Phosphate Peak Research Articles

Raman Spectroscopic Analysis of Urinary Creatine and Phosphate in Athletes: Pre- and Post-Training Assessment.

The aim of this study was to detect biochemical components in the urine of bodybuilders who ingested creatine pretraining compared to individuals who did not ingest creatine after physical exercise using Raman spectroscopy. Twenty volunteers practicing bodybuilding were selected to collect pre- and post-training urine samples, where 10 volunteers ingested creatine 30 min before pretraining urine collection (creatine group), and 10 did not (control group). The samples were subjected to Raman spectroscopy, and the spectra of both creatine and control groups and the difference (post-pre) for both groups were analyzed. Principal component analysis (PCA) technique was applied to the samples. The results showed peaks of creatine and phosphate in urine after training (creatine post-training group), suggesting that part of the creatine was absorbed and metabolized, and part was excreted. Raman spectroscopy could be applied to detect biocompounds in urine, such as unmetabolized creatine and phosphate.

The role of artificial ponds for anuran diversity in managed areas of the Atlantic Forest

ABSTRACT Artificial ponds can be important reproductive sites for anurans in human-disturbed habitats. However, this capacity depends on the configuration of the habitat where they are inserted. We evaluated how anuran beta diversity was influenced by the configuration of the surrounding habitat and water parameters in artificial ponds in southern Brazil. Physicochemical parameters of water and the configuration of the surrounding habitat were the elements that best explained the variation in beta diversity. However, the surrounding habitat had a predominant role in the differences between communities. The level of exposed soil was the component that best acted on the turnover component of beta diversity followed by urbanization, which highlights the impact of human presence on anuran diversity. In other words, we observed that anthropogenic changes caused changes in species composition in the evaluated ponds. Among water parameters, only phosphate was relevant for the configuration of communities. Phosphate peaks may result from sewage or fertilizer contamination, not infrequent in the region despite the low human density and the small-scale agriculture economy. Even though they are anthropogenic environments, artificial ponds can help maintain the anuran communities, but their effectiveness will depend on the presence of forest remnants and water quality.

Discrimination of ivory from extant and extinct elephant species using Raman spectroscopy: A potential non-destructive technique for combating illegal wildlife trade.

The use of elephant ivory as a commodity is a factor in declining elephant populations. Despite recent worldwide elephant ivory trade bans, mammoth ivory trade remains unregulated. This complicates law enforcement efforts, as distinguishing between ivory from extant and extinct species requires costly, destructive and time consuming methods. Elephant and mammoth ivory mainly consists of dentine, a mineralized connective tissue that contains an organic collagenous component and an inorganic component of calcium phosphate minerals, similar in structure to hydroxyapatite crystals. Raman spectroscopy is a non-invasive laser-based technique that has previously been used for the study of bone and mineral chemistry. Ivory and bone have similar biochemical properties, making Raman spectroscopy a promising method for species identification based on ivory. This study aimed to test the hypothesis that it is possible to identify differences in the chemistry of mammoth and elephant ivory using Raman spectroscopy. Mammoth and elephant tusks were obtained from the Natural History Museum in London, UK. Included in this study were eight samples of ivory from Mammuthus primigenius, two samples of carved ivory bangles from Africa (Loxodonta species), and one cross section of a tusk from Elephas maximus. The ivory was scanned using an inVia Raman micro spectrometer equipped with a x50 objective lens and a 785nm laser. Spectra were acquired using line maps and individual spectral points were acquired randomly or at points of interest on all samples. The data was then analysed using principal component analysis (PCA) with use of an in-house MATLAB script. Univariate analysis of peak intensity ratios of phosphate to amide I and III peaks, and carbonate to phosphate peaks showed statistical differences (p<0.0001) in the average peak intensity ratios between Mammuthus primigenius, Loxodonta spp. and Elephas maximus. Full width at half maximum hight (FWHM)analysis of the phosphate peak demonstrated higher crystal maturity of Mammuthus primigenius compared to living elephant species. The results of the study have established that spectra acquired by Raman spectroscopy can be separated into distinct classes through PCA. In conclusion, this study has shown that well-preserved mammoth and elephant ivory has the potential to be characterized using Raman spectroscopy, providing a promising method for species identification. The results of this study will be valuable in developing quick and non-destructive methods for the identification of ivory, which will have direct applications in archaeology and the regulation of international trade.

