Influence of the layer thickness in plasmonic gold nanoparticles produced by thermal evaporation

Metallic nanoparticles (NPs) have received recently considerable interest of photonic and photovoltaic communities. In this work, we report the optoelectronic properties of gold NPs (Au-NPs) obtained by depositing very thin gold layers on glass substrates through thermal evaporation electron-beam assisted process. The effect of mass thickness of the layer was evaluated. The polycrystalline Au-NPs, with grain sizes of 14 and 19 nm tend to be elongated in one direction as the mass thickness increase. A 2 nm layer deposited at 250°C led to the formation of Au-NPs with 10-20 nm average size, obtained by SEM images, while for a 5 nm layer the wide size elongates from 25 to 150 nm with a mean at 75 nm. In the near infrared region was observed an absorption enhancement of amorphous silicon films deposited onto the Au-NPs layers with a corresponding increase in the PL peak for the same wavelength region.

A diversity profile from the staphylococcal community on atopic dermatitis skin: a molecular approach

AIMS

The aim of this study was to determine the biodiversity of the skin staphylococcal community from patients with atopic dermatitis (AD) and superantigen (SAg) detection from Staphylococcus aureus isolates.

METHODS AND RESULTS

In this study, we developed a novel multiplex PCR that allows the identification and discrimination of bacteria belonging to the Staphylococcus genus both Staph. aureus and coagulase-negative Staphylococcus - Staph. capitis, Staph. epidermidis, Staph. haemolyticus and Staph. hominis isolated from the skin of patients with AD. In addition, a multiplex PCR assay that allows the rapid screening of the 19 genes that encode staphylococcal enterotoxins (SEs), SE-like toxins and toxic shock syndrome toxin-1 was also performed and applied in Staph. aureus isolates. The microflora of the skin of patients with AD was dominated by Staph. aureus (69 isolates, 35·6%) followed by Staph. epidermidis (59 isolates, 30·4%) species. The SElM and SElN genes were the most frequently detected in our study (15 isolates, 71·4%), followed by SEG and SElO (14 isolates, 66·7%).

CONCLUSIONS

Our molecular-based approach successfully identified the staphylococcal microflora that was relatively specific to patients with AD. Considering skin colonization and expression of virulence factors, the Staph. aureus may play a relevant role in AD pathophysiology.

SIGNIFICANCE AND IMPACT OF THE STUDY

This ability to classify disease-related microbial species provides new insights into the relevance of those microbes in human disorders.

Zebrafish (Danio rerio) life-cycle exposure to chronic low doses of ethinylestradiol modulates p53 gene transcription within the gonads, but not NER pathways

Parental full life-cycle exposure to ethinylestradiol (EE₂) significantly affects embryo development and survival. One of the possible mechanisms of action of EE₂ may involve the impairment of an organism's ability to repair DNA damage. DNA repair mechanisms have sophistically evolved to overcome DNA damaging hazards that threaten the integrity of the genome. In the present study, changes in the transcription levels of key genes involved in two of the most thoroughly studied DNA repair systems in mammals were evaluated in adult zebrafish (Danio rerio) gonad upon full life-cycle exposure to chronic environmentally low levels of EE₂ (i.e., 0.5, 1 and 2 ng/L EE₂). Real time PCR was used to analyse the expression levels of nucleotide excision repair genes (NER) as well as the tumor suppressor p53 and downstream selected effectors, i.e., p21 (cyclin-dependent kinase inhibitor), GADD45α (growth arrest and DNA damage induced 45, alpha), bax (bcl2-associated X protein) and p53 key regulator MDM2 (murine double minute 2 protein). NER genes transcription levels in gonads did not differ significantly among treatments. In contrast, the number of transcripts of p53 gene was significantly increased in male gonads at all EE₂ exposure concentrations and in females at 1 ng/L EE₂. Despite the increase in p53 transcripts, transcription levels of p21, GADD45α and bax genes were not affected upon EE₂ treatment, whereas MDM2 gene expression significantly increased in females at the intermediate EE₂ dose (1 ng/L). Overall, the present study indicate that chronic low levels of EE₂ significantly modulates the transcription of p53, a key gene involved in DNA repair, particularly in male zebrafish gonads, which supports the hypothesis of an impact of EE2 in male gonad DNA repair pathways.

Gender differences in the risk of coronary artery disease in iran

BACKGROUND

Given gender differences in the risk of coronary artery disease (CAD), the present study sought to investigate these dissimilarities amongst patients who underwent angiography at a major, tertiary heart hospital in Iran.

METHODS

Between 2005 and 2010, 44,820 patients who underwent coronary angiography were enrolled in a registry. Pre-procedural data such as demographics, CAD risk factors, presenting symptoms, and laboratory tests, as well as post-procedural data were collected. The data were, subsequently, compared between the men and women.

