Spectrophotometric Measurements Research Articles

New Cu(II) and Zn(II) complexes with diethyl phenyl (N-phenylsulfamoylamino) methyl phosphonate: Synthesis, characterisation, DFT/M11 studies, NBO, DOS, QTAIM and RDG analysis

The stability constants (βij) and the thermodynamic parameters (ΔH°, ΔS° and ΔG°) of the complexes between diethyl phenyl (N-phenylsulfamoylamino) methyl phosphonate with Cu(II) and/or Zn(II) ions were determined by UV-visible spectrophotometric measurements in methanol at room temperature. The stable (1:2) solid-state mononuclear complexes were synthesised and characterised by FTIR, 1H-NMR, elemental analysis and magnetic moment measurements. In the DFT study, the predicted structural parameters with four exchange-correlation functionals were compared with experimental data. Their performance in predicting the vibration frequencies was also tested. Subsequently, with the best functionals thus obtained, calculations were performed on the most stable (1:2) complexes to obtain information on their structures and properties. The most stable geometrical structure, structural parameters, vibrational frequencies, UV-vis absorption spectra and global reactivity indices were carried out. The calculated results were in good agreement with the experimental findings. In order to gain further insights on the complexes properties non-linear optics (NLO), natural bond orbital (NBO), density of states (DOS) and quantum theory of atoms in molecule (QTAIM) analyses were performed. In addition, attractive bonds and van der Waals interactions were explored and visualized with reduced density gradient analysis (RDG). Finally, molecular docking was performed with Auto-Dock 4.2 to study the interactions between donors (DPSAMP or metallic complexes) and receptors [Escherichia coli (PDB code: 1HNJ) or Candida albicans (PDB code: 1H1W)].

Microscale assessment of iodate fortificant in food-grade salt using the potassium iodide/polyvinyl alcohol colorimetric reagent

A rapid and straightforward spectrophotometric measurement of iodate in food-grade sodium chloride was developed based on the formation of a purple-red polyvinyl alcohol-iodine complex monitored at 490 nm. The conditions that influence the colorimetric reactions were optimized using a univariate approach. The method exhibited optimum results using 2% polyvinyl alcohol, 10 mM KI, and 0.5 M phosphoric acid. A matrix-matched calibration curve was prepared to eliminate interference due to the presence of NaCl and to provide a direct reading of iodate concentration in salt from the absorbance reading. Under optimum conditions, a linear calibration plot was observed from 5 to 140 mg iodate per kilogram (r = 0.9931). The method exhibited a sensitivity of 6.8 × 10−3 (mg iodate per kg of salt)−1 with a detection limit of 0.61 mg kg−1. The method was applied in actual samples, and the results agreed well with the titration method at a 95% confidence level using a paired t-test. The method supports the green analytical method as evaluated using Green Analytical Procedure Index (GAPI) and Analytical Eco-scale.

Intensive linear and nonlinear optical studies of thermally evaporated amorphous thin Cu-Ge-Se-Te films

This article is devoted to completing the study of linear and nonlinear optical characteristics of thermally evaporated a-CuxGe20-xSe40Te40, CGST, (0 ≤ x ≤ 20 at.%) thin films. The film thickness and rate of deposition were fixed in 2000 Å and 100 Å/s, respectively. Optical constants of CGST-films have been deduced from spectrophotometric measurements in the spectral range 300nm-2500 nm. The VB and CB potentials have been determined; their values increase from 0.344 eV to 0.404 eV for the CB, while increases from (-0.864 eV) to (-0.641 eV) for VB, as Cu-percentage increases. Wemple-DiDomenico single oscillator model is applied to obtain dispersion energies and parameters. The single oscillator energy decreases from 2.411 eV to 2.232 eV, while the dispersion energy increases from 14.974 eV to 20.763 eV, as Cu-ration increases. Many other important optoelectrical and dielectric parameters have also been discussed, like static refractive index, average oscillator wavelength, oscillator-length strength parameters. The surface and volume energy loss functions, optical complex conductivity (real and imaginary parts), electronic polarizability, and some nonlinear optical parameters are also well-discussed. Total electronic polarizability values increase from 4.560 Å to 3.088 Å, while the plasma frequency increases from 4.200×1014 Hz to 3.970×1014 Hz. All mapped parameters have been discussed and linked to each other, as well as studying their dependence on Cu-ratio.

