Search results for: in-situ laser raman spectroscopy

Authors: Elham Moniri, Homayon Ahmad Panahi, Mitra Hoseini

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In this research, clinoptilolite zeolite was prepared. The zeolite was characterized by fourier transform infra-red spectroscopy. Then the effects of various parameters on Cr(III) sorption such as pH, contact time were studied. The optimum pH value for sorption of Cr(III) was 6 respectively. The sorption capacity of zeolite for Cr(III) were 7.9 mg g−1. A recovery of 89% was obtained for the metal ions with 0.5 M nitric acid as the eluting agent. The effects of interfering ions on Cr(III) sorption was also investigated. The profile of Cr(III) uptake on this sorbent reflects a good accessibility of the chelating sites in the clinoptilolite zeolite. The developed method was utilized for the determination of Cr(III) in environmental water samples by flame atomic absorption spectrometry with satisfactory results.

Keywords: clinoptilolite zeolite, chromium, environmental sample, determination

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Authors: Mohamed Rehan, Gamil E. Ibrahim, Mohamed S. Abdel-Aziz, Shaimaa R. Ibrahim, Tawfik A. Khattab

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The utilization of natural products in finishing textiles toward multifunctional applications without side effects is an extremely motivating goal. Hibiscus sabdariffa usually has been used for many traditional medicine applications. To develop an additional use for Hibiscus sabdariffa, an extraction of bioactive compounds from Hibiscus sabdariffa followed by finishing on cellulosic fibers was designed to cleaner production of the value-added textiles fibers with multifunctional applications. The objective of this study is to explore, identify, and evaluate the bioactive compound extracted from Hibiscus sabdariffa by different solvent via ultrasonic technique as a potential eco-friendly agent for multifunctional cellulosic fabrics via two approaches. In the first approach, Hibiscus sabdariffa extract was used as a source of sustainable eco-friendly for simultaneous coloration and multi-finishing of cotton fabrics via in situ incorporations of nanoparticles (silver and metal oxide). In the second approach, the micro-capsulation of Hibiscus sabdariffa extracts was followed by coating onto cotton gauze to introduce multifunctional healthcare applications. The effect of the solvent type was accelerated by ultrasonic on the phytochemical, antioxidant, and volatile compounds of Hibiscus sabdariffa. The surface morphology and elemental content of the treated fabrics were explored using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). The multifunctional properties of treated fabrics, including coloration, sensor properties and protective properties against pathogenic microorganisms and UV radiation as well as wound healing property were evaluated. The results showed that the water, as well as ethanol/water, was selected as a solvent for the extraction of natural compounds from Hibiscus Sabdariffa with high in extract yield, total phenolic contents, flavonoid contents, and antioxidant activity. These natural compounds were utilized to enhance cellulosic fibers functionalization by imparting faint/dark red color, antimicrobial against different organisms, and antioxidants as well as UV protection properties. The encapsulation of Hibiscus Sabdariffa extracts, as well as wound healing, is under consideration and evaluation. As a result, the current study presents a sustainable and eco-friendly approach to design cellulosic fabrics for multifunctional medical and healthcare applications.

Keywords: cellulosic fibers, Hibiscus sabdariffa extract, multifunctional application, nanoparticles

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Authors: M. Ertas, A. C. Onel, G. Ekinci, B. Toydemir, S. Durdu, M. Usta, L. Colakerol Arslan

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To develop AZ91D magnesium alloys with improved properties, we have applied TiN and VN/TiN multilayer coatings using DC magnetron sputter technique. Coating structure, surface morphology, chemical bonding and corrosion resistance of coatings were analyzed by x-ray diffraction (XRD), scanning electron microscope (SEM), x-ray photoelectron spectroscopy (XPS), and tafel extrapolation method, respectively. XPS analysis reveal that VN overlayer reacts with oxygen at the VN/TiN interface and forms more stable TiN layer. Morphological investigations and the corrosion results show that VN/TiN multilayer thin film coatings are quite effective to optimize the corrosion resistance of Mg alloys.

Keywords: AZ91D Mg alloys, high corrosion resistance, transition metal nitride coatings, magnetron sputter

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Authors: Sai Snehitha Yadavalli, K. Sruthi, Swati Ghosh Acharyya

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Heavy metal ions are toxic to humans and all living species when exposed in large quantities or for long durations. Though Fe acts as a nutrient, when intake is in large quantities, it becomes toxic. These toxic heavy metal ions, when consumed through water, will cause many disorders and are harmful to all flora and fauna through biomagnification. Specifically, humans are prone to innumerable diseases ranging from skin to gastrointestinal, neurological, etc. In higher quantities, they even cause cancer in humans. Detection of these toxic heavy metal ions in water is thus important. Traditionally, the detection of heavy metal ions in water has been done by techniques like Inductively Coupled Plasma Mass Spectroscopy (ICPMS) and Atomic Absorption Spectroscopy (AAS). Though these methods offer accurate quantitative analysis, they require expensive equipment and cannot be used for on-site measurements. Anodic Stripping Voltammetry is a good alternative as the equipment is affordable, and measurements can be made at the river basins or lakes. In the current study, Square Wave Anodic Stripping Voltammetry (SWASV) was used to detect the heavy metal ions in water. Literature reports various electrodes on which deposition of heavy metal ions was carried out like Bismuth, Polymers, etc. The working electrode used in this study is a polyvinyl chloride (PVC) modified glassy carbon electrode (GCE). Ag/AgCl reference electrode and Platinum counter electrode were used. Biologic Potentiostat SP 300 was used for conducting the experiments. Through this work of simultaneous detection, four heavy metal ions were successfully detected at a time. The influence of modifying GCE with PVC was studied in comparison with unmodified GCE. The simultaneous detection of Cd⁺², Fe⁺², Co⁺², Pb⁺² heavy metal ions was done using PVC modified GCE by drop casting 1 wt.% of PVC dissolved in Tetra Hydro Furan (THF) solvent onto GCE. The concentration of all heavy metal ions was 0.2 mg/L, as shown in the figure. The scan rate was 0.1 V/s. Detection parameters like pH, scan rate, temperature, time of deposition, etc., were optimized. It was clearly understood that PVC helped in increasing the sensitivity and selectivity of detection as the current values are higher for PVC-modified GCE compared to unmodified GCE. The peaks were well defined when PVC-modified GCE was used.