Analyzing the Characteristics of Fishbone Powder Derived from Pangasius sp., Thunnus tonggol, and Thunnus albacares as Food Fortificant

Pangasius sp., Thunnus tonggol (T. tonggol), and Thunnus albacares (T. albacares) are high-value commercial species widely used in fillet production, generating by-products, such as fishbone. The fishbone, rich in calcium (CA) and phosphorus (P), offers a valuable alternative for daily Ca intake. Using such by-products as a potential source of Ca presents a viable solution, offering food-fortificant ingredients applicable in various food products. Therefore, this study examined the physical and chemical properties of fishbone powder derived from Pangasius sp., T. tonggol, and T. albacares. The products preparations were subjected to cooking, autoclaving, pulverization, homogenization, drying, and grinding. The physical and chemical analysis of fishbone powder showed that T. tonggol and T. albacares had a darker color compared to Pangasius sp., with higher protein content and likely stimulation of a Maillard reaction during the drying process. All species maintained a neutral pH range, and their particle sizes significantly differed (p&lt; 0.05), ranging from nm to µm. SEM images showed irregularly shaped and agglomerated particles in all fish species. The ash content was 54.35 g/100 g (Pangasius sp.), 53.62 g/100 g (T. tonggol), and 52.28 g/100 g (T. albacares), showing high mineral content, particularly in Ca exceeding 40%. The analysis of a Fourier transform infrared spectroscopy (FT-IR) showed carbonate and phosphate peaks, representing the presence of calcium salts. Based on the evaluation, fishbone powder for each species had the potential to serve as food fortificant.

Assessing the usefulness of Raman spectroscopy and lipid analysis of decomposed human bones in forensic genetics and molecular taphonomy

Bones are among the structures most likely to be recovered after death. However, the low quantity of preserved DNA and complex processing from sample to DNA profile make forensic DNA analysis of bones a challenging task. Raman spectroscopy and gas chromatography-mass spectrometry (GC/MS), have the potential to be useful as screening tools for DNA analysis and in decomposition studies. The objective of this research was to assess the usefulness of such molecular investigations. Femur samples collected from 50 decomposing human bodies were subjected to Raman spectroscopy and GC/MS. Assessment of nuclear DNA quantity and short tandem repeat (STR) genotyping efficiency were also performed. Raman parameters (crystallinity, carbonate-to-phosphate ratio, mineral-to-matrix ratio) and detected lipids were recorded. Background fluorescence proved problematic for Raman analysis of forensic bones. Regardless, it was not associated with less preserved DNA or less detected STR alleles. Fatty acids, hydrocarbons, and five types of fatty acid methyl esters (FAMEs) were detected. The main phosphate peak position in Raman spectra was significantly correlated with preserved DNA (p = 0.03713), while significantly more STR alleles were detected in bones containing methyl hexadecenoate (p = 0.04236). Detection of FAMEs in the bone matrix suggests a reaction between methanol produced by bacteria and free fatty acids, which are not associated with the level of preservation of endogenous DNA. The techniques assessed have shown to be useful in molecular taphonomy studies and forensic genetics.

