Plasmonic Oleylamine-Capped Gold and Silver Nanoparticle-Assisted Synthesis of Luminescent Alloyed CdZnSeS Quantum Dots

We report on a novel strategy to tune the structural and optical properties of luminescent alloyed quantum dot (QD) nanocrystals using plasmonic gold (Au) and silver (Ag) nanoparticles (NPs). Alloyed CdZnSeS QDs were synthesized via the organometallic synthetic route with different fabrication strategies that involve alternative utilization of blends of organic surfactants, ligands, capping agents, and plasmonic oleylamine (OLA)-functionalized AuNPs and AgNPs. Ligand exchange with thiol l-cysteine (l-cyst) was used to prepare the hydrophilic nanocrystals. Analysis of the structural properties using powder X-ray diffraction revealed that under the same experimental condition, the plasmonic NPs altered the diffractive crystal structure of the alloyed QDs. Depending on the fabrication strategy, the crystal nature of OLA-AuNP-assisted CdZnSeS QDs was a pure hexagonal wurtzite domain and a cubic zinc-blende domain, whereas the diffraction pattern of OLA-AgNP-assisted CdZnSeS QDs was dominantly a cubic zinc-blende domain. Insights into the growth morphology of the QDs revealed a steady transformation from a heterogeneous growth pattern to a homogenous growth pattern that was strongly influenced by the plasmonic NPs. Tuning the optical properties of the alloyed QDs via plasmonic optical engineering showed that the photoluminescence (PL) quantum yield (QY) of the AuNP-assisted l-cyst-CdZnSeS QDs was tuned from 10 to 31%, whereas the PL QY of the AgNP-assisted l-cyst-CdZnSeS QDs was tuned from 15 to 90%. The low PL QY was associated with the surface defect state, while the remarkably high PL QY exhibited by the AgNP-assisted l-cyst-CdZnSeS QDs lends strong affirmation that the fabrication strategy employed in this work provides a unique opportunity to create single ensemble, multifunctional, highly fluorescent alloyed QDs for tailored biological applications

Phytochemical and antimicrobial screening of the crude extracts from the root, stem bark and leaves of Vitellaria paradoxa (GAERTN. F)

The root, stem and leaves of Vitellaria paradoxa, belonging to the Sapotaceae family and which have some ethnomedicinal applications were studied. Phytochemical screening of the plant parts reveals thepresence of carbohydrates (free reducing sugars, ketoses, pentoses and starch), saponins, steroids, tannins and alkaloids. The antimicrobial screening of the crude methanol extract carried out in vitro onthe following clinical isolates; Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pnuemoniae and Salmonella typhi showed that the crude methanol extracts hadwider range of activity on these organisms than the petroleum ether extracts. The crude stem extracts inhibited the growth of P. aeruginosa, K. pneumoniae, B. cereus and S. typhi at concentration of 50mg/ml while the leaf had a minimal inhibition concentration (MIC) of 70 mg/ml on S. aureus, E. coli and S. typhi. The root had an MIC of 60 mg/ml on S. aureus, E. coli, P. aeruginosa, K. pneumoniae and S.typhi. The MBC in all the cases were slightly higher than the MIC and was lowest in the stem extracts which indicates that the stem bark may contain the most active components

A localized surface plasmon resonance-amplified immunofluorescence biosensor for ultrasensitive and rapid detection of nonstructural protein 1 of Zika virus

publishe

Test-retest reliability of IPAQ environmental- module in an African population

<p>Abstract</p> <p>Background</p> <p>There is overwhelming evidence of the benefits of physical activity and the physical environment is increasingly recognized as a promising determinant of physical activity participation. The influence of the environment on physical activity has not been evaluated among black Africans and no specific measure exists for assessing environmental factors related to physical activity in an African environment. The IPAQ E- module was designed to assess environmental factors for physical activity participation and was considered to be relevant to all countries regardless of the stage of economic development. The objective of this study was to assess the test- retest reliability of IPAQ E- module in an African population.</p> <p>Methods</p> <p>One hundred and three clinical students of a University in Nigeria were invited to participate in the reliability testing of IPAQ E- module. Sixteen of the 17- items on the environmental measure were assessed for test- retest reliability using intraclass correlation coefficient (ICC) with 95% Confidence interval (CI) overall and by gender. The measure addressed items regarding residential density, access to destinations, neighborhood infrastructures, aesthetic qualities, social environment, street connectivity and neighborhood safety.</p> <p>Results</p> <p>Of the total respondents, 51.5% were males and 48.5% were females. Overall, the intraclass correlation coefficient (ICC) ranged from 0.43 to 0.91. The item regarding many interesting things to look at (aesthetic) produced the overall highest reliability score (ICC = 0.91, 95% CI = 0.86 – 0.94), while the item regarding safety from crime during the day (neighborhood safety) produced the lowest overall score (ICC = 0.43, 95% CI = 0.26 – 0.57). Reliability of items on neighborhood infrastructures ranged between substantial agreement to almost perfect agreement overall (ICC = 0.66 – 0.88) and by gender (male- ICC = 0.68 – 0.90 and female- ICC = 0.63 – 0.86). The access to destination items (ICC = 0.49 – 0.74), social environment (ICC = 0.62) and street connectivity (ICC = 0.78) all had acceptable reliability overall. Meaningful differences were found between males and females on two items on neighborhood safety and one item on access to destinations.</p> <p>Conclusion</p> <p>The test- retest of IPAQ E- module resulted in moderate to almost perfect agreement for most of the items with few meaningful differences by gender. Environmental items of physical activity in an African population exhibited reliability similar to that in other environments. These results suggest that IPAQ E- module may be a useful measure for assessing environmental correlates of physical activity among population in Africa.</p

