UV-visible Data Research Articles

Synthesis, characterization and biological applications of curcumin-lysine based schiff base and its metal complexes

The Schiff base derived from curcumin and lysine and its Co, Ni, Cu and Zn(II) complexes have been synthesized and characterized by FT-IR, UV-Vis, 1H NMR and elemental analysis. Conductivity measurement showed a non-electrolytic complex. Thermogravimetric (TG/DTG) analyses of Cu complex confirm the stability followed by thermal decomposition in different steps. The UV-Vis and magnetic susceptibility data of the complexes suggest tetrahedral geometry around the central metal ion except the Cu(II) complex which has a square planar geometry. The XRD and SEM studies revealed the nanocrystalline behavior for the complex. The antimicrobial activity of the Schiff base and its metal chelates were screened against bacteria, such as E. coli and P. aeruginosa. The antifungal activity was screened against C. albicans. The result shows that metal chelates have better antimicrobial activity than the Schiff base. The larvicidal activity of the Schiff base and its metal complexes have been studied and the result revealed that the Cu(II) complex shows more activity than the Schiff base.

Efficient tuning of small acceptor chromophores with A1-π-A2-π-A1 configuration for high efficacy of organic solar cells via end group manipulation

Now a days, non-fullerene organic compounds are considered with keen interest for the greener energy and potential photovoltaic devices. Herein, novel acceptor chromophores (DPDVD1-DPDVD4) were designed via small acceptor DPDVR compound with A1-π-A2-π-A1 architecture using promising approach by redistribution of end-capped acceptor moieties. The effect of end-capped acceptor moieties on designed architecture for the photophysical, photovoltaic and electronic behavior was explored using quantum chemical study. Frontier molecular orbital (FMO) findings revealed that all the molecules (DPDVD1-DPDVD4) contained narrow band gaps. The central acceptor moiety (PzDP) was responsible for the transformation of charge in DPDVD1-DPDVD4. UV–Vis data disclosed that λmax values of DPDVD1-DPDVD4 compounds were existed in visible region (537.36–517.05 nm). Interestingly, DPDVD2 exhibited the reduced band gap with broader absorption spectra among all chromophores might be due to the negative inductive effect (−I) of the terminal acceptors. The open circuit voltage (Voc) analysis was performed at the interface between standard donor polymer (PTB7) and DPDVD2. The higher value (3.34 V) of Voc was observed for DPDVD2 among reference and designed compounds. Furthermore, reorganization energy findings exploited DPDVR-DPDVD4 shown lower values of λe than λh which indicated that these chromophores were the promising candidates for electron transportation mobilities. The larger charge mobilities with greater exciton dissociation in excited state for DPDVD2 were examined, subsequently this compound showed minimum value of λe (0.015739 eV) among all chromophores. Detailed studies reveal that the entitled molecules can behave as efficient electron acceptor molecules in organic solar cells (OSCs) that make them interesting candidates for the development of inexpensive optoelectronic devices.

Spectroscopic Analysis for Harnessing the Quality and Potential of Gemstones for Small and Medium-Sized Enterprises (SMEs)

Introduction of modern technologies and methods and quality analysis for the gemstone industry are the main strategic initiatives of the Small and Medium Development Authority (SMEDA) of Pakistan. In this regard, four natural gemstones Quartz, Pyrope-Almandine Garnet, Black tourmaline, and Amethyst brought from Hunza valley Pakistan were analyzed by state-of-the-art spectroscopic techniques including EDX, UV-VIS, and FTIR spectroscopy. EDX revealed the traces of Fe, Mg, and Ca in Pyrope-Almandine garnet, Mg and Fe in Black tourmaline, Au and Ca in Amethyst. UV-VIS data revealed the values of Urbach energies 520, 210, 460, and 430 meV, and the values of direct bandgap energies 5.14, 6.12, 5.54, 5.74 eV, respectively. The higher structural disorder due to the presence of Fe and other impurities in stones except Quartz was attributed to the higher values of Urbach energies and decrease in band gaps: FTIR data Fe-O and Si-O stretching vibration in Pyrope-Almandine garnet, Si-O bending vibrations and O-H stretching vibration in Quartz, Si-O-Si bending and stretching vibrations and C=O stretching vibrations in Black tourmaline, Ca-O stretching vibrations and Si-OH weak-vibrations in Amethyst. Photoluminescence results also showed useful information in investigating the properties of gemstones.