Measurement of sweat lactate levels in exercise and non-exercise activities using capillary electrophoresis system with contactless conductivity detection and cyclodextrin-modified buffer

This study presents the analysis of lactate in sweat using capillary electrophoresis with contactless conductivity detection. Two cyclodextrin (CD) compounds, carboxymethyl-β-cyclodextrin sodium salt (CM-β-CD) and heptakis (2,3,6-tri-O-benzoyl)-β-cyclodextrin (TRIME-β-CD), were evaluated as buffer modifiers for the separation of chloride, nitrate, sulfate, oxalate, maleate, acetate, lactate, and phosphate anions. The concentrations of these modifiers were tested at 0.05, 0.1, and 0.5 mM for eight anions separation. The buffer was 40.0 mM MES/L-His (pH 6.0) with 0.05 mM CTAB, resulting in anodic separation. Due to separation efficiency in resolving lactate and phosphate peaks, TRIME-β-CD at a concentration of 0.1 mM was selected as the suitable buffer additive for sweat lactate analysis. The calibration of the developed method, using maleate as an internal standard, resulted in the linear ranges of 0.1–5.0 mM, r2 of 0.9999, and an instrumental LOD of 0.042 mM. The intra-day and inter-day precisions of the relative migration time (RMT) were 0.3–0.4% and 3–4% RSD, respectively. Lactate levels in sweat samples from the same group of volunteers were measured after two distinct activities: exercise (after running) and non-exercise (after sauna). For non-exercise activities, lactate concentrations ranged from 15 ± 1 mM to 36 ± 2 mM. While, after exercise, the concentrations were between 26 ± 1 mM and 136 ± 1 mM. Further evaluation of the stability of sweat storage for monitoring lactate contents, it was found that the changes in lactate levels were insignificant when stored for up to 24 weeks at 4 °C. This was confirmed by paired t-tests (t-stat ragnes from -0.59 to 2.49; t-critical = 2.57, P = 0.05). The measured lactate concentrations from volunteers were significantly higher, approximately 2–6 times, in exercise activities compared to non-exercise activities. This substantial difference in lactate secretion indicates a clear distinction in the factors that stimulate sweat lactate production. To evaluate the intensity of exercise based on lactate levels in sweat, a proposed cut-off level of 36.0 mM, with a decision limit of 40.0 mM, can be proposed.

Color Adsorption Performance of Bone Biocomponent for Textile Dyeing Effluent Treatment in Ethiopia

The continued expansion of industrial growth has contributed significantly to the economic development of many countries. However, untreated discharge from the textile factory significant impacts freshwater and public health. The aim of this study is to explore the economical-local wastewater treatment for local textile industries. The experiment used the waste bones as a source of calcium-phosphate nanopowder (CNP) biocomponent, adsorbent for azo dye effluent treatment. An isolated biocomponent was analyzed using FTIR and UV-VIS, and its adsorption isotherm was also calculated. The FTIR analysis of CNP showed carbonates, amide, and high-intensity phosphate peaks of 1008 cm−1 and 1337 cm−1. The effect of contact time analyzed by UV-VIS absorption spectra revealed that 70% of color removal was achieved within 30 minutes and 60 minutes for disperse red 1 dye (DR1D) and DCT reactive blue 109 dyes (RB109D), respectively. In addition, the effects of the condition parameters on percentage color removal were analyzed using DOE response surface methodology. The maximum color removal performances are 98.65% and 96%, respectively, for DR1D and RB109D at neutral pH. The Langmuir isotherm was observed in the adsorption of RB109D effluent with an R2 value of 0.994 and the Freundlich isotherm in the adsorption of DR1D with an R2 value of 0.993. Finally, the gauge of the effectiveness of treatment was analyzed by COD, BOD, and TSS values before and after treatment. The maximum deduction percentages of COD, BOD, and TSS were 82, 87, and 70% from RB109D; 89, 90, and 89% from DR1D; and 82, 89, and 71% from the industry sample, respectively. Generally, the study showed that the current adsorbent was a good substitute for synthetic adsorbents.

