A readily accessible multifunctional probe: simultaneous recognition of the cation ZN²⁺ and the anion F⁻ via distinguishable wavelengths

The probe 1 was readily prepared via condensation of 8-formyl-7-hydroxy-coumarin and carbonic dihydrazide in a one-step procedure. Probe 1 exhibited high sensitivity and selectivity towards Zn²⁺ and F⁻ through a “turn-on” fluorescence response and/or ratiometric colorimetric response with low detection limits of the order of 10-8 M. The complex behaviour was fully investigated by spectral titration, isothermal titration calorimetry, 1H NMR spectroscopic titration and mass spectrometry. Interestingly, probe 1 not only recognizes the cation Zn²⁺ and the anion F⁻, but can also distinguish between these two ions via the max wavelength in their UV-vis spectra (360 nm for 1-Zn²⁺ versus 400 nm for 1-F⁻ complex) or their fluorescent spectra (λₑₓ / λₑm = 360 nm/ 454 nm for 1-Zn²⁺ versus λₑₓ / λₑm = 400 nm/ 475 nm for 1-F⁻ complex) due to their differing red-shifts. Additionally, probe 1 has been further explored in the detection of Zn²⁺ in living cells

A 2-Styryl-1,8-naphthyridine derivative as a versatile fluorescent probe for the selective recognition of Hg²⁺, Ag⁺ and F⁻ ions by tuning the solvent

A novel fluorescent probe 1 has been synthesized by a microwave reaction, and its ion-binding and fluorescence-sensing properties have been investigated under different solvent conditions. The analysis results indicated that probe 1 can act as a multiple analysis probe by simply tuning the solvent. Probe 1 exhibited high selectively toward Hg²⁺ through fluorescence quenching in H₂O/DMF. In H₂O/1,4-dioxane solution, probe 1 selectively recognized and discriminated between Ag⁺ and Hg²⁺ displaying ratiometric behaviour. Moreover, probe 1 readily recognized the anion F⁻ via the ratiometric fluorescent mode in CH3CN. Furthermore, distinct colour changes were observed under UV light, which can be seen by the naked eye and thus used for distinguishing Hg²⁺, Ag+ and F⁻ from the other ions screened herein using probe 1. Interestingly, almost pure white light emission was evident by simply tuning the F⁻ anion-concentration, which makes this system a potential candidate for smart and tunable luminescent materials

Tubular and cellular localization of the cardiac L-type calcium channel in rat kidney

Tubular and cellular localization of the cardiac L-type calcium channel in rat kidney.BackgroundThe mRNAs of several types of calcium channels have been identified in intact rat kidney, and L-type calcium channels cause changes in intracellular calcium in primary cultures of distal tubule cells. The aim of this study was to evaluate the tubular and cellular distribution of the α1C subunit of the L-type calcium channel in intact kidney.MethodsRT-PCR and Northern blot analysis were used to assess the regional abundance of the mRNA of this channel. Immunocytochemistry combined with confocal microscopy and surface biotinylation were applied to determine the tubular and cellular localization of the protein.ResultsNorthern blot and RT-PCR analysis indicated that the mRNA of the α1C subunit of the cardiac L-type calcium channel was present in whole rat kidney, kidney tubules and kidney cell lines. Western blot of lysates from whole kidney, kidney tubules or cell lines revealed bands of ∼190 kD for the α1C subunit and ∼60 kD for the β3 subunit. Confocal immunohistochemistry indicated that the α1C subunit of this channel was co-expressed in cells of the distal tubule that express calbindin-D28K, but not in intercalated cells. The α1C subunit was also highly expressed in both outer and inner medullary collecting ducts. Serial confocal microscopic images or surface biotinylation experiments determined that the channel was predominantly on the basolateral membrane but had some distribution on the apical membrane.ConclusionsThe distribution and cellular localization of the α1C subunit of cardiac L-type calcium channel suggest it is probably involved in intracellular and membrane calcium signaling