Utilization and simulation of innovative new binuclear Co(ii), Ni(ii), Cu(ii), and Zn(ii) diimine Schiff base complexes in sterilization and coronavirus resistance (Covid-19)

Abstract This article aimed at the synthesis and molecular docking assessment of new diimine Schiff base ligand, namely 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxyvinyl)hydrazono) methyl)-6-methoxyphenol (methoxy-diim), via the condensation of 1-(4-chloro-phenyl)-2-hydrazino-ethenol compound with 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxy vinyl) hydrazono)methyl)-6-methoxyphenol in acetic acid as well as the preparation of new binuclear complexes of Co(ii), Ni(ii), Cu(ii), and Zn(ii). The following synthesized complexes were prepared in a ratio of 2:1 (metal/ligand). The 1H-NMR, UV-Vis, and FTIR spectroscopic data; molar conductivity measurements; and microanalytical, XRD, TGA/DTG, and biological studies were carried out to determine the molecular structure of these complexes. According to the spectroscopic analysis, the two central metal ions were coordinated with the diamine ligand via the nitrogen of the hydrazine and oxygen of the hydroxyl groups for the first metal ions and via the nitrogen of the hydrazine and oxygen of the phenol group for the second metal ions. Molecular docking for the free ligand was carried out against the breast cancer 3hb5-oxidoreductase and the 4o1v-protein binding kidney cancer and COVID-19 protease, and good results were obtained.

Alternative Co-Initiators for Photocurable Biomaterials: Polymerisation, Quantum Yield of Conversion and Cytotoxicity

Cyclic acetals such as 1,3 benzodioxole (BZD), piperonyl alcohol (PA), and N-phenyl glycine (NPG) are naturally occurring compounds capable of acting as co-initiators during free-radical polymerisation, and potentially serve to offer non-allergic and biologically less toxic alternatives to conventional (tertiary) amines. The current study aimed to evaluate the use of cyclic acetals in concentrations of 0.5-6.0 mol % for photopolymerisation of an unfilled model dimethacrylate resin system, bisphenol-A-glycidyldimethacrylate (BisGMA), and triethylene glycol dimethacrylate (tegDMA), 1:1 wt.%) using the photosensitiser camphorquinone (CQ; λmax = 469 nm) in concentrations of 0.5-1.5 mol %. Conventional tertiary amines, namely, ethyl-4-dimethyamino benzoate (EDMAB) (aromatic) and dimethylaminoethyl methacrylate (DMAEMA) (aliphatic) were utilised for comparison purposes. Real-time degree of conversion (DC) was evaluated using Fourier transform near-infrared spectroscopy. To measure the effectiveness of these alternative compounds in facilitating CQ photon absorption, quantum yield of conversion of CQ per absorbed photon was calculated using UV-Vis spectroscopy. Cytotoxicity of NPG and cyclic acetals were assessed using MTT and Calcien AM to determine metabolic activity and cell viability, respectively. The result indicated that cyclic acetals were capable of facilitating free radical polymerisation as co-initiators at all three CQ concentrations (0.5, 1.0 and 1.5 mol %). Further, the use of NPG as a co-initiator resulted in post-irradiation DC values that were comparable to both EDMAB and DMAEMA across all three CQ concentrations. Based on the quantum yield of conversion of CQ, alternative compounds facilitated the hydrogen abstraction process, which provided high conversion of CQ molecules. UV-Vis absorption and quantum yield data revealed that NPG exhibited competitive effects in absorbing blue light photons, which might be attributed to the photolytic degradation of NPG and the formation of N-methylaniline. Indirect treatment of human dental pulp cells (HDPCs) with eluted extracts of NPG, BZD and PA exhibited relatively lower cytotoxicity when compared with HDPCs groups treated with no eluted extracts. The relative cytotoxicity of DMAEMA was comparable to that of PA. However EDMAB, CQ and the neat model resin media extracts resulted in significant cytotoxicity, with highest relative reduction in the number of viable cells observed in groups treated with neat model resin extracts, suggesting that bisGMA and tegDMA monomers played significant role in the overall cytotoxicity of photocurable systems involving HDPCs.

