Cell Architecture Research Articles

Resistive switching memories with enhanced durability enabled by mixed-dimensional perfluoroarene perovskite heterostructures.

Hybrid halide perovskites are attractive candidates for resistive switching memories in neuromorphic computing applications due to their mixed ionic-electronic conductivity. Moreover, their exceptional optoelectronic characteristics make them effective as semiconductors in photovoltaics, opening perspectives for self-powered memory elements. These devices, however, remain unexploited, which is related to the variability in their switching characteristics, weak endurance, and retention, which limit their performance and practical use. To address this challenge, we applied low-dimensional perovskite capping layers onto 3D mixed halide perovskites using two perfluoroarene organic cations, namely (perfluorobenzyl)ammonium and (perfluoro-1,4-phenylene)dimethylammonium iodide, forming Ruddlesden-Popper and Dion-Jacobson 2D perovskite phases, respectively. The corresponding mixed-dimensional perovskite heterostructures were used to fabricate resistive switching memories based on perovskite solar cell architectures, showing that the devices based on perfluoroarene heterostructures exhibited enhanced performance and stability in inert and ambient air atmosphere. This opens perspectives for multidimensional perovskite materials in durable self-powered memory elements in the future.

Lightweight Potential of Anisotropic Plate Lattice Metamaterials

Additive manufacturing enables the production of lattice structures, which have been proven to be a superior class of lightweight mechanical metamaterials whose specific stiffness can reach the theoretical limit of the upper Hashin–Shtrikman bound for isotropic cellular materials. To achieve isotropy, complex structures are required, which can be challenging in powder bed additive manufacturing, especially with regard to subsequent powder removal. The present study focuses on the Finite Element Method simulation of 2,5D anisotropic plate lattice metamaterials and the investigation of their lightweight potential. The intentional use of anisotropic structures allows the production of a cell architecture that is easily manufacturable via Laser Powder Bed Fusion (LPBF) while also enabling straightforward optimization for specific load cases. The work demonstrates that the considered anisotropic plate lattices exhibit high weight-specific stiffnesses, superior to those of honeycomb structures, and, simultaneously, a good de-powdering capability. A significant increase in stiffness and the associated surpassing of the upper Hashin–Shtrikman bound due to anisotropy is achievable by optimizing wall thicknesses depending on specific load cases. A stability analysis reveals that, in all lattice structures, plastic deformation is initiated before linear buckling occurs. An analysis of stress concentrations indicates that the introduction of radii at the plate intersections reduces stress peaks and simultaneously increases the weight-specific stiffnesses and thus the lightweight potential. Exemplary samples illustrate the feasibility of manufacturing the analyzed metamaterials within the LPBF process.

Six‐Month Outdoor Performance Study of Stable Perovskite Solar Cells under Real Operating Conditions

Perovskite solar cells have sparked great excitement in the photovoltaics community due to their remarkable efficiency, flexibility, and ability to be synthesized at low cost. However, their instability poses a major roadblock to their widespread adoption. Recognizing this challenge, this work describes the performance of stable perovskite solar cells operating under real‐life conditions in the Paris area. Two state‐of‐the‐art 2D/3D (HOOC(CH2)4NH3)2PbI4/CH3NH3PbI3 encapsulated cells are considered – one with maximum power point tracking and hourly current‐voltage curve measurements, and another connected to a fixed resistive load. Their performance is compared over six months, and a detailed analysis is conducted on the cells’ hysteresis and electrical response to varying weather conditions. Although the first cell starts to degrade after a few months of operation, the second one remains remarkably stable, highlighting critical issues with outdoor tracking. Given that the stability of this perovskite solar cell architecture has already been established under controlled standard conditions for over one year, these exciting findings pave the way for the commercialization of perovskite‐based photovoltaic devices.This article is protected by copyright. All rights reserved.

