Preparation, Characterization and Antibacterial Properties of Silver-Chitosan Nanocomposites Using Different Molecular Weight Grades of Chitosan

Purpose: To study the effect of chitosan molecular weight on the physicochemical and antibacterial properties of silver-chitosan nanoparticles.Methods: A series of silver-chitosan nanoparticles of different sizes were produced using various molecular weight (MW) grades of chitosan by an aqueous chemical reduction method. The nanoparticles were characterized by ultraviolet-visible absorption spectroscopy (UV-Vis), scanningelectron microscopy (SEM), differential scanning calorimetry (DSC), dynamic light scattering (DLS) and laser Doppler electrophoresis (LDE). The antibacterial properties of the nanoparticles were also evaluated by agar diffusion method.Results: The size of the silver-chitosan nanoparticles, ranging from 21.9 to 175.3 nm, was influenced by chitosan MW as well as by other process conditions. Although, the nanoparticles were not stable in liquid form, they however showed good stability in the solid state due to their low zeta potential. SEM images indicate that the nanoparticles were spherical. The antibacterial activity of the nanoparticles against Staphylococcus aureus increased with decrease in particle size owing to increase in surfacearea. The smallest particle size (21.9 nm) was obtained by using high chitosan MW at 4 °C and a stirring speed of 800 rpm.Conclusion: Chitosan is an effective agent for the preparation of silver nanoparticles. The size of the nanoparticles can be modulated by varying both chitosan MW and process conditions such as temperature and stirring speed

Evaluating the toxicity of permeability enhanchers of polyethylene glycol brij ethers surfactants group on cellular membranes and some of their physicochemical properties

The aim of this study is to evaluate the effect of polyethylene glycol brij ethers surfactants group on red blood cells as a model for biological membranes. Also in this study, physicochemical properties including emulsification index (E24), foam producing activity (Fh) and critical micelle concentration (cmc) were studied. Surfactant solutions were prepared in McIvan’s buffer in specific concentrations. 0.2 ml of red blood cells (RBC) was mixed with 0.2 ml of each surfactant solution. The four surfactant solutions had each been incubated differently at two different temperatures for three different times. Each test was done six times. The results were presented as mean absorbance ± the standard deviation. E24, Fh and cmc were also determined for each surfactant solution. All of the surfactant solutions showed hemolytic activity. In comparison with the four studied surfactants, brij 56 had the highest hemolytic effect and brij 72 the lowest. The values of E24 and Fh had good correlation with hydrophilic-lipophilic balance values. According to the results of this study, brijs should be used at concentrations lower than cmc in formulations. Also, according to the results, the use of brijs with low hemolytic effect such as brij 72, is preferred in pharmaceutical preparations.Key words: Brij, biological membrane, hemolysis, hydrophile-lipophile balance (HLB)

Presence of lead in opium.

Opium addiction is a common form of addiction in Middle East countries such as Iran. Recently several reports suggested some kinds of pathologic findings such as abdominal pain, nephropathy, and anemia in opium addict patients. Such pathologic findings suggest lead poisoning in the patients. In this study, the concentration of lead in 10 opium samples was evaluated. The mean concentration of lead in the opium samples was 1.88 ppm. This may explain some of the pathologic findings found in addict patients. The authors would suggest further investigations to evaluate the lead concentration in opium addicts' sera and also routine screening for lead poisoning in opium addict patients

Embedded Research::a promising way to create evidence-informed impact in public health?

Background Embedded research (ER) is recognized as one way to strengthen the integration of evidence into public health (PH) practice. In this paper, we outline a promising example of the co-production of research evidence between Fuse, the UKCRC Centre for Translational Research in Public Health and a local authority (LA) in north east England. Methods We critically examine attempts to share and use research findings to influence decision-making in a LA setting, drawing on insights from PH practitioners, managers, commissioners and academic partners involved in this organizational case study. We highlight what can be achieved as a co-located embedded researcher. Results The benefits and risks of ER are explored, alongside our reflections on the added value of this approach and the institutional prerequisites necessary for it to work. We argue that while this is not a new methodological approach, its application in PH as a way to facilitate evidence use is novel, and raises pragmatic and theoretical questions about the nature of impact and the extent to which it can be engineered. Conclusion With increased situated understanding of organizational culture and norms and greater awareness of the socio-political realities of PH, ER enables new co-produced solutions to become possible

"It was the whole picture" a mixed methods study of successful components in an integrated wellness service in North East England

