127 research outputs found
Reactivity of Acyclic (Pentadienyl) iron (1+) Cations with Phosphorous-stabilized Carbon Nucleophiles and with Nitrogen Nucleophiles
A lot of studies regard organoiron compounds have been made in recent years.Nucleophilic addition with soft nucleophiles such as malonate anions or phosphonatestabilized carbon nucleophiles, or harder nucleophiles such as organolithium or Grignardreagents to an acyclic (pentadienyl)iron cation results in the (pentenediyl)iron complexes.
Reaction of (pentadienyl)iron complexes with paraformaldehyde via Horner-Emmonsolefination will give enolate complex. Oxidation of the enolate leads to the formation ofcyclopropane carboxylates. Further oxidation of divinylcyclopropane carboxylates canform cycloheptadiene.
The reacivity of acyclic (pentadienyl)iron cations with nitrogen nucleophiles such aspotassium phthalimide were examined, which could be used as potential routes tosynthesis natural product. Click chemistry was also introduced to see the reactivity oforganoiron azide with terminal alkynes.
We have also proposed to synthesize a model of bicycle [4,1,0] heptanes via the ringclosing metathesis of vinylcyclopropanes
Reactivity of Acyclic (pentadienyl)iron(1+) Cations with Phosphonate Stabilized Nucleophiles: Application to the Synthesis of Oxygenated Metabolites of Carvone
The addition of phosphonate stabilized carbon nucleophiles to acyclic (pentadienyl)iron(1+) cations proceeds predominantly at an internal carbon to afford (pentenediyl)iron complexes. Those complexes bearing an electron withdrawing group at the σ-bound carbon (i.e., 13/14) are stable and isolable, while complexes which do not contain an electron withdrawing group at the σ-bound carbon undergo CO insertion, reductive elimination and conjugation of the double bond to afford cyclohexenone products (21/22). Deprotonation of the phosphonate 13/14 or 21 and reaction with paraformaldehyde affords the olefinated products. This methodology was utilized to prepare oxygenated carvone metabolites (±)-25 and (±)-26
Fractional strong matching preclusion for two variants of hypercubes
Let F be a subset of edges and vertices of a graph G. If G-F has no fractional perfect matching, then F is a fractional strong matching preclusion set of G. The fractional strong matching preclusion number is the cardinality of a minimum fractional strong matching preclusion set. In this paper, we mainly study the fractional strong matching preclusion problem for two variants of hypercubes, the multiply twisted cube and the locally twisted cube, which are two of the most popular interconnection networks. In addition, we classify all the optimal fractional strong matching preclusion set of each
Segment Any Cell: A SAM-based Auto-prompting Fine-tuning Framework for Nuclei Segmentation
In the rapidly evolving field of AI research, foundational models like BERT
and GPT have significantly advanced language and vision tasks. The advent of
pretrain-prompting models such as ChatGPT and Segmentation Anything Model (SAM)
has further revolutionized image segmentation. However, their applications in
specialized areas, particularly in nuclei segmentation within medical imaging,
reveal a key challenge: the generation of high-quality, informative prompts is
as crucial as applying state-of-the-art (SOTA) fine-tuning techniques on
foundation models. To address this, we introduce Segment Any Cell (SAC), an
innovative framework that enhances SAM specifically for nuclei segmentation.
SAC integrates a Low-Rank Adaptation (LoRA) within the attention layer of the
Transformer to improve the fine-tuning process, outperforming existing SOTA
methods. It also introduces an innovative auto-prompt generator that produces
effective prompts to guide segmentation, a critical factor in handling the
complexities of nuclei segmentation in biomedical imaging. Our extensive
experiments demonstrate the superiority of SAC in nuclei segmentation tasks,
proving its effectiveness as a tool for pathologists and researchers. Our
contributions include a novel prompt generation strategy, automated
adaptability for diverse segmentation tasks, the innovative application of
Low-Rank Attention Adaptation in SAM, and a versatile framework for semantic
segmentation challenges
Fractional matching preclusion for butterfly derived networks
The matching preclusion number of a graph is the minimum number of edges whose deletion results in a graph that has neither perfect matchings nor almost perfect matchings. As a generalization, Liu and Liu [18] recently introduced the concept of fractional matching preclusion number. The fractional matching preclusion number (FMP number) of G, denoted by fmp(G), is the minimum number of edges whose deletion leaves the resulting graph without a fractional perfect matching. The fractional strong matching preclusion number (FSMP number) of G, denoted by fsmp(G), is the minimum number of vertices and edges whose deletion leaves the resulting graph without a fractional perfect matching. In this paper, we study the fractional matching preclusion number and the fractional strong matching preclusion number for butterfly network, augmented butterfly network and enhanced butterfly network
Large Distance Modification of Newtonian Potential and Structure Formation in Universe
In this paper, we study the effects of super-light brane world perturbative
modes on structure formation in our universe. As these modes modify the large
distance behavior of Newtonian potential, they effect the clustering of a
system of galaxies. So, we explicitly calculate the clustering of galaxies
interacting through such a modified Newtonian potential. We use a suitable
approximation for analyzing this system of galaxies, and discuss the validity
of such approximations. We observe that such corrections also modify the virial
theorem for such a system of galaxies.Comment: 13 pages, 3 captioned figure
Towards Robust SDRTV-to-HDRTV via Dual Inverse Degradation Network
Recently, the transformation of standard dynamic range TV (SDRTV) to high
dynamic range TV (HDRTV) is in high demand due to the scarcity of HDRTV
content. However, the conversion of SDRTV to HDRTV often amplifies the existing
coding artifacts in SDRTV which deteriorate the visual quality of the output.
In this study, we propose a dual inverse degradation SDRTV-to-HDRTV network
DIDNet to address the issue of coding artifact restoration in converted HDRTV,
which has not been previously studied. Specifically, we propose a
temporal-spatial feature alignment module and dual modulation convolution to
remove coding artifacts and enhance color restoration ability. Furthermore, a
wavelet attention module is proposed to improve SDRTV features in the frequency
domain. An auxiliary loss is introduced to decouple the learning process for
effectively restoring from dual degradation. The proposed method outperforms
the current state-of-the-art method in terms of quantitative results, visual
quality, and inference times, thus enhancing the performance of the
SDRTV-to-HDRTV method in real-world scenarios.Comment: 10 page
Robust Multimodal Failure Detection for Microservice Systems
Proactive failure detection of instances is vitally essential to microservice
systems because an instance failure can propagate to the whole system and
degrade the system's performance. Over the years, many single-modal (i.e.,
metrics, logs, or traces) data-based nomaly detection methods have been
proposed. However, they tend to miss a large number of failures and generate
numerous false alarms because they ignore the correlation of multimodal data.
In this work, we propose AnoFusion, an unsupervised failure detection approach,
to proactively detect instance failures through multimodal data for
microservice systems. It applies a Graph Transformer Network (GTN) to learn the
correlation of the heterogeneous multimodal data and integrates a Graph
Attention Network (GAT) with Gated Recurrent Unit (GRU) to address the
challenges introduced by dynamically changing multimodal data. We evaluate the
performance of AnoFusion through two datasets, demonstrating that it achieves
the F1-score of 0.857 and 0.922, respectively, outperforming the
state-of-the-art failure detection approaches
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