125 research outputs found
Mannan-binding lectin regulates dendritic cell maturation and cytokine production induced by lipopolysaccharide
Significantly Enhanced Thermoelectric Performance of γ-In2Se3 through Lithiation via Chemical Diffusion
γ-In2Se3 is selected as a thermoelectric candidate because it has a unique crystal structure and thermal stability at relatively high temperatures. In this work we have prepared lithiated γ-In2Se3 through chemical diffusion and investigated its band structures and thermoelectric performance. After lithiation of γ-In2Se3 in lithium acetate (CH3COOLi) solution at 50oC, we have observed a high Hall carrier concentration (nH) up to ≤1.71×1018 cm-3 at room temperature (RT), which is about ∼4 orders of magnitude compared to that of pristine γ-In2Se3. The enhancement in nH is directly responsible for the remarkable improvement in electrical conductivity, and can be elucidated as the Fermi level (Fr) unpinning and moving towards the conduction band (CB) through the dominant interstitial occupation of Li+ in the γ-In2Se3 lattice. Combined with the minimum lattice thermal conductivity (κL=0.30-0.34 WK-1m-1) at ~923 K, the highest ZT value of 0.62-0.67 is attained, which is about 9-10 times that of pristine γ-In2Se3, proving that the lithiation in γ-In2Se3 is an effective approach on the improvement of the thermoelectric performance
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High-Speed Photothermal Patterning of Doped Polymer Films.
Organic semiconductors (OSCs) offer a new avenue to the next-generation electronics, but the lack of a scalable and inexpensive nanoscale patterning/deposition technique still limits their use in electronic applications. Recently, a new lithographic etching technique has been introduced that uses molecular dopants to reduce semiconducting polymer solubility in solvents and a direct-write laser to remove dopants locally, enabling rapid OSC etching with diffraction limited resolution. Previous publications postulated that the reaction that enables patterning is a photochemical reaction between photoexcited dopants with neutral solvent molecules. In this work, we analyze the photoinduced dissolution kinetics of F4TCNQ doped P3HT films using time-resolved in situ optical probing. We find two competing mechanisms that control de-doping and dissolution: the first is the photochemical reaction posited in the literature, and the second involves direct heating of the polymer by the laser, inducing increased solubility for both the polymer and dopant. We show that the wavelength-specific photochemical effect is dominant in low photon doses while the photothermal effect is dominant with high excitation rates regardless of laser wavelength. With sufficiently high optical intensity input, the photothermal mechanism can in principle achieve a high writing speed up to 1 m/s. Our findings bring new insights into the mechanisms behind laser direct writing of OSCs based on dopant induced solubility control and enable ultraprecise fabrications of various device configurations in large-scale manufacturing
MediViSTA-SAM: Zero-shot Medical Video Analysis with Spatio-temporal SAM Adaptation
In recent years, the Segmentation Anything Model (SAM) has attracted
considerable attention as a foundational model well-known for its robust
generalization capabilities across various downstream tasks. However, SAM does
not exhibit satisfactory performance in the realm of medical image analysis. In
this study, we introduce the first study on adapting SAM on video segmentation,
called MediViSTA-SAM, a novel approach designed for medical video segmentation.
Given video data, MediViSTA, spatio-temporal adapter captures long and short
range temporal attention with cross-frame attention mechanism effectively
constraining it to consider the immediately preceding video frame as a
reference, while also considering spatial information effectively.
Additionally, it incorporates multi-scale fusion by employing a U-shaped
encoder and a modified mask decoder to handle objects of varying sizes. To
evaluate our approach, extensive experiments were conducted using
state-of-the-art (SOTA) methods, assessing its generalization abilities on
multi-vendor in-house echocardiography datasets. The results highlight the
accuracy and effectiveness of our network in medical video segmentation
Transformation vs Tradition: Artificial General Intelligence (AGI) for Arts and Humanities
Recent advances in artificial general intelligence (AGI), particularly large
language models and creative image generation systems have demonstrated
impressive capabilities on diverse tasks spanning the arts and humanities.