Keywords: cadmium, cobalt, electrochemical sensing, glassy carbon electrodes, heavy metal Ions, Iron, lead, polyvinyl chloride, potentiostat, square wave anodic stripping voltammetry

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Authors: Gülşah Çelik Gül, Figen Kurtuluş

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The first laboratory synthesis of hard materials such as diamond proceeded to attack of developing materials with high hardness to compete diamond. Boron rich solids are good candidates owing to their short interatomic bond lengths and strong covalent character. Boron containing hard material was synthesized by modified-microwave method under nitrogen atmosphere by using a fuel (glycine or urea), amorphous boron and/or boric acid in appropriate molar ratio. Characterizations were done by x-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy/energy dispersive analyze (SEM/EDS), thermo gravimetric/differantial thermal analysis (TG/DTA).

Keywords: boron containing materials, hard materials, microwave synthesis, powder X-ray diffraction

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Authors: Valentina Futoryanova, Hugh Hunt

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One of the common failure modes of the diesel engine turbochargers is high cycle fatigue of the turbine wheel blades. Mistuning of the blades due to the casting process is believed to contribute to the failure mode. Laser vibrometer is used to characterize mistuning for a population of turbine wheels through the analysis of the blade response to piezo speaker induced noise. The turbine wheel design under investigation is radial and is typically used in 6-12 L diesel engine applications. Amplitudes and resonance frequencies are reviewed and summarized. The study also includes test results for a paddle wheel that represents a perfectly tuned system and acts as a reference. Mass spring model is developed for the paddle wheel and the model suitability is tested against the actual data. Randomization is applied to the stiffness matrix to model the mistuning effect in the turbine wheels. Experimental data is shown to have good agreement with the model.

Keywords: vibration, radial turbines, mistuning, turbine blades, modal analysis, periodic structures, finite element

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Authors: Zineb Benouahmane, Zhang Lifeng

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Experimental oxidation tests at high temperature (1300°C-1500°C) on α-SiC samples have been performed with different holding times and atmosphere (air, argon). Oxidized samples were then analyzed using X-ray photoelectron spectroscopy coupled to SEM and DAKTEK surface profiler verification. The oxidation rate and the mas gain were found to increase with temperature and holding times, corresponding to a passive oxidation regime which lead to the formation of SiO2 layer. The sessile drop method is employed in order to measure the wetting angles between Si/SiC system at high temperature (1430°C-1550°C). Contact angle can be varied between 44 °C to 85°C, by controlling the oxygen content in α-SiC. Increasing the temperature occurred the infiltration of liquid silicon and deoxidation of the coating.

Keywords: oxidation, wettability, silicon, SiC

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Authors: Faraj M. Elkhatri, Hana Ali Allafi

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The spatial and temporal distribution of diagenetic alterations related impact on the reservoir quality of the Sarir Formation. (present day burial depth of about 9000 feet) Depositional facies and diagenetic alterations are the main controls on reservoir quality of Sarir Formation Sirt Ba-sin Libya; these based on lithology and grain size as well as authigenic clay mineral types and their distributions. However, petrology investigation obtained on study area with five sandstone wells concentrated on main rock components and the parameters that may have impacts on reservoirs. the main authigenic clay minerals are kaolinite and dickite, these investigations have confirmed by X.R.D analysis and clay fraction. mainly Kaolinite and Dickite were extensively presented on all of wells with high amounts. As well as trace of detrital smectite and less amounts of illitized mud-matrix are possibly find by SEM image. Thin layers of clay presented as clay-grain coatings in local depth interpreted as remains of dissolved clay matrix is partly transformed into kaolinite adjacent and towards pore throat. This also may have impacts on most of the pore throats of this sandstone which are open and relatively clean with some of fine martial have been formed on occluded pores. This material is identified by EDS analysis to be collections of not only kaolinite booklets, but also small, disaggregated kaolinite platelets derived from the dis-aggregation of larger kaolinite booklets. These patches of kaolinite not only fill this pore, but also coat some of the sur-rounding framework grains. Quartz grains often enlarged by authigenic quartz overgrowths partially occlude and re-duce porosity. Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM) was conducted on the post-test samples to examine any mud filtrate particles that may be in the pore throats. Semi-qualitative elemental data on select-ed minerals observed during the SEM study were obtained using an Energy Dispersive Spectroscopy (EDS) unit. The samples showed mostly clean open pore throats, with limited occlusion by kaolinite.

