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Thermally induced degradation of organic photovoltaic devices hinders the commercialization of this emerging PV technology. Thus, a precise understanding of the origin of thermal device instability, as well as identifying strategies to circumvent degradation is of utmost importance. Here, it investigates thermally‐induced degradation of state‐of‐the‐art PBDB‐T‐2F (PM6):BTP (Y6) bulk heterojunction solar cells at different temperatures and reveal changes of their optical properties, photophysics, and morphology. The open‐circuit voltage and fill factor of thermally degraded devices are limited by dissociation and charge collection efficiency differences, while the short‐circuit current density is only slightly affected. Energy‐resolved electrochemical impedance spectroscopy measurements reveal that thermally degraded samples exhibit a higher energy barrier for the charge‐transfer state to charge‐separated state conversion. Furthermore, the field dependence of charge generation, recombination, and extraction are studied by time‐delayed collection field and transient photocurrent and photovoltage experiments, indicating significant bimolecular recombination limits device performance. Finally, coupled optical‐electrical device simulations are conducted to fit the devices' current‐voltage characteristics, enabling us to find useful correlations between optical and electrical properties of the active layers and device performance parameters. [ABSTRACT FROM AUTHOR]

Herein, a simple, low-cost, solution-processed, and parallel fabrication method to form metal halide perovskite (MHP) poly and single-crystalline films confined in ordered micrometer-sized domains is reported. A cross-linked polydimethylsiloxane (PDMS) stamp featuring 25 μm side squares is used to pattern their substrates. The substrate is microcontact printed on the PDMS inked with self-assembled monolayers (SAMs) of alkanethiol to form a molecular template, resulting in hydrophilic (gold) and hydrophobic (alkanethiol) domains. The subsequent deposition of lead bromide (PbBr2) and methylammonium bromide (MABr) precursor solutions on the pre-patterned substrate resulted in poly and single-crystalline films of methylammonium lead bromide (MAPbBr3) confined to the hydrophilic domains. Two deposition methods: drop-casting and two-step spin-coating are systematically investigated to find well confined and large-sized single-crystal MAPbBr3. Casting proves to be more effective than two-step spin-coating to achieve better confinement of MAPbBr3. The patterning process is monitored in dependence of the a) deposition methods used to b) precisely control the MAPbBr3 crystal growth in a pre-defined site which leads to c) grow poly and single-crystals in a periodic arrangement. Their nondestructive and less energy processable fabrication method will have its own contribution in transferring patterns to desired substrates that enables them to fabricate different types of MHP optoelectronic devices and integrated electronic systems with more complex architectures. [ABSTRACT FROM AUTHOR]

G protein–coupled receptors (GPCRs) are one of the most important drug–target classes in pharmaceutical industry. Their diversity in signaling, which can be modulated with drugs, permits the design of more effective and better-tolerated therapeutics. In this work, we have used rigid oligoproline backbones to generate bivalent ligands for the gastrin-releasing peptide receptor (GRPR) with a fixed distance between their recognition motifs. This allows the stabilization of GPCR dimers irrespective of their physiological occurrence and relevance, thus expanding the space for medicinal chemistry. Specifically, we observed that compounds presenting agonists or antagonists at 20- and 30-Å distance induce GRPR dimerization. Furthermore, we found that 1) compounds with two agonists at 20- and 30-Å distance that induce dimer formation show bias toward Gq efficacy, 2) dimers with 20- and 30-Å distance have different potencies toward β-arrestin-1 and β-arrestin-2, and 3) the divalent agonistic ligand with 10-Å distance specifically reduces Gq potency without affecting β-arrestin recruitment, pointing toward an allosteric effect. In summary, we show that rigid oligoproline backbones represent a tool to develop ligands with biased GPCR signaling. [ABSTRACT FROM AUTHOR]

Current–voltage (IV) characterization is the most fundamental measurement performed on solar cells. This measurement is commonly used to extract basic solar cell parameters, such as open circuit voltage, short circuit current density, fill factor, and power conversion efficiency. We were able to obtain a fast tool to find defective behavior using Simulation Program with Integrated Circuit Emphasis simulations and generate an understanding of which device property can create such defective behaviors by analyzing the second derivative of IV curves. [ABSTRACT FROM AUTHOR]

