Antioxidant Activities of Plumbagin and Its Cu (II) Complex

Plumbagin and its Cu (II) complex [Cu (plumbagin)2]·H2O have been synthesized, and their antioxidant activities towards the inhibitory effect on DPPH free radical, reducing power, total antioxidant capacity, and inhibition on lipid peroxidation were investigated. Plumbagin and its Cu (II) complex were found to exhibit scavenging activities on DPPH radical with the inhibitory rate of 41% and 24%, respectively. The reducing power of plumbagin was outstanding at the concentrations of 1.0, 1.5, and 2.0 mg/mL, compared to Cu (II) complex and synthetic antioxidant 2,6-di-ter-butyl-4-methylphenol (BHT); the highest level reached 1.333 for plumbagin and 0.581 for Cu (II) complex. Also, the inhibition on lipid peroxidation of plumbagin was higher than that of Cu (II) complex and BHT, 46.4% for plumbagin and 24.5% for Cu (II) complex. The results give a strong impact for designing anticancer drugs, combined with their potential cytotoxic and antioxidant activities, which can be targeted selectively against cancer cells and increase their therapeutic index and additional advantages over other anticancer drugs

Large Language Model Can Interpret Latent Space of Sequential Recommender

Sequential recommendation is to predict the next item of interest for a user, based on her/his interaction history with previous items. In conventional sequential recommenders, a common approach is to model item sequences using discrete IDs, learning representations that encode sequential behaviors and reflect user preferences. Inspired by recent success in empowering large language models (LLMs) to understand and reason over diverse modality data (e.g., image, audio, 3D points), a compelling research question arises: ``Can LLMs understand and work with hidden representations from ID-based sequential recommenders?''.To answer this, we propose a simple framework, RecInterpreter, which examines the capacity of open-source LLMs to decipher the representation space of sequential recommenders. Specifically, with the multimodal pairs (\ie representations of interaction sequence and text narrations), RecInterpreter first uses a lightweight adapter to map the representations into the token embedding space of the LLM. Subsequently, it constructs a sequence-recovery prompt that encourages the LLM to generate textual descriptions for items within the interaction sequence. Taking a step further, we propose a sequence-residual prompt instead, which guides the LLM in identifying the residual item by contrasting the representations before and after integrating this residual into the existing sequence. Empirical results showcase that our RecInterpreter enhances the exemplar LLM, LLaMA, to understand hidden representations from ID-based sequential recommenders, especially when guided by our sequence-residual prompts. Furthermore, RecInterpreter enables LLaMA to instantiate the oracle items generated by generative recommenders like DreamRec, concreting the item a user would ideally like to interact with next. Codes are available at https://github.com/YangZhengyi98/RecInterpreter

A Bi-Step Grounding Paradigm for Large Language Models in Recommendation Systems

As the focus on Large Language Models (LLMs) in the field of recommendation intensifies, the optimization of LLMs for recommendation purposes (referred to as LLM4Rec) assumes a crucial role in augmenting their effectiveness in providing recommendations. However, existing approaches for LLM4Rec often assess performance using restricted sets of candidates, which may not accurately reflect the models' overall ranking capabilities. In this paper, our objective is to investigate the comprehensive ranking capacity of LLMs and propose a two-step grounding framework known as BIGRec (Bi-step Grounding Paradigm for Recommendation). It initially grounds LLMs to the recommendation space by fine-tuning them to generate meaningful tokens for items and subsequently identifies appropriate actual items that correspond to the generated tokens. By conducting extensive experiments on two datasets, we substantiate the superior performance, capacity for handling few-shot scenarios, and versatility across multiple domains exhibited by BIGRec. Furthermore, we observe that the marginal benefits derived from increasing the quantity of training samples are modest for BIGRec, implying that LLMs possess the limited capability to assimilate statistical information, such as popularity and collaborative filtering, due to their robust semantic priors. These findings also underline the efficacy of integrating diverse statistical information into the LLM4Rec framework, thereby pointing towards a potential avenue for future research. Our code and data are available at https://github.com/SAI990323/Grounding4Rec.Comment: 17 page

The Legionella pneumophila Effector SidJ Is Required for Efficient Recruitment of Endoplasmic Reticulum Proteins to the Bacterial Phagosome

The virulence of Legionella pneumophila is dependent on the Dot/Icm type IV protein secretion system, which translocates effectors into infected cells. A large number of such translocated proteins have been identified, but few of these proteins are necessary for intracellular replication of the pathogen, making it difficult to correlate these genes with specific cell-biological events associated with L. pneumophila infection. We report here the identification and characterization of a family of two substrates, SidJ and SdjA, with distinctive phenotypes. In contrast to many Dot/Icm substrates, whose expression levels are elevated when bacteria are grown to postexponential phase, SidJ is produced at a constant rate during the entire bacterial growth cycle. Mutation in sidJ causes a significant growth defect in both macrophage and amoeba hosts, but an sdjA mutant is detectably defective only in protozoan hosts. However, in the amoeba host a mutant lacking both sidJ and sdjA does not display a more severe growth defect than the sidJ mutant. Despite its significant intracellular growth defect, the sidJ mutant is still able to effectively evade fusion with lysosomes. Importantly, recruitment of endoplasmic reticulum (ER) proteins by vacuoles containing the sidJ mutant was considerably delayed in both mammalian and amoeba cells. Our results suggest that SidJ modulates host cellular pathways, contributing to the trafficking or retention of ER-derived vesicles to L. pneumophila vacuoles