Spectroscopic studies of preparation conditions role on the shielding properties of MoO3-doped Na2O–ZnO–P2O5

Glassy samples from the undoped ternary system Na2O–ZnO–P2O5 in combination with other samples from the same system doped with variable amounts of MoO3 (0.25, 0.5, or 1 gm/batch) were successfully melted under ordinary, oxidizing, or reducing conditions followed by annealing. Fourier transform infrared spectrophotometric measurements in combination with optical absorption spectra were recorded before and after doping with variable concentrations of MoO3 in multiple melting media both as prepared or after being subjected to (8 Mrad) gamma irradiation dose. The studied spectral properties of the glasses were correlated with variations with the existing valence state of the Mo ions and the effects of gamma irradiation on the optical spectra and IR vibrational bands together with the role of the condition of melting the batches. The optical spectra of the glasses reveal pronounced UV and visible bands due to trace iron (Fe3+) ions as impurities or the sharing of the low valence states of the added molybdenum ions. The FTIR peaks show condensed spectra of phosphate groups (Q2, Q3), and the effects of dopant are limited because of low percent. Gamma irradiation causes distinct variations in the undoped spectra, but the MoO3-doped glasses show some shielding behavior.

Lanthanide metal−organic frameworks based on planar π-conjugated ligands for white light emission, temperature and chemical sensing

Two stable three-dimensional lanthanide metal-organic frameworks, Ln-MOFs of [M2O(BDCPO)1.5(H2O)7]·2H2O (Eu for CUST-621, Tb for CUST-622) are successfully constructed using π-electron riched ligand N,N′-bis(2,4-dicarboxyphenyl)-oxalamide (H6BDCPO) and Eu and Tb metal ions under solvothermal conditions. The appropriate chromophores in ligands can effectively sensitize Ln3+ ions, resulting in luminescence emission. The crystal structures are determined by single X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, infrared spectrophotometer and luminescence measurements. Triple emission centers are successfully designed and realized the solid-state white light (SSWL) performance, whose CIE coordinates are close to ideal white light (0.32, 0.33). Furthermore, the temperature sensitivity tests indicate that the two materials can be used to sense the temperature in the range of 303–423 K with remarkable color change. The maximum sensitivity are 6.86% K−1 and 7.73% K−1 at 423 K, respectively. Moreover, CUST-621 and CUST-622 can be used as multi-responsive luminescence sensors to Fe3+ and Cr2O72−, with high sensitivity, long-time stability and remarkable selectivity with resistance to interference from other ions. This work supply a general way to construct Ln-MOFs materials for multifunctional luminescence properties for sensing fields.

On the determination of spectral optical characteristics of the earth atmosphere

Spectral optical characteristics of the earth atmosphere are used and can be used for the physical state analysis of the atmosphere and right accounting of radiation extinction in carring out of environmental remote sensing, determination of the composition and properties of aerosols and solar energy absolute spectrophotometric measurements as well as for the selection of the optimum conditions of solar energetic installations work and an evaluation of the atmosphere pollution in the different regions of the globe.

Retrieval of tropospheric aerosol, NO<sub>2</sub>, and HCHO vertical profiles from MAX-DOAS observations over Thessaloniki, Greece: intercomparison and validation of two inversion algorithms

