Comparison of Langmuir probe and optical emission spectroscopy on a volume-cusp filament ion source using helium.

D-Pace has a Penning ion source that runs with helium for studies of α-particle production. We want to study its plasma properties as a function of varying operational parameters, which results in varied output ion beam characteristics. In order to diagnose the ion source plasma, a collisional-radiative code for helium to be used with optical emission spectroscopy measurements is developed. This has the advantage of being non-invasive, which allows for measurements using the emitted light from the plasma. This collisional-radiative code is shown to compare well with the Yacora on the Web model developed at IPP-Garching, and improves upon it with the addition of radiation trapping. Furthermore, the sensitivity of this model to the inclusion of additional excited state populations and non-Maxwellian electron energy distribution functions is investigated. It is shown that non-Maxwellian distributions can significantly affect spectroscopy measurements. This diagnostic is benchmarked to Langmuir probe measurements on the TRIUMF-licensed volume-cusp ion source to determine whether it can replicate the measured electron density and electron temperature as a function of varied operational parameters. The operational parameters are helium gas flow (10-40 SCCM), arc voltage (100-200 V), and arc current (1-5 A). The measured plasma properties, while different in absolute value, have similar trends for each operational parameter except when varying arc voltage. It is shown that this mismatch as a function of arc voltage is likely due to high energy non-Maxwellian electrons from the cathode sheath, which are not included within the collisional-radiative model.

ISIS Penning source extraction studies reveal the 3-dimensional Child-Langmuir effect.

The standard 1X ISIS negative Penning surface plasma source has reliably produced an H- beam for ISIS operations for 35 years. In order to meet the 60 mA, 2 ms, and 50 Hz beam current and duty cycle required for the front end test stand (Letchford et al., in Proceedings of IPAC2015, Richmond, VA, USA, 2015), a 2X scaled source has been developed [Faircloth et al., AIP Conf. Proc. 2052, 050004 (2018)]. The 2X source has a plasma chamber twice the linear dimensions of the 1X source. This paper investigates the comparison between different emission areas (plasma electrode aperture dimensions) for both the 1X and 2X sources. Slit and circular extraction schemes are studied. A 3D Child-Langmuir relationship is observed where the space charge limited current density depends on the aspect ratio of the extraction aperture.

Invasive group A streptococcal infection outbreaks of typeemm118 in a long-term care facility, and of type emm74 in the homeless population, Montréal, Quebec.

BACKGROUND: Two invasive group A streptococcus (iGAS) infection outbreaks occurred in Montreal in 2016 and 2017; one in a long-term care facility (typeemm118) and one in the community, primarily involving homeless people (typeemm74). OBJECTIVE: To describe two recent iGAS outbreaks in Montréal and highlight the challenges in dealing with these outbreaks and the need to tailor the public health response to control them. METHODOLOGY: All cases of iGAS were investigated and the isolates were sent to the laboratory foremmtyping. In both outbreaks, cases of superficial group Astreptococcus(GAS) infection were identified, through 1) systematic case detection accompanied by screening for asymptomatic carriers among residents and employees of the long-term care facility and 2) sentinel surveillance among homeless people. Visits were made to community organizations providing homeless services (including shelters) and social networks were analyzed to establish whether there were any links among cases of GAS infection (both invasive and noninvasive) and locations frequented. In both outbreaks, recommendations were made to service providers regarding enhancement of infection prevention and control measures. RESULTS: In the long-term care facility, five cases of typeemm118 iGAS were identified over a 22-month period, one of which resulted in death. All residents were screened and no carriers were identified. Among the employees, 81 (65%) were screened and fourcarriers were identified. Of those, one was a carrier of typeemm118 GAS. All carriers were treated, and subsequent follow-up sampling on three carriers (including the one withemm118) was negative.In the community, 23 cases of typeemm74 iGAS were detected over a 16-month period, four of which resulted in death. Half of the cases (n=12) were described as homeless, and six others were users of services for the homeless. Sentinel surveillance of superficial infections yielded 64 cultures with GAS, chiefly on the skin, including 51 (80%) of typeemm74. An analysis of the social networks revealed the large number and variety of resources for the homeless used by the cases. Visits to the community organizations providing homeless services revealed the heterogeneity and precariousness of some of these services, the difficulties encountered in applying adequate health and hygiene measures, and the high degree of mobility amongst those who use these services. CONCLUSION: The detection and control of iGAS outbreaks in both long-term care establishments and among community organizations providing homeless services are very complex. An outbreak of iGAS can develop in the background over a long time and be easily overlooked despite cases being admitted to the hospital.Emmtyping and systematic research of previous cases of iGAS are essential tools for the detection and characterization of outbreaks. Close cooperation among public health agencies, clinical teams, community organizations and laboratories is essential for proper monitoring and the reduction of GAS transmission in the community and health care settings.

