The Lippmann–Schwinger Formula and One Dimensional Models with Dirac Delta Interactions

We show how a proper use of the Lippmann–Schwinger equation simplifies the calculations to obtain scattering states for one dimensional systems perturbed by N Dirac delta equations. Here, we consider two situations. In the former, attractive Dirac deltas perturbed the free one dimensional Schrödinger Hamiltonian. We obtain explicit expressions for scattering and Gamow states. For completeness, we show that the method to obtain bound states use comparable formulas, although not based on the Lippmann–Schwinger equation. Then, the attractive N deltas perturbed the one dimensional Salpeter equation. We also obtain explicit expressions for the scattering wave functions. Here, we need regularisation techniques that we implement via heat kernel regularisation

Protein expression differs between neural progenitor cells from the adult rat brain subventricular zone and olfactory bulb

<p>Abstract</p> <p>Background</p> <p>Neural progenitor cells can be isolated from various regions of the adult mammalian brain, including the forebrain structures of the subventricular zone and the olfactory bulb. Currently it is unknown whether functional differences in these progenitor cell populations can already be found on the molecular level. Therefore, we compared protein expression profiles between progenitor cells isolated from the subventricular zone and the olfactory bulb using a proteomic approach based on two-dimensional gel electrophoresis and mass spectrometry. The subventricular zone and the olfactory bulb are connected by the Rostral Migratory Stream (RMS), in which glial fibrillary acidic protein (GFAP)-positive cells guide neuroblasts. Recent literature suggested that these GFAP-positive cells possess neurogenic potential themselves. In the current study, we therefore compared the cultured neurospheres for the fraction of GFAP-positive cells and their morphology of over a prolonged period of time.</p> <p>Results</p> <p>We found significant differences in the protein expression patterns between subventricular zone and olfactory bulb neural progenitor cells. Of the differentially expressed protein spots, 105 were exclusively expressed in the subventricular zone, 23 showed a lower expression and 51 a higher expression in the olfactory bulb. The proteomic data showed that more proteins are differentially expressed in olfactory bulb progenitors with regard to proteins involved in differentiation and microenvironmental integration, as compared to the subventricular zone progenitors. Compared to 94% of all progenitors of the subventricular zone expressed GFAP, nearly none in the olfactory bulb cultures expressed GFAP. Both GFAP-positive subpopulations differed also in morphology, with the olfactory bulb cells showing more branching. No differences in growth characteristics such as doubling time, and passage lengths could be found over 26 consecutive passages in the two cultures.</p> <p>Conclusion</p> <p>In this study, we describe differences in protein expression of neural progenitor populations isolated from two forebrain regions, the subventricular zone and the olfactory bulb. These subpopulations can be characterized by differential expression of marker proteins. We isolated fractions of progenitor cells with GFAP expression from both regions, but the GFAP-positive cells differed in number and morphology. Whereas in vitro growth characteristics of neural progenitors are preserved in both regions, our proteomic and immunohistochemical data suggest that progenitor cells from the two regions differ in morphology and functionality, but not in their proliferative capacity.</p

Development of a Moderated Online Intervention to Treat Social Anxiety in First-Episode Psychosis.

Background: It is well established that social anxiety disorder (SAD) is a significant clinical problem for individuals with a psychotic disorder. Comorbid social anxiety in individuals with psychosis has been associated with poorer premorbid functioning, increased depression, and a reduced quality of life. Cognitive behavior therapy (CBT) is recommended for people with psychosis as a first-line psychological treatment; however, its focus and evaluation primarily revolves around reducing psychotic symptoms and not necessarily targeting comorbid social anxiety symptoms. We developed a novel online social cognitive behavioral intervention (entitled EMBRACE) specifically designed to treat social anxiety symptoms in first episode psychosis (FEP). Methods: The key clinical and engagement features of the intervention were established through integrating evidence-based material derived from 1) CBT-based treatment models for SAD, 2) relevant literature findings related to psychosis and its clinical correlates (e.g., shame, social rank, and its relationship with social anxiety and paranoia), 3) feedback from youth focus groups in order to inform a user-centered intervention design, and 4) a highly multidisciplinary collaborative development approach to design therapy comics. Results: A detailed description of the final version of the 12-week online social intervention to treat social anxiety in FEP is presented. Conclusion: The EMBRACE intervention was designed to provide young people with the necessary skills and confidence to overcome social anxiety within a supportive, safe online space. By design, it allows young people the opportunity to practice their newly learnt skills to connect with others and in doing so, learn to embrace their true authentic selves

