From Green Synthesis to Diverse Applications: Exploring the Environmentally Viable Potential of Silver Nanocomposites with Biodegradable Polymers.

In the realm of environmentally conscious materials science, the integration of silver nanoparticles (AgNPs) with biodegradable polymers to form innovative nanocomposites has sparked notable discourse and research. This review delves comprehensively into the synthesis, properties, and environmental implications of said AgNPs/biodegradable polymer nanocomposites. Leveraging the unique physicochemical attributes of silver nanoparticles, these nanocomposites are portrayed as promising platforms for delivery, sensing, and antimicrobial applications. The nanocomposites made of AgNPs with biodegradable polymers, however, extend beyond utility, demonstrating a commitment to minimizing ecological impact. Contrary to traditional non-degradable polymers that litter our environments and oceans, these green alternatives yield lesser waste, reduce energy use, and limit the emission of volatile organic compounds, thereby aligning with global efforts towards sustainability. Our review strives to substantiate the environmental viability of these nanocomposites, whilst elaborating on their diverse commercial potential.

Antibacterial Properties of Ag-Cu Alloy Nanoparticles Against Multidrug-Resistant Pseudomonas aeruginosa Through Inhibition of Quorum Sensing Pathway and Virulence-Related Genes.

Objective: To evaluate the application of Ag-Cu NPs as quorum sensing (QS) inhibitors and attenuate virulence expression to overcome the global crisis of multidrug-resistant (MDR) P. aeruginosa. Methods: Ag-Cu NPs were synthesized by co-reduction of silver-nitrate and copper-nitrate (Ag:Cu = 1:1 0.75 µM). In this cross-sectional study, a total of eighty clinical strains of P. aeruginosa were collected from patients with burns. The antibacterial and resistance pattern of the clinical isolated was determined using the microdilution and Kirby Bauer disk methods. The effect of sub-MIC of Ag-Cu NPs on the expression of lasI, exoS and toxA in five clinical isolates of imipenem-resistant P. aeruginosa was performed using qRT-PCR. Results: The characterization methods confirm the formation of the Ag-Cu alloy NPs with agglomerated spherical morphology and particle sizes of about 30-40 nm. We observed that the MIC and MBC of Ag-Cu alloy NPs against MDR P. aeruginosa was found to be 2.5 and 5 µg ml-1, respectively. The effects of a sub-inhibitory concentration of Ag-Cu NPs on MDR P. aeruginosa QS and virulence-related genes showed that the expression level of QS regulatory and virulence genes significantly decreased in both MDR P. aeruginosa and reference strain under Ag-Cu sub-MIC treatment. Conclusion: Ag-Cu NPs could be potentially used as a promising QS inhibitor and anti-virulence compound against P. aeruginosa.

Fe3O4@SiO2@CeO2 as a Potential Nanomagnetic Carrier for Oral Delivery System and Release of Celecoxib.

AIMS AND OBJECTIVE: In this study, an attempt was made to synthesize, characterize, and develop many applications of functionalized rare metal oxide nanoparticles. Herein, a new strategy for drug delivery is developed to functionalize magnetite nanoparticles to improve their performances in the delivery of celecoxib. MATERIALS AND METHODS: Magnetite Fe3O4@SiO2 nanoparticles are synthesized by the sol-gel method. The surface of the hydroxyl groups was extended by treating with cerium nitrate salt; finally, sodium hydroxide was anchored to the surface hydroxyl groups to produce cerium oxidefunctionalized Fe3O4@SiO2@CeO2 magnetic nanoparticles (FSC). The synthesized sample was characterized by FT-IR, FESEM, VSM, TGA, and XRD. Afterward, the functionalized nanoparticles were examined in the delivery of celecoxib as an active drug model involving cerium oxide and hydroxyl functional groups. RESULTS: For this purpose, the amount of loading/release of the drug was investigated in different amounts of nanocomposite and pH values. CONCLUSION: The results of the present investigation indicate that the formulations (mFSC=5 mg, pH=3.3) can be considered as best among various formulations with respect to particle size, entrapment efficiency, and in-vitro successful drug release.

Microwave-assisted Synthesis of Novel Pyrazole Derivatives and their Biological Evaluation as Anti-Bacterial Agents.

AIMS AND OBJECTIVES: Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol. MATERIALS AND METHODS: The structural features of the synthesized compounds were characterized by melting point, FT-IR, 1H, 13C NMR and elemental analysis. RESULTS: The antibacterial activities of the synthesized pyrazoles were evaluated against three gram-positive bacteria, such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium. CONCLUSION: All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain, and none of them demonstrated antibacterial activity against E. coli.

Controlled Growth and Characterization Ag/ZnO Nanotetrapods for Humidity Sensing.

AIM AND OBJECTIVE: Ultrafine Ag/ZnO nanotetrapods (AZNTP) have been prepared successfully using silver (I)-bis (oxalato) zinc complex and 1, 3-diaminopropane (DAP) with a phase separation system, and have been injected into a diethyl/water solution. MATERIALS AND METHODS: This crystal structure and lattice constant of the AZNTP obtained were investigated by means of a SEM, XRD, TEM and UV-vis spectrum. RESULTS: The results of the present study demonstrated the growth and characterization AZNTP for humidity sensing and DAP plays a key role in the determination of particle morphology. AZNTP films with 23 nm in arm diameter have shown highly sensitive, quick response sensor material that works at room temperature.

