Adolescent media use and its association to wellbeing in a Canadian national sample.

Our objective is to describe associations between media usage and multiple wellbeing indicators in a nationally representative sample of Canadian youth (CSTADS 2012-13) enrolled in grades 7 to 12 (N = 41,057). Youth reported media usage (television/movie viewing, videogame playing, and surfing the internet), wellbeing (academic achievement, school connectedness, self-esteem, physical activity, intake of fruits and vegetables, and bullying), and psychological (drug use, drinking, and smoking) and sociodemographic confounds (ethnicity, grade, province, gender). Videogame playing was negatively associated with academic achievement, b = -0.07 (99% CI, -0.08-05), physical activity, b = -3.09, (99% CI, -3.63-2.56), school connectedness, b = -0.03 (99% CI, -0.04-0.02), self-esteem, b = -0.13 (99% CI, -0.16-0.09), and the consumption of fruits and vegetables b = -0.07 (99% CI, -0.11-0.03). Internet usage was negatively related to self-esteem, b = -0.25 (99% CI, -0.28-0.21), school connectedness, b = -0.03 (99% CI, -0.03-0.02), academic achievement, b = -0.02 (99% CI, -0.03-0.002) and physical activity b = -1.42 (99% CI, -1.92-0.91). Finally, television exposure was linked with less fruits and vegetable consumption, b = -0.09 (99% CI, -0.12-0.06), academic achievement b = -0.05 (99% CI, -0.07-0.04), school connectedness b = -0.02 (99% CI, -0.03-0.01), self-esteem b = -0.06 (99% CI, -0.11-0.003), and physical activity b = -1.09 (99% CI, -1.64-0.54). Internet, television/movies, and videogame time also increased the odds of bullying others by 9%, OR = 1.09 (99% CI, 1.04-1.14) 8%, OR = 1.08 (99% CI, 1.01-1.16) and 7%, OR = 1.07 (99% CI, 1.01-1.14) respectively. Overall effect sizes were small yet may represent significant impairment for heavy media users.

Are Canadian youth still exposed to second-hand smoke in homes and in cars?

INTRODUCTION: The objective of this manuscript is to examine the prevalence of youth exposed to second-hand smoke (SHS) in homes and cars, changes in SHS exposure over time, and factors associated with beliefs youth hold regarding SHS exposure among a nationally representative sample of Canadian youth. METHODS: Descriptive analysis of SHS exposure in homes and cars was conducted using data from the Canadian Youth Smoking Survey (2004, 2006 and 2008). Logistic regression was conducted to examine factors associated with beliefs youth had about SHS exposure in 2008. RESULTS: In 2008, 21.5% of youth reported being exposed to SHS in their home on a daily or almost daily basis, while 27.3% reported being exposed to SHS while riding in a car at least once in the previous week. Between 2004 and 2008, the prevalence of daily SHS exposure in the home and cars decreased by 4.7% and 18.0% respectively. CONCLUSION: Despite reductions in SHS exposure over time, a substantial number of Canadian youth continue to be exposed to SHS in homes and cars. Further effort is required to implement and evaluate policies designed to protect youth from SHS.

TITRE: Les jeunes Canadiens sont-ils toujours exposés à la fumée secondaire à la maison et en voiture? INTRODUCTION: Nous étudions dans cet article la prévalence de l'exposition à la fumée secondaire (FS) chez les jeunes à la maison et en voiture, les variations du niveau d'exposition à la FS dans le temps et les facteurs associés aux croyances des jeunes au sujet de l'exposition à la FS, grâce à un échantillon représentatif à l'échelle nationale des jeunes Canadiens. MÉTHODOLOGIE: Nous avons mené une analyse descriptive de l'exposition à la FS à la maison et en voiture à l'aide des données de l'Enquête sur le tabagisme chez les jeunes (2004, 2006 et 2008). Une analyse de régression logistique a été effectuée afin d'analyser les facteurs associés aux croyances des jeunes au sujet de l'exposition à la FS en 2008. RÉSULTATS: En 2008, 21,5 % des jeunes ont signalé avoir été exposés à la FS à la maison chaque jour ou presque chaque jour, tandis que 27,3 % des jeunes ont déclaré avoir été exposés à la FS à bord d'une voiture au moins une fois au cours de la semaine précédente. Entre 2004 et 2008, la prévalence de l'exposition quotidienne à la FS au domicile et en voiture a diminué respectivement de 4,7 % et de 18,0 %. CONCLUSION: Malgré la diminution de l'exposition à la FS au fil du temps, un nombre important de jeunes Canadiens continuent à être exposés à la FS chez eux et en voiture. Il faut redoubler d'efforts pour mettre en oeuvre et évaluer des politiques visant à protéger les jeunes de la FS.

