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Objective:To investigate the effect of a degradable high-purity magnesium screw in fixing the greater trochanter bone flap of a lateral circumflex femoral artery transverse branch in the treatment of ischemic necrosis of femoral head in young and middle-aged adults.Methods:From February 2017 to February 2019, 12 cases (15 hips) of young and middle-aged patients with avascular necrosis of femoral head were treated in the Department of Orthopaedic of Affiliated Zhongshan Hospital of Dalian University. The age of patients was 30-53 years old. According to Association Research Circulation Osseous (ARCO), 2 hips were graded in stage II b, 4 in ARCO II c, 1 in ARCO III a, 5 in ARCO III b, 2 in ARCO III c and 1 in ARCO IV. The greater trochanter bone flap with a lateral circumferential vascular branch was used to fill the necrotic area, and fixed by a biodegradable high purity magnesium screw in the bone flap transfer. At 3, 6 and 12 months postoperation, the patient came to the hospital outpatient clinic for follow-up, and then were reviewed once a year. Imaging efficacy was evaluated by comparing preoperative and postoperative imaging. The Harris score and Visual Anoalogue Scale (VAS) score were tested at 12 and 24 months after surgery. The Harris score and VAS score before and after surgery were compared by Friedman test, and P<0.05 was considered statistically significant. Results:All 12 patients (15 hips) were entered in the 24-36 months of follow-up. At 12 and 24 months after surgery, Harris score was found at 87 (86, 92) and 90 (87, 92) respertively, which were both higher than that before surgery [59 (52, 74)] with a significant statistical difference ( Z=-3.743, Z=-4.473, P<0.05). However, there was no significant difference in Harris scores between 12 and 24 months after the surgery ( Z=-0.730, P>0.05). At the 12 and 24 months after surgery, VAS score was found at 3 (2, 3) and 2 (1, 3) respertively, which were both lower than that before surgery [6 (5, 6) ] with a significant statistical difference ( Z=-3.560, Z=-4.656, P<0.05). There was no statistical difference in VAS scores between 12 and 24 months after surgery ( Z=-1.095, P>0.05). X-ray and CT scan showed that the bone flaps healed well and the areas of osteonecrosis were repaired. Thirteen femoral heads were in good shape, and 2 femoral heads had further collapse of hips. No patients underwent joint replacement surgery at the time of last follow-up. Conclusion:Fixation of the greater trochanter flap of lateral circumflex femoral artery transverse branch with a degradable high-purity magnesium screw can ensure the healing of the flap at the implantation site and avoid the displacement and shedding of the flap. It is a new therapeutic option to treat the avascular necrosis of femoral head of young and middle-aged people.
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Abstract In the present work, we introduce the theoretical development and a new approach to validate a novel method to calibrate the efficiency of a gamma radiation detector for point sources, which we have named the "Efficiency Extrapolation Method". The method consists in the determination of the detector efficiency using a set of monoenergetic gamma sources, which we will refer to as reference efficiencies. From these values, we will extrapolate the detector efficiency to the complete energy range using the first principle physics of gamma radiation detection theory. Therefore the proposed method corresponds to a semi-empirical one. The determination of reference efficiencies must be done experimentally, but in this work, simulations were performed using FLUKA code. The reference energies will be: 59,54 keV, 661,66 keV and 1 274,54 keV associated to the isotopes 241Am, 137Cs and 22Na respectively. The second part of the method, the extrapolation from the reference energies to the gamma range, will be done over the energies emitted by 152Eu and 133Ba. In general, the results are very good. While the obtained results for energies 53,16 keV and greater than 344,3 keV show an excellent agreement, the results obtained for energies in the middle range are only good.