The effect of S-substitution at the O6-guanine site on the structure and dynamics of a DNA oligomer containing a G:T mismatch

The effect of S-substitution on the O6 guanine site of a 13-mer DNA duplex containing a G:T mismatch is studied using molecular dynamics. The structure, dynamic evolution and hydration of the S-substituted duplex are compared with those of a normal duplex, a duplex with Ssubstitution on guanine, but no mismatch and a duplex with just a G:T mismatch. The S-substituted mismatch leads to cell death rather than repair. One suggestion is that the G:T mismatch recognition protein recognises the S-substituted mismatch (GS:T) as G:T. This leads to a cycle of futile repair ending in DNA breakage and cell death. We find that some structural features of the helix are similar for the duplex with the G:T mismatch and that with the S-substituted mismatch, but differ from the normal duplex, notably the helical twist. These differences arise from the change in the hydrogen-bonding pattern of the base pair. However a marked feature of the S-substituted G:T mismatch duplex is a very large opening. This showed considerable variability. It is suggested that this enlarged opening would lend support to an alternative model of cell death in which the mismatch protein attaches to thioguanine and activates downstream damage-response pathways. Attack on the sulphur by reactive oxygen species, also leading to cell death, would also be aided by the large, variable opening

Priming by Chemokines Restricts Lateral Mobility of the Adhesion Receptor LFA-1 and Restores Adhesion to ICAM-1 Nano-Aggregates on Human Mature Dendritic Cells

LFA-1 is a leukocyte specific β2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs) may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into the lymph nodes, by transiently switching its molecular conformational state. However, the role of LFA-1 mobility in this process is not yet known, despite that the importance of lateral organization and dynamics for LFA-1-mediated adhesion regulation is broadly recognized. Using single particle tracking approaches we here show that LFA-1 exhibits higher mobility on resting mDCs compared to monocytes. Lymphoid chemokine CCL21 stimulation of the LFA-1 high affinity state on mDCs, led to a significant reduction of mobility and an increase on the fraction of stationary receptors, consistent with re-activation of the receptor. Addition of soluble monomeric ICAM-1 in the presence of CCL21 did not alter the diffusion profile of LFA-1 while soluble ICAM-1 nano-aggregates in the presence of CCL21 further reduced LFA-1 mobility and readily bound to the receptor. Overall, our results emphasize the importance of LFA-1 lateral mobility across the membrane on the regulation of integrin activation and its function as adhesion receptor. Importantly, our data show that chemokines alone are not sufficient to trigger the high affinity state of the integrin based on the strict definition that affinity refers to the adhesion capacity of a single receptor to its ligand in solution. Instead our data indicate that nanoclustering of the receptor, induced by multi-ligand binding, is required to maintain stable cell adhesion once LFA-1 high affinity state is transiently triggered by inside-out signals.Peer ReviewedPostprint (published version

Designing topographically textured microparticles for induction and modulation of osteogenesis in mesenchymal stem cell engineering

Mesenchymal stem cells are the focus of intense research in bone development and regeneration. The potential of microparticles as modulating moieties of osteogenic response by utilizing their architectural features is demonstrated herein. Topographically textured microparticles of varying microscale features are produced by exploiting phase-separation of a readily soluble sacrificial component from polylactic acid. The influence of varying topographical features on primary human mesenchymal stem cell attachment, proliferation and markers of osteogenesis is investigated. In the absence of osteoinductive supplements, cells cultured on textured microparticles exhibit notably increased expression of osteogenic markers relative to conventional smooth microparticles. They also exhibit varying morphological, attachment and proliferation responses. Significantly altered gene expression and metabolic profiles are observed, with varying histological characteristics in vivo. This study highlights how tailoring topographical design offers cell-instructive 3D microenvironments which allow manipulation of stem cell fate by eliciting the desired downstream response without use of exogenous osteoinductive factors

Photocatalytic Template Removal by Non-Ozone-Generating UV Irradiation for the Fabrication of Well-Defined Mesoporous Inorganic Coatings