Outbreak of tuberculosis among substance users and homeless people in Greater Montréal, Canada, 2003-2016.

BACKGROUND: In Canada, active tuberculosis (TB) is found mainly among migrants from endemic countries and Indigenous populations. However, cases of active tuberculosis in substance users and homeless persons have been reported in Greater Montréal since 2003. OBJECTIVE: To describe the Montréal TB outbreak in terms of the sociodemographic characteristics, risk factors and clinical characteristics of cases, as well as the intensity of public health interventions, the follow-up and identification of locations of potential transmission. METHODS: All cases of active tuberculosis with the same genotype of interest residing in Quebec and epidemiologically linked cases were included in the analysis. Data were retrospectively extracted from routine public health investigations. Characteristics of cases were summarized using Excel. Spatial analysis of locations frequented during cases' infectiousness periods was performed. RESULTS: Between January 2003 and February 2016 a total of 35 cases were identified. Most (86%) were non-Indigenous people born in Canada. Of these, 28 had several risk factors, including substance use (93%), alcohol abuse (64%), homelessness (46%), comorbidities such as HIV coinfection (36%) and advanced stage of the disease. Seven cases without risk factors were all close contacts of cases. Intensity of case management by public health authorities was high. Locations frequented by cases with risk factors included crack houses, shelters and rehabilitation centers in Montréal's downtown core and a residential setting in a suburban area. CONCLUSION: TB outbreaks can occur in marginalized Canadian-born urban populations, especially those with substance use. Tailored interventions in this population may be needed for screening, and earlier identification of both latent and active TB and better linkage to care.

Salmonella Thompson outbreak associated with consumption of chicken shawarma and the usefulness of genome sequencing in the investigation.

BACKGROUND: A sudden increase in Salmonella Thompson (S. Thompson) cases distributed throughout three border regions in the province of Quebec in November 2016 triggered a provincial investigation to identify a common source of contamination and to put the appropriate control measures into place. OBJECTIVE: To report on the outbreak and to describe the use of genomic sequencing to identify the salmonella serotype responsible. METHODS: A descriptive survey of all reported cases of Salmonella serogroup C1 that had occurred between October 1, 2016 and February 15, 2017 was conducted. A case definition was developed. Pulsed field gel electrophoresis supplemented by analyses of genome sequences using the single nucleotide variant phylogenomics method were used to demarcate and manage the outbreak. RESULTS: Eighteen cases of S. Thompson were identified through whole genome sequencing. The onset dates of symptoms for the 16 cases that presented enteric symptoms were November 21-December 2, 2016. Two cases that presented with atypical symptoms were not reported until February 2017. Among the 18 cases, 16 had eaten or probably eaten chicken shawarma at the same restaurant chain and nine of these cases ate it at the same restaurant. In total, five restaurants from this chain, spread throughout three border regions of Quebec, were identified. CONCLUSION: Outbreaks associated with chicken shawarma have been identified in the past. Efforts must be made to ensure that the owners of this type of restaurant know the contamination risk associated with this type of cooking and take the necessary steps to reduce this risk. The use of the genome sequencing method was very useful in defining the outbreak.

Association between prenatal care and small for gestational age birth: an ecological study in Quebec, Canada. / Lien entre les soins prénataux et le faible poids pour l'âge gestationnel à la naissance : une étude écologique au Québec (Canada).

BACKGROUND: In Quebec, women living on low income receive a number of additional prenatal care visits, determined by their area of residence, of both multi-component and food supplementation programs. We investigated whether increasing the number of visits reduces the odds of the main outcome of small for gestational age (SGA) birth (weight < 10th percentile on the Canadian scale). METHODS: In this ecological study, births were identified from Quebec's registry of demographic events between 2006 and 2008 (n = 156 404; 134 areas). Individual characteristics were extracted from the registry, and portraits of the general population were deduced from data on multi-component and food supplement interventions, the Canadian census and the Canadian Community Health Survey. Mothers without a high school diploma were eligible for the programs. Multilevel logistic regression models were fitted using generalized estimating equations to account for the correlation between individuals on the same territory. Potential confounders included sedentary behaviour and cigarette smoking. The odds ratios (ORs) were adjusted for mother's age, marital status, parity, program coverage and mean income in the area. RESULTS: Mothers eligible for the programs remain at a higher odds of SGA than non-eligible mothers (OR = 1.40; 95% confidence interval [CI]: 1.30-1.51). Further, areas that provide more visits to eligible mothers (4-6 food supplementation visits) seem more successful at reducing the frequency of SGA birth than those that provide 1-2 or 3 visits (OR = 0.86; 95% CI: 0.75-0.99). CONCLUSION: Further studies that validate whether an increase in the number of prenatal care interventions reduces the odds of SGA birth in different populations and evaluate other potential benefits for the children should be done.

