Search

Relation extraction is one of the most important intelligent information extraction technologies, which can be used to construct and optimize services in intelligent communication systems (ICS). One issue with the existing relation extraction approaches is that they use one-sided sentence embedding as their final prediction vector, which degrades relation extraction performance. The innovative relation extraction model REEGAT (RoBERTa Entity Embedding and Graph Attention networks enhanced sentence representation) that we present in this paper, incorporates the concept of enhanced word embedding from graph neural networks. The model first uses RoBERTa to obtain word embedding and PyTorch embedding to obtain relation embedding. Then, the multi-headed attention mechanism in GAT (graph attention network) is introduced to weight the word embedding and relation embedding to enrich further the meaning conveyed by the word embedding. Finally, the entity embedding component is used to obtain sentence representation by pooling the word embedding from GAT and the entity embedding from named entity recognition. The weighted and pooled word embedding contains more relational information to alleviate the one-sided problem of sentence representation. The experimental findings demonstrate that our model outperforms other standard methods.

In this paper, we developed a red-emitting fluorescent probe TPSN based on triphenylamine-functionalized benzothiazole salts. TPSN exhibits a strong luminescence emission at about 637 nm in viscous media. Moreover, the fluorescence intensity of TPSN enhances approximately 94-fold from water to 99% glycerol. Cell imaging experiments reveals that TPSN presents high specificity for mitochondrial localization. The related mechanism study indicates that the localization property of TPSN is independent of the mitochondrial membrane potential. As a result, TPSN offers a promising tool to monitor the mitochondria viscosity in living cells.

Metal complexes are expected to serve as efficient imaging probes to understand the biological process. In this work, a series of new ZnX2 (X = Cl, Br, I) complexes (DMT-ZnCl2, DMT-ZnBr2 and DMT-ZnI2) based on terpyridine were synthesized and fully characterized. X-ray crystal structure analysis demonstrate that the coplanarity within the molecules presents a certain regularity (DMT-ZnCl2 > DMT-ZnBr2 > DMT-ZnI2). The photophysical studies demonstrate the absorption bands showed a regular bathochromic-shift from DMT-ZnCl2 to DMT-ZnI2 along with the fluorescence intensity and the quantum yields decreasing. Biological tests reveal that all the Zn(II) complexes possess low cytotoxicity, good membrane permeability and good photostability, and exhibit a strong fluorescence in the cytosolic space in living Hela cells. Given mentioned above, the Zn(II) complexes can act as a promising candidate for biological imaging agent.

A series of novel quinoline derivatives L1–L3 with a D π A type were developed as a fluorescent viscosity probe in vitro. L1–L3 displayed very weak emission in nonviscous media and remarkable fluorescence enhancement with the viscosity augment in the water/glycerol system, especially for L2. Different substituent units exhibit a considerable influence on the photophysical properties and response sensitivity of the probes to viscosity. Probes L1–L3 exhibited a direct linear relationship well between log (I/I0) and the log η, which allowed us to quantitatively measure the environmental viscosity. Moreover, L2 modified with 1-butoxy-2-methoxybenzene has been certified to be more sensitive to viscosity because of moderate electron-donating ability. Cell imaging experiments illustrated that L1–L3 is suitable for visualizing the viscosity changes in living cells. As a result, the present work offers a strategy for rationally designing fluorescence probe for viscosity detection in living cells.

In this paper, two novel benzothiazole derivatives EtSN and OAcSN with a D–π–A configuration were developed as fluorescent probes for the detection of HSO3−. Compared with OAcSN, probe EtSN, bearing ester group, displayed a lower detection limit and faster response time. Upon treatment with HSO3−, EtSN and OAcSN displayed noticeable color change from yellow (EtSN)/red (OAcSN) to coreless, respectively. Competitive experiments indicated that EtSN and OAcSN had higher fluorescence selectivity towards HSO3− than other analytes. The sensing mechanism was further illustrated by 1H NMR and TD-DFT.

A novel water-soluble fluorescent probe L based on indole salts has been designed, synthesized and fully characterized. The systematic investigations demonstrated that probe L shows red emission and the fluorescence intensity is linear with the viscosity of the medium. Probe L is able to selectively accumulate in mitochondria within 1 min without any additional reagents for membrane permeabilization. It has been used to distinguish the viscosity differences between mitochondria in normal and nystatin-treated HeLa cells. In addition, due to the good photostability, probe L can be used to monitor the dynamics of mitochondria. These results support that probe L might provide a promising approach for the fluorescence detection of mitochondrial viscosity in living biological systems.

To develop novel fluorescent probes for detecting endogenous histidine (His) plays significant roles in physiological and pathological fields. Herein, a non-emissive Ir(III) complex [Ir(C–N)2(CH3CN)2]+NO3− (IrCN, C–N represents 2-phenylpyridine derivative) has been demonstrated to be a reaction-based fluorescent probe for the recognition of His in HEPES buffer. It is found that IrCN can selectively detect His with a distinct “turn-on” luminescence and low limit of detection (LOD = 0.62 μM), relying on which, IrCN can light-up the cytoplasm and nuclear region of the fixed cells, exhibiting negligible cytotoxicity and suitable solubility under test concentration.

Developing new probes for visualizing H2S in the endoplasmic reticulum (ER) is of great significance in physiological and pathological fields in that the probe can antagonise ER stress. Herein, we try to explore efficient reporting fluorophores based on three pyrimidine derivatives (L1, L2 and L3), and eventually, a novel probe WH2S was fabricated by using emissive pyrimidine derivative (L1) as the reporting fluorophore. Upon the addition of H2S, the probe processed a thiolytic cleavage to regenerate L1, delivering a remarkable fluorescence enhancement. Probe WH2S presents a perfect selectivity, high sensitivity and low detection limit (3.81 μM) towards H2S in the buffer media. Most importantly, fluorescence microscopy experiments demonstrate that WH2S can precisely accumulate in ER and detect exogenous/endogenous H2S at cellular level. These results imply that probe WH2S possesses great potentiality in tracking target H2S in complicated and changeable living systems.

Small-molecule fluorescent dyes with excellent biocompatibility and deep tissue permeability are playing an important part in biological development. Herein, a series of D-A typesmall-molecules L1, L2 and L3 containing different terminal groups have been designed and synthesized, of which the structures were confirmed by single crystal X-ray diffraction analysis. Interestingly, it was found that different end groups within the molecules gave an obvious effect on the fluorescent emission properties while unconspicuous influence on the absorption properties. Moreover, these compounds were successfully applied to fluorescent imaging for staining cellular endoplasmic reticulum (ER) and tissue slice from mouse exhibiting negligible cytotoxicity as well as favourable permeability. These compounds may act as probes for ER targeting and alternative bio-imaging reagents.