136 research outputs found
Chip-based photonic radar for high-resolution imaging
Radar is the only sensor that can realize target imaging at all time and all
weather, which would be a key technical enabler for future intelligent society.
Poor resolution and large size are two critical issues for radars to gain
ground in civil applications. Conventional electronic radars are difficult to
address both issues especially in the relatively low-frequency band. In this
work, we propose and experimentally demonstrate, for the first time to the best
of our knowledge, a chip-based photonic radar based on silicon photonic
platform, which can implement high resolution imaging with very small
footprint. Both the wideband signal generator and the de-chirp receiver are
integrated on the chip. A broadband photonic imaging radar occupying the full
Ku band is experimentally established. A high precision range measurement with
a resolution of 2.7 cm and an error of less than 2.75 mm is obtained. Inverse
synthetic aperture (ISAR) imaging of multiple targets with complex profiles are
also implemented.Comment: 4 pages, 6figure
Synthesis and Antitumor Activity of N-Triazol-5-yl-oxazolidin-4-one Derivatives.
Fifteen novel N-triazol-5-yl-oxazolidin-4-ones were synthesized through a few of steps from the benzaldehydes. It was found that N-iodosuccinimide (NIS) can promote intramolecular amination reaction which is the key step of the syntheses, which will be used as new method for the intramolecular formation of nitrogen-containing heterocycles. Part of the compounds were evaluated for their anticancer activity. Among them, compounds 6a, 6b and 6c showed moderate antiprolifiration activity toward human breast cancer cells MDA-MB-231 cell lines, while the mild activity of 6a, 6b and 6d against human cervical cancer HeLa cell lines was confirmed in vitro assay
The Minority Matters: A Diversity-Promoting Collaborative Metric Learning Algorithm
Collaborative Metric Learning (CML) has recently emerged as a popular method
in recommendation systems (RS), closing the gap between metric learning and
Collaborative Filtering. Following the convention of RS, existing methods
exploit unique user representation in their model design. This paper focuses on
a challenging scenario where a user has multiple categories of interests. Under
this setting, we argue that the unique user representation might induce
preference bias, especially when the item category distribution is imbalanced.
To address this issue, we propose a novel method called
\textit{Diversity-Promoting Collaborative Metric Learning} (DPCML), with the
hope of considering the commonly ignored minority interest of the user. The key
idea behind DPCML is to include a multiple set of representations for each user
in the system. Based on this embedding paradigm, user preference toward an item
is aggregated from different embeddings by taking the minimum item-user
distance among the user embedding set. Furthermore, we observe that the
diversity of the embeddings for the same user also plays an essential role in
the model. To this end, we propose a \textit{diversity control regularization}
term to accommodate the multi-vector representation strategy better.
Theoretically, we show that DPCML could generalize well to unseen test data by
tackling the challenge of the annoying operation that comes from the minimum
value. Experiments over a range of benchmark datasets speak to the efficacy of
DPCML
Identification of bacteria and fungi responsible for litter decomposition in desert steppes via combined DNA stable isotope probing
IntroductionSoil microorganisms play crucial roles in determining the fate of litter in desert steppes because their activities constitute a major component of the global carbon (C) cycle. Human activities lead to increased ecosystem nitrogen (N) deposition, which has unpredictable impacts on soil microorganism diversity and functions. Nowadays, it is necessary to further study the succession of these microorganisms in the process of litter decomposition in desert steppe, and explore the effect of N deposition on this process. This issue is particularly important to resolve because it contributes to the broader understanding of nutrient cycling processes in desert steppes.MethodsIn this study, DNA stable isotope probing (DNA-SIP) was used to study changes in soil bacterial and fungal community composition and function during 8 weeks of culture of 13C-labeled litter in desert steppes.ResultsThe results were as follows: (1) Actinomycetota, Pseudomonadota, and Ascomycota are the main microorganisms involved in litter decomposition in desert steppes; (2) N deposition (50 kg ha−1 year−1) significantly increased the relative abundance of some microorganisms involved in the decomposition process; and (3) N deposition likely promotes litter decomposition in desert steppes by increasing the abundances of N cycles bacteria (usually carrying GH family functional genes).DiscussionThese findings contribute to a deeper understanding of the C assimilation mechanisms associated with litter residue production, emphasizing the importance of extensive C utilization
Neural Speaker Diarization Using Memory-Aware Multi-Speaker Embedding with Sequence-to-Sequence Architecture
We propose a novel neural speaker diarization system using memory-aware
multi-speaker embedding with sequence-to-sequence architecture (NSD-MS2S),
which integrates the strengths of memory-aware multi-speaker embedding (MA-MSE)
and sequence-to-sequence (Seq2Seq) architecture, leading to improvement in both
