Analytic Examples, Measurement Models and Classical Limit of Quantum Backflow

We investigate the backflow effect in elementary quantum mechanics - the phenomenon in which a state consisting entirely of positive momenta may have negative current and the probability flows in the opposite direction to the momentum. We compute the current and flux for states consisting of superpositions of gaussian wave packets. These are experimentally realizable but the amount of backflow is small. Inspired by the numerical results of Penz et al (M.Penz, G.Gr\"ubl, S.Kreidl and P.Wagner, J.Phys. A39, 423 (2006)), we find two non-trivial wave functions whose current at any time may be computed analytically and which have periods of significant backflow, in one case with a backwards flux equal to about 70 percent of the maximum possible backflow, a dimensionless number $c_{bm} \approx 0.04$, discovered by Bracken and Melloy (A.J.Bracken and G.F.Melloy, J.Phys. A27, 2197 (1994)). This number has the unusual property of being independent of $\hbar$ (and also of all other parameters of the model), despite corresponding to an obviously quantum-mechanical effect, and we shed some light on this surprising property by considering the classical limit of backflow. We discuss some specific measurement models in which backflow may be identified in certain measurable probabilities.Comment: 33 pages, 14 figures. Minor revisions. Published versio

The Late Quaternary geology of the Housatonic River basin in southwestern Massachusetts and adjacent Connecticut

Guidebook for field trips in western Massachusetts, northern Connecticut and adjacent areas of New York: 67th annual meeting October 10, 11, and 12, 1975: Trip B-7; C-

Viral evasion of innate immune defense: The case of resistance of pandemic H1N1 influenza A virus to human mannose-binding proteins

Mannose-binding lectins effectively inhibit most seasonal strains of influenza A virus and contribute to the innate host defense vs. these viruses. In contrast, pandemic IAV strains are largely resistant to these lectins, likely contributing to increased spread and worse outcomes. In this paper, we evaluated the inhibition of IAV by mannose-binding lectins of human, bacterial, and fungal origin to understand and possibly increase activity vs. the pandemic IAV. A modified version of the human surfactant protein D (SP-D) neck and carbohydrate recognition domain (NCRD) with combinatorial substitutions at the 325 and 343 positions, previously shown to inhibit pandemic H3N2 IA

Alzheimer's Associated β-Amyloid Protein Inhibits Influenza A Virus and Modulates Viral Interactions with Phagocytes

Accumulation of β-Amyloid (βA) is a key pathogenetic factor in Alzheimer's disease; however, the normal function of βA is unknown. Recent studies have shown that βA can inhibit growth of bacteria and fungi. In this paper we show that βA also inhibits replication of seasonal and pandemic strains of H3N2 and H1N1 influenza A virus (IAV) in vitro. The 42 amino acid fragment of βA (βA42) had greater activity than the 40 amino acid fragment. Direct incubation of the virus with βA42 was needed to achieve optimal inhibition. Using quantitative PCR assays βA42 was shown to reduce viral uptake by epithelial cells after 45 minutes and to reduce supernatant virus at 24 hours post infection. βA42 caused aggregation of IAV particles as detected by light transmission assays and electron and confocal microscopy. βA42 did not stimulate neutrophil H2O2 production or extracellular trap formation on its own, but it increased both responses stimulated by IAV. In addition, βA42 increased uptake of IAV by neutrophils. βA42 reduced viral protein synthesis in monocytes and reduced IAV-induced interleukin-6 production by these cells. Hence, we demonstrate for the first time that βA has antiviral activity and modulates viral interactions with phagocytes

A Longitudinal Examination of the Measurement Properties and Predictive Utility of the Center for Epidemiologic Studies Depression Scale Among North American Indigenous Adolescents

We examined the longitudinal measurement properties and predictive utility of the Center for Epidemiologic Studies Depression Scale (CES-D) from early to late adolescence among a sample of North American Indigenous youths. Participants were 632 North American Indigenous adolescents (n = 632; 50.3% girls; M age at baseline = 11.11 years) participating in an 8-year, 8-wave longitudinal study. Via in-person interviews, participants completed the CES-D at Waves 1, 3, 5, and 7, and the major depressive disorder (MDD) module of the Diagnostic Interview Schedule for Children at Waves 1, 4, 6, and 8. Confirmatory factor analyses indicated that responses to the CES-D were similarly explained by 2-, 3-, and 4-factor models, as well as a 1-factor model with correlations between the error variances for the positively worded items. Longitudinal measurement equivalence analyses indicated full structural (i.e., factor structure), metric (i.e., factor loadings), and scalar (i.e., observed item intercepts) equivalence for each factor structure. Substantive analyses showed that the CES-D was significantly associated with MDD both concurrently and prospectively, although these effects were smaller than might be expected. Finally, the CES-D negative affect and somatic complaints subscales were the strongest and most consistent predictors of MDD. Among our sample of North American Indigenous youths, the measurement properties of the CES-D were stable from early to late adolescence. Moreover, somatic difficulties and depressed affect were the strongest predictors of MDD