Keywords: por throat, formation damage, porosity lose, solids plugging

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Authors: Zdeněk Veselý, Milan Honner, Jiří Mach

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The aim of the performed work is to establish the 2D and 3D model of direct unsteady task of sample heat treatment by moving source employing computer model on the basis of finite element method. The complex boundary condition on heat loaded sample surface is the essential feature of the task. Computer model describes heat treatment of the sample during heat source movement over the sample surface. It is started from the 2D task of sample cross section as a basic model. Possibilities of extension from 2D to 3D task are discussed. The effect of the addition of third model dimension on the temperature distribution in the sample is showed. Comparison of various model parameters on the sample temperatures is observed. Influence of heat source motion on the depth of material heat treatment is shown for several velocities of the movement. Presented computer model is prepared for the utilization in laser treatment of machine parts.

Keywords: computer simulation, unsteady model, heat treatment, complex boundary condition, moving heat source

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Authors: Okba Belahssen, Lazhar Torchane, Said Benramache, Abdelouahed Chala

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This paper presents corrosion behavior of the plasma-nitrided 32CrMoV13 steel. Different kinds of samples were tested: non-treated, plasma nitrided samples. The structure of layers was determined by X-ray diffraction, while the morphology was observed by scanning electron microscopy (SEM). The corrosion behavior was evaluated by electrochemical techniques (potentiodynamic curves and electrochemical impedance spectroscopy). The corrosion tests were carried out in acid chloride solution (HCl 1M). Experimental results showed that the nitrides ε-Fe2−3N and γ′-Fe4N present in the white layer are nobler than the substrate but may promote, by galvanic effect, a localized corrosion through open porosity. The better corrosion protection was observed for nitrided sample.

Keywords: plasma-nitrided, 32CrMoV13 steel, corrosion, EIS

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Authors: Suraj D. Khadka, Priyantha W. Jayawickrama

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In search of a sustainable construction material, geopolymer has been investigated for past decades to evaluate its advantage over conventional products. Synthesis of geopolymer requires a source of aluminosilicate mixed with sodium hydroxide and sodium silicate at different proportions to maintain a Si/Al molar ratio of 1-3 and Na/Al molar ratio of unity. A comprehensive geopolymer study was performed with Metakaolin and Class C Fly ash as primary aluminosilicate sources. Synthesized geopolymer was analyzed for time-dependent viscosity, setting period and strength at varying initial moisture content, curing temperature and humidity. Different concentration of Ca(OH)₂ and CaSO₄.2H₂O were added to vary the amount of calcium contained in synthesized geopolymer. Influence of calcium content in unconfined compressive strength behavior of geopolymer were analyzed. Finally, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) was performed to investigate the hardened product. It was observed that fly ash based geopolymer had shortened setting time and faster increase in viscosity as compared to geopolymer synthesized from metakaolin. This was primarily attributed to higher calcium content resulting in formation of calcium silicate hydrates (CSH). SEM-EDS was performed to verify the presence of CSH phases. Spectral analysis of geopolymer prepared by addition of Ca(OH)₂ and CaSO₄.2H₂O indicated higher CSH phases at higher concentration. It was observed that lower concentration of added calcium favored strength gain in geopolymer. However, at higher calcium concentration, decrease in strength was observed. Strength variation was also observed with humidity at initial curing condition. At 100% humidity, geopolymer with added calcium presented higher strength compared to samples cured at ambient humidity condition (40%). Reduction in strength in these samples at lower humidity was primarily attributed to reduction in moisture content in specimen due to the formation of CSH phases and loss of moisture through evaporation. For low calcium content geopolymers, with increase in temperature, gain in strength was observed with maximum strength observed at 200 ˚C. However, samples with higher calcium content demonstrated severe cracking resulting in low strength at elevated temperatures.

Keywords: calcium silicate hydrates, geopolymer, humidity, Scanning Electron Microscopy-Energy Dispersive Spectroscopy, unconfined compressive strength

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Authors: Osagbai Joshua Eriki, Ngozi Agunwamba, Alice Hill, Lorna Almond, Maniya Duffy, Devashini Naidoo, David Ho, Raman Deo

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Aims: To evaluate the baseline eating pattern in a psychiatric hospital through quantifying purchases of food and drink items at the hospital shop and to implement a traffic light healthy eating labeling system. Method: A electronic till with reporting capabilities was purchased. A two-week period of baseline data collection was conducted. Thereafter, a system for labeling items based on the nutritional value of the food items at the hospital shop was implemented. Green labeling represented the items with the lowest calories and red the most. Further data was collated on the number and types of items purchased by patients according to the category, and the initial effectiveness of the system was evaluated. Result: Despite the implementation of the traffic light system, the red category had the highest number of items purchased by patients, highlighting the importance of promoting healthy eating choices. However, the study also showed that the system was effective in promoting healthy options, as the number of items purchased from the green category increased during the study period. Conclusion: The implementation of a traffic light labeling system for items sold at the hospital shop offers a promising approach to promoting healthy eating habits and choices. This is likely to contribute to a toolkit of measures when considering the multifactorial challenges that obesity and weight issues pose for long-stay psychiatric inpatients

Keywords: mental health, nutrition, food, healthy

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Authors: Mohamed Nasraoui

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Spatial ore distribution, ore heterogeneity and their links with geological processes involved in Niobium concentration are all factors for consideration when bridging field observations to extraction scheme. Indeed, mineralogy changes of Nb-hosting phases, their textural relationships with hydrothermal or secondary minerals, play a key control over mineral processing. This study based both on filed work and ore characterization presents data from several Nb-deposits related to carbonatite complexes. The results obtained by a wide range of analytical techniques, including, XRD, XRF, ICP-MS, SEM, Microprobe, Spectro-CL, FTIR-DTA and Mössbauer spectroscopy, demonstrate how geometallurgical assessment, at all stage of mine development, can greatly assist in the design of a suitable extraction flowsheet and data reconciliation.