Background A growing number of Local Authorities (LAs) have introduced integrated wellness services as part of efforts to deliver cost effective, preventive services that address the social determinants of health. This study examined which elements of an integrated wellness service in the north east of England were effective in improving health and wellbeing (HWB). Methods The study used a mixed-methods approach. In-depth semi-structured interviews (IVs) were conducted with integrated wellness service users (n = 25) and focus groups (FGs) with group based service users (n = 14) and non-service users (n = 23) to gather the views of stakeholders. Findings are presented here alongside analysis of routine monitoring data. The different data were compared to examine what each data source revealed about the effectiveness of the service. Results Findings suggest that integrated wellness services work by addressing the social determinants of health and respond to multiple complex health and social concerns rather than single issues. The paper identifies examples of ‘active ingredients’ at the heart of the programme, such as sustained relationships, peer support and confidence building, as well as the activities through which changes take place, such as sports and leisure opportunities which in turn encourage social interaction. Wider wellbeing outcomes, including reduced social isolation and increased self-efficacy are also reported. Practical and motivational support helped build community capacity by encouraging community groups to access funding, helped navigate bureaucratic systems, and promoted understanding of marginalised communities. Fully integrated wellness services could support progression opportunities through volunteering and mentoring. Conclusions An integrated wellness service that offers a holistic approach was valued by service users and allowed them to address complex issues simultaneously. Few of the reported health gains were captured in routine data. Quantitative and qualitative data each offered a partial view of how effectively services were working

Genomic Instability Is Associated with Natural Life Span Variation in Saccharomyces cerevisiae

Increasing genomic instability is associated with aging in eukaryotes, but the connection between genomic instability and natural variation in life span is unknown. We have quantified chronological life span and loss-of-heterozygosity (LOH) in 11 natural isolates of Saccharomyces cerevisiae. We show that genomic instability increases and mitotic asymmetry breaks down during chronological aging. The age-dependent increase of genomic instability generally lags behind the drop of viability and this delay accounts for ∼50% of the observed natural variation of replicative life span in these yeast isolates. We conclude that the abilities of yeast strains to tolerate genomic instability co-vary with their replicative life spans. To the best of our knowledge, this is the first quantitative evidence that demonstrates a link between genomic instability and natural variation in life span

Genome-Wide Association Analysis of Oxidative Stress Resistance in Drosophila melanogaster

Background: Aerobic organisms are susceptible to damage by reactive oxygen species. Oxidative stress resistance is a quantitative trait with population variation attributable to the interplay between genetic and environmental factors. Drosophila melanogaster provides an ideal system to study the genetics of variation for resistance to oxidative stress. Methods and Findings: We used 167 wild-derived inbred lines of the Drosophila Genetic Reference Panel for a genomewide association study of acute oxidative stress resistance to two oxidizing agents, paraquat and menadione sodium bisulfite. We found significant genetic variation for both stressors. Single nucleotide polymorphisms (SNPs) associated with variation in oxidative stress resistance were often sex-specific and agent-dependent, with a small subset common for both sexes or treatments. Associated SNPs had moderately large effects, with an inverse relationship between effect size and allele frequency. Linear models with up to 12 SNPs explained 67–79 % and 56–66 % of the phenotypic variance for resistance to paraquat and menadione sodium bisulfite, respectively. Many genes implicated were novel with no known role in oxidative stress resistance. Bioinformatics analyses revealed a cellular network comprising DNA metabolism and neuronal development, consistent with targets of oxidative stress-inducing agents. We confirmed associations of seven candidate genes associated with natural variation in oxidative stress resistance through mutational analysis. Conclusions: We identified novel candidate genes associated with variation in resistance to oxidative stress that hav

Non-aqueous titration for the determination of Azelaic Acid: Introduction and method validation

Alpha-hydroxylic acids are widely used in the treatment and control of skin disorders. Azelaic acid is a naturally occurring alpha-hydroxy acid that can be formed endogenously from long-chain dicardoxylic acids, metabolism of oleic acid or omega oxidation of mono carboxylic acids. It shows bacteriostatic and bactericidal activities against aerobic and anaerobic microorganisms present on acne-bearing skins. The beneficial effects of Azelaic acid have been lead to different pharmaceutical formulations such as creams, gels, etc. HPLC and GC techniques are mostly used for the determination of Azelaic acid in plasma. These techniques are very accurate but, they are expensive and time consuming due to the lack of chromophore and consequently the necessity of pre-column sample preparation. For the determination of Azelaic acid in pharmaceutical dosage forms, a simple method with suitable accuracy and precision is needed. In this research, non-aqueous titration was used for the determination of Azelaic acid. For this purpose, Azelaic acid was titrated by sodium methoxide in the presence of thymol blue. The results of method validation by considering various parameters showed the accuracy of the suggested method in the determination of Azelaic acid in pharmaceutical formulations. Keywords: Azelaic acid, Non-aqueous titration, Method validatio