Scanning Electron Microscopy Studies Research Articles

Evaluation of canal cleanliness of two rotary file systems with different taper systems: An in vitro scanning electron microscopic study

Evaluation of canal cleanliness of two rotary file systems with different taper systems: An in vitro scanning electron microscopic study

New data on the morphology of Ascarophis parupenei (Nematoda: Cystidicolidae), an intestinal parasite of the marine fish Parupeneus indicus in the Indian Ocean, revealed by SEM.

Scanning electron microscopy studies of three paratype specimens (two males and one female) of Ascarophis parupenei Moravec, Orecchia & Paggi, 1988, an intestinal parasite of the marine fish Parupeneus indicus (Shaw) in the Indian Ocean, made it possible to redescribe in detail the cephalic structures of this nematode as well as the morphology of the male caudal end. The presence of non-bilobed sublabia, phasmids in both males and females, bifurcated deirids, well-developed precloacal cuticular ridges (area rugosa) and a ventral median caudal protuberance in the male are reported in this species for the first time. The general morphology and measurements of A. parupenei somewhat resemble those of Rasheedia novaecaledoniensis Moravec & Justine, 2018 described from the same host species (P. indicus) from off New Caledonia, but both species clearly differ from each other by the shape and structure of pseudolabia and the anterior portion of the digestive tract, belonging thus to different nematode families (Cystidicolidae and Physalopteridae, respectively).

Green Synthesis of Nanomaterials with Phytochemicals for Treating Multidrug Resistant Bacteria

The Bacteria with Multidrug resistance and Extreme drug resistance are increasing at a rapid rate. Various methods have been employed to combat drug resistant bacteria. Major classes of antibiotics aren’t effective against these bacteria. Alternative methods have been studied in recent years. Nanoparticles are used against multidrug resistant bacteria; The green synthesized nanoparticles are more reliable due to more shelf life and lesser toxicity relative to chemically synthesized nanoparticles. Multi drug resistant E. coli and Staphylococcus aureus was isolated from sewage samples. Green synthesized nanoparticles from various plants samples have been prepared with Zinc and Copper forming respective oxides with Neem, Nakara, Jatropha, Mango, Clove, Ginger, Cardamom, Cinnamon and Betel against multidrug resistant Escherichia coli and Staphylococcus aureus. Isolated E. coli was susceptible to Fluoroquinolone and Augmentin whereas S. aureus was susceptible to vancomycin. Green synthesized nanoparticles had more antimicrobial activity against E. coli and S. aureus than chemically synthesized nanoparticles and plant extracts. Green synthesized Nakara CuO nano particles had inhibition zone of 31 ±0.6mm and 30 ±0.7mm for E. coli and S. aureus respectively, ZnO nano particles of Nakara had 25 ±0.6mm inhibition zone for E. coli and S. aureus. Green synthesized Jatropha CuO nano particles had inhibition zone of 26 ±0.5 and 26 ±0.4mm for E. coli and S. aureus. ZnO nano particles of Jatropha had 31±0.7mm and 30±0.7mm inhibition zone for E. coli and S. aureus respectively. The Scanning electron microscopy studies revealed 26nm Jatropha ZnO and 25nm Nakara CuO nanoparticles. Nano materials were found to be non-toxic in cell line studies. The present study concludes to study the impact of green synthesized nanoparticles as an alternative to antibiotics to combat multidrug resistant bacteria.

Growth, Characterizations of Aspartame-ASP Crystals for Mechano, Spectral, Photonic, Opto-Electronic and Sensor Applications

The organic crystal has prevalent outcome and Aspartame-ASP crystal which is in anhydrate form is of 160–200 times sweeter than the sucrose and the single crystalline X-ray diffraction (XRD) data for ASP are a, b, c in Å as 19.4077, 4.9604, 15.6547, and alpha and gamma as 90°, beta as 94.877° and system is monoclinic, the space group is P21. The XRD reveals the monoclinic arrangement of the ASP crystal, the UV effect with Tauc’s plot for lower frequency cut off at 295 nm and band gap as 4.203 eV, morphology by scanning electron microscopy study in μm scaling, Vicker’s proviso by hardness profile, basic functional groups by Fourier transform infrared and basic examinations, excitation—emission by PhotoLuminescence-PL peak at 513 nm, electronic sort of ASP filters in 4.3275 microns, electric depiction by dielectric study and mechano use by hardness profile of ASP are studied and reported. Hardness coefficient by Vicker’s intended for ASP with n as 2.91. The NLO-SHG is of 1.76 times KDP with phase matched effect of ASP is reported. Also, the room-temperature sensor study of ASP is measured and compliance by red light-emitting diode source.