Keywords: carbonatites, Nb-geometallurgy, Nb-mineralogy, mineral processing.

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Authors: A. Rabin, G. Mazor, I. Ladizhenski, R. Shneck, Z.

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The hardness and hardenability of AISI D2 cold work tool steel with conventional quenching (CQ), deep cryogenic quenching (DCQ) and rapid deep cryogenic quenching heat treatments caused by temporary porous coating based on magnesium sulfate was investigated. Each of the cooling processes was examined from the perspective of the full process efficiency, heat flux in the austenite-martensite transformation range followed by characterization of the temporary porous layer made of magnesium sulfate using confocal laser scanning microscopy (CLSM), surface and core hardness and hardenability using Vickr’s hardness technique. The results show that the cooling rate (CR) at the austenite-martensite transformation range have a high influence on the hardness of the studied steel.

Keywords: AISI D2, controllable cooling, magnesium sulfate coating, rapid cryogenic heat treatment, temporary porous layer

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Authors: Pauline Nyssen, Ange Mouithys-Mickalad, Maryse Hoebeke

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Inflammation is a complex physiological phenomenon involving chemical and enzymatic mechanisms. Polymorphonuclear neutrophil leukocytes (PMNs) play an important role by producing reactive oxygen species (ROS) and releasing myeloperoxidase (MPO), a pro-oxidant enzyme. Released both in the phagolysosome and the extracellular medium, MPO produces during its peroxidase and halogenation cycles oxidant species, including hypochlorous acid, involved in the destruction of pathogen agents, like bacteria or viruses. Inflammatory pathologies, like rheumatoid arthritis, atherosclerosis induce an excessive stimulation of the PMNs and, therefore, an uncontrolled release of ROS and MPO in the extracellular medium, causing severe damages to the surrounding tissues and biomolecules such as proteins, lipids, and DNA. The treatment of chronic inflammatory pathologies remains a challenge. For many years, MPO has been used as a target for the development of effective treatments. Numerous studies have been focused on the design of new drugs presenting more efficient MPO inhibitory properties. However, some designed inhibitors can be toxic. An alternative consists of assessing the potential inhibitory action of clinically-known molecules, having antioxidant activity. Propofol, 2,6-diisopropyl phenol, which is used as an intravenous anesthetic agent, meets these requirements. Besides its anesthetic action employed to induce a sedative state during surgery or in intensive care units, propofol and its injectable form Diprivan indeed present antioxidant properties and act as ROS and free radical scavengers. A study has also evidenced the ability of propofol to inhibit the formation of the neutrophil extracellular traps fibers, which are important to trap pathogen microorganisms during the inflammation process. The aim of this study was to investigate the potential inhibitory action mechanism of propofol and Diprivan on MPO activity. To go into the anti-inflammatory action of propofol in-depth, two of its oxidative derivatives, 2,6-diisopropyl-1,4-p-benzoquinone (PPFQ) and 3,5,3’,5’-tetra isopropyl-(4,4’)-diphenoquinone (PPFDQ), were studied regarding their inhibitory action. Specific immunological extraction followed by enzyme detection (SIEFED) and molecular modeling have evidenced the low anti-catalytic action of propofol. Stopped-flow absorption spectroscopy and direct MPO activity analysis have proved that propofol acts as a reversible MPO inhibitor by interacting as a reductive substrate in the peroxidase cycle and promoting the accumulation of redox compound II. Overall, Diprivan exhibited a weaker inhibitory action than the active molecule propofol. In contrast, PPFQ seemed to bind and obstruct the enzyme active site, preventing the trigger of the MPO oxidant cycles. PPFQ induced a better chlorination cycle inhibition at basic and neutral pH in comparison to propofol. PPFDQ did not show any MPO inhibition activity. The three interest molecules have also demonstrated their inhibition ability on an important step of the inflammation pathway, the PMNs superoxide anions production, thanks to EPR spectroscopy and chemiluminescence. In conclusion, propofol presents an interesting immunomodulatory activity by acting as a reductive substrate in the peroxidase cycle of MPO, slowing down its activity, whereas PPFQ acts more as an anti-catalytic substrate. Although PPFDQ has no impact on MPO, it can act on the inflammation process by inhibiting the superoxide anions production by PMNs.

Keywords: Diprivan, inhibitor, myeloperoxidase, propofol, spectroscopy

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Authors: G. Vinitha, A. Ramalingam

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In view of a possible application in optical data storage devices, diffraction grating efficiency of an organic dye, Acid Fuchsin doped in PMMA matrix was studied under excitation with CW diode pumped Nd: YAG laser at 532 nm. The open aperture Z-scan of dye doped polymer displayed saturable absorption and the closed aperture Z-scan of the samples exhibited negative nonlinearity. The diffraction efficiency of the grating is the ratio of the intensity of the first order diffracted power to the incident read beam power. The dye doped polymer films were found to be good media for recording. It is observed that the formation of gratings strongly depend on the concentration of dye in the polymer film, the intensity ratios of the writing beams and the angle between the writing beams. It has been found that efficient writing can be made at an angle of 20° and when the intensity ratio of the writing beams is unity.