INTRODUCTION: Au Québec, les femmes vivant avec un faible revenu reçoivent un certain nombre de visites de soins prénataux supplémentaires, en fonction de leur lieu de résidence, dans le cadre d'un programme à multiples composantes et d'un programme d'intervention comprenant des suppléments alimentaires. Nous avons examiné si l'augmentation du nombre de visites réduisait le risque de faible poids pour l'âge gestationnel à la naissance (poids inférieur au 10e percentile sur l'échelle canadienne). MÉTHODOLOGIE: Pour cette étude écologique, nous avons sélectionné les naissances dans le registre des événements démographiques du Québec entre 2006 et 2008 (n = 156 404; 134 secteurs). Les caractéristiques individuelles ont été extraites du registre des naissances alors que les portraits de la population générale ont été déduits de données sur l'intervention à multiples composantes et du programme d'intervention comprenant des suppléments alimentaires, ainsi que des recensements canadiens et des Enquêtes sur la santé dans les collectivités canadiennes. Ont été considérées comme admissibles aux programmes les mères sans diplôme d'études secondaires. Les modèles de régression logistique multiniveaux ont été ajustés à l'aide d'équations d'estimation généralisées pour tenir compte de la corrélation entre les individus vivant sur un même territoire. Les principaux facteurs confusionnels potentiels étaient la sédentarité et le tabagisme. Les rapports de cotes (RC) ont été ajustés en fonction de l'âge, de l'état matrimonial et de la parité de la mère ainsi que de la couverture du programme et du revenu moyen dans le secteur. RÉSULTATS: Les mères admissibles aux programmes se sont révélées plus à risque de donner naissance à un bébé de faible poids pour l'âge gestationnel à la naissance que les autres mères (RC = 1,40; intervalle de confiance [IC] à 95 % : 1,30 à 1,51). De plus, les secteurs offrant un plus grand nombre de visites aux mères admissibles (4 à 6 visites dans le cadre du programme d'intervention comprenant des suppléments alimentaires) semblent mieux réussir à réduire la fréquence du faible poids pour l'âge gestationnel à la naissance que ceux offrant soit 1 ou 2 visites, soit 3 visites (RC = 0,86; IC à 95 % : 0,75 à 0,99). CONCLUSION: Il est nécessaire de conduire des études supplémentaires pour valider qu'une augmentation du nombre d'interventions en soins prénataux réduit le risque de faible poids pour l'âge gestationnel à la naissance au sein de différentes populations et pour en évaluer d'autres avantages potentiels pour les enfants.

Impact of individual and ecological characteristics on small for gestational age births: an observational study in Quebec.

INTRODUCTION: We evaluated associations between ecological variables and the risk of very small for gestational age (VSGA) birth in Quebec in 2000-2008. METHODS: Ecological variables came from the Canadian Community Health Survey, the Canadian census and Quebec's birth registry; individual variables also came from Quebec's birth registry. Odds ratios (ORs) adjusted for mother's age, academic qualification, parity, marital status and country of birth were estimated using multilevel logistic regression (generalized estimating equations method). RESULTS: Births in neighbourhoods with a high proportion of people leading a sedentary lifestyle (OR: 1.07, 95% confidence interval [CI]: 1.01-1.11) and those with a high/middle proportion of residents with food insecurity (OR: 1.09, 95% CI: 1.05-1.15; OR: 1.05, 95% CI: 1.01-1.11) had higher odds of VSGA birth. Those with middle proportion of married residents had lower odds of VSGA birth (OR: 0.94, 95% CI: 0.90-0.98).

TITRE: Incidence des caractéristiques individuelles et des caractéristiques du contexte sur les nouveau-nés de faible poids : une étude d'observation au Québec. INTRODUCTION: Nous avons analysé les liens entre certaines variables contextuelles, certaines caractéristiques des mères et le risque de donner naissance à des nouveau-nés très petits pour l'âge gestationnel (TPAG) au Québec entre 2000 et 2008. MÉTHODOLOGIE: Les variables liées au contexte ont été tirées de l'Enquête sur la santé dans les collectivités canadiennes, du Recensement canadien et du Registre des naissances du Québec. Les variables individuelles provenaient aussi du Registre des naissances du Québec. Les rapports de cotes (RC), ajustés selon l'âge de la mère, la scolarité, la parité, l'état matrimonial et le pays de naissance, ont été évalués au moyen de modèles de régression logistique multiniveau (par des équations d'estimation généralisées). RÉSULTATS: Les naissances survenues dans les quartiers présentant une proportion élevée de résidents sédentaires (RC : 1,07, intervalle de confiance [IC] à 95% : 1,01 à 1,11) et dans les quartiers présentant une proportion moyenne (RC : 1,09, IC à 95% : 1,05 à 1,15) ou élevée de résidents souffrant d'insécurité alimentaire (RC : 1,05, IC à 95% : 1,01 à 1,11) présentaient un risque accru d'être TPAG. Le risque de naissance de nouveau-né TPAG était plus faible dans les quartiers présentant une proportion moyenne de résidents mariés (RC : 0,94, IC à 95 % : 0,90 à 0,98).