A three-dimensional (time, wavelength and intensity) functioning fluorescent probe for the selective recognition/discrimination of Cu2+, Hg2+, Fe3+ and F- ions

We have strategically incorporated three different fluorophores at tren to construct a multi-energy donor/acceptor “smart” probe L. This probe operates by using three-dimensional scales (response time, wavelength and fluorescence intensity) which allows for the selective recognition and discrimination of the Cu2+, Hg2+, Fe3+ and F− ions

Highly selective recognition of Al3+ and I- ions using a bifunctional fluorescent probe

A tripodal fluorescent probe L1 armed with rhodamine B and 1-naphthaleneisothiocyanates was prepared in high yield. A study of the recognition properties revealed that probe L1 exhibited high sensitivity and selectivity towards Al3⁺ through a “FRET” fluorescence response and colorimetric response with low detection limits of the order of 10-8 M. Meanwhile, probe L1 also possessed high recognition capability for I⁻ through fluorescent decay, which given there are comparatively few selective fluorescent probes for I⁻, is significant. Furthermore, the complexation mechanisms were fully investigated by spectral titrations, 1H NMR spectroscopic titrations and mass spectrometry. The utility of probe L1 as a biosensor in living cells (PC3 cells) towards Al3⁺ ions has also been demonstrated

Towards Better Query Classification with Multi-Expert Knowledge Condensation in JD Ads Search

Search query classification, as an effective way to understand user intents, is of great importance in real-world online ads systems. To ensure a lower latency, a shallow model (e.g. FastText) is widely used for efficient online inference. However, the representation ability of the FastText model is insufficient, resulting in poor classification performance, especially on some low-frequency queries and tailed categories. Using a deeper and more complex model (e.g. BERT) is an effective solution, but it will cause a higher online inference latency and more expensive computing costs. Thus, how to juggle both inference efficiency and classification performance is obviously of great practical importance. To overcome this challenge, in this paper, we propose knowledge condensation (KC), a simple yet effective knowledge distillation framework to boost the classification performance of the online FastText model under strict low latency constraints. Specifically, we propose to train an offline BERT model to retrieve more potentially relevant data. Benefiting from its powerful semantic representation, more relevant labels not exposed in the historical data will be added into the training set for better FastText model training. Moreover, a novel distribution-diverse multi-expert learning strategy is proposed to further improve the mining ability of relevant data. By training multiple BERT models from different data distributions, it can respectively perform better at high, middle, and low-frequency search queries. The model ensemble from multi-distribution makes its retrieval ability more powerful. We have deployed two versions of this framework in JD search, and both offline experiments and online A/B testing from multiple datasets have validated the effectiveness of the proposed approach

Genetic polymorphisms of CYP2A13 and its relationship to nasopharyngeal carcinoma in the Cantonese population

Nasopharyngeal carcinoma (NPC) is characterized by a high prevalence in Southern China, especially among Cantonese individuals of the Guangdong Province. Epidemiological studies have suggested that frequent exposure to high levels of nitrosamine from preserved foods such as salted fish could be a risk factor for NPC. Cytochrome P450 encompasses a family of enzymes that metabolize carcinogens and CYP2A13, a member of this family, is expressed predominantly in the respiratory tract with the highest levels in the nasal mucosa. In an effort to test whether a correlation exists between CYP2A13 genetic polymorphism and the risk of developing NPC, we sequenced all nine exons and the exon-intron junctions of the CYP2A13 gene in 45 NPC patients. We identified a total of 21 single nucleotide polymorphism (SNPs), including 7 novel SNPs. The most frequent functional variant allele was 74A-1757G-3375T-7233G with a haplotype frequency of 7.8% in the 45 NPC cases. In addition, a stop codon mutation was detected in one case. We then selected the 3 most frequent SNPs and one stop codon mutation to expand our study to a case-control analysis within the Cantonese population. A novel haplotype consisting 8 SNPs in introns, and four additional novel SNPs were identified; but no correlation between CYP2A13 genetic polymorphism and individual susceptibility to NPC was observed