Keywords: diffraction efficiency, nonlinear optical material, saturable absorption, surface-relief-gratings

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Authors: Eman A. Alghamdi, A. M. Aldhafiri

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It was found that the induce an isolated dopant close to the middle of the bandgap by occupying the Cd position in the CdTe lattice structure is an efficient factor in reducing the nonradiative recombination rate and increasing the solar efficiency. According to our laboratory results, this work has been carried out to obtain the effect of substrate temperature on the CdTe0.6Sn0.4 prepared by thermal evaporation technique for photovoltaic application. Various substrate temperature (25°C, 100°C, 150°C, 200°C, 250°C and 300°C) was applied. Sn-doped CdTe thin films on a glass substrate at a different substrate temperature were made using CdTe and SnTe powders by the thermal evaporation technique. The structural properties of the prepared samples were determined using Raman, x-Ray Diffraction. Spectroscopic ellipsometry and spectrophotometric measurements were conducted to extract the optical constants as a function of substrate temperature. The structural properties of the grown films show hexagonal and cubic mixed structures and phase change has been reported. Scanning electron microscopy (SEM) reviled that a homogenous with a bigger grain size was obtained at 250°C substrate temperature. The conductivity measurements were recorded as a function of substrate temperatures. The open-circuit voltage was improved by controlling the substrate temperature due to the improvement of the fundamental material issues such as recombination and low carrier concentration. All the result was explained and discussed on the biases of the influences of the Sn dopant and the substrate temperature on the structural, optical and photovoltaic characteristics.

Keywords: CdTe, conductivity, photovoltaic, ellipsometry

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Authors: Oranso T. Mahlangi, Bhekie B. Mamba

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The occurrence of trace organic compounds (TOrCs) in water has raised health concerns for living organisms. The majority of TorCs, including pharmaceuticals and volatile organic compounds, are poorly monitored, partly due to the high cost of analysis and less strict water quality guidelines in South Africa. Therefore, the removal of TorCs is important to guarantee safe potable water. In this study, ZnO nanoparticles were fabricated in situ in polyethersulfone (PES) polymer solutions. This was followed by membrane synthesis using the phase inversion technique. Techniques such as FTIR, Raman, SEM, AFM, EDS, and contact angle measurements were used to characterize the membranes for several physicochemical properties. The membranes were then evaluated for their efficiency in treating pharmaceutical wastewater and resistance to organic (sodium alginate) and protein (bovine serum albumin) fouling. EDS micrographs revealed uniform distribution of ZnO nanoparticles within the polymer matrix, while SEM images showed uniform fingerlike structures. The addition of ZnO increased membrane roughness as well as hydrophilicity (which in turn improved water fluxes). The membranes poorly rejected monovalent and divalent salts (< 10%), making them resistant to flux decline due to concentration polarization effects. However, the membranes effectively removed carbamazepine, caffeine, sulfamethoxazole, ibuprofen, and naproxen by over 50%. ZnO PES membranes were resistant to organic and protein fouling compared to the neat membrane. ZnO PES ultrafiltration membranes may provide a solution in the reclamation of wastewater.

Keywords: trace organic compounds, pharmaceuticals, membrane fouling, wastewater reclamation

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Authors: Sajmina Khatun, Monika Pebam, Aravind Kumar Rengan

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Photothermal therapy, a subset of nanomedicine, takes advantage of light-absorbing agents to generate localized heat, selectively eradicating cancer cells. This innovative approach minimizes damage to healthy tissues and offers a promising avenue for targeted cancer treatment. Unlike conventional therapies, photothermal therapy harnesses the power of light to combat malignancies precisely and effectively, showcasing its potential to revolutionize cancer treatment paradigms. The combined strengths of nanomedicine and photothermal therapy signify a transformative shift toward more effective, targeted, and tolerable cancer treatments in the medical landscape. Utilizing natural products becomes instrumental in formulating diverse bioactive medications owing to their various pharmacological properties attributed to the existence of phenolic structures, triterpenoids, and similar compounds. Hyptis suaveolens, commonly known as pignut, stands as an aromatic herb within the Lamiaceae family and represents a valuable therapeutic plant. Flourishing in swamps and alongside tropical and subtropical roadsides, these noxious weeds impede the development of adjacent plants. Hyptis suaveolens ranks among the most globally distributed alien invasive species. The present investigation revealed that a versatile, biodegradable liposome nanosystem (HIL NPs), incorporating bioactive molecules from Hyptis suaveolens, exhibits effective bioavailability to cancer cells, enabling tumor ablation upon near-infrared (NIR) laser exposure. The components within the nanosystem, specifically the bioactive molecules from Hyptis, function as anticancer agents, aiding in the photothermal ablation of highly metastatic lung cancer cells. Despite being a prolific weed impeding neighboring plant growth, Hyptis suaveolens showcases therapeutic benefits through its bioactive compounds. The obtained HIL NPs, characterized as a photothermally active liposome nanosystem, demonstrate a pronounced fluorescence absorption peak in the NIR range and achieve a high photothermal conversion efficiency under NIR laser irradiation. Transmission electron microscopy (TEM) and particle size analysis reveal that HIL NPs possess a spherical shape with a size of 141 ± 30 nm. Moreover, in vitro assessments of HIL NPs against lung cancer cell lines (A549) indicate effective anticancer activity through a combined cytotoxic effect and hyperthermia. Tumor ablation is facilitated by apoptosis induced by the overexpression of ɣ-H2AX, arresting cancer cell proliferation. Consequently, the multifunctional and biodegradable nanosystem (HIL NPs), incorporating bioactive compounds from Hyptis, provides valuable perspectives for developing an innovative therapeutic strategy originating from a challenging weed. This approach holds promise for potential applications in both bioimaging and the combined use of phyto-photothermal therapy for cancer treatment.