Background: Glycosphingolipids are important compounds of the plasma membrane of mammalian cells and a number of them have been associated with malignant transformation and progression, reinforcing tumour aggressiveness and metastasis. Here we investigated the levels of naturally occurring anti-glycan antibodies to Globo H in blood plasma obtained from high-grade serous ovarian cancer patients (SOC) and women without gynaecological malignancies (control) using suspension glycan array technology employing chemically synthesized glycans as antibody targets. Results: We found that anti-human Globo H IgG antibodies were able to significantly discriminate SOC from controls (P < 0.05). A combination with the clinically used tumour marker CA125 increased the diagnostic performance (AUC 0.8711). We next compared suspension array with standard flow cytometry in plasma samples and found that the level of anti-Globo H antibodies highly correlated (r = 0.992). The incubation of plasma-derived anti-glycan antibodies with chemically synthesized (presented on fluorescence microspheres) and native Globo H (expressed on Globo H-positive cell lines) revealed strong reactivity of naturally occurring human anti-Globo H antibodies towards its antigen expressed on ovarian cancer cells. Conclusions: Our data demonstrate that human plasma-derived antibodies to Globo H as well as the presence of the antigen might be considered as therapeutic option in ovarian cancer. [ABSTRACT FROM AUTHOR]

Glucosylceramide synthase (GCS) catalyzes the first committed step in the biosynthesis of glucosyl-ceramide (GlcCer)-related glycosphingolipids (GSLs). Although inhibitors of GCS, PPMP and PDMP have been widely used to elucidate their biological function and relevance, our comprehensive literature review revealed that the available data are ambiguous. We therefore investigated whether and to what extent GCS inhibitors affect the expression of lactosylceramide (LacCer), neolacto (nLc4 and P1), ganglio (GM1 and GD3) and globo (Gb3 and SSEA3) series GSLs in a panel of human cancer cell lines using flow cytometry, a commonly applied method investigating cell-surface GSLs after GCS inhibition. Their cell-surface GSL expression considerably varied among cell lines and more importantly, sublethal concentrations (IC10) of both inhibitors preferentially and significantly reduced the expression of Gb3 in the cancer cell lines IGROV1, BG1, HT29 and T47D, whereas SSEA3 was only reduced in BG1. Unexpectedly, the neolacto and ganglio series was not affected. LacCer, the precursor of all GlcCer-related GSL, was significantly reduced only in BG1 cells treated with PPMP. Future research questions addressing particular GSLs require careful consideration; our results indicate that the extent to which there is a decrease in the expression of one or more particular GSLs is dependent on the cell line under investigation, the type of GCS inhibitor and exposure duration. [ABSTRACT FROM AUTHOR]

The article discusses the role of photography in influencing cultures and determines its capacity in validating history. It discusses the issues associated with the use of technology in manipulating images which can represent the truth and has became a powerful tool in hiding the reality. It then relates the personal experience of the author as a journalist in challenging the control of propagandist's power over the media. Moreover, it discusses the emerging advocacy for new expression of the formerly known Third World that challenges the western countries' rhetorics of democracy.

A personal narrative is presented which explores the author's experience of going to Bangladesh after the occurrence of a cyclone in 1991.

The article presents the author's sociocultural observations as a photographer. He describes the lifestyle and experience of other members of the photographic community in Bangladesh. He states that the South Asian School of photography Pathshala's basic course helped break age and class barriers and women photographers were emerging. He feels that South Asian photographers have not received due international recognition and expresses his confidence in them.

Rapid, nondestructive characterization techniques for evaluating the degree of crystallinity and phase segregation of organic semiconductor blend thin films are highly desired for in‐line, automated optoelectronic device fabrication facilities. Here, it is demonstrated that reflection polarized optical microscopy (POM), a simple technique capable of imaging local anisotropy of materials, is capable of determining the relative degree of crystallinity and phase segregation of thin films of polymer:fullerene blends. While previous works on POM of organic semiconductors have largely employed the transmission geometry, it is demonstrated that reflection POM provides 3× greater contrast. The optimal configuration is described to maximize contrast from POM images of polymer:fullerene films, which requires Köhler illumination and slightly uncrossed polarizers, with an uncrossing angle of ±3°. It is quantitatively demonstrated that contrast in POM images directly correlates with 1) the degree of polymer crystallinity and 2) the degree of phase segregation between polymer and fullerene domains. The origin of the bright and dark domains in POM is identified as arising from symmetry‐broken liquid crystalline phases (i.e., dark conglomerates), and it is proven that they have no correlation with surface topography. The use of reflection POM as a rapid diagnostic tool for automated device fabrication facilities is discussed. [ABSTRACT FROM AUTHOR]