Enhancing Field Multiplication in IoT Nodes with Limited Resources: A Low-Complexity Systolic Array Solution

Enhancing Field Multiplication in IoT Nodes with Limited Resources: A Low-Complexity Systolic Array Solution

Mechanical and piezoresistive performance of additively manufactured carbon fiber/PA12 hybrid honeycombs

This study investigates a novel self-sensing honeycomb composite structure composed of two distinct cellular layers with differing unit cell architectures, specifically hexagonal and re-entrant designs. Short carbon fiber (CF)/polyamide 12 (PA12) composite filaments with 0, 5 or 15 wt.% CF content were utilized to additively manufacture the honeycomb structures via Fused Filament Fabrication (FFF), and their mechanical and piezoresistive self-sensing characteristics were experimentally investigated under quasi-static in-plane and out-of-plane compression at both room temperature and elevated temperatures. The results reveal that the hybrid hexagonal/re-entrant (HR) honeycombs mechanically outperform their non-hybrid double-layer and single-layer counterparts under in-plane loading, reporting an increase in collapse strength and energy absorption by factors of 1.64 and 2.25, respectively. These improvements are attributed to the mechanical interactions occurring at the interface between the auxetic and non-auxetic layers within the hybrid structure, effectively enhancing its structural attributes. Furthermore, the double-layer honeycombs display excellent strain-sensing capabilities within the elastic regime, with gauge factors reaching values as high as 146. Mechanical tests conducted at elevated temperatures reveal that the CF/PA12 honeycombs retain a significant portion of their elastic modulus, strength and energy absorption even at 125 °C, while maintaining high gauge factors of up to 72.4. These honeycombs also exhibit pronounced thermoresistive behavior, evidenced by a decrease in electrical resistance of up to 41.3 % with increasing temperatures from 25 to 125 °C. Considering their exceptional combination of thermo-mechanical, thermoresistive and piezoresistive characteristics, these hybrid double-layered CF/PA12 honeycombs hold promise for potential applications in multifunctional lightweight structures, offering integrated temperature and strain-sensing capabilities.

Regulation of mitochondrial network architecture and function in mesenchymal stem cells by micropatterned surfaces

Abstract Mitochondrial network architecture, which is closely related to mitochondrial function, is mechanically sensitive and regulated by multiple stimuli. However, the effects of microtopographic cues on mitochondria remain poorly defined. Herein, polycaprolactone (PCL) surfaces were used as models to investigate how micropatterns regulate mitochondrial network architecture and function in rat adipose-derived stem cells (rASCs). It was found that large pit (LP) induced rASCs to form larger and more complex mitochondrial networks. Consistently, the expression of key genes related to mitochondrial dynamics revealed that mitochondrial fusion (MFN1 and MFN2) and midzone fission (DRP1 and MFF) were increased in rASCs on LP. In contrast, the middle pit (MP) enhanced mitochondrial biogenesis, as evidenced by the larger mitochondrial area and higher expression of PGC-1. Both LP and MP promoted ATP production in rASCs. It is likely that LP increased ATP levels through modulating mitochondrial network architecture while MP stimulated mitochondria biogenesis to do so. Our study clarified the regulation of micropatterned surfaces on mitochondria, highlighting the potential of LP and MP as a simple platform to stimulate mitochondria and the subsequent cellular function of MSCs.

Numerical simulation of a highly efficient perovskite solar cell based on FeSi2 photoactive layer

AbstractThe primary aim of this work is to investigate the use iron di‐silicide (FeSi2) as a photoactive layer in order to achieve superior performance in the solar cell architecture—ITO/TiO2/FeSi2/CuSCN/Ni. The optimum thickness of the absorber layer was found to be 1000 nm, which gave optimal properties of the proposed cell—a short‐circuit current density (Jsc) of 51.41 mAm−2, an open‐circuit voltage (Voc) of 0.93 V, a fill factor (FF) of 77.99%, and power conversion efficiency (PCE) of 37.17%. The introduction of an ultrathin interfacial layer between the electron transport layer (ETL), the perovskite interface, and the hole transport layer (HTL) enhanced the electrical output of the proposed solar cell. The Jsc increased to 51.86 mAcm−2, Voc rose to 0.97 V, while FF and PCE increased to 82.86% and 41.84%, respectively. Accordingly, the proposed cell architecture is promising and can be introduced into the manufacturing workflow for commercial applications. Moreover, because of its exceptional photon absorption capabilities, FeSi2 is a potentially excellent photoactive material for solar cell fabrication. The detailed findings of this study have therefore indicated that high‐performance FeSi2‐based solar can be achieved in future.

