جستجوی مقالات مرتبط با کلیدواژه « Spectroscopy » در نشریات گروه « پزشکی »

Backgraound: 

Polysaccharides, particularly Carboxymethyl Cellulose (CMC) and Ammoniacum Gum (AMG), are considered valuable due to their thermal stability and non-toxicity. CMC has good film-forming ability but weak mechanical properties, while AMG shows promise with its unique chemical composition. Additionally, essential oils, such as Clove Essential Oil (CEO), are being used to enhance the antimicrobial properties of edible films, offering a natural way to extend the shelf life of food products.

This study investigated the combined effect of CMC: 0.5-1.5 wt %, AMG: 1-5 wt %, as well as CEO: 0-30 v/v % on the physical characteristics of the CMC-AMG films by Response Surface Methodology. The optimization was performed with the aim of maximizing Whiteness Index, Ultimate Tensile Strength (UTS), and Strain at Break (SB) and minimizing total color difference (ΔE) values. Fourier-Transform Infrared Spectroscopy, film microstructure, Differential Scanning Calorimeter analysis, and antibacterial activity were investigated. The analysis was conducted using Design Expert software version 10.00 (STAT-EASE Inc., Minneapolis, USA).

The films with the highest UTS have been obtained through a composition of 5 g CMC, 1.5 g AMG, and 15% CEO. On the contrary, using a composition of 5 g CMC, 1 g AMG, and 30% CEO revealed the highest SB (115.41%). The highest UTS value of 13.17 MPa was obtained with a formulation consisting of 5% AMG, 1.5% CMC, and 15% CEO. Nevertheless, the maximum SB value of 115.41% was achieved with a formulation containing 5% AMG, 1% CMC, and 30% CEO. Moreover, heterogeneous microstructure and more opaque films were obtained as identified by the higher ΔE. The Differential Scanning Calorimeter results demonstrated that incorporating a CEO did not impinge on thermal stability. Furthermore, the addition of CEO led to a rise in antimicrobial activity against Salmonella enterica, Pseudomonas fluorescens, Escherichia coli, and Listeria monocytogenes.

In conclusion, combination of CMC and AMG in optimum levels, led to the production of a film with acceptable mechanical properties. Also, these films showed significant antimicrobial activity.

Monitoring regional cerebral oxygen saturation (rScO2)andhemodynamic stability (eg,meanarterial blood pressure [MABP]) in high-risk premature infants is crucial to enhance daily clinical practices in neonatal intensive care units (NICUs).

This study aimed to investigate potential differences between oxygen saturation measurements obtained via near-infrared spectroscopy (NIRS) and pulse oximetry (PO).

This pilot study enrolled20verylow-birth-weight (VLBW) prematureneonates through a non-random, available sampling approach. We gathered maternal and fetal demographic data along with clinical characteristics of the neonates. The study focused on assessing tissue and cerebral oxygenation using PO and NIRS. We specifically monitored changes in mean rScO2 and MABP at various time points: before, during, and 5 and 10 min after the administration of surfactant injection (SI) via the endotracheal tube.

The mean gestational age, neonatal birth weight, and Apgar scores at 1 and 5 min after birth were 28.44 ± 2.57 weeks, 1063 ± 246 g, 6.05 ± 2.57, and 7.94 ± 1.79, respectively. No significant differences were observed between mean rScO2 values measured by NIRS and PO before (P = 0.631), during (P = 0.722), and 5 min after (P = 0.783) SI. However, a significant difference between PO and NIRS-based rScO2 values was found 10 min after SI (96.95% vs 75.0%; P = 0.04). Additionally, there was no significant correlation between mean rScO2 and MABP recorded before, during, and after SI.

There were no differences in oxygen saturation measurements (recorded by PO) and rScO2 values (recorded by NIRS) before, during, and immediately after SI. Therefore, using PO in NICUs to assess cerebral oxygenation, autoregulation, and hypoxia appears both reasonable and cost-effective. Further multicenter studies are needed to validate the practical advantages and cost-effectiveness of NIRS as an emerging monitoring system.