Research methods of the Youth Smoking Survey (YSS).

This paper describes the survey development, design and data collection protocol for the 2008/2009 Youth Smoking Survey (YSS) and the changes to the YSS survey and protocols across the 5 survey cycles (1994, 2002, 2004/2005, 2006/2007, 2008/2009). Canada's Youth Smoking Survey is a nationally representative school-based survey of students (grades 6 to 12 in 2008/2009) from randomly sampled public and private schools in the ten provinces. The main objective of the YSS is to provide benchmark data on national smoking prevalence rates for youth. Key features of the 2008/2009 YSS include consistent measures across survey cycles, a survey team of researchers and non-governmental organizations, a link to school and student level measures, provision of tailored feedback reports to schools and publicly available datasets.

Dynamical quark effects on light quark masses

Light quark masses are calculated in lattice QCD with two degenerate flavors of dynamical quarks. The calculations are made with improved actions with lattice spacing a = 0.22-0.11 fm. In the continuum limit we find m(M&Smacr;)(ud)(2 GeV) = 3.44(+0.14)(-0.22) MeV using the pi and rho meson masses as physical input, and m(M&Smacr;)(s)(2 GeV) = 88(+4)(-6) MeV or 90(+5)(-11) MeV with the K or straight phi meson mass as additional input. The quoted errors represent statistical and systematic combined, the latter including those from continuum and chiral extrapolations, and from renormalization factors. Compared to quenched results, two flavors of dynamical quarks reduce quark masses by about 25%.

Quenched light hadron spectrum

We present results of a large-scale simulation for the flavor nonsinglet light hadron spectrum in quenched lattice QCD with the Wilson quark action. Hadron masses are calculated at four values of lattice spacing in the range a approximately 0.1-0.05 fm on lattices with a physical extent of 3 fm at five quark masses corresponding to m(pi)/m(rho) approximately 0.75-0.4. The calculated spectrum in the continuum limit shows a systematic deviation from experiment, though the magnitude of deviation is contained within 11%. Results for decay constants and light quark masses are also reported.

Detection of Sphingomonas spp in soil by PCR and sphingolipid biomarker analysis.

Sphingomonas spp possess unique abilities to degrade refractory contaminants and are found ubiquitously in the environment. We developed Sphingomonas genus-specific PCR primers (SPf-190 and SPr1-852) which showed specific amplification of a 627-bp 16S rDNA fragment from Sphingomonas spp. A PCR assay using these Sphingomonas specific primers was developed to detect Sphingomonas aromaticivorans B0695R in three texturally distinct soil types, showing detection limits between 1.3-2.2 x 10(3) CFU g(-1) dry soil. A sphingolipid extraction protocol was also developed to monitor Sphingomonas populations in soil quantitatively. The detection limit of the assay was 20 pmol g(-1) dry soil, equivalent to about 3 x 10(5) cells g(-1) dry soil. Survival of S. aromaticivorans B0695R was monitored in the three different soils by antibiotic selective plate counting, PCR and sphingolipid analysis. All three approaches showed that the B0695R cells persisted in the low biomass Sequatchie sub-soil at about 3-5 x 10(7)cells g(-1) dry soil. In comparison to the plate counting assay, both the PCR and sphingolipid analysis detected a significantly higher level of B0695R cells in the clay soil and Sequatchie top-soil, indicating the possibility of the presence of viable but non-culturable B0695R cells in the soils. The combination of PCR and sphingolipid analysis may provide a more realistic estimation of Sphingomonas population in the environment.

The signature 10-hydroxy stearic acid thought to correlate with infectivity in oocysts of Cryptosporidium species is an artifact.

Heating or freezing leads to loss in infectivity of oocysts of Cryptosporidium parvum toward neonatal BALB/c mice and is reflected in the profile of the polar lipid fatty acids. Upon loss of infectivity, the ratio of polar lipid to neutral lipid fatty acid decreased and the relative proportions of 18:1n-9 also decreased; proportions of 18:2n-6 and 20:5n-6 increased, whereas the proportions of 16:0 remained constant with freezing. During these investigations, a novel fatty acid, 10-OH 18:0, was discovered in the glycolipid fraction. The identification of a fatty acid unique to species of Cryptosporidium was thought to provide a specific biomarker for this organism. Cryptosporidium also demonstrated fluctuations in absolute quantities of 10-OH 18:0 with events that lead to loss of infectivity. This led to the presumed correlation of this biomarker with infectious Cryptosporidium. The 10-OH 18:0 was putatively localized at the sn-2 position of phosphatidylethanolamine. High-performance liquid chromatography/electrospray ionization mass spectrometry revealed that the 10-OH 18:0 existed principally in the free fatty acid form. Herein, we establish that the free fatty acid 10-OH 18:0 was, in actuality, an artifact of the procedures for sample preparation.

