Rate-determining process in MISIM photocells for optoelectronic conversion using photo-induced pure polarization current without carrier transfer across interfaces

Recently, we proposed a [metal|insulator|semiconductor|insulator|metal] (MISIM) photocell, as a novel architecture for high-speed organic photodetectors. The electric polarization in the S layer, induced by modulated light illumination, propagates into the outside circuit as a polarization current through the I layers, without any carrier transfer across the interfaces. In the present work, we examined the MISIM photocells consisting of zinc-phthalocyanine(ZnPc)-C60 bilayers for the S layer and Parylene C for the two I layers, to understand the fundamental aspects of the MISIM photocells, such as current polarity and modulation-frequency dependence. It was found that, in such devices, the current polarity was primarily determined by the polarization in the S layer, which was induced by the donor–acceptor charge-transfer upon illumination. Furthermore, the ON and OFF current, which appeared in the periods of illumination-on and -off, respectively, exhibited significantly different dependence on the modulation frequency. This was well-explained by an imbalance between a quick polarization in the S layer during illumination and its slow relaxation in the dark

Inverse Magnetoresistance of Molecular Junctions

We present calculations of spin-dependent electron transport through single organic molecules bridging pairs of iron nanocontacts. We predict the magnetoresistance of these systems to switch from positive to negative with increasing applied bias for both conducting and insulating molecules. This novel inverse magnetoresistance phenomenon is robust, does not depend on the presence of impurities, and is unique to molecular and atomic nanoscale magnetic junctions. Its physical origin is identified and its relevance to experiment and to potential technological applications is discussed.Comment: 5 pages, 3 figures; published version Phys. Rev.

Supernatants derived from chemotherapy-treated cancer cell lines can modify angiogenesis

BACKGROUND: There is evidence that tumours produce substances such as cytokines and microvesicular bodies bearing bioactive molecules, which support the carcinogenic process. Furthermore, chemotherapy has also been shown to modify these exudates and in doing so, neutralise their tumourigenic influence. METHODS: In the current study, we have investigated the effect of chemotherapy agents on modifying the cytokine profile and microvesicular cargo of supernatants derived from cancer cell lines. In addition, we have explored the effect of these tumour-derived supernatants on angiogenesis, and how chemotherapy can alter the supernatants rendering them less pro-angiogenic. RESULTS: Herein, we show that supernatants contain a rich cocktail of cytokines, a number of which are potent modulators of angiogenesis. They also contain microvesicular bodies containing RNA transcripts that code for proteins involved in transcription, immune modulation and angiogenesis. These supernatants altered intracellular signalling molecules in endothelial cells and significantly enhanced their tubulogenic character; however, this was severely compromised when supernatants from tumours treated with chemotherapy was used instead. CONCLUSION: This study suggests tumour exudates and bioactive material from tumours can influence cellular functions, and that treatment with some chemotherapy can serve to negate these pro-tumourigenic processes

Theoretical Study of Spin-dependent Electron Transport in Atomic Fe Nanocontacts

We present theoretical predictions of spintronic transport phenomena that should be observable in ferromagnetic Fe nanocontacts bridged by chains of Fe atoms. We develop appropriate model Hamiltonians based on semi-empirical considerations and the known electronic structure of bulk Fe derived from ab initio density functional calculations. Our model is shown to provide a satisfactory description of the surface properties of Fe nano-clusters as well as bulk properties. Lippmann-Schwinger and Green's function techniques are used together with Landauer theory to predict the current, magneto-resistance, and spin polarization of the current in Fe nanocontacts bridged by atomic chains under applied bias. Unusual device characteristics are predicted including negative magneto-resistance and spin polarization of the current, as well as spin polarization of the current for anti-parallel magnetization of the Fe nanocontacts under moderate applied bias. We explore the effects that stretching the atomic chain has on the magneto-resistance and spin polarization and predict a cross-over regime in which the spin polarization of the current for parallel magnetization of the contacts switches from negative to positive. We find resonant transmission due to dangling bond formation on tip atoms as the chain is stretched through its breaking point to play an important role in spin-dependent transport in this regime. The physical mechanisms underlying the predicted phenomena are discussed.Comment: 13 pages, 6 figures, Accepted for publication in Physical Review

Examining the shared and unique features of self-concept content and structure in Borderline Personality Disorder and Depression

AcceptedArticleCopyright © Springer Science+Business Media New York 2015The online version of this article (doi:10.1007/s10608-015-9695-3) contains supplementary material, which is available to authorized users.A number of clinical theories emphasise self-concept disturbance as central to borderline personality disorder (BPD). To date, however, there has been limited empirical examination of exactly how BPD changes the content and structure of self-concept. Moreover, it is unclear if patterns of self-concept disturbance are unique to BPD or are driven by axis-I comorbidities such as depression. To examine this issue, the present study adopted a dimensional design, examining how performance on a novel adaptation of a well-validated measure of self-concept (the Psychological Distance Scaling Task) was related to BPD and depression symptoms in a sample of 93 individuals with a wide range of symptom severity. While greater BPD severity was associated with less positive and more negative content of self-concept, this was driven by depression symptoms. Similarly, positive content was more diffuse and negative content more interconnected at higher levels of BPD severity, but for positive content, this was most clearly linked to comorbid depression features. In contrast, BPD severity (over and above depression symptoms) was uniquely associated with greater ‘clustering’ for positive and negative content (i.e. a more fragmented self-concept). This pattern of results lends support to clinical theories arguing that self-concept fragmentation is core to BPD and also supports the utility of dimensional analyses to identify patterns of cognitive-affective disturbance unique to BPD versus those shared with comorbid conditions like depression.MR

