1,010 research outputs found

    Stability for Line Bundles and Deformed Hermitian-Yang-Mills Equation on Some Elliptic Surfaces

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    We study the twisted ampleness criterion due to Collins, Jacob and Yau on surfaces, which is equivalent to the existence of solutions to the deformed Hermitian-Yang-Mills (dHYM) equation. When XX is a Weierstrass elliptic K3 surface, and LL is a line bundle and ω\omega an ample class such that c1(L)c_1(L) and ω\omega both lie in the span of a section class and a fiber class, we show that LL is always stable with respect to the Bridgeland stability σω,0\sigma_{\omega,0} provided LL has fiber degree 1 and ωc1(L)>0\omega c_1(L)>0. As a corollary, for such LL and ω\omega, whenever LL is twisted ample with respect to ω\omega, or equivalently, LL admits a solution of the dHYM equation, the line bundle LL is σω,0\sigma_{\omega,0}-stable, thus answering a question by Collins and Yau for a class of examples

    Using Latent Class Analyses to Examine Health Disparities among Young Children in Socially Disadvantaged Families during the COVID-19 Pandemic

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    Rising income inequality is strongly linked to health disparities, particularly in regions where uneven distribution of wealth and income has long been a concern. Despite emerging evidence of COVID-19-related health inequalities for adults, limited evidence is available for children and their parents. This study aimed to explore subtypes of families of preschoolers living in the disadvantaged neighborhoods of Hong Kong based on patterns of family hardship and to compare their patterns of parenting behavior, lifestyle practices, and wellbeing during the COVID-19 pandemic. Data were collected from 1338 preschoolers and their parents during March to June 2020. Latent class analysis was performed based on 11 socioeconomic and disease indicators. Multivariate logistic regressions were used to examine associations between identified classes and variables of interest during the COVID-19 pandemic. Four classes of family hardship were identified. Class 1 (45.7%) had the lowest disease and financial burden. Class 2 (14.0%) had the highest financial burden. Class 3 (5.9%) had the highest disease burden. Class 4 (34.5%) had low family income but did not receive government welfare assistance. Class 1 (low hardship) had lower risks of child maltreatment and adjustment problems than Class 2 (poverty) and Class 3 (poor health). However, children in Class 1 (low hardship) had higher odds of suffering psychological aggression and poorer physical wellbeing than those in Class 4 (low income), even after adjusting for child age and gender. The findings emphasize the need to adopt flexible intervention strategies in the time of large disease outbreak to address diverse problems and concerns among socially disadvantaged families

    Evidence of individual differences in the long-term social, psychological, and cognitive consequences of child maltreatment

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    Background: The prevalence and consequences of child maltreatment are alarming, but evidence from studies with long follow-up intervals are limited. This study examined the long-term consequences of child maltreatment in relation to age of onset and follow-up interval. / Methods: The exposed group comprised 63 individuals (aged 13–34 years) with a first-time diagnosis of child maltreatment between 2001 and 2010, whereas the unexposed group comprised 63 individuals who were matched upon gender, age of onset, follow-up period, and poverty status at the index hospital admission but had no medical records of maltreatment in Hong Kong. The participants completed a set of questionnaires on executive functions and mental health and provided blood samples for measurement of IL-6 and IL-10 levels during a health assessment session. / Results: Compared with the unexposed group, the exposed group reported poorer maternal care during childhood (β = −4.64, p < 0.001) and had lower family support (β = −2.97, p = 0.010) and higher inflammatory responses (IL-6: β = 0.15, p = 0.001; IL-10: β = 0.11, p = 0.011) at follow-up. Additionally, the associations of childhood maltreatment exposure with family support and maternal care differed by age of onset and the length of time since exposure. / Conclusions: This matched cohort study highlights childhood maltreatment as a risk factor for systemic inflammation and an indicator of suboptimal social environment, both of which could persist over a long period of time

    A Longitudinal Study of the Relation between Childhood Activities and Psychosocial Adjustment in Early Adolescence

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    Background: Although an increasing body of research shows that excessive screen time could impair brain development, whereas non-screen recreational activities can promote the development of adaptive emotion regulation and social skills, there is a lack of comparative research on this topic. Hence, this study examined whether and to what extent the frequency of early-life activities predicted later externalizing and internalizing problems. Methods: In 2012/13, we recruited Kindergarten 3 (K3) students from randomly selected kindergartens in two districts of Hong Kong and collected parent-report data on children’s screen activities and parent–child activities. In 2018/19, we re-surveyed the parents of 323 students (aged 11 to 13 years) with question items regarding their children’s externalizing and internalizing symptoms in early adolescence. Linear regression analyses were conducted to examine the associations between childhood activities and psychosocial problems in early adolescence. Results: Early-life parent–child activities (β = −0.14, p = 0.012) and child-alone screen use duration (β = 0.15, p = 0.007) independently predicted externalizing problems in early adolescence. Their associations with video game exposure (β = 0.19, p = 0.004) and non-screen recreational parent–child activities (β = −0.14, p = 0.004) were particularly strong. Conclusions: Parent–child play time is important for healthy psychosocial development. More efforts should be directed to urge parents and caregivers to replace child-alone screen time with parent–child play time

    Evaluation of Aerosol Delivery of Nanosuspension for Pre-clinical Pulmonary Drug Delivery