Synthesis and molecular docking studies of Zn(II)phthalocyanines containing anthraquinone moieties as selective ligands for G-quadruplex structures

New zinc(II) phthalocyanines (p-ZnPc and np-ZnPc) containing peripheral and non-peripheral positioned four anthraquinone moieties were synthesized by cyclotetramerization of 4-((2-(2-((8-Chloro-9,10-dioxo-9,10-dihydroanthracen-1-yl) amino) ethoxy) ethyl) thio) phthalonitrile and 3-((2-(2-((8-Chloro-9,10-dioxo-9,10-dihydroanthracen-1-yl) amino) ethoxy) ethyl) thio) phthalonitrile. All compounds were characterized by using a combination of analytical and spectroscopic techniques such as 1H, [Formula: see text]C NMR, FT-IR, UV-vis and MS spectral data. Also, molecular docking studies were performed using different G-quadruplex and double stranded nucleic acid fragments as possible interaction sites to predict the binding ability of the newly synthesized compounds.

Synthesis and evaluation of acetylferulic paeonol ester and ferulic paeonol ester as potential antioxidants to inhibit fish oil oxidation

Acetylferulic paeonol ester (APE) and ferulic paeonol ester (FPE) were synthesized, and their structures were confirmed by NMR, mass spectra, IR and UV–vis data. The antioxidant properties of the synthesized compounds were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and [(2-azino-bis (3-ethylbenzthiazoline)-6 -sulfonic acid] (ABTS) assay as well as the production of oxidation products (peroxides, conjugated dienes, thiobarbituric acid-reactive substances, free fatty acids and total aldehydes) in an elevated temperature (60 °C) storage trial of fish oil extracted from anchovy. Furthermore, the changes in fatty acid composition were monitored by gas chromatography-mass spectrometry. The results showed that APE was more effective in restraining fish oil oxidation compared to FPE, ferulic acid, paeonol and the commercial antioxidant-butylated hydroxytoluene (BHT). This study demonstrated molecular combinations obtained by covalent bonding two antioxidant active molecules can result in novel compounds with enhanced antioxidant activities.

Structural and optoelectronic properties change in Bi/In2Se3 heterostructure films by thermal annealing and laser irradiation

The amorphous materials are sensitive to external radiations and thermal annealing that brings changes in their structural and optical properties for optoelectronic applications. The present report shows the amorphous to crystalline structure transformation in Bi/In2Se3 by energy radiation and thermal annealing that modifies the linear as well as the nonlinear optical properties. The thermally evaporated Bi/In2Se3 film was subjected to 2.35 eV energy irradiation and 150 °C thermal annealing. The structural transition was probed by XRD, which revealed the formation of BiSe, Bi4Se3, and Bi2Se3 phases by replacing indium with an average crystallite size of ∼20 nm. The diffusion of Bi into In2Se3 host matrix modified the interfacial region as noticed from the field effect scanning electron microscopy pictures. The linear and nonlinear optical constants were evaluated from the UV–Visible data that show a significant change in the irradiated and annealed films due to the new phases. The change in direct and indirect bandgap is explained on the basis of density of defect states and degree of disorder. The significant change in the refractive index brings more freedom in designing multifunctional optoelectronic devices. The σopt and σelect changed noticeably with heat and energy treatment. The high value of χ3 (18.81 × 10−10 esu) for the Bi/In2Se3 film decreased significantly to 3.68 × 10−10 and 2.13 × 10−10 esu for the annealed and irradiated film. All the optical parameter changes due to annealing and irradiation are confined between the two-host materials In2Se3 and Bi/In2Se3. The corresponding changes were also observed in Raman spectroscopy data. The tuning of these linear and nonlinear parameters is useful for optoelectronics and photovoltaics.

Self-Assembling Systems Based on Pillar[5]arenes and Surfactants for Encapsulation of Diagnostic Dye DAPI.

