Maximum Of Absorption Spectrum Research Articles

Low-Resolution Rotational Spectrum of (CD3)2CDOH

Low-resolution frequency spectra of deuterated isopropyl alcohol (CD3)2CDOH were calculated in the range 0–1200 GHz using additive modeling of low-resolution molecular spectra by high-resolution microwave spectra. The most probable frequency range of the absorption spectra maxima was determined.

A novel solid-solution garnet Yb:YAG-MnASG with enhanced spectral properties

A novel solid-solution garnet Yb3+ doped Y3Al5O12Mn3Al2(SiO4)3 (Yb:YAG-MnASG) has been designed and grown for the first time. The polycrystalline materials, crystal growth, crystal structures, absorption and emission spectra, energy level schema, fluorescence lifetime and laser performance parameters were investigated in detail. Owing to the inhomogeneity in the local environment of Yb3+ caused by the cationic substitutions of Mn2+ for Y3+, Si4+ for Al3+ and high crystal-field strengths caused by distorted host sites, both of the absorption and emission spectral bandwidth of Yb:YAG-MnASG crystal are broadened compared with Yb:YAG. The maximal full width at half maximum (FWHM) of absorption spectra around 940 nm and emission spectra around 1030 nm for Yb:YAG-MnASG crystal are almost 1.2 and 2.5 times larger than those of Yb:YAG crystal, respectively. The results reveal that the novel solid-solution garnet Yb:YAG-MnASG is an excellent candidate for ultrafast pulse laser crystal.

Preparation and Physicochemical Properties of [6]Helicenes Fluorinated at Terminal Rings.

The first racemization-stable helicene derivatives fluorinated at terminal rings, 1,2,3,4-tetrafluoro[6]helicene (6) and 1,2,3,4,13,14,15,16-octafluoro[6]helicene (15), were synthesized via the Wittig reaction followed by oxidative photocyclization in an overall yield of 41% of 6 and 76% of 15. The changed electronic structure in fluorinated helicenes was reflected in a slight shift of UV-vis absorption, fluorescence excitation, and emission spectra maxima when compared to unsubstituted [6]helicene. Cyclic voltammetry revealed a moderate decrease in the HOMO-LUMO gap with increasing fluorination. The specific rotation of tetrafluoro[6]helicene 6 enantiomers was found to be approximately 25% lower than that of unsubstituted [6]helicene. The theoretical study of the racemization barrier suggested a reasonable shift toward higher energy with increasing fluorination. The increasing fluorination also significantly affected the intermolecular interactions in the crystal lattice. The observed CH···F interactions led to the formation of 1D-molecular chains in the crystal structures of both fluorinated helicenes.

DEVELOPMENT AND VALIDATION OF ANALYTICAL METHOD TO QUANTIFY THE DISSOLUTION OF CINARIZIN IN CAPSULES COMPOUNDED

Cinnarizine (CIN) is used in the treatment of cerebral circulatory, peripheral circulatory and balance disorders. An analytical method was developed and validated to determine the dissolution of cinnarizine (CIN) in capsules compounded by ultraviolet detection spectrophotometry. The resolutions of the Agência Nacional de Vigilância Sanitária nº. 899 of May 29, 2003 and nº. 166 of July 24, 2017 were used as the guide for validation of analytical methods. CIN showed high solubility in 0.1 mol.L-1 hydrochloric acid at 37 ° C (9.43 mg.mL-1), selectivity / specificity in the presence of other components (0.35 %), maximum absorption spectrum in 251 nm; linearity (r = 0.9999); precision (RSD repet.: 0.09%, RSD inter.: 1.10%); accuracy (LQC = 99.9%, MQC = 99.5%, HQC = 100.7%); limits of detection and quantification of 0.042 and 0.42 μg.mL-1, respectively. In the parameter robustness it has been proven that the proposed method does not suffer significant variations. The validated analytical method is easy to perform and has reliable selectivity / specificity, linearity, precision, accuracy, limits of detection, limits of quantification and robustness. Therefore, the ultraviolet detection spectrophotometry method is applicable to determine CIN in capsules compounded in simple, accurate and low cost dissolution assays.