Evaluation of near-infrared Raman spectroscopy in the differentiation of cortical bone, trabecular bone, and Bio-Oss bone graft: an ex-vivo study

We evaluated the ability of near-infrared Raman spectroscopy (near-IR RS) to differentiate among cortical bone, trabecular bone, and Bio-Oss, a bovinebone-based graft material. We obtained a thinly sliced section of the mandible to collect cortical and trabecular bone samples and placed compacted Bio-Oss bone graft into a partially edentulous mandible in a dry human skull to obtain a comparable Bio-Oss sample. We performed near-IR RS of the 3 samples and evaluated the resultant Raman spectra to evaluate their differences. We identified 3 sets of spectroscopic markers that differentiated Bio-Oss from human bone. The first consisted of significant shifts in the location of the 960 cm-1 phosphate (PO43-) peak and a reduction in its width, suggesting that Bio-Oss is more crystalline than bone. The second was the reduced carbonate content of Bio-Oss compared to bone, as determined from the 1070 cm-1/960 cm-1 peak area ratio. The final marker was the lack of collagen-associated peaks in Bio-Oss compared to cortical and trabecular bone. Near-IR RS can reliably differentiate human cortical and trabecular bone from Bio-Oss via 3 sets of spectral markers associated with mineral crystallinity, carbonate content, and collagen content that differ significantly between them. Integrating this modality into dental practice may assist in implant treatment planning.

Biochemical and Mechanical Analysis of Occlusal and Proximal Carious Lesions.

A precise evaluation of caries excavation endpoint is essential in clinical and laboratory investigations. Caries invasion differentiates dentin into structurally altered layers. This study assessed these changes using Raman spectroscopy and Vickers microhardness. Ten permanent molars with occlusal and proximal carious lesions were assessed and compared at 130 points utilizing four Raman spectroscopic peaks: phosphate v1 at 960 cm-1, amide I (1650 cm-1), amide III (1235 cm-1) and the C-H bond of the pyrrolidine ring (1450 cm-1). The phosphate-to-amide I peak ratio and collagen integrity peak ratio (amide III: C-H bond) of carious zones were calculated and compared in both lesions. The former ratio was correlated to 130 Vickers microhardness indentations through lesions. The caries-infected dentin (CID) exhibited low phosphate peak, but higher amide I, III and C-H bond peaks than other zones in both lesions. The peaks in amide regions (I and III) varied in occlusal versus proximal lesions. A high correlation was found between mineral: matrix peak ratio and equivalent microhardness number within carious lesions, while the collagen integrity peak ratio was applied in proximal lesions only. Raman spectroscopy detected changes in the mineral and matrix contents within different carious zones and regions.

Effect of chitosan irrigant solutions on the release of bioactive proteins from root dentin.

To identify the effect of two chitosan solutions on the release of root dentin matrix proteins and to describe the chemical changes observed following conditioning with chelating agents. The release of dentin sialoprotein (DSP), transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor (VEGF), and platelet-derived growth factor-BB (PDGF-BB) with different chelating agents, including ethylenediaminetetraacetic acid (EDTA), chitosan solution (CS), and nanoparticulate chitosan (CSnp), was investigated. DSP was quantified using an enzyme-linked immunosorbent assay (ELISA). TGF-β1, VEGF, and PDGF-BB were quantified using a cytokine bead panel (CBA). Raman spectroscopy was performed to identify surface chemical changes. Statistical analysis was performed using Kruskal-Wallis test with Mann-Whitney-Wilcoxon rank-sum test (p < 0.05). TGF-β1, VEGF, and DSP solubilized in all irrigants tested. CSnp showed the highest concentration of DSP. PDGF-BB did not exceed the detection limits. Raman spectroscopy revealed a decrease in the phosphate and carbonate peaks, representing the chelating effect of EDTA, CS, and CSnp. Additionally, CSnp showed the greatest preservation of the amide I and III content. Proteins can be released from dentin via EDTA, CS, and CSnp conditioning. Raman spectroscopic revealed changes in the inorganic content of the root dentin after chelation. Furthermore, use of CSnp facilitated a preservation of the organic content. Chelation allows the release of proteins, justifying the use of chelating agents in regenerative endodontics. The chitosan-dentin matrix interaction also promotes the protection of the organic content as an additional benefit to its protein releasing effect.

