Patterning Process Research Articles

Polymer-Free and Dry Patterning of Wafer-Scale Two-Dimensional Semiconductors via van der Waals Delamination.

Two-dimensional (2D) semiconductors have attracted a considerable amount of interest as channel materials for future transistors. Patterning of 2D semiconductors is crucial for separating continuous monolayers into independent units. However, the state-of-the-art 2D patterning process is largely based on photolithography and high-energy plasma/RIE etching, leading to unavoidable residues and degraded device uniformity, which remains a critical challenge for the practical application of 2D electronics. Here, we report a polymer-free and dry-patterning technique for wafer-scale 2D semiconductors. Upon lamination of a three-dimensional Au stamp onto monolayer MoS2 and then it being peeled away, the Au-contacted region will be effectively removed while the noncontacted regions are successfully left on its growth substrate. The fabricated MoS2 transistors exhibit a 100% device yield, increased carrier mobility, and much reduced device-to-device variation, compared to those of conventional wet-patterned devices. Our work provides a simple and rapid dry-patterning technique for 2D wafers, which is important for the lab-to-fab transition.

Dynamic changes and influential factors of blowouts in a desert artificial ecosystem at the southeastern margin of Tengger Desert in China.

The wind-blown sand protection system in the Shapotou section of the Baotou-Lanzhou Railway is a representative artificial ecosystem in a desert region. Over the past 70 years, this system has transformed mobile dunes into fixed dunes through vegetation succession, relying solely on natural rainfall without additional irrigation. However, ecosystem sustainability has been endangered by the emergence of numerous blowouts. Therefore, understanding the status and developmental trends of these blowouts is crucial for maintaining the system and ensuring railway safety. In this study, we quantitatively analyzed the number, spatial pattern, and evolution process of blowouts using a landscape pattern index and Spatial-Temporal Analysis of Moving Polygons (STAMP) model with remote sensing images from 2009 to 2022. Currently, blowout areas account for 1.57% of the total area with a clustered distribution. The number of blowouts increased significantly from 308 to 463 between 2009 and 2022 and increased with increasing distance from the railway line. Various evolutionary events have occurred among the blowouts, with peak frequencies in the generation and disappearance events observed by 2022. The average growth rate of blowouts was 7.32% in areas with less than 40 years of sand fixation but less than 1% in areas with more than 40 years, and mid-sized blowouts predominated the overall protection system. There was little difference between the blowout wind-erosion area and the fixed area in the natural environment. However, human activities can accelerate the evolution of blowouts, leading to more frequent contraction and expansion events and significantly increasing the area of wind erosion.

In Search of an Integrative Method to Study Unconscious Processing: An Application of Bayesian and General Recognition Theory Models to the Processing of Hierarchical Patterns in the Absence of Awareness.

The dissociation between conscious and unconscious perception is one of the most relevant issues in the study of human cognition. While there is evidence suggesting that some stimuli might be unconsciously processed up to its meaning (e.g., high-level stimulus processing), some authors claim that most results on the processing of subliminal stimuli can be explained by a mixture of methodological artefacts and questionable assumptions about what can be considered non-conscious. Particularly, one of the most controversial topics involves the method by which the awareness of the stimuli is assessed. To address this question, we introduced an integrative approach to assess the extent to which masked hierarchical stimuli (i.e., global shapes composed of local elements) can be processed in the absence of awareness. We combined a priming task where participants had to report global or local shapes, with the use of subjective and objective awareness measures collected either in a separate block (offline), or trial-by-trial during the main task (online). The unconscious processing of the masked primes was then evaluated through two different novel model-based methods: a Bayesian and a General Recognition Theory modeling approach. Despite the high correlation between awareness measures, our results show that the use of alternative approaches based on different theoretical assumptions leads to diverging conclusions about the extent of the unconscious processing of the masked primes.

The Turing heritage for plant biology: all spots and stripes?

Abstract In ‘The chemical basis of morphogenesis’ (1952), Alan Turing introduced an idea that revolutionised our thinking about pattern formation. He proposed that diffusion could lead to the spontaneous formation of regular patterns. Here, we discuss the impact of Turing’s idea on plant science using three well-established examples at different scales: ROP patterning inside single cells, epidermal patterning across several cells and whole vegetation patterns. Also at intermediate levels, e.g., organ spacing, plants look surprisingly regular. But not all regular patterns are Turing patterns, careful observation and prediction of the patterning process—not just the final pattern—is critical to distinguish between mechanisms.

