Ultraviolet Absorption Maximum Research Articles

Synthesis of near infrared absorbing cationic zinc aminophthalocyanine and its application as an efficient photo-sensitizing nanoparticle in anti-drug-resistant bacteria

The emergence of drug-resistant bacteria threatens human health, and photodynamic therapy and photothermal therapy are promising methods to eliminate drug-resistant bacteria. However, the key to photodynamic and photothermal therapy is efficient photosensitizers, which are not fully developed. Herein, a novel cationic zinc aminophthalocyanine, zinc tetrakis(dimethyloctylammonium bromide) phthalocyanine (DMAZnPc-C8), is synthesized and investigated. The structures of the cationic zinc aminophthalocyanines are characterized by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance hydrogen spectrum (1H NMR)，Mass spectrometry and X-ray spectroscopy. The singlet oxygen generation ability, photo-thermal properties and antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA) of cationic zinc aminophthalocyanine nanoparticles (DMAZnPc-C8 NP) in aqueous dispersion are investigated. The results show that the maximum ultraviolet absorption wavelength of DMAZnPc-C8 in DMSO is at 764 nm, and DMAZnPc-C8 shows good response to near-infrared light. DMAZnPc-C8 NP has good photo-thermal performance. After irradiation with an 808 nm laser (0.5 W/cm2) for 10 min, the temperature of DMAZnPc-C8 NP dispersion (0.05 mg/mL) is increased by 7.4 °C. And DMAZnPc-C8 NP has good singlet oxygen production capacity. DMAZnPc-C8 NP has excellent antibacterial effect against MRSA-resistant bacteria. When the concentration of DMAZnPc-C8 NP is 0.03 mg/mL, the growth of MRSA is almost completely inhibited after 10 min of laser irradiation at 808 nm (0.5 W/cm2), the antibacterial rate reach over 99 %. This study shows that cationic zinc aminophthalocyanine has promising application prospects in the field of anti-drug-resistant bacteria.

Preparing bright Monascus yellow pigments by loading quercetin-Sn(II)- albumin –chitosan: Enhanced stability and bioactivity

Natural Monascus yellow pigments (MYPs) have received considerable attention due to their great safety and biological activities, but their unsatisfactory color tonality and stability limit their applications. A novel encapsulate system for hydrophilic yellow pigments (HYPs) were investigated through stable ternary nanocomplexes using quercetin-Sn (II), bovine serum albumin (BSA), and chitosan (CS) in this work. Layer-by-layer assembly preparation of HYPs-loaded quercetin-Sn (II)-BSA-CS nanocomplexes were verified by fluorescence spectroscopy, fourier transform infrared spectroscopy, X-ray photoelectron spectra, and 1H nuclear magnetic resonance. A hyperchromic effect on HYPs was obtained since their maximum ultraviolet absorption wavelength redshifted from 352 nm to 364 nm first due to the interaction with quercetin-Sn (II) and further redshifted to 408 nm due to ternary conjugation, greatly improved the color tonality and dye-uptake. The HYPs-loaded nanocomplexes showed irregular glomerate nanosphere with 252–382 nm of particle size. Their conjugation remitted HYPs degradation under various environmental stresses (thermal, light, and ascorbic acid treatment), and had a great color stability response to pH change. Higher lipid-lowering and antioxidant activities were detected in the nanocomplexes than free HYPs. This study provides a new way for fabricating novel MYPs with great physicochemical stability, bright color and hypolipidemic activities.