Abstract. In this study we focus on the retrieval of aerosol and trace gas vertical profiles from multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations for the first time over Thessaloniki, Greece. We use two independent inversion algorithms for the profile retrievals: the Mexican MAX-DOAS Fit (MMF) and the Mainz Profile Algorithm (MAPA). The former is based on the optimal estimation method (OEM), while the latter follows a parameterization approach. We evaluate the performance of MMF and MAPA, and we validate their retrieved products with ancillary data measured by other co-located reference instruments. The trace gas differential slant column densities (dSCDs), simulated by the forward models, are in good agreement, except for HCHO, where larger scatter is observed due to the increased spectral noise of the measurements in the UV. We find an excellent agreement between the tropospheric column densities of NO2 retrieved by MMF and MAPA (slope=1.009, Pearson's correlation coefficient R=0.982) and a good correlation for the case of HCHO (R=0.927). For aerosols, we find better agreement for the aerosol optical depths (AODs) in the visible (i.e., at 477 nm) compared to the UV (at 360 nm), and we show that the agreement strongly depends on the O4 scaling factor that is used in the analysis. The agreement for NO2 and HCHO near-surface concentrations is similar to the comparison of the integrated columns with slightly decreased correlation coefficients. The seasonal mean vertical profiles that are retrieved by MMF and MAPA are intercompared, and the seasonal variation in all species along with possible sources is discussed. The AODs retrieved by the MAX-DOAS are validated by comparing them with AOD values measured by a CIMEL sun photometer and a Brewer spectrophotometer. Four different flagging schemes were applied to the data in order to evaluate their performance. Qualitatively, a generally good agreement is observed for both wavelengths, but we find a systematic bias from the CIMEL sun photometer and Brewer spectrophotometer measurements, due to the limited sensitivity of the MAX-DOAS in retrieving information at higher altitudes, especially in the UV. An in-depth validation of the aerosol vertical profiles retrieved by the MAX-DOAS is not possible since only in very few cases is the true aerosol profile known during the period of study. However, we examine four cases, where the MAX-DOAS provided a generally good estimation of the shape of the profiles retrieved by a co-located multi-wavelength lidar system. The NO2 near-surface concentrations are validated against in situ observations, and the comparison of both MMF and MAPA revealed good agreement with correlation coefficients of R=0.78 and R=0.73, respectively. Finally, the effect of the O4 scaling factor is investigated by intercomparing the integrated columns retrieved by the two algorithms and also by comparing the AODs derived by MAPA for different values of the scaling factor with AODs measured by the CIMEL sun photometer and the Brewer spectrophotometer.

Synthesis and characterization of 4-[2(3-acetylphenyl) diazenyl]-3,5-dimethylphenol for heterojunction photodiode applications

Synthesis of azo dye, 4-[2(3-acetylphenyl) diazenyl]-3,5-dimethylphenol (ADD), is presented. The structural, linear optical and non-linear optical properties of ADD are studied together with the Ag/ADD/p-Si/Al heterojunction photodiode characteristics. The synthetic ADD is examined by using both Fourier transform infrared spectroscopy and nuclear magnetic resonance techniques. Its structure is also investigated using both X-ray diffraction and scanning electron microscopy techniques. Based on the spectrophotometric measurements of ADD thin film, several linear-optical parameters are calculated from the absorption spectra. The single-oscillator model is used to explain the dispersion parameters of ADD thin films. Semi-empirical relations are used to calculate the non-linear optical parameters from the linear optical parameters. The good optical properties of ADD thin films qualify ADD to be used in optoelectronic applications. So, Ag/ADD/p-Si/Al heterojunction photodiode is fabricated and its electrical properties are studied. Moreover, the Ag/ADD/p-Si/Al photodiode parameters (sensitivity, resistivity and detectivity) show good response to different illumination intensities.

The use of H-form clinoptilolite to preconcentrate trace amounts of Nd(III) from aqueous solution under dynamic conditions

Rare earth elements (REE) are vital in the industry, particularly in the manufacturing of high-tech products. REE are emitted in enormous amounts into the environment as a result of their increased use in industry. The sorption technique is one of the most efficient ways to extract rare earth elements in low quantities. The results of a dynamic study of the sorption capabilities of the H-form of Transcarpathian clinoptilolite towards Nd(III) are presented in this work. X-ray diffraction, FT-IR, zeta potential analysis, and potentiometric titration were used to analyze the sorbent. The breakthrough capacity of H-clinoptilolite toward Nd(III) was 3.1 mg g−1 under ideal conditions (pH = 7.5, sorbent thermal treatment temperature: t = 150 °C). The desorption efficiency of Nd(III) has been investigated using acids and different mineral salt solutions. The optimum desorbing agent appeared to be acidified (pH 4) 1 M KNO3 solutions. A method for preconcentrating trace amounts of Nd(III) using acid-modified Transcarpathian clinoptilolite in a solid-phase extraction mode is proposed, followed by spectrophotometric measurement of this rare earth element.