Keywords: bioactive liposome, hyptis suaveolens, photothermal therapy, lung cancer

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Authors: S. Benzitouni, M. Zaabat, A. Mahdjoub, A. Benaboud, T.Saidani ‎

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To improve the physical properties of ZnO nanostructures textured (103) by sol-gel ‎dip coating method, Al and In are used as dopant with different weight ratios (5%, 10%). ‎The comparative study between Al doped ZnO thin films (AZO) and In doped ZnO (IZO) ‎are made by different analysis technic. XRD showed that the films are Pollycristallins with ‎hexagonal wûrtzite structure and preferred orientation (002) and (103). UV-Vis ‎spectroscopy showed that all films have a high transmission (> 85%); the interference ‎fringes are only observed for IZO. The optical gap is reduced due to the introduction of In ‎‎(minimum value is 3.12 eV), but increased in the presence of Al (maximum value is 3.34 ‎eV). The thickness of the layers was obtained by modeling (using Forouhi Bloomer ‎method). AFM used to observe the surface texture of the films and determined grain size ‎and surface roughness (RMS) which varies in a small range [3.14 to 1.25] nm‎.

Keywords: ZnO, optical gap, roughness (RMS), nanostructures‎

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Authors: Kwangin Kim, Taewon Yoo, Haksoo Han

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Polyimide is a superior polymer in the electronics industry, and we conducted a study to synthesize poly(amide-imide) at low temperatures. Poly(amide-imide) was synthesized at low-temperature curing to offer a thermal stable membrane with low residual stress and good processability. As a result, the low crack polymer with good processability could be used to various applications such as semiconductors, integrated circuits, coating materials, membranes, and display. The synthesis of poly(amide-imide) at low temperatures was confirmed by Fourier transform infrared spectroscopy (FT-IR). Thermal stabilities of the polymer was confirmed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).

Keywords: poly(amide-imide), residual stress, thermal stability

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Authors: Harish Kuruva, Vedasri Bai Khavala, Tiju Thomas, K. Murugan, B. S. Murty

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Industries are growing day to day to increase the economy of the country. The biggest problem with industries is wastewater treatment. Releasing these wastewater directly into the river is more harmful to human life and a threat to aquatic life. These industrial effluents contain many dissolved solids, organic/inorganic compounds, salts, toxic metals, etc. Phenols, pesticides, dioxins, herbicides, pharmaceuticals, and textile dyes were the types of industrial effluents and more challenging to degrade eco-friendly. So many advanced techniques like electrochemical, oxidation process, and valorization have been applied for industrial wastewater treatment, but these are not cost-effective. Industrial effluent degradation is complicated compared to commercially available pollutants (dyes) like methylene blue, methylene orange, rhodamine B, etc. TiO₂ is one of the widely used photocatalysts which can degrade organic compounds using solar light and moisture available in the environment (organic compounds converted to CO₂ and H₂O). TiO₂ is widely studied in photocatalysis because of its low cost, non-toxic, high availability, and chemically and physically stable in the atmosphere. This study mainly focused on valorizing the mineralogical product TiO₂ (IREL, India). This mineralogical graded TiO₂ was characterized and compared with its structural and photocatalytic properties (industrial effluent degradation) with the commercially available Degussa P-25 TiO₂. It was testified that this mineralogical TiO₂ has the best photocatalytic properties (particle shape - spherical, size - 30±5 nm, surface area - 98.19 m²/g, bandgap - 3.2 eV, phase - 95% anatase, and 5% rutile). The industrial effluent was characterized by TDS (total dissolved solids), ICP-OES (inductively coupled plasma – optical emission spectroscopy), CHNS (Carbon, Hydrogen, Nitrogen, and sulfur) analyzer, and FT-IR (fourier-transform infrared spectroscopy). It was observed that it contains high sulfur (S=11.37±0.15%), organic compounds (C=4±0.1%, H=70.25±0.1%, N=10±0.1%), heavy metals, and other dissolved solids (60 g/L). However, the organo-sulfur industrial effluent was degraded by photocatalysis with the industrial mineralogical product TiO₂. In this study, the industrial effluent pH value (2.5 to 10), catalyst concentration (50 to 150 mg) were varied, and effluent concentration (0.5 Abs) and light exposure time (2 h) were maintained constant. The best degradation is about 80% of industrial effluent was achieved at pH 5 with a concentration of 150 mg - TiO₂. The FT-IR results and CHNS analyzer confirmed that the sulfur and organic compounds were degraded.

Keywords: wastewater treatment, industrial mineralogical product TiO₂, photocatalysis, organo-sulfur industrial effluent

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Authors: Van Tran Thi Thuy, Dukjoon Kim

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A series of pH- and thermosensitive poly(N-isopropyl acrylamide-co-acrylic acid) were synthesized by radical polymerization and grafted on poly succinimide backbones. The poly succinimide derivatives synthesized were coated on iron oxide magnetic nanoparticles for potential applications in drug delivery systems with theranostic and molecular imaging. The structure of polymer shell was confirmed by FT-IR, H-NMR spectroscopies. Its thermal behavior was tested by UV-Vis spectroscopy. The particle size and its distribution are measured by dynamic light scattering (DLS) and transmission electron microscope (TEM). The mean diameter of the core-shell structure is from 20 to 80 nm.

