Magnesium Modified β-Tricalcium Phosphate Induces Cell Osteogenic Differentiation In Vitro and Bone Regeneration In Vivo

In vitro, in vivo, and clinical studies have shown how the physicochemical and biological properties of β-tricalcium phosphate (β-TCP) work in bone regeneration. This study aimed to improve the properties of β-TCP by achieving optimum surface and bulk β-TCP chemical/physical properties through the hydrothermal addition of magnesium (Mg) and to later establish the biocompatibility of β-TCP/Mg for bone grafting and tissue engineering treatments. Multiple in vitro and in vivo analyses were used to complete β-TCP/Mg physicochemical and biological characterization. The addition of MgO brought about a modest rise in the number of β-TCP surface particles, indicating improvements in alkaline phosphatase (ALP) activity on day 21 (p < 0.05) and in the WST-1assay on all days (p < 0.05), with a corresponding increase in the upregulation of ALP and bone sialoprotein. SEM analyses stated that the surfaces of the β-TCP particles were not altered after the addition of Mg. Micro-CT and histomorphometric analysis from rabbit calvaria critical defects resulted in β-TCP/Mg managing to reform more new bone than the control defects and β-TCP control at 2, 6, and 8 weeks (* p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001, and **** p ≤ 0.0001). The hydrothermal addition of MgO to the β-TCP surfaces ameliorated its biocompatibility without altering its surface roughness resulting from the elemental composition while enhancing cell viability and proliferation, inducing more bone regeneration by osteoconduction in vivo and osteoblastic differentiation in vitro.     

Different changes in mastication between crisp grass carp (Ctenopharyngodon idellus C.et V) and grass carp (Ctenopharyngodon idellus) after heating: The relationship between texture and ultrastructure in muscle tissue

In order to study special mastication of Crisp grass carp (CGC), the relationships between the texture and ultrastructure in raw fresh and heated CGC and grass carp (GC) were studied. In raw samples, all textural results of raw CGC (RCGC) were higher than those of raw GC (RGC). From the ultrastructural results, short muscle fiber diameter, dense fiber density, large collagen amounts, narrow intermyofibrillar spaces and gaps determined the texture of fillets. In the heated samples, the hardness, chewiness, resilience and springiness of heated CGC (HCGC) were higher than in heated CG (HCG). Compared to raw samples, the hardness, fracturability, springiness and chewiness of HCGC were higher than those of RCGC. However, all textural results of HGC were significantly reduced. The ultra-structural results showed that the better mastication of HCGC was connected with denaturation and coagulation of myofibrillar and sarcoplasmic proteins, the low ratio of shrinking in inter-muscular connective tissue, large interstitial material, much less fiber–fiber detachments and myofiber–myocommata detachments.     

湿硫化氢环境中16MnR钢腐蚀的声发射试验研究

采用声发射技术对常温下饱和硫化氢溶液中16MnR钢试样的电解充氢过程进行监测。分析总结了声发射检测信号的特征和来源,并利用金相方法加以验证。试验结果验证了16MnR钢具有一定的抗氢致开裂的能力,表明采用声发射技术可以灵敏地监测该环境下的腐蚀电解过程,对实际检验具有一定的参考价值。     

游乐设施红外热像特征

游乐设施中的大量机械和电气部件在工作中常有较明显的温升,如果温升异常说明设备运行可能存在故障,严重时会引起安全事故。文章首先分析了游乐设施运行过程中关键部件温度升高的原因,并通过采集及分析运行中游乐设施的液压系统、车轮、减速机和电机的红外热像图,初步得到其红外热像特征。由此证明红外热成像检测技术是适用于游乐设施运行状态监测和故障诊断的一种潜在方法。     

压力容器用工业纯钛板材声发射衰减特性

通过对压力容器用工业纯钛板材GR2的声发射衰减特性的研究发现,随着板材厚度从6cm增加到20cm,其声发射的衰减趋势呈增大现象。通过对其不同厚度板材声速的计算发现,声速随着板厚的变化并不出现较大的波动,该结论对钛合金压力容器的声发射特性研究有一定的参考指导意义。     

Heat shock effects on the viability of Cronobacter sakazakii during the dehydration,fermentation, and storage of lactic cultured milk products