Evaluation of Effects of Various Irrigating Solutions on Chemical Structure of Root Canal Dentin Using FTIR, SEM, and EDS: An In Vitro Study.

Background: Sequential chemical application for irrigating a root canal during chemomechanical debridement can affect the dentin microstructure. Understanding the effects of various irrigants on chemical properties of dentin can elucidate their effects on physical properties and thereby explain the higher incidence of structural failure in endodontically treated teeth. This in vitro research aimed to compare and evaluate the effects of three different irrigating solutions on the chemical structure of root canal dentin in extracted human teeth. Methods: Forty-eight extracted single-rooted mandibular premolar teeth were sectioned at the cemento–enamel junction by a diamond disc and were then randomly assigned to four groups of twelve samples each. The groups were irrigated using 5.25% NaOCl, ozonated olive oil, silver citrate, or distilled water. Dentin sections measuring 1.5 mm were obtained from the root portion and each section and were analyzed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and electron-dispersive spectroscopy (EDS). FTIR and EDS values are reported as means ± standard deviations. Data were analyzed using an ANOVA and a post hoc Bonferroni test (p < 0.05). Results: A comparison of the FTIR and EDS values among the groups using ANOVA revealed statistically significant differences in the organic and inorganic peak values among the groups. An intergroup comparison between NaOCl with silver citrate and ozonated olive oil revealed significant reductions in the carbonate and phosphate peak values in the NaOCl group (p < 0.05). The EDS values tabulated for the carbon, oxygen, phosphorous, and calcium peak levels showed significant differences between the groups using an ANOVA. An SEM analysis was conducted under 1500× magnification, which revealed smear layer removal in the silver citrate group. Conclusions: The silver citrate solution and the ozonated olive oil caused less changes in the organic and mineral contents of dentin than sodium hypochlorite.

Evaluation of the mineral-promoting effects of in-office bleaching on experimental subsurface enamel lesions

The aim of this study was to investigate the mineral-promoting effects of in-office bleaching agent on enamel subsurface lesions. Enamel subsurface lesions were divided into following groups; D: demineralized samples without any further treatment, DS: samples were further immersed in fresh saliva, DSR: samples were immersed in saliva followed by remineralization buffer, and DSBR: samples were immersed in saliva, subjected to in-office bleaching, and then immersed in remineralization buffer. The control group (CONT) consisted of untreated enamel specimens. Transverse microradiography showed that integrated mineral loss was significantly lower in the DSBR group than in the DSR group. Confocal laser Raman analysis revealed that ν1 phosphate peak height of 959 cm-1 and mineral to matrix ratio of peak heights 959 cm-1 to 1,610 cm-1 in the DSBR group were similar to those in the CONT. In-office bleaching can promote enamel remineralization by altering or removing proteins infiltrated to enamel subsurface lesions.

Potential role of Er:YAG laser and fluoride in the dental enamel remineralization: a Raman spectroscopy preliminary &lt;i&gt;ex vivo&lt;/i&gt; study

Background and aims: Dental caries are a widespread oral disease and a serious public health problem, starting by teeth demineralization, which is a loss of minerals such as calcium and phosphate. Modern caries treatment is aimed at preventing the disease progression by teeth remineralization which is a supply of minerals to the enamel. The most popular remineralization method is the treatment of teeth with fluoride. Er:YAG laser has also gained research attention as a method for improving the uptake of fluoride and phosphate by introducing chemical and morphological changes into the structure of enamel but, while some researchers described it as effective, others found no significant effect from its application. This work aimed to further study the effect of Er:YAG laser, alone or combined with fluoride, to dental enamel. Materials and Methods: Twenty upper central human incisors, extracted for periodontal reasons, were used in the study. Samples were demineralized by acetic acid and divided into four groups: a) control, b) fluoride + Er:YAG laser, c) Er:YAG laser alone and d) fluoride alone. The remineralization rate of teeth was estimated by Raman Spectroscopy. Results: In comparison with the control group, the phosphate peak’s intensity increased notably for the teeth treated by fluoride, but decreased slightly for the teeth treated with Er:YAG laser and with a combination of the laser and fluoride. Conclusions: With the limits of this study, due to the limited samples number, Er:YAG laser, alone and combined with fluoride, seems to be not effective, at the parameters used, for the enamel remineralization.

