pyramid coordination geometry with five oxygen atoms from three carboxylates and one sulfo group. One of two carboxylates in SIP3- serves as a µ2-bridge ligand to link two Zn2+ ions and form the dinuclear SBU, and such SBUs are connected by SIP3- ligands to build the three-dimensional framework with rutile (rtl) topology. The cations from the ion-liquid fill the channels. This MOF/PCP shows two-step dielectric anomalies together with two-step dielectric relaxations; the variable-temperature single-crystal structure analyses disclosed the dielectric anomaly occurring at ca. 280 K is caused by an isostructural phase transition. Another dielectric anomaly is related to the dynamic disorder of the cations in the channels. Electric modulus, conductance, and variable-temperature solid-state 13C CP/MAS NMR spectra analyses revealed that two-step dielectric relaxations result from the dynamic motion of the cations as well as the direct-current conduction and electrode effect, respectively.
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Vitiligo is an acquired pigmentary disorder characterized by loss of epidermal melanocytes. A strong association at a single nucleotide polymorphism (SNP) rs11966200 within MHC region had been identified in a recent genome-wide association study of generalized vitiligo in Chinese Han population. This study aims to investigate the relationships between SNP rs11966200 and the clinical features of generalized vitiligo in Chinese Han population. We compared the allele and genotype frequency among different vitiligo subphenotypes including age onset, extent of disease, clinical subtypes, family history of vitiligo and history of autoimmune disease. Our data showed SNP rs11966200 was associated with early-onset vitiligo (onset age ≤ 20 years) (odds ratio [OR], 1.54; p = 2.01 × 10(-13)), moderate-severe vitiligo (involved body surface ≥ 5 %) (OR, 1.17; p = 0.025), vitiligo vulgaris (OR, 1.13; p = 0.043), and focal vitiligo (OR, 0.86; p = 0.018). The study suggested that the underlying risk causal allele tagged by SNP rs11966200 might not only play important roles in the development of vitiligo, but also contribute to the diverse clinical characteristics of generalized vitiligo at least in Chinese Han population.
Assuntos
Povo Asiático/genética , Etnicidade/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Complexo Principal de Histocompatibilidade/genética , Polimorfismo de Nucleotídeo Único/genética , Vitiligo/genética , Adulto , Idade de Início , Alelos , Estudos de Casos e Controles , China , Feminino , Técnicas de Genotipagem , Humanos , Masculino , Fenótipo , Vitiligo/classificaçãoRESUMO
In the anion of the title compound, (C12H13N2)[Ni(C4N2S2)2], the Ni(II) atom is coordinated by four S atoms from two 1,2-di-cyano-ethene-1,2-di-thiol-ate (mnt) ligands in a suqare-planar geometry. Weak C-Hâ¯N and C-Hâ¯S hydrogen bonds between the 1-ethyl-4,4'-bipyridin-1-ium cations and mnt anions and weak π-π inter-actions between the pyridine rings of the cations [centroid-centroid distances = 3.808â (3) and 3.972â (3)â Å] lead to a two-dimensional network parallel to (010).
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The title complex, {[Co2(C18H4O10)(C14H14N4)2]·2H2O} n was synthesized from CoCl2·6H2O, 9,10-dioxo-9,10-dihydro-anthracene-1,4,5,8-tetra-carb-oxy-lic acid (H4AQTC) and 1,2-bis-[(1H-imidazol-1-yl)meth-yl]benzene (o-bix) in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one Co(II) atom and one o-bix ligand, as well as half an AQTC(4-) ligand and an additional solvent water mol-ecule. The Co(II) ions are tetra-hedrally surrounded by two O atoms from two AQTC(4-) anions and by two N atoms from two o-bix ligands, forming a two-dimensional coordination polymer. The solvent water mol-ecules are connected to the carboxyl-ate groups by O-Hâ¯O hydrogen bonds. Additional weak C-Hâ¯O hydrogen bonds are observed in the crystal structure.
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The title complex, [Mn(2)(C(18)H(4)O(10))(H(2)O)(4)](n), was synthesized from manganese(II) chloride tetra-hydrate and 9,10-dioxo-9,10-dihydro-anthracene-1,4,5,8-tetra-carb-oxy-lic acid (H(4)AQTC) in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one Mn(II) atom, two water ligands and one half AQTC(4-) anion. The Mn(II) atom is coordinated in a distorted octa-hedral geometry by four O atoms from three AQTC(4-) ligands and two water O atoms. Two of the carboxyl-ate groups coordinate one Mn(II) atom in a chelating mode, whereas the others each coordinate two Mn(II) atoms. Each AQTC(4-) tetra-anion therefore coordinates six different Mn(II) ions and, as a result, a three-dimensional coordination polymer is formed. O-Hâ¯O hydrogen bonds, some of them bifurcated, between water ligands and neighboring water or anthraquinone ligands are observed in the crystal structure.