Determination of ionization constants for sequinidazole in aqueous solutions and mixtures of water with isopropanol, acetonitrile and ethanol

Seknidazole is a drug from the 5-nitroimidazole group with a number of side-effects. This drug is virtually unexplored from the point of view of chemico-toxicological analysis (CTA). Therefore, the development of a set of methods for the detection and quantification of secnidazole in biological fluids for use in CTA is an urgent task. Aim. To study the acid-base equilibrium of secnidazole in aqueous solutions and mixtures of water with amphiphilic solvents and determine the corresponding ionization constants. Materials and methods. Spectrophotometric measurements were performed using a SPEKOL®1500 single-beam spectrophotometer. An EV-74 ionomer was used to control the pH of the solutions. Seknidazole solutions in the concentrationof 1000 μg/ml were used in the experiment. Results and discussion. Absorption spectra of secnidazole in water and mixtures of water and amphiphilic solvents in the pH range studied showed four isobestic points characterizing two protolytic equilibria (equilibrium 1 – 240 and 295 nm, equilibrium 2 – 261 and 297 nm). The position of the isobestic points of equilibrium 2 fluctuated in the range ± 3 nm; it was due to the presence of tautomeric transformations for the molecular form of secnidazole. Conclusions. The acid-base equilibria of secnidazole in aqueous solutions and mixtures of water with amphiphilic solvents have been studied. It has been shown that in a strongly alkaline medium there is an anionic form of secnidazole R–, with further decrease in the pH value the molecular form HR appears, in a strongly acidic medium the final product – a protonated form H2R+ – is formed. The ionization constant 1 has been determined for aqueous solutions of secnidazole, mixtures of water with isopropanol, acetonitrile and ethanol. It is impossible to determine the equilibrium constant 2 by the method specified.

Two-Step PEF Processing for Enhancing the Polyphenol Concentration and Decontaminating a Red Grape Juice.

This study’s aim is to evaluate Pulsed Electric Fields (PEF) technology as an alternative method for the processing of red grape juice. For this purpose, two PEF treatments were applied: first to grapes for polyphenol enrichment of the juice, and subsequently for microbial decontamination of the obtained juice. Juice obtained from PEF-treated grapes (5 kV/cm, 63.4 kJ/kg) had the polyphenol content 1.5-fold higher and colour intensity two times higher of control juices by spectrophotometric measurement (p ≤ 0.05). A subsequent decontamination treatment by PEF (17.5 kV/cm and 173.6 kJ/kg) achieved inactivation of the present microbiota (yeasts, moulds, and vegetative mesophilic bacteria) below detection level (<30 CFU/mL). Furthermore, PEF-treated juices were microbiologically stable up to 45 days, even at abusive refrigeration storage temperatures (10 °C). PEF juice quality and sensory characteristics were similar to a fresh juice; they were neither affected by the PEF decontamination treatment, nor by storage time and temperature. Results obtained in this study demonstrate the considerable potential of PEF for the production of a polyphenol-enriched and microbially stabilized red grape juice as a unique and sustainable alternative for the juice industry, while avoiding enzymatic and heat treatments.

Implementation of an Analytical Method for Spectrophotometric Evaluation of Total Phenolic Content in Essential Oils.

Over the past decade, there has been growing interest in polyphenols’ research since these compounds, as antioxidants, have several health benefits, such as preventing neurodegenerative diseases, inflammation, cancer, cardiovascular diseases, and type 2 diabetes. This study implements an analytical method to assess the total phenolic content (TPC) in essential oils using Folin–Ciocalteu’s phenol reagent and quantifies the individual phenolic compounds by liquid chromatography. Thus, the research design and methodology included: (1) extraction of essential oil from dried thyme leaves by hydrodistillation; (2) spectrophotometric measurement of TPC by Folin–Ciocalteu method; and (3) identification and quantification of individual phenolic compounds by high-performance liquid chromatography-diode array detection/electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS). Results revealed a TPC of 22.62 ± 0.482 mg GAE/100 µL and a polyphenolic profile characterized by phenolic acids (52.1%), flavonoids (16.1%), and other polyphenols (31.8%). Thymol, salvianolic acid A, and rosmarinic acid were the major compounds of thyme essential oil. The proposed analytical procedure has an acceptable level of repeatability, reproducibility, linearity, LOD (limit of detection), and LOQ (limit of quantification).