Dementia involves a neuronal loss in the primary somatosensory cortex of the parietal lobe, causing dementia patients to perceive pain stimuli hardly. The function of temperature sensation declines. Studies measuring brain blood volume using near-infrared light have reported that patients suffering from dementia have less activation than healthy elderly people. However, the majority of these studies used tests related to cognitive function and the frontal lobe, and few have examined thermal sensation.
The present study aimed to investigate the effect of cold and warm stimulation on cerebral blood volume in elderly and young subjects.
This observational study measured changes in oxygenated hemoglobin concentrations in the frontal cortex during cold and warm stimulation in elderly and young subjects using a near-infrared light device. The mean and standard deviation of the change in oxygenated hemoglobin concentration before and after cold and warm stimulation, as well as the center-of-gravity values, were compared between the young and the elderly.
During warm stimulation, the younger subjects showed an increase in blood oxygenated hemoglobin levels; however, the difference was not significant. For the elderly, no change was observed during the task. The center of gravity values was lower in the young compared to the elderly which was similar to the reaction threshold. No significant changes were observed during cold stimulation. 
Thermal sensation thresholds were impaired in the elderly compared to the young; however, cerebral blood volume changes were unclear.

 Copper carbonate nanoparticles have several applications in the fields of pigments, insecticides, and fungicides. They are also used as catalysts in chemical processes and crude oil desulfurization. Fungi can biosynthesize metal nanoparticles due to their high tolerance, extracellular synthesis, simplicity of extraction, and large-scale exploitation.

 This study aimed to investigate the potential of fungal isolates (which are resistant to copper chloride with urease activity) as biocatalysts for the synthesis of copper carbonate nanoparticles. This approach was considered due to the advantages of using fungal isolates in nanoparticle biosynthesis.

 In a PDA culture medium with 25 mM copper chloride, an enrichment culture was used to isolate copper-resistant fungal isolates. Fungal isolates’ urease enzyme was qualitatively assessed using 2% urea agar-based culture media. Studies on the synthesis of copper carbonate nanoparticles and the effect of different parameters on the synthesis of these nanoparticles were conducted using a mycelium-free supernatant strategy. Field emission scanning electron microscope (FESEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) studies were used to determine the properties of calcium carbonate nanoparticles. The selected fungal isolate was identified using macroscopic and microscopic characteristics, as well as molecular analysis using amplification of the ITS1-5.8S-ITS2 gene sequences.

 Alternaria species strain ccf7 (GenBank accession number OP242500) was chosen as the superior strain for copper carbonate nanoparticle synthesis tests based on the pattern of resistance to copper chloride salt and the qualitative assessment of urease activity. Based on the findings of the electron microscope studies, spherical copper carbonate nanoparticles with an average size of 66.7 nm were synthesized after 24 hours of incubation at the optimal concentration of 45mM copper chloride, temperature of 25°C, and shaker speed of 100 rpm. The distribution of the produced nanoparticles was appropriate, as indicated by a polydispersity index (PDI) of 0.25. The strongest inhibitory impact of these copper carbonate nanoparticles was against Pseudomonas aeruginosa, with an average inhibition of 31 mm at a concentration of 50 mg/L, according to the results of their antibacterial activities.

 For the first time, the synthesis and development of a green approach for the fabrication of copper carbonate nanoparticles using the genus Alternaria have been proposed in this study.

 Chalcogenide nanoparticles (NPs), such as silver selenide NPs (Ag2Se NPs), are used as quantum dots in pharmaceutical formulations for the detection of cancer cells, as well as in solar cells, sensors, and electrical, optical, and magnetic instruments.

 The physical-chemical production of metal NPs is expensive and difficult and pollutes the environment due to the use of dangerous chemicals and by-products. Hence, green chemistry-based processes must be developed as a reliable alternative. This study investigated indigenous aquatic fungal isolates for Ag2Se NP synthesis.

 Visual examination, UV-Vis spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS) analysis, and energy-dispersive X-ray spectroscopy (EDX) tests confirmed the synthesis of Ag2Se NPs. Based on the characteristics of the colony, the microscopic features, and the polymerase chain reaction (PCR) amplification of the ITS1-5.8S-ITS2-ITS4 areas, the selected fungal isolate’s identity was established.