Trichoderma harzianum TIND02 upregulates the expression of pathogenesis-related genes and enzymes and enhances gray blight resistance in tea

The gray blight incited by Pestalotiopsis and allied genera is a prevalent disease affecting tea cultivation, and managing it with Trichoderma spp. is an alternative to synthetic fungicides. Plants modify their arsenal system against pathogens when they are exposed to Trichoderma spp., which produces proteins and enzymes associated with pathogenesis. Understanding the expression pattern of defense-related markers will help in developing gray blight resistance tea cultivars. Thus, this study intended to induce resistance against gray blight in tea by Trichoderma harzianum TIND02. For this, a total of eight Trichoderma isolates originated from organic tea rhizospheres were characterized and evaluated for their efficacy. Dual culture test revealed isolate TIND02 as the most potential candidate with 74.6% inhibitory activity against gray blight pathogen Pseudopestalotiopsis theae. Molecular characterization based on ITS and tef-1 alpha genes confirmed isolate TIND02 as T. harzianum. Scanning electron microscopic study showed the mycoparasitic nature of T. harzianum TIND02 (TH-TIND02) to Ps. theae. The ethyl acetate extract of TH-TIND02 at 100 and 200 μg mL−1 showed potential inhibitory activity (>69.9%) against Ps. theae which confirmed the presence of higher volatile metabolites. Gas chromatography–Mass spectrometry study revealed that ethyl acetate extract of TH-TIND02 was composed of 21 major and minor volatile organic compounds with acetamide, 2, 2, 2-trifluoro-N, N-bis trimethyIsilyl–C (94.74%) as a major component. The isolate also produced chitinase, cellulase, β-1, 3 glucanase, and protease hydrolytic enzymes. Nursery experiments revealed that 2% and 5% doses (2 × 106 CFU mL−1) of TH-TIND02 significantly reduced respective 65.0% and 70.0% disease severity over control with improved plant growth. Besides, expressions of defense-related enzymes (chitinase, pHenolics, peroxidase, phenylalanine ammonia lyase, β-1, 3-glucanase, and polyphenol oxidase) and pathogenesis-related genes (chitinase and β-1, 3-glucanase) due to TH-TIND02 were determined. The secretion of defense-related enzymes was highly upregulated in plants applied with TH-TIND02 followed by Ps. theae inoculation compared to controls. The RT-qPCR analysis showed that the expression of both genes in co-inoculated plants was two-fold higher than in control after 21-day post incubation. These results suggest that TH-TIND02 application reduced gray blight severity by elevated enzyme activity and overexpressed pathogenesis-related genes in tea plants which offer for its eco-friendly and sustainable use as a bio-fungicide in tea gardens.

Synthesis, Studies of HDTDHP-μ Crystals from Arundina graminifolia Specimen for Electronic, Photonic, Optical and Electrical Use Correlated with Macro-Crystals for Sensor and Display Uses

A 7-hydroxy-2,4-dimethoxy-9,10-dihydrophenanthrene-HDTDHP macro-crystalline sample is synthesized in a time duration of 23 days with a monoclinic form of crystal with space group as P21/n and the lattice constants are slightly higher than earlier reported macro-HDTDHP. The macro ones are well-milled to get the micro ones and a scanning electron microscopy study of the HDTDHP-μ crystal was analyzed to identify the micro level average scaling in microns. The increased value of the dielectric constant at lower range of frequencies is by the effect of all kinds of polarizations; also, the dielectric loss is measured as decrease in values with the increase in frequencies at room temperature. The electronic-micro filter use is 4.0196 microns for micro influx as the proper opto-electronic, extended NLO type employability as ascertained from transmittance spectral data. The HDTDHP micro-crystalline material is mainly used in micro-photonics, in filtering as micro-influx delineation, in NLO usefulness as opto-electronic agent by the transmittance data and in frequency enhancing and projective utilization in displays. Also, display profile of (111) mode of HDTDHP by without and with recursively assigned colors for RGBR polygonal matrix by software and sensor work sensitiveness of both scaling are measured and reported.