Silver@Hydroxyapatite functionalized calcium carbonate composites: characterization, antibacterial and antibiofilm activities and cytotoxicity

Silver@Hydroxyapatite functionalized calcium carbonate composites have been prepared through different sustainable methods, without involving the use of organic solvents and additional reagents. The composites were characterized by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, spectrophotometric measurements and X-ray photoemission spectroscopy. From the characterization techniques, the obtained nanoparticles resulted constituted essentially by Ag3PO4 nanostructures, whose size varied from 70 to 100 nm and were uniformly distributed on the calcium carbonate surface. Upon VIS irradiation, the formation of plasmonic nanostructures with a more defined dimensional distribution and reduced size could be obtained, as a prove of a partial silver reduction. All composites exhibited good antimicrobial and antibiofilm activities against Staphylococcus aureus and Pseudomonas aeruginosa whereas they showed low cytotoxicity effects towards human skin keratinocytes and human fibroblasts. These results enable these composites to be promising candidates for biomedical and pharmaceutical applications.

Improved Enzymatic Assay and Inhibition Analysis of Redox Membranotropic Enzymes, AtGALDH and TcGAL, Using a Reversed Micellar System

Reversed micelles are helpful to solubilize otherwise insoluble membranotropic or membrane-bound enzymes in their functional form, thus enabling activity assay and inhibition analysis. However, in the case of redox enzymes, this task is further complicated by the necessity to select an appropriate electron-acceptor (EA) which, ideally, should be compatible with spectrophotometric measurements in reversed micelles. Here, we have identified such an EA and successfully used it in a reversed micellar environment to assay the activity of two homologous enzymes from mitochondria: l-galactone-1,4-lactone dehydrogenase (EC 1.3.2.3) from Arabidopsis thaliana (AtGALDH) and galactonolactone oxidase (EC 1.3.3.12) from Trypanosoma cruzi (TcGAL), differing in their membranotropic properties, with TcGAL being almost insoluble in water and particularly difficult to assay. Furthermore, we have demonstrated the possibility to use this assay for inhibition analysis, with an elucidation of the mechanism and inhibition parameters, which otherwise could not be possible. In order to perform inhibition analysis, we improved the approach for the determination of activity of such membrane enzymes based on a reversed micellar system as membrane matrix, necessary for the functioning of membrane enzymes. A number of electron acceptors (EA) were tested for AtGALDH and optimal conditions of activity determination for AtGALDH were found. The suggested method was successfully applied to the study of the inhibition of AtGALDH by lycorine, and the mixed competitive mechanism of inhibition of AtGALDH by lycorine was determined. The developed approach to inhibitor analysis was applied for TcGAL, insoluble in water membrane, and the method provides new opportunities for searching effective inhibitors that may be potential drugs. Indeed, galactonolactone oxidase from Trypanosoma cruzi (TcGAL) and AtGALDH are homologues, and the inhibition of TcGAL stops the vital biosynthesis of vitamin C in parasite Trypanosoma cruzi from causing Chagas disease. The approach proposed can be applied for the screening of inhibitors of AtGALDH and TcGAL, as well as to study properties of other membrane enzymes including determination of the mechanisms of inhibition, structure and catalytic properties, the impact of membrane components (for example lipids), and so on.

