Project description:Despite considerable progress in the multifaceted chemistry of non-redox-metal alkylperoxides, the knowledge about magnesium alkylperoxides is in its infancy and only started to gain momentum. Harnessing the well-defined dimeric magnesium tert-butylperoxide [(f5BDI)Mg(μ-η2:η1-OOtBu)]2 incorporating a fluorinated β-diketiminate ligand, herein, we demonstrate its transformation at ambient temperature to a spiro-type, tetranuclear magnesium alkylperoxide [(f5BDI)2Mg4(μ-OOtBu)6]. The latter compound was characterized by single-crystal X-ray diffraction and its molecular structure can formally be considered as a homoleptic magnesium tert-butylperoxide [Mg(µ-OOtBu)2]2 terminated by two monomeric magnesium tert-butylperoxides. The formation of the tetranuclear magnesium alkylperoxide not only contradicts the notion of the high instability of magnesium alkylperoxides, but also highlights that there is much to be clarified with respect to the solution behaviour of these species. Finally, we probed the reactivity of the dimeric alkylperoxide in model oxygen transfer reactions like the commonly invoked metathesis reaction with the parent alkylmagnesium and the catalytic epoxidation of trans-chalcone with tert-butylhydroperoxide as an oxidant. The results showed that the investigated system is among the most active known catalysts for the epoxidation of enones.
Project description:Human leukocyte antigen (HLA) immune genes play an important role in partner selection, but it has remained unclear if nonrandom pairing with respect to parental HLA genes could occur at the level of the gametes. We tested this possibility by investigating whether the sperm fertilization competence in humans is dependent on HLA genotype combination of the partners. We conducted a full-factorial experiment, in which the sperm physiological preparation for fertilization among multiple males was studied in the presence of follicular fluid (oocyte surrounding bioactive liquid) of several females. All the studied sperm pre-fertilization physiological parameters (motility, hyperactivation, acrosome reaction, and viability) were strongly dependent on male-female combination. In other words, follicular fluids (women) that induce strong sperm physiological response in some males often induce much weaker response in the other(s). Sperm physiological responses were stronger in HLA-dissimilar male-female pairs than in HLA-similar combinations, but none of the measured sperm traits were associated with genome-wide similarity. Together, these findings shed new light on the evolutionary and immunological mechanisms of fertilization. Furthermore, our results raise an intriguing possibility that against currently prevailing WHO's definition, infertility may not represent exclusively a pathological condition, but may also result from immunogenetic incompatibility of the gametes.
Project description:This work is focused on the fabrication and analysis of graphene-based, solution-gated field effect transistor arrays (GFETs) on a large scale for bioelectronic measurements. The GFETs fabricated on different substrates, with a variety of gate geometries (width/length) of the graphene channel, reveal a linear relation between the transconductance and the width/length ratio. The area normalised electrolyte-gated transconductance is in the range of 1-2 mS·V-1·□ and does not strongly depend on the substrate. Influence of the ionic strength on the transistor performance is also investigated. Double contacts are found to decrease the effective resistance and the transfer length, but do not improve the transconductance. An electrochemical annealing/cleaning effect is investigated and proposed to originate from the out-of-plane gate leakage current. The devices are used as a proof-of-concept for bioelectronic sensors, recording external potentials from both: ex vivo heart tissue and in vitro cardiomyocyte-like HL-1 cells. The recordings show distinguishable action potentials with a signal to noise ratio over 14 from ex vivo tissue and over 6 from the cardiac-like cell line in vitro. Furthermore, in vitro neuronal signals are recorded by the graphene transistors with distinguishable bursting for the first time.
Project description:BackgroundVaccine hesitancy is one of the contributors to low vaccination coverage in both developed and developing countries. Sudan is one of the countries that suffers from low measles vaccine coverage and from measles outbreaks. In order to facilitate the future development of interventions, this study aimed at exploring the opinions of Expanded Program on Immunization officers at ministries of health, WHO, UNICEF and vaccine care providers at Khartoum-based primary healthcare centers.MethodsQualitative data were collected using semi-structured interviews during the period January-March 2018. Data (i.e. quotes) were matched to the categories and the sub-categories of a framework that was developed by the WHO-SAGE Working Group called ''Determinants of Vaccine Hesitancy Matrix''.FindingsThe interviews were conducted with 14 participants. The majority of participants confirmed the existence of measles vaccine hesitancy in Khartoum state. They further identified various determinants that were grouped into three domains including contextual, groups and vaccination influences. The main contextual determinant as reported is the presence of people who can be qualified as "anti-vaccination". They mostly belong to particular religious and ethnic groups. Parents' beliefs about prevention and treatment from measles are the main determinants of the group influences. Attitude of the vaccine providers, measles vaccine schedule and its mode of delivery were the main vaccine related determinants.ConclusionMeasles vaccine hesitancy in Sudan appears complex and highly specific to local circumstances. To better understand the magnitude and the context-specific causes of measles vaccine hesitancy and to develop adapted strategies to address them, there is clearly a further need to investigate measles vaccine hesitancy among parents.