Hydrothermally grown copper cobalt phosphate hydrate nanostars for supercapacitors: Investigation of their charge transfer kinetics

The transition bimetal phosphates are optimistic materials for supercapacitors. In this study, copper cobalt phosphate hydrate ((Cu0.35Co0.65)3(PO4)2·H2O) (CCPH) was deposited on Nickel foam using a hydrothermal method at different reaction temperatures as 120, 150, and 180 °C. X-ray diffraction analysis results in the monoclinic crystal structure of CCPH. The Raman study confirms the presence of the phosphate group. The scanning electron microscopy (SEM) study reveals that the reaction temperature-dependent morphological evolution takes place from nanostars to three dimensional (3D)-porous spongy balls-like structure. The elevating reaction temperature has changed the morphology from nanostars to 3D-porous spongy balls. The electrochemical analysis of the CCPH12 electrode resulted in a specific capacitance of 3390.73 mF/cm2 (518.02 µAh/cm2) at 10 mA/cm2 current density. The charge storage dynamics of the CCPH electrodes were analyzed using power law. The CCPH12 electrode delivered the energy density and power density as 0.142 mWh/cm2 and 2.75 mW/cm2, respectively.

Spirulina platensis as a super prebiotic to enhance the antibacterial effect of Lactobacillus casei

Microalgae are diminutive unicellular magnificent creatures that exist in the microscopic form. Within this classification, two notable subtypes, namely Spirulina platensis and Chlorella vulgaris, have garnered significant attention. S. platensis is mostly known for its therapeutic benefits due to proteins, vitamins, essential amino acids, minerals, and essential fatty acids abundance.The subsequent work aimed to investigate the prebiotic effect of S. platensis enhancing Lactobacillus casei microbiome growth rate and antibacterial effect. Different concentrations of S. platensis were prepared (0, 0.5, 5, and 50 mg/mL) then co-cultured with L. casei. Live probiotic enumeration, molecular characterization and scanning electron microscopy studies were performed. Data revealed that 5 mg/mL of S. platensis significantly enhanced the probiotic live count and consequently the antibacterial activity. The antibacterial and antibiofilm effects of L. casei/S. platensis mixture showed complete inhibition to the growth of bacterial cells after 4- and 8-h incubation with Staphylococcus epidermidis 12228 and Escherichia coli 25922, respectively. Moreover, minimal biofilm eradication concentration (MBEC) value of 16 µg/mL was recorded for L. casei/S. platensis mixture

Effect of sodium dodecyl sulfate on the dielectric and electrical properties of poly (vinylidene fluoride)-zinc ferrite composites

Polymer composites comprising Poly (vinylidene fluoride) (PVDF) as a matrix, Zinc Ferrite (ZnFe2O4: ZFO) as ceramic filler and Sodium Dodecyl Sulfate (SDS) as a surface modifying agent have been synthesized through a simple solvent casting route for application in energy storage devices. The Scanning Electron Microscopic (SEM) study confirmed that the surface modification through Sodium Dodecyl Sulphate improved the dispersion of ZFO particles in the PVDF matrix. The FTIR Spectrophotometer study revealed the existence of expected functional groups in the modified composites The advantage of treatment of SDS on the composite obtained from blending of PVDF with Zinc Ferrite was investigated. The Impedance Analyzer study indicated that the composite with 1.5 wt.% Zinc Ferrite nanoparticles encapsulated by SDS exhibited the highest dielectric constant and reduced loss tangent. In addition, the experimental values of the dielectric constant were compared with some theoretical models. Further, the PE loop study showed higher remanent polarisation in the 1.5 wt.% SDS treated composite indicating that treatment of SDS on Zinc Ferrite (ZFO) can be adopted to fabricate composites for high energy storage applications.

Investigation of pollen morphology and viability of sweet and sour cherry genotypes by multivariate analysis.