Inferred Measurements of the Zodiacal Light Absolute Intensity through Fraunhofer Absorption Line Spectroscopy with CIBER

Abstract Scattered sunlight from the interplanetary dust (IPD) cloud in our solar system presents a serious foreground challenge for spectrophotometric measurements of the extragalactic background light (EBL). In this work, we report on inferred measurements of the absolute intensity of the zodiacal light (ZL) using the novel technique of Fraunhofer line spectroscopy on the deepest 8542 Å line of the near-infrared Ca ii absorption triplet. The measurements are performed with the narrow band spectrometer (NBS) on board the Cosmic Infrared Background Experiment sounding rocket instrument. We use the NBS data to test the accuracy of two ZL models widely cited in the literature, the Kelsall and Wright models, which have been used in foreground removal analyses that produce high and low EBL results respectively. We find a mean reduced χ 2 = 3.5 for the Kelsall model and χ 2 = 2.0 for the Wright model. The best description of our data is provided by a simple modification to the Kelsall model, which includes a free ZL offset parameter. This adjusted model describes the data with a reduced χ 2 = 1.5 and yields an inferred offset amplitude of 46 ± 19 nW m−2 sr−1 extrapolated to 12500 Å. These measurements elude to the potential existence of a dust cloud component in the inner solar system whose intensity does not strongly modulate with the Earth’s motion around the Sun.

Assessment of sun-safety education behavior via spectrophotometric evaluation: A preliminary study.

Biases inherent in self-assessment of sun exposure and sun-safe behavior may lead to inaccurate conclusions about the effectiveness of sun-safety educational programs. We aimed to compare self-reports to objective measures of sun exposure, when examining the effectiveness of passive versus active educational interventions. From May to June 2018, 73 participants recruited at a dermatology clinic were sequentially assigned to receive sun-safety education through one of 3modes: interactive online module, video, or no education. A baseline Sun Exposure and Behavior Inventory (SEBI) questionnaire was administered, and spectrophotometric measurements of sun-exposed and sun-protected areas were taken and reported in the CIE L*a*b* color space. Participants were followed 4-8 and 16weeks after the initial visit where the SEBI was re-administered, and serial measurements of skin color were taken. The change in SEBI scores and L*a*b values, as calculated by the individual typology angle (ITA°), was analyzed. There was a significant increase in skin darkening in all the groups at 4-8 and 16weeks follow-up. There was no statistically significant difference between the groups in the magnitude of color change. However, subjectively at 4-8 weeks post-intervention, participants in the interactive module and video groups had significantly improved self-reported SEBI scores compared to control (p<.05, Kruskal-Wallis). By 16weeks, only the interactive module group showed significant improvement in SEBI scores compared to control (p<.05, ANOVA). In determining the effectiveness of sun-safety programs, spectrophotometric evaluation of sun-induced skin pigmentation can allow for a more complete evaluation of self-reported sun exposure and sun-protective behavior.

Catalase Activity in Hot-Air Dried Mango as an Indicator of Heat Exposure for Rapid Detection of Heat Stress

The growing market for dried fruits requires more attention to quality parameters. Mango and other tropical fruits are commonly dried at temperatures ranging from 40 °C to 80 °C. Convincing evidence suggests that the nutritional quality of dried fruits is best preserved when dried at low temperatures ≤50 °C, whereas increasing drying temperatures lead to the degradation of the most valuable nutrients inside the fruit. Currently, there is no system or direct measurement method that can assist in identifying the quality deterioration of dried fruits caused by excessive heat exposure during drying. From this perspective, the activity of the heat-sensitive enzyme ‘catalase’ was used for the first time to evaluate and compare mango slices dried at 40 °C, 60 °C and 80 °C. Various methods, including direct and indirect flotation tests and spectrophotometric measurements, were explored to measure the residual catalase activity in the dried samples. Results showed that the spectrophotometry and indirect flotation test produced the best results, revealing a significant difference (p &lt; 0.05) in the catalase activity of mango slices dried at 40 °C, 60 °C and 80 °C, which the direct-dried mango flotation test failed to predict. Furthermore, this study demonstrates the potential applicability of catalase activity to indicate heat stress in dried mango slices processed at different temperatures.

