Supramolecular recognition enhanced electrochemical sensing: ß-cyclodextrin and Pd nanoparticle co-decorated 3D reduced graphene oxide nanocomposite-modified glassy carbon electrode for the quantification of ractopamine.

Ractopamine (RAC) is universally known for improving lean meat percentage in livestock and thus is widely introduced as a feed additive. However, it is difficult to eliminate the RAC residue in animal tissues from the biological system and will inevitably harm human health. Hence, detecting RAC molecules in biological samples is extremely significant. Herein, a novel strategy of supramolecular recognition-enhanced electrochemical sensing is presented. This platform was constructed by coupling ß-cyclodextrin (ß-CD) with palladium nanoparticles (Pd NPs)-functionalized three-dimensional reduced graphene oxide (3D-rGO) to form a nanocomposite (3D-rGO/Pd/ß-CD), which was further used to modify a glassy carbon electrode (GCE) for RAC detection. Benefiting from the attractive electrical conductivity and catalytic activity of 3D-rGO/Pd, as well as the unique small-molecule-recognition ability of ß-CD demonstrated by 1H NMR spectrum, which revealed the 1 : 2 binding mode of RAC with ß-CD, increased peak current signals of RAC were observed in the cyclic voltammetry (CV) test. Under optimized conditions, the wide linear concentration range spanned 1-95 µM, along with a relatively low detection limit of 0.12 µM (S/N = 3), as evidenced by the differential pulse voltammetry (DPV) approach. The platform also exhibited satisfactory stability and fine reproducibility, as well as high selectivity and good anti-interference capability. Moreover, this as-obtained sensor was efficiently applied in pork samples with a high recovery rate (96.44-103.99%), which provides a promising view of its electrochemical biosensing ability in practical applications.

A case of unexpected death due to primary angiitis of the central nervous system.

Primary angiitis of the central nervous system (PACNS) is a rare and fatal cerebral vasculitis mainly involving the arteriole of the pia mater, cerebral cortex, and spinal cord. It has an insidious onset atypical symptoms. In this paper, we reported an unexpected death due to cerebral hemorrhage caused by PACNS. According to the typical clinical manifestations (headache, dizziness, weakness of the limbs, temporary blurred vision, etc.) and pathological examination (wide degeneration and fibrinoid necrosis of blood vessel walls with inflammatory cell infiltration), as well as hematoxylin-eosin staining, immunohistochemistry for CD15 + and gram staining, we finally determined that the patient died due to cerebral vascular rupture and hemorrhage caused by PACNS. This case illustrates the value and key points of autopsy in evaluating sudden deaths.

A selective electrochemical chiral interface based on a carboxymethyl-ß-cyclodextrin/Pd@Au nanoparticles/3D reduced graphene oxide nanocomposite for tyrosine enantiomer recognition.

Palladium@gold nanoparticle modified three-dimensional-reduced graphene oxide (3D-rGO/Pd@Au) was coupled with carboxymethyl-ß-cyclodextrin to form a novel nanocomposite (3D-rGO/Pd@Au/CM-ß-CD). The 3D-rGO/Pd@Au/CM-ß-CD served as a chiral sensing interface for the electrochemical enantiorecognition of tyrosine (Tyr) via a differential pulse voltammetry (DPV) approach. The 3D-rGO/Pd@Au demonstrates good electrical conductivity and efficient catalytic activity as an electrochemical indicator. Simultaneously, the CM-ß-CD displays a supramolecular chiral selectivity to reveal a higher binding affinity to the target L-tyrosine (L-Tyr) than to D-tyrosine (D-Tyr). Under the optimized determining conditions, the oxidation peak current ratio of L-Tyr to D-Tyr (IL/ID) was 2.12, meanwhile, the peak currents of the two isomers were linearly proportional to the concentration over the range of 0.8-130 µM with LODs of 52 nM and 96 nM for L- and D-Tyr (S/N = 3), respectively. This approach exhibits distinguished sensitivity, excellent selectivity and good reproducibility, as well as great stability, which can accurately determine the relative content of L- or D-Tyr enantiomers in a racemic solution.

Optimizing Photochirogenic Performance by Solvent-Driven Conformational Fixation in Enantiodifferentiating Photoisomerization of (Z)-Cyclooctene Mediated by Sensitizing ß-Cyclodextrin Hosts.

Catalytic enantiodifferentiating photoisomerization of cyclooctene (1Z) included and sensitized by regioisomeric 6-O-(o-, m-, and p-methoxybenzoyl)-ß-cyclodextrins (CDs) was performed under a variety of solvent conditions for higher enantioselectivities. The enantiomeric excess (ee) of chiral (E)-isomer (1E) produced was a critical function of all the internal and external factors examined, in particular, the sensitizer structure and the solvent conditions, to afford (R)-1E in record-high ee's of up to 67% upon sensitization with the meta-substituted ß-CD host in water and salt solutions but neither in 50% aqueous ethanol nor with the ortho- and para-substituted hosts. The mechanistic origin of the sudden ee enhancement achieved under the specific conditions is discussed on the basis of the circular dichroism spectral behaviors upon substrate inclusion and the compensatory enthalpy-entropy relationship of the activation parameters for the enantiodifferentiating photoisomerization.

[Retrospective analysis of maxillary sinus augmentation for endosseous implants].

OBJECTIVE: To determine the long-term clinical outcome and predictability of the maxillary sinus augmentation procedure. METHODS: Seventy-four patients underwent 100 sinus bone graft procedure and 206 implants were placed. The patients were followed up for 1-9 years, with an average of 3.46 +/- 1.65 years after implant placement. RESULTS: The 5-year cumulative survival rate (CSR) of implants was 92.28%. Only 8 implants failed and no sinusitis occurred. CONCLUSIONS: Sinus bone graft is an adjunctive procedure with a predictable outcome in patients with severely atrophied posterior maxilla.