Influence of swift heavy ion irradiation on the photoluminescence of Si-nanoparticles and defects in SiO2.

The influence of swift heavy ion (SHI) irradiation on the photoluminescence (PL) of silicon nanoparticles (SiNPs) and defects in SiO2-film is investigated. SiNPs were formed by implantation of 70 keV Si+ and subsequent thermal annealing to produce optically active SiNPs and to remove implantation-induced defects. Seven different ion species with energy between 3-36 MeV and fluence from 1011-1014 cm-2 were employed for irradiation of the implanted samples prior to the thermal annealing. Induced changes in defect and SiNP PL were characterized and correlated with the specific energy loss of the employed SHIs. We find that SHI irradiation, performed before the thermal annealing process, affects both defect and SiNP PL. The change of defect and SiNP PL due to SHI irradiation is found to show a threshold-like behaviour with respect to the electronic stopping power, where a decrease in defect PL and an anticorrelated increase in SiNP PL after the subsequent thermal annealing are observed for electronic stopping exceeding 3-5 keV nm-1. PL intensities are also compared as a function of total energy deposition and nuclear energy loss. The observed effects can be explained by ion track formation as well as a different type of annealing mechanisms active for SHI irradiation compared to the thermal annealing.

Stroke asymmetry of tilted superhydrophobic ion track textures.

The stroke asymmetry of contact angles of water drops on tilted hydrophobic textures is demonstrated, obtained by ion track etching followed by a hydrophobic treatment. Preliminary trends concerning the advancing and receding contact angles are established, each with and against stroke direction. In rough agreement with Cassie-Baxter theory, the cosines of these four contact angles depend linearly on the wetted area fraction. The etched tracks are randomly distributed on the surface of polycarbonate disks and inclined by 30 degrees with respect to the surface, whereby the aspect ratio of individual etched cones is larger than 10. The morphology of the resulting surface is characterized by randomly shaped flat tops overhanging on one side and gradually falling off on the other side. The area fraction of the supporting tops can be calculated from the number of impinging ions per unit area and the cross section of the etched ion tracks. The top layer of the texture consists of flat, horizontal, irregularly shaped tops supporting water drops in the Cassie-Baxter state. With increasing etching time, the texture becomes increasingly clefted. To fabricate the textures, we irradiated polycarbonate with 5 x 10(7) (80)Br(7+) ions/cm(2) of 30 MeV total energy (having a range of about 20 microm in polycarbonate) at a tilt angle of 30 degrees with respect to the sample surface and etched the latent ion tracks selectively. The textured surface is made hydrophobic by carbondifluoride radicals (CF(2)) resulting from the decay of octafluorocyclobutane, C(4)F(8), in a plasma reactor. The goal of the report is to show that the tilt orientation of a superhydrophobic surface leads to advancing and receding contact angles depending on the orientation with and against the stroke direction. In addition, a rotating movement is demonstrated qualitatively by floating a rotationally asymmetric disk on an ultrasonic bath, similarly treated after an irradiation with (1.2 +/- 0.4) x 10(7) (129)Xe(27+) ions/cm(2) of 8.3 MeV/nucleon at an angle of 45 degrees, whereby the superhydrophobic side of the disk points downward to the water of the ultrasonic bath.

Bacterial vaginosis--a laboratory and clinical diagnostics enigma.

Diagnosing bacterial vaginosis (BV) has long been based on the clinical criteria of Amsel et al., whereby three of four defined criteria must be satisfied. Though there are other criteria and scoring methods which function well in comparison (i.e. Nugent scoring), it is not certain that they will always identify the same category of patients. Point-of-care methods based on various combinations of microbial products, presence of RNA, or more complex laboratory instrumentations such as sensor arrays, have also been introduced for the diagnosis of BV. No method for diagnosing BV can at present be regarded as the best. It could be that--based partly on tacit knowledge on the part of the clinical investigators scoring in the clinic--various scoring systems have been chosen to fit a particular BV-related problem in a particular population. In this review we critically examine these pertinent issues influencing clinical scoring and laboratory diagnostics of BV.

Trimethylamine content in vaginal secretion and its relation to bacterial vaginosis.

The presence of a fishy odor emanating from women who present with a malodorous vaginal discharge is well known. The odor is due to bacterial reduction of trimethylamine oxide to trimethylamine (TMA) in vaginal secretion. The release of TMA from specimens of vaginal fluid following the addition of alkali is often used in making a clinical diagnosis of bacterial vaginosis (BV). We now report a sensitive gas chromatographic method for analysis and quantification of TMA in vaginal fluid in which weighed samples were used. In addition, a proper diagnosis of BV was obtained using Gram-stained smears of the vaginal fluid according to the method of Nugent et al. (R. P. Nugent et al., J Clin Microbiol 1991;29:297-301). We also diagnosed BV according to Hallén et al. (A. Hallén et al. Genitourin Med 1987;63:386-9). TMA was present in all women with a Nugent score between 7 and 10 and in almost all women diagnosed with BV according to the method of Hallén et al. TMA was not found or was only found in very low concentrations in vaginal fluid from women with Nugent scores of 0 to 3. TMA was also found in four women with a negative sniff test. It seems that high levels of TMA in samples of vaginal fluid are typical for BV regardless of the scoring method used for diagnosis. However, low levels of TMA, <5 microg/g vaginal fluid, do not always correlate with BV.