Abstract PO3-28-09: Does Diffusely Infiltrating Lobular Carcinoma of the Breast Arise from Epithelial-Mesenchymal Hybrid Cells?

Abstract Classic diffusely infiltrating lobular carcinoma has imaging features divergent from the breast cancers originating from the terminal ductal lobular units and from the major lactiferous ducts. Although the term “invasive lobular carcinoma” implies a site of origin within the breast lobular epithelium, we were unable to find evidence supporting this assumption. Exceptional excess of fibrous connective tissue and the unique cell architecture combined with the aberrant features at breast imaging suggest that this breast malignancy has not originated from cells lining the breast ducts and lobules. The only remaining relevant component of the fibroglandular tissue is the mesenchyme. The cells freshly isolated and cultured from diffusely infiltrating lobular carcinoma cases contained epithelial–mesenchymal hybrid cells with both epithelial and mesenchymal properties. The radiologic and histopathologic features of the tumours and expression of the mesenchymal stem cell positive markers CD73, CD90, and CD105 all suggest development in the direction of mesenchymal transition. These hybrid cells have tumour-initiating potential and have been shown to have poor prognosis and resistance to therapy targeted for malignancies of breast epithelial origin. Our work emphasizes the need for new approaches to the diagnosis and therapy of this highly fatal breast cancer subtype. Citation Format: Andras Voros, Laszlo Tabar, Renata Bozo, Orsolya Olah, Katalin Ormandi, Zoltan Vereb, Istvan Nemeth, Peter B. Dean, Olga Puchkova, Ming-Fang Yen, Li-Sheng Chen. Does Diffusely Infiltrating Lobular Carcinoma of the Breast Arise from Epithelial-Mesenchymal Hybrid Cells? [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-28-09.

A Redox-Electrodialysis Model with Zero Fitting Parameters: Insights into Process Limitations, Design, and Material Interventions

Redox-Electrodialysis (r-ED) is an electrochemical desalination cell architecture that has recently received considerable interest, due to its low energy demand relative to electrochemical desalination technologies that rely on electrode-based ion removal. To further improve the energy efficiency of r-ED, we developed a lumped mathematical model with no adjustable parameters to investigate the various sources of overpotential within the cell. Existing models of electrodialysis and r-ED cells either do not accurately incorporate all phenomena contributing to the overpotential or utilize empirical fitting parameters. The model developed here indicates that ohmic overpotentials, especially in the diluate chamber, are the most significant contributors to energy losses. Based on this insight, we hypothesized that adding an ion exchange resin wafer in the diluate compartment would increase the ionic conductivity and decrease the energy demand. Experimental results showed an 18% reduction in specific energy use while achieving the same degree of salt removal (20 mM to 12 mM). Furthermore, the resin wafer enabled complete desalination to potable drinking levels at a current density previously unachievable within practical operating voltage limits (4.93 mA cm−2). We also expanded the model to explore differences in r-ED energy use between configurations using multiple cells and a single cell with increased area.

Enhancing bio-photovoltaic cell efficiency: A study in transport property

Recently, bio-solar cells have garnered significant attention owing to their relatively high efficiency and cost-effectiveness, positioning them as alternative devices for solar energy harvesting. This study delves into the optical and electrical transport characteristics of a novel bilayer bio-solar cell using the total system transfer matrix method, theoretically. These bilayer bio-solar cells consist of two distinct layers of Chlorophyll-a and Chlorophyll-b, forming a heterojunction in the bio-solar cell architecture. Within these solar cells, photon absorption by the active layers of chlorophyll generates excitons and quasi-particles (bound electron and hole pairs), which subsequently diffuse through the collecting layer, resulting in significant recombination losses. The influence of the thickness of chlorophyll adsorbent active layers on the short circuit current density and quantum efficiency is examined through numerical calculations. Furthermore, we develop models for the solar cell parameters of thin film heterojunction photovoltaic devices based on Chlorophyll-a/Chlorophyll-b. The results indicate efficient short circuit current and quantum efficiency values (or power conversion efficiency) of 72 A/m2 and 3.30 %, respectively. It is demonstrated that optimizing the thickness of bio-solar cells based on these findings may enhance electron transport, leading to higher photocurrents and improved overall efficiency. These simulation outcomes pave the way for optimizing the thickness of bio-solar cells and advancing towards higher efficiencies.

