Stability, spectroscopic, electrochemistry and QTAIM analysis of Cu-Znn-1On clusters for glucose sensing application: A study on theoretical and experimental insights

Clusters of (ZnO)_n (n = 2-4) have been shown to play a central role in the detection of glucose entity based on the existence of photo-induced electrons (PE), which facilitates the interaction between (ZnO)_n clusters and glucose entity guests. The electrochemistry experiment has confirmed the detection of glucose by the title clusters. The optimization, energetic parameters, and vibrational frequency calculations have indicated that the Cu-Zn_n-1O_n-glucose are more stable than the (ZnO)_n-glucose complexes. It has been demonstrated that the Cu doping enhanced the chemical behavior of the clusters and formed a high intramolecular charge transfer (ICT) in the system. The glucose sensing by all the forms of Cu-Zn_n-1O_n clusters showed that the Cu-Zn₃O₄, Cu-Wurtzite, and Cu-Rocksalt clusters are the most suitable for adsorbing the glucose guest. The HOMO/LUMO iso-surfaces of the complexes showed that the electron concentrations are localized in the d orbitals and mainly in the form of the d¹⁰ orbitals around Zn atoms. The molecular electrostatic potential (MEP) has clearly indicated that a high charge transfer occurs between the copper and the oxygen atoms, which facilitate the adsorption of glucose. The reactivity parameters also indicated that the Wurtzite-glucose complex has a high electrophilicity index (ω), which means a good acceptor behavior to interact with glucose. Additionally, the bond between the (ZnO)_n clusters and the glucose polar element has been studied in detail by using QTAIM theory. Finally, the theoretical and experimental studies prove that the Cu-Zn_n-1O_n clusters are very suitable and competent compounds for detecting glucose.

Azo-methoxy-calix[4]arene complexes with metal cations for chemical sensor applications: Characterization, QTAIM analyses and dispersion-corrected DFT- computations

In this work, the structures, quantum chemical descriptors, morphologic characterization of the azo-methoxy-calix[4]arene were investigated. The analyses and interpretation of the theoretical and the experimental IR spectroscopy results for the corresponding compounds was performed. The complexation of the azo-methoxy-calix[4]arene with Zn²⁺,Hg²⁺ , Cu²⁺ , Co²⁺, Ni²⁺ , Pb²⁺ and Cd²⁺metal cations has been calculated by the dispersion corrected density functional theory (DFT-D3). The values of the interaction energies show that the specific molecule is more selective to the Cu²⁺ cation. The study of the reactivity parameters confirms that the azo-methoxy-calix[4]arene molecule is more reactive and sensitive to the Cu²⁺ cation than that Co²⁺ and Cd²⁺. In addition, the investigation of the electrophilic and nucleophilic sites has been studied by the molecular electrostatic potential (MEP) analysis. The Hirshfeld surface (HS) analysis of the azo-methoxy-calix[4]arene-Cu²⁺ interaction have been used to understand the Cu⋯hydrogen-bond donors formed between the cation and the specific compound. The Quantum Theory of Atoms in Molecules (QTAIM) via Non covalent Interaction (NCI) analysis was carried out to demonstrate the nature, the type and the strength of the interaction formed between the Cu²⁺ cation and the two symmetrical ligands and the cavity. Finally, the chemical sensor properties based on the Si/SiO₂/Si₃N₄/Azo-methoxy-calix[4]arene for detection of Cu²⁺ cation were studied. Sensing performances are determined with a linear range from 10^-5.2 to 10^-2.2 M. The Si/SiO₂/Si₃N₄/azo-methoxy-calix[4]arene structure is a promoter to have a good performance sensor.

[Early femoral osteolysis following Charnley-Kerboull total hip arthroplasty combining a 22-mm zirconia head on polyethylene]

PURPOSE OF THE STUDY

New bearings have been developed to reduce polyethylene wear. Zirconia ceramic is one proposal with attractive tribologic properties. The purpose of this prospective study was to evaluate the clinical and radiological results at least two years after implantation in a continuous series of total hip arthroplasties combining a zirconia head with polyethylene socket.

MATERIAL AND METHODS

The series included 56total hip arthroplasties performed in 51 patients (30 females and 21 males), mean age 52.2 +/- 12 years (25-76 years). Prostheses were implanted for primary degenerative disease (43%) and dysplasia (27%). The femoral component was a stainless steel stem with a Morse cone measuring 11degrees 25' for 27 hips and 5 degrees 40' for 28 hips. A 22-mm stabilized yttrium tetragonal polycrystalline zirconia head (Y-TZP) was used. The transtrochanteric approach was used for all arthroplaties with implantation of a cemented Charnley-Kerboull prosthesis. Clinical outcome was assessed with the Postel-Merle-d'Aubligné (PMA) score. Acetabular cup wear and periprosthetic osteolysis were measured on successive AP x-rays of the pelvis.

RESULTS

Mean follow-up was 32 months (24-48). None of the patients were lost to follow-up. Mean function score at last follow-up was 17.8 +/- 0.2 (16-18) versus 12.2 +/- 2.6 preoperatively (Wilcoxon, p < 0.0001). There were no cases of implant migration (femoral or acetabular). An endosteal defect by femoral osteolysis in the calcar femoral was observed in 19 of 55 cases. It appeared early between first and second post-operative year and did not progress later. Its surface remained less than 1 cm2 in all cases. We were unable to identify any factor predictive of these osteolytic lesions.

DISCUSSION

The short-term clinical results with this type of arthroplasty was comparable with earlier results described with classical Charnely-Kerboull implants using a metal-polyethylene bearing. The Merkel osteolysis observed in this series occurred early for one-third of the hips with no measurable polyethylene wear. We suggest surgeons should be cautious about using the zirconia head. We are continuing our surveillance of these patients.