The aim of this study was to examine the dimensions and surface morphology of pollen grains of some sweet and sour cherry genotypes through scanning electron microscopy (SEM) as an additional alternative identification tool. In vitro pollen germination and pollen tube length as indicators of their viability were determined as well. Observations were carried on 10 sweet cherry (Prunus avium L.) and 7 sour cherry (Prunus cerasus L.) genotypes. All genotypes had prolate, tricolpate pollen grains, and striate exine ornamentation, with more parallel longitudinal ridges. Significant differences among genotypes within species and between species were found for most pollen grain characteristics and exine ornamentation. In both sweet and sour cherry the largest variability was recorded for colpus length (CV = 15.0% and 12.9%, respectively). For sweet cherry genotypes, in vitro pollen germination and pollen tube length ranged between 1.4% to 51.5% and 360.4 to 669.3 μm respectively, while for sour cherries they ranged from 15.5% to 37.0% and 96.3 to 960.2 μm, respectively. The results of the correlation analysis showed that in vitro pollen germination correlated positively with pollen length/pollen width (L/W) ratio (r = .640) and furrow width (r = .588), and negatively with the number of ridges (r = -.517), while pollen tube length was not significantly correlated with any of the studied characteristics. Principal component analysis (PCA) revealed that pollen length, pollen width, L/W ratio, colpus length, mesocolpium width, and ridge width are relevant tools to discriminate among the studied genotypes. The measurements made on pollen grains did not reveal individually big differences, but when all features were considered together, the pollen of each genotype exhibited a unique pattern. The distribution on the scatter plot showed considerable variation among sweet and sour cherry genotypes based on pollen morphological characteristics, which led to their distribution into two separate groups. This demonstrates the ability to distinguish cherry species based on pollen morphological characteristics determined by SEM. To improve discriminative ability for genotypes within species combination between pollen ultrastructural analysis, morphological and molecular markers is desirable, in subsequent work. RESEARCH HIGHLIGHTS: Significant differences in pollen characteristics between sweet and sour cherry. Significance of pollen morphology in taxonomic differentiation. Significance of SEM studies for the taxonomic identification.

Hesperetin regulates PI3K/Akt and mTOR pathways to exhibit its antiproliferative effect against colon cancer cells

ABSTRACT Hesperetin, a citrus flavonoid, has been a widely studied anticancer agent against many types of cancers, but the exact mechanism of efficacy is still unrevealed. Therefore, this study has attempted to delineate the mechanical aspect of hesperetin’s anticancer efficacy against colon cancer using immunoblotting, scanning, and transmission electron microscopic studies. The treatment with hesperetin (25 and 50 µM) has significantly (p < 0.0001) curbed down the proliferation and cell viability of HCT-15 cells in a concentration as well as time dependent manner. Hesperetin was able to achieve this through the induction of caspase-dependent apoptosis. Moreover, hesperetin effectively inhibited phosphorylation of Akt with a parallel increase in PTEN expression thereby inhibiting the PI3K signaling axis, which contributes to the suppression of proliferation. In addition, hesperetin enhanced autophagy through dephosphorylating mTOR, one of the downstream targets of Akt with simultaneous acceleration in Beclin-1 and LC3-II expression levels. Interestingly, hesperetin enhanced the effects of Akt inhibitor LY294002 and mTOR inhibitor rapamycin. This study documented the potential of hesperetin to induce apoptosis through simultaneous acceleration over the autophagic process in colon cancer cells. Thus, hesperetin played a beneficial therapeutic role in preventing colon carcinoma growth by regulating the Akt and mTOR signaling axis.

The investigation the influence of the fiber son the evolution of mechanical properties of the concrete affected by high temperature by destructive and non-destructive test method

This paper presents an experimental examination of the effect of high temperatures on concrete prepared with different fibers types. For this study the concrete were prepared with four types of fibers (Steel, polypropylene, carbon and the combination of several types of fibers) and water/cement ratio fixed (w/c of 0.35). Specimens were heated under five different temperatures: 20 °C (ambient temperature), of 200 ºC, 300, 400 ºC and 600 ºC respectively. The following settings: compressive strength, ultrasonic pulse velocity, rebound hammer, concrete mass loss, and water porosity were examined in this Research experimental. Also A scanning electron microscopy study was used to comprehend the change in texture. The cracks were also examined using a microscope and other methods. This article is a contribution to the general understanding of the impact of fibers in high temperature concrete and highlights the significant impact of different types of fibers on the physical and mechanical properties of concrete who they were explore using destructive and nondestructive methods.