 The SEM analysis revealed that Cladosporium species ssf15 produced spherical Ag2Se NPs with an average diameter of 37.84 nm. The average size of NPs synthesized by the fungal isolate was determined to be 40.92 nm using the DLS analysis, and the polydispersity index (PDI) was determined to be 0.26. Based on the results, regular spherical Ag2Se NPs with correct dispersion distribution were produced using 2 mM AgNO3 and 1mM selenious acid (H2SeO3).

 The results of this research have the potential to contribute to the development of a biocompatible approach and innovative research methods for investigating the green synthesis of Ag2Se NPs using fungal isolates.

Zayandeh-rud river is the most important river in the central regions of Iran and the present study aimed to provide new insights into microplastics (MPs) pollution in surface water and sediments of this river.

Water and sediment samples were collected in July 2021 from 19 sampling sites along the river. Organics matters were removed from the samples by wet peroxide oxidation (WPO), and MPs were extracted by floatation in ZnCl2-saturated salt and filtration on a polytetrafluoroethylene (PTFE) membrane filter. Trapped MPs on the filter were counted and qualified by a stereomicroscope.

MPs were found in 13 sites from 19 sampling sites along the river. The minimum and maximum levels of MPs in water samples were 0 and 51 ± 16.5 particles/m3, respectively. MPs also were detected in the sediments of all sampling sites except the first two sampling sites (the maximum level was 58 ± 25.9 particles/kg as dry sediment). Fragments were the most common shape of MPs in both water and sediment samples. 72.3% of MPs detected in water samples were 1-5 mm in size, while this percentage for sediment was 49.2%. The five main polymer types found in water and sediment samples were polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC).

These levels of MPs in the water and sediments of Zayandeh-rud river and longtime persistence of plastics in the environment is a significant threat to environmental and human health and need serious attention to restrict MPs release into the river.

Coumarins comprise a large family of heterocyclic compounds with a benzo-a-pyrone moiety.

This study aimed to analyze the binding affinity of 3-(1H-tetrazol-5-yl) coumarin to bovine serum albumin (BSA) and calf thymus DNA (Ct-DNA) using fluorescence spectroscopy. The quenching of fluorescence was recognized during the interaction between 3-(1H-tetrazol-5-yl) coumarin and BSA, followed by a static mechanism.

The hydrogen bonds, hydrophobic interactions, and Vander Waals forces were regarded as the principal part in the 3-(1H-tetrazol-5-yl) coumarin and BSA complexation process. The fluorescence spectral characteristics demonstrated an enhancement in fluorescence intensity of the 3-(1H-tetrazol-5-yl) coumarin in the presence of ct-DNA solution.

The experimental results indicated that the 3-(1H-tetrazol-5-yl) coumarin binds to DNA via interjection, hydrogen bonds, and Vander Waals forces. This work illustrated that BSA fluorescence was quenched by 3-(1H-tetrazol-5-yl) coumarin via a static mechanism and the ct-DNA fluorescence enhancement by 3-(1H-tetrazol-5-yl) coumarin was a static process. The secondary structure of proteins changed upon drug binding.

It is deduced that 3-(1H-tetrazol-5-yl) coumarin represents a higher binding affinity to DNA compared to BSA. This finding can be useful in designing more effective new drugs with fewer side effects.

 Here, the interaction behavior between propyl acridones (PA) and calf thymus DNA (ct-DNA) has been investigated to attain the features of the binding behavior of PA with ct-DNA, which includes specific binding sites, modes, and constants. Furthermore, the effects of PA on the conformation of ct-DNA seem to be quite significant for comprehending the medicine’s mechanism of action and pharmacokinetics.

 The project was accomplished through means of absorbance studies, fluorescence spectroscopy, circular dichroism, viscosity measurement, thermal melting, and molecular modeling techniques.