High performance liquid chromatography three-wavelength fusion fingerprint combined with electrochemical fingerprint and antioxidant method to evaluate the quality consistency of Mingmu Dihuang Pill

In this paper, three-wavelength fusion fingerprint (TWFFP) combined with electrochemical fingerprint (ECFP) and antioxidant methods were used to jointly explore the quality consistency of Mingmu Dihuang Pill (MMDHP). The TWFFP fully demonstrated the maximum ultraviolet absorption characteristics at multiple wavelengths, supplemented the defects brought by the single-wavelength evaluation. ECFP was established to analyze the characteristic parameters in more depth, and all samples had inhibitory effects on the electrochemical oscillation system. Using 2,2-diaza-bis(3-ethylbenzothiazole-6-sulfonic acid) antioxidant test, combined with ECFP, the fingerprint-efficacy relationship was established with the peak areas of the TWFFP. As a result, 15 of the 36 common peaks made important contributions to both efficacy relationships at the same time. The TWFFP and ECFP were evaluated by a systematically quantified fingerprint method, and the ability of HPLC and electrochemical to distinguish samples was discussed by hierarchical clustering analysis. Content percentage was introduced to calculate the relationship between marker components and macro quantitative similarity. The method of quantitative analysis of multi-components by single marker was explored to analyze the accuracy of evaluating the marker components. This study provided a comprehensive and reliable method for the quality consistency control of complex Traditional Chinese Medicine and its compound preparations.

New Bithiophene Extended IDIC-Based Non-Fullerene Acceptors and Organic Photovoltaics Thereof.

We developed new bithiophene extended electron acceptors based on m-alkoxythenyl-substituted IDIC with three different end groups, named as IDT-BT-IC, IDT-BT-IC4F, and IDT-BT-IC4Cl, respectively. The ultraviolet absorption maximum was redshifted and the bandgap was decreased as the strong electron accepting ability of the end group increased. A differential scanning calorimetry thermogram analysis revealed that all the new acceptors have a crystalline character. Using these acceptors and a bulk heterojunction structure using PBDB-T, inverted organic photovoltaic (OPV) devices were fabricated, and their performance was analyzed. Due to the red shift of the electron acceptors, the OPV active layer particularly, which was derived from IDT-BT-IC4F, exhibited increased absorption at long wavelengths over 800 nm. The OPV prepared using IDT-BT-IC exhibited a short-circuit current density (Jsc) of 2.30 mA/cm2, an open-circuit voltage (Voc) of 0.95 V, a fill factor (FF) of 45%, and a photocurrent efficiency (PCE) of 1.00%. Using IDT-BT-IC4F, the corresponding OPV device showed Jsc = 8.31 mA/cm2, Voc = 0.86 V, FF = 47%, and PCE = 3.37%. The IDT-BT-IC4Cl-derived OPV had Jsc = 3.00 mA/cm2, Voc = 0.89 V, FF = 29%, and PCE = 0.76%. When IDT-BT-IC4F was used as the electron acceptor, the highest Jsc and PCE values were achieved. The results show that the low average roughness (0.263 nm) of the active layer improves the extraction of electrons.

Original boron cluster covalent with poly-zwitterionic BODIPYs for boron neutron capture therapy agent

Currently, boron neutron capture therapy（BNCT） is the most innovative and promising highly selective targeted radiotherapy for cancer. Therefore, this paper designed and synthesized two kinds of boron-polymers, wrapped in the same fluorophore -BODIPYs, as fluorescent targeting markers for rapid, accurate, real-time, and inexpensive detection of boron-containing drugs. The spherical polymer o-carborane (PBC) in different polar solvents, the ultraviolet maximum absorption wavelength is in the range of 530–545 nm. The maximum ultraviolet absorption wavelength of PBD is in the range of 440–520 nm. The fluorescence spectra of the two boron-polymer are very similar, and the maximum emission wavelength is concentrated in the range of 550–560 nm. In terms of cytotoxicity and in vitro cell imaging, the in vitro biological toxicity evaluation of the two boron-polymer reached the expected high level, especially the cytotoxic concentration of PBD reached 1.347 ± 0.033 μM, which was higher than the 2.829 ± 0.351 μM of PBC. By transmission electron microscopy, it was found that the two terminal zwitterions of BODIPY polymer tightly wrapped boron clusters to form small particle nanoclusters. The imaging of the two boron-polymers was tested in the Hera cell lines of low, medium, and high densities. The in vitro study results revealed high levels of accumulation in HeLa cells with higher cytotoxicity and boron uptake compared to L-boron-phenylalanine (BPA). In vivo imaging, large number of borane polymers were observed to accumulate in the subcutaneous tumor sites of mice over time, indicating that it has high selectivity and high aggregation.

