The room temperature phosphine-free synthesis of near-infrared emitting HgSe quantum dots

Luminescent mercury selenide (HgSe) quantum dots have been synthesised by a phosphine-free method using oleic acid as a capping agent. The modification of experimental conditions such as temperature resulted in particles of various sizes (15–100 nm) and morphologies not previously seen in HgSe, with emission tuneable between 1000 nm and 1350 nm

Making too much of a weak case

LetterB E Christopher Nordin, Robin M Daly, John Horowitz, Andrew V Metcalf

The Alkaloids of Ophiorrhiza communis and O. tomentosa

Two alkaloids, harman and strictosidinic acid, were isolated from the leaves and bark of Dphiorrhiza communis Linn. Strictosidinic acid was also isolated from Dphiorrhiza tomentosa Jack. These structural assignments were based on their physical and spectroscopic data

Type Ia supernova Hubble diagram with near-infrared and optical observations

We main goal of this paper is to test whether the NIR peak magnitudes of SNe Ia could be accurately estimated with only a single observation obtained close to maximum light, provided the time of B band maximum and the optical stretch parameter are known. We obtained multi-epoch UBVRI and single-epoch J and H photometric observations of 16 SNe Ia in the redshift range z=0.037-0.183, doubling the leverage of the current SN Ia NIR Hubble diagram and the number of SNe beyond redshift 0.04. This sample was analyzed together with 102 NIR and 458 optical light curves (LCs) of normal SNe Ia from the literature. The analysis of 45 well-sampled NIR LCs shows that a single template accurately describes them if its time axis is stretched with the optical stretch parameter. This allows us to estimate the NIR peak magnitudes even with one observation obtained within 10 days from B-band maximum. We find that the NIR Hubble residuals show weak correlation with DM_15 and E(B-V), and for the first time we report a possible dependence on the J_max-H_max color. The intrinsic NIR luminosity scatter of SNe Ia is estimated to be around 0.10 mag, which is smaller than what can be derived for a similarly heterogeneous sample at optical wavelengths. In conclusion, we find that SNe Ia are at least as good standard candles in the NIR as in the optical. We showed that it is feasible to extended the NIR SN Ia Hubble diagram to z=0.2 with very modest sampling of the NIR LCs, if complemented by well-sampled optical LCs. Our results suggest that the most efficient way to extend the NIR Hubble diagram to high redshift would be to obtain a single observation close to the NIR maximum. (abridged)Comment: 39 pages, 15 figures, accepted by A&

Selective amplification of bacterial 16S rDNA sequence from clinical samples

Background: Conventional blood culture method is time consuming and less sensitive; when fastidious or un-culturalable organisms are involved. The use of PCR targeting the 16S rRNA allows detection of bacteria; however, these primers have ability to co-amplify human DNA. This Polymerase Chain Reaction (PCR) method is based on nucleic acid amplification test. Objective of the study: This study determined a method for selective amplification of bacterial DNA from clinical samples without co-amplification of human DNA. Materials and methods: Seventy one blood samples from clinically suspected cases of early onset neonatal sepsis were collected and analysed in parallel by culture and 16S rRNA amplification. DNA was extracted using commercial extraction QiAmp mini DNA kit and subjected to 16S rRNA amplification. The products were sequenced, analysed and compared with blood culture results. Positive and negative controls were used for extraction and amplification respectively. Results: Out of 71 samples analysed, 5 (7.0%) samples by blood culture were equally positive for 16S rRNA PCR; the PCR was also able to identified 16 (22.5%) more positive samples which blood culture could not identify, but only 1 (1.4%) sample was identified positive using blood culture while PCR identified it as negative. During the study, 7 (9.9%) samples were identified positive by conventional blood culture but later found to be contaminants. Conclusion: This study confirmed the presence of 16S rRNA among bacterial isolates and modification of PCR protocol with shorter denaturation temperature and time, leading to selective amplification of bacterial DNA. Therefore, there is need to carry-out this investigation on both culturable and unculturable specimens. Keywords:16SrRNA amplification; bacterial DNA; human DNA and Polymerase chai

A prospective cohort study comparing the reactogenicity of trivalent influenza vaccine in pregnant and non-pregnant women

Background: Influenza vaccination during pregnancy can prevent serious illness in expectant mothers and provide protection to newborns; however, historically uptake has been limited due to a number of factors, including safety concerns. Symptomatic complaints are common during pregnancy and may be mistakenly associated with reactions to trivalent influenza vaccine (TIV). To investigate this, we compared post-vaccination events self-reported by pregnant women to events reported by non-pregnant women receiving TIV. Methods: A prospective cohort of 1,086 pregnant women and 314 non-pregnant female healthcare workers (HCWs) who received TIV between March-May 2014 were followed-up seven days post-vaccination to assess local and systemic adverse events following immunisation (AEFIs). Women were surveyed by text message regarding perceived reactions to TIV. Those reporting an AEFI completed an interview by telephone or mobile phone to ascertain details. Logistic regression models adjusting for age and residence were used to compare reactions reported by pregnant women and non-pregnant HCWs. Results: Similar proportions of pregnant women and non-pregnant, female HCWs reported ≥1 reaction following vaccination with TIV (13.0% and 17.3%, respectively; OR = 1.2 [95% CI: 0.8-1.8]). Non-pregnant, female HCWs were more likely to report fever or headache compared to pregnant women (OR: 4.6 [95% CI 2.1-10.3] and OR: 2.2 [95% CI 1.0-4.6], respectively). No other significant differences in reported symptoms were observed. No serious vaccine-associated adverse events were reported, and less than 2% of each group sought medical advice for a reaction. Conclusions: We found no evidence suggesting pregnant women are more likely to report adverse events following influenza vaccination when compared to non-pregnant female HCWs of similar age, and in some cases, pregnant women reported significantly fewer adverse events. These results further support the safety of TIV administered in pregnant women