In this paper, we report the development of the novel self-assembling systems based on oppositely charged Pillar[5]arenes and surfactants for encapsulation of diagnostic dye DAPI. For this purpose, the aggregation behavior of synthesized macrocycles and surfactants in the presence of Pillar[5]arenes functionalized by carboxy and ammonium terminal groups was studied. It has been demonstrated that by varying the molar ratio in Pillar[5]arene-surfactant systems, it is possible to obtain various types of supramolecular systems: host–guest complexes at equimolar ratio of Pillar[5]arene-surfactant and interpolyelectrolyte complexes (IPECs) are self-assembled materials formed in aqueous medium by two oppositely charged polyelectrolytes (macrocycle and surfactant micelles). It has been suggested that interaction of Pillar[5]arenes with surfactants is predominantly driven by cooperative electrostatic interactions. Synthesized stoichiometric and non-stoichiometric IPECs specifically interact with DAPI. UV-vis, luminescent spectroscopy and molecular docking data show the structural feature of dye-loaded IPEC and key role of the electrostatic, π–π-stacking, cation–π interactions in their formation. Such a strategy for the design of supramolecular Pillar[5]arene-surfactant systems will lead to a synergistic interaction of the two components and will allow specific interaction with the third component (drug or fluorescent tag), which will certainly be in demand in pharmaceuticals and biomedical diagnostics.

Sensitive Metal Oxide-Clay Nanocomposite Colorimetric Sensor Development for Aflatoxin Detection in Foods: Corn and Almond.

The work reports on zinc oxide bentonite nanocomposite (ZnOBt) chemical route synthesis, characterization, and investigation of curcumin (Cur) functionalization for a label-free colorimetric detection of total aflatoxins (AFs) in foods. XRD of ZnO nanoparticles (NPs) confirmed the wurtzite structure (2θ = 36.2°) and that of ZnOBt showed the intercalated interlayer composite phase. The Debye–Scherrer relation calculated the crystallite size as 20 nm (ZnO) and 24.4 nm (ZnOBt). Surface morphology by SEM exhibited flower-like hexagonal, rod-shaped ZnO NPs on the bentonite surface. Colorimetric reaction involved two-stage redox reactions between ZnOBt and dye Cur followed by AFs phenolic group and Zn(Cur)OBt. Cur gets oxidized at its diketone moiety in the presence of ZnOBt to form a red colored complex Zn(Cur)OBt, which further scavenge protons from AFs phenolic group, and gets oxidized to AFs-Zn(Cur)OBt (yellow). Binding of AFs-Zn(Cur)OBt is characterized by FT-IR ascribed to C–H bending (1966.615 cm–1), O–H stretching (3256.974 cm–1), and C=O stretching (1647.362 cm–1). 1H NMR chemical shifts (δ) (ppm) showed an increase in proton at the aliphatic region (0 to 4.4) while removal of proton in ether at 4.4 to 6 regions. Job plot calculation using UV–Vis data resulted in a higher total AF binding coefficient of Zn(Cur)OBt (Ka = 3.77 × 106 mol–1 L) compared to Zn(Cur)O (Ka = 0.645 × 106 mol–1 L) as well as a molar ratio of 1:1 by the Benesi–Hildebrand plot equation. Corn and almond food samples showed the total AFs LOD of 2.74 and 4.34 ppb, respectively. The results are validated with standard LC/MS-MS in compliance with MRL value as per the regulatory standard (EU).The NP-based method is facile and rapid and hence can be utilized for onsite detection of total AFs in foods.

Structure and luminescent property of a Sm3+ complex containing benzoyltrifluoroacetone and 1,2-bis[(anthracen-9-ylmethyl)amino]ethane ligands

The synthesis, structure, and luminescent propertiesof a samarium(III) complex (A2) containing benzoyltrifluoroacetone (HTFPB) and 1,2-bis[(anthracen-9-ylmethyl)amino]ethane (BAAE2) ligands are herein reported. The structure of A2 has been elucidated by infrared spectroscopy and single crystal X-ray diffraction. X-ray crystallographic analysis demonstrated that A2 has a mononuclear structure with a formula of Sm(TFPB)3(BAAE2) in which Sm3+ ion is coordinated to six O-atoms from three TFPB ligands and two N-atoms from one ancillary ligand (BAAE2). UV-Vis data show that A2 strongly absorbs in the region of 220-400 nm. Nonetheless, A2 gives poor emission due to a quenching effect of the anthracenyl moiety.