A strong acid-resistant flavanthrone with excellent photophysical properties

Based on a vat dye of anthraquinone type, simple modification of the structure of flavanthrone (Benzo[h]Benz[5,6]Acridino[2,1,9,8-Klmna]Acridine-8,16-Dione). By introducing the electrochemically inert group 1-bromo-3,5-di-tert-butylbenzene after the reduction of the carbonyl group, increasing the probability of fluorescence transition. And discussed the new simple compound that under different strongly acidic conditions, the optical properties are obviously distinction. Sulfuric acid, methanesulfonic acid and hydrochloric acid were added, the maximum ultraviolet absorption wavelength of the original product is redshifted from 510 nm to about 590 nm, and the fluorescence emission wavelength is around 523 nm to 526 nm and the fluorescence intensity decreased significantly. Especially, the addition of trifluoromethanesulfonic acid, the maximum ultraviolet absorption wavelength is redshifted to 602 nm, and the fluorescence quenching. Nevertheless, the addition of nitric acid, hydrofluoric acid and phosphoric acid had no obvious effect on the optical properties of the flavanthrone compound. Also, even in different strong acid conditions the flavanthrone compound has excellent fluorescence stability and high fluorescence quantum yield of about 50%. To better comprehend the electronic properties, the values of the energy levels of the highest occupied molecular orbitals (HOMOs, EHOMO = -5.2937 eV) and the lowest unoccupied molecular orbitals (LUMOs, ELUMO = −2.7021 eV) of the flavanthrone as well as energy band gaps determined electrochemically (△E = 2.5916 eV) were carried out at the B3LYP/6-311G** level of the density functional theory (DFT) calculations.

Thermal stable characteristics of acid- and pepsin-soluble collagens from the carapace tissue of Chinese soft-shelled turtle (Pelodiscus sinensis)

The carapace from the Chinese soft-shelled turtle (Pelodiscus sinensis) is used as a traditional Chinese medicine. Acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from turtle carapace were isolated and characterized to screen novel collagen material in this study. Yields of 1.0% and 2.8% were obtained for ASC and PSC which contained glycine as the major amino acid and had high imino acid content. Both collagens had maximum ultraviolet absorption peaks of 220 nm. SDS-PAGE revealed that the structure of both collagens was similar, belonging to type I collagen. Relative viscosities of collagens were decreased as the temperature increased. Collagens showed minimum solubility at pH 8 and maximum solubility at a salt concentration of 3%. The denaturation temperature (Td) of PSC was higher whereas the melting temperature was lower than that of ASC. Both ASC and PSC appeared to be spongy like microstructure with fibrillar pores shown by scanning electron microscopy. The results suggest that collagens isolated from turtle carapace has high thermal stability with potential uses as new substitute for mammalian collagen in medicinal, food or biomaterial fields. However, their biological or pharmacological activities are needed to be further studied.

A near-infrared azadipyrromethene dye: Photophysical properties under different acidity conditions

We designed and synthesized the new structure azadipyrromethene from 4-bromo-2-hydroxyacetophenone through five steps, and tested the compound via five different acid conditions. The results indicated that the maximum ultraviolet absorption wavelength of azadipyrromethene is 763 nm, and the addition of methanesulfonic acid and hydrochloric acid solution significantly increased the ultraviolet absorbance of the compound within 10 h, but the fluorescence quantum yield decreased from 0.71 to around 0.05. However, under the condition of phosphoric acid, the photophysical properties of azadipyrromethene did not change significantly.