[Incontinentia pigmenti. A rare disease with many symptoms]. / Incontinentia pigmenti. En ovanlig sjukdom med många symtom.

Incontinentia pigmenti, also known as Bloch-Sulzberger syndrome, is a rare multi-systemic disorder. The disease is characterised by abnormalities in ectodermal tissues including the skin, eyes, central nervous system and dentition. It is inherited as an X-linked dominant trait and is usually fatal for male fetuses. Thirty-eight Swedish patients from 16 families were identified. Thirty patients were examined clinically and their DNA were analysed for deletions in the NEMO-gene. The disease showed a large clinical variability even within families and the common deletion in the NEMO-gene was found present in 70% of the families.

Composition of the vaginal microbiota in women of reproductive age--sensitive and specific molecular diagnosis of bacterial vaginosis is possible?

BACKGROUND AND OBJECTIVE: Bacterial vaginosis (BV) is the most common vaginal disorder, characterized by depletion of the normal lactobacillus-dominant microbiota and overgrowth of commensal anaerobic bacteria. This study aimed to investigate the composition of the vaginal microbiota in women of reproductive age (healthy women and women with BV), with the view of developing molecular criteria for BV diagnosis. MATERIALS AND METHODS: Vaginal samples from 163 women (79 control, 73 BV and 11 intermediate (Lactobacillary grade II flora) cases) were analyzed using 454 pyrosequencing of the hypervariable regions V3-V4 of the 16S rRNA gene and 16 quantitative bacterial species/genus-specific real-time PCR assays. Sensitivities and specificities of potential BV markers were computed using the Amsel criteria as reference standard for BV. The use of quantitative thresholds for prediction of BV, determined for both relative abundance measured with 454 pyrosequencing and bacterial load measured with qPCR, was evaluated. RESULTS: Relative to the healthy women, the BV patients had in their vaginal microbiota significantly higher prevalence, loads and relative abundances of the majority of BV associated bacteria. However, only Gardnerella vaginalis, Atopobium vaginae, Eggerthella, Prevotella, BVAB2 and Megasphaera type 1 detected at or above optimal thresholds were highly predictable for BV, with the best diagnostic accuracy shown for A. vaginae. The depletion of Lactobacillus species combined with the presence of either G. vaginalis or A. vaginae at diagnostic levels was a highly accurate BV predictor. CONCLUSIONS: Quantitative determination of the presence of G. vaginalis, A. vaginae, Eggerthella, Prevotella, BVAB2 and Megasphaera type 1 as well as the depletion of Lactobacillus was highly accurate for BV diagnosis. Measurements of abundance of normal and BV microbiota relative to total bacteria in vaginal fluid may provide more accurate BV diagnosis, and be used for test-of-cure, rather than qualitative detection or absolute counts of BV related microorganisms.

Effect of photonic bandgap on luminescence from silicon nanocrystals.

The modification of the luminescence of silicon nanocrystals experiencing the effect of a photonic bandgap in a 2D photonic crystal was investigated. The time-integrated photoluminescence spectra detected in the plane of the photonic crystal revealed a dip in the light emission corresponding to the wavelength of the bandgap, whose position changes according to the geometry of the prepatterned pillar array. The calculated emission pattern for a pointlike dipole placed in such a structure suggests an inhibition of the spontaneous emission rate at certain directions as a physical reason for the observed modification of luminescence.

Laboratory diagnosis of sexually transmitted infections in estonia in 2001-2002: shortcomings with impact on diagnostic quality and surveillance.

OBJECTIVES: The objectives of this study were to comprehensively characterize the range, content, and performance of sexually transmitted infection (STI) testing services in Estonia during the period 2001 to 2002 and to determine if the observed diagnostic laboratory practices and methods adhered to international evidence-based recommendations. STUDY: Survey data, focusing on organization and performance characteristics of STI diagnostics services, were assessed using questionnaires, telephone interviews, and site visits to all responding facilities providing STI diagnostics services in Estonia. Guidelines of international evidence-based recommendations for STI testing were used as references. RESULTS: There were significant shortcomings in STI testing availability and practices. Among all participating laboratories diagnosing STIs, only a minority (n = 16, 28%) offered testing for the full minimum range of relevant STIs in Estonia, i.e., Treponema pallidum, Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis. In addition, because testing methods used were not properly selected, confirmation of several infections in accordance with evidence-based requirements was not possible, which has an impact both on STI diagnostic quality and surveillance.