Deep conservation complemented by novelty and innovation in the insect eye ground plan

A spectacular diversity of forms and features allow species to thrive in different environments, yet some structures remain relatively unchanged. Insect compound eyes are easily recognizable despite dramatic differences in visual abilities across species. It is unknown whether distant insect species use similar or different mechanisms to pattern their eyes or what types of genetic changes produce diversity of form and function. We find that flies, mosquitos, butterflies, moths, beetles, wasps, honeybees, and crickets use homologous developmental programs to pattern their retinas. Transcription factor expression can be used to establish homology of different photoreceptor (PR) types across the insects: Prospero (Pros) for R7, Spalt (Sal) for R7+R8, and Defective proventriculus (Dve) for R1-6. Using gene knockout (CRISPR/Cas9) in houseflies, butterflies, and crickets and gene knockdown (RNAi) in beetles, we found that like Drosophila, EGFR and Sevenless (Sev) signaling pathways are required to recruit motion and color vision PRs, though Drosophila have a decreased reliance on Sev signaling relative to other insects. Despite morphological and physiological variation across species, retina development passes through a highly conserved phylotypic stage when the unit eyes (ommatidia) are first patterned. This patterning process likely represents an "insect eye ground plan" that is established by an ancient developmental program. We identify three types of developmental patterning modifications (ground plan modification, nonstochastic patterns, and specialized regions) that allow for the diversification of insect eyes. We suggest that developmental divergence after the ground plan is established is responsible for the exceptional diversity observed across insect visual systems.

Time-Course Strategy Reveals a Dual Potential of Perfluorooctanoic Acid and Its Alternative in Adipocyte Differentiation.

Exposure to perfluorooctanoic acid (PFOA) and hexafluoropropylene oxide dimer acid (HFPO-DA) was associated with adipogenesis. However, potential mechanisms remain to be elucidated. Herein, a 3T3-L1 adipocyte model was used to explore the dynamic changes in adipocyte differentiation (2, 4, and 8 days) under PFOA and HFPO-DA exposure. PFOA and HFPO-DA increased the adipocyte formation rate and intracellular levels of triglycerides (TG). Meanwhile, adipocyte browning was induced by PFOA and HFPO-DA, which was characterized by small lipid droplets, low levels of TG per adipocyte, increased ATP levels, and elevated mitochondrial respiration activities with time-dependent differentiation. The browning potency indexes of PFOA and HFPO-DA were approximately 1.5 times higher than those of the controls. Time-course transcriptomics analysis showed that PFOA and HFPO-DA activated the biological process of adipocyte browning but different gene expression patterns regulated adipocyte browning. Only overexpressed hydroxymethylglutaryl-CoA synthase (Hmgcs2) was shared between PFOA and HFPO-DA groups from 2 to 8 days. Hmgcs2 could regulate adipocyte browning induced by PFOA and HFPO-DA, and this observation was lost when Hmgcs2 was knocked down. Our study suggests that PFOA and HFPO-DA could play dual roles in the differentiation of 3T3-L1 adipocytes, and Hmgcs2 might be a target of PFOA- and HFPO-DA-induced adipocyte browning.

Single-electron charge sensor self-aligned to a quantum dot array by double-gate patterning process

Abstract The high sensitivity of a single electron transistor (SET) is essential to faithfully identify the number of electrons in a quantum dot (QD) towards a silicon-based quantum computer. The sensitivity depends on the critical dimension between the SET and the QD, which is limited by the resolution of the electron beam lithography and the layer-to-layer alignment accuracy. Here, we report integration of an SET charge sensor with a QD array by repeating the self-aligned double-gate patterning processes. This fabrication technique allowed us to place the SET adjacent to the QD array beyond the lithography resolution, enabling sensitive charge sensing. We confirm that our device can detect single electrons in the QD and demonstrate real-time detections of electron tunneling by monitoring the SET current.