NHC-Stabilized 1,2-Dihalodiborenes: Synthesis, Characterization, and Reactivity Toward Elemental Chalcogens.

The 2-fold reduction of B2X4(NHC)2 (X = Cl, Br, I; NHC = (un)saturated N-heterocyclic carbene) yields the corresponding green-colored 1,2-dihalodiborenes B2X2(NHC)2, the 11B NMR resonances of which are strongly upfield-shifted upon descending the halide group. The diborenes crystallize as the trans isomers, with relatively short B═B double bonds (1.513(9) to 1.568(4) Å). Cyclic voltammetric experiments with these diborenes reveal reversible one-electron oxidation processes to the corresponding diboron radical cation (E1/2 = -1.16 to -1.50 V); the reducing power of B2X2(NHC)2 increasing with the electronegativity of the halide and for the less π-accepting unsaturated NHCs. The main UV-vis absorption (393-463 nm), which corresponds mainly to a highest occupied molecular orbital (HOMO) → lowest unoccupied molecular orbital (LUMO) transition, undergoes a blueshift upon descending the halide group and shows some dependence on the stereoelectronics of the NHC ligands. Computational analyses show that the HOMO of B2X2(NHC)2 is mostly localized on the B═B π bond, with the contribution from halide p orbitals decreasing down the group, and the saturated NHCs affording some π-bonding delocalization over the B-CNHC bonds. The calculated HOMO and LUMO energies decrease upon descending the halide group, while the HOMO-LUMO gap also decreases, correlating well with the cyclovoltammetry and UV-vis data. The reactions of B2Br2(NHC)2 with elemental sulfur and red selenium lead to the formation of the corresponding diborathiiranes and seleniranes, respectively, which were characterized by NMR and UV-vis spectroscopy, cyclic voltammetry, and X-ray diffraction analyses. In one case, an additional one-electron oxidation yields a unique cyclic B2Se radical cation. Computational analyses show that the localization of the HOMO and HOMO - 1 of the diboraseleniranes is inverted compared to the diborathiiranes.

Visually detecting cyanide ion in aqueous solution sensitively and selectively using a merocyanine salt with the help of a smartphone

Naked eye visual detection of cyanide ion (CN−) was explored in an aqueous-organic medium (1:1) by using a merocyanine (MC) based probe. The structure validation of the probe was accomplished using spectroscopic techniques. Evaluation of the probe in Tris buffer at pH 7.6 revealed yellow color as a result of its interaction with cyanide ion, which was originally pink in color. Inspection of UV–vis data revealed reduced intensities of absorption bands at 390 nm and 525 nm on adding cyanide ions in probe solution. An abrupt color change visible with the unaided eyes due to the interaction of the probe with cyanide ion proved advantageous in the development of a digital colorimetry-based analytical protocol for evaluation of CN− ions existence in solution. A change in chemical shift of protons in the 1H NMR spectrum implied interaction between the hydroxyl group proton of the probe and CN− ion that results in the displacement of the p-toluenesulfonate group by incoming CN− ion. Dynamic light scattering (DLS) studies also affirmed the aggregation of the probe and in its mixture with CN− ion. The calculation of parameters using density functional theory (DFT) with M06–2X functional further signaled the formation of a complex through the H-bond. Excitation parameters calculated using CAM-B3LYP studies also furnished results in support of experimental data.