Rapid biosynthesis and characterization of silver nanoparticles from the leaf extract of Tropaeolum majus L. and its enhanced in-vitro antibacterial, antifungal, antioxidant and anticancer properties

Eco-friendly biosynthesis of nanoparticles from medicinal plants as reducing agent has gained importance due to its potential therapeutic uses. In the present study Silver nanoparticles (AgNPs) were eco-friendly synthesized using the leaf extracts of the medicinal plant Tropaeolum majus. The obtained AgNPs were characterized by UV - visible spectrum, FTIR, SEM and XRD which clearly showed the reduction of Ag+ ions to Ag0. In addition, the aqueous and ethanolic extracts were analyzed for phytochemicals and its antioxidant activities. GC–MS spectrum showed the presence of 25 compounds with benzeneacetic acid as the dominant contents. The synthesized AgNPs revealed maximum absorption spectrum at 463 nm and FTIR vibrational peaks at 3357.46, 21,966.52, 2118.42, 1637.27, 658.571 and 411.728 cm−1 respectively. SEM and XRD studies evidenced the nature of nanocrystalline with face centered cubic (fcc) crystal structure. Both AgNPs and plant extracts showed more inhibition activity against Pseudomonas aeroginosa compared to other bacteria with MIC value of 6.25 μg/ml. Antifungal activities was higher for Penicilium notatum with MIC value 31.2 μg/ml. The IC50 values for MCF7 for aqueous extract were found to be 4.68 μg/ml, ethanol extract 7.5 μg/ml, AgNPs 2.49 μg/ml, and doxorubicin 1.4 μg/ml. The IC50 values for VERO cell line for aqueous extract was 8.1 μg/ml, ethanol extract with 6.8 μg/ml, silver nanoparticles 5.3 μg/ml and doxorubicin 2.6 μg/ml respectively. Conclusively, the antibacterial, antifungal, antioxidant and anticancer properties of the synthesized AgNPs from Tropaeolum majus act as major therapeutic drug for microbial infectious disease and other health associated disorders.

BIOGENIC SYNTHESIS SILVER NANOPARTICLES USING PELTOPHORUM PTEROCARPUM LEAF EXTRACTS AND ITS ANTIMICROBIAL EFFICACY AGAINST SELECTIVE PATHOGENS

Objective: The present study was aimed to screen silver nanoparticles (AgNPs) using different plant extracts and also to study their antimicrobial property against different human pathogens.Methods: Nine different plants, namely Parthenium hispidum, Vinga rose, Catheranthus roseus, Phyllanthus amarus, Azadirachta indica, Jatropa curcas, Tectona grandis, Ocimum sanctum, and Peltophorum pterocarpum were screened for the synthesis of AgNPs. The AgNPs were synthesized using leaf extracts and was well characterized using a UV-Visible spectrophotometer, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and zeta potential measurement. The AgNPs was tested for their antibacterial and antifungal efficacy using agar well diffusion method.Results: Among the nine different plant extracts screened, AgNPs synthesized using Peltophorum pterocarpum leaf extract showed good stability even after one month with maximum absorption spectra of 425 nm. The synthesized AgNPs was found to be spherical in shape with an average size ranging from 20 to 60 nm. The EDX spectrum reveals the presence of silver peaks and the XRD spectrum confirms the crystalline nature of AgNPs. A Maximum zone of inhibition of 18.04±0.74 was found when the synthesized AgNPs was tested against B. subtilis, and 12.34±0.31 against A. niger when the concentration was AgNPs was maintained at 100 µg/ml.Conclusion: The results of the present study conclude that the AgNPs synthesized using Peltophorum pterocarpum leaf extracts is found to be stable and possesses broad-spectrum antibacterial activity against different tested pathogens.

Photosystem I application in biohybrid polymer solar cells

The use of Bio-photonic systems has attracted a lot of attention recently specially in the field of solar energy conversion and photovoltaic materials the use of photosynthetic organs of plants is very promising. The energy conversion in the process of photosynthesis is close to 100% and it’s environmental compatibly are the main reasons for why photosynthesis has attracted the attention of energy system designers and researchers. The way of solar energy conversion in photosynthesis indicates a great potential as a fount of renewable energy. Use of the photosynthetic components in photosensors and photovoltaic devices solitarily, has disadvantages such as low extracted current compared to other kinds of photovoltaic materials. Accordingly, for more useful and better application, these photosynthetic components could be used as the optimizer of the other species of photovoltaic materials and solar cells. photosystem1 protein complex, which is the main member of photosynthetic components has maximum absorption spectrum wavelength at 430nm and 665nm. Therefore, it can be an appropriate complement for polymeric solar cells with their absorption spectrum at the green wavelength region. In this paper we have used the photosystem1 protein complex in the inverted polymer solar cell with structure of ITO/P3HT:ICBA/PS1/Al and positive results have been observed. So that the polymer solar cells efficiency was enhanced from 4.3% to 4.53%.

Experimental and theoretical study on structure and spectroscopic properties of 2-bromo-3-N-(N',N'-dimethylformamidino) benzanthrone.