Suite2p: beyond 10,000 neurons with standard two-photon microscopy

Two-photon microscopy of calcium-dependent sensors has enabled unprecedented recordings from vast populations of neurons. While the sensors and microscopes have matured over several generations of development, computational methods to process the resulting movies remain inefficient and can give results that are hard to interpret. Here we introduce Suite2p: a fast, accurate and complete pipeline that registers raw movies, detects active cells, extracts their calcium traces and infers their spike times. Suite2p runs on standard workstations, operates faster than real time, and recovers ~2 times more cells than the previous state-of-the-art method. Its low computational load allows routine detection of ~10,000 cells simultaneously with standard two-photon resonant-scanning microscopes. Recordings at this scale promise to reveal the fine structure of activity in large populations of neurons or large populations of subcellular structures such as synaptic boutons

Culture and the remembering of trauma

This research investigated the influence of culture and posttraumatic stress disorder (PTSD) on global autobiographical remembering (Study 1a) and on the phenomenological properties (Study 1b) and memory-content variables (Study 1c) of trauma-specific autobiographical remembering. Australian, British, and Iranian trauma survivors with and without PTSD completed the Autobiographical Memory Test, Self-Defining Memory Task, and Autobiographical Memory Questionnaire and provided trauma- and negative-memory narratives. We found that there were pan-cultural deficits and distortions in the global autobiographical remembering of participants with PTSD (Study 1a). In addition, the presence of PTSD moderated the usual effect of culture on the phenomenological properties of the trauma memory (Study 1b). Finally, participants with PTSD, regardless of cultural background, had significantly fewer expressions of autonomy and self-determination in their autobiographical remembering than did those without PTSD (Study 1c). The findings suggest that pan-culturally, individuals with PTSD have similar disruptions and distortions in their autobiographical remembering

Supernatants from lymphocytes stimulated with Bacillus Calmette-Guerin can modify the antigenicity of tumours and stimulate allogeneic T-cell responses

BACKGROUND: Reduced expression of class 1 human leucocyte antigens (HLA1) is often a mechanism by which tumours evade surveillance by the host immune system. This is often associated with an immune function that is unable to mount appropriate responses against disease, which can result in a state that favours carcinogenesis. METHODS: In the current study, we have explored the effects of Bacillus Calmette-Guerin (BCG) on the cytokine output of leucocytes, which is a key determinant in generating antitumour action, and have also assessed the effect of these cytokine cocktails on HLA1 expression in solid tumour cell lines. RESULTS: BCG potently activated a broad range of leucocytes, and also enhanced the production of cytokines that were Th(1)-predominant. Supernatants from BCG-treated leucocytes significantly increased the expression of HLA1 on the surface of cancer cell lines, which correlated with increased cytolytic T-cell activity. We also showed that the increased HLA1 expression was associated with activation of intracellular signalling pathways, which was triggered by the increases in the Th(1)-cytokines interferon-γ and tumour necrosis factor-α, as counteracting their effects negated the enhancement. CONCLUSION: These studies reaffirm the role of BCG as a putative immunotherapy through their cytokine-modifying effects on leucocytes and their capacity to enhance tumour visibility

Results of a randomized, double-blind phase II clinical trial of NY-ESO-1 vaccine with ISCOMATRIX adjuvant versus ISCOMATRIX alone in participants with high-risk resected melanoma.

BACKGROUND: To compare the clinical efficacy of New York Esophageal squamous cell carcinoma-1 (NY-ESO-1) vaccine with ISCOMATRIX adjuvant versus ISCOMATRIX alone in a randomized, double-blind phase II study in participants with fully resected melanoma at high risk of recurrence. METHODS: Participants with resected stage IIc, IIIb, IIIc and IV melanoma expressing NY-ESO-1 were randomized to treatment with three doses of NY-ESO-1/ISCOMATRIX or ISCOMATRIX adjuvant administered intramuscularly at 4-week intervals, followed by a further dose at 6 months. Primary endpoint was the proportion free of relapse at 18 months in the intention-to-treat (ITT) population and two per-protocol populations. Secondary endpoints included relapse-free survival (RFS) and overall survival (OS), safety and NY-ESO-1 immunity. RESULTS: The ITT population comprised 110 participants, with 56 randomized to NY-ESO-1/ISCOMATRIX and 54 to ISCOMATRIX alone. No significant toxicities were observed. There were no differences between the study arms in relapses at 18 months or for median time to relapse; 139 vs 176 days (p=0.296), or relapse rate, 27 (48.2%) vs 26 (48.1%) (HR 0.913; 95% CI 0.402 to 2.231), respectively. RFS and OS were similar between the study arms. Vaccine recipients developed strong positive antibody responses to NY-ESO-1 (p≤0.0001) and NY-ESO-1-specific CD4+ and CD8+ responses. Biopsies following relapse did not demonstrate differences in NY-ESO-1 expression between the study populations although an exploratory study demonstrated reduced (NY-ESO-1)+/Human Leukocyte Antigen (HLA) class I+ double-positive cells in biopsies from vaccine recipients performed on relapse in 19 participants. CONCLUSIONS: The vaccine was well tolerated, however, despite inducing antigen-specific immunity, it did not affect survival endpoints. Immune escape through the downregulation of NY-ESO-1 and/or HLA class I molecules on tumor may have contributed to relapse