Effect of Different Concentrations of Silver Nanoparticles on the Quality of the Chemical Bond of Glass Ionomer Cement Dentine in Primary Teeth

Background: The nanotechnologies have been applied for dental restorative materials manufacturing such as glass ionomer cement, composites, tooth regeneration, and endodontic sealers. The study aimed to investigate the chemical bond of conventional glass ionomer cement and to evaluate the addition of different concentrations of silver nanoparticles (AgNPs) on the quality of the chemical bond of glass ionomer cement to primary dentin. Methods: Silver nanoparticle (AgNP) powder was added in concentrations of 0.2, 0.4, and 0.6% to the conventional powder of GIC Fuji II. Then, the powder was added to the liquid and mixed with the recommended powder/liquid ratio of 3.6:1 g. The Fourier-transform infrared spectra (FTIR) of teeth with 0.2%, 0.4%, and 0.6% w/w of silver nanoparticles in GIC fills and the control tooth were obtained. The conventional glass ionomer was used as a control group. The control and the plain silver tooth were subjected to FTIR analysis using an ATR–FTIR spectrophotometer (ThermoFisher Scientific, Waltham, MA, United States) with zinc selenide (ZnSe) ATR crystal (attenuated total reflection) and OPUS v7.5 software. All spectra were recorded in the range of 500–3,500 cm−1 in the transmission mode with an ATR module. Results: The AgNPs added at 0.2, 0.4, and 0.6% concentration to GIC provided some information in the context of bond interaction with the dentin. Various bond peaks were seen for calcium, carbonate, phosphate, and amide. In our study, only the amide and phosphate were generated. The amide peaks were almost similar to the control, 0.2%, 0.4%, and 0.6%, with the peaks in the range of 1250–1650 cm−1. There was a clear shift in the phosphate peak from the control, 0.2, and 0.4%, which was about 1050 cm−1, whereas for 0.6%, there was a clear shift from 1050 cm−1 to 880 cm−1. Conclusion: GIC supplemented with AgNPs showed that a concentration above 0.4% of AgNPs altered the bond quality in dentin interaction. In conclusion, adding AgNPs at a minimal level improves the mechanical properties and maintains the same bond quality as GIC.

Hepatocellular liver injury in hospitalized patients affected by COVID-19: Presence of different risk factors at different time points.

BackgroundPrevalence and clinical impact of increased liver function tests in patients affected by Coronavirus disease 2019 (COVID-19) is controversial.AimsThis observational study evaluates the prevalence of transaminases elevation in hospitalized patients affected by COVID-19 and investigates the presence of factors associated with hepatocellular injury and with mortality.MethodsData of 292 adult patients with confirmed COVID-19 admitted to the Ente Ospedaliero Cantonale (Switzerland) were retrospectively analyzed.ResultsTransaminases were increased in about one-third of patients on hospital admission and two-thirds of patients during the hospital stay. On hospital admission, transaminases were more commonly elevated in younger patients, who also reported elevated C reactive protein and a higher degree of respiratory failure. Independent factors associated with abnormal transaminases during hospitalization were drugs, in particular paracetamol (OR=2.67; 95% CI=1.38–5.18; p = 0.004) and remdesivir (OR=5.16; 95% CI=1.10–24.26; p = 0.04). Mortality was independently associated to age (OR = 1.09; 95% CI=1.05–1.13; p<0.001), admission to intensive care unit (OR=5.22; 95% CI=2.28–11.90; p<0.001) and alkaline phosphatase peak (OR=1.01; 95% CI=1.00- 1.01; p = 0.01).ConclusionsOn hospital admission, factors associated with liver damage were linked to demographic and clinical characteristics (age, inflammation and hypoxia) while, during hospitalization, drug treatment was related to development and progression of hepatocellular damage. Mortality was associated with alkaline phosphate peak value.

