Improving the Stability of High and Low Bandgap Polymers Organic Photovoltaic Devices Using a Solution Based Titanium Sub-Oxide Interfacial Layer

The improvement in device efficiency has brought organic photovoltaic (OPV) devices closer to commercial viability, highlighting the importance of studying the lifetime and stability of OPV devices. At present, the lifetime and stability of OPV devices is much shorter and poor mainly caused by oxygen, moisture, and light resulting in the oxidation on low work function electrodes and the degradation of the morphology of the photoactive layer. To improve the lifetime and stability of the OPV devices, we used newly developed low bandgap polymer, PCDTBT, as the electron acceptor material and a solution based titanium sub-oxide (TiOx) interfacial layer inserted between the active layer and the cathode. In our experiment, we fabricated unencapsulated bulk heterojunctions OPV devices based on the high and low bandgap polymers of P3HT:PC61BM and PCDTBT:PC71BM, respectively. We synthesized a solution based TiOx by using a sol-gel chemistry method. We performed stability tests on the OPV devices: (1) with and without the TiOx layer (Case (I)) to test the effectiveness of the TiOx layer in protecting the photoactive layer from degradation, (2) with and without a protection cover (a high research grade opaque Al foil) to observe the device performance in a dark/light environment (Case (II)), and (3) in different storage media conditions: (a) air, (b) glove box, (3) ante-chamber of a glove box, and (4) (Case (III)). We spent significant time and effort in optimizing the fabrication processing steps including; the thickness of the active layer, pre-annealing and post-annealing treatments. We fabricated the OPV devices by using the optimal fabrication procedure. We found that the best PCE value of 4.1% achieved for the P3HT:PC61BM OPV cell and 5.1% for the PCDTBT:PC71BM OPV cell. On the air stability test, we found that the OPV cell of P3HT:PC61BM materials showed good air stability performance resulting in the PCE only dropping 26% over a period of 70 days (stored in a glove box). The PCDTBT:PC71BM devices stored in the glove box over a period of 30 days showed relatively good air stability performances; (1) the device with a TiOx, layer and an opaque Al cover the PCE dropped only 16%, (2) the device with the TiOx layer and without an opaque Al cover PCE dropped 34%, and (3) the device without a TiO x, layer and with an Al cover PCE dropped 48%. While the PCDTBT:PC71BM devices stored in the air; (1-2) with a TiOx layer and with/without opaque Al covers the PCE values dropped 92% after 18 days, and (3) without the TiOx, layer and with an opaque Al cover, the PCE dropped 100% after 3 days. These results highlight the effectiveness of the TiOx layer in protecting the active layer from degradation. We concluded that the TiOx, layer effectively improved the stability the OPV devices

How Should Therapists Respond to Client Accounts of Out-of-Body Experience?

During an out-of-body experience (OBE) a person experiences their center of consciousness from a spatial location that is distinctly different to their physical body. Prior research has suggested that psychologists and psychotherapists may be reluctant to discuss the content of their clients OBE accounts due to a lack of understanding about the nature of these experiences. Yet, other research has highlighted the substantial value of discussing OBEs in the therapeutic process. This paper examines the literature in order to assess the value of utilizing person-centered dialogue and guided visualisation as counselling approaches for working with clients who have had OBEs

Impact of EU Medical Device Directive on Medical Device Software

Directive 2007/47/EC of the European Parliament amending Medical Device Directive (MDD) provides medical device manufacturers with a compliance framework. However, the effects of the amendments to the MDD on competition in the U.S. medical device software industry are unknown. This study examined the impact of this directive on the competitiveness of U.S. medical device software companies, the safety and efficacy of medical device software, employee training, and recruitment. The conceptual framework for this study included 3 dimensions of medical device regulations: safety, performance, and reliability. The overall research design was a concurrent mixed method study using both quantitative and qualitative techniques. The qualitative techniques involved case studies of 5 purposively selected companies. Data collection involved both surveys and interviews. The sample consisted of 56 employees within medical device firms with markets around the European regions. Qualitative data analysis consisted of descriptive thematic analysis along the study questions and hypotheses and summative evaluation. Quantitative data analysis included descriptive statistics and correlation to test the 4 hypotheses. The results suggested that the MDD has realigned medical device software manufacturing practices, and US medical device companies have gained global competitiveness in improving product safety and increasing sales revenue. Key recommendations to medical device manufacturers include adopting MDD 93/42/EEC, using model-based approaches, and being comprehensive in model use. Adopting the MDD will provide positive social change to patients, as human safety improves with better product quality while companies experience fewer product recalls