Thermodynamic Study on the Dissociation and Complexation of Coumarinic Acid with Neodymium(III) and Dioxouranium(VI) in Aqueous Media

In the frame of a systematic study on the sequestering ability of natural antioxidants towards metal cations, the complexation of coumarin-3-carboxilic acid (HCCA) with neodymium(III) and dioxouranium(VI) (uranyl, UO22+), and overall stability constants of the resulting complexes, were evaluated from the pH-potentiometric titration data at 37 °C and in an aqueous solution (i.e., 0.16 mol/L NaClO4). The graphic representation of the complex’s concentration curves is given by the distribution diagrams, which provide a depiction of all the species present in the solution in the selected pH ranges. The protonation constant of HCCA was also determined to evaluate the competition of the ligand for the metal cations and H+. The ligand-to-metal concentration ratio was varied between 1 and 10, and the hydrogen ion concentration was decreased stepwise until the incipient precipitation of a basic salt of the metal, which occurred at different values depending on the specific metal cation and the ligand to metal ratio. Speciation profiles obtained by potentiometric titrations and supported by UV-Vis data show that a complexation occurs at a ligand-to-Nd(III) and to –UO22+ ratio of 1:1 and 2:1, with different degrees of deprotonation: Nd(OH)(CCA)+, UO2(OH)(CCA), UO2(OH)2(CCA)−, and Nd(OH)(CCA)2, UO2(CCA)2 and (UO2)2(OH)2(CCA)2.

Sub-level engineering strategy of nitrogen-induced Bi2O3/g-C3N4: a versatile photocatalyst for oxidation and reduction.

Herein, the α-Bi2O3 nanocrystal decorated by nitrogen dopant and its heterojunction nanocomposite with g-C3N4 (N0.1/Bi2O3/g-C3N4) is successfully fabricated for the first time, for photo-oxidation of RhB and photo-reduction of Cr(VI) to Cr(III). The resulting N0.1/Bi2O3/g-C3N4 (3%) nanocomposite showed an optimal Cr(VI) photo-reduction and RhB photo-oxidation rates under visible-light irradiation, being 3-4 times higher than that of pure α-Bi2O3. The results from XPS confirmed the substitution of nitrogen with various oxidation states from N3+ to Nx+ (x < 5), due to the existence of different nitrogen oxides including N-O, O-N=O, and NO3- in the crystal structure. We investigated the reaction mechanism using catalytic tests, impedance spectroscopy, EPR technique, and density functional calculations. The DFT calculations presented the appearance of a new mid-gap hybrid of p states, comprised of N 2p, O 2p, and Bi 6P states, which enhance light absorption capacity and narrow band gap. The theoretical results were in excellent agreement with experimental UV-Vis data. The N0.1/Bi2O3/g-C3N4 nanocomposite exhibited acceptable practical application value and recycling ability for removal of the contaminants. Such improved photocatalytic activity is originated from the modified band positions, new electron evolution pathway, introducing defects in α-Bi2O3 by insertion of N atoms into the Bi sites, and the enhanced charge carrier mobility between N0.1/Bi2O3 and g-C3N4. The strategy to form nitrogen-doped bismuth-based nanocomposites may open a new opportunity to design atomic-level electronic defects by feasible methods to obtain a versatile photocatalyst material with simultaneous photo-reduction and photo-oxidation ability for removal of Cr(VI) and organic dyes from water.

Quality control of mint species based on UV-VIS and FTIR spectral data supported by chemometric tools

Mints are valued for their specific essential oil used in food, pharmaceutical and cosmetic industry. Chemical compounds differing between species, cause changes in medicinal/pharmacological properties, antioxidant activities or smell sensations. For this reason fast procedure for quality control of at least two most popular mint species, peppermint and spearmint, is the issue at hand. UV-VIS spectrophotometry and FTIR-ATR spectroscopy were used for recording the spectral fingerprints of a collection of more than 20 mint varieties harvested in three periods. Two-step chemometric approach for mints quality control involved SIMCA (Soft Independent Modeling of Class Analogy) to filter out species other than peppermint and spearmint. The samples suspected to be either peppermint or spearmint underwent final discrimination using adequate discrimination tools PLS-DA (Partial Least Squares-Discriminant Analysis) or SVM (Support Vector Machines). The model performance ranged between 60 and 80% depending on spectroscopic data used for model training and the harvest season.

Chemometric Analysis of UV-Visible Spectral Fingerprints for the Discrimination and Quantification of Clinical Anthracycline Drug Preparation Used in Oncology.