A Validated Method for Separation and Determination of Codeine Phosphate Hemihydrate Impurities in Bilayer Tablet Dosage Form of Naproxen Sodium and Codeine Phosphate by Using UHPLC

Background: Apranax Plus® is a new bilayer tablet dosage form, which combines two active pharmaceutical ingredients: naproxen sodium and codeine phosphate. Objective: The purpose of this work was to develop an ultra-high-performance liquid chromatography (UHPLC) method for the separation and determination of codeine phosphate hemihydrate impurities in a bilayer tablet dosage form. Methods: The separation and determination of codeine phosphate hemihydrate and its impurities, methylcodeine, morphine, codeine dimer, 10-hydroxycodeine, 14-hydroxycodeine, thebaine and codeinone were achieved by using reversed-phase liquid chromatography with TUV (Tunable UV Detector) and PDA (Photodiode Array Detector) detection by UHPLC. The new proposed method utilized by the Waters Acquity UHPLC® TUV and PDA systems using a UHPLC column Waters Acquity, BEH, C18, 2.1x100 mm, 1.7 μm particle size with a mixture of component A and acetonitrile in a gradient mode at a flow rate of 0.3mL/min, at 25°C with a load of 5μL. The detection for all eluted compounds was carried out at 245nm. Results: The codeine phosphate hemihydrate and peaks of its impurities were adequately obtained, thus proving the stability-indicating power of the method. The developed method was validated as per the ICH guidelines with respect to parameters such as precision, accuracy, linearity, limit of detection (LOD), limit of quantification (LOQ) and robustness. Conclusion: It was verified as being adequate for all the mentioned impurities of codeine phosphate hemihydrate. The described method was found to be useful for routine purity testing and was also found suitable for the analysis of the stability samples of the drug product.

Influence of ER-CR-YSGG Laser and Photodynamic Therapy on the Dentin Bond Integrity of Nano-Hydroxyapatite Containing Resin Dentin Adhesive: SEM-EDX, Micro-Raman, Micro-Tensile, and FTIR Evaluation.

The study aimed to analyze the effect of the addition of nano-hydroxyapatite (nano-HA) particles on the mechanical properties of experimental adhesive (EA). Furthermore, dentin interaction of EA (without nano-HA) and EA with nano-HA (hereon referred to as HA-10%) were also investigated and equated. Methods consisting of scanning electron microscopy (SEM)–energy-dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy, micro-tensile bond strength (µTBS) test, and Fourier transform infrared (FTIR) spectroscopy were employed to study nano-HA particles shape, dentin bond strength, degree of conversion (DC), and adhesive–dentin interaction. Ninety teeth (N = 90) were collected, and pre-bonding, conditioning of dentin was performed utilizing phosphoric acid (H3PO4) etching, photodynamic therapy (PDT), and ER-CR-YSGG (ECY) laser. The teeth were set to form bonded specimens using two adhesives. Nano-HA particles were spherical-shaped, and EDX confirmed the presence of oxygen, calcium, and phosphorus. Micro-Raman spectroscopy revealed distinct phosphate and carbonate peaks for nano-HA. The µTBS test demonstrated highest values for HA-10% group on the H3PO4 conditioned dentin. The greatest DC was observed for the EA group. The addition of nano-HA-10 wt.% particles in dentin adhesive resulted in improved bond strength. The incorporation also demonstrated acceptable DC (although lower than EA group), suitable dentin interaction, and resin tag formation.

Chemical and morphological changes of femtosecond laser-irradiated enamel using subablative parameters.