RESULTS

Out of the 44,820 patients (16,378 women), who underwent coronary angiography, 37,358 patients (11,995 women) had CAD. Amongst the CAD patients, the females were not only significantly older, less educated, and more overweight than were the males but also had higher levels of triglyceride, cholesterol, low-density lipoprotein, high-density lipoprotein, and fasting blood sugar (P< 0.001). Of all the risk factors, hypertension and diabetes mellitus showed the strongest association in our female CAD patients (OR=3.45, 95%CI: 3.28-3.61 and OR=2.37, 95%CI: 2.26-2.48, respectively). Acute coronary syndrome was more prevalent in the men (76.1% vs. 68.6%, P< 0.001), and chronic stable angina was more frequent in the females (31.4% vs. 23.9%, P< 0.001). With respect to post-procedural recommendations, the frequency of recommendations for non-invasive modalities was higher in the females (20.1% vs. 18.6%, P< 0.001).

CONCLUSION

Hypertension and diabetes mellitus had the strongest association with CAD in our female patients. In the extensive CAD patients, medical treatment was recommended to the women more often.

Rapid-behaviour responses as a reliable indicator of estrogenic chemical toxicity in zebrafish juveniles

Whereas biochemical and molecular parameters have been well recognised as important "signposts" of individual disturbance to endocrine disrupting chemical's (EDCs) exposure, behavioural endpoints are yet greatly overlooked as a routine tool in environmental risk assessment of EDCs. However, life histories are intimately associated with numerous inter- and intra-specific interactions, which invariably depend on the performance of effective behaviours. Within fish species, one of the most important factors influencing energy turnover earlier in the development is locomotor activity. This essential trait reflects the organism's ability to generate and coordinate the metabolic energy required for both reproductive and non-reproductive behaviours. Inappropriate movement responses due to toxic effects of contaminants may ultimately impact important ecological variables. Therefore, in the present study, the swimming bursts of zebrafish juveniles exposed for 40 d to the synthetic estrogen ethinylestradiol (EE(2)), tested at environmentally relevant concentrations (nominal concentrations of 0.5, 1 and 2 ng L(-1)), were investigated in order to address the potential of rapid-behaviour patterns as an effective response indicator of estrogenic endocrine disrupting chemical's exposure. This synthetic estrogen was selected due to its high prevalence in aquatic ecosystems, ability to mimic natural estrogens and proven record of causing negative effects in fish reproduction. The behavioural responses were compared with established endpoints used in the screening of EE(2) effects at adulthood. Results indicate that zebrafish juveniles' swimming activity was significantly decreased upon EE(2) exposure. Since reduced locomotion of zebrafish may impact foraging, predator avoidance, drift and transport, and even interfere with social and reproductive behaviours, a fitness decline of wild fish populations can ultimately be hypothesized. Furthermore, behavioural endpoints were found to display higher sensitivity to EE(2) than either vitellogenin gene induction or reproductive parameters determined at adulthood. Overall, the findings of this work not only demonstrate the power of high-throughput behavioural responses, able to act as sensitive early warning signals of EDC exposure, but also highlight the potential of behavioural endpoints in providing a more comprehensive and non-invasive measure of EDC's exposure.

Disruption of zebrafish (Danio rerio) embryonic development after full life-cycle parental exposure to low levels of ethinylestradiol

Exposure of fish to the synthetic estrogen ethinylestradiol (EE2) has been shown to induce a large set of deleterious effects. In addition to the negative impact of EE2 in reproductive endpoints, concern has recently increased on the potential effects of EE2 in fish embryonic development. Therefore, the present study aimed at examining the effects of EE2 on the full embryonic development of zebrafish in order to identify the actual phases where EE2 disrupts this process. Hence, zebrafish were exposed to environmentally relevant low levels of EE2, 0.5, 1 and 2ng/L (actual concentrations of 0.19, 0.24 and 1ng/L, respectively) from egg up to eight months of age (F(1)), and the survival as well as the occurrence of abnormalities in their offsprings (F(2)), per stage of embryonic development, was investigated. A thorough evaluation of reproductive endpoints and transcription of vtg1 gene in the parental generation (F(1)) at adulthood, was performed. No significant differences could be observed for the two lowest EE2 treatments, in comparison with controls, whereas vtg1 transcripts were significantly elevated (40-fold) in the 2ng/L EE2 treatment. In contrast to the findings in the F(1) generation,a significant concentration-dependent increase in egg mortality between 8 and 24hours post-fertilization (hpf) was observed for all EE2 treatments, when compared with controls. The screening of egg and embryo development showed a significant increase in the percentage of abnormalities at 8 hpf for the highest EE2 concentration, a fact that might explain the increased embryo mortality at the 24 hpf time-point observation. Taken together, these findings indicate that the two lowest tested EE2 concentations impact late gastrulation and/or early organogenesis, whereas exposure to 2ng/L EE2 also disrupts development in the blastula phase. After early organogenesis has been completed (24 hpf), no further mortality was observed. These results show that increased embryo mortality occurs at EE2 levels below those inducing reproductive impairment and vtg1 gene induction in the male parental generation, thus suggesting that EE2 may impact some fish populations at levels below those inducing an increase in vtg1 transcripts. Hence, these findings have important implications for environmental risk assessment, strongly supporting the inclusion of embryonic development studies in the screening of endocrine disruption in wild fish populations.