Hyperfine interaction and magnetoresistance in organic semiconductors

We explore the possibility that hyperfine interaction causes the recently discovered organic magnetoresistance (OMAR) effect. Our study employs both experiment and theoretical modelling. An excitonic pair mechanism model based on hyperfine interaction, previously suggested by others to explain magnetic field effects in organics, is examined. Whereas this model can explain a few key aspects of the experimental data, we, however, uncover several fundamental contradictions as well. By varying the injection efficiency for minority carriers in the devices, we show experimentally that OMAR is only weakly dependent on the ratio between excitons formed and carriers injected, likely excluding any excitonic effect as the origin of OMAR.Comment: 10 pages, 7 figures, 1 tabl

P4‐154: The Protein Quality Control Protein, Ubiquilin‐2, Regulates Tau Accumulation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152960/1/alzjjalz2019063816.pd

Nonlinear Dynamics of the Perceived Pitch of Complex Sounds

We apply results from nonlinear dynamics to an old problem in acoustical physics: the mechanism of the perception of the pitch of sounds, especially the sounds known as complex tones that are important for music and speech intelligibility

Large losses from little lies: Strategic gender misrepresentation and cooperation

This paper investigates the possibility that a small deceptive act of misrepresenting one's gender to others reduces cooperation in the Golden Balls game, a variant of a prisoner's dilemma game. Compared to treatments where either participants' true genders are revealed to each other in a pair or no information on gender is given, the treatment effects of randomly selecting people to be allowed to misrepresent their gender on defection are positive, sizeable, and statistically significant. Allowing people to misrepresent their gender reduces the average cooperation rate by approximately 10-12 percentage points. While one explanation for the significant treatment effects is that participants who chose to misrepresent their gender in the treatment where they were allowed to do so defect substantially more, the potential of being matched with someone who could be misrepresenting their gender also caused people to defect more than usual as well. On average, individuals who chose to misrepresent their gender are around 32 percentage points more likely to defect than those in the blind and true gender treatments. Further analysis reveals that a large part of the effect is driven by women who misrepresented in same-sex pairs and men who misrepresented in mixed-sex pairs. We conclude that even small short-term opportunities to misrepresent one's gender can potentially be extremely harmful to later human cooperation

Randomized controlled trial comparing magnetic marker localization (MaMaLoc) with wire-guided localization in the treatment of early-stage breast cancer

Wire-guided localization (WGL) is the standard of care in the surgical treatment of nonpalpable breast tumors. In this study, we compare the use of a new magnetic marker localization (MaMaLoc) technique to WGL in the treatment of early-stage breast cancer patients. Open-label, single-center, randomized controlled trial comparing MaMaLoc (intervention) to WGL (control) in women with early-stage breast cancer. Primary outcome was surgical usability measured using the System Usability Scale (SUS, 0-100 score). Secondary outcomes were patient reported, clinical, and pathological outcomes such as retrieval rate, operative time, resected specimen weight, margin status, and reoperation rate. Thirty-two patients were analyzed in the MaMaLoc group and 35 in the WGL group. Patient and tumor characteristics were comparable between groups. No in situ complications occurred. Retrieval rate was 100% in both groups. Surgical usability was higher for MaMaLoc: 70.2 ± 8.9 vs. 58.1 ± 9.1, p < 0.001. Patients reported higher overall satisfaction with MaMaLoc (median score 5/5) versus WGL (score 4/5), p < 0.001. The use of magnetic marker localization (MaMaLoc) for early-stage breast cancer is effective and has higher surgical usability than standard WGL

Epigenetics as a mechanism driving polygenic clinical drug resistance

Aberrant methylation of CpG islands located at or near gene promoters is associated with inactivation of gene expression during tumour development. It is increasingly recognised that such epimutations may occur at a much higher frequency than gene mutation and therefore have a greater impact on selection of subpopulations of cells during tumour progression or acquisition of resistance to anticancer drugs. Although laboratory-based models of acquired resistance to anticancer agents tend to focus on specific genes or biochemical pathways, such 'one gene : one outcome' models may be an oversimplification of acquired resistance to treatment of cancer patients. Instead, clinical drug resistance may be due to changes in expression of a large number of genes that have a cumulative impact on chemosensitivity. Aberrant CpG island methylation of multiple genes occurring in a nonrandom manner during tumour development and during the acquisition of drug resistance provides a mechanism whereby expression of multiple genes could be affected simultaneously resulting in polygenic clinical drug resistance. If simultaneous epigenetic regulation of multiple genes is indeed a major driving force behind acquired resistance of patients' tumour to anticancer agents, this has important implications for biomarker studies of clinical outcome following chemotherapy and for clinical approaches designed to circumvent or modulate drug resistance

Liquid-Ordered Phase Formation by Mammalian and Yeast Sterols: A Common Feature With Organizational Differences

Here, biophysical properties of membranes enriched in three metabolically related sterols are analyzed both in vitro and in vivo. Unlike cholesterol and ergosterol, the common metabolic precursor zymosterol is unable to induce the formation of a liquid ordered (lo) phase in model lipid membranes and can easily accommodate in a gel phase. As a result, Zym has a marginal ability to modulate the passive membrane permeability of lipid vesicles with different compositions, contrary to cholesterol and ergosterol. Using fluorescence-lifetime imaging microscopy of an aminostyryl dye in living mammalian and yeast cells we established a close parallel between sterol-dependent membrane biophysical properties in vivo and in vitro. This approach unraveled fundamental differences in yeast and mammalian plasma membrane organization. It is often suggested that, in eukaryotes, areas that are sterol-enriched are also rich in sphingolipids, constituting highly ordered membrane regions. Our results support that while cholesterol is able to interact with saturated lipids, ergosterol seems to interact preferentially with monounsaturated phosphatidylcholines. Taken together, we show that different eukaryotic kingdoms developed unique solutions for the formation of a sterol-rich plasma membrane, a common evolutionary trait that accounts for sterol structural diversity.Peer Reviewe

Biological control of broad mites (Polyphagotarsonemus latus) with the generalist predator Amblyseius swirskii

The broad mite is a serious pest of a variety of crops worldwide. Several phytoseiid mites have been described to control these mites. However, broad mites are still one of the major pest problems on greenhouse pepper in South-eastern Spain. The generalist predatory mite A. swirskii is widely used against other pests of pepper plants such as thrips and whiteflies, the latter being a vector of broad mites. We assessed the potential of A. swirskii to control broad mites. The oviposition rate of A. swirskii on a diet of broad mites was lower than on a diet of pollen, but higher than oviposition in the absence of food. Population-dynamical experiments with A. swirskii on single sweet pepper plants in a greenhouse compartment showed successful control of broad mites