In clinical treatment, the analytical quality assessment of the delivery of chemotherapeutic preparations is required to guarantee the patient's safety regarding the dose and most importantly the appropriate anticancer drug. On its own, the development of rapid analytical methods allowing both qualitative and quantitative control of the formulation of prepared solutions could significantly enhance the hospital's workflow, reducing costs, and potentially providing optimal patient care. UV-visible spectroscopy is a nondestructive, fast, and economical technique for molecular characterization of samples. A discrimination and quantification study of three chemotherapeutic drugs doxorubicin, daunorubicin, and epirubicin was conducted, using clinically relevant concentration ranges prepared in 0.9% NaCl solutions. The application of the partial least square discriminant analysis PLS-DA method on the UV-visible spectral data shows a perfect discrimination of the three drugs with a sensitivity and specificity of 100%. The use of partial least square regression PLS shows high quantification performance of these molecules in solution represented by the low value of root mean square error of calibration (RMSEC) and root mean square error of cross validation (RMSCECV) on the one hand and the high value of R-square on the other hand. This study demonstrated the viability of UV-visible fingerprinting (routine approach) coupled with chemometric tools for the classification and quantification of chemotherapeutic drugs during clinical preparation.

Determination of Time since Deposition of Fingerprints via Colorimetric Assays.

Past investigations involving fingerprints have revolved heavily around the image of the fingerprint—including the minutiae, scarring, and other distinguishing features—to visually find a match to its originator. Recently, it has been proven that the biochemical composition can be used to determine originator attributes, such as sex, via chemical and enzymatic cascades. While this provides pertinent information about the originator’s identity, it is not the only piece of information that can be provided. This research was designed with three goals in mind: (1) identify how long it would take before an aged female fingerprint could no longer be differentiated from a male fingerprint, (2) identify a correlation between the data collected and a specific time since deposition (TSD) time point, and (3) identify if a specific amino acid could be contributing to the decreasing response seen for the aging fingerprints. Using ultraviolet–visible (UV–vis) spectroscopy, aged fingerprints were evaluated over the course of 12 weeks via three chemical assays previously used for fingerprint analysis—the ninhydrin assay, the Bradford assay, and the Sakaguchi assay. As fingerprints age, the conditions they are exposed to cause the biochemical composition to decompose. As this occurs, there is less available to be detected by analytical means. This results in a less intense color production and, thus, a lower measured absorbance. The results displayed here afforded the ability to conclude that all three goals set forth for this research were accomplished—a female fingerprint can be differentiated from a male fingerprint for at least 12 weeks, UV–vis data collected from aged fingerprints can be correlated to a TSD range but not necessarily a specific time point, and the decomposition of at least a single amino acid can afford the ability to estimate the TSD of the fingerprint.

Electrical properties of an Ag/ZnS/p–Si heterojunction obtained by sputtered ZnS thin film

ZnS thin films were deposited on both soda-lime glass and p–Si substrates by radio frequency (RF) sputtering of a single ZnS target. The morphological, structural, and optical properties of the films were analyzed. It was seen that the thin films had (111) and (200) orientations of ZnS structure. The particle size distribution of the SEM image showed that the ZnS thin film had a 44.00 ± 0.56 nm average particle size. The optical band gap of ZnS thin films was calculated as 3.7 eV using UV–vis data. The electrical and photoelectrical properties of an Ag/ZnS/p–Si heterojunction were analyzed using current–voltage (I–V) and capacitance–voltage (C–V) measurements. The results showed that the device had 0.694 eV barrier height and 449 Ω series resistance values. In addition, the photodiode of the device was analyzed by I–V measurements under a solar simulator with AM1.5 global filter. Finally, the barrier height value obtained from C–V measurements was compatible with the I–V method.

Study the photo catalytic activity of titanium dioxide nanoparticles and the impact on the degradation of methylene blue

In this study, titanium dioxide (TiO2) pure and doped prepared with tungsten at 5, 7 and 9 %, using pulse laser ablation method. The influence of different doping ratio of tungsten investigated on the structural properties and optical properties. X-ray measurement showed that the crystal size was increased by increasing doped concentration. From UV-visible data it has been found that the tungsten doping leads to a change in the optical band gap. ApplicationTiO2 as photo catalyst was studied on the degradation of methylene blue (MB) dye under UV illumination, which revealed the highest degradation of MB at a ratio of 9%.