Performance of Single-Crystal Silicon Solar Cells With Mist-Deposited Nanocrystalline Quantum Dot Downshifting Films

The paper is concerned with an investigation of the effect of the mist-deposited downshifting nanocrystalline quantum dots (NQD) films both continuous and patterned on the performance of single-crystal commercial silicon solar cells. Different thicknesses of the NQD films are explored in an attempt to improve cell's efficiency in the ultraviolet (UV) range (below 400 nm) of the solar spectrum. The results obtained indicate that the maximum UV absorption is observed with a 50-nm-thick NQD film as reflected by on the average 45% increase in UV external quantum efficiency as compared with the solar cell without the NQD film. The patterned NQD films are showing improved performance in the visible range as compared with unpatterned NQD films without compromising the performance of the cell in the UV range of the solar spectrum. Also, an increase in power conversion efficiency by 12.5% is observed. Overall, an improvement of silicon solar cells performance using mist deposition of downshifting NQD films instead of spin-on coating as previously explored in other studies is demonstrated.

Photosynthetic Production of Sunscreen Shinorine Using an Engineered Cyanobacterium.

Mycosporine-like amino acids (MAAs) are secondary metabolites of a variety of marine organisms including cyanobacteria and macroalgae. These compounds have strong ultraviolet (UV) absorption maxima between 310 and 362 nm and are biological sunscreens for counteracting the damaging effects of UV radiation in nature. The common MAA shinorine has been used as one key active ingredient of environmentally friendly sunscreen creams. Commercially used shinorine is isolated from one red algae that is generally harvested from the wild. Here, we describe the use of Synechocystis sp. PCC6803 as a host for the heterologous production of shinorine. We mined a shinorine gene cluster from the filamentous cyanobacterium Fischerella sp. PCC9339. When expressing the cluster in Synechocystis sp. PCC6803, we observed the production of shinorine using LC-MS analysis, but its productivity was three times lower than the native producer. Integrated transcriptional and metabolic profiling identified rate-limiting steps in the heterologous production of shinorine. The use of multiple promoters led to a 10-fold increase of its yield to 2.37 ± 0.21 mg/g dry biomass weight, comparable to commercially used shinorine producer. The UV protection of shinorine was further confirmed using the engineered Synechocystis sp. PCC6803. This work was the first time to demonstrate the photosynthetic overproduction of MAA. The results suggest that Synechocystis sp. PCC6803 can have broad applications as the synthetic biology chassis to produce other cyanobacterial natural products, expediting the translation of genomes into chemicals.

New 4′-substituted benzoyl-β-D glycoside from the fruit pulp of Terminalia belerica with antiplatelet and antioxidant potency

BackgroundThe fruit Terminalia belerica is a rich source of vitamins, acids, and nutraceuticals which have free radical scavenging activity. Thus, the ethanolic extract of fruit and its isolated compound (Tb-01) were intended to estimate antiplatelet and antioxidant activities. MethodsThe ethanolic extract was submitted to Si-gel CC and the compound was isolated. The compound Tb-01 was characterized as benzoyl-β-D-(4′→10″ geranilanoxy)-pyranosides on the basis of spectral data [ultra violet (UV), infrared (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, and Mass Spectroscopy] and chemical analyses. The ethanolic extract and Tb-01 at different concentrations were in vitro screened for antiplatelet and antioxidant activity. The antiplatelet activity was carried out by using platelet rich plasma prepared by centrifugation of rabbit whole blood (containing 0.9% sodium citrate as anticoagulant) and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl, reducing power, and nitric oxide anion scavenging activity models. ResultsThe compound Tb-01 was an amorphous brownish powder, yield 0.64% (w/w), melting point 105–110°C, Retardation factor/Retention Value (Rf value) at 0.42 in methanol:chloroform (20:80) solvent system, UV absorption maxima at 243nm, and molecular peak [M + H]+ at 394.15 m/z. It was observed that the ethanolic extract and Tb-01 at different concentrations showed significant antiplatelet and antioxidant activity. The antioxidant activity, like scavenging of 1,1-diphenyl-2-picrylhydrazyl radicals, nitric oxide radical, and reductive power were found to be concentration-dependent and increased when increasing amounts of sample were used. ConclusionMass spectra and 1H NMR confirmed the isolated compound structure which was supported by 13C NMR and IR spectra. Tb-01could be promising for future applications in the treatment of blood clots, pulmonary embolism, and other related diseases.

