LED-Induced Fluorescence System for Tea Classification and Quality Assessment

A fluorescence system is developed by using several light emitting diodes (LEDs) with different wavelengths as excitation light sources. The fluorescence detection head consists of multi LED light sources and a multimode fiber for fluorescence collection, where the LEDs and the corresponding filters can be easily chosen to get appropriate excitation wavelengths for different applications. By analyzing fluorescence spectra with the principal component analysis method, the system is utilized in the classification of four types of green tea beverages and two types of black tea beverages. Qualities of the Xihu Longjing tea leaves of different grades, as well as the corresponding liquid tea samples, are studied to further investigate the ability and application of the system in the evaluation of classification/quality of tea and other foods

Poly[[aqua­bis(μ3-isonicotinato-κ3 O:O′:N)tris­(μ2-isonicotinato-κ3 O,O′:N)(nitrato-κO)bis­(μ4-oxalato-κ6 O 1,O 2:O 2:O 1′,O 2′:O 1′)dierbium(III)tetra­silver(I)] tetra­hydrate]

In the title coordination polymer, {[Ag4Er2(C6H4NO2)5(C2O4)2(NO3)(H2O)]·4H2O}n, each ErIII atom is coordinated in a bicapped trigonal–prismatic coordination geometry by three O atoms from two isonicotinate (IN) ligands, four O atoms from two oxalate ligands and one O atom from either a nitrate ion or a water mol­ecule, both of which are half-occupied over the same site. One AgI atom has a Y-shaped geometry defined by one N atom from one IN ligand, one O atom from another IN ligand and one O atom from an oxalate ligand. The other AgI atom is coordinated by two IN ligands and one O atom from an oxalate ligand. One of the IN ligands is disordered over an inversion center and forms a bridge between two centrosymmetric AgI ions. Due to the disorder, this IN ligand coordinates to the Ag atom through either the pyridyl N or the carboxyl­ate O atoms. The IN and oxalate ligands link the Er and Ag atoms into a three-dimensional coordination framework. O—H⋯O and C—H⋯O hydrogen bonds are observed in the crystal structure

Tetra­aqua­bis(5-hydroxy­nicotinato-κN)cadmium(II)

The title compound, [Cd(C6H4NO3)2(H2O)4], was obtained by the reaction of cadmium chloride with 5-hydroxy­nicotinic acid. The CdII atom is located on an inversion centre and is coordinated by two N atoms from two 5-hydroxy­nicotinic acid ligands and four water mol­ecules in a distorted octa­hedral geometry. The structure is stabilized by inter­molecular O—H⋯O hydrogen bonds, forming a three-dimensional network

Bis(μ-5-carboxyl­ato-1-carboxyl­ato­methyl-2-oxidopyridinium)-κ2 O 5:O 1;κ2 O 1:O 5-[diaqua­(phenan­throline-κ2 N,N′)manganese(II)] dihydrate

The centrosymmetric binuclear title complex, [Mn2(C8H5NO5)2(C12H8N2)2(H2O)4]·2H2O, was obtained by the reaction of manganese chloride with 5-carb­oxy-1-carboxy­methyl-2-oxidopyridinium and 1,10-phenanthroline. The MnII atom is coordinated by two N atoms from the 1,10-phenanthroline ligand, two O atoms from two 5-carboxyl­ato-1-carboxyl­atomethyl-2-oxidopyridinium ligands and two water mol­ecules, leading to a distorted octahedral MnN2O4 environment. Inter­molecular O—H⋯O hydrogen bonds link neighbouring mol­ecules into a layer structure parallel to (001)

15α,20β-Dihydr­oxy-6β-meth­oxy-6,7-seco-6,20-ep­oxy-1,7-olide-ent-kaur-16-ene

The title compound, C21H30O6, a natural ent-kaurane diterpenoid, was obtained from the medicinal plant Isodon serra. The five rings in the mol­ecule exhibit the expected cis and trans junctions. The three six-membered rings adopt chair, twist-boat and boat conformations, while two five-membered rings adopt envelope conformations. There are two mol­ecules in the asymmetric unit, related by a non-crystallographic twofold screw axis; the main difference is in the different degrees of distortion of ring B. In the crystal, the mol­ecules are linked by inter­molecular O—H⋯O hydrogen bonds, forming chains along the b axis

Mechanism underlying synergic activation of Tyrosinase promoter by MITF and IRF4

Background: The transcription factor interferon regulatory factor 4 (IRF4) was identified to be involved in human pigmentation by genome-wide association studies (GWASs). The rs12203592-[T/C], which is located in intron 4 of IRF4, shows the strongest link to these pigmentation phenotypes including freckling, sun sensitivity, eye and hair color. Previous studies indicated a functional cooperation of IRF4 with Microphthalmia-associated transcription factor (MITF), a causing gene of Waardenburg syndrome (WS), to synergistically trans-activate Tyrosinase (TYR). However, the underlying mechanism is still unknown. Methods: To investigate the importance of DNA binding in the synergic effect of IRF4. Reporter plasmids with mutant TYR promoters was generated to locate the IRF4 DNA binding sites in the Tyrosinase minimal promoter. By building MITF and IRF4 truncated mutations plasmids, the necessary regions of the synergy functions of these two proteins were also located. Results: The cooperative effect between MITF and IRF4 was specific for TYR promoter. The DNA-binding of IRF4 was critical for the synergic function. IRF4 DNA binding sites in TYR promoter were identified. The Trans-activation domains in IRF4 (aa134-207, aa300-420) were both important for the synergic function, whereas the auto-mask domain (aa207-300) appeared to mask the synergic effect. Mutational analysis in MITF indicated that both DNA-binding and transcriptional activation domains were both required for this synergic effect. Conclusions: Here we showed that IRF4 potently synergized with MITF to activate the TYR promoter, which was dependent on DNA binding of IRF4. The synergic domains in both IRF4 and MITF were identified by mutational analysis. This identification of IRF4 as a partner for MITF in regulation of TYR may provide an important molecular function for IRF4 in the genesis of melanocytes and the pathogenic mechanism in WS