The processing of mesoporous inorganic coatings typically requires a high-temperature calcination step to remove organic precursors that are essential during the material assembly. Lowering the fabrication energy costs and cutting back on the necessary resources would provide a greater scope for the deployment in applications such as architectural glass, optical components, photovoltaic cells, and energy storage, as well as further compatibilize substrates with low temperature stability. Organic removal methods based on UV–ozone treatment are increasing in popularity, but concerns remain regarding large-scale ozone generation and usage of mercury-containing UV lamps. To this end, we present a method that relies on non-ozone-generating UV radiation at 254 nm (UV254) and incorporation of small amounts of photocatalytic material in the formulation, here demonstrated with TiO2 nanocrystals. At concentrations as low as 5 wt % relative to the main inorganic aluminosilicate material, the TiO2 nanocrystals catalyze a “cold combustion” of the organic components under UV254 irradiation to reveal a porous inorganic network. Using block copolymer-based co-assembly in conjunction with photocatalytic template removal, we produce well-defined mesoporous inorganic thin films with controlled porosity and refractive index values, where the required processing time is governed by the amount of TiO2 loading. This approach provides an inexpensive, flexible, and environmentally friendly alternative to traditional organic removal techniques, such as UV–ozone degradation and thermal calcination

Qualidade de vida nas pessoas com esquizofrenia: a influência das características sociodemográficas e clínicas e da satisfação com o suporte social

Objective: To evaluate the relationship of sociodemographic and clinical characteristics and satisfaction with social support with the quality of life of schizophrenic patients. Methodology: This study included a sample of 268 participants. An interview was conducted to obtain sociodemographic and clinical data, supplemented with two assessment tools used to evaluate quality of life (World Health Organization Quality of Life instrument-Abbreviated version – WHOQOL-Bref) and satisfaction with social support (Social Support Satisfaction Scale – SSSS). Descriptive and inferential analyses were performed. Results: Most individuals were male (63.4%), with a mean age of 45.4 years, single (85.4%), living with their family (62.3%) and unemployed (90.3%). As for clinical characteristics, most had the disease for less than 20 years (50.7%), and 55.6% had at least one hospitalization within the last 5 years. Being employed and having had no hospitalization within the last 5 years were positively correlated with one or more WHOQOL-Bref domains. The results of the variables intimacy (p<0.001) and satisfaction with friends (p<0.001) were independently related to the total WHOQOL-Bref score. Conclusion: Having a job, having had no hospitalization within the last 5 years and having greater satisfaction with social support are factors that positively influence quality of life among schizophrenics. It is therefore crucial that the psychosocial rehabilitation of patients with schizophrenia take these factors into account, increasing the support network, preventing relapses and promoting occupational activities.Objetivo: Avaliar a relação entre as características sociodemográficas e clínicas e a satisfação com o suporte social com a qualidade de vida dos doentes com esquizofrenia. Métodos: A amostra do estudo é de 268 participantes. Foi realizada uma entrevista para obter os dados sociodemográficos e clínicos e aplicados dois questionários para avaliar a qualidade de vida (World Health Organization Quality of Life instrument-Abbreviated version – WHOQOL-Bref) e a satisfação com o suporte social (Escala de Satisfação com o Suporte Social – ESSS). Foram efetuadas análises descritivas e inferenciais. Resultados: A maioria dos indivíduos era do gênero masculino (63,4%), com uma média de idade de 45,4 anos, solteiros (85,4%), vivendo com a família (62,3%) e desempregados (90,3%). Relativamente às características clínicas, 50,7% tinham a doença há menos de 20 anos, e 55,6% estiveram internados pelo menos uma vez nos últimos 5 anos. Os resultados demonstraram que estar empregado e não ter sido internado nos últimos 5 anos estão positivamente relacionados com um ou mais domínios da WHOQOL-Bref. A satisfação com a intimidade (p<0,001) e a satisfação com os amigos (p<0,001) foram independentemente associados ao escore total da WHOQOL-Bref. Conclusão: Ter emprego, não ter hospitalizações nos últimos 5 anos e estar satisfeito com o suporte social são fatores que influenciam positivamente a qualidade de vida dos doentes com esquizofrenia. Por conseguinte, é crucial que esses fatores sejam levados em conta nos programas de reabilitação com o suporte social, aumentando a rede de suporte, evitando recaídas e promovendo atividades ocupacionais.publishe

High-performance predictor for critical unstable generators based on scalable parallelized neural networks

A high-performance predictor for critical unstable generators (CUGs) of power systems is presented in this paper. The predictor is driven by the MapReduce based parallelized neural networks. Specifically, a group of back propagation neural networks (BPNNs), fed by massive response trajectories data, are efficiently organized and concurrently trained in Hadoop to identify dynamic behaviour of individual generator. Rather than simply classifying global stability of power systems, the presented approach is able to distinguish unstable generators accurately with a few cycles of synchronized trajectories after fault clearing, enabling more in-depth emergency awareness based on wide-area implementation. In addition, the technique is of rich scalability due to Hadoop framework, which can be deployed in the control centers as a high-performance computing infrastructure for real-time instability alert. Numerical examples are studied using NPCC 48 machines test system and a realistic power system of China