Land Use Challenges in Emerging Economic Corridors of the Global South: A Case Study of the Laos Economic Corridor

Economic corridors play a crucial role in promoting economic growth and facilitating coordinated regional development. However, land use changes associated with the development of emerging economic corridors have become a prominent source of conflict in regional integration in the Global South. This study takes the Laos Economic Corridor as a case study to explore the characteristics and driving mechanisms of land use changes in emerging economic corridor regions. Using global land cover data from 2000 to 2020 (GlobeLand30) and employing spatial statistical analysis, the Random Forest (RFC) algorithm, and the CA-Markov model, the study follows a Pattern–Process–Mechanism–Trend analytical framework to reveal the spatial distribution characteristics and transformation paths of land use within the corridor. The study results indicate that (1) The land use pattern in the Laos Economic Corridor has gradually shifted from a “single-core radial” structure to a “dumbbell-shaped” structure, promoting coordinated regional economic development. (2) A significant unidirectional flow of land use has been established, with forestland being converted into cultivated land and cultivated land being further converted into artificial surfaces. (3) In addition to the natural geographical constraints, the transport infrastructure and the spatial layout of industries are the main drivers for the expansion of ecological land, agricultural land, and built-up land. (4) Spatial planning interventions are essential and urgent: the establishment of land management rules based on the principles of forest conservation and intensive development can effectively control the uncontrolled expansion of artificial areas, significantly reduce the loss of forestland, and ensure the rational allocation of land resources for long-term development. The findings of this study offer valuable insights and reference points for the Global South, enhancing understanding of the spatial development dynamics of economic corridors, informing the optimization of land-use policies, and supporting efforts to promote regional integration and sustainable development.

Does cognitive inhibition contribute to working memory and reasoning during childhood?

Theoretical frameworks suggest that cognitive inhibition suppresses irrelevant information in working memory, preventing overload and promoting the processing of task-relevant information. Consequently, it may also contribute to more complex skills, such as abstract reasoning, by facilitating the retention and processing of patterns and relationships. However, empirical evidence does not consistently show these relationships in early elementary school years. This study aims to examine the validity of the following theoretical proposition: cognitive inhibition is a fundamental process that influences working memory, and both contribute to abstract reasoning in children aged 6-8years. The final sample included 293 schoolchildren from 1st, 2nd, and 3rd grades, who completed tasks measuring cognitive inhibition, working memory, and reasoning. Age was also considered in the analyses. The main results indicate that age is associated with improvements in working memory and reasoning (explaining 19% of the variance), but not with cognitive inhibition performance. Additionally, cognitive inhibition directly contributes to working memory (explaining 19% of the variance), and working memory, but not cognitive inhibition, contributes to abstract reasoning (the model explains 23% of the variance). No indirect effects were found. We discuss the importance of incorporating specific relationships between cognitive skills at different developmental stages into theoretical and practical proposals.

R-DeeP/TripepSVM identifies the RNA-binding OB-fold-like protein PatR as regulator of heterocyst patterning.

RNA-binding proteins (RBPs) are central components of gene regulatory networks. The differentiation of heterocysts in filamentous cyanobacteria is an example of cell differentiation in prokaryotes. Although multiple non-coding transcripts are involved in this process, no RBPs have been implicated thus far. Here we used quantitative mass spectrometry to analyze the differential fractionation of RNA-protein complexes after RNase treatment in density gradients yielding 333 RNA-associated proteins, while a bioinformatic prediction yielded 311 RBP candidates in Nostoc sp. PCC 7120. We validated in vivo the RNA-binding capacity of six RBP candidates. Some participate in essential physiological aspects, such as photosynthesis (Alr2890), thylakoid biogenesis (Vipp1) or heterocyst differentiation (PrpA, PatU3), but their association with RNA was unknown. Validated RBPs Asl3888 and Alr1700 were not previously characterized. Alr1700 is an RBP with two oligonucleotide/oligosaccharide-binding (OB)-fold-like domains that is differentially expressed in heterocysts and interacts with non-coding regulatory RNAs. Deletion of alr1700 led to complete deregulation of the cell differentiation process, a striking increase in the number of heterocyst-like cells, and was ultimately lethal in the absence of combined nitrogen. These observations characterize this RBP as a master regulator of the heterocyst patterning and differentiation process, leading us to rename Alr1700 to PatR.