Green synthesis of gold nanoparticles using Stevia rebaudiana leaf extracts: Characterization and their stability.

Various methods invented and developed for the synthesis of gold nanoparticles that increases daily consumed. According to this method, including potential environmental pollution problems and the complexity of the synthesis, in this study, the feasibility of using the leaves extract of Stevia rebaudiana (SR) for the reduction of gold ions to nanoparticles form have been studied. Stevia leaves were used to prepare the aqueous extract for this study. Gold nanoparticles were characterized with different techniques such as UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 5 to 20 nm. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary amine group (NH2), carbonyl group, OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles with size of 17 nm. The scanning electron microscopy (SEM) implies the right of forming gold nanoparticles. The results, confirm that gold nanoparticles have synthesized by the leaves extract of S. rebaudiana (SR).

A study on the stability and green synthesis of silver nanoparticles using Ziziphora tenuior (Zt) extract at room temperature.

Biomolecules present in plant extracts can be used to reduce metal ions to nanoparticles in a single-step green synthesis process. This biogenic reduction of metal ion to base metal is quite rapid, readily conducted at room temperature and pressure, and easily scaled up. Mediated Synthesis by plant extracts is environmentally benign. The involved reducing agents include the various water soluble plant metabolites (e.g. alkaloids, phenolic compounds, terpenoids) and co-enzymes. Silver (Ag) nanoparticles have the particular focus of plant-based syntheses. Extracts of a diverse range of Ziziphora tenuior (Zt) have been successfully used in making nanoparticles. The aim of this study was to investigate the antioxidant properties of this plant and its ability to synthesize silver nanoparticles. Z.tenuior leaves were used to prepare the aqueous extract for this study. Silver nanoparticles were characterized with different techniques such as UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 8 to 40 nm. FT-IR spectroscopy revealed that silver nanoparticles were functionalized with biomolecules that have primary amine group (NH2), carbonyl group, -OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of silver nanoparticles with size of 38 nm. In addition to plant extracts, live plants can be used for the synthesis. Here were view the methods of making nanoparticles using plant extracts. The scanning electron microscopy (SEM) implies the right of forming silver nanoparticles. The results of TEM, SEM, FT-IR, UV-VIS and XRD confirm that the leaves extract of Zt can synthesis silver nanoparticles.

Facile green synthesis of silver nanoparticles using seed aqueous extract of Pistacia atlantica and its antibacterial activity.

In the present work, we describe the synthesis of silver nanoparticles (Ag-NPs) using seed aqueous extract of Pistacia atlantica (PA) and its antibacterial activity. UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) were performed to ascertain the formation of Ag-NPs. It was observed that the growths of Ag-NPs are stopped within 35 min of reaction time. The synthesized Ag-NPs were characterized by a peak at 446 nm in the UV-visible spectrum. XRD confirmed the crystalline nature of the nanoparticles of 27 nm size. The XRD peaks at 38°, 44°, 64° and 77° can be indexed to the (111), (200), (220) and (311) Bragg's reflections of cubic structure of metallic silver, respectively. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of used drugs against bacterial diseases. The scanning electron microscopy (SEM), indicated that, the most strains of S. aureus was damaged and extensively disappeared by addition of Ag-NPs. The results confirmed that the (PA) is a very good eco friendly and nontoxic source for the synthesis of Ag-NPs as compared to the conventional chemical/physical methods.

Effects of music on cardiovascular responses in men with essential hypertension compared with healthy men based on introversion and extraversion.

INTRODUCTION: The present research investigated the effects of two different types of music on cardiovascular responses in essential hypertensive men in comparison with healthy men based on introversion and extraversion. METHODS: One hundred and thirteen hypertensive men referred to Madani Heart Hospital in Tabriz completed the NEO-FFI Questionnaire and after obtaining acceptable scores were classified in four groups: introvert patients, extravert patients, introvert healthy subjects, and extravert healthy subjects (each group with 25 samples with age range 31-50). Baseline blood pressure and heart rate of each subject was recorded without any stimulus. Then subjects were exposed to slow-beat music and blood pressure and heart rate were recorded. After15 minute break, and a little cognitive task for distraction, subjects were exposed to fast-beat music and blood pressure and heart rate were recorded again. RESULTS: Multivariate analysis of covariance (MANCOVA) test showed that extravert patient subjects obtained greater reduction in systolic blood pressure and heart rate after presenting slow-beat music compared with introvert patients (P= 0.035, and P= 0.033 respectively). And extravert healthy subjects obtained greater reduction in heart rate after presenting slow-beat music compared with introvert healthy subjects (P= 0.036). However, there are no significant differences between introvert and extravert groups in systolic and diastolic blood pressure and heart rate after presenting fast-beat music. CONCLUSION: Based on our results, introvert subjects experience negative emotions more than extravert subjects and negative emotions cause less change in blood pressure in these subjects compared with extravert subjects.