Reduced influenza viral neutralizing activity of natural human trimers of surfactant protein D

BACKGROUND. Surfactant protein D (SP-D) plays important roles in innate host defense against influenza A virus (IAV) infection. Common human polymorphisms of SP-D have been found in many human populations and associated with increased risk of certain infections. We recently reported that the Thr/Thr 11 form of SP-D is associated with low serum levels and assembles predominantly as trimers as opposed to the more common multimeric forms of SP-D. METHODS. Preliminary experiments were done to establish the effects of different monoclonal antibodies against SP-D on ability of SP-D to bind to or neutralize the virus. We then purified natural human trimeric and multimeric forms of SP-D from amniotic fluid and tested ability of these preparations to bind to IAV, to inhibit infectivity and hemagglutination activity of IAV in vitro. RESULTS. In initial experiments mAbs directed against different areas on the CRD of SP-D were found to have differing effects on antiviral activity. Using an mAb that did not interfere with antiviral activity of SP-D, we confirm that natural SP-D trimers had reduced ability to bind to IAV. In addition, the trimers had reduced ability to neutralize IAV as compared to natural human SP-D multimers as well as reduced hemagglutination inhibiting activity against several strains of IAV. Natural SP-D trimers also had different interactions with human neutrophil peptide defensins (HNPs) in viral neutralization assays as compared to multimeric SP-D. CONCLUSION. These studies indicate that a common human polymorphic form of SP-D may modulate host defense against IAV and give impetus to clinical studies correlating this genotype with risk for IAV infection in susceptible groups. We also show that mAbs directed against different areas on the carbohydrate recognition domain of SP-D can be useful for dissecting out different functional properties of the protein

Chicken lung lectin is a functional C-type lectin and inhibits haemagglutination by influenza A virus

Many proteins of the calcium-dependent (C-type) lectin family have been shown to play an important role in innate immunity. They can bind to a broad range of carbohydrates, which enables them to interact with ligands present on the surface of micro-organisms.We previously reported the finding of a new putative chicken lectin, which was predominantly localized to the respiratory tract, and thus termed chicken lung lectin (cLL). In order to investigate the biochemical and biophysical properties of cLL, the recombinant protein was expressed, affinity purified and characterized. Recombinant cLL was expressed as four differently sized peptides, which is most likely due to post-translational modification. Crosslinking of the protein led to the formation of two high-molecular weight products, indicating that cLL forms trimeric and possibly even multimeric subunits. cLL was shown to have lectin activity, preferentially binding to a-mannose in a calcium-dependent manner. Furthermore, cLL was shown to inhibit the haemagglutination-activity of human isolates of influenza A virus, subtype H3N2 and H1N1. These result show that cLL is a true C-type lectin with a very distinct sugar specificity, and that this chicken lectin could play an important role in innate immunity

Mental and substance use disorders from early adolescence to young adulthood among indigenous young people: final diagnostic results from an 8-year panel study

Objective—Our objective was to investigate change in prevalence rates for mental and substance abuse disorders between early adolescence and young adulthood in a cohort of indigenous adolescents who participated in an 8-year panel study. Method—The data are from a lagged, sequential study of 671 indigenous adolescents (Wave 1) from a single culture in the Northern Midwest USA and Canada. At Wave 1 (mean age 11.3 years, Wave 4 (mean age 14.3 years), Wave 6 (mean age 16.2 years), and at Wave 8 (mean age 18.3 years) the tribally enrolled adolescents completed a computer-assisted personal interview that included DISC-R assessment for 11 diagnoses. Our yearly retention rates by diagnostic wave were: Wave 2, 94.7 %; Wave 4, 87.7 %; Wave 6, 88.0 %; Wave 8, 78.5 %. Results—The findings show a dramatic increase in lifetime prevalence rates for substance use disorders. By young adulthood, over half had met criteria of substance abuse or dependence disorder. Also at young adulthood, 58.2 % had met lifetime criteria of a single substance use or mental disorder and 37.2 % for two or more substance use or mental disorders. The results are compared to other indigenous diagnostic studies and to the general population. Conclusions—A mental health crisis exists within the indigenous populations that participated in this study. Innovations within current mental health service systems are needed to address the unmet demand of adolescents and families