 The intercalation of PA has been suggested by fluorescence quenching and viscosity measurements results while the thermal melting and circular dichroism studies have confirmed the thermal stabilization and conformational changes that seem to be associated with the binding. The binding constants of ct-DNA-PA complex, in the absence and presence of EMF, have been evaluated to be 6.19 × 104 M-1 and 2.95 × 104 M-1 at 298 K, respectively. In the absence of EMF, the ∆H0 and ∆S0 values that occur in the interaction process of PA with ct-DNA have been measured to be -11.81 kJ.mol-1 and 51.01 J.mol-1K-1, while in the presence of EMF they were observed to be -23.34 kJ.mol-1 and 7.49 J.mol-1K-1, respectively. These numbers indicate the involvement of multiple non-covalent interactions in the binding procedure. In a parallel study, DNA-PA interactions have been monitored by molecular dynamics simulations; their results have demonstrated DNA stability with increasing concentrations of PA, as well as calculated bindings of theoretical ΔG0.

 The complex formation between PA and ct-DNA has been investigated in the presence and absence of EMF through the multi spectroscopic techniques and MD simulation. These findings have been observed to be parallel to the results of KI and NaCl quenching studies, as well as the competitive displacement with EB and AO. According to thermodynamic parameters, electrostatic interactions stand as the main energy that binds PA to ct-DNA. Regarding the cases that involve the Tm of ct-DNA, EMF has proved to increase the stability of binding between PA and ct-DNA.

The manufacturing of frozen shrimp is an important industry for the economy of Thailand. The objective of this study was to use Near-Infrared (NIR) spectroscopy to determine the freshness quality, including Total Volatile Basic Nitrogen (TVB-N) and Water Holding Capacity (WHC) of white shrimp (whole and chopped shrimp) and phosphate residues of shrimp.

Sixty white shrimp samples of a size of 70-80 shrimp/kg were stored at 4 ˚C. The sample was divided into two groups by soaking in two kinds of phosphate solutions, including Sodium Tripolyphosphate (STPP) and Mixed Phosphate (NAN101). The samples were evaluated using NIR which was performed before freezing and seven days after freezing. Calibration models of the freshness and phosphate residues of fresh and frozen shrimp products were built by Partial Least Square (PLS) regression between the spectral data and the reference methods.

Satisfactory PLS results were obtained from the calibration model of TVB-N of chopped shrimp with a correlation coefficient (R) of 0.94 and Ratio of Prediction to Deviation (RPD) of 3.07. However, the NIR data indicated an unreliable prediction for the WHC (R<0.5). For the determination of phosphate residuals from STPP and NAN 101, the best calibration results were R>0.94 and RPD>3.00.

The NIR spectroscopy was feasible for monitoring the TVB-N as well as phosphate residues of shrimp products.

This study aimed to evaluate the role of the linker histone (H1) in the binding interaction between ambochlorin (Amb), and calf thymus DNA (ctDNA) as binary and ternary systems. 

The project was accomplished through the means of absorbance, fluorescence, stopped-flow circular dichroism spectroscopy, viscosity, thermal melting, and molecular modeling techniques.

Spectroscopic analysis revealed that although Amb was strongly bound to both ctDNA and ctDNA-H1, it showed a greater tendency to ctDNA in the presence of the linker histone. The obtained thermodynamic parameters revealed that both Amb-ctDNA and Amb-ctDNA-H1 interactions were spontaneous, endothermic, and entropy-favored, and hydrophobic interactions played the main role in the formation and stabilization of complexes. Analysis of the stopped-flow circular dichroism results revealed that the binding process of Amb-ctDNA and Amb-ctDNA-H1 required a time of more than 150 milliseconds to complete. Moreover, Amb-ctDNA complex formation was marginally decelerated in the presence of the linker histone. The docking results suggested that the presence of the  linker histone may alter the binding sites of Amb from ctDNA minor grooves to major grooves. 

All quenching processes were governed by a dynamic mechanism. Additionally, Amb did not stabilize or induce considerable conformational changes in ctDNA and ctDNA-H1 complex upon binding. In silico molecular docking results confirmed that Amb was bound to the double-helical ctDNA and ctDNA-H1 via ctDNA grooves. In summary, some binding properties of the interactions between Amb and ctDNA change in the presence of the linker histone.

