Amplitude modulation excitation for cancellous bone evaluation using a portable ultrasonic backscatter instrumentation

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 (AIB_AM) was evaluated on the AM-UB instrumentation. The correlation coefficients of the AIB_AM 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 AIB_AM, BV/TV, SMI, and BMD. By growing the AM excitation length, the AIB_AM 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 AIB_AM 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.     

Nonlinear inversion of ultrasonic guided waves for in vivo evaluation of cortical bone properties

Ultrasonic guided waves (UGWs), which propagate throughout the entire thickness of cortical bone, are attractive for the early diagnosis of osteoporosis. However, this is challenging due to the impact of soft tissue and the inherent difficulties related to multiparametric inversion of cortical bone quality factors, such as cortical thickness and bulk wave velocity. Therefore, in this research, a UGW-based multi-parameter inversion algorithm is developed to predict strength-related factors. In simulation, a free plate (cortical bone) and a bilayer plate (soft tissue and cortical bone) are used to validate the proposed method. The inversed cortical thickness (CTh), longitudinal velocity (V_L) and transverse velocity (V_T) are in accordance with the true values. Then four bovine cortical bone plates were used in in vitro experiments. Compared with the reference values, the relative errors for cortical thickness were 3.96%, 0.83%, 2.87%, and 4.25%, respectively. In the in vivo measurements, UGWs are collected from the tibias of 10 volunteers. The theoretical dispersion curves depicted by the estimated parameters (V_T, V_L, CTh) match well with the extracted experimental ones. In comparison with dual-energy x-ray absorptiometry, our results show that the estimated transverse velocity and cortical thickness are highly sensitive to osteoporosis. Therefore, these two parameters (CTh and V_T) of long bones have potential to be used for diagnosis of bone status in clinical applications.     

Experiments on the local heat transfer characteristics of a circulating fluidized bed

The role of particle diameter in the heat transfer of a gas–solid suspension to the walls of a circulating fluidized bed was studied for particles of uniform size. This work reports and analyzes new experimental results for the local bed to wall heat transfer coefficient, not including the radiation component, in a long active heat transfer surface length laboratory bed, which extend previous findings and clear up some divergences. The research included determining the effects of extension and location of the heat transfer surface, circulating solids mass flux and average suspension density. An experimental set-up was built, with a 72.5 mm internal diameter riser, 6.0 m high, composed of six double pipe heat exchangers, 0.93 m high, located one above the other. Five narrow sized diameter quartz sand particles − 179, 230, 385, 460 and 545 μm − were tested. Temperature was kept approximately constant at 423 K and the superficial gas velocity at 10.5 m/s. The major influence of suspension density on the wall heat transfer was confirmed, and contrary to other authors, a significant effect of particle size was found, which becomes more relevant for smaller particles and increasing suspension density. It was observed that the extension of the heat transfer surface area did not influence the heat transfer coefficient for lengths greater than 0.93 m.The heat transfer surface location did not show any effect, except for the exchanger at the botton of the riser. A simple correlation was proposed to calculate the heat transfer coefficient as a function of particle diameter and suspension density.     

Further insights into the assessment of cell cycle phases by FTIR microspectroscopy

Cell growth and replication occurs in an orderly manner through a set of tightly coordinated physiological events, classified as G0, G1, S, G2 and M in conformity to their characteristics. In a previous work, by combining the results of flow cytometry (FC) using propidium iodide (PI) staining, PI-FC, and Fourier Transform Infrared Microspectroscopy (FTIRM), we gathered information to classify live B16 cells into three different set of phases (G0/G1, S and G2/M), according to their nucleic acid content measured as the area integral of the Phosphate I band (PhI, 1274–1182 cm⁻¹). In this work, we demonstrate that, once built a calibration dataset for a cell line determining the intervals of the PhI area integral related to each phase of the cell cycle, such data can be used for assigning the stage to which a live cell belongs without the support of FC. In addition, we evaluate the spectral profile of early G1 B16 cells, and compare it with the one of G0 and late G1 cell cycle phases. FTIRM highlights that G0 and G1 phases are a continuum, where the content of RNA of early G1 cells is in between G0 and late G1, and the overall nucleic acid content varies accordingly. In the paper, we also pinpoint the effects on synchronization protocols on cellular biochemistry, further strengthening the potentialities of a totally label-free methodology for cell sorting. Finally, we demonstrate that the general concept behind the proposed approach may be extended to other mammalian cell lines: human bone osteosarcoma (U2OS) cells were tested.     