Molecular-scale kinetic Monte Carlo simulation of pattern formation in photoresist materials for EUV nanolithography

A kinetic Monte Carlo (KMC) simulation tool for modeling the pattern formation process in photoresist materials for extreme ultraviolet (photon energy 92 eV) nanolithography is presented. The availability of such a tool should support the progress toward novel materials and experimental procedures that lead to an improved pattern resolution. The molecular-scale simulations describe the process in a stochastic and mechanistic manner and include the excitation of high-energy electrons upon light absorption, the creation of a charged-particle cloud, electron-induced chemical degradation of the photoresist molecules, the resulting bond formation between neighboring degraded molecules, and a chemical development step after which a pattern of the remaining non-dissolved molecules is obtained. The method is applied to the application-relevant class of Sn-oxocore photoresist materials and uses their known electronic structure and optical electron energy loss function. The validity of the approach is tested by comparing measured and simulated total electron yield spectra and photoelectron spectra. A demonstration of the method is given by calculating the dose and pitch dependent average shape and stochastic variability (line edge roughness) of line patterns that are obtained for rectangular and sine-wave illumination, assuming various scenarios that determine how molecular-scale degradation will lead to bond creation. We show how from these simulations the ultimate pattern resolution can be deduced. The findings are analyzed systematically using results of KMC simulations that reveal the size of the cloud of degraded molecules around a point of absorption (blur length) and that further reveal the sensitivity to uniform illumination (contrast curves), and using percolation theory. We find that KMC modeling captures the consequences of the strong gradients in the density of degraded molecules and of the stochasticity of the patterning process that simplified models do not include, leading to a significantly improved view of the final pattern quality.

Cell Architecture and Dynamics of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes (hiPSC-CMs) on Hydrogels with Spatially Patterned Laminin and N-Cadherin.

Controlling cellular shape with micropatterning extracellular matrix (ECM) proteins on hydrogels has been shown to improve the reproducibility of the cell structure, enhancing our ability to collect statistics on single-cell behaviors. Patterning methods have advanced efforts in developing human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as a promising human model for studies of the heart structure, function, and disease. Patterned single hiPSC-CMs have exhibited phenotypes closer to mature, primary CMs across several metrics, including sarcomere alignment and contractility, area and aspect ratio, and force production. Micropatterning of hiPSC-CM pairs has shown further improvement of hiPSC-CM contractility compared to patterning single cells, suggesting that CM-CM interactions improve hiPSC-CM function. However, whether patterning single hiPSC-CMs on a protein associated with CM-CM adhesion, like N-cadherin, can drive similar enhancement of the hiPSC-CM structure and function has not been tested. To address this, we developed a novel dual-protein patterning process featuring covalent binding of proteins at the hydrogel surface to ensure robust force transfer and force sensing. The patterns comprised rectangular laminin islands for attachment across the majority of the cell area, with N-cadherin "end caps" to imitate CM-CM adherens junctions. We used this method to geometrically control single-cell CMs on deformable hydrogels suitable for traction force microscopy (TFM) to observe cellular dynamics. We seeded α-actinin::GFP-tagged hiPSC-CMs on dual-protein patterned hydrogels and verified the interaction between hiPSC-CMs and N-cadherin end caps via immunofluorescent staining. We found that hiPSC-CMs on dual-protein patterns exhibited higher cell area and contractility in the direction of sarcomere organization than those on laminin-only patterns but no difference in sarcomere organization or total force production. This work demonstrates a method for covalent patterning of multiple proteins on polyacrylamide hydrogels for mechanobiological studies. However, we conclude that N-cadherin only modestly improves single-cell patterned hiPSC-CM models and is not sufficient to elicit increases in contractility observed in hiPSC-CM pairs.

Selectively Self-Aligned Sol-Gel Copper Oxide for Large-Area Multi-Valued Logic Devices.