Project description:PurposeThe aim of this study is the experimental and Monte Carlo-based determination of small field correction factors for the unshielded silicon detector microSilicon for a standard linear accelerator as well as the Cyberknife System. In addition, a detailed Monte Carlo analysis has been performed by modifying the detector models stepwise to study the influences of the detector's components.MethodsSmall field output correction factors have been determined for the new unshielded silicon diode detector, microSilicon (type 60023, PTW Freiburg, Germany) as well as for the predecessors Diode E (type 60017, PTW Freiburg, Germany) and Diode SRS (type 60018, PTW Freiburg, Germany) for a Varian TrueBeam linear accelerator at 6 MV and a Cyberknife system. For the experimental determination, an Exradin W1 scintillation detector (Standard Imaging, Middleton, USA) has been used as reference. The Monte Carlo simulations have been performed with EGSnrc and phase space files from IAEA as well as detector models according to manufacturer blueprints. To investigate the influence of the detector's components, the detector models have been modified stepwise.ResultsThe correction factors for the smallest field size investigated at the TrueBeam linear accelerator (equivalent dosimetric square field side length Sclin = 6.3 mm) are 0.983 and 0.939 for the microSilicon and Diode E, respectively. At the Cyberknife system, the correction factors of the microSilicon are 0.967 at the smallest 5-mm collimator compared to 0.928 for the Diode SRS. Monte Carlo simulations show comparable results from the measurements and literature.ConclusionThe microSilicon (type 60023) detector requires less correction than its predecessors, Diode E (type 60017) and Diode SRS (type 60018). The detector housing has been demonstrated to cause the largest perturbation, mainly due to the enhanced density of the epoxy encapsulation surrounding the silicon chip. This density has been rendered more water equivalent in case of the microSilicon detector to minimize the associated perturbation. The sensitive volume itself has been shown not to cause observable field size-dependent perturbation except for the volume-averaging effect, where the slightly larger diameter of the sensitive volume of the microSilicon (1.5 mm) is still small at the smallest field size investigated with corrections <2%. The new microSilicon fulfils the 5% correction limit recommended by the TRS 483 for output factor measurements at all conditions investigated in this work.
Project description:BackgroundAlthough research demonstrates the necessity of social recovery capital (SRC) for youth in recovery, through having family that do not use substances and who support their recovery, the ways in which parents actually enact SRC have not been empirically examined. This qualitative study applied the Recovery Capital Model for Adolescents to group interview data from parent(s) of youth who resolved a substance use disorder (SUD) to explore the ways parents enacted SRC.MethodThe interviews were conducted in a prior ethnographic study in which parents of alternative peer group (APG) alumni volunteered to participate in a group interview; five mothers and five fathers of APG alumni participated in the interviews (n=10). Three investigators analyzed the interview transcripts using the constant comparative method to identify family SRC and the specific components parents supported their child's recovery.ResultsThe primary themes of parent support of SRC included locus of control, parent growth, and sober/supportive home. Locus of control included parent strategies to leverage youth's participation in treatment/recovery. Parent growth focused on the process of change parents described: from denial to developing insight and learning how to parent a child in addiction. Supportive and structured family included time spent with youth in recovery-related activities and improved communication and relationships.ConclusionsTogether, these themes suggest a process of parent change that supports an adolescent's recovery trajectory and increases parenting skills and coping. These themes also highlight how the APG structure enabled this process, generating potential hypotheses for future recovery-oriented research to address.