Amdigenols E and G,long carbon-chain polyol compounds,isolated from the marine dinoflagellate Amphidinium sp.

The novel polyol compounds, amdigenols E and G, were isolated from the dinoflagellate Amphidinium sp. that was found to adhere to the surface of the marine alga Digenea simplex. The structures of the two amdigenols were elucidated by NMR spectroscopy and ESI–CID-MS/MS analyses. Both amdigenols E and G shared partial structures with amdigenol A. Amdigenols E and G inhibited N-type Ca²⁺ channel-opening.     

多发性骨髓瘤的骨髓形态学分析与临床应用

目的研究多发性骨髓瘤的骨髓形态学特征,探讨骨髓形态学在多发性骨髓瘤诊断中的临床应用价值。方法对广东医学院附属医院63例多发性骨髓瘤病人进行骨髓涂片及细胞染色和进行检验诊断分析。结果 94%的患者骨髓增生度都达到增生活跃以上,只有6%的是增生低下或极度低下,瘤细胞数量﹥15%,根据形态可分为四类;病人骨髓其他系包括巨核系、粒系、红系和淋巴系细胞都不同程度减少和受抑制。结论骨髓形态学分析是多发性骨髓瘤诊断和治疗疗效监测具有重要的临床应用价值,具有广泛开展的必要性和意义。     

Flow induced crystallization of long chain branched polypropylenes under weak shear flow

In the present work long chain branched polypropylene (LCB PP) polymers were prepared by linear polypropylene and multi-functional monomer through melt grafting reaction. A quantitative rheological method was adopted to analysis the structure parameters of LCB PP. The effects of chain branched level on the crystallization kinetics of PP were investigated by rheology, differential scanning calorimetry, polarized optical microscope and wide-angle X-ray diffraction. The dynamic viscoelastic properties of LCB PP showed that the increase in the chain branched level caused a typical deviation from the terminal behavior and a different distribution of the melt relaxation spectrum in the long relaxation time regime. It was found that the chain branched level had a significant effect on the flow induced crystallization (FIC) process of PP melts. The crystallization of LCB PP was more sensitive to shear flow than that of linear PP during induced period at low shear rates. This result also indicated that the longer relaxation time of the polymer chains played an important role in the nucleation of PP under shear flow fields. LCB PP with high chain branched level showed accelerated crystallization kinetics in comparison with that with low chain branched level.     

Crystal and magnetic structures of the brownmillerite compound Ca2Fe1.039(8)Mn0.962(8)O5

The crystal and magnetic structures of the brownmillerite material, Ca₂Fe_1.039(8)Mn_0.962(8)O₅ were investigated using powder X-ray and neutron diffraction methods, the latter from 3.8 to 700 K. The compound crystallizes in Pnma space group with unit cell parameters of a=5.3055(5) Å, b=15.322(2) Å, c=5.4587(6) Å at 300 K. The neutron diffraction study revealed the occupancies of Fe³⁺ and Mn³⁺ ions in both octahedral and tetrahedral sites and showed some intersite mixing and a small, ∼4%, Fe excess. While bulk magnetization data were inconclusive, variable temperature neutron diffraction measurements showed the magnetic transition temperature to be 407(2) K below which a long range antiferromagnetic ordering of spins occurs with ordering wave vector k=(000). The spins of each ion are coupled antiferromagnetically with the nearest neighbors within the same layer and coupled antiparallel to the closest ions from the neighboring layer. This combination of intra- and inter-layer antiparallel arrangement of spins forms a G-type magnetic structure. The ordered moments on the octahedral and tetrahedral sites at 3.8 K are 3.64(16) and 4.23(16) μ_B, respectively.     

新型橙红色长余辉发光材料Gd2O2S:Sm3+的合成

采用固相反应法合成了一种新型的橙红色长余辉磷光粉Gd2O2S：Sm^3 ，并用全自动X射线粉末衍射仪表征了其结构，用荧光光谱仪测试了其激发、发射光谱、余辉光谱和余辉衰减曲线。XRD证实其为单相的硫氧化钆。该磷光体呈现Sm^3 的三个特征发射(^4G5/2→^6HJ,J=5／2，7／2，9／2)。经紫外或可见光激发后能观察到长时间明亮的余辉发光。