Workshops @ Your Library - Spring 2022

Catalog of workshops being offered by the Mississippi State University Libraries during the Spring 2022 semester.https://scholarsjunction.msstate.edu/libworkshops/1009/thumbnail.jp

The Toxoplasma gondii active serine hydrolase 4 regulates parasite division and intravacuolar parasite architecture

ABSTRACT Hydrolase are enzymes that regulate diverse biological processes, including posttranslational protein modifications. Recent work identified four active serine hydrolases (ASHs) in Toxoplasma gondii as candidate depalmitoylases. However, only TgPPT1 (ASH1) has been confirmed to remove palmitate from proteins. ASH4 (TgME49_264290) was reported to be refractory to genetic disruption. We demonstrate that recombinant ASH4 is an esterase that processes short acyl esters but not palmitoyl thioesters. Genetic disruption of ASH4 causes defects in cell division and premature scission of parasites from residual bodies. These defects lead to the presence of vacuoles with a disordered intravacuolar architecture, with parasites arranged in pairs around multiple residual bodies. Importantly, we found that the deletion of ASH4 correlates with a defect in radial dispersion from host cells after egress. This defect in dispersion of parasites is a general phenomenon that is observed for disordered vacuoles that occur at low frequency in wild-type parasites, suggesting a possible general link between intravacuolar organization and dispersion after egress. IMPORTANCE This work defines the function of an enzyme in the obligate intracellular parasite Toxoplasma gondii. We show that this previously uncharacterized enzyme is critical for aspects of cellular division by the parasite and that loss of this enzyme leads to parasites with cell division defects and which also are disorganized inside their vacuoles. This leads to defects in the ability of the parasite to disseminate from the site of an infection and may have a significant impact on the parasite's overall infectivity of a host organism

An agent-based model contrasts opposite effects of dynamic and stable microtubules on cleavage furrow positioning

From experiments by Foe and von Dassow (Foe, V.E., and G. von Dassow. 2008. J. Cell Biol. 183:457–470) and others, we infer a molecular mechanism for positioning the cleavage furrow during cytokinesis. Computer simulations reveal how this mechanism depends on quantitative motor-behavior details and explore how robustly this mechanism succeeds across a range of cell sizes

Outcome of labor in vertex malposition in Cameroon

Background: Vertex malposition is associated with increased maternal and neonatal adverse effects, but its magnitude has not been well established in sub-Saharan women. This study aimed at evaluating labor outcome in cases of Vertex Malposition (VM) in Cameroon.Methods: This prospective cohort study was conducted in the University Teaching Hospital of Yaoundé (Cameroon) from March 1st, 2013 to February 28th, 2014. Women carrying singletons with or without VM in labor were monitored during labor. The main variables recorded included the duration of the second stage of labor, mode of delivery, birth weight and neonatal wellbeing. Data of women with VM were compared to those of women without it. Fisher’s exact test and t-test were used for comparison where appropriate. P<0.05 was considered statistically significant.Results: A total of 100 women were recruited in each group. There was no difference in the mean birth weights (P=0.56). VM was significantly associated with prolonged second stage of labor (RR 12.1, 95%CI 4.4-33.1), cesarean section (RR 12.6, 95%CI 5.3-30), instrumental delivery (RR 7.7, 95%CI 2.6-22.3), episiotomy (RR 6.2, 95%CI 2.8-13.7) and neonatal death (RR 8, 95%CI 1.01-62.7).Conclusions: VM is associated with increased maternal and neonatal adverse effects. Hence, delivery should be carried out in settings where cesarean section, instrumental delivery and neonatal resuscitation can rapidly be performed.

Stable and dynamic microtubules coordinately shape the myosin activation zone during cytokinetic furrow formation

The cytokinetic furrow arises from spatial and temporal regulation of cortical contractility. To test the role microtubules play in furrow specification, we studied myosin II activation in echinoderm zygotes by assessing serine19-phosphorylated regulatory light chain (pRLC) localization after precisely timed drug treatments. Cortical pRLC was globally depressed before cytokinesis, then elevated only at the equator. We implicated cell cycle biochemistry (not microtubules) in pRLC depression, and differential microtubule stability in localizing the subsequent myosin activation. With no microtubules, pRLC accumulation occurred globally instead of equatorially, and loss of just dynamic microtubules increased equatorial pRLC recruitment. Nocodazole treatment revealed a population of stable astral microtubules that formed during anaphase; among these, those aimed toward the equator grew longer, and their tips coincided with cortical pRLC accumulation. Shrinking the mitotic apparatus with colchicine revealed pRLC suppression near dynamic microtubule arrays. We conclude that opposite effects of stable versus dynamic microtubules focuses myosin activation to the cell equator during cytokinesis