Project description:BackgroundCongenital cytomegalovirus (CMV) is the most common infectious cause of congenital disability, which can cause lifelong impairments including sensorineural hearing loss and developmental delay. This study aimed to explore the experiences of parenting a child with congenital CMV and the impact this has on families.MethodsTen parents living with a child with congenital CMV in the UK participated in semistructured interviews and data were analysed using thematic analysis.ResultsThe findings illustrate that delays in making the diagnosis of congenital CMV are associated with parental distress and lack of knowledge about CMV among medical professionals can exacerbate this distress. Parents expressed frustration about not knowing about CMV infection during their pregnancies and therefore not having the opportunity to take measures to reduce their risk of acquiring CMV while pregnant. The uncertainty about the long-term outcomes of children with congenital CMV adds additional emotional burden for parents. Family and wider societal networks have the potential to facilitate coping and alleviate stress, but the lack of awareness of CMV acts as a barrier to receiving support from family and friends.ConclusionsThere is a need to increase awareness of CMV among medical professionals, pregnant women and wider society to improve the diagnostic process and to provide better support for families caring for children with congenital CMV infection.
Project description:BACKGROUND:There are very few close-up sociological or anthropological data informing epidemiological and psychiatric research design and/or contributing to our understanding of the relationship between mental health and specific forms of urban life. Furthermore, research on the relationships between urbanicity and mental disorder has paid little attention to the global diversity of urban experience, such as in cities in China, India and Brazil. METHODS:Two innovative methods can be employed to unveil the diversified urban experience of migrants in China, i.e. an ethnography-informed sociological deep surveying instrument and an ecological momentary assessment with a smartphone app. This article introduces the design and pilot survey of these new instruments towards a 'mechanism-rich' epidemiology. RESULTS:The ethnography-informed survey instrument enabled us to include some of the issues from the ethnography and successfully 'dig deeper' into respondents' social experience. The pilot of the smartphone app serves as 'proof of principle' that we can recruit respondents in Shanghai, and that we can receive and use the data. CONCLUSIONS:Both of these pilots have demonstrated good feasibility for studying mobility, urban life and mental health. Our next steps will be to extend the Shanghai sample, to use the app in Sao Paulo and Toronto and then hopefully in India and Africa.
Project description:Mexico is one of the world's major poultry producing countries. Two significant challenges currently facing the poultry industry are the responsible and judicious use of antimicrobials, and the potential occurrence of infectious disease outbreaks. For example, repeated outbreaks of highly pathogenic avian influenza virus subtype H7N3 have occurred in poultry since its first detection in Mexico in 2012. Both of these challenges can be addressed through good husbandry practices and the application of on-farm biosecurity measures. The aims of this study were: (i) to assess the biosecurity measures practiced across different types of poultry farms in Mexico, and (ii) to collect information regarding antimicrobial usage. A cross-sectional study was carried out through on-farm interviews on 43 poultry farms. A multiple correspondence analysis was performed to characterize the farms based on their pattern of biosecurity practices and antimicrobial usage. Three clusters of farms were identified using an agglomerative hierarchical cluster analysis. In each cluster, a specific farm type was predominant. The biosecurity measures that significantly differentiated the visited farms, thus allowing their clusterization, were: the use of personal protective equipment (e.g. face masks, hair caps, and eye protection), the requirement for a hygiene protocol before and after entering the farm, the use of exclusive working clothes by staff and visitors, footbath presence at the barn entrance, and the mortality disposal strategy. The more stringent the biosecurity measures on farms within a cluster, the fewer the farms that used antimicrobials. Farms with more biosecurity breaches used antimicrobials considered critically important for public health. These findings could be helpful to understand how to guide strategies to reinforce compliance with biosecurity practices identified as critical according to the farm type. We conclude by providing certain recommendations to improve on-farm biosecurity measures.
Project description:This article presents the findings of a qualitative study of maternal perceptions of parenting following participation in Legacy for ChildrenTM (Legacy), an evidence-based parenting program for low-income mothers of young children and infants. To further examine previous findings and better understand participant experiences, we analyzed semistructured focus-group discussions with predominantly Hispanic and Black, non-Hispanic Legacy mothers at two sites (n = 166) using thematic analysis and grounded theory techniques. The qualitative study presented here investigated how mothers view their parenting following participation in Legacy, allowing participants to describe their experience with the program in their own words, thus capturing an "insider" perspective. Mothers at both sites communicated knowledge and use of positive parenting practices targeted by the goals of Legacy; some site-specific differences emerged related to these parenting practices. These findings align with the interpretation of quantitative results from the randomized controlled trials and further demonstrate the significance of the Legacy program in promoting positive parenting for mothers living in poverty. This study emphasizes the importance of understanding real-world context regarding program efficacy and the benefit of using qualitative research to understand participant experiences.