Assessment of protein changes in farmed giant catfish (Pangasianodon gigas) muscles during refrigerated storage

Farmed giant catfish (Pangasianodon gigas) muscles (dorsal and ventral sites) were stored in a refrigerator (at 4 °C) for 14 days to determine the effect of refrigerated storage on biochemical and physical changes. The analyses were carried out at 0, 2, 4, 7, 10 and 14 days of storage. At day 14, Ca²⁺ ‐ATPase activity markedly decreased when compared to its value at day 1 (>90%), while a small decrease was observed for surface hydrophobicity and reactive sulfhydryls content. Total volatile basic nitrogen and trichloroacetic‐soluble peptide content gradually increased when the storage period was extended. The myosin heavy chain decreased slightly on SDS‐PAGE for both meat cuts with increased storage time. Expressible drip and cooking loss were highest during the first day of storage and slightly decreased with storage time. Instrumental hardness was significantly higher in the ventral compared to the dorsal muscle, while the toughness was the highest at the second day of storage. The muscle bundles with scanning electron microscopy were less attached, resulting in the observed big gaps over increasing storage time. Results indicated that changes of proteins have detrimental effects on the quality attributes of farmed giant catfish muscles during refrigerated storage, particularly physical and biochemical properties.     

Thermal Stability Threshold for Amyloid Formation in Light Chain Amyloidosis

Light chain (AL) amyloidosis is a devastating disease characterized by amyloid deposits formed by immunoglobulin light chains. Current available treatments involve conventional chemotherapy and autologous stem cell transplant. We have recently concluded a phase III trial comparing these two treatments. AL amyloidosis patients who achieve hematological complete response (CR) do not necessarily achieve organ response regardless of the treatment they received. In order to investigate the possible correlation between amyloid formation kinetics and organ response, we selected AL amyloidosis patients from the trial with kidney involvement and CR after treatment. Six patients were selected and their monoclonal immunoglobulin light chains were characterized. The proteins showed differences in their stability and their kinetics of amyloid formation. A correlation was detected at pH 7.4, showing that less stable proteins are more likely to form amyloid fibrils. AL-T03 is too unstable to form amyloid fibrils at pH 7.4. This protein was found in the only patient in the study that had organ response, suggesting that partially folded species are required for amyloid formation to occur in AL amyloidosis.     

多中心骨巨细胞瘤9例报道与文献分析

Objective: The aim of this study was to investigate the clinical, radiographic and histiopathologic features of multicentric giant cell tumor of bone. Methods: All the clinical data of twenty tumors in nine patients of multicentric giant cell tumor that underwent surgical treatment in our department from 1990 to 2010 were retrospectively reviewed, which included three males and six females. The patients ranged from 15 to 45 years at diagnosis, with an average age of 22.3 years. Three of the patients were younger than twenty years of age. Most tumors arose in long bones, especially around the knee. Radiographically, the tumors in long bones usually manifested as expansive lytic lesions involving the metaphysis and extending into the epiphysis. Three tumors in three patients were confined to the metaphysis, and one tumor exhibited bone-forming lesions. All tumors were treated with curettage or resection. Results: The typical "giant cell" could be found in the oncologic examination in all cases. In some areas, such as the fibrohistiocytic regions, reactive bone forming and aneurysmal bone cyst-like changes could be found. Follow-up averaged 3.5 years, ranging from 6 months to 12 years. There was a recurrence of three tumors, and one patient died of pulmonary metastasis. Conclusion: Multicentric giant cell tumor occur often in younger patients than do solitary giant cell tumor. They are frequently present around the knee, and confined to the metaphysis. Each tumor arose independently, rather than being in multiple sites of metastatic lesion that develop from a single tumor. The risk of recurrence depends on the type of surgery that is performed.     

The effect of limited proteolysis by different proteases on the formation of whey protein fibrils

Four proteases: trypsin, protease A, pepsin, and protease M were selected to modify whey protein concentrate (WPC) at a low degree of hydrolysis (0.1, 0.2, and 0.3%) before adjusting to pH 2.0 and heating at 90°C to gain insight into the influence of proteolysis on fibril formation. The kinetics of fibril formation were performed on native and modified WPC using the fluorescent dye thioflavin T in conjunction with transmission electron microscopy and far-UV circular dichroism spectroscopy for the morphological and secondary structural analyses. The change in surface hydrophobicity and content of free sulfhydryl groups were also observed during the formation of fibrils for the native and modified WPC. The content of aggregation and thioflavin T kinetic data indicated that the ability of fibril formation was apparently different for WPC modified by the 4 proteases. Whey protein concentrate modified by trypsin aggregated more during heating and the fibril formation rate was faster than that of the native WPC. Whey protein concentrate modified by the other proteases showed slower aggregation with worse amyloid fibril morphology. Compared with the native WPC, the structure of WPC changed differently after being modified by proteases. The state of α-helix structure for modified WPC played the most important role in the formation of fibrils. Under the mild conditions used in this work, the α-helix structure of WPC modified by trypsin caused little destruction and resulted in fibrils with good morphology; the content of α-helices for WPC modified by other proteases decreased to 36.19 to 50.94%; thus, fibril formation was inhibited. In addition, it was beneficial for the modified WPC to form fibrils such that the surface hydrophobicity increased and the content of free sulfhydryl groups slightly decreased during heating.     