Keywords: magnetic, nano, PNIPAM, polysuccinimide

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Authors: Mingmei Zhang, Xinyong Li

Abstract:

AgInS₂/SnS₂ (AIS) nanocomposites were synthesized by a simple hydrothermal method. The morphology and composition of the fabricated AIS nanocomposites were investigated by field-emission scanning electron microscopy (SEM), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Moreover, the as-prepared AIS photocatalysts exhibited excellent photocatalytic activities for the degradation of Norfloxacin (NOR), mainly due to its high optical absorption and separation efficiency of photogenerated electron-hole pairs, as evidenced by UV–vis diffusion reflection spectra (DRS) and Surface photovoltage (SPV) spectra. Furthermore, the interfacial charges transfer mechanism was also discussed by DFT calculations.

Keywords: AIS nanocomposites, electron-hole pairs, charges transfer, DFTcaculations

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Authors: Raghuram Kandimalla, Sanjeeb Kalita, Bhaswati Choudhury, Jibon Kotoky

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The quest for developing an ideal suture material prompted our interest to develop a novel suture with advantageous characteristics to market available ones. We developed novel suture biomaterial from muga silk (Antheraea assama) and ramie (Boehmeria nivea) plant fiber. Field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) and thermo gravimetric analysis (TGA) results revealed the physicochemical properties of the fibers which supports the suitability of fibers for suture fabrication. Tensile properties of the prepared sutures were comparable with market available sutures and it found to be biocompatible towards human erythrocytes and nontoxic to mammalian cells. The prepared sutures completely healed the superficial deep wound incisions within seven days in adult male wister rats leaving no rash and scar. Histopathology studies supports the wound healing ability of sutures, as rapid synthesis of collagen, connective tissue and other skin adnexal structures were observed within seven days of surgery. Further muga suture surface modified by exposing the suture to oxygen plasma which resulted in formation of nanotopography on suture surface. Broad spectrum antibiotic amoxicillin was functionalized on the suture surface to prepare an advanced antimicrobial muga suture. Surface hydrophilicity induced by oxygen plasma results in an increase in drug-impregnation efficiency of modified muga suture by 16.7%. In vitro drug release profiles showed continuous and prolonged release of amoxicillin from suture up to 336 hours. The advanced muga suture proves to be effective against growth inhibition of Staphylococcus aureus and Escherichia coli, whereas normal muga suture offers no antibacterial activity against both types of bacteria. In vivo histopathology studies and colony-forming unit count data revealed accelerated wound healing activity of advanced suture over normal one through rapid synthesis and proliferation of collagen, hair follicle and connective tissues.

Keywords: sutures, biomaterials, silk, Ramie

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Authors: I. Irska, S. Paszkiewicz, D. Pawlikowska, E. Piesowicz, A. Linares, T. A. Ezquerra

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Due to the number of advantages such as high tensile strength, sensitivity to hydrolytic degradation, and biocompatibility poly(lactic acid) (PLA) is one of the most common polyesters for biomedical and pharmaceutical applications. However, PLA is a rigid, brittle polymer with low heat distortion temperature and slow crystallization rate. In order to broaden the range of PLA applications, it is necessary to improve these properties. In recent years a number of new strategies have been evolved to obtain PLA-based materials with improved characteristics, including manipulation of crystallinity, plasticization, blending, and incorporation into block copolymers. Among the other methods, synthesis of aliphatic-aromatic copolyesters has been attracting considerable attention as they may combine the mechanical performance of aromatic polyesters with biodegradability known from aliphatic ones. Given the need for highly flexible biodegradable polymers, in this contribution, a series of aromatic-aliphatic based on poly(butylene terephthalate) and poly(lactic acid) (PBT-b-PLA) copolyesters exhibiting superior mechanical properties were copolymerized with an additional poly(tetramethylene oxide) (PTMO) soft block. The structure and properties of both series were characterized by means of attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR), nuclear magnetic resonance spectroscopy (¹H NMR), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS) and dynamic mechanical, thermal analysis (DMTA). Moreover, the related changes in tensile properties have been evaluated and discussed. Lastly, the viscoelastic properties of synthesized poly(ester-ether) copolymers were investigated in detail by step cycle tensile tests. The block lengths decreased with the advance of treatment, and the block-random diblock terpolymers of (PBT-ran-PLA)-b-PTMO were obtained. DSC and DMTA analysis confirmed unambiguously that synthesized poly(ester-ether) copolymers are microphase-separated systems. The introduction of polyether co-units resulted in a decrease in crystallinity degree and melting temperature. X-ray diffraction patterns revealed that only PBT blocks are able to crystallize. The mechanical properties of (PBT-ran-PLA)-b-PTMO copolymers are a result of a unique arrangement of immiscible hard and soft blocks, providing both strength and elasticity.

Keywords: aliphatic-aromatic copolymers, multiblock copolymers, phase behavior, thermoplastic elastomers

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Authors: Elise M. Shauf

Abstract:

Beryllium can be found naturally in some fruits and vegetables (carrots, garden peas, kidney beans, pears) at very low concentrations, but is typically not clinically significant due to the low-level exposure and limited absorption of beryllium by the stomach and intestines. However, acute or chronic beryllium exposure can result in harmful toxic and carcinogenic biological effects. Beryllium can be both a workplace hazard and an environmental pollutant, therefore determining the presence of beryllium at trace levels can be essential to protect workers as well as the environment. Analysis of gallein, C₂₀H₁₂O₇, to determine if it is usable as a fluorescent dye for beryllium detection. The primary detection method currently in use includes hydroxybenzoquinoline sulfonates (HBQS), for which alternative indicators are desired. Unfortunately, gallein does not have the desired aspects needed as a dye for beryllium detection due to the peak shift properties.