Comprehensive Characterization of Surface-Bound Proteins and Measurement of Fibrin Fiber Thickness on Extracorporeal Membrane Oxygenation Circuits Collected From Patients.

To characterize surface-bound proteins and to measure the thickness of fibrin fibers bound to extracorporeal membrane oxygenation (ECMO) circuits used in children. Single-center observational prospective study, April to November 2021. PICU, Royal Children's Hospital, Melbourne, Australia. Patients aged less than 18 years on venoarterial ECMO and without preexisting disorder. None. ECMO circuits were collected from six patients. Circuit samples were collected from five different sites, and subsequently processed for proteomic and scanning electron microscopy (SEM) studies. The concentration of proteins bound to ECMO circuit samples was measured using a bicinchoninic acid protein assay, whereas characterization of the bound proteome was performed using data-independent acquisition mass spectrometry. The Reactome Over-representation Pathway Analyses tool was used to identify functional pathways related to bound proteins. For the SEM studies, ECMO circuit samples were prepared and imaged, and the thickness of bound fibrin fibers was measured using the Fiji ImageJ software, version 1.53c (https://imagej.net/software/fiji/). Protein binding to ECMO circuit samples and fibrin networks showed significant intra-circuit and interpatient variation. The median (range) total protein concentration was 19.0 (0-76.9) μg/mL, and the median total number of proteins was 2011 (1435-2777). A total of 933 proteins were commonly bound to ECMO circuit samples from all patients and were functionally involved in 212 pathways, with signal transduction, cell cycle, and metabolism of proteins being the top three pathway categories. The median intra-circuit fibrin fiber thickness was 0.20 (0.15-0.24) μm, whereas the median interpatient fibrin fiber thickness was 0.18 (0.15-0.21) μm. In this report, we have characterized proteins and fiber fibrin thickness bound to ECMO circuits in six children. The techniques and approaches may be useful for investigating interactions between blood, coagulation, and the ECMO circuit and have the potential for circuit design.

Thermal Treatment Effects on Structure and Mechanical Properties of Polybutylene Terephthalate and Epoxy Resin Composites Reinforced with Glass Fiber.

In this study, two types of composites, polybutylene terephthalate (PBT) and epoxy resin (ER), reinforced with 20% of glass fiber (GF) are used as the comparative research objects. Their mechanical properties after thermal aging at 85~145 °C are evaluated by tensile strength and fracture morphology analysis. The results show that the composites have similar aging laws. The tensile strength of GF/PBT and GF/ER decrease gradually with the increase of aging temperature, while their elastic moduli are independent of the thermal treatment temperature. Scanning electron microscopy study of the fracture surface shows that separation of glass fiber from PBT and ER matrix becomes more obvious at higher aging temperature. The fibers on the matrix surface appear clear and smooth, and the whole pulled out GFs can be observed. As a main mechanical strength degradation mechanism, the deterioration of interface adhesion between the matrix and GF is discussed. A large difference in coefficients of thermal expansion of the matrix and GF is a main factor of the mechanical degradation.

Development of Nickel-Chromium Alloy Electroplating and Its Surface Morphology Studies for Automobile Industries

In the electroplating industry, alloy plating is typically one of the most difficult processes. We are showcasing the Ni-Cr (Nickel Chromium) alloy electroplating in our work. Trivalent chromium bath is made in order to resist the hazardous hexavalent chromium, and co-deposition of chromium and nickel is accomplished. Our work is appropriate for industrial electroplating in the automotive industry because Ni-Cr alloy exhibits good corrosion resistance along with features including wear resistance, ductility, and thermal stability. Through the use of SEM (Scanning Electron Microscopy), EDAX (Energy Dispersive X-Ray Analysis), and XRD (X-Ray Diffraction) studies, we are able to clearly observe the surface morphology in this project. These research allow us to observe the Porous behavior surfaces. Figure 1

Sustained-Release Microspheres of Cyclodextrin-Resveratrol Complex Using Fenugreek Galactomannan Hydrogels: A Green Approach to Phytonutrient Delivery.