The goal of present research is a theoretical and experimental investigation of geometrical structure, electronic properties, absorption and fluorescence spectra prediction for 2-bromo-3-N-(N',N'-dimethylformamidino)benzanthrone. As a result of conformational analysis, two rotamers have been found with a rotational barrier of 5.45kcal/mol. Absorption and fluorescence spectra maxima in the solvent (ethanol) have been calculated using the concepts of the Jablonsky diagram. The obtained values of the absorption and fluorescence maxima (437 and 679nm, respectively) correspond to the experimental values (447 and 659nm). The abnormally large Stokes shift is associated with the redistribution of electron density, as well as flattening of the structure of the molecule in the excited state. According to the frontal molecular orbital analysis data, the peak in the long-wave part of the absorption spectra is created by an electron transition from the highest occupied molecular orbital (HOMO) to the lowest occupied molecular orbital (LUMO) (π→π*). Substitute group does not participate in the formation of absorption and fluorescence spectra.

Optical properties of a microcavity based on a nanocrystalline SiC film

The optical properties of one-dimensional microcavity based on nanocrystalline SiC (nc-SiC) films containing nanocrystals of cubic and rhombohedric polytypes (R24 and R27, respectively) have been studied. It was revealed that resonance absorption maxima in absorption spectra measured at room temperature varied from 2.17 to 2.79 eV for the nc-SiC films 300–450 thick. To explain the thickness dependence of resonance absorption in the microcavities based on heteropolytypic nc-SiC films, the model of exciton–polariton states in the one-dimensional microcavity based on nanocrystalline SiC film has been proposed.

Green-shifting of SWS2A opsin sensitivity and loss of function of RH2-A opsin in flounders, genus Verasper.

We identified visual opsin genes for three flounder species, including the spotted halibut (Verasper variegatus), slime flounder (Microstomus achne), and Japanese flounder (Paralichthys olivaceus). Structure and function of opsins for the three species were characterized together with those of the barfin flounder (V. moseri) that we previously reported. All four flounder species possessed five basic opsin genes, including lws, sws1, sws2, rh1, and rh2. Specific features were observed in rh2 and sws2. The rh2‐a, one of the three subtypes of rh2, was absent in the genome of V. variegatus and pseudogenized in V. moseri. Moreover, rh2‐a mRNA was not detected in M. achne and P. olivaceus, despite the presence of a functional reading frame. Analyses of the maximum absorption spectra (λmax) estimated by in vitro reconstitution indicated that SWS2A of M. achne (451.9 nm) and P. olivaceus (465.6 nm) were blue‐sensitive, whereas in V. variegatus (485.4 nm), it was green‐sensitive and comparable to V. moseri (482.3 nm). Our results indicate that although the four flounder species possess a similar opsin gene repertoire, the SWS2A opsin of the genus Verasper is functionally green‐sensitive, while its overall structure remains conserved as a blue‐sensitive opsin. Further, the rh2‐a function seems to have been reduced during the evolution of flounders. λmax values of predicted ancestral SWS2A of Pleuronectiformes and Pleuronectidae was 465.4 and 462.4 nm, respectively, indicating that these were blue‐sensitive. Thus, the green‐sensitive SWS2A is estimated to be arisen in ancestral Verasper genus. It is suggested that the sensitivity shift of SWS2A from blue to green may have compensated functional reduction in RH2‐A.

UV absorption spectra and the physical nature of the optical properties of pyridoxine hydrochloride

A study of the nature of electronic transitions in different structural forms of pyridoxine hydrochloride molecule shows that the maxima in experimental absorption spectra at wavelengths 244 ± 1 nm, 310 ± 1 nm (pH 12.5), 291 ± 1 nm (pH 1.1, pH 4.1), 258 ± 1 nm, 291 ± 1 nm, and 324 ± 1 nm (pH 4.15) are, along with the corresponding lines in theoretical spectra, due to electron transitions from occupied molecular p-orbitals localized on the nitrogen atoms in the structure of pyridine rings to the vacant p-orbitals of double C=N bonds.

Influence of the methyl group at C=C bridging bond of stilbene on the longest wavelength maximum in ultraviolet absorption spectra

Influence of the methyl group at C=C bridging bond of stilbene on the longest wavelength maximum in ultraviolet absorption spectra

Size-Specific ZnO Quantum Dots as Onsager Cavity in Ooshika–Mataga–Lippert Equation

The influence of the surrounding solvent medium to a solute molecule in solution can be treated within the framework of Onsager reaction field model which is based on the assumption that the solute is reduced to a point dipole at the center of a spherical cavity inside the solvent that can be described as the homogeneous, polarizable medium of specific dielectric constant. When the solute molecules are excited in solution of the polar solvent, the changes in the photophysical properties of the solute are manifested through shifts in the maxima of absorption and fluorescence spectra and the observation can be interpreted in terms of the Ooshika–Mataga–Lippert equation. Over several decades, a wide variety of organic molecules as fluoroprobes have been explored to reveal the polarity of their immediate solvent environment. However, while these molecular probes, with diameters less than 10 A, have been employed so far in the literature as Onsager cavities, the limiting value of their radii has not been restr...