Understanding the risk of emerging bacterial resistance to over the counter antibiotics in topical sore throat medicines

Aims The aims of this study were to explore the development of bacterial resistance and cross‐resistance in four common human pathogens following realistic exposure to antibiotics found in over‐the‐counter (OTC) sore throat medicines: gramicidin, neomycin, bacitracin and tyrothricin. Methods and Results Bacterial exposure to in‐use (concentration in the product before use) and diluted concentration (i.e. during use ) of antibiotic where conducted in broth for 24 h or until growth was visible. The changes in bacterial susceptibility profile before and after exposure was determined using standardized ISO microdilution broth. Antibiotic testing was performed according to EUCAST guidelines. We demonstrated that test bacteria were able to survive exposure to the in‐use concentrations of some antibiotics used in OTC medicines. Exposure to during use concentrations of bacitracin resulted in stable increase in minimal inhibitory concentration (MIC) (>8‐fold) in Staphylococcus aureus and Acinetobacter baumannii . Exposure to tyrothricin resulted in a stable increase in MIC (2·4‐fold) in Klebsiella pneumoniae , and exposure to neomycin resulted in a stable increase MIC (5000‐fold higher than the baseline) in Streptococcus pyogenes . Clinical cross‐resistance to other antibiotics (ciprofloxacin, fusidic acid, gentamicin, cefpodoxime, amoxicillin/clavulanic acid and cefotaxime) was also demonstrated following exposure to bacitracin or tyrothricin. Bacitracin exposure lead to a stable bacterial resistance after 10 passages. Conclusions Our results indicate that OTC antibiotic medicines have the potential to drive resistance and cross‐resistance in vitro . Significance and Impact of the Study Tackling antibiotic resistance is a high worldwide priority. It is widely accepted that the overuse and misuse of antibiotics increase the risk of the development and spread of antibiotic resistance within communities. A number of OTC sore throat products, widely available across the world for topical use in respiratory indications, contain locally delivered antibiotics. Our findings showed that these antibiotics in OTC medicines present a risk for emerging cross‐resistance in a number of bacterial respiratory pathogens

Social Implications of Female Circumcision for Human Rights

Female Circumcision is carried out for reasons that include cultural and gender identity; social and cultural control of women\u27s sexuality and reproductive functions; beliefs about hygiene, aesthetics, health and religion. There is the fear that the girl might bring shame to the family by being sexually active and becoming pregnant before marriage. Female Circumcision is a manifestation of gender-based human rights violations, which aim to control women\u27s sexuality and autonomy. It is one of the many forms of social injustice, which women suffer worldwide. Female Circumcision is an act of barbarism, savagery, torture, and maiming, which deprives women of their femininity, especially wotj regard to sexual sensitivity and pleasure. It is a denial of the fundamental and inherent human rights of women to an intact body, physical and moral integrity, freedom from discrimination and the highest standard of health. Cultural claims should not be invoked to justify the violation of human rights

An ultrasensitive SiO2-encapsulated alloyed CdZnSeS quantum dot-molecular beacon nanobiosensor for norovirus

AbstractUltrasensitive, rapid and selective diagnostic probes are urgently needed to overcome the limitations of traditional probes for norovirus (NV). Here, we report the detection of NV genogroup II via nucleic acid hybridization technology using a quantum dot (QD)-conjugated molecular beacon (MB) probe. To boost the sensitivity of the MB assay system, an ultrasensitive QD fluorophore with unique optical properties was synthesized, characterized and exploited as a fluorescence signal generator. Alloyed thioglycolic (TGA)-capped CdZnSeS QDs with a high photoluminescence (PL) quantum yield (QY) value of 92% were synthesized, and a modified silanization method was employed to encapsulate the thiol-capped QDs in a silica layer. The resulting highly luminescent alloyed SiO2-coated CdZnSeS QDs had a remarkable PL QY value of 98%. Transmission electron microscopy and dynamic light scattering confirmed the monodispersity of the alloyed nanocrystals, and zeta potential analysis confirmed their colloidal stability. Powder X-ray diffraction and PL lifetime measurements confirmed the surface modification of the QDs. The alloyed TGA-capped and SiO2-coated CdZnSeS QD-conjugated MB bioprobes detected extremely low concentrations of NV RNA. Ultrasensitive detection of low concentrations of NV RNA with a limit of detection (LOD) of 8.2copies/mL in human serum and a LOD of 9.3 copies/mL in buffer was achieved using the SiO2-coated CdZnSeS QD-MB probes, an increase in sensitivity of 3-fold compared with the detection limit for NV RNA using TGA-capped CdZnSeS QD-MBs. The additional merits of our detection system are rapidity, specificity and improved sensitivity over conventional molecular test probes