However, the swift evolution of AGI has also raised critical questions about
its responsible deployment in these culturally significant domains
traditionally seen as profoundly human. This paper provides a comprehensive
analysis of the applications and implications of AGI for text, graphics, audio,
and video pertaining to arts and the humanities. We survey cutting-edge systems
and their usage in areas ranging from poetry to history, marketing to film, and
communication to classical art. We outline substantial concerns pertaining to
factuality, toxicity, biases, and public safety in AGI systems, and propose
mitigation strategies. The paper argues for multi-stakeholder collaboration to
ensure AGI promotes creativity, knowledge, and cultural values without
undermining truth or human dignity. Our timely contribution summarizes a
rapidly developing field, highlighting promising directions while advocating
for responsible progress centering on human flourishing. The analysis lays the
groundwork for further research on aligning AGI's technological capacities with
enduring social goods
Experimental demonstration of a free space cylindrical cloak without superluminal propagation
We experimentally demonstrated an alternative approach of invisibility
cloaking that can combine technical advantages of all current major cloaking
strategies in a unified manner and thus can solve bottlenecks of individual
strategies. A broadband cylindrical invisibility cloak in free space is
designed based on scattering cancellation (the approach of previous plasmonic
cloaking), and implemented with anisotropic metamaterials (a fundamental
property of singular-transformation cloaks). Particularly, non-superluminal
propagation of electromagnetic waves, a superior advantage of
non-Euclidian-transformation cloaks constructed with complex branch cuts, is
inherited in this design, and thus is the reason of its relatively broad
bandwidth. This demonstration provides the possibility for future practical
implementation of cloaking devices at large scales in free space.Comment: 16 pages, 3 figures, accepted by Physical Review Letter
High photocatalytic activity of Cu2O embedded in hierarchically hollow SiO2 for efficient chemoselective hydrogenation of nitroarenes
Photocatalytic organic conversion is a crucial process in the hydrogenation of nitroarenes, but harsh reaction conditions such as long reaction time, high hydrogen pressure, and organic medium still need to be considerably overcome under visible-light irradiation. Here, we have constructed a transition metal oxide photocatalyst by embedding low-cost Cu2O with strong visible-light absorption into hierarchically hollow SiO2 sphere (SiO2-Cu2O@SiO2) that can suppress the escape of photogenerated atomic hydrogen and promote the contact probability between hydrogen atom and nitroarene molecules due to confinement effect. Remarkably, the SiO2-Cu2O@SiO2 photocatalyst can exhibit efficient chemoselectivity toward the hydrogenation of various nitroarenes in an aqueous system at ambient conditions, successfully working out the requirement of strict hydrogenation conditions, especially for organic medium over almost all of the reported photocatalysts. Notably, quantitative aniline can be produced for the visible-light catalytic reduction of nitroarenes, suggesting a considerable potential for industrial applicatio
PharmacyGPT: The AI Pharmacist
In this study, we introduce PharmacyGPT, a novel framework to assess the
capabilities of large language models (LLMs) such as ChatGPT and GPT-4 in
emulating the role of clinical pharmacists. Our methodology encompasses the
utilization of LLMs to generate comprehensible patient clusters, formulate
medication plans, and forecast patient outcomes. We conduct our investigation
using real data acquired from the intensive care unit (ICU) at the University
of North Carolina Chapel Hill (UNC) Hospital. Our analysis offers valuable
insights into the potential applications and limitations of LLMs in the field
of clinical pharmacy, with implications for both patient care and the
development of future AI-driven healthcare solutions. By evaluating the
performance of PharmacyGPT, we aim to contribute to the ongoing discourse
surrounding the integration of artificial intelligence in healthcare settings,
ultimately promoting the responsible and efficacious use of such technologies
MA-SAM: Modality-agnostic SAM Adaptation for 3D Medical Image Segmentation
The Segment Anything Model (SAM), a foundation model for general image
segmentation, has demonstrated impressive zero-shot performance across numerous
natural image segmentation tasks. However, SAM's performance significantly
declines when applied to medical images, primarily due to the substantial
disparity between natural and medical image domains. To effectively adapt SAM
to medical images, it is important to incorporate critical third-dimensional
information, i.e., volumetric or temporal knowledge, during fine-tuning.
Simultaneously, we aim to harness SAM's pre-trained weights within its original
2D backbone to the fullest extent. In this paper, we introduce a
modality-agnostic SAM adaptation framework, named as MA-SAM, that is applicable
to various volumetric and video medical data. Our method roots in the
parameter-efficient fine-tuning strategy to update only a small portion of
weight increments while preserving the majority of SAM's pre-trained weights.
By injecting a series of 3D adapters into the transformer blocks of the image
encoder, our method enables the pre-trained 2D backbone to extract
third-dimensional information from input data. The effectiveness of our method
has been comprehensively evaluated on four medical image segmentation tasks, by
using 10 public datasets across CT, MRI, and surgical video data. Remarkably,
without using any prompt, our method consistently outperforms various
state-of-the-art 3D approaches, surpassing nnU-Net by 0.9%, 2.6%, and 9.9% in
Dice for CT multi-organ segmentation, MRI prostate segmentation, and surgical
scene segmentation respectively. Our model also demonstrates strong
generalization, and excels in challenging tumor segmentation when prompts are
used. Our code is available at: https://github.com/cchen-cc/MA-SAM
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