efficiency and performance. Next, we further decrease the memory occupation of
decoding by incorporating input features fusion and then employ a multi-head
attention mechanism to capture features at different levels. NSD-MS2S achieved
a macro diarization error rate (DER) of 15.9% on the CHiME-7 EVAL set, which
signifies a relative improvement of 49% over the official baseline system, and
is the key technique for us to achieve the best performance for the main track
of CHiME-7 DASR Challenge. Additionally, we introduce a deep interactive module
(DIM) in MA-MSE module to better retrieve a cleaner and more discriminative
multi-speaker embedding, enabling the current model to outperform the system we
used in the CHiME-7 DASR Challenge. Our code will be available at
https://github.com/liyunlongaaa/NSD-MS2S.Comment: Submitted to ICASSP 202
Pharmacokinetic and Pharmacogenetic Factors Contributing to Platelet Function Recovery After Single Dose of Ticagrelor in Healthy Subjects
Objectives: This study aimed to elucidate the contribution of candidate single nucleotide polymorphisms (SNPs) related to pharmacokinetics on the recovery of platelet function after single dose of ticagrelor was orally administered to healthy Chinese subjects.Methods: The pharmacokinetic profiles of ticagrelor and its metabolite AR-C124910XX (M8), and the platelet aggregation (PA), were assessed after 180 mg of single-dose ticagrelor was orally administered to 51 healthy Chinese subjects. Effects of CYP2C19*2, CYP2C19*3, CYP3A5*3, UGT1A1*6, UGT1A1*28, UGT2B7*2, UGT2B7*3, SLCO1B1 388A>G, and SLCO1B1 521T>C, on the pharmacokinetics of ticagrelor and M8, and platelet function recovery were investigated.Results: The time to recover 50% of the maximum drug effect (RT50) ranging from 36 to 126 h with 46.9% CV had a remarkable individual difference and was positively associated with the half-life (t1/2) of M8 (r = 0.3901, P = 0.0067). The time of peak concentration (Tmax) of ticagrelor for CYP2C19*3 GG homozygotes was significantly higher than that of GA heterozygotes (P = 0.0027, FDR = 0.0243). Decreased peak concentration (Cmax) of M8 was significantly associated with SLCO1B1 388A>G A allele (P = 0.0152, FDR = 0.1368). CYP2C19*2 A was significantly related to decreased Cmax of M8 (P = 0.0455, FDR = 0.2048). While, the influence of these nine SNPs on the recovery of platelet function was not significant.Conclusion: Our study suggests that the elimination of M8 is an important factor in determining the recovery of platelet function. Although CYP2C19 and SLCO1B1 genetic variants were related to the pharmacokinetics of ticagrelor or M8, they did not show a significant effect on the platelet function recovery in this study.Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03092076, identifier: NCT0309207
Three-dimensional pseudocontinuous arterial spin labeling perfusion imaging shows cerebral blood flow perfusion decline in attention-deficit/hyperactivity disorder children
PurposeTo investigate the feasibility of three-dimensional pseudocontinuous arterial spin labeling (3D-pcASL) perfusion imaging in the brain of children with Attention-deficit/hyperactivity disorder (ADHD).MethodsA total of 78 ADHD children aged 5–13 years were prospectively selected as the study group, and 89 healthy children matched in age and sex were selected as the control group. All children underwent MRI conventional sequence, 3D-pcASL, and 3D-T1 sequence scans. The brain gray and white matter volume and cerebral blood flow (CBF) perfusion values were obtained by software post-processing, and were compared and analyzed in the two groups to find out their characteristics in the brain of ADHD children.ResultsThe total brain volume and total CBF values were lower in ADHD children than in healthy children (P < 0.05); the gray and white matter volumes in the frontal lobe, temporal lobe, hippocampus, caudate nucleus, putamen, globus pallidus and other brain regions were lower in ADHD children than in healthy children (P < 0.05); the gray matter CBF values in the frontal lobe, temporal lobe, hippocampus, caudate nucleus, putamen, globus pallidus and other brain regions were lower in ADHD children than in healthy children (P < 0.05); the differences between the white matter CBF values of white matter in the said brain regions of ADHD children and healthy children were not statistically significant (P > 0.05); and the CBF values in frontal lobe and caudate nuclei could distinguish ADHD children (AUC > 0.05, P < 0.05).ConclusionThe 3D-pcASL technique showed reduced cerebral perfusion in some brain regions of ADHD children
Copper Salt-Catalyzed Formation of a Novel Series of Triazole-Spirodienone Conjugates with Potent Anticancer Activity.
Copper salt-catalyzed oxidative amination resulted in the formation of a novel series of triazole-spirodienone conjugates, 4-triazolyl-1-oxa-4-azaspiro[4,5]deca-6,9-dien-3,8-diones and 4-triazolyl-1-oxa-4-azaspiro[4,5]deca-6,9-dien-8-ones. A single crystal of compound 1p among them was grown and analyzed by X-ray crystallography. These compounds were evaluated for their antiproliferative activities against MDA-MB-231, HeLa, A549 and MCF-7 cell lines. Most of them showed moderate to high anticancer potency in the four cancer cell lines. The discovery of the triazole-spirodienone conjugates as cytotoxic agents against cancer cells may open up a new field in which these novel small molecules could be further explored as promising anticancer agents
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