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Senescence is an inevitable natural life process that involves structural and functional degeneration of tissues and organs. Recently, the process of skin aging has attracted much attention. Determining a means to delay or even reverse skin aging has become a research hotspot in medical cosmetology and anti-aging. Dysfunction in the epidermis and fibroblasts and changes in the composition and content of the extracellular matrix are common pathophysiological manifestations of skin aging. Reactive oxygen species and matrix metalloproteinases play essential roles in this process. Stem cells are pluripotent cells that possess self-replication abilities and can differentiate into multiple functional cells under certain conditions. These cells also possess a strong ability to facilitate tissue repair and regeneration. Stem cell transplantation has the potential for application in anti-aging therapy. Increasing studies have demonstrated that stem cells perform functions through paracrine processes, particularly those involving exosomes. Exosomes are nano-vesicular substances secreted by stem cells that participate in cell-to-cell communication by transporting their contents into target cells. In this chapter, the biological characteristics of exosomes were reviewed, including their effects on extracellular matrix formation, epidermal cell function, fibroblast function and antioxidation. Exosomes derived from stem cells may provide a new means to reverse skin aging.
Assuntos
Exossomos , Envelhecimento da Pele , Fibroblastos , Espécies Reativas de Oxigênio , Células-TroncoRESUMO
The asymmetric unit of the title compound, [Co(C(9)H(7)O(4))(2)(C(12)H(10)N(2))(2)(H(2)O)(2)], consists of one Co(2+) ion, one mono-deprotonated 2-(4-carboxyl-atophen-yl)acetate carboxylic acid, one 1,2-bis-(pyridin-4-yl)ethane mol-ecule and one water mol-ecule. The Co(II) atom is situated on a crystallographic center of inversion and is octa-hedrally coordinated by two O atoms from two anions, two N atoms of two 1,2-bis-(pyridin-4-yl)ethane mol-ecules and two O atoms from two water mol-ecules. A three-dimensional network is established by inter-molecular O-Hâ¯O and O-Hâ¯N hydrogen bonds.
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Herein we report the first example of the proton conductivity of an open-framework metal phosphate (NH3(CH2)3NH3)2-[Fe4(OH)3(HPO4)2(PO4)3]·4H2O under aqua-ammonia vapor. Its optimized proton conductivity is 5 × 10-2 S cm-1 at 313 K and aqua-ammonium vapor from 1 M NH3·H2O solution. That is approximately two orders of magnitude greater than the maximum value under water vapor (8.0 × 10-4 S cm-1 at 317 K and 99% RH). The proton transfer mechanism has been proposed in terms of the structural analyses, activation energy calculations, and PXRD determinations.
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The tetra-nuclear copper(II) title complex, [Cu(4)Cl(2)(OH)(4)(C(10)H(8)N(2))(4)](NO(3))(2)·6H(2)O, has a crystallographically imposed centre of symmetry. The metal atoms display a distorted tetragonal-pyramidal coordination geometry, and are linked by two µ(2)- and two µ(3)-hydroxo groups, assuming a chair-like conformation for the Cu(4)O(2) core. In the crystal, the complex mol-ecules are linked into a three-dimensional network by inter-molecular O-Hâ¯O, O-Hâ¯Cl, C-Hâ¯O and C-Hâ¯Cl hydrogen bonds and π-π stacking inter-actions with centroid-centroid separations of 3.724â (2) and 3.767â (3)â Å.
RESUMO
The asymmetric unit of the title compound, (C(13)H(11)Cl(2)N(2))(2)[Ni(C(4)N(2)S(2))(2)], contains one-half of a centrosymmetric [Ni(mnt)(2)] anion (where mnt is maleonitrile-dithiol-ate or 1,2-dicyano-1,2-ethyl-enedithiol-ate) and an (E)-1-(3,4-dichloro-benzyl-ideneamino)-4-methyl-pyridinium cation. In the anion, the coordination around the Ni atom is a distorted square. In the cation, the aromatic rings are oriented at a dihedral angle of 7.81â (3)°. In the crystal structure, inter-molecular C-Hâ¯N hydrogen bonds link the cations and anions. π-π Contacts between the nickel dithiol-ene and pyridine rings and between the benzene and pyridine rings, [centroid-centroid distances = 3.682â (3) and 3.643â (3)â Å, respectively] may further stabilize the structure.