Keywords: beryllium detection, fluorescent, gallein dye, indicator, spectroscopy

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Authors: Masauso Moses Phiri

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Frequent glucose monitoring is essential to the management of diabetes. Plasmonic enzyme-based glucose biosensors have the advantages of greater specificity, simplicity and rapidity. The aim of this study was to develop a rapid plasmonic colorimetric glucose biosensor based on biocatalytic enlargement of AuNS guided by GOx. Gold nanoparticles of 18 nm in diameter were synthesized using the citrate method. Using these as seeds, a modified seeded method for the synthesis of monodispersed gold nanostars was followed. Both the spherical and star-shaped nanoparticles were characterized using ultra-violet visible spectroscopy, agarose gel electrophoresis, dynamic light scattering, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. The feasibility of a plasmonic colorimetric assay through growth of AuNS by silver coating in the presence of hydrogen peroxide was investigated by several control and optimization experiments. Conditions for excellent sensing such as the concentration of the detection solution in the presence of 20 µL AuNS, 10 mM of 2-(N-morpholino) ethanesulfonic acid (MES), ammonia and hydrogen peroxide were optimized. Using the optimized conditions, the glucose assay was developed by adding 5mM of GOx to the solution and varying concentrations of glucose to it. Kinetic readings, as well as color changes, were observed. The results showed that the absorbance values of the AuNS were blue shifting and increasing as the concentration of glucose was elevated. Control experiments indicated no growth of AuNS in the absence of GOx, glucose or molecular O₂. Increased glucose concentration led to an enhanced growth of AuNS. The detection of glucose was also done by naked-eye. The color development was near complete in ± 10 minutes. The kinetic readings which were monitored at 450 and 560 nm showed that the assay could discriminate between different concentrations of glucose by ± 50 seconds and near complete at ± 120 seconds. A calibration curve for the qualitative measurement of glucose was derived. The magnitude of wavelength shifts and absorbance values increased concomitantly with glucose concentrations until 90 µg/mL. Beyond that, it leveled off. The lowest amount of glucose that could produce a blue shift in the localized surface plasmon resonance (LSPR) absorption maxima was found to be 10 – 90 µg/mL. The limit of detection was 0.12 µg/mL. This enabled the construction of a direct sensitivity plasmonic colorimetric detection of glucose using AuNS that was rapid, sensitive and cost-effective with naked-eye detection. It has great potential for transfer of technology for point-of-care devices.

Keywords: colorimetric, gold nanostars, glucose, glucose oxidase, plasmonic

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Authors: Mahendrasingh J. Pawar, M. D. Gaoner

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Ta-doped Nb2O5 (Ta content 0.5-2% mole fraction) nanoparticles in the range of 20-40 nm were synthesized by combustion technique. The crystalline phase, morphology and size of the nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. The specific surface area of the nanoparticles was measured by nitrogen adsorption (BET analysis). The undoped Nb2O5 nanoparticles were found to have the particles size in the range of 50−80 nm. The photocatalytic performance of the samples was characterized by degrading 20 mg/L toluene under UV−Vis irradiation. The results show that the Ta-doped Nb2O5 nanoparticles exhibit a significant increase in photocatalytic performance over the undoped Nb2O5 nanoparticles, and the Nb2O5 nanoparticles doped with 1.5% Ta and calcined at 450°C show the best photocatalytic performance.

Keywords: Nb2O5, Ta-doped Nb2O5, photodegradation of Toluene, combustion method

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Authors: Andrei Bejan, Luminita Marin, Dalila Belei

Abstract:

Phenothiazine with electron-rich nitrogen and sulfur heteroatoms has a high electron-donating ability which promotes a good conjugation and therefore low band-gap with consequences upon charge carrier mobility improving and shifting of light emission in visible domain. Moreover, its non-planar butterfly conformation inhibits molecular aggregation and thus preserves quite well the fluorescence quantum yield in solid state compared to solution. Therefore phenothiazine and its derivatives are promising hole transport materials for use in organic electronic and optoelectronic devices as light emitting diodes, photovoltaic cells, integrated circuit sensors or driving circuits for large area display devices. The objective of this paper was to obtain a series of new phenothiazine derivatives by introduction of different electron withdrawing substituents as formyl, carboxyl and cyanoacryl units in order to create a push pull system which has potential to improve the electronic and optical properties. Bromine atom was used as electrono-donor moiety to extend furthermore the existing conjugation. The understudy compounds were structural characterized by FTIR and 1H-NMR spectroscopy and single crystal X-ray diffraction. Besides, the single crystal X-ray diffraction brought information regarding the supramolecular architecture of the compounds. Photophysical properties were monitored by UV-vis and photoluminescence spectroscopy, while the electrochemical behavior was established by cyclic voltammetry. The absorption maxima of the studied compounds vary in a large range (322-455 nm), reflecting the different electronic delocalization degree, depending by the substituent nature. In a similar manner, the emission spectra reveal different color of emitted light, a red shift being evident for the groups with higher electron withdrawing ability. The emitted light is pure and saturated for the compounds containing strong withdrawing formyl or cyanoacryl units and reach the highest quantum yield of 71% for the compound containing bromine and cyanoacrilic units. Electrochemical study show reversible oxidative and reduction processes for all the compounds and a close correlation of the HOMO-LUMO band gap with substituent nature. All these findings suggest the obtained compounds as promising materials for optoelectronic devices.

Keywords: electrochemical properties, phenothiazine derivatives, photoluminescence, quantum yield

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