The (neo-) lacto series glycosphingolipids (nsGSLs) comprise of glycan epitopes that are present as blood group antigens, act as primary receptors for human pathogens and are also increasingly associated with malignant diseases. Beta-1, 3-N-acetyl-glucosaminyl-transferase 5 (B3GNT5) is suggested as the key glycosyltransferase for the biosynthesis of nsGSLs. In this study, we investigated the impact of CRISPR-Cas9 -mediated gene disruption of B3GNT5 (∆B3GNT5) on the expression of glycosphingolipids and N-glycoproteins by utilizing immunostaining and glycomics-based PGC-UHPLC-ESI-QTOF-MS/MS profiling. ∆B3GNT5 cells lost nsGSL expression coinciding with reduction of α2-6 sialylation on N-glycoproteins. In contrast, disruption of B4GALNT1, a glycosyltransferase for ganglio series GSLs did not affect α2-6 sialylation on N-glycoproteins. We further profiled all known α2-6 sialyltransferase-encoding genes and showed that the loss of α2-6 sialylation is due to silencing of ST6GAL1 expression in ∆B3GNT5 cells. These results demonstrate that nsGSLs are part of a complex network affecting N-glycosylation in ovarian cancer cells. [ABSTRACT FROM AUTHOR]

In this work, we report the fabrication of indium tin oxide free organic solar cells and demonstrate the ability of niobium doped titanium dioxide (TNO) layers produced by sol-gel as feasible alternative electrode. The conductivity of the TNO was tailored by changing the layer thickness and the post-annealing conditions. Later, the crystal structure was revealed by X-ray diffraction. The post-annealing treatments were performed in a rapid thermal processing furnace under different gas atmospheres, temperatures and times. The conductivity of the samples was measured using a four-point set-up and the transparency through a UV-VIS spectrophotometer. A good sheet resistance of 181 Ω/□ is achieved when the electrode was heated in an N2/H2 atmosphere mixture at 1000 °C for 10 min. TNO based organic solar cells were manufactured and their performance was evaluated by current-voltage measurements. A power conversion efficiency of 0.71% was attained. [ABSTRACT FROM AUTHOR]

The article in Macromolecular Rapid Communications discusses the use of reflection polarized optical microscopy (POM) to quickly assess the crystallinity and phase segregation of thin films of organic semiconductor blends. Researchers, including Frédéric Laquai and Christopher Petoukhoff, highlight techniques to enhance POM contrast and reduce aberrations, such as using reflection geometry and Köhler illumination. The study demonstrates a direct correlation between the contrast in POM images and the level of polymer crystallinity and phase segregation in polymer:fullerene blends. [Extracted from the article]

We report a cooperative study conducted between different laboratories to investigate organic solar cell degradation with respect to P3HT material properties and different solar cell architectures. Various batches of P3HT were collected from different suppliers reflecting commercial availability as well as properties variability. Among the materials properties explicitly considered were the molar mass, dispersity, regio-regularity, impurities by trace metals and intrinsic doping evaluated from radical concentrations. Each of the participating laboratories contributing test devices applied their own layer stack, i.e. their own device architecture and layout. This variation was appreciated as another parameter for evaluation. Even though a large amount of devices failed due to extrinsic degradation effects, indeed, some materials properties were found to be more important than others for obtaining long lifetimes and high stability of P3HT-based polymer solar cells. • P3HT:PCBM solar cells made from commercially available P3HTs were aged under three different ISOS protocols. • Solar cells were built by five different labs resulting in 5 different architectures. • The P3HT batches were studied for their properties like impurities, molar mass, dispersity, etc. • All P3HTs performed similar in regard to stability we concluded that commercially available P3HTs offer viable properties. • Layer stack and processor experience with P3HT used had a larger impact on stability than polymer properties. [ABSTRACT FROM AUTHOR]

Current density voltage curves of the solar cell built on sol‐gel processed TiO2:Nb (TNO) and ITO electrodes. Insert graphic shows the energy level diagram of the TNO/ZnO/PEI/ P3HT:PCBM /MoO3/Al organic solar cell. [ABSTRACT FROM AUTHOR]

General design principles of donor–acceptor block copolymers are reviewed and specific results arising from block copolymers consisting of semicrystalline poly(3-hexylthiophene-2,5-diyl) (P3HT) blocks of appreciably high molecular weight and acceptor blocks carrying pendant perylene bisimides or fullerene derivatives are summarized. The chapter is structured according to the building blocks P3HT, poly(perylene bisimide acrylate), and a polystyrene copolymer grafted with phenyl-C61-butyric acid methyl ester used for the synthesis of the corresponding block copolymers, and in each part the synthetic challenges, structure formation, and consequences for charge transport, and in some cases photovoltaic properties, are addressed. [ABSTRACT FROM AUTHOR]