Promoter suppression in cultured mammalian cells can be blocked by the chicken beta-globin chromatin insulator 5'HS4 and matrix/scaffold attachment regions.

Studies have indicated that two transcriptionally active units can repress one another when they lie adjacent in head-to-tail tandem on a chromosome. Repression of a downstream (3') unit by an upstream (5') unit is known as "transcriptional interference", whereas repression of a 5' unit by a 3' unit is termed "promoter suppression". These two processes can occur between head-to-tail tandem copies of a transgene, or between transgenes and adjacent chromosomal genes. Interference can be blocked by inserting a transcription terminator between adjacent units. Here, we report that "promoter suppression" could be blocked by the insulator 5' DNaseI hypersensitive site 4, or matrix/scaffold attachment regions (MAR/SARs), when these elements were interposed between adjacent units. Because intergenic spacers of many repeated eukaryotic genes contain MAR/SARs and insulators, our observations suggest that these elements have the ability to segregate repeated genes into domains that act independently of one another. Our observations also suggest strategies to design transgenes that can act as autonomous units of expression.

Defective herpes simplex virus type 1 vectors harboring gag, pol, and env genes can be used to rescue defective retrovirus vectors.

A retroviral packaging transcription unit was constructed in which the Moloney murine leukemia virus (MoMLV) gag-pol and env genes are expressed under the control of herpesvirus regulatory sequences. This transcription unit, lacking long terminal repeats, primer binding sites, and most of the retrovirus packaging signal but retaining both retroviral donor and acceptor splice sites, was cloned into a herpes simplex virus type 1 (HSV-1) amplicon plasmid, and amplicon vectors (the gag-pol-env [GPE] vectors) were generated by using a defective HSV-1 vector as helper virus. The GPE vector population was used to infect human TE671 cells (ATCC CRL 8805), harboring a lacZ provirus (TE-lac2 cells), and supernatants of infected cells were collected and filtered at different times after infection. These supernatants were found to contain infectious ecotropic lacZ retroviral particles, as shown both by reverse transcription-PCR and by their ability to transduce a beta-galactosidase activity to murine NIH 3T3 cells but not to human TE671 cells. The titer of retroviral vectors released by GPE vector-infected TE-lac2 cells increased with the dose of infectious amplicon particles. Retrovirus vector production was inhibited by superinfection with helper virus, indicating that helper virus coinfection negatively interfered with retrovirus production. Induction of retrovirus vectors by GPE vectors was neutralized by anti-HSV-1 but not by anti-MoMLV antiserum, while transduction of beta-galactosidase activity to NIH 3T3 cells by supernatants of GPE vector-infected TE-lac2 cells was neutralized by anti-MoMLV antiserum. These results demonstrate that HSV-1 GPE amplicon vectors can rescue defective lacZ retrovirus vectors and suggest that they could be used as a sort of launching ramp to fire defective retrovirus vectors from within virtually any in vitro or in vivo cell type containing defective retroviral vectors.

[The life experiences and the implication of caregivers in persons living with HIV]. / Le vécu et l'implication d'aidants naturels de personnes vivant avec le VIH.

This article focuses on a qualitative study, conducted in Montréal between March and July of 1990, whose aim was to understand the life experiences and the needs of close and supportive individuals that care for seropositive persons. The objective of the study is to help provide more direction to the scope of services dispensed by the Centre Pierre-Hénault, an organization created by a group of close supporters of HIV-infected persons. Eighteen individuals volunteered for the in-depth interviews: nine of these were caring for persons who had developed AIDS, four were providing support for persons who were HIV-positive, and the remaining five had assisted persons who passed away following AIDS-related diseases. The study shows that the risk of isolation is greater among those close supporters who provide care for HIV-positive persons. Although research does point to a number of fundamental traits that are shared among all types of supportive individuals, certain traits are specifically related to people caring for HIV-positive persons, including the taboo and the stigma that are linked to AIDS, as well as the rapid and unforeseen loss of people in their prime.

[Caregivers and HIV]. / Les aidants naturels et le VIH.

An exploratory study conducted among 18 natural caregivers of persons with HIV revealed that extreme emotion was the results of the high cost of personal devotion.