Food matrices are becoming increasingly complex with the impregnation of phytonutrients with health-beneficial pharmacological effects. Herein, we report the preparation, characterization, and functional application of soluble and stable microspheres of trans-resveratrol (t-RES) developed through a water-based green process involving cyclodextrin (CD) and fenugreek galactomannan (FG). Spectroscopic and thermodynamic calculations identified γ-CD as the best CD to form a stable cyclodextrin-resveratrol inclusion complex (CD-R, 49-fold enhanced solubility); however, it exhibited a burst release profile. The sustained release of resveratrol was achieved by further encapsulating the inclusion complex within the fenugreek galactomannan hydrogel scaffold by a gel-phase dispersion process, resulting in an amorphous powder (FG-CD-R) as evident from powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) studies. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) studies confirmed the formation of the inclusion complex with no chemical alterations. When dissolved in water, FG-CD-R swelled and released stable cuboid structures with an average particle size of 500 ± 53 nm with a zeta potential of -52 ± 5.3 mV. FG-CD-R demonstrated a sustained-release profile upon in vitro release studies. Accelerated study demonstrated its stability for a shelf-life of two years. Further it was shown to be suitable for the preparation of transparent gummies with improved sensory attributes compared to unformulated t-RES. In summary, FG-CD-R is simple to prepare and easily scalable, providing a sustained-release t-RES with a natural, food-grade, and clean label status (non-genetically modified, allergen-free, vegan, and free from residual solvents) for nutritional applications.

Effect of reinforcement particle size on the corrosion and mechanical properties of spark plasma sintered aluminium matrix composites.

In this study, the effects of different sizes of reinforcing particles on the corrosion behaviour and mechanical properties of aluminium (Al)-based composites produced by spark plasma sintering (SPS) are analysed. In the study, the effects of SPS parameters, including electrical power, applied pressure and sintering temperature, on the consolidation process and microstructure evolution of the composite are closely investigated. The results reveal a nuanced relationship between the sintering conditions and the properties of the particles, which in turn determine the sintering dynamics and the formation of the microstructural features. The evaluation of mechanical properties indicates a remarkable influence of particle size distribution on the hardness of the composites, showing an initial improvement with the introduction of nanoparticles, followed by a slight decrease as the balance between nano- and micron-sized Al2O3 particles shifts. A scanning electron microscopy (SEM) study demonstrates the influence of particle dimensions on the change of grain boundaries and the spatial arrangement of the composite matrix. Electrochemical experiments in a 0.1M NaCl solution show a consistent corrosion potential (Ecorr) across all samples, while the current densities associated with corrosion (icorr) show considerable variation. The presence of nano-sized Al2O3 particles was found to increase corrosion resistance, in contrast to the detrimental effects observed with larger microparticles. In particular, composites with a bimodal distribution of particle sizes showed a 3.5-fold increase in corrosion resistance compared to pure Al. The specific Al-2n8mAl2O3 composite that exhibited active electrochemical properties at elevated potentials without a defined passivation range emphasises the significant role of particle size. This study draws attention to bimodal microstructures as a promising route to achieving uniformity and improved corrosion resistance in Al matrix composites, while pointing to the need for further research to fully elucidate the operative mechanisms.

Study of temperature-dependent copper iodide thin film by thermal evaporation system

The development of heterostructure devices has gained significant attention towards scientific communities in the present time. This article reports on the effective use of the horizontal thermal evaporation (TE) method to successfully fabricate copper iodide (CuI) films on silicon (Si) substrates. By using the TE technique, CuI-based heterojunctions have been fabricated in this research . CuI exhibits semiconductor qualities of the p-type, making it a promising option for optoelectronic devices in the future. The temperature was varied from room temperature (RT) to 230 °C to synthesise the CuI/Si heterojunction. The structural, morphological, optical, and electrical analyses have been carried out with various substrate temperatures. The x-ray diffraction (XRD) data shows that the CuI films have demonstrated a polycrystalline character and have lattice parameters of 6.03 Å. The Raman spectroscopy study shows the microstructural analysis of CuI films. The field emission scanning electron microscopy (FESEM) study reveals the variation of grain size and shape with synthesis temperature. The atomic force microscope (AFM) was used to estimate the surface roughness. The CuI films were found to be p-type by the Hall effect measurement. The sample synthesised at 130 °C shows the highest mobility of 83.12 cm2 V−1 s−1 with a carrier concentration of 1019 cm−3. The UV-visible (UV–vis) spectroscopy measurements show good absorption of UV light by the CuI thin films. The CuI/Si heterojunctions are rectifying, as demonstrated by the I-V measurements, and those respond well to UV light irradiation.