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    Asthma and chronic obstructive pulmonary disease (COPD) are pulmonary diseases that are characterized by inflammatory cell infiltration, cytokine production, and airway hyper-reactivity. Most of the effector cells responsible for these pathologies reside in the lungs. One of the most direct ways to deliver drugs to the target cells is via the trachea. In a pre-clinical setting, this can be achieved via intratracheal (IT), intranasal (IN), or aerosol delivery in the desired animal model. In this study, we pioneered the aerosol delivery of a nanosuspension formulation in a rodent model. The efficiency of different dosing techniques and formulations to target the lungs were compared, and fluticasone was used as the model compound. For the aerosol particle size determination, a ten-stage cascade impactor was used. The mass median aerodynamic diameter (MMAD) was calculated based on the percent cumulative accumulation at each stage. Formulations with different particle size of fluticasone were made for evaluation. The compatibility of regular fluticasone suspension and nanosuspension for aerosol delivery was also investigated. The in vivo studies were conducted on mice with optimized setting. It was found that the aerosol delivery of fluticasone with nanosuspension was as efficient as intranasal (IN) dosing, and was able to achieve dose dependent lung deposition

    Klebsiella pneumoniae Multiresistance Plasmid pMET1: Similarity with the Yersinia pestis Plasmid pCRY and Integrative Conjugative Elements

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    Dissemination of antimicrobial resistance genes has become an important public health and biodefense threat. Plasmids are important contributors to the rapid acquisition of antibiotic resistance by pathogenic bacteria.The nucleotide sequence of the Klebsiella pneumoniae multiresistance plasmid pMET1 comprises 41,723 bp and includes Tn1331.2, a transposon that carries the bla(TEM-1) gene and a perfect duplication of a 3-kbp region including the aac(6')-Ib, aadA1, and bla(OXA-9) genes. The replication region of pMET1 has been identified. Replication is independent of DNA polymerase I, and the replication region is highly related to that of the cryptic Yersinia pestis 91001 plasmid pCRY. The potential partition region has the general organization known as the parFG locus. The self-transmissible pMET1 plasmid includes a type IV secretion system consisting of proteins that make up the mating pair formation complex (Mpf) and the DNA transfer (Dtr) system. The Mpf is highly related to those in the plasmid pCRY, the mobilizable high-pathogenicity island from E. coli ECOR31 (HPI(ECOR31)), which has been proposed to be an integrative conjugative element (ICE) progenitor of high-pathogenicity islands in other Enterobacteriaceae including Yersinia species, and ICE(Kp1), an ICE found in a K. pneumoniae strain causing primary liver abscess. The Dtr MobB and MobC proteins are highly related to those of pCRY, but the endonuclease is related to that of plasmid pK245 and has no significant homology with the protein of similar function in pCRY. The region upstream of mobB includes the putative oriT and shares 90% identity with the same region in the HPI(ECOR31).The comparative analyses of pMET1 with pCRY, HPI(ECOR31), and ICE(Kp1 )show a very active rate of genetic exchanges between Enterobacteriaceae including Yersinia species, which represents a high public health and biodefense threat due to transfer of multiple resistance genes to pathogenic Yersinia strains

    A Conserved Behavioral State Barrier Impedes Transitions between Anesthetic-Induced Unconsciousness and Wakefulness: Evidence for Neural Inertia

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    One major unanswered question in neuroscience is how the brain transitions between conscious and unconscious states. General anesthetics offer a controllable means to study these transitions. Induction of anesthesia is commonly attributed to drug-induced global modulation of neuronal function, while emergence from anesthesia has been thought to occur passively, paralleling elimination of the anesthetic from its sites in the central nervous system (CNS). If this were true, then CNS anesthetic concentrations on induction and emergence would be indistinguishable. By generating anesthetic dose-response data in both insects and mammals, we demonstrate that the forward and reverse paths through which anesthetic-induced unconsciousness arises and dissipates are not identical. Instead they exhibit hysteresis that is not fully explained by pharmacokinetics as previously thought. Single gene mutations that affect sleep-wake states are shown to collapse or widen anesthetic hysteresis without obvious confounding effects on volatile anesthetic uptake, distribution, or metabolism. We propose a fundamental and biologically conserved concept of neural inertia, a tendency of the CNS to resist behavioral state transitions between conscious and unconscious states. We demonstrate that such a barrier separates wakeful and anesthetized states for multiple anesthetics in both flies and mice, and argue that it contributes to the hysteresis observed when the brain transitions between conscious and unconscious states

    Association studies of up to 1.2 million individuals yield new insights into the genetic etiology of tobacco and alcohol use

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    Tobacco and alcohol use are leading causes of mortality that influence risk for many complex diseases and disorders 1 . They are heritable 2,3 and etiologically related 4,5 behaviors that have been resistant to gene discovery efforts 6–11 . In sample sizes up to 1.2 million individuals, we discovered 566 genetic variants in 406 loci associated with multiple stages of tobacco use (initiation, cessation, and heaviness) as well as alcohol use, with 150 loci evidencing pleiotropic association. Smoking phenotypes were positively genetically correlated with many health conditions, whereas alcohol use was negatively correlated with these conditions, such that increased genetic risk for alcohol use is associated with lower disease risk. We report evidence for the involvement of many systems in tobacco and alcohol use, including genes involved in nicotinic, dopaminergic, and glutamatergic neurotransmission. The results provide a solid starting point to evaluate the effects of these loci in model organisms and more precise substance use measures
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