Early adjunctive diagnostic value of contrast-enhanced ultrasound-related quantitative parameter and its relationship with micro-perfusion of nontraumatic necrosis of femoral head.

OBJECTIVE: The aim of this study is to explore the early diagnostic value of contrast-enhanced ultrasound (CEUS)-related quantitative parameter and its relationship with the micro-perfusion of nontraumatic necrosis of the femoral head. PATIENTS AND METHODS: According to the random and double-blind method, the patients with non-traumatic femoral head necrosis diagnosed and treated in our hospital from July 2019 to January 2022 were selected as the subjects (the research group). According to the staging of the International Society of Bone Circulation for Femoral Head Necrosis, 89 patients with stage Ⅱ and Ⅲ A were included (39 patients with stage Ⅱ and 50 patients with stage Ⅲ A). 25 patients who conducted physical examination in our hospital during the same time were taken as the control group. Quantitative parameters of CEUS were analyzed. The content of serum vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) were evaluated. The relationship among the quantitative parameters of CEUS, the expression of VEGF and BMP-2 in serum and the patient's condition, and the value for assisting the early diagnosis of nontraumatic femoral head necrosis were analyzed. RESULTS: The body mass, body mass index (BMI), blood lipid, and cholesterol levels were much higher in the research group than in the control group (p < 0.05). The research group had a markedly higher slope of ascending branch (AS), strength enhancement index (EI), and VEGF and obviously lower decay slope (DS), mean transit time (MTT), and time to peak (TTP) than the control group (p < 0.05). In the research group, compared to stage Ⅱ, the levels of AS, EI, and VEGF in stage Ⅲ A patients were memorably higher, and the levels of DS, MTT, TTP and BMP-2 were dramatically lower (p < 0.05). Pearson's correlation test showed that AS, EI, and VEGF were positively correlated with the patients' condition, while DS, MTT, TTP and BMP-2 were negatively correlated with the patients' condition (p < 0.05). The receiver operating characteristic (ROC) curve analysis showed that the diagnostic area under the curve (AUC) of quantitative parameters of CEUS was 0.961, with sensitivity and specificity of 88.0% and 97.4%, respectively. The AUC of the combined detection of VEGF and BMP-2 was 0.945 with sensitivity and specificity of 82.3% and 87.5%, respectively, and the combined detection had a high diagnostic value (p < 0.05). CONCLUSIONS: The quantitative parameters of CEUS were of great value in the early diagnosis of nontraumatic necrosis of the femoral head with microvascular perfusion and the patients' condition, and provided a reference for the clinical treatment of non-traumatic necrosis of the femoral head. These parameters were expected to be useful indicators for judging the efficacy before and after treatment.

ZnO nanocone: application in fabrication of the smallest whispering gallery optical resonator.

ZnO semiconductors at the micro- and nanometre scales are attractive in optical, magnetic, and electronic applications because of their particular features and excellent properties. The whispering gallery mode (WGM) is a general and effective type to amplify the intensity of the luminescence emission, and has gained extensive application in lasing and microcavities. In this contribution, we reported that the smallest whispering gallery optical resonator has been achieved in an individual ZnO nanocone whose diameter gradually reduces from bottom to top in the range of 700 to 50 nm. Using the monochromatic cathodoluminescence (CL) equipment attached at a scanning electron microscopy, we observed the alternating patterns of bright and dark rings from the monochromatic CL image of an individual ZnO nanocone, which is attributed to the WGM-like enhanced luminescence emission when the ZnO nanocone is considered as an optical resonator. The smallest mode number of WGM, N=0, was observed in the ZnO nanocone with a radius of 55 nm for the considered light wavelength of 380 nm, and with a radius of 81 nm for the considered light wavelength of 500 nm, respectively. These results showed that the smallest whispering gallery optical resonator from an individual ZnO nanocone has been fabricated. Experiments are in good agreement with both theoretical predictions and computer simulations based on the finite-difference time domain method with perfectly matched layer boundary conditions. These findings provided valuable information for applications of ZnO micro- and nanostructures in optoelectronic devices.

Ion exchange in purification.

Biochemicals have large complex three-dimensional structures with multiple weak acid and weak base groups on their surfaces. The ionization of these groups results in heterogeneous charge structures and complex ion-exchange equilibria. In this chapter the ion-exchange equilibria of amino acids are reviewed first. The ionization of the alpha-COOH group has a strong effect on the apparent equilibrium affinities of amino acids. Salt concentration and pH can also significantly affect the apparent affinities and valences. The implications on the ion-exchange equilibria of peptides and proteins are discussed. The second focus of this chapter is on the local equilibrium models of multicomponent chromatographic processes. The differences between unidirectional and two-way flow conditions, linear and nonlinear systems, elution and displacement processes, and isocratic and gradient operations are discussed. Fundamental analysis of these phenomena is applied to formulate strategies to shorten cycle time, improve resolution, raise product concentration, and increase throughput.