Nuclear Rac1 controls nuclear architecture and cell migration of glioma cells

Rac1 (Ras-related C3 botulinum toxin substrate 1) protein has been found in the cell nucleus many years ago, however, its nuclear functions are still poorly characterized but some data suggest its nuclear accumulation in cancers. We investigated nuclear Rac1 in glioma cancer cells nuclei and compared its levels and activity to normal astrocytes, and also characterized the studied cells on various nuclear properties and cell migration patterns.Nuclear Rac1 indeed was found accumulated in glioma cells, but only a small percentage of the protein was in active, GTP-bound state in comparison to healthy control. Altering the nuclear activity of Rac1 influenced chromatin architecture and cell motility in GTP-dependent and independent manner. This suggests that the landscape of Rac1 nuclear interactions might be as complicated and wide as its well-known, non-nuclear signaling.

Electrochemical carbon monoxide reduction at high current density: Cell configuration matters

Electrochemical carbon monoxide reduction (COR) is an important link between the electrochemical CO2-to-CO reduction technology and the renewable production of C2+ chemicals. Along with the development of catalyst materials for selective and efficient COR, it is imperative to optimize electrolysis conditions and cell parameters to efficiently reduce CO at industrially relevant current density and produce concentrated product streams. This study focuses on understanding fundamental differences in reaction selectivity during COR, when the same Cu catalyst was used in three different cell configurations, namely, microfluidic, hybrid anode zero-gap, and zero-gap electrolysers. In all cases, ethylene, acetate, ethanol, and propanol formation was confirmed at industrially relevant current densities (0.5–1.2 A cm−2) at reasonable cell voltages, albeit with subtle differences. The local chemical environment at the electrode/electrolyte interface is very different in each configuration leading to different product distribution and product crossover to the anode. This stresses the importance of cell architecture and implies that comparing the catalytic activity of a catalyst studied with different cell configurations can lead to inconsistent conclusions.

Interdigitated‐back‐contacted silicon heterojunction solar cells featuring novel MoOx‐based contact stacks

AbstractThe fabrication process of interdigitated‐back‐contacted silicon heterojunction (IBC‐SHJ) solar cells has been significantly simplified with the development of the so‐called tunnel‐IBC architecture. This architecture utilizes a highly conductive (p)‐type nanocrystalline silicon (nc‐Si:H) layer deposited over the full substrate area comprising pre‐patterned (n)‐type nc‐Si:H fingers. In this context, the (p)‐type nc‐Si:H layer is referred to as blanket layer. As both electrodes are connected to the same blanket layer, the high lateral conductivity of (p)nc‐Si:H layer can potentially lead to relatively low shunt resistance in the device, thus limiting the performance of such solar cells. To overcome such limitation, we introduce a thin (<2 nm) full‐area molybdenum oxide (MoOx) layer as an alternative to the (p)nc‐Si:H blanket layer. We demonstrate that the use of such a thin MoOx minimizes the shunting losses thanks to its low lateral conductivity while preserving the simplified fabrication process. In this process, a novel (n)‐type nc‐Si:H/MoOx electron collection contact stack is implemented within the proposed solar cell architecture. We assess its transport mechanisms via electrical simulations showing that electron transport, unlike in the case of tunnel‐IBC, occurs in the conduction band fully. Moreover, the proposed contact stack is evaluated in terms of contact resistivity and integrated into a proof‐of‐concept front/back‐contacted (FBC) SHJ solar cells. Contact resistivity as low as 100 mΩcm2 is achieved, and fabricated FBC‐SHJ solar cells obtain a fill factor above 81.5% and open‐circuit voltage above 705 mV. Lastly, the IBC‐SHJ solar cells featuring the MoOx blanket layer are fabricated, exhibiting efficiencies up to 21.14% with high shunt resistances above 150 kΩcm2. Further optimizations in terms of layer properties and fabrication process are proposed to improve device performance and realize the efficiency potential of our novel IBC‐SHJ solar cell architecture.