Chemical composition of dental enamel has a great relationship with the prevention of caries. The objective of the present work was to evaluate the chemical and morphological changes of femtosecond laser-irradiated enamel with subablative parameters using Raman spectroscopy, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM). Bovine incisor teeth were used to obtain 30 enamel specimens (5 × 5 mm2 ). The chemical composition of the control sample was analyzed by Raman spectrometry to acquire the absorption spectrum, delimiting the areas under the carbonate and phosphate bands. This analysis was used to evaluate the change in the chemical composition of the sample after irradiation. The specimens were irradiated (IRR) with a Ti:Sapphire laser system (pulsed and focused modes, femtosecond regime 70 fs, average power of 1W and exposure time of 15 s). After irradiation, the areas under the carbonate and phosphate absorption bands were delimited in each specimen. Raman spectrometry data were analyzed using Student's t-test (α=5%). By comparing the spectra of the IRR and non-irradiated (NI) specimens, the results showed a significant increase in the area value for the phosphate peaks and a significant reduction in the area value for the carbonate peak and the carbonate:phosphate ratio. CLSM and SEM analyses did not reveal structural alterations in the subsurface nor morphological alterations in the IRR enamel surface, respectively. It was concluded that femtosecond laser irradiation using subablative parameters reduced the carbonate content and the carbonate/phosphate ratio without altering the structure and morphology of the dental enamel.

Effect of Some Modifier Ions in CuO Doped Sodium Borosilicate Antibacterial Bioglass

A set of sodium borosilicate glasses mixed with different modifier oxides, viz., Li2O, MgO, CaO and ZnO, doped with antimicrobial oxide viz. CuO were synthesized. The structural (FT-IR spectroscopy, SEM and XRD) and bioactivity studies of the glasses were carried out before and after 30 days of immersion in simulated body fluid (SBF) under static conditions. Optical absorption spectra of all the glasses exhibited a broad absorption band identified due to 2B1g→2B2g octahedral transition of Cu2+ ions. Glass microstructure is analyzed using SEM images and XRD patterns to authenticate glass bioactivity (viz. to confirm whether there is formation of hydroxyapatite (HAp) layer on the surface). For further confirmation of the formation of HAp on the surface of the post immerse samples, the FTIR spectra were recorded. The spectra revealed some vibrational peaks of calcium phosphate. Solubility (weight loss due to immersion in SBF) percentage is found to be different for different modifiers mixed glasses containing antibacterial CuO. SEM results confirm apparent nodular calcium phosphate microcrystalites. It is observed that the addition of antimicrobial oxide has a positive effect on the bioactivity of glass and make these glasses as fourth-generation biomaterials, which are being extensively used to heal the wounds in the human body by facilitating the growth of soft tissues.

Phosphorus MR spectroscopy and 18F-FDG PET/CT in the study of energy metabolism of glial tumors

To study energy metabolism in glial tumors using dynamic MR spectroscopy and 18F-FDG PET/CT. The study included 19 patients (9 women and 10 men) with newly diagnosed supratentorial glial tumors WHO Grade I-IV (diffuse astrocytoma - 4 cases, oligodendroglioma - 4 cases, anaplastic astrocytoma - 5 cases, glioblastoma - 6 cases). All patients underwent examination and surgical treatment at the Burdenko Neurosurgery Center. Dynamic MR spectroscopy and 18F-FDG PET/CT were applied in each patient. We found multiple correlations between the ratio of bioorganic phosphate peaks and parameters of glucose uptake by tumor tissue. These relationships were more significant in patients with high-grade tumors: positive significant correlation between SUVtumor and PME/PCr ratio (RS=0.75, p=0.01), T/Nmix and βATP/Pi ratio (Rs=0.76, p=0.02), SUVpeaktumor and aATP/Pi ratio (RS=0.77, p=0.008). Moreover, there were negative correlations between SUVtumor and PCr/bATP ratio (RS= -0.66, p=0.05), T/Nmix and PDE/bATP ratio (RS= -0.83, p=0.006), SUVpeaktumor and PDE/aATP ratio (RS= -0.76, p=0.009). High-grade gliomas were characterized by higher glucose consumption, ATP release (intensification of energy metabolism) and faster cell membrane synthesis. These processes indicate enhanced proliferation of tumor cells (intensification of plastic metabolism).