4,763 research outputs found
The production of charmonium pentaquark from b-baryon and B-meson decay: SU(3) analysis
In this paper, we study the production of charmonium pentaquark from bottom baryon and B-meson decays under the flavor SU(3) symmetry. Decay
amplitudes for various processes are parametrized in terms of the SU(3)
irreducible nonperturbative amplitudes. A number of relations between decay
widths have been deduced. Moreover, the strong decays of pentaquark is also
taken into account. These results can be tested in future measurements at LHCb,
Belle II and CEPC. Once a few decay branching fractions have been measured, our
work could provide hints for exploring new decay channels or new pentaquark
states.Comment: 10 pages,2 figure
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A regioselectivity switch in Pd-catalyzed hydroallylation of alkynes.
By exploiting the reactivity of a vinyl-Pd species, we control the regioselectivity in hydroallylation of alkynes under Pd-hydride catalysis. A monophosphine ligand and carboxylic acid combination promotes 1,5-dienes through a pathway involving isomerization of alkynes to allenes. In contrast, a bisphosphine ligand and copper cocatalyst favor 1,4-dienes via a mechanism that involves transmetalation. Our study highlights how to access different isomers by diverting a common organometallic intermediate
NExT-GPT: Any-to-Any Multimodal LLM
While recently Multimodal Large Language Models (MM-LLMs) have made exciting
strides, they mostly fall prey to the limitation of only input-side multimodal
understanding, without the ability to produce content in multiple modalities.
As we humans always perceive the world and communicate with people through
various modalities, developing any-to-any MM-LLMs capable of accepting and
delivering content in any modality becomes essential to human-level AI. To fill
the gap, we present an end-to-end general-purpose any-to-any MM-LLM system,
NExT-GPT. We connect an LLM with multimodal adaptors and different diffusion
decoders, enabling NExT-GPT to perceive inputs and generate outputs in
arbitrary combinations of text, images, videos, and audio. By leveraging the
existing well-trained highly-performing encoders and decoders, NExT-GPT is
tuned with only a small amount of parameter (1%) of certain projection layers,
which not only benefits low-cost training and also facilitates convenient
expansion to more potential modalities. Moreover, we introduce a
modality-switching instruction tuning (MosIT) and manually curate a
high-quality dataset for MosIT, based on which NExT-GPT is empowered with
complex cross-modal semantic understanding and content generation. Overall, our
research showcases the promising possibility of building an AI agent capable of
modeling universal modalities, paving the way for more human-like AI research
in the community. Project page: https://next-gpt.github.io/Comment: work in progres
Buccal Transmucosal Delivery System of Enalapril for Improved Cardiac Drug Delivery: Preparation and Characterization
Purpose: To prepare and characterize buccal transmucosal delivery system of enalapril maleate for overcoming its low bioavailability, and hence provide improved therapeutic efficacy and patient compliance.Methods: Transmucosal drug delivery systems of enalapril maleate were formulated as buccal films by solvent casting technique using polyvinylpyrrolidone K90, hydroxypropyl methylcellulose, sodium carboxymethylcellulose (high viscosity). The films were evaluated for film weight, thickness, folding endurance, drug content uniformity, surface pH, in vitro residence time, in vitro drug release and ex-vivo permeation.Results: All the formulations showed high drug content (96.45 to 98.49 %). Those with good swelling showed good residence time. In vitro drug release was highest for films prepared with high viscosity grade sodium carboxymethylcellulose (SCMC- HV,F2), releasing 92.24 % of drug in 1.5 h) followed by F4 (containing polyvinyl pyrrolidone K-90 1 % w/v and SCMC (HV) 1 % w/v). Ex-vivo drug permeation at the end of 10 h was 82.24 and 89.9 % for F2 and F4, respectively.Conclusion: Prompt drug release was obtained from the formulation (F2) containing SCMC 2 % w/v with 10 mg enalapril. However, on the basis of the highest swelling and residence time, and controlled drug release, formulation F4 (containing PVP K-90 and SCMC HV) would be suitable for the development of buccal film for effective therapy of cardiac diseases.Keywords: Cardiac disease, Transmucosal, Buccal films, Enalapril maleate, Drug release, Ex-vivo permeatio
Surface variation analysis of freeform optical systems over surface frequency bands for prescribed wavefront errors
The surface errors of freeform surfaces reflect the manufacturing
complexities and significantly impact the feasibility of processing designed
optical systems. With multiple degrees of freedom, freeform surfaces pose
challenges in surface tolerance analysis in the field. Nevertheless, current
research has neglected the influence of surface slopes on the directions of ray
propagation. A sudden alteration in the surface slope will lead to a
corresponding abrupt shift in the wavefront, even when the change in surface
sag is minimal. Moreover, within the realm of freeform surface manufacturing,
variation in surface slope across different frequency bands may give rise to
unique surface variation. Within the context of this study, we propose a
tolerance analysis method to analyze surface variation in freeform surfaces
considering surface frequency band slopes based on real ray data. This approach
utilizes real ray data to rapidly evaluate surface variation within a specified
frequency band of surface slopes. Crucially, our proposed method yields the
capability to obtain system surface variation with significant wavefront
aberration, in contrast to previous methodologies. The feasibility and
advantages of this framework are assessed by analyzing a single-mirror system
with a single field and an off-axis two-mirror system. We expect to integrate
the proposed methodology with freeform surface design and manufacturing,
thereby expanding the scope of freeform optics
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