钢混凝土组合型高层和超高层绿色住宅

钢材是一种高强度、高性能的绿色环保材料,具有很高的再循环使用价值.现阶段我国钢结构在住宅方面的运用极少,发展钢结构绿色住宅是必然选择.低层住宅一般采用轻钢结构体系,多、高层住宅则采用钢框架—支撑或钢框架—混凝土混合体系,2种钢结构体系均存在各自的缺点.钢混凝土组合型高层和超高层住宅采用巨型结构体系,由钢筋混凝土构建主结构,由轻钢构建子结构,既保证了主结构的整体稳定性和结构高效性,节约了土地,又保证了子结构的灵活性、可改性和轻质高强,实现了分离式住宅、开放性住宅的最高目标.与之相配套的墙体材料可以采用节能、绿色环保的新型材料,住宅单元均可再生重复利用,节约了资源,提高了住宅环境.该住宅体系为住宅建筑的工业化生产和现场组装,以及住宅建筑的标准化、模数化、系列化和住宅产业化提供了支持.     

组建“巨人企业”加强宏观调控

国有资产投资分散,企业规模不经济,抵消了我国的大国优势。组建“巨人企业”是风险较小的可行方案。“巨人企业”是由若干个同行业或生产同类产品的企业组成的人、财、物、产、供、销一体化的企业。其目的是实现国有资产的规模经营,扩大投资决策的主体。由此可以:发挥新技术、资产和技术人员的作用,提高整个国家的工业水平,有助于稳定市场和资产增殖。     

论钱学森的大成智慧学

文章强调 "大成智慧学"是新世纪的需要, "大成智慧"的核心是科学技术与哲学的结合。为此,不仅要利用人-机结合的思维体系,下苦功夫掌握广博的知识、经验、信息,还要从实际出发,实事求是,善于思考,反复实践,努力树立起反映新世纪的世界观、人生观、科学观、方法论。     

Giant traps on the surface of hydride vapor phase epitaxy-grown free-standing GaN

Extended defects on the top surface of a 250-μm-thick free-standing GaN sample, grown by hydride vapor phase epitaxy (HVPE), were studied by deep level transient spectroscopy (DLTS) and scanning surface potential microscopy (SSPM). For comparison, similar studies were carried out on as-grown HVPE-GaN samples. In addition to the commonly observed traps in as-grown HVPE-GaN, the DLTS measurements on free-standing GaN reveal a very high concentration of deep traps (∼1.0 eV) within about 300 nm of the surface. These traps show nonexponential capture kinetics, reminiscent of those associated with large defects, that can accumulate multiple charges. The SSPM measurements clearly reveal the presence of charged microcracks on the top surface of the sample. It appears that the “giant traps” may be associated with these microcracks, but we cannot rule out the involvement of other extended defects associated with the near-surface damage caused by the polishing/etching procedure.     

Transport Property of La0.67-xSmxSr0.33MnO3 at Heavy Samarium Doping (0.40≤x≤0.60)

The influence of heavy samarion (Sm) doping(0.40≤x≤0.60) on magnetic and electric properties of La0.67-xSmxSr0.33MnO3 was investigated by measuring the magnetization-temperature (M～T) curves, magnetization-magnetic density (M～H) curves, resistivity-temperature(ρ-T) curves and magnetoresistivity-temperature(MR～T) curves of the samples under different temperatures.It is found that, with the increase of Sm doping amount, the samples transform from long-range ferromagnetic order to spin-cluster glass state and anti-ferromagnetic state;and when x=0.60, the transport property becomes abnormal under magnetic background;and the magnetic structure changes and extra magnetic coupling induced by doping leads to colossal magnetoresistance effect.The transport mechanism of metallic conduction at low temperature is mainly electron-magneton interaction and can be fitted by the formula ρ=ρ0 AT4.5, and the insulator-like transport mechanism on high temperature range is mainly the function of variable-range hopping and can be fitted by the formula ρ=ρ0exp(T0/T)1/4.In the formulas above, ρ is resistivity, T is temperature, and A, ρ0, T0 are constants.     

从复杂性的角度分析供应链管理问题

供应链是企业适应市场环境变化而产生的运作模式,也是企业之间竞争与协同发展的产物。供应链是由多个企业组成的复杂供需网络,因此它属于开放的复杂巨系统的范畴,而处理开放的复杂巨系统的有效方法是综合集成研讨体系。该文首先介绍了复杂性的研究情况;分析了供应链的复杂性;指出供应链是一个开放的复杂巨系统;提出用综合集成研讨厅体系的思想研究供应链管理问题,为供应链管理问题的研究提供了一个新的思路。