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In the title salt, C(4)H(8)N(5) (+)·NO(3) (-), a ring N atom of 2,6-diamino-4-methyl-triazine is protonated. Each anion is connected to three neighbouring cations by multiple N-Hâ¯O hydrogen bonds which, together with N-Hâ¯N contacts, generate a layer structure.
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New luminescent Pb(ii)-coordination polymers (Pb(ii)-CPs), [Pb(2-anc)2]n (1) and [Pb(3-qlc)2(H2O)2]n (2) (2-anc = 2-aminonicotinate, 3-qlc = 3-quinolinecarboxylate), were synthesized by a solvothermal reaction and characterized using microanalysis, IR spectrometry and thermogravimetric analysis. Single crystal structure analysis revealed that the Pb2+ ion displays a hemi-directed coordination geometry in 1 and a holo-directed coordination geometry in 2. The difference between the coordination spheres of 1 and 2 is related to the steric hindrance effect of the ligands. A two-dimensional (2D) corrugated layer structure is formed in 1, and the neighboring layers are further extended into a three-dimensional (3D) van der Waals crystal by ππ interactions between the pyridyl rings in the neighboring layers. In contrast, a one-dimensional (1D) coordination polymeric chain is formed in 2, and the adjacent chains are connected in a 2D network by hydrogen bonds. The photophysical properties of 1 and 2 were studied at ambient conditions, disclosing that 1 emits phosphorescence at 548 nm with a millisecond-scale emission lifetime and an absolute quantum yield of 2.2%; 2 emits only blue fluorescence with an absolute quantum yield of 3.5% and nanosecond-scale emission lifetime. The reasons for the difference in the photophysical nature of 1 and 2 are discussed in regards to the electron band structure and density of states analysis.
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As a class of anionic oxoclusters of early transition metals in their highest oxidation states, polyoxometalates (POMs) show considerable structural versatility and unique chemical and physical properties, making them promising multifunctional materials. In this study, a Keggin-type POM has been achieved, with a formula of [(H2O)0.3@K6(H2O)12]H4.45[PV7.45Mo4.55O40]·11H2O (1), and its microcrystals and nanocrystals have been obtained, respectively. This POM was characterized by elemental analysis for C, H and N, ICP-MS, TG, PXRD, SEM, X-band EPR and XPS techniques. Single crystal X-ray diffraction analysis demonstrated that 1 shows a rare extended structure with a high-connected three-dimensional (3D) all inorganic network of a Keggin-type POM, built from {Mo4.55V7.45PO40}10.45- polyoxoanions and {(H2O)0.3@K6(H2O)12}6+ clusters with CsCl-type crystal structure. In addition, to the best of our knowledge, 1 shows the highest ratio of vanadium to molybdenum among Keggin-type POMs reported thus far. Most interestingly, 1 exhibits intrinsic proton conduction below the freezing point of water, with a proton conductivity of 6.90 × 10-7 S cm-1 at 249 K and further reaching 3.36 × 10-6 S cm-1 at 272 K and Ea = 0.44 eV at 249-272 K.
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The asymmetric unit of the title compound, (C(6)H(9)N(2))(2)[Ni(C(4)N(2)S(2))(2)], contains one half of an [Ni(mnt)(2)](2-) anion (mnt is maleonitrile-dithiol-ate or 1,2-dicyano-ethene-1,2-dithiol-ate) and one 1-amino-4-methyl-pyridinium cation. The Ni(II) atom is located on an inversion centre. In the crystal structure, inter-molecular N-Hâ¯N hydrogen bonds link the mol-ecules.
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The title compound, C(7)H(4)Br(2)O(2), exhibits a layer packing structure via weak π-π stacking inter-actions [centroid-centroid distances between adjacent aromatic rings are 4.040â (8) and 3.776â (7)â Å]. Mol-ecules in each layer are linked by inter-molecular O-Hâ¯O hydrogen bonding and Brâ¯Br inter-actions [3.772â (4)â Å]. There are two mol-ecules in the asymmetric unit.
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The title compound, C(7)H(4)Cl(2)O(2), exhibits a layer crystal structure; mol-ecules within each layer are linked by weak C-Hâ¯O inter-molecular hydrogen bonds. There is also an intramolecular O-Hâ¯O hydrogen bond.
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In the title compound, [Cu(C(7)H(3)Cl(2)O(2))(2)](n), the Cu(II) atom lies on a centre of inversion and adopts a [4+2] coordination mode, with two long axial Cu-Cl coordinative bonds complementing four Cu-O bonds from two 2,4-dichloro-6-formyl-phenolate ligands in a distorted square plane. π-π stacking inter-actions are also formed between neighbouring aromatic rings, with a centroid-centroid separation of 3.624â (2)â Å.