Rapid expansion of digital information density has led to a growing demand for multi-valued logic (MVL) systems, which aim to minimize energy and time consumption for computations. Heterojunction transistors represent a class of device architectures for MVL circuits; however, partially layered structures can be realized only for vacuum-deposited organic and transferred 2D materials due to the constraints of patterning processes. In this study, a novel CuxO/IGZO heterojunction-based ternary inverter is presented via a sol-gel technique and direct patterning process using a self-assembled monolayer (SAM). This approach allows for a promising alternative to conventional photolithography, with the electrical characteristics of SAM-processed oxide thin-film transistors closely matching those of pristine devices. Structural investigations validate the partially overlapped heterojunction and its smoothness. Depth profiling with x-ray photoelectronspectroscopy highlights an oxidation gradient in CuxO, suggesting enhanced hole introduction at the IGZO interface. This mechanism potentially supports efficient hole transport and negative differential transconductance, foundational for MVL systems. Such advancements signify the potential for solution-processable digital electronics that offer streamlined fabrication at an affordable budget.

Bilateral cellular flows display asymmetry prior to left-right organizer formation in amniote gastrulation.

Bilaterians are defined by a bilaterally symmetrical body plan. Vertebrates exhibit external bilateral symmetry but display left-right (LR) asymmetry in their internal organs. Amniote embryos switch the patterning of internal organs from bilateral symmetry to LR-asymmetry. Using chick embryos as a model system, here we examined the initiation of LR symmetry breaking. Our biophysical approaches to quantify cellular flows inferred that LR symmetry breaking occurs before the formation of Hensen's node, a LR organizer, which serves as a signaling center for LR patterning-gene programs. Our work demonstrates that quantitative biophysical parameters can help unravel the initiation of LR symmetry breaking, suggesting an involvement of physical mechanisms in this critical biological patterning process.

Convergence of autism proteins at the cilium.

Hundreds of high confidence autism genes have been identified, yet the relevant etiological mechanisms remain unclear. Gene ontology analyses have repeatedly identified enrichment of proteins with annotated functions in gene expression regulation and neuronal communication. However, proteins are often pleiotropic and these annotations are inherently incomplete. Our recent autism functional genetics work has suggested that these genes may share a common mechanism at the cilium, a membrane-bound organelle critical for neurogenesis, brain patterning, and neuronal activity-all processes strongly implicated in autism. Moreover, autism commonly co-occurs with conditions that are known to involve ciliary-related pathologies, including congenital heart disease, hydrocephalus, and blindness. However, the role of autism genes at the cilium has not been systematically investigated. Here we demonstrate that autism proteins spanning disparate functional annotations converge in expression, localization, and function at cilia, and that patients with pathogenic variants in these genes have cilia-related co-occurring conditions and biomarkers of disrupted ciliary function. This degree of convergence among genes spanning diverse functional annotations strongly suggests that cilia are relevant to autism, as well as to commonly co-occurring conditions, and that this organelle should be explored further for therapeutic potential.

New Approaches to Determining the D/H Ratio in Aqueous Media Based on Diffuse Laser Light Scattering for Promising Application in Deuterium-Depleted Water Analysis in Antitumor Therapy

The development of affordable and reliable methods for quantitative determination of stable atomic nuclei in aqueous solutions and adjuvant agents used in tumor chemotherapy is an important task in modern pharmaceutical chemistry. This work quantified the deuterium/prothium isotope ratio in aqueous solutions through an original two-dimensional diffuse laser scattering (2D-DLS) software and hardware system based on chemometric processing of discrete interference patterns (dynamic speckle patterns). For this purpose, 10 mathematical descriptors (di), similar to QSAR descriptors, were used. Correlation analysis of bivariate “log di—D/H” plots shows an individual set of multi-descriptors for a given sample with a given D/H ratio (ppm). A diagnostic sign (DS) of differentiation was established: the samples were considered homeomorphic if 6 out of 10 descriptors differed by less than 15% (n ≥ 180). The analytical range (r = 0.987) between the upper (D/H ≤ 2 ppm) and lower (D/H = 180 ppm) limits for the quantification of stable hydrogen nuclei in water and aqueous solutions were established. Using the Spirotox method, a «safe zone» for protozoan survival was determined between 50 and 130 ppm D/H. Here, we discuss the dispersive (DLS, LALLS) and optical properties (refractive index, optical rotation angle) of the solutions with different D/H ratios that define the diffuse laser radiation due to surface density inhomogeneities. The obtained findings may pave the way for the future use of a portable, in situ diffuse laser light scattering instrument to determine deuterium in water and aqueous adjuvants.

