Phosphomolybdates for Dual-Mode Photoelectrochemical Sensing toward Trace Chromium(VI) and Tetracycline.

Highly sensitive photoelectrochemical (PEC) sensors for trace carcinogens, such as heavy metal chromium(VI) [Cr(VI)] and antibiotic tetracycline (TC) are crucial. Herein, by integration of photoactive and redox phosphomolybdates with conjugated organic components, types of dual-mode PEC sensors were synthesized for sensing trace Cr(VI) and TC pollutants, with formulas of (H2bimb)2[Co2(bimb)1.5][Co(H2O)4][Co(P4Mo6O31H6)2]·6H2O (1), (H2bib)2[Co(H2O)3][Co2(H2O)5][Co(P4Mo6O31H6)2]·9H2O (2), and (H2bib)6[Co(Hbib)2(H2O)5][Co(P4Mo6O31H7)2]2·15H2O (3), where bimb represents 1,4-bis(1-imidazolyl)benzene and bib is 4,4'-bis(imidazolyl)bibphenyl. Hybrid 1 consisted of a three-dimensional framework structure constructed by Co{P4Mo6}2 clusters and one-dimensional (1D) {Co-bimb} chains, hybrid 2 exhibited 1D Co ion-bridged Co{P4Mo6}2 chains hydrogen-bonding with [H2bib]2+ cations, and hybrid 3 showed a discrete hybrid structure built upon a Co{P4Mo6}2 cluster modified by the {Co-bib} unit. Hybrids 1-3 displayed wide spectral absorption and excellent electrochemical redox properties, enabling dual-mode PEC responses to Cr(VI) reduction and TC oxidation. For Cr(VI) detection, hybrids 1-3 exhibited high sensitivities of 364.40, 225.72, and 124.29 µA·µM-1 as well as "nM" level detection limits (LODs) of 4.9, 10.0, and 11.0 nM, respectively. For TC detection, the sensitivities of hybrids 1-3 were 494.72, 308.78, and 174.03 µA·µM-1 and the LODs were 5.2, 6.1, and 12.9 nM, respectively. This research offers significant insights into designing efficient PEC sensors for the detection of environmental pollutants.

Bridging Component Strategy in Phosphomolybdate-Based Sensors for Electrochemical Determination of Trace Cr(VI).

Rapid and sensitive electrochemical determination of trace carcinogenic Cr(VI) pollutants remains an urgent and important task, which requires the development of active sensing materials. Herein, four cases of reduced phosphomolybdates with formulas of the (H2bib)3[Zn(H2PO4)]2{Mn[P4Mo6O31H7]2}·6H2O (1), (H2bib)2[Na(H2O)]2[Mn(H2O)]2{Mn[P4Mo6O31H6]2}·5H2O (2), (H2bib)3[Mo2(µ2-O)2(H2O)4]2{Ni[P4Mo6O31H2]2}·4H2O (3), and (H2bib)2{Ni[P4Mo6O31H9]2}·9H2O (4) (bib = 4,4'-bis(1-imidazolyl)-biphenyl) were hydrothermally synthesized under the guidance of a bridging component strategy, which function as effective electrochemical sensors to detect trace Cr(VI). The difference of hybrids 1-4 is in the inorganic moiety, in which the reduced phosphomolybdates {M[P4MoV6O31]2} (M{P4Mo6}2) exhibited different arrangements bridged by different cationic components ({Zn(H2PO4)} subunit for 1, [Mn2(H2O)2]4+ dimer for 2, and [MoV2(µ2-O)2(H2O)4]6+ for 3). As a result, hybrids 1 and 3 display noticeable Cr(VI) detection activity with low detection limits of 14.3 nM (1.48 ppb) for 1 and 6.61 nM (0.69 ppb) for 3 and high sensitivities of 97.3 and 95.3 µA·mM-1, respectively, which are much beyond the World Health Organization's detection threshold (0.05 ppm) and superior to those of the contrast samples (inorganic Mn{P4Mo6}2 salt and hybrid 4), even the most reported noble-metal catalysts. This work supplies a prospective pathway to build effective electrochemical sensors based on phosphomolybdates for environmental pollutant treatment.

Bifunctional Sensors Based on Phosphomolybdates for Detection of Inorganic Hexavalent Chromium and Organic Tetracycline.