Extensive long-range polycomb interactions and weak compartmentalization are hallmarks of human neuronal 3D genome.

Chromatin architecture regulates gene expression and shapes cellular identity, particularly in neuronal cells. Specifically, polycomb group (PcG) proteins enable establishment and maintenance of neuronal cell type by reorganizing chromatin into repressive domains that limit the expression of fate-determining genes and sustain distinct gene expression patterns in neurons. Here, we map the 3D genome architecture in neuronal and non-neuronal cells isolated from the Wernicke's area of four human brains and comprehensively analyze neuron-specific aspects of chromatin organization. We find that genome segregation into active and inactive compartments is greatly reduced in neurons compared to other brain cells. Furthermore, neuronal Hi-C maps reveal strong long-range interactions, forming a specific network of PcG-mediated contacts in neurons that is nearly absent in other brain cells. These interacting loci contain developmental transcription factors with repressed expression in neurons and other mature brain cells. But only in neurons, they are rich in bivalent promoters occupied by H3K4me3 histone modification together with H3K27me3, which points to a possible functional role of PcG contacts in neurons. Importantly, other layers of chromatin organization also exhibit a distinct structure in neurons, characterized by an increase in short-range interactions and a decrease in long-range ones.

Trophoblast stem cells, trophoblast invasion, and organoids - advancements in gynecology.

The human placenta serves as a vital barrier between the mother and the developing fetus during pregnancy. A defect in the early development of the placenta is associated with severe pregnancy disorders. Despite its complex development, various molecular processes control placental development, and the specialization of trophoblast cells is still not fully understood. One primary obstacle is the lack of suitable cell model systems. Traditional two-dimensional (2D) cell cultures fail to mimic in vivo conditions and do not capture the intricate intercellular interactions vital for studying placental development. However, three-dimensional (3D) organoid models derived from stem cells that replicate natural cell organization and architecture have greatly improved our understanding of trophoblast behavior and its medicinal applications. Organoids with relevant phenotypes provide a valuable platform to model both placental physiology and pathology, including the modeling of placental disorders. They hold great promise for personalized medicine, improved diagnostics, and the evaluation of pharmaceutical drug efficacy and safety. This article provides a concise overview of trophoblast stem cells, trophoblast invasion, and the evolving role of organoids in gynecology.

Spatiotemporal architecture of immune cells and cancer-associated fibroblasts in high-grade serous ovarian carcinoma.

High-grade serous ovarian carcinoma (HGSOC), the deadliest form of ovarian cancer, is typically diagnosed after it has metastasized and often relapses after standard-of-care platinum-based chemotherapy, likely due to advanced tumor stage, heterogeneity, and immune evasion and tumor-promoting signaling from the tumor microenvironment. To understand how spatial heterogeneity contributes to HGSOC progression and early relapse, we profiled an HGSOC tissue microarray of patient-matched longitudinal samples from 42 patients. We found spatial patterns associated with early relapse, including changes in T cell localization, malformed tertiary lymphoid structure (TLS)-like aggregates, and increased podoplanin-positive cancer-associated fibroblasts (CAFs). Using spatial features to compartmentalize the tissue, we found that plasma cells distribute in two different compartments associated with TLS-like aggregates and CAFs, and these distinct microenvironments may account for the conflicting reports about the role of plasma cells in HGSOC prognosis.

Exploring the potential of tin-based perovskite-silicon tandem solar cells through numerical analysis: A pathway to sustainable energy innovation