Fluorometric virus detection platform using quantum dots-gold nanocomposites optimizing the linker length variation

autho

Environmental factors associated with overweight among adults in Nigeria

Background: Understanding environmental factors related to obesity can inform interventions for the world wide obesity epidemic, yet no study has been conducted in this context in Africa. This study examined associations between neighbourhood environment variables and overweight in Nigerian adults. Methods: A total of 1818 randomly selected residents (age: 20-65 years, 40% female, 31% overweight and 61.2% response) living in high and low socioeconomic (SES) neighbourhoods in Metropolitan Maiduguri, Nigeria, participated in a cross-sectional study. Anthropometric measurements of height and weight and an interview-assisted self-reported measure of 16 items of perceived neighborhood environments were conducted. The primary outcome was overweight (body mass index [BMI] > or = 25 kg/m(2)) vs. normal weight (BMI = 18.5-24.9 kg/m(2)). Results: After adjustment for sociodemographic variables, overweight was associated with distant access to commercial facilities (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.02-2.18), poor neighbourhood aesthetics (OR, 1.58; 95% CI, 1.16-2.09), perceiving garbage and offensive odours in the neighbourhood (OR, 1.41; 95% CI, 1.05-1.89) and feeling unsafe from crime at night (OR, 1.47; 95% CI, 1.13-1.91) and unsafe from traffic (OR, 1.56; 95% CI, 1.17-2.07) in the total sample. Significant interactions regarding overweight were found between gender and four environmental variables, with low residential density (OR, 1.39; 95% CI, 1.02-1.93) and poorly maintained pedestrian pathways (OR, 1.89; 95% CI, 1.13-3.17) associated with overweight in men only, and absence of beautiful things (OR, 2.23; 95% CI, 1.42-3.50) and high traffic making it unsafe to walk (OR, 2.39; 95% CI, 1.49-3.83) associated with overweight in women only. There were few significant interactions between environmental factors and neighborhood SES regarding overweight. Conclusion: Neighbourhood environment factors were associated with being overweight among Nigerian adults. These findings support previous reports in international literature, but should be replicated in other African studies before any firm conclusions can be drawn

Recently Evolved Francisella-Like Endosymbiont Outcompetes an Ancient and Evolutionarily Associated Coxiella-Like Endosymbiont In the Lone Star Tick (\u3ci\u3eAmblyomma americanum\u3c/i\u3e) Linked to the Alpha-Gal Syndrome

Background: Ticks are hematophagous arthropods that transmit various bacterial, viral, and protozoan pathogens of public health significance. The lone star tick (Amblyomma americanum) is an aggressive human-biting tick that transmits bacterial and viral pathogens, and its bites are suspected of eliciting the alpha-gal syndrome, a newly emerged delayed hypersensitivity following consumption of red meat in the United States. While ongoing studies have attempted to investigate the contribution of different tick-inherent factors to the induction of alpha-gal syndrome, an otherwise understudied aspect is the contribution of the tick microbiome and specifically obligate endosymbionts to the establishment of the alpha-gal syndrome in humans. Materials and Methods: Here we utilized a high-throughput metagenomic sequencing approach to cataloging the entire microbial communities residing within different developmental stages and tissues of unfed and blood-fed ticks from laboratory-maintained ticks and three new geographical locations in the United States. The Quantitative Insights Into Microbial Ecology (QIIME2) pipeline was used to perform data analysis and taxonomic classification. Moreover, using a SparCC (Sparse Correlations for Compositional data) network construction model, we investigated potential interactions between members of the microbial communities from laboratory-maintained and field-collected ticks. Results: Overall, Francisellaceae was the most dominant bacteria identified in the microbiome of both laboratory-raised and field-collected Am. americanum across all tissues and developmental stages. Likewise, microbial diversity was seen to be significantly higher in field-collected ticks compared with laboratory-maintained ticks as seen with a higher number of both Operational Taxonomic Units and measures of species richness. Several potential positive and negative correlations were identified from our network analysis. We observed a strong positive correlation between Francisellaceae, Rickettsiaceae, and Midichloriaceae in both developmental stages and tissues from laboratory-maintained ticks, whereas ovarian tissues had a strong positive correlation of bacteria in the family Xanthobacteraceae and Rhizobiaceae. A negative interaction was observed between Coxiellaceae and Francisellaceae in Illinois, and all the bacteria detected from ticks from Delaware were negatively correlated. Conclusion: This study is the first to catalog the microbiome of Am. americanum throughout its developmental stages and different tissue niches and report the potential replacement of Coxiellaceae by Francisellaceae across developmental stages and tissues tested except in ovarian tissues. These unique and significant findings advance our knowledge and open a new avenue of research to further understand the role of tick microbiome in tick-borne diseases and develop a holistic strategy to control alpha-gal syndrome