Preparation of ZnO/Ag nanocomposite and coating on polymers for anti-infection biomaterial application.

ZnO/Ag nanocomposites coated with polyvinyl chloride (PVC) were prepared by chemical reduction method, for anti-infection biomaterial application. There is a growing interest in attempts in using biomolecular as the templates to grow inorganic nanocomposites in controlled morphology and structure. By optimizing the experiment conditions, we successfully fabricated high yield of ZnO/Ag nanocomposite with full coverage of high-density polyvinyl chloride (PVC) coating. More importantly, ZnO/Ag nanocomposites were shown to significantly inhibit the growth of Staphylococcus aureus in solution. It was further shown that ZnO/Ag nanocomposites induced thiol depletion that caused death of S. aureus. The coatings were fully characterized using techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Most importantly, compared to uncoated metals, the coatings on PVC promoted healthy antibacterial activity. Importantly, compared to ZnO-Ag -uncoated PVC, the ZnO/Ag nanocomposites coated was approximately triplet more effective in preventing bacteria attachment. The result of Thermal Gravimetric Analysis (TGA) indicates that, the ZnO/Ag nanocomposites are chemically stable in the temperature range from 50 to 900°C. This result, for the first time, demonstrates the potential of using ZnO/Ag nanocomposites as a coating material for numerous anti-bacterial applications.

Effects of emotional stimuli on cardiovascular responses in patients with essential hypertension based on brain/behavioral systems.

INTRODUCTION: Effects of emotional stimuli on hemodynamics in patients with essential hypertension based on brain/behavioral systems have not been studied broadly. METHODS: Eighty five essential hypertensive male patients who had completed Carver-White BIS/BAS scale were enrolled to the study. Later, 25 BIS and 25 BAS patients were selected and their blood pressure and heart rate were recorded prior to stimuli induction. Participants were then exposed to stressor pictures. After that, 15 minutes of relaxation and cognitive tasks were performed. Finally, the participants were exposed to pleasant pictures. The blood pressure and heart rate were recorded after presenting of 2 stimuli. RESULTS: Our study showed that BIS patients achieved higher scores in diastolic blood pressure and heart rate in comparison with BAS patients after presenting stressful stimuli. Also, BAS patients achieved lower scores in systolic blood pressure and heart rate in comparison with BIS patients after presenting pleasant stimuli. CONCLUSION: In summary, BIS patients experience negative emotions more than BAS patients. Therefore, the role of induced mood states is important in relation to physical health.

A direct comparison of nanosilver particles and nanosilver plates for the oxidation of ascorbic acid.

We study of spherical silver nanoparticles of different size and Ag nanoplates were grown at zinc tin oxide (ZTO) surface and characterized using SEM. The application of different electrodes in voltammetry for determination ascorbic acid indicated that oxidation of this biomolecule occurs at these electrodes in diffusion controlled process. Ag nanoplates modified zinc tin oxide electrodes exhibit at least two to three times higher current than spherical nanosilver particles. The observed behavior suggests that Ag nanoplates exhibit higher electrocatalytic activity than spherical silver nanoparticles. The reason for such behavior may be due to lattice plane as well as due to more available surface edges. As dimensions of nanoplates are increased surface area in the case of nanoplates also appears to play a significant role.

Intravitreal bevacizumab vs. sham treatment in acute branch retinal vein occlusion with macular edema: results at 3 months (Report 1).

BACKGROUND: The goal of this work is to compare the visual and anatomical (central macular thickness; CMT) outcomes of intravitreal bevacizumab (IVB) injections relative to sham treatment in eyes with acute (less than 3 months in duration) branch retinal vein occlusion (BRVO). METHODS: In a double-masked randomized clinical trial (RCT), patients with acute BRVO were randomly assigned to one of two treatment groups: IVB (two injections of 1.25 mg IVB 6 weeks apart) or sham treatment. Primary outcome measures included changes in best-corrected visual acuity (BCVA) and CMT in optical coherence tomography (OCT) during follow-up (FU) examinations. Any complications secondary to injections were considered secondary outcomes. FU results after 6 and 12 weeks are reported. RESULTS: Eighty-one eyes (43 OD) of 81 patients (47 females) were enrolled in the study. Forty-two patients were enrolled in the IVB group, and 39 patients were enrolled in the sham group. Visual acuity and CMT improved in the IVB group after week 6 (two Snellen lines and 262 µm, respectively) and week 12 (three Snellen lines and 287 µm, respectively). After week 6, visual improvements in the IVB group were significantly increased relative to that of the sham group. However, visual improvements at week 12 were not significantly different between the two groups (1.5 Snellen lines visual improvement in the sham group at week 12). CONCLUSIONS: In acute BRVO, two IVB injections resulted in significant improvement of vision and CMT at 6 weeks relative to the sham group. However, the visual improvements in the IVB group were not significantly different from those in the sham group at 12 weeks. IVB injections accelerate an initial improvement of visual acuity but do not have any significant effects on vision after 12 weeks.