Spectrophotometric estimation of raltegravir potassium in tablets.

Ultra violet spectrophotometric estimation of the raltegravir potassium, an integrase inhibitor antiretroviral agent was estimated by Ultra violet absorption maxima method at λmax of 328 nm and UV area under curve method in the wave length range of 323-333 nm. The Beer's law obeyed in the concentration range of 3-55 μg/ml and correlation coefficients were found to be more than 0.996 for both methods. The results of the analysis were 100.58±0.99 and 99.69±0.59 by absorption maxima and area under curve method respectively. Both the methods were validated as per ICH guidelines.

Solvent and Structure Effects on Electronic Absorption Spectra of the Isomeric Pyridinecarboxylic Acids

Ultraviolet absorption spectra of three isomeric pyridinecarboxylic acids (picolinic, nicotinic, and isonicotinic acids) were measured in 18 various solvents, in the wavelength range from 200 to 400 nm. In order to analyze the solvent effect on the obtained absorption maxima, the ultraviolet absorption frequencies of the electronic transitions in the carbonyl group of the examined acids were correlated using a total solvatochromic equation in the forms νmax = ν0 + sπ* + aα + bβ and νmax = ν0 + sπ* + bβ, where νmax is the absorption frequency (1/νmax), π* is a measure of the solvent polarity, α represents a scale of the solvent hydrogen bond donor acidity, and β represents a scale of the solvent hydrogen bond acceptor basicity. Correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The effects of two different solvent types on the ultraviolet absorption maxima of the examined acids were compared and discussed.

Synthesis and Identification of Heavy Metal Lead Artificial Antigen

Lead ions were coupled to protein carrier bovine serum albumin (BSA) and keyhole limpet hemocyanin (KLH) respectively. Diethylene Triamine Pentacetate Acid (DTPA) was used as bifunctional chelator. Pb-DTPA-Carrier protein, DTPA-Carrier protein and carrier protein were detected qualitatively with ICP-MS, UV spectrophotometer and electrophoresis. It turns out that the Pb-DTPA-Carrier protein contains certain concentration of heavy metal ion, the maximum ultraviolet absorption peak value of Pb-DTPA-Carrier protein significantly higher than that of DTPA-Carrier protein and carrier protein, and the electrophoresis reveals more vague bands of Pb-DTPA-Carrier protein with slower migrations speed comparing to the bands of the DTPA-Carrier protein and carrier protein. The result indicated that the artificial antigen for lead was successfully synthesized.

Effect of substituents and conjugated chain length on the UV spectra of α,ω‐di‐substituted phenyl polyenes

A series of α,ω‐di‐substituted phenyl polyenes, p‐X–Ph(CH = CH)nPh–p‐Y (n = 1, 2, or 3) were synthesized, and their ultraviolet (UV) absorption maximum wavelength were determined. The correlation between molecular structure and the maximum wavelength energy (wavenumber/cm−1) was carried out. The results show that the maximum wavelength energy of the title compounds is mainly affected by both substituent excited‐state parameters and maximum wavelength energy of the parent molecule. However, the two influence factors are not independent, and the action of substituent is governed by the parent molecular absorption energy. In the case of the compounds containing NO2 or NH2 groups, the influence of interaction of polarity parameters on the maximum wavelength energy must also be considered. In addition, the exploration was also made for the quantifying correlation of UV absorption maximum wavelength energy with the conjugated polarizability potential CPP replacing the parent molecular absorption energy. And the results indicate that the equation with CPP parameters is more accurate and convenient. Copyright © 2013 John Wiley & Sons, Ltd.

Synthesis of Al-doping ZnO nanoparticles via mechanochemical method and investigation of their structural and optical properties

In this study, pure and Al-doped ZnO nanoparticles were successfully synthesized by the mechanochemical method. The effect of doping on structural and optical properties was studied. The structural investigations of products confirmed the hexagonal wurtzite structure for all products and also it was observed that doping caused a little change in lattice parameters. The results obtained by SEM revealed that the average particle size of products increases by doping and nanoparticles have almost spherical morphology. UV–visible absorption and PL spectra showed that the maximum ultraviolet absorption wavelength of products increases and the optical band gap shifts from 3.15eV to 3.11eV, with increasing the Al concentration.