Small molecules can bind to DNA via covalent or non-covalent interactions, which results in altering or inhibiting the function of DNA. Thus, understanding the interaction patterns of medicines or other small molecules can be very crucial. In this study, the interaction between malathion and calf thymus DNA (ctDNA), in the absence and presence of electromagnetic field (EMF) at low and high frequencies, was investigated through various spectroscopies and viscosity measurements. The interaction studies were performed by means of absorbance, circular dichroism, fluorescence spectroscopy, viscosity, thermal melting, and molecular modeling techniques. The fluorescence intensity of the ctDNA-malathion complex in the presence of EMF, has revealed quenching of fluorescence emission curves. The dynamic interaction and RLS studies have implied the changes in ctDNA-malathion complex throughout the presence of EMF which suggested that hydrophobic forces play the main role in the binding. Studies have revealed that malathion does not have any effect on binding ethidium bromide to ctDNA, which signifies the groove binding. The viscosity of ctDNA increased as the malathion concentration was enlarged. The circular dichroism technique suggested that the ellipticity values of the ctDNA-malathion complex have not increased with enhancing the malathion concentration. Molecular docking and dynamics studies have indicated a potent electrostatic interaction between ctDNA and malathion in the groove binding site.   The results of spectroscopic studies reinforced a potent interaction between malathion and ctDNA in the absence and presence of EMF which can help us for further pharmaceutical drug discoveries.

Syzygium cumini (L.) has been known to be used for diabetes treatment in traditional Indian and Chinese medicine. The present study focuses on the evaluation for glucose uptake and insulin release in vitro and characterization of phytoconstituents of the hydro-ethanolic extract of Syzygium cumini seed (SCE). Further, this report covers the molecular docking findings of the bioactive constituents on the sulfonylurea receptor 1 (SUR1).

A glucose uptake assay of SCE was used to estimate the glucose uptake from the cell lysates and the cell culture supernatants using insulin as the reference standard. Insulin release activity of SCE from RIN-5F cells was estimated using enzyme-linked immunosorbent assay. The phytoconstituents were isolated by preparative HPLC and characterized by mass spectrometry, nuclear magnetic resonance (NMR) and infrared spectroscopy. The molecular docking of bioactive constituents was carried on repaglinide bound to the SUR1.

In the presence of SCE, the glucose uptake through L6 myoblast cells increased by 19.91% at 40 µg/mL in comparison with the vehicle control (P < 0.05). Moreover, SCE showed 2.8-fold enhancement of insulin release at 40 µg/mL as compared to the vehicle controls (P < 0.05). Gallic and ellagic acids were the key phytoconstituents isolated from SCE. Molecular docking studies revealed that both gallic acid and ellagic acid bind to the repaglinide binding pocket of SUR1.

SCE increases the release of insulin and enhances glucose uptake in vitro, which may contribute to its in vivo anti-diabetic activity. The presence of ellagic acid and gallic acid in SCE may be the cause for enhanced insulin release observed with SCE following binding to SUR1.

Spectroscopic properties of Xeloda chemodrug have been studied over varying concentrations ranging between 0.001 and 10 mg/mL, using laser-induced fluorescence (LIF) spectroscopy. The alternative photoluminescence (PL) and near infrared (NIR) measurements are carried out to authenticate the obtained results by the LIF method.

The XeCl laser as the excitation coherent source with 160 mJ/pulse at 308 nm is employed for LIF measurements of the fluorophore of interest in the modular spectroscopic set-up.

Xeloda as a significant chemodrug acts as a notable fluorophore. LIF, PL and NIR spectroscopy techniques are employed to investigate the spectral properties of the chemodrug in terms of concentration. The maximum LIF peak intensity of Xeloda is achieved at λmax=410.5 nm and the characteristic concentration of CP1=0.05 mg/mL. PL signals are in good agreement with the data given by the LIF measurements. The characteristic NIR spectra of Xeloda as solid evidence of chemical bonding formation attest to fluorescence quenching at the fluorophore concentration of ~ 0.2 mg/mL. Besides, the spectral shift of fluorescence signals which is obtained in terms of fluorophore concentration- demonstrating as a diagnostic marker for the purpose of optimized chemotherapy.

Xeloda exhibits outstanding fluorescence properties over the allowable concentration in human serum (Cmax). These characteristics could benefit potential advantage of simultaneous laser-based imaging of cell-chemodrug interaction over in-vivo studies.