Slurry infiltrated low-quality construction and demolition coarse aggregate waste in concrete – a sustainable construction

Exponential growth in infrastructure projects, stimulated by emerging sophisticated technologies have been instrumental in the salutary proliferation of the construction sector, globally. An indubitable adversity of the rapid boom in the construction industry has been the rampant cumulative fallout of burgeoning waste during the demolition and construction phases of restoration. The current study explored the propriety of replacing natural coarse aggregate by low-quality recycled coarse aggregates (RCA) with varying proportions, along with silica fume (SF) and polypropylene (PP) fibers as admixtures, for the preparation of concrete. As the quality of RCA is determined by the history of its parent demolished structure, this investigation was preceded by assessment of the properties of RCA. A statistical approach using design of experiments, adopted to determine the coherent combinations of RCA and admixtures, yielded 16 combinations. Accordingly, concrete specimens were prepared with various quantities of RCA in place of natural coarse aggregate. Optimum proportions of the ingredients were inferred, based on the compressive strength attained by the concrete specimens. Further strength property evaluation was conducted, using these low-quality RCA treated with cement and silica fume slurry. Based on the strength results, 75% slurry infiltrated RCA, coupled with 10% SF and 0.5% PP, provided better strength in compression, tension and flexure. Scanning electron microscopy study, adopted for characterization of the micro-structural slurry-infiltrated RCA, shows the presence of strong interfacial transition zone in the treated RCA concrete. Thus, this study confirmed the efficacy of low-quality RCA as a promising material for structural construction, concurrent with a solution to various ecological disruptions precipitated by infrastructure construction and demolition wastes.

An SEM study on the effect of 9.3-µm CO2 laser on dentinal tubules for hypersensitivity treatment.

In-vitro studies were performed on dentin of extracted human molars to investigate the effectiveness of 9.3μm CO2 laser irradiation to occlude dentinal tubules. The observed occlusion of dentinal tubules with the irradiation was compared with application of three reagents: 2% Sodium Fluoride gel, an aqueous solution of hydroxyapatite nanoparticles and an equal mix of the two. We show that 9.3μm CO2 laser irradiation occludes dentinal tubules, and the use of laser irradiation produces better occlusion of the opened tubules compared to the use of topical reagents. Nine extracted and cleaned human molars were cut to obtain dentin disks of thickness of 3-5mm. Each disc was divided into four quarters, and each quarter served as two samples corresponding to irradiated and non-irradiated group counterparts. Five disks were used to study the effect of various laser irradiation energies on the dentinal tubules to find a good pulse fluence for occlusion of the dentinal tubules, and four disks were used for studying the effects of reagents and irradiation at the pulse fluences found in the first part of the study. The samples were irradiated with a beam diameter of 1mm (1/e2) at 15Hz pulse repetition rate, scanned automatically using a set of scanning mirrors. Samples were imaged using Scanning Electron Microscope (SEM) which were processed to determine tubule diameter. Safety of the irradiation treatment was investigated on 6 samples by measuring pulpal temperature rise. The effect of three topical reagents corresponding to 2% Sodium Fluoride gel (F), Hydroxyapatite nanoparticles (HA) and an equal mix of F and HA (HAF) on dentinal tubule occlusion was evaluated and compared with the laser irradiation. In all examined cases, laser irradiation at a fluence of 0.81J/cm2 resulted in a temperature increase less than 3°C which is safe, and no surface cracking was observed. There is a threshold pulse fluence of 0.27J/cm2 above which, laser produced surface melting. At a pulse fluence of 0.81J/cm2 a layer of recast of melted dentin was formed. Under this layer, peritubular dentin melting and occluding of the dentinal tubules was observed. Application of either F or HA or HAF did not produce visible occlusion effect on open tubules after washing and microbrushing with excess distilled water. 9.3μm CO2 laser irradiation on extracted human molar dentin at pulse fluence of 0.81J./cm2 resulted in tubule area reduction by 97% without rising pulpal temperatures to unsafe levels.