Dry resist laser patterning of flexible neural probes with fluidic functionality

Abstract Optogenetics enables insights into the development of neural diseases. Custom-designed neural probes are necessary to access targeted brain regions. Multifunctional and mechanically flexible probes with minimal footprint, comprising fluidic channels for drug delivery, light sources for optical stimulation, and micro electrodes for electro-physiological readout are beneficial due to reduced tissue trauma and consequently increased long-term stability. This study introduces a mechanically compliant neural probe that provides microfluidic channels and electrodes arranged close to fluidic outlet ports. The key challenge is to open the fluidic inlet and outlet ports avoiding potential channel clogging. A novel laserbased patterning process is demonstrated using a 248 nm KrF excimer laser. It offers high design flexibility in positioning the fluidic ports along the fluidic channels, as well their contamination-free opening under dry conditions. The laser patterning process applies reflective metal layers inside the fluidic channels, confining the laser ablation to the channel cover, thus minimizing potential damage of the channel substrate. Based on its high reflectivity and correspondingly low absorption and transmission at the applied laser wavelength, aluminium is determined to be the best choice for this protective layer.

Examining hazard-induced mobility patterns and decision-making in a space-time context using large-scale mobile phone data

Understanding human movements and how they relate to varied environmental risks is crucial as mobility is one of the most effective adaptation strategies to the hazards. To this end, this study examines the decision-making process of hazard-induced mobility patterns in a space−time context by investigating the space−time choices for avoiding the harmful impacts of air pollution and extreme cold events that are actualized into overt movement behaviors. Results suggest that people change their mobility patterns to avoid the harmful impacts of air pollution and cold events, and are less likely to move from less urbanized areas to highly urbanized areas to avoid the hazards, especially for air pollution. Furthermore, intercity and intracity movements can both be changed to avoid the harmful impacts of two hazards. This study finds that averting travel decisions are most sensitive to the origin's air quality on the day of travel and destination's extreme cold temperatures around one day ago and one day forecast. Our results offer fresh evidence on the decision-making mechanisms of mobility responses to air pollution and cold events.

Data-driven macro-scale simulation for rapid electrolyte wetting in lithium-ion batteries

The electrolyte wetting process in lithium-ion battery manufacturing is a critical part of processes that affects battery performance and productivity. However, it is difficult to accurately measure and optimise this process with existing technologies. In this study, a three-dimensional macroscopic filling and wetting simulation model based on actual battery material parameters is constructed, which can simulate the wetting process of electrolyte in porous electrodes and separators. The model is employed to analyse effects of filling pressure pattern, boundary conditions and other process parameters on the wetting rate. The results demonstrate that the use of multilateral cyclic pressure filling can optimise the electrolyte wetting, which is in accordance with industry practice. Consequently, the study proceeds to investigate potential process optimisation strategies, including electrolyte selection and ambient temperature. These findings not only address limitations of traditional models, which employ simplified parameters, but also present a novel approach to enhance manufacturing efficiency and reduce cost of lithium batteries. This is of paramount importance for the sustainable development of lithium-ion battery industry.

In Situ Asymmetric Patterning for Information Encryption

AbstractHere, Ag nanoparticle asymmetric assembly arrays (NAAAs) are realized through a facile and inexpensive in situ asymmetric patterning process based on plasmonic nanochemistry. The growth of Ag NPs follows the asymmetric maximum plasmonic field region of Au nanoholes under light irradiation, as demonstrated by finite‐difference time‐domain (FDTD) simulations. Ag NAAAs exhibit unique Fano resonance modes due to the asymmetric arrangement of the nanoparticles. The size and morphology of Ag NAAAs can be systematically tuned by adjusting the reaction duration, deposition parameters, and etching conditions. Various multiscale patterns from macroscopic to submicron scales can be precisely obtained in combination with photolithography. Ag NAAAs can serve as excellent surface‐enhanced Raman scattering (SERS) substrates with an enhancement factor of up to 2.79×109. Combining the adjustable asymmetric morphology and editable patterning capabilities of multiscale Ag NAAAs, the application of anti‐counterfeiting labels integrating structural, molecular, and pattern/text information is realized. In addition, asymmetric patterning techniques can be used to create Au NAAAs and applied on flexible polydimethylsiloxane substrates, thereby enhancing the versatility of the anti‐counterfeiting labels in practical applications.