Extraction Process of Amaranthine Pigment Keeping the Water Wax Fuit Biological Active

Development natural pigment retained a variety of nutrition composition is extremely research value.Water Wax Trees Fruit was as raw materials,citric acid aqueous solution was as extracting agent.Amaranthine pigment extraction method were studied on fully grasping the stability of the natural amaranthine pigment and no damage to the water wax fruit biological activity.The effect of extraction yield were studied on Water Wax Trees Fruit natural amaranthine pigment.The results show that the better extraction conditions are extraction temperature at 70 °C, extraction time for 3h,citric acid concentration1.0 % , the material/liquid ration(g/ml) 1:5.The extraction yield is 2.95%.Ultraviolet absorption maximum wavelength is 280 nm.

Retinoids and retinoid-metabolic gene expression in mouse adipose tissues

Vitamin A and its analogs (retinoids) regulate adipocyte differentiation. Recent investigations have demonstrated a relationship among retinoids, retinoid-binding-protein 4 (RBP4) synthesized in adipose tissues, and insulin-resistance status. In this study, we measured retinoid levels and analyzed the expression of retinoid homeostatic genes associated with retinol uptake, esterification, oxidation, and catabolism in subcutaneous (Sc) and visceral (Vis) mouse fat tissues. Both Sc and Vis depots were found to contain similar levels of all-trans retinol. A metabolite of retinol with characteristic ultraviolet absorption maxima for 9-cis retinol was observed in these 2 adipose depots, and its level was 2-fold higher in Sc than in Vis tissues. Vis adipose tissue expressed significantly higher levels of RBP4, CRBP1 (intracellular retinol-binding protein 1), RDH10 (retinol dehydrogenase), as well as CYP26A1 and B1 (retinoic acid (RA) hydroxylases). No differences in STRA6 (RBP4 receptor), LRAT (retinol esterification), CRABP1 and 2 (intracellular RA-binding proteins), and RALDH1 (retinal dehydrogenase) mRNA expressions were discerned in both fat depots. RALDH1 was identified as the only RALDH expressed in both Sc and Vis adipose tissues. These results indicate that Vis is more actively involved in retinoid metabolism than Sc adipose tissue.

Studies on Bacterial Populations in Solutions of Phenols

Abstract The shape of time-survivor curves for E. coli suspended in aqueous solutions of benzylchlorophenol depends on the concentration of the bactericide. In some concentrations the last survivors exhibit unexpected multiplication. The death of the organisms is accompanied by the release of cell-constituents having an ultra-violet absorption maximum at 260 mμ. Growth occurred when E. coli exudate was added to aqueous suspensions of E. coli whereas in its absence the organisms died. The numbers of viable organisms depended upon the concentration of the added cell exudate. The fate of the last survivors of a suspension of E. coli in benzylchlorophenol solution was controlled by re-suspending them in components of the reaction mixture. Removal of cell-exudate produced rapid death and the removal of bactericide led to multiplication of the organisms. It is concluded that cell exudate constituted the nutrient substrate for multiplication of last survivors in an initially bactericidal system. The theories of disinfection and the influence of cell exudate upon the shape of time-survivor curves are discussed.

Physicochemical Properties of Protoporphyrin IX by Metal Ions in Acetonitrile-Water Mixture Solution

Porphyrin derivatives contain pyrrole rings, five membered heterocycles. These compounds have properties of a conjugated diene and of an amine. Delocalization of π electrons stabilizes the ring and their ultra-violet absorption maximum peak shifts to a longer wavelength. They can easily absorb visible light, and thus can utilize sunlight directly as a good photosensitizer. Re-cently, photodynamic therapy has been used in the management of various malignant tumors, including cancers of the skin, gas-trointestinal tract, lung and uterus.