Transforming Growth Factor beta 1 Gene Play a Novel Role in Innate Immune Response in Pelteobagrus fulvidraco

Transforming growth factor-beta 1 (TGF-beta 1) as a member of TGF-beta superfamily plays crucial roles in regulation of immune responses. Yellow catfish, Pelteobagrus fulvidraco, is one of the most important freshwater aquaculture species in China, but little is known about its genes related to immune response. The present study cloned cDNA encoding TGF-beta 1 from P. fulvidraco. The results showed the full-length cDNA of TGF-beta 1 is 2,816 bp and encodes 461 amino acids. The homology of P. fulvidraco TGF-beta 1 depicted 83% and 81% similarity to the TGF-beta 1 in Stegastes partitus and Pundamilia nyererei respectively. The phylogenetic tree construction revealed that P. fulvidraco is closely related to Astyanax mexicanus. Analysis of mRNA expression of TGF-beta 1 in different tissues (gonads, brain, liver, kidney, spleen, intestine, blood, gills, muscle and heart) revealed that TGF-beta 1 is predominantly expressed in liver and brain, followed by gill and spleen. TGF-beta 1 gene in gill and spleen up-regulated for 48h after Edwardsiella ictaluri and Flavobacterium columnare injection, then the expression showed a significant decrease (p<0.05). These results indicated that TGF-beta 1 contributes to the inherent immune reaction of P. fulvidraco

Ictal EEG in sunflower syndrome: Provoked or unprovoked seizures?

Sunflower syndrome (SS) is a rare, photosensitive epilepsy characterized by an attraction to light and highly stereotyped seizures with associated hand-waving (HW). It is controversial whether HW is part of the seizure or a provoking factor; therefore, we aimed to characterize the ictal electroencephalogram (EEG) in patients with SS. Video-EEG (vEEG) and charts of five patients with SS with HW during vEEG from Massachusetts General Hospital's Pediatric Epilepsy Program were reviewed and analyzed. In four out of five patients, the ictal EEG showed high amplitude (500-700 μV) 3-4 Hz generalized spike/polyspike-and-slow wave discharges, lasting 1.63-24.41 s. One hundred and twelve of 126 HW episodes, correlating to epileptiform activity (vEEG), had a lag time of less than 1.00 s (88.89%) between onset of HW and appearance of epileptiform activity. This suggests that HW does not induce seizure activity. Awareness of the ictal EEG features of this syndrome is important, as patients are frequently described as "self-inducing" their seizures.status: Published onlin

Spatiotemporal Characterization and Suppression Mechanism of Supersonic Inlet Buzz with Proper Orthogonal Decomposition Method

The buzz phenomenon of a typical supersonic inlet is analyzed using the unsteady Reynolds Average Navier-Stokes (RANS) simulation and proper orthogonal decomposition (POD) method. The dominant flow patterns and characteristics of the buzzed flow are obtained by decoupling the computed pressure field into spatial and temporal sub-parts based on the POD method. The supersonic inlet buzz phenomenon could be approximated as a product of decoupled temporal and spatial terms, and the one-dimensional (1D) mathematical model is therefore proposed. The standard deviations of the unsteady pressure fields from both the numerical simulation and the model prediction are compared. The limited discrepancy can be observed, and the good agreement validates the credibility of the proposed 1D model. The numerical simulation and the 1D model prediction are presented to explore the unsteady-jet control with a small perturbation. The results of the 1D model and the numerical simulation achieve good agreements with each other in terms of the overall trend. Finally, POD modal energy is employed to analyze the buzz suppression mechanism. When the jet frequency is identical to the dominant frequency of the buzz and the jet phase is opposite to the oscillation phase of the captured mass flow, the buzz suppression could be more efficient. The buzz suppression mechanism could be explained in two aspects. For one thing, the complex flow structure is suppressed and the first average modal energy in the inlet is increased. For another, the energy redistribution among each POD mode is achieved and the flow stability is gradually enhanced

Acoustic Modeling and Vibration Characteristics of Supersonic Inlet Buzz

The buzz phenomenon of a typical supersonic inlet is analyzed on the basis of numerical simulations and duct acoustic theory. Considering that the choked inlet could be treated as a duct with one end closed, a one-dimensional (1D) mathematical model based on the duct acoustic theory is proposed to describe the periodic pressure oscillation of the little buzz and the big buzz. The results of the acoustic model agree well with that of the numerical simulations and the experimental data. It could verify that the dominated oscillation patterns of the little buzz and the big buzz are closely related to the first and second resonant mode of the standing wave, respectively. The discrepancies between the numerical simulation and the ideal acoustic model might be attributed to the viscous damping in the fluid oscillation system. In order to explore the damping, a small perturbation jet is introduced to trigger the resonance of the buzz system and the nonlinear amplification effect of resonance might be helpful to estimate the damping. Through the comparison between the linear acoustic model and the nonlinear simulation, the calculated pressure oscillation damping of the little buzz and the big buzz are 0.33 and 0.16, which could be regarded as an estimation of real damping