Natural Deys from Fruit Waste as a Sensitizer for Dye Sensitized Solar Cell (DSSC)

Dye-sensitized solar cell (DSSC) is one of the potential candidates for the next generation solar cells. One of the most attractive features of the DSSC is the low production costs. The utilization of natural dyes is a new area for investigation due to their unique capability to absorb photons from natural sunlight or artificial light and convert it into electric current. The purpose of this study is to determine the potential of natural dye from red dragon fruit waste as a dye sensitizer. Red dragon fruit peel is initially extracted using methanol and the solution absorption spectra then is characterized using UV-Vis spectrophotometer. The absorption spectra is measured within a wavelength range of 400-800 nm. The characterization results show that the maximum absorption spectrum is at a wavelength of 446 nm. The natural dye solution then is used to immerse Fluorine Tin Oxide (FTO) coated with titanium dioxide (TiO2). The glass FTO is immersed in the dye solution for 24 hours. DSSC then is prepared by sandwiching the working electrode and counter electrode. An electrolyte solution is used to fill the interface between the two electrodes. The current and voltage (I-V) characteristics of DSSC is finally measured using amperemeter and voltmeter. The results indicated that the natural dye from the peel of red dragon fruit has potential as a dye sensitizer. Further research is still required to improve the performance of the DSSC.

Abnormal effect of hydroxyl on the longest wavelength maximum in ultraviolet absorption spectra for bis-aryl Schiff bases

Two sets of bis-aryl Schiff bases that contain 4(or 4′)-OH and 2(or 2′)-OH were synthesized. The first set consists of 4-HOArCH=NArY and XArCH=NArOH-4′, and the second set consists of 2-HOArCH=NArY and XArCH=NArOH-2′. Their ultraviolet absorption spectra were measured and investigated. A very interesting phenomenon was observed by analyzing their wave number νmax (cm−1) of longest wavelength maximum λmax (nm) of ultraviolet. Compared with the change regularity of the νmax of XArCH=NArY (where the X and Y excluded OH), the 4′-position hydroxyl (4′-OH) and 2′-position hydroxyl (2′-OH) have abnormal performance. The details are the following: the 4′-OH contributes an additional red shift to the νmax of XArCH=NArOH-4′ (λmax increase), whereas the 2′-OH contributes an additional blue shift to the νmax of XArCH=NArOH-2′ (λmax decrease). In addition, there are ortho steric effects of all 2-OH and 2′-OH on the νmax for 2-HOArCH=NArY and XArCH=NArOH-2′, and the ortho steric effect contributes a red shift to their νmax. These experimental facts can provide an important theoretical reference for us using aryl Schiff base compounds as optical materials and performing the molecular design.

Green Synthesis of Silver Nanoparticles Using Arachis hypogaea (Ground Nut) Root Extract for Antibacterial and Clinical Applications

The present study focused on the green synthesis of silver nanoparticles (AgNPs) using Arachis hypogaea (ground nut) root extract for the antibacterial and clinical application. The presence of major phytochemical compounds are found to be 2H-Pyaran,2,5-diethenyltetrahydro, Didodecyl phthalate, Decanoic acid, Tetradecanoic acid, Bis(2-ethylhexyl) phthalate, Dodecanoic acid, Phosphonic acid, 2-(4-Methoxyphenyl)-5-(4-methoxynaphthyl) thiophene and Methyl 2-(N-Benzylimino)-4-chloro-3,3-dimethylbutanoate by GC–MS. Nanoparticles synthesis is confirmed by UV–Vis analysis by observing the maximum absorption spectrum at 450 nm. XRD and SEM–EDX results reveals the synthesized nanoparticles are cubic crystalline with agglomerated particles of silver oxide with biomolecules present around it. TEM images clearly shows that the biosynthesized nanoparticles are mostly spherical and irregular shaped with an average particles size of 30 nm. Highest susceptibility pattern of silver nanoparticle against Enterococcus sp. (35 ± 0.4 mm) which followed by Pseudomonas sp. (33 mm) and Staphylococcus aureus (29 mm). Green synthesized nanoparticles are coated over the commercially available clinical band aid cloth by dip coating method. Silver nanoparticle incorporated band aid cloth showed good antibacterial activity against the harmful bacteria which usually cause infection and interfere during wound healing. Our findings revealed that green nanoparticle has a good antibacterial action against harmful bacteria and showed good response for efficient clinical application.