Resumen En el presente trabajo presentamos el desarrollo teórico y un nuevo enfoque para validar un nuevo método para calibrar la eficiencia de un detector de radiación gamma para fuentes puntuales, al cual hemos llamado el método de extrapolación de la eficiencia. El método consiste en la determinación de la eficiencia del detector usando un conjunto de fuentes gamma monoenergéticas, a las cuales llamaremos eficiencias de referencia. Desde estos valores, extrapolaremos la eficiencia del detector al rango completo de energías usando la física de primeros principios de la teoría de detección de radiación gamma. Por lo tanto el método propuesto corresponde a un método semiempírico. La determinación de las eficiencias de referencia debe hacerse experimentalmente, pero en este trabajo, se realizaron simulaciones usando el código FLUKA. Las energías de referencia serán: 59,54 keV, 661,65 keV y 1 274,54 keV asociadas a los isótopos 241 Am, 137Cs y 22Na respectivamente. La segunda parte del método, la extrapolación desde las energías de referencia hacia el rango gamma de las energías, será realizada sobre las energías emitidas por los isótopos 152Eu y 133Ba. En general, los resultados son muy buenos. Mientras que los resultados obtenidos para las energías de 53,16 keV y mayores que 344,3 keV muestran un excelente acuerdo, los resultados obtenidos para las energías del rango intermedio son solo buenas.
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Objective To compare the in vivo degradation rates of two different kinds of high purity magnesium bone screws by animal experiments, so as to make some suggestions on structural design of high purity magnesium bone screws. Methods High purity magnesium bone screws with threads and without threads were implanted into femoral condyles of New Zealand rabbits separately. Twenty-four rabbits were randomly divided into 3 groups. They were euthanized at 8, 12 and 16 weeks after operation, respectively. The in vivo degradation rates of bone screws with two different shapes were compared through micro-CT scanning and Skyscan CT-analyser software, and the stress changes during the progress of bone screw degradation were analyzed. Results The initial surface area of threaded screws ［(31.70±0.06) mm2］ was significantly greater than that of the non-threaded ones ［(29.56±0.22) mm2］. After 8, 12 and 16 weeks, the volume loss ratios of the threaded screws were (26.01±3.44)%, (33.35±5.05)%, (36.84±6.99)%, respectively, and the volume loss ratios of the non-threaded screws were (22.53±4.78)%, (31.12±6.59)%, (43.22±9.31)%, respectively. At the same time point, there were no significant differences in the volume loss ratio between two kinds of screws. The relationship between the volume reduction and the implantation time was linear for non-threaded screws and gradually decreasing for threaded screws. Conclusions Under the low-bearing condition, different structural design for high purity magnesium screws has no obvious effect on their degradation rate in vivo.
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Objective To study the effects of mechanical load on in vivo degradation performance of high-purity magnesium (HP Mg, 99.99 wt.%) quantitatively. Methods Cylindrical Mg specimens, with a 2 mm diameter and a 14 mm length, were mounted in polyetheretherketone (PEEK) rings to bear compressive stresses ［（6.2±0.6） MPa］, tensile stresses ［（4.6±0.1） MPa］ or no stress (as control). The specimens under different stress states were implanted subcutaneously in dorsal abdominal regions of SD rats for 4 weeks. The mass loss, residual volume and surface morphology of the specimens and staining of surrounding soft tissues were used to analyze the degradation rate of HP Mg. Results Specimens and rings were completely encapsulated by membranous tissues after implantation for 4 weeks. No significant differences in the degradation rates were noted between specimens bearing stress and the control. The corrosion layers of specimens under each stress state were uniform. Conclusions The compressive and tensile stresses (4-6 MPa) could not affect significantly HP Mg degradation performance in vivo. The research findings provide theoretical references for the design and clinical application of Mg-based degradable implants.
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Objective; To investigate the influence of high-purity human menopausal gonadotrophin (HP-hMG) added in different periods of antagonist program COH in the pregnancy outcom of in vitro fertilization-embryo transplantation (IVF-ET) of the patients with normal ovarian function reserve, and to clarify the possible mechanism. Methods; A totol of 142 patients aged from 25 to 40 years old with normal ovarian function underwent IVF treatment were selected. According to the timing of HP-hMG addition, they were divided into early addition group (HP-hMG was added on the first day) and middel and latel addition group (HP-hMG was added on the 6th day). The pregnancy outcomes of the patients were analyzed. Results; Compared with early addition group, the estradiol (E2) level on the day of human chorimic gonadotropin (HCG) injection in middle and late addition group was significantly increased (P = 0.042) and the progesterone (P) level on the day of HCG injection was significantly decreased (P=0. 016), the number of follicles with diameter> 16 mm (P=0. 035) and the number of follicles with diameter >18 mm (P= 0. 026) were increased. Compared with early addition group, the rate of mature follicles in middle and late addition group was increased (P=0. 006), the rate of high quality embroy was increased (P=0. 001), and the cumulative pregnancy rate was increased (P=0. 040). Conclusion: The addition of HP-hMG at middle and late follicular phase can improve the pregnancy outcome in the patients with normal ovarition function reserve under went antagonist program COH.