Membrane damage as mechanism of photodynamic inactivation using Methylene blue and TMPyP in Escherichia coli and Staphylococcus aureus

The worldwide threat of antibiotic resistance requires alternative strategies to fight bacterial infections. A promising approach to support conventional antibiotic therapy is the antimicrobial photodynamic inactivation (aPDI). The aim of this work was to show further insights into the antimicrobial photodynamic principle using two photosensitizers (PS) of different chemical classes, Methylene Blue (MB) and TMPyP, and the organisms Escherichia coli and Staphylococcus aureus as Gram-negative and Gram-positive representatives. Planktonic cultures of both species were cultured under aerobic conditions for 24 h followed by treatment with MB or TMPyP at various concentrations for an incubation period of 10 min and subsequent irradiation for 10 min. Ability to replicate was evaluated by CFU assay. Accumulation of PS was measured using a spectrophotometer. The cytoplasmic membrane integrity was investigated by flow cytometry using SYBR Green and propidium iodide. In experiments on the replication ability of bacteria after photodynamic treatment with TMPyP or MB, a killing rate of 5 log10 steps of the bacteria was achieved. Concentration-dependent accumulation of both PS was shown by spectrophotometric measurements whereby a higher accumulation of TMPyP and less accumulation of MB was found for S. aureus as compared to E. coli. For the first time, a membrane-damaging effect of TMPyP and MB in both bacterial strains could be shown using flow cytometry analyses. Furthermore, we found that reduction of the replication ability occurs with lower concentrations than needed for membrane damage upon MB suggesting that membrane damage is not the only mechanism of aPDI using MB.

Epitaxial Growth and Optical Properties of Laser Deposited CdS Thin Films

In this study, cadmium Sulfide (CdS) thin films were synthesized on quartz substrates using an infrared pulsed laser deposition (IR-PLD) technique under high vacuum (~10−6 Torr) conditions. X-ray diffraction was used to evaluate the structural features. According to X-ray analysis, the deposited CdS films are crystalline and have a favored orientation on a plane (110) of an orthorhombic. The peak intensity and the average crystallite size increases with increasing the film thickness. After annealing at 300 °C, the orthorhombic phase transformed into a predominant hexagonal phase and the same result was obtained by SEM photographs as well. Spectrophotometric measurements of transmittance and reflectance of the CdS films were used to derive optical constants (n, k, and absorption coefficient α). The optical band gap energy was found to be 2.44 eV. The plasma plume formation and expansion during the film deposition have also been discussed. The photocurrent response as a function of the incident photon energy E (eV) at different bias voltages for different samples of thicknesses (85, 180, 220 and 340 nm) have been studied, indicating that the photocurrent increases by increasing both the film thickness and photon energy with a peak in the vicinity of the band edge. Thus, the prepared CdS films are promising for application in optoelectronic field.

The dynamic interplay between AMPK/NFκB signaling and NLRP3 is a new therapeutic target in inflammation: Emerging role of dapagliflozin in overcoming lipopolysaccharide-mediated lung injury

Acute lung injury (ALI) is one the most common causes of morbidity and mortality in critically ill patients. In this study, we examined for first time the role of dapagliflozin (DPGZ) in lipopolysaccharide (LPS)-induced ALI in rats and determined the underlying molecular mechanisms by evaluating the effects of DPGZ on adenosine monophosphate kinase (AMPK), nuclear transcription factor kappa B, nucleotide-binding and oligomerization domain-like receptor 3 inflammasome activation. Treatment of acute lung injured rats with either low dose (5 mg/kg) or high dose (10 mg/kg) DPGZ significantly decreased oxidative stress by decreasing malondialdehyde and nitric oxide tissue levels with a significant increase in spectrophotometric measurements of superoxide dismutase, catalase, and reduced glutathione levels. DPGZ treatment resulted in a significant anti-inflammatory effect as indicated by suppression in myeloperoxidase activity, MCP-1, IL-1β, IL-18, and TNF-α levels. DPGZ treatment also increased p-AMPK/t-AMPK with a significant reduction in NF-kB P65 binding activity and NFĸB p65 (pSer536) levels. These effects of DPGZ were accompanied by a significant reduction in NLRP3 levels and NLRP3 gene expression and a significant decrease in caspase-1 activity, which were also confirmed by histopathological examinations. We conclude that DPGZ antioxidant and anti-inflammatory activity may occur through regulation of AMPK/NFĸB pathway and inhibition of NLRP3 activation. These results suggest that DPGZ represents a promising intervention for the treatment of ALI, particularly in patients with type 2 diabetes.