“Necessity is the mother of invention.” The global imperative to transition from fossil fuels to renewable energy sources, driven by the pressing issue of climate change, highlights the significance of advancing solar energy technologies. While single junction solar cells have reached a peak efficiency of approximately 31 %, the pursuit of higher efficiency has led to the exploration of tandem solar cell architectures, including perovskite-silicon and all-perovskite configurations. However, the widespread use of lead in perovskite structures raises environmental and health concerns. In response to these challenges, this study proposes a novel approach by integrating a tin-based wide bandgap absorber layer with a silicon HIT solar cell (Heterojunction with Intrinsic Layer). The investigation consists of an extensive exploration of six different carrier transport layers (CTL) for the top perovskite layer, considering variations in thickness and defect density. A comprehensive analysis of charge carrier dynamics within the device is conducted to understand the role of defect density in influencing solar cell performance parameters. Simulation results show that the overall tandem device gives an encouraging PCE of 32.12 % in 2 T configuration due to its excellent high value of current density matching 17.63 mA/cm2 and open-circuit voltage of 2.19V. We sincerely hope that our work will open new avenues in the field of Solar Photovoltaics paving the way for future innovations.

Numerical optimization of interface engineering parameters for a highly efficient HTL-free perovskite solar cell

Decarbonizing the world’s energy system has set the stage in favor of renewable energy alternatives such as the more reliable, abundant, inexhaustible, and sustainable solar energy. However, the photovoltaic technology faces significant stability, longevity, and scalability challenges. These difficulties can be overcome by judicious optimization of interfacial engineering of the solar cell architecture that will decrease the cost of fabrication and enhance the solar cell performance and durability. Herein, a comprehensive analysis of a novel high-performance hole transport layer-free (HTL-free) perovskite solar cell (PSC) of the configuration, ITO/PC61BM/CH3NH3SnI3/Pt, was investigated by device simulation while optimizing electron transport materials, metal back contacts, front contact materials, and buffer layers. The focus is on enhancing device performance by introducing various types of buffer layers, such as cadmium sulphide (CdS) in the proposed solar cell model. By fine-tuning the ETL layers and manipulating perovskite acceptor and donor densities, better device performance was achieved. Furthermore, the Mott-Schottky capacitance analysis yielded critical insights into the interface properties and dynamics of charge carriers within the solar cell structure. Optimizing back contacts also play a critical role in charge extraction and reduced recombination losses. Leveraging a sophisticated simulation platform, SCAPS-1D, the study assesses how design strategies impact photovoltaic electrical outcomes such as open-circuit voltage (Voc), power conversion efficiency (PCE), short-circuit current density (Jsc), and Fill factor (FF). The proposed HTL-free device posted remarkable results – PCE of 38.11 %, Jsc of 35.32 mAcm−2, FF of 88.67 %, and Voc of 1.2168 V. Accordingly, this work inspires the promising prospects of HTL-free PSCs in achieving robust solar harvesting capabilities while streamlining device affordability. Therefore, the proposed device architecture stimulates the journey towards affordable and high-performance scalable solar cell modules.

Nitrogen-fixing organelle in a marine alga.

Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Biological nitrogen fixation, the reduction of abundant atmospheric nitrogen gas (N2) to biologically available ammonia, is a key metabolic process performed exclusively by prokaryotes. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N2-fixing organelle, or "nitroplast."

Sheet Resistance Optimization in (Al)GaInP Solar Cells for Concentrator Quadruple–Junction Solar Cells

The reduction of the series resistance in multi‐junction solar cells is of high importance for attaining peak efficiencies in concentrator photovoltaics. This study showcases strategies to reduce the sheet resistance of the uppermost subcell of a direct wafer bonded four–junction devices, since it contributes significantly to the series resistance. Therefore, electron mobilities in n–type AlGaInP, lattice matched to GaAs, are investigated across bandgap energies between 1.9 eV and 2.1 eV and for various doping concentrations. The sheet resistances for AlGaInP rear heterojunction cells are determined for the integration in a two terminal four‐junction solar cell. The rear heterojunction cell architecture effectively addresses the sheet resistance optimization because it features a thick n‐type doped absorption layer. The sheet resistance of our current world record quadruple‐junction solar cell with 47.6% efficiency under the 665‐fold concentrated AM1.5d spectrum is 550 Ωsq–1. Here, we show how optimizing the n‐absorption layer in the 1.90 eV GaInP top cell can reduce the sheet resistance to 250 Ωsq–1 without deteriorating the short–circuit current density and current matching. This reduction corresponds to a 5 mΩcm2 improvement in specific series resistance, which would elevate the efficiency of this device to 48.2%.This article is protected by copyright. All rights reserved.