Exploring effective sensors for detecting possible hazards in a water system are greatly significant. This work proposed a strategy for stable and effective bifunctional sensors via incorporating hourglass-type phosphomolybdates into metal-organic fragments to construct a high-dimensional framework. Two hourglass-type phosphomolybdate-based electrochemical sensors toward heavy metal ion Cr(VI) and tetracycline (TC) detection were designed with the formula [CoII2(H2O)4NaI2][CoII(Hbpe)][NaI(bpe)1.5]{CoII[PV4MoV6O31H6]2}·9H2O (1) and [CoII(H2O)4NaI3][CoII(Hbpe)][CoII(bpe)]{CoII[PV4MoV6O31H6]2}·9H2O (2) [bpe = 1,2-di(4-pyridyl)ethylene]. Structural analysis showed that hybrids 1 and 2 possess three-dimensional POM-supported network features with favorable stability and exhibit reversible redox properties. Experiments found that this kind of hybrids as efficient sensors have excellent electrochemical performance toward Cr(VI) detection with high sensitivities of 0.111 µA·µM-1 for 1 and 0.141 µA·µM-1 for 2, fast response time of 1 s, and low detection limits of 30 nM for 1 and 27 nM for 2, which far meet the standard of WHO for drinking water. Moreover, hybrids 1-2 also exhibit fast responses to TC detection with sensitivities of 0.0073 and 0.022 µA·mM-1 and detection limits of 0.426 and 0.084 mM. This work offers a novel strategy for the purposeful design of efficient POM-based electrochemical sensors for accurate determination of contaminants in a practical water system.

Interactive Field Effect of Atomic Bonding Forces on the Equivalent Elastic Modulus Estimation of Micro-Level Single-Crystal Copper by Utilizing Atomistic-Continuum Finite Element Simulation.

This study uses the finite element analysis (FEA)-based atomistic-continuum method (ACM) combined with the Morse potential of metals to determine the effects of the elastic modulus (E) of a given example on atomic-level single-crystal copper (Cu). This work aims to overcome the estimated drawback of a molecular dynamic calculation applied to the mechanical response of macro in-plane-sized and atomic-level-thick metal-based surface coatings. The interactive energy of two Cu atoms within a face-centered metal lattice was described by a mechanical response of spring stiffness. Compared with the theoretical value, the parameters of the Morse potential dominated the predicted accuracy through the FEA-based ACM. Moreover, the analytic results indicated that the effective E of a single-crystal Cu was significantly sensitive to the given range of the interactive force field among atoms. The reliable elastic moduli of 86.8, 152.6, and 205.2 GPa along the Cu(100), Cu(110), and Cu(111) orientations of the Cu metal were separately acquired using the presented FEA-based ACM methodology.

Whether Fire-needle Therapy Benefits Plaque Psoriasis: A Multicenter, Randomized, and Controlled Trial.

OBJECTIVE: To observe the clinical effectiveness and safety of fire-needle therapy, an external approach of Chinese medicine in treating plaque psoriasis. METHODS: This study was a two-parallel-arm randomized controlled trial. A total of 151 participants with plaque psoriasis were randomly assigned to the fire-needle therapy group (treatment group, 76 cases) or the control group (75 cases) at a 1:1 allocation ratio using SAS software. All participants received Oral Huoxue Jiedu Decoction (, HXJDD) and applied externally vaseline cream twice a day. Participants in the treatment group received fire-needle therapy once weekly for 4 weeks plus HXJDD and vaseline cream applied the same as the control group. The primary outcome measure was Psoriasis Area and Severity Index (PASI) score, and the secondary outcomes were Dermatology Life Quality Index (DLQL), and Hamilton Anxiety Rating Scale (HAMA), as well as Chinese medicine (CM) syndrome score and photos of target lesions. The indices were evaluated before and after treatment. RESULTS: Sixty-eight patients in each group completed the study. The treatment group has not yet achieved significant improvement in PASI score (P>0.05) compared to the control group. However, significant differences were found between the two groups in relieving CM syndrome (P<0.05) and improving quality of life (P<0.05). CONCLUSION: Fire-needle appears to be safe and may have benefit for psoriasis, the short-term treatment and small sample size limit the conclusions of this study. Further rigorous randomized controlled trials with longer treatment are recommended.