Two novel Yb:YAG-based garnet solid solutions with broader spectral bandwidth

Two novel solid solutions of Yb:YAG and Ca3Al2(SiO4)3, Yb:YAG and Mg3Al2(SiO4)3 in various molar ratios were synthesized by solid-state reactions, respectively. The spectral bandwidth remarkably increased with increasing M3Al2(SiO4)3 (M=Ca and Mg) contents, and the maximal full width at half maximum (FWHM) of absorption and emission spectra for the solid solutions are almost 9 and 3 times larger than that of Yb:YAG, respectively. This large broadening of spectral bandwidth can be attributed to the inhomogeneity in the local environment of Yb3+ caused by the cationic substitutions of Ca2+ (Mg2+) for Y3+, Si4+ for Al3+ and the high crystal-field strengths caused by distorted host sites. Meanwhile, the fluorescence lifetimes of solid solutions decrease with the increases of M3Al2(SiO4)3 contents.

Influence of the side-group at C=N bridging bond of bis-aryl Schiff bases on the wavelength of absorption maximum of ultraviolet absorption spectra

The compounds N-(benzylidene)-anilines XArCH=NArY (XBAY), N-(phenyl-ethylene)-anilines XArC(CH3)=NArY (XPEAY) and N-phenyl-α-phenylnitrones XArCH=N(O)ArY (XPNY) have bridging group CH=N, C(CH3)=N and CH=N(O) respectively, in which the C(CH3)=N has a side-group methyl CH3 at carbon end and the CH=N(O) has a side-group O atom at nitrogen end. In this work, a series of XPEAY and XPNY were synthesized, and their longest wavelength maximum λmax (nm) of ultraviolet absorption spectra were measured. Then the change regularity of the νmax (cm-1, νmax=1/λmax) of XPEAY and XPNY were investigated, and they were compared with that of XBAY (reported by ref.26). The results indicate: (1) There are no good linear relationships between the νmax of XBAYs and XPEAYs or XPNYs. (2) In case of a same set of X-Y group couples, the distribution of λmax of XPEAYs is larger than that of XPNYs. (3) The side-group CH3 makes the effect of σ(X) larger than that of σ(Y) on the νmax of XPEAYs, whereas the O atom makes the effect of σ(Y) larger than that of σ(X) on the νmax of XPNYs. (4) The cross-interaction between X and Y has important effect on the all νmax. However, the cross-interaction between CH3 and X/Y has not important effect on the νmax of XPEAY, and the cross-interaction between O and X/Y has not important effect on the νmax of XPNY. Copyright © 2016 John Wiley & Sons, Ltd.

Vibronic Structures in Absorption and Fluorescence Spectra of Firefly Oxyluciferin in Aqueous Solutions.

To elucidate the factors determining the spectral shapes and widths of the absorption and fluorescence spectra for keto and enol oxyluciferin and their conjugate bases in aqueous solutions, the intensities of vibronic transitions between their ground and first electronic excited states were calculated for the first time via estimation of the vibrational Franck-Condon factors. The major normal modes, overtones and combination tones in absorption and fluorescence spectra are similar for all species. The theoretical full widths at half maximum of absorption spectra are 0.4-0.7eV and those for the fluorescence spectra are 0.4-0.5eV, except for phenolate-keto that exhibits exceptionally sharp peak widths due to the dominance of the 0-0' or 0'-0 band. These spectral shapes and widths explain many relevant features of the experimentally observed spectra.

Ultra-broadband and polarization-insensitive wide-angle terahertz metamaterial absorber

In this paper, an ultra-broadband and polarization insensitive terahertz (THz) metamaterial absorber is presented and investigated. With the optimization of the structural parameters, resonant peaks are merged into a broadband absorption spectrum. The simulation results demonstrate that a wide bandwidth of 3.1THz is obtained in the range from 2.6 to 5.7THz, where the absorption is higher than 90% for the normal incident THz waves. The full width at half maximum (FWHM) of absorption spectrum is 95% with respect to central frequency (∼4THz), which is five times greater than the FWHM of a single layer structure. Furthermore, this structure can keep the absorption above 88% over a large frequency range (>2.5THz) when the incident angle is smaller than 50°. This metamaterial absorber can find potential applications in terahertz imaging and stealth technology.