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Objective To validate the feasibility of the simulationmethod and the reliability of thesimulationresult through comparison between simulation and measurement of the energy spectrum from medical diagnostic X-ray (RQR-Radiation qualities in radiation beans emerging from the X-ray source assembly).Methods A simplified model of the medical diagnostic X-ray RQR radiation quality was established using code of BEAMnrc.The energy spectrum of the same RQR radiation quality were measured through a plane high-purity germanium spectrometer,and compared with the simulationresult.Results The difference of spectral distribution between measurement and simulation was less than 3％,in spite of the convolution processing not happened to the pulse height distribution measured by the spectrometer.And the spectral distribution,fluence,energy fluence,means energy distribution of the radiation was obtained using the code of BEAMDP.Conclusions As indicated above,it is possible to use the simulation of the energy distribution as a foundation for the establishment of X-ray RQR radiation quality.
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Using reversed-phase high performance liquid chromatography, nine ginsenosides were simultaneously separated on an UltimateC₁₈ column with high-resolution and high purity of each chromatographic peak. Adopting the QAMS quality evaluation model for traditional Chinese medicines, ginsenoside Rb₁ was used as the internal reference substance, and the relative correction factors (RCFs) and the relative retention values (RTRs) of ginsenosides Rg₁, Re, Rf, Rb₁, Rc, Rb₂, Rb₃, Rd and 20 (S)-ginsenoside Rg₃ to ginsenoside Rb₁ were calculated individually. Through a series of methodology evaluations, and positioned by the red ginseng reference chromatograph and RTVs, nine ginsenosides in red ginseng were simultaneously assayed only by quantitative determined ginsenoside Rb₁.
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In this paper, we used the Monte Carlo simulations method in a well-type HPGe detector using directly the manufacturer supplied data in order to simulate the effi ciency response at 46.54 keV. The efficiency values were calculated as a function of the fi lling height of the sample into the measurement geometry and results were found in good agreement with experimental data. The main deviations were less than 2.5 % with a mean of 0.9 %, which is totally satisfactory for the purposes of environmental samples measurements. We also present a brief discussion about the response of the detector to different values of its geometric parameters.
En el trabajo se utilizaron los métodos de simulación por Monte Carlo en un detector HPGe tipo pozo, usando directamente los parámetros del fabricante para simular la respuesta en eficiencia a la energía de 46.54 keV. Los valores de efi ciencia se calcularon en función de la altura de la muestra en la geometría de medición y los resultados se correspondieron con los valores experimentales. Las mayores diferencias fueron menores que el 2.5 % con un promedio de 0.9 %, lo que es totalmente satisfactorio para la medición de muestras ambientales. Se presentó una breve discusión sobre la respuesta del detector para diferentes parámetros geométrico.
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A method for the determination of impurities in high pure Nd_2O_3 employing inductively coupled plasma mass spectrometry(ICP-MS) was established, and emphasise was put on the elimination of matrix induced NdO~+ and NdOH~+ spectral interferences using cell collision technology(CCT). Using 10% O_2-10% Ar-80% He as the reaction/collision gas and with proper adjustment of the instrumental parameters, ~(159)Tb,~(165)Ho,~(163)Dy could be quantified at ~(175)TbO,~(179)DyO and ~(181)HoO respectively, while the matrix induced NdO~+ and NdOH~+ spectral interferences could be reduced by 25-70 folds. In addition, different elements were tested as internal standards for matrix effect correction under the CCT mode, and it was found that Re was best. Other impurities including La, Ce, Sm, Eu, Gd, Er, Tm, Yb and Lu were detected under conventional mode, except that Pr was detected under high instrumental resolution mode to eliminate peak tailing interference from Nd. In combination with mathematic correction, the established method can be applied for the determination of impurities in 99.999% Nd_2O_3 products with satisfactory RSDs and recoveries.