In the present study, the viability of heat-shocked and non-shocked Cronobacter sakazakii, a foodborne pathogen, after drying and during the fermentation as well as storage of lactic cultured milk was evaluated. It was found that heat shock increased the viability of C. sakazakii. The pure culture of C. sakazakii, regardless of heat shock, grew rapidly in skim milk with a viable population of ca. 8.59–8.70 log cfu/ml after ca. 48 h of cultivation. Thereafter, the viable population of C. sakazakii remained stable. While in the mix culture with Streptococcus thermophilus or Lactobacillus bulgaricus, a marked reduction in the viable population of C. sakazakii was noted after 24 h of cultivation in skim milk. Nevertheless, at the end of fermentation, the heat-shocked C. sakazakii had a viable population of 5.93–6.01 log cfu/ml, which is significantly higher (P < 0.05) than that of non-shocked cells of 4.96–4.99 log cfu/ml. While the presence of C. sakazakii did not affect the growth of lactic acid bacteria in skim milk. Additionally, heat shock was found to enhance the survival of C. sakazakii after freeze-drying or spray-drying and during the storage of the lactic fermented milk products (pH 4.3) at 5 °C for 48 h.     

Investigation of Neuropathology after Nerve Release in Chronic Constriction Injury of Rat Sciatic Nerve

Peripheral compressive neuropathy causes significant neuropathic pain, muscle weakness and prolong neuroinflammation. Surgical decompression remains the gold standard of treatment but the outcome is suboptimal with a high recurrence rate. From mechanical compression to chemical propagation of the local inflammatory signals, little is known about the distinct neuropathologic patterns and the genetic signatures after nerve decompression. In this study, controllable mechanical constriction forces over rat sciatic nerve induces irreversible sensorimotor dysfunction with sustained local neuroinflammation, even 4 weeks after nerve release. Significant gene upregulations are found in the dorsal root ganglia, regarding inflammatory, proapoptotic and neuropathic pain signals. Genetic profiling of neuroinflammation at the local injured nerve reveals persistent upregulation of multiple genes involving oxysterol metabolism, neuronal apoptosis, and proliferation after nerve release. Further validation of the independent roles of each signal pathway will contribute to molecular therapies for compressive neuropathy in the future.     

焊缝根部缺陷的综合检测

通过综合应用无损检测技术,对船体分段合拢焊缝打底层焊道出现的异常超声波反射信号进行分析及评价。以射线、磁粉等检测手段分析了异常信号所对应的缺陷性质及定性可靠性,为根部微裂纹缺陷检测和提高焊接工艺规范提供了依据。     

面向甲状旁腺检测的椭圆形高斯热图标签分配

近年来基于anchor-free的检测方法相继被提出,它们采取将目标转化为关键点,并在全局高斯热图中进行正负样本的标签分配.这种标签分配策略在一些场景中存在正负样本不平衡的问题,而且在甲状旁腺检测中不能有效反映目标的形状和方向.因此,本文提出了一种新的甲状旁腺检测模型EllipseNet,首先在GT中构建椭圆形状的高斯分布,拟合GT中的真正目标,使得正负样本的分配更加细粒度;同时提出融入目标形状信息的损失函数对目标的位置进行约束,进一步提高检测的精度.此外,模型中构建了多尺度预测,能够更好地检测不同大小的目标,解决甲状旁腺检测中目标尺度不平衡的问题.本文在甲状旁腺数据集上进行实验,结果表明, EllipseNet的AP₅₀达到95%,相比多种主流的检测算法,其检测精度有较大的提升.     

A one-step tuning method for PID controllers with robustness specification using plant step-response data

This paper presents a novel method for proportional-integral-derivative (PID) controller tuning directly using the step response data of the process without resorting to a process model. The required process data are collected from a one-shot step test that can be conducted under either closed-loop or open-loop conditions. The proposed method derives the PID parameters so that the resulting control system behaves as closely as possible to the prescribed reference model. Two structures of the reference model are considered for general design and improved disturbance rejection, respectively. A simple one-dimensional optimization problem is formulated to determine an appropriate reference model for the controlled process. Moreover, the proposed PID tuning method includes a robustness specification based on the maximum peak of sensitivity function that enables the user to explicitly address the trade-off between performance and robustness. Simulation examples are provided to illustrate the superiority of the proposed method over existing (model-based) tuning methods.