Experimental and clinical results of fiberoptic argon laser stapedotomy.

Since 1992 a small air-cooled opthalmological argon laser (Argus system, 3 W max.) equipped with a fiberoptic microhandpiece has been used for stapedotomy at the Inselspital, Berne. The microhandpiece has been developed especially for otological purposes in our electronic laboratory. In order to measure the effect of argon laser pulses applied through the handpiece to the ear, we performed temperature measurements in a saline-filled inner ear model by using ultrathin (2 microns thick), ultrafast (4 ns) thermosensitive rhodamine-coated polyurethane films. Multiple laser pulses of 1-2.5 W and 0.1 s duration - as used in clinical applications - produced a temperature elevation of about 1 degree C in the liquid of the inner ear model. The local laser effect was then examined histologically on the isolated stapes. The thermal damage zone around the stapedotomy perforation was limited to about 100 microns. In a clinical study we compared the results of argon laser stapedotomy (n = 54) with those of a skeeter microdrill stapedotomy (n = 29). Substantial hearing gains were found in all cases in both groups. In the laser stapedotomy group the mean residual air-bone gap (0.5-2 kHz) was 10 dB or less in all cases but one. Inner ear function remained unchanged except for a 40-dB loss at 4000 Hz in one case. Transient vertigo with nystagmus occurred in one case. Facial nerve dysfunction did not occur in any patient. The most important advantage of the laser found was the absence of mechanical trauma to the stapes. Stapes luxation and a floating footplate were avoided. In contrast, thick footplates were more easily perforated with the skeeter. Use of an argon laser equipped with a fiberoptic microhandpiece and a skeeter microdrill as needed seems particularly advantageous for stapedotomy.

Resolution of the nirD locus for heme d1 synthesis of cytochrome cd1 (respiratory nitrite reductase) from Pseudomonas stutzeri.

The genetic organization of the nirD locus of Pseudomonas stutzeri ZoBell, necessary for a catalytically active cytochrome cd1 (EC 1.9.3.2), was determined. The locus comprises the unidirectionally transcribed open reading frames nirFDLGH, downstream of nirMC of the nir gene cluster, and immediately upstream of the norCB operon encoding nitric oxide (NO) reductase (EC 1.7.99.7). Notable sequence relatedness was found between NirF and cytochrome cd1 (NirS), within NirDLGH, and between NirM and NirC, suggesting several gene duplication events in this region. The derived NirF protein (391 amino acids, M(r) 43,137) has 23.8% identity (51.1% overall similarity) with NirS, but lacks the N-terminal heme-c-binding domain of NirS. Insertional mutagenesis of the five open reading frames resulted in the loss of respiratory nitrite reductase activity in vivo and in vitro. Mutant strains, when induced with nitrate for denitrification, synthesized a periplasmic cytochrome cd1 lacking heme d1. The defect was caused by the inability of the cell to synthesize heme d1. The nirD locus is proposed to encode a multimeric and multifunctional enzyme complex involved in the synthesis of heme d1. Mutations in nirFDLGH lowered substantially the expression level of norCB. Nir- mutants, unable to generate NO in vivo, provide indirect evidence for an NO sensor and an inducer role of NO for its cognate reductase.

Characterization of heme c peptides by mass spectrometry.

Liquid secondary ion mass spectrometry, also called fast atom bombardment mass spectrometry, has been used to determine proteolytic hydrolysis sites for peptides derived from c-type cytochromes that contain covalently attached heme c. An unexpected fragmentation occurs that breaks the covalent thioether bonds between the heme and the peptide, and the heme fragment further rearranges to give rise to an intense ion at m/z of 617 that corresponds to protonated iron protoporphyrin IX. The observation of this ion fragment can be used to unambiguously identify the presence of authentic heme c in peptides or peptide mixtures at the subnanomole level.

[Simulated epileptiform discharges during the replay of a lengthy EEG recording]. / Vorgetäuschte epileptische Anfallsentladungen bei Wiedergabe einer Langzeit-EEG-Aufzeichnung.

Reviewing a longterm-EEG magnet-recording on the video system of the play-back unit "Mobile Oxford Medilog 9000" EEG patterns appeared, which imposed as epileptiform discharges. They seemed to correlate with the paroxysmal clinical disturbances the patient had experienced and noted in a diary, and could be printed out on a normal EEG-apparatus. Following investigations demonstrated the artificial origin of this EEG patterns: They appeared in fact only using the switches of the play-back unit for the fast back- and forward winding. The time-correlation between clinical and electroencephalographic episodes was simulated by the search of selected EEG-sequences based on the clinical episodes noted from the patient.