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521.
Amplitude modulation excitation for cancellous bone evaluation using a portable ultrasonic backscatter instrumentation
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The ultrasonic backscatter (UB) has the advantage of non-invasively obtaining bone density and structure, expected to be an assessment tool for early diagnosis osteoporosis. All former UB measurements were based on exciting a short single-pulse and analyzing the ultrasonic signals backscattered in bone. This study aims to examine amplitude modulation (AM) ultrasonic excitation with UB measurements for predicting bone characteristics. The AM multiple lengths excitation and backscatter measurement (AM-UB) functions were integrated into a portable ultrasonic instrument for bone characterization. The apparent integrated backscatter coefficient in the AM excitation (AIBAM) was evaluated on the AM-UB instrumentation. The correlation coefficients of the AIBAM estimating volume fraction (BV/TV), structure model index (SMI), and bone mineral density (BMD) were then analyzed. Significant correlations (|R| = 0.82-0.93, p < 0.05) were observed between the AIBAM, BV/TV, SMI, and BMD. By growing the AM excitation length, the AIBAM values exhibit more stability both in 1.0-MHz and 3.5-MHz measurements. The recommendations in AM-UB measurement were that the avoided length (T1) should be lower than AM excitation length, and the analysis length (T2) should be enough long but not more than AM excitation length. The authors conducted an AM-UB measurement for cancellous bone characterization. Increasing the AM excitation length could substantially enhance AIBAM values stability with varying analyzed signals. The study suggests the portable AM-UB instrument with the integration of real-time analytics software that might provide a potential tool for osteoporosis early screening. 相似文献
522.
去卵巢大鼠骨元素代谢紊乱机制研究 总被引:1,自引:0,他引:1
测定了去卵巢大鼠骨元素含量和血清相关激素和细胞因子含量,分析了去卵巢大鼠骨元素代谢紊乱的机制。将健康4月龄SD大鼠18只随机分成3组:正常对照组,假去卵巢大鼠组和去卵巢大鼠组。结果表明,去卵巢大鼠骨Ca、Mg、S、Mn、Zn等含量显著降低,P含量显著升高,血清E2、P、CT、GH等含量显著降低,IL-6、FSH、LH等含量显著升高。提示去卵巢大鼠骨元素代谢紊乱是雌激素水平下降与其他因素共同作用的结果。 相似文献
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Ciro Menale Gaia Tabacco Anda Mihaela Naciu Maria Lucia Schiavone Francesca Cannata Emanuela Morenghi Cristina Sobacchi Andrea Palermo 《Molecules (Basel, Switzerland)》2022,27(12)
The dipeptidyl peptidase 3 (Dpp3) is a ubiquitous zinc-dependent aminopeptidase, participating in the activation or degradation of signaling peptides and in the Keap1–Nrf2 antioxidant pathway. The absence of Dpp3 in the Dpp3 knockout mouse model causes increased osteoclast activity, altered osteogenic function, sustained oxidative stress in the bone tissue, and bone loss. We aimed to assess the association of Dpp3 activity with bone fragility in postmenopausal osteoporosis and the impact of denosumab on enzymatic activity. We conducted a two-phase study including 69 postmenopausal women with severe osteoporosis and 36 postmenopausal women without osteometabolic conditions, as controls (cross-sectional phase). Subjects with severe osteoporosis were assessed at baseline and 14 days after the first denosumab administration (prospective phase). The results showed significant reduction in serum Dpp3 activity (expressed as nmoles of formed product/mg proteins/min) in patients vs. controls (0.791 ± 0.232 vs. 1.195 ± 0.338; p < 0.001), and significant association with bone mass at the femoral neck (r = 0.28, p = 0.02) in patients prior to treatment. We found a negative correlation between C-terminal telopeptide (CTX) or N-terminal pro-peptide of type 1 procollagen (P1NP) levels and Dpp3 activity (respectively, r = −0.29, p = 0.012; and r = −0.2572, p = 0.033). Dpp3 activity did not change after denosumab injection. Our findings support a critical role played by Dpp3 in bone homeostasis as a potential bone protective factor. Additional clinical studies in larger cohorts might explore the implementation of Dpp3 assessment as a biomarker of bone health status. 相似文献
526.
为了探讨利用近红外漫反射光谱判别分析技术快速鉴别非反刍动物源肉骨粉中是否掺有反刍动物源肉骨粉的可行性,收集了来源于国内不同地区的不同种类的肉骨粉样本39个,其中猪、鸡肉骨粉各15个,牛肉骨粉5个和羊肉骨粉4个。通过在非反刍动物源猪或鸡肉骨粉中人为掺入0%~48%的反刍类动物源牛或羊肉骨粉,制备了252个肉骨粉的样本。利用FOSS 6500型近红外光谱仪获取样本光谱,WINISI软件随机选取180个样本作为校正集,72个样本作为独立的验证集。采用基于偏最小二乘回归法(PLS)的判别分析技术,建立了判别分析模型,利用独立的验证集对判别分析模型进行了验证,最优判别分析模型正确判别率为90%。结果表明所建立的判别分析模型可以对非反刍动物源肉骨粉中含有的反刍动物成分进行快速鉴别,但对反刍动物成分含量低于2%的肉骨粉样本,模型的判别精度还有待提高。文章结果为反刍动物源性肉骨粉的鉴别分析提供了一种有效的快速筛选方法。 相似文献
527.
《Mendeleev Communications》2023,33(4):531-533
The fabrication of ceramics based on double phosphates MgNaPO4 and Mg4Na(PO4)3 is considered. Volume changes in phase transformations of MgNaPO4 and Mg4Na(PO4)3 upon thermal treatment in a range of 800–1100 °C and their effect on the microstructure of ceramics are studied. 相似文献
528.
Suong-Hyu Hyon Fengzhe Jin Khosrow Jamshidi Sadami Tsutsumi Tetsuo Kanamoto 《Macromolecular Symposia》2003,197(1):355-368
The hydrostatic molecular orientation technique was used to explore the highest mechanical improvements achievable for poly-L-lactide (PLLA). The mechanical attributes of these materials designed for bone fracture fixation devices, i.e. bending strength and modulus were measured and compared with those prepared by stretching method. The starting samples were prepared by conventional melt extrusion at 200 °C followed by hydrostatic extrusion at 140 °C using glycerin filled extruder. Uniaxially stretched rods were prepared by drawing in silicon oil at 120 °C. The physical properties of these rods are inadequate as mechanical supports in the dynamic healing process of the bone. Moreover, they underwent a marked strength deterioration when immersed in aqueous buffered solution for 90 days. On the other hand, the hydrostatic extrusion technique produced rods with progressively higher bending strength that showed only a small drop after 90 days hydrolytic degradation. Micrographs suggested a superior molecular orientation and packing, which could be associated with the improved performance. The hydrostatic extrusion technique proved to be a safe and effective approach for strengthening biodegradable polymeric materials for dynamic mechanical support in orthopedic medical devices. 相似文献