Saponins are well-known secondary metabolites with numerous beneficial pharmacological properties. Since the interactions of drugs with blood constituents, in particular with human serum albumin (HSA) may have a major impact on drug pharmacology, the present study designed to provide a fundamental understanding of the interaction of saponins extracted from Tribulus terrestris (typically utilized in folk medicine) with HSA in detail.

After extraction and purification of saponins; UV-Vis spectroscopy, fluorescence spectroscopy, and far-UV CD spectroscopy were used to examine the effects of saponins from Tribulus terrestris on HSA.

Thin-Layer chromatography confirmed the presence of 3 different saponins. The UV-Vis absorption, fluorescence emission and far-UV CD results displayed that saponinsfrom Tribulus terrestris could form a complex with HSA. The binding constant for the saponins–HSA complex was found to be 13.4×104M-1. The distance r between HSA and Tribulus terrestris saponins was also acquired according to the Förster theory.

Altogether, saponins can bind to HSA and change the secondary and tertiary structure of HSA moderately. The results obtained from this study can help in understanding the pharmacokinetic properties of saponins.

Membrane clogging is one of the most important problem for desalination plant operators in Iran, therefore, this study was conducted to investigate the main causes of this problem using field analysis.

In this study, six continuous membranes in a reverse osmosis (RO) pressure vessel under the 33-month service period (April 2017 to November 2019) were selected. The membranes were analyzed through visual evaluation of the outer and inner membrane surface, analyzing the damages and physical harms, oxidative stress tests, iron spot test, fouling chemical analysis using loss on ignition (LOI) tests, X-ray fluorescence (XRF), and Fourier transform infrared (FTIR) spectroscopy.

Particle size distribution in raw seawater (EC = 55 000 µs/cm, turbidity = 11 NTU) was 66.4% smaller than 1 µ and 28.3% between 1 to 1.9 µm. Physical damages were not seen on the membranes but telescopic damages were observed which was due to membrane fouling. Removal efficiencies of turbidity and silt density index (SDI) were 84% and 18%, respectively. Membrane oxidation was also seen. Most of the sediments compositions on the membranes were SiO2, Al2O3, MgO, and Fe2O3. Biological fouling was detected on the membranes surface.

Inaccurate use of chlorine neutralizer caused the residual chlorine to be present in the membrane entering water, which damaged the membrane. Accumulation of clogging agents on membrane surface showed malfunction of pretreatment function, therefore, revision of design and operation of units is necessary. Biological fouling is due to non-effective pre-chlorination of drinking water. Metallic compounds sedimentation on the membrane is due to improper use of anti-fouling chemicals. High SDI in the influent shows the need to change the cartridge filters.

Currently, the most available treatment for acute ischemic stroke (AIS) is thrombolytic therapy with recombinant tissue plasminogen activator (r-TPA). A challenge in r-TPA therapy is the prediction of recovery in each case.

The aim was to find a possible relationship between the cerebral oximetry indexes and the clinical outcome of r-TPA therapy to assess the cerebral oximetry as a non-invasive monitoring agent for therapy.

The inclusion criteria were all patients with AIS who received r-TPA. The neurologic status was evaluated based on the national institutes of health stroke scale (NIHSS) score at arrival, and after a period of 24 hours. In addition, the levels of brain oxygenation in both hemispheres were measured before and continuously over the first 24 hours after r-TPA injection, using an oximetric sensor in the frontal lobes. The clinical success was defined as a 4-point improvement from the baseline NIHSS.

Total 44 patients with the mean age of 58.2 ± 2.18 years were enrolled, of whom 68.18% were male. Twenty-eight patients remained clinically unimproved and 16 patients were improved. A significant difference was found in the mean surface area under the brain oximetric curve in the 24 hour, in the affected hemisphere in the improved group, compared to the unimproved group (P = 0.007). There was a significant difference between the mean increase in brain oxygenation within 24 hours in the improved and unimproved groups (P = 0.002).

It is likely that, The cerebral